Reliable Failure Restoration with Bayesian Congestion Aware for Software Defined Networks

SoftwareDefined Networks(SDN)introduced better network management by decoupling control and data plane.However,communication reliability is the desired property in computer networks.The frequency of communication link failure degrades network performance,and service disruptions are likely to occur.Emerging network applications,such as delaysensitive applications,suffer packet loss with higher Round Trip Time(RTT).Several failure recovery schemes have been proposed to address link failure recovery issues in SDN.However,these schemes have various weaknesses,which may not always guarantee service availability.Communication paths differ in their roles;some paths are critical because of the higher frequency usage.Other paths frequently share links between primary and backup.Rerouting the affected flows after failure occurrences without investigating the path roles can lead to post-recovery congestion with packet loss and system throughput.Therefore,there is a lack of studies to incorporate path criticality and residual path capacity to reroute the affected flows in case of link failure.This paper proposed Reliable Failure Restoration with Congestion Aware for SDN to select the reliable backup path that decreases packet loss and RTT,increasing network throughput while minimizing post-recovery congestion.The affected flows are redirected through a path with minimal risk of failure,while Bayesian probability is used to predict post-recovery congestion.Both the former and latter path with a minimal score is chosen.The simulation results improved throughput by(45%),reduced packet losses(87%),and lowered RTT(89%)compared to benchmarking works.

RESEARCH ON THE PACKING ALGORITHM FOR ANTI-SEU OF FPGA BASED ON TRIPLE MODULAR REDUNDANCY AND THE NUMBERS OF FAN-OUTS OF THE NET

Static Random Access Memory(SRAM) based Field Programmable Gate Array(FPGA) is widely applied in the field of aerospace, whose anti-SEU(Single Event Upset) capability becomes more and more important. To improve anti-FPGA SEU capability, the registers of the circuit netlist are tripled and divided into three categories in this study. By the packing algorithm, the registers of triple modular redundancy are loaded into different configurable logic block. At the same time, the packing algorithm considers the effect of large fan-out nets. The experimental results show that the algorithm successfully realize the packing of the register of Triple Modular Redundancy(TMR). Comparing with Timing Versatile PACKing(TVPACK), the algorithm in this study is able to obtain a 11% reduction of the number of the nets in critical path, and a 12% reduction of the time delay in critical path on average when TMR is not considered. Especially, some critical path delay of circuit can be improved about 33%.

PERT and CPM in Project Management with Practical Examples

This paper reviewed the concepts of Project Evaluation Review Technique and Critical Path Method in project management with practical examples. The methods and success of quantitative decision-making approaches in project management through the use of project evaluation review technique and the critical path method as regards project duration and critical activities of a project, were discussed. The review found that while both methods are effective in achieving success in project management, the relationship and connectivity of activities involved in a project life cycle are key aspects. The paper concludes that the project evaluation review technique is more effective when the duration of the project is uncertain, while the critical path method is effective when the project’s end time is certain. The paper, therefore, recommends that to achieve maximum operative efficiency in utilizing resources in project management, prior to commencing the execution of a project, all required resources to cover every activity must be assembled and prioritized to eliminate interruptions that could bring delay and unnecessary cost implications. Again, policies focused on improving project execution should be implemented in developing nations to minimize the many cases of failed and delayed projects. Subsequently, stakeholders in projects must be given the right, under the law, to prosecute the government, its agencies and/or the executors of projects for failure to execute a project on schedule.