Computing has evolved from isolated machines, providing calculative support of applications, toward communication networks that provide functional support to groups of people and embedded systems. Perhaps, one of the most compelling feature and benefit of computers is their overwhelming computing efficiency. Today, we conceive distributed computational systems of an ever-increasing sophistication, which we then apply in various settings – critical support functions of our society just to name one important application area. The spread and impact of computing, in terms of so-called information society technologies, has obviously gained a very high momentum over the years and today it delivers a technology that our societies have come to depend on. To this end, concerns related to our acceptance of qualities of computing, e.g., dependability, are increasingly emphasized by users as well as vendors. An indication of this increased focus on dependability is found in contemporary efforts of mitigating the effects from systemic failures in critical infrastructures, e.g., energy distribution, resource logistics, and financial transactions. As such, the dependable function of these infrastructures is governed by means of more or less autonomic computing systems that interact with cognitive human agents. However, due to intricate system dependencies as well as being situated in our physical environment, even the slightest – unanticipated – perturbation in one of these embedded systems can result in degradations or catastrophic failures of our society. We argue that this contemporary problem of computing mainly is due to our own difficulties in modeling and engineering the involved system complexities in an understandable manner. Consequently, we have to provide support for dependable computing systems by means of new methodologies of systems engineering. From a historical perspective, computing has evolved, from being supportive of quite well defined and understood tasks of algorithmic computations, into a disruptive technology that enables and forces change upon organizations as well as our society at large. In effect, a major challenge of contemporary computing is to understand, predict, and harness the involved systems’ increasing complexity in terms of constituents, dependencies, and interactions – turning them into dependable systems. In this thesis, we therefore introduce a model of open computational systems, as the means to convey these systems’ factual behavior in realistic situations, but also in order to facilitate our own understanding of how to monitor and control their complex interdependencies. Moreover, since the critical variables that govern these complex systems’ qualitative behavior can be of a very elusive nature, we also introduce a method of online engineering, whereby cognitive agents – human and software – can instrument these open computational systems according to their own subjective and temporal understanding of some complex situation at hand.

Presented at 2014 Arizona Library Association Annual Conference, Scottsdale, AZ / Open educational resources (OER) are teaching and learning materials that are free to use, customize, and share. There’s a goldmine of OER online, but locating them is like trying to herd cattle (or cats). It takes persistence and a knack for tracking down things that are scattered all over. OER range from digital textbooks, lesson plans, and games to assignments, videos, and lab notes. Learn about the benefits of OER, potential barriers, where to find high-quality OER, and how to increase customers’ awareness of them. The target audience for this presentation is anyone who works with K-12 classes, college students, instructors, and lifelong learners.

published_or_final_version / Urban Design / Master / Master of Urban Design

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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.