This document summarizes a research paper on efficient real-time video transmission in wireless mesh networks. It begins with an introduction to wireless mesh networks and their benefits. It then discusses some key challenges for real-time video transmission, including unpredictable delays, packet loss, and delay jitter due to the error-prone nature of wireless links. The paper proposes a model to provide high-capacity data transfer with reduced delay for real-time video. It simulates this model using OPNET and achieves higher throughput results. Node models for the video server, receiver, access point, and FTP client/server are also described.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
Introductory Approach on Ad-hoc Networks and its Paradigms IJORCS
An ad-hoc wireless network is a collection of wireless mobile nodes that self-configure to construct a network without the need for any established infrastructure or backbone. Ad hoc networks use mobile nodes to enable communication outside wireless transmission range. With the advancement in wireless communications, more and more wireless networks appear, e.g., Mobile Ad Hoc Network (MANET), Wireless Sensor Network (WSN), etc. So, in this paper we have discussed Ad Hoc Networks along with its energy issues, applications, QoS and challenges.
Worldwide Interoperability for Microwave Access (WiMAX) is a new communication technology that
conduits the fissure between fixed and mobile access and offers the same Quality of Service (QoS) to both
types of users. Generally, WiMAX is more vulnerable to the inside and outside attacks due to the absence of
any clear line of defense. The Mobile Subscriber Stations (MSSs) selected to transfer the packets to the
Base Station (BS) are vulnerable to Denial of Service (DoS) attacks like flooding. Recent research has
discovered that DoS attacks can easily be launched by injecting malevolent management frames into the
WiMAX network based on the Privacy and Key Management- ReSPonse (PKM-RSP) and Automatic Repeat
ReQuest (ARQ)-Reset messages. In this paper, an algorithm is proposed to mitigate the flooding attacks
and enhance the security level in the network.
Enhanced Quality of Service Based Routing Protocol Using Hybrid Ant Colony Op...Editor IJCATR
The main problem of QoS routing is to setup a multicast hierarchy that may meet particular QoS constraint. In order to reduce the constraints of the earlier work a new improved technique is proposed in this work. In the proposed technique the issue of multi-cast tree is eliminated using clustering based technique. First of all multi-radio and multichannel based clustering is deployed and these cluster head are responsible
for the multicasting. It will diminish the overall energy consumption of nodes and complexity of intelligent algorithms. The path will be evaluated based upon the ant colony optimization. Thus it has produced better results than other techniques.
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
Quantative Analysis and Evaluation of Topology Control Schemes for Utilizing ...ijsrd.com
By virtue of their robustness, cost-effectiveness, self-organizing and self-configuring nature, WMNs have emerged as a new network paradigm for a wide range of applications, such as public safety and emergency response communications, intelligent transportation systems, and community networks. It is anticipated that WMNs will not only resolve the limitations of wireless ad hoc networks, local area networks (WLANs), personal area networks (WPANs), and metropolitan area networks (WMANs) but also significantly improve such networks’ performance. One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. In this paper, it is proposed to evaluate the performance of two different channel assignment schemes namely common channel assignment (CCA) and centralized tabu-based search algorithm under WCETT routing protocols for varying traffic load in terms of packet delivery ratio, throughput, average end to end delay and routing overhead using NS2 network simulator. WCETT protocol uses the weighted sum of the cumulative expected transmission time and the maximal value of efficient channels among all channels.
Introductory Approach on Ad-hoc Networks and its Paradigms IJORCS
An ad-hoc wireless network is a collection of wireless mobile nodes that self-configure to construct a network without the need for any established infrastructure or backbone. Ad hoc networks use mobile nodes to enable communication outside wireless transmission range. With the advancement in wireless communications, more and more wireless networks appear, e.g., Mobile Ad Hoc Network (MANET), Wireless Sensor Network (WSN), etc. So, in this paper we have discussed Ad Hoc Networks along with its energy issues, applications, QoS and challenges.
Worldwide Interoperability for Microwave Access (WiMAX) is a new communication technology that
conduits the fissure between fixed and mobile access and offers the same Quality of Service (QoS) to both
types of users. Generally, WiMAX is more vulnerable to the inside and outside attacks due to the absence of
any clear line of defense. The Mobile Subscriber Stations (MSSs) selected to transfer the packets to the
Base Station (BS) are vulnerable to Denial of Service (DoS) attacks like flooding. Recent research has
discovered that DoS attacks can easily be launched by injecting malevolent management frames into the
WiMAX network based on the Privacy and Key Management- ReSPonse (PKM-RSP) and Automatic Repeat
ReQuest (ARQ)-Reset messages. In this paper, an algorithm is proposed to mitigate the flooding attacks
and enhance the security level in the network.
Enhanced Quality of Service Based Routing Protocol Using Hybrid Ant Colony Op...Editor IJCATR
The main problem of QoS routing is to setup a multicast hierarchy that may meet particular QoS constraint. In order to reduce the constraints of the earlier work a new improved technique is proposed in this work. In the proposed technique the issue of multi-cast tree is eliminated using clustering based technique. First of all multi-radio and multichannel based clustering is deployed and these cluster head are responsible
for the multicasting. It will diminish the overall energy consumption of nodes and complexity of intelligent algorithms. The path will be evaluated based upon the ant colony optimization. Thus it has produced better results than other techniques.
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
MOBILE IP ON MOBILE AD HOC NETWORKS: AN IMPLEMENTATION AND PERFORMANCE EVALUA...acijjournal
Mobile computing devices equipped with transceivers form Mobile Ad Hoc Networks (MANET), when two
or more of these devices find themselves within transmission range. MANETs are stand-alone (no existing
infrastructure needed), autonomous networks that utilise multi-hop communication to reach nodes out of
transmitter range. Unlike infrastructure networks e.g. the Internet with fixed topology, MANETs are
dynamic. Despite the heterogeneous nature of these two networks, integrating MANETs with the Internet
extends the network coverage area of the Internet, and adds to the application domain of MANETs. One of
the many ways of combining MANETs with the Internet, is the use of Mobile Internet Protocol (Mobile IP)
alongside a MANET routing protocol, to route packets between the Internet and the MANET, via Gateway
agents. In this paper, we evaluate the performance of Mobile IP on MANET in Network Simulator 2 (NS2).
We have implemented Mobile IP on Ad hoc On-demand Distance Vector (AODV), Ad hoc On-demand
Multiple Distance Vector (AOMDV) and Destination-Sequenced Distance Vector (DSDV) routing
protocols, and compared performances based on Throughput, End-to-End Delay (E2ED), Packet Delivery
Ratio (PDR) and Normalized Packet Ratio (NPR). The simulation results suggest that, on-demand routing
within the MANET better serves Mobile IP on MANETs.
MULTI-HOP BANDWIDTH MANAGEMENT PROTOCOL FOR MOBILE AD HOC NETWORKSIJMIT JOURNAL
An admission control scheme should play the role of a coordinator for flows in a data communication network, to provide the guarantees as the medium is shared. The nodes of a wired network can monitor the medium to know the available bandwidth at any point of time. But, in wireless ad hoc networks, a node must consume the bandwidth of neighboring nodes, during a communication. Hence, the consumption of bandwidth by a flow and the availability of resources to any wireless node strictly depend upon the neighboring nodes within its transmission range. We present a scalable and efficient admission control scheme, Multi-hop Bandwidth Management Protocol (MBMP), to support the QoS requirements
in multi-hop ad hoc networks. We simulate several options to design MBMP and compare the performances of these options through mathematical analysis and simulation results, and compare its effectiveness with the existing admission control schemes through extensive simulations.
Dynamic Hybrid Topology Design for Integrated Traffic Support in WDM Mesh Net...CSCJournals
The future Internet will require the transport of a wide range of services including high bandwidth one-to-many applications, with a dynamic interconnection of devices. WDM layer support realizes such services in a transparent, reliable and efficient way. Most of the recent studies have been focused on efficiently building and configuring light-paths for unicast or light-trees for multicast in isolation, and do not take existing traffic demands and configuration into consideration. In this paper we consider a dynamic design problem of integrated traffic in a realistic WDM mesh network. In such a network, new traffic demands of either multicast and/or unicast are supported dynamically in the presence of an existing mixture of traffic. The amount of bandwidth per wavelength is abundant, while the wavelengths and light splitting capabilities on WDM switches are limited. Using subwavelength sharing among traffic demands of unicast and multicast, we build a hybrid virtual topology that exploits both existing light-trees and light-paths. By optimizing WDM resources in addition to resource sharing with existing unicast and multicast demands, we truly maximize the WDM layer capability and efficiently support more traffic demands. We validate the efficiency of our approach with extensive simulations on various network topologies.
AN ADAPTIVE DIFFSERV APPROACH TO SUPPORT QOS IN NETWORK MOBILITY NEMO ENVIRON...IJCNCJournal
Network Mobility Basic Support (NEMO BS) protocol (RFC 3963) is an extension of Mobile IPv6. The NEMO BS embraced by IETF working group to permit any node in the portable network to be accessible to the Internet despite the fact the network itself is roaming. This protocol likewise Mobile IPv6 doesn’t deliver any kind of Quality of Service (QoS) guarantees to its clients. It can barely offer the same level of services (i.e. Best-Effort) to all the users without obligation to the application’s needs. This propositions a challenge to real-time applications that demand a precise level of QoS pledge. The Differentiated Services has recently come to be the most widely used QoS support technology in IP networks due to its relative simplicity and scalability benefits. This paper proposes a new scheme to provide QoS to mobile network nodes within NEMO context. The proposed scheme intends to reduce handover latency for the users of MNN as well as alleviates packet losses. The feasibility of the proposed enhancement is assessed by measuring its performance against the native NEMO BS standard protocol using NS-2 simulator. The obtained results in the simulation study have demonstrated that the proposed scheme outperforms the standard NEMO BS protocol.
A Secure QOS Distributed Routing Protocol for Hybrid Wireless Networksiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Security Enhancement in AODV Routing Protocol for MANETsidescitation
Adhoc networks are a new wireless networking paradigm for mobile hosts.
Mobile Ad-hoc Networks (MANETs) are wireless networks with absence of infrastructure
centralized support. Routing in MANETs is challenging task due to mobility of nodes.
Several routing protocols have been developed for Mobile Ad-hoc Networks. This paper
describes concept of security enhancement in AODV routing protocol by detection and
tolerance of attacks using secure message transmission (SMT) protocol. Present AODV
routing protocol is not secure by malicious nodes. One main challenge in design of these
networks is their vulnerability to security attacks. In this paper we study how to make node
malicious and at same we will detect malicious node in AODV protocol using Network
Simulator-2(NS-2) tool.
A Survey of Various Routing and Channel Assignment Strategies for MR-MC WMNsijsrd.com
One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.
MOBILE IP ON MOBILE AD HOC NETWORKS: AN IMPLEMENTATION AND PERFORMANCE EVALUA...acijjournal
Mobile computing devices equipped with transceivers form Mobile Ad Hoc Networks (MANET), when two
or more of these devices find themselves within transmission range. MANETs are stand-alone (no existing
infrastructure needed), autonomous networks that utilise multi-hop communication to reach nodes out of
transmitter range. Unlike infrastructure networks e.g. the Internet with fixed topology, MANETs are
dynamic. Despite the heterogeneous nature of these two networks, integrating MANETs with the Internet
extends the network coverage area of the Internet, and adds to the application domain of MANETs. One of
the many ways of combining MANETs with the Internet, is the use of Mobile Internet Protocol (Mobile IP)
alongside a MANET routing protocol, to route packets between the Internet and the MANET, via Gateway
agents. In this paper, we evaluate the performance of Mobile IP on MANET in Network Simulator 2 (NS2).
We have implemented Mobile IP on Ad hoc On-demand Distance Vector (AODV), Ad hoc On-demand
Multiple Distance Vector (AOMDV) and Destination-Sequenced Distance Vector (DSDV) routing
protocols, and compared performances based on Throughput, End-to-End Delay (E2ED), Packet Delivery
Ratio (PDR) and Normalized Packet Ratio (NPR). The simulation results suggest that, on-demand routing
within the MANET better serves Mobile IP on MANETs.
MULTI-HOP BANDWIDTH MANAGEMENT PROTOCOL FOR MOBILE AD HOC NETWORKSIJMIT JOURNAL
An admission control scheme should play the role of a coordinator for flows in a data communication network, to provide the guarantees as the medium is shared. The nodes of a wired network can monitor the medium to know the available bandwidth at any point of time. But, in wireless ad hoc networks, a node must consume the bandwidth of neighboring nodes, during a communication. Hence, the consumption of bandwidth by a flow and the availability of resources to any wireless node strictly depend upon the neighboring nodes within its transmission range. We present a scalable and efficient admission control scheme, Multi-hop Bandwidth Management Protocol (MBMP), to support the QoS requirements
in multi-hop ad hoc networks. We simulate several options to design MBMP and compare the performances of these options through mathematical analysis and simulation results, and compare its effectiveness with the existing admission control schemes through extensive simulations.
Dynamic Hybrid Topology Design for Integrated Traffic Support in WDM Mesh Net...CSCJournals
The future Internet will require the transport of a wide range of services including high bandwidth one-to-many applications, with a dynamic interconnection of devices. WDM layer support realizes such services in a transparent, reliable and efficient way. Most of the recent studies have been focused on efficiently building and configuring light-paths for unicast or light-trees for multicast in isolation, and do not take existing traffic demands and configuration into consideration. In this paper we consider a dynamic design problem of integrated traffic in a realistic WDM mesh network. In such a network, new traffic demands of either multicast and/or unicast are supported dynamically in the presence of an existing mixture of traffic. The amount of bandwidth per wavelength is abundant, while the wavelengths and light splitting capabilities on WDM switches are limited. Using subwavelength sharing among traffic demands of unicast and multicast, we build a hybrid virtual topology that exploits both existing light-trees and light-paths. By optimizing WDM resources in addition to resource sharing with existing unicast and multicast demands, we truly maximize the WDM layer capability and efficiently support more traffic demands. We validate the efficiency of our approach with extensive simulations on various network topologies.
AN ADAPTIVE DIFFSERV APPROACH TO SUPPORT QOS IN NETWORK MOBILITY NEMO ENVIRON...IJCNCJournal
Network Mobility Basic Support (NEMO BS) protocol (RFC 3963) is an extension of Mobile IPv6. The NEMO BS embraced by IETF working group to permit any node in the portable network to be accessible to the Internet despite the fact the network itself is roaming. This protocol likewise Mobile IPv6 doesn’t deliver any kind of Quality of Service (QoS) guarantees to its clients. It can barely offer the same level of services (i.e. Best-Effort) to all the users without obligation to the application’s needs. This propositions a challenge to real-time applications that demand a precise level of QoS pledge. The Differentiated Services has recently come to be the most widely used QoS support technology in IP networks due to its relative simplicity and scalability benefits. This paper proposes a new scheme to provide QoS to mobile network nodes within NEMO context. The proposed scheme intends to reduce handover latency for the users of MNN as well as alleviates packet losses. The feasibility of the proposed enhancement is assessed by measuring its performance against the native NEMO BS standard protocol using NS-2 simulator. The obtained results in the simulation study have demonstrated that the proposed scheme outperforms the standard NEMO BS protocol.
A Secure QOS Distributed Routing Protocol for Hybrid Wireless Networksiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Security Enhancement in AODV Routing Protocol for MANETsidescitation
Adhoc networks are a new wireless networking paradigm for mobile hosts.
Mobile Ad-hoc Networks (MANETs) are wireless networks with absence of infrastructure
centralized support. Routing in MANETs is challenging task due to mobility of nodes.
Several routing protocols have been developed for Mobile Ad-hoc Networks. This paper
describes concept of security enhancement in AODV routing protocol by detection and
tolerance of attacks using secure message transmission (SMT) protocol. Present AODV
routing protocol is not secure by malicious nodes. One main challenge in design of these
networks is their vulnerability to security attacks. In this paper we study how to make node
malicious and at same we will detect malicious node in AODV protocol using Network
Simulator-2(NS-2) tool.
A Survey of Various Routing and Channel Assignment Strategies for MR-MC WMNsijsrd.com
One fundamental problem of WMNs with a limited number of radio interfaces and orthogonal channels is that the performance degrades significantly as the network size grows. This results from increased interference between nodes and diminished spatial reuse over the network. A WMN node needs to share a common channel with each of its neighbours in the communication range, requiring it to set up a virtual link. Moreover, to reduce network interference, a node should minimize the number of neighbours that it shares a common channel with. The objective of a channel assignment strategy is to ensure efficient utilization of the available channels (e.g., by minimizing interference) while maximizing connectivity in the network. However, since these two requirements are conflicting with each other, the goal is to achieve a balance between these two. The major constraints which need to be satisfied by a channel assignment scheme include fixed number of channels in the network, limited number of radios in mesh nodes, common channel between two communicating nodes, and limited channel capacity. Also, a channel assignment scheme should take the amount of traffic load supported by each mesh node into consideration.
Implementation of Vertical Handoff Algorithm between IEEE 802.11 WLAN & CDMA ...IOSR Journals
Abstract : Wireless communications is the fastest growing segment of the communications industry. Everyone wants the quality of services anytime & anywhere. Wireless networks can integrate various heterogeneous radio access technologies as GSM, WLAN, Wimax etc. WiMAX is an IP based, wireless broadband access technology that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access (WiMAX). The main promise of interconnecting these heterogeneous networks is to provide high performance in achieving a high data rate and support real time applications. These services require various networks (such as CDMA2000 and Wireless LAN) to be integrated into IP-based networks, which further require a seamless vertical handoff to 4th generation wireless networks. When a mobile host (MH) changes its point of attachment, its IP address gets changed. MH should be able to maintain all the existing connections using the new IP address. This process of changing a connection from one IP address to another one in IP network is called handoff. Vertical handoff is switching from one network to another while maintaining the session. Vertical Handoff (VHO) is a major concern for different heterogeneous networks. VHO can be user requested or based on some criteria already designed by the researcher of that particular algorithm. The main objective is to implement efficient & effective handoff scheme between two heterogeneous network ie. 802.11 WLAN & CDMA. Keywords - CDMA , 4G, Vertical Handoff, WLAN
Implementation of Vertical Handoff Algorithm between IEEE 802.11 WLAN & CDMA ...IOSR Journals
Wireless communications is the fastest growing segment of the communications industry. Everyone
wants the quality of services anytime & anywhere. Wireless networks can integrate various heterogeneous radio
access technologies as GSM, WLAN, Wimax etc. WiMAX is an IP based, wireless broadband access technology
that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of
cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access
(WiMAX). The main promise of interconnecting these heterogeneous networks is to provide high performance in
achieving a high data rate and support real time applications. These services require various networks (such as
CDMA2000 and Wireless LAN) to be integrated into IP-based networks, which further require a seamless
vertical handoff to 4th generation wireless networks. When a mobile host (MH) changes its point of attachment,
its IP address gets changed. MH should be able to maintain all the existing connections using the new IP
address. This process of changing a connection from one IP address to another one in IP network is called
handoff. Vertical handoff is switching from one network to another while maintaining the session. Vertical
Handoff (VHO) is a major concern for different heterogeneous networks. VHO can be user requested or based
on some criteria already designed by the researcher of that particular algorithm. The main objective is to
implement efficient & effective handoff scheme between two heterogeneous network ie. 802.11 WLAN &
CDMA
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Wireless Mesh Networks Based on MBPSO Algorithm to Improvement Throughput IJECEIAES
Wireless Mesh Networks can be regarded as a type of communication technology in mesh topology in which wireless nodes interconnect with one another. Wireless Mesh Networks depending on the semi-static configuration in different paths among nodes such as PDR, E2E delay and throughput. This study summarized different types of previous heuristic algorithms in order to adapt with proper algorithm that could solve the issue. Therefore, the main objective of this study is to determine the proper methods, approaches or algorithms that should be adapted to improve the throughput. A Modified Binary Particle Swarm Optimization (MBPSO) approach was adapted to improvements the throughput. Finally, the finding shows that throughput increased by 5.79% from the previous study.
A wireless mesh network is a decentralized network where nodes communicate wirelessly, forming a web-like structure. It enables efficient data transmission and extends coverage by relaying signals through interconnected nodes.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
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WiMax offers some advantages over WiFi.WiMax is the real wireless architecture by which the wireless access range can extended to 49.6Kms compared with Wi-Fi 91mts and Bluetooth’s 9mts. WiMax used to provide connectivity to entire cities, and may be incorporated into laptops to give users an added measure of mobility.
Help the Genetic Algorithm to Minimize the Urban Traffic on IntersectionsIJORCS
Control of traffic lights at the intersections of the main issues is the optimal traffic. Intersections to regulate traffic flow of vehicles and eliminate conflicting traffic flows are used. Modeling and simulation of traffic are widely used in industry. In fact, the modeling and simulation of an industrial system is studied before creating economically and when it is affordable. The aim of this article is a smart way to control traffic. The first stage of the project with the objective of collecting statistical data (cycle time of each of the intersection of the lights of vehicles is waiting for a red light) steps where the data collection found optimal amounts next it is. Introduced by genetic algorithm optimization of parameters is performed. GA begin with coding step as a binary variable (the range specified by the initial data set is obtained) will start with an initial population and then a new generation of genetic operators mutation and crossover and will Finally, the members of the optimal fitness values are selected as the solution set. The optimal output of Petri nets CPN TOOLS modeling and software have been implemented. The results indicate that the performance improvement project in intersections traffic control systems. It is known that other data collected and enforced intersections of evolutionary methods such as genetic algorithms to reduce the waiting time for traffic lights behind the red lights and to determine the appropriate cycle.
Welcoming the research scholars, scientists around the globe in the Open Access Dimension, IJORCS is now accepting manuscripts for its next issue (Volume 4, Issue 4). Authors are encouraged to contribute to the research community by submitting to IJORCS, articles that clarify new research results, projects, surveying works and industrial experiences that describe significant advances in field of computer science.
All paper submissions (http://www.ijorcs.org/submit-paper) are received and managed electronically by IJORCS Team. Detailed instructions about the submission procedure are available on IJORCS website (http://www.ijorcs.org/author-guidelines)
License plate recognition system is one of the core technologies in intelligent traffic control. In this paper, a new and tunable algorithm which can detect multiple license plates in high resolution applications is proposed. The algorithm aims at investigation into and identification of the novel Iranian and some European countries plate, characterized by both inclusion of blue area on it and its geometric shape. Obviously, the suggested algorithm contains suitable velocity due to not making use of heavy pre-processing operation such as image-improving filters, edge-detection operation and omission of noise at the beginning stages. So, the recommended method of ours is compatible with model-adaptation, i.e., the very blue section of the plate so that the present method indicated the fact that if several plates are included in the image, the method can successfully manage to detect it. We evaluated our method on the two Persian single vehicle license plate data set that we obtained 99.33, 99% correct recognition rate respectively. Further we tested our algorithm on the Persian multiple vehicle license plate data set and we achieved 98% accuracy rate. Also we obtained approximately 99% accuracy in character recognition stage.
FPGA Implementation of FIR Filter using Various Algorithms: A RetrospectiveIJORCS
This Paper is a review study of FPGA implementation of Finite Impulse response (FIR) with low cost and high performance. The key observation of this paper is an elaborate analysis about hardware implementations of FIR filters using different algorithm i.e., Distributed Arithmetic (DA), DA-Offset Binary Coding (DA-OBC), Common Sub-expression Elimination (CSE) and sum-of-power-of-two (SOPOT) with less resources and without affecting the performance of the original FIR Filter.
Using Virtualization Technique to Increase Security and Reduce Energy Consump...IJORCS
An approach has been presented in this paper in order to generate a secure environment on internet Based Virtual Computing platform and also to reduce energy consumption in green cloud computing. The proposed approach constantly checks the accuracy of stored data by means of a central control service inside the network environment and also checks system security through isolating single virtual machines using a common virtual environment. This approach has been simulated on two types of Virtual Machine Manager (VMM) Quick EMUlator (Qemu), HVM (Hardware Virtual Machine) Xen and outputs of the simulation in VMInsight show that when service is getting singly used, the overhead of its performance will be increased. As a secure system, the proposed approach is able to recognize malicious behaviors and assure service security by means of operational integrity measurement. Moreover, the rate of system efficiency has been evaluated according to the amount of energy consumption on five applications (Defragmentation, Compression, Linux Boot Decompression and Kernel Boot). Therefore, this has been resulted that to secure multi-tenant environment, managers and supervisors should independently install a security monitoring system for each Virtual Machines (VMs) which will come up to have the management heavy workload of. While the proposed approach, can respond to all VM’s with just one virtual machine as a supervisor.
Algebraic Fault Attack on the SHA-256 Compression FunctionIJORCS
The cryptographic hash function SHA-256 is one member of the SHA-2 hash family, which was proposed in 2000 and was standardized by NIST in 2002 as a successor of SHA-1. Although the differential fault attack on SHA-1compression function has been proposed, it seems hard to be directly adapted to SHA-256. In this paper, an efficient algebraic fault attack on SHA-256 compression function is proposed under the word-oriented random fault model. During the attack, an automatic tool STP is exploited, which constructs binary expressions for the word-based operations in SHA-256 compression function and then invokes a SAT solver to solve the equations. The simulation of the new attack needs about 65 fault injections to recover the chaining value and the input message block with about 200 seconds on average. Moreover, based on the attack on SHA-256 compression function, an almost universal forgery attack on HMAC-SHA-256 is presented. Our algebraic fault analysis is generic, automatic and can be applied to other ARX-based primitives.
Enhancement of DES Algorithm with Multi State LogicIJORCS
The principal goal to design any encryption algorithm must be the security against unauthorized access or attacks. Data Encryption Standard algorithm is a symmetric key algorithm and it is used to secure the data. Enhanced DES algorithm works on increasing the key length or complex S-BOX design or increased the number of states in which the information is to be represented or combination of above criteria. By increasing the key length, the number of combinations for key will increase which is hard for the intruder to do the brute force attack. As the S-BOX design will become the complex there will be a good avalanche effect. As the number of states increases in which the information is represented, it is hard for the intruder to crack the actual information. Proposed algorithm replace the predefined XOR operation applied during the 16 round of the standard algorithm by a new operation called “Hash function” depends on using two keys. One key used in “F” function and another key consists of a combination of 16 states (0,1,2…13,14,15) instead of the ordinary 2 state key (0, 1). This replacement adds a new level of protection strength and more robustness against breaking methods.
Hybrid Simulated Annealing and Nelder-Mead Algorithm for Solving Large-Scale ...IJORCS
This paper presents a new algorithm for solving large scale global optimization problems based on hybridization of simulated annealing and Nelder-Mead algorithm. The new algorithm is called simulated Nelder-Mead algorithm with random variables updating (SNMRVU). SNMRVU starts with an initial solution, which is generated randomly and then the solution is divided into partitions. The neighborhood zone is generated, random number of partitions are selected and variables updating process is starting in order to generate a trail neighbor solutions. This process helps the SNMRVU algorithm to explore the region around a current iterate solution. The Nelder- Mead algorithm is used in the final stage in order to improve the best solution found so far and accelerates the convergence in the final stage. The performance of the SNMRVU algorithm is evaluated using 27 scalable benchmark functions and compared with four algorithms. The results show that the SNMRVU algorithm is promising and produces high quality solutions with low computational costs.
Welcoming the research scholars, scientists around the globe in the Open Access Dimension, IJORCS is now accepting manuscripts for its next issue (Volume 4, Issue 2). Authors are encouraged to contribute to the research community by submitting to IJORCS, articles that clarify new research results, projects, surveying works and industrial experiences that describe significant advances in field of computer science.
To view complete list of topics coverage of IJORCS, Aim & Scope, please visit, www.ijorcs.org/scope
Welcoming the research scholars, scientists around the globe in the Open Access Dimension, IJORCS is now accepting manuscripts for its next issue (Volume 4, Issue 1). Authors are encouraged to contribute to the research community by submitting to IJORCS, articles that clarify new research results, projects, surveying works and industrial experiences that describe significant advances in field of computer science.
Voice Recognition System using Template MatchingIJORCS
It is easy for human to recognize familiar voice but using computer programs to identify a voice when compared with others is a herculean task. This is due to the problem that is encountered when developing the algorithm to recognize human voice. It is impossible to say a word the same way in two different occasions. Human speech analysis by computer gives different interpretation based on varying speed of speech delivery. This research paper gives detail description of the process behind implementation of an effective voice recognition algorithm. The algorithm utilize discrete Fourier transform to compare the frequency spectra of two voice samples because it remained unchanged as speech is slightly varied. Chebyshev inequality is then used to determine whether the two voices came from the same person. The algorithm is implemented and tested using MATLAB.
Channel Aware Mac Protocol for Maximizing Throughput and FairnessIJORCS
The proper channel utilization and the queue length aware routing protocol is a challenging task in MANET. To overcome this drawback we are extending the previous work by improving the MAC protocol to maximize the Throughput and Fairness. In this work we are estimating the channel condition and Contention for a channel aware packet scheduling and the queue length is also calculated for the routing protocol which is aware of the queue length. The channel is scheduled based on the channel condition and the routing is carried out by considering the queue length. This queue length will provide a measurement of traffic load at the mobile node itself. Depending upon this load the node with the lesser load will be selected for the routing; this will effectively balance the load and improve the throughput of the ad hoc network.
A Review and Analysis on Mobile Application Development Processes using Agile...IJORCS
Over a last decade, mobile telecommunication industry has observed a rapid growth, proved to be highly competitive, uncertain and dynamic environment. Besides its advancement, it has also raised number of questions and gained concern both in industry and research. The development process of mobile application differs from traditional softwares as the users expect same features similar to their desktop computer applications with additional mobile specific functionalities. Advanced mobile applications require assimilation with existing enterprise computing systems such as databases, legacy applications and Web services. In addition, the lifecycle of a mobile application moves much faster than that of a traditional Web application and therefore the lifecycle management associated therein must be adjusted accordingly. The Security and application testing are more stimulating and interesting in mobile application than in Web applications since the technology in mobile devices progresses rapidly and developers must stay in touch with the latest developments, news and trends in their area of work. With the rising competence of software market, researchers are seeking more flexible methods that can adjust to dynamic situations where software system requirements are changing over time, producing valuable software in short duration and within low budget. The intrinsic uncertainty and complexity in any software project therefore requires an iterative developmental plan to cope with uncertainty and a large number of unknown variables. Agile Methodologies were thus introduced to meet the new requirements of the software development companies. The agile methodologies aim at facilitating software development processes where changes are acceptable at any stage and provide a structure for highly collaborative software development. Therefore, the present paper aims in reviewing and analysing different prevalent methodologies utilizing agile techniques that are currently in use for the development of mobile applications. This paper provides a detailed review and analysis on the use of agile methodologies in the proposed processes associated with mobile application skills and highlights its benefit and constraints. In addition, based on this analysis, future research needs are identified and discussed.
Congestion Prediction and Adaptive Rate Adjustment Technique for Wireless Sen...IJORCS
In general, nodes in Wireless Sensor Networks (WSNs) are equipped with limited battery and computation capabilities but the occurrence of congestion consumes more energy and computation power by retransmitting the data packets. Thus, congestion should be regulated to improve network performance. In this paper, we propose a congestion prediction and adaptive rate adjustment technique for Wireless Sensor Networks. This technique predicts congestion level using fuzzy logic system. Node degree, data arrival rate and queue length are taken as inputs to the fuzzy system and congestion level is obtained as an outcome. When the congestion level is amidst moderate and maximum ranges, adaptive rate adjustment technique is triggered. Our technique prevents congestion by controlling data sending rate and also avoids unsolicited packet losses. By simulation, we prove the proficiency our technique. It increases system throughput and network performance significantly.
A Study of Routing Techniques in Intermittently Connected MANETsIJORCS
A Mobile Ad hoc Network (MANET) is a self-configuring infrastructure less network of mobile devices connected by wireless. These are a kind of wireless Ad hoc Networks that usually has a routable networking environment on top of a Link Layer Ad hoc Network. The routing approach in MANET includes mainly three categories viz., Reactive Protocols, Proactive Protocols and Hybrid Protocols. These traditional routing schemes are not pertinent to the so called Intermittently Connected Mobile Ad hoc Network (ICMANET). ICMANET is a form of Delay Tolerant Network, where there never exists a complete end – to – end path between two nodes wishing to communicate. The intermittent connectivity araise when network is sparse or highly mobile. Routing in such a spasmodic environment is arduous. In this paper, we put forward the indication of prevailing routing approaches for ICMANET with their benefits and detriments
Improving the Efficiency of Spectral Subtraction Method by Combining it with ...IJORCS
In the field of speech signal processing, Spectral subtraction method (SSM) has been successfully implemented to suppress the noise that is added acoustically. SSM does reduce the noise at satisfactory level but musical noise is a major drawback of this method. To implement spectral subtraction method, transformation of speech signal from time domain to frequency domain is required. On the other hand, Wavelet transform displays another aspect of speech signal. In this paper we have applied a new approach in which SSM is cascaded with wavelet thresholding technique (WTT) for improving the quality of speech signal by removing the problem of musical noise to a great extent. Results of this proposed system have been simulated on MATLAB.
An Adaptive Load Sharing Algorithm for Heterogeneous Distributed SystemIJORCS
Due to the restriction of designing faster and faster computers, one has to find the ways to maximize the performance of the available hardware. A distributed system consists of several autonomous nodes, where some nodes are busy with processing, while some nodes are idle without any processing. To make better utilization of the hardware, the tasks or load of the overloaded node will be sent to the under loaded node that has less processing weight to minimize the response time of the tasks. Load balancing is a tool used effectively for balancing the load among the systems. Dynamic load balancing takes into account of the current system state for migration of the tasks from heavily loaded nodes to the lightly loaded nodes. In this paper, we devised an adaptive load-sharing algorithm to balance the load by taking into consideration of connectivity among the nodes, processing capacity of each node and link capacity.
The Design of Cognitive Social Simulation Framework using Statistical Methodo...IJORCS
Modeling the behavior of the cognitive architecture in the context of social simulation using statistical methodologies is currently a growing research area. Normally, a cognitive architecture for an intelligent agent involves artificial computational process which exemplifies theories of cognition in computer algorithms under the consideration of state space. More specifically, for such cognitive system with large state space the problem like large tables and data sparsity are faced. Hence in this paper, we have proposed a method using a value iterative approach based on Q-learning algorithm, with function approximation technique to handle the cognitive systems with large state space. From the experimental results in the application domain of academic science it has been verified that the proposed approach has better performance compared to its existing approaches.
An Enhanced Framework for Improving Spatio-Temporal Queries for Global Positi...IJORCS
To efficiently process continuous spatio-temporal queries, we need to efficiently and effectively handle large number of moving objects and continuous updates on these queries. In this paper, we propose a framework that employs a new indexing algorithm that is built on top of SQL Server 2008 and avoid the overhead related to R-Tree indexing. To answer range queries, we utilize dynamic materialized view concept to efficiently handle update queries. We propose an adaptive safe region to reduce communication costs between the client and the server and to minimize position update load. Caching of results was utilized to enhance the overall performance of the framework. To handle concurrent spatio-temporal queries, we utilize publish/subscribe paradigm to group similar queries and efficiently process these requests. Experiments show that the overall proposed framework performance was able to outperform R-Tree index and produce promising and satisfactory results.
A PSO-Based Subtractive Data Clustering AlgorithmIJORCS
There is a tremendous proliferation in the amount of information available on the largest shared information source, the World Wide Web. Fast and high-quality clustering algorithms play an important role in helping users to effectively navigate, summarize, and organize the information. Recent studies have shown that partitional clustering algorithms such as the k-means algorithm are the most popular algorithms for clustering large datasets. The major problem with partitional clustering algorithms is that they are sensitive to the selection of the initial partitions and are prone to premature converge to local optima. Subtractive clustering is a fast, one-pass algorithm for estimating the number of clusters and cluster centers for any given set of data. The cluster estimates can be used to initialize iterative optimization-based clustering methods and model identification methods. In this paper, we present a hybrid Particle Swarm Optimization, Subtractive + (PSO) clustering algorithm that performs fast clustering. For comparison purpose, we applied the Subtractive + (PSO) clustering algorithm, PSO, and the Subtractive clustering algorithms on three different datasets. The results illustrate that the Subtractive + (PSO) clustering algorithm can generate the most compact clustering results as compared to other algorithms.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
2. 12 Rajanikanth Aluvalu, NitinBirari, Supriya Byreddy
APs[3]. The drawback of this solution is highly 2. Classification of multihop wireless networks:
expensive infrastructure costs, since an expensive
cabled connection to the wired Internet backbone is
necessary for each AP. On the other hand, constructing
a wireless mesh network decreases the infrastructure
costs, since the mesh network requires only a few
points of connection to the wired network. Hence,
WMNs can enable rapid implementation and possible
modifications of the network at a reasonable cost,
which is extremely important in today’s competitive
market place. Currently, the data rates of wireless
local-area networks (WLANs) have been increased,
e.g., 54 Mbps for 802.11a and 802.11g, by utilizing
spectrally efficient modulation schemes [5]. Although
Fig. 2: Classification of multihop wireless networks
the data rates of WLANs are increasing, for a specific
transmission power, the coverage and connectivity of
Fig. 2 shows the classification of multihop wireless
WLANs decrease as the end-user becomes further
networks; these constitute the category of wireless
from the access point. Multi-hop and multi-channel
networks that primarily use multihop wireless relaying.
communications among mesh routers and long
The major categories in the multihop wireless
transmission range of WiMAX towers deployed in
networks are the ad hoc wireless networks, WMNs,
WMNs can enable long-distance communication
wireless sensor networks, and hybrid wireless
without any significant performance degradation.
networks. This book mainly focuses on WMNs. Ad
Wireless mesh networks are dynamically self-
hoc wireless networks [2] mainly lack in infrastructure
organized and self-configured. In other words, the
having highly dynamic topology. Wireless sensor
mesh clients and routers automatically establish and
networks, formed by tiny sensor nodes that can gather
maintain network connectivity, which enables
physical parameters and transmit to a central
seamless multi-hop interconnection service [3]. For
monitoring node, can use either single-hop wireless
example, when new nodes are added into the network,
communication or a multihop wireless relaying.
these nodes utilize their meshing functionalities to
Hybrid wireless networks utilize [3] both single- and
discover all possible routers and determine the optimal
multihop communications simultaneously within the
paths to the wired Internet. Furthermore, the existing
traditionally single-hop wireless networks such as
mesh routers reorganize the network considering the
cellular networks and wireless in local loops (WiLL).
newly available routes and hence; the network can be
WMNs use multihop wireless relaying over a partial
easily expanded. Mesh routers are resource-rich nodes
mesh topology for its communication. The primary
equipped with high processing and memory
differences between these two types of networks are
capabilities, while mesh clients have limited memory
mobility of nodes and network topology. Wireless ad
and computational power.
hoc networks are high mobility networks where the
network topology changes dynamically. On the other
hand, WMNs do have a relatively static network with
most relay nodes fixed. Therefore, the network
mobility of WMNs is very low in comparison with
wireless ad hoc networks.
B. Real time Video
Real time video at sender’s side is video that is
being transmitted live and at receiver’s side, is being
watched live. Video technologies are improving
dramatically and rapidly, supporting mobile and
ubiquitous real-time video experiences [8]. Low cost,
simple platforms for real-time video will become an
essential part of the way we communicate with each
other, and will spawn the next generation of consumer
behavior, business practice, media culture and
economics, and innovation policy.
Today, many devices are able to conduct live video
communications, and many more are in the pipeline
Fig.1: Wireless mesh network architecture
www.ijorcs.org
3. Efficient real-time Video Transmission in Wireless Mesh Network 13
transforming the design, implementation, and use of deals with the tree construction, while here we are
those devices. Simultaneously, as real-time video interested in finding the maximum per flow bit-rate for
communications become part of our daily lives and our a given instance of the tree.
suite of business tools, we are seeing the beginnings of
persistent conversations across contexts tied more to C. Packet Loss and Delay-Jitter Problem
the user than the devices being used. As we move
through office, car, home, and elsewhere, our devices There are two kinds of packet losses that occur for
will be coordinated and linked to maintaining the real-time video transmission over multi-hop wireless
continuity of our communication events. In other networks. Firstly, a packet might be received corrupted
words, I could start a conference call on my office due to channel errors [6]. 802.11 MAC uses
computer, shift the call to my mobile device for my retransmissions to improve the reliability. Secondly,
commute home, and finish the call on my home for playback of real-time video every packet has a
computer or web-enabled television. deadline before which it has to be received at the
receiver. Packets that arrive late are considered lost
I. PROBLEM & SOLUTION and discarded. Packet losses induce distortion in the
reconstructed video and degrade the quality of the
A. Routing Problem video. Thus it is desirable to reduce losses. Packet
losses and network congestion cause large variations in
Streaming videos have high-bandwidth the one-way delay experienced by packets of a flow.
requirements. The routing problem is to determine Standard technique to smooth out this jitter is to
paths between each video source and the receiver such employ a playback buffer that adds some delay
that all flows get a good throughput while utilizing the between actual streaming and playback time. Packets
available bandwidth effectively. Since all flows end at received ahead in time are buffered before being
the receiver, this problem is same as constructing an played back. Theoretically, jitter can be completely
aggregation tree with receiver as the root and sources eliminated by having an infinite playback buffer. But
as leaves or intermediate nodes of the tree. due to the nature of live streaming, it is desirable to
Total number of bytes that can be received by the have a low delay before viewing. Therefore, the goal is
receiver in a unit time is limited by the capacity of the to employ as little playback delay as possible.
channel. This is the upper bound for the sum of the Moreover, the lower delay also implies lower buffer
throughput of all flows. However, the actual aggregate size requirements. In order for video to be played back
throughput is usually much less than this. The reason without disruption, the playback buffer should never
for this is as follows. Since all nodes are operating in be empty.
the same frequency band, the nodes that are within 1. Simulation setup and scenarios
each other’s sensing range contend for the channel
access. Intra-flow contention occurs when nodes along In order to check the effect of the size of the
a multi-hop path carrying the same set of flows contention window at MAC Layer for real-time video
contend with each other. This limits the total transmission in WMN, I use OPNET Modeler [10] 11.5
throughput along a multi-hop path. In contrast, when as a simulation software package with Microsoft visual
one or more flows merge together or when they are C++ 6.0 as a supporting tool on Microsoft Windows
spatially close enough to contend with each other, the XP operating system. The Opnet simulation software
capacity is shared among the flows and the throughput package is structured so that each network is modelled
of each flow reduces. While it is hard to eliminate as a configuration of nodes which are interconnection
intra-flow contention for a single-channel mesh of specific modules representing the various processes
network, spatial separation of routes for different flows those take place in the actual communications
can reduce inter-flow contention and improve the equipment. In the case of wireless network, the
throughput for each flow. interconnections among the nodes are automatically
determined during the process of the simulation as a
B. Fairness and Rate Allocation Problem function of user-supplied propagation parameters, such
as the effective transmission range of nodes.
Since our system model assumes that the video
sources are identical and generate similar bit-rate Scenario for simulation is shown in fig below. The
streams, the network resources need to be fairly shared size of scenario is office level and contains total 16
among all the flows. This can be achieved by a rate numbers of nodes.
based flow control at each of the sources [7]. All the In Fig.3 we assume that all stations are steady
flows are assigned the same bit-rate that can be except video receiver. Video receiver follows the path
transported successfully to the tree root. The rate which is shown using green line and experiences two
allocation and fairness problem is to determine the handovers at access point. ftp_client and ftp_server are
actual rate that can be supported by the aggregation for generating traffic.
tree. This problem is different from the routing, which
www.ijorcs.org
4. 14 Rajanikanth Aluvalu, NitinBirari, Supriya Byreddy
Video Server node model:
Fig.3 Simulation scenario
2. Node Model Editor
The Node Editor is used to create models of nodes.
The node models are then used to create node
instances within networks in the Project Editor.
Internally, OPNET node models have a modular
structure. You define a node by connecting various
modules with packet streams and statistic wires. The
connections between modules allow packets and status
information to be exchanged between modules. Each
module placed in a node serves a specific purpose, Fig.4 Video server node model
such as generating packets, queuing packets,
processing packets, or transmitting and receiving Tx Manager keeps track to the information for packets
packets. forwarding.
This is an OPNET node model for wireless network Video Receiver node Model:
nodes which incorporates the proposed scheme for
network simulation. Wireless_lan_receiver and
wireless_lan_ transmitter process model of node
model implements the functionality of the Physical
Layer. Wireless_lan_mac and wireless_mac_intf
process model implements functionality of the Link
Layer for 802.11 MAC Protocol. Dsr_routing and
dsr_intf process model implements functionality for
Network Layer using DSR Routing Protocol. Process
models above this process models implements
functionality of Upper Layers.
Here the encoder process uses synthetic video
source based upon the group-of-pictures gamma-beta
auto-regression (GOP GBAR) model. It is used for
variable-rate MPEG video sources.
Network Abstraction Layer (NAL) is a part of
the H.264 Video Coding Standard. The coded video
data is organized into NAL units, each of which is
effectively a packet that contains an integer number of
bytes. The first byte of each NAL unit is a header byte Fig.5 Video receiver node model
that contains an indication of the type of data in the
NAL unit, and the remaining bytes contain payload Decoder process decodes and reforms video packets
data of the type indicated by the header. The NAL unit received.
structure definition specifies a generic format for use Automatic Repeat Request (ARQ) manager process
in both packet-oriented and bit stream-oriented responsible for receive packet and send back
transport systems, and a series of NAL units generated acknowledge to the server back.
by an encoder is referred to as a NAL unit stream [11].
www.ijorcs.org
5. Efficient real-time Video Transmission in Wireless Mesh Network 15
Access point node Model: FTP Client node model:
Fig.8 FTP client node model
3. MAC Layer Process Model Editor
Fig.6 Access point node model To create process models which control the
underlying functionality of the node models created in
Sink process receives the packet store in queue and the Node Editor one can use the Process Editor.
forwards towards the destination based on FIFO. Process models are represented by finite state
machines (FSMs) and are created with icons that
FTP Server node model:
represent states and lines that represent transitions
between states. Operations performed in each state or
for a transition are described in embedded C or C++
code blocks[9].
INIT
Initialization of the process mode. All the
attributes are loaded in this routine.
BSS_INIT
Schedule a self interrupt to wait for MAC
interface to move to next state after registering
IDLE
The purpose of this state is to wait until the packet has
arrived from the higher or lower layer.
In this state following interrupt can occur:
1. Data arrival from application layer
2. Frame (DATA, ACK, RTS, CTS) rcvd from PHY
layer
3. Busy interrupt stating that frame is being rcvd
4. Call interrupt indicating that more than one frame
is received.
When Data arrives from the application layer, insert
it in the queue. If receiver is not busy then set
Deference to DIFS and Change state to "DEFER"
state.Rcvd RTS, CTS, DATA, or ACK (frame rcvd
interrupt) set Backoff flag if the station needs to
Fig.7 FTP server node model backoff[11].
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6. 16 Rajanikanth Aluvalu, NitinBirari, Supriya Byreddy
change the states to wait for Response otherwise just
DEFER for next transmission.
2. If expected frame is rcvd then check what is the next
frame to transmit and set appropriate deference
timer.
a. If all the data fragments are transmitted then check
whether the queue is empty or If not then based on
threshold fragment the packet and based on
threshold decide whether to send RTS or not.
b. If there is a data to be transmitted then wait for
DIFS duration before contending for the channel.
c. If nothing to transmit then go to IDLE and wait for
the packet arrival from higher or lower layer.
3. If expected frame is not rcvd then infer collision, set
Fig.9 MAC Layer process model back off flag, if retry limit is not reached retransmit
If the frame is destined for this station then send the frame by contending for the channel.
appropriate response and set deference to SIFS clear If there is no frames expected then check to see if there
the receiver busy flag and clamp any data is any other frame to transmit. Also mark the channel
transmission. as idle.
If it's a broadcast frame then set deference to NAV BKOFF_NEEDED
and schedule self interrupt and change state to Determining whether to backoff or not. It is needed
"DEFER". Copy the frame (RTS/DATA) in when station preparing to transmit frame discovers
retransmission variable if receiver start receiving that the medium is busy or when the station infers
frame (busy stat interrupt) then set a flag indicating collision.
receiver is busy, if receiver start receiving more than Backoff is not needed when the station is
one frame then set the rcvd frame as invalid frame set responding to the frame.
deference time to EIFS. If backoff needed, then check whether the station
completed its backoff in the last attempt. If not then
DEFER resume the backoff from the same point, otherwise
Call the interrupt processing routine for each interrupt. generate a new random number for the number of
WAIT_FOR_RESPONSE backoff slots.
At the Enter execs level change in code is shown in
The purpose of this state is to wait for the response the fig.10 for changing the size of contention window.
after transmission. The only frames which require
BACKOFF
acknowledgements are RTS and DATA frame. In this
Call the interrupt processing routine for each interrupt.
state following interrupt can occur:
TRANSMIT
1. Data arrival from application layer
2. Frame (DATA, ACK, RTS, CTS) rcvd from PHY If the packet is received while the station is
layer transmitting then mark the received packet as bad.
3. Frame timeout if expected frame is not received The behaviour of the simulation model governed by
4. Busy interrupt stating that frame is being received a number of user defined parameters, lumped under the
5. Collision interrupt stating that more than one frame Wireless LAN Parameters attribute and selected via an
is received OPNET graphical user interface. The parameters are
Queue the packet as Data Arrives from application listed in figures below. Some parameters are of
layer numeric type where as others are popup list type.
If received unexpected frame then collision is inferred
and retry count is incremented if a collision stat 3.4 Parameter values:
interrupt from the receiver then flag the received frame The behaviour of the simulation model governed by
as bad. a number of user defined parameters, lumped under the
FRM_END Wireless LAN Parameters attribute and selected via an
The purpose of this state is to determine the next OPNET graphical user interface. The parameters are
unforced state after completing transmission. listed in figures below. Some parameters are of
There are three cases: numeric type where as others are popup list type.
1. If just transmitted RTS or DATA frame then wait for
response with expected_frame_type variable set and
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7. Efficient real-time Video Transmission in Wireless Mesh Network 17
Fig.10 Code change
Fig.12 Attributes of Video Server
Fig.11 Attributes of Video Receiver
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8. 18 Rajanikanth Aluvalu, NitinBirari, Supriya Byreddy
II. RESULTS AND OUTCOMES B. Throughput Statistic
Results are obtained as object level statistics, Delay
Throughput is calculated based on time taken for
time and Throughput, collected by executing the
successful data delivery. Fig 15 we can find the
simulation model for 40 seconds and compared with
through put achieved for standard MAC and in fig 16
results obtained for standard MAC.
we can find the through put achieved for modified
A. Delay Statistic MAC. We can find improved through put in Modified
MAC.
The delay in real-time MAC layer is exploited by
the broadcast nature of wireless medium and limited
loss tolerance of the applications. Each additional
transmission consumes additional power and increases
network load is time delayed in delivery of data. Here
delay is introduced due to handovers. We can find the
difference in delay statistics for standard and modified
MAC. We can find the reduction of time delay in
modified MAC. The difference is shown in Fig 13 and
Fig 14.
Fig.4.3 Throughput for Standard MAC
Fig.13 Delay Statistics for Standard MAC
Fig.4.4 Throughput for Modified MAC
4.3 Result Analysis
By comparing the results obtained for delay time
for standard MAC and modified MAC, we can see that
delay time is decreased up to 0.1 seconds. By
comparing statistics for throughput using Standard
MAC and modified MAC, we can see that throughput
is increased. Finally we are able to simulate
transmission with less delay time and improved
throughput.
Fig.14 Delay Statistics for Modified MAC
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9. Efficient real-time Video Transmission in Wireless Mesh Network 19
III. CONCLUSION
In this paper we have proposed a Simulation model
to demonstrate higher through put by reducing delay
time during real time video transmission in wireless
mesh networks. When we use WMNS, the complexity
lies in Routing, Hence we have shown emphasis on
routing, which causes more delay time during video
transmission, if we don’t have an efficient mechanism.
We have verified the effect of the size of contention
window at MAC Layer for real time video
transmission in WMN. We have used OPNET Modeler
11.5 as a simulation software package with Microsoft
visual C++ 6.0 as supporting tool on Microsoft
Windows XP operating system. Finally the results are
satisfactory
IV. REFERENCES
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PabloBrenner, www.sss-mag.com/pdf/802_11tut.pdf
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[11] S. Mao, Y. T. Hou, X. Cheng, and H. D. Sherali,
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