• Title/Summary/Keyword: System Risk Analysis

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Development of the Curriculum for Care Manager of the Elderly (노인 케어매니저 양성을 위한 교육과정(안))

  • Han, Suk-Jung;Yoon, Soon-Ho;Kim, Young-Hye;Kim, Il-Ok;Shin, Sung-Rae;Lee, Kyung-Soon;Oh, Pok-Ja
    • The Journal of Korean Academic Society of Nursing Education
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    • v.11 no.2
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    • pp.240-251
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    • 2005
  • Purpose: The purpose of this study was to develop a curriculum for care manager based on the results of professional workshops and through the analysis of the roles and curriculums of care managers in other countries. Method: The process of this study included a review of literature, getting advice from various experts, a review of the present state of education programs at abroad. Result: This study revealed the basic content of care manager education which includes understanding health care and welfare delivery system. process of care manager, resource management, legal and ethical issues, management of health and a life style of elderly, communication, stress management. The major roles of care manager was revealed as the one who assess the needs of elders, making a care plan, evaluator, supporter, coordinator and a risk manager who coordinates, validates and reassesses various services needed by elderly. Conclusion: These results can be utilized in care manager educational program for raising the quality of care manager and care management services.

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An Estimation of the Amount of Ship's Ballast Water to be Discharged at Korean Major Ports (국내 주요항만에서의 선박평형수 배출량 추정)

  • Choi, Hark-Sun;Kim, Han-Soo;Lee, Seung-Guk
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.4
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    • pp.284-288
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    • 2009
  • The International Convention for the Control and Management of Ships Ballast Water & Sediments was adopted by consensus at a diplomatic conference of IMO at 2004. To prepare the Ballast Water Management Convention, fundamental technologies such as treatment system, type approval, risk assessment and various technical informations for formulation of the regulation for national strategy shall be developed. The information item of voyage and discharge of ship's ballast water are gathered by visiting vessel and agent at port. Using the 97 results by ships type characteristic analysis on the relation between loading/unloading and discharge/uptake of ballast water, the amounts of discharge/uptake of ballast water at each port and all of country in Korea are predicted. Hence, It is apparent that the uptake of ballast water is predicted to about 70 million ton in total of Busan, Incheon, Kwangyang and Ulsan ports at 2006 which is over 3 times than discharges.

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Hydrogen explosion effects at a containment building following a severe accident (중대사고시 수소폭발이 격납건물에 미치는 영향)

  • Ryu, Myeong-Rok;Park, Kweon-Ha
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.3
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    • pp.165-173
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    • 2016
  • On March 11, 2011, a massive earthquake measuring 9.0 on the Richter scale and subsequent 10-.14 m waves struck the Fukushima Daiichi (FD) Nuclear Power Plant. The main and backup electric power was damaged preventing the cooling system from functioning. Fuel rods overheated and led to hydrogen explosions. If heat in the fuel rods is not dissipated, the nuclear fuel coating material (e.g., Zircaloy) reacts with water vapor to generate hydrogen at high temperatures. This hydrogen is released into the containment area. If the released hydrogen burns, the stability of the containment area is significantly impacted. In this study, researchers performed an explosion analysis in a high-risk explosion area, analyzing the hydrogen distribution in a containment building [1] and the effects of a hydrogen explosion on containment safety. Results indicated that a hydrogen explosion was possible throughout the containment building except the middle area. If an explosion occurs at the top of the containment building with more than 40% of the hydrogen collected or in the bottom right or left side of the of containment building, safety of the containment building could be threatened.

Characteristics of First Visit Pediatric Patients with Suicidal Ideation and Behavior: An 8-Year Retrospective Chart Review

  • Song, Jungeun;Kweon, Yong-Sil;Hong, Sung Hee;Kim, Joonbeom;Chun, Ka Hye;Bahn, Geon Ho;Yook, Ki-Hwan;Shin, Dongwon;Hong, Hyun Ju
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.31 no.4
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    • pp.185-192
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    • 2020
  • Objectives: Our study aimed to analyze the demographic and clinical characteristics of children and adolescents during their first visit to psychiatric outpatient departments for the management of suicidal ideation and behavior, and to compare the changes before and in 2012 or later. Methods: This multicenter study was conducted at five university hospitals in a metropolitan area in South Korea. Medical records of patients aged 6-18 years were retrospectively reviewed from January 2009 to December 2016. Patients were analyzed by classifying them into suicidal and non-suicidal groups based on their visit to the hospital for management of suicidal ideation or suicide attempt and other mental problems, respectively. Results: There were differences in the year of visit, diagnosis, education level, and referral sources between patients in the suicidal and non-suicidal groups. Multiple regression analysis was conducted based on the sex, education level, referral by school, and diagnosis of depression in patients in the suicidal group, which revealed significant association. Conclusion: Suicide-related problems were significantly associated with the sex, education level, referral by school, and a diagnosis of depression in the patients. A well-connected referral system would be necessary for professional mental health management of high-risk children and adolescents.

Secure and Fine-grained Electricity Consumption Aggregation Scheme for Smart Grid

  • Shen, Gang;Su, Yixin;Zhang, Danhong;Zhang, Huajun;Xiong, Binyu;Zhang, Mingwu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.4
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    • pp.1553-1571
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    • 2018
  • Currently, many of schemes for smart grid data aggregation are based on a one-level gateway (GW) topology. Since the data aggregation granularity in this topology is too single, the control center (CC) is unable to obtain more fine-grained data aggregation results for better monitoring smart grid. To improve this issue, Shen et al. propose an efficient privacy-preserving cube-data aggregation scheme in which the system model consists of two-level GW. However, a risk exists in their scheme that attacker could forge the signature by using leaked signing keys. In this paper, we propose a secure and fine-grained electricity consumption aggregation scheme for smart grid, which employs the homomorphic encryption to implement privacy-preserving aggregation of users' electricity consumption in the two-level GW smart grid. In our scheme, CC can achieve a flexible electricity regulation by obtaining data aggregation results of various granularities. In addition, our scheme uses the forward-secure signature with backward-secure detection (FSBD) technique to ensure the forward-backward secrecy of the signing keys. Security analysis and experimental results demonstrate that the proposed scheme can achieve forward-backward security of user's electricity consumption signature. Compared with related schemes, our scheme is more secure and efficient.

Optimization Methodology for Sales and Operations Planning by Stochastic Programming under Uncertainty : A Case Study in Service Industry (불확실성하에서의 확률적 기법에 의한 판매 및 실행 계획 최적화 방법론 : 서비스 산업)

  • Hwang, Seon Min;Song, Sang Hwa
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.39 no.4
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    • pp.137-146
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    • 2016
  • In recent years, business environment is faced with multi uncertainty that have not been suffered in the past. As supply chain is getting expanded and longer, the flow of information, material and production is also being complicated. It is well known that development service industry using application software has various uncertainty in random events such as supply and demand fluctuation of developer's capcity, project effective date after winning a contract, manpower cost (or revenue), subcontract cost (or purchase), and overrun due to developer's skill-level. This study intends to social contribution through attempts to optimize enterprise's goal by supply chain management platform to balance demand and supply and stochastic programming which is basically applied in order to solve uncertainty considering economical and operational risk at solution supplier. In Particular, this study emphasizes to determine allocation of internal and external manpower of developers using S&OP (Sales & Operations Planning) as monthly resource input has constraint on resource's capability that shared in industry or task. This study is to verify how Stochastic Programming such as Markowitz's MV (Mean Variance) model or 2-Stage Recourse Model is flexible and efficient than Deterministic Programming in software enterprise field by experiment with process and data from service industry which is manufacturing software and performing projects. In addition, this study is also to analysis how profit and labor input plan according to scope of uncertainty is changed based on Pareto Optimal, then lastly it is to enumerate limitation of the study extracted drawback which can be happened in real business environment and to contribute direction in future research considering another applicable methodology.

Analysis of Microbial Contamination in Poultry Slaughtering Operations for the Application of HACCP (HACCP 적용을 위한 도계처리 공정내 미생물 오염의 분석)

  • 홍종해;권혁무;고주언
    • Journal of Environmental Health Sciences
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    • v.22 no.1
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    • pp.45-50
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    • 1996
  • The application of HACCP system, which was adopted by Codex Alimentarius Committee for the safe meat and poultry production, is one of the urgent task for competing in the world trade markets. But there have been no useful analytical studies to identify the causes of contamination in the poultry meat processing plants in Korea. This study was conducted to investigate the potential hazards during the operations by the microbiological examination for the poultry meat processing plant (20,000 birds capacity a day) located in Kangwon province. In spite of air contamination of work places, it may not directly affect the surface contamination of poultry meats. But the risk of Campylobacter jejuni/coli contamination was high. The number of total count was decreased about ten times, but remarkable changes of microbial contamination could not be recognized in each procedure during the operations. The washing water was already contaminated as much as $10^{3-6}CFU/ml$ in SPC before the operations. It means that to keep water tanks hygienic is a primary step to prevent the occurrences of microbial contamination. The overflow and recirculation of water in scalding, washing, and chilling was aslo an important factor for a hygienic control. Based on this study, the followings could be regarded as an important factors for hygenic control in the poultry slaughtering plants on a small scale. The temperature of water used for scalding should be constantly maintained on a required temperature, and the overflow rate of 1~1.5 liter per bird. The carcass surface and the body cavity should be washed thoroughly and the cross-contamination due to facilities, workers, and tools should be prevented. The chilling water sholud be maintained under 5$\circ$C of temperature with ice and overflow, and residual chlorine level of 50 ppm.

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Data Cleaning and Integration of Multi-year Dietary Survey in the Korea National Health and Nutrition Examination Survey (KNHANES) using Database Normalization Theory (데이터베이스 정규화 이론을 이용한 국민건강영양조사 중 다년도 식이조사 자료 정제 및 통합)

  • Kwon, Namji;Suh, Jihye;Lee, Hunjoo
    • Journal of Environmental Health Sciences
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    • v.43 no.4
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    • pp.298-306
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    • 2017
  • Objectives: Since 1998, the Korea National Health and Nutrition Examination Survey (KNHANES) has been conducted in order to investigate the health and nutritional status of Koreans. The food intake data of individuals in the KNHANES has also been utilized as source dataset for risk assessment of chemicals via food. To improve the reliability of intake estimation and prevent missing data for less-responded foods, the structure of integrated long-standing datasets is significant. However, it is difficult to merge multi-year survey datasets due to ineffective cleaning processes for handling extensive numbers of codes for each food item along with changes in dietary habits over time. Therefore, this study aims at 1) cleaning the process of abnormal data 2) generation of integrated long-standing raw data, and 3) contributing to the production of consistent dietary exposure factors. Methods: Codebooks, the guideline book, and raw intake data from KNHANES V and VI were used for analysis. The violation of the primary key constraint and the $1^{st}-3rd$ normal form in relational database theory were tested for the codebook and the structure of the raw data, respectively. Afterwards, the cleaning process was executed for the raw data by using these integrated codes. Results: Duplication of key records and abnormality in table structures were observed. However, after adjusting according to the suggested method above, the codes were corrected and integrated codes were newly created. Finally, we were able to clean the raw data provided by respondents to the KNHANES survey. Conclusion: The results of this study will contribute to the integration of the multi-year datasets and help improve the data production system by clarifying, testing, and verifying the primary key, integrity of the code, and primitive data structure according to the database normalization theory in the national health data.

Lower Extremity Biomechanics while Walking on a Triangle-Shaped Slope (삼각경사면 보행 시 하지 관절 생체역학적 분석)

  • Hong, Yoon No Gregory;Jeong, Jiyoung;Kim, Pankwon;Shin, Choongsoo S.
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.3
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    • pp.153-160
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    • 2017
  • Gait analysis has been conducted in various environments, but the biomechanics during the transition from uphill walking to downhill walking have not been reported. The purpose of this study is to investigate the knee and ankle joint kinematics and kinetics during walking on a triangle-shaped slope compared with those during level walking. Kinematic and kinetic data of eighteen participants were obtained using a force plate and motion capture system. The greater peak ankle dorsiflexion angle and moment and the peak knee extension moment were observed (p<0.05) during both uphill and downhill walking on the triangle-shaped slope. In summary, uphill walking on a triangle-shaped slope, which showed a peak knee flexion of more than $50^{\circ}$ with greater peak knee extension moment, could increase the risk of patellofemoral pain syndrome. Downhill walking on a triangle-shaped slope, which involved greater ankle dorsiflexion excursion and peak ankle dorsiflexion, could cause gastrocnemius muscle strain and Achilles tendon overuse injury.