• Journal of KIISE:Databases
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• v.31 no.2
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• pp.91-98
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• 2004

DHP mining association rules algorithm maintains previously independent direct hash table to reduce the sire of hash tree containing the frequency number of each candidate large itemset. It performs pruning by using the direct hash table when the hash tree is constructed. The mort large the size of direct hash table increases, the higher the effort of pruning becomes. Especially, the effect of pruning in phase 2 which generate 2-large itemsets is so high that it dominates the overall performance of DHP algorithm. So, following the speedy trends of producing VLM(Very Large Memory) systems, extreme increment of direct hash table size is being tried and one of those trials is perfect hash table in phase 2. In case of using perfect hash table in phase 2, we found that some rearrangement of DHP algorithm got about 20% performance improvement compared to simply ｜H$_2$｜ reconfigured DHP algorithm. In this paper, we examine the feasibility of perfect hash table in phase 2 and propose PHP algorithm, a rearranged DHP algorithm, which uses the characteristics of perfect hash table sufficiently, then make an analysis on the results in experimental environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5559-5564
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• 2015

A variety of routing protocols targeted specifically at mobile ad-hoc network environments have been developed. Mobile ad-hoc network is a self-organizing temporary network, operating without the aid of any established wired infrastructure. The proposed protocol supports seamless communication services between the mobile hosts within a mobile ad-hoc network environments. In particular, our protocol makes faster route re-establishment possible by maintaining multiple paths in each mobile host, and also, the protocol provides reliable communication environments. We compare the performance of RWP model with that of LW model. This paper shows delivery ratio with single path and non-disjoint multiple path according to mobility model and node numbers.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.121-129
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• 2009

Today, it is difficult to re-use and share spatial information, because of the explosive growth of heterogeneous information and specific characters of spatial information accumulated by diverse local agency. A spatial analysis of subsurface spatial informa-tion, one of the National Spatial Data Infrastructure, needs related spatial information such as, topographical map, geologic map, underground facility map, etc. However, current methods using standard format or spatial datawarehouse cannot consider a se-mantic hetergenity. In this paper, the layered ontology model which consists of generic concept, measuremnt scale, spatial model, and subsurface spatial information has developed. Also, the current ontology building method pertained to human experts is a expensive and time-consuming process. We have developed the MDA-based metamodel(UML Profile) of ontology that can be a easy under-standing and flexiblity of environment change. The semantic quality of devleoped ontology model has evaluated by reasoning engine, Pellet. We expect to improve a semantic sharing, and strengthen capacities for developing GIS experts system using knowledge representation ability of ontology.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.4
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• pp.232-237
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• 2019

It has recently been combined with advanced technologies such as AR and VR, and its application range is expanding to various forms of smart signage. However, until now, digital signage service that reaches us is installed in many floating populations such as bus stops, elevators, and banks and is used in the form of providing news, weather, and advertisements. In addition, large companies, government offices, and outdoor advertising companies occupy the market. The use of such services in small and medium-sized businesses and small retail stores is costly and expensive to manage. Also, it is difficult to generalize the market because services and solutions are being deployed in the market in the form of top-down. Therefore, in this paper, we proposed a digital signage system for transmitting a remote video advertisement that uses a show window in front of the store as a beam project screen for small retail stores, and can remotely set and manage and update it in OSGi service platform.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.73-84
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• 2005

An increasing in quantity of multimedia data brought a new problem that expected data should be retrieved fast and exactly. The adequate representation is a key element for the efficient retrieval For this reason, the MPEG-7 standard was established for description of multimedia contents in 2001. Recently, the new metadata were developed to represent characteristics of movie information resources by Korea Federation of Film Archives. In this paper. we designed and implemented a movie information retrieval system. This system used XML schema to accept movie information metada. This system offers a keyword retrieval using high-level metadata based on movie information and similarity retrieval using low-level metadata based on MPEG-7. As a result, that ill be Possible more efficient movie information interchange . movie information metadata reuse and fast retrieve.

• Journal of Software Engineering Society
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• v.29 no.2
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• pp.1-6
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• 2020

Software product line development is a development paradigm that efficiently develops a product family by avoiding redundant development based on separation of the common part and the variable part of the product family. In software product line development, the source code that is used to produce a product family is called a product line code base, and when the product line code base is changed and the products of the product family are affected by the change, the activity of testing the affected products is called a product line regression testing. For product line regression testing, instead of conducting regression testing individually on each product of the product family, a more efficient regression testing would be possible if unnecessary testing that are irrelevant to the change can be avoided. This paper introduces SRTS, which is an automated method to efficiently perform software product line regression testing. SRTS divides the product line code base and test cases based on commonality and variability. Then SRTS identifies and selects the test cases affected by the change. Finally, it reduces unnecessary testing by rerunning only the selected test cases.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.53-63
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• 2013

This paper presents an importance sampling(IS) embedded experimental frame(EF) design for efficient Monte Carlo (MC) simulation. To achieve IS principles, the proposed EF contains two embedded sub-models, which are classified into Importance Sampler(IS) and Bias Compensator(BC) models. The IS and BC models stand between the existing system model and EF, which leads to enhancement of model reusability. Furthermore, the proposed EF enables to achieve fast stochastic simulation as compared with the crude MC technique. From the abstract two case studies with the utilization of the proposed EF, we can gain interesting experimental results regarding remarkable enhancement of simulation performance. Finally, we expect that this work will serve various content areas for enhancing simulation performance, and besides, it will be utilized as a tool to understand and analyze social phenomena.

• Journal of KIISE:Databases
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• v.33 no.4
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• pp.409-422
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• 2006

In general, there can be many reusable intermediate results due to the overlapped windows and periodic execution intervals among Multiple Continuous Queries (MCQ) on data streams. In this regard, we propose an efficient greedy algorithm for a global query plan construction, called GAGPC. GAGPC first decides an execution cycle and finds the maximal Set(s) of Related execution Points (SRP). Next, GAGPC constructs a global execution plan to make MCQ share common join-fragments with the highest benefit in each SRP. The algorithm suggests that the best plan of the same continuous queries may be different according to not only the existence of common expressions, but the size of overlapped windows related to them. It also reflects to reuse not only the whole but partial intermediate results unlike previous work. Finally, we show experimental results for the validation of GAGPC.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.336-346
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• 2001

A wireless ad-hoc network is a temporal network formed by a collection of wireless mobile nodes without the aid of any existing network infrastnlcture or centralized administration. Currently, numerous routing protocols have been developed for changing messages between nodes in a wireless ad-hoc network. Applications of wireless ad-hoc network technology are various and proper routing protocol must be used according to application domain or network size. In a wireless ad-hoc network. some hosts want services from fixed networks. For supporting such services, it is necessary to interconnect wireless ad-hoc networks and fixed networks. The DSMIHDynamic Source Multipath Routing) protocol, proposed in this paper, focuses on supporting seamless communication services between the nodes within a wireless ad-hoc network and providing fixed networks to the mobile hosts in wireless an-hoc networks. In DSMR protocol, each node need not broadcast routing messages periodically. and mobile hosts that to send data packets initiate route request and route establishment procedure. By maintaining multiple paths in each node. faster route re-establishment is also possible in our scheme.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.158-168
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• 2016

This article is to review various methods used to investigate internal and marginal adaptation of fixed dental prostheses, and to summarize a merit, worth, and limitation of each method, using some results of previous studies. The methods of measuring internal and marginal gap are divided into two categories in this study; in vivo and in vitro. In vivo methods are clinical evaluations, including exploration, radiography, and impression technique. In vitro methods are laboratory evaluations such as direct view, cross-sectioning, and silicone replica technique using microscope. Measuring by micro computed tomography (CT) or profilometer is also in vitro methods. In recent years, the development of scanning systems is able to analyze 3-dimensional internal and marginal space in detail. As measuring and analyzing technology become more advanced, the ability to thoroughly examine crown adaptation is becoming both simpler and more efficient.