在TCP/IP协议支撑之上的Windows Socket应用开发

Ｉｎｔｅｒｎｅｔ日益成为信息时代的支住产业,它所采用的协议就是著名的ＴＣＰ／ＩＰ协议。Ｗｉｎｄｏｗｓ Ｓｏｃｋｅｔ（简称ＷｉｎＳｏｃｋ）是在Ｗｉｎｄｏｗｓ平台下用ＴＣＰ／ＩＰ协议开发网络应用程序的编程接口。本文将详细介绍在ＴＣＰ／ＩＰ协议支撑之上的ＷｉｎＳｏｃｋ编程接口原理以及利用ＷｉｎＳｏｃｋ开发网络应用程序的流程、技术。     

Visual Basic中的TCP程序设计

ＴＣＰ／ＩＰ是国际互连网络的标准通信协议，也是用来开发Ｃ／Ｓ应用的主要协议。如何进行基于ＴＣＰ／ＩＰ协议的软件开发，是开发Ｃ／Ｓ应用和其它网络应用的基础上。本文向读者介绍Ｖｉｓｕａｌ Ｂａｓｉｃ中的Ｗｉｎｓｏｃｋ控制和利用Ｗｉｎｓｏｃｋ控件进行ＴＣ程序设计的方法。     

MFC下实现局域网内部数据传送

１套接字编程概述 套接字（ｓｏｃｋｅｔ）最初是由加州大学Ｂｅｒｋｅｌｅｙ学院为ＵＮＩＸ操作系统开发的基于 ＴＣＰ／ＩＰ协议的网络通信接口,随着ＵＮＩＸ操作系统的广泛使用,套接字成为当前最流行的网络通信应用程序接口之一。 Ｗｉｎｄｏｗｓ Ｓｏｃｋｅｔｓ是 Ｂｅｒｋｅｌｅｙ Ｓｏｃ－ｋｅｔｓ在Ｗｉｎｄｏｗｓ环境下的移植,它包括一个标准的ＢｅｒｋｅｌｅｙＳｏｃｋｅｔｓ功能调用的集合,以及为Ｗｉｎｄｏｗｓ 所作的重要扩充。 ＭＦＣ通过两个类ＣＡｓｙｎｃＳｏｃｋｅｔ和ＣＳｏｃｋｅｔ对ＷｉｎｓｏｃｋｅｔＡＰＩ进行了…     

IP网络通信规范Windows Socket的开发

ＴＣＰ／Ｐ是网络中应用最广泛的协议，ＷｉｄｏｗｓＳｏｃｋｅｔｓ是基于ＴＣＰ／ＩＰ的应用程序标准规范。本文重点介绍了ＴＣＰ／ＩＰ的基本原理、概念以及ＷｉｎｄｏｗｓＳｏｃｋｅｔ编程的基本方法。     

解决Socks5代理服务器因进程过多而无法运行的问题

对于教育网和１６９的大部份用户来说,如果他们要到其所在的局域网以外的地方访问ＩＮＴＥＲＮＥＴ上的资源,都要通过某一种代理服务器的帮助才能实现。 代理服务器有好几种,其中Ｓｏｃｋｓ５代理服务器上运行的Ｓｏｃｋｓ５代理是目前最优秀的代理之一。它可以让几乎所有基于ＴＣＰ／ＩＰ 协议和ＵＤＰ协议的软件都能使用Ｓｏｃｋｓ５代理出去访问ＩＮＴＥＲＮＥＴ。Ｓｏｃｋｓ５还支持各种身份验证研制,服务器端域名解析,这很好地解决了认证、保密、以及ｐｒｏｘｙ接力等问题。 Ｓｏｃｋｓ５在协议栈的ＴＣＰ层上运行,它不要求应用…     

CSCW网络安全问题探讨

该文从不同角度探讨ＣＳＣＷ系统的网络安全问题。分析ＣＳＣＷ网络安全策略;简述Ｉｎｔｅｒｎｅｔ网上常用的基于路由器及路由协议、ＲＡＤＩＵＳ（ＲｅｍｏｔｅＡｕｔｈｅｎｔｉｃａｔｉｏｎＤｉａｌＩｎＵｓｅｒＳｅｒｖｉｃｅ）、身份认证（Ａｕｔｈｅｎｔｉｃａｔｉｏｎ）、访问控制（ＡｃｃｅｓｓＣｏｎｔｍｌ）、加密（Ｅｎｃｒｙｐｔｉｏｎ）、代理服务器（ＰｒｏｘｙＳｅｒｖｅｒ）、Ｗｅｂ服务器的安全机制、虚拟局域网ＶＬＡＮ（ＶｉｒｔｕａｌＬｏｃａｌＡｒｅａＮｅｔｗｏｒｋ）技术、网络管理及检测等提高网络性能和安全的重要技术;最后,给出一个可供参考的广域ＣＳＣＷ系统的网络结构及安全管理机制。     

网络环境下基于Winsock的进程通信方法

１ 引言 ＴＣＰ／ＩＰ协议由操作系统内部实现,编程人员要开发ＴＣＰ／ＩＰ应用程序,就要利用ＴＣＰ／ＩＰ提供的编程接口──Ｓｏｃｋｅｔ（套接字）。基于ＴＣＰ／ＩＰ的Ｓｏｃｋｅｔ通用编程接口最初由ＵＮＩＸ操作系统开发。随着微机应用越来越广泛,Ｗｉｎｄｏｗｓ系列成为微机上最常用的一种操作系统,在９０年代初,国际上著名的一些软件公司共同制定了一套标准,即 Ｗｉｎｄｏｗｓ Ｓｏｃｋｅｔｓ规范,简称Ｗｉｎｓｏｃｋ,把Ｓｏｃｋｅｔ机制引入了Ｗｉｎｄｏｗｓ,由于Ｗｉｎｄｏｗｓ操作系统与ＵＮＩＸ系统任务调度方式的区别…     

CISOC-SARRS──Application to Rational Design of Organic Solvent Extractants

ＣＩＳＯＣ－ＳＡＲＲＳ──ＡｐｐｌｉｃａｔｉｏｎｔｏＲａｔｉｏｎａｌＤｅｓｉｇｎｏｆＯｒｇａｎｉｃＳｏｌｖｅｎｔＥｘｔｒａｃｔａｎｔｓ￥ＹｕａｎＳｈｅｎｇｇａｎｇｅｔａｌ．（ＣｏｍｐｕｔｅｒＣｈｅｍｉｓｔｒｙＬａｂｏｒａｔｏｒｙ，ＣｈｉｎｅｓｅＡｃａ...     

单片机实现的压电式加速度计灵敏度的标定

单片机实现的压电式加速度计灵敏度的标定刘桂秋，刘冠军ＴｈｅＳｅｎｓｃｔｉｖｉｔｙＣａｌｉｂｒａｔｉｏｎｏｆｔｈｅＰｉｅｚｏｅｌｅｃｔｒｉｃＡｃｃｅｌｅｒｏｍｅｔｅｒＳｅｎｓｉｔｉｖｉｔｙｂｙＵｓｉｎｇｔｈｅＳｉｎｇｌｅ—ＣｈｉｐＣｏｍｐｕｔｅｒ￥Ｌｉ...     

第三届全球华人智能控制与智能自动化大会征文通知

征文范围ＴｅｃｈｎｉｃａｌＡｒｅａｓｏｆＰａｐｅｒｓ·智能系统与专家系统ＩｎｔｅｌｌｉｇｅｎｃｅＳｙｓｔｅｍｓａｎｄＥｘｐｅｒｔＳｙｓｔｅｍｓ·智能控制ＩｎｔｅｌｌｉｇｅｎｔＣｏｎｔｒｏｌ·神经网络及其应用ＮｅｕｒａｌＮｅｔｗｏｒｋｓａｎｄＡｐｐｌｉｃａｔｉｏｎｓ·模糊系统与模糊控制ＦｕｚｚｙＳｙｓｔｅｍａｎｄＦｕｚｚｙＣｏｎｔｒｏｌ·机器人学与机器人控制ＲｏｂｏｔｉｃｓａｎｄＲｏｂｏｔＣｏｎｔｒｏｌ·大系统ＬａｒｇｅＳｃａｌｅＳｙｓｔｅｍｓ·调度、规划、管理与决策系统Ｓｃｈｅｄｕｌｅ,Ｐｌａｎ…     

The conversion of a dynamic B-spline curve into piecewise polynomials in power form

The evaluation of points and the computations of inflection points or cusps on a curve are often necessary in CAGD applications. When a curve is represented in a B-spline form, such computations can be made easier once it is transformed into a set of piecewise polynomial curves in power form. The usual practice of the transformation of a B-spline curve into a set of piecewise polynomial curves in power form is done either by a knot refinement followed by basis conversions, or by applying a Taylor expansion on each knot span of a B-spline curve.Presented in this paper is a new algorithm to convert a B-spline curve into a set of piecewise polynomial curves in power form. Experiment shows that the proposed algorithm significantly outperforms the conventional approach when one or more control points of a B-spline curve are continuously moving.     

Reinterpretable Imager: Towards Variable Post‐Capture Space,Angle and Time Resolution in Photography

We describe a novel multiplexing approach to achieve tradeoffs in space, angle and time resolution in photography. We explore the problem of mapping useful subsets of time‐varying 4D lightfields in a single snapshot. Our design is based on using a dynamic mask in the aperture and a static mask close to the sensor. The key idea is to exploit scene‐specific redundancy along spatial, angular and temporal dimensions and to provide a programmable or variable resolution tradeoff among these dimensions. This allows a user to reinterpret the single captured photo as either a high spatial resolution image, a refocusable image stack or a video for different parts of the scene in post‐processing. A lightfield camera or a video camera forces a‐priori choice in space‐angle‐time resolution. We demonstrate a single prototype which provides flexible post‐capture abilities not possible using either a single‐shot lightfield camera or a multi‐frame video camera. We show several novel results including digital refocusing on objects moving in depth and capturing multiple facial expressions in a single photo.     

Pulse stream VLSI neural networks

EPSILON, a large, working, VLSI device, demonstrates pulse stream methods in the wider context of analog neural networks. EPSILON uses dynamic weight storage techniques, but a nonvolatile alternative is desirable. To that end, we have developed an amorphous silicon memory, which we present in experiments incorporating the device in a modest pulse stream neural chip. We have also developed a target-based training algorithm, which we demonstrate in a prototype learning device using a realistic problem. Finally, we explore system-level problems in experiments with a second version of EPSILON in a small, autonomous robot     

Fermion confinement induced by geometry

We consider a five-dimensional model in which fermions are confined in a hypersurface due to an interaction with a purely geometric field. Inspired by the Rubakov-Shaposhnikov field-theoretical model, in which massless fermions can be localized in a domain wall through the interaction of a scalar field, we show that particle confinement may also take place if we endow the five-dimensional bulk with a Weyl integrable geometric structure, or if we assume the existence of a torsion field acting in the bulk. In this picture, the kind of interaction considered in the Rubakov-Shaposhnikov model is replaced by an interaction of fermions with a geometric field, namely a Weyl scalar field or a torsion field. We show that in both cases the confinement is independent of the energy and mass of the fermionic particle. We generalize these results to the case in which the bulk is an arbitrary n-dimensional curved space.     

Visual displays: the highlighting paradox

Office computer users view well over a billion displays in a given year. The savings of only a fraction of a second in the time it takes users to process each display can potentially lead to enormous time and cost savings. In recent research investigators have shown that on average subjects are quicker to find a target option in a highlighted display than in a display without highlighting. Paradoxically, in related research other investigators have shown that subjects are slower to find a target in a highlighted display than in a display without highlighting. In an attempt to resolve this paradox, an additional set of experiments was performed. Results from these experiments suggest that in order to determine whether highlighting will be of benefit, one must know the type of highlighting, the level of highlighting validity, and the probability that subjects attend first to the highlighted options.     

Motion of a rigid cylinder between parallel plates in stokes flow : Part 1: Motion in a quiescent fluid and sedimentation

A general numerical scheme for solution of two-dimensional Stokes equations in a multiconnected domain of arbitrary shape [1, 2] is applied to the motion of a rigid circular cylinder between plane parallel boundaries. Numerically generated boundary-conforming coordinates are used to transform the flow domain into a domain with rectilinear boundaries. The transformed Stokes equations in vorticity-stream function form are then solved on a uniform grid using an iterative algorithm. In Part I coefficients of the resistance matrix representing the forces and torque on the cylinder due to its translational motion parallel or perpendicular to the boundaries or due to rotation about its axis are calculated. The solutions are obtained for a wide range of particle radii and positions across the channel. It is found that the force on a particle translating parallel to the boundaries without rotation exhibits a minimum at a position between the channel centerline and the wall and a local maximum on the centerline.

The resistance matrix is utilized to calculate translational and angular velocities of a free particle settling under gravity in a vertical channel. It is found that the translational velocity has a maximum at some lateral position and a minimum on the centerline; the particle angular velocity is opposite in sign to that of a particle rolling along the nearer channel wall except when the gap between the particle and the wall is very small. These results are compared with existing analytical solutions for a small cylindrical particle situated on the channel centerline, and with solutions of related 3-D problems for a spherical particle in a circular tube and in a place channel. It is shown that the behavior of cylindrical and spherical particles in a channel in many cases is qualitatively different. This is attributed to different flow patterns in these two cases. The motion of a spherical particle in a circular tube has qualitative and quantitative features similar to those for a cylindrical particle in a plane channel.     

A simulation-based heuristic algorithm for disposition of direction finders

A direction finder is a military weapon that is used to find locations of targets that emit radio frequencies. Multiple direction finders are used in a direction finder system for finding locations of targets in an area of interest. We present a two-stage heuristic algorithm for disposing direction finders in a direction finder system for the objective of maximizing the accuracy of estimation of the location of a target that is assumed to be located in the area of interest. In the suggested heuristic algorithm, a simulation-based method is used for estimating the probability of coverage, the probability that a target is in a given region (of a given size) surrounding the estimated location of the target, and another simulation-based method and a local search method are used to determine locations of direction finders that result in the maximum probability of coverage. Performance of the suggested algorithm is evaluated through computational experiments and results show that the algorithm gives a good disposition plan in a reasonable amount of computation time.     

Low-cost telepresence for collaborative virtual environments

We present a novel low-cost method for visual communication and telepresence in a CAVEtrade-like environment, relying on 2D stereo-based video avatars. The system combines a selection of proven efficient algorithms and approximations in a unique way, resulting in a convincing stereoscopic real-time representation of a remote user acquired in a spatially immersive display. The system was designed to extend existing projection systems with acquisition capabilities requiring minimal hardware modifications and cost. The system uses infrared-based image segmentation to enable concurrent acquisition and projection in an immersive environment without a static background. The system consists of two color cameras and two additional b/w cameras used for segmentation in the near-IR spectrum. There is no need for special optics as the mask and color image are merged using image-warping based on a depth estimation. The resulting stereo image stream is compressed, streamed across a network, and displayed as a frame-sequential stereo texture on a billboard in the remote virtual environment     

A polynomial time computable metric between point sets

Measuring the similarity or distance between sets of points in a metric space is an important problem in machine learning and has also applications in other disciplines e.g. in computational geometry, philosophy of science, methods for updating or changing theories, . Recently Eiter and Mannila have proposed a new measure which is computable in polynomial time. However, it is not a distance function in the mathematical sense because it does not satisfy the trian gle inequality. We introduce a new measure which is a metric while being computable in polynomial time. We also present a variant which computes a normalised metric and a variant which can associate different weights with the points in the set. Received: 18 October 1999 / 8 January 2001     

Visiting Byzantine Agreement underlying Ad Hoc environment

The Mobile Ad Hoc Network (MANET) has become more popular because the MANET is a self-organizing, self-configuring, and an instantly deployable multi-hop wireless network that responds to application needs without any fixed infrastructure. Moreover, the MANET is fault-tolerant and reliable. A mechanism is needed in the MANET that allows a set of nodes to agree on a common value. The distributed Byzantine Agreement (BA) problem is one of the most important issues in designing a fault-tolerant system. In many cases, reaching a common agreement among fault-free nodes in coping with the influence from faulty components is crucial in a fault-tolerant system. When a common agreement is achieved, all fault-free nodes in the system can produce stable results without any influence from the faulty components. In this study, the BA problem is visited in a MANET, in which the components are subject to a malicious fault. The proposed protocol can tolerate the maximum number of allowable faulty nodes using a minimum number of message exchange rounds. Each fault-free node can reach a common agreement value for the BA problem in a MANET. The text was submitted by the authors in English.