As digital systems continue to grow in complexity, the design of conventional synchronous systems is facing unprecedented challenges. The number of transistors on individual chips is already in the multi-billion range, and a greatly increasing number of components are being integrated onto a single chip. As a consequence, modern digital designs are under strong time-to-market pressure, and there is a critical need for composable design approaches for large complex systems. In the past two decades, networks-on-chip (NoC’s) have been a highly active research area. In a NoC-based system, functional blocks are first designed individually and may run at different clock rates. These modules are then connected through a structured network for on-chip global communication. However, due to the rigidity of centrally-clocked NoC’s, there have been bottlenecks of system scalability, energy and performance, which cannot be easily solved with synchronous approaches. As a result, there has been significant recent interest in combing the notion of asynchrony with NoC designs. Since the NoC approach inherently separates the communication infrastructure, and its timing, from computational elements, it is a natural match for an asynchronous paradigm. Asynchronous NoC’s, therefore, enable a modular and extensible system composition for an ‘object-orient’ design style. The thesis aims to significantly advance the state-of-art and viability of asynchronous and globally-asynchronous locally-synchronous (GALS) networks-on-chip, to enable high-performance and low-energy systems. The proposed asynchronous NoC’s are nearly entirely based on standard cells, which eases their integration into industrial design flows. The contributions are instantiated in three different directions. First, practical acceleration techniques are proposed for optimizing the system latency, in order to break through the latency bottleneck in the memory interfaces of many on-chip parallel processors. Novel asynchronous network protocols are proposed, along with concrete NoC designs. A new concept, called ‘monitoring network’, is introduced. Monitoring networks are lightweight shadow networks used for fast-forwarding anticipated traffic information, ahead of the actual packet traffic. The routers are therefore allowed to initiate and perform arbitration and channel allocation in advance. The technique is successfully applied to two topologies which belong to two different categories – a variant mesh-of-trees (MoT) structure and a 2D-mesh topology. Considerable and stable latency improvements are observed across a wide range of traffic patterns, along with moderate throughput gains. Second, for the first time, a high-performance and low-power asynchronous NoC router is compared directly to a leading commercial synchronous counterpart in an advanced industrial technology. The asynchronous router design shows significant performance improvements, as well as area and power savings. The proposed asynchronous router integrates several advanced techniques, including a low-latency circular FIFO for buffer design, and a novel end-to-end credit-based virtual channel (VC) flow control. In addition, a semi-automated design flow is created, which uses portions of a standard synchronous tool flow. Finally, a high-performance multi-resource asynchronous arbiter design is developed. This small but important component can be directly used in existing asynchronous NoC’s for performance optimization. In addition, this standalone design promises use in opening up new NoC directions, as well as for general use in parallel systems. In the proposed arbiter design, the allocation of a resource to a client is divided into several steps. Multiple successive client-resource pairs can be selected rapidly in pipelined sequence, and the completion of the assignments can overlap in parallel. In sum, the thesis provides a set of advanced design solutions for performance optimization of asynchronous and GALS networks-on-chip. These solutions are at different levels, from network protocols, down to router- and component-level optimizations, which can be directly applied to existing basic asynchronous NoC designs to provide a leap in performance improvement.

Song Lihua. / "September 2000." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 93-[98]). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Xie, Zhenchang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (p. 48-50). / Abstracts in English and Chinese. / Abstract --- p.ii / Table of Contents --- p.v / List of Figures --- p.vi / List of Tables --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Development of fiber optic networks --- p.1 / Chapter 1.2 --- Optical transmission system --- p.2 / Chapter 1.3 --- The motivation of this thesis --- p.7 / Chapter 1.4 --- Outline of this thesis --- p.8 / Chapter Chapter 2 --- The Consolidation of Two Coexisting Networks with Full-Interconnection --- p.10 / Chapter 2.1 --- Assumptions and problem formulation --- p.10 / Chapter 2.2 --- Definitions and notations --- p.12 / Chapter 2.3 --- An algorithm to derive Lmin --- p.13 / Chapter 2.4 --- Example illustrations --- p.17 / Chapter 2.5 --- "The number of fiber links required over the number of nodes of a network, L/N" --- p.21 / Chapter 2.6 --- Summary --- p.22 / Chapter Chapter 3 --- The Consolidation of Two Coexisting Networks with Two Interconnection Links --- p.23 / Chapter 3.1 --- Assumptions --- p.24 / Chapter 3.2 --- Analysis on the optimal location of the two interconnection links --- p.25 / Chapter 3.3 --- Notations --- p.25 / Chapter 3.4 --- Theorems and corollaries --- p.25 / Chapter 3.5 --- "The number of fiber links required over the number of nodes of a network, L/N" --- p.35 / Chapter 3.6 --- Summary --- p.36 / Chapter Chapter 4 --- Protection of the Consolidated Network --- p.37 / Chapter 4.1 --- Full-interconnection case --- p.38 / Chapter 4.2 --- Two interconnection case --- p.39 / Chapter 4.3 --- Summary --- p.44 / Chapter Chapter 5 --- Summary and Future Works --- p.45 / Chapter 5.1 --- Summary --- p.45 / Chapter 5.2 --- Future works --- p.47 / Bibliography --- p.48 / Appendix ´ؤ List of publications --- p.52

This thesis focuses on efficient provisioning of resilient Virtual Private Network (VPN) services. It first confirms the intuition that network resources can be more efficiently utilized when resilience mechanisms are implemented by a network provider in the physical network than by its VPN customers in their VPNs. Next, a Multiprotocol Label Switching-based programmable VPN architecture is presented that delivers virtual links as resilient quality of service (QoS) connections and virtual sites. Virtual sites allow customers to implement functionality like customized routing and content adaptation ???in the cloud???, as opposed to the current network model where all functionality is implemented at the network edge. To provision a resilient QoS connection, two paths need to be computed from the ingress to the egress nodes, such that both paths meet the given QoS constraints. Two different frameworks have been proposed in the literature to compute resilient QoS connections when the QoS constraints are bandwidth and end-to-end delay. They both use a preprocessing step whereby either all links with less residual capacity than the given bandwidth constraint are pruned, or the given end-to-end delay is converted to an effective bandwidth. The frameworks thus reduce the problem to one with only a single constraint. We argue in this thesis that these frameworks individually lead to poor network utilization and propose a new framework where both constraints are considered simultaneously. Our framework exploits the dependency between endto- end delay, provisioned bandwidth and chosen path through using the provisioned bandwidth as a variable. Here, two link-disjoint paths are computed together with their respective minimum bandwidths such that both the bandwidth and end-to-end delay constraints are satisfied. Given our framework we first propose a new generic algorithm that decomposes the problem into subproblems where known algorithms can be applied. Then we propose two new linear programming (LP) formulations that return the two paths and their respective bandwidths such that they have the minimum combined cost. To make our framework applicable in a production environment, we develop two new algorithms with low run times that achieve even higher network performance than their LP formulation counterpart. These algorithms systematically use an algorithm that computes non-resilient QoS connections. As no algorithm for computing nonresilient QoS connections with sufficiently low run time has been proposed in the current literature we develop two new algorithms and their respective heuristics with a run time comparable to Dijkstra???s shortest-path algorithm. Our simulations show that exploiting the dependency between end-to-end delay, provisioned bandwidth and chosen path can significantly improve the network performance.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 4, 2007) Includes bibliographical references (p. 74-80).

MANETs are known to be useful in situations where mobile nodes need to communicate and coordinate in dynamic environments with no access to fixed network infrastructure. However, connectivity problems can occur when sub-groups within a MANET move out of communication range from one another. The increasingly prolific use of UAVs in military and civilian contexts suggests that UAVs may be very useful for facilitating connectivity between otherwise disconnected mobile nodes. Network Centric Warfare (NCW) theory makes heavy use of MANETs, and UAVs also fit well into the NCW theory; this paper describes the work involved in integrating network enabled UAVs into a previously-developed simulation of ground troop mobility called UMOMM. Specifically, we created a simple decision model for constrained, constant-radius UAV movements, and developed a target-based method by which UAVs can distribute themselves in order to improve the connectivity of the ground members of the MANET. / Graduation date: 2012

The most important part of parallel computation is communication. Except in the most embarassingly parallel examples, processors cannot work cooperatively to solve a problem unless they can communicate. One way to solve the problem of communication is to use an interconnection network. Processors are located at nodes of the network, which are joined by communication channels. Desirable aspects of an interconnection network include low maximum and average routing distances (as measured in the number of communication channels crossed), a large number of processors, and low number of communication channels per processor. A number of published networks are created from the hypercube by rearranging the hypercube's communication links in a systematic way [23] [28] [30] [33] [50]. These networks maintain the same number of processors, communication links, and links per processor as the hypercube, but have dramatically smaller maximum and average routing distances. This thesis derives one formal mathematical description for this family of networks. This formal description is used to derive graph-theoretic properties of existing networks, and to design new networks. The description is also used to design generalized routing and other communications algorithms for these networks, and to show that these networks can embed and simulate other standard networks, for instance, ring and mesh networks. A network simulator is used to model the dynamic behavior of this family of networks under both store-and-forward and wormhole routing strategies for message-passing. The simulation results are used to study and compare the networks' behavior under various message-passing loads, and to determine what properties are desirable in a network that exists in this model. / Graduation date: 1995

The development of cDNA microarray technology has made it possible to simultaneously monitor the expression status of thousands of genes. A natural use for this vast amount of information would be to try and figure out inter-gene relationships by studying the gene expression patterns across different experimental conditions and to build Gene Regulatory Networks from these data. In this thesis, we study some of the issues involved in Genetic Regulatory Networks. One of them is to discover and elucidate multivariate logical predictive relations among gene expressions and to demonstrate how these logical relations based on coarse quantization closely reflect corresponding relations in the continuous data. The other issue involves construction of synthetic Probabilistic Boolean Networks with particular attractor structures. These synthetic networks help in testing of various algorithms like Bayesian Connectivity based approach for design of Probabilistic Boolean Networks.

This thesis work researches the theory and application of systems performing omnidirectional, non-direct path optical data communication (ONP systems). Such systems are characterized by 1) the communication involves a local, usually circular area; 2) Obstacles are allowed between a transmitter and the receivers. This is in contrast to the point-to-point and line-of-sight communications performed by almost all existing infrared data communication or transmission systems. The elimination of the point-to-point limitation makes ONP systems suitable for optical local area networking. The feasibility of ONP systems employing infrared LEDs and silicon photo detectors has been analyzed and the performance of such systems predicted. The analysis shows that indoor ONP systems are both feasible and practical. Only a few LEDs are required to cover the entire area of a large room. Efforts have been made in finding rules for optimal design of the ONP systems. A set of design criteria and curves have been established. The theoretical analysis has been verified in a successful experiment done with OptoNet, an ONP infrared datalink for local area networks. This experimental system consists of two identical communication units employing FSK modulation and microprocessor controllers. The experiment has demonstrated that the ONP optical data communications can be realized by relatively simple electronic hardware. / Graduation date: 1991

Computational gene regulation models provide a means for scientists to draw biological inferences from large-scale gene expression data. The expression data used in the models usually are obtained in a time series in response to an initial perturbation. The common objective is to reverse engineer the internal structure and function of the genetic network from observing and analyzing its output in a time-based fashion. In many studies (Wang [39], Resendis-Antonio [31]), each gene is considered to have a regulatory effect on another gene. A network association is created based on the correlation of expression data. Highly correlated genes are thought to be co-regulated by similar (if not the same) mechanism. Gene co-regulation network models disregard the cascading effects of regulatory genes such as transcription factors, which could be missing in the expression data or are expressed at very low concentrations and thus undetectable by the instrument. As an alternative to the former methods, some authors (Wu et al. [40], Rangel et al. [28], Li et al. [20]) have proposed treating expression data solely as observation values of a state-space system and derive conceptual internal regulatory elements, i.e. the state-variables, from these measurements. This approach allows one to model unknown biological factors as hidden variables and therefore can potentially reveal more complex regulatory relations.<p>In a preliminary portion of this work, two state-space models developed by Rangel et al. and Wu et al. respectively were compared. The Rangel model provides a means for constructing a statistically reliable regulatory network. The model is demonstrated on highly replicated Tcell activation data [28]. On the other hand, Wu et al. develop a time-delay module that takes transcriptional delay dynamics into consideration. The model is demonstrated on non-replicated yeast cell-cycle data [40]. Both models presume time-invariant expression data. Our attempt to use the Wu model to infer small gene regulatory network in yeast was not successful. Thus we develop a new modeling tool incorporating a time-lag module and a novel method for constructing regulatory networks from non-replicated data. The latter involves an alternative scheme for determining network connectivity. Finally, we evaluate the networks generated from the original and extended models based on a priori biological knowledge.