计算机网络配棉系统设计

介绍了基于计算机网络配棉系统的设计。计算机网络配棉系统包括计算机网络设计、原棉基础数据的采集、数据库设计、配棉系统设计和编程关键算法。采用计算机网络配棉系统,可以大大缩短配棉的时间,提高配棉的效率,克服计算工作量大和因人而异的经验误差等弊病,实现配棉过程的科学管理,降低用棉成本。     

Comparison of Methods for Path Flow Reassignment for Dynamic User Equilibrium

Models to describe or predict of time-varying traffic flows and travel times on road networks are usually referred to as dynamic traffic assignment (DTA) models or dynamic user equilibrium (DUE) models. The most common form of algorithms for DUE consists of iterating between two components namely dynamic network loading (DNL) and path inflow reassignment or route choice. The DNL components in these algorithms have been investigated in many papers but in comparison the path inflow reassignment component has been relatively neglected. In view of that, we investigate various methods for path inflow reassignment that have been used in the literature. We compare them numerically by embedding them in a DUE algorithm and applying the algorithm to solve DUE problems for various simple network scenarios. We find that the choice of inflow reassignment method makes a huge difference to the speed of convergence of the algorithms and, in particular, find that ??travel time responsive?? reassignment methods converge much faster than the other methods. We also investigate how speed of convergence is affected by the extent of congestion on the network, by higher demand or lower capacity. There appears to be much scope for further improving path inflow reassignment methods.     

Analysis of Shortest Paths and Subscriber Line Lengths in Telecommunication Access Networks

We consider random geometric models for telecommunication access networks and analyse their serving zones which can be given, for example, by a class of so-called Cox–Voronoi tessellations (CVTs). Such CVTs are constructed with respect to locations of network components, the nucleii of their induced cells, which are scattered randomly along lines induced by a Poisson line process. In particular, we consider two levels of network components and investigate these hierarchical models with respect to mean shortest path length and mean subscriber line length, respectively. We explain point-process techniques which allow for these characteristics to be computed without simulating the locations of lower-level components. We sustain our results by numerical examples which were obtained through Monte Carlo simulations, where we used simulation algorithms for typical Cox–Voronoi cells derived in a previous paper. Also, briefly, we discuss tests of correctness of the implemented algorithms. Finally, we present a short outlook to possible extensions concerning multi-level models and iterated random tessellations.     

Stochastic routing in ad-hoc networks

We investigate a network routing problem where a probabilistic local broadcast transmission model is used to determine routing. We discuss this model's key features, and note that the local broadcast transmission model can be viewed as soft handoff for an ad-hoc network. We present results showing that an index policy is optimal for the routing problem. We extend the network model to allow for control of transmission type, and prove that the index nature of the optimal routing policy remains unchanged. We present three distributed algorithms which compute an optimal routing policy, discuss their convergence properties, and demonstrate their performance through simulation.     

高速计算机网络中拥塞控制系统设计方法综述

未来的计算机网络将是一种能够提供多种不同 服务,以支持多种不同应用需求,有着集成服务支持能力的高速分组交换网络．为充分提高 该类网络性能,设计一个高效的拥塞控制系统是一个关键问题;而速率调节算法的设计好坏 直接影响拥塞控制系统的性能．为此,本文以ATM网络中的相关研究为背景,首次从控制理 论的角度系统地分析和论述了高速网络中拥塞控制系统的组成并着重分析了其速率调节算法 的设计方法．对目前已经提出的各种典型速率调节算法进行了对比分析和分类阐述,为进一 步研究提出了新的课题和思路．     

Optimal distribution of a hierarchy of network management agents

In this paper, we consider several mathematical and algorithmic problems which arise naturally in the optimal deployment of modern network management systems. Specifically, we will consider the problem of minimizing the total communication costs within an architecture consisting of a distributed hierarchy of cooperating intelligent agents. We consider several communication cost models, and describe provable optimal schemes for distributing agents among machines in each of these models.     

Occlusion filling in stereo: Theory and experiments

A number of stereo matching algorithms have been developed in the last few years, which also have successfully detected occlusions in stereo images. These algorithms typically fall short of a systematic study of occlusions; they predominantly emphasize matching and regard occlusion filling as a secondary operation. Filling occlusions, however, is useful in many applications such as image-based rendering where 3D models are desired to be as complete as possible. In this paper, we study occlusions in a systematic way and propose two algorithms to fill occlusions reliably by applying statistical modeling, visibility constraints, and scene constraints. We introduce a probabilistic, model-based filling order of the occluded points to maintain consistency in filling. Furthermore, we show how an ambiguity in the interpolation of the disparity value of an occluded point can safely be avoided using color homogeneity when the point’s neighborhood consists of multiple scene surfaces. We perform a comparative study and show that statistically, the new algorithms deliver good quality results compared to existing algorithms.     

Decomposition Approaches for Constrained Spatial Auction Market Problems

We consider several equilibrium formulations for the problem of managing spatially distributed auction markets of a homogeneous commodity, which are joined by transmission lines in a network. At each market, traders and buyers are determined by their price functions and choose their offer/bid values. We present equivalent variational inequality, optimization, and saddle point formulations of this problem. The corresponding models possess a special structure of constraint and cost functions and lead to different decomposition schemes. We propose proximal and splitting type methods and discuss their properties and preliminary computational results.     

Rectilinear Partitioning of Irregular Data Parallel Computations

This paper describes new mapping algorithms for domain-oriented data-parallel computations, where the workload is distributed irregularly throughout the domain, but exhibits localized or rectilinear communication patterns. We consider the problem of partitioning the domain for parallel processing in such a way that the workload on the most heavily loaded processor is minimized, subject to the constraint that the partition be perfectly rectilinear. Rectilinear partitions are useful on architectures that have a fast local mesh network and a relatively slower global network; these partitions heuristically attempt to maximize the fraction of communication carried by the local network. We provide an improved algorithm for finding the optimal partition in one dimension, propose new algorithms for partitioning in two dimensions, and show that optimal partitioning in three dimensions is NP-complete. We discuss our application of these algorithms to real problems.     

Computing Equilibria in General Equilibrium Models via Interior-point Methods

In this paper we study new computational methods to find equilibria in generalequilibrium models. We first survey the algorithms to compute equilibria thatcan be found in the literature on computational economics and we indicate howthese algorithms can be improved from the computational point of view. We alsoprovide alternative algorithms that are able to compute the equilibria in anefficient manner even for large-scale models, based on interior-point methods.We illustrate the proposed methods with some examples taken from theliterature on general equilibrium models.     

Real-time scheduling by parallel and distributed simulation over IP Multicast

Scheduling optimization of manufacturing processes becomes more and more important. Complex models with a lot of constraints cause a higher computational effort of the simulation. Optimization cycles of heuristic optimization algorithms like genetic algorithms or local search strategies can easily be scheduled in parallel. But recurrent requirements are the distribution of the model, the interchange of the parameters and results. The IP Multicast architecture is an ideal platform for distributing model data over the network. It reduces the network overhead for sending the model to different clients and simplifies also the initial setup between client and server. The client and the server are able to find each other automatically by preconcerted multicast channels. The developed test implementation is designed to work with the simulation system simcron MODELLER and will be used to handle typical optimization tasks like the weekly demand plan of a back-end process or optimal batch sizes for burn-in ovens. It is also suitable for educational purposes and we use it in practical courses where students learn more about factory scheduling. The system offers a high reusability for any operating sequence optimization problem in electronic or semiconductor manufacturing industry, as well as in other fields.     

Minimalism Distribution Supermodularity

We have designed and implemented multi-agent strategies for manipulation tasks by distributing mechanically-based sequential algorithms across several autonomous spatially-separated agents, such as mobile robots. Our experience using mobile robots for the manipulation of large objects (couches, boxes, file cabinets, etc.) leads us to recommend a minimalist architecture for multi-agent programming. In particular, our methodology has led us to derive asynchronous distributed strategies that require no direct communication between agents, and very sparse geometric and dynamic models of the objects our robots manipulate. We argue for a design principle called supermodularity, which is orthogonal both to the notion of modularity in cognitive AI and also to horizontal decomposition (the non-modularity advocated in the subsumption/connectionist literature.) Finally, we discuss a simple mobotscheme infrastructure to implement supermodular architectures. In the past few years we have programmed many supermodular manipulation protocols and tested them extensively on our team of mobile robots. We describe why we think the supermodular infrastructure results in robust, simple, readable, manipulation strategies that can be recycled and reused.     

无线传感器网络中的调度算法研究

无线传感器网络调度算法通过合理分配节点数据采集和传输的时间,使其在不需要工作时转入低功耗的休眠模式,在满足应用要求服务质量的前提下,高效利用节点能量,达到延长网络生存期的目的.本文介绍了无线传感器网络调度算法的性能评价标准和分类方法,着重讨论了一些典型的调度算法,最后进行了各种算法的比较性总结,并指出了一些亟待解决的问题.     

Fast interference detection between geometric models

We present efficient algorithms for interference detection between geometric models described by linear or curved boundaries and undergoing rigid motion. The set of models include surfaces described by rational spline patches or piecewise algebraic functions. In contrast to previous approaches, we first describe an efficient algorithm for interference detection between convex polytopes using coherence and local features. Then an extension using hierarchical representation to concave polytopes is presented. We apply these algorithms along with properties of input models, local and global algebraic methods for solving polynomial equations, and the geometric formulation of the problem to devise efficient algorithms for convex and nonconvex curved objects. Finally, a scheduling scheme to reduce the frequency of interference detection in large environments is described. These algorithms have been successfully implemented and we discuss their performance in various environments.     

基于路径计算的配电网网架规划

提出了一种配电网网架规划的方法。通过计算供电范围内的路径数，将负荷点分配到路径上，较好地解决了使用遗传算法时难以进行编码的问题。在辐射状网架规划完成后，计算待规划区域的路径矩矩阵，该矩阵反应了配电网联络线的建设费用。在此基础上，进行配电网的联络线优化，实现中压配电网闭环设计的要求。     

Quantized consensus

We study the distributed averaging problem on arbitrary connected graphs, with the additional constraint that the value at each node is an integer. This discretized distributed averaging problem models several problems of interest, such as averaging in a network with finite capacity channels and load balancing in a processor network.We describe simple randomized distributed algorithms which achieve consensus to the extent that the discrete nature of the problem permits. We give bounds on the convergence time of these algorithms for fully connected networks and linear networks.     

Multi-View AAM Fitting and Construction

Active Appearance Models (AAMs) are generative, parametric models that have been successfully used in the past to model deformable objects such as human faces. The original AAMs formulation was 2D, but they have recently been extended to include a 3D shape model. A variety of single-view algorithms exist for fitting and constructing 3D AAMs but one area that has not been studied is multi-view algorithms. In this paper we present multi-view algorithms for both fitting and constructing 3D AAMs. Fitting an AAM to an image consists of minimizing the error between the input image and the closest model instance; i.e. solving a nonlinear optimization problem. In the first part of the paper we describe an algorithm for fitting a single AAM to multiple images, captured simultaneously by cameras with arbitrary locations, rotations, and response functions. This algorithm uses the scaled orthographic imaging model used by previous authors, and in the process of fitting computes, or calibrates, the scaled orthographic camera matrices. In the second part of the paper we describe an extension of this algorithm to calibrate weak perspective (or full perspective) camera models for each of the cameras. In essence, we use the human face as a (non-rigid) calibration grid. We demonstrate that the performance of this algorithm is roughly comparable to a standard algorithm using a calibration grid. In the third part of the paper, we show how camera calibration improves the performance of AAM fitting. A variety of non-rigid structure-from-motion algorithms, both single-view and multi-view, have been proposed that can be used to construct the corresponding 3D non-rigid shape models of a 2D AAM. In the final part of the paper, we show that constructing a 3D face model using non-rigid structure-from-motion suffers from the Bas-Relief ambiguity and may result in a “scaled” (stretched/compressed) model. We outline a robust non-rigid motion-stereo algorithm for calibrated multi-view 3D AAM construction and show how using calibrated multi-view motion-stereo can eliminate the Bas-Relief ambiguity and yield face models with higher 3D fidelity. Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.     

Lexical and pragmatic disambiguation and re-interpretation in connectionist networks

Lexical and pragmatic ambiguity is a major source of uncertainty in natural language understanding. Symbolic models can make high-level inferences necessary for understanding text, but handle ambiguity poorly, especially when later context requires a re-interpretation of the input. Structured connectionist networks, on the other hand, can use their graded levels of activation to perform lexical disambiguation, but have trouble performing the variable bindings and inferencing necessary for language understanding. We have previously described a structured connectionist model, ROBIN, which overcomes many of these problems and allows the massively-parallel application of a large class of general knowledge rules. This paper describes how ROBIN uses these abilities and the contextual evidence from its semantic networks to disambiguate words and infer the most plausible plan/goal analysis of the input, while using the same mechanism to smoothly re-interpret the input if later context makes an alternative interpretation more likely. We present several experiments illustrating these abilities and comparing them to those of other connectionist models, and discuss several directions in which we are extending the model.     

TDD/CDMA系统动态信道分配技术研究

该文在分析TD-SCDMA系统无线资源管理机制的基础上,对该系统的动态信道分配算法进行研究。首先对现有的TDD-CDMA系统中的各种动态信道分配算法进行分类总结和分析比较,并在此基础了给出针对TD-SCDMA系统的慢速信道分配算法、快速信道分配算法以及考虑空间分布信息的信道分配方案,阐明了各自的特点和适用范围。研究了在TDD CDMA系统中如何进一步提高信道利用率的问题。     

Macro-star networks: efficient low-degree alternatives to stargraphs

We propose a new class of interconnection networks, called macro-star networks, which belong to the class of Cayley graphs and use the star graph as a basic building module. A macro-star network can have node degree that is considerably smaller than that of a star graph of the same size, and diameter that is sublogarithmic and asymptotically within a factor of 1.25 from a universal lower bound (given its node degree). We show that algorithms developed for star graphs can be emulated on suitably constructed macro-stars with asymptotically optimal slowdown. This enables us to obtain through emulation a variety of efficient algorithms for the macro-star network, thus proving its versatility. Basic communication tasks, such as the multimode broadcast and the total exchange, can be executed in macro-star networks in asymptotically optimal time under both the single-port and the all-port communication models. Moreover, no interconnection network with similar node degree can perform these communication tasks in time that is better by more than a constant factor than that required in a macro-star network. We show that macro-star networks can embed trees, meshes, hypercubes, as well as star, bubble-sort, and complete transposition graphs with constant dilation. We introduce several variants of the macro-star network that provide more flexibility in scaling up the number of nodes. We also discuss implementation issues and compare the new topology with the star graph and other popular topologies