Showing papers by "Mitre Corporation published in 1982"

Matching Images to Models for Registration and Object Detection via Clustering

Abstract: A new technique is presented for matching image features to maps or models. The technique forms all possible pairs of image features and model features which match on the basis of local evidence alone. For each possible pair of matching features the parameters of an RST (rotation, scaling, and translation) transformation are derived. Clustering in the space of all possible RST parameter sets reveals a good global transformation which matches many image features to many model features. Results with a variety of data sets are presented which demonstrate that the technique does not require sophisticated feature detection and is robust with respect to changes of image orientation and content. Examples in both cartography and object detection are given.

High-capacity wavelength demultiplexer with a large-diameter GRIN rod lens.

Abstract: A high capacity (twelve-channel) fiber optic wavelength demultiplexer incorporating a large diameter GRIN rod lens and grating was developed and fully characterized. The demultiplexer operates over the 740–930-nm wavelength range with an average channel spacing of 17 nm. The insertion loss, measured and averaged over all twelve channels, was ~3 dB, and the average adjacent channel optical cross talk was 32 dB.

Very fast computation of the radix-2 discrete Fourier transform

Abstract: This paper develops and presents a radix-2 fast Fourier transform (FFT) algorithm that reduces the computational effort (as measured by the number of multiplications) to two-thirds of the effort required by most radix-2 algorithms. The resulting algorithm is similar to one obtained by applying a principle suggested by Rader and Brenner; however, its structure is particularly appealing when transforming pure real or imaginary sequences and/or symmetric or antisymmetric sequences; furthermore, memory requirements (other than those for storing the input data) do not grow with the size of the transform.

A testbed approach to the design of a computer communication network

Abstract: ideal simulations can 't predict real performance, but with this method Mitre didn't have to guess. They measured the performance of their routing system on the actual nodes.

A Specification Method for Specifying Data and Procedural Abstractions

Abstract: A specifilcation method designed primarily for specifying data abstractions, but suitable for specifying procedural abstractions as well, is described. The specification method is based on the abstract model approach to specifying abstractions. Several data abstractions and procedural abstractions are specified and a proof of implementation correctness is given for one of the data abstractions–a symbol table.

The linear-quadratic-gaussian problem for singularly perturbed systems†

Abstract: This paper addresses the general formulation of the linear-quadratic-gaussian (LQG) problem for stochastic singularly perturbed systems. It has been found that the time-Scale phenomena between the fast state variable and the stochastic variable plays a crucial role in formulating a meaningful LQG problem for the above system. A well-posed LQG problem for the stochastic singularly perturbed linear system with the fast state having a white noise component has been presented.

A Multilevel Secure Local Area Network

Abstract: This paper presents a high-level design for a local area network (LAN) that will support subscribers (terminals or hosts) operating at various security levels. Subscribers may be "single-level", which means they are untrusted and can operate at only one security level, or they may be "multilevel" and trusted to operate at a range of security levels [Nibaldi79].

Equalized Megahertz-Bandwidth HF Channels for Spread Spectrum Communications

Abstract: In this paper we discuss the use of skywave propagation paths in the HF band for spread spectrum communications involving coherent bandwidths of about one megahertz We present experimental data describing wide-bandwidth one-hop F-layer links, discuss real-time adaptive equalization procedures for wideband spread spectrum signaling on these links, and conclude with some recent measurements over equalized paths of up to 2000 km Two significant attributes of these equalized wideband channels are (1) time invariance over many seconds (typically ten), and (2) freedom from fading caused by the presence of multiple propagation modes Both are dependent on achieving mode isolation in the receiver through the use of wideband waveforms The measurement data was gathered in 1981 using MITRE's wideband HF test facility which consists of a mobile transmit terminal and a fixed receive terminal in Bedford, Massachusetts The transmit terminal is capable of generating signals for channel measurement and data communications testing The receive terminal is capable of real-time adaptive equalization over a 1024 MHz bandwidth, signal processing, and data recording The data presented here describes unequalized and equalized channel measurements

Beacon/radar video generator system for air traffic simulation

Abstract: Preprogrammed aircraft target information is stored in separate lists of beacon and radar target words each including azimuth, range and amplitude data for a designated target within the current one of a plurality of predetermined azimuth "half" sectors. For each radar target word whose starting and ending azimuth includes the current azimuth, its amplitude data is loaded into the range bin of one of a first pair of high speed RAM data stacks addressed by the range data of the target word. When the radar trigger occurs, the previously loaded data stack is read out sequentially bin-by-bin. An echo pulse is formed by a video data output control for each range bin containing a non-zero value. For a beacon target of valid azimuth, the amplitude data is loaded into the range bin of one of a second pair of data stacks addressed by the range data of the beacon target word. The same amplitude data is loaded into every eighth range bin for which the corresponding bit of the transponder 3/A or C code is a "1". The previously loaded stack beacon data is read out sequentially at a slightly faster rate for beacon targets than for radar targets to simulate the standard ATCRBS interpulse period. The data stacks for either beacon or radar targets are alternated so that one is available for loading while the other one is being read out.

A study of decision-making behavior of aircraft pilots deviating from a planned flight

Abstract: This paper outlines an investigation into the worth structures of pilots facing a deviation from a planned flight. A 'paper and pencil' simulation was used to frame the situation into which pilots interjected their own decision making skills in a simple ranking of candidate diversion airports with varying locational, navigational aid, radar and weather attributes. Using the conjoint measurement technique, attribute worth functions of 30 pilots were constructed. It was discovered that systematic differences in the worth functions of the pilots did not occur as a result of dividing the pilot sample according to any measure of flight hour experience. However, differences were found when the pilot sample was grouped according to grade of pilot certificate, type of pilot training, and type of flying most commonly done.

Partial Processing Satellite Relays for Frequency-Hop Antijam Communications

Abstract: Military satellite communications systems may be implemented with varying levels of satellite on-board processing. For frequency-hop (FH) spread-spectrum signals two options are the dehop-rehop transponder (DRT) and the symbol regenerative processor (SRP). This paper considers FH, M -ary FSK modulation in the presence of full band and worst case partial-band noise jamming. The relationships among end-to-end signal-to-noise ratio (SNR) performance or probability of bit errors and the uplink and downlink SNR are derived. For a DRT, an additional parameter is the satellite filter bandwidth W s since this may differ from the despread modulation bandwidth W r for a particular user access under TDMA variable-data-rate operation. The SNR performance in this case depends upon the ratio W_{s}/W_{r} a well as the uplink and downlink SNR. The resulting penalty in the link budget of the weaker of the uplink or downlink is much less than the mismatched ratio W_{s}/W_{r} and diminishes as the links become unbalanced. The SRP slightly outperforms the DRT but it is more complex and does not as easily accommodate variable data rates.

A Preliminary Neval Surveillance OBMS Sacurity

Abstract: This paper presents an informal security model for the use of data base management systems supporting Naval surveillance applications. The paper discusses why conventional security models are inadequate for data base needs. Also, the Naval surveillance system environment is described, followed by a description of the model and its application to Naval surveillance systems. The model itself is made up of subjects (the users), objects (the data), operators, and policies. The paper concludes with a discussion of directions for model evolution and the observation that, although designed for a particular class of data base applications, the model is surprisingly general.

A Slow Frequency Hopping Technique that is Robust to Repeat Jamming

Abstract: A frequency hopping technique capable of defeating the repeat jammer independent of the hop rate is presented This technique, random frequency shift keying/frequency hopping (FSK/FH), is described and analyzed Specific results are given for 2-ary, 4-ary and 8-ary random FSK/FH against repeat noise, repeat tone, and combined repeat tone and noise jamming with and without error correction coding These analyses show that random FSK/FH is an effective countermeasure to the repeat jammer

Comments on "Interference Analysis of Shuffle/Exchange Networks"

Abstract: The above paper1 claims to present an exact discrete time Markov chain model for interference analysis of shuffle exchange networks. We show that the solutions presented are inaccurate. This problem has also been considered in [1]–[3], where simpler and more general solutions are presented.

Non-mass-analyzed ion implantation equipment for high volume solar cell production

Abstract: Equipment designed for junction formation in silicon solar cells is described. The equipment, designed for a production level of approximately one megawatt per year, consists of an ion implanter and annealer. Low cost is achieved by foregoing the use of mass analysis during the implantation, and by the use of a belt furnace for annealing. Results of process development, machine design and cost analysis are presented.

Effect of Interface Design on Usability of Message Handling Systems

Abstract: Computer-based office support systems are designed to be used by people who view these systems as tools to accomplish tasks. For such users, the usefulness of a function is related to how well the interface to that function is designed. A comparison of two computer-based message systems shows that the amount of use received by a function supporting a secondary task is related to how easy that function is to use. It may be necessary to forego some system-wide power to provide user aids that improve usability of secondary functions.

Kernel Isolation for the PDP-11/70

Abstract: A security kernel is that part of operating system software responsible for controlling access to files and other resources. This report gives a paradigm for showing that a kernel can protect itself from destruction or tampering by user software, on the basis of the hardware and kernel software properties. An illustrative proof is carried out for DEC PDP-11 /70 hardware, with kernel properties that would be typical for this machine.

On board processing for future satellite communications systems: Comparison of FDM, TDM and hybrid accessing schemes

Abstract: Several satellite uplink and downlink accessing schemes for customer premises service are compared. Four conceptual system designs are presented: satellite-routed frequency division multiple access (FDMA), satellite-switched time division multiple access (TDMA), processor-routed TDMA, and frequency-routed TDMA, operating in the 30/20 GHz band. The designs are compared on the basis of estimated satellite weight, system capacity, power consumption, and cost. The systems are analyzed for fixed multibeam coverage of the continental United States. Analysis shows that the system capacity is limited by the available satellite resources and by the terminal size and cost.

A Direct Sequence Spread-Spectrum Modem for Wideband HF Channels

Abstract: The use of spread-spectrum techniques to reduce jamming vulnerability and probability of intercept is fundamental in many military communication systems. This paper describes the design of an experimental spread-spectrum modem (modulator-demodulator) built to interface with an existing HF test facility that offers an equalized 1 MHz bandwidth over skywave paths. The modem uses differential binary and quadrature phase shift keying data modulation and direct-sequence bi-phase spreading techniques. Programmable charge-coupled-device matched filters, which allow symbol-to-symbol code agility, and coherent pre-detection integration provide up to 30 dB of processing gain at a 500 bits/second data rate. Flexible data rate and range (time-of-arrival) tracking to maintain bit synchronization are incorporated into the system.

The Teleradiology Field Demonstration

Abstract: The MITRE Corporation has designed a system for gathering, storing, transmitting over telephone lines, subsequent restoring and recalling radiological cases consisting of multiple images and textual case data. This system has been implemented at four satellite sites and one central reading site. An evaluation is being conducted to determine the accuracy, reliability, user acceptance, and utility of the system. This paper describes the context of the demonstration, describes the system operation and its principal components, emphasizing the technical characteristics of image gathering, processing, transmission, storage and display.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fast algorithms for signal processing using finite field operations

Abstract: A signal processing system employing digital arithmetic can be made equivalent to a set of interconnected subsystems each using finite field operations to alleviate effects of round-off noise, particularly in recursive structures. The realization of the subsystems involves the multiplication of polynomials over a finite field. Cyclic convolutions may be represented as polynomial multiplications, in a residue class ring modulo the polynomial (xk-1). Fast algorithms arise when the ring is decomposed into a direct product using its minimal ideals, the orthogonality relationships between the idempotents of the minimal ideals resembling the decomposition properties of the Chinese remainder theorem for real polynomials. The resulting component polynomial multiplications involve elements with smaller degrees. A transform domain, based upon an nthroot of unity in an extension field, offers an alternative domain for performing the component operations. Polynomial multiplications are equivalent to the vector inner product of the corresponding transform coefficients. The minimal ideal components, when mapped into the transform domain, have nonzero coefficients only in predetermined subsets, the cyclotomic subsets, which permits one coefficient to generate all others by successively forming its powers.

An FDMA system concept for 30/20 GHz high capacity domestic satellite service

Abstract: The paper summarizes a feasibility study of a multibeam FDMA satellite system operating in the 30/20 GHz band. The system must accommodate a very high volume of traffic within the restrictions of a 5 kW solar cell array and a 2.5 GHz bandwidth. Multibeam satellite operation reduces the DC power demand and allows reuse of the available bandwidth. Interferences among the beams are brought to acceptable levels by appropriate frequency assignments. A transponder design is presented; it is greatly simplified by the application of a regional concept. System analysis shows that MSK modulation is appropriate for a high-capacity system because it conserves the frequency spectrum. Rain attenuation, a serious problem in this frequency band, is combatted with sufficient power margins and with coding. Link budgets, cost analysis, and weight and power calculations are also discussed. A satellite-routed FDMA system compares favorably in performance and cost with a satellite-switched TDMA system.

A concept for a fuel efficient flight planning aid for general aviation

Abstract: A core equation for estimation of fuel burn from path profile data was developed. This equation was used as a necessary ingredient in a dynamic program to define a fuel efficient flight path. The resultant algorithm is oriented toward use by general aviation. The pilot provides a description of the desired ground track, standard aircraft parameters, and weather at selected waypoints. The algorithm then derives the fuel efficient altitudes and velocities at the waypoints.

Numbering Formats for Hierarchic Lists

Abstract: Sixteen people scanned lists of hierarchically numbered items to perform various tasks. For tasks involving location of individual items, a list format with complete numbering permitted superior performance. For tasks requiring perception of list structure, an alternative format with implicit numbering was equally good if not better.

Design trade-offs in antijam military satellite communications

Abstract: HIS paper outlines technical parameters, boundary values, and antijam trade-offs among parameters of satellite communications systems designed for military use. Military satellite communications has grown steadily in the United States, NATO, and the Soviet.Union, to become an essential element of both general-purpose and modern command, control, communications (C3) structures. The features that distinguish these systems include broad area coverage for global connectivity of commanders and forces, and instant reconfiguration flexibility to allow a single system to support varied services (broadcast, point-to-point voice, data, and teletype for tactical, strategic, or logistic users). Design principles and propagation variations related to the intervening atmosphere and ionosphere are understood. However, the broad global visibility of a satellite, which is the source of its utility and flexibility to military operations, is also its Achilles heel: the satellites are visible to potential jammer locations. The utility of satellite communications will lead to more pervasive and general use, which in turn requires attention to operation in a jamming environment. This article discusses the design of systems for such operation.