• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.623-628
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• 2000

Video-on-demand system in which users can request any video through the network at any time is made possible by rapid increase in network bandwidth and capacity of the media server. However true video-on-demand system cannot support all requests since bandwidth requirement is still too demanding. Therefore efficient bandwidth reduction algorithm is necessary. both the piggybacking method and the batching method are novel solutions that can provide more logical number of streams than the physical system can support. Of course each of them has its pros and cons. hence piggybacking with batching-by-size can take advantage of both the schemes. Some parameters such as the size of batch and the size of the catch-up window should be adjusted and order to maximize the bandwidth reduction for piggybacking with batching-by-size method. One of the most important parameters is decided optimally in this paper. Simulation shows that the optimized parameter can achieve considerable reductionand consequently remarkable enhancement in performance.

• Journal of the Korean Society for information Management
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• v.21 no.2
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• pp.249-267
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• 2004

Although MARC can define the detail cataloguing data, it has complex structures and frameworks to represent bibliographic information. On account of these idiosyncratic features of MARC, XML DTD or RDF/S that supports simple hierarchy of conceptual vocabularies cannot capture MARC formalism effectively. This study implements bibliographic ontology by means of abstracting conceptual relationships between bibliographic vocabularies of MARC. The bibliographic ontology is formalized with OWL that can represent the logical relations between conceptual elements and specify cardinality and property value restrictions. The bibliographic ontology in this study will provide metadata for cataloguing data and resolve compatibility problems between cataloguing systems. And it can also contribute the development of next generation bibliographic information system using semantic Web services.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.7-12
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• 2005

This paper deals with the fuzzy modeling for the complex and uncertain nonlinear systems, in which conventional and mathematical models may fail to give satisfactory results. Finally, we provide numerical examples to evaluate the feasibility and generality of the proposed method in this paper. The expert system which introduces fuzzy logic in order to process uncertainties is called fuzzy expert system. The fuzzy expert system, however, has a potential problem which may lead to inappropriate results due to the ignorance of some information by applying fuzzy logic in reasoning process in addition to the knowledge acquisition problem. In order to overcome these problems, We construct fuzzy inference network by extending the concept of reasoning network in this paper. In the fuzzy inference network, the propositions which form fuzzy rules are represented by nodes. And these nodes have the truth values representing the belief values of each proposition. The logical operators between propositions of rules are represented by links. And the traditional propagation rule is modified.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.603-610
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• 2001

Industrial processes are normally operated by skilled humans who have the cumulative and logical information about the system. Fuzzy control has been investigated for many application. Intelligent control approaches based on fuzzy logic have a chance to include human thinking. This paper represents modeling approach based upon operators knowledge without mathematical model of the system and optimize the controller. The experimented system is constructed for sending a ball to the goal position using wind of two DC motors in the predefined path. A vision camera to mimic human eyes detects the ball position. The system used in this experiment could be hardly modeled by mathematical methods and ould not be easily controlled by conventional manners. The controller is designed based on the input-output data and experimental knowledge obtained by trials, and optimized under the predefined performance criterion. And this paper shows the data adaptation for changeable operating condition. When the system is driven in the abnormal condition with unconsidered noise, the new optimal operating parameters could be defined by adjusting membership functions. Thus, this technique could be applied in industrial fields.

• The KIPS Transactions:PartB
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• v.10B no.7
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• pp.785-794
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• 2003

Computer simulation of natural phenomena has been inclined to graphic processing for visual reality. This negligence of cosmic causalities in their occurrence and natural laws in their development should lead to limited degree of immersion to the users. We attempt to develop a logical framework for authentic simulation of diverse, unpredictable occurrence and development of natural phenomena (such as solar radiation and wind) based on their associated inherent laws and principles. To this end we structure the relevant objects organized in an ontology and propose a data management method. Then we describe our simulation method for the natural phenomena as delimited in phases and present modeling techniques for qualitative changes of physical objects due to their factors' values beyond normal ranges.

• Wind and Structures
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• v.29 no.6
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• pp.471-488
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• 2019

Wind pressure is a critical argument for the wind-resistant design of structures. The attempt, however, to explore the wind pressure field on buildings still encounters challenges though a large body of researches utilizing wind tunnel tests and wind field simulations were carried out, due to the difficulty in logical treatments on the scale effect and the modeling error. The full-scale measurement has not yet received sufficient attention. By performing a field measurement, the present paper systematically addresses wind pressures on the rectangular attic of a double-tower building. The spatial and temporal correlations among wind speed and wind pressures at measured points are discussed. In order to better understand the wind pressure distribution on the attic facades and its relationship against the approaching flow, a full-scale CFD simulation on the similar rectangular attic is conducted as well. Comparative studies between wind pressure coefficients and those provided in wind-load codes are carried out. It is revealed that in the case of wind attack angle being zero, the wind pressure coefficient of the cross-wind facades exposes remarkable variations along both horizontal and vertical directions; while the wind pressure coefficient of the windward facade remains stable along horizontal direction but exposes remarkable variations along vertical direction. The pattern of wind pressure coefficients, however, is not properly described in the existing wind-load codes.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.582-592
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• 2001

Video indexing plays an important role in the applications such as digital video libraries or web VOD which archive large volume of digital videos. Video indexing is usually based on video segmentation. In this paper, we propose a software tool called V2Web Studio which can generate video clips utilizing shot boundary detection algorithm. With the V2Web Studio, the process of clip generation consists of the following four steps: 1) Automatic detection of shot boundaries by parsing the video, 2) Elimination of errors by manually verifying the results of the detection, 3) Building a modeling structure of logical hierarchy using the verified shots, and 4) Generating multiple video clips corresponding to each logically modeled segment. The aforementioned steps are performed by shot detector, shot verifier, video modeler and clip generator in the V2Web Studio respectively.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.115-121
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• 2012

Existing but largely unused binary star model capabilities are examined. An easily implemented scheme is parameterization of starspot growth and decay that can stimulate work on outer convection zones and their dynamos. Improved precision in spot computation now enhances analysis of very precise data. An existing computational model for blended spectral line profiles is accurate for binary system effects but needs to include damping, thermal Doppler, and other intrinsic broadening effects. Binary star ephemerides had been found exclusively from eclipse timings until recently, but now come also from whole light and radial velocity curves. A logical further development will be to expand these whole curve solutions to include eclipse timings. An attenuation model for circumstellar clouds, with several absorption and scattering mechanisms, has been applied only once, perhaps because the model clouds have fixed locations. However the clouds could be made to move dynamically and be combined into moving streams and disks. An area of potential interest is polarization curve analysis, where incentive for modeling could follow from publication of observed polarization curves. Other recent advances include direct single step solutions for temperatures of both stars of an eclipsing binary and third body kinematics from combined light and velocity curves.

• Korean Journal of Computational Design and Engineering
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• v.18 no.3
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• pp.177-188
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• 2013

The construction industry consists of various and massive architectural information as an architectural process includes a variety of design stages with cooperation of many disciplines. Particularly, architectural information is generated and managed through the life cycle of a building, from conceptual design stage to the construction and maintenance. A Building Information Model (BIM) serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle from inception onward. BIM technology accomplished quantitative development being utilized in various disciplines. However, it is necessary to develop environment and requirement for qualitative improvement of BIM based project. Particularly, requirement is very important for architectural design evaluations. The purpose of this study is to develop and apply of quality control check-list for improving the quality of architectural design in BIM environments. To achieve this purpose, the authors have investigated case study for open BIM data quality control (software, guideline and application case) and classified quality control targets according to physical/logical quality control and data quality. In addition, the authors have defined open BIM based quality control process and developed quality control check-list. Finally, the authors have developed automatic quality check system using requirements for efficient quality control based on open BIM.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.1-10
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• 2014

Cloud computing provides flexible and efficient mass data analysis platform. In this paper, we define a new resource provisioning architecture in the public cloud, named PCIA. In addition, we provide a service model of PCIA and its new naming scheme. Our model selects the proper number of physical or virtual resources based on the requirements of clients. By the analysis of performance variation in the PCIA, we evaluate the relationship between performance variation and resource provisioning, and we present key standards for cloud system constructions, which can be an important resource provisioning criteria for both cloud service providers and clients.