Network processors are custom high performance embedded processors deployed for a variety of tasks that must operate at high line (Gbits/sec) speeds to prevent packet loss. With the increase in complexity of application domains and larger code store on modern network processors, the network processor programming goes beyond simply exploiting parallelism in packet processing. Unlike the traditional homogeneous threading model, modern network processor programming must support heterogenous threads that execute simultaneously on a microengine. In order to support such demands, we first propose hardware management of registers across multiple threads. In their PLDI 2004 paper, Zhuang and Pande for the first time proposed a compiler based scheme to support register allocation across threads; in this work, we extend their static allocation method to support aggressive register allocation taking dynamic context into account. We also remove the load/stores due to aliased memory accesses converting them into register moves exploiting dead registers. This results in tremendous savings in latency and higher throughput mainly due to the removal of high latency accesses as well as idle cycles. The dynamic register allocator is designed to be light-weight and low latency by undertaking many tradeoffs. In the second part of this work, our goal is to design an automatic register allocation scheme that makes compiler transperant to dual bank register file design for network processors. By design network processors mandate that the operands of an instruction must be allocated to registers belonging to two different banks. The key goal in this work is to take into account dynamic contexts to balance the register pressure across the banks. Key decisions made involve, how and where to map incoming virtual register on a physical register in the bank, how to evict dead ones, and how to minimally undertake bank to bank copies and swaps. It is shown that it is viable to solve both of these problems by simple hardware designs that avail of dynamic contexts. The performance gains are substantial and due to simplicity of the designs (which are also off critical paths) such schemes may be attractive in practice.

In this thesis, a multi-rate LDPC (Low-Density Parity-Check code) decoder circuit is proposed for IEEE 802.16e standard. In the proposed circuit, we modify the overlapping structure for different code rate of the LDPC decoder to enhance the hardware utilization ratio and provide flexible parametric design. LDPC decoding is completed by the recursive operations between variable nodes and check nodes. We use Beneš network to implement the wire-routing of the operations between variable nodes and check nodes. However, the decoders with different code rates may result in different Beneš networks and increase the hardware complexity. We propose a modified overlapping structure to reduce the complexity of parallelized Beneš network and to increase the hardware utilization ratio.

Deployment of mobile nodes in a region of interest is a critical issue in building a mobile sensor network because it affects cost and detection capabilities of the system. The deployment of mobile sensors in essence is the movement of sensors from an initial position to a final optimal location. Considerable attention has recently been given to this deployment issue. Many of the distributed deployment schemes use the potential field method. In most cases, the negative gradient of the potential function becomes the feedback control input to a node. This assumes that the potential function is differentiable over the entire region. This assumption is valid primarily when the topology of the network is fixed. In this research, we analyze the stability of a network that uses piecewise smooth potential functions. A gravitation-like force is proposed to deploy a group of agents and to form a certain configuration. We use a nonsmooth version of the Lyapunov stability theory and LaSalle’s invariance principle to show asymptotic stability of the network which is governed by discontinuous dynamics. We propose a hierarchical structure using potential fields for mobile sensor network deployment. A group of mobile nodes first form a cluster using a potential field method and then cluster heads are used to establish a hexagonal structure that employs a higher level potential field. We consider specifically the problem of deploying a mobile sensor network so that a certain area coverage is realized and maintained. And we propose an algorithm for main taining the desired coverage that assumes the availability of a stochastic sensor model. The model reflects the decline of the sensor accuracy as the distance increases from the sensor. It is further assumed that each node’s sensor has a different sensing range to represent sensor performance deterioration due to power decay. The network deployment scheme combines artificial forces with individual sensor ranges. The validity and the effectiveness of the proposed algorithm are compared to the conventional methods in simulations. Simulation results confirm the effectiveness of the proposed algorithms with respect to a defined performance metric.

Polymers are intrinsically poor thermal conductors, which are ideal for thermoelectrics, but low electrical conductivity and thermopower have excluded them as feasible candidates as thermoelectric materials in the past. However, recent progress in polymer technology, particularly nanomaterial-polymer composites, can bring them into degenerate semiconductor or metallic regimes by incorporating a small amount of conductive filler. I demonstrate that such polymer nanocomposites can be viable for light-weight and economical thermoelectrics by using a segregated network approach for the nanocomposite synthesis. The thermoelectric properties were further improved by a change of stabilizer and drying conditions. The thermoelectric properties of the segregated network nanocomposites were measured for carbon nanotubes and the thermoelectric figure of merit, ZT, was calculated at room temperature. The influence on thermoelectric properties from filler concentration, stabilizer materials and drying condition are also discussed.

The rise in the popularity of smartphones such as Blackberry and iPhone creates a strain on the world's mobile networks. The extensive use of these mobile devices leads to increasing congestion and higher rate of node failures. This increasing demand of mobile wireless clients forces network providers to upgrade their wireless networks with more efficient and more reliable services to meet the demands of their customers. Therefore, there is a growing interest in strategies to resolve the problem and reduce the stress on the wireless networks. One strategy to reduce the strain on the wireless networks is to utilize cooperative communication. The purpose of this thesis is to provide more efficient and reliable solutions for direct information exchange problems. First, algorithms are presented to increase the efficiency of cooperative communication in a network where the clients can communicate with each other through a broadcast channel. These algorithms are designed to minimize the total transmission cost so that the communication will be less expensive and more efficient. Second, we consider a setting in which several clients exchange data through a relay. Our algorithms have provable performance guarantees. We also verify the performance of the algorithms in practical settings through extensive simulations.

In recent years, more and more mass mediums mentioned blog, the new individual public mediums in network, and more and more blogger began blogging. They documented their life, expressed deeply felt emotions and provide commentary and opinions in blog. Blog is stage that blogger present self for audience, blogger can transmit image to their audience. But these bloggers express what self-presentation in blog? This research use the concept of self-presentation and analysis of social network, and study the social network is formed with online dairies blog and the self image. we discovered that connection relations centralize in the popular blogs, and the more popular blogs have more indegree. The support of audience is motivation of continue writing for blog. In the dimension of self-presentation, the most self in blog is decorated from real life of blogger. But even blogger can choice to present which image, they still reproduced structure and characteristic of real world in blogoshpere. The research also discovered blogger wish to segregate audience, presented different self before different reader.

This research is to improve the efficiency of present prediction factors. It has been tested that many factors have prediction power toward stocks returns. Although the prediction power is not stable, the factors are still valuable. This research analyzes preceding factors by neural network in order to make better use of these factors. Besides, we examine 15 companies respectively and compare the results between neural network and liner regression of those companies. Data are divided into training period and prediction period. We use data of training period to build up our model and test the model by the data from prediction period to verify the prediction powers of the models. The results show neural network has better solution compared to liner regression in both training and prediction period. Neural network is more precision and has less prediction error.

It¡¦s the age of network now. More and more people use the network and network management becomes important. The ISO sets the network management model: accounting management, configuration management, performance management, fault management and security management. Network topology plays an important role of them. Network topology can help network manager to manage network devices efficiently and to handle some problems. So, topology discovery is an important technology that can help us to find out the network topology. Although there are many network management tools having topology discovery function, they are commercial secret and usually need pay. Because of network topology is important of network management and commercial network management software isn¡¦t free, we want to study topology discovery to find the suitable algorithm of topology discovery which can find out network layer topology and data link layer topology. Then we will modify the algorithm to help us to implement the system of topology discovery. This system needs minor factors and less influence on network. It can discover topology efficiently.

The purpose of this article is try to find the efficient factor that affect corporate's financial structure.

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.