中国农村通信的今昔与未来

中国农村通信技术经历了从人工、机电到程控的逐步而漫长的发展过程,经营体制上也经历了一系列变迁,并长期保持国营、地方国营和集体所有制等多种体制并存的局面。目前虽然农村通信已经取得了长足进步,但广大的中西部,尤其是偏远地区、山区和海岛等电信发展水平还很低,并面临各种困难。建议建立普遍服务基金,建设农村综合信息传播网,采取无线和卫星等技术,促进农村通信的快速发展。     

Wireless Technologies in Healthcare: Selected Papers from IEEE PIMRC 2011

The use of wireless technologies for medical device communication, health monitoring (at hospitals or homes) and mobile healthcare information delivery (i.e. m-Health) is one of the most rapidly growing areas in health-IT research today. The papers which appear in this special issue have been carefully selected from the best IEEE PIMRC 2011 conference. They are highlighting various challenging issues in using wireless technology for healthcare applications such as PHY & MAC innovations for wearable and implantable medical sensors, optical communication and location systems in hospital environments and interference mitigation issues.     

Tighter controls for busier systems [power systems]

A variety of new technologies are becoming available that will help utilities maintain power system reliability while handling the larger volume of transactions. For example, power electronic systems can provide unprecedented control over electricity flow on transmission networks, preventing or containing cascading disturbances. In addition, new sensor technology, faster communications between control centers, and advanced software tools can enable utilities to monitor system conditions in real time, letting them respond more quickly to disturbances and minimize their impact. Over the next decade, these technologies will facilitate increased power transfers through power delivery systems that are presently constrained, providing power at lower cost to a greater number of customers. It is a question of how to optimize power flow through an entire network by integrating multiple technologies and coordinating control over wide areas. Such integration and coordination will be necessary for deregulation to proceed smoothly toward its twin goals: reducing electricity costs to US consumers, while maintaining the high levels of reliability they have come to expect. The authors discuss the following technologies to help achieve these goals including: flexible AC transmission systems (FACTS), the next generation of FACTS controllers, hierarchical control of FACTS, on-line power systems analysis, control centre communications, and wide area measurement system     

Telemedicine diffusion in a developing country: the case of India (March 2004).

Telemedicine (health-care delivery where physicians examine distant patients using telecommunications technologies) has been heralded as one of several possible solutions to some of the medical dilemmas that face many developing countries. In this study, we examine the current state of telemedicine in a developing country, India. Telemedicine has brought a plethora of benefits to the populace of India, especially those living in rural and remote areas (constituting about 70% of India's population). We discuss three Indian telemedicine implementation cases, consolidate lessons learned from the cases, and culminate with potential researchable critical success factors that account for the growth and modest successes of telemedicine in India.     

Analysis of information and communication needs in rural primary health care in developing countries.

This article presents three studies dealing with information and communication needs in rural primary health care from Peru and Nicaragua. Results show that primary health-care systems in rural areas of developing countries are very inefficient. Among the main reasons we found factors related to communication infrastructure, information sharing, and continuous training of health professionals. We conclude that telemedicine systems can improve this situation, but the lack of infrastructures, low income levels, and other conditions, impose strong limits to the introduction of new technologies. The main conclusion is that differences in needs and conditions between developing countries and industrialized ones force to use different solutions and approaches. This article presents some proposals on technology requirements and how to deal with the use of telemedicine in rural areas of developing countries. These proposals can be useful to all kind of actors (national public administrations, multilateral institutions, industry, academy, civil society, etc.) in order to promote really relevant and sustainable proposals in telemedicine for rural regions of developing countries.     

Unlicensed cognitive sharing of TV spectrum: the controversy at the Federal Communications Commission

As societies become increasingly mobile and more dependent on information technologies, their radio spectrum also needs change. The basic spectrum management structure in all countries was developed over a long period, and much of the basic framework has remained stable for decades. The FCC is interested in making more spectrum available to unlicensed devices because of the explosive growth of IEEE 802.11/Wi-Fi unlicensed wireless LAN technology, and because the FCC recognizes that there is a great deal of "white space" that could be exploited by unlicensed devices. The FCC proposal selected the TV bands as an initial home for cognitive radio based on several factors. First, the frequencies used for TV can give greater range in rural areas than the microwave frequencies used for Wi-Fi, and can also give better building penetration than Wi-Fi in all areas. Second, TV broadcast systems usually use high antennas, and the intended receivers need greater than 10 dB signal-to-noise ratio (SNR) to function. A variety of controversial issues have emerged from public comments. One concern is that the confusion resulting from the proposal might discourage purchase of new digital televisions and hence delay the transition from analog to digital televisions. This would also delay the transfer of some current TV spectrum to new mobile uses, including public safety.     

Hybrid wireless-broadband over power lines: a promising broadband solution in rural areas

In rural areas, due to the low population density and the poor familiarization with new technologies, new projects related to broadband access are less profitable. In this article a hybrid wirelessbroadband over power lines network, suitable for rural and remote areas is presented, offering smart grid applications and broadband access along a 107 km medium voltage power grid in Larissa, a rural area in central Greece. This hybrid solution exploits the ubiquitous presence of the power grid along with the adaptability and accessibility of wireless technology. Through the design and implementation of this hybrid network many aspects of BPL technology were successfully dealt with demonstrating that, in addition to enhancing the power grid performance, W-BPL technology may be considered as an alternative broadband solution in rural and/or sparsely populated areas.     

Guest editorial. Introduction to the special section: 4G Health--the long-term evolution of m-Health

In the last decade, the seminal term and concept of "m-health" were first defined and introduced in this transactions as "mobile computing, medical sensor, and communications technologies for healthcare." Since that special section, the m-health concept has become one of the key technological domains that reflected the key advances in remote healthcare and e-health systems. The m-health is currently bringing together major academic research and industry disciplines worldwide to achieve innovative solutions in the areas of healthcare delivery and technology sectors. From the wireless communications perspective, the current decade is expected to bring the introduction of new wireless standards and network systems with true mobile broadband and fast internet access healthcare services. These will be developed around what is currently called the fourth-generation (4G) mobile communication systems. In this editorial paper, we will introduce the new and novel concept of 4G health that represents the long-term evolution of m-health since the introduction of the concept in 2004. The special section also presents a snapshot of the recent advances in these areas and addresses some of the challenges and future implementation issues from the evolved m-health perspective. It will also present some of the concepts that can go beyond the traditional "m-health ecosystem" of the existing systems. The contributions presented in this special section represent some of these developments and illustrate the multidisciplinary nature of this important and emerging healthcare delivery concept.     

Crossing the digital divide: cost-effective broadband wireless access for rural and remote areas

The use of wireless, DSL, and cable for broadband access has become increasingly prevalent in metropolitan areas. While these technologies are being successfully utilized in terms of both service quality and economics in densely populated areas, there are still vast geographic regions where broadband services are either prohibitively expensive or simply unavailable at any price. The article examines several alternatives for using 2.4 GHz 802.11b (WiFi) technology to provide fixed broadband access in rural areas consisting of towns, smaller remote communities, clusters of subscribers separated by large intercluster distances, as well as widely scattered users. Our approach is to model a network based on realistic demographics, equipment and operations costs, service revenues, and customer demand and usage, and calculate the lifecycle economics in terms of capital investment and profitability. We consider the cost benefits of several emerging technologies and architectures, including high gain antennas, dynamically steerable beamforming antennas, and multihop routing. Our results show that cost-effective affordable high-speed wireless Internet access can be provided in rural and remote areas using nontraditional and innovative approaches, bridging the so-called digital divide.     

QoS provisioning in GEO satellite with onboard processing using predictor algorithms

Recently, IP satellite networks have attracted considerable interest as a technology to deliver high-bandwidth IP-based multimedia services to nationwide areas. In particular, IP satellite networks seem to be one of the most promising technologies for connecting users in rural areas, where a wired high-speed network (e.g., xDSL) is not foreseen to be used. However, one of the main problems arising here is to guarantee specific quality of service constraints in order to have good performance for each traffic class. Among various QoS approaches used in the Internet, recently the DiffServ technique has become the most promising solution, mainly for its scalability with respect to the IntServ approach. Moreover, in satellite communication systems, DiffServ computational capabilities are placed at the edge points, reducing the implementation complexity of the satellite onboard equipment. This article deals with the problem of QoS provisioning for packet traffic by considering some resource allocation schemes, including bandwidth allocation techniques and priority-driven onboard switching algorithms. As to the first aim, the proposed technique takes advantage of proper statistical traffic modeling to predict future bandwidth requests. This approach takes into consideration DiffServ-based traffic management to guarantee QoS priority among different users. Moreover, the satellite onboard switching problem has been addressed by considering a suitable implementation of the DiffServ policy based on a cellular neural network.     

Comparing Crystalline Silicon Solar Cells with Thin Film

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Broadcasting by satellites

As a result of recent advances in signal processing technology and standards for video compression systems there has been a dramatic increase in interest in commercial applications. This paper reviews the current broadcasting situation from a number of viewpoints relevant to the future development of the available technologies. After a review of the context, which includes alternative new broadcasting technologies as well as alternative media capable of competing with satellite, digital technology is given a wide ranging assessment with particular attention paid to the direct broadcasting to the home by satellite application currently receiving considerable attention world-wide. The possible system architectures and subsystem design features are highlighted with the European Baseline Satellite Broadcasting specification developed by the European Digital Video Broadcasting Project gaining special attention. For completeness a brief review of the digital audio broadcasting system (DAB) is also given. In addition to the applications for direct broadcasting, applications in the professional domain for distributing television signals from studios to terrestrial transmitters, satellite up-link sites or cable heads or for satellite news gathering (SNG) are examined. Features of existing commercially available hardware to support these services are described briefly.     

Technological opportunities for the delivery of health care

This paper has been designed to examine the programs and aspirations assigned to the National Center for Health Services Research and Development which has just recently been created in Washington, D. C. This Center will be supported by grants and contracts, and will endeavor to promote, support, and stimulate a national program of health-services research, development, and demonstrations. More specifically, the National Center for Health Services Research and Development will attempt to make health services available to all people and to assist all health professions in their efforts to improve their ability to assess the quality of their services. It will also investigate the comparative costs of alternative methods of providing and financing health services and experiment with architectural designs, site locations, plans, and new methods of construction. The Center will try to increase the efficiency of health services by developing new methods of training and using personnel. Applying and refining computer technology in screening techniques, automation of medical records, and selected other aspects of medical care process will be included in the program, as well as methods for accelerating the applications of new or improved techniques for the prevention, treatment, and control of diseases and other disabilities. The Center will design and initially operate experimental health-services systems in both urban and rural areas. It will make multi-disciplinary analyses of the organization and functioning of all components of the health-services system and will increase academic resources for training health-services research and for developing personnel. The Center will establish and operate a health-services data system relevant to research and development, planning, policy making, and management. Much of this paper discusses the opportunities which exist in the development of computer technology in the United States in relation to the delivery of health care.     

Distributed objects and object databases

Due to the on-going shift from centralised to decentralised computing and a general trend towards the globalisation of commercial, economic and social activities, the information systems community has been faced with strong demands to develop distributed information systems (DISs) that span wide geographical areas. Three technologies have had significant impact on the new generation of DISs — distributed object technology, object database technology and Web technology. The paper examines two of these — DOT and ODBT. Each has advantages over the other, but more importantly they complement each other, and ways of using them together are explored.     

Impact of 3G and beyond technology development and pricing on mobile data service provisioning,usage and diffusion

This study investigates the third generation mobile telecommunication systems (3G) diffusion challenges in the situation where large-scale mobile data service usage has not yet broken through. The paper first analyzes incumbent mobile operator business prospects in a large Western-European country. The results suggest that rollout of the most advanced available 3G technologies pay back through increased data service usage and revenues in the situation of declining voice revenues. In the main body of the study we discuss different pricing models and demonstrate that the flat rate pricing of data services, supplemented with certain conditions, supports the large-scale take-up of mobile data services. It boosts the usage of mobile data services and provides a competitive and sustainable business model for the operators and other market actors at the same time. Our modeling indicates furthermore, that flat rate model, combined with open access, gives better incentives to rollout high-speed mobile technologies to the rural areas, than the traffic-based charging.     

Applications of space communications technology to critical human needs: rescue, disaster relief, and remote medical assistance

The applications of space communications technology to various critical human needs are discussed. Satellite communications, telemetry, and biotelemetry have provided timely and crucial communications capabilities over remote distances. The use of satellite/beacon systems have been used for disaster relief as well as search and rescue operations. The combination of telemetry and electronic medical systems (telemedicine) have augmented existing health care delivery and have provided consultation links between remotely located health care specialists working with patients and physicians at a central location. This has been expanded into networks to respond to victims of disasters in need of critical medical assistance with the hope that with further work, telemedicine may become available to all nations through an international network.     

Evolution of Terrestrial Optical System and Core Network Architecture

Optical systems and technologies have been radically changing the telecommunication networks for past 15 years; today wavelength division multiplexing (WDM) technology, optical amplifiers, and simple optical switching elements like optical add-drop multiplexers (OADMs) are used in the backbone networks of all operators worldwide. Optical systems nowadays provide the basis for cost-effective transmission of large amounts of bandwidth over the Internet, and will enable its future growth and the spreading of new applications and services. This paper summarizes the main trends in optical networking and investigates potential future application areas. Optical system technology has become so pervasive in network design that it needs to be considered in the context of provisioning new applications and services. Therefore, the analysis is not limited to the aspects of physical transmission, but also takes into account recent developments in integrated network design as well as network control and management. The following sections describe the key functionalities of future optical network architectures, and the key findings of the theoretical analysis are supported by the results of a field trial of advanced transmission technology.     

Polymers Exhibiting Lower Critical Solution Temperatures as a Route to Thermoreversible Gelators for Healthcare

The ability to trigger changes to material properties with external stimuli, so-called “smart” behavior, has enabled novel technologies for a wide range of healthcare applications. Response to small changes in temperature is particularly attractive, where material transformations may be triggered by contact with the human body. Thermoreversible gelators are materials where warming triggers reversible phase change from low viscosity polymer solution to a gel state. These systems can be generated by the exploitation of macromolecules with lower critical solution temperatures included in their architectures. The resultant materials are attractive for topical and mucosal drug delivery, as well as for injectables. In addition, the materials are attractive for tissue engineering and 3D printing. The fundamental science underpinning these systems is described, along with progress in each class of material and their applications. Significant opportunities exist in the fundamental understanding of how polymer chemistry and nanoscience describe the performance of these systems and guide the rational design of novel systems. Furthermore, barriers to translating technologies must be addressed, for example, rigorous toxicological evaluation is rarely conducted. As such, applications remain tied to narrow fields, and advancements will be made where the existing knowledge in these areas may be applied to novel problems of science.