Modeling and simulation: the paradigm shift for cohesive resource harnessing

This paper presents the details of a specialized framework developed for the teaching of the modeling and simulation course for postgraduate students in Universiti Putra Malaysia. The unique feature of the subject is that it requires students ability to gain knowledge in several fields and relate them aptly to the need of performance analysis. IT also demands acquiring skills to develop comprehensive tools using the principles of discrete event simulation. The developed framework focuses on student-centered learning of queuing analysis, the development of models and relating them to performance analysis, the specialized activities to derive discrete event simulation components, and output analysis. It also deals with the tool's impact on research within the area. The framework was evaluated in a course. It showed the ability to enhance the level of student's understanding and application of competency gained to research

Dynamic layout algorithms for wireless field hockey strategy system

Sensor deployment in the field of sports is providing enormous potential for elevating the playing field standards. This paper presents an enhanced localization algorithm which harnesses the dynamic and reconfiguration attributes of field hockey players on a strategy board; known as the Wireless Field Hockey Strategy System (WiHoc Ver1.0). The proposed algorithm utilized for determining the location of field hockey players overcomes the constraints and confined anchor based WiHoc Ver 1.0. The resolution encompasses the new versatile platform which captures the positional location within the parameters of a hockey pitch and of cooperative nodes to determine the optimal location of anchor positioning to ensure that the achieved accuracy of localization is enhanced. The proposed algorithm was evaluated extensively through discrete - event simulations. The acquired results via the accuracy performance metrics validated the enhanced ability of the proposed algorithm

New algorithms to minimize handoff latency in AMTree protocol

In active networks, programs can be injected to network elements (routers/switches). This allows programmers to enhance existing protocols or deploy new protocols. AMTree protocol is an active network based protocol that makes sending packets to receivers, after source migration, an efficient process. In AMTree protocol, after source migration, handoff latency computed from the time of reconnecting to a new base station until finding nearest core to the mobile source. In this paper the authors present two new algorithms to minimize the handoff latency in AMTree protocol. They show that handoff latency is much lower than that of AMTree handoff algorithm if the mobile source connects to a base station which is subscribed to the multicast group

A discrete event simulation for utility accrual scheduling in uniprocessor environment

This research has focused on the proposed and the development of an event based discrete event simulator for the existing General Utility Scheduling (GUS) to facilitate the reuse of the algorithm under a common simulation environment. GUS is one of the existing TUF/UA scheduling algorithms that consider the Time/Utility Function (TUF) of the executed tasks in its scheduling decision in a uniprocessor environment. The scheduling optimality criteria are based on maximizing accrued utility accumulated from execution of all tasks in the system. These criteria are named as Utility Accrual (UA). The TUF/ UA scheduling algorithms are design for adaptive real time system environment. The developed GUS simulator has derived the set of parameter, events, performance metrics and other unique TUF/UA scheduling element according to a detailed analysis of the base model

Performance evaluation of the geographic routing protocols scalability

Scalability is an important design factor for evaluating the performance of routing protocols as the network size or traffic load increases. One of the most appropriate design methods is to use geographic routing approach to ensure scalability. This paper describes a scalability study comparing Secure Region Based Geographic Routing (SRBGR) and Dynamic Window Secure Implicit Geographic Forwarding (DWSIGF) protocols in various network density scenarios based on an end-to-end delay performance metric. The simulation studies were conducted in MATLAB 2106b where the network densities were varied according to the network topology size with increasing traffic rates. The results showed that DWSIGF has a lower end-to-end delay as compared to SRBGR for both sparse (15.4%) and high density (63.3%) network scenarios. Despite SRBGR having good security features, there is a need to improve the performance of its end-to-end delay to fulfil the application requirements

Co-channel interference mitigation techniques in multi-cell OFDMA Relay-Based Cellular Networks: a survey

Orthogonal Frequency Division Multiplexing Access (OFDMA) technology along with cooperative relay networks are generally described as an appropriate applicant for developed cellular networks because of the improvements to system performance through flexible resource allocation schemes. In these networks interference-aware resource allocation or interference coordination, represents an important role in raising resource utilization as well as enhancing cell throughput. This paper focuses on existing co-channel interference mitigation methods in multi-cell OFDMA Relay Based Cellular Networks (RBCNs). It aims to utilize the advantages of relay stations while reducing the negative effects of introduced interference. This research first presents the general system model scenarios of interference in RBCNs and provides an overview of the problem. It then compares the potential interference scenarios in these systems. Our study examines the techniques based on the frequency reuse factor they use and shows that even by maintaining the frequency reuse at one; we can maximize the system throughput

Pro-active QoS resource management schemes for future integrated packet-switched networks

In this research two pro-active dynamic QoS resource management schemes are designed, namely the dynamic QoS control scheme with delay estimation, and the hybrid dynamic QoS control scheme. In both schemes, every new packet arrival is compared against the computed estimated delay it will experience, prior to being admitted into the buffer. If the computed estimated delay expires the requested delay bound, then the packet is dropped. In the hybrid scheme, every packet is first assessed for the estimated delay prior to being admitted into the buffer, subsequently the packets which have been successfully admitted into the buffer are evaluated on the actual delay experienced before being transmitted to the receiver. The paper studies the performance of the two proposed schemes with a dynamic resource management scheme, known as the OCcuPancy_Adjusting (OCP_A). The results obtained through the simulation models show that the proposed schemes have significantly improved the average delay for different traffic patterns. In addition to improving the average delay in delay sensitive traffic, improvement is seen in the average packet loss ratio, and subsequently increasing the throughput of delay sensitive traffic

A new load balancing scheduling model in data grid application

Scheduling an application in data grid is significantly complex and very challenging because of its heterogeneous in nature of the grid system. Thus, Divisible Load Theory (DLT) is a powerful model for modeling data intensive grid problem where both communication and computation load is partitionable. Previously, Task Data Present (TDP) model was proposed based on DLT model. This paper presents an Adaptive TDP (ATDP) model to reduce the makespan. New equations for calculating the load allocation are derived. Experimental results showed that the proposed model can balance the load efficiently

A discrete event modeling and simulation of wave division multiplexing unidirectional slotted ring metropolitan area network

Problem statement: The lack of uniformity in the choice of simulation platforms for optical WDM networks stands behind the difficulty of developing a common simulation environment. Correlating WDM unidirectional slotted ring network to Discrete Event Simulation (DES) encompassing event definition, time advancing mechanism and scheduler has yet to be developed. Approach: The study focused on the proposed and the development of an event based discrete simulator for the WDM unidirectional slotted ring network to facilitate the reuse of the protocol modules under a common simulation environment. The proposed network architecture implemented for the developed simulator employs a separate wavelength as the control information channel. This control information enabled the nodes to monitor their access to the transmission media. Each node was equipped with a tunable transmitter and fixed receiver for data communication. Access nodes were equipped with a fixed transmitter and fixed receiver for the control information exchange. The developed simulator had derived the use of dividing the wavelength into slots. Nodes used these slots to transmit fixed size packets. Slots can be reused by the access node after receiving packets by the deployment of the spatial reuse scheme, thus enhancing the bandwidth utilization. The developed simulator had derived the set of the parameters, events, performance metrics and other unique WDM simulator elements according to a detailed analysis of the base model. Results: The network delay and packet loss were investigated and compared to a benchmark of the modeled domain. Successful deployment of the developed simulator was proven by the generated results. Conclusion: Extensive performance analysis of WDM unidirectional slotted ring network can be deployed using the developed simulator with low computational overheads. Further enhancements were to extend the developed simulator for bidirectional slotted ring supporting fairness control and considering both uniform and non-uniform traffic

Enhanced dynamic bandwidth allocation proportional to queue length with threshold value for VBR traffic

In Asynchronous Transfer Mode (ATM) network, Variable Bit Rate (VBR) service category has been defined to support any application for which the end-system can benefit from statistical multiplexing, by sending information at a variable rate, and can tolerate or recover from a potentially small random loss ratio. Due to its burst characteristic, bandwidth allocation strategy is necessary in order to share the network resources with other traffics fairly. The implementation of proposed approaches; heuristic, Unused Buffer Reallocation (UnBR) and Higher-priority Queue Sharing (HQS), in bandwidth strategy perform better improvement if compare to the proposed strategy. In addition, we observed that a bandwidth strategy did not always perform well, hence, suitable strategies should be chosen depending on the different conditions in order to fulfill its network demand