TDD系统中不准确的CSI对MISO传输的影响

在时分工(TDD)多输入单输出(MISO)系统中,发送机通过信道估计获得信道状态信息(CSI),根据信道互易性可用其计算发送波束成形(TBF)的加权向量.然而,由于信道估计和TDD的收发机时延,CSI可能会不准确.通过推导接收机误比特率(BER)与CSI的闭合表达关系,分析了不准确的CSI对接收机性能的影响.最后用数值仿真验证了性能分析的正确性.     

信息系统使用-有效使用研究述论

信息系统的使用和有效使用是两个不同的概念,信息使用不等于有效使用。本文根据国内外学者研究结果,对IS(信息系统)采纳后的行为进行了综述,基于有效使用基础上的研究将有助于用户挖掘信息系统潜能,提升组织信息化绩效和竞争优势。并根据表象理论,提出模型试图理解IS的使用-有效使用的转换过程。     

Investigating Information Systems Research in Canada

This project reports on the state of Information Systems (IS) research in Canada by analyzing research output and impact of Canadian IS scholars appearing in the form of peer‐reviewed journal articles. Specifically, we (a) measured individual productivity and impact, (b) measured institutional productivity and impact, (c) listed journals in which these works have appeared, (d) identified the most influential articles, (e) developed a ranking of IS scholarly journals from a Canadian perspective, and (f) compared the obtained journal ranking with the global IS journal rankings. Based on the findings, it was concluded that the Canadian IS discipline exhibits signs of academic maturity. Copyright © 2011 ASAC. Published by John Wiley & Sons, Ltd.     

The Effect of Information Sources on the Success of the Organizational Buying Process

The objective of this empirical study was to investigate how the use of internal and external information sources influence the success of an organization’s buying process, and how the characteristics of the buying task influence the employment of these information sources during the buying process. Quantitative data were collected by structured interviews among Finnish business organizations early in 2008. The results suggest that the employment by an organization of information provided by a supplier during the buying process has a significant but contradictory influence on the success of the buying process. Furthermore, the complexity, newness, and importance of the buying situation were found to have a significant influence on the employment of different sources of information during the various stages of buying process. Perceived risk of the buying task was found to have no significant effect on the use of different information sources.     

The Dynamics of SME Information Systems

The process by which small firms (SMEs) invest in and gain benefit from information systems (IS) is little understood. This paper analyses two alternative models of IS-based strategic change – the Focus-Dominance model (Levy et al., 2001) and stages of growth models as applied to SMEs. An analysis of the outcomes of IS strategy development undertaken for 43 SMEs maps their IS use over time. The analysis supports the Focus-Dominance model, some parts of the stages of growth model and extends the critique of the latter. Further variances are explained by the entrepreneur/owner's values and experience. One structural variable, namely, the industry sector may also explain the variances. The implications for theory and practice are discussed.     

TDD系统中非完美信道信息条件下双流波束赋形吞吐量分析

在时分双工多天线系统中,由于上行信道估计误差和上下行传输时延,上下行链路信 道的互易性并不完美;且终端也存在信道估计误差。针对包含这些因素的非完美信道信息条 件下的双流波束赋形,导出了吞吐量准确值及其下界的表达式。分析表明,当下行链路信 噪比趋于无穷大时,由终端信道估计误差导致的每一路数据流的吞吐量损失几乎不超过lb 3 bit/s·Hz-1。数值和仿真结果表明,所得吞吐量下界与准确值较为接近;且与完美 信道信息 情形相比,非完美信道信息对系统的复用增益没有影响,只会降低系统的阵列增益。     

Implications of Consumer Information Processing Research for the Design of Consumer Information Systems

The commercial success of computerized consumer information systems will depend heavily on the extent to which they help consumers make choices. A system's usefulness will be a function of both the information it contains and the capabilities it offers to process this information. These capabilities will be incorporated in the system's access “language.” This paper reviews research on how consumers process information to make choices, and discusses the implications of this research for the design of consumer information system languages. A hypothetical example is presented and contrasted briefly with available access languages.     

Information Systems Enacted Capabilities and Their Effects on SMEs' Information Systems Adoption Behavior

Studies show that information systems (IS) adoption behavior is dependent on well‐defined characteristics. However, firms must also be enabled for use and ultimately utilize IS. This study develops a model of how IS enacted capabilities of small‐ and medium‐sized enterprises (SMEs) affect IS enablement through perceived net benefits and attitude. Follow‐up interviews with chief executive officers (CEOs)/owners of SMEs indicated that IS enacted capabilities play an integral part in determining the extent to which SMEs become enabled and utilize IS. Top management IS skills and knowledge and trust in trading partners dominate the effect on perceived net benefits at the enablement stage.     

Information Systems Strategy

The paper depicts the current state of IS strategy research with the aim of identifying research needs as well as appropriate ways to study IS strategy in the future. To this end, the paper introduces the results of an extensive analysis of academic literature on IS-strategy. In addition, it sheds light on current practice as uncovered in case-study research and through in-depth interviews with IS strategy professionals. A comparison reveals that the issues prevalent in practice and the ones traditionally focused on in the academic debate on IS strategy often vary considerably. A conspicuous attempt to fill this is the so-called “Strategizing” framework put forward by Robert Galliers. This framework, which is receiving increasing attention in the current academic debate, calls for a practice turn in IS strategy research in that it treats strategy as something people or, more precisely, IS strategists do. In addition, by identifying the challenges and problems IS strategists are faced with, the framework intends to better reflect the new planning conditions which are often seen as characteristics of the information age. The framework distinguishes three general problem domains of IS strategizing: exploration, exploitation, as well as implementation and change management.     

营销沟通中信息源可信度研究

<正>在中国市场经济不断发展的今天,自由竞争给企业带来了更多的发展机会和更大的发展空间,也给消费者带来了更充裕的物质生活和更丰富的精神食粮。但同时也带来了其他的问题。如今的消费者不用再担心买不到自己所需要的产品甚至是自己所能想像到的产品,问题的关键是怎样能买到称心如意的产品。     

建立健全规范的公司治理机制是国企改革成功的关键

随着我国国企改革的不断深入,公司治理机制已成为其核心问题。现阶段我国公司治理机制尚存在诸如产权主体“缺位”、政府干预过多及资本市场发育不完善等问题。由此,加快市场化建设、股权结构分散化等成为完善我国公司治理机制的有效途径。     

Evolutionary Business Information Systems

This article reflects on existing and emerging future challenges arising in the area of “evolutionary business information systems”, a class of systems that demand an evolutionary software development process and which support secondary design of various conceptual layers. We place both existing contributions and future research opportunities in context by referring to an idealized, preliminary system architecture. Finally, we emphasize our pluralistic perspective on the research object and the resulting need for methodological flexibility in the sense of interdisciplinary configurations of research methods.     

国储库项目烘干机系统需要研究和改善的问题

通过对国家粮食储备库项目三批烘干机系统的检测和验收，发现了一些有价值而需要进一步研究、改善和探讨的，却易被忽视的问题，具体结合检测工作的实际，提出一些解决问题的方案和方法。