• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.3
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• pp.321-331
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• 2008

A model has been constructed in this study for the investigation of physical characteristics of the Gyeonggi Bay and Han River estuary. MIKE 21 HD (HyDrodynamics) has been used for the uncertainty analysis of the tide of the Gyeonngi Bay and Han River estuary. A total of 15 model experiments have been performed for the hydrodynamic parts and the analysis of results have been made in terms of RMSD (Root-mean square deviation) which has been frequently employed in the suitability analysis of hydrological data since the introduction by NERC(1975), U.K. A smaller value of RMSD indicates the more suitability of a parameter to the model. Analysis of the hydrodynamic results has shown that RMSD of the mean tidal range has the largest value of 0.1148 at Yeomha channel while has the smallest value of 0.0400 at Yeonphyong-do, indicating that the uncertainty in the mean tidal range on near-shore side is larger than that of offshore side. Experiment with reduced water depth by 10% has produced a most significant increase in RMSD. It is therefore implied that the model response changes more sensitively to water depth rather than grid sizes, open boundary forcing and river discharge.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1281-1291
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• 2015

Compared to the past, people can control end devices via open channel. Although this open channel provides convenience to users, it frequently turns into a security hole. In this paper, we propose a new human-centered security risk analysis method that puts weight on the relationship between end devices. The measure derives from the concept of entropy rate, which is known as the uncertainty per a node in a network. As there are some limitations to use entropy rate as a measure in comparing different size of networks, we divide the entropy rate of a network by the maximum entropy rate of the network. Also, we show how to avoid the violation of irreducible, which is a precondition of the entropy rate of a random walk on a graph.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.61-67
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• 2017

Suspended sediment transport plays principal roles in morphological process of natural coastals. It is needed to understand the reason why interaction characteristics of solitary wave and suspended sediment. The present study shows that suspended sediment pickup derived on solitary wave celerity. The 2D prismatic open channel length is 12 m, width is 0.8 m, height is 0.75 m and slope is 1/6. Generation of solitary wave is used by rapidly opening the sluice gate. Bottom surface sediments are laid movable slope section by 0.03 m thickness and experimental sediments are used anathracite and jumoonjin sand. Techniques of suspended sediment pickup rate are designed equipment ASC(Absorptive Suspended sediment Collector). It could directly absorb 5 points suspended sediment by channel water depth. Solitary wave celerity is measued by ADV(Acoustic Doppler Velocimeter). Mounted two video cameras(Model No. : Sony, HDR-XR550) are used to image processing of suspended sediment concentration and turbidity. Suspended sediment pikcup rate(Einstein, 1950) is analyzed to nondimensionalization based on solitary wave celerity. The suspended sediment pickup rate is suggested that more effective plunging breaking type than spilling. The results indicates fundamental suspended sediment transport mechanism between solitary wave celerity and suspended sediment pickup based on laboratory experiments. Finally, the present study suggests that suspended sediment pickup rate by solitary wave is used only characteristics of sediment and solitary wave celerity.

• Journal of Sensor Science and Technology
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• v.7 no.6
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• pp.401-408
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• 1998

A dual-channel automatic ac-dc voltage transfer error measurement system in which the output voltages of two thermal voltage converters which are ac voltage standard are directly measured at the same time to reduce the output voltage drift is described. Forward-reverse measurement method by using a two-channel scanner is used to cancel the offset voltage of the voltmeters. The agreements of the 4-V TVC comparison results between other national standards institute and Korea Research Institute of Standards and Science were less than about ${\pm}2\;ppm$ in the frequency range of $40\;Hz{\sim}100\;kHz$, and were less than about ${\pm}4\;ppm$ at $200\;kHz{\sim}1\;MHz$. Measurement uncertainty is reduced significantly from ${\pm}4\;ppm$ of manual system to ${\pm}3\;ppm$ of new system(up to 100 kHz) typically and great increase in comparison efficiency has been achieved by this system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.464-486
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• 2008

Purpose. Electronic intermediaries (e-intermediaries) are gaining significance in international marketing with the rapid development of e-commerce. The goal of this study is to explain empirically what leads to a higher use of this relatively new exportation alternative. Relying on a resource-based view as our research foundation, we focus on information technology (IT) and non-IT factors as possible determinants. Further, this study brings arguments offered by transaction cost theorists to explain the other non-IT determinants. Methodology/Approach. Data are collected from small and medium-sized enterprises (SMEs) in the electronic industry in Korea and the U.S to ensure generalizability. Ordinary least square (OLS) regression is utilized to analyze the data. Findings. This study raises new issues regarding a relatively new type of exporting channel, e-intermediary. Exporting is regarded as the most appropriate strategy for SMEs in international commerce. A number of SMEs stay away from exporting due to limited resources or lack of knowledge regarding foreign markets. The findings in this study should help SMEs use e-intermediaries more widely by developing appropriate IT-related resources (IT-related human and relationship assets) and dealing with non-IT factors (international competence, environmental uncertainty, and duration of relationship) effectively. Originality/Value/Contribution. This study illustrates the significant role of e-intermediaries, which may help SMEs to penetrate the global market effectively. Finding relevant sources in the global e-marketplace is a challenge for non-experienced users like SMEs. This study proposes e-intermediaries as an effective alternative for them. Another contribution of this study is to show how the use of indirect exporting channels, e-intermediaries, decrease costs in exporting transactions. This study suggests an e-intermediary as a hybrid exporting channel to balance risk and profit.

• Journal of the Korean Society of Costume
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• v.34
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• pp.135-150
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• 1997

The purpose of this study was to inves-tigate the economic performance of the textile industry for the Korean traditional clothes. The content of this paper had two pars; The first part was for the macroeconomic aspects such as location production employments and the produc-tion facilities of the textile industries. The second part was for the microeconomic aspects such as business type branding method fabric type R&D efforts sourc-ing and the distributional channel The major results were as follows: 1.) Most textile firms for the korean traditional clothes were located in Gongju for man-made fibers and in Jinju for silk fabrics. 2) The size of the textile industry in terms of the number of business produc-tion amount the number of employee de-creased during 1994 and 1995 due to the decreasing demand. 3) Over the half of the textile firms produced raw fabric products while only 20% of them were involved in additional dyeing and /or printing finish which re-sulted in low value added production 4) The R&D effort of the textile indus-try for the Korean traditional clothes was very low due to the market uncertainty lack of technological knowledge and most of all small size of the firms 5) Most raw materials for the textile in -dustry were imported with high(25%) tariff rates resulting in price increase and thus low competitiveness in the market. 6) The textile producers sole about the 70% of their products to the wholesalers while selling the rest to the retailers di-rectly. This showed the dual structure of the distribution channel in the textile products. These results suggested some implica-tions for the firms the policy makers and the researchers. The firms should develop new and improved products to increase and create consumer demand by intensive R&D efforts. The government policy ma-kers should give financial supports the firms with R&D investment and legal help such as lowing tariff rate for the raw ma-terials. The researchers from the academy could help the textile industry with the advanced technological knowledge and up-date information for the consumer fashion demand.

• Nuclear Engineering and Technology
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• v.43 no.3
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• pp.301-308
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• 2011

The diametral creep of pressure tubes (PTs) in CANDU (CANada Deuterium Uranium) reactors is one of the principal aging mechanisms governing the heat transfer and hydraulic degradation of the heat transport system (HTS). PT diametral creep leads to diametral expansion, which affects the thermal hydraulic characteristics of the coolant channels and the critical heat flux (CHF). The CHF is a major parameter determining the critical channel power (CCP), which is used in the trip setpoint calculations of regional overpower protection (ROP) systems. Therefore, it is essential to predict PT diametral creep in CANDU reactors. PT diametral creep is caused mainly by fast neutron irradiation, temperature and applied stress. The objective of this study was to develop a bundle position-wise linear model (BPLM) to predict PT diametral creep employing previously measured PT diameters and HTS operating conditions. The linear model was optimized using a genetic algorithm and was devised based on a bundle position because it is expected that each bundle position in a PT channel has inherent characteristics. The proposed BPLM for predicting PT diametral creep was confirmed using the operating data of the Wolsung nuclear power plant in Korea. The linear model was able to predict PT diametral creep accurately.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.28.4-29
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• 2009

The 'Amon-Ra' instrument of the proposed 'EARTHSHINE' satellite is a dual (i.e. imaging and energy) channel instrument for monitoring the total solar irradiance (TSI) and the Earth's irradiance at around the L1 halo orbit. Earlier studies for this instrument include, but not limited to, design and construction of breadboard Amon-Ra imaging channel, stray light suppression and system performance computation using Integrated Ray Tracing (IRT) technique. The Amon-Ra instrument is required to produce 0.3% in uncertainty for both Sunlight and Earthlight measurement. In this study, we report accurate estimation of the output electric signal derived from the orbital variation of radiant exitance from the Sun and the Earth arriving at the aperture and detector plane of the Amon-Ra. For this, orbital irradiance are computed analytically first and then confirmed by simulation using Integrated Ray Tracing (IRT) model. Specially, the results show the arriving power at the bolometer detector surface is $1.24{\mu}W$ for the Sunlight and $1.28{\mu}W$ for the Earthlight, producing the output signal pulses of 34.31 mV and 35.47 mV respectively. These results demonstrate successfully that the arriving radiative power is well within the bolometer detector dynamic range and, therefore, the proposed detector can be used for the in-orbit measurement sequence. We discuss the computational details and implications as well as the simulation results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.85-95
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• 2015

Recent years, nationwide projects for ecological restoration are implemented with emerging issues on the stream ecosystem. In order to enhance effectiveness of the ecosystem restoration and reduce negative impact, the appraisal of effectiveness through the follow-up monitoring and the adaptive management process are executed in consecutive phase. In this study, planning phase, monitoring and adaptive management in Hakui stream which is part of An Yang stream restoration project is introduced as representative ongoing case of effective adaptive management. The aim of this study is to verify the adaptive management process and suggest direction of effective restoration. Restoration project of Hakui stream resulted in increasing number and diversity of species (vegetation, fish, bird, invertbrates, amphibian and reptilia) according to monitoring from 2004 to 2013, and enhancing natural river landscape by evaluation of river naturalness among 2001(before restoration), 2007 (after), 2015 (recent). However, excessive vegetation expansion or sediment deposition on channel over time caused unexpected results such as terrestrialization or degradation of habitats. Adaptive management action such as removing disturbance species (Humulus japonicus)(2007), coppicing willow (2007), release of march snail (2007), creation of wetland (2014) were implemented based on monitoring results. And then appraisal of management action was discussed.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.250-257
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• 2006

Foodservice industry and distribution business could make mutual prpgress when they join forces in responding to environmental uncertainty in an efficient manner. The purpose of this study was to examine the relational characteristics of domestic food service businesses and distribution firms in conjunction with the distribution channels and ensuing conflicts between them, to present possible alternatives on and how they should communicate with each other to achieve a satisfactory result. The relational characteristics and ensuing conflicts of food service businesses and distribution firms appeared to be significantly characterized by incongruities of target, role and perception. The types of relational characteristics that were triggered by the disagreement of roles and perception combined to decrease the intensity of the relational commitment. A satisfactory transactional relationship served to ease their conflicts caused by perceptual disagreement, and the soos of conflicts that were rooted in the discord of roles and of perception that increased the degree of relational commitment. As for relational performance, relational commitment, satisfaction with distribution channel and satisfaction with suppliers allowed them to maintain their relationship on a long-term basis.