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arXiv 2020年

作者： Qin, Shize Klaaßen, Lena Gallersdörfer, Ulrich Stoll, Christian Zhang, Da Institute of Energy Environment and Economy Tsinghua University Beijing100084 China TUM School of Management Technical University of Munich Munich Germany TUM Software Engineering for Business Information Systems Department of Informatics Technical University of Munich Munich Germany MIT Center for Energy and Environmental Policy Research Massachusetts Institute of Technology CambridgeMA United States TUM Center for Energy Markets TUM School of Management Technical University of Munich Munich Germany MIT Joint Program on the Science and Policy of Global Change CambridgeMA02139 United States

The carbon footprint of Bitcoin has drawn wide attention, but Bitcoin’s long-term impact on the climate remains uncertain. Here we present a framework to overcome uncertainties in previous estimates and project Bitcoin’s electricity consumption and carbon footprint in the long term. If we assume Bitcoin’s market capitalization grows in line with the one of gold, we find that the annual electricity consumption of Bitcoin may increase from 50 to 400 TWh between 2020 and 2100. The future carbon footprint of Bitcoin strongly depends on the decarbonization pathway of the electricity sector. If the electricity sector achieves carbon neutrality by 2050, Bitcoin’s carbon footprint has peaked already. However, in the business-as-usual scenario, emissions sum up to 2 gigatons until 2100, an amount comparable to 6% of global emissions in 2018. Therefore, we also discuss policy instruments to reduce Bitcoin’s future carbon footprint. Copyright © 2020, The Authors. All rights reserved.

关键词： Carbon footprint

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RATIONALE FOR AN ADA software engineering ENVIRONMENT FOR NAVY MISSION CRITICAL APPLICATIONS

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NAVAL ENGINEERS JOURNAL 1984年第4期96卷 133-145页

作者： PAIGE, KK CONVERSE, RA USN LCdr. Kathleen K. Paige USN:graduated with a BA from the University of New Hampshire in 1970. She received her commission from Officer Candidate School in April 1971 and performed her first tour of duty with VFP-63 NAS Miramar. LCdr. Paige then received her MS from the Naval Post Graduate School in June 1976 and returned to San Diego to serve as Head Support Software Division at the Fleet Combat Direction System Support Activity. In May 1981 she reported to NA VSEA (PMS-408) where she served initially as Chairman of the NAVMAT Software Engineering Environment Working Group. She has been assigned as Deputy AN/UYK-43 Acquisition Manager since October 1981. LCdr. Paige was designated a fully qualified Engineering Duty Officer in December 1983. Robert A. Converse:is presently the Acquisition Manager for the Ada Language System/Navy (ALS/N) for the Naval Sea Systems Command Tactical Embedded Computer Resources Project. As such he is responsible for the definition and development of the ALS/N to be provided as a Navy standard computer programming system for Navy mission critical applications. Mr. Converse received a Bachelor of Science degree in Physics from Wheaton College Wheaton II. He spent fourteen years with the Naval Underwater Systems Center Newport Rhode Island during which time he designed and developed the Fortran compiler for the Navy Standard AN/UYK-7 computer. Also during that period he received a Master of Science degree in Computer Science from the University of Rhode Island. His thesis for that degree was entitled “Optimization Techniques for the NUSC Fortran Cross-Compiler”. Mr. Converse started his involvement with the Ada program in 1975 with the initial “Strawman” requirements review. Subsequently he was named as the Navy Ada Distinguished Reviewer and was intimately involved in the selection and refinement of the Ada language as it evolved to become ANSI/MIL-STD-1815A.

The U.S. Navy introduced the use of digital computers in mission critical applications over a quarter of a century ago. Today, virtually every system in the current and planned Navy inventory makes extensive use of computer technology. Computers embedded in mission critical Navy systems are integral to our strategic and tactical defense capabilities. Thus, the military power of the U.S. Navy is inextricably tied to the use of programmable digital computers. The computer program is the essential element that embodies the system “intelligence”. In addition, it provides the flexibility to respond to changing threats and requirements. However, this very flexibility and capability poses a host of difficulties hindering full realization of the advantages. This paper describes the lessons learned about computer program development over the past twenty five years and discusses a software engineering process that addresses these lessons. It then describes how Ada and its related Ada programming Support and Run-Time Environments foster this software engineering process to improve computer program productivity and achieve greater system reliability and adaptibility. Finally, the paper discusses how the use of Ada and its environments can enhance the interoperability and transferability of computer programs among Navy projects and significantly reduce overall life cycle costs for Navy mission critical computer programs.

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EMI - THE ENEMY WITHIN

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NAVAL ENGINEERS JOURNAL 1992年第2期104卷 69-80页

作者： BARON, NT CEBULSKI, DR Neil T. Baronis currently the team leader for the combat system topside design work for amphibious assault auxiliary mine warfare and Coast Guard ships. He sits on the IEEE SCC-28 Committee for personnel radiation hazards and is extensively involved in the EM engineering initiative at NavSea. Mr. Baron has lectured at the MIT Summer Professional Series on the subject of electromagnetic interference. While attending Marquette University he started his career with the Navy as a coop student supporting personnel radiation hazard assessments. After graduating with a BS in bio-medical engineering he took an electronics engineer position in the Systems Electromagnetic Division. Since then he has lectured on Navy training films and has developed several software packages which have pushed the state-of-the-art in EMI assessment. Mr. Baron has prepared several reports and professional papers. He has worked on several professional committees and in February of 1991 was awarded the “Young Engineer of the Year Award” which was presented by the D.C. Council of Engineering and Architectural Societies. Donald R. Cebulskiis currently the head of the Topside Design Division in the Naval Sea Systems Command Weapons and Combat System Directorate. He graduated from the University of Michigan with a bachelor's degree in 1963 and a master's degree in 1977 both in naval architecture and marine engineering. He started his career in 1964 at the Bureau of Ships and joined the Aircraft Carrier Section of the Arrangements Branch in Hull Design. During the past 25 years he has included almost every naval ship type in his ship arrangement experience and in October of 1988 he transferred to the Topside Design and Integration Branch in the System Electromagnetics Division Sea 06. Mr. Cebulski has written several papers on ship arrangements computer aided design and ship topside design. He prepared and presented lectures at the MIT Professional Series on ship topside design and has served on many ASNE committees. He is currently the

Electromagnetic interference (EMI) is one of the major contributors to mission degradation in our fleet today due to the increase in population and sensitivity of both topside and below deck electronic systems. Sensitive combat systems designed to counter intelligent and deceptive targets can be confused by the complex intra-ship EM environment. This can cause identification failure or losing "track" of a hostile or incoming missile or even engaging "friendly targets." Topside design and integration efforts have been used to reduce EMI, but this is not the total solution to the problem. A program of total ship and system EMI assessment and control must be implemented. This program must exploit electromagnetic compatibility (EMC) optimization in electronic circuit design and take advantage of and (in some cases) direct topside shapes and structures to control the propagation of desired and undesired EM energy. Positive and active control of EM design characteristics are absolutely required before optimum combat system effectiveness can be realized. This paper will describe the current topside design process, EMC improvements being made, and how the process is being integrated into, and is dependent upon, the ship design process. It will give examples of some of the major mission degrading EMI problems in the fleet today and how past problems were solved with existing EM analysis programs. It will also discuss the control of EM energy in new design through the use of techniques being developed such as ray tracing and ray casting. The paper projects where the challenges lie for future topside and EM engineering designers and describes how the equipment technology transfer process must be better integrated to meet the challenge of effective EMI control.

关键词： Signal Interference

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Empirical testing: The prototyper's evaluation mechanism

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NAVAL ENGINEERS JOURNAL 1997年第1期109卷 41-46页

作者： Hafner, AN Arnold N. Hafner Ph.D.:is founder and president of Information Systems Research (ISR). He has twenty-five years of experience in systems development and is published in the field of systems development management. He served as corporate research scientist at Systems Exploration Inc. from 1988 to 1991 program director at Computer Science Corporation from 1983 to 1988 director of operations at Republic Management Systems Corporation from 1981 to 1983 and program manager at Computer Science Corporation from 1972 to 1981. A 1962 graduate of the US. Naval Academy he holds a doctoral degree in human behavior and engineering degrees in electronics and communications. He has taught courses on information systems and systems management at most of the colleges in the San Diego area. Dr. Hafner has presented fourteen refereed research papers while publishing sixteen articles and a book A Manager's Guide to Software System Development.

Evaluating complex systems is the subject of this paper, the third in a series investigating prototyping. It provides an interesting and helpful overview of how to evaluate systems prototypes and outlines the iterative stream of developer-user interactions that is replacing older approaches to testing and evaluating new military systems, which promise to reduce the time required to develop and field future military capabilities. Changes to the acquisition process, such as those the paper sketches, will facilitate the nation's rapid transit through its current revolution in military affairs.

关键词： Systems analysis

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Multi-Coil MRI reconstruction challenge - Assessing brain MRI reconstruction models and their generalizability to varying coil configurations

arXiv

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arXiv 2020年

作者： Beauferris, Youssef Teuwen, Jonas Karkalousos, Dimitrios Moriakov, Nikita Caan, Matthan Yiasemis, George Rodrigues, Lúvia Lopes, Alexandre Pedrini, Helio Rittner, Letícia Dannecker, Maik Studenyak, Viktor Gröger, Fabian Vyas, Devendra Faghih-Roohi, Shahrooz Jethi, Amrit Kumar Raju, Jaya Chandra Sivaprakasam, Mohanasankar Lasby, Mike Nogovitsyn, Nikita Loos, Wallace Frayne, Richard Souza, Roberto Radiology and Clinical Neurosciences University of Calgary Canada Hotchkiss Brain Institute University of Calgary Canada Seaman Family Mr Research Centre Foothills Medical Center Canada Department of Medical Imaging Radboud University Medical Center Netherlands Department of Radiation Oncology Netherlands Cancer Institute Netherlands ICAI-AI for Oncology University of Amsterdam Netherlands Department of Biomedical Engineering and Physics Amsterdam Umc University of Amsterdam Netherlands School of Electrical and Computer Engineering University of Campinas Brazil Institute of Computing University of Campinas Brazil Computer Aided Medical Procedures Technical University of Munich Germany India Iitm India Department of Electrical and Software Engineering University of Calgary Canada Centre for Depression and Suicide Studies St. Michael's Hospital Canada Mood Disorders Program Department of Psychiatry and Behavioural Neurosciences McMaster University Canada

Deep-learning-based brain magnetic resonance imaging (MRI) reconstruction methods have the potential to accelerate the MRI acquisition process. Nevertheless, the scientific community lacks appropriate benchmarks to assess MRI reconstruction quality of high-resolution brain images, and evaluate how these proposed algorithms will behave in the presence of small, but expected data distribution shifts. The Multi-Coil Magnetic Resonance Image (MC-MRI) Reconstruction Challenge provides a benchmark that aims at addressing these issues, using a large dataset of high-resolution, threedimensional, T1-weighted MRI scans. The challenge has two primary goals: 1) to compare different MRI reconstruction models on this dataset and 2) to assess the generalizability of these models to data acquired with a different number of receiver coils. In this paper, we describe the challenge experimental design, and summarize the results of a set of baseline and state of the art brain MRI reconstruction models. We provide relevant comparative information on the current MRI reconstruction state-of-the-art and highlight the challenges of obtaining generalizable models that are required prior to broader clinical adoption. The MC-MRI benchmark data, evaluation code and current challenge leaderboard are publicly available. They provide an objective performance assessment for future developments in the field of brain MRI reconstruction. Copyright © 2020, The Authors. All rights reserved.

关键词： Inverse problems

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Survey of reduced workload and crewing strategies for ocean patrol vessels

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NAVAL ENGINEERS JOURNAL 2001年第2期113卷 29-44页

作者： Baker, C Krull, R Snyder, G Lincoln, W Malone, TB Clifford C. Baker CIE CHFEP is a senior staff scientist at Carlow International Incorporated. He has applied most of his 24 years of experience in the application of human engineering technology to maritime systems. Mr. Baker has directed much of Carlow's efforts to reduce ship workload and to improve human performance and maritime safety through application of human factors methods and data. He is a Certified Industrial Ergonomist (CIE) as well as a Certified Human Factors Engineering Professional (CHFEP). Both certifications were granted by Oxford Research where Mr. Baker also serves as an Advisory Board member. Russell D. Krull P.E. is a senior engineer with A&T/Proteus Engineering with more than 18 years of experi-ence in marine engineering naval architecture and program management including 16 years of active duty in the U.S. Coast Guard. Recent experience includes advanced ship design studies engineering software development technical support for the USMC Advanced Amphibious Assault Vehicle propulsion systems analyses ship structural engineering and cargo handling systems engineering. Mr. Krull has an M.S.E. in naval architecture and marine engineering and an M.S.E. in industrial and operations engineering from University of Michigan and a B.S. in ocean engineering from the U.S. Coast Guard Academy. Capt. Glenn L. Snyder USCG. Regrettably since this paper was originally written Capt. Snyder has passed away. At the time of his death he was an operations specialist assigned to the Coast Guard's Deepwater Capabilities Replacement Project as Chief of Human Systems Integration. He served as commanding officer of the patrol boat Cape George (WPB-95306) the icebreaking tug Biscayne Bay (WTGB-104) and the cutter Legare (WMEC-911). A 1975 graduate of the U.S. Coast Guard Academy Capt. Snyder held an M.A. in national security and strategic studies from the U.S. Naval War College and an M.A. in international relations from Salve Regina College. In addition he was a 1998 fellow of the Foreign Service

The U.S. Coast Guard is in the concept exploration phase of its Integrated Deepwater System (IDS) acquisition project. This project will define the next generation of surface, air and command, control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) assets used to perform the Coast Guard's missions in the IDS environment (>50 NM off the U. S. coastline). As part of early technology investigations, the needs exist to: (1) analyze the workload requirements of the IDS, (2) identify alternative means to perform ship's work, and (3) optimize ship manning consistent with ship workload, performance criteria, and the available tools and equipment aboard. To reduce shipboard work requires an understanding of the mission and support requirements placed on the vessel and crew, how these requirements are currently met, and how requirements might otherwise be met to reduce workload and crew size. This study examined currently implemented workload and manpower reducing approaches of commercial maritime fleets, U.S. and foreign navies, and foreign coastguards. These approaches were analyzed according to evaluation criteria approved by the IDS acquisition project team. From this, strategies for shipboard work reduction that may be considered for adoption by the IDS were identified and analyzed according to performance and costs factors. Ten workload-reducing strategies were identified: damage control, bridge, multiple crewing, engineering, risk acceptance, modularity, deck, enabling technologies, ship/personnel readiness, and operability and maintainability.

关键词： Naval vessels

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AAAI 2008 workshop reports

AAAI 2008 workshop reports

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作者： Anand, Sarabjot Singh Bunescu, Razvan Carvcdho, Vitor Chomicki, Jan Conitzer, Vincent Cox, Michael T. Dignum, Virginia Dodds, Zachary Dredze, Mark Furcy, David Gabrilovich, Evgeniy Göker, Mehmet H. Guesgen, Hans Hirsh, Haym Jannach, Dietmar Junker, Ulrich Ketter, Wolfgang Kobsa, Alfred Koenig, Sven Lau, Tessa Lewis, Lundy Matson, Eric Metzler, Ted Mihalcea, Rada Mobasher, Bamshad Pineau, Joelle Poupart, Pascal Raja, Anita Ruml, Wheeler Sadeh, Norman Shani, Guy Shapiro, Daniel Smith, Trey Taylor, Matthew E. Wagstaff, Kiri Walsh, William Zhou, Rong Department of Computer Science University of Warwick United Kingdom School of Electrical Engineering and Computer Science Ohio University United States Microsoft Live Labs United States computer science and engineering University at Buffalo United States Computer science and economics Duke University United States Intelligent Computing group of BBN Technologies Utrecht University Netherlands Department of Computer science Harvey Mudd College United States University of Pennsylvania United States University of Wisconsin United States Yahoo Research PricewaterhouseCoopers Center for Advanced Research United States Department of Computer science School of Engineering and Advanced Technology Massey University New Zealand Departent of Computer science Rutgers University United States Department of Computer Science Dortmund University of Technology. Germany ILOG Rotterdam School of Management Erasmus University Netherlands Donald Bren School of Information and Computer Sciences University of California Irvine United States Depatrment of Computer science University of Southern California United States IBM Almaden Research Center United States Department of Computer Information Technology Southern New Hampshire University United States Computer and Information Technology Program College of Technology Purdue University United States Hughes Program for Religion and Science Dialogue Oklahoma City University United States Department of Computer Science and Engineering University of North Texas United States School of Computing DePaul University United States Department of Computer Science McGill University Canada School of Computer Science University of Waterloo Canada Department of Software and Information Systems University of North Carolina Charlotte United States University of New Hampshire United States Microsoft Research Institute for the Study of Learning and Expertise Applied Reactivity Inc. United States NASA Ames Research Center Carnegie Mellon University West

AAAI was pleased to present the AAAI-08 Workshop program, held Sunday and Monday, July 13-14, in Chicago, Illinois, USA. The program included the following 15 workshops: Advancements in POMDP Solvers;AI Education Workshop Colloquium;Coordination, Organizations, Institutions, and Norms in Agent Systems, Enhanced Messaging;Human Implications of Human-Robot Interaction;Intelligent Techniques for Web Personalization and Recommender Systems;Metareasoning: Thinking about Thinking;Multidisciplinary Workshop on Advances in Preference Handling;Search in Artificial Intelligence and Robotics;Spatial and Temporal Reasoning;Trading Agent Design and Analysis;Transfer Learning for Complex Tasks;What Went Wrong and Why: Lessons from AI Research and Applications;and Wikipedia and Artificial Intelligence: An Evolving Synergy. Copyright © 2009, Association for the Advancement of Artificial Intelligence. All rights reserved.

关键词： Human robot interaction

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HCVMultiscaleDyn: A simulator for the multiscale model of hepatitis C virus dynamics

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AIP Conference Proceedings 2018年第1期1978卷

作者： Alexander Churkin Vladimir Reinharz Harel Dahari Danny Barash 1Department of Software Engineering Shamoon College of Engineering Beer-Sheva Israel 2Department of Computer Science Ben-Gurion Universty Beer-Sheva Israel 3The Program for Experimental and Theoretical Modeling Division of Hepatology Department of Medicine Loyola University Medical Center Maywood Illinois USA

Multiscale mathematical models that incorporate both intracellular and extracellular hepatitis C virus (HCV) dynamics have been developed in recent years to study HCV-host dynamics and antivirals mode of action and efficacy. They were built upon the standard HCV dynamic model that keeps track of uninfected hepatocytes, HCV-infected hepatocytes, and free virus in blood (for each there is a differential equation), along with a fourth equation that considers the intracellular viral RNA (vRNA) dynamics in an infected cell. A multiscale model with vRNA dynamics consideration is substantially more difficult to solve and the governing differential equations are stiff. In one of the derived differential equations there is also an integral involving the vRNA that is more accurately computed by considering previous iterations, impeding the use of canned solvers. To solve this problem we have chosen to implement a stable and efficient numerical method that belongs to the family of adaptive stepsize methods and is implicit, the Rosenbrock method. We provide a user friendly simulator called HCVMultiscaleDyn with a Graphical User Interface that applies this method and is useful to simulate viral dynamics during antiviral treatment.

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Student Space Missions – Facilitating Pathways to Success for Next Generation Professionals in Space

Student Space Missions – Facilitating Pathways to Success f...

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IAF Space Education and Outreach Symposium 2021 at the 72nd International Astronautical Congress, IAC 2021

作者： Bering, Edgar A. Khan, Shuhab Moges, Mequanint Hampton, Donald Mölders, Nicole Thorsen, Denise Dunbar, Bonnie J. Lefer, Barry L. Gamblin, Rachel B. Greer, Michael Greer, Presley Gunawan, Bryan Hernandez, Elizabeth Lehnen, Jamie Nguyencuu, Andy Piña, Megan Porat, Itay Prince, John R. Pessoa, Ana Gabriela Simmons, James Tovar, Chloe Ulinski, Alexandra Departments of Physics and Electrical Engineering University of Houston 3507 Cullen Blvd. #617 HoustonTX77204-5005 United States Department of Earth and Atmospheric Sciences University of Houston 3507 Cullen Blvd. #312 HoustonTX77204-5007 United States Department of Engineering Technology 4730 Calhoun Road #304 HoustonTX77204-4020 United States Geophysical Institute University of Alaska Fairbanks 2156 Koyukuk Drive FairbanksAK99775 United States Department of Aerospace Engineering Texas A&M University 701 H.R. Bright Bldg. #609B College StationTX77843-3141 United States Tropospheric Composition Program Earth Sciences Division NASA Headquarters 300 E St SW WashingtonDC20024 United States NASA Johnson Space Center Cimarron Software Services Inc. 2101 NASA Parkway HoustonTX77058 United States Alumni University of Houston 3507 Cullen Blvd. HoustonTX77204 United States UT Southwestern Medical Center 5323 Harry Hines Blvd DallasTX75390 United States Department of Computer Science University of Houston 3551 Cullen Blvd. #501 HoustonTX77204-3010 United States University of Pennsylvania School of Design 210 S. 34th St. PhiladelphiaPA19104 United States

ISBN: (纸本)9781713843177

The Undergraduate Student Instrumentation Project (USIP) was a NASA program created to engage undergraduate students in rigorous scientific research for the purposes of innovation and developing the next generation of professionals in space research. It is now run by the University of Houston using local resources. This student-led project, based on the 5E instructional model, is executed by the students from initial ideation of research objectives to the design, testing, and deployment of scientific payloads. The 5E Instructional model places the student at the center of knowledge building, while instructors facilitate interaction with content and guide the inquiry process. Since 2013, this project has been not only an effective vehicle for delivering STEM education but is also effective in increasing classroom engagement and interest in space. Space research is inherently interdisciplinary and crosscuts Geoscience, engineering, and Technology. The project is designed to integrate engineering, technology, physics, material science, and earth and atmospheric sciences as an important opportunity for the students to gain access to cross-disciplinary experiential research. In addition to classroom engagement, the students build their own payloads and ground instruments. This project increases students’ command of essential skills such as teamwork, collaboration, problem solving, technology, communication, innovation, and leadership. For the faculty, the project was an extended exercise in professional development, learning how to implement project level inquiry-based education on this scale. For the students, this formative experience continues to encourage the development of a much broader range of technical skills than is typically offered within an undergraduate degree. Furthermore, the extensive time and energy that students commit to this project promotes a strong sense of personal and professional responsibility and emphasizes the necessity of coherent teamwork.

关键词： Students

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THE CALLING(SM) NETWORK - A GLOBAL WIRELESS COMMUNICATION-SYSTEM

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第1期12卷 45-61页

作者： TUCK, EF PATTERSON, DP STUART, JR LAWRENCE, MH Calling Communications Corporation. 1900 West Garvey Ave South. Suite 200 West Covina CA 91790 USA. Chairman of Calling Communications Corporation. He is also the Managing Director of Kinship Venture Management Inc. the general partner of Kinship Partners 11 and a General Partner of Boundary the general partner of The Boundary Fund. As a venture capitalist he has founded or participated in founding several telecommunications companies including Calling Communications Corporation Magellan Systems Corporation manufactures of Global Positioning System receivers Applied Digital Access manufacturer of DS-3 test access and network performance monitoring equipment Endgate Technology Corporation specialists in satellite phased array antennas and Poynting Systems Corporation. now a division of Reliance Corporation manufacturers of fibre optic transport equipment. He was a founder of Kebby Microwave Corporation where he invented the first solid-state. frequency-modulated commercial microwave link system. The company was acquired by ITT Corporation where he rose to the position of V.P. and Technical Director of ITT North America Telecommunications Inc. Subsequently he was V.P. of Marketing and Engineering at American Telecommunications Inc. (ATC). He was founding Director of American Telecom Inc. a joint venture between ATC and Fujitsu and has served on more than 20 boards of directors including those of three public companies. He has authored articles on microwave engineering and telephone signalling and was a contributor to Reference Data For Radio Engineers. He is a graduate of the University of Missouri at Rolla where he was later awarded an honorary Professional degree and serves on its Academy of Electrical Engineering. Mr Tuck is a Senior Member of the IEEE a Fellow of the Institution of Engineers (Australia) a Professional Member of the AIAA and a registered professional engineer in three states. More than 25 years of experience in the telecommunications industry where he has been responsibl

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world's largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routeing, and light spacecraft technology, in part based on the work of the Jet Propulsion Laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modern basic and enhanced telephone services offered by telephone utilities in the urban centres of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide a service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain these economies of scale requires that the system use K(alpha)-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century.

关键词： LOW EARTH ORBIT SATELLITE COMMUNICATIONS FAST PACKET SWITCHING EARTH FIXED CELLS ADAPTIVE ROUTEING LIGHT SPACECRAFT K(A) BAND PHASED-ARRAY ANTENNAS

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