• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1051-1060
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• 2003

The heat and mass transfer on two kinds of tube surfaces (bare stainless steel tube and Teflon coated tube) in steam-air mixture flow are experimentally studied to obtain design data for the heat exchanger of the latent heat recovery from flue gas. In the test section, 3-tubes are horizontally installed, and steam-air mixture is vertically flowed from the top to the bottom. The pitch between tubes is 67mm, the out-diameter of tube is 25.4mm, and the thickness is 1.2mm ; blockage factor (cross sectional tube area over the cross sectional area of the test section) is about 0.38. All of sensors and measurement systems (RTD, pressure sensor, flow-meter, relative humidity sensor, etc.) are calibrated with certificated standard sensors and the uncertainty for the heat transfer measurement is surveyed to have the uncertainty within 7%. As experimental results, overall heat transfer coefficient of the Teflon (FEP) coated tube is degraded about 20% compared to bare stainless tube. The degradation of overall heat transfer coefficient of Teflon coated tube comes from the additional heat transfer resistance due to Teflon coating. Its magnitude of heat transfer resistance is comparable to the in-tube heat transfer resistance. Nusselt and Sherwood numbers on Teflon (FEP) coated surface and bare stainless steel surface are discussed in detail with the contact angles of the condensate.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.908-914
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• 1996

A number of techniques have been studied for handling uncertainty in the development of expert systems. One of techniques adopted in many expert systems is the Dumpster-Shafer Evidence combination scheme. This has been the main focus among others due to is favorable features and computational complexity. In this paper, we develop and algorithm to deal with the exponential complexity inherent in Dempster-Shafer evidence combination. In the evidence combination process, we divide the frame of discernment into two groups, one for those common in both belief functions and the other for the rest. A property is found that in computing new belief function for the latter group, the result of evidence combination show linear change. The irrelevancy factor is derived and used to compute the change. The main idea of the method is to reduce the size of the frame of discernment and thus exponential complexity.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.565-573
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• 2013

Uncertainty in large-scale tourism development is the main reason of the delay on the project. The purpose of this study is to identify the status and effect of this large-scale tourism development project. Huge amount of funds has to be invested prior to the development of this project and with high uncertainty of successful development, the procedure is the most important factor of this project. Therefore, under the basis of these assumptions, we operated a PLS regression analysis to see any factors that has influence during the procedure of the project. The result of the PLS regression analysis resulted that among all of the factors, the participation and role of regional community is the highest priority. In order to lead large-scale tourism development to success is to listen to the ideas of various project-related personnels and form a public - private partnership for evaluation of the project.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.519-527
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• 2014

Adaptive arrays can minimize contributions from interferences incident onto an sensor array while preserving a signal the direction vector of which corresponds to the array steering vector to within a scalar factor. If there exist errors in the steering vector, severe performance degradation can be caused since the desired signal is misunderstood as an interference by the array. This paper presents an adaptive beamforming method which is robust against steering vector errors, exploiting a range of the desired signal direction. In the presented method, an correlation matrix of array response vectors is obtained through integration over the direction range and a minimization problem is formulated using some eigenvectors of the correlation matrix such that a more accurate steering vector than initially given one can be found. The minimization problem is transformed into a relaxed SDP (semidefinite program) problem, which can be effectively solved since it is a sort of convex optimization. Simulation results show that the proposed method outperforms existing ones such as ORM (outside-range-based method) and USM (uncertainty-based method).

• Journal of Korean Biological Nursing Science
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• v.9 no.2
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• pp.135-142
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• 2007

Purpose: This study was conducted to investigate degree of stress level in CCU patients, and to give a baseline data in developing nursing intervention program to reduce the stress. Method: Subjects of this study were the 100 hospitalized patients of C University Hospital in Seoul City from February to December 2003. The collected data was analyzed by using the SAS program: t-test, Scheff$\acute{e}$ test, and ANOVA analysis were employed to find differences in stress level. Result: The highest stress factor was 'Concern', and next were 'Dependency & limitation', 'Uncertainty', 'Treatment procedure', 'Sleep disturbance', 'Environment' in order. The perceived stress level of CCU patients was 1.65 scores; the highest scored item was 'have to void urine and feces on the bed', next were 'have to use the toilet bowel lying on the bed' in order. The stress level according to characteristics of the subjects was significantly different with the marital status, the presence of religion, the hospitalized days, the economic status, and the admission experience. Conclusion: The stress level of patients in the coronary care unit was high in concern of a disease, family and economic state, in limitation and dependency, and in uncertainty about prognosis of a disease. Further researches are necessary to develop and apply the intervention method of reducing stress level of CCU patients. In addition studies on family members of CCU patients are also recommended.

• Composites Research
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• v.26 no.1
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• pp.29-35
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• 2013

Composite sandwich structure can improve the specific bending stiffness significantly and save the weight nearly 30 percent compared with the composite laminates. However, it has more inherent uncertainties of the material property caused by manufacturing process than metals. Therefore, the reliability-based probabilistic design approach is required. In this paper, the PMS(Probabilistic Margin of Safety) is calculated for the simplified fuselage structure made of composite sandwich to provide the probabilistic reasonable evidence that the classical design method based on the safety factor cannot ensure the structural safety. In this phase, the probability density function estimated by CMCS(Crude Monte-Carlo Simulation) is used. Furthermore, the RBDO(Reliability-Based Design Optimization) under the probabilistic constraint are performed, and the RBDO-MPDF(RBDO by Moving Probability Density Function) is proposed for an efficient computation. The examined results in this paper can be helpful for advanced design techniques to ensure the reliability of structures under the uncertainty and computationally inexpensive RBDO methods.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.40
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• pp.3-30
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• 2008

This article attempts to describe and analyze the rules on the buyer's remedies for lack of conformity under PELS. It shows that such remedies under the PELS operate in a two-tier remedial scheme which is alien to both domestic and international legal systems. That is, repair and replacement take the position of primary remedy, whereas termination, price reduction and damages are secondary remedies which are available only where the primary remedies cannot be invoked. Notwithstanding its superiority, the PELS have some drawbacks in several aspects. First, the PELS seems to place its focus on the factor of cost except the other factors, for instance, the significance of the lack of conformity, when one decides whether the first tier remedies cause the seller unreasonable effort or expense. It is argued that the factors can be considered by referring to art. 1:302 PECL. Second, the PELS does not expressively provide any exclusion of the seller's right to choose between repair or replacement on the basis of unreasonable uncertainty in reimbursing the expenses advanced by the buyer. It argues that if there is such uncertainty, it should be regarded as causing the buyer an unreasonable inconvenience under art. 4:204(1). Third, the PELS does not seem to properly reflect the consumer's interests in that most consumers prefer to have the absolute right of termination as against the commercial sellers who have a relatively stronger bargaining position. The reasons for that is that there is a big hurdle, i.e., a hierarchy of remedies, to be overcome by the consumer to battle with the commercial seller, and that unavoidable vagueness in defining a minor lack of conformity has been often used against the consumer, but in favour of the commercial seller with a strong bargaining position.

• Journal of Korean Academy of Nursing
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• v.35 no.5
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• pp.879-887
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• 2005

Purpose: The purpose of this study was to understand depression in women with endometriosis and to identify the factors influencing depression. Method: The instruments used were the Beck Depression Inventory for depression, Lemaire Scale for endometriosis syndrome, Mishel Uncertainty in Illness Scale-Community form (MUIS-C), the Rosenberg Self-esteem Scale, and Quality of Life (Endometriosis Health Profile Questionnaire; EHP-5) by Jones et al. The Subjects of Study were 118 outpatients diagnosed with endometriosis from 7 hospitals in Busan City and Kyungsangnam-do. Data was collected from Aug 1, 2004 to Jan 31, 2005. For statistical analysis of collected data, frequency analysis, analysis of variance, and stepwise multiple regression analysis were used with the SPSS statistical program. Result: The general characteristic showing a statistically significant difference in depression in the women with endometriosis was marital status. The score of the depression showed a significantly positive correlation with the score of endometriosis TSD(r= .464, p= .000), uncertainty(r= .393, p= .000), and quality of life(r= .543, p= .000). Depression showed a significantly negative correlation with the score of self esteem(r= - .557, p= .000). Stepwise multiple regression analysis revealed that the most powerful predictor of depression in the women with endometriosis was self-esteem ($R^2$=0.311). A combination of self esteem, quality of life, and total symptom distress accounted for $50.0\%$ of the variance in depression in women with endometriosis. Conclusion: The influencing factor on depression in women with endometriosis was self- esteem, quality of life, and endometriosis TSD. Further studies need to be done to identify methods of overcoming and the presentation of depression in endometriosis.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.4
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• pp.57-66
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• 2009

수학적 모델은 수량과 수질의 예측을 위해 현장 조사의 대안으로 사용되어지며 이러한 모델의 사용과 실측에 불확실성이 존재하게 된다. 불확실성에 대한 많은 연구들이 진행되어 왔으나 시나리오에 의한 모델링 과정에서 발생하는 불확실성에 대한 연구는 미흡한 실정이다. 본 연구에서는 산림이 농경지와 목초지로의 변화에 따른 시나리오를 설계한 후 시나리오 적용에 따른 SWAT (Soil and Water Assessment Tool) 매개변수의 불확실성을 분석하고자 하였다. 몬테카를로 기법 (Monte Carlo simulation)을 이용하여 각 매개변수별 1,000개의 난수를 발생하였으며 앙상블 유량모의 기법을 이용하여 미국 Alabama주 카하바강 상류 (50,967ha)를 대상으로 각 난수별 100개의 유량을 통해 불확실성을 분석하였다. 분석 결과 산림지역이 농경지와 목초지로 변화 되었을 때 유출량이 증가하는 것으로 분석되었으며, 임야가 목초지 보다 농경지로 변화되었을 때 유출량은 더욱 증가하는 것으로 나타났다. 각 시나리오별 SWAT 매개변수의 불확실성은 AWC (Available water capacity), CN (Curve number), GWREVAP (groundwater re-evaporation coeffeicient), REVAPMN (minimum depth of water in shallow aquifer for re-evaporation to occur)순으로 크게 나타났으며, Ksat (Saturated hydraulic conductivity)와 ESCO(Soil evaporation compensation factor)는 유출량의 변화에 큰 영향을 미치지 못하는 것으로 분석되었다. 토지피복별 산림 면적이 클 경우 불확실성이 크게 나타나 산림이 목초지와 농경지로 변함에 따라 불확실성은 감소하는 것으로 나타났다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.133-140
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• 2008

The design method of the reinforced concrete structures is converting from the current limit state design method to the reliability based design method and active studies have been done in the US, Europe, and Japan etc. Performance based design method is considering lots of uncertainty of current design provision rationally and make sure that structure have a reliable reliability and safety. The main area of these studies is to secure the non-linear analysis technology with high reliability. The data for reinforced concrete columns tested by many researchers are used to verify the applicability of the nonlinear finite element analysis program (RCAHEST, Reinforced Concrete Analysis in Higher Evaluation System Technology). A comparison is made between analysis and test, calculated safety factor based on reliability theories to applies to analysis result.