有线网络行业的性质及发展路径探讨

首先分析了有线网络行业的性质,认为有线电视收看服务具有准公共产品的性质,有线网络行业属于城市公用事业。讨论了有线网络行业从事业单位到企业、从垄断到竞争的两次制度变迁,认为市场竞争条件下我国有线网络行业应做如下路径选择：保持地方性、突出专业化、区域规模化、公益性服务和市场化运营相结合。     

浅谈信源编码系统的拓扑

随着信息化的发展,网络融合在国际范围内已成为趋势。我国的网络融合（“三网融合”或称“三网合一”）主要是指国内电信网、计算机网、有线电视网的互联互通。对于现已存在的电信网、计算机网、有线电视网等各种业务基础网,基于其历史原因及竞争需要．可能会长期共存和竞争。从经济学的角度讲,互联互通是成本最低、收效最快的一种双赢博弈。信号源作为有线电视网的一种垄断性资源,随着网络融合的不断发展。     

有线网络行业的行业性质及发展路径探讨

本文认为有线电视收看服务具有准公共产品的性质,有线网络行业属于城市公用事业。讨论了有线网络行业从事业单位到企业、从垄断到竞争的两次制度变迁。认为市场竞争条件下我国有线网络行业应做如下路径选择：保持地方性、突出专业化、区域规模化、公益性服务和市场化运营相结合。     

用户驻地网的市场机制设计

本研究认为．处于固定网络边缘的用户驻地网络才具有自然垄断性,并从用户驻地网的市场机制设计人手．就如何在固定网络业务市场中引入竞争问题,进行了双向拍卖机制分析以及如何导入该机制的研究。首先,本考察了双向拍卖市场机制的均衡稳定性、收敛速度以及组织边界等问题。其次,探讨了固定网络局部存在的自然垄断性问题。再次,剖析了关于用户驻地网络开放与否的两种认识误区．     

有线传输的技术特点和发展方向分析

有线传输和无线传输是两种重要的信息传输方式.在移动互联网飞速发展的今天,有线传输仍然具有不可动摇的地位.本文对有线传输现有的技术特点进行分析,并在此基础上分析了有线传输的发展现状以及未来的发展方向,为相关人员提供一定的参考.     

卫星广播电视技术综述

现在电视信号主流传输方式有三个:有线传输、无线传输和卫星传输。这三种传输方式已经被人们所熟知,在这三种传输方式当中,卫星广播电视是覆盖面积最大,跨地域最广,最为大家所认可的传输形式。与其他传输方式相比,卫星广播电视具有技术最先进、数字化简单、在资金方面费用最少等特点。所以,数字高清晰度电视在国际上首先推广卫星广播电视和有限电视这两方面。     

IP化数字有线前端系统优势及保障措施

传统的数字有线前端系统都是采用技术相对稳定的ASI传输方式,经过10多年的应用和改善,这种技术架构的有线前端系统已趋于完善,但随着数字电视内容的不断增多和新兴业务的发展,传统ASI传输方式的有线前端系统在功能扩展方面存在某些局限性,如系统结构复杂、信号调度不灵活、扩容困难等.因此基于IP传输方式的有线前端系统在美、英、韩、印度等多国开始投入使用,目前相关技术和配套产品也已经非常成熟,我国近年来也开始出现大量IP模式的有线前端系统,这是最终实现三网融合不可跨越的过渡方案.     

有线电视双向网络建设、改造方案对比与选择

整个行业面临的是立体竞争:后有追兵——直播卫星、地面数字广播,前有堵截——IPTV、手机电视。电信运营商的IPTV业务争夺有线电视网络的高、中端用户,卫星直播和地面数字电视业务争夺有线电视网络的低、中端用户。如果维持现状、不思进取,有线电视网络就必然逐步衰落甚至被取而代之。网络改造的目的是提升网络价值、提高竞争力、提高服务质量、提高收入。改造网络的另一目的是为了应对日益激烈甚至是残酷的竞争:避免用户流失、提升多业务、全业务服务能力,从而提高网络服务的社会和经济效益。     

温室环境监控系统通信技术综述

本文分有线及无线传输方式对温室环境监控系统中的信息传输技术进行综述。有线传输方式包括RS-485总线及CAN总线,无线传输方式包括ZigBee、蓝牙、WIFI、GSM/GPRS技术等。此外,对各种传输技术的优缺点进行比较,提出了温室环境通信技术的发展方向,认为无线传输方式特别是无线WIFI将会是未来的发展重点。     

TD-SCDMA回传Wi-Fi的系统应用与优化

TDFi可以弥补有线传输的局限性,其灵活布网的模式,可以适应不同无线或移动场景需求。TD-SCDMA回传Wi-Fi系统也称TDFi,主要是解决传统WLAN网络在移动性场景应用存在的不足。传统WLAN网络需要采用有线传输方式,在移动性场景中,如公交车场景下如果想要提供Wi-Fi信号     

Progress in electrophotography in Western Europe

A review is given of the progress in electrophotographic science and technology in Western Europe during the years 1967 to early 1971. University research work is mainly directed towards two areas: 1) the electrical and physical properties of photoconductors, such as selenium, chalcogenides, oxides, and organic materials; and 2) the sensitization of these photoconductors. Industrial research teams report on the preparation of electrophotographic layers on development and on image evaluation. A bibliography including scientific papers and patents published on this subject during said period completes this review.     

智能通信在楼宇自控系统中的应用

随着计算机技术、控制技术、通信技术及信息技术的飞速发展,人们对生活、办公环境安全性、舒适性的要求日渐增长,智能建筑应运而生。楼宇自动化控制系统是智能建筑的一个重要组成部分。通过结合具体的智能楼宇控制工程项目,在介绍系统概况的基础上,给出了系统的总体设计方案及子系统的监控方案,具有一定的实用价值。     

Advances in millimeter-wave subsystems in Japan

The authors describe the development trends and results of millimeter-wave systems in Japan in such fields as communication, radar, and measurement systems. The applications included are the W-40G waveguide transmission communication system, an automobile traffic control system using the 60-GHz band, a collision avoidance radar system for an automobile, a plasma electron density measuring system, and satellite communication. The authors describe the development of devices such as high-power FET amplifiers, traveling wave tube amplifiers (TWTAs), IMPATT amplifiers, low-noise amplifiers, and monolithic microwave integrated circuit (MMIC) devices used in constructing the millimeter-wave systems     

中国带电清洗技术的突破

一、电路故障的成因 通常,由于空气的污染和设备所处的环境及管理条件不同,空气中的灰尘、油污、酸碱及其气体、盐分、潮气、炭渍、金属尘埃、各种机械杂质等污染物质,不可避免地吸附在电路表面及其它部位,加之静电累积和在电场力的作用下,污秽的累积不断加重和变得牢固,各种污秽牢牢附着在线路表面,深层及各部位。灰尘、油污、酸碱及其气体、盐分、潮气、炭渍、金属尘埃、各种     

Telecommunications in Malaysia: diversity in adversity

The telecommunications industry in Malaysia has experienced a tremendous transformation in just over a decade. The government-owned Jabatan Talikom, which hitherto operated the network, was incorporated in 1987 and subsequently privatized a few years later, with a majority share holding by the government. The regulatory aspects were spun off under the slim looking JTM. This marked the beginning of liberalization, and many new players entered the fray. This article reviews the telecommunications infrastructure and services available in Malaysia and visits some of the telcos offering these services. Some pertinent issues affecting the industry are also discussed     

Losses in small-radius bends in single-mode fibres

Refractive index profiles and mode field radii determine small-radius bending losses in single-mode fibres. Losses in six different types of fibres were measured in bends with radii ranging from 1.25 to 8 mm. The results show that a refractive index depression in the core centre reduces the bending-loss sensitivity.<>     

Rearrangements in cell populations in malignant growth

It is emphasized that one of signs of malignant growth is heterogeneity of cell population which arises at the earliest pretumour stages and determines the character of tumour progression. At the same time by means of selective influences on population of malignant cells it is possible to change their quantitative correlation and to obtain rearrangement of the normal cell interrelations. Initiation of the tumour, its progression and regression are considered on the basis of the population-cell rearrangement, typical of each of them separately. The concept of the unity of the carcinogenesis and anticarcinogenesis processes is also formulated.     

General Trend in Electrical Communications in Japan

Systems are currently being designed for higher reliability and greater economy. Larger transmission capacity is required to meet a rapid increase in recent communication demands instigated by the introduction of video and information communications facilities. More flexibility, to deal with the variety of communication modes to come, and smaller hardware dimensions, to overcome situations caused by the high population density, seem to be particularly sought in the communication technology of Japan. Research and development concentrate on these objectives. The following is an explanation of the present state of the art and general trends in this country.     

Progress in display-device development in Western Europe

A review of the basic research and industrial development of display devices in Western Europe during the years 1968 to early 1973 will be given. The display types considered are: 1) active displays such as cathode ray tubes, light-emitting diodes, electroluminescence cells, and gas discharge devices, and 2) passive displays such as laser displays, light valves, and ferroelectric and liquid-crystal devices.