- Détails du magazine
- Format
- Magazine
- eISSN
- 1314-4081
- ISSN
- 1311-9702
- Première publication
- 13 Mar 2012
- Période de publication
- 4 fois par an
- Langues
- Anglais

#### Chercher

- Accès libre

Experimental Study of Lyapunov Equation Solution Bounds for Power Systems Models

Pages: 3 - 12

#### Résumé

This research work investigates the applicability of some lower and upper, matrix and scalar bounds for the solution of the Continuous Algebraic Lyapunov Equation (CALE), when the coefficient matrices are the state matrices of real data models. The bounds are illustrated for two different models describing the dynamic behavior of power systems - a two-area power system and an interconnected power system. Some important conclusions referring to the accuracy of the respective estimates are made, as well.

#### Mots clés

- Lyapunov equation
- solution bounds
- power systems

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Bipolar Fuzzy Line Graph of a Bipolar Fuzzy Hypergraph

Pages: 13 - 17

#### Résumé

This paper introduces the concept of a bipolar fuzzy line graph of a bipolar fuzzy hypergraph and some of the properties of the bipolar fuzzy line graph of a bipolar fuzzy hypergraph are also examined

#### Mots clés

- Bipolar fuzzy set
- line graph
- hypergraph
- fuzzy hypergraph

#### Résumé

The paper describes economic agents’ integration in clusters on a predefined technological network. The process is divided and directed by three multi-criteria models. The first one allows selection of economic agents. The second one aims at definition of alternative cluster designs. The third model evaluates the risk of the clusters. The process and models are tested on nineteen economic agents.

#### Mots clés

- Multi-criteria decision
- economic clustering
- small and medium enterprises
- risk evaluation

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Codes Correcting Limited Patterns of Random Errors Using S-K Metric

Pages: 34 - 45

#### Résumé

Coding is essential in all communications and in all multi-operation devices, and errors do occur. For error control, the method in vogue is to use code words with redundant digits. The number of redundant digits is determined based on two things − the number of messages and the kind of errors that need to be controlled. For efficient coding the redundant digits have to be kept to the minimum.

In this paper we introduce the idea of limited error patters while using the code alphabet {0,1, 2,..., 1},mod , q Z = q − q when q > 3. We define limitations of the errors in a position by substitution of the character there by a specified number of other characters, rather than by any other character. This is not possible through Hamming approach, because there a character in an error could be substituted by any other of the q-1 characters. The firm mathematical base is provided by use of a metric from the class of S-K metrics, Hamming metric being one of these.

The paper gives upper bounds on the codeword lengths for various kinds of “random limited error patterns”. Examples and discussion bring out the tremendous improvement and generalization of Rao Hamming bound.

#### Mots clés

- Hamming distance
- S-K metric
- error patterns
- error control in codes
- bounds

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Escape-on-Sight: An Efficient and Scalable Mechanism for Escaping DDoS Attacks in Cloud Computing Environment

Pages: 46 - 60

#### Résumé

Availability is one of the primary security issues in Cloud computing environment. The existing solutions that address the availability related issues can be applied in cloud computing environment, but because of their unique characteristics, such as on-demand self service, rapid elasticity, etc., there is a need to develop a detection mechanism that must satisfy the characteristics and an optimal profit for the Cloud Service Provider (CSP). A solution named Escape-on- Sight (EoS) algorithm is proposed in this paper that helps in detecting the attacker’s characteristics by analyzing traffic conditions stage by stage and protects the Data Center (DC) from malicious traffic. The profit analysis shows that the proposed approach has a reasonable chance of deploying EoS mechanism at DCs that are prone to DDoS attacks.

#### Mots clés

- Availability
- Cloud computing
- datacenter
- DDoS
- EoS
- CSP

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Predicting Student Performance by Using Data Mining Methods for Classification

Pages: 61 - 72

#### Résumé

Data mining methods are often implemented at advanced universities today for analyzing available data and extracting information and knowledge to support decision-making. This paper presents the initial results from a data mining research project implemented at a Bulgarian university, aimed at revealing the high potential of data mining applications for university management.

#### Mots clés

- Educational data mining
- predicting student performance
- data mining classification

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A Method for Extracting Knowledge from Decision Tables in Terms of Functional Dependencies

Pages: 73 - 82

#### Résumé

The problem of extracting knowledge from decision tables in terms of functional dependencies is one of the important problems in knowledge discovery and data mining. Based on some results in relational database, in this paper we propose two algorithms. The first one is to find all reducts of a consistent decision table. The second is to infer functional dependencies from a consistent decision table. The second algorithm is based on the result of the first. We show that the time complexity of the two algorithms proposed is exponential in the number of attributes in the worst case.

#### Mots clés

- Relational database
- functional dependency
- rough set theory
- decision table
- reduct

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Using Decision Trees for Identification of Most Relevant Indicators for Effective ICT Utilization

Pages: 83 - 94

#### Résumé

This paper offers a brief overview of the research of ICT utilization and benefits of its usage. The results of several important studies conducted worldwide are presented. One of them is a study by the World Economic Forum that we use as the basis of our research. This study covers 134 countries, NRI (Network Readiness Index) is used as a parameter to distinguish the readiness of different countries to adopt ICT. NRI consists of 68 indicators that are organized into three groups. Each group describes one of the three main factors crucial for effective utilization of ICT: Environment, Readiness and Usage. The observed countries are divided into four groups (leaders, followers, league III and league IV) and classification by a decision tree is conducted. The decision tree method is applied to each of the three main factors and the results are presented by means of F1 measure.

#### Mots clés

- NRI-Network Readiness Index
- decision trees
- effectiveness of ICT utilization

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Shadow Detection and Removal from a Single Image Using LAB Color Space

Pages: 95 - 103

#### Résumé

A shadow appears on an area when the light from a source cannot reach the area due to obstruction by an object. The shadows are sometimes helpful for providing useful information about objects. However, they cause problems in computer vision applications, such as segmentation, object detection and object counting. Thus shadow detection and removal is a pre-processing task in many computer vision applications. This paper proposes a simple method to detect and remove shadows from a single RGB image. A shadow detection method is selected on the basis of the mean value of RGB image in A and B planes of LAB equivalent of the image. The shadow removal is done by multiplying the shadow region by a constant. Shadow edge correction is done to reduce the errors due to diffusion in the shadow boundary.

#### Mots clés

- Shadow detection
- shadow removal
- LAB colour space
- illumination
- reintegration

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New Reference-Neighbourhood Scalarization Problem for Multiobjective Integer Programming

Pages: 104 - 114

#### Résumé

Scalarization is a frequently used approach for finding efficient solutions that satisfy the preferences of the Decision Maker (DM) in multicriteria optimization. The applicability of a scalarization problem to solve integer multicriteria problems depends on the possibilities it provides for the decrease of the computing complexity in finding optimal solutions of this class of problems. This paper presents a reference-neighbourhood scalarizing problem, possessing properties that make it particularly suitable for solving integer problems. One of the aims set in this development has also been the faster obtaining of desired criteria values, defined by the DM, requiring no additional information by him/her. An illustrative example demonstrates the features of this scalarizing problem.

#### Mots clés

- Multicriteria optimization
- integer programming
- scalarization function