• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.258-265
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• 2017

At the early stage of the development of high speed propulsion systems, the designers suffer from the lack of both the quantity and the quality of test data. In that situation, the associated uncertainties could not be modeled as probabilistic distribution since probabilistic modelling requires large amount of data. In this paper, instead, the information provided by experts based on their experience and engineering knowledge was used to model uncertainty using the evidence theory. In designing the DCR(Dual Combustion Ramjet) engine, the combustion efficiencies, not well understood and little data existing, are assumed to have been provided by experts. And the uncertainties are quantified by Evidence theory. The quantified uncertainties are incorporated into the optimization. The design variables, area of inlet and area of combustor exit, have been found while satisfying reliability margins of thrust and thermal choking. The results show a reasonable design of the engine under the uncertain circumstances.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.495-508
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• 2005

Moving objects are spatiotemporal data that change their location or shape continuously over time. Their location coordinates are periodically measured and stored i3l the application systems. The linear function is mainly used to estimate the location information that is not in the system at the query time point. However, a new method is needed to improve uncertainties of the location representation, because the location estimation by linear function induces the estimation error. This paper proposes an application method of the cubic spline interpolation in order to reduce deviation of the location estimation by linear function. First, we define location information of the moving object on the two-dimensional space. Next, we apply the cubic spline interpolation to location estimation of the proposed data model and describe algorithm of the estimation operation. Finally, the precision of this estimation operation model is experimented. The experimentation comes out more accurate results than the method by linear function.

• Journal of Korea Port Economic Association
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• v.32 no.1
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• pp.165-178
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• 2016

Container port nowadays becomes one of the most vital link of the transportation chain, plays an important role in trading with other countries. Therefore, evaluating the operational efficiency of container ports to reflect their status and to reveal their position in this competitive environment is very important for port development. Although there have been lots of methods used to measure efficiency in the past, the DEA (Data Envelopment Analysis) model is still the most commonly applied approach. However, the data used in the model sometimes is complex and uncertain to handle using the basic DEA model. In this paper, we applied an uncertainty theory to create an uncertainty DEA model (UDEA), which can solve the limitation of the traditional one. This study mainly focuses on measuring efficiency of 41 container ports by applying proposed an UDEA model. The results show that among 41 container ports, only six container ports are regarded to have efficient operation through the clustering, meanwhile others have technical and scale inefficiencies. We found out that an UDEA model is better to analysis efficiency than existing DEA model.

• Journal of Korea Trade
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• v.26 no.6
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• pp.41-60
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• 2022

Purpose - The policy implications of free trade agreements have traditionally been a matter of debate among economists. The official signing of the Korea-China Free Trade Agreement provides economists with a quasi-natural experiment to analyze the FTA's policy effects. This article aims to more accurately understand the impact of Korea's FTA accession on the macro economy. Design/methodology - This study adopts the counterfactual method based on panel data to find common factors in the generation process of macro data to fit the counterfactual path, to accurately evaluate the effect of the macro policy. Findings - Our research results show that the signing of the Korea-China FTA has a relatively significant short-term positive effect on Korea's economic growth. On average, Korea's real GDP growth rate has increased by 2.1%. This study finds evidence in support of FTA signing not having a significant impact on Korea's GDP growth in the long run. Additionally, we evaluated the impact of the FTA on Korea's imports and exports and found that it had a significant positive impact in the short term, but the trade effect of the FTA is significantly affected by the external macro-environment. Originality/value - First, this study uses macro panel data at the national level to examine the impact of the Korea-China FTA on Korea, and more accurately describes the policy effect of the FTA. Second, our empirical results show that the Korea-China FTA policy impact is subject to occasional changes in the external environment, such as the geopolitical conflict (crisis) between Korea and China, and the US-China trade war. Finally, the analysis shows that the short-term effect of FTA is significant but the long-term is uncertain, which provides empirical evidence for the debate on whether joining FTA can promote national economic growth.

• Korean System Dynamics Review
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• v.8 no.2
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• pp.115-140
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• 2007

Changes in material use, energy use and emissions profiles of steel industry are the result of complex interrelationships among a multitude of technological and economic drivers. To better understand and guide such changes requires that attention is paid to the time-varying consequences that technology and economic influences have on an industry's choice of inputs and its associated outputs. We briefly review the range of policy issues in our paper and assess the impact that climate-change policies may have on energy use and carbon emissions in Korea steel industry. We then present the models of Korea steel industry's energy and product flow regarding environmental regulations by using system dynamics simulation methodology(SD). Time series data and engineering information are combined to endogenously specify changes in technologies, fuel mix, and production processes within dynamic simulation model. Through a various scenario, ramifications that the convention of climate change would to steel industry is analyzed, and based on the study results, strategies against environment changes is contemplated in various perspectives to contribute to minimize the risks concerning the uncertain future and to be conducive to Korea steel industry's sustainable development.

• The Journal of Korean Medicine
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• v.34 no.1
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• pp.69-79
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• 2013

Objectives: The aim of this survey was to investigate utilization, intended use, problems with and demand for medical devices by surveying members of the traditional Korean medical society. Methods: We distributed questionnaires to 13,957 traditional Korean medical doctors via e-mail, and received replies from 1,225. The questionnaire consisted of 4 multiple-choice questions for survey respondent information, 8 multiple-choice questions about the status of medical devices utilizing, and a short answer question about the demand for medical devices. Results: Use of medical devices in traditional Korean medical clinics is common. Diagnostic medical devices are mainly used to assess the patient's condition and to establish a close rapport with clients. In case of therapeutic medical devices, they are usually used for secondary treatment. Issues with traditional Korean medical devices currently in use were ineligibility for national health insurance, low reliability, uncertain validity, and high price. In development of traditional Korean medical equipment, the need for diagnostic medical devices was greater than for therapeutic, and the need for the recording and analysis of medical image data and visualization of medical information was great. Conclusions: There is growing demand for facilitating the development and commercialization of traditional Korean medical devices. To satisfy this demand, research on evaluation indicators that reflect functional and structural clinical information and how to clinically assess the indicators should proceed.

• Korean journal of applied entomology
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• v.52 no.2
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• pp.85-91
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• 2013

A diverse range of taxonomic confusions are brought forth since past taxonomic information including major errors following its initial provision of some uncertain information has repeatedly been applied to Korean Vespidae in its identification. Thus, this study, which made a final summarization of research on Vespidae, provided the list of Korean Vespidae determined except for Eumeninae, with their distributional data. A total of 30 species (including 3 subspecies) belonging to 5 genera of 2 subfamilies are listed: subfamily Vespinae (3 genera/ 18 species) and subfamily Polistinae (2 genera/ 12 species).

• Journal of The Korea Institute of Healthcare Architecture
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• v.18 no.4
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• pp.67-74
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• 2012

Purpose: Since the establishment of Korea Society for the Study of Hospital Architecture, Korea Institute of Healthcare Architecture have carried out various activities to improve the level of healthcare architecture in Korea. Despite of more diverse activities than the beginning, the history and activities of early days of the Society and Institute could be forgotten and omitted. So this paper aims to describe accurately the process of establishment of Korea Society for the Study of Hospital Architecture and Korea Institute of Healthcare Architecture and the activities of the Society and Institute. Methods: Publications and documents issued by Korea Society for the Study of Hospital Architecture and Korea Institute of Healthcare Architecture have been surveyed. And to identify the unwritten activities, personal memo and interviews were also used. Results: The result of this study can be summarized into two points. The first one is that some of the unwritten and uncertain history and activities of the beginning of the KIHA could be identified. The second one is that not also the activities of Korea Society for the Study of Hospital Architecture and Korea Institute of Healthcare Architecture but the activities prior to the Society for the Study could be described. Implications: This research could be the basic data to arrange the history and activities of KIHA.

• Ocean and Polar Research
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• v.34 no.4
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• pp.403-411
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• 2012

Among others, a question that has long been unanswered is why the seasonal variation of volume transport is larger in the Soya and Korea/Tsushima Straits than in the Tsugaru Strait. An attempt is made to answer this question in terms of the island rule with friction being taken into account. The problem is idealized as a simple model. The model results indicate that volume transport through a channel is determined not only by the circulation created around the adjacent island but also by those created around the neighboring islands farther away. The latter is due to the presence of bottom friction in the channels. The volume transports through the Korea/Tsushima, Tsugaru and Soya Straits estimated from the model using observed wind data show the general pattern of observed seasonality, although they contain large errors associated with the uncertain frictional parameter employed in the model. The model indicates that the observed seasonality arises essentially from the fact that wind stress curl changes its sign, from negative in the summer to positive in winter, following a large fluctuation of zero-stress curl latitude east of Hokkaido.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.352-358
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• 2006

We reconsidered the taxonomy of lizards in Korea on the basis of morphological characters of collected specimens and previously published data. A total of 138 specimens were used in this study, which were collected from April 1996 to October 2005, From the observations, we presented keys to classify Korean lizards. Also, we indicated sampling sites for each species on the Korean map. In addition, we added some remarks on the distribution of Gekko japonicus, the study of genus Scincella and the synonym of genus Takydromus. Especially, it was uncertain whether the southern Korean Peninsula is a natural habitat of Takydromus tachydromoides oldi which will be necessary in further study.