• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9C
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• pp.907-912
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• 2005

An efficient method for calculation of observation probability in CDHMM(Continous Density Hidden Markov Model) is proposed in this paper. the proposed algorithm, called FCOP(Fast Computation of Observation Probability), approximate obsewation probabilities in CDHMM by eliminating insignificant PDFs(Probability Density Functions) and reduces the computational load. When applied to a speech recognition system, the proposed FCOP algorithm can reduce the instruction cycles by $20\%-30\%$ and can also increase the recognition speed about $30\%$ while minimizing the loss in its recognition rate. When implemented on a practical cellular phone, the FCOP algorithm can increase its recognition speed about $30\%$ while suffering $0.2\%$ loss in recognition rate.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.107-113
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• 2018

Maintaining adequate residual chlorine concentration is an important criteria to provide secure drinking water. The chlorine decay can be influenced by unstable flow due to the transient event caused by operation of hydraulic devices in the pipeline system. In order to understand the relationship between the transient event and the chlorine decay, the probability density function based on the water demand curve of a hypothetical water distribution system was used. The irregular transient events and the same number of events with regular interval were assumed and the fate of chlorine decay was compared. The chlorine decay was modeled using a generic chlorine decay model with optimized parameters to minimize the root mean square error between the experimental chlorine concentration and the simulated chlorine concentration using genetic algorithm. As a result, the chlorine decay can be determined through the number of transients regardless of the occurrence intervals.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.171-178
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• 2016

In engineering industry, technical documentation refers to any type of documentation that describes handling, functionality and architecture of a technical product. The intended audiences for product technical documentation is the end user, the administrator, service or maintenance technician. Competition and rapid technological evolutions have created pressure to release new and improved products on an increasingly frequent basis. As the technical capabilities of products advance, the technical documentation for those products is becoming longer and complex. The Darwin Information Typing Architecture (DITA) is and XML-based, end-to-end architecture for authoring, producing, and delivering technical documents. DITA is an OASIS standard that allows documentation groups to single-source document for multiple products and users, to automatically publish that documentation in several media formats including PDF and HTML, and to efficiently maintain and update that documentation. This paper study on the various implementation projects for technical documentation using OASIS DITA standard and examines the potential for using DITA as a solution for reconstructing existing technical documentation. Also We offer an incremental adoption approach to effectively implement DITA standard of technical documentation project for domestic firms, while reducing failures.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.247-251
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• 2010

It is very difficult to understand and estimate the heat transfer and flow characteristics in the combustor, which is one of main components in the Auxiliary Power Unit (APU), because its flow filed has very complex structure. In this paper, specified is characteristics of injection and flow through different air goles in the liner, which consist of large circular holes film cooling holes, and tangential air swirl holes. The durability of the liner depends on whether the surface of the liner is exposed to the hot gas over 1000 $^{\circ}C$ of a temperature or net. It is proved that the locations of hot spots estimated from the calculation using CFD are matched well with that from the test. In this study, CFD simulations were performed to examine the heat transfer and temperature distributions in and about a liner wall with film cooling on the wall. This computational study is based on the ensemble average continuity, compressible Navier-Stokes, energy, and PDF combustion equations closed by the standard $k-{\varepsilon}$ turbulence model with standard wall functions for the gas phase and the Fourier equations for conduction in the solid phase.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.1-15
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• 2017

Installation of sensors networks for continuous in-service monitoring of structures and their efficiency conditions is a current research trend of paramount interest. On-line monitoring systems could be strategically useful for road infrastructures, which are expected to perform efficiently and be self-diagnostic, also in emergency scenarios. This work researches damage detection in composite concrete-steel structures that are typical for highway overpasses and bridges. The techniques herein proposed assume that typical damage in the deck occurs in form of delamination and cracking, and that it affects the peak power spectral density of dynamic curvature. The investigation is performed by combining results of measurements collected by long-gauge fiber optic strain sensors installed on monitored structure and a statistic approach. A finite element model has been also prepared and validated for deepening peculiar aspects of the investigation and the availability of the method. The proposed method for real time applications is able to detect a documented unusual behavior (e.g., damage or deterioration) through long-gauge fiber optic strain sensors measurements and a probabilistic study of the dynamic curvature power spectral density.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.139-142
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• 2003

As composite materials are gaining wide acceptance in aircraft structure, repair of damaged composite is becoming an important issue. The issues in composite repair include high cost, material interchangeability, water ingression, and structural integrity. To address these problems, researchers have studied on the composite repair in various aspects. In this paper, an Internet-based advisory service (called Repair Advisory Service, RAS) for composite repair is proposed to increase efficiency for repair process. In the RAS system the web browser is used as its user interface, which provides easy access to the service. The RAS server provides web-based tools for failure prediction, Structural Repair Manual (SRM), automated prepreg cutting process, material properties, inventory and knowledge base. The computer codes implemented for repair design estimate the tensile failure and shear failure of repaired structures. The prediction of failure is based on the maximum strain criterion for tensile failure while elastic-perfect plastic shear failure model is applied for interfacial failure. The OEM's SRM is provided in the PDF format for viewing and searching by web browsers instead of looking up paper version SRM. The knowledge base in this site offers a room to share and distribute ideas, memos, publications, or suggestions from the repair engineers. The fabrication tool of RAS reads repair geometry from engineers then generates a CNC toolpath to cut prepreg patches. The RAS service is open to public and available at http://nano.gsnu.ac.kr/. Broad feedback from field technicians and engineers is welcome to improve the usefulness of RAS.

• Journal of Korea Water Resources Association
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• v.43 no.8
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• pp.709-720
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• 2010

This paper describes the modeling of climate change impact on drought using a conceptual soil moisture model and presents the results of the modeling approach. The future climate series is obtained by scaling the historical series, informed by CCCma CGCM3-T63 with A2 green house emission scenario, using a daily scaling method that considers changes in the future monthly precipitation and potential evapotranspiration as well as in the daily precipitation distribution. The majority of the modeling results indicate that there will be more frequent drought in Korea in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.473-476
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• 2007

Location determination of mobile user via RSSI approach has received ample attention from researchers lately. However, it remains a challenging issue due to the complexities of RSSI signal propagation characteristics, which are easily exacerbated by the mobility of user. Hence, a segmentation-based linear spline interpolation method is proposed to cater for the dynamic fluctuation pattern of radio signal in complex environment. This optimization algorithm is proposed in addition to the current radiolocation's (CC2431, Chipcon, Norway) algorithm, which runs on IEEE802.15.4 standard. The enhancement algorithm involves four phases. First phase consists of calibration model in which RSSI values at different static locations are collected and processed to obtain the mean and standard deviation value for the predefined distance. RSSI smoothing algorithm is proposed to minimize the dynamic fluctuation of radio signal received from each reference node when the user is moving. Distances are computed using the segmentation formula obtain in the first phase. In situation where RSSI value falls in more than one segment, the ambiguity of distance is solved by probability approach. The distance probability distribution function(pdf) for each distances are computed and distance with the highest pdf at a particular RSSI is the estimated distance. Finally, with the distances obtained from each reference node, an iterative trilateration algorithm is used for position estimation. Experiment results obtained position the proposed algorithm as a viable alternative for location tracking.

• Journal of The Korean Association of Information Education
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• v.16 no.3
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• pp.327-336
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• 2012

The Korea government has recently announced "A Master Plan for Smart Education", including application of digital textbooks and composition of education system using cloud computing. Our education system in future circumstance, over the conventional e-learning methods, needs the smart education solutions which enable students to study and communicate on various types of devices. The ongoing government project related with the digital textbook has been performed as mid- and long-term goals, whereas PDF-based e-textbook project, similar to e-book model and, has been already completed for the short-term goal. For the purpose of improved future smart education circumstance, however, a specific strategy is required in the following areas: flexibility of format conversion and independency of original text sources among the multiple device platforms. Therefore, in this paper, we propose a standardization scheme for e-textbook format based on e-book structure. To do this, we survey trends in e-book technologies, and research on standardization of e-book format for digitalization of textbooks, based on the analysis of existing textbooks. Moreover, we produce an example e-book content using our proposed standard method. As a result, our approach can be applied to the future smart education circumstance, and we may say that it will be efficiently applicable to the long-term digital textbook project.

• Journal of Korean Society of Archives and Records Management
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• v.2 no.1
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• pp.119-131
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• 2002

The study designs and implements a KORMARC/EAD integrated system for the Myongji Digital Library Collections. The purpose of this paper is to design the metadata to Myongji Korean History Collections to provide digital information of high quality to clients, and to develop and implement a model for managing digital library collections. In order to test the model and the quality of the derived metadata, we built a metadata management system, which is connected to the existing KORMARC system. The system consists of two modules- a retrieval and an input module. While in the retrieve mode, one can retrieve KORMARC records of books and archival items, with links to modified EAD files for archival items or to image files for books, in the input mode, one can type two types of data such as a catalog data and an inventory data. Finally, we evaluated the proposed system via mail questionnaires, and propose three suggestions to make this system a much more comprehensive and effective system.