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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 2012 (설비공학 분야의 최근 연구 동향 : 2012년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwataik;Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Choi, Jong Min;Park, Jun-Seok;Kim, Sumin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.6
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    • pp.346-361
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    • 2013
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2012. 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. The conclusions are as follows : (1) The research works on thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and valves, fuel cells and power plants, ground-coupled heat pumps, and general heat and mass transfer systems. Research issues are mainly focused on new and renewable energy systems, such as fuel cells, ocean thermal energy conversion power plants, and ground-coupled heat pump systems. (2) Research works on the 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 natural convection in a square enclosure with two hot circular cylinders, non-uniform grooved tube considering tube expansion, single-tube annular baffle system, broadcasting LED light with ion wind generator, mechanical property and microstructure of SA213 P92 boiler pipe steel, and flat plate using multiple tripping wires. In the area of pool boiling and condensing heat transfer, researches on the design of a micro-channel heat exchanger for a heat pump, numerical simulation of a heat pump evaporator considering the pressure drop in the distributor and capillary tubes, critical heat flux on a thermoexcel-E enhanced surface, and the performance of a fin-and-tube condenser with non-uniform air distribution and different tube types were actively carried out. In the area of industrial heat exchangers, researches on a plate heat exchanger type dehumidifier, fin-tube heat exchanger, an electric circuit transient analogy model in a vertical closed loop ground heat exchanger, heat transfer characteristics of a double skin window for plant factory, a regenerative heat exchanger depending on its porous structure, and various types of plate heat exchangers were performed. (3) In the field of refrigeration, various studies were executed to improve refrigeration system performance, and to evaluate the applicability of alternative refrigerants and new components. Various topics were presented in the area of refrigeration cycle. Research issues mainly focused on the enhancement of the system performance. In the alternative refrigerant area, studies on CO2, R32/R152a mixture, and R1234yf were performed. Studies on the design and performance analysis of various compressors and evaporator were executed. (4) In building mechanical system research fields, twenty-nine studies were conducted to achieve effective design of mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, renewable energy systems, and lighting systems in buildings. New designs and performance tests using numerical methods and experiments provide useful information and key data, which can improve the energy efficiency of buildings. (5) In the fields of the architectural environment, studies for various purposes, such as indoor environment, building energy, and renewable energy were performed. In particular, building energy-related researches and renewable energy systems have been mainly studied, reflecting interests in global climate change, and efforts to reduce building energy consumption by government and architectural specialists. In addition, many researches have been conducted regarding indoor environments.

A Theoretical Review of Basin Storage Coefficient and Concentration Time Using the Nash Model (Nash 모형을 이용한 유역 저류상수 및 집중시간의 이론적 검토)

  • Yoo, Chul-Sang
    • Journal of Korea Water Resources Association
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    • v.42 no.3
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    • pp.235-246
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    • 2009
  • This study theoretically reviews the basin storage coefficient and concentration time using the Nash model, a simple unit hydrograph theory. First, the storage coefficient and concentration time of Nash instantaneous unit hydrograph (IUH) are derived based on their definitions, whose characteristics as well as their relationship are also reviewed. Additionally, several empirical equations of storage coefficient and concentration time commonly used in Korea are evaluated by comparing them with those for the Nash IUH. Major results of this study are summarized as follows. (1) The concentration time of Nash IUH is approximately linearly proportional to the number of linear reservoirs, but the storage coefficient non-linearly to the square root. That is, if increasing the number of linear reservoirs by four times, the concentration time becomes also increased by about four times, but the storage coefficient only about two times. This result has a special meaning to understand the effect of basin subdivision on the concentration time and storage coefficient. (2) The storage coefficient and concentration time of Nash IUH are not independent each other, so their independent estimation does not make any physical sense. As the concentration time among the two is more sensitive to the number of linear reservoirs, which should be estimated first, then the storage coefficient considering the concentration time estimated. (3) Empirical equations of concentration time can be divided into two groups, one following the linear channel theory and the other not, whose equation forms are also found to be very similar. This result indicates that the characteristic factors dominating the concentration time are very similar, indicating the possibility of its regionalization over a basin with consistent equation forms. (4) Those for storage coefficient like the Russell formulae are found to consider the physical characteristics of a basin, so their unreasonable applications could sufficiently be excluded.

Characteristics of Springtime Temperature Within Mt. Youngmun Valley (용문산 산악지역의 봄철 기온특성)

  • Chun, Ji Min;Kim, Kyu Rang;Lee, Seon-Yong;Kang, Wee Soo;Choi, Jong Mun;Hong, Soon Sung;Park, Jong-Seon;Park, Eun-U;Kim, Yong Sam;Choi, Young-Jean;Jung, Hyun-Sook
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.1
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    • pp.39-50
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    • 2014
  • This paper reviews the results of recent observations in the Yeonsuri valley of Mt. Youngmun during springtime (March to May) in 2012. Automated weather stations were installed at twelve sites in the valley to measure temperature and 2, 3 dimensional wind. We examined temporal and spatial characteristics of temperatures and wind data. The Yeonsuri valley springtime average temperature lapse rate between the top and bottom of the entire period is $-0.44^{\circ}C/100$ m. It can be changed by the synoptic weather conditions, the lapse rates is greatest in order of clear days ($-0.48^{\circ}C/100$ m), rainy ($-0.41^{\circ}C/100$ m) and cloudy days ($-0.40^{\circ}C/100$ m). In the night, the temperature inversion layer (thermal belt) and the cold pool are formed within the valley. In addition, we measured temperature and wind distribution from the bottom to 3.5 m, the cold layers existed up to 1.5 m, which were affected by ground mixed layer. The results will provide useful guidance on agricultural practices as well as model simulations.

The Haptic Perception Aspect shown in Landscape Architecture before Modernism - Focused on Historical Development Process - (모더니즘 이전 조경에 나타난 촉지적 지각 양상 - 역사적 전개 과정을 중심으로 -)

  • Kim, Jin-Seob;Kim, Jin-Seon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.4
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    • pp.1-14
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    • 2015
  • In the West, of the body's five senses sight is considered the most important but Ocular-centralistic thinking contains many issues. Privileging the subject and inhibiting interaction with the other senses, Ocular-centrism limits the experience of the world to the visual area. However, experiences can be understood as 'touching' various forms and are related to touch. With the heightened interest in the multi-sensuous side of the body contrary to Ocular-centrism, the intervention of the body in the external space has become an important issue in modern landscape architecture. This study explores the possibility of the haptic perception system that causes the active experience of a subject. Haptic perception plays a catalytic role leading an active experience of the subject and the subject experiences a sense of place through such haptic perception. By revealing what was known through the sense of touch through the concurrency and interaction of the various senses, haptic perception draws active participation The haptic perception system has been studied in various fields but has not been studied in the field of landscape architecture. Thus, this study discusses the aspect of haptic perception limited to landscape architecture shown before modernism. In a discussion on haptic perception, the concept of haptic perception is clarified through previous study reviews and literature and the characteristics of haptic perception are derived. Then, the problems of the Ocular-centrism system and the need for haptic perception are discussed. In the historical development process of haptic perception, the change process of the scopic regime is examined chronologically and the ways in which Ocular-centralistic thinking and anti-Ocular-centralistic thinking have been projected on the architecture and landscape architecture of each age are studied via literature and cases studies. The impact of the scopic regime on the landscape architecture field in the historical change process is examined.

A Study of a Teaching Plan for Gifted Students in Elementary School Mathematics Classes (일반학급에서의 초등 수학 영재아 지도 방안 연구)

  • Kim, Myeong-Ja;Shin, Hang-Kyun
    • Journal of Elementary Mathematics Education in Korea
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    • v.13 no.2
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    • pp.163-192
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    • 2009
  • Currently, our country operates gifted education only as a special curriculum, which results in many problems, e.g., there are few beneficiaries of gifted education, considerable time and effort are required to gifted students, and gifted students' educational needs are ignored during the operation of regular curriculum. In order to solve these problems, the present study formulates the following research questions, finding it advisable to conduct gifted education in elementary regular classrooms within the scope of the regular curriculum. A. To devise a teaching plan for the gifted students on mathematics in the elementary school regular classroom. B. To develop a learning program for the gifted students in the elementary school regular classroom. C. To apply an in-depth learning program to gifted students in mathematics and analyze the effectiveness of the program. In order to answer these questions, a teaching plan was provided for the gifted students in mathematics using a differentiating instruction type. This type was developed by researching literature reviews. Primarily, those on characteristics of gifted students in mathematics and teaching-learning models for gifted education. In order to instruct the gifted students on mathematics in the regular classrooms, an in-depth learning program was developed. The gifted students were selected through teachers' recommendation and an advanced placement test. Furthermore, the effectiveness of the gifted education in mathematics and the possibility of the differentiating teaching type in the regular classrooms were determined. The analysis was applied through an in-depth learning program of selected gifted students in mathematics. To this end, an in-depth learning program developed in the present study was applied to 6 gifted students in mathematics in one first grade class of D Elementary School located in Nowon-gu, Seoul through a 10-period instruction. Thereafter, learning outputs, math diaries, teacher's checklist, interviews, video tape recordings the instruction were collected and analyzed. Based on instruction research and data analysis stated above, the following results were obtained. First, it was possible to implement the gifted education in mathematics using a differentiating instruction type in the regular classrooms, without incurring any significant difficulty to the teachers, the gifted students, and the non-gifted students. Specifically, this instruction was effective for the gifted students in mathematics. Since the gifted students have self-directed learning capability, the teacher can teach lessons to the gifted students individually or in a group, while teaching lessons to the non-gifted students. The teacher can take time to check the learning state of the gifted students and advise them, while the non-gifted students are solving their problems. Second, an in-depth learning program connected with the regular curriculum, was developed for the gifted students, and greatly effective to their development of mathematical thinking skills and creativity. The in-depth learning program held the interest of the gifted students and stimulated their mathematical thinking. It led to the creative learning results, and positively changed their attitude toward mathematics. Third, the gifted students with the most favorable results who took both teacher's recommendation and advanced placement test were more self-directed capable and task committed. They also showed favorable results of the in-depth learning program. Based on the foregoing study results, the conclusions are as follows: First, gifted education using a differentiating instruction type can be conducted for gifted students on mathematics in the elementary regular classrooms. This type of instruction conforms to the characteristics of the gifted students in mathematics and is greatly effective. Since the gifted students in mathematics have self-directed learning capabilities and task-commitment, their mathematical thinking skills and creativity were enhanced during individual exploration and learning through an in-depth learning program in a differentiating instruction. Second, when a differentiating instruction type is implemented, beneficiaries of gifted education will be enhanced. Gifted students and their parents' satisfaction with what their children are learning at school will increase. Teachers will have a better understanding of gifted education. Third, an in-depth learning program for gifted students on mathematics in the regular classrooms, should conform with an instructing and learning model for gifted education. This program should include various and creative contents by deepening the regular curriculum. Fourth, if an in-depth learning program is applied to the gifted students on mathematics in the regular classrooms, it can enhance their gifted abilities, change their attitude toward mathematics positively, and increase their creativity.

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A Study on How Reading Comic Books Affects Creativity (만화 읽기가 창의력 향상에 미치는 연구)

  • Jang, Jin-Young;Park, Hye-Ri
    • Cartoon and Animation Studies
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    • s.36
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    • pp.437-467
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    • 2014
  • This study is intended to reveal reading comic books helps improve creativity. Though the long-lasting negative recognition towards comic books has positively changed these days, we need a ground upon which the social recognition needs improvement in that children's comic books have been used as a learning tool. Its introduction points out that there has been shortage of empirical researches on comic book reading, and as one of the empirical research methods, presents a method of comparative analysis on comic book reading, school study, and creativity tests via survey. The theoretical background in the 2nd chapter, first, puts emphasis on the significance of the creativity theory among all the other theories related to creativity, which focuses on problem-solving capacity. Second, it theoretically reviews the meaning which 'fun' and 'interest' have in development of creativity in the context of developmental process of the modern educational theories. Third, it empathizes that traits of reading comic books start off with 'fun' and 'interest', that awareness of reality gets expanded via the process of characters making their way through a strange world with empathy and absorption, and that comic book reading has to do with creativity. Fourth, it presents a model questionnaire with which to study relationship between comic books and creativity in an empirical way. The analysis on the survey outcome in the 3rd chapter shows, first, that smart students read many comic books, not to mention that studying helps improve creativity, which indicates above all, comic book reading and improvement of creativity are not negatively related, but are mutually complementary. Second, that creativity enhanced by reading comic books is higher than that enhanced by studying, which may mean comic book reading is more effective than studying in developing creativity. It has drawn a conclusion based upon these results, that reading comic books bears positive efficacy on both studying and developing creativity. Standing on this conclusion, it proposes it necessary to develop methods by grades of educating how to read comic books and to provide a recommended list of comic books to read.

Detection of Phantom Transaction using Data Mining: The Case of Agricultural Product Wholesale Market (데이터마이닝을 이용한 허위거래 예측 모형: 농산물 도매시장 사례)

  • Lee, Seon Ah;Chang, Namsik
    • Journal of Intelligence and Information Systems
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    • v.21 no.1
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    • pp.161-177
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    • 2015
  • With the rapid evolution of technology, the size, number, and the type of databases has increased concomitantly, so data mining approaches face many challenging applications from databases. One such application is discovery of fraud patterns from agricultural product wholesale transaction instances. The agricultural product wholesale market in Korea is huge, and vast numbers of transactions have been made every day. The demand for agricultural products continues to grow, and the use of electronic auction systems raises the efficiency of operations of wholesale market. Certainly, the number of unusual transactions is also assumed to be increased in proportion to the trading amount, where an unusual transaction is often the first sign of fraud. However, it is very difficult to identify and detect these transactions and the corresponding fraud occurred in agricultural product wholesale market because the types of fraud are more intelligent than ever before. The fraud can be detected by verifying the overall transaction records manually, but it requires significant amount of human resources, and ultimately is not a practical approach. Frauds also can be revealed by victim's report or complaint. But there are usually no victims in the agricultural product wholesale frauds because they are committed by collusion of an auction company and an intermediary wholesaler. Nevertheless, it is required to monitor transaction records continuously and to make an effort to prevent any fraud, because the fraud not only disturbs the fair trade order of the market but also reduces the credibility of the market rapidly. Applying data mining to such an environment is very useful since it can discover unknown fraud patterns or features from a large volume of transaction data properly. The objective of this research is to empirically investigate the factors necessary to detect fraud transactions in an agricultural product wholesale market by developing a data mining based fraud detection model. One of major frauds is the phantom transaction, which is a colluding transaction by the seller(auction company or forwarder) and buyer(intermediary wholesaler) to commit the fraud transaction. They pretend to fulfill the transaction by recording false data in the online transaction processing system without actually selling products, and the seller receives money from the buyer. This leads to the overstatement of sales performance and illegal money transfers, which reduces the credibility of market. This paper reviews the environment of wholesale market such as types of transactions, roles of participants of the market, and various types and characteristics of frauds, and introduces the whole process of developing the phantom transaction detection model. The process consists of the following 4 modules: (1) Data cleaning and standardization (2) Statistical data analysis such as distribution and correlation analysis, (3) Construction of classification model using decision-tree induction approach, (4) Verification of the model in terms of hit ratio. We collected real data from 6 associations of agricultural producers in metropolitan markets. Final model with a decision-tree induction approach revealed that monthly average trading price of item offered by forwarders is a key variable in detecting the phantom transaction. The verification procedure also confirmed the suitability of the results. However, even though the performance of the results of this research is satisfactory, sensitive issues are still remained for improving classification accuracy and conciseness of rules. One such issue is the robustness of data mining model. Data mining is very much data-oriented, so data mining models tend to be very sensitive to changes of data or situations. Thus, it is evident that this non-robustness of data mining model requires continuous remodeling as data or situation changes. We hope that this paper suggest valuable guideline to organizations and companies that consider introducing or constructing a fraud detection model in the future.

Critiques of 'The Endangered and Protected Wild Species List in Korea' Proposed by Korea Ministry of Environment and Listing Process - Is This the Best Process for the Current National Management of Endangered Wildlife and Plants in Korea? - (2011년 환경부 멸종위기종 등록절차 및 대상 멸종위기종 식물 목록 재고-과연 현재 국가 멸종위기종 관리가 최선의 방안인가? -)

  • Kim, Hui;Lee, Byong Cheon;Kim, Yong Shik;Chang, Chin-Sung
    • Journal of Korean Society of Forest Science
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    • v.101 no.1
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    • pp.7-19
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    • 2012
  • After having announced legislation for threatened or endangered species on the List of Endangered and Threatened Wildlife and Plants in 2005, the Korea Ministry of Environment proposed (in June 2011) amending the list, thereby delisting or reclassifying endangered species using new quantitative criteria for two levels (I and II), as well as status reviews. The new legislation included 40 species remained in their original endangered status, but 19 species were delisted, 5 species were proposed as candidates for delisting, 29 species were given a new endangered listing, and 3 species were proposed for an endangered listing in Korea. We assessed the threatened status of 98 plants using the IUCN Red List Criteria (version 3.1) at the global level, and compared the Ministry's revised criteria with the IUCN Red List Criteria and ESA criteria used in the USA. Most species proposed by the Ministry do not qualify as threatened and one of the major difficulties found in applying IUCN Red List Criteria at the global scale was a lack of knowledge on the status of species at broader geographic scales and the perceived difficulty this causes. Under the current classification process, many endangered species, such as Abeliophyllum distichum, Leontice microrhyncha, Echinosophora koreensis, Leontopodium coreanum, Iris odaesanensis, and Corylopsis coreana at global level were excluded here. Knowledge gaps and uncertainties mean that the number of taxa at high risk of extinction may be substantially greater than is currently understood. Due to a lack of information on its taxonomic status, currently there is controversy over the Red List status of Physocarpus insularis. Also, Caragana koreana, which was an invalidly published name, should be excluded here. Although the Korea Ministry of Environment insisted this procedure was conducted by applying the modified IUCN threat categories and definitions, this evaluation has been carried out based only on subjective views and misapplication of the IUCN Red List Criteria. The current listings by the Korea Ministry of Environment should be challenged. We suggest that broad species concepts on endemic species are applied and also criteria that adequately address the proper quantitative knowledge should be used. It is suggested that the highest priorities for the Red List should be given to endemic species at least in the Korean peninsula first at global scale.

Requirements and Self-evaluation of Competencies Necessary to be Effective Nutrition Teachers Perceived by School Food Service Dieticians (학교급식 영양사가 인식하는 효과적인 영양교사의 역량 요구도와 자기 평가)

  • Lee, Kyung-Eun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.5
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    • pp.626-635
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    • 2009
  • The purposes of the study were to identify a comprehensive competency list related to the jobs of nutrition teachers and to compare the competency needs for nutrition teachers and dieticians' competency levels. Job functional areas and a competency list for nutrition teachers were developed based on a review of literature and revised through expert panel reviews. A total of 53 competency statements associated with 11 job functional areas were specified. Questionnaires were distributed to 457 dieticians engaged in school food service and 148 responses were returned (response rate: 32.4%). Excluding incomplete responses, 142 questionnaires were used for data analysis. Approximately half of the respondents were enrolled in an 1-year nutrition teacher certificate program, 25% in a graduate school of nutrition education, and 19% had completed an 1-year nutrition teacher certificate program. The dieticians highly rated requirements of the competencies related to sanitation and employee safety, nutrition counseling, nutrition education, and teaching practices; in contrary, their competency levels for nutrition education, nutrition counseling, and teaching practices were low. Respondents' competency levels were significantly lower than the required competency levels of effective nutrition teachers in all functional areas. A quadratic analysis based on the requirement and self-evaluation of the competencies revealed that priorities of education programs targeting school nutrition teachers or students preparing to be nutrition teachers should be placed on improving competencies related to nutrition education, nutrition counseling, teaching practices, sanitation and employee safety, menu management, and human resource management. These results can be used to develop curriculum materials for basic and continuing professional education for nutrition teachers. It is necessary to review and update competencies regularly to reflect environmental changes in school food service programs.

Twelve Years of Experience with Vascular Ring Surgery (혈관륜 수술의 12년 경험 보고)

  • Kim, Yun-Seok;Goo, Hyun-Woo;Jhang, Won-Kyoung;Yun, Tae-Jin;Seo, Dong-Man;Park, Jeong-Jun
    • Journal of Chest Surgery
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    • v.42 no.6
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    • pp.749-756
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    • 2009
  • Background: Vascular ring is a rare anomaly of the aortic arch. We did surgical repair procedures on 16 cases of vascular ring over the past 12 years. This article reviews our results. Material and Method: Between 1995 and 2007, 16 patients (5 with double aortic arch, 7 with right aortic arch-left ligamentum, 4 with pulmonary artery sling) underwent surgical repair. Mean age at the time of the operation were as follows: double aortic arch, $5.7{\pm}5.5$ years; right aortic arch-left ligamentum, $6.1{\pm}13.4$ years; pulmonary artery sling, $2.9{\pm}2.6$ years. Five patients (71%) with right aortic arch-left ligamentum had an associated Kommerell's diverticulum. Two patients (40%) with double aortic arch, 2 patients (28.6%) with right aortic arch-left ligament and 4 patients (100%) with pulmonary artery sling had associated airway stenosis. Cardiac anomalies were present in 8 of 16 patients. Result: There was no peri-operative or post-operative mortality. The mean hospital stay was $27.1{\pm}38.2$ days. None of our patients underwent reoperation. Conclusion: Vascular ring is rare, but, it needs surgical correction. It is important to suspect the diagnosis and to validate with echocardiography. Preoperative and postoperative computed tomography and bronchoscopy are useful to evaluate the airway and surrounding structures.