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Software Defined Networking (SDN) is an emerging paradigm for network design and management. By providing network programmability and the separation of control and data planes, SDN offers salient features such as simplified and centralized management, reduced complexity, and accelerated innovation. Using SDN, the control and management of network devices are performed by centralized software, called controllers. In particular, Software-Defined Wide Area Networks (SD-WANs) have made considerable headway in recent years. However, SDN can be a double-edged sword with regard to network resilience. The great reliance of SDN on the logically centralized control plane has heightened the concerns of research communities and industries about the resilience of the control plane. Although the controller provides flexible and fine-grained resilience management features that contribute to faster and more efficient failure detection and containment in the network, it is the Achilles' heel of SDN resilience. The resilience of control plane has a great impact on the functioning of the whole system. The challenges associated with the resilience of the control plane should be addressed properly to benefit from SDN's unprecedented capabilities. This dissertation investigates the aforementioned issues by categorizing them into two groups. First, the resilient design of the control plane is studied. The resilience of the control plane is strongly linked to the Controller Placement Problem (CPP), which deals with the positioning and assignment of controllers to the forwarding devices. A resilient CPP needs to assign more than one controller to a switch while it satisfies certain Quality of Service (QoS) requirements. We propose a solution for such a problem that, unlike most of the former studies, takes both the switch-controller/inter-controller latency requirements and the capacity of the controllers into account to meet the traffic loads of switches. The proposed algorithms, one of which has a polynomial-time complexity, adopt a clique-based approach in graph theory to find high-quality solutions heuristically. Second, due to the high dynamics of SD-WANs in terms of variations in traffic loads of switches and the QoS requirements that further affect the incurred load on the controllers, adjustments to the controller placement are inevitable over time. Therefore, resilient switch reassignment and incremental controller placement are proposed to reuse the existing geographically distributed controllers as much as possible or make slight modifications to the controller placement. This assists the service providers in decreasing their operational and maintenance costs. We model these problems as variants of the problem of scheduling on parallel machines while considering the capacity of controllers, reassignment cost, and resiliency (which have not been addressed in the existing research work) and propose approximation algorithms to solve them efficiently. To sum up, CPP has a great impact on the resilience of SDN control plane and subsequently the correct functioning of the whole network. Therefore, tailored mechanisms to enhance the resiliency of the control plane should be applied not only at the design stage of SD-WANs but also during their lifespan to handle the dynamics and new requirements of such networks over time. / Graduate

This thesis presents a 3D stereoscopic interactive fish tank system that combines the 3D stereoscopy and ¡§controller-free¡¨ components. Based on the characteristics of human vision, when seeing the objects, the left eye image and right eye image will be slightly different, one can use the intensity information and the epipolar geometry to proceed matching, and then to generate the 3D depth information. This system allows a user to use gesture to do interaction. It estimates 3D objects depth information, and uses eyes distance, distance between the user and the sensor, disparity map to calculate the virtual objects¡¦ three-dimensional coordinate, and then transforms hand and virtual objects¡¦ coordinate into the same coordinate to allow accurate interaction. The system allows users to experience the innovative multi-media interactive entertainment.

This thesis aims to investigate an active power factor correction (PFC) circuit and its mathematical model, in order to develop a reliable and efficient simulation platform. By using the PI controller, we can control the inductor current and the output voltage of the boost converter. Finally, we constructed the circuit and analyzed the results to verify that our mathematical model is valid.

Abstract The thesis comprises two different IC design projects, which are briefly introduced as follows. The first part is the NIC (Network Interface Controller) design. The NIC implements all of the Media Access Control (MAC) layer functions for transmission and reception of packets in accordance with the IEEE 802.3 standard. The design is compatible with CSMA/CD type Local Area Network, i.e, 100/10 Mbps Ethernet. The second part is a post-amplifier for a 16Mbps infrared transceiver module. We presents a design of the post-amplifier to convert the pre-amplifier output into digital pulses such that the baseband digital codec can further translate the pulses into the format of IrDA protocols. The design of the amplifier is aimed at the VFIR (very fast infrared) which is supposed to provide a 16 Mbps data transmission rate. The circuit design is carried out by TSMC 0.35 um 1P4M CMOS technology. The simulations results of the design meet the required specification of IrDA VFIR.

With the increasing demand for multi-media,multi-core system architecture used in parallel processing of large amounts of data to carry out operations,in the past,large amounts of data is transferred through an independent control of DMA,and often have the following shortcomings,(1)As a result of the transmission of data is completed by reading and writing,caused the burden of memory clock singnal,(2)A large number of occupied bandwidth,caused the collision with processor by using the data bus. Based on the above shortcomings, this paper proposed an internal fast data switching mechanism through AMBA instruction by integrating the memory controller and DMA function. With the high transmission clock rate of DDR2, to achieve (1) transfer data by the original memory clock rate between memory and memory, (2) transmission between memory and device can be reached by bridge of the controller. Can significantly reduce not only the System Bus in the workload and provide the purpose of handling large amounts of data, to reduce the transmission of data on the amount of time spent and release of the right to use the Bus to other peripheral devices and to enhance the efficiency of the overall system.We also achieved the interface of SATA bridge in the controller. Through the DDR2 memory buffer to enhance the efficiency of accessing information and to provide strong type on the data buffer mechanism, can effectively reduce the number of solid-state hard disk access, the extension of its work life. According to the simulation results show that the use of traditional DMA transfer mechanism for the rapid exchange of data, compared to provide a minimum bandwidth in DDR2, you can save about 51% of transmission time, in the DDR2 maximum bandwidth available, you can save 87% of transmission time.

Den här studien undersöker beskrivningar av controllerns roll och dess funktion under tre decennier i Europa. Studien utgår från en systematisk granskning av vetenskapligt granskade artiklar som publicerats i tolv ledande journaler under perioden 1990-2014. Begrepp och funktioner undersöks tillsammans med val av forskningens teoretiska ansatser och metoder. Resultatet i studien visar att det finns tydliga faser av forskningens beskrivningar av controllern, en tidig fas där rollen frigörs från tidigare föreställningar av en ekonom som hanterar redovisning och kassaflöden, en mellanfas där rollen påverkas av exempelvis nya tekniker som IT-stöd och affärssystem leder till att omdefinitioner av rollen anses vara viktiga samt en modern fas där tidigare rolluppdelningar ifrågasätts och fokus ligger på rollens makt i organisationen och möjligheter att skapa sin egen yrkesidentitet. Det finns ett relativt homogent mönster i val av teoretisk ansats gällande beskrivning av controllern. Majoriteten av artiklarna i urvalet utgår från ett sociologiskt perspektiv vilket pekar på att controllern har beskrivits utifrån den kontext controllern verkar i och därmed gett viktiga indikationer för en förståelse av just denna kontext. Studien visar att det framförallt uttrycks att det är organisationella faktorer som driver förändringarna av roll och rollfunktion. Varje organisation definierar vad controllern har för funktion och vilken påverkan denne ska ha på verksamheten. Den kunskapsbas som en controller bör ha, enligt beskrivningarna, visar att controllern behöver hantera fler områden än redovisning. Detta har rapporterats tidigare, men har beskrivits som att det handlar om en rollförändring och en uppdelning av roller. Resultatet i den här studien pekar snarare på att det är en naturlig process av förändring av rollen för ett företags vidare överlevnad. / This study examines the descriptions of the role of management accountants in Europe (available only in Swedish). The study is a systematic literature review of peer-reviewed articles, published in twelve leading journals during 1990-2014. The descriptions of the role are examined in relation to theoretical approaches and methods.   The result indicates that there are three distinct phases of the descriptions of management accountants, from a role that is released from the previous assumptions of an accountant as a bean-counter towards a phase where the role is affected by new technologies that leads to redefinitions of the role, up to today’s phase where previous role types are questioned with a focus on the power position of the role within the organization and opportunities to create a professional identity.   There is a relatively homogeneous pattern in the theoretical approach to the study of the management accountant. The vast majority of articles are based on a sociological perspective, which indicates that the management accountant has been described based on the context the management accountant operates in, given important indications for understanding this particular context.  The study indicates that it is primarily the organizational factors that are driving the changes and the function of the role. Each organization defines the function of a management accountant based on to what extent this function is linked to business. The knowledge base of a management accountant, according to the descriptions, illustrates that the management accountant requires managing more areas than accounting. This has been reported before, but has been explained as a role change and a variety of role types. The results of this study indicate that it is rather a natural process of change in relation to the further survival of a business.

Automated site preparation on the Moon using a group of autonomous rovers is a topic of great interest for the establishment of a lunar base. A potentially very useful system in which multiple, autonomous rovers clear soil to create a landing pad while simultaneously forming berms with the soil cleared will be described. An Artificial Neural Tissue (ANT) architecture was used as the control algorithm to accomplish these tasks. This scalable architecture encourages task decomposition of the main mission tasks and requires minimal human supervision. To solve these tasks, a single fitness function to measure the performance of the controller and a set of allowable basis behaviors was defined. Next, an evolutionary (Darwinian) selection process was used to generate controllers in simulation. The fittest controller was subsequently implemented on LEGO robots for additional validation and testing. The ANT controller was ultimately integrated with a team of three large-scale rovers.