• Title/Summary/Keyword: system uncertainty

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Research on void drift between rod bundle subchannels

  • Shasha Liu;Zaiyong Ma;Bo Pang;Rui Zhang;Luteng Zhang;Quanyao Ren;Liangming Pan
    • Nuclear Engineering and Technology
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    • v.56 no.8
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    • pp.3330-3334
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    • 2024
  • Void drift between subchannels in a rod bundle is a crucial phenomenon affecting the calculation accuracy of thermal-hydraulic parameters in SMRs. It holds significant importance in enhancing the precision of safety analysis for SMRs. Existing research on experiment and model of void drift between rod bundle subchannels is relatively rare, and the accuracy of model calculations requires improvement. In this study, experiments on gas-liquid two-phase non-equilibrium flow were conducted to measure the redistribution of two-phase flow induced by void drift in a 1 × 2 rod bundle. The experiment results indicated that in bubby flow regime with void fraction less than 0.3, the void diffusion coefficient showed little variation with changes in void fraction. However, in slug flow and annular flow regimes with void fraction exceeding 0.3, the void diffusion coefficient significantly increased with an increase in void fraction. Furthermore, a new void drift model was developed and validated based on a subchannel code. The overall predicted uncertainty for the outlet void fraction in the rod bundle benchmark was less than 13%.

Design of High-precision Position Control System for Continuous Manual Exercise Medical Devices (연속수동운동 의료기기의 고정밀 위치제어 시스템 설계)

  • Min Soo Park;Oh Yang;Chang Ho Lee
    • Journal of the Semiconductor & Display Technology
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    • v.23 no.3
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    • pp.46-51
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    • 2024
  • In modern society, the incidence of various joint diseases such as degenerative arthritis is steadily increasing with the increase of the elderly population. For the effective treatment of these diseases, the demand for CPM medical devices that increase the range of motion of the joint is increasing, and if a patient is unable to perform exercise on his or her own, it plays a role in helping joint recovery through repetitive and continuous manual exercise to prevent joint stiffness, promote blood circulation, and improve tissue flexibility to shorten the recovery period after joint surgery to efficiently proceed with the rehabilitation process. Due to the uncertainty of the angle measurement method currently in use, it is difficult to accurately evaluate the patient's exercise amount required to improve the range of motion, which can negatively affect the reliability of CPM medical devices and the patient's willingness to rehabilitate. Therefore, a new technology using encoders and angle sensors is needed to overcome the problems arising from the method measured using only the existing Potentiometer.

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Effects of Exclusive Agency Listing and Real Estate Information Network System on Real Estate Broker' Trust and Customer' Satisfactions (전속중개계약과 부동산거래정보망제도가 중개업자 신뢰성과 고객만족에 미치는 영향 분석)

  • Choi, Bong-hyun;Moon, Young-kee
    • Journal of Distribution Science
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    • v.4 no.2
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    • pp.123-144
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    • 2006
  • For the property right's protection of the nation, the uncertainty's dissolution and the reliability's security of real estate trade are very important. With the life style's change, the market of real estate becomes diversification, and the level of the real estate trade becomes diversification. But compared with this, the trade system of the real estate has not broken away from the mode in the past yet. To cope with it actively, it needs to review the real estate trade form. Especially, it needs to investigate a plan that can advance the Agency Listing method. The Exclusive Agency Listing and the real estate Information Network System have been the usual system in some advanced countries like America, Japan. It is the system that establishes the real estate brokerage's trade order and encourages the execution for the real estate client's property right's protection and benefit offer. In our country, The Exclusive Agency Listing and the real estate Information Network System were created in the revised real estate brokerage law in 12, 1993. But because of varies of questions, it can not be settled down. So this paper will develop the characteristic factors of the Exclusive Agency Listing and the real estate Information Network System revitalization and examine the mutual relation depends on the factors. And these factors were studied through the proved analysis to the effecting made on the Agency function's consideration and real estate broker' trust and customer satisfaction. So depends on these, the existed value now will present the revitalization plan and political implication about the Exclusive Agency Listing and the real estate Information Network System.

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Recommendation and current status in exposure assessment using monitoring data in ship building industry - focused on the similar exposure group(SEG) (조선업의 작업환경측정결과를 이용한 노출평가의 문제점과 해결방향 - 유사노출군을 중심으로 -)

  • Roh, Youngman;Yim, Hyeon Woo;Kim, Suk Il;Park, Hyo Man;Jung, Jae Yeol;Park, Sook Kyung;Kim, Hyun-Wook;Chung, Chee Kyung;Lee, Won Chul;Kim, Jung Man;Kim, Soo Keun;Koh, Sang Baek;Karl, Sieber;Kim, Euna;Choi, Jung Keun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.11 no.2
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    • pp.126-134
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    • 2001
  • Statistical approaches for analysis of data from the limited number of samples in ship building industry(SBI) collected by an industrial hygienist for checking compliance to an occupational standard were considered. Sampling for compliance usually has been guided by judgment selection, rather than true randomness, resulting in the creation of compliance samples which approximate a censored sample from the upper tail of the exposure distribution. Similar exposure groups(SEGs) including welding and painting process were established to assess representative values in each groups after reviewing the whole production line in SBI. For the convenient statistical approaches, the code has assigned to each SEGs. The descriptive statistics and probability plotting were used to yield the representative values in each SEGs. In the first step, SEGs of 558 were established from 5 ship building companies. The 38 SEGs showed the uncertainty are divided into each 5 companies and assessed the representative values again. The 44 SEGs in each companies was not showed the normal and lognormal distribution was analyzed each data. And also, recommendation was suggested to resolve the uncertainty in each groups.

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Factors Affecting Social Interaction Anxiety of Nursing Students (간호대학생의 사회적 상호작용 불안에 영향을 미치는 요인)

  • Kim, Kyoung-Nam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.417-424
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    • 2020
  • There is increasing tension and anxiety about being evaluated by others such as anxiety, which is felt when others' evaluation is expected or actual, and this is called social interaction anxiety. The purpose of this study was to develop a nursing intervention program that can reduce social interaction anxiety among nursing college students by analyzing factors affecting social interaction anxiety in nursing college students. The subjects of this study were four nursing college students in B city and C city. The survey data were analyzed using frequencies, percentages, means, t-test, ANOVA, Pearson correlation coefficient, and stepwise multiple regression with the SPSS WIN 21.0 program. The results of this study show that social interaction anxiety was positively correlated with fear of negative evaluation (r=.67, p<.001), fear of positive evaluation (r=.56, p<.001), and intolerance of uncertainty (r=.44, p<.001). Factors affecting ambivalence over emotional expressiveness in terms of social interaction anxiety was interpersonal relationship (β=.19, p<.001), fear of negative evaluation (β=.43, p<.001), and fear of positive evaluation (β=.34, p<.001). The explanatory power of these variables was 58.1%. Therefore, it is thought that nursing college students need to provide a support system to maintain good interpersonal relationships, to reduce sensitivity to positive and negative evaluation, and to accept and positively evaluate their own ability.

The Hope of the Stroke Patients (뇌졸중환자의 희망)

  • 김이순
    • Journal of Korean Academy of Nursing
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    • v.27 no.1
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    • pp.212-227
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    • 1997
  • Cerebrovascular diseases in Korea is an important health problem since mortality and mobidity have been increased rapidly. It marked the 2nd cause of specific death rates in 1993. The stroke causes physical function disorder due to hemiparalysis and emotional disorder, and stroke patients experience helplessness, powerlessness. sense of alienation and loss of hope. These feelings make the rehabilitation difficult because they lose the will of life. The subjects of the study were seven citizens who live in Pusan, are over 50 years old and belong to low income-level. The data were collected from Jan. to Sep. 1995. The researcher as a caregiver and volunteer made confidence of them and asked for their agreement on the purpose of the study. The subjects expressed their experience as openheartedly as possible. The analysis of the data was made through the phenomenological analytic method suggested by Giorgi, which is as follows ; as an unit of description which include the subject' expressions and the researcher's observation, it is examined the theme that express the hope experience with the subject's language(underlining), and the focal meanings are identified. The focal meaning is the crystalization of the theme, which is written in the language of the researcher. After intergrating the focal meaning and make the situated structural description as the meaning of the hope experience identified on each subject's point. After intergrating the situated structural description and make the general structural description as the meaning of the hope experience identified on total subject's point then the systemizing of the structure of the hope experienced phenomena and the flowing of the conciousness was researched. The conclusions of this study was as follows : The ten sources of hope which the subjects experienced were sorted as under 〈mutual relations to others : spouse, children, relatives, fellow believer. health professioner. associate patient group〉, 〈spiritual dependence〉. 〈recovery of physical function〉. 〈rumination of the past life〉, 〈expectation of the future〉. 〈economic power〉, 〈belief〉, 〈ability〉. 〈spontaneous participation〉 and 〈recovery of roles〉. Their hope was spoken out by the following two kinds of linguistics. First. the hope was expressed in the affirmative expression as follows : 〈 to be dependable〉, 〈to make efforts〉, 〈to keep under control〉, 〈to desire〉, 〈to be pleasant〉, 〈to be peaceful〉, 〈to be grateful〉, 〈to give help〉, 〈self-confidence. Courage〉, 〈to be happy〉, 〈to satisfy oneself〉, 〈to share with others〉, 〈to understand〉 and 〈to be affected, be impressed〉 Second, the hope was expressed in the negative on pression as under : 〈to be distressed〉, 〈to be uneasy〉, 〈to be sorry, be unsatisfied〉 〈despair〉, 〈to abandon〉, 〈to be fearful〉, 〈to suffer〉, 〈to bear a burden〉 〈to be confused〉, 〈to be solitary〉, 〈chest trouble〉, 〈to feel heavy〉 〈grief〉, 〈to be daunted〉, 〈to get angry〉, 〈to be uncomfortable〉, 〈to have something regretable〉 and 〈to feel guilty〉. And their hope was expressed by the following four behavioral expressions : 〈physical sphere〉, 〈psychological sphere〉, 〈social support sphere〉 and 〈spiritual sphere〉. The reaction patterns of their hope experience appeared in the following 4 coping method : 〈conquest type〉, 〈dependence type〉, 〈adaptation type〉 and 〈fate type〉. Finally, in the hope structure the sense of certainty don't always coexict with the sense of uncertainty, When the stroke patients try to search for the best quality of life, the senses of certainty and uncertainty make a continual cyclic system in the hope structure.

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Estimation of Engine Output for Marine Diesel Engines (선박용 디젤엔진의 출력산정에 관한 연구)

  • Jung, Kyun-Sik;Lee, Jin-Uk;Jung, Jin-Ah;Choi, Jae-Sung
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.4
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    • pp.436-442
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    • 2011
  • To obtain the engine output correctly is basically very important factor for estimating a engine performance. But, it has been reported that the IHP measured from electronic indicator such as MIPS(Mean Indication Pressure System) has a deviation compared to mechanical indicator. It was reported by authors that the uncertainty of crank angle for TDC position could be one of the reasons. In this paper, the uncertainty of crank angle for TDC position and its influence to engine output were investigated respectively about M/E and G/E for marine diesel engines. For the purpose, two sampling methods of pressure in cylinder were considered which were 'angle base sampling' and 'time base sampling'. Angle base sampling is real crank angle acquired from angle encoder which is attached to crank shaft and time base sampling is crank angle calculated by detected revolution with Z-pluse of encoder. Time base sampling is same method of MIPS. This paper concluded that time base sampling method is not suitable for obtaining the output of marine diesel engine on board because of instantaneous speed variation and load fluctuation. Also it is verified that the variation of engine speed by load fluctuation should be one of reasons additionally in case of M/E.

Application of Accrual Basis for Calculation of Prolongation Cost in Construction Projects (공기연장 추가간접비 산정기준의 발생주의방식 적용 연구)

  • Jeong, Kichang;Lee, Jaeseob
    • Korean Journal of Construction Engineering and Management
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    • v.19 no.5
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    • pp.111-120
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    • 2018
  • Recently, Domestic public construction projects are experiencing a great deal of disputes because of the growing uncertainty about the criteria for calculating the prolongation cost. In addition, researchers have been studying various systems and proper cost estimates in an effort to reduce the uncertainty of these systems and the occurrence of disputes. However, there is no standard yet for social consensus. Meanwhile, The study on the classification system according to the recognition standard of accounting has been systematically studied. As a result, the concepts of accrual and cash basis are defined separately. The purpose of this study is to verify the possibility of applying the concept of 'accrual basis' to the Standard for calculation of prolongation cost. Therefore, As a result of analyzing the occurrence pattern of Job-site overhead cost, it is confirmed that actual costs can not be calculated by the cash-basis method. In particular, the implications of the necessity of the accrual-basis method should be more strictly indicated in the case of items such as indirect labor costs and welfare benefits. In addition, the contractor 's claim report and the appraisal report were examined. As a result, it was confirmed that the calculation situations of prolongation costs are biased to the cash-basis method. In this way, it is suggested that necessary to supplement the calculation standard of the actual costs from the point of view of accrual basis.

Development of Computer Code for Simulation of Multicomponent Aerosol Dynamics -Uncertainty and Sensitivity Analysis- (다성분 에어로졸계의 동특성 묘사를 위한 전산 코드의 개발 -불확실성 및 민감도 해석-)

  • Na, Jang-Hwan;Lee, Byong-Whi
    • Nuclear Engineering and Technology
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    • v.19 no.2
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    • pp.85-98
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    • 1987
  • To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

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Estimation of reflectivity-rainfall relationship parameters and uncertainty assessment for high resolution rainfall information (고해상도 강수정보 생산을 위한 레이더 반사도-강수량 관계식 매개변수 보정 및 불확실성 평가)

  • Kim, Tae-Jeong;Kim, Jang-Gyeong;Kim, Jin-Guk;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.54 no.5
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    • pp.321-334
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    • 2021
  • A fixed reflectivity-rainfall relationship approach, such as the Marshall-Palmer relationship, for an entire year and different seasons, can be problematic in cases where the relationship varies spatially and temporally throughout a region. From this perspective, this study explores the use of long-term radar reflectivity for South Korea to obtain a nationwide calibrated Z-R relationship and the associated uncertainties within a Bayesian inference framework. A calibrated spatially structured pattern in the parameters exists, particularly for the wet season and parameter for the dry season. A pronounced region of high values during the wet and dry seasons may be partially associated with storm movements in that season. Overall, the radar rainfall fields based on the proposed modeling procedure are similar to the observed rainfall fields. In contrast, the radar rainfall fields obtained from the existing Marshall-Palmer relationship show a systematic underestimation. In the event of high impact weather, it is expected that the value of national radar resources can be improved by establishing an active watershed-level hydrological analysis system.