实时动态数字减影血管造影系统与心功能测量新方法探讨

本文简要介绍最新研制的实时动态数字减影血管造影系统，该系统用普通微机及数字减影图象存储处理器实现实时动态数字减影。文中对系统硬件组成、超大容量造影图象存储处理器以及系统软件功能作了简要的介绍，论述并探讨利用本系统生成心血管减影图象进行心功能测量的新方法。     

医学影像处理集成化系统的构建与实现

文章基于系统集成技术提出了以医学影像发生器、影像处理软硬件平台和现代通讯网络为三大核心的现代医学影像处理系统的基本组成及其集成结构体系,并基于这一集成结构体系实现了数字血管减影(DSA)医学影像处理系统。该系统可实现动态医学影像数据的实时采集和海量存储、实时远程传输、实时减影处理等功能。     

计算机图像处理技术在心血管造影中的应用

着眼于现有的微机图像系统,将电视摄影或录像带中图像信息经计算机处理以提高图像的质量,实现了心血管造影再现、数字减影、以及有关参数的测量,并具有实时图像再现和减影能力。     

一个数字化X光诊断系统的实现

系统通过计算机对Ｘ光机的状态进行控制,对Ｘ光机摄取的静态和动态图象进行实时的捕捉、存储,能实现Ｘ光数字点片（ＰＤＳＩ）与数字减影（ＰＤＳＡ）,并提供了大量的图象处理算法对捕捉的图象进行后期处理,简要地说明了该系统的设计和实现情况,并对其中动态减影新算法作了介绍。     

图像增强技术在DSA减影中的应用

从DSA(Digital Subtraction Angiography,数字减影血管造影)医学图像的特点出发,提出了在实现DSA减影时,减影前先进行对数变换,减影后再进行单阈值分割的解决方案来增强血管信息.该方案已用Delphi具体软件实现,图像效果符合医学诊断的要求,得到了医学专家的充分肯定.     

基于对数非线性映射的X光数字减影图象的获取与处理

采用普通减法获取的数字减影效果不太理想,ＤＡ影象的优点无法充分体现和利用,根据Ｘ光机系统成象原理,提出了运用对数预处理和非线性灰度映射方法对目前普通减影算法进行改进。与普通算法相比,这个改进算法最终获取令人满意的高清晰度和高对比度血管图象序列。     

基于图像特征配准的数字血管减影算法

数字减影血管成象(DSA)是一种在医学诊断以及介入治疗中起重要作用的技术。在临床应用中,由于能源能量的波动、设备噪声、病人移动、器官蠕动等,通常的数字减影结果常常出现伪影。伪影消除问题成为数字减影技术中的难点,也是引起关注的热点。文章提出了消除伪影的一套新的算法———基于图像局部特征消除伪影。包括建立排除模板、控制点判定准则与方法、位移向量优化、配准方法等。该方法已用VC编制成软件,并且装备数字化X-射线装置,在计算机试验及临床实验中都取得了满意的效果。     

一种新的数字血管减影的算法

数字减影成像(DSA)是一种在医学诊断以及介入治疗中起重要作用的技术。由于通常的数字减影算法效果并不理想,该文提出了一种新的减影算法———基于分段对数变换的DSA算法。该方法已用VC编制成软件,并且装备数字化X-射线装置,在计算机实验及临床实践中都取得了满意的效果。     

心血管造影图像分割方法综述

由动脉粥样硬化病变引起的血管狭窄是冠心病的最大诱因,其发病率高,致死率高,因此研究冠状动脉的狭窄程度对于冠心病的早期诊断和评估十分重要.数字减影血管造影（DSA）图像是冠心病诊断的“金标准”.医疗辅助仪器在处理DSA造影图像对狭窄程度进行评估时,首先需要对血管进行分割,才能进行后续的狭窄程度分析.血管的分割提取是进行疾病的量化描述和血管三维重建的重要前提,也是辅助医生临床诊断和治疗的重要手段.本文针对心血管的数字减影血管造影（DSA）图像进行研究,从预处理、分割方法、评价标准3个方面总结近几年国内外针对心造影图像中血管的分割方法.     

DSA导管室信息管理系统开发与实践

伴随着科技的不断进步与医疗技术的创新, 医护人员对相关的信息系统的需求也日益提高. 为了满足导管室医生、护士的临床需求, 该文开发了一套适用于导管室的信息管理系统, 并接入医院原有的HIS系统和PACS系统. 该系统基于C/S (客户端/服务器模式)结构, 采用C#开发语言和SQL Server数据库, 根据临床需求完整实现了数字减影血管造影(DSA)导管室信息管理系统的功能, 包括手术前登记功能; 手术中介入治疗、用药记录、护理评估、耗材记录、冠脉造影、影像采集功能; 手术后报告模板、手术日志、操作记录和复杂查询功能.     

Study of differential search algorithm based automatic generation control of an interconnected thermal-thermal system with governor dead-band

An attempt has been made to the effective application of a recently introduced, powerful optimization technique called differential search algorithm (DSA), for the first time to solve load frequency control (LFC) problem in power system. In this paper, initially, DSA optimized classical PI/PIDF controller is implemented to an identical two-area thermal-thermal power system and then the study is extended to two more realistic power systems which are widely used in the literature. To assess the usefulness of DSA, three enhanced competitive algorithms namely comprehensive learning particle swarm optimization (CLPSO), ensemble of mutation and crossover strategies and parameters in differential evolution (EPSDE), and success history based DE (SHADE) are studied in this paper. Moreover, the superiority of proposed DSA optimized PI/PID/PIDF controller is validated by an extensive comparative analysis with some recently published meta-heuristic algorithms such as firefly algorithm (FA), bacteria foraging optimization algorithm (BFOA), genetic algorithm (GA), craziness based particle swarm optimization (CRPSO), differential evolution (DE), teaching-learning based optimization (TLBO), particle swarm optimization (PSO), and quasi-oppositional harmony search algorithm (QOHSA). A case of robustness and sensitivity analysis has been performed for the concerned test system under parametric uncertainty and random load perturbation. Furthermore, to demonstrate the efficacy of proposed DSA, the system nonlinearities like reheater of the steam turbine and governor dead band are included in the system modeling. The extensive results presented in this article demonstrate that proposed DSA can effectively improve system dynamics and may be applied to real-time LFC problem.     

QoS-aware distributed spectrum sharing for heterogeneous wireless cognitive networks

Ubiquitous wireless networking calls for efficient dynamic spectrum allocation (DSA) among heterogeneous users with diverse transmission types and bandwidth demands. To meet user-specific quality-of-service (QoS) requirements, the power and spectrum allocated to each user should lie inside a bounded region in order to be meaningful for the intended application. Most existing DSA methods aim at enhancing the total system utility. As such, spectrum wastage may arise when the system-wise optimal allocation falls outside individual users’ desired regions for QoS provisioning. The goal of this paper is to develop QoS-aware distributed DSA schemes using game-theoretic approach. We derive DSA solutions that respect QoS and avoid naively boosting or sacrificing some users’ utilities to maximize the network spectrum utilization. Specifically, we propose two game-based DSA algorithms: one resorts to proper scaling of the transmission power according to each user’s useful utility range, and the other embeds the QoS factor into the utility function used during gaming. To evaluate DSA schemes from a practical QoS perspective, we introduce two new metrics, namely “system useful utility” and “fraction of QoS-satisfied users”. Simulations confirm that the proposed DSA techniques outperform existing QoS-blind game models in terms of the spectrum sharing efficiency in heterogeneous networks. Convergence analysis of the proposed QoS-aware DSA algorithms is also provided.     

Representing situation awareness in collaborative systems: A case study in the energy distribution domain

The concept of distributed situation awareness (DSA) is currently receiving increasing attention from the human factors community. This article investigates DSA in a collaborative real-world industrial setting by discussing the results derived from a recent naturalistic study undertaken within the UK energy distribution domain. The results describe the DSA-related information used by the networks of agents involved in the scenarios analysed, the sharing of this information between the agents and the salience of different information elements used. Thus, the structure, quality and content of each network's DSA is discussed, along with the implications for DSA theory. The findings reinforce the notion that when viewing situation awareness (SA) in collaborative systems, it is useful to focus on the coordinated behaviour of the system itself, rather than on the individual as the unit of analysis and suggest that the findings from such assessments can potentially be used to inform system, procedure and training design. SA is a critical commodity for teams working in industrial systems and systems, procedures and training programmes should be designed to facilitate efficient system SA acquisition and maintenance. This article presents approaches for describing and understanding SA during real-world collaborative tasks, the outputs from which can potentially be used to inform system, training programmes and procedure design.     

霍尼韦尔DSA在ABS项目并网中的应用

介绍霍尼韦尔分布式系统架构（DSA）在天津大沽化工临港分厂ABS项目一期、二期并网中的应用,重点阐述霍尼韦尔DSA系统的体系结构、功能特点以及数据共享等具体实现方法。     

信息系统需求分析的面向对象层次分析方法及应用

文章将面向对象分析（ＯＯＡ）,结构化分析（ＳＡ）和数据结构分析（ＤＳＡ）方法相结合,提出了一种信息系统需求分析的面向对象层次分析方法（ＯＯＨＡ）,给出了对象的属性和方法定义以及需求分析的形式化表示方法。使用ＯＯＨＡ方法进行需求分析,层次清晰,对象关系明确,容易实现问题空间到解空间的映射。     

Modified distributed snapshots algorithm for protocol stabilization

This paper assesses the use of Chandy and Lamport's distributed snapshots algorithm (DSA) for stabilizing a communication protocol, a special type of distributed system. We show that when a loss of coordination occurs during the distributed execution of the protocol, DSA is not guaranteed to terminate, and therefore it sometimes fails to obtain a global state or snapshot. We propose some modifications to DSA to solve this problem. Finally, we discuss how, in the case of a loss of coordination, the modified algorithm can be used to stabilize a communication protocol, and we assess the suitability of the global state obtained by DSA as a recovery point to be used later in a backward recovery procedure.     

VI-attached database storage

This work presents a Vl-attached database storage architecture to improve database transaction rates. More specifically, we examine how Vl-based interconnects can be used to improve I/O path performance between a database server and a storage subsystem. To facilitate the interaction between client applications and a Vl-aware storage system, we design and implement a software layer called DSA, that is layered between applications and VI. DSA takes advantage of specific VI features and deals with many of its shortcomings. We provide and evaluate one kernel-level and two user-level implementations of DSA. These implementations trade transparency and generality for performance at different degrees and, unlike research prototypes, are designed to be suitable for real-world deployment. We have also investigated many design trade offs in the storage cluster. We present detailed measurements using a commercial database management system with both microbenchmarks and industrial database workloads on a mid-size, 4 CPU, and a large, 32 CPU, database server. We also compare the effectiveness of Vl-attached storage with an iSCSI configuration, and conclude that storage protocols implemented using DSA over VI have significant performance advantages. More generally, our results show that Vl-based interconnects and user-level communication can improve all aspects of the I/O path between the database system and the storage back-end. We also find that to make effective use of VI in I/O intensive environments, we need to provide substantial additional functionality than what is currently provided by VI. Finally, new storage APIs that help minimize kernel involvement in the I/O path are needed to fully exploit the benefits of Vl-based communication.     

Representing situation awareness in collaborative systems: a case study in the energy distribution domain

The concept of distributed situation awareness (DSA) is currently receiving increasing attention from the human factors community. This article investigates DSA in a collaborative real-world industrial setting by discussing the results derived from a recent naturalistic study undertaken within the UK energy distribution domain. The results describe the DSA-related information used by the networks of agents involved in the scenarios analysed, the sharing of this information between the agents and the salience of different information elements used. Thus, the structure, quality and content of each network's DSA is discussed, along with the implications for DSA theory. The findings reinforce the notion that when viewing situation awareness (SA) in collaborative systems, it is useful to focus on the coordinated behaviour of the system itself, rather than on the individual as the unit of analysis and suggest that the findings from such assessments can potentially be used to inform system, procedure and training design. SA is a critical commodity for teams working in industrial systems and systems, procedures and training programmes should be designed to facilitate efficient system SA acquisition and maintenance. This article presents approaches for describing and understanding SA during real-world collaborative tasks, the outputs from which can potentially be used to inform system, training programmes and procedure design.     

Distributed Shared Arrays: An Integration of Message Passing and Multithreading on SMP Clusters

This paper presents a Distributed Shared Array runtime system to support Java-compliant multithreaded programming on clusters of symmetric multiprocessors (SMPs). As a hybrid of message passing and shared address space programming models, the DSA programming model allows programmers to explicitly control data distribution so as to take advantage of the deep memory hierarchy, while relieving them from error-prone orchestration of communication and synchronization at run-time. The DSA system is developed as an integral component of mobility support middleware for grid computing so that DSA-based virtual machines can be reconfigured to adapt to the varying resource supplies or demand over the course of a computation. The DSA runtime system also features a directory-based cache coherence protocol in support of replication of user-defined sharing granularity and a communication proxy mechanism for reducing network contention. We demonstrate the programmability of the model in a number of parallel applications and evaluate its performance on a cluster of SMP servers, in particular, the impact of the coherence granularity.