QUIC is a new secure multiplexed transport protocol built on top of UDP. This general-purpose transport protocol aims to provide the lowest connection latency possible and solve the shortcomings of TCP, UDP, and current problems of the internet. Furthermore, it allows further development of the transport protocol without upgrading the network infrastructure. Last year in May 2021, QUIC was finally standardized by the IETF, allowing for full development and release while also opening the path for future research as older research dated due to using the older version and the finalization of QUIC standard protocol. While there are a lot of different QUIC implementations, this thesis selected two and conducted a performance evaluation on the cloud environment and compared the two while also taking the sustainability aspect into account. Asa result, we will find which of the selected implementation is environmentally friendly through this experiment while also providing good performance. / <p>2022 GENIAL Summer School</p>

This paper presents a Call Admission Control (CAC) algorithm based fuzzy logic to maintain the quality of service using cell breathing concept. When a new call is accepted by a cell, its current user is generally affected due to cell breathing. The proposed CAC algorithm accepts a new call only if the current users in the cell are not jeopardized. Performance evaluation is done for single-cell and multicell scenarios. In multicell scenario dynamic assignment of users to the neighboring cell, so called handoff, has been considered to achieve a lower blocking probability. Handoff and new call requests are assumed with handoff being given preference using a reserved channel scheme. CAC for different types of services are shown which depend upon the bandwidth requirement for voice, data and video. Distance, arrival rate, bandwidth and nonorthogonality factor of the signal are considered for making the call acceptance decision. The paper demonstrates that fuzzy logic with the cell breathing concept can be used to develop a CAC algorithm to achieve a better performance evaluation.

Quality of Service (QoS) routing considered as one of the major components of the QoS framework in communication networks. The concept of QoS routing has emerged from the fact that routers direct traffic from source to destination, depending on data types, network constraints and requirements to achieve network performance efficiency. It has been introduced to administer, monitor and improve the performance of computer networks. Many QoS routing algorithms are used to maximize network performance by balancing traffic distributed over multiple paths. Its major components include bandwidth, delay, jitter, cost, and loss probability in order to measure the end users¿ requirements, optimize network resource usage and balance traffic load. The majority of existing QoS algorithms require the maintenance of the global network state information and use it to make routing decisions. The global QoS network state needs to be exchanged periodically among routers since the efficiency of a routing algorithm depends on the accuracy of link-state information. However, most of QoS routing algorithms suffer from scalability problems, because of the high communication overhead and the high computation effort associated with marinating and distributing the global state information to each node in the network.The goal of this thesis is to contribute to enhancing the scalability of QoS routing algorithms. Motivated by this, the thesis is focused on localized QoS routing that is proposed to achieve QoS guarantees and overcome the problems of using global network state information such as high communication overhead caused by frequent state information updates, inaccuracy of link-state information for large QoS state update intervals and the route oscillating due to the view of state information. Using such an approach, the source node makes its own routing decisions based on the information that is local to each node in the path. Localized QoS routing does not need the global network state to be exchanged among network nodes because it infers the network state and avoids all the problems associated with it, like high communication and processing overheads and oscillating behaviour. In localized QoS routing each source node is required to first determine a set of candidate paths to each possible destination. In this thesis we have developed localized QoS routing algorithms that select a path based on its quality to satisfy the connection requirements. In the first part of the thesis a localized routing algorithm has been developed that relies on the average residual bandwidth that each path can support to make routing decisions. In the second part of the thesis, we have developed a localized delay-based QoS routing (DBR) algorithm which relies on a delay constraint that each path satisfies to make routing decisions. We also modify credit-based routing (CBR) so that this uses delay instead of bandwidth. Finally, we have developed a localized QoS routing algorithm for routing in two levels of a hierarchal network and this relies on residual bandwidth to make routing decisions in a hierarchical network like the internet. We have compared the performance of the proposed localized routing algorithms with other localized and global QoS routing algorithms under different ranges of workloads, system parameters and network topologies. Simulation results have indicated that the proposed algorithms indeed outperform algorithms that use the basics of schemes that currently operate on the internet, even for a small update interval of link state. The proposed algorithms have also reduced the routing overhead significantly and utilize network resources efficiently.

The Quality of Service (QoS) is a profound concept which is gaining increasing attention in the Internet industry. Best-effort applications are now no longer acceptable in certain situations needing high bandwidth provisioning, low loss and streaming of multimedia applications. New emerging multimedia applications are requiring new levels of quality of services beyond those supported by best-effort networks. Quality of service routing is an essential part in any QoS architecture in communication networks. QoS routing aims to select a path among the many possible choices that has sufficient resources to accommodate the QoS requirements. QoS routing can significantly improve the network performance due to its awareness of the network QoS state. Most QoS routing algorithms require maintenance of the global network¿s state information to make routing decisions. Global state information needs to be periodically exchanged among routers since the efficiency of a routing algorithm depends on link-state information accuracy. However, most QoS routing algorithms suffer from scalability due to the high communication overhead and the high computation effort associated with maintaining accurate link state information and distributing global state information to each node in the network. The ultimate goal of this thesis is to contribute towards enhancing the scalability of QoS routing algorithms. Towards this goal, the thesis is focused on Localised QoS routing algorithms proposed to overcome the problems of using global network state information. Using such an approach, the source node makes routing decisions based on the local state information for each node in the path. Localised QoS routing algorithms avoid the problems associated in the global network state, like high communication and processing overheads. In Localised QoS routing algorithms each source node maintains a predetermined set of candidate paths for each destination and avoids the problems associated with the maintenance of a global network state by using locally collected flow statistics and flow blocking probabilities. / Libya's higher education

The McMaster incident detection algorithm is being tested on-line within the Burlington freeway traffic management system (FTMS) as an alternative to the existing California-type algorithm currently in place. This paper represents the most recent and comprehensive evaluation of the McMaster algorithm's performance to date. In the past, the algorithm has been tested using single lane detectors for the northbound lanes only. This evaluation uses data from lanes 1 and 2 for each of the 13 northbound and 13 southbound detector stations. The data was collected during a 60-day period beginning on November 15, 1990 and ending January 13, 1991. Detection rate, mean time-lag to detection and false alarm rate are used to evaluate the performance of the algorithm. As well, those factors such as winter precipitation, which influenced the performance of the algorithm are also examined. To improve the algorithm's detection rate and lower its false alarm rate, it is reccomended that the persistence check used to declare an incident be increased by 30-seconds from 2 to 3 periods. / Thesis / Candidate in Philosophy

<p dir="ltr">Practically, Byzantine faults are not assumed in cloud applications. Byzantine fault-tolerance adds significant cryptographic, communication, throughput, and latency overheads to applications, contributing to the resistance towards its widespread adoption. Existing Byzantine-fault tolerant protocols focus on optimal latency or optimal communication while ignoring the throughput and cryptographic overheads.</p><p dir="ltr">In this thesis, we explore pipelining for Byzantine fault-tolerant applications. Pipelining tasks is a common optimization in distributed systems that involves executing tasks in stages. The idea is that instead of executing a task in an iteration as an atomic unit, we split the execution into stages and execute all stages of <i>different</i> tasks per iteration. We observe significant performance benefits if executing later stages of a task helps other tasks in earlier stages, saving effort in each stage. The length of the pipeline, i.e., the number of stages, determines the latency of an individual task. However, if the pipeline improves the execution of every stage enough, then the latency improves.</p><p dir="ltr">We primarily explore three Byzantine Fault Tolerant (BFT) applications with pipelining: (i) unique chain-based State Machine Replication protocols: <i>Apollo</i>, <i>Artemis</i>, <i>Leto</i>, and <i>Zeus</i>, and (ii) energy-efficient State Machine Replication: <i>EESMR</i>. (iii) random beacon protocols: <i>GRandPiper</i>, <i>BRandPiper</i>, and <i>OptRand</i>. We design them with a pipeline-first approach to improve the throughput, cryptographic, and communication costs at every stage of the pipeline. With respect to latency, we show (i) pipelined SMR protocols where our pipeline stages have constant cryptographic and linear communication costs allowing our protocols to outperform state-of-the-art BFT-SMR protocols in throughput. (ii) pipelined SMR protocols with techniques to make each stage of the pipeline independent, thus achieving demonstrable energy efficiency while allowing an unbounded number of non-interactive parallel proposals. (iii) reduced latencies for reconfiguration-friendly random beacons by using two pipelines: an SMR pipeline to commit and a beacon pipeline to produce random numbers and decoupling the two pipelines thereby removing the impact of the high-latency SMR pipeline on the latency of the randomness output by the system. </p>

Thesis (MBA.) -- University of Limpopo, 2022 / The purpose of this study was to investigate the effects of training and development on employee performance at Mamelodi Clinics, Gauteng Province. This study was guided by the following objectives. To determine the perceived effect of training and development courses on skills development of professional nurses in the Mamelodi clinics, Gauteng Province. To explore the perceived effect of training and development courses on the performance of professional nurses in the Mamelodi clinics, Gauteng Province. To examine which of the attended short courses are more effective in improving the skills of professional nurses. To find out which short courses, according to the professional nurses in the study, were found to be ineffective and unnecessary. The study was of importance to future researchers and academicians as it added new insight into the existing information with regards to employee training and development. It also provided the department of health, both nationally and provincially with an understanding of successes and challenges inherent to training and development and their corresponding effect on employee performance. As a result, this had a contribution towards how training and development are carried out within the organisation. A qualitative research design was deployed in this study to allow investigation of the possible relationship between training and development as well as to establish a comparison between the two. The study population was 45 staff of Mamelodi Clinics which were approved for this study. The data was collected through a questionnaire. Percentages, means, cross-tabulation were used as means of data analysis. The findings were presented using tables and figures. In terms of training and development, the study was able to show that all Mamelodi Clinics under department of health Gauteng Province, has a range of training programmes for different staff of their clinics, and are of high quality standard and very effective. As a result, employee skills, overall performance of staff, and general competence of the employee has sharply increased due to training and development v methods and strategies put in place by department of health, both provincially and nationally. The study showed that in terms of employee performance and motivation, training and development programmes help in increasing employee motivation and thus performance. Employees are thus able to successfully be aligned with the goals, aims and missions of the clinics and the department of health, as well as the Batho Pele principles. The study concludes that training and development have positive effects on employees. The study was able to find that within the clinics, employees are given adequate chance to engage in training and development courses. The study concludes further that more training and development programmes should be undertaken. The study recommends that there should be regularly assessments on employees and their subsequent need for further training and development courses in order to increase employee satisfaction and performance.

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Remote desktop solutions have widespread adoption across the world, allowing people to connect to a computer remotely from anywhere in the world. One widely used solution is TigerVNC which uses the RFB protocol for communication between a client and server. TigerVNC supports several encoding types, which use different techniques to compress image data. Currently, there is a lack of a performance evaluation frameworks for VNC software that makes it possible to measure the performance of not only different encoders, but also the performance of the system that chooses which encoding to use for different parts of the image. This thesis presents a framework that was developed to evaluate the performance of TigerVNC server in real-world scenarios. The framework includes a tool that records an X session losslessly and a benchmarking suite that processes a recorded session, providing data regarding execution time and compression ratio. Benchmarks were run using several encoding settings with different recorded sessions representing real-world scenarios. Results show that TigerVNC server has a good tradeoff between compression ratio and execution time. The work done in this thesis lays a foundation on which future research can be done, leading to improvements in the TigerVNC project.