ppxscal/embedding_network huggingface dataset:
Analytic Method for Radiometric Correction of Satellite Multispectral Scanner Data
Authors: R. J. Woodham, M. H. Gray
Venue:  (1987)

The problem of radiometric correction of multispectral scanner data is posed as the problem of determining an intrinsic reflectance factor characteristic of the surface material being imaged and invariant to topography, position of the sun, atmosphere and position of the viewer. A scene radiance equation for remote sensing is derived based on an idealized physical model of image formation. The scene radiance equation is more complex for rugged terrain than for flat terrain since it must model slope, aspect and elevation dependent effects. Scene radiance is determined by the bidirectional reflectance distribution function (BRDF) of the surface material and the distribution of light sources. The sun is treated as a collimated source and the sky is treated as a uniform hemispherical source. The atmosphere is treated as an optically thin, horizontally uniform layer. The limits of this approach are reviewed using results obtained with Landsat MSS images and a digital terrain model (DTM) of a test site near St. Mary Lake, British Columbia, Canada. New results, based on regression analysis, are described for the St. Mary Lake site. Previous work is extended to take advantage of explicit forest cover data and to consider numeric models of sky radiance. The calculation of sky irradiance now takes occlusion by adjacent terrain into account. The results for St. Mary Lake suggest that the cosine of the incident solar angle and elevation are the two most important correction terms. Skylight and inter-reflection from adjacent terrain, however, also are significant.
S-PARAMETER BASED MACRDO MODEL OF DISTRIBUTED-LUMPED NETWORKS USING EXPONENTIALLY DECAYED POLYNOMIAL FUNCTION
Authors: Haifang Liao, Wayne W Dai, Rui Wang, Fung Chang
Venue:  (1992)

A Scattering-Parameters (S-Parameters) based macromodel of distributed-lumped networks is presented. The networks can include capacitive cutsets, inductive loops, RLC meshes, and loss transmission lines. An efficient network reduction algorithm is developed to reduce the original network into a network containing one multiport component together with the sources and loads of interest. The S-Parameters of the circuit components are approximated by Taylor series to simplify the reduction process. Exponentially Decayed Polynomial Function (EDPF) approximation is used to derive the macromodel, the higher accuracy can be obtained by selecting time constant according to an error criterion. The macromodel is always stable for a stable system and very flexible that the accuracy of the model can be controlled by adjusting the order of approximation. The experimental results indicate that our model can approach the accuracy of SPICE with one or two order less computing time.
Implementation of Team Shoshin: An Exercise in Porting and Multiprocess Structuring of the Kernel
Authors: Huay Wang
Venue:  (1986)

Team Shoshin is an extension of Shoshin, a testbed for distributed software originally developed on the LSI 11/23s at the University of Waterloo. This thesis presents a description of the implementation of Team Shoshin on the Sun Workstation. With wide disparity in the underlying hardware, a major part of our initial development effort is to port Shoshin to its new hardware. The problems and design decisions faced by the porting effort and how they are overcome will be discussed. The development of Team Shoshin has provided us the opportunity to investigate the use of multiprocess structuring techniques at the kernel level. We will describe the design and implementation of the proposed kernel multiprocess structure and the rationale behind it. The applicability of the proposed kernel multiprocess structure and its impact on operating system design will be discussed drawing from experience gained through actual implementation. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
A Call for Integrating Advanced Information Retrieval Models with CD-ROM/Microcomputer Systems
Authors: Edward A. Fox
Venue:  (1986)

Recent advances in computer hardware and storage devices will allow inexpensive personal systems to be used by individuals to rapidly access vast collections of text. Research into database management, artificial intelligence, and information retrieval can all be applied to develop advanced retrieval systems. Retrieval models based on browsing, extended Boolean, vector, probabilistic, and artificial intelligence approaches have all been advanced as more effective for searchers than conventional methods. The CODER project aims to integrate these techniques. Ultimately it is hoped that CD-ROM based information retrieval systems will be released with many of the capabilities mentioned.
SCALABLE PARALLEL DIRECT VOLUME RENDERING FOR NONRECTILINEAR COMPUTATIONAL GRIDS (Ph.D. Thesis)
Authors: Judith Challinger
Venue:  (1993)

Various approaches to the problem of parallelizing direct volume rendering algorithms are discussed, and a scalable approach to parallel direct volume rendering of nonrectilinear computational grids is presented. The algorithm is general enough to handle non-convex grids and cells, grids with voids, grids constructed from multiple grids (multi-block grids), and embedded geometrical primitives. The algorithm is designed for a highly parallel MIMD architecture which features both local memory and shared memory with non-uniform memory access times. It has beem implemented on a BBN TC2000 and benchmarked on several datasets. An analysis of the speedup and efficiency of the algorithm is given and any sources of inefficiency are indentified. The trade-off between load balancing requirements and the loss of coherence due to the image-space task decomposition is examined. A variation of the algorithm which provides fast image updated for a changing transfer function is also presented. A distributed approach to controlling the execution of the volume render is used and the graphical user interface designed for this purpose is briefly described.
Simulation Model Specifications: On the Role of Representation in theModel-Centered Sciences
Authors: Ernest H. Page, Richard E. Nance
Venue:  (1994)

The old adage that "a problem correctly formulated is half solved" is rarely challenged. Model-centered problem solving relies critically on a correct model. Complete, clearly stated assumptions, a precise statement of objectives, and an adequate representation of the model of the system under study are readily accepted as responsibilities of the modeler. But just how important are both the process and product of model representation? The modeler''s responsibilities in producing a correct model can be either significantly aided or drastically inhibited by the representational mechanism - the language - being used. The comprehensibility of the model, subsequent extension, adaptation, or maintenance of the model, are highly dependent on the representational language. Language for model representation is therefore an indispensible tool. The pivotal role of this tool is described through its relationship to modeling methodology, model development environments, and automated model diagnosis. The need for an emphasis on the capabilities for conceptual expressiveness, in contrast with execution efficiency is discussed. While software engineering research clearly advocates this redefinition of emphasis, we observe that much of the research in the rising disciplines within parallel computation appears to ignore the lessons of this history.
The Application of Optimal Stochastic Control Theory in Computer System Load Regulation
Authors: Samuel T. Chanson, Raymond Lo
Venue:  (1981)

A method using some results and techniques of Optimal Stochastic Control Theory is introduced to compute the optimal admission policy for paged batch-interactive computer systems. The admission policy determines the optimal number of batch and terminal jobs that should be activated at each system state to maximize throughput. The system state is defined as the vector (N1,N2) where N1 and N2 are respectively the total number of terminal and batch jobs in the system. Thus the policy is adaptive to workload variation. As well, the quality of service given to each class of jobs (specifically their mean response times) can be adjusted by choosing a suitable weight for the terminal jobs. A large weight reduces the mean response time of the terminal jobs at the expense of the mean batch response time while maintaining the total system throughput at its maximum level. .br Unlike most existing adaptive control algorithms, the approach is based on mathematical modelling and its extension to cover the case of more than two classes of jobs is straightforward.
The computational power of cell division in P systems: Beating down parallel computers?
Authors: Petr Sosík
Venue: Natural Computing: an international journal (2003)

We study the computational power of cell division operations in the formal framework of P systems, a mathematical model of cell-like membrane structure with regulated transport of objects (molecules) through membranes. We show that a uniform family of P systems with active membranes and 2-division is able to solve the well-known PSPACE-complete problem QBF in linear time. This result implies that such a family of P systems modelling cell division is at least as powerful as so-called Second Machine Class computers. The Second Machine Class, containing most of the fundamental parallel computer models such as parallel RAM machines of types SIMD and MIMD, vector machines and others, is characterized by using an exponential amount of resources (processing units) with respect to the computing time.
Problems on Pairs of Trees and the Four Colour Problem of Planar Graphs
Authors: Artur Czumaj, A. M. Gibbons
Venue:  (1993)

In 1977, Appel and Haken proved that every planar graph is four vertex colourable. Their proof is very long and the implicit algorithm for four colouring is rather impractical. This paper provides a new characterisation of the four colour problem by showing that it is equivalent, by a very fast reduction, to a simply stated problem of 3-edge colouring pairs of trees. This new problem, in turn, is equivalent to non-trivial subclasses of other problems in mathematics and computer science of which we describe three. These are problems of intersection of regular languages of integer linear equations and of algebraic expressions. In the general case, all these problems require exponential time to find a solution. We show that if these problems are defined on pairs of trees, then polynomial time is sufficient. In addition, these problems offer enticing opportunities in the search for a shorter proof of the four colour theorem and for more practical algorithms for four colouring planar graphs.
Pamma Noniterative Approximate Solution Method for Closed MultichainQueueing Networks
Authors: Ching Hsieh, Simon S. Lam
Venue:  (1987)

Approximate MVA algorithms for separable queueing networks are based upon an iterative solution of a set of modified MVA formulas. Although each iteration has a computational time requirement of or less, many iterations are typically needed for convergence to a solution. (M denotes the number of queues and K the number of closed chains or customer classes.) They are suitable for the analysis and design of communication networks which may require tens to hundreds, perhaps thousands, of closed chains to model flow- controlled virtual channels. The basis of our method is the distribution of a chain''s population proportional to loads to get initial estimates of mean queue lengths. This is the same basis used in the derivation of proportional upper bounds for single- chain networks; for a multichain network, such a proportional distribution leads to approximations rather than upper bounds of chain throughputs. Nevertheless, these approximate solutions provide chain throughputs, mean end-to-end delays, and server utilizations that are sufficiently accurate for the analysis and design of communication networks and possibly other distributed systems with a large number of customer classes. Three PAM algorithms of increasing accuracy are presented.
Topological Aspects of Regular Languages
Authors: Nicholas Pippenger
Venue:  (1994)

We establish a number of new results (and rederive some old results) concerning regular languages, using essentially topological methods. Our development is based on the duality (established by Stone) between Boolean algebras and certain topological spaces (which are now called "Stone spaces"). (This duality does not seem to have been recognized in the literature on regular languages, even though it is well known that the regular languages over a fixed alphabet form a Boolean algebra and that the "implicit operations" with a fixed number of operands form a Stone space!) By exploiting this duality, we are able to obtain a much more accessible account of the Galois correspondence between varieties of regular languages (in the sense of Eilenberg) and certain sets of "implicit identities". The new results include an analogous Galois correspondence for a generalization of varieties, and an explicit characterization by means of closure conditions of the sets of implicit identities involved in these correspondences.
Computation Paths Logic: An Expressive, Yet Elementary, Process Logic
Authors: D. Harel, E. Singerman
Venue:  (1997)

A new process logic is defined, called computation paths logic (CPL), which treats formulas and programs essentially alike. CPL is a pathwise extension of PDL, following the basic process logic of Harel, Kozen and Parikh, and is close in spirit to the logic R of Harel and Peleg. It enjoys most of the advantages of previous process logics, yet is decidable in elementary time. We also offer extensions for modeling asynchronous/synchronous concurrency and infinite computations. All extensions are also shown to be decidable in elementary time.
Reasoning about Hybrid Reasoning: a Discussion
Authors: Ian P. Gent, A. G. Cohn
Venue:  (1991)

In this discussion we outline an approach to reasoning about hybrid reasoning systems. We believe that following this approach allows theoretical results to be obtained rapidly, allows a high level of understanding about the relationship between different hybrid reasoning systems, and allows advantage to be taken of results about classical systems. There are two aspects to the approach we propose. First, we suggest that we should treat hybrid reasoning systems in as much generality as possible. Second, although we acknowledge that unification is of central importance in hybrid reasoning systems, we think it can be a mistake to centre theoretical treatments of hybrid reasoning systems on unification itself. Instead we suggest that one should consider proof systems without unification and then introduce unification as a purely syntactic measure to improve efficiency.
VizCraft: A Problem Solving Environment for Configuration Design of High Speed Civil Transport
Authors: Goel A., Baker C.A., Shaffer C.A., Grossman B., Mason W.H., Watson L.T., Haftka R.T.
Venue:  (1999)

We describe a problem solving environment (PSE) named VizCraft that aids aircraft designers during the conceptual design stage. At this stage,an aircraft design is defined by a vector of 10-30 parameters. The goal is to find a vector that minimizes a performance-based objective function while meeting a series of constraints. VizCraft integrates the simulation code that evaluates a design with visualization for analyzing a design individually or in contrast to other designs. VizCraft allows the designer to easily switch between the view of a design in the form of a parameter set, and a visualization of the corresponding aircraft geometry. The user can easily see which, if any, constraints are violated. VizCraft also allows the user to view a database of designs using parallel coordinates. Keywords: Problem solving environment,scientific data visualization, mutlidiimensional visualization, aircraft design, multidisciplinary design optimization.
Dataflow Java: Implicitly Parallel Java
Authors: Gareth Lee, John Morris
Venue:  (1999)

Abstract unavailable.
Shallow Multiplication Circuits and Wise Financial Investments
Authors: M. S. Paterson, U. Zwick
Venue:  (1992)

Paterson, Pippenger and Zwick have recently obtained a general theory that describes the optimal way in which given carry-save adders can be combined into carry-save networks. Their work produces, in particular, multiplication circuits of depth 3.71 log* n (these circuits put out two numbers whose sum is the result of the multiplication). In this work an extension of the above general theory is obtained. We now consider carry-save adders that may receive inputs and produce outputs using several different representation methods. We describe the optimal way of utilising any such collection of carry-save adders. The optimality proof uses the min-max theorem of game theory. By using several different representation standards, the depth of multiplication circuits can be surprisingly reduced to 3.48 log* n (again two output numbers are produced). We introduce bit level redundancy by using a novel coding scheme in which each bit is distributed over four wires. Interestingly, the information on these four wires is usually not transmitted simultaneously. Finally, an analogy is made between the optimisation problem faced by the circuit designer and the optimisation problem faced by an investor, offered a collection of financial investment plans, each involving perhaps several different currencies. This analogy is used to obtain intuitive explanations of the results obtained.
Animation of Fish Swimming
Authors: William F. Gates
Venue:  (2002)

We present a simple, two-part model of the locomotion of slender-bodied aquatic animals designed specifically for the needs of computer animation. The first part of the model is kinematic and addresses body deformations for three swimming modes: steady swimming, rapid starting, and turning. The second part of the model is dynamic and addresses the resulting propulsion of the aquatic animal. While this approach is not as general as a fully dynamic model, it provides the animator with a small set of intuitive parameters that directly control how the fish model moves and is more efficient to simulate.
Seeing Things Your Way: Information Visualization for a User-Centered Database of Computer Science Literature
Authors: Lucy T Nowell, Edward A. Fox, Lenwood S. Heath, Deborah Hix, William C. Wake, Eric D. Labow
Venue:  (1994)

Project Envision is a user-centered multimedia database of computer science literature. Envision features powerful information visualization by displaying search results as a matrix of icons, with layout semantics under user control. Its Graphic View interacts with Item Summary and Preview Item windows to give users access to bibliographic information and abstracts. The concepts underlying these windows are being extended to a Graphical Browser for the full database and for hierarchical structures. This paper describes the development process and information visualization facilities in Envision search results and browsing displays.
Control-Theoretic Techniques and Thermal-RC Modeling for Accurate and Localized Dynamic Thermal Management
Authors: Kevin Skadron, Tarek Abdelzaher, Mircea R. Stan
Venue:  (2001)

This paper proposes the use of formal feedback control theory as a way to implement adaptive techniques in the processor architecture. Dynamic thermal management (DTM) is used as a test vehicle, and variations of a PID controller (Proportional-Integral-Differential) are developed and tested for adaptive control of fetch "toggling." To accurately test the DTM mechanism being proposed, this paper also develops a thermal model based on lumped thermal resistances and thermal capacitances. This model is computationally efficient and tracks temperature at the granularity of individual functional blocks within the processor. Because localized heating occurs much faster than chip-wide heating, some parts of the processor are more likely to be "hot spots" than others. Experiments using Wattch and the SPEC2000 benchmarks show that the thermal trigger threshold can be set within 0.2 degrees of the maximum temperature and yet never enter thermal emergency. This cuts the performance loss of DTM by 65% compared to the previously described fetch toggling technique that uses a response of fixed magnitude.
Performance Measures for Constrained Systems
Authors: Kees van den Doel, Dinesh K. Pai
Venue:  (1995)

We present a geometric theory of the performance of robot manipulators, applicable to systems with constraints, which may be non-holonomic. The performance is quantified by a geometrical object, the induced metric tensor, from which scalars may be constructed by invariant tensor operations to give performance measures. The measures thus defined depend on the metric structure of configuration and work space, which should be chosen appropriately for the problem at hand. The generality of this approach allows us to specify a system of joint connected rigid bodies with a large class of metrics. We describe how the induced metric can be computed for such a system of joint connected rigid bodies and describe a MATLAB program that allows the automatic computation of the performance measures for such systems. We illustrate these ideas with some computations of measures for the SARCOS dextrous arm, and the Platonic Beast, a multi-legged walking machine.
Pasting Spline Surfaces
Authors: C. Banghiel, Richard H. Bartels, David R. Forsey
Venue:  (1995)

Details can be added to spline surfaces by applying displacement maps. However, the computational intensity of displacement mapping prevents its useful for interactive design. In this paper we explore a form of simulated displacement that can be used for interactive design by providing a preview of true displacements at low computational cost.
Cooperative Modeling in Applied Geographic Research
Authors: Gustavo Alonso, Amr El Abbadi
Venue:  (1994)

The characteristics of geographic data and the nature of geographic research require the participation of many agents. Data is generated by multiple sources (satellites, ground observation, weather stations, photography, etc.), accessed, processed and transformed by many users and available for use to an even larger population of users. Lack of coordination among all these different agents may render large amounts of work useless. Most existing GIS (Geographic Information Systems) do not provide any support for cooperative work, which adds to the problem. To overcome this serious limitation while still allowing users to take advantage of GIS technology, we propose GOOSE, a system implemented as a top layer for existing GIS. GOOSE provides the tools for constructing large geographic models in a cooperative environment with potentially many users and participants.