Effect of automatic image realignment on visuomotor coordination in simulated laparoscopic surgery

During laparoscopic surgery, the surgeon's hand-eye coordination is often disrupted by the incongruent mapping between the orientation of the endoscopic view and the actual operative field. Two experiments were conducted to examine the effect of automatic image realignment on the performance of laparoscopic surgery. The first experiment investigated how visual-motor misalignment impacted laparoscopic surgery performance. Novice subjects were randomly assigned to one of the two paired viewing conditions in a simulated laparoscopic surgery environment: 1) the endoscope was either at the center of the modeled workspace with an optical axis of 90°, or at -45° from the midline of the subjects with an optical axis 45°; 2) the endoscope was either at 0°, or at 180° from the midline of the subjects, both with an optical axis of 45°. Each group of twelve subjects performed a dynamic point-and-touch task under the assigned pair of viewing conditions, each with eight image orientations, in a repeated-measures mixed design. The second experiment examined whether the automatic realigning mechanism that was activated mid-task (such that a congruent mapping between display and control was re-established if the mapping at the beginning of the task had been misaligned) was helpful to improve performance. Twelve novice subjects performed the same task as in the first experiment in a repeated-measures design. Performance was examined under three misaligned visuomotor mappings, each followed by the realigned mapping activated by the automatic realigning mechanism. Results showed that performance was best when the endoscopic image was perfectly aligned with the actual task space (0° image orientation), but degraded progressively as a function of deviation from perfect alignment. Subjects' performance maintained a consistent pattern across 8 image orientations regardless of optical axis orientation and endoscope location. Performance was improved with the automatic realigning mechanism. It is recommended that any solution to restore the visuomotor congruency in laparoscopic surgery should first align the image with the task space. This work has implications for the design of visualization systems in laparoscopic surgery.     

An analysis of COMET and MAGIC using the standard reference model for intelligent multimedia presentation systems

We provide an overview of two multimedia generation systems developed at Columbia University, COMET and MAGIC, and analyze them using the standard reference model for intelligent multimedia presentation systems. COMET (Coordinated Multimedia Explanation Testbed) emphasizes the coordinated generation of text and 3D graphics in a military maintenance and repair documentation domain. It features support for automated determination of what information to present, assignment of information to appropriate media and generation of textual cross-references to the structure and content of generated graphics, including the automated redesign of graphics to make possible better cross-references. MAGIC (Multimedia Abstract Generation for Intensive Care) generates presentations that use temporal media, including speech and animation, to explain the status of hospital patients. It extends the media coordination approach used in COMET to include a multi-stage negotiation process that solves temporal constraints imposed by individual media generators to determine when and for how long actions should occur in each medium.     

浅谈中小规模软件项目管理中的沟通与协作

软件项目管理中的沟通与协作是影响软件生产效率和可用性的重要问题。我国在这方面的研究较多采用规范研究的方法,本文从实证研究的角度对中小规模软件项目管理中的沟通与协作做了粗浅的探讨。     

基于WLAN的多机器人信息交互与行为协调

主要描述了一个基于WLAN的多机器人信息交互网络以及基于行为的多机器人协调避障策略.简要 介绍了无线局域网技术、网络的结构、采用的通信协议、通信内容和通信部分的软件实现.接着实现了基于网络的多 机器人信息共享,并在此基础上设计了基于行为的多机器人协调避障策略.实验结果证明了上述方法的有效性.􀁱 􀁽 􀂅     

Distributed leaderless consensus algorithms for networked Euler–Lagrange systems

This article proposes and analyses distributed, leaderless, model-independent consensus algorithms for networked Euler–Lagrange systems. We propose a fundamental consensus algorithm, a consensus algorithm accounting for actuator saturation, and a consensus algorithm accounting for unavailability of measurements of generalised coordinate derivatives, for systems modelled by Euler–Lagrange equations. Due to the fact that the closed-loop interconnected Euler–Lagrange equations using these algorithms are non-autonomous, Matrosov's theorem is used for convergence analysis. It is shown that consensus is reached on the generalised coordinates and their derivatives of the networked Euler–Lagrange systems as long as the undirected communication topology is connected. Simulation results show the effectiveness of the proposed algorithms.     

城市水生态文明建设协调度评价——以马鞍山市为例

基于协同理论构建城市水生态文明建设协调度评价模型,建立包含水安全、水生态、水供用、水管理、水文化及水景观五大子系统的"五位一体"评价指标体系,利用改进模糊层次分析法计算各指标权重,并以马鞍山市为例进行了城市水生态文明建设协调度评价。结果表明,马鞍山市2009年-2013年间城市水生态文明建设协调度稳步提升,2013年协调度为0.798,处于中度协调状态。     

基于ActiveX Scripting技术的继电保护装置自定义整定计算系统研究

研究了ActiveX Scripting技术及其在继电保护装置整定计算系统中的应用,着重研究了通过脚本语言自定义整定计算原则的设计原理。本系统从根本上实现了继电保护保护装置和整定原则的自定义计算功能,具有很强的通用性、扩展性以及可移植性。     

应用流场协同理论的多纵向涡强化换热管

应用流场协同理论研发了两种多纵向涡强化换热管———不连续双斜向内肋管和交叉缩放椭圆管,分析了其强化换热的物理机制。数值模拟和实验结果表明,当Re=500-2300 时,与考虑进口段效应的圆形截面管(L D=300)相比,不连续双斜向内肋管的换热增强250%~650%,阻力增加120% 300%;交叉缩放椭圆管Nu 可提高200%~500%,沿程阻力增加100%~350%;当Re=2300~5×104 时,与圆管相比,不连续双斜向内肋管换热可增强110%~240%,阻力增加120%~240%;交叉缩放椭圆管换热可增强35%~170%,阻力增加130%~160%。两种新型强化换热管具有优良的换热性能,可广泛应用于电力、石化、建筑供热等行业。图7参10     

锡的热液配合体系的理论热力学模型

根据锡的最新热力学资料和热液锡矿化作用的地球化学特性,理论模拟了热液配合体系中,温度、pH值、氧逸度、氟和氯的浓度对锡的迁移形式、稳定性及其溶解度的控制机理,指出了锡沉淀富集的最佳途径。