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Showing papers by "Naval Postgraduate School published in 1988"


Journal ArticleDOI
TL;DR: In this article, a linear theoretical analysis of the equatorial β-plane wave-CISK was carried out with a focus on the Kelvin modes, and it was shown that two types of CISK modes may arise from an interaction of vertical modes.
Abstract: Two categories of theories have been proposed to explain the observed tropical intraseasonal oscillations whose main periodicity is between 30–50 days: (i) those based on eastward propagating Kelvin waves maintained by cumulus heating; and (ii) those based on interactions with stationary oscillations of the basic state. Recent numerical modeling studies have simulated certain important aspects of the oscillation particularly the slower propagation speed as compared with the normal Kelvin waves. Motivated by these results which lend support to the first category, a linear theoretical analysis of the equatorial β-plane wave-CISK was carried out with a focus on the Kelvin modes. Our results show that two types of CISK modes may arise from an interaction of vertical modes. For heating with a maximum in the lower troposphere, the instability is due to the lowest internal mode which gives a stationary, east-west symmetrical structure. When heating is maximum in the midtroposphere, eastward propagating ...

165 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a status report on the present understanding of the physics of atom ejection by ion bombardment and indicate the contributions of molecular dynamics simulations to this research area.
Abstract: This article has two primary objectives: to present a status report on our present understanding of the physics of atom ejection by ion bombardment and to indicate the contributions of molecular dynamics simulations to this research area. Because this application of molecular dynamics is relatively unfamiliar, basic simulation techniques useful in open systems are described in some detail. While this review discusses the current situation, explanations and historical background are necessarily included to place problems in perspective.

154 citations


Journal ArticleDOI
TL;DR: A description is given of an approach to rapid prototyping that uses a specification language (the Prototype-System Description Language, PSDL) integrated with a set of software tools including a rewrite system, a syntax-directed editor with graphics capabilities, a software base, a design database, and a design-management system.
Abstract: A description is given of an approach to rapid prototyping that uses a specification language (the Prototype-System Description Language, PSDL) integrated with a set of software tools. including an execution support system, a rewrite system, a syntax-directed editor with graphics capabilities, a software base, a design database, and a design-management system. The prototyping language lets the designer use dataflow diagrams with nonprocedural control constraints as part of the specification of a hierarchically structured prototype. The resulting description is free from programming-level details, in contrast to prototypes constructed with a programming language. The discussion covers the language and method, rewrite subsystem, design manager, software base, and execution support. >

127 citations


Book
01 Jan 1988
TL;DR: This chapter discusses Simulation Modeling, Modeling Aspect of Simulation, and the Properties of Pseudo-Random Variables.
Abstract: MODELING AND CRUDE SIMULATION Definition of Simulation Golden Rules and Principles of Simulation Modeling: Illustrative Examples and Problems The Modeling Aspect of Simulation Single-Server, Single-Input, First-In/First-Out (FIFO) Queue Multiple-Server, Single-Input Queue An Example from Statistics: The Trimmed t Statistic An Example from Engineering: Reliability of Series Systems A Military Problem: Proportional Navigation Comments on the Examples Crude (or Straightforward) Simulation and Monte Carlo Introduction: Pseudo-Random Numbers Crude Simulation Details of Crude Simulation A Worked Example: Passage of Ships Through a Mined Channel Generation of Random Permutations Uniform Pseudo-Random Variable Generation Introduction: Properties of Pseudo-Random Variables Historical Perspectives Current Algorithms Recommendations for Generators Computational Considerations The Testing of Pseudo-Random Number Generators Conclusions on Generating and Testing Pseudo-Random Number Generators SOPHISTICATED SIMULATION Descriptions and Quantifications of Univariate Samples: Numerical Summaries Introduction Sample Moments Percentiles, the Empirical Cumulative Distribution Function, and Goodness-of-Fit Tests Quantiles Descriptions and Quantifications of Univariate Samples: Graphical Summaries Introduction Numerical and Graphical Representations of the Probability Density Function Alternative Graphical Methods for Exploring Distributions Comparisons in Multifactor Simulations: Graphical and Formal Methods Introduction Graphical and Numerical Representation of Multifactor Simulation Experiments Specific Considerations for Statistical Simulation Summary and Computing Resources Assessing Variability in Univariate Samples: Sectioning, Jackknifing, and Bootstrapping Introduction Preliminaries Assessing Variability of Sample Means and Percentiles Sectioning to Assess Variability: Arbitrary Estimates from Non-Normal Samples Bias Elimination Variance Assessment with the Complete Jackknife Variance Assessment with the Bootstrap Simulation Studies of Confidence Interval Estimation Schemes Bivariate Random Variables: Definitions, Generation, and Graphical Analysis Introduction Specification and Properties of Bivariate Random Variables Numerical and Graphical Analyses for Bivariate Data The Bivariate Inverse Probability Integral Transform Ad Hoc and Model-Based Methods for Bivariate Random Variable Generation Variance Reduction Introduction Antithetic Variates: Induced Negative Correlation Control Variables Conditional Sampling Importance Sampling Stratified Sampling

121 citations


Journal ArticleDOI
TL;DR: In this paper, boundary misorientations in an Al-1OMg-O.1Zr (wt%) alloy, thermomechanically processed by rolling at 573 K (300°C), were determined both in annealed and in superplastically deformed conditions.

119 citations


Journal ArticleDOI
TL;DR: The issues involved in the design of computationally efficient algorithms for spectral correlation estimation and the resulting impact on high-speed digital realization are addressed and related special issues are discussed.
Abstract: The issues involved in the design of computationally efficient algorithms for spectral correlation estimation and the resulting impact on high-speed digital realization are addressed. The spectral correlation analyzer is characterized as a periodically time-varying quadratic system with a kernel possessing certain gross properties. The mean and variance of the output are expressed in terms of the kernel and the spectral correlation function of the input. Three realizations are analyzed in detail. One is based on the frequency-smoothing method of cross spectral analysis. The others are variants of the time-smoothing method. For each of these realizations, an exact expression for the quadratic system kernel is given, the digital implementation is developed, and a detailed complexity analysis is presented. High-speed pipeline realizations of the algorithms are analyzed, and related special issues are discussed. Examples involving the calculation of the spectral correlation function in near-real-time for broadband communications signals are discussed. >

108 citations


Journal ArticleDOI
TL;DR: The model is used to investigate the viability of two project strategies for “curing” the 90% syndrome problem and results obtained from an analysis of a NASA software project indicate that the problem arises because of the interaction of two factors.

96 citations


Journal ArticleDOI
TL;DR: It is shown that many-body interactions are important for describing the energy- and angle-resolved distributions of neutral Rh atoms ejected from keV-ion-bombarded Rh{111}, and a specific set of parameters has been found which leads to excellent agreement with recent experimental trajectory measurements of desorbed Rh atoms.
Abstract: In this paper, we show that many-body interactions are important for describing the energy- and angle-resolved distributions of neutral Rh atoms ejected from keV-ion-bombarded Rh{111}. We compare separate classical-dynamics simulations of the sputtering process assuming either a many-body potential or a pairwise additive potential. The many-body potential is constructed using the embedded-atom method to describe equilibrium properties of the crystal, parameters from the Moliere potential to describe close encounters between energized atoms, and parameters from a Rh2 potential to aid the description of the desorption event. The most dramatic difference between the many-body potential and the pair potential is in the predicted kinetic energy distributions. The pair-potential kinetic energy distribution peaks at ∼2 eV, whereas the many-body potential predicts a broader peak at ∼4 eV, giving much better agreement with experiment. This difference between the model potentials is due to the predicted nature of the attractive interaction in the surface region through which all ejecting particles pass. Variations of the many-body-potential parameters are examined in order to ascertain their effect on the predicted energy and angular distributions. A specific set of parameters has been found which leads to excellent agreement with recent experimental trajectory measurements of desorbed Rh atoms.

94 citations


Journal ArticleDOI
TL;DR: A review of the extended surface literature from 1922 to 1987 is presented in this article, where a chronological approach is abandoned in favor of a categorization into topical areas including the elimination of the Murray-Gardner assumptions, boiling and condensation, experimental endeavors, compact heat exchangers, internally finned configurations, numerical analyses, optimizations, analyses of finned arrays, and additional topics including the use of extended surface to augment heat transfer, heat transfer in electrical and electronic equipment, purely mathematical techniques, and heat and mass transfer.
Abstract: The extended surface literature from 1922 to 1987 is reviewed. The review begins with the classic NACA report of Harper and Brown published in 1922 and concludes with the works of Marto, Wanniarachchi, Rose, Mitrou, and Razelos published in 1986. A section entitled “The Beginnings” traces the accomplishments of the pioneers and it covers the period from 1922 to 1945 which coincides with the publication of Gardner’s landmark paper. At this point, a chronological approach is abandoned in favor of a categorization into topical areas. These are the elimination of the Murray–Gardner assumptions, boiling and condensation, experimental endeavors, compact heat exchangers, internally finned configurations, numerical analyses, optimizations, analyses of finned arrays, and additional topics including the use of extended surface to augment heat transfer, heat transfer in electrical and electronic equipment, purely mathematical techniques, and heat and mass transfer.

90 citations


Book
01 Jan 1988
TL;DR: This artificial intelligence through prolog is well known book in the world, of course many people will try to own it and this is it the book that you can receive directly after purchasing.
Abstract: Why should wait for some days to get or receive the artificial intelligence through prolog book that you order? Why should you take it if you can get the faster one? You can find the same book that you order right here. This is it the book that you can receive directly after purchasing. This artificial intelligence through prolog is well known book in the world, of course many people will try to own it. Why don't you become the first? Still confused with the way?

83 citations



Journal ArticleDOI
TL;DR: The conclusion is that the IRDS is a suitable vehicle for incorporating model management and structured modeling as part of an organization's information resource management environment.
Abstract: Models have historically occupied an ambiguous position within organizations. Management acceptance of management science and operations research models for decision-making has lagged far behind technical advances in these areas. Structured modeling has emerged as a unifying approach to the modeling process with potential to reduce this ambiguity. Structured modeling is primarily oriented to the individual, however. A way of incorporating structured modeling into the organizational framework via existing information resource channels is discussed. A relational model is presented for an information resource dictionary system (IRDS). This IRDS model is then extended to accommodate representation of structured models. This extension of the IRDS can answer queries about structured modeling as well as model instances. The concept of an active IRDS is introduced and an example presented of how an active IRDS can be linked with an optimization algorithm. The conclusion is that the IRDS is a suitable vehicle for incorporating model management and structured modeling as part of an organization's information resource management environment.


Journal ArticleDOI
TL;DR: The model based Decision Support System (DSS) is designed to help choose the best supplier for each item and schedule the placement of the orders—decisions which are very difficult to make well without such a model based DSS.
Abstract: This paper describes a model based Decision Support System (DSS) for purchasing materials and components for large projects. The DSS may be used under two scenarios. Under the first scenario, we have a project to execute, and we are looking for a good way to manage the purchasing to minimize the expected costs. The decisions under our control are when and from whom to order each item. Under the other scenario, we are bidding for the project, and wish to assess the costs associated with the purchasing decisions which we should consider before making our bid. In both cases, we take into account expected out of pocket costs as well as lateness and/or expediting penalties. The DSS is designed to help choose the best supplier for each item and schedule the placement of the orders—decisions which are very difficult to make well without such a model based DSS.

Journal ArticleDOI
TL;DR: A prototyping approach that uses modularity and reusable components is described that enables large real-time systems to be prototyped rapidly and meets the following requirements: the prototype satisfies its requirements and is traceable to them.
Abstract: A prototyping approach that uses modularity and reusable components is described that enables large real-time systems to be prototyped rapidly. It combines a computational model tailored for real-time systems with a high-level prototyping language (the Prototype System Description Language), a systematic design method for rapid prototype construction, and an automated prototyping environment. The method meets the following requirements: the prototype satisfies its requirements and is traceable to them; the prototype is easy to modify; and the prototype code is easy to read and analyze. >


Journal ArticleDOI
TL;DR: An efficient heuristic algorithm based on partitioning of a traveling salesman tour that finds a solution whose cost is at most 3-2/K times the minimum; in the general case the error bound is 4.
Abstract: A tree network is a collection of trees rooted at a common central node. Several types of network design problems can be viewed as requiring the formation of a spanning tree network of minimum length, subject to a bound on the sum of "weights" on the nodes of any component tree. Such problems are NP-complete, and experience has shown that only small examples can be solved to optimality. This paper describes an efficient heuristic algorithm based on partitioning of a traveling salesman tour. When all the nodes have a unit weight and the bound is K, the heuristic finds a solution whose cost is at most 3-2/K times the minimum; in the general case the error bound is 4.

Journal ArticleDOI
TL;DR: The four Southern European democracies (Italy, Spain, Portugal and Greece) have a number of important cultural, social, economic, and historical characteristics in common, and their political systems are also often seen as similar, representing a "Mediterranean model of democracy" as mentioned in this paper.
Abstract: The four Southern European democracies ‐ Italy, Spain, Portugal and Greece ‐ have a number of important cultural, social, economic, and historical characteristics in common, and their political systems are also often seen as similar, representing a ‘Mediterranean model of democracy’. However, when these four democratic regimes are compared with the world's other democracies in terms of the contrasting majoritarian and consensus models, they turn out not to form a distinctive and cohesive cluster. The concluding section suggests several explanations for this unexpected finding.

Journal ArticleDOI
TL;DR: In this paper, the authors analyze the process of coalition in the Catalonian Parliament using Owen's modification of the Shapley value (for games with a priori unions), and show that the actual result was not unreasonable, given the underlying political structure.

Journal ArticleDOI
TL;DR: In this paper, the horizontal scale of the standing waves is determined by their vertical wavelength and the slope of the frontal surface, and these corrugations, in turn, determine the horizontal scales of the waves above the front.
Abstract: Gravity waves forced by nonhydrostatic and nongeostrophic processes within a frontal zone are discussed. In particular, stationary waves immediately above and below the surface front are considered. The waves that appear above the front are horizontally stationary with respect to the front, but are vertically propagating. The vertical wavelength here is given by 2πυ/N, since the waves are nearly hydrostatic. The horizontal wavelength of the waves above the front is determined by standing waves that set up below the Front. These waves corrugate the frontal surface, and these corrugations, in turn, determine the horizontal scale of the waves above the front. The waves under the front are standing and are trapped between the earth's surface and the frontal zone which, due to its conditions of flow reversal and small Ri, is assumed to be a reflector of gravity waves. The horizontal scale of the standing waves is determined by their vertical wavelength and the slope of the frontal surface. These waves...

Journal ArticleDOI
TL;DR: In this paper, a detailed crystallographic analysis was performed on the various combinations of martensite plate variants which meet at the boundaries formed between different self-accommodating plate groups in 18R Cu-Zn-Al martensites.

Journal ArticleDOI
TL;DR: In this paper, the formation of a mesoscale cyclone is associated with a plume of warmer potential temperature air, which originates from a ridge of higher terrain to the south of Denver, and advects northward into the area of gyre formation.
Abstract: In northeastern Colorado a frequently observed feature of the surface wind field is a stationary, terrain-induced mesoscale gyre, which is often associated with the formation of severe weather. Because of the gyre's proximity to the Denver metropolitan area, local weather forecasters frequently refer to it as the “Denver Cyclone. ” The development of one such cyclone, which occurred on 1 August 1985, is documented with mesonet, radiosonde, wind-profiler, radiometer and tower data. Mixed-layer model simulations of this event closely agree with the observed gyre structure and indicate that the gyre is associated with a plume of warmer potential temperature air, which originates from a ridge of higher terrain to the south of Denver, and advects northward into the area of gyre formation. A mixed-layer vorticity budget demonstrates that the formation of the gyre results from the baroclinic and slope effects on the turbulent stress divergence profile.

Journal ArticleDOI
TL;DR: In this paper, a set of published formulas for the frequency dependence of the microstrip effective relative dielectric constant epsilon /sub re/(f) is tested relative to an assemblage of measured data values for this quantity chosen from the literature.
Abstract: A set of published formulas for the frequency dependence of the microstrip effective relative dielectric constant epsilon /sub re/(f) is tested relative to an assemblage of measured data values for this quantity chosen from the literature. The RMS deviation of the predicted data obtained from the measured values ranged from 2.3% to 4.1% of the seven formulas for epsilon /sub re/(f) tested. A formula due to M. Kirschning and R.H. Jansen (see Electron. Lett., vol.18, p.272-73, 1982) showed the lowest average deviation from measured values, although the differences between the predictions of their formula and others tested are of the order of the error limits of the comparison process. It is concluded that the results indicate the suitability of relatively simple analytical expressions for the computation for microstrip dispersion. >

Proceedings ArticleDOI
01 Jan 1988
TL;DR: It is shown how typing supports the development of integrated models from distinct model components by defining a typing system for all the objects in a model and by specifying formal methods to manipulate the type information.
Abstract: Contemporary executable modeling languages for mathematical programming are extended by defining a typing system for all the objects in a model and by specifying formal methods to manipulate the type information. The modeler's intent to formulate consistent, meaningful constraints and functions can be automatically verified. It is shown how typing supports the development of integrated models from distinct model components. A library unit is proposed as an extension to modeling languages; it provides a mechanism for building integrated models from previously validated models. >

Proceedings ArticleDOI
06 Jun 1988
TL;DR: In this article, a viscous/inviscid interaction analysis of flow over a NACA 65-213 airfoil at a chord Reynolds number of 240,000 using a calculation method of Cebeci et al.
Abstract: Estimating the low Reynolds number and off-design performance of axial turbomachine blades requires an accurate prediction of separation phenomena occurring on the blade surface. This paper discusses a viscous/inviscid interaction analysis of flow over a NACA 65-213 airfoil at a chord Reynolds number of 240,000 using a calculation method of Cebeci et al. The computed characteristics of a mid-chord laminar separation bubble are compared with experimental laser-doppler anemometer measurements of Hoheisel et al. Attention is focused on problems of modeling the laminar-turbulent transition zone within the viscous layer.A parametric study is undertaken to determine the location and extent of the transition zone which best models the observed separation bubble behavior. The required transition length is almost an order of magnitude smaller than that predicted from conventional transition length correlations. A physical model for this greatly reduced transition length in positive pressure gradient flows is proposed.The computational model correctly predicts most features of the separation bubble flow, but there are some significant discrepancies at reattachment which point to the need for improved turbulence modeling in this area. The inclusion of transverse pressure gradients associated with flow curvature in the viscous regions also appears very desirable for airfoils operating at Reynolds numbers around 105.Copyright © 1988 by ASME

Journal ArticleDOI
TL;DR: It is shown how MLDS, by providing an integrated environment for experimenting with data models and data languages, also serves as a testbed that provides insight to data model and data-model semantics, using qualitative and quantitative techniques.
Abstract: An approach to the design of a database system, the multilingual database system (MLDS), has been proposed and implemented. MLDS is a single database system that can execute may transactions written respectively in different data languages and support many databases structured correspondingly in various data models, i.e. DL/I transactions on hierarchical databases, CODASYL-DML transactions on network databases, SQL transactions on relational databases, and Daplex transactions on functional databases. The authors describe MLDS, focusing on its motivation and structure. It is shown how MLDS, by providing an integrated environment for experimenting with data models and data languages, also serves as a testbed that provides insight to data models and data-model semantics, using qualitative and quantitative techniques. Related work on data-language comparison and analysis is indicated. >

Journal ArticleDOI
Luqi1
TL;DR: The authors discusses the computer-aided prototyping system's knowledge base and shows how to apply expert-system technology to the software base management subsystem responsible for finding reusable software components with specified properties.
Abstract: The authors discusses the computer-aided prototyping system's knowledge base and shows how to apply expert-system technology to the software base management subsystem responsible for finding reusable software components with specified properties. She uses rapid prototyping techniques to allow the detection and correlation of requirement errors early in development. The goal is to automate support for analyzing new problem domains rather than automating the generation of many similar systems in well-understood problem domains. For this reason, the author addresses a general purpose computer-aided prototyping system rather than specialized application generators. The discussion focuses on retrieval strategies, declarative knowledge, and transformations. >

Journal ArticleDOI
TL;DR: This mesoscopic scale is important, not only to achieve pattern recognition or to test the analysis of the microscopic Scale, but indeed it is to be respected as a potential source of command and control over the microscopic scale, in both the brain and other large-scale systems, e.g., in Command, Control and Communications (C^3) systems.

Journal ArticleDOI
TL;DR: The first time that such a self-consistent data set of surface conditions within a tropical cyclone has been collected was reported in this paper, where three drifting buoys were successfully air-dropped ahead of Hurricane Josephine, which resulted in detailed simultaneous measurements of surface wind speed, surface pressure and subsurface ocean temperature during and subsequent to storm passage.
Abstract: Three drifting buoys were successfully air-dropped ahead of Hurricane Josephine. This deployment resulted in detailed simultaneous measurements of surface wind speed, surface pressure and subsurface ocean temperature during and subsequent to storm passage. This represents the first time that such a self-consistent data set of surface conditions within a tropical cyclone has been collected. Subsequent NOAA research overflights of the buoys, as part of a hurricane planetary boundary-layer experiment, showed that aircraft wind speeds, extrapolated to the 20 m level, agreed to within ±2 m s−1, pressures agreed to within ±1 mb, and sea-surface temperatures agreed to within ±0.8°C of the buoy values. Ratios of buoy peak 1 min wind (sustained wind) to one-half h mean wind > 1.3 were found to coincide with eyewall and principal rainband features. Buoy trajectories and subsurface temperature measurements revealed the existence of a series of mesoscale eddies in the subtropical front. Buoy data revealed st...

Journal ArticleDOI
TL;DR: In this paper, the effects of a propeller slipstream on the wing laminar boundary layer are investigated, and it is shown that the boundary layer cycles between a Laminar state and a turbulent state at the propeller blade passage rate.
Abstract: The effects of a propeller slipstream on the wing laminar boundary layer are being investigated. Hot-wire velocity sensor measurements have been performed in flight and in a wind tunnel. It is shown that the boundary layer cycles between a laminar state and a turbulent state at the propeller blade passage rate. The cyclic length of the turbulent state increases with decreasing laminar stability. Analyses of the time varying velocity profiles show the turbulent state to lie in a transition region between fully laminar and fully turbulent. The observed cyclic boundary layer has characteristics similar to relaminarizing flow and laminar flow with external turbulence.