首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
诉微分算子CCS(Calclus of Communi-cating Systems)是由英国爱丁堡大学计算机科学系的RobinMilner首先提出的。CCS是一个在数学上完整的理论算子系统,可以作为计算机通讯系统的基本理论模型。我们先简要说明一个CCS的内容。我们所作的工作是在理论上扩充地的CCS,使得我们的CCS更为一般化。在我们的观战看来,RobinMiber的CCS只不过是我们的CCS的一  相似文献   

2.
SIMATIC WinCC环境中C语言的应用   总被引:2,自引:0,他引:2  
论述了SIMATIC WinCC中C语言在控制系统操作界面设计中的基本特性和应用方法。并针对WinCC中Windows编程难于掌握的特点,列举了采用WinCC内标准C语言编程的实例,以实现WinCC的功能扩展。该技术改造具有很大的通用性和灵活性,可在其功能函数的扩展中作为参考,具备推广价值。  相似文献   

3.
CCM模型是一个基于Petri网的用于软件并行开发控制的模型。本文对实现该模型的CCM系统进行了讨论。CCM系统对用CCM语言描述的CCM模型进行识别,利用可达树作为分析工具对所识别的CCM模型的活性进行分析将其转换为屏幕可视的图形形式。  相似文献   

4.
三维CAD/CAM软件评测专栏CimatronCAD/CAMV9.0系统是以色列CimatronCo。的CAD/CAM/PDM产品,是较早在微机平台上实现3DCAD/CAM全功能的系统。本次提供评测的CimatronCAD/CAM/PDMV9.0fo...  相似文献   

5.
以不同剂量的CCC对马尾松苗木进行土壤施药处理以及用不同浓度的CCC、B-9和PP333对苗木进行叶面喷施试验.1000、1500ppmCCC土壤施药以及750、1000ppmCCC,1500ppm B-9和500、750ppm pp333叶喷处理对苗木地上部分生长有明显抑作用,并明显促进根部生长,并明显促进要部生长,提高根冠比。  相似文献   

6.
在CSCW系统中应用IRC   总被引:2,自引:0,他引:2  
探讨在CWCW工作系统中采用IRC的可能性及模式。首抚,简要地介绍了CSCW和IRC基本概念,然后对协同工作中人际交流模式进行了分类研究。最后,在CSCW系统中实现IRC机制进行了研究并介绍了一个简单的IRC模型实现。  相似文献   

7.
本文以工程应用为目的,分析了串行通信技术中利用最有效的错误检测手段──增加CRC冗余位对数据错误进行检测时应采取的一种方便、有效的方法──查表法,构造了利用最通用的CRC多项式(CCITT多项式和CRC-16多项式)进行CRC快速计算的一系列函数。在实际应用中,这些函数可直接调用。  相似文献   

8.
分析了注塑模CAD/CAE/CAM技术的基本内容,综述了国内外注塑模CAD/CAE/CAM技术的主要特点和研究概况,并指出了存在的问题。提出采用特征造型技术、融合人工智能技术、勾通注塑模CAD/CAE/CAM技术,并指出了进一步发展的方向。  相似文献   

9.
以OOEDB为核心的集成化CAD/CAPP/CAM 系统GS-ICCC的设计与实现   总被引:7,自引:0,他引:7  
GS-ICCC是一个以自行研制开发的面向对象工程数据库管理系统OSCAR为核心的集成化CAD/CAPP/CAM系统,它的主要特点是按照STEP标准在全局产品数据模型基础上实现CAD,CAPP,CAM的信息集成,本文围绕着这一原则介绍了GS-ICCC的系统总体结构,OSCAR功能组织,全局产品数据建模框架以系统集成的设计与实现。  相似文献   

10.
上海大众汽车覆盖件模具CAD/CAE/CAM系统   总被引:3,自引:0,他引:3  
CAD/CAE/CAM技术在现代汽车模具设计和制造中具有重要作用,本文立足于上海大众汽车有限公司对车身覆盖件模具CAD/CAE/CAM系统的需求,论述了上海大众汽车覆盖件模具CAD/CAE/CAM系统的软硬件平和系统的结构体系,本文介绍的CAD/CAE/CAM系统已在上海大众的覆盖件模具设计制造和冲压工艺规划中的开始应用,并取得若干成果。  相似文献   

11.
This study examined the covariability between interannual changes in the normalized difference vegetation index (NDVI) and actual evapotranspiration (ET). To reduce possible uncertainty in the NDVI time series, two NDVI datasets derived from Pathfinder AVHRR Land (PAL) data and the Global Inventory Monitoring and Modeling Studies (GIMMS) group were used. Analyses were conducted using data over northern Asia from 1982 to 2000. Interannual changes over 19 years in the PAL-NDVI and GIMMS-NDVI were compared with interannual changes in ET estimated from model-assimilated atmospheric data and gridded precipitation data. For both NDVI datasets, the annual maximum correlation with ET occurred in June, which is the beginning of the vegetation growing season. The PAL and GIMMS datasets showed a significant, positive correlation between interannual changes in the NDVI and ET over most of the vegetated land area in June. These results suggest that interannual changes in vegetation activity predominantly control interannual changes in ET in June. Based on analyses of interannual changes in temperature, precipitation, and the NDVI in June, the study area can be roughly divided into two regions, the warmth-dominated northernmost region and the wetness-dominated southern region, indicating that interannual changes in vegetation and the resultant interannual changes in ET are controlled by warmth and wetness in these two regions, respectively.  相似文献   

12.
The purpose of this introduction is to provide a brief overview of the articles in this special issue and also a framework for understanding, designing and evaluating strategies for co-operative learning in the workplace and in educational environments. The special edition is divided into two parts—Issue 1: Computer Supported Collaborative Learning in Formal Education, and Issue 2: Computer Supported Team and Organisational Learning in Workplaces. In general, Issue 1 focuses on collaborative learning in primary and secondary schools and in the University setting. Issue 2 is meant to focus on learning in complex and often highly stressful work situations which mostly require intensive communication in groups or teams and in each case allow for learning in the wider organisation. This introduction outlines a set of themes that can be found in the following papers and traces briefly how each paper fits within each discussion.  相似文献   

13.
探讨了使用DiffServ QoS架构的IP网络内资源管理的带宽代理BB(Bandwidth Broker)机制以及BB使用的消息机制的安全性问题,提出了两种可用于实现消息机制安全性的方案,并给出了具体实现方法的建议。  相似文献   

14.
Spatial heterogeneity in ecosystem functioning is a key component of ecological variability requiring special attention in the context of global change. A large history of human use has produced high physiognomic heterogeneity in Mediterranean ecosystems. However, the consequences for ecosystem functioning remain insufficiently understood. We analyzed spectral indicators of matter and energy fluxes in the land surface to classify the functional ecosystem heterogeneity in a Mediterranean region covering different management histories and protection types. We specifically analyzed the spatial variability in seasonal and annual patterns in the Normalized Difference Vegetation Index (NDVI), surface temperature (Ts) and albedo from five Landsat ETM images. Then we classified numerically this variability into ecosystem functional types (EFTs) and explored their seasonal dynamics in terms of photosynthetic radiation absorption and evapotranspiration. We identified eight main EFTs with ecologically relevant differences including contrasting dynamics in fPAR seasonality, great variation in incoming radiation reflection and differing evapotranspiration rates, particularly during the water-limitation period. Functional variability in natural vegetation mostly consisted in dissimilar annual rates of NDVI and albedo, whereas differences in seasonality were more evident in transformed areas. Similarly, the spatial distribution of EFTs was partly associated to protection, with two EFTs exclusive of protected areas and comparatively higher functional diversity in humanized areas. Landform effects on water availability in protected areas and human activities under different ecological settings were seemingly responsible for the large functional diversity of the region. We advocate for the explicit incorporation of multifunctional ecosystem heterogeneity in ecosystem management and monitoring designs.  相似文献   

15.
This study evaluates empirically the proposition implicit in much recent gender and CMC research that expressions of gender distinctness among teens in online environments are becoming less frequent and less traditional. Gender preferences were analyzed in linguistic features and communication styles in synchronous text messages, along with self‐presentation in user profile pictures, drawing on data from popular English‐language teen chat sites collected in 2010. Significant differences were found in speech acts, message tone, and in physical stance, dress, and social distance in profile pictures that generally conform to traditional gender stereotypes. These findings are interpreted in light of previous gender and teen CMC research, adolescent development and socialization patterns, mass media representations, and trends towards media convergence in chat platforms.  相似文献   

16.
关联规则挖掘技术研究进展*   总被引:5,自引:2,他引:3  
为帮助人们深入研究关联规则挖掘技术,总结了关联规则的分类方法、评价方法以及相关技术的最新进展,特别是对关联规则的主要算法进行了详细的介绍,并探讨未来的发展方向。该研究比较系统全面,对将来进一步深入分析关联规则挖掘技术具有指导意义。  相似文献   

17.
Manufacturing industry is going through a period of unprecedented change as a result of the developments in micro-electronic technology. This is bringing about a transformation not only in hardware, in the form of computer-aided manufacturing, but in the manner in which production is organised and controlled.It is in the latter connection that the present paper sets out to review current developments and future trends. In particular the machine readable bar-code is seen as a key element in extending computerised control to cover not only the machines, but tools, materials and parts and their movement in the development of fully integrated manufacturing systems.As the move towards automation gathers pace it is forecast that manufacturing industry will become more process industry like in form, with consequences for the way in which production is organised and controlled.Finally consideration is given to the manner in which these current developments in the field of production are giving rise to a structural alteration in industrial labour requirements in which, in the future, fewer people will be required but on highly enriched work tasks.  相似文献   

18.
《Ergonomics》2012,55(9):1317-1329
Hotness, weight, fitting problems etc., have been found to be the chief causes of the unpopularity of industrial safety helmets in tropical environments in developing countries (DC). Some selected safety helmets manufactured in industrialized countries (IC) were modified to provide extra head ventilation and to reduce weight, in order to make them more acceptable to users in hot environments. The modified helmets were subjected to ergonomics evaluation both objectively and subjectively in the laboratory (in simulated tropical conditions) as well as in the field situation. There was evidence that white helmets had some advantages in comfort, viz. reduction of hotness, compared to the other colours, e.g. red, green etc., when worn in the presence of radiant heat in the laboratory. Ventilation holes provided at the top of the shell seemed to reduce the greenhouse effect within the helmet shell which therefore felt less uncomfortable than a fully covered helmet. Even with a small reduction of weight, such as 45 g in helmets weighing about 350g, the difference in weight was perceived by the wearers. In adapting helmets made in IC for use in tropical climates, head ventilation and low weight perception are important aspects in comfort which need to be considered. In addition to low cost, a harness material suitable for sweat absorption is required. Adjustability and sizing to fit 90% of the user population also needs to be considered in the design and manufacture of safety helmets for people in DC.  相似文献   

19.
Enhanced generation of ROS has been reported in models of hypertension such as the spontaneously hypertensive rat (SHR). Impairment of kidney function has been implicated in development and progression of hypertension, and the renal medulla appears to play an important role in regulating long‐term blood pressure. A key biomarker of oxidative stress is the formation of protein carbonyls, which we set out to characterize in the SHR medulla. We identified 11 proteins that were differentially carbonylated in SHR medulla in comparison to normotensive wistars including enolase 1, catalase, carbonic anhydrase II, transferrin and members of the aldo–keto‐reductase family. This enhanced protein oxidation was not only accompanied by an increase in intracellular iron deposition, but aldo–keto‐reductase activity was also significantly less in SHR medulla than in normotensive Wistars. Oxidative stress appears selectively to target a subset of proteins in SHR kidney and modification of these proteins may in turn contribute to the renopathy associated with hypertension.  相似文献   

20.
不同的网络操作系统(NOS)在局域网内采用的底层通信协议是不一样的,但实现文件共享的高层协议基本都采用SMB协议。文章说明如何通过对局域网内所截取的用于文件传输的SMB数据包进行分析及重组,从而得到最初的传输文件。其操作环境为Windows 2000 Professional,但实现的基本原理是适用于其它NOS建立的局域网。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号