The coverage and energy issues are the fundamental problems which prevent the development of wireless sensor networks. In order to accurately evaluate the monitoring quality (coverage), one needs to model the interactive of sensors, phenomenons and the environment. Furthermore, in collaborative with scheduling algorithm and computer optimization, protocols can improve the overall monitoring quality and prolong the lifetime of network. This thesis is an investigation of coverage problem and its relative applications in the wireless sensor networks. We first discuss the realistic of current boolean sensing model and propose an irregular sensing model used to determine the coverage in the area with obstacles. We then investigate a joint problem of maintaining the monitoring quality and extending the lifetime of network by using scheduling schemes. Since the scheduling problem is NP hard, genetic algorithm and Markov decision process are used to determine an achievable optimal result for the joint problem of coverage-preserving and lifetime-prolong. In order to avoid the cost of centralized or distributed scheduling algorithms, a localized coverage-preserving scheduling algorithm is proposed by exploring the construction process of Voronoi diagram. Besides exploring the coverage characteristic in a static wireless sensor network, we investigate the coverage problem when the mobile elements are introduced into network. We consider the single-hop mobile data gathering problem with the energy efficiency and data freshness concerns in a wireless sensor network where the connectivity cannot be maintained. We first investigate the upper/lower bound of the covering time for a single collector to cover the monitoring area. Through our investigation we show that for a bounded rectangle area a hexagon walk could explore the area more efficiently than a random walk when the edges of area are known. We then propose a virtual force mobile model (VFM) in which the energy consumption for data transmission is modeled as a virtual elastic force and used to guide of mobile collectors to move to optimal positions for energy saving.

No description available.

Approved for public release; distribution is unlimited / Surgical technicians at Naval hospitals provide a host of services related to surgical procedures that include handing instruments to surgeons, assisting operating room nurses, prepping and cleaning operating rooms, and administrative duties. At the Naval Medical Center San Diego (NMCSD), there are 83 surgical technicians that must be scheduled for these duties. The three military and one civilian hospital interviewed for this thesis manually schedule these duties. Weaknesses of these manual schedules exposed during interviews at these hospitals include assignment inequities and the time needed to create them. This thesis reports on an optimization based and spreadsheet implemented tool developed to schedule surgical technicians for both daily and weekly duties at a Naval hospital. We demonstrate the tool for the surgical technician department at NMCSD. The schedulers at NMCSD verify the utility of the developed tool and cite a drastic reduction in the time required to generate timely, equitable, and accurate schedules. The study also investigates historical operating room usage data and makes suggestions for improving scheduling practices based on these data. / Commander (Select), United States Navy

In this dissertation, we discuss throughput-optimal scheduling design in multiuser wireless networks. Throughput-optimal scheduling algorithm design in wireless systems with flow-level dynamics is a challenging open problem, especially considering that the majority of the Internet traffic are short-lived TCP controlled flows. In future wireless networks supporting machine-to-machine and human-to-human applications, both short-lived dynamic flows and long-lived persistent flows coexist. How to design the throughput-optimal scheduling algorithm to support dynamic and persistent flows simultaneously is a difficult and important unsolved problem. Our work starts from how to schedule short-lived dynamic flows in wireless systems to achieve throughput-optimality with queue stability. Classic throughput-optimal scheduling algorithms such as the Queue-length based Maxweight scheduling algorithm (QMW) cannot stabilize systems with dynamic flows in practical communication networks. We propose the Head-of-Line (HOL) access delay based scheduling algorithm (HAD) for flow-level dynamic systems, and show that HAD is able to obtain throughput-optimality which is validated by simulation. As the Transmission Control Protocol (TCP) is the dominant flow and congestion control protocol for the Internet nowadays, we turn our attention to the compatibility between throughput-optimal schedulers and TCP. Most of the existing throughput-optimal scheduling algorithms have encountered unfairness problem in supporting TCP-controlled flows, which leads to undesirable network performance. Motivated by this, we first reveal the reason of the unfairness problem, then study the compatibility between HAD and TCP with different channel assumptions, and finally analyze the mean throughput performance of HAD. The result shows that HAD is compatible with TCP. Since the assumption of an infinite buffer size in the existing theoretical analysis of throughput-optimality is not practical, we analyze the queueing behaviour of the proposed throughput-optimal scheduling algorithm to provide useful guidelines for real system design by using the Markov chain analytic model. We propose the analytic model for the queuing and delay performance for the HAD scheduler, and then further develop an approximation approach to reduce the complexity of the model. Finally, we propose a throughput-optimal scheduling algorithm for hybrid wireless systems with the coexistence of persistent and dynamic flows. Then, to generalize the throughput-optimal scheduling, the control function in the scheduling rule is extended from a specific one to a class of functions, so that the scheduling design can be more flexible to make a tradeoff between delay, fairness, etc. We show that the hybrid wireless networks with coexisting persistent flows and dynamic flows can be stabilized by our proposed scheduling algorithm which can obtain throughput-optimality. In summary, we solve the challenging problem of designing throughput-optimal scheduling algorithm in wireless systems with flow-level dynamics. Then we show that our algorithm can support TCP regulated flows much better than the existing throughput-optimal schedulers. We further analyze the queueing behaviour of the proposed algorithm without the assumption of infinite buffer size that is often used in the throughput-optimality analysis in the literature, and the result provides a guideline for the implementation of our algorithm. At last, we generalize the proposed scheduling algorithm to support different types of flows simultaneously in practical wireless networks. / Graduate / chenyi.nwpu@gmail.com

Network virtualization has become an important aspect of the Telecom industry. The need forefficient, scalable and reliable virtualized network functions is paramount to modern networking.Open vSwitch is such virtual switch that attempts to extend the usage of virtual switches to industrygrade performance levels on heterogeneous platforms.The aim of the thesis is to give an insight into the working of Open vSwitch. To evaluate theperformance of Open vSwitch in various virtualization scenarios such as KVM (second companionthesis)[1] and Docker. To investigate different scheduling techniques offered by the Open vSwitchsoftware and supported by the Linux kernel such as FIFO, SFQ, CODEL, FQCODEL, HTB andHFSC. To differentiate the performance of Open vSwitch in these scenarios and scheduling capacitiesand determine the best scenario for optimum performance.The methodology of the thesis involved a physical model of the system used for real-timeexperimentation as well as quantitative analysis. Quantitative analysis of obtained results paved theway for unbiased conclusions. Experimental analysis was required to measure metrics such asthroughput, latency and jitter in order to grade the performance of Open vSwitch in the particularvirtualization scenario.The results of the thesis must be considered in context with a second companion thesis[1]. Both thethesis aim at measuring the performance of Open v-Switch but the virtualization scenarios (Dockerand KVM) which are chosen are different, However, this thesis outline the performance of Open vSwitch and linux bridge in docker scenario. Various scheduling techniques were measured fornetwork performance metrics across both Docker and KVM (second companion thesis) and it wasobserved that Docker performed better in terms of throughput, latency and jitter. In Docker scenarioamongst the scheduling algorithms measured, it has almost same throughput in all schedulingalgorithms and latency shows slight variation and FIFO has least latency, as it is a simplest algorithmand consists of default qdisk. Finally jitter also shows variation on all scheduling algorithms.The conclusion of the thesis is that the virtualization layer on which Open vSwitch operates is one ofthe main factors in determining the switching performance. The KVM scenario and Docker scenarioeach have different virtualization techniques that incur different overheads that in turn lead to differentmeasurements. This difference occurs in different packet scheduling techniques. Docker performsbetter than KVM for both bridges. In the Docker scenario Linux bridge performs better than that ofOpen vSwitch, throughput is almost constant and FIFO has a least latency amongst all schedulingalgorithms and jitter shows more variation in all scheduling algorithms.

Network virtualization has become an important aspect of the Telecom industry. The need for efficient, scalable and reliable virtualized network functions is paramount to modern networking. Open vSwitch is a virtual switch that attempts to extend the usage of virtual switches to industry grade performance levels on heterogeneous platforms.The aim of the thesis is to give an insight into the working of Open vSwitch. To evaluate the performance of Open vSwitch in various virtualization scenarios such as KVM and Docker (from second companion thesis)[1]. To investigate different scheduling techniques offered by the Open vSwitch software and supported by the Linux kernel such as FIFO, SFQ, CODEL, FQCODEL, HTB and HFSC. To differentiate the performance of Open vSwitch in these scenarios and scheduling capacities and determine the best scenario for optimum performance.The methodology of the thesis involved a physical model of the system used for real-time experimentation as well as quantitative analysis. Quantitative analysis of obtained results paved the way for unbiased conclusions. Experimental analysis was required to measure metrics such as throughput, latency and jitter in order to grade the performance of Open vSwitch in the particular virtualization scenario.The result of this thesis must be considered in context with a second companion thesis[1]. Both the theses aim at measuring and modeling performance of Open vSwitch in NFV. However, the results of this thesis outline the performance of Open vSwitch and Linux bridge in KVM virtualization scenario. Various scheduling techniques were measured for network performance metrics and it was observed that Docker performed better in terms of throughput, latency and jitter. In the KVM scenario, from the throughput test it was observed that all algorithms perform similarly in terms of throughput, for both Open vSwitch and Linux bridges. In the round trip latency tests, it was seen that FIFO has the least round trip latency, CODEL and FQCODEL had the highest latencies. HTB and HFSC perform similarly in the latency test. In the jitter tests, it was seen that HTB and HFSC had highest average jitter measurements in UDP Stream test. CODEL and FQCODEL had the least jitter results for both Open vSwitch and Linux bridges.The conclusion of the thesis is that the virtualization layer on which Open vSwitch operates is one of the main factors in determining the switching performance. Docker performs better than KVM for both bridges. In the KVM scenario, irrespective of the scheduling algorithm considered, Open vSwitch performed better than Linux bridge. HTB had highest throughput and FIFO had least round trip latency. CODEL and FQCODEL are efficient scheduling algorithms with low jitter measurements.

This thesis describes investigations into the phenomenon of time estimation in mechanical engineering design. Time estimating in this context refers to estimating in advance the approximate duration of a new design project, for the purpose of preparing schedules. The thesis describes background to the estimation problem, including practical and theoretical aspects of design, design management and market conditions. The research presented is based on data gathered from industrial collaborators, therefore detailed descriptions of the collaborating firms are included. A quantitative study is described which demonstrates that current estimation techniques are not infallible; and that there can be a statistically significant link between the estimated and actual completion times. A process of grounded theorising, based on expert interviews, is presented. Models of the design estimation task were generated by this process, and are included. Differences were found in the models for the estimation of times in an Engineer to Order (ETO) environment, and estimation in a Volume Manufacturing environment. The models were corroborated firstly by checking if they could be recognised and endorsed by the experts from which they were generated, and. secondly by checking if they could be recognised and endorsed by an expert not involved in the original model generation. Correspondence was found to be good. A modified model of time estimation is presented, taking into account the findings of the corroboration exercise. Finally, an example of a simple tool for assisting the estimation process is included.

A research project submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science. / The problem of scheduling with sequence-dependent set-up times in a dynamic environment is investigated by studying how various dispatching rules perform when used to schedule two cranes. Motivated by a practical scheduling problem, the effect on production by delays due to the conflicts that result between cranes is examined. The problem is formalized, and it is shown that it can be classified as a problem of scheduling with both sequence-dependent set-up and processing times. The effectiveness of simple dispatching procedures that are used in machine scheduling and for the control of automated guided vehicles is studied, using a simulation of a crane aisle with jobs arriving dynamically. In addition, a dispatching rule, which explicitly uses information regarding the state of the second crane, is examined. The simulation results confirm the non-dominance of certain dispatching procedures, and show how performance is improved as the rules are provided more information regarding the state of the scheduling environment. It is shown that when there are sequence-dependent processing times, a scheduling heuristic that uses global information does significantly better than more commonly used local heuristics. / AC2017

Building Information Modeling“BIM" is becoming a better known established collaboration process in the construction industry. Owners are increasingly requiring BIM services from construction managers, architects and engineering firms. Many construction firms are now investing in“BIM" technologies during bidding, preconstruction, construction and post construction. The goal of this project is to understand the uses and benefits of BIM for construction managers and examine BIM based scheduling. There are two objectives to this project. First is to identify the current uses of BIM in the Architectural / Engineering / Construction / Facility Management industry to better understand how the BIM-based“build to design" and“design to build" concepts can be used by construction managers under the Construction Management at Risk project delivery system. Second, a focus is placed on analyzing 3D and 4D BIM as well as BIM based scheduling. The research was conducted through literature review, case studies, and interviews. First, the research identified the uses of Building Information Modeling for preconstruction, construction and post construction phases. Then, the project examined the uses and benefits of BIM in the construction of a research facility. Subsequently, a prototype 4D Building Information Model was created and studied. Furthermore, the BIM-based schedule was integrated to the 4D model. Finally, the project concluded with an analysis on the use, advantages and setbacks of BIM and its tools.

Chan Tak Chun, Andrew. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references. / Abstract --- p.ii / Acknowledgements --- p.iv / Table of Contents --- p.v / Lists of Tables and figures --- p.vi / Chapter Chapter1 --- Introduction and Literature Review --- p.1 / Chapter Chapter2 --- Problem Formulation --- p.15 / Chapter Chapter3 --- Solution Method --- p.20 / Chapter Chapter4 --- Application to Air Cargo Company --- p.31 / Chapter Chapter5 --- Implementation --- p.45 / Chapter Chapter6 --- Conclusion --- p.53 / References --- p.R-l / Appendix A --- p.A-l / Appendix B --- p.B-l / Appendix C --- p.C-l