BCF交络技术

本文对BCF交络加工的必要性、交络器的类型、交络结形成的机理及影响交络的因素等问题进行了分析,指出BCF的交络与纺丝工艺条件、丝本身的特性、交络器的结构形状及尺寸有密切关系。在实践中,只有综合考虑上述因素,才能获得优良的BCF交络丝。

合纤交络丝的气流加工

在气流中对合纤丝束进行拉伸的处理方法,是提高其生产和加工效率的方法之一。此过程通常在拉伸机上进行。这时,把丝束放在拉伸盘下方的专用装置中(交络器),如图1所示。将压缩空气垂直地对准丝束。

Study on Multi-stream Heat Exchanger Network Synthesis with Parallel Genetic/Simulated Annealing Algorithm

The multi-stream heat exchanger network synthesis (HENS) problem can be formulated as a mixed integer nonlinear programming model according to Yee et al. Its nonconvexity nature leads to existence of more than one optimum and computational difficulty for traditional algorithms to find the global optimum. Compared with deterministic algorithms, evolutionary computation provides a promising approach to tackle this problem. In this paper, a mathematical model of multi-stream heat exchangers network synthesis problem is setup. Different from the assumption of isothermal mixing of stream splits and thus linearity constraints of Yee et al., non-isothermal mixing is supported. As a consequence, nonlinear constraints are resulted and nonconvexity of the objective function is added. To solve the mathematical model, an algorithm named GA/SA (parallel genetic/simulated annealing algorithm) is detailed for application to the multi-stream heat exchanger network synthesis problem. The performance of the proposed approach is demonstrated with three examples and the obtained solutions indicate the presented approach is effective for multi-stream HENS.

An Explicit Solution for Thermal Calculation and Synthesis of Super-structure Heat Exchanger Networks

For the optimal design of a heat exchanger network,the inlet and outlet stream temperatures of each heat exchanger in the network should be known.An explicit analytical solution of stream temperatures of an arbi-trary connected heat exchanger network was introduced,which is suitable for the thermal calculation of heat ex-changer networks.For the heat exchanger network synthesis,this solution was further developed and coupled with the stage-wise superstructure heat exchanger networks.The new calculation procedure reduced the computer mem-ory requirement dramatically.On the basis of this solution,a mathematical model for synthesis of heat exchanger networks with genetic algorithm was formulated,which is always feasible and no iteration is needed.Two examples were calculated with the proposed approach and better results were obtained.

Modeling and Optimization for Heat Exchanger Networks Synthesis Based on Expert System and Genetic Algorithm

A new superstructure form of heat exchanger networks (HEN) isproposed based on expert system system (ES). The new superstructureform is combined with the practical engineering. The differentinvestment cost formula for Different heat exchanger is alsopresented based on ES. The mathematical model for the simultaneousoptimization Of network configuration is established and solved by agenetic algorithm. This method can deal with larger scale HENsynthesis and the optimal HEN configuration is obtainedautomatically. Finally, a case study is presented to Demonstrate theeffectiveness of the method.

Network Structure Expert System and Operation Optimization

It is proposed that double level programming technique may be adopted in synthesis strategy. Optimization of heat exchanger network structural configuration (the master problem) may be solved at the upper level, leaving the rest operating conditions( the slave problem) being optimized at the lower level. With the uniqueness in mind, an HEN synthesis expert system may be employed to address both the logical constraints and the global operation parameters′ optimization using enhanced sequential number optimization theory.Case studies demonstrate that the synthesis strategy proposed can effectively simplify both the problem solving and the synthesis process. The validity of the strategy recommended is evidenced by case studies′ results compared.

Digital Signal Processing Based Real Time Vehicular Detection System

Traffic monitoring is of major importance for enforcing traffic management policies.To accomplish this task,the detection of vehicle can be achieved by exploiting image analysis techniques.In this paper,a solution is presented to obtain various traffic parameters through vehicular video detection system(VVDS).VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time.This algorithm uses the background differencing method,and vehicles can be detected through luminance difference of pixels between background image and current image.Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy.Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process four-channel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP′s high performance.In the end,VVDS is tested on real-world scenes and experiment results show that the system is both fast and robust to the surveillance of transportation.

Synthesis of Flexible Heat Exchanger Networks with Stream Splits Based on Rangers of Stream Supply Temperatures and Heat Capacity Flowrates

A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly,the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacityflow rates are pretreated; Secondly, several rules are proposed to establish the superstructuremodel of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly,the improving genetic algorithm is applied to solve the mathematical model established at the secondstep effectively, and the original optimal structure of HEN based on the maximum operation limitingcondition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat loadof heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operationcondition between the upper and down bounds of supply temperature and heat capacity flow rates canbe obtained based on the original optimal structure of HEN by means of these rules. A case studydemonstrates the method presented in this paper is effective

Energy-Aware Traffic Routing with Named Data Networking

Greening Internet is an important issue now, which studies the way to reduce the increas- ing energy expenditure. Our work focuses on the network infrastructure and considers its energy awareness in traffic routing. We formulate the model by traffic engineering to achieve link rate a- daption, and also predict traffic matrices to pre- serve network stability. However, we realize that there is a tradeoff between network performance and energy efficiency, which is an obvious issue as Internet grows larger and larger. An essential cause is the huge traffic, and thus we try to fred its so- lution from a novel architecture called Named Data Networking （NDN） which tent in edge routers and can flexibly cache con- decrease the backbone traffic. We combine our methods with NDN, and finally improve both the network performance and the energy efficiency. Our work shows that it is effective, necessary and feasible to consider green- ing idea in the design of future Internet.

The Innovation and Development of Internet of Vehicles

With the advancements in wireless sensor networks, Internet of Vehicles(IOV) has shown great potential in aiding to ease traffic congestion. In IOV, vehicles can easily exchange information with other vehicles and infrastructures, thus, the development of IOV will greatly improve vehicles safety, promote green information consumption and have a profound impact on many industries. The purpose of this paper is to promote the innovation and development of IOV. Firstly, this paper presents general requirements of IOV such as guidelines, basic principles, and the goal of development. Secondly, we analyze critical applications, crucial support, and business model to promote the industrial development of IOV. Finally, this paper proposes some safeguard measures to further promote the development of IOV.

Dynamic Energy Saving Subcarrier, Bit and Power Allocation in OFDMA Relay Networks

To reduce energy consumption while maintaining users＇ Quality of Service （QoS） in Orthogonal Frequency Division Mul- tiplex Access （OFDMA） relay-enhanced net- works, an adaptive energy saving subcarrier, bit and power allocation scheme is presented. The optimal subcarrier, bit and power alloca- tion problems based on discrete adaptive modula- tion and coding scheme have been previously formulated for relay-enhanced networks, and have been reformulated into and solved by integer programming in optimization theory. If the system still has a surplus of subcarriers after resource allocation, we carry out Band- width Exchange （BE） to enable more subcar- riers to participate in transmission to save en- ergy. In addition, as the relay selection scheme is closely linked with heuristic energy saving resource allocation, a relay selection scheme is proposed. Simulation results indicate that the proposed algorithm consumes less energy when transmitting the same number of bits than greedy energy saving schemes, although its spectrum efficiency is worse.

Traffic Signals Control with Adaptive Fuzzy Controller in Urban Road Network

An adaptive fuzzy logic controller (AFC) is presented for the signal control of the urban traffic network. The AFC is composed of the signal control system-oriented control level and the signal controller-oriented fuzzy rules regulation level. The control level decides the signal timings in an intersection with a fuzzy logic controller. The regulation level optimizes the fuzzy rules by the Adaptive Rule Module in AFC according to both the system performance index in current control period and the traffic flows in the last one. Consequently the system performances are improved. A weight coefficient controller (WCC) is also developed to describe the interactions of traffic flow among the adjacent intersections. So the AFC combined with the WCC can be applied in a road network for signal timings. Simulations of the AFC on a real traffic scenario have been conducted. Simulation results indicate that the adaptive controller for traffic control shows better performance than the actuated one.

Multiple Mobile Sinks Data Dissemination Mechanism for Large Scale Wireless Sensor Network

WSN has been developing from traditional environment monitoring applications to the ubiquitous information services such as the Congestion-oriented Intelligent Transportation System （ColTS）. However, the mobility of nodes makes data dissemination a hard nut to crack. In this paper, we propose MSDD, a multiple mobile sinks data dissemination mechanism for solving the dissemination problem. The main ideas of MSDD are constructing a two-tier grid structure by a designated sink, exploiting a hierarchical monitoring mechanism, and employing a global agent to track the sink locations in order to make the emergencies reported to the sinks immediately, In addition, MSDD supports the query-driven data dissemination. Being compared with TTDD, MSDD is theoretically proved to have less communication overhead. We also validate MSDD outperforms TTDD in reliability and the emergency delivery latency bv simulations.

A rapid switching technology of IP data packet based on Multi-Protocol

The rapid development of network raise the role of WAN. As a large-scale backbone network, the failure of network components can lead to huge loss of data and revenue. How to improve the data switching speed and Quality of Service of network data is more and more important problem which Internet Server Provides cared. Multi-Protocol Lable Switching （MPLS） is a new WAN technology which is currently being standardized by IETF. This paper analysise the architecture of MPLS and describe the mechanism of label switching protocol. In addition, this study analyses the encapsulation of data packet at the Label Switching Routers which is on the boundary of MPLS network. A Label Switching Path （LSP） is built by Label Distribute Protocol in core network. A conclution of ＂one time routed, more times switching＂ routed was reached.

Study on WSN Localization Algorithm and Simulation Model for Intelligent Transportation System

This paper conducts research on the algorithm to improve the location of Wireless Sensor Network （WSN） in Intelligent Transportation System （ITS）. The localization algorithm introduced an improved RSSI vehicle localization algorithm based on multi-path effect and Gaussian white noise. The localization results under different values of Gaussian white noise and different density of beacon nodes are analyzes, and Kalman filtering algorithm is introduced to reduce the influence of signal noise. Finally, a simulation model of ITS is developed to test the algorithm based on mixed noise and Kalman filtering algorithm, which is used to simulate the localization of real vehicles. The simulation shows the algorithm has effect to improve location accuracy and to application

A study on synchronization error accumulation over hop count for synchronization scheme of two-way packet exchange

Two-way packet exchange synchronization scheme has been widely used in wireless sensor networks. However, due to the fact that its synchronization error accumulates rapidly over hop count, its applications are greatly restricted. In this paper, the factors that cause the accumulation of synchronization error over hop count are investigated. Theoretical analysis shows that two factors including the clock drift and the asymmetry of two-way packet exchange, have distinct influences on synchronization error between two adjacent nodes. Further, the clock frequency order along synchronization path is found to be vital to the accumulation of synchronization error. The above three factors jointly determine the accumulation of synchronization error over hop count in wireless network. Theoretic results are also verified by three fine-grained experiments on wireless sensor network testbed. The conclusions can be used to decrease synchronization error for large-scale wireless network by careful network deployment.

A time domain multiple-CFOs and CIRs estimation algorithm over wireless multimedia sensor networks

Channel parameters estimation in an orthogonal for the receiver station is a multi-dimensional （MD） frequency division multiple access （OFDMA） system optimization problem, because every user node has a separate local oscillator and every transmitter to receiver link has individual carrier frequency offset （CFO） and channel impulse response （CIR） parameters. In order to reduce the computational complexity for MD optimization, a time domain CFOs and CIRs estimation algorithm over the OFDMA based wireless multimedia sensor networks （WMSN） is proposed in this paper. In this algorithm, the receiver station can decouple the signal from every node by correlation based on specially designed training sequences, so that the MD optimization problem is simplified to an 1-D optimal problem. It is proved that the multiple CFOs can be identified from the correlation result using the phase shift of the consecutive training se- quences. Based on the CFOs estimation result, the CIRs can then he estimated according to the minimum mean square error （MMSE） criterion. The theoretic analysis and simulation results show that the proposed algorithm can effectively decouple the signal from different user nodes and the bit error rate （BER） per- formance curves are close to the ideal estimation when the user number is not large.

PERFORMANCE EVALUATION FOR DAMPING CONTROLLERS OF POWER SYSTEMS BASED ON MULTI-AGENT MODELS

This paper proposes a multi-layer multi-agent model for the performance evaluation of powersystems,which is different from the existing multi-agent ones.To describe the impact of the structureof the networked power system,the proposed model consists of three kinds of agents that form threelayers:control agents such as the generators and associated controllers,information agents to exchangethe information based on the wide area measurement system (WAMS) or transmit control signals tothe power system stabilizers (PSSs),and network-node agents such as the generation nodes and loadnodes connected with transmission lines.An optimal index is presented to evaluate the performance ofdamping controllers to the system's inter-area oscillation with respect to the information-layer topology.Then,the authors show that the inter-area information exchange is more powerful than the exchangewithin a given area to control the inter-area low frequency oscillation based on simulation analysis.