跟踪与数据中继卫星系统在测量船上的应用前景

介绍了国际跟踪与数据中继卫星系统（TDRSS）的基本状况与发展趋势,分析了今后测量船 利用中 继卫星系统传输高速数据的应用前景,比较了测量船加装中继卫星系统的几种方案,并 对其可行性进行了评估。     

中继卫星资源调度问题研究现状与展望

随着跟踪与数据中继卫星系统(TDRSS)的发展以及中继应用需求的增加,其资源调度成为决 定系统性能的关键因素之一。分析了包括描述方法、活动与资源、约束条件等在内的中继卫星 资源调度问题基本内涵,研究了目前中继卫星资源调度的数学模型和实现算法,比较了不同 数学模型和实现算法的优缺点。针对未来卫星激光和微波链路联合组网的发展趋势,提出了 基于多终端-多节点及基于资源故障的激光/微波混合链路中继卫星资源调度的基本方法。     

基于LMS算法的TDRSS自适应多波束形成

跟踪与数据中继卫星系统（TDRSS）是转发地球站对低、中轨航天器的跟踪测控信号和中继从航天器发回地面的信息的卫星通信系统，自适应多波束形成是TDRSS中的一个关键技术。讨论了一种基于中频实数加权的LMS算法的自适应多波束形成方法，采用两路正交实信号进行实数加权，大大节约了硬件资源。理论分析及计算机仿真结果都证明了该算法的可行性及优越性。     

多波束形成技术研究

讨论了跟踪与数据中继卫星系统 (TDRSS)中关于多波束形成的算法 ,优选的有LMS自适应方式和相位调整自适应方式 ;并简单介绍了波束控制和波束形成的实现     

中继卫星系统用户终端关键技术分析

用户终端在跟踪与数据中继卫星系统(TDRSS)中具有重要作用。介绍了中继卫星系统用户终 端的分类、功能和组成,重点对用户终端采用的全数字化可编程综合基带、自动增益控制（ AGC）、相参转发和小型化等关键技术进行了总结和分析,已工程实现的用户终端功能和性能 满足系统要求。最后,提出了用户终端技术的发展趋势。     

中继终端设备的天地网关功能设计与性能测试

近年来,空间网络协议大力发展,CCSDS空间网络协议体系已成为事实上的标准。基于跟踪与数据中继卫星系统（TDRSS）地面站中低速中继终端设备进行相应改造,增加网关路由板卡,加载CCSDS空间传输协议软件,将原来的中低速中继终端设备改造成带有路由网关功能的中低速中继终端设备。在此基础上,采用两台增加路由网关功能的中低速中继终端设备以及信道模拟器搭建天地网络演示验证系统,并分别对采用TCP协议和PEP增强协议作为传输层协议的HTTP应用进行了性能分析比对,证明PEP增强协议更能适应天地网络传输。     

跟踪和数据中继卫星系统近况

目前,美国西联宇宙通讯公司、TRW 公司与 Harris 公司合作,为宇航局研制“跟踪和数据中继卫星系统”。据称,这是新的一代卫星通讯系统,将代替宇航局跟踪网目前使用的许多设备,对宇航局和商用的地球轨道卫星进行跟踪和通讯,能提高通讯能力和降低工作维修成本。     

《电讯技术》专题资料 《国外航天测控技术的新发展》题要(一)

第二代TDRSS卫星的多址波束形成分系统跟踪与数据中继卫星系统 (TDRSS)多址 (MA)返向业务提供了一条从用户平台 (卫星或另一种发射机 )发出信号 ,经同步轨道的跟踪与数据中继卫星 (TDRS)返回给用户控制中心或数据捕获站的通信路径。传统的运行方式是根据由用户请求生成的时间表向天基网用户提供多址业务。多址业务目前向用户平台提供返向链路遥测业务 ,具有实时、回放特性 ,科学数据速率为 1 0 0kbps。支持近地航天器的Ka频段测控能力鉴于S、X和Ku频段频谱连续出现且不断增加的拥塞现象以及美国国家宇航局(NASA)对航天器高数据传…     

基于TDRSS应用的远程应急信息传输系统构想

介绍了美军天基通用数据链体系的特点，结合跟踪与数据中继卫星系统（TDRSS）现状和全球远程数据链信息传输需求，分析了TDRSS远程信息传输支持能力，提出了发展基于TDRSS的天基远程应急信息传输系统构想并预测了系统应用前景，以期对未来天基信息系统的发展和应用提供参考。     

一种应用于海上浮标的卫星中继通信终端

为了实现四级海况下海上小型浮标与岸基站数据中心之间的实时通信，设计和研制了一种高速率、低延时和高可靠的S频段卫星中继通信终端。该卫星中继通信终端由S频段中继通信机、抛物面天线、伺服跟踪机构、电源变换模块、温度控制器以及耐10 m水压的天线罩体等组成。终端为直径1 m的半球体，质量小于30 kg，最大峰值功耗小于等于130 W。卫星中继通信终端利用快速捕获跟踪卫星信号技术，能在7 s内迅速捕获和跟踪卫星前向链路信号；采用自适应海况可变码率技术提高了数据传输的可靠性。四级海况下，卫星中继通信终端实现了浮标与岸站之间最大2Mb/s高速率实时数据传输，大回路数据通信误码率小于等于10-5。     

Competition in Markets and Competition for Markets

This paper builds on a distinction that is sometimes made between competition in a market and competition for a market. Competition for a market refers to the struggle to create a new market, or to erect a new standard, and it is usually associated with the process of innovation that brings new displacing technologies to market. Competition in a market is the conventional view of competition, and concentrates on the actions of incumbents and imitative entrants in well-established markets. The paper reviews some of the issues that competition for markets raises for anti-trust policy makers, and then asks whether competition for a market is a perfect substitute for competition in a market.     

Power moderates the impact of desire for exclusivity on luxury experiential consumption

This research examines the effect of desire for exclusivity on evaluations of luxury experiences and proposes a boundary condition for the effect. The scarcity effect literature suggests that consumers prefer scarce products due to limited supply because they appeal to consumers’ desire for exclusive consumption. Building on this thesis, the current research argues that luxury experiences are intrinsically scarce enough to appeal to consumers’ desire for exclusivity: Consumers with a strong desire for exclusivity will evaluate luxury experiences more favorably than those with a weak desire for exclusivity. A pilot study confirms a positive correlation between consumers’ desire for exclusivity and attitudes toward luxury experiences. Study 1 demonstrates that consumers with a strong desire for exclusivity show more favorable attitudes toward luxury experiences than those with a weak desire for exclusivity. Further, Study 2 finds that consumers’ power state (powerful vs. powerless) moderates the effect of desire for exclusivity on their affinity for luxury experiences: Only when feeling powerful do consumers with a strong desire for exclusivity evaluate luxury experience more favorably than those with a weak desire for exclusivity. However, this is not the case when consumers feel powerless.     

Exchange Market for Complex Goods: Theory and Experiments

The modern economy includes a variety of markets, and the Internet has opened opportunities for efficient on-line trading. Researchers have developed algorithms for various auctions, which have become a popular means of on-line sales. They have also designed algorithms for exchange markets, which support fast-paced trading of standardized goods. On the other hand, they have done little work on exchanges for complex nonstandard goods, such as used cars. We propose a formal model for trading complex goods, and present an exchange system that allows traders to describe desirable purchases and sales by multiple attributes; for example, a car buyer can specify a model, options, color, and other properties of a desirable vehicle. Furthermore, a trader can enter complex constraints on the acceptable items; for instance, a buyer can specify a set of desirable vehicles and their features. The system supports markets with up to 260,000 orders, and generates hundreds of trades per second.     

Advertising for New and Existing Brands: The Impact of Media Context and Type of Advertisement

The effects of advertisement and context type on the responses to advertisements for different brands of new and existing products were tested. In the first experiment (243 graduate students) a positive emotional advertisement and a non‐emotional advertisement for a well‐known and a new brand of printer were tested in a positive emotional context and a non‐emotional media context. In the second experiment (206 graduate students) positive emotional and non‐emotional advertisements for new brands of watches and healthy drinks were tested in an emotional and a non‐emotional context. The type of context moderated the responses to advertisements for the well‐known and new products: a positive emotional context led to a more positive attitude towards the advertisement and the brand and purchase intention for the well‐known brand than for the new brand. A non‐emotional context led to more positive responses for the new brand than for the well‐known brand. In general, emotional advertisements led to more positive affective reactions and non‐emotional advertisements led to more positive cognitive reactions. However, the type of advertisement did not have a moderating effect on the responses to advertising for the new or well‐known brands or different product types. The studies illustrated the relevance of media context for advertising new versus existing products.     

Perspectives on tourism management as covered by Woodside and Martin

Tourism Management is a research journal and the short title of a book. This article examines the book as a resource for tourism students, tourism researchers and those who use tourism research in decision making. Part I of the book provides a framework for organizing 26 chapters into Parts II to VI. The chapters are research papers, some with exercises that help researchers and users of research understand good decision support by research. Analysis supports the book's value for target markets, particularly in providing good ideas and reference material about using research for decision making. However, Parts II-VI do not have introductions or conclusions. Analysis, drawing on extensive experience of the authors of this article, identifies the usefulness of a revised edition having information in each part about how the chapters fit into the book's framework and their practical significance. Discussion includes having expanded exercises for most chapters. Though suggesting changes to make a new edition better, the study here strongly endorses Tourism Management, the book, for teaching applications and as a resource for researchers and users of research.     

进出口商品质量指数在进口棉花上的应用

为了评价进出口商品的综合质量水平,研究构建了进出口商品质量指数测评模型。统计历年来棉花检验检疫、通报退运、不合格货值等数据,通过对各相关指标的权重设置,选定一个基期,测算出进口棉花质量指数。再通过一个时期不间断的数据采集及分析,可以得知该时间周期内进口棉花质量水平的变化情况,并对不合格情况提出警示。研究结果可以提高检验检疫监管效能,有利于各级监管部门进行有效监管。     

Characteristics of a Logistics-Based Business Model

In companies where excellence in logistics is decisive for the outperformance of competitors and logistics has an outspoken role for the strategy of the firm, there is present what we refer to here as a “logistics-based business model.” Based on a multiple case study of three Nordic retail companies, the purpose of this article is to explore the characteristics of such a logistics-based business model. As such, this research helps to provide structure to logistics-based business models and identifies a way forward for companies for whom logistics and distribution are a major concern for the overall strategy of the firm.     

Combining GDSS and Gaming for Decision Support

Both gaming and group (decision) support systems (GDSS) are frequently used to support decision-making and policymaking in multi-actor settings. Despite the fact that there are a number of ways in which gaming and GDSS can be used in a complementary manner, there are only sporadic examples of their combined use. No systematic overview or framework exists in which GDSS are related to the functions of gaming or vice versa. In this article, we examine, why, how and for what purpose GDSS can be used to enrich and improve gaming simulation for decision support, and vice versa. In addition to a review of examples found in the literature, four games are discussed where we combined gaming and GDSS for complex decision making in a multi actor context: incodelta, a game about transportation corridors; infrastratego, a game about a liberalizing electricity market; containers a drift, a game about the planning of a container terminal, and; dubes, a game about sustainable urban renewal. Based on the literature and these four experiences, a classification is presented of (at least) four ways in which GDSS and gaming can be used in a complementary or even mutually corrective, manner: the use of GDSS for game design, for game evaluation, for game operation and the use of gaming for research, testing and training of GDSS.     

Harmonization of product information for child-care products

Abstract

This paper gives an overview of the prenormative research that has been conducted to achieve harmonization of product information for child-care products. This research supports the work of a project group of the European Committee for Standardization (CEN/TC 252/WG 6/PG 5). The project group is preparing a chapter on product information requirements for a CEN report on the safety of children's products. In the first study, the product information currently provided with child-care products was studied. In the second study, the following was drawn up: two lists of requirements, one for the legibility and one for the understandability of product information, a warning grammar, and a basic set of explicit warnings against the most frequent and severe hazards. In the third study, the effectiveness of explicit warnings for child-care products was investigated. The results of this study indicate that people perceive products with explicit warnings as more hazardous and the possible injuries in case of an accident as more severe. In a fourth study, warning symbols were designed for a number of warnings of the basic set. Future research will focus on testing the combination of warnings and symbols for child-care products for com-prehensibility in a number of European countries.     

Managing Critical Spare Parts within a Buyer–Supplier Dyad: Buyer Preferences for Ownership and Placement

Despite the criticality and expense of spare parts, many firms lack a coherent strategy for ensuring needed supply of spare parts. Moreover, scientific research regarding a comprehensive spare parts strategy is sparse in comparison with direct material. Our research identifies and tests three literature-based, theoretically anchored attributes that influence a buyer's preference for inventory ownership and inventory placement when managing the stock of a critical spare part. Our findings indicate that item specificity and item supply uncertainty are useful in predicting a buyer's preference for managing the inventory of a critical spare part. Furthermore, we find that buyers have (1) a strong preference for consignment-based inventory management approaches, (2) a bias against inventory speculation despite its use in practice and analytical models, and (3) a strong preference for inventory postponement when the level of supply uncertainty is low.