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Articles 1771 - 1800 of 1943

Full-Text Articles in Engineering

Towards Automatic Detection Of Erroneous Measurement Results In A Gravity Database, Qian Wen, Ann Q. Gates, Jan Beck, Vladik Kreinovich, George R. Keller Jun 2001

Towards Automatic Detection Of Erroneous Measurement Results In A Gravity Database, Qian Wen, Ann Q. Gates, Jan Beck, Vladik Kreinovich, George R. Keller

Departmental Technical Reports (CS)

Geospatial databases often contain erroneous measurements. For some such databases such as gravity databases, the known methods of detecting erroneous measurements -- based on regression analysis -- do not work well. As a result, to clean such databases, experts use manual methods which are very time-consuming. In this paper, we propose a (natural) "localized" version of regression analysis as a technique for automatic cleaning. We illustrate the efficiency of this technique on the example of the gravity database.


Localized Regression Analysis As A Method For Detecting Erroneous Measurements In Geospatial Databases, With Application To Gravity Databases, Qian Wen, Nigel Hicks, George R. Keller, Ann Q. Gates, Vladik Kreinovich Jun 2001

Localized Regression Analysis As A Method For Detecting Erroneous Measurements In Geospatial Databases, With Application To Gravity Databases, Qian Wen, Nigel Hicks, George R. Keller, Ann Q. Gates, Vladik Kreinovich

Departmental Technical Reports (CS)

Geospatial databases generally consist of measurements related to points (or pixels in the case of raster data), lines, and polygons. In recent years, the size and complexity of these databases have increased significantly and they often contain erroneous measurements or noise. In this paper, we address the problem of detecting erroneous and suspicious values in a database consisting of point measurements. We use a database of measurements of anomalies in the Earth's gravity field that we have complied as a test case, and we found that the standard methods of detecting erroneous measurements - based on regression analysis - do …


2-D Analogues Of Allen Interval Algebra For Image Analysis: Towards Justification, Scott A. Starks, Dima Iourinski, Vladik Kreinovich Jun 2001

2-D Analogues Of Allen Interval Algebra For Image Analysis: Towards Justification, Scott A. Starks, Dima Iourinski, Vladik Kreinovich

Departmental Technical Reports (CS)

In reasoning about time and duration, researchers often use Allen's Interval Algebra. This algebra describes possible relations between 1-D intervals. An interval can precede the other one, follow the other one, start the other one, etc. This algebra describes the relationship between different intervals in terms of words from natural language. To give a natural language description of 2D images, it is desirable to develop a similar approach for describing the relationship between 2-D objects in a picture. In their recent papers, Jim Keller and his collaborators proposed a new approach based on a simulation of a ``force" between these …


Reduction To Independent Variables: From Normal Distribution To General Statistical Case To Fuzzy, Mourad Oussalah, Hung T. Nguyen, Vladik Kreinovich Jun 2001

Reduction To Independent Variables: From Normal Distribution To General Statistical Case To Fuzzy, Mourad Oussalah, Hung T. Nguyen, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical problems, we must combine ("fuse") data represented in different formats, e.g., statistical, fuzzy, etc. The simpler the data, the easier to combine them. Therefore, to combine complex data, it is desirable to "decompose" this complex data into simpler (easy-to-combine) data chunks.

It is well known that when we have n random variables x1, ..., xn with a joint Gaussian distribution, then we can reduce them to n independent variables by an appropriate linear transformation x1, ..., xn --> y1 = f1(x1,...,xn), ..., yn = fn(x1,...,xn). It is not so well known but also true that when we …


Automatic Referencing Of Satellite And Radar Images, Sreenath Srikrishnan, Roberto Araiza, Hongjie Xie, Scott A. Starks, Vladik Kreinovich Jun 2001

Automatic Referencing Of Satellite And Radar Images, Sreenath Srikrishnan, Roberto Araiza, Hongjie Xie, Scott A. Starks, Vladik Kreinovich

Departmental Technical Reports (CS)

In order to adequately process satellite and radar information, it is necessary to find the exact correspondence between different types of images and between these images and the existing maps. In other words, we need to reference these images. In this paper, we propose new methods for automatic referencing of satellite and radar images.


Towards More Realistic (E.G., Non-Associative) And- And Or-Operations In Fuzzy Logic, Jesus Martinez, Leopoldo Macias, Ammar Esper, Jesus Chaparro, Vick Alvarado, Scott A. Starks, Vladik Kreinovich Jun 2001

Towards More Realistic (E.G., Non-Associative) And- And Or-Operations In Fuzzy Logic, Jesus Martinez, Leopoldo Macias, Ammar Esper, Jesus Chaparro, Vick Alvarado, Scott A. Starks, Vladik Kreinovich

Departmental Technical Reports (CS)

How is fuzzy logic usually formalized? There are many seemingly reasonable requirements that a logic should satisfy: e.g., since A&B and B&A are the same, the corresponding and-operation should be commutative. Similarly, since A&A means the same as A, we should expect that the and-operation should also satisfy this property, etc. It turns out to be impossible to satisfy all these seemingly natural requirements, so usually, some requirements are picked as absolutely true (like commutativity or associativity), and others are ignored if they contradict to the picked ones. This idea leads to a neat mathematical theory, but the analysis of …


Can Computers Do The Job Of Nobelist Physicists? Planck Formula Revisited, Richard Alo, Raul Trejo, Vladik Kreinovich May 2001

Can Computers Do The Job Of Nobelist Physicists? Planck Formula Revisited, Richard Alo, Raul Trejo, Vladik Kreinovich

Departmental Technical Reports (CS)

There exist several computer programs which successfully model the discovery process in science. There are successful expert systems in medicine and other areas. But one area is a real challenge for such systems: theoretical physics. The most advanced knowledge discovery programs (like BACON written under the supervision of the Nobelist Herbert A. Simon) successfully reproduce only 17, 18, and 19 century physics, but stop short of explaining the very first formula of the 20 century: Planck's law of black body radiation. This law, discovered by an insight, led to the modern Quantum Physics. The programs stop short not because the …


Assessing The Predictive Accuracy Of Complex Simulation Models, Timothy Ross, Vladik Kreinovich, Cliff Joslyn May 2001

Assessing The Predictive Accuracy Of Complex Simulation Models, Timothy Ross, Vladik Kreinovich, Cliff Joslyn

Departmental Technical Reports (CS)

No abstract provided.


Computational Complexity Of Planning With Temporal Goals, Chitta Baral, Vladik Kreinovich, Raul A. Trejo Apr 2001

Computational Complexity Of Planning With Temporal Goals, Chitta Baral, Vladik Kreinovich, Raul A. Trejo

Departmental Technical Reports (CS)

In the last decade, there has been several studies on the computational complexity of planning. These studies normally assume that the goal of planning is to make a certain fluent true after the sequence of actions. In many real-life planning problems, the goal is represented in a much more complicated temporal form: e.g., in addition to having a desired fluent true at the end, we may want to keep certain fluents true at all times. In this paper, we study the complexity of planning for such temporal goals. We show that for goals expressible in Linear Temporal Logic, planning has …


Which Truth Values In Fuzzy Logics Are Definable?, Hung T. Nguyen, Vladik Kreinovich, Antonio Di Nola Apr 2001

Which Truth Values In Fuzzy Logics Are Definable?, Hung T. Nguyen, Vladik Kreinovich, Antonio Di Nola

Departmental Technical Reports (CS)

In fuzzy logic, every word or phrase describing uncertainty is represented by a real number from the interval [0,1]. There are only denumerable many words and phrases, and continuum many real numbers; thus, not every real number corresponds to some commonsense degree of uncertainty. In this paper, for several fuzzy logic, we describe which numbers are describing such degrees, i.e., in mathematical terms, which real numbers are definable in the corresponding fuzzy logic.


An Even More Realistic (Non-Associative) Interval Logic And Its Relation To Psychology Of Human Reasoning, I. R. Goodman, Raul Trejo, Vladik Kreinovich, Jesus Martinez, Reginaldo Gonzalez Mar 2001

An Even More Realistic (Non-Associative) Interval Logic And Its Relation To Psychology Of Human Reasoning, I. R. Goodman, Raul Trejo, Vladik Kreinovich, Jesus Martinez, Reginaldo Gonzalez

Departmental Technical Reports (CS)

No abstract provided.


Interval Computations As A Particular Case Of A General Scheme Involving Classes Of Probability Distributions, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Harry Schulte Mar 2001

Interval Computations As A Particular Case Of A General Scheme Involving Classes Of Probability Distributions, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Harry Schulte

Departmental Technical Reports (CS)

Traditionally, in science and engineering, measurement uncertainty is characterized by a probability distribution; however, we don't know this probability distribution exactly, so we must consider classes of probability distributions. Interval computations deal with a very specific type of such classes: classes of all distributions which are located on a given interval. We show that in general, we need all convex classes of probability distributions.


Why Unary And Binary Operations In Logic: General Result Motivated By Interval-Valued Logics, Hung T. Nguyen, Vladik Kreinovich, I. R. Goodman Mar 2001

Why Unary And Binary Operations In Logic: General Result Motivated By Interval-Valued Logics, Hung T. Nguyen, Vladik Kreinovich, I. R. Goodman

Departmental Technical Reports (CS)

Traditionally, in logic, only unary and binary operations are used as basic ones - e.g., "not", "and", "or" - while the only ternary (and higher order) operations are the operations which come from a combination of unary and binary ones. For the classical logic, with the binary set of truth values {0,1}, the possibility to express an arbitrary operation in terms of unary and binary ones is well known: it follows, e.g., from the well known possibility to express an arbitrary operation in DNF form. A similar representation result for [0,1]-based logic was proven in our previous paper. In this …


How To Make Sure That "~100" + 1 Is ~100 In Fuzzy Arithmetic: Solution And Its (Inevitable) Drawbacks, Vladik Kreinovich, Hung T. Nguyen, Witold Pedrycz Mar 2001

How To Make Sure That "~100" + 1 Is ~100 In Fuzzy Arithmetic: Solution And Its (Inevitable) Drawbacks, Vladik Kreinovich, Hung T. Nguyen, Witold Pedrycz

Departmental Technical Reports (CS)

From the commonsense viewpoint, if a person who weighs around 100 kilograms gains one more kilogram, his weight is still around 100 kilograms. Alas, not so in traditional fuzzy arithmetic. In this paper, we propose a modification of fuzzy arithmetic which does have this property. We gain the desired property, but there is no free lunch, we have to lose two important properties of the traditional fuzzy arithmetic: first, addition is no longer always associative; second, addition is no longer always easily computable.


1st Order, 2nd Order, What Next? Do We Really Need Third-Order Descriptions: A View From A Realistic (Granular) Viewpoint, Vladik Kreinovich, Hung T. Nguyen Mar 2001

1st Order, 2nd Order, What Next? Do We Really Need Third-Order Descriptions: A View From A Realistic (Granular) Viewpoint, Vladik Kreinovich, Hung T. Nguyen

Departmental Technical Reports (CS)

To describe experts' uncertainty in a knowledge-based system, we usually use numbers from the interval [0,1] (subjective probabilities, degrees of certainty, etc.). The most direct way to get these numbers is to ask the expert; however, the expert may not be 100\% certain what exactly number describes his uncertainty; so, we end up with a second-order uncertainty - a degree of certainty describing to what extent a given number d adequately describes the expert's uncertainty about a given statement A. At first glance, it looks like we should not stop at this second order: the expert is probably as uncertain …


Computing The Shape Of The Image Of A Multi-Linear Mapping Is Possible But Computationally Intractable: Theorems, Raul A. Trejo, Vladik Kreinovich Mar 2001

Computing The Shape Of The Image Of A Multi-Linear Mapping Is Possible But Computationally Intractable: Theorems, Raul A. Trejo, Vladik Kreinovich

Departmental Technical Reports (CS)

In systems without inertia (or with negligible inertia), a change in the values of control variables x1,...,xn leads to the immediate change in the state z of the system. In more precise terms, for such systems, every component zi of the state vector z=(z1,...,zd) is a function of the control variables. When we know what state z we want to achieve, the natural question is: can we achieve this state, i.e., are there values of the control variables which lead to this very state?

The simplest possible functional dependence is described by linear functions. For such functions, the question of …


On Fusion Of Soft And Hard Computing: Traditional ("Hard Computing") Optimal Rescaling Techniques Simplify Fuzzy Control, Hugh F. Vanlandingham, Vladik Kreinovich Feb 2001

On Fusion Of Soft And Hard Computing: Traditional ("Hard Computing") Optimal Rescaling Techniques Simplify Fuzzy Control, Hugh F. Vanlandingham, Vladik Kreinovich

Departmental Technical Reports (CS)

One of the main objectives of fuzzy control is to translate expert rules - formulated in imprecise ("fuzzy") words from natural language - into a precise control strategy. This translation is usually done is two steps. First, we apply a fuzzy control methodology to get a rough approximation to the expert's control strategy, and then we tune the resulting fuzzy control system. The first step (getting a rough approximation) is well-analyzed, and the fact that we have expert's intuitive understanding enables us to use soft computing techniques to perform this step. The second (tuning) step is much more difficult: we …


What Is The Best Way To Draw A Cube? A Hypercube?, Brian D'Auriol, Vladik Kreinovich, Bindu George, Florence Muganda, Pramod Kumar Chikkpaiah Feb 2001

What Is The Best Way To Draw A Cube? A Hypercube?, Brian D'Auriol, Vladik Kreinovich, Bindu George, Florence Muganda, Pramod Kumar Chikkpaiah

Departmental Technical Reports (CS)

One of the possible connections between processors is a hypercube. The simplest case of a hypercube - a 4-vertex square - can be naturally represented on a 2-D page. To represent a 3-dimensional (or higher-dimensional) hypercube, we must project additional dimensions onto a 2-D page. In general, when we project a multi-D space into a 2-D plane, different points project into the same one. To get the best visualization, we must select a projection in such a way that the projections of different points are as distant from each other as possible. In this paper, we formalize and solve the …


The Prospect For Answer Sets Computation By A Genetic Model, A. Bertoni, G. Grossi, A. Provetti, Vladik Kreinovich, L. Tari Jan 2001

The Prospect For Answer Sets Computation By A Genetic Model, A. Bertoni, G. Grossi, A. Provetti, Vladik Kreinovich, L. Tari

Departmental Technical Reports (CS)

We combine recent results from both Logic Programming and Genetic Algorithms to design a new method for the efficent computation of Answer Sets of logic programs. First of all the problem is reduced to the problem of finding a suitable coloring on directed graphs. Then the problem of finding a suitable coloring is relaxed to a combinatorial optimization problem and solved (in an approximate way) by a continuous discrete time system derived by a genetic model.


"Conversational" Dialogues In Direct-Manipulation Interfaces, David G. Novick Jan 2001

"Conversational" Dialogues In Direct-Manipulation Interfaces, David G. Novick

Departmental Papers (CS)

This paper reports ongoing research in extending direct-manipulation interfaces by incorporating, via the direct-manipulation modality itself, interaction techniques that add kinds of language features associated with spoken conversation. The paper proposes means of implementing ways for a user of a direct-manipulation system to define new kinds of relations among objects in the interface.


Users And Uses Of Synchronous Business Communications Software, David G. Novick, Eleanor Wynn Jan 2001

Users And Uses Of Synchronous Business Communications Software, David G. Novick, Eleanor Wynn

Departmental Papers (CS)

To help designers and authors understand users' intentions and work practices for synchronous business communications in a systematic way, we used ethnographic and task-analytic techniques to collect, analyze and classify evidence of the activities of potential users as they conducted their work lives. The interactions we observed among our users took place through a variety of modalities. We found eight categories of tasks for the collaborative or interactive work in which our subjects engaged. Based on these data, we were able to classify roles of potential users of synchronous business communications software into a set of "archetypes" that characterize their …


Accounting For Domain Context In Evaluation, Meriem Chater, David G. Novick Jan 2001

Accounting For Domain Context In Evaluation, Meriem Chater, David G. Novick

Departmental Papers (CS)

Work is situated activity. Taking into account human factors in evaluation involves considering not only users but also their contexts of use. Consequently, the evaluation of systems — from video-games to safetycritical interfaces — requires analysis of context to understand not only the effect of context on usability but also the impact of artifacts' usability on users' environments. In the case of safety-critical systems (SCS), errors (by users or designers) may threaten human lives.
To assess the degree to which interface evaluation methods currently account for context, we have used the research strategy taxonomy of McGrath as a framework for …


Itanium's New Basic Operation Of Fused Multiply-Add: Theoretical Explanation And Theoretical Challenge, Vladik Kreinovich Dec 2000

Itanium's New Basic Operation Of Fused Multiply-Add: Theoretical Explanation And Theoretical Challenge, Vladik Kreinovich

Departmental Technical Reports (CS)

A new Intel's 64-bit chip Itanium has a new instruction set which includes a fused multiply-add instruction x1+x2*x3. In this short article, we explain the empirical reasons behind the choice of this instruction, give possible theoretical explanation for this choice, and mention a related theoretical challenge.


Strassen's Algorithm Made (Somewhat) More Natural: A Pedagogical Remark, Ann Q. Gates, Vladik Kreinovich Nov 2000

Strassen's Algorithm Made (Somewhat) More Natural: A Pedagogical Remark, Ann Q. Gates, Vladik Kreinovich

Departmental Technical Reports (CS)

Strassen's 1969 algorithm for fast matrix multiplication is based on the possibility to multiply two 2 x 2 matrices A and B by using 7 multiplications instead of the usual 8. The corresponding formulas are an important part of any algorithms course, but, unfortunately, even in the best textbook expositions. they look very ad hoc. In this paper, we show that the use of natural symmetries can make these formulas more natural.


Geombinatorics Of "Smart Dust", Edward Vidal, Luc Longpre, Vladik Kreinovich, Huang Haitao Oct 2000

Geombinatorics Of "Smart Dust", Edward Vidal, Luc Longpre, Vladik Kreinovich, Huang Haitao

Departmental Technical Reports (CS)

Smart Dust is a collection of small sensor-equipped leaves which send their information to two or more receivers. When a receiver gets a signal from a sensor, it can determine the direction from which this signal came. By combining the directions from two different receivers, we can determine the 3-D locations of all the leaves, and thus, transform their sensor readings into a 3-D picture of the corresponding parameters (temperature, moisture, etc.). The more leaves we send, the more information we gather. However, since the direction can only be measured with a certain accuracy, when we send too many leaves, …


Aerospace Applications Of Soft Computing And Interval Computations (With An Emphasis On Simulation And Modeling), Scott A. Starks, Vladik Kreinovich Oct 2000

Aerospace Applications Of Soft Computing And Interval Computations (With An Emphasis On Simulation And Modeling), Scott A. Starks, Vladik Kreinovich

Departmental Technical Reports (CS)

This paper presents a brief overview of our research in applications of soft computing and interval computations to aerospace problems, with a special emphasis on simulation and modeling.


On Approximation Of Fuzzy Sets By Crisp Sets: From Continuous Control-Oriented Defuzzification To Discrete Decision Making, Hung T. Nguyen, Witold Pedrycz, Vladik Kreinovich Sep 2000

On Approximation Of Fuzzy Sets By Crisp Sets: From Continuous Control-Oriented Defuzzification To Discrete Decision Making, Hung T. Nguyen, Witold Pedrycz, Vladik Kreinovich

Departmental Technical Reports (CS)

In this paper, we show that the necessity to make crisp decisions in uncertain (fuzzy) situations leads to the necessity to "approximate" fuzzy sets by crisp sets. We show that seemingly natural approximation ideas - such as using alpha-cut for a given alpha - often do not work, and we describe new approximations which not only work, but which are optimal in some reasonable sense


Optimal Elimination Of Inconsistency In Expert Knowledge: Formulation Of The Problem, Fast Algorithms, Timothy J. Ross, Berlin Wu, Vladik Kreinovich Sep 2000

Optimal Elimination Of Inconsistency In Expert Knowledge: Formulation Of The Problem, Fast Algorithms, Timothy J. Ross, Berlin Wu, Vladik Kreinovich

Departmental Technical Reports (CS)

Expert knowledge is sometimes inconsistent. In this paper, we describe the problem of eliminating this inconsistency as an optimization problem, and present fast algorithms for solving this problem.


On The Optimal Choice Of Quality Metric In Image Compression A Soft Computing Approach, Hung T. Nguyen, Olga Kosheleva, Vladik Kreinovich, Liya Ding Aug 2000

On The Optimal Choice Of Quality Metric In Image Compression A Soft Computing Approach, Hung T. Nguyen, Olga Kosheleva, Vladik Kreinovich, Liya Ding

Departmental Technical Reports (CS)

In a lossy compression, the reconstructed image I' differs from the original image I. In different situations, different compressions lead to different quality reconstruction, so it is important to select, in each situation, the best compression method. It's natural to select the compression method for which the average value of some quality metric d(I,I') is the smallest. Which quality metric should we choose? We show that under reasonable symmetry conditions, L^p metrics d(I,I')=integral of |I(x)-I'(x)|^p are the best, and how to compute the optimal value of p from the expected relative size of the informative part of the image.


Fuzzy Logic And Its Applications In Medicine, Nguyen Hoang Phuong, Vladik Kreinovich Aug 2000

Fuzzy Logic And Its Applications In Medicine, Nguyen Hoang Phuong, Vladik Kreinovich

Departmental Technical Reports (CS)

Fuzzy set theory and fuzzy logic are a highly suitable and applicable basis for developing knowledge-based systems in medicine for tasks such as the interpretation of sets of medical findings, syndrome differentiation in Eastern medicine, diagnosis of diseases in Western medicine, mixed diagnosis of Integrated western and Eastern medicine, the optimal selection of medical treatments integrating western and eastern medicine, and for real-time monitoring of patient data etc. This was verified by trials with the following systems which were developed by our group in Vietnam: a fuzzy Expert System for Syndromes Differentiation in Oriental Traditional Medicine, an Expert System for …