A novel ID-based cryptographic scheme for implementing a public-key cryptosystem and signature is proposed. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to cho...
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A novel ID-based cryptographic scheme for implementing a public-key cryptosystem and signature is proposed. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to choose his/her name or network address as his/her public key. This eliminates the needs of a large public field and the exchange of private or public keys. The major advantage of the ID-based cryptosystem based on this scheme over other published ID-based cryptosystems is that the number of users can be extended to t*L users without degrading the system's security even when users conspire, where L is the number of the system's secrets, and t is the number of factors in p-1, where p is a large prime number.< >
A password authentication mechanism based on the public-key distribution cryptosystem is proposed. The scheme uses an authentication table to replace the traditional password file. With this scheme, even if the authen...
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A password authentication mechanism based on the public-key distribution cryptosystem is proposed. The scheme uses an authentication table to replace the traditional password file. With this scheme, even if the authentication table is comprised, the system security is preserved. The user's password is effectively bound to the user's identification in a timely, efficient, and simple manner.< >
Over the last several years the power of personal computers (PC) in enhancing teaching effectiveness in both classroom and laboratory has become universally recognized. The objective of this paper is to describe how P...
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We propose that short-period doping superlattices are suitable for the enhancement of a third-order susceptibility arising from free carriers in nonparabolic energy subbands. The inherent advantage lies in the ability...
We propose that short-period doping superlattices are suitable for the enhancement of a third-order susceptibility arising from free carriers in nonparabolic energy subbands. The inherent advantage lies in the ability to simply engineer the superlattice potential profile, yielding control of miniband energy dispersion. We consider short-period GaAs doping superlattices composed of uniformly doped donor and acceptor layers, and planar-doped n- and p-type monolayers separated by intrinsic regions. Calculations of the electronic structure of compensated and n-type noncompensated n-i-p-i superlattices incorporating miniband dispersion at nonzero temperature are reported. We show that small modulations of the superlattice potential lead to large subband nonparabolicities and we calculate a twentyfold improvement in the third-order susceptibility over bulk GaAs at room temperature, comparable to that predicted for GaAs/AlGaAs compositional superlattices.
作者:
BROWN, DWREPP, JRTAYLOR, OSD. W. Brown is an engineer at the Westinghouse Research and Development Center. He received a B.S. in mechanical engineering from Michigan Technological University and an M.S.
in mechanical engineering from Michigan State University. Mr. Brown joined Westinghouse in 1986 and has since worked on such projects as the testing and analysis of current collection apparatus the design of shaft and bearing arrangements for high speed electrical motors and the design of a submersible electric motor. He also has experience in the use and analysis of fiber-reinforced composites at room temperature and at cryogenic temperatures. This knowledge of composites was applied to a study involving a fibrous composite robot arm. Mr. Brown is working on the rotor design of a cryogenically cooled AF generator and also the design of the vertical motor test facility for the Motor Silencing Program. Jeffrey R. Repp is a senior engineer with Westinghouse Research and Development Center. He received a B.S. in electrical engineering from Pennsylvania State University
an M.S. in electrical engineering from the University of Cincinnati and an M.B.A. in management/industrial management from Xavier University. Mr. Repp has 13 years of experience in the field of electrical engineering
specializing in the design and analysis of electromagnetic devices. This experience includes the development design testing and analysis of a wide variety of electric motors ranging from fractional horsepower permanent magnet motors through large (10000 hp) synchronous and induction motors. Mr. Repp has been directly involved in the electromagnetic and thermal analyses of machines utilizing state-of-the-art finite element and computer graphic techniques. Most recently he has been concerned with the development of electronically commutated permanent magnet (brushless dc) products. Mr. Repp is a Member Institute of Electrical and Electronics Engineers IEEE Power Engineering Society. O. S. Taylor is manager of electromechanical applications
at the Westin
Mr. Taylor has more than 18 years of experience in the field of research and development engineering. Since joining Westinghouse in 1974 he has been involved in the design and development of advanced electrical machin...
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Mr. Taylor has more than 18 years of experience in the field of research and development engineering. Since joining Westinghouse in 1974 he has been involved in the design and development of advanced electrical machinery including large, high power density motors for electric drive ship propulsion, pulsed homopolar generators for electromagnetic launchers, high current density contacts for switching applications, research in automated manufacturing, and robotic system development. He is currently managing a section that deals with rotating power equipment for military applications, with emphasis on thermal and electromagnetic modeling. ABSTRACT A demonstration submersible outboard electric motor/ propulsor has been designed, built, and successfully tested. This concept involves mounting a propeller directly inside a rotor of a specially designed induction motor. This motor/ propulsor has the advantages of direct seawater cooling and bearing lubrication, direct drive, shrouded propeller, variable positioning, easy access, and high maneuverability. The motor/propulsor is readily adaptable to dual, independently-controlled and contra-rotating propellers without the need for gears. The concept has been investigated conceptually for application to primary propulsion, secondary propulsion, and pod drives, for amphibious, surface, and undersea vehicles.
This paper documents an experiment performed by The Johns Hopkins University Applied Physics Laboratory to measure the effect of inserting a data bus into a combat system. The experiment was conducted at the Aegis Com...
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This paper documents an experiment performed by The Johns Hopkins University Applied Physics Laboratory to measure the effect of inserting a data bus into a combat system. The experiment was conducted at the Aegis computer Center located at the Naval Surface Weapons Center in Dahlgren, Virginia (NSWC/DL). The purpose of the experiment was to determine whether or not the Aegis Weapon System (the core of the Aegis Combat System) could be operated with a portion of its point-to-point interelement cables replaced by a data bus. The data bus chosen for the experiment employs message broadcasting with receiver selection. A primary goal of the experiment was to minimize the amount of Aegis computerprogram changes required to accommodate the data bus. The results presented in this paper will show that the experiment was a success. Key certification tests were passed with no computerprogram changes to the tactical elements and minimal changes in the Aegis tactical executive (ATES) program (less than 110 words changed).
An approach to coordination of cooperating concurrent processes, each capable of error direction and recovery, is presented. Error detection, rollback, and retry in a process are specified by a well-structured languag...
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An approach to coordination of cooperating concurrent processes, each capable of error direction and recovery, is presented. Error detection, rollback, and retry in a process are specified by a well-structured language construct called recovery block. Recovery points of processes must be properly coordinated to prevent a disastrous avalanche of process rollbacks. The approach relies on an intelligent processor system (that runs processes) capable of establishing and discarding the recovery points of interacting processes in a well coordinated manner such that a process never makes two consecutive rollbacks without making a retry between the two, and every process rollback becomes a minimum-distance rollback. Following a discussion of the underlying philosophy of the author's approach, basic rules of reducing storage and time overhead in such a processor system are discussed. Examples are drawn from the systems in which processes communicate through monitors.
The author describes a personal-computer software package recently incorporated in the power engineeringprogram at Northeastern University. The package includes a set of computerprograms which can be utilized to sup...
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The author describes a personal-computer software package recently incorporated in the power engineeringprogram at Northeastern University. The package includes a set of computerprograms which can be utilized to support classroom instruction and student design projects. The programs cover matrix operations, symmetrical components, line constant, steady-state operation of transmission lines, power flow (100 buses), symmetrical short circuits (100 buses), short circuits (100 buses), transmission-line transients, and transient stability. The computerprograms, the way they are utilized, and initial student reaction are discussed. It is concluded that the availability of the power system analysis and design software package has extended classroom capabilities and enhanced student interest in power engineering courses. The reaction of students to the software has been positive, and it has allowed them to work on more difficult and realistic problems and make it an innovative tool in the learning process.< >
The development of a CIM (computer Integrated Manufacturing) environment requires that inspection processes be linked to databases containing the design data. Increased emphasis on flexibility must not be bought at th...
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Advances in technology coupled with the inefficiency of the conventional von-Neumann type architecture in handling database systems have motivated the design and implementation of the so called database machines. Unfo...
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