Showing papers by "RAND Corporation published in 1978"

Values of Large Games II: Oceanic Games

Abstract: A value theory is developed for voting games in which a sizable fraction or the total vote is controlled by a few major players and the rest is distributed among a continuous infinity of individually insignificant minor players. The latter are referred to collectively as an “ocean,” to suggest the total lack of order or cohesion that is assumed.

Aircraft flight instrument display system

Abstract: Apparatus for providing an integrated display of flight instrument parameters on the screen of a single cathode ray tube is presented. The synthetically generated symbology provides the pilot with an integrated display of substantially all aircraft attitude and flight path command and control parameters including attitude and magnetic heading, barometric and radiometric attitude, vertical spread, critical take-off speeds, true airspeed and Mach airspeed, flight path angle, flight director path control commands, and mode annunciation for the flight director and automatic pilot systems.

An overview of pattern-directed inference systems

Abstract: Pattern-directed inference systems are programs that look for interesting or important situations occuring as patterns in their input or memory data. These patterns select pieces of program code to be executed. In this chapter a brief overview of pattern-directed inference systems is presented, including an historical perspective, a review of basic concepts, and a survey of current work in this area. Examples of the best known type of pattern-directed inference system, the production system, are presented and discussed in detail.

An interference matching technique for inducing abstractions

Abstract: A method for inducing knowledge by abstraction from a sequence of training examples is described. The proposed method, interference matching, induces abstractions by finding relational properties common to two or more exemplars. Three tasks solved by a program that uses an interference-matching algorithm are presented. Several problems concerning the description of the training examples and the adequacy of interference matching are discussed, and directions for future research are considered.

A Patrol Car Allocation Model: Capabilities and Algorithms

Abstract: A computer program has been designed for specifying the number of police patrol cars that should be on duty in each geographical command of a city at various times of day on each day of the week. It incorporates, by user option, nearly all the desirable features of earlier allocation programs, together with several improvements. It calculates performance statistics for the current allocation of patrol cars or any allocation proposed by the user. In addition, it has two prescriptive capabilities: 1 determining the minimum number of patrol cars needed during each tour in each command to meet specified constraints on performance measures, and 2 allocating a specified total number of car-hours by time and/or geography so as to optimize one of several available objective functions. The main technical innovation in the model is that it allows one tour in each day to overlay two other tours. A heuristic algorithm allocates car-hours when there is such an overlay tour; it is optimal when the overlay tour has the same duration as the tours it overlays.

Using Simulation to Develop and Validate Analytic Models: Some Case Studies

Abstract: Simulation models are generally costly tools to use in systems analyses. Whenever applicable, a simple analytic model is preferable. However, in many cases the conditions assumed by solvable analytic models do not hold in the real world; hence an analyst would hesitate to use them. A simulation can be used to suggest an appropriate approximate model and to determine how good an approximation a given analytic model is. We show how simulations of New York City's fire and police operations have been used to develop and validate simple analytic models that are now being used to analyze the deployment of resources in these two services.

Paired least recently used block replacement system

Abstract: A set associative cache buffer organized with 2 n blocks per set requires only 2n-1 age bits for determining the replacement block within a set. When the cache buffer is addressed and the data sought is not found therein, the age bits determine which block of data in the set should be replaced with new data from the main memory. The block replaced may be either the least recently used block or one of the two least recently used blocks. The replacement logic is such that the buffer may be expanded from two to four blocks per set with minimal impact on the replacement logic. In addition, provision is made for disabling faulty blocks thus allowing the cache buffer and main memory behind it to be utilized in a degraded mode.

A Patrol Car Allocation Model: Background

Abstract: Before designing a computer program for allocating police patrol cars by time and geography, a review was undertaken of previously existing programs of this type. Nearly all of the programs calculated queuing statistics for the collection of patrol cars by assuming a steady-state system with calls for service arriving within priority levels according to Poisson processes and having independent, identical, exponentially distributed service times. Unavailabilities of patrol cars for reasons other than calls for service were handled in the models either by artificially increasing the arrival rate of calls or by assuming that the number of servers is smaller than the number of patrol cars. Some programs calculated additional performance measures such as travel times and preventive patrol frequencies. All the programs had the capabilities to describe performance statistics for an allocation proposed by the user, but they differed in their capabilities to prescribe desirable allocations. None of the programs had achieved general acceptance because each had virtues and inadequacies not present in the others.

Principles of pattern-directed inference systems

Abstract: The general class of pattern-directed inference systems (PDISs) is defined and its general properties are investigated. Within a taxonomy of PDISs, the special properties of rule-based systems and two subclasses, production systems and transformation systems, are considered in detail. A comparison between these PDIS properties and contemporary information processing conceptions of human cognition suggests that PDISs provide an excellent basis for cognitive modeling. Principles for knowledge representation and system architecture are developed that suggest guidelines for controlling the combinatorial explosion that will accompany efforts to implement intelligent systems with extensive amounts of knowledge.

Care of the aged: old problems in need of new solutions.

Abstract: Long-term care for the aged in the United States is overly dependent upon the nursing home. This hospital-like model for long-term care is particularly inappropriate since it imposes a medical solution on a variety of social problems. An adequate long-term care program requires a range of resources in the community as well as in institutions; sheltered housing options seem a desirable alternative to the nursing home. To ensure the quality of nursing home care, the present focus on setting standards for care activities should be abandoned in favor of a focus on care outcomes (physical, mental, and social). In an effort to change our present perverse incentives in the nursing home industry, the proposal is made that nursing homes be reimbursed according to the degree to which patient outcomes meet predicted outcomes.

Flow in heated curved pipes

Abstract: The fully developed laminar flow in a heated curved pipe under the influence of both centrifugal and buoyancy forces is studied analytically. The pipe is assumed to be heated so as to maintain a constant axial temperature gradient. Both horizontal and vertical pipes are considered. Solutions for these two cases are obtained by regular perturbations in the Dean number and the product of the Reynolds and Rayleigh numbers; the solutions are therefore limited to small values of these parameters. Predictions of the axial and secondary flow velocities, streamlines, shear stress, temperature distribution and heat transfer are given for a representative case.

Autonomous fault diagnosis for disk drive using an internal microprocessor

Abstract: A disk drive control system incorporating an internal microprocessor and internal testing capabilities. The disk drive control system is capable of simulating drive operation without carriage motion so as to test substantially all functional subsystems of the disk drive. The test technique comprises the exercising of subsystems and a diagnosis of operations according to a hierarchy of interdependence of subsystem operation.

Pull-type agricultural machine

Abstract: The present invention relates to pull-type harvesting machines such as mower-conditioners and comprises a main frame fitted with ground-engaging wheels, a header adjustably mounted on and forwardly of the main frame and comprising drum type mower units, lifting means operable to move the main frame relative to the ground and the header relative to the main frame and an arched drawbar pivotally attached to the main frame and pivotable over the header from a machine operative position to a machine transport position and vice versa.

Performance monitor apparatus and method

Abstract: Performance monitor apparatus is adapted to monitor various computer program events such as the length of time required to execute a particular program, the number of times a particular program or instruction sequence is executed during some predetermined period, etc. The apparatus includes a buffer for receiving an instruction data word from a data processor and for temporarily storing the data word, a register having a plurality of bistable elements each of which is adapted to produce either a first or second output signal in response to receipt of a first or second operation signal respectively and receipt of a select signal, a select logic circuit for applying a select signal to a particular bistable element identified by certain bits of the instruction data word stored in the buffer, and an operation logic circuit for supplying to the bistable elements either a first or second operation signal as determined by certain other bits of the instruction data word stored in the buffer. Each bistable element represents a different event or occurrence in a computer program being monitored and the signals produced by the bistable elements indicate the nature of the monitoring operation to be performed. The signals are supplied to timing and counting apparatus which then either measures the time over which the signals are produced or increments a count in response to receiving the signals.

Transfer of Emergency Service Deployment Models to Operating Agencies

Abstract: Six deployment models for emergency service agencies were developed, field-tested, and documented during a two-year period ending October 1975. During the following eighteen months, records were kept of the extent to which the models were acquired by operating agencies and actually used for making deployment changes. The number of acquisitions ranged from zero for one model to 39 for another. Over half of those who acquire these models actually use them, and, except for one model, nearly all users made operational changes based on the output. Differences among the models illuminate the implementation process.

Sectorized data path following servo system

Abstract: A servo system for accurately positioning a transducer relative to data paths on a recording medium by detecting sync and servo signals from two parallel abutting servo tracks sharing a common longitudinal boundary within circumferentially spaced sectors of the medium. Within each sector of the recording medium, two servo waveforms of different frequencies in two abutting servo tracks are preceded by a sync reference waveform of the same frequency in both servo tracks which is used as a reference for a phase locked oscillator, connected to the transducer, generating a pair of modulation signals that are to be mixed with transducer signals from both servo waveforms. A pair of servo channels are provided for receiving the pair of modulation signals and the servo signals for deriving an imbalance error signal representing deviation of the transducer from the center line of a data path, which is the projection from the sectors of the common longitudinal boundary between servo tracks. The imbalance error signal is used to center the transducer on the data path.

Agricultural machine structure

Abstract: The present invention relates to a harvesting machine such as a mower-conditioner and comprises a header with a subframe, the subframe comprising a transverse upperbeam, opposed downwardly-extending legs connected thereto, and a lower transverse beam interconnecting and extending between the legs; the upper and lower beams and the legs together forming a rigid, generally rectangular structure. The header further also comprises at least one rotatable cutter unit having a mounting shaft detachably mounted between the upper and lower beams at a location inbetween the legs.

Electro-optical multiplexer having multiple frequency resonant excitation

Abstract: An improved optical multiplexer or demultiplexer device has a plurality of electrodes disposed on opposing surfaces of an electro-optically active plate that are resonantly excited at fundamental and harmonic frequencies for varying the effective index of refraction of the plate between the electrodes, thus coupling light successively between a first optical guide and selected ones of a plurality of optical guides.

Recreational vehicle sewer hose support

Abstract: A support for a flexible sewer hose attached to an RV. The support has at least two elongate, semi-circular sections which are relatively slidable to adjust the length of the support. Fastening means lock the sections once adjusted. The support is secured to the hose by flexible ties or securement means attachable to the hose.

Fail operational dual electromechanical servo actuator for aircraft with model monitoring

Abstract: The dual electromechanical servo actuator comprises two electric servo motors coupled through differential gearing to position an output member in accordance with an input signal. Tachometer generators coupled to the respective output shafts of the servo motors, (and normally integral with the motors) provide rate feedback signals to the respective inputs of the servo amplifiers driving the respective motors. An electronic model of the dual servo actuators responsive to the input signal provides a rate signal simulating the tachometer responses to the input signal. A monitor compares the two tachometer signals and provides a failure signal when the difference therebetween exceeds a predetermined threshold. The monitor also simultaneously compares the model rate ouptut with the individual tachometer signals to determine which of the two servo channels has failed. The monitor circuits apply a brake to the servo motor output shaft of the failed channel. The remaining channel continues to properly position the output member through the differential gearing. For certain applications of the invention the monitor continues to compare the model rate output with the tachometer signal from the operating channel so as to detect a failure of the second channel and provide a fail passive condition.

Apparatus for scaling memory addresses

Abstract: Apparatus for scaling addresses received by a memory module in a modular requestor-memory system in which standard memory modules may be of a discretely variable size and utilized in a plurality of positions in an overall contiguous memory addressing scheme. In particular, this scaling apparatus enables a modular memory which is only partially populated, i.e., only able to respond to a subset of the set of all addresses available, to be located in any one of several positions representing different addressing ranges. This is accomplished without modification of the memory module itself. The memory module knows its discrete capacity, or size, by virtue of the population of the memory array storage locations (array cards) contained therein. The memory module then uses this information to scale, or strip off, the appropriate number of bits from the gross address to allow addressing of the restricted number of memory locations present in the memory module.

Interferometric protective system for vehicles

Abstract: A base band transmitter cooperates with dual base band receiver antennas, a single receiver channel, and a tapped delay correlator device for the prevention of vehicular collisions, the configuration effectively narrowing the normally wide base band antenna pattern to span a single predetermined forward traffic lane.

The role of partial and best matches in knowledge systems

Abstract: Partial matching is a comparison of two or more descriptions that identifies their similarities. Determining which of several descriptions is most similar to one description of interest is called the best-match problem. Partial and best matches underlie several knowledge system functions, including analogical reasoning, inductive inference, predicate discovery, pattern-directed inference, semantic interpretation, and speech and image understanding. Because partial-matching is both combinatorial and ill-structured, admissible algorithms are elusive. Economical solutions require very effective use of constraints that apparently can be provided only by globally organized knowledge bases. Examples of such organizations are provided, and promising avenues of research are proposed.

Automatic twine wrapping apparatus

Abstract: In a crop roll forming machine having cooperating upper and lower bale forming means there is provided an improved automatic twine wrapping mechanism for binding a completed crop roll with binding material. The automatic twine wrapping mechanism is triggered by one of either two trip devices to automatically effect the serial steps of the twine wrapping cycle.

Magnetic recording signal equalization apparatus

Abstract: Magnetic recording apparatus including signal equalization means for recording data so as to obtain read pulses therefrom which are symmetrical about their peak and substantially narrowed at both the base and half amplitude points whereby increased packing density may be achieved without attendant peak shift, the equalization being provided by means for generating an ac bias signal in conjunction with data transitions and associated equalizer transitions referenced to the bias signal for application to magnetic recording means.

Survey of protocol definition and verification techniques

Abstract: Techniques for definition and verification of computer network protocols have progressed significantly in the past two years to the point where complex real world protocols such as HDLC, X.25, and Cyclades TS can now be analyzed. This success is largely due to the combination of two apparently divergent approaches — state transitions, and assertion proofs — and to the greater automation of the verification process. This paper summarizes and compares some of the more recent work in this field, emphasizing the common underlying principals of different techniques.