• Title/Summary/Keyword: reliability of distribution system

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Uncertainty-based Decision on Mitigation of Nitrous Oxide Emissions in Upland Soil (불확도 기반 밭토양 아산화질소 배출 저감 여부 판정)

  • Ju, Okjung;Kang, Namgoo;Lim, Gapjune
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.21 no.4
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    • pp.307-316
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    • 2019
  • In the agricultural sector, greenhouse gas emissions vary depending on the interaction of all ecosystem changes such as soil environment, weather environment, crop growth, and anthropogenic farming activities. Agricultural sector greenhouse gas emissions resulting from many of these interactions are highly variable. Uncertainty-based evaluation that defines the interval with confidence level of greenhouse gas emission and absorption is necessary to take account of the variance characteristics of individual emissions, but research on uncertainty evaluation method is insufficient. This study aims to decide on the effect of reducing N2O emissions from upland soils using an uncertainty-based approach. An uncertainty-based approach confirmed whether there was a difference between confidence intervals in the 5 different fertilizer treatment groups to reduce greenhouse gas emissions. Unlike the statistically significant test with three repetition averages, the uncertainty-based approach method estimated in this study is able to estimate the confidence interval considering the distribution characteristics of the emissions, such as the dispersion characteristics of individual emissions. Therefore, it is considered that the reliability of emissions can be improved by statistically testing the variance characteristics of emissions such as the uncertainty-based approach. It is hoped that the direction of the uncertainty-based approach for the effect of reducing greenhouse gas emissions in agriculture will be helpful in the future development of agricultural greenhouse gas emission reduction technology, adaptation to climate change, and further development of sustainable eco-social system.

Evaluation of Harmless Crack Size of SCM822H Steel by Double Shot Peening (이중 쇼트 피닝에 의한 SCM822H 강의 무해화 균열 크기 평가)

  • Jin-Woo Choi;Seo-Hyun Yun;Yung-Kug Kwon;Gum-Hwa Lee;Ki-Woo, Nam
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.6_2
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    • pp.1011-1017
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    • 2023
  • In this study, the harmless crack size (ahml) by double shot peening (DSP) using shot balls with different diameters was evaluated on carburized, quenched-tempered SCM822H steel. The minimum crack size (aNDI) detectable by non-destructive inspection was also evaluated. The relationship between the crack size (a25,50) that reduces the fatigue limit by 25% and 50% and ahml was evaluated. The residual stress of DSP was greater in SP(0.6+0.08) than SP(0.8+0.08) and appeared deeper in the depth direction. In addition, the hardness below the surface appeared larger. The fatigue limit of DSP increased 2.07 times and 1.95 times compared to non-SP. All ahml of the DSP specimen was determined at the depth (a). The compressive residual stress distribution affects ahml, and the ahml of SP(0.6+0.08), which has a large compressive residual stress and a high fatigue limit, appeared large. ahml of SP(0.6+0.08) introduced deeper than the residual stress of SP(0.8+0.08) is larger in the range of As=1.0-0.3. Since the residual stress in the thickness direction has a greater effect on ahml than the residual stress at the surface, it is necessary to introduce it more deeply. The relation of ahml, a25,50, and aNDI were evaluated in the point for safety and reliability.

Drought Index Development for Agricultural Drought Monitoring in a Catchment (집수역 내 농업가뭄 감시를 위한 가뭄지수 개발)

  • Kim, Dae-Jun;Moon, Kyung-Hwan;Yun, Jin I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.4
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    • pp.359-367
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    • 2014
  • Drought index can be used to implement an early warning system for drought and to operate a drought monitoring service. In this study, an approach was examined to determine agricultural drought index (ADI) at high spatial resolution, e.g., 270 m. The value of ADI was calculated based on soil water balance between supply and demand of water. Water supply is calculated by the cumulative effective precipitation with the application of the weight to the precipitation from two months ago. Water demand is derived from the actual evapotranspiration, which was calculated applying a crop coefficient to the reference evapotranspiration. The amount of surface runoff on a given soil type was also used to calculate soil residual moisture. Presence of drought was determined based on the probability distribution in the given area. In order to assess the reliability of this index, the amount of residual moisture, which represents severity of drought, was compared with measurements of soil moisture at three experimental between July 2012 and December 2013. As a result, the ADI had greater correlation with measured soil moisture compared with the standardized precipitation index, which suggested that the ADI would be useful for drought warning services.

Spectral Infrared Signature Analysis of the Aircraft Exhaust Plume (항공기 배기 플룸의 파장별 IR 신호 해석)

  • Gu, Bonchan;Baek, Seung Wook;Yi, Kyung Joo;Kim, Man Young;Kim, Won Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.8
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    • pp.640-647
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    • 2014
  • Infrared signature of aircraft exhaust plume is the critical factor for aircraft survivability. To improve the military aircraft survivability, the accurate prediction of infrared signature for the propulsion system is needed. The numerical analysis of thermal fluid field for nozzle inflow, free stream flow, and plume region is conducted by using the in-house code. Weighted Sum of Gray Gases Model based on Narrow Band with regrouping is adopted to calculate the spectral infrared signature emitted from aircraft exhaust plume. The accuracy and reliability of the developed code are validated in the one-dimensional band model. It is found that the infrared radiant intensity is relatively more strong in the plume through the analysis, the results show the different characteristic of the spectral infrared signature along the temperature, the partial pressure, and the species distribution. The continuous spectral radiant intensity is shown near the nozzle exit due to the emission from the nozzle wall.

Analysis of Network Traffic with Urban Area Characteristics for Mobile Network Traffic Model (이동통신 네트워크 트래픽 모델을 위한 도시 지역 이동통신 트래픽 특성 분석)

  • Yoon, Young-Hyun
    • The KIPS Transactions:PartC
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    • v.10C no.4
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    • pp.471-478
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    • 2003
  • Traditionally,, analysis, simulation and measurement have all been used to evaluate the performance of network protocols and functional entities that support mobile wireless service. Simulation methods are useful for testing the complex systems which have the very complicate interactions between components. To develop a mobile call simulator which is used to examine, validate, and predict the performance of mobile wireless call procedures must have the teletraffic model, which is to describe the mobile communication environments. Mobile teletraffic model is consists of 2 sub-models, traffic source and network traffic model. In this paper, we analyzed the network traffic data which are gathered from selected Base Stations (BSs) to define the mobile teletraffic model. We defined 4 types of cell location-Residential, Commercial, Industrial, and Afforest zone. We selected some Base Stations (BSs) which are represented cell location types in Seoul city, and gathered real data from them And then, we present the call rate per hour, cail distribution pattern per day, busy hours, loose hours, the maximum number of call, and the minimum number of calls based on defined cell location types. Those parameters are very important to test the mobile communication system´s performance and reliability and are very useful for defining the mobile network traffic model or for working the existed mobile simulation programs as input parameters.

A Study of the Relationship to the Student's Health Behavior, Belief, Value and Health Service Utilization -With Emphasis on Family Structure and Other Variables- (학생(學生)의 건강행위(健康行爲), 신념(信念), 가치(價値) 및 보건의료(保建醫療) 이용(利用)에 미치는 영향(影響)에 관(關)한 연구 -가족(家族)의 형태(形態) 및 제특성(諸特性)을 중심(中心)으로-)

  • Chung, Yeon Kang
    • Journal of the Korean Society of School Health
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    • v.6 no.1
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    • pp.9-44
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    • 1993
  • An explorative and descriptive study in order to determine the effect of family structure and other socio-demographic variables on health behavior, belief, locus, and value and utilization of public health service was carried out. Data were collected from 1,653 subjects randomly sampled in three areas, Seoul, Kyunggi province, and Cheju province. From Seoul 849 subjects were selected, 397 subjects Kyunggi, and 407 subjects from Cheju, respectively. Self-reporting questionaires were administered during the period from March to June, 1992. The major findings were as follows: 1) The subjects visited herb-doctor's at irregular intervals mainly to have tonic medicine prepared. They preferred herb-doctor's rather than with doctors at clinics and hospitals. Statistically significant difference was found among the regions studied (p<0.05). 2) The reason for visiting hospitals was primarily for treatment of diseases. They preferred hospital because they felt that the hospitals offer much highly reliable treatment services as well as medical accessibility. For the purpose of hospital utilization, statistically significant differences existed among sex, educational level, family type and region. However, no significance was found among sex, educational level, and region (p<0.05). 3) The subjects utilized general hospitals mainly for diagnosis and treatment of diseases. They preferred general hospitals because of their much better facilities and reliability. Statistical significance was found among sex, educational level, and region (p<0.05). 4) The subjects visited dentist at irregular intervals basis. They visited once half a year or three to four months. their purpose of visit was mainly for diagnosis and treatment of diseases. Statistical significance differences were found among educational level, region and economic standard (p<0.05). 5) Whenever their illnesses were mild and the pharmacies was located in nearby they visited to pharmacies. They visited once a month and patient medicines. Statistically significant differences were found among sex, educational level and region (p<0.05). 6) The subjects believed that herb medicine was quite efficacious for treatment of some diseases, particularly by information handed down through time-honored tradition and experience. However, they recognized that the efficacy of folk medicine can vary with type and severity of diseases. Statistical significance was among sex, educational level, region and economic standard (p<0.05). 7) The reason why subjects believed that pray and superstition are effective for treatment of certain type of diseases, particularly in neuropathy, was the belief in God's almighty. Statistically significant differences were found among sex, educational level, regions and economic standard (p<0.05). 8) Most of subjects under same condition preferred western medicine because they believed that it is more scientific and prompts in showing therapeutic effect. Statistical significance was not found in the choice of type of public health service among, regions. But significant differences were found among sex, educational level and region (p<0.05). 9) The subjects looked for pharmacy if they thought the symptom was mild. However, they visited hospitals for chronic disease and general hospitals for emergency treatment. Statistical significances were found among educational level, region and economic standard (p<0.05). 10) Although most of students wanted to have a healthy life as for the component of health standard and value, they think that they are not healthy (p<0.05). As for the health behavior, significant difference was found in the proportion of smoking and drinking between educational level and region (p<0.05). The health locus was affected by educational level, and health behavior was influenced by region, sex and educational level. The utilization of type of public health service was influenced by family type and region, and health belief by region and educational level, and the health values by region and economic standard respectively, most of correlation showed statistical significance. Among them, the highest correlation was seen between locus of control and external/internal locus of control, which is quite obvious. The correlation between health belief and behavior was the next highest, but still low (0.343). All the other variables are low but significant except only a few of those. These findings indicate that health education should be incorporated into the curriculum so as to develop desirable health habit, and ability of self-control in accordance with their growth stages. A systematic and scientific understanding on the herb/folk medicine is needed, and greater reliability of the utilization of public health services are is still required. Health policy for equal distribution of health service throughout the country along the hierarchical health service system and complementary mutual assistance and cooperation among various health organizations are also required.

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The Empirical Exploration of the Conception on Nursing (간호개념에 대한 기초조사)

  • 백혜자
    • Journal of Korean Academy of Nursing
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    • v.11 no.1
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    • pp.65-87
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    • 1981
  • The study is aimed at exploring concept held by clinical nurses of nursing. The data were collected from 225 nurses conviniently selected from the population of nurses working in Kang Won province. Findings include. 1) Nurse's Qualification. The respondents view that specialized knowledge is more important qualification of the nurse. Than warm personality. Specifically, 92.9% of the respondents indicated specialized knowledge as the most important qualification while only 43.1% indicated warm personality. 2) On Nursing Profession. The respondents view that nursing profession as health service oriented rather than independent profession specifically. This suggests that nursing profession is not consistentic present health care delivery system nor support nurses working independently. 3) On Clients of Nursing Care The respondents include patients, family and the community residents in the category of nursing care. Specifically, 92.0% of the respondents view that patient is the client, while only 67.1% of nursing student and 74.7% of herself. This indicates the lack of the nurse's recognition toward their clients. 4) On the Priority of Nursing care. Most of the respondents view the clients physical psychological respects as important component of nursing care but not the spiritual ones. Specially, 96.0% of the respondents indicated the physical respects, 93% psychological ones, while 64.1% indicated the spiritual ones. This means the lack of comprehensive conception on nursing aimension. 5) On Nursing Care. 91.6% of the respondents indicated that nursing care is the activity decreasing pain or helping to recover illness, while only 66.2% indicated earring out the physicians medical orders. 6) On Purpose of Nursing Care. 89.8% of the respondents indicated preventing illness and than 76.6% of them decreasing 1;ai of clients. On the other hand, maintaining health has the lowest selection at the degree of 13.8%. This means the lack of nurses' recognition for maintaining health as the most important point. 7) On Knowledge Needed in Nursing Care. Most of the respondents view that the knowledge faced with the spot of nursing care is needed. Specially, 81.3% of the respondents indicated simple curing method and 75.1%, 73.3%, 71.6% each indicated child nursing, maternal nursing and controlling for the communicable disease. On the other hand, knowledge w hick has been neglected in the specialized courses of nursing education, that is, thinking line among com-w unity members, overcoming style against between stress and personal relation in each home, and administration, management have a low selection at the depree of 48.9%,41.875 and 41.3%. 8) On Nursing Idea. The highest degree of selection is that they know themselves rightly, (The mean score measuring distribution was 4.205/5) In the lowest degree,3.016/5 is that devotion is the essential element of nursing, 2.860/5 the religious problems that human beings can not settle, such as a fatal ones, 2,810/5 the nursing profession is worth trying in one's life. This means that the peculiarly essential ideas on the professional sense of value. 9) On Nursing Services. The mean score measuring distribution for the nursing services showed that the inserting of machine air way is 2.132/5, the technique and knowledge for surviving heart-lung resuscitating is 2.892/s, and the preventing air pollution 3.021/5. Specially, 41.1% of the respondents indicated the lack of the replied ratio. 10) On Nurses' Qualifications. The respondents were selected five items as the most important qualifications. Specially, 17.4% of the respondents indicated specialized knowledge, 15.3% the nurses' health, 10.6% satisfaction for nursing profession, 9.8% the experience need, 9.2% comprehension and cooperation, while warm personality as nursing qualifications have a tendency of being lighted. 11) On the Priority of Nursing Care The respondents were selected three items as the most important component. Most of the respondents view the client's physical, spiritual: economic points as important components of nursing care. They showed each 36.8%, 27.6%, 13.8% while educational ones showed 1.8%. 12) On Purpose of Nursing Care. The respondents were selected four items as the most important purpose. Specially,29.3% of the respondents indicated curing illness for clients, 21.3% preventing illness for client 17.4% decreasing pain, 15.3% surviving. 13) On the Analysis of Important Nursing Care Ranging from 5 point to 25 point, the nurses' qualification are concentrated at the degree of 95.1%. Ranging from 3 point to 25, the priorities of nursing care are concentrated at the degree of 96.4%. Ranging from 4 point to 16, the purpose of nursing care is concentrated at the degree of 84.0%. 14) The Analysis, of General Characteristics and Facts of Nursing Concept. The correlation between the educational high level and nursing care showed significance. (P < 0.0262). The correction between the educational low level and purpose of nursing care showed significance. (P < 0.002) The correlation between nurses' working yeras and the degree of importance for the purpose of nursing care showed significance (P < 0.0155) Specially, the most affirmative answers were showed from two years to four ones. 15) On Nunes' qualification and its Degree of Importance The correlation between nurses' qualification and its degree of importance showed significance. (r = 0.2172, p< 0.001) 0.005) B. General characteristics of the subjects The mean age of the subject was 39 ; with 38.6% with in the age range of 20-29 ; 52.6% were male; 57.9% were Schizophrenia; 35.1% were graduated from high school or high school dropouts; 56.l% were not have any religion; 52.6% were unmarried; 47.4% were first admission; 91.2% were involuntary admission patients. C. Measurement of anxiety variables. 1. Measurement tools of affective anxiety in this study demonstrated high reliability (.854). 2. Measurement tools of somatic anxiety in this study demonstrated high reliability (.920). D. Relationship between the anxiety variables and the general characteristics. 1. Relationship between affective anxiety and general characteristics. 1) The level of female patients were higher than that of the male patient (t = 5.41, p < 0.05). 2) Frequencies of admission were related to affective anxiety, so in the first admission the anxiety level was the highest. (F = 5.50, p < 0.005). 2, Relationship between somatic anxiety and general characteristics. 1) The age range of 30-39 was found to have the highest level of the somatic anxiety. (F = 3.95, p < 0.005). 2) Frequencies of admission were related to the somatic anxiety, so .in first admission the anxiety level was the highest. (F = 9.12, p < 0.005) 0. Analysis of significant anxiety symptoms for nursing intervention. 1. Seven items such as dizziness, mental integration, sweating, restlessness, anxiousness, urinary frequency and insomnia, init. accounted for 96% of the variation within the first 24 hours after admission. 2. Seven items such as fear, paresthesias, restlessness, sweating insomnia, init., tremors and body aches and pains accounted for 84% of the variation on the 10th day after admission.

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A study on developing a new self-esteem measurement test adopting DAP and drafting the direction of digitalizing measurement program of DAP (청소년 자존감 DAP 인물화 검사 개발 및 디지털화 측정 시스템 방향성 연구)

  • Woo, Sungju;Park, Chongwook
    • Journal of the HCI Society of Korea
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    • v.8 no.1
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    • pp.1-9
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    • 2013
  • This is to develop a new way of testing self-esteem by adopting DAP(Draw a Person) test and to make a platform to digitalize it for young people in the adolescent stage. This approach is to get high effectiveness of the self-esteem measurement using DAP test, including some personal inner situations which can be easily missed in the large statistical analysis. The other objective of this study is digitalize to recover limits of DAP test in the subjective rating standard. It is based on the distribution of the figure drawing expressed numerically by the anxiety index of Handler. For these two examinations, we made experiment through 4 stages with second grade middle school 73 students from July 30th to October 31th in 2009 during 4 months. Firstly, we executed 'Self Values Test' for all 73 people, and divided them into two groups; one is high self-esteem group of 36 people, the other is low self-esteem group of 37 people. Secondly, we regrouped them following D (Depression), Pd (Psychopathic Deviate), Sc (Schizophrenia) scales of MMPI; one is high self-esteem group of 7 people, the other is low self-esteem group of 13 people. Thirdly, we conducted DAP test separately for these 20 people. We intended to verify necessity and appropriateness of direction of 'Digitalizing Measurement System' by comparing and analyzing relation between DAP and Self-esteem following evaluation criteria which has similarity in 3 tests, after executing DAP to reflect peculiarity of adolescents sufficiently. We compared and analyzed result abstracted by sampling DAP test of two groups; One is high self-esteem group of 2 people, the other is low self-esteem group of 2 people; to confirm whether we can improve limitation that original psychological testing has by comparing mutual reliance of measurement test. Finally, with DAP test gained from correlations between self-esteem and melancholia following as above-mentioned steps, we discovered possibility of realization to get a concrete and individual criteria of evaluation based on Expert System as a way of enhancing accessibility in quantitative manner. 'Digitalizing Measurement Program' of DAP test suggested in this study promote results' reliability based on existing tests and measurement.

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Antecedents of Trust and Effects on Committment in B2B e-Marketplace (B2B 마켓플레이스에서 신뢰의 선행요인과 몰입에 미치는 영향)

  • Oh, Sang-Hyun;Kim, Sang-Hyeon
    • Journal of Distribution Research
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    • v.13 no.1
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    • pp.1-33
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    • 2008
  • As the interest in the business-to-business(B2B) electronic commerce is increasing, many companies are participating in the B2B e-Marketplaces. The e-Marketplace is defined as the virtual market that many players take part in to transact. The e-Marketplace has an influenced on the manner in which organizational buyers and sellers interact. As a result, it is important to develop an understanding of the behaviors of firms that use these electronic marketplaces. The purpose of this study is to develop a comprehensive model for trust and commitment of B2B e-Marketplace and empirically to examine their structural relationships. Drawing from trust and commitment theory in the interorganizational relationship and B2B electronic commerce context, this study identifies network externality, interactivity, justice, quality of information sharing, institutional assurance as the determinants of trust and commitment of e-Marketplace. The proposed model hypothesized that (1) trust is a function of network externality, interactivity, justice, quality of information sharing, institutional assurance, (2) attitudinal and behavioral commitment is a function of trust, (3) behavioral commitment is a function of attitudinal commitment. The proposed model is tested using organizational-level survey data from 187 buying organizations that conduct business in MRO e-Marketplaces. The data were tested by reliability test, correlation analysis, exploratory factor analysis, confirmatory factor analysis and covariance structure analysis. The results indicate that (1) trust is influenced by network externality, interactivity, justice, institutional assurance, (2) attitudinal commitment and behavioral commitment is influenced by trust (3) behavioral commitment is influenced by attitudinal commitment. Also, the empirical results confirmed that trust play a strong, central role in determinging e-Marketplace commitment. The key theoretical contribution of this research is that it begins to extend interorganizational information system literature in areas such as B2B Internet e-Marketplace. Managerially, this study contributes tn the understanding of the role of B2B e-Markeplace providers in Internet situation. And Limitations of this study and guidelines for future researches are also discussed.

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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 2008 (설비공학 분야의 최근 연구 동향: 2008년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.12
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    • pp.715-732
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    • 2009
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. 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) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.