• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.997-1005
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• 2010

Recently, there has been a growing interest in the use of WLAN technology due to its easy deployment, flexibility and so on. Examples of WLAN applications range from standard internet services such as Web access to real-time services with strict latency/throughput requirements such as multimedia video and voice over IP on wireless network environments. Fair and efficient distribution of the traffic loads among APs(Access Points) has become an important issue for improved utilization of WLAN. This paper focuses on an AP selection scheme for achieving better load balance, and hence increasing network resource utilization for each user on wireless network environments. This scheme makes use of active scan patterns and the network delay as main parameters of load measurement and AP selection. This scheme attempts to estimate the AP traffic loads by observing the up/down delay and utilize the results to maximize the link resource efficiency through load balancing. We compared the proposed scheme with the original SNR(Signal to Noise Ratio)-based scheme using the NS-2(Network Simulation.2). We found that the proposed scheme improves the throughput by 12.5% and lower the network up/down link delay by 36.84% and 60.42%, respectively. All in all, the new scheme can significantly increase overall network throughput and reduce up/down delay while providing excellent quality for voice and video services.

• Journal of KIISE:Software and Applications
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• v.34 no.7
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• pp.655-666
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• 2007

Reasoners using typical Tableaux algorithm such as RacerPro, Pellet have a problem in Tableaux algorithm large ABox reasoning. Researches to solve these Problems are dealt with Instance Store of University of Manchester which uses Tableaux algorithm based reasoner and DBMS and KAON2 of University of Karlsruhe using Disjunctive Datalog approach. An evaluation experiment for present reasoners is the experiment of TBox reasoning in most of Tableaux algorithm based one. The most of benchmarking tests in reasoning systems haven't done with ABox reasoning based Tableaux Algorithm but done with TBox reasoning based Tableaux Algorithm. Especially, rarely reported benchmarking tests in reasoners have been issued nowadays. Therefore, this thesis evaluates systems with theory of each reasoners for large ABox reasoning that becomes issues recently with typical reasoners. The large AoBx reasoning engine will be analyzed using Instance Store and KAON2 of Manchester University for large ABox processing. At the analysing method, LUBM(Lehigh University BenchMark), benchmarking test method, and it's test system will be introduced. In conclusion, I recommend appropriate reasoner in various environment with experiment result and characteristic of algorithm used for each reasoner.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6303-6309
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• 2014

In this thesis, PBL was applied to the subject for improving students' many skills that modern industrial society demands. Our engineering school developed PBL problems for PBL use, applied the problems to classes and confirmed the effectiveness of PBL. The study subjects were 63 freshman students in H University who took the 'Introduce of computer engineering'. We applied 5 PBL problems for 15 weeks. They wrote and submitted a reflective journal when they finished the every given PBL activity. In addition, they completed a class evaluation form after the activity of 5th PBL Problem ended. The study showed that the students experienced the effectiveness of PBL, such as the comprehension of the studied contents, the comprehension of the cooperative learning, authentic experience, creative problem-solving skills, presentation skills, communication ability, self-directed study ability and confidence. Some difficulties in gathering together and spending much time were also encountered. The students realized that the PBL learning activities were important methods because the students could develop into future intelligent engineers that modern industrial society demands through PBL learning activities. The main goal of an engineering school is to produce specialists with creative problem solving ability so that the effects of this study are quite promising for our engineering school.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.42-52
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• 2002

Information extraction(IE) is a process of recognizing and fetching particular information fragments from a document. In previous work, most IE systems generate the extraction rules called the wrappers manually, and although this manual wrapper generation may achieve more correct extraction, it reveals some problems in flexibility, extensibility, and efficiency. Some other researches that employ automatic ways of generating wrappers are also experiencing difficulties in acquiring and representing useful domain knowledge and in coping with the structural heterogeneity among different information sources, and as a result, the real-world information sources with complex document structures could not be correctly analyzed. In order to resolve these problems, this paper presents an agent-based information extraction system named XTROS that exploits the domain knowledge to learn from documents in a semi-structured information source. This system generates a wrapper for each information source automatically and performs information extraction and information integration by applying this wrapper to the corresponding source. In XTROS, both the domain knowledge and the wrapper are represented as XML-type documents. The wrapper generation algorithm first recognizes the meaning of each logical line of a sample document by using the domain knowledge, and then finds the most frequent pattern from the sequence of semantic representations of the logical lines. Eventually, the location and the structure of this pattern represented by an XML document becomes the wrapper. By testing XTROS on several real-estate information sites, we claim that it creates the correct wrappers for most Web sources and consequently facilitates effective information extraction and integration for heterogeneous and complex information sources.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.501-510
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• 2006

Software streaming allows the execution of stream-enabled software on desktop or portable computing devices like PC, PDA, laptop, cellular phone, etc., even while the transmission/streaming from the server may still be in progress. In this paper, we present an efficient streaming system called Software On-Demand(SOD) streaming system to transmit stream-enabled applications in addition to automatic installation of program registry, environment variables, configuration files, and related components. In particular, we design and implement a SOD system in Linux to provide the user with the instant look-and-click software execution environment such that software download and installation are internally proceeded in a completely user-transparent way. Therefore, the SOD system relieves the user from the tricky, failure-prone installation business. In addition, the software developer now obtains a new, powerful means to advertise and propagate their software products since the user can use software packages via user-friendly UI window or web browser by look-and-click interactive operation. In the paper, we also make a couple of SOD streaming experiments using a spectrum of popular softwares. Based on the analysis of the experiment results, we also propose two performance improvement schemes.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.425-438
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• 1999

In recent days network computing technologies have bee developed rapidly and the extended use of Internet applications for enterprises such as internet/extarnet in and between enterprises has been increased enormously. Therefore the business in the future will be executed by virtual enterprise. Virtual enterprises which is based on information sharing between enterprises are composed of work processes related to information exchange between virtual enterprises, the team members who are representatives of the organizations that are participated in the actual business of virtual enterprises, and members who are representatives of the organizations that are participated in the actual business of virtual enterprises, and environment that are provided by supporting CALS(continuous Acquisition and Life cycle Support or commerce At light Speed). Supporting system of IDE(Integrated Data Environment)for CALS implementation that is provided as an environment of virtual enterprises has to ensure the autonomies of local data and to provide the accessibility of heterogeneous database of enterprises on network transparently for giving user a single global view of data. This paper introduce the design and implementation of the database broker system that can be accessed data transparently by the suers of participated enterprises in the integrated data environment supporting virtual enterprises. The system uses java/CORBA technology in Web environment and Object Query language (OQL) to process the queries of relational database system, object-oriented database system, and file information.

• The Journal of Engineering Research
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• v.5 no.1
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• pp.17-35
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• 2004

Svg(Scalable Vector Graphics) is xml graphic standard recommended by E3C as a language based on xml to express two-dimension graphic. Svg can accommodate all Xml's patency and advantage of interoperability, and can used as various web applications being combined with other xml language. In addition, Svg can be applied to the fields of electronic commerce, geographical information, computer education and advertisement because it can produce high quality of dynamic from real-time data. SVG's application can be enhanced by linking with database. In this paper, we discuss how Svg can be utilized in theater reservation system, not just explaining svg's meaning or ability. Svg added graphic advantage in addition to xml's advantage. This means that svg retains not only graphic element but also xml's softness. It becomes easier to designate seats and add them. Current reservation system provided in general only information on time and price for a ticket, but the system using SVG in this paper provides additional information on position, price, cancellation and purchase availability of seat.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.390-395
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• 2004

The iSTMS is a web-based integrated information system supporting Pre-Service and In-Service Inspection(PSI/ISI) processes for the nuclear power plants of KHNP(Korea Hydro & Nuclear Power Co. Ltd.). The system provides a full spectrum coverage of the inspection processes from the planning stage to the final report of examination in accordance with applicable codes, standards, and regulatory requirements. The major functions of the system includes the inspection planning, examination, reporting, project control and status reporting, resource management as well as objects search and navigation. The system also provides two dimensional or three dimensional visualization interface to identify the location and geometry of components and weld areas subject to examination in collaboration with database applications. The iSIMS is implemented with commercial software packages such as database management system, 2-D and 3-D visualization tool, etc., which provide open, updated and verified foundations. This paper describes the key functions and the technologies for the implementation of the iSIMS.

• Journal of KIISE:Software and Applications
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• v.30 no.11
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• pp.1025-1036
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• 2003

In industry, it is a current trend that systems are developed by using Enterprise JavaBeans(EJB) technology for reducing the cost and the time. Thus, the architecture of EJB is getting more essential to enhance reusability, extensibility and portability of system. However little has been studied in the realm of the practical software architectures for EJB. The architecture has just bean studied in abstract level, but not in concrete level providing the method to substantiate it using the practical J2EE techniques. Just using the EJB technology doesn't guarantee the reusability of the artifacts because EJB specification provides the characteristics and architecture for only fine grained components as session and entity bean. In this paper, we propose the enterprise software architecture for the systems based on EJB and the concrete techniques for implementing that. Also, design patterns of modeling efficient enterprise architecture are represented. By analyzing both the strengths and the weaknesses of suggested design patterns, EJB design patterns which are suitable for each layer of enterprise architecture will be identified. Through the component which design patterns are applied, the architecture can support the optimized relationship between the components. Five techniques for designing components from fine grained to coarse grained based on EJB technology, and architecture design techniques including transaction and assembling techniques are proposed.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.18-30
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• 2009

Recently, although the requirement of quality of VOD content has been transferred upto the class of HD, conventional management systems characterized by OS dependency are truly limited in quality of video image, stability, and compatibility of network environments. In addition most of the content management systems realize very limited capabilities for the real affairs of content management and distribution services in such an OS dependent environment. In this paper, we propose a new scheme of HD-Class VOD Content Management System to solve these problems. We design and implement the proposed system based on open sources by using H.264 video compression method. The proposed system offers high quality content management method based on opened systems and independent on-line distribution method so that it can be realized as an integrated management scheme for VOD contents. Moreover, our system solves the problems of occasional cutting-down video, small screen, and poor image quality that exist in the conventional wmv-type CMS. According to the result of performance evaluation, our system maintains sufficient performance and tolerence for the case of large scale HD content operations or fabrications. We expect that the proposed integrated DB scheme will especially be effective when the content management applications are changed from Internet Web environments to mobile terminal environments.