This document discusses location management and handoff management in mobile databases. It covers topics like location lookup, location update, location area, paging area, types of handoff (hard, soft), and challenges of mobility like ensuring atomicity, consistency, isolation and durability of transactions. It also summarizes different mobile transaction models like HiCoMo, Moflex, Kangaroo and Mobilaction that aim to process transactions reliably in a mobile environment with intermittent connectivity.
The document discusses various protocols and security aspects related to IoT. It provides details on protocols such as IEEE 802.15.4, BACnet, Modbus, KNX, Zigbee etc. It also outlines vulnerabilities in IoT like unauthorized access, information corruption, DoS attacks. Key elements of IoT security discussed are identity establishment, access control, data security, non-repudiation and availability. Security requirements and models for IoT are also mentioned.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
Concurrency Control in Distributed Database.Meghaj Mallick
The document discusses various techniques for concurrency control in distributed databases, including locking-based protocols and timestamp-based protocols. Locking-based protocols use exclusive and shared locks to control concurrent access to data items. They can be implemented using a single or distributed lock manager. Timestamp-based protocols assign each transaction a unique timestamp to determine serialization order and manage concurrent execution.
This document discusses various strategies for register allocation and assignment in compiler design. It notes that assigning values to specific registers simplifies compiler design but can result in inefficient register usage. Global register allocation aims to assign frequently used values to registers for the duration of a single block. Usage counts provide an estimate of how many loads/stores could be saved by assigning a value to a register. Graph coloring is presented as a technique where an interference graph is constructed and coloring aims to assign registers efficiently despite interference between values.
The document describes a simple code generator that generates target code for a sequence of three-address statements. It tracks register availability using register descriptors and variable locations using address descriptors. For each statement, it determines the locations of operands, copies them to a register if needed, performs the operation, updates the register and address descriptors, and stores values before procedure calls or basic block boundaries. It uses a getreg function to determine register allocation. Conditional statements are handled using compare and jump instructions and condition codes.
The document discusses various data link layer protocols. It begins by introducing stop-and-wait and sliding window protocols. It then provides an example of a stop-and-wait protocol where a frame is lost, leading the sender to retransmit a duplicate frame. Next, it discusses sliding window protocols and provides an example where the window allows multiple outstanding frames. Finally, it gives an example of a one-bit sliding window protocol that uses acknowledgments to control the window.
The document discusses various protocols and security aspects related to IoT. It provides details on protocols such as IEEE 802.15.4, BACnet, Modbus, KNX, Zigbee etc. It also outlines vulnerabilities in IoT like unauthorized access, information corruption, DoS attacks. Key elements of IoT security discussed are identity establishment, access control, data security, non-repudiation and availability. Security requirements and models for IoT are also mentioned.
The document provides an overview of IEEE 802.11 standards for wireless local area networks. It discusses the creation of 802.11 by IEEE, the physical layer, frame formats, and various 802.11 protocols including 802.11b, 802.11a, 802.11g, 802.11n, and 802.11ac. It also describes the media access control including CSMA/CA and security features like authentication and WEP encryption.
Concurrency Control in Distributed Database.Meghaj Mallick
The document discusses various techniques for concurrency control in distributed databases, including locking-based protocols and timestamp-based protocols. Locking-based protocols use exclusive and shared locks to control concurrent access to data items. They can be implemented using a single or distributed lock manager. Timestamp-based protocols assign each transaction a unique timestamp to determine serialization order and manage concurrent execution.
This document discusses various strategies for register allocation and assignment in compiler design. It notes that assigning values to specific registers simplifies compiler design but can result in inefficient register usage. Global register allocation aims to assign frequently used values to registers for the duration of a single block. Usage counts provide an estimate of how many loads/stores could be saved by assigning a value to a register. Graph coloring is presented as a technique where an interference graph is constructed and coloring aims to assign registers efficiently despite interference between values.
The document describes a simple code generator that generates target code for a sequence of three-address statements. It tracks register availability using register descriptors and variable locations using address descriptors. For each statement, it determines the locations of operands, copies them to a register if needed, performs the operation, updates the register and address descriptors, and stores values before procedure calls or basic block boundaries. It uses a getreg function to determine register allocation. Conditional statements are handled using compare and jump instructions and condition codes.
The document discusses various data link layer protocols. It begins by introducing stop-and-wait and sliding window protocols. It then provides an example of a stop-and-wait protocol where a frame is lost, leading the sender to retransmit a duplicate frame. Next, it discusses sliding window protocols and provides an example where the window allows multiple outstanding frames. Finally, it gives an example of a one-bit sliding window protocol that uses acknowledgments to control the window.
The document discusses IEEE 802.11 standards for wireless LANs. It describes the formation of the IEEE 802.11 working group in 1990 to develop wireless LAN MAC and physical specifications. It then summarizes key IEEE 802.11 standards including 802.11a, 802.11b, 802.11g, 802.11n, and more recent standards. It provides an overview of IEEE 802.11 architecture including the basic service set, extended service set, and distribution system. It also discusses services provided at the MAC layer such as reliable data delivery, access control, and security.
What is Heuristics?
A heuristic is a technique that is used to solve a problem faster than the classic methods. These techniques are used to find the approximate solution of a problem when classical methods do not. Heuristics are said to be the problem-solving techniques that result in practical and quick solutions.
Heuristics are strategies that are derived from past experience with similar problems. Heuristics use practical methods and shortcuts used to produce the solutions that may or may not be optimal, but those solutions are sufficient in a given limited timeframe.
History
Psychologists Daniel Kahneman and Amos Tversky have developed the study of Heuristics in human decision-making in the 1970s and 1980s. However, this concept was first introduced by the Nobel Laureate Herbert A. Simon, whose primary object of research was problem-solving.
Why do we need heuristics?
Heuristics are used in situations in which there is the requirement of a short-term solution. On facing complex situations with limited resources and time, Heuristics can help the companies to make quick decisions by shortcuts and approximated calculations. Most of the heuristic methods involve mental shortcuts to make decisions on past experiences.
Heuristic techniques
The heuristic method might not always provide us the finest solution, but it is assured that it helps us find a good solution in a reasonable time.
Based on context, there can be different heuristic methods that correlate with the problem's scope. The most common heuristic methods are - trial and error, guesswork, the process of elimination, historical data analysis. These methods involve simply available information that is not particular to the problem but is most appropriate. They can include representative, affect, and availability heuristics.
We can perform the Heuristic techniques into two categories:
Direct Heuristic Search techniques in AI
It includes Blind Search, Uninformed Search, and Blind control strategy. These search techniques are not always possible as they require much memory and time. These techniques search the complete space for a solution and use the arbitrary ordering of operations.
The examples of Direct Heuristic search techniques include Breadth-First Search (BFS) and Depth First Search (DFS).
Weak Heuristic Search techniques in AI
It includes Informed Search, Heuristic Search, and Heuristic control strategy. These techniques are helpful when they are applied properly to the right types of tasks. They usually require domain-specific information.
The examples of Weak Heuristic search techniques include Best First Search (BFS) and A*.
About Naming Concepts in Distributed systems.
More about its services, its types & the approaches of implementation for Name Space & Name Resolution and Locating Entities Approaches with example diagrams.
This document discusses synchronization in mobile computing systems. It describes how data is replicated and distributed across mobile devices, personal computers, and remote servers. It then discusses various synchronization techniques used to maintain consistency between distributed copies of data, including one-way synchronization initiated by the server or client, two-way synchronization, and refresh synchronization. The document also covers domain-specific rules that govern how data is synchronized across different platforms and data formats.
Cluster analysis is an unsupervised machine learning technique that groups similar data objects into clusters. It finds internal structures within unlabeled data by partitioning it into groups based on similarity. Some key applications of cluster analysis include market segmentation, document classification, and identifying subtypes of diseases. The quality of clusters depends on both the similarity measure used and how well objects are grouped within each cluster versus across clusters.
The document discusses the UMTS Terrestrial Radio Access Network (UTRAN) which connects mobile devices to telephone networks and the internet. It contains Node B base stations and Radio Network Controllers that make up the radio access network. There are physical, transport, and logical channels that deal with different information flows and tasks between the network and terminals. The document outlines the lu, Uu, lub, and lur interfaces that connect internally and externally to other network entities like the core network and between RNCs and Node Bs. It notes that high uplink data transmission speed from the UE to base stations is important for high connectivity speeds compared to downlink transmission speed from base stations to the UE.
There are 5 levels of virtualization implementation:
1. Instruction Set Architecture Level which uses emulation to run inherited code on different hardware.
2. Hardware Abstraction Level which uses a hypervisor to virtualize hardware components and allow multiple users to use the same hardware simultaneously.
3. Operating System Level which creates an isolated container on the physical server that functions like a virtual server.
4. Library Level which uses API hooks to control communication between applications and the system.
5. Application Level which virtualizes only a single application rather than an entire platform.
Fault tolerance is important for distributed systems to continue functioning in the event of partial failures. There are several phases to achieving fault tolerance: fault detection, diagnosis, evidence generation, assessment, and recovery. Common techniques include replication, where multiple copies of data are stored at different sites to increase availability if one site fails, and check pointing, where a system's state is periodically saved to stable storage so the system can be restored to a previous consistent state if a failure occurs. Both techniques have limitations around managing consistency with replication and overhead from checkpointing communications and storage requirements.
Problem solving
Problem formulation
Search Techniques for Artificial Intelligence
Classification of AI searching Strategies
What is Search strategy ?
Defining a Search Problem
State Space Graph versus Search Trees
Graph vs. Tree
Problem Solving by Search
This document discusses asynchronous data transfer between independent units. It describes two methods for asynchronous transfer - strobe control and handshaking. Strobe control uses a single control line to time each transfer, while handshaking introduces a second control signal to provide confirmation between units. Specifically, it details the handshaking process, which involves control signals like "data valid" and "data accepted" or "ready for data" to coordinate placing data on the bus and accepting data between a source and destination unit.
The document discusses search strategies in artificial intelligence. It defines key terms like search space, start state, goal test, and search tree. It describes properties of search algorithms like completeness, optimality, time complexity, and space complexity. It differentiates between uninformed searches, which do not use domain knowledge, like breadth-first search and depth-first search, and informed searches, which use heuristics to guide the search more efficiently, like greedy search and A* search. The document outlines the differences between informed and uninformed searches.
The document discusses different distribution design alternatives for tables in a distributed database management system (DDBMS), including non-replicated and non-fragmented, fully replicated, partially replicated, fragmented, and mixed. It describes each alternative and discusses when each would be most suitable. The document also covers data replication, advantages and disadvantages of replication, and different replication techniques. Finally, it discusses fragmentation, the different types of fragmentation, and advantages and disadvantages of fragmentation.
The document provides an overview of GSM architecture including:
1. GSM uses a cellular network architecture with base stations, base station controllers, mobile switching centers, and databases to manage subscriber identity and location.
2. The network allows for voice calls and data services including SMS, and provides security through subscriber authentication and encryption.
3. GSM is a global standard that enabled international roaming and continues to evolve to support higher data rates through technologies like GPRS, EDGE, and WCDMA.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
The document discusses various protocols and approaches for improving the performance of TCP over wireless networks. It notes that wireless networks have higher bit error rates, lower bandwidth, and mobility issues compared to wired networks. Several protocols are described that aim to distinguish wireless losses from congestion losses to avoid unnecessary TCP reactions:
- Indirect TCP splits the connection and handles losses locally at the base station. Snoop caches packets at the base station for retransmission.
- Mobile TCP further splits the connection and has the base station defer acknowledgments. It can also inform the sender about handoffs versus interface switches.
- Multiple acknowledgments uses two types of ACKs to isolate the wireless and wired portions of the network.
-
1. Planning involves finding a sequence of actions that achieves a goal starting from an initial state. It uses a set of operators that define the possible actions and their effects.
2. A plan is a sequence of operator instances that transforms the initial state into a goal state. Classical planning assumes fully observable, deterministic environments.
3. Planning problems can be represented using a logical language that describes states, goals, actions and their preconditions and effects. This representation allows planning algorithms to operate over problems.
In the field of artificial intelligence (AI), planning refers to the process of developing a sequence of actions or steps that an intelligent agent should take to achieve a specific goal or solve a particular problem. AI planning is a fundamental component of many AI systems and has applications in various domains, including robotics, autonomous systems, scheduling, logistics, and more. Here are some key aspects of planning in AI:
Definition of Planning: Planning involves defining a problem, specifying the initial state, setting a goal state, and finding a sequence of actions or a plan that transforms the initial state into the desired goal state while adhering to certain constraints.
State-Space Representation: In AI planning, the problem is often represented as a state-space, where each state represents a snapshot of the system, and actions transform one state into another. The goal is to find a path through this state-space from the initial state to the goal state.
Search Algorithms: AI planning typically relies on search algorithms to explore the state-space efficiently. Uninformed search algorithms, such as depth-first search and breadth-first search, can be used, as well as informed search algorithms, like A* search, which incorporates heuristics to guide the search.
Heuristics: Heuristics are used in planning to estimate the cost or distance from a state to the goal. Heuristic functions help inform the search algorithms by providing an estimate of how close a state is to the solution. Good heuristics can significantly improve the efficiency of the search.
Plan Execution: Once a plan is generated, the next step is plan execution, where the agent carries out the actions in the plan to achieve the desired goal. This often requires monitoring the environment to ensure that the actions are executed as planned.
Temporal and Hierarchical Planning: In more complex scenarios, temporal planning deals with actions that have temporal constraints, and hierarchical planning involves creating plans at multiple levels of abstraction, making planning more manageable in complex domains.
Partial and Incremental Planning: Sometimes, it may not be necessary to create a complete plan from scratch. Partial and incremental planning allows agents to adapt and modify existing plans to respond to changing circumstances.
Applications: Planning is used in a wide range of applications, from manufacturing and logistics (e.g., scheduling production and delivery) to robotics (e.g., path planning for robots) and game playing (e.g., chess and video games).
Challenges: Challenges in AI planning include dealing with large search spaces, handling uncertainty, addressing resource constraints, and optimizing plans for efficiency and performance.
AI planning is a critical component in creating intelligent systems that can autonomously make decisions and solve complex problems.
Client-Centric Consistency
Provide guarantees about ordering of operations only for a single client, i.e.
Effects of an operations depend on the client performing it
Effects also depend on the history of client’s operations
Applied only when requested by the client
No guarantees concerning concurrent accesses by different clients
Assumption:
Clients can access different replicas, e.g. mobile users
This document provides an overview of artificial intelligence (AI) including definitions of AI, different approaches to AI (strong/weak, applied, cognitive), goals of AI, the history of AI, and comparisons of human and artificial intelligence. Specifically:
1) AI is defined as the science and engineering of making intelligent machines, and involves building systems that think and act rationally.
2) The main approaches to AI are strong/weak, applied, and cognitive AI. Strong AI aims to build human-level intelligence while weak AI focuses on specific tasks.
3) The goals of AI include replicating human intelligence, solving complex problems, and enhancing human-computer interaction.
4) The history of AI
This presentation discusses system calls and provides an overview of their key aspects:
System calls provide an interface between processes and the operating system. They allow programs to request services from the OS like reading/writing files. There are different methods of passing parameters to the OS, such as via registers, parameter blocks, or pushing to the stack. System calls fall into categories including process control, file management, device management, information maintenance, and communication. An example is given of how system calls would be used in a program to copy data between two files.
IRJET- Survey Paper on Human Following RobotIRJET Journal
The document summarizes research on developing an autonomous human following robot. It discusses using triangulation of radio signals from a tag worn by a human to calculate the tag's location using multiple antennas on the robot. The robot would use triangulation and received signal strength to determine the tag's position and direction to follow the human. It reviews several localization algorithms and navigation techniques used in other projects. The proposed method is to use triangulation of signals from three antennas to accurately calculate the tag's position and allow the robot to autonomously follow or be remotely controlled via Bluetooth.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
The document discusses IEEE 802.11 standards for wireless LANs. It describes the formation of the IEEE 802.11 working group in 1990 to develop wireless LAN MAC and physical specifications. It then summarizes key IEEE 802.11 standards including 802.11a, 802.11b, 802.11g, 802.11n, and more recent standards. It provides an overview of IEEE 802.11 architecture including the basic service set, extended service set, and distribution system. It also discusses services provided at the MAC layer such as reliable data delivery, access control, and security.
What is Heuristics?
A heuristic is a technique that is used to solve a problem faster than the classic methods. These techniques are used to find the approximate solution of a problem when classical methods do not. Heuristics are said to be the problem-solving techniques that result in practical and quick solutions.
Heuristics are strategies that are derived from past experience with similar problems. Heuristics use practical methods and shortcuts used to produce the solutions that may or may not be optimal, but those solutions are sufficient in a given limited timeframe.
History
Psychologists Daniel Kahneman and Amos Tversky have developed the study of Heuristics in human decision-making in the 1970s and 1980s. However, this concept was first introduced by the Nobel Laureate Herbert A. Simon, whose primary object of research was problem-solving.
Why do we need heuristics?
Heuristics are used in situations in which there is the requirement of a short-term solution. On facing complex situations with limited resources and time, Heuristics can help the companies to make quick decisions by shortcuts and approximated calculations. Most of the heuristic methods involve mental shortcuts to make decisions on past experiences.
Heuristic techniques
The heuristic method might not always provide us the finest solution, but it is assured that it helps us find a good solution in a reasonable time.
Based on context, there can be different heuristic methods that correlate with the problem's scope. The most common heuristic methods are - trial and error, guesswork, the process of elimination, historical data analysis. These methods involve simply available information that is not particular to the problem but is most appropriate. They can include representative, affect, and availability heuristics.
We can perform the Heuristic techniques into two categories:
Direct Heuristic Search techniques in AI
It includes Blind Search, Uninformed Search, and Blind control strategy. These search techniques are not always possible as they require much memory and time. These techniques search the complete space for a solution and use the arbitrary ordering of operations.
The examples of Direct Heuristic search techniques include Breadth-First Search (BFS) and Depth First Search (DFS).
Weak Heuristic Search techniques in AI
It includes Informed Search, Heuristic Search, and Heuristic control strategy. These techniques are helpful when they are applied properly to the right types of tasks. They usually require domain-specific information.
The examples of Weak Heuristic search techniques include Best First Search (BFS) and A*.
About Naming Concepts in Distributed systems.
More about its services, its types & the approaches of implementation for Name Space & Name Resolution and Locating Entities Approaches with example diagrams.
This document discusses synchronization in mobile computing systems. It describes how data is replicated and distributed across mobile devices, personal computers, and remote servers. It then discusses various synchronization techniques used to maintain consistency between distributed copies of data, including one-way synchronization initiated by the server or client, two-way synchronization, and refresh synchronization. The document also covers domain-specific rules that govern how data is synchronized across different platforms and data formats.
Cluster analysis is an unsupervised machine learning technique that groups similar data objects into clusters. It finds internal structures within unlabeled data by partitioning it into groups based on similarity. Some key applications of cluster analysis include market segmentation, document classification, and identifying subtypes of diseases. The quality of clusters depends on both the similarity measure used and how well objects are grouped within each cluster versus across clusters.
The document discusses the UMTS Terrestrial Radio Access Network (UTRAN) which connects mobile devices to telephone networks and the internet. It contains Node B base stations and Radio Network Controllers that make up the radio access network. There are physical, transport, and logical channels that deal with different information flows and tasks between the network and terminals. The document outlines the lu, Uu, lub, and lur interfaces that connect internally and externally to other network entities like the core network and between RNCs and Node Bs. It notes that high uplink data transmission speed from the UE to base stations is important for high connectivity speeds compared to downlink transmission speed from base stations to the UE.
There are 5 levels of virtualization implementation:
1. Instruction Set Architecture Level which uses emulation to run inherited code on different hardware.
2. Hardware Abstraction Level which uses a hypervisor to virtualize hardware components and allow multiple users to use the same hardware simultaneously.
3. Operating System Level which creates an isolated container on the physical server that functions like a virtual server.
4. Library Level which uses API hooks to control communication between applications and the system.
5. Application Level which virtualizes only a single application rather than an entire platform.
Fault tolerance is important for distributed systems to continue functioning in the event of partial failures. There are several phases to achieving fault tolerance: fault detection, diagnosis, evidence generation, assessment, and recovery. Common techniques include replication, where multiple copies of data are stored at different sites to increase availability if one site fails, and check pointing, where a system's state is periodically saved to stable storage so the system can be restored to a previous consistent state if a failure occurs. Both techniques have limitations around managing consistency with replication and overhead from checkpointing communications and storage requirements.
Problem solving
Problem formulation
Search Techniques for Artificial Intelligence
Classification of AI searching Strategies
What is Search strategy ?
Defining a Search Problem
State Space Graph versus Search Trees
Graph vs. Tree
Problem Solving by Search
This document discusses asynchronous data transfer between independent units. It describes two methods for asynchronous transfer - strobe control and handshaking. Strobe control uses a single control line to time each transfer, while handshaking introduces a second control signal to provide confirmation between units. Specifically, it details the handshaking process, which involves control signals like "data valid" and "data accepted" or "ready for data" to coordinate placing data on the bus and accepting data between a source and destination unit.
The document discusses search strategies in artificial intelligence. It defines key terms like search space, start state, goal test, and search tree. It describes properties of search algorithms like completeness, optimality, time complexity, and space complexity. It differentiates between uninformed searches, which do not use domain knowledge, like breadth-first search and depth-first search, and informed searches, which use heuristics to guide the search more efficiently, like greedy search and A* search. The document outlines the differences between informed and uninformed searches.
The document discusses different distribution design alternatives for tables in a distributed database management system (DDBMS), including non-replicated and non-fragmented, fully replicated, partially replicated, fragmented, and mixed. It describes each alternative and discusses when each would be most suitable. The document also covers data replication, advantages and disadvantages of replication, and different replication techniques. Finally, it discusses fragmentation, the different types of fragmentation, and advantages and disadvantages of fragmentation.
The document provides an overview of GSM architecture including:
1. GSM uses a cellular network architecture with base stations, base station controllers, mobile switching centers, and databases to manage subscriber identity and location.
2. The network allows for voice calls and data services including SMS, and provides security through subscriber authentication and encryption.
3. GSM is a global standard that enabled international roaming and continues to evolve to support higher data rates through technologies like GPRS, EDGE, and WCDMA.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
The document discusses various protocols and approaches for improving the performance of TCP over wireless networks. It notes that wireless networks have higher bit error rates, lower bandwidth, and mobility issues compared to wired networks. Several protocols are described that aim to distinguish wireless losses from congestion losses to avoid unnecessary TCP reactions:
- Indirect TCP splits the connection and handles losses locally at the base station. Snoop caches packets at the base station for retransmission.
- Mobile TCP further splits the connection and has the base station defer acknowledgments. It can also inform the sender about handoffs versus interface switches.
- Multiple acknowledgments uses two types of ACKs to isolate the wireless and wired portions of the network.
-
1. Planning involves finding a sequence of actions that achieves a goal starting from an initial state. It uses a set of operators that define the possible actions and their effects.
2. A plan is a sequence of operator instances that transforms the initial state into a goal state. Classical planning assumes fully observable, deterministic environments.
3. Planning problems can be represented using a logical language that describes states, goals, actions and their preconditions and effects. This representation allows planning algorithms to operate over problems.
In the field of artificial intelligence (AI), planning refers to the process of developing a sequence of actions or steps that an intelligent agent should take to achieve a specific goal or solve a particular problem. AI planning is a fundamental component of many AI systems and has applications in various domains, including robotics, autonomous systems, scheduling, logistics, and more. Here are some key aspects of planning in AI:
Definition of Planning: Planning involves defining a problem, specifying the initial state, setting a goal state, and finding a sequence of actions or a plan that transforms the initial state into the desired goal state while adhering to certain constraints.
State-Space Representation: In AI planning, the problem is often represented as a state-space, where each state represents a snapshot of the system, and actions transform one state into another. The goal is to find a path through this state-space from the initial state to the goal state.
Search Algorithms: AI planning typically relies on search algorithms to explore the state-space efficiently. Uninformed search algorithms, such as depth-first search and breadth-first search, can be used, as well as informed search algorithms, like A* search, which incorporates heuristics to guide the search.
Heuristics: Heuristics are used in planning to estimate the cost or distance from a state to the goal. Heuristic functions help inform the search algorithms by providing an estimate of how close a state is to the solution. Good heuristics can significantly improve the efficiency of the search.
Plan Execution: Once a plan is generated, the next step is plan execution, where the agent carries out the actions in the plan to achieve the desired goal. This often requires monitoring the environment to ensure that the actions are executed as planned.
Temporal and Hierarchical Planning: In more complex scenarios, temporal planning deals with actions that have temporal constraints, and hierarchical planning involves creating plans at multiple levels of abstraction, making planning more manageable in complex domains.
Partial and Incremental Planning: Sometimes, it may not be necessary to create a complete plan from scratch. Partial and incremental planning allows agents to adapt and modify existing plans to respond to changing circumstances.
Applications: Planning is used in a wide range of applications, from manufacturing and logistics (e.g., scheduling production and delivery) to robotics (e.g., path planning for robots) and game playing (e.g., chess and video games).
Challenges: Challenges in AI planning include dealing with large search spaces, handling uncertainty, addressing resource constraints, and optimizing plans for efficiency and performance.
AI planning is a critical component in creating intelligent systems that can autonomously make decisions and solve complex problems.
Client-Centric Consistency
Provide guarantees about ordering of operations only for a single client, i.e.
Effects of an operations depend on the client performing it
Effects also depend on the history of client’s operations
Applied only when requested by the client
No guarantees concerning concurrent accesses by different clients
Assumption:
Clients can access different replicas, e.g. mobile users
This document provides an overview of artificial intelligence (AI) including definitions of AI, different approaches to AI (strong/weak, applied, cognitive), goals of AI, the history of AI, and comparisons of human and artificial intelligence. Specifically:
1) AI is defined as the science and engineering of making intelligent machines, and involves building systems that think and act rationally.
2) The main approaches to AI are strong/weak, applied, and cognitive AI. Strong AI aims to build human-level intelligence while weak AI focuses on specific tasks.
3) The goals of AI include replicating human intelligence, solving complex problems, and enhancing human-computer interaction.
4) The history of AI
This presentation discusses system calls and provides an overview of their key aspects:
System calls provide an interface between processes and the operating system. They allow programs to request services from the OS like reading/writing files. There are different methods of passing parameters to the OS, such as via registers, parameter blocks, or pushing to the stack. System calls fall into categories including process control, file management, device management, information maintenance, and communication. An example is given of how system calls would be used in a program to copy data between two files.
IRJET- Survey Paper on Human Following RobotIRJET Journal
The document summarizes research on developing an autonomous human following robot. It discusses using triangulation of radio signals from a tag worn by a human to calculate the tag's location using multiple antennas on the robot. The robot would use triangulation and received signal strength to determine the tag's position and direction to follow the human. It reviews several localization algorithms and navigation techniques used in other projects. The proposed method is to use triangulation of signals from three antennas to accurately calculate the tag's position and allow the robot to autonomously follow or be remotely controlled via Bluetooth.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
A Comparative Study on Profile Based Location Management for Personal Communi...IJERA Editor
Location of the mobile user is registered to the two databases for call tracking and those registration processes
basis much network traffic. By this speed of Call delivery reduced and location updating cost improved. In this
paper, the first method a new meek location management by registering Representative VLR of group of certain
VLRs regionally and broadcasting for searching a mobile user, so called rVLR-B.This The representative VLR
of several VLRs and register mobile users’ location. When set up the call path between mobile users, the VLR
of the caller inquiries callee’s rVLR for searching the location of callee instead of demanding to VLR of callee.
And then rVLR broadcast the callee’s location to all VLR of the region simultaneously. Location registration is
only performed when a mobile user visits a new rVLR network area from present area. Using the rVLR-B, the
cost of maintaining location of mobile users was abridged. The second technique for reducing the costs during
the location tracking and location update is proposed. Taking the regular movement pattern of the users it
produces the block and the user registers with the HLR only after crossing the block instead of crossing the
single cell. The block register (BR) is introduced between the block and the HLR in two level systems to
preserve the blocks, thus creates three level architecture. In this architecture some signaling cost values between
the MSC-BR, BRHLR and BR-BR are maintained to get the better enactment. By the rVLR-B and BR the
performance of speed of call delivery improved and location updation will be diminished
A Comparative Study on Profile Based Location Management for Personal Communi...IJERA Editor
Location of the mobile user is registered to the two databases for call tracking and those registration processes basis much network traffic. By this speed of Call delivery reduced and location updating cost improved. In this paper, the first method a new meek location management by registering Representative VLR of group of certain VLRs regionally and broadcasting for searching a mobile user, so called rVLR-B.This The representative VLR of several VLRs and register mobile users’ location. When set up the call path between mobile users, the VLR of the caller inquiries callee’s rVLR for searching the location of callee instead of demanding to VLR of callee. And then rVLR broadcast the callee’s location to all VLR of the region simultaneously. Location registration is only performed when a mobile user visits a new rVLR network area from present area. Using the rVLR-B, the cost of maintaining location of mobile users was abridged. The second technique for reducing the costs during the location tracking and location update is proposed. Taking the regular movement pattern of the users it produces the block and the user registers with the HLR only after crossing the block instead of crossing the single cell. The block register (BR) is introduced between the block and the HLR in two level systems to preserve the blocks, thus creates three level architecture. In this architecture some signaling cost values between the MSC-BR, BRHLR and BR-BR are maintained to get the better enactment. By the rVLR-B and BR the performance of speed of call delivery improved and location updation will be diminished. Keywords: Home Location Register, Visitor Location Register, Mobile Switching Center, Base Station, Block Register, Mobile Station, r-VLR- Representative VLR
Location Fingerprinting is a very familiar Wi-Fi positioning method, which determines a device by retrieving the information recorded containing the location fingerprint. These methods deploy the signal strength (RSS) to predict the coordinate. There are feedbacks for using the absolute RSS either the absolute RSS in a time interval may not be representable of the IEEE 802.11 signal, as the signal may fluctuate or a manual error prone calibration is needed across different mobile platform. The main target is to propose the use of Fourier descriptors in LF. We convert the IEEE 802.11b Wi-Fi signal into a Fourier domain. Then, the Fourier descriptors are used to predict the location by applying the K-Nearest Neighbor algorithm. The results show that the effectiveness of LF methods based on Fourier descriptors lead to substantially more accurate and robust localization.
SELECTING VOTES FOR ENERGY EFFICIENCY IN PROBABILISTIC VOTING-BASED FILTERING...ijasa
Wireless sensor networks are easily compromised by an adversary, such as fabricated with false votes attacks and false votes on real reports attacks. These attacks generate false data to drain the energy resource of sensors and interrupt the inflow of a real report. PVFS was proposed to detect them by verifying votes in the real report. When a real event occurs, a cluster head collects all of the votes from its neighboring nodes and selects the votes up to a defined number of votes. In this paper, our proposed method decides the number of votes based on a fuzzy rule-based system to improve energy savings as compared to PVFS. We evaluated the effectiveness of the proposal as two attacks occur simultaneously in the sensor network. The experimental results show that our method saves energy resources and maintains the security level against these multiple attacks
1. The document discusses 1xEV-DO hard handoff, which involves handing off a mobile device's connection between base stations or access networks in a 1xEV-DO network.
2. A 1xEV-DO hard handoff can occur between base stations within the same radio node controller (RNC), between RNCs served by the same packet data serving node (PDSN), or between PDSNs.
3. The key aspects of a 1xEV-DO hard handoff are the registration of a new access network session on the target network, and establishment of a new R-P session between the target RNC and PDSN while maintaining the existing PPP connection between
The document discusses 1xEV-DO hard handoff which allows a mobile to transfer an active data session between base stations or access networks with minimal disruption. It describes the 1xEV-DO network architecture and call flow, and covers different types of hard handoffs including intra-RNC, inter-RNC/intra-PDSN, inter-RNC/inter-PDSN, 1xEV-DO to 1xRTT, and 1xRTT to 1xEV-DO. For inter-network handoffs, the PPP session and IP address may be maintained using mobile IP, otherwise a new PPP session and IP address will be established.
Nuzzer algorithm based Human Tracking and Security System for Device-Free Pas...Eswar Publications
In recent years, majority of researches are focused on localization system for wireless environment. These researches rely on localization using devices to track the entities. In this paper, we use, a recently proposed Device-free Passive (DfP) that uses Probabilistic techniques to track locations in large-scale real environment without the need of carrying devices. The proposed system uses the Access Points (APs) and Monitoring Point (MPs) that works by monitoring and processing the changes in the received physical signals at one or more monitoring points to detect changes in the environment. The system uses continuous space estimator to return multiple location while the mortal is in motion. Our results show that the system can achieve very high probability of detection and tracking with very few false positives.
Presentation used at Mobile Ghent 2013 for the paper ""Mobility collector: Battery Conscious Mobile Tracking"
Paper link: http://www.tandfonline.com/doi/full/10.1080/17489725.2014.973917
Cellular wireless networks use three basic devices: a mobile station, base transceiver, and mobile switching office. The base transceiver includes an antenna and controller. The switching office connects calls between mobile units. Two channel types are available: control channels for call setup/maintenance, and traffic channels that carry voice/data. Cells use low-powered transmitters and each cell has its own antenna and base station. Frequency reuse allows the same frequencies to be used in different cells. As users move between cells, handoffs change their assignment from one base station to another.
Performance of Various Mobile IP Protocols and Security ConsiderationsCSCJournals
This document discusses and compares different mobile IP protocols. It presents an analytic model to evaluate the performance of Mobile IP (MIP), Hierarchical Mobile IP (HMIP), and Dynamic HMIP (DHMIP) based on mean signaling delay and bandwidth per call under different types of mobile terminal mobility. The model divides call holding time into small time intervals and calculates bandwidth used in each interval, accounting for both data bandwidth and signaling bandwidth during handoffs. The analysis finds that HMIP outperforms MIP and DHMIP in most cases studied due to its ability to localize registration processes and reduce signaling burden through a hierarchy of foreign agents and gateway agents.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Remote sensing satellite data demodulation and bit synchronization 2IAEME Publication
This document discusses the design and implementation of a high data rate digital demodulator for receiving data from remote sensing satellites. It describes the key components of the demodulator, including an IF band pass filter, automatic gain control amplifier, analog-to-digital converter, and digital signal processing algorithms for carrier recovery and symbol detection. The performance of the demodulator is evaluated using MATLAB simulations. The goal is to achieve a bit error rate of 10-6 or better, within 2 dB of theoretical values.
Researchpaper a survey-on-de-registration-schemes-in-pcs-networkRajeev Ranjan
This document summarizes various de-registration schemes used in personal communication networks to reduce signaling traffic from location updates. When a mobile terminal changes registration areas and moves from one visitor location register to another, its entry must be removed from the previous register to avoid stale location data. Common de-registration schemes discussed include explicit de-registration controlled by the home location register, implicit de-registration that does not remove entries, polling schemes that periodically check for mobiles that have left an area, timeout schemes where mobiles periodically re-register, movement-based schemes with thresholds on cell crossings, distance-based schemes with distance thresholds, and group de-registration where the home location register maintains a list of mobiles that have left an area
The document describes the key components of basic cellular systems including circuit-switched and packet-switched systems. It discusses two types of circuit-switched systems: analog and digital. The main components of an analog system are mobile units, cell sites, and a mobile telephone switching office. A digital system consists of mobile stations, base transceiver stations, base station controllers, and switching subsystems. It also outlines the main elements of a packet-switched cellular network and discusses performance criteria such as voice quality, data quality, coverage, and special features.
The document discusses the key components of basic cellular systems including circuit-switched and packet-switched systems. It describes the main elements of analog circuit-switched systems including mobile units, cell sites, and mobile telephone switching offices. For digital circuit-switched systems, it outlines the mobile station, base transceiver station, base station controller, and switching subsystems. It also summarizes the mobile station, radio network controller, support nodes, and gateway for packet-switched systems and reviews performance criteria such as voice quality, data quality, coverage, and special features.
Crowd control system using ir transmitter and receivereSAT Journals
Abstract An efficient crowd control system is needed for safety of lives, property, time and economy. Crowd control system presents a design and implementation of low cost, low power consummated and more reliable and an infrared based intelligent crowd control system. The system contains Infrared transmitters and receiver. The basic concept of IR (Infrared) obstacle detection is to transmit the IR signal (radiation) in a direction and signal is received at the IR receiver when the IR radiation bounces back from a surface of the object. The system can response rapidly with violation of crowd limit. System describes highly accurate crowd control system using infrared communication. Proposed system achieves high accuracy and more efficiency at four way terminals. In every direction the road will consist of an IR transmitter-receiver pair at a certain distance. When crowd will be heavy in one particular direction during emergency situation it will indicate the administrator by sending message. So the heavy crowd can be routed to other route by preventing the stampede. Keywords: Crowd, IR transmitter, IR receiver, Stampede
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Unit IV Knowledge and Hybrid Recommendation System.pdfArthyR3
This document details the knowledge based recommendation system and hybrid recommendation system. A knowledge and hybrid recommendation system combines the capabilities of knowledge-based and hybrid recommendation systems to provide personalized recommendations to users.
This tutorial provides an overview of content-based recommender systems, a type of recommendation system that suggests items based on the features of the items and a profile of the user's preferences. It covers the basic concepts, algorithms, and implementation steps involved in building a content-based recommender system.
This is a quick reference document that comprises the entire concepts of Java Programming. This document covers, the basic of OOPs, features of Java, basics of Java, Inheritance, Interface, Exception, Generic, Stream, Collection, Multithreading, Swings, etc.
This document discusses middleware in Express.js web application frameworks. It defines middleware as functions that have access to the request and response objects and can perform tasks like executing code, modifying requests and responses, ending the request-response cycle, or calling the next middleware function. The document then provides examples of different types of middleware like application-level middleware, router-level middleware, error-handling middleware, and built-in middleware from Express. It explains how middleware can be used for tasks like request processing, response handling, authentication, authorization, static file serving, logging, and routing. It also covers using middleware with routes, cookies, sessions, and other concepts in Express.
This document provides an overview of AngularJS concepts covered in Unit II of the course IT2304 – Full Stack Web Development, including modules and dependency injection, scopes, directives, filters, and services. It defines modules, controllers, dependencies, scopes, common directives like ng-repeat and ng-if, filters like currency and date, and services like $http, $timeout, and custom services. Example code is provided to demonstrate key concepts.
This document provides a cheat sheet for jQuery selectors, effects, and events covered in Unit I of the Full Stack Web Development course IT2304. It includes over 30 categories of selectors with examples, 17 methods for effects like hide/show, fade, and slide, and over 20 event methods like click, change, and resize. The document also covers 10 jQuery utility methods such as trim, each, and inArray.
This document discusses the syllabus for the course IT1301 - Object Oriented Programming. It covers key concepts in OOP like classes, objects, inheritance, polymorphism, abstraction and encapsulation. It also discusses features of Java like being platform independent, secure, robust etc. The document contains examples and questions related to OOP concepts in Java. Constructors and their types, access specifiers, object class and reflection are explained in detail with examples. Creation and accessing of user-defined packages in Java is also discussed.
This document discusses electronic mail security and web security. It covers Pretty Good Privacy (PGP) and S/MIME for securing email, describing their encryption, authentication, and key management functions. For web security, it outlines threats like eavesdropping, impersonation, and denial of service attacks. It also explains how Secure Sockets Layer (SSL) and Transport Layer Security (TLS) establish encrypted connections between web browsers and servers to protect data confidentiality and integrity during transmission. Cryptographic algorithms like SHA-1, MD5, DES, and RSA are used to authenticate, encrypt, and digitally sign messages.
The document discusses intrusion detection and various types of intruders and intrusion techniques. It covers password capture methods like watching someone enter their password or using a Trojan horse. It also discusses different types of intrusion detection approaches like statistical anomaly detection, rule-based detection, and honeypots. The document then covers password management, viruses, worms, and distributed denial of service attacks. It concludes by discussing firewall design principles and characteristics like packet filtering routers.
This material covers Authentication requirement, Authentication function, MAC, Hash function, Security of hash function and MAC, SHA, Digital signature and authentication protocols, DSS, Authentication protocols like Kerberos and X.509, entity authentication
This document provides an overview of message authentication and integrity. It discusses the need for authentication in network security and outlines different authentication functions including message encryption, message authentication codes (MACs), and hash functions. It describes how MACs are generated using a secret key and message and provides the requirements for MACs. The document also discusses the MD5 and SHA hash algorithms, explaining their processes and analyzing their security strengths and weaknesses.
This document is to guide in the basic topics of cryptographic and network security. The detail insight of classical encryption algorithm is given here. The step by step process is clearly explained in this document.
JAVA - A Quick Reference
A quick guide to learn more about JAVA Programming. This covers the core concepts of JAVA with OOP concepts. This also covers swing programming.
Cs8792 cns - Public key cryptosystem (Unit III)ArthyR3
This document provides an overview of public key cryptography and asymmetric key ciphers. It begins with the underlying mathematics including primes, primality testing, factorization, Euler's totient function, Fermat's theorem, and exponentiation. It then discusses asymmetric key ciphers like RSA and Diffie-Hellman key exchange. RSA is described in more detail, including how public and private key pairs are generated using large prime numbers and exponentiation modulo a composite integer. Security relies on the difficulty of factoring large numbers.
This document is a worksheet for a cryptography and network security course. It contains definitions of key terms like cryptography, encryption, decryption, and types of attacks. It also outlines classical encryption techniques like the Caesar cipher, Playfair cipher, Hill cipher, Vigenere cipher, and transposition techniques. Finally, it covers number theory topics such as prime numbers, factorization, Fermat's theorem, Euler's theorem, and primitive roots as they relate to cryptography.
This document discusses message authentication and hash functions. It begins by defining message authentication and its security requirements. It then describes three approaches to message authentication: message encryption, message authentication codes (MACs), and hash functions. It provides details on how MACs and hash functions work, including properties and requirements. Specific algorithms like MD5 are also covered. The document aims to explain the concepts and tradeoffs between different message authentication techniques.
This document contains a question bank for the subject Cryptography and Network Security. It includes questions grouped under different units of the subject: Introduction and Number Theory, Block Ciphers and Public Key Cryptography, Hash Functions and Digital Signatures. For each question, it provides the question number, question, marks allotted, knowledge level and number of times the question may appear in the assessment. The document also provides details of the subject code, name, class, staff in-charge and course code.
The document outlines the objectives, topics, and learning outcomes of the CS6660 Compiler Design course. The course aims to teach students about compiler design principles, parsing techniques, translation processes, optimization methods, and code generation. It is divided into 5 units that cover introduction to compilers, lexical analysis, syntax analysis, syntax directed translation and runtime environment, and code optimization and generation. At the end of the course, students should be able to design and implement a prototype compiler, apply optimization techniques, use compiler construction tools, and understand the different levels of translation.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Accident detection system project report.pdfKamal Acharya
The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Software Engineering and Project Management - Software Testing + Agile Method...Prakhyath Rai
Software Testing: A Strategic Approach to Software Testing, Strategic Issues, Test Strategies for Conventional Software, Test Strategies for Object -Oriented Software, Validation Testing, System Testing, The Art of Debugging.
Agile Methodology: Before Agile – Waterfall, Agile Development.
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Transcat
Join us for this solutions-based webinar on the tools and techniques for commissioning and maintaining PV Systems. In this session, we'll review the process of building and maintaining a solar array, starting with installation and commissioning, then reviewing operations and maintenance of the system. This course will review insulation resistance testing, I-V curve testing, earth-bond continuity, ground resistance testing, performance tests, visual inspections, ground and arc fault testing procedures, and power quality analysis.
Fluke Solar Application Specialist Will White is presenting on this engaging topic:
Will has worked in the renewable energy industry since 2005, first as an installer for a small east coast solar integrator before adding sales, design, and project management to his skillset. In 2022, Will joined Fluke as a solar application specialist, where he supports their renewable energy testing equipment like IV-curve tracers, electrical meters, and thermal imaging cameras. Experienced in wind power, solar thermal, energy storage, and all scales of PV, Will has primarily focused on residential and small commercial systems. He is passionate about implementing high-quality, code-compliant installation techniques.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
Home security is of paramount importance in today's world, where we rely more on technology, home
security is crucial. Using technology to make homes safer and easier to control from anywhere is
important. Home security is important for the occupant’s safety. In this paper, we came up with a low cost,
AI based model home security system. The system has a user-friendly interface, allowing users to start
model training and face detection with simple keyboard commands. Our goal is to introduce an innovative
home security system using facial recognition technology. Unlike traditional systems, this system trains
and saves images of friends and family members. The system scans this folder to recognize familiar faces
and provides real-time monitoring. If an unfamiliar face is detected, it promptly sends an email alert,
ensuring a proactive response to potential security threats.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
2. 4.1.1 Location Management
The location of the mobile unit is
recorded to HLR and VLR
Mobility Management has two main
task:
Location Management
Handoff Management
Prepared by R. Arthy, AP/IT
3. I Introduction to Location Management
Objective:
To minimize the communication overhead due to database
updates
Three tasks:
Location Lookup
Location Update
Paging
Cost of update and paging increases as the cell size
increases
Solution: Location area and paging areas
Prepared by R. Arthy, AP/IT
4. (contd…)
Three modes that the mobile node can
operate
Active mode
Doze mode
Power down mode
Prepared by R. Arthy, AP/IT
6. Steps
1. The caller dials a number. To find the location of the called number, the
caller unit sends a location query to its base station source base station
2. The source base station sends the query to the S – LS fro location
delivery
3. S – LS first looks up the VLR to find the location.
4. IF VLR search fails, then the location query is sent to the HLR
5. HLR finds the location of D – LS
6. The search goes to D – LS
7. D – LS finds the address of D – BS
8. Address of D – BS is sent to be HLR
9. HLR sends the address of D – BS to S – LS
10. The address of D – BS is sent to the source base station, which sets up
the communication session
Prepared by R. Arthy, AP/IT
8. Steps
1. The mobile unit moves to a new registration area which is serviced by a
new location server
2. The new base station sends the update query to new LS
3. The new LS searches the address of the HLR in its local database
4. The new location of the mobile unit is sent to HLR
5. The old location of the mobile unit is replaced by the new location
6. The HLR sends user profile and other information to new LS
7. The new LS stores the information it received from HLR
8. The new LS informs the new base station that location update has been
completed
9. The HLR also sends a message about this location update to the old LS.
The old LS deletes the old location information
10. The old LS sends a confirmation message to the HLRPrepared by R. Arthy, AP/IT
9. III.1 Forward Pointer Location
Management Scheme
Objective:
To minimize network overhead due to HLR
updates
The pointer at the previous location of the
mobile unit which points to its current location
The pointer is a descriptor which stores mobile
unit identity and its current location.
The revisit to a registration area creates a
transient loop
Prepared by R. Arthy, AP/IT
11. III.1.a Updates using Forward
Pointers
When MU2 leaves the R1 and moves to R2
then,
The user profile and the number of forward
pointers created so far by MU2 is transferred
from R1 to R2
A forward pointer is created at R1 which points to
R2
This forward pointer can be stored in any of
the BS
Prepared by R. Arthy, AP/IT
12. (contd…)
Heuristic based update approach
Number of pointers created
Number of search requests
Based on constant update time
Prepared by R. Arthy, AP/IT
14. Steps
The caller dials the number of destination user
The source base station sends the query to the source LS for location discovery
Source LS first looks up the VLR to find the location. If the called number is a
visitor to the source base station, then the location is known and the connection is
setup
If VLR search fails, then the location query is send to the HLR
The destination HLR finds the location of destination location server
The destination HLR sends the location of destination location server to the
source LS
The source LS finds the first forward pointer and traverse the chain of forward
pointer and reaches the destination server
The location of current base station is forward to the source LS
Source Ls transfers the address of current base station and the call is set up
Prepared by R. Arthy, AP/IT
15. III.1.c. Forward Pointer Maintenance
Need:
To remove pointer which have not been used for
some time
To delete dangling pointers
Ways to remove pointers:
Timestamp
Directed graph
Dangling pointer – If redundant pointers are
not removed in correct order
Prepared by R. Arthy, AP/IT
17. 4.1.2 Handoff Management
Objective:
To provide continuous connectivity
Degradation Interval
Prepared by R. Arthy, AP/IT
18. I Introduction
Types of handoff
Intra system
Inter system
Three steps
Handoff detection
Assignment of channels
Transfer of radio link
Prepared by R. Arthy, AP/IT
19. II Handoff Detection
Must properly detect genuine and false
handoff (which occurs because of signal
fading)
Three approaches
Mobile – Assisted Handoff (MAHO)
Mobile – Controlled Handoff (MCHO)
Network – Controlled Handoff (NCHO)
Prepared by R. Arthy, AP/IT
20. II.1. Mobile – Assisted Handoff
Every mobile unit continuously measures the
signal strength data from the surrounding base
station
And notifies the strength data to the serving base
station
The strength of these signals are analyzed
And a handoff is initiated, when the strength of the
neighbor BS > strength of the serving BS
Prepared by R. Arthy, AP/IT
21. II.2. Mobile – Controlled Handoff
Mobile unit is responsible for detecting a
handoff
The MU continuously monitors the signal
strength from neighboring BS and identifies
if a handoff is necessary
Prepared by R. Arthy, AP/IT
22. II.3. Network – Controlled Handoff
(NCHO)
The BS monitors the signal strength
used by MU
If it falls below a threshold value,
the BS initiates handoff
Prepared by R. Arthy, AP/IT
23. III Assignment of Channels
Objective:
To achieve a high degree of channel utilization
To minimize chances of dropping connection due to
unavailability of channel
Schemas
Nonprioritized Schema
Reserved Channel Schema
Queuing Priority Schema
Subrating Schema
Prepared by R. Arthy, AP/IT
28. IV Radio Link Transfer
Five link transfer cases for which the
handoff has to be processed
Intracell handoff
Intercell or Intra BS handoff
Inter BS handoff or Intra MSC handoff
Intersystem or Inter MSC handoff
Prepared by R. Arthy, AP/IT
35. Introduction
Continuous connectivity in mobile space
Example
In busy city traffic, carpoolers usually end up
spending a significant amount of time on the
road. Instead of waiting, they can use their mobile
gadget to connect to their corporate database
servers and begin their work. This facility will
minimize the negative effect of communication
delay on productivity
Prepared by R. Arthy, AP/IT
36. 4.2.1 Effect of mobility on the
management of data
In conventional database and distributed
database the data’s are stationary
Integration of geographical mobility will
reduce the traveling time
Prepared by R. Arthy, AP/IT
37. I Data Categorization
The data distribution in conventional
distributed database systems can be done in
three ways:
Partitioned
Partial replication
Full replication
In mobility, additionally we have Location –
Dependent Data (LDD)
Prepared by R. Arthy, AP/IT
38. Location – Dependent Data (LDD)
It is a class of data values are tightly linked to
specific geographical location
Example: city, telephone code area, ….
LID example: Social Security Number (SSN)
Two types of Query
Location Dependent Query
Location Aware Query
Prepared by R. Arthy, AP/IT
39. Location Dependent Query
For computing the result
Example: what is the distance between the
railway station to here?
where I am?
Prepared by R. Arthy, AP/IT
40. Location – Aware Query
Includes reference to a particular location
either by name or by suitable geographical
coordinates
Example: what is the distance between VNR
to MDU?
Prepared by R. Arthy, AP/IT
41. II Location Dependent Data
Distribution
Data Partitioning
Prepared by R. Arthy, AP/IT
42. Data Region
A data region is a geographical region or a
geographical cell and every geographical
point of this region satisfies 1:1 mapping with
data
Example:
Hotel chain – same hotel different branch –
different cost
Prepared by R. Arthy, AP/IT
44. Effect of Mobility in Atomicity
Guarantees that partial results of a
transaction do not exist in the database
Logging approach is not used – several
server is available
Prepared by R. Arthy, AP/IT
45. Effect of Mobility on Consistency
Only one correct value for each data object
Mutual consistency – indicates that all values
of the same data item converge to this one
correct value
Prepared by R. Arthy, AP/IT
46. Effect of Mobility on Isolation
Ensures that a transaction does not interfere
with the execution of another transaction
Fragmentation – ensure isolation
Data regions – ensure isolation
Prepared by R. Arthy, AP/IT
47. Effect of Mobility on Durability
Guarantees the persistence of
committed data items in the DB
Prepared by R. Arthy, AP/IT
48. Effect of Mobility on Commit
Location Commit – binds a transaction
commit to a region
Example:
Reserve 5 seats in a vegetarian restaurant located
1 mile from here
Prepared by R. Arthy, AP/IT
49. Effect of Connectivity on
Transaction Processing
Continuously Connected mode
Disconnected mode
Intermittent Connected mode
Prepared by R. Arthy, AP/IT
51. 4.3.1 Mobile Database System
It provides full database and mobile
communication functionalities
It allows a mobile user to initiate transactions
from anywhere and of anytime
It guarantees their consistency preserving
execution
It guarantees database recovery
Prepared by R. Arthy, AP/IT
52. I Properties
Geographical Mobility
Connection and Disconnection
Data Processing Capability
Wireless communication
Transparency
Scalability
Prepared by R. Arthy, AP/IT
55. III Transaction Execution in MDS
Parallel processing – to improve system
performance
Leads to fragmenting a transaction
Coordinator – manages the set of activities
3 main ways to implement a coordinator
Centralized
Partially replicated
Totally replicated
Prepared by R. Arthy, AP/IT
56. Identification of Coordinator in MDS
A coordinator must have:
Direct and continuous communication with other
nodes
Theoretically unlimited and continuous power
and large storage space
High reliability and availability
Prepared by R. Arthy, AP/IT
57. Transaction Processing in MDS
A transaction in MDS can be initiated from a
DBS or from a MU or from both
When there are more than one nodes involved
in the execution, then the following situation
may arise:
Origin at MU
Origin at DBS
Prepared by R. Arthy, AP/IT
58. (contd…)
Local execution (MU) – if it cannot be executed at
MU, then there are two option:
Transfer required data items from DBS to MU
Distribute transaction to a set of nodes
Mobility of MU is difficulty task for a coordinator
which requires coordinating and movement of the
MU correctly
With mobility the following scenarios are possible:
MU does not move
MU moves
Distributed processing and MU moves
Prepared by R. Arthy, AP/IT
59. (contd…)
Link can be maintained in two ways:
Static method
Dynamic method
Prepared by R. Arthy, AP/IT
60. IV Need for Mobile Transaction
Model
Handoff
The presence of doze mode, disconnected
mode, forced disconnection
Lack of necessary resources – memory &
wireless channel
Presence of location data
Prepared by R. Arthy, AP/IT
61. Execution Model Based on ACID
Transaction Framework
A transaction is a collection of operations on the
physical and abstract application state
Geographic Domain:
The Geographic Domain, G, is the total geographical area
covered by all mobile units of a cellular system
G = (C1+C2+C3+….+Cn), Ci – area of the cell
Location:
A location is a premise point within the Geographical
Domain.
It represents the smallest identifiable position in the
domain.
Each location is identified by a specific id, L
G=Union(L)
Prepared by R. Arthy, AP/IT
62. Mobile Transaction Model
HiCoMo: High Commit Mobile Transaction
Model
Moflex Transaction Model
Kangaroo Mobile Transaction Model
MDSTPM Transaction Execution Model
Mobilaction – A Mobile Transaction Model
Prepared by R. Arthy, AP/IT
63. HiCoMo: High Commit Mobile
Transaction Model
It is mobile transaction execution model
It is mainly for processing aggregate data
stored in a data warehouse which resides in
mobile units
It is always initiated on mobile units
They are processed in a disconnection mode
The results of these transactions are then
installed in the database upon reconnection
Prepared by R. Arthy, AP/IT
64. (contd…)
The base database resides on the fixed
network
It is manipulated by transactions called base
or source transactions
These transactions are initiated at the fixed
network
The transaction which is initiated at mobile
units are called HiCoMo
Prepared by R. Arthy, AP/IT
65. (contd…)
It is based on the following assumptions:
The data warehouse stores aggregate data of the
following types: average, sum, minimum and
maximum
Operations such as subtraction, addition and
multiplication are allowed with some constraints
on their order of application
The model allows some margin of errors
Prepared by R. Arthy, AP/IT
66. (contd…)
The structure of HiCoMo transaction is
based on nested transaction model
Consistency is satisfied through
convergence criteria
when the states of the base database and
the data warehouse in mobile units are
identical
Prepared by R. Arthy, AP/IT
67. (contd…)
Transaction Transformation Function
Converts install updates by source transaction.
Working:
Conflict Detection
Base Transaction Generation
Alternates Base Transaction Generation
Prepared by R. Arthy, AP/IT
68. Moflex Transaction Model
It is based on a flexible transaction model
7 components
T = {M, S, F, D, H, J, G}
M = {t1, t2, …, tn}
S = set of success dependencies between ti and tj
F = set of failure dependencies
D = set of external dependencies
H = set of handoff control rules
J = set of acceptable join rules
G = set of all acceptable states of T
Prepared by R. Arthy, AP/IT
69. (contd…)
A moflex transaction can be
Not submitted for execution - N
Currently under execution – E
Successfully completed – S
Failed - F
An execution of T is regarded as being
complete if its current state exists in set G
When this satisfied, then T can commit else
can abort
Prepared by R. Arthy, AP/IT
71. Kangaroo Mobile Transaction Model
It captures both data and the movement of
mobile units
It is based on split transaction model
Joey Transaction
Compensating or split mode
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72. (contd…)
A KT is initiated by a mobile unit is assigned
with a unique identity
The initial BS immediately creates a JT with
a UID and becomes responsible for execution
If handoff – KT is split into two transaction
(JT1, JT2)
JTs are executed in sequential
Prepared by R. Arthy, AP/IT
73. MDSTPM Transaction Model
Multi database Transaction Processing
Manager (MDTPM)
It supports transaction initiation from mobile
unit
Uses messaging and queue facilities to
establish necessary communication
Prepared by R. Arthy, AP/IT
74. (contd…)
Components:
Global Communication Manage (GCM)
Global Transaction Manager (GTM)
Local Transaction Manager (LTM)
Global Recovery Manager (GRM)
Global Interface Manager (GIM)
Prepared by R. Arthy, AP/IT
75. Mobilaction
It is capable of processing location –
dependent data in the presence of spatial
replication
It is composed of a set of sub transactions –
Execution Fragments
To manage location – based processing, a
new fundamental property called “location
(L)” – it is managed by a location mapping
function
Prepared by R. Arthy, AP/IT
77. 4.4.1 Introduction
Need for Concurrency control mechanism
Data Sharing
Serializing
Two – phase locking protocol
Approaches
Locking
Nonlocking
Prepared by R. Arthy, AP/IT
78. Ways of Locking Data Items
Locking protocol supports two basic operations:
Locking
Unlocking
Two phases:
Growing phase
Shrinking phase
Three phase for managing two – phase locking
Locking
Execution
Unlocking
Prepared by R. Arthy, AP/IT
79. (contd…)
Four different combinations for managing
two – phase locking:
Simultaneous Locking and Simultaneous Release
Incremental Locking and Simultaneous Release
Simultaneous Locking and Incremental release
Incremental Locking and Incremental Release
Prepared by R. Arthy, AP/IT
80. (contd…)
Simultaneous and Simultaneous Release
Locking, execution and unlocking are applied
atomically
Next phase begin only when the last phase
competes successfully
Start and end locking ------> start and end of
transaction ------ start and end of unlocking
The failure of one phase do not affect other
phase
Prepared by R. Arthy, AP/IT
82. (contd…)
Incremental Locking
and Simultaneous
Release
Locking and execution
phases are interleaved
and precede the entire
unlocking phase
Lock ------ process
-------- lock ----
process ----- unlock
Deadlock
Prepared by R. Arthy, AP/IT
83. (contd…)
Simultaneous Locking and
Incremental Release
Growing phase is atomic
Unlock phase is
interleaved with execution
phase
Locking ---- execution
------ unlock------
execution ------ unlock
Expensive to manage
cascading than deadlock
Prepared by R. Arthy, AP/IT
84. (contd…)
Incremental Locking
and Incremental
Release
Execution phase is
interleaved with both
locking and release
phase
Suffers from deadlock
and cascading
Objective to minimize
transaction waiting time
Prepared by R. Arthy, AP/IT
85. 4.4.2 Multigranularity Locking
Locking units are of different sizes
This diversity defines a hierarchy of lockable
granularity
In this scheme a transaction Ti locks data
items in a hierarchical manner in different
locking modes
Use – transactions which access and modify
large amount of data
Prepared by R. Arthy, AP/IT
86. (contd…)
Five different lock modes
Read
Write
Intention Read – IR
Intention Write - IW
Read Intention Write - IRW
Prepared by R. Arthy, AP/IT
88. (contd…)
Suppose a transaction Ti wants to read file3 and
Tj wants to write to R32 . The execution Ti and Tj
goes as follows
Ti intends to re4ad File3, which a node of the root
database so it applies ir lock to database
It applies ir lock to Area1
Finally it applies a r lock to File3
Tj applies iw lock to database successfully
Prepared by R. Arthy, AP/IT
89. (contd…)
It applies iw lock to Area1 successfully
It cannot apply iw to File3 becase the lock
conflicts with Ti’s lock r
Ti releases r from File3
Tj now sets iw on File3 and applies won R32
Tk wants to read Area1 so it successfully sets ir
on database
It tries to set r lock on Area 1 but it conflicts with
Tj’s lock (iw)
It waits for Tj to release its iw lock on Area 1
Prepared by R. Arthy, AP/IT
90. 4.4.3 Heuristic Approach
Locking protocol – conflict occurs when the
transaction requesting the same data item is
blocked
Incremental Approach – Deadlock
Solution – Rollback – increases transaction
waiting time
Solution – immediately rollback
Prepared by R. Arthy, AP/IT
91. a. Cautious Waiting
Improvement over Wound wait (WW) and
Wait – Die mechanism
Conflict is resolved by rolling back / blocking
one of the conflicting transaction
Rollback is down based on the transaction
status
Rollback only when the holder is in a blocked
state
Prepared by R. Arthy, AP/IT
92. (contd…)
Properties
It is non preemptive- it never aborts during the
conflict
The wait – for graph can have a queue length
greater than one
It is deadlock free
It can be optimized if in the conflict transaction,
the amount of resource utilized by the conflicting
transaction is taken into consideration
Prepared by R. Arthy, AP/IT
93. b. Running Priority
Blocks if the transaction of holder is running
Conflict transaction aborts (waits) – others
continue
Prepared by R. Arthy, AP/IT
94. c. Krishna
Uses dynamic attributes of conflicting
transactions to resolve conflict
Transactions during their execution life
inherits a number of attributes
Example attributes: # of conflicts suffered by
a transaction, # of entities locked by the
transaction, duration the transaction waited
for the desired data time,…
Prepared by R. Arthy, AP/IT
95. (contd…)
Dynamic attribute set can be represented as
DAS = {a1, a2, …
Conflicting resolution scheme
Computes priorities of conflicting transaction –
uses this to resolve conflict
DASj = {a1, a2, …, an}
DASk = {b1, b2, …, bn}
Pj and Pk = priorities of Tj and Tk
Prepared by R. Arthy, AP/IT
98. 4.4.4 Non – Locking Based Schema
To lock or unlock an data item, detection of
deadlock an preventing
a few thousand instructions have to be
executed each time
To eliminate these overheads, timestamp
based schemes were used
Prepared by R. Arthy, AP/IT
99. (contd…)
Simple timestamping scheme:
TS(Q)>TS(Ti) = transaction came too late and the
access is not allowed
Rollback
Higher timestamp
Problem: can’t differentiate read and write locks
Prepared by R. Arthy, AP/IT
100. (contd…)
Basic Timestamping Scheme:
Each data items have two timestamp – to resolve
read – write and write – write conflicts
RTS(Q) compared WTS(Q)
Prepared by R. Arthy, AP/IT
101. 4.4.5. Concurrency Control
Mechanism
Need for maintaining database consistency
Mechanism
Locking – Based CCM
CCM Based on Epsilon Serializability
Relationship with ESR
Prepared by R. Arthy, AP/IT
102. a. Locking – Based CCM
Two – phase incremental locking and
simultaneous release
Three different ways:
Centralized two – phase locking
Primary copy locking
Distributed two – phase locking
Prepared by R. Arthy, AP/IT
103. a. i. Centralized Two – Phase
Locking
One node is responsible for managing all
locking activities
Locking request traffic is very high – central
node should be always available
In a mobile database system, this requirement
limits the choice of central node
Prepared by R. Arthy, AP/IT
104. (contd…)
A mobile unit cannot be a central node
because:
It is a kind of personal processing unit
It is not powerful enough to manage locking
requests
It cannot maintain the status of data items
It is not fully connected to other nodes in the
network
Its mobility is unpredictable
Prepared by R. Arthy, AP/IT
105. (contd…)
Base station is the next choice but there is
problems related mainly with functionality
issues
A fixed station is attached with the BS
Problem – Single point failure
Prepared by R. Arthy, AP/IT
106. a. ii. Primary Copy Two – Phase
Locking
Eliminates a single point of failure
Each lock manager is now responsible fir a
subset of data items
The node executing a part is the transaction
sends lock request to appropriate lock
manager
Problem – identifying suitable sited for
distributing locking responsibility
Choice – BS or FH or both
Prepared by R. Arthy, AP/IT
107. a. iii. Distributed Two – Phase
Locking
Maximized the extent of lock distribution
All nodes can serve as a lock manager
Prepared by R. Arthy, AP/IT
108. a (contd…)
Include separate database servers connected
to base stations through wired network
Communication overhead for managing
locking and unlocking requests is another
problem
Prepared by R. Arthy, AP/IT
109. a. (contd…)
If a mobile unit makes a lock request on
behalf of a transaction, it executed and then
It will send the request to lock manager site
The lock manager will decide to grant or to refuse
the lock and send the result to the mobile unit
The mobile unit makes the decision to continue
with forward processing or block or rollback
depending upon lock manager’s decision
Prepared by R. Arthy, AP/IT
110. Distributed HP – 2PL CCM
Based on two phase locking and extension of
HP – 2PL CCM
Uses conflict resolution scheme of caution
waiting mechanism to reduce the degree of
transaction roll – backs
Each BS – lock scheduler
Prepared by R. Arthy, AP/IT
111. Steps
On a conflict check the priority of the holder and the requestor
It Priority (Tr) > Priority (Th) then check the status of (Th). If (Th) is
not committing then check if it is a local transaction
It (Th) is a local transaction then restart it locally
If (Th) is a global transaction the restart it globally
If (Th) is in committing process then it is not restarted rather the (Tr)
is forced to wait until (Th) commits and releases all its lock
Adjust its Priority of (Th) as follows
Priority (Th) := Priority (Tr) + some fixed priority level
If Priority (Tr) <= Priority (Th) then block (Tr) until (Th) commits
and release its locks
Prepared by R. Arthy, AP/IT
112. b. CCM Based on Epsilon
Serializability
Tolerates limited amount of inconsistency
Based on two –tier replication scheme
Advantage – availability, accommodates the
disconnection problem and is scalable
Reduces transaction commit time and number of
transaction rejections
Metric space S is defined as a state space having
the following properties”
Distance function dist(u,v)
Triangular inequality
Symmetry
Prepared by R. Arthy, AP/IT
113. (contd…)
BS can broadcast information to all the MUs
I its cell
A central server holds and manages the
database D = {Di}, i Є N and Di Є S
di – current value of the data object D
ni – number of replicas of Di in MDS
∆ - amount of change can occur on each
replica at each MU
Prepared by R. Arthy, AP/IT
114. Steps at a DBS
∆i is calculated for each object Di
A timeout value r is linked with ∆i values of the data
item
DBS broadcasts the values if (di, ∆i) for each data
item and a timeout r for these values at the beginning
of the broadcast cycle
The DBS either receives pre – committed
transactions or can receive request transactions
The DBS serializes the pre – committed transactions
according to their order of arrival
Prepared by R. Arthy, AP/IT
115. Steps at MU
MU has the value of (di, ∆i) and the timeout r for
every data item Di it has cached
MU executes transaction ti. It changes the current
value of Di by ∆i-ti.
The value ∆i-ti is added ∆i-e. The following cases
are possible depending in the value of ∆i-ti and ∆i-e
If ∆i-ti <= ∆i and ∆i-e <= ∆i, then ti is committed at MU
and it is sent to DBS for re – execution
If ∆i-ti <= ∆i and ∆i-e > ∆i, then ti is blocked at MU until
new set of (Di, ∆i) is broadcasted by the server
If ∆i-ti > ∆i then ti is blocked at MU and submitted to the
server as a request transaction
Prepared by R. Arthy, AP/IT
116. c. Relationship with ESR
The mechanism for maintaining ESR has two
methods:
Divergence Control (DC)
Consistency Restoration (CR)
Prepared by R. Arthy, AP/IT
118. Introduction
The entire process of commit has two
phases:
Checking the intention of each node
participating in the execution of a
transaction
Collecting the intensions of
participants and committing the
transaction
Prepared by R. Arthy, AP/IT
119. Two – Phase Commit Protocol –
Centralized 2PC
Assumption – a distributed database system with
multiple nodes
Coordinator fragments Ti and distributes then to a
set of participants
The coordinator may or may not keep the fragments
for itself
The protocol makes sure of the following:
Participants’ decision
Decision change
Coordinator’s decision
No Failure
With failure
Prepared by R. Arthy, AP/IT
120. (contd…)
Steps:
Transaction fragmentation and distribution
Voting Phase
Voting
Participants’ vote
Decision Phase
Commit decision and dispatch
Participants decision
Prepared by R. Arthy, AP/IT
121. Node Failure and Timeout Action
Occurrences of infinite wait because of node
failure
One scheme – timeout action
How long a participant to wait
Coordinator sent commit – reaches subset of
participants
To handle immature abort by a timeout,
cooperative termination protocol can be used
Prepared by R. Arthy, AP/IT
122. Cooperative Termination Protocol
Two options:
Ask the coordinator about its last message
Ask one of its neighbor participants
To evaluate the cost of communication, two
parameters are used
Time complexity
Message complexity
Prepared by R. Arthy, AP/IT
123. Linear or Nested 2PC
In linear 2PC the message complexity is
reduced by collecting votes serially
Prepared by R. Arthy, AP/IT
125. Log Management in Mobile Database
Systems
Log is a sequential file where information
necessary for recovery is recorded
Each log record represents a unit of
information
The position of a record in the log identifies
the relative order of the occurrences of the
event the record represents
Property – Write Ahead Logging (WAL)
Prepared by R. Arthy, AP/IT
126. Where to Save the Log?
MSC
BS
MU
Prepared by R. Arthy, AP/IT
127. Logging Scheme
Centralized Logging – Saving of log at a designated
site
Drawback
It has very low reliability
Logging may become a bottleneck
Home Logging
Drawback
Scattered over a number of base stations
It may not work for Location dependent data
Poor availability
Prepared by R. Arthy, AP/IT
128. (contd…)
At all visited base stations
Log is saved at the BS of the cell it is currently
visiting
Lazy scheme
Pessimistic scheme
Logs are stored on the current BS and if the MU
moves to a new BS, a pointer to the old BS is
stored in the new BS
It has a large recovery time because it require
unification of log portions
Prepared by R. Arthy, AP/IT
129. Mobile Database Recovery Schemes
Three – phase Hybrid Recovery Scheme
Low – Cost Checkpointing and Failure Recovery
A Mobile Agent – Based Log Management Scheme
Architecture of Agent – Based Logging Scheme
Interaction among agents for log management
Forward strategy
Forward Log Unification Scheme
Forward Notification Scheme
Prepared by R. Arthy, AP/IT
130. Three – Phase Hybrid Recovery
Scheme
Prepared by R. Arthy, AP/IT
134. A Mobile Agent – Based Log
Management Scheme
Mobile agent is used
MA – is an autonomous program that can
move from machine to machine in a
heterogeneous network under its own control
Advantages of MA
Protocol Encapsulation
Robustness and fault – tolerance
Asynchronous and autonomous execution
Prepared by R. Arthy, AP/IT
135. Architecture of Agent – Based
Logging Scheme
Components
Bootstrap Agent
Base Agent
Home Agent
Coordinator Agent
Event Agent
Driver Agent
Prepared by R. Arthy, AP/IT
136. Interaction Among Agents for Log
Management
Interaction of CoAg and HoAg
Action of agent when handoff occurs
Prepared by R. Arthy, AP/IT