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.< >
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.
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).
The methods of impedance or admittance measurements are discussed for a variety of biological cells. The aim of this paper is the description of the techniques of measurements and the analysis of systematic errors ari...
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The methods of impedance or admittance measurements are discussed for a variety of biological cells. The aim of this paper is the description of the techniques of measurements and the analysis of systematic errors arising from electrode arrangements and measuring systems. Detailed discussion on the nature of membrane admittance of biological cells can be found elsewhere.
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...
A tutorial is presented on the applications of signal and image processing to medicine that covers both one- and multidimensional signals, such as EEG, ECG, IR, ultrasound signals, etc., and two- and three-dimensional...
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A tutorial is presented on the applications of signal and image processing to medicine that covers both one- and multidimensional signals, such as EEG, ECG, IR, ultrasound signals, etc., and two- and three-dimensional images, such as CAT scanners, MRI magnetic resonance imaging, ultrasound images, holographic images, etc. The analysis problems covered range from the inverse scattering problem through signal/image enhancement in noise and filtering, parameter identification, pattern discrimination and recognition, coding, and data reduction to visualization and 3-D manipulation.< >
Transesophageal atrial pacing (TAP) has been proposed as a noninvasive alternate modality of cardiac stress for patients who cannot perform an adequate exercise stress test. Present computer methods for processing the...
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Transesophageal atrial pacing (TAP) has been proposed as a noninvasive alternate modality of cardiac stress for patients who cannot perform an adequate exercise stress test. Present computer methods for processing the exercise ECG are inadequate in analyzing the unique surface ECG recorded during a TAP stress procedure. This is due to the presence of large simulator-induced pacing artifacts which confound computer beat identification. The authors have developed hardware to suppress the large pacing artifact, and a software method to detect the R wave, determine sustained capture, and calculate beat-by-beat and average ST-segment level, St slope, R-wave amplitude, and instantaneous RR interval and heart rate. They employ five different computer methods (single-point, average, weighted-average, linear least-squares and parabolic least-squares) in ST-segment measurements. They demonstrate the deficiency of present exercise ECG computer methods in processing the ECG during stress and show the significantly enhanced performance of their own technique on real ECG data.< >
A conference key distribution system (CKDS) can provide a common secret communication key to a set of M stations. A CKDS based on Lagrange interpolating polynomial is introduced. It is easy to see that breaking this s...
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A conference key distribution system (CKDS) can provide a common secret communication key to a set of M stations. A CKDS based on Lagrange interpolating polynomial is introduced. It is easy to see that breaking this system is equivalent to break the Diffie-Hellman public-key distribution system. This conference key is selected by the conference chairstation and hidden in the Lagrange interpolating polynomial. Recovering this key by each participating station only requires M-1 multiplications and M-2 additions over a finite field GF(P).< >
An approach to the analysis of event related potentials (ERP) based on information theory is described. The amount of information in cortical potentials evoked by words briefly presented by tachistoscope is measured b...
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An approach to the analysis of event related potentials (ERP) based on information theory is described. The amount of information in cortical potentials evoked by words briefly presented by tachistoscope is measured by a transinformation method. The inputs to the communication channel are four word categories. One category is composed of pleasant words, another of unpleasant words, both drawn from the Osgood semantic differential research, and two categories are composed of word stimuli related to a psychiatric patient's complaints. The patients chosen for study exhibit either phobias or pathological grief reactions. The method allows ERP's to be mapped into transinformation profiles that reveal time intervals during the poststimulus ERP favorable to the transmission of information concerning the word category presented. The transinformation model results for actual and synthetic data are discussed.
This paper reports on the development of an on-line automated medical record system suitable for nursing homes. The software was written in standard MUMPS (Massachusetts General Hospital Utilities Multi-programming Sy...
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