This document discusses approaches for specifying dependability and security requirements, including risk-driven, safety, and reliability specifications. It covers topics such as identifying risks and hazards, assessing their likelihood and impacts, analyzing root causes using techniques like fault trees, and defining requirements to reduce risks and prevent accidents. Safety requirements for an insulin pump example are provided. The key points are that risk analysis identifies risks that could lead to accidents, hazards are decomposed to discover their causes, and safety requirements ensure hazards do not occur or are limited if they do.
The document discusses techniques for developing dependable software systems, including fault avoidance, fault tolerance, and fault detection. It describes dependable programming practices like structured programming and exception handling. It also covers fault tolerance mechanisms like redundancy, diversity, and architectures like N-version programming which implement multiple versions of the system and vote on the output.
Layer of Protection Analysis (LOPA) is an effective semi-quantitative tool for process hazard analysis and risk assessment. It lies between qualitative and quantitative analysis. LOPA evaluates risks by analyzing accident scenarios, their likelihood and severity. It also considers independent protective layers that can prevent or mitigate consequences. The key steps of LOPA include establishing consequence criteria, identifying scenarios, evaluating frequency and severity, examining protective layers, and comparing results to risk tolerance limits. LOPA is useful for decision making regarding safety systems and managing risks cost effectively.
This document discusses principles of software safety for clinical information systems and electronic medical records (EMRs). It provides background on software safety incidents in other industries. Key concepts discussed include adjusting the software development methodology based on risk level, and that no software is completely safe. The document advocates analyzing EMR software to understand how defects could contribute to patient safety risk scenarios from minor to catastrophic. It suggests increased rigor for software that controls computerized protocols, clinical data posting and updating, and overall EMR performance and availability.
This document provides an overview and definitions related to Safety Instrumented Systems (SIS). It discusses the need for SIS to protect personnel, equipment, and the environment from hazardous events in industries like chemical and oil & gas. SIS are designed to reduce the likelihood or impact of emergencies. The document defines common SIS terms and describes the basic components and purpose of SIS, which include sensors to detect process parameters, a logic solver to determine necessary actions, and final control elements like valves to isolate the process. It also discusses the concept of layers of protection to prevent and mitigate hazardous events, with SIS comprising the final active prevention layer.
The combustion process has always been considered having the potential for a hazardous event which could lead to personnel injury or loss of production. To mitigate this risk, the process industry is now implementing Safety Instrumented Systems which can identify hazardous operating conditions and correctly respond in such a way to bring the combustion process back to a safe operating condition or implement an automatically controlled shutdown sequence to reduce the risk of operator error causing a catastrophic event. Oxygen and combustible flue gas analyzers are now being utilized in these combustion Safety Instrumented Systems (SIS) to identify hazardous operating conditions and automatically return the process to a safe state. The standards of IEC 61511 and API RP 556 will be reviewed as they apply to flue gas analyzers, as well as the process variables of the oxygen and combustible analyzer available for implementation into the SIS system for combustion monitoring, and the resultant actions required to return the process to a safe condition.
Safety instrumented systems angela summers Ahmed Gamal
This document discusses safety instrumented systems (SIS), which are designed to respond to hazardous conditions in industrial plants. An SIS monitors for conditions that could become hazardous and responds by taking actions to prevent or mitigate hazards. Examples provided include a furnace that shuts off fuel valves in response to high pressure and a reactor that opens a coolant valve when temperature rises too high. The document outlines standards for good engineering practices in designing, implementing, and maintaining SIS according to lifecycle phases from planning and design to operations and auditing. Key aspects covered are managing risks to people and procedures, assessing and mitigating risk through assigning safety integrity levels, and proving that SIS designs achieve the desired safety functionality.
5 Ways to Be Vigilant for your Medical Devices from a Cybersecurity PerspectiveEMMAIntl
When I was working on a web application as a developer, I always noticed two small issues. The identified issues included data getting stored in the browser’s “session” storage and the display of the user ID in the location of the web page. To simply define session storage, it is the data stored inside the browser when a user logs in. Surely, while building applications or for testing, this is indeed a common practice where this session data gets referred multiple times. But in cases where critical data is getting saved in sessions such as a user or admin ID, it would be of major concern as session data is easily accessible by anyone. Truly, it is of major concern when the application is linked to a medical device such as a cardiac implant...
The document discusses techniques for developing dependable software systems, including fault avoidance, fault tolerance, and fault detection. It describes dependable programming practices like structured programming and exception handling. It also covers fault tolerance mechanisms like redundancy, diversity, and architectures like N-version programming which implement multiple versions of the system and vote on the output.
Layer of Protection Analysis (LOPA) is an effective semi-quantitative tool for process hazard analysis and risk assessment. It lies between qualitative and quantitative analysis. LOPA evaluates risks by analyzing accident scenarios, their likelihood and severity. It also considers independent protective layers that can prevent or mitigate consequences. The key steps of LOPA include establishing consequence criteria, identifying scenarios, evaluating frequency and severity, examining protective layers, and comparing results to risk tolerance limits. LOPA is useful for decision making regarding safety systems and managing risks cost effectively.
This document discusses principles of software safety for clinical information systems and electronic medical records (EMRs). It provides background on software safety incidents in other industries. Key concepts discussed include adjusting the software development methodology based on risk level, and that no software is completely safe. The document advocates analyzing EMR software to understand how defects could contribute to patient safety risk scenarios from minor to catastrophic. It suggests increased rigor for software that controls computerized protocols, clinical data posting and updating, and overall EMR performance and availability.
This document provides an overview and definitions related to Safety Instrumented Systems (SIS). It discusses the need for SIS to protect personnel, equipment, and the environment from hazardous events in industries like chemical and oil & gas. SIS are designed to reduce the likelihood or impact of emergencies. The document defines common SIS terms and describes the basic components and purpose of SIS, which include sensors to detect process parameters, a logic solver to determine necessary actions, and final control elements like valves to isolate the process. It also discusses the concept of layers of protection to prevent and mitigate hazardous events, with SIS comprising the final active prevention layer.
The combustion process has always been considered having the potential for a hazardous event which could lead to personnel injury or loss of production. To mitigate this risk, the process industry is now implementing Safety Instrumented Systems which can identify hazardous operating conditions and correctly respond in such a way to bring the combustion process back to a safe operating condition or implement an automatically controlled shutdown sequence to reduce the risk of operator error causing a catastrophic event. Oxygen and combustible flue gas analyzers are now being utilized in these combustion Safety Instrumented Systems (SIS) to identify hazardous operating conditions and automatically return the process to a safe state. The standards of IEC 61511 and API RP 556 will be reviewed as they apply to flue gas analyzers, as well as the process variables of the oxygen and combustible analyzer available for implementation into the SIS system for combustion monitoring, and the resultant actions required to return the process to a safe condition.
Safety instrumented systems angela summers Ahmed Gamal
This document discusses safety instrumented systems (SIS), which are designed to respond to hazardous conditions in industrial plants. An SIS monitors for conditions that could become hazardous and responds by taking actions to prevent or mitigate hazards. Examples provided include a furnace that shuts off fuel valves in response to high pressure and a reactor that opens a coolant valve when temperature rises too high. The document outlines standards for good engineering practices in designing, implementing, and maintaining SIS according to lifecycle phases from planning and design to operations and auditing. Key aspects covered are managing risks to people and procedures, assessing and mitigating risk through assigning safety integrity levels, and proving that SIS designs achieve the desired safety functionality.
5 Ways to Be Vigilant for your Medical Devices from a Cybersecurity PerspectiveEMMAIntl
When I was working on a web application as a developer, I always noticed two small issues. The identified issues included data getting stored in the browser’s “session” storage and the display of the user ID in the location of the web page. To simply define session storage, it is the data stored inside the browser when a user logs in. Surely, while building applications or for testing, this is indeed a common practice where this session data gets referred multiple times. But in cases where critical data is getting saved in sessions such as a user or admin ID, it would be of major concern as session data is easily accessible by anyone. Truly, it is of major concern when the application is linked to a medical device such as a cardiac implant...
Software Failure Air Traffic Control SystemShakeel Ahmed
An air traffic control system in Los Angeles failed, losing contact with 400 airplanes. The main system failed and the backup system did not take over as expected. The failure was due to a software timing issue - the system had a countdown timer that would reset too high, causing the system to shut down after 50 days without being restarted. This known issue was an oversight by the manufacturer and exposed system to failure by not addressing the problem as instructed. The failure highlights the risks of technical deficiencies and lack of client participation in complex software projects.
The document discusses the Technique for Human Error Prediction (THERP) method for predicting human error probabilities and evaluating how human errors can impact systems. THERP involves detailed task analysis, estimating error probabilities based on performance shaping factors, and recommending system changes. It outlines the THERP procedure and notes advantages like being easy to use, but also limitations like excessive focus on procedures. The document also discusses challenges in obtaining reliable human performance data to estimate error probabilities.
Safety-critical systems are computer systems whose failure could result in injury, death, or environmental damage. Examples include aircraft control systems, nuclear power plant controls, medical devices like pacemakers, and railway signaling systems. These systems require high integrity to avoid hazards and ensure safety. Techniques like developing diverse redundant systems can improve safety by detecting and tolerating a wider range of faults.
White paper - Actionable Alarming - Wonderware-Schneider ElectricSuman Singh
A whitepaper on actionable alarm management by Rob Kambach, Product Manager, System Platform, Wonderware/Schneider Electric. Read the paper and learn how to manage your SCADA alarms better!
State-of-the-Art: Industry Challenges in ERMs0P5a41b
1. Make Sence Florida has identified several challenges that organizations face when implementing enterprise risk management practices and software solutions. These challenges include an inability to effectively handle large amounts of risk data, degraded data quality, data being forced to fit predefined models rather than reflecting real risks, ineffective filtering of data leading to missed risks, poor communication between different parts of the organization, and silos working independently without oversight.
2. Current risk management software provides some benefits like data aggregation but does not fully address these challenges. Manual processes used to select and analyze risk data can propagate human biases and errors. Without comprehensive solutions, organizations remain exposed to significant risks going unnoticed.
SaMD or Software as a Medical Device can be described as a software constructed to be used in medical devices. These softwares can be run on different operating systems and virtual platforms.
1. The basic programming model of a SaMD is given below.
2. Different softwares are used for medical purposes, and they include the following:
To continue Reading : https://bit.ly/31ItRVc
Contact Us:
Website : https://bit.ly/2BvO06b
Email us: sales.cro@pepgra.com
Whatsapp: +91 9884350006
This document provides an overview of Layer of Protection Analysis (LOPA), a semi-quantitative risk assessment tool. LOPA evaluates risk scenarios by analyzing the initiating event frequency, consequence severity if the scenario occurs, and likelihood of failure of independent protection layers. The document discusses how to identify scenarios and protection layers, estimate initiating event frequencies and protection layer failure probabilities, and calculate risk. LOPA is used to determine if sufficient protection layers exist to reduce risk to a tolerable level for a given scenario.
Wireless Infusion Pumps: Securing Hospitals’ Most Ubiquitous Medical DevicePriyanka Aash
This document discusses securing wireless infusion pumps in hospitals. It identifies risks like patient safety and operational downtime. Vulnerabilities of infusion pumps include long useful lifespans, poor protection and patching, and lack of detection and alerting. Demonstrations show how pumps could be exploited by compromising patient information or crashing communication systems. Challenges to securing pumps include firmware version control, access control, and alarms. The National Cybersecurity Center of Excellence's strategy is to help healthcare organizations understand risks and secure medical devices through building example implementations and publishing best practice guides.
Master Data, From Inspection to Analytics to Business DecisionPreston Johnson
Machinery inspection data comes in a variety of forms, from vibration to ultrasound to infrared and oil analysis to motor current and human observations.
Each data set has its own characteristics, its own ability to detect defects in our equipment, and its own data formats.
Unifying these data items into a collaborative system is a multi-step process, yielding a trans-formative life of data and resulting information.
This presentation describes the data types, initial meta data, and equipment conditioning indicating features we can extract from the data.
From this point, condition indicating features combine in new forms to provide a holistic view of equipment health when combined with domain knowledge.
The presentation describes the fusion of inspection data sources with encapsulated domain knowledge that facilitates rapid assessments of machine health.
Case studies and a review of commercial systems supporting these concepts are provided to illustrate data management concepts described.
Automated Framework for Vision based Driver Fatigue Detection by using Multi-...IRJET Journal
This document describes a framework for detecting driver fatigue using computer vision techniques. It uses the Viola-Jones algorithm to detect the face and eyes in images captured of the driver. Eye closure over consecutive frames is used to determine if the driver is drowsy. Different techniques for driver monitoring like intrusive biometrics and non-intrusive computer vision are discussed. The proposed method uses support vector machines to classify driving behavior metrics like distance to lane boundaries as normal or abnormal based on a driving simulator experiment. Sending alerts to authorities when drowsiness is detected could help reduce accidents from fatigued driving.
This document discusses the history and capabilities of infusion pumps and the benefits of wireless infusion pump technology. It covers how wireless pumps have evolved from basic pumps to smart, networked pumps that can communicate with EMR systems. The document outlines five prerequisites for infusion pump integration, including wireless connectivity and electronic medication orders. It details the benefits of wireless pumps for patients, nurses, pharmacists, and executives, including increased safety and decreased errors. It also addresses considerations and challenges of implementing wireless pump technology.
Anomaly Detection for Preventive MaintenanceOrzota
Detecting anomalies in sensor events is a requirement for a wide variety of use cases in the industrial IoT. Examples include predicting failures of HVAC systems and elevators for property management to identifying potential signals of malfunction in aircraft engines to schedule preventive maintenance.
Unlike prediction models for customer churn, inventory forecasts, etc. that rely on multiple sources of data and a wide range of domain-specific parameters, it is possible to detect anomalies for many types of time-series data using statistical techniques alone. In this presentation, we will discuss the types of anomalies and some available models for anomaly detection.
This document discusses electrical reliability solutions for healthcare facilities from High Voltage Maintenance. It highlights that unreliable power can be detrimental for patient lives and finances. It offers customized maintenance programs to evaluate aging electrical equipment, ensure compliance with healthcare standards, and provide 24/7 emergency support. Services include condition assessments, testing technologies, and reliability-centered maintenance to increase system availability at reduced costs.
This document discusses using dynamic adaptive systems in safety-critical domains. It begins by introducing safety-critical cyber-physical systems and how dynamic adaptivity could provide benefits like increased fault tolerance and deployability. However, adaptivity also introduces challenges for testing and certification. The document then discusses using the Architecture Analysis and Design Language (AADL) to model and analyze dynamic adaptive safety-critical systems. It considers issues like what constitutes sufficient pre-deployment testing of such systems and how failures from untested configurations can be mitigated. Overall, the document explores how to incorporate safety-critical concerns into the design of dynamic adaptive systems.
Computer networks--introduction computer-networkingOlorunyomi Segun
This document provides an introduction to computer networking for students. It discusses the basic components and types of computer networks, including peer-to-peer and client-server networks. It also covers topics such as wired and wireless networking, networking hardware components like switches and routers, and considerations for setting up a school network. The document aims to help students understand computer networking and assist with planning network development at their school.
This document discusses exploratory data analysis (EDA) and its application to analyzing computer networking data. EDA involves graphically summarizing data to uncover patterns, relationships, and structure without formal hypothesis testing. The document outlines the EDA process, including identifying key metrics and factors to explore. It provides examples of EDA graphs that could be used to analyze simulated WiFi data, examining how various factors like vendor, user type, and distance affect network performance metrics. The goal of EDA is to gain insights, detect anomalies, and inform modeling before running extensive simulations or experiments.
Beit 381 se lec 20 - 31 - 12 apr25 - case tools and ascent1-55babak danyal
This document discusses Computer Aided Software Engineering (CASE) tools. It describes CASE tools as programs that support various software development activities like requirements analysis, modeling, debugging and testing. It categorizes CASE tools based on their functions, the development activities they support, their depth or scope, and how integrated they are. Examples of common CASE tools include editors, analysis tools, report generators, code generators, and change management tools. The document also discusses how CASE tools have evolved over time to better support the software development process.
Ian Sommerville, Software Engineering, 9th Edition Ch 23Mohammed Romi
The document discusses project planning for software development. It covers topics like software pricing, plan-driven development, project scheduling, and estimation techniques. Project planning involves breaking down work, anticipating problems, and preparing tentative solutions. A project plan is created at the start of a project to communicate the work breakdown and help assess progress. Planning is done at various stages including proposals, project startup, and periodically throughout the project. Factors like requirements, costs, and risks are considered in planning.
The document discusses requirements engineering and summarizes key topics covered in Chapter 4, including:
- Functional and non-functional requirements and how they differ
- The structure and purpose of a software requirements specification document
- Methods for specifying requirements such as using natural language, structured specifications, and tables
- Challenges in writing requirements clearly and avoiding ambiguity or mixing of requirement types
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, IPv4 addressing and packet format, fragmentation, and IPv6 advantages over IPv4 such as a larger address space and better header format. Key aspects of IPv4 include the header length field, total length field, identification field for fragmentation, flags, fragmentation offset, checksum, and protocol field. IPv6 improvements include a fixed header length, larger addresses, priority and flow label fields, and extension headers.
Software Failure Air Traffic Control SystemShakeel Ahmed
An air traffic control system in Los Angeles failed, losing contact with 400 airplanes. The main system failed and the backup system did not take over as expected. The failure was due to a software timing issue - the system had a countdown timer that would reset too high, causing the system to shut down after 50 days without being restarted. This known issue was an oversight by the manufacturer and exposed system to failure by not addressing the problem as instructed. The failure highlights the risks of technical deficiencies and lack of client participation in complex software projects.
The document discusses the Technique for Human Error Prediction (THERP) method for predicting human error probabilities and evaluating how human errors can impact systems. THERP involves detailed task analysis, estimating error probabilities based on performance shaping factors, and recommending system changes. It outlines the THERP procedure and notes advantages like being easy to use, but also limitations like excessive focus on procedures. The document also discusses challenges in obtaining reliable human performance data to estimate error probabilities.
Safety-critical systems are computer systems whose failure could result in injury, death, or environmental damage. Examples include aircraft control systems, nuclear power plant controls, medical devices like pacemakers, and railway signaling systems. These systems require high integrity to avoid hazards and ensure safety. Techniques like developing diverse redundant systems can improve safety by detecting and tolerating a wider range of faults.
White paper - Actionable Alarming - Wonderware-Schneider ElectricSuman Singh
A whitepaper on actionable alarm management by Rob Kambach, Product Manager, System Platform, Wonderware/Schneider Electric. Read the paper and learn how to manage your SCADA alarms better!
State-of-the-Art: Industry Challenges in ERMs0P5a41b
1. Make Sence Florida has identified several challenges that organizations face when implementing enterprise risk management practices and software solutions. These challenges include an inability to effectively handle large amounts of risk data, degraded data quality, data being forced to fit predefined models rather than reflecting real risks, ineffective filtering of data leading to missed risks, poor communication between different parts of the organization, and silos working independently without oversight.
2. Current risk management software provides some benefits like data aggregation but does not fully address these challenges. Manual processes used to select and analyze risk data can propagate human biases and errors. Without comprehensive solutions, organizations remain exposed to significant risks going unnoticed.
SaMD or Software as a Medical Device can be described as a software constructed to be used in medical devices. These softwares can be run on different operating systems and virtual platforms.
1. The basic programming model of a SaMD is given below.
2. Different softwares are used for medical purposes, and they include the following:
To continue Reading : https://bit.ly/31ItRVc
Contact Us:
Website : https://bit.ly/2BvO06b
Email us: sales.cro@pepgra.com
Whatsapp: +91 9884350006
This document provides an overview of Layer of Protection Analysis (LOPA), a semi-quantitative risk assessment tool. LOPA evaluates risk scenarios by analyzing the initiating event frequency, consequence severity if the scenario occurs, and likelihood of failure of independent protection layers. The document discusses how to identify scenarios and protection layers, estimate initiating event frequencies and protection layer failure probabilities, and calculate risk. LOPA is used to determine if sufficient protection layers exist to reduce risk to a tolerable level for a given scenario.
Wireless Infusion Pumps: Securing Hospitals’ Most Ubiquitous Medical DevicePriyanka Aash
This document discusses securing wireless infusion pumps in hospitals. It identifies risks like patient safety and operational downtime. Vulnerabilities of infusion pumps include long useful lifespans, poor protection and patching, and lack of detection and alerting. Demonstrations show how pumps could be exploited by compromising patient information or crashing communication systems. Challenges to securing pumps include firmware version control, access control, and alarms. The National Cybersecurity Center of Excellence's strategy is to help healthcare organizations understand risks and secure medical devices through building example implementations and publishing best practice guides.
Master Data, From Inspection to Analytics to Business DecisionPreston Johnson
Machinery inspection data comes in a variety of forms, from vibration to ultrasound to infrared and oil analysis to motor current and human observations.
Each data set has its own characteristics, its own ability to detect defects in our equipment, and its own data formats.
Unifying these data items into a collaborative system is a multi-step process, yielding a trans-formative life of data and resulting information.
This presentation describes the data types, initial meta data, and equipment conditioning indicating features we can extract from the data.
From this point, condition indicating features combine in new forms to provide a holistic view of equipment health when combined with domain knowledge.
The presentation describes the fusion of inspection data sources with encapsulated domain knowledge that facilitates rapid assessments of machine health.
Case studies and a review of commercial systems supporting these concepts are provided to illustrate data management concepts described.
Automated Framework for Vision based Driver Fatigue Detection by using Multi-...IRJET Journal
This document describes a framework for detecting driver fatigue using computer vision techniques. It uses the Viola-Jones algorithm to detect the face and eyes in images captured of the driver. Eye closure over consecutive frames is used to determine if the driver is drowsy. Different techniques for driver monitoring like intrusive biometrics and non-intrusive computer vision are discussed. The proposed method uses support vector machines to classify driving behavior metrics like distance to lane boundaries as normal or abnormal based on a driving simulator experiment. Sending alerts to authorities when drowsiness is detected could help reduce accidents from fatigued driving.
This document discusses the history and capabilities of infusion pumps and the benefits of wireless infusion pump technology. It covers how wireless pumps have evolved from basic pumps to smart, networked pumps that can communicate with EMR systems. The document outlines five prerequisites for infusion pump integration, including wireless connectivity and electronic medication orders. It details the benefits of wireless pumps for patients, nurses, pharmacists, and executives, including increased safety and decreased errors. It also addresses considerations and challenges of implementing wireless pump technology.
Anomaly Detection for Preventive MaintenanceOrzota
Detecting anomalies in sensor events is a requirement for a wide variety of use cases in the industrial IoT. Examples include predicting failures of HVAC systems and elevators for property management to identifying potential signals of malfunction in aircraft engines to schedule preventive maintenance.
Unlike prediction models for customer churn, inventory forecasts, etc. that rely on multiple sources of data and a wide range of domain-specific parameters, it is possible to detect anomalies for many types of time-series data using statistical techniques alone. In this presentation, we will discuss the types of anomalies and some available models for anomaly detection.
This document discusses electrical reliability solutions for healthcare facilities from High Voltage Maintenance. It highlights that unreliable power can be detrimental for patient lives and finances. It offers customized maintenance programs to evaluate aging electrical equipment, ensure compliance with healthcare standards, and provide 24/7 emergency support. Services include condition assessments, testing technologies, and reliability-centered maintenance to increase system availability at reduced costs.
This document discusses using dynamic adaptive systems in safety-critical domains. It begins by introducing safety-critical cyber-physical systems and how dynamic adaptivity could provide benefits like increased fault tolerance and deployability. However, adaptivity also introduces challenges for testing and certification. The document then discusses using the Architecture Analysis and Design Language (AADL) to model and analyze dynamic adaptive safety-critical systems. It considers issues like what constitutes sufficient pre-deployment testing of such systems and how failures from untested configurations can be mitigated. Overall, the document explores how to incorporate safety-critical concerns into the design of dynamic adaptive systems.
Computer networks--introduction computer-networkingOlorunyomi Segun
This document provides an introduction to computer networking for students. It discusses the basic components and types of computer networks, including peer-to-peer and client-server networks. It also covers topics such as wired and wireless networking, networking hardware components like switches and routers, and considerations for setting up a school network. The document aims to help students understand computer networking and assist with planning network development at their school.
This document discusses exploratory data analysis (EDA) and its application to analyzing computer networking data. EDA involves graphically summarizing data to uncover patterns, relationships, and structure without formal hypothesis testing. The document outlines the EDA process, including identifying key metrics and factors to explore. It provides examples of EDA graphs that could be used to analyze simulated WiFi data, examining how various factors like vendor, user type, and distance affect network performance metrics. The goal of EDA is to gain insights, detect anomalies, and inform modeling before running extensive simulations or experiments.
Beit 381 se lec 20 - 31 - 12 apr25 - case tools and ascent1-55babak danyal
This document discusses Computer Aided Software Engineering (CASE) tools. It describes CASE tools as programs that support various software development activities like requirements analysis, modeling, debugging and testing. It categorizes CASE tools based on their functions, the development activities they support, their depth or scope, and how integrated they are. Examples of common CASE tools include editors, analysis tools, report generators, code generators, and change management tools. The document also discusses how CASE tools have evolved over time to better support the software development process.
Ian Sommerville, Software Engineering, 9th Edition Ch 23Mohammed Romi
The document discusses project planning for software development. It covers topics like software pricing, plan-driven development, project scheduling, and estimation techniques. Project planning involves breaking down work, anticipating problems, and preparing tentative solutions. A project plan is created at the start of a project to communicate the work breakdown and help assess progress. Planning is done at various stages including proposals, project startup, and periodically throughout the project. Factors like requirements, costs, and risks are considered in planning.
The document discusses requirements engineering and summarizes key topics covered in Chapter 4, including:
- Functional and non-functional requirements and how they differ
- The structure and purpose of a software requirements specification document
- Methods for specifying requirements such as using natural language, structured specifications, and tables
- Challenges in writing requirements clearly and avoiding ambiguity or mixing of requirement types
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, IPv4 addressing and packet format, fragmentation, and IPv6 advantages over IPv4 such as a larger address space and better header format. Key aspects of IPv4 include the header length field, total length field, identification field for fragmentation, flags, fragmentation offset, checksum, and protocol field. IPv6 improvements include a fixed header length, larger addresses, priority and flow label fields, and extension headers.
The document discusses the design and implementation process in software engineering. It covers topics like using the Unified Modeling Language (UML) for object-oriented design, design patterns, and implementation issues. It then discusses the design process, including identifying system contexts and interactions, architectural design, identifying object classes, and creating design models like subsystem, sequence, and state diagrams. The example of designing a weather station system is used to illustrate these design concepts and activities.
The document discusses heavy-tailed distributions and their prevalence in computer networking. It begins with definitions of key concepts like outliers, heavy-tailed distributions, and how these distributions violate assumptions of traditional statistical analysis. Examples are given of heavy-tailedness in areas like web objects, video systems, and peer-to-peer networks. Specific distributions like Pareto and Weibull are mentioned as fitting networking metrics well. The document emphasizes that extreme observations are common in networks and should not be discarded without careful analysis.
Static analysis, reliability testing, and security testing are techniques for validating critical systems. Additional validation processes are required for critical systems due to the high costs and consequences of failure. Validation costs for critical systems are significantly higher than for non-critical systems, typically taking up more than 50% of total development costs. The outcome of the validation process is evidence that demonstrates the system's level of dependability.
Ian Sommerville, Software Engineering, 9th Edition Ch1Mohammed Romi
The document provides an introduction to software engineering concepts. It discusses what software engineering is, the importance of ethics in software development, and introduces three case studies that will be used as examples throughout the book. Specifically:
[1] It defines software engineering as an engineering discipline concerned with all aspects of software production. Professional and ethical practices are important.
[2] It discusses software engineering ethics and introduces the ACM/IEEE code of ethics for software engineers.
[3] It provides an overview of three case studies that will be referenced in later chapters: an insulin pump system, a patient management system, and a weather station system.
This document discusses different types of intelligent agents and their environments. It defines rational agents as those that do the right thing given their percepts and goals. The document outlines different types of agent architectures, including simple reflex agents, model-based reflex agents, goal-based agents, and utility-based agents. It also discusses properties of task environments and examples of different environments. Learning agents are introduced as agents that can improve their performance over time through experience.
Ian Sommerville, Software Engineering, 9th EditionCh 8Mohammed Romi
The document discusses different types of software testing including unit testing, component testing, and system testing. Unit testing involves testing individual program components in isolation through techniques like partition testing and guideline-based testing. Component testing focuses on testing interactions between components through their interfaces. System testing integrates components to test their interactions and check for emergent behaviors that are not explicitly defined. The document also covers test-driven development, which involves writing tests before code in incremental cycles.
Requirements validation certifies that the requirements document accurately describes the system to be built. It checks for completeness, consistency, standards compliance, and technical errors. Validation analyzes the final requirements document, while analysis works with initial requirements. Validation inputs include the requirements document and organizational standards. Outputs are a problem list and agreed actions. Requirements reviews involve analyzing the document for problems, discussing issues, and agreeing on solutions. Validation techniques include reviews, prototyping, modeling, and testing.
This document provides an overview of quality management in software engineering. It discusses software quality, standards, reviews and inspections, as well as software measurement and metrics. The key points covered include establishing an organizational framework for quality management, applying specific quality processes and standards at the project level, and conducting independent reviews to ensure compliance. Software metrics can help quantify attributes and identify anomalous components, but meaningful relationships between internal metrics and external quality attributes can be difficult to establish.
The document discusses architectural design in software engineering. It covers topics like architectural design decisions, views, patterns, and application architectures. Architectural design involves identifying major system components and their communications in order to represent the link between specification and design processes. Common architectural patterns discussed include model-view-controller, layered architectures, repositories, client-server, pipes and filters. The document also provides examples of architectures for different types of applications like transaction processing systems and information systems.
1. The document discusses different types of switched networks including circuit-switched, datagram, and virtual circuit networks. It describes the key characteristics of each type.
2. Circuit switching uses dedicated paths between nodes and has three phases: setup, data transfer, and teardown. Datagram networks treat each packet independently and route using destination addresses in packet headers. Virtual circuit networks combine aspects of circuit and datagram switching.
3. The structures of switches used in different networks are examined, including crossbar switches for circuit switching and various designs for packet switches like Banyan networks.
This document discusses project management and managing people on software projects. It covers topics like risk management, motivating team members, and dealing with different personality types. It provides an example of an individual motivation issue where a team member has lost interest in the project work and is no longer developing the skills they want. The project manager talks to the team member to understand the problem and find a way to re-engage them by addressing their skill development needs.
CASE tools and their effects on software qualityUtkarsh Agarwal
CASE tools can significantly improve software quality by automating tasks, reducing errors, and standardizing development processes. They provide functionality for data modeling, code generation, refactoring, documentation and more. While some aspects like requirements gathering require human input, overall CASE tools improve design, catch issues early, and allow developers to focus on other important work. Proper use of modeling languages and automation can dramatically enhance software quality across all stages of development.
This document provides an overview of topics covered in Chapter 7 on software design and implementation, including object-oriented design using UML, design patterns, implementation issues, and open source development. It discusses the design and implementation process, build vs buy approaches, object-oriented design processes involving system models, and key activities like defining system context, identifying objects and interfaces. Specific examples are provided for designing a wilderness weather station system.
This document summarizes Chapter 12 of a textbook on dependability and security specification. It discusses risk-driven specification, including identifying risks, analyzing risks, and defining requirements to reduce risks. It also covers specifying safety requirements by identifying hazards, assessing hazards, and analyzing hazards to discover root causes. The goal is to specify requirements that ensure systems function dependably and securely without failures causing harm.
This document discusses safety engineering for systems that contain software. It covers topics like safety-critical systems, safety requirements, and safety engineering processes. Safety is defined as a system's ability to operate normally and abnormally without harm. For safety-critical systems like aircraft or medical devices, software is often used for control and monitoring, so software safety is important. Hazard identification, risk assessment, and specifying safety requirements to mitigate risks are key parts of the safety engineering process. The goal is to design systems where failures cannot cause injury, death or environmental damage.
This document provides an overview of safety engineering concepts and processes. It discusses safety-critical systems and the importance of considering software safety. Safety is defined as a system's ability to operate without danger of injury or damage. Key concepts covered include safety requirements, hazard identification and analysis, risk assessment and reduction strategies, and safety engineering processes. Safety-critical systems must be designed and developed following strict processes to ensure all hazards are identified and mitigated.
The document discusses how to specify requirements for critical systems based on risk analysis. It explains how to identify risks, analyze and classify them, then derive safety, security, and reliability requirements to reduce risks. For reliability, it describes metrics like probability of failure on demand and mean time to failure that can be used to specify quantitative reliability levels. The goal is to develop requirements that eliminate intolerable risks and minimize other risks given cost and schedule constraints.
The document discusses critical systems specification, including risk-driven specification, safety specification, security specification, and software reliability specification. It covers topics like risk identification and analysis, safety requirements generation from risk analysis, derivation of security requirements, and metrics used for reliability specification like probability of failure on demand and rate of fault occurrence. The slides provide examples of how these techniques are applied to a hypothetical insulin pump system.
This document discusses requirements specification for critical systems. It covers dependability requirements, risk-driven specification, safety specification, security specification, system reliability specification, and non-functional reliability requirements. For risk-driven specification, it describes the stages of risk identification, analysis and classification, decomposition, and risk reduction assessment. It provides examples of applying this process to an insulin pump. For safety specification, it discusses safety requirements, the safety life cycle, and the IEC 61508 standard. For security specification, it outlines a similar process to safety with stages of asset identification, threat analysis, and security requirements specification. It also discusses different types of security requirements.
This document discusses Safety Instrumented Systems (SIS) and methods for determining risk reduction requirements. An SIS monitors industrial processes for dangerous conditions and executes actions to prevent or mitigate hazardous events. The document describes various methods to determine the necessary level of risk reduction for a given process, including risk graphs and Layer of Protection Analysis, both of which consider the consequences, frequency, possibility of avoidance, and probability of occurrence of an event. The determined risk reduction requirement is characterized by a Safety Integrity Level (SIL) on a scale of 1 to 4. An SIS provides risk reduction by successfully performing its safety functions, with its effectiveness measured by its probability of failure on demand (PFD).
Health apps regulation and quality control case studies and session 2 present...3GDR
The document discusses regulation and quality control of health apps. It begins with an overview of the digital health landscape and how different types of apps may be regulated to varying degrees. It then discusses challenges in managing chronic diseases and how data from apps and devices could potentially help transform care if delivered in an actionable way. The rest of the document discusses regulatory frameworks for medical software and apps, standards that may apply, and issues to consider like safety, security, usability and how to demonstrate safety for apps and systems that include software.
Health apps regulation and quality control case studies and session 2 present...3GDR
The document discusses regulation and quality control of health apps. It begins with an overview of the digital health landscape and how different types of apps may be regulated to varying degrees. It then discusses challenges in managing chronic diseases and how data from apps and devices could potentially help patients if transformed and delivered in an actionable way. The rest of the document discusses regulatory frameworks for medical software and apps, standards that may apply, and issues to consider like safety, security, usability and more. It also provides examples of how safety cases are used in other industries like nuclear to help build confidence in critical systems.
This document discusses risk assessment and management for quarries. It outlines the objectives of risk assessment, defines risk management principles, and describes various risk assessment methodologies including qualitative, quantitative, failure modes and effects analysis, and hazard and operability studies. The stages of risk management are identified as hazard identification, risk evaluation, and risk control. UK health and safety legislation requires employers to conduct suitable and efficient risk assessments to identify necessary risk control measures.
This document outlines the process of IT security risk assessment. It discusses key terminology like assets, threats, vulnerabilities, and risks. It then describes different approaches to security risk assessment like baseline, informal, formal, and combined. The detailed risk analysis process is also explained including steps like asset identification, threat identification, vulnerability identification, risk analysis, likelihood determination, impact analysis, risk determination, and control recommendations. Specific examples are provided to illustrate each step of the risk assessment process.
This document explains Safety Integrity Levels (SIL) which are used to quantify safety requirements for Safety Instrumented Systems. It discusses what SIL is, the four SIL levels and their required reliability, how SIL ratings are determined through a risk assessment process, and how hazards are protected against through a layered approach. The document also outlines the SIL life cycle including design, realization, and operation phases, how equipment failures can occur, and how a Safety Instrumented Function's performance is quantified through its Probability of Failure on Demand. It provides information on how components like actuators can be certified as "suitable for use" at a given SIL level and the role of proof and diagnostic testing.
The document discusses safety systems used in industrial plants, including emergency shutdown systems (ESD), process shutdown systems (PSD), and fire and gas control systems (F&G). It defines these terms and describes their objectives, typical components, and functions. Safety is measured by factors like average probability of failure on demand (PFDavg) and risk reduction factor (RRF). The document also covers related topics like hazard analysis, risk, reliability, availability, and definitions of key safety terminology.
Safety is an important consideration in process design. Safety integrity level (or SIL) is often used to describe process safety requirements. However, there are often misconceptions or misunder- standings surrounding SIL. While the general subject, functional safety and SIL, can be highly technical, the general ideas can be distilled down to a few readily understandable concepts. In this paper, we will discuss what SIL is, why it is important, what certification means, and the implications and benefits of that certification to the end user.
Drager Fixed Gas Detector - Functional Safety & Gas Detection Systems - SIL B...Thorne & Derrick UK
A process is assumed to be safe if the actual risk is decreased below the level of acceptable risk through risk-reducing measures. Safety instrumented systems use functional safety to automatically activate safety measures and avoid dangerous situations. The required reliability of protection systems depends on the safety integrity level (SIL), which is determined through risk analysis of potential consequences, exposure to hazards, and avoiding hazardous events. Gas detection systems must activate safety countermeasures if gas concentrations exceed defined levels. Their safety function is to trigger gas alarms, and upon failure must go to a safe state of equivalent alarm activation. The probability of failure for safety functions is evaluated to ensure protection systems meet the necessary SIL level through factors like proof testing and detectable versus undetectable
Safety, Risk, Hazard and Engineer’s Role Towards SafetyAli Sufyan
1. Safety engineering aims to identify hazards and ensure systems can operate safely without risk of injury, death, or environmental damage.
2. Engineers must consider safety in various fields such as aerospace, automotive, chemical, nuclear and ensure proper safety measures are implemented to prevent accidents from failures, errors or external threats.
3. Safety is critical in systems where failure could be catastrophic, like aircraft control systems, and engineers are responsible for thorough hazard analysis and mitigation of risks.
eHealth - Medical Systems Interoperability & Mobile Healthulmedical
The Medical Device industry is rapidly adopting technologies that enable communication and connectivity of health products and systems to improve both speed and quality of care as well as patient safety. The users (i.e. hospitals and others) are demanding an approach that will support interoperability among multiple independently sourced medical devices. Industry will require standardization to support such interoperability. Government and regulators, on behalf of the patients and in compliance with their mission to protect public health, as well as users and manufacturers require that such interoperability is safe. This complementary webinar will introduce the eHealth sector and applications, outline the challenges and risks inherent in connecting heterogeneous equipment into medical device systems, and provide insights to how manufacturers can demonstrate compliance with the rapidly changing regulatory landscape for interoperable medical devices.
This webinar was presented by UL eHealth experts on October 30, 2013.
Operational Security for Transportation: Connectivity to Rails Ashley Finden
The rail industry has a complex and novel threat model and Frank Marcus will provide an industry overview of the unique process. With a rise in connectivity between devices, it is necessary to understand what you can learn from other industries to protect your whole system.
This document provides an overview of the process improvement process, including process measurement, analysis, change, and the CMMI framework. It discusses measuring current processes to establish a baseline and analyzing processes to identify bottlenecks. Process changes are then introduced based on the analysis. The goal is to understand existing processes, relate them to models and standards, and identify constraints in order to improve quality, reduce costs and time. Process and product quality are closely linked, so improving processes enhances products.
The document summarizes key aspects of configuration management discussed in Chapter 25, including change management, version management, system building, and release management. Version management involves tracking different versions of software components to prevent interference between changes made by different developers. System building is the process of compiling and linking components to create an executable system. Release management prepares software for external distribution and tracks released system versions.
This document provides an overview of quality management in software engineering. It discusses software quality, standards, reviews, and measurements. Specifically, it covers three key areas:
1) Software quality management is concerned with ensuring software meets required quality levels through organizational processes and standards, applying quality processes at the project level, and establishing quality plans.
2) Quality management activities include independent checks on the development process and deliverables to ensure consistency with standards and goals.
3) Reviews and inspections allow groups to examine software and documentation to identify potential problems and approve progress between development stages.
This document provides an overview of project planning and estimation techniques used in software development. It discusses plan-driven and agile planning approaches. For plan-driven projects, it describes creating a detailed project plan with work breakdown, scheduling, milestones and resource allocation. It also discusses estimation techniques like experience-based estimating and algorithmic models like COCOMO. COCOMO models like application composition, early design, reuse and post-architecture are explained for estimating effort at different stages. Factors affecting accuracy and uncertainty in estimates are also covered.
This document discusses project management and risk management. It covers topics such as managing people, teamwork, risk identification, analysis, planning, monitoring, and strategies to manage common project risks like staff turnover, requirements changes, and underestimating timelines. The key aspects of software project management are planning, reporting, risk assessment, and people management to deliver software on schedule, within budget, and that meets customer expectations.
The document discusses aspect-oriented software development and key concepts in aspect-oriented programming such as aspects, join points, pointcuts, and advice. It covers how aspect-oriented programming supports separation of concerns by encapsulating cross-cutting concerns in aspects. Aspects define where advice code should be inserted via pointcuts specified at join points in the base code. This approach addresses issues like tangling and scattering that arise when implementing cross-cutting concerns in traditional object-oriented design.
This document provides an overview of embedded systems and real-time systems. It discusses embedded software characteristics including responsiveness in real-time. Common architectural patterns for embedded systems like observe and react, environmental control, and process pipeline are described. The document also covers timing analysis, real-time operating systems components, and non-stop system components to ensure continuous operation.
The document discusses service-oriented architecture (SOA) and key concepts in SOA, including:
1) SOA uses independent, reusable services as components for developing distributed systems, with services executing on different computers and communicating through standard protocols.
2) The benefits of SOA include flexibility in where services are provided and enabling inter-organizational computing through simplified information exchange.
3) Key SOA standards include SOAP for message exchange, WSDL for defining service interfaces and bindings, and WS-BPEL for defining service composition workflows.
This document provides an overview of distributed software engineering. It discusses key topics like distributed systems issues, client-server computing, and architectural patterns. Design issues for distributed systems like transparency, openness, scalability, security, and failure management are also covered. The document explains models of interaction, including remote procedure calls and message passing, and how middleware supports interaction and common services in distributed systems.
This document provides an overview of component-based software engineering (CBSE). It discusses key CBSE concepts like components, component models, CBSE processes, and component composition. Components are independent, reusable software entities with well-defined interfaces. A component model defines standards for component implementation and interoperability. CBSE processes include developing components for reuse, and developing software using existing reusable components. Middleware provides platform services to allow component communication.
The document discusses software reuse and chapter 16 of an unknown textbook. It covers several topics related to software reuse including application frameworks, software product lines, and COTS product reuse. Application frameworks provide a collection of abstract and concrete classes that can be extended and customized to create specific applications. Frameworks aim to increase reuse by providing a standardized architecture and interfaces that applications can build upon rather than developing everything from scratch. They must be extended by adding new classes and methods to create a complete application or subsystem.
This document discusses techniques for validating critical systems, including static analysis, reliability testing, and security testing. Static analysis techniques like formal verification, model checking, and automated program analysis examine source code or models without executing programs to check for errors. Reliability testing involves exercising software with test data matching actual usage to measure reliability levels. Validation costs are higher for critical systems due to additional analysis needed to ensure safety.
This document provides an overview of topics covered in Chapter 14 on Security Engineering. It discusses security engineering and how it is concerned with applying security to applications, as well as security risk assessment and designing systems based on risk assessments. The document outlines the importance of security management, as well as risk management approaches like preliminary risk assessment, life cycle risk assessment, and operational risk assessment. It also discusses designing systems for security through approaches like incorporating security into architectural design, following best practices, and minimizing vulnerabilities introduced during deployment. Finally, the document discusses system survivability and delivering essential services even when under attack.
This document discusses techniques for engineering dependable software systems. It covers redundancy and diversity approaches to achieve fault tolerance. Dependable systems are achieved through fault avoidance, detection, and tolerance. Critical systems often use regulated processes and dependable architectures like protection systems, self-monitoring architectures, and N-version programming which involve redundant and diverse components to continue operating despite failures. The document gives examples of how these techniques are applied in systems like aircraft flight control to maximize availability.
This document discusses the key aspects of system dependability, including availability, reliability, safety, and security. It notes that dependability reflects the degree to which users trust a system and defines it as covering attributes like availability, reliability, and security. It also discusses factors that influence perceptions of reliability and availability, such as usage patterns, outage length and number of users affected.
This document provides an overview of sociotechnical systems. It discusses how software systems are part of broader systems that include human, social, and organizational aspects. It describes the layers in a sociotechnical systems stack from equipment to society. Emergent properties, non-determinism, and differing views of success from stakeholders are characteristics of these complex systems. Systems engineering is the process of procuring, developing, and maintaining sociotechnical systems over their lifecycle.
This document discusses software evolution and maintenance. It covers topics like change processes, program evolution dynamics, software maintenance, and legacy system management. It notes that software change is inevitable due to new requirements, business changes, errors that need fixing, and other factors. Most software budgets are spent on evolving existing systems rather than new development. Lehman's laws describe insights into software evolution, such as the notion that change is continuous. Software maintenance involves modifying operational software to fix bugs, adapt to new environments, or add new functionality. Maintenance costs are typically higher than development costs and increase over time as software degrades.
The document provides an overview of software testing concepts including:
- The goals of testing are to validate that software meets requirements and to discover defects.
- There are different types of testing such as unit testing, component testing, and system testing that are done during development.
- Release and user testing are also discussed as later stages of the testing process.
- Key concepts covered include test-driven development, validation vs. defect testing, and strategies for effective unit testing including automated testing and partition testing.
This document discusses the design and implementation chapter of a lecture. It covers topics like using UML for object-oriented design, design patterns, and implementation issues. It then discusses the weather station case study used to illustrate the design process, including defining system context, use cases, architectural design, identifying object classes, design models, and interface specification.
The document discusses architectural design and key concepts:
- Architectural design determines the subsystems of a system and how they communicate. It represents the link between specification and design.
- Views and patterns are used to document architectures. Common views include logical, process, development, and physical views. Patterns like MVC and layered architectures organize systems.
- Architectural design involves decisions like the application architecture, distribution, styles, decomposition, and documentation. Views and non-functional requirements influence these decisions.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
3. Dependability requirements
Functional requirements to define error checking and
recovery facilities and protection against system failures.
Non-functional requirements defining the required
reliability and availability of the system.
Excluding requirements that define states and conditions
that must not arise.
3Chapter 12 Dependability and Security Specification
4. Risk-driven specification
Critical systems specification should be risk-driven.
This approach has been widely used in safety and
security-critical systems.
The aim of the specification process should be to
understand the risks (safety, security, etc.) faced by the
system and to define requirements that reduce these
risks.
4Chapter 12 Dependability and Security Specification
5. Stages of risk-based analysis
Risk identification
Identify potential risks that may arise.
Risk analysis and classification
Assess the seriousness of each risk.
Risk decomposition
Decompose risks to discover their potential root causes.
Risk reduction assessment
Define how each risk must be taken into eliminated or reduced
when the system is designed.
5Chapter 12 Dependability and Security Specification
7. Phased risk analysis
Preliminary risk analysis
Identifies risks from the systems environment. Aim is to develop
an initial set of system security and dependability requirements.
Life cycle risk analysis
Identifies risks that emerge during design and development e.g.
risks that are associated with the technologies used for system
construction. Requirements are extended to protect against
these risks.
Operational risk analysis
Risks associated with the system user interface and operator
errors. Further protection requirements may be added to cope
with these.
7Chapter 12 Dependability and Security Specification
8. Safety specification
Goal is to identify protection requirements that ensure
that system failures do not cause injury or death or
environmental damage.
Risk identification = Hazard identification
Risk analysis = Hazard assessment
Risk decomposition = Hazard analysis
Risk reduction = safety requirements specification
8Chapter 12 Dependability and Security Specification
9. Hazard identification
Identify the hazards that may threaten the system.
Hazard identification may be based on different types of
hazard:
Physical hazards
Electrical hazards
Biological hazards
Service failure hazards
Etc.
9Chapter 12 Dependability and Security Specification
10. Insulin pump risks
Insulin overdose (service failure).
Insulin underdose (service failure).
Power failure due to exhausted battery (electrical).
Electrical interference with other medical equipment
(electrical).
Poor sensor and actuator contact (physical).
Parts of machine break off in body (physical).
Infection caused by introduction of machine (biological).
Allergic reaction to materials or insulin (biological).
10Chapter 12 Dependability and Security Specification
11. Hazard assessment
The process is concerned with understanding the
likelihood that a risk will arise and the potential
consequences if an accident or incident should occur.
Risks may be categorised as:
Intolerable. Must never arise or result in an accident
As low as reasonably practical(ALARP). Must minimise the
possibility of risk given cost and schedule constraints
Acceptable. The consequences of the risk are acceptable and no
extra costs should be incurred to reduce hazard probability
11Chapter 12 Dependability and Security Specification
13. Social acceptability of risk
The acceptability of a risk is determined by human,
social and political considerations.
In most societies, the boundaries between the regions
are pushed upwards with time i.e. society is less willing
to accept risk
For example, the costs of cleaning up pollution may be less than
the costs of preventing it but this may not be socially acceptable.
Risk assessment is subjective
Risks are identified as probable, unlikely, etc. This depends on
who is making the assessment.
13Chapter 12 Dependability and Security Specification
14. Hazard assessment
Estimate the risk probability and the risk severity.
It is not normally possible to do this precisely so relative
values are used such as ‘unlikely’, ‘rare’, ‘very high’, etc.
The aim must be to exclude risks that are likely to arise
or that have high severity.
14Chapter 12 Dependability and Security Specification
15. Risk classification for the insulin pump
Identified hazard Hazard probability Accident severity Estimated risk Acceptability
1.Insulin overdose
computation
Medium High High Intolerable
2. Insulin underdose
computation
Medium Low Low Acceptable
3. Failure of
hardware monitoring
system
Medium Medium Low ALARP
4. Power failure High Low Low Acceptable
5. Machine
incorrectly fitted
High High High Intolerable
6. Machine breaks in
patient
Low High Medium ALARP
7. Machine causes
infection
Medium Medium Medium ALARP
8. Electrical
interference
Low High Medium ALARP
9. Allergic reaction Low Low Low Acceptable
15Chapter 12 Dependability and Security Specification
16. Hazard analysis
Concerned with discovering the root causes of risks in a
particular system.
Techniques have been mostly derived from safety-critical
systems and can be
Inductive, bottom-up techniques. Start with a proposed system
failure and assess the hazards that could arise from that failure;
Deductive, top-down techniques. Start with a hazard and deduce
what the causes of this could be.
16Chapter 12 Dependability and Security Specification
17. Fault-tree analysis
A deductive top-down technique.
Put the risk or hazard at the root of the tree and identify
the system states that could lead to that hazard.
Where appropriate, link these with ‘and’ or ‘or’
conditions.
A goal should be to minimise the number of single
causes of system failure.
17Chapter 12 Dependability and Security Specification
18. An example of a software fault tree
18Chapter 12 Dependability and Security Specification
19. Fault tree analysis
Three possible conditions that can lead to delivery of
incorrect dose of insulin
Incorrect measurement of blood sugar level
Failure of delivery system
Dose delivered at wrong time
By analysis of the fault tree, root causes of these
hazards related to software are:
Algorithm error
Arithmetic error
19Chapter 12 Dependability and Security Specification
20. Risk reduction
The aim of this process is to identify dependability
requirements that specify how the risks should be
managed and ensure that accidents/incidents do not
arise.
Risk reduction strategies
Risk avoidance;
Risk detection and removal;
Damage limitation.
20Chapter 12 Dependability and Security Specification
21. Strategy use
Normally, in critical systems, a mix of risk reduction
strategies are used.
In a chemical plant control system, the system will
include sensors to detect and correct excess pressure in
the reactor.
However, it will also include an independent protection
system that opens a relief valve if dangerously high
pressure is detected.
21Chapter 12 Dependability and Security Specification
22. Insulin pump - software risks
Arithmetic error
A computation causes the value of a variable to overflow or
underflow;
Maybe include an exception handler for each type of arithmetic
error.
Algorithmic error
Compare dose to be delivered with previous dose or safe
maximum doses. Reduce dose if too high.
22Chapter 12 Dependability and Security Specification
23. Examples of safety requirements
SR1: The system shall not deliver a single dose of insulin that is greater than a
specified maximum dose for a system user.
SR2: The system shall not deliver a daily cumulative dose of insulin that is greater
than a specified maximum daily dose for a system user.
SR3: The system shall include a hardware diagnostic facility that shall be
executed at least four times per hour.
SR4: The system shall include an exception handler for all of the exceptions that
are identified in Table 3.
SR5: The audible alarm shall be sounded when any hardware or software
anomaly is discovered and a diagnostic message, as defined in Table 4, shall be
displayed.
SR6: In the event of an alarm, insulin delivery shall be suspended until the user
has reset the system and cleared the alarm.
23Chapter 12 Dependability and Security Specification
24. Key points
Risk analysis is an important activity in the specification
of security and dependability requirements. It involves
identifying risks that can result in accidents or incidents.
A hazard-driven approach may be used to understand
the safety requirements for a system. You identify
potential hazards and decompose these (using methods
such as fault tree analysis) to discover their root causes.
Safety requirements should be included to ensure that
hazards and accidents do not arise or, if this is
impossible, to limit the damage caused by system
failure.
24Chapter 12 Dependability and Security Specification
25. Chapter 12 – Dependability and Security
Specification
Lecture 2
25Chapter 12 Dependability and Security Specification
26. System reliability specification
Reliability is a measurable system attribute so non-
functional reliability requirements may be specified
quantitatively. These define the number of failures that
are acceptable during normal use of the system or the
time in which the system must be available.
Functional reliability requirements define system and
software functions that avoid, detect or tolerate faults in
the software and so ensure that these faults do not lead
to system failure.
Software reliability requirements may also be included to
cope with hardware failure or operator error.
26Chapter 12 Dependability and Security Specification
27. Reliability specification process
Risk identification
Identify the types of system failure that may lead to economic
losses.
Risk analysis
Estimate the costs and consequences of the different types of
software failure.
Risk decomposition
Identify the root causes of system failure.
Risk reduction
Generate reliability specifications, including quantitative
requirements defining the acceptable levels of failure.
27Chapter 12 Dependability and Security Specification
28. Types of system failure
Failure type Description
Loss of service The system is unavailable and cannot deliver its services to
users. You may separate this into loss of critical services and
loss of non-critical services, where the consequences of a
failure in non-critical services are less than the consequences of
critical service failure.
Incorrect service delivery The system does not deliver a service correctly to users. Again,
this may be specified in terms of minor and major errors or
errors in the delivery of critical and non-critical services.
System/data corruption The failure of the system causes damage to the system itself or
its data. This will usually but not necessarily be in conjunction
with other types of failures.
28Chapter 12 Dependability and Security Specification
29. Reliability metrics
Reliability metrics are units of measurement of system
reliability.
System reliability is measured by counting the number of
operational failures and, where appropriate, relating
these to the demands made on the system and the time
that the system has been operational.
A long-term measurement programme is required to
assess the reliability of critical systems.
Metrics
Probability of failure on demand
Rate of occurrence of failures/Mean time to failure
Availability
29Chapter 12 Dependability and Security Specification
30. Probability of failure on demand (POFOD)
This is the probability that the system will fail when a
service request is made. Useful when demands for
service are intermittent and relatively infrequent.
Appropriate for protection systems where services are
demanded occasionally and where there are serious
consequence if the service is not delivered.
Relevant for many safety-critical systems with exception
management components
Emergency shutdown system in a chemical plant.
30Chapter 12 Dependability and Security Specification
31. Rate of fault occurrence (ROCOF)
Reflects the rate of occurrence of failure in the system.
ROCOF of 0.002 means 2 failures are likely in each
1000 operational time units e.g. 2 failures per 1000
hours of operation.
Relevant for systems where the system has to process a
large number of similar requests in a short time
Credit card processing system, airline booking system.
Reciprocal of ROCOF is Mean time to Failure (MTTF)
Relevant for systems with long transactions i.e. where system
processing takes a long time (e.g. CAD systems). MTTF should be
longer than expected transaction length.
31Chapter 12 Dependability and Security Specification
32. Availability
Measure of the fraction of the time that the system is
available for use.
Takes repair and restart time into account
Availability of 0.998 means software is available for 998
out of 1000 time units.
Relevant for non-stop, continuously running systems
telephone switching systems, railway signalling systems.
32Chapter 12 Dependability and Security Specification
33. Availability specification
Availability Explanation
0.9 The system is available for 90% of the time. This means that, in a
24-hour period (1,440 minutes), the system will be unavailable for
144 minutes.
0.99 In a 24-hour period, the system is unavailable for 14.4 minutes.
0.999 The system is unavailable for 84 seconds in a 24-hour period.
0.9999 The system is unavailable for 8.4 seconds in a 24-hour period.
Roughly, one minute per week.
33Chapter 12 Dependability and Security Specification
34. Failure consequences
When specifying reliability, it is not just the number of
system failures that matter but the consequences of
these failures.
Failures that have serious consequences are clearly
more damaging than those where repair and recovery is
straightforward.
In some cases, therefore, different reliability
specifications for different types of failure may be
defined.
34Chapter 12 Dependability and Security Specification
35. Over-specification of reliability
Over-specification of reliability is a situation where a
high-level of reliability is specified but it is not cost-
effective to achieve this.
In many cases, it is cheaper to accept and deal with
failures rather than avoid them occurring.
To avoid over-specification
Specify reliability requirements for different types of failure. Minor
failures may be acceptable.
Specify requirements for different services separately. Critical
services should have the highest reliability requirements.
Decide whether or not high reliability is really required or if
dependability goals can be achieved in some other way.
35Chapter 12 Dependability and Security Specification
36. Steps to a reliability specification
For each sub-system, analyse the consequences of
possible system failures.
From the system failure analysis, partition failures into
appropriate classes.
For each failure class identified, set out the reliability
using an appropriate metric. Different metrics may be
used for different reliability requirements.
Identify functional reliability requirements to reduce the
chances of critical failures.
36Chapter 12 Dependability and Security Specification
37. Insulin pump specification
Probability of failure (POFOD) is the most appropriate
metric.
Transient failures that can be repaired by user actions
such as recalibration of the machine. A relatively low
value of POFOD is acceptable (say 0.002) – one failure
may occur in every 500 demands.
Permanent failures require the software to be re-installed
by the manufacturer. This should occur no more than
once per year. POFOD for this situation should be less
than 0.00002.
37Chapter 12 Dependability and Security Specification
38. Functional reliability requirements
Checking requirements that identify checks to ensure
that incorrect data is detected before it leads to a failure.
Recovery requirements that are geared to help the
system recover after a failure has occurred.
Redundancy requirements that specify redundant
features of the system to be included.
Process requirements for reliability which specify the
development process to be used may also be included.
38Chapter 12 Dependability and Security Specification
39. Examples of functional reliability requirements
for MHC-PMS
RR1: A pre-defined range for all operator inputs shall be defined and the
system shall check that all operator inputs fall within this pre-defined range.
(Checking)
RR2:Copies of the patient database shall be maintained on two separate servers
that are not housed in the same building. (Recovery, redundancy)
RR3:N-version programming shall be used to implement the braking control
system. (Redundancy)
RR4:The system must be implemented in a safe subset of Ada and checked using
static analysis. (Process)
39Chapter 12 Dependability and Security Specification
40. Security specification
Security specification has something in common with safety
requirements specification – in both cases, your concern is to avoid
something bad happening.
Four major differences
Safety problems are accidental – the software is not operating in a
hostile environment. In security, you must assume that attackers have
knowledge of system weaknesses
When safety failures occur, you can look for the root cause or weakness
that led to the failure. When failure results from a deliberate attack, the
attacker may conceal the cause of the failure.
Shutting down a system can avoid a safety-related failure. Causing a
shut down may be the aim of an attack.
Safety-related events are not generated from an intelligent adversary.
An attacker can probe defenses over time to discover weaknesses.
40Chapter 12 Dependability and Security Specification
42. The preliminary risk assessment process for
security requirements
42Chapter 12 Dependability and Security Specification
43. Security risk assessment
Asset identification
Identify the key system assets (or services) that have to be
protected.
Asset value assessment
Estimate the value of the identified assets.
Exposure assessment
Assess the potential losses associated with each asset.
Threat identification
Identify the most probable threats to the system assets
43Chapter 12 Dependability and Security Specification
44. Security risk assessment
Attack assessment
Decompose threats into possible attacks on the system and the
ways that these may occur.
Control identification
Propose the controls that may be put in place to protect an
asset.
Feasibility assessment
Assess the technical feasibility and cost of the controls.
Security requirements definition
Define system security requirements. These can be
infrastructure or application system requirements.
44Chapter 12 Dependability and Security Specification
45. Asset analysis in a preliminary risk assessment
report for the MHC-PMS
Asset Value Exposure
The information system High. Required to support all
clinical consultations. Potentially
safety-critical.
High. Financial loss as clinics
may have to be canceled. Costs
of restoring system. Possible
patient harm if treatment cannot
be prescribed.
The patient database High. Required to support all
clinical consultations. Potentially
safety-critical.
High. Financial loss as clinics
may have to be canceled. Costs
of restoring system. Possible
patient harm if treatment cannot
be prescribed.
An individual patient record Normally low although may be
high for specific high-profile
patients.
Low direct losses but possible
loss of reputation.
45Chapter 12 Dependability and Security Specification
46. Threat and control analysis in a preliminary risk
assessment report
Threat Probability Control Feasibility
Unauthorized user
gains access as
system manager and
makes system
unavailable
Low Only allow system
management from
specific locations that are
physically secure.
Low cost of implementation but
care must be taken with key
distribution and to ensure that
keys are available in the event
of an emergency.
Unauthorized user
gains access as
system user and
accesses confidential
information
High Require all users to
authenticate themselves
using a biometric
mechanism.
Log all changes to
patient information to
track system usage.
Technically feasible but high-
cost solution. Possible user
resistance.
Simple and transparent to
implement and also supports
recovery.
46Chapter 12 Dependability and Security Specification
47. Security policy
An organizational security policy applies to all systems
and sets out what should and should not be allowed.
For example, a military policy might be:
Readers may only examine documents whose classification is
the same as or below the readers vetting level.
A security policy sets out the conditions that must be
maintained by a security system and so helps identify
system security requirements.
47Chapter 12 Dependability and Security Specification
48. Security requirements for the MHC-PMS
Patient information shall be downloaded at the start of a
clinic session to a secure area on the system client that
is used by clinical staff.
All patient information on the system client shall be
encrypted.
Patient information shall be uploaded to the database
after a clinic session has finished and deleted from the
client computer.
A log on a separate computer from the database server
must be maintained of all changes made to the system
database.
48Chapter 12 Dependability and Security Specification
49. Formal specification
Formal specification is part of a more general collection
of techniques that are known as ‘formal methods’.
These are all based on mathematical representation and
analysis of software.
Formal methods include
Formal specification;
Specification analysis and proof;
Transformational development;
Program verification.
49Chapter 12 Dependability and Security Specification
50. Use of formal methods
The principal benefits of formal methods are in reducing
the number of faults in systems.
Consequently, their main area of applicability is in critical
systems engineering. There have been several
successful projects where formal methods have been
used in this area.
In this area, the use of formal methods is most likely to
be cost-effective because high system failure costs must
be avoided.
50Chapter 12 Dependability and Security Specification
51. Specification in the software process
Specification and design are inextricably
intermingled.
Architectural design is essential to structure a
specification and the specification process.
Formal specifications are expressed in a
mathematical notation with precisely defined
vocabulary, syntax and semantics.
51Chapter 12 Dependability and Security Specification
52. Formal specification in a plan-based software
process
52Chapter 12 Dependability and Security Specification
53. Benefits of formal specification
Developing a formal specification requires the system
requirements to be analyzed in detail. This helps to detect
problems, inconsistencies and incompleteness in the
requirements.
As the specification is expressed in a formal language, it can
be automatically analyzed to discover inconsistencies and
incompleteness.
If you use a formal method such as the B method, you can
transform the formal specification into a ‘correct’ program.
Program testing costs may be reduced if the program is
formally verified against its specification.
53Chapter 12 Dependability and Security Specification
54. Acceptance of formal methods
Formal methods have had limited impact on practical
software development:
Problem owners cannot understand a formal specification and so
cannot assess if it is an accurate representation of their
requirements.
It is easy to assess the costs of developing a formal specification
but harder to assess the benefits. Managers may therefore be
unwilling to invest in formal methods.
Software engineers are unfamiliar with this approach and are
therefore reluctant to propose the use of FM.
Formal methods are still hard to scale up to large systems.
Formal specification is not really compatible with agile
development methods.
54Chapter 12 Dependability and Security Specification
55. Key points
Reliability requirements can be defined quantitatively. They include
probability of failure on demand (POFOD), rate of occurrence of
failure (ROCOF) and availability (AVAIL).
Security requirements are more difficult to identify than safety
requirements because a system attacker can use knowledge of
system vulnerabilities to plan a system attack, and can learn about
vulnerabilities from unsuccessful attacks.
To specify security requirements, you should identify the assets that
are to be protected and define how security techniques and
technology should be used to protect these assets.
Formal methods of software development rely on a system
specification that is expressed as a mathematical model. The use of
formal methods avoids ambiguity in a critical systems specification.
55Chapter 12 Dependability and Security Specification