大規模多元接続ネットワークのためのグラフ構造に基づくランダムアクセス方式

電気通信大学201

Towards new technology : computerization for maritime education and training at the Philippine Merchant Marine Academy

The key to success of any maritime education and training programs in achieving its goals and objectives will depend upon how well various new technology is being used toward the learning process by every educator. This dissertation looks at the use of new technology in maritime education and training such as computer aided learning, to provide basic knowledge and understanding of the functions of the different parameters of computer systems. The paper describes the potential use of computer technology in MET, particularly in a developing country. Some models of computer aided learning (CAL) and computer based training (CBT) are also examined. It describes the overall process of learning and the use of different high-technology instructional materials. The dissertation also considers the integration of computers to new curricula and discusses the implementation of the same. The different models of CAL are studied to improve the system of teaching in the maritime field. In addition, the dissertation evaluates two leading maritime training software programs currently available in the market. Other maritime software programs are also investigated and discussed. In conclusion, proposals and recommendations are made to improve the training facilities and the teaching method at Philippine Merchant Marine Academy (PMMA) for every student in the field of maritime education and training. The use of computer technology at PMMA for education and training is a method of ensuring that the skills and ability of the trainees are vastly improved

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids

Developments of 5G Technology

This technology is the future of current LTE technology which would be a boost to the future of wireless and computer networks, as the speeds would be way higher than the current LTE networks, which will push the technology to a new level. This technology will make the radio channels to support data access speeds up to 10 Gb/s which will turn the bandwidth radio channels as WiFi. Comparing it with other LTE technology\u27s it has high speed and capacity, support interactive multimedia, voice, internet and its data rate is 1 Gbps which makes it faster than other LTE’s . This is much more effective than other technology’s due to its advanced billing interfaces. This paper provides detail explanation of 5G technology, its architecture, challenges, advantages and disadvantages, issues and ends with future of 5G technology

Multimedia performance evaluation of ethernet and token ring media access protocols: a network comparison

This paper and accompanying project examines which type of time-division multiplexing media access protocol, the Carrier Sense Multiple Access (CSMA) of Ethernet or the token passing of token ring, is best able to fulfill the stringent isochronous performance demands required of today's resource-hungry multimedia networks, specifically the requirements of high throughput, low latency and jitter, and minimal error rates. Using performance bounds accepted by other researchers as sufficient to ensure quality isochronous transmission, that of (1) the throughput rate being equal to or less than the playback rate; (2) the latency in transmitting each packet ranging from 20 to 400 milliseconds and the variance or jitter being less than 80 milliseconds; and (3) the rate of lost packets ranging from 0.01--1.001, this paper approaches a solution first from the theoretical and then integrates into the final conclusion an analytical, C++ software evaluation test component that models network performance under optimum conditions. The immediate benefit of the entire study is the identification of one media access protocol, Ethernet or Token Ring, over its counterpart as being superior for isochronous applications as defined by the above performance requirements, and the long-term consequence of this identification will be facilitating for future network designers, including those of digital libraries, the selection of the best network architecture for their multimedia environments

A study of topologies and protocols for fiber optic local area network

The emergence of new applications requiring high data traffic necessitates the development of high speed local area networks. Optical fiber is selected as the transmission medium due to its inherent advantages over other possible media and the dual optical bus architecture is shown to be the most suitable topology. Asynchronous access protocols, including token, random, hybrid random/token, and virtual token schemes, are developed and analyzed. Exact expressions for insertion delay and utilization at light and heavy load are derived, and intermediate load behavior is investigated by simulation. A new tokenless adaptive scheme whose control depends only on the detection of activity on the channel is shown to outperform round-robin schemes under uneven loads and multipacket traffic and to perform optimally at light load. An approximate solution to the queueing delay for an oscillating polling scheme under chaining is obtained and results are compared with simulation. Solutions to the problem of building systems with a large number of stations are presented, including maximization of the number of optical couplers, and the use of passive star/bus topologies, bridges and gateways

Design and development of a new large-scale metrology system: MScMS (Mobile Spatial coordinate Measuring System)

This thesis arises from the research activity developed at the Industrial Metrology and Quality Engineering Laboratory of DISPEA - Politecnico di Torino, on a new system prototype for dimensional measurement, called Mobile Spatial coordinate Measuring System (MScMS). MScMS determines dimensional features of large-size objects and has been designed to overcome some limits shown by other widespread measuring sets used nowadays, like Coordinate Measuring Machines (CMMs), theodolites/tacheometers, photogrammetry equipments, GPS based systems, Laser Trackers. Basing on a distributed sensor networks structure, MScMS can accomplish rapid dimensional measurements, in a wide range of indoor operating environments. It consists of distributed wireless devices, communicating with each other through radiofrequency (RF) and ultrasound (US) transceivers. This frame makes the system easy to handle and to move, and gives the possibility of placing its components freely around the workpiece. The wireless devices − known as "Crickets" − are developed by the Massachusetts Institute of Technology (MIT). Being quite small, light and potentially cheap (if mass produced), they fit to obtain a wide range of different network configurations. These features make the new system suitable for particular types of measurement, which can not be carried out, for example, by conventional CMMs. Typical is the case of large-size objects which are unable to be transferred to the measuring system area (because of their dimensions or other logistical constraints) and thus require the measuring system to be moved to them. In the dissertation the system is described exhaustively and characterized through practical experiments. Then, the system is compared to classical CMMs and the indoor-GPS (iGPS), an innovative laser based system for large-scale metrology. Finally, future directions of this research are give

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion