• Title/Summary/Keyword: Operational Control

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The Development and Application of Standard Diagnostic Table for Mountain Ginseng Management (산양삼 경영 표준진단표의 개발 및 현지 적용)

  • Jeon, Jun-Heon;Lee, Seong-Youn;Lee, Jung-Min;Ji, Dong-Hyun;Kim, Yeon-Tae;Kang, Kil-Nam
    • Journal of Korean Society of Forest Science
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    • v.103 no.4
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    • pp.622-629
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    • 2014
  • This study aims to develop a standard diagnostic table for mountain ginseng so that the cultivators not only can check their current level of management with the table, but also can understand and address operational challenges better by themselves utilizing the table. The standard diagnostic table consists of 3 categories and 18 subcategories to diagnose the general status of forestry households, the indicators of management performance and the level of management. To develop the table, the study conducted a survey on the actual condition of management, targeting 81 forestry households throughout 15 municipalities including Mu-ju, Jeollabukdo, and Ham-yang, Gyeongsangnamdo, all of which are the chief producing districts of mountain ginseng. Then, the study calculated total scores by regions by aggregating the scores of 18 subcategories, in order to evaluate and compare the management level among regions based on the scores. According to the result, the average score of 81 forestry households was 57.2 point-58% of which surveyed belonged to the range of 40-60 point. Compared by regions, the average score of Jeollabukdo regions was 52.9 point, the lowest, and that of Gyeongsangnamdo regions was 61.4 point, the highest. It is remarkable that among the indicators of management base, the average score of 'mounding (the height of mound)' item was recorded rather low with 1.59 point, reflecting the fact that the cultivators tend to raise mountain ginseng with no additional mounds. As for the indicators of production skills, the average score of the pest control item was remarkably low with 1.28 point. Over 90% of cultivators answered that they do not usually forecast or survey the pest disease in advance. Meanwhile, it is also noticeable that the item of sowing and planting methods, and the item of seed were both rather high, recording 4.00 and 4.47 point respectively. As for the item of management and sales skill, however, the score was rather low with 2.20 point, meaning that the forestry households still have a low interest in the business management.

Fate of Heavy Metals in Activated Sludge: Sorption of Heavy Metal ions by Nocardia amarae

  • Kim, Dong-wook
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 1998.10a
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    • pp.2-4
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    • 1998
  • Proliferation of Nocardia amarae cells in activated sludge has often been associated with the generation of nuisance foams. Despite intense research activities in recent years to examine the causes and control of Nocardia foaming in activated sludge, the foaming continued to persist throughout the activated sludge treatment plants in United States. In addition to causing various operational problems to treatment processes, the presence of Nocardia may have secondary effects on the fate of heavy metals that are not well known. For example, for treatment plants facing more stringent metal removal requirements, potential metal removal by Nocardia cells in foaming activated sludge would be a welcome secondary effect. In contrast, with new viosolid disposal regulations in place (Code o( Federal Regulation No. 503), higher concentration of metals in biosolids from foaming activated sludge could create management problems. The goal of this research was to investigate the metal sorption property of Nocardia amarae cells grown in batch reactors and in chemostat reactors. Specific surface area and metal sorption characteristics of N. amarae cells harvested at various growth stages were compared. Three metals examined in this study were copper, cadmium and nickel. Nocardia amarae strain (SRWTP isolate) used in this study was obtained from the University of California at Berkeley. The pure culture was grown in 4L batch reactor containing mineral salt medium with sodium acetate as the sole carbon source. In order to quantify the sorption of heavy metal ions to N amarae cell surfaces, cells from the batch reactor were harvested, washed, and suspended in 30mL centrifuge tubes. Metal sorption studies were conducted at pH 7.0 and ionlc strength of 10-2M. The sorption Isotherm showed that the cells harvested from the stationary and endogenous growth phase exhibited significantly higher metal sorption capacity than the cells from the exponential phase. The sequence of preferential uptake of metals by N. amarae cells was Cu>Cd>Ni. The specific surFace area of Nocardia cells was determined by a dye adsorption method. N.amarae cells growing at ewponential phase had significantly less specific surface area than that of stationary phase, indicating that the lower metal sorption capacity of Nocardia cells growing at exponential phase may be due to the lower specific surface area. The growth conditions of Nocardia cells in continuous culture affect their cell surface properties, thereby governing the adsorption capacity of heavy metal. The comparison of dye sorption isotherms for Nocardia cells growing at various growth rates revealed that the cell surface area increased with increasing sludge age, indicating that the cell surface area is highly dependent on the steady-state growth rate. The highest specific surface area of 199m21g was obtained from N.amarae cell harvested at 0.33 day-1 of growth rate. This result suggests that growth condition not only alters the structure of Nocardia cell wall but also affects the surface area, thus yielding more binding sites of metal removal. After reaching the steady-state condition at dilution rate, metal adsorption isotherms were used to determine the equilibrium distributions of metals between aqueous and Nocardia cell surfaces. The metal sorption capacity of Nocardia biomass harvested from 0.33 day-1 of growth rate was significantly higher than that of cells harvested from 0.5- and 1-day-1 operation, indicatng that N.amarae cells with a lower growth rate have higher sorpion capacity. This result was in close agreement with the trend observed from the batch study. To evaluate the effect of Nocardia cells on the metal binding capacity of activated sludge, specific surface area and metal sorption capacity of the mixture of Nocardia pure cultures and activated sludge biomass were determined by a series of batch experiments. The higher levels of Nocardia cells in the Nocardia-activated sludge samples resulted in the higher specific surface area, explaining the higher metal sorption sites by the mixed luquor samples containing greater amounts on Nocardia cells. The effect of Nocardia cells on the metal sorption capacity of activated sludge was evaluated by spiking an activated sludge sample with various amounts of pre culture Nocardia cells. The results of the Langmuir isotherm model fitted to the metal sorption by various mixtures of Nocardia and activated sludge indicated that the mixture containing higher Nocardia levels had higher metal adsorption capacity than the mixture containing lower Nocardia levels. At Nocardia levels above 100mg/g VSS, the metal sorption capacity of activate sludge increased proportionally with the amount of Noeardia cells present in the mixed liquor, indicating that the presence of Nocardia may increase the viosorption capacity of activated sludge.

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Application of an empirical method to improve radar rainfall estimation using cross governmental dual-pol. radars (범부처 이중편파레이더의 강우 추정 향상을 위한 경험적 방법의 적용)

  • Yoon, Jungsoo;Suk, Mi-Kyung;Nam, Kyung-Yeub;Park, Jong-Sook
    • Journal of Korea Water Resources Association
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    • v.49 no.7
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    • pp.625-634
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    • 2016
  • Three leading agencies under different ministries - Korea Meteorological Administration (KMA) in the ministry of Environment, Han river control office in the Ministry of Land, Infrastructure and Transport (MOLIT) and Weather Group of ROK Air Force in the Ministry of National Defense (MND) - have been operated radars in the purpose of observing weather, hydrology and military operational weather in Korea. Eight S-band dual-pol. radars have been newly installed or replaced by these ministries over different places by 2015. However each ministry has different aims of operating radars, observation strategies, data processing algorithms, etc. Due to the differences, there is a wide level of accuracy on observed radar data as well as the composite images made of the cross governmental radar measurement. Gaining fairly high level of accuracy on radar data obtained by different agencies has been shared as a great concern by the ministries. Thus, "an agreement of harmonizing weather and hydrological radar products" was made by the three ministries in 2010. Particularly, this is very important to produce better rainfall estimation using the cross governmental radar measurement. Weather Radar Center(WRC) in KMA has been developed an empirical method using measurements observed by Yongin testbed radar. This study is aiming to examine the efficiency of the empirical method to improve the accuracies of radar rainfalls estimated from cross governmental dual-pol. radar measurements. As a result, the radar rainfalls of three radars (Baengnyeongdo, Biseulsan, and, Sobaeksan Radar) were shown improvement in accuracy (1-NE) up to 70% using data from May to October in 2015. Also, the range of the accuracies in radar rainfall estimation, which were from 30% to 60% before adjusting polarimetric variables, were decreased from 65% to 70% after adjusting polarimetric variables.

Technical Standards and Safety Review of the Low and Intermediate Level Radioactive Waste Disposal Facility (중.저준위 방사성폐기물 처분시설에 대한 기술기준 및 안전심사)

  • Cheong, Jae-Hak;Lee, Kwan-Hee;Lee, Yun-Keun;Jeong, Chan-Woo;Rho, Byung-Hwan
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.6 no.4
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    • pp.357-368
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    • 2008
  • On July 31, 2008, the Government issued the construction and operation permit for the first low and intermediate level radioactive waste disposal facility in the Republic of Korea. In this paper, the fundamental regulatory framework, regulatory requirements and technical standards of the disposal facility are introduced, and the phased review process adopted for evaluation of the safety of the facility is briefly described. The Atomic Energy Act sets forth a stepwise regulatory framework for the whole life-cycle of the disposal facility such as siting, design, construction, operation, closure and institutional control. More detailed regulatory requirements and technical standards are stipulated in the subsequent regulations of the Atomic Energy Act and a series of Notices issued by the Ministry of Eduction, Science and Technology. The Korea Institute of Nuclear Safety, as entrusted by the Ministry under the Atomic Energy Act, conducted safety review on the disposal facility, and evaluated the compliance with relevant criteria in all technical elements(i.e. siting and structural safety, radiological environmental impact, operational safety, systems and components, quality assurance, and total systematic performance assessment, etc.). The overall safety review process can be phased into inception phase, initial review phase, main review phase and completion phase. The review results were reported to and deliberated by the five Sub-committees of the Special Committee on Nuclear Safety, and then reported to the Ministry. The Ministry issued the construction and operation permit of the disposal facility through the deliberation of the review results by the Nuclear Safety Commission. Hereafter, the safety of the repository will be reassured by a series of subsequent regulatory inspections and reviews under the Atomic Energy Act. In addition, the licensee's continuous implementation of the "Safety Promotion Plan" may also enhance the long-term safety of the repository and contribute to build-up the confidence of the safety case.

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COATED PARTICLE FUEL FOR HIGH TEMPERATURE GAS COOLED REACTORS

  • Verfondern, Karl;Nabielek, Heinz;Kendall, James M.
    • Nuclear Engineering and Technology
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    • v.39 no.5
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    • pp.603-616
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    • 2007
  • Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

A Study on the Compensatory Education for the Disadvantaged Children in Preschool Age (Focussed on the Programs of Compensatory Education in the U.S.A. and Japan) (불리(不利)한 환경(環境)의 학령전(學齡前) 아동(兒童)을 위한 보상교육(補償敎育)에 관(關)한 연구(硏究) - 미국(美國) 및 일본(日本)의 보상교육(補償敎育)·프로그램을 중심(中心)으로 -)

  • Chong, Young-Sook;Lee, Hee-Ja
    • Korean Journal of Child Studies
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    • v.1
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    • pp.65-81
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    • 1980
  • This study is aimed at investigating the compensatory education which was already implemented or is being implemented in the U.S.A. and Japan; and at studying the types of programs and their characteristics; and at sounding out the possibilities of the application of such programs in family and social conditions is Korea. In order to achieve the above mentioned objectives, the established items for the study are as follows: (1) Various types of early children's education (2) Programs of compensatory education for the disadvantaged Children (3) Head Start Program, Early Training Project and Montessori School (4) Integrated Preschool Programs (5) Day-Care Center for employed mothers We investigated the various compensatory education programs for the preschool children who are in economically, socially, culturally disadvantaged conditions. Head Start Programs were federally supported programs for preschool children and opened as summer programs in 1965 for the first time. The purpose of Head Start has been to give preschool children the kinds of experiences they need in preparation for school. The Head Start children were found to be significantly better prepared for school than the normal children. However, after six to eight months, their initial advantages had virtually. disappeared and then the simple problem with Head Start and other such programs was that little long-term good could be evidenced unless the high quality educational environment was maintained. Therefore, to solve this problem, three other programs were funded as part of the overall Head Start. These three programs are the Parent-Child Center, Home Start, and the Child and Family Resources Program. The Early Training Project for disadvantaged children was implemented by Klaus and Gray of Peabody College in 1962. The program was a field research study concerned with the development and testing over time of procedures for improving the educability of young children from low income homes. Its major concern was to study whether it was possible to offset the progressive retardation observed in the public schooling careers of children, living in deprived circumstances. Children, who were trained through the Early Training Project were superior to control groups in the test of IQ and vocabulary as well as linguistic abilities, and preparation for reading. This project showed the possibilities which could prevent preschool children from being disadvantaged socially, culturally and mentally. In 1907, Montessori School was established by Maria Montessori in Italy and her school program has been introduced at present to several countries in the world as one compensatory educations. She first began her experimental methods with retarded children, followed by disadvantaged children from the tenements of Rome. The Montessori approach futures a prepared environment and carefully designed, self-correcting materials. The Montessori curriculum presents tastes that feature sequence, order, and regularity, in addition to those that develop motor and sensory skills. She was interested in children's intellectual development and in developing good work habits. One of the latest developed programs for disadvantaged children is "Integrated Preschool Program" which has successfully integrated handicapped and nonhandicapped children. Several studies have showed that handicapped children in integrated school environments are accepted by and interact with their nonhandicapped peers. In fact, this program provides a number of potential, and perhaps opportunities for nonhandicapped children to serve as valuable resources in fostering the development of their handicapped peers. Next we turn to Japanese programs which are divided into two different types. One is Day-Care Center which was established by Child Welfare Law and the other is kindergarten organized by School Education Law. The kindergarten opened in 1876 and it has been part of school systems since 1947 by the implementation of education law, and the Day-Care Center which started in 1890 for the employed mothers. was changed into Day-Nursery by the enactment of child welfare law in 1947. The laws and operational regulations for the Day-Nursery were set up and were put in effect by the establishment standard acts of children welfare facilities, and the Day-Nursery has been operated in various types by the increasing demand, chiefly because of the socio-economical changes of family structures in both urban and suburban areas. Nursery education for physically and mentally disadvantaged children is for those who are blind, deaf and dumb, mentally retarded; physically disadvantaged by accidents or diseases. Montessori education in Japan was started in 1968 and many research groups for studying Montessori were organized. In 1977, Montessori remedial education society was also organized in which they started a number of studies; a study for developing materials; in-service training for the remedial education; and seminars and lectures, etc It is strongly suggested that we study the early educations that are being implemented in Japan and a variety of compensatory educations that were already implemented in the U.S.A. and modify them for the organization of our own model and properly accommodate them to our social needs.

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Long-term Climate Change Research Facility for Trees: CO2-Enriched Open Top Chamber System (수목의 장기 기후변화 연구시설: CO2 폭로용 상부 개방형 온실)

  • Lee, Jae-Cheon;Kim, Du-Hyun;Kim, Gil-Nam;Kim, Pan-Gi;Han, Sim-Hee
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.14 no.1
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    • pp.19-27
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    • 2012
  • The open-top chamber (OTC) system is designed for long term studies on the climate change impact on the major tree species and their community in Korea. In Korea Forest Research Institute (KFRI), the modified OTC system has been operating since September 2009. The OTC facility consists of six decagon chambers (10 meters in diameter by 7 meters high) with controlled gas concentration. In each chamber, a series of vertical vent pipes are installed to disperse carbon dioxide or normal air into the center of the chamber. The OTC is equipped with remote controlled computer system in order to maintain a stable and elevated concentration of carbon dioxide in the chamber throughout the experimental period. The experiment consisted of 4 treatments: two elevated $CO_2$ levels ($1.4{\times}$ and $1.8{\times}$ ambient $CO_2$) and two controls (inside and outdoors of the OTC). Average operational rate was the lowest (94.2%) in June 2010 but increased to 98% in July 2010 and was 100% during January to December 2011. In 2010~2011, $CO_2$ concentrations inside the OTCs reached the target programmed values, and have been maintained stable in 2011. In 2011, $CO_2$ concentrations of 106%, 100% and 94% of target values has been recorded in control OTC, $1.4{\times}$ $CO_2$-enriched OTC and $1.8{\times}$ $CO_2$-enriched OTC, respectively. With all OTC chambers, the difference between outside and inside temperatures was the highest ($1.2{\sim}2.0^{\circ}C$) at 10 am to 2 pm. Temperature difference between six OTC chambers was not detected. The relative humidity inside and outside the chambers was the same, with minor variations (0~1%). The system required the highest amount of $CO_2$ for operation in June, and consumed 11.33 and 17.04 ton in June 2010 and 2011, respectively.

Adhesion Characteristics and the High Pressure Resistance of Biofilm Bacteria in Seawater Reverse Osmosis Desalination Process (역삼투 해수담수화 공정 내 바이오필름 형성 미생물의 부착 및 고압내성 특성)

  • Jung, Ji-Yeon;Lee, Jin-Wook;Kim, Sung-Youn;Kim, In-S.
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.1
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    • pp.51-57
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    • 2009
  • Biofouling in seawater reverse osmosis (SWRO) desalination process causes many problems such as flux decline, biodegradation of membrane, increased cleaning time, and increased energy consumption and operational cost. Therefore biofouling is considered as the most critical problem in system operation. To control biofouling in early stage, detection of the most problematic bacteria causing biofouling is required. In this study, six model bacteria were chosen; Bacillus sp., Flavobacterium sp., Mycobacterium sp., Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhodobacter sp. based on report in the literature and phylogenetic analysis of seawater intake and fouled RO membrane. The adhesion to RO membrane, the high pressure resistance, and the hydrophobicity of the six model bacteria were examined to find out their fouling potential. Rhodobacter sp. and Mycobacterium sp. were found to attach very well to RO membrane surface compared to others used in this study. The test of hydrophobicity revealed that the bacteria which have high hydrophobicity or similar contact angle with RO membrane ($63^{\circ}$ of contact angle) easily attached to RO membrane surface. P. aeruginosa which is highly hydrophilic ($23.07^{\circ}$ of contact angle) showed the least adhesion characteristic among six model bacteria. After applying a pressure of 800 psi to the sample, Rhodobacter sp. was found to show the highest reduction rate; with 59-73% of the cells removed from the membrane under pressure. P. fluorescens on the other hand analyzed as the most pressure resistant bacteria among six model bacteria. The difference between reduction rates using direct counting and plate counting indicates that the viability of each model bacteria was affected significantly from the high pressure. Most cells subjected to high pressure were unable to form colonies even thought they maintained their structural integrity.

College-bound Curriculum Developement for Training of Atomic Industry Technician (원자력산업 중견전문인력 양성을 위한 전문대학 교육과정 개발)

  • Lyu, Kwang-Yeul;Kim, Sung-Soo;Ahn, Sung-Min
    • Journal of radiological science and technology
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    • v.28 no.1
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    • pp.33-44
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    • 2005
  • The objective of this study is to supply the good quality of experts the radiation industries in Korea and develop the major subject matter needed in the radiation industries and the curriculum in order to execute it for the variation of fields of employment at the department of radiation in the junior college and the development of the percentage of employment. In addition, this study is to improve the level of radiation experts engaged in the industries in quality, and it is to improve the social recognition of radiation rather negative now because of the development of radiation industry. As for the core results of this research, it was to suggest the detailed choice method curriculum proper to the service fields of radiation industries, but it may be subject to change due to each college's property and the educational objectives. From the result of this research above, it may be summed up as follows. First, as for the detailed curriculum by the service field, this study was to organize two subject matters: 1. the subject matter proper to the field of using the radiation, and 2. the subject matters proper to the safety control field of radiation. Second, as for the detailed curriculum by the pattern of industries, this study was to organize the four subject matters: 1. the subject matter needed in the manufactures, 2. the subject matter needed in the nondestructive testing industries, 3. the subject matter needed in the sales agencies, and 4. the subject matter needed in the laboratories. This study was to suggest the operational model about the curriculum in order to execute these subject matters. It could be executed as two methods below. First, one method is to execute the major systems by the medical field and industrial field in the third course at the department of radiation in the junior college now. Second, the other method is to make them specialize the industrial radiation in the Advanced Course(one year course) after the graduation of junior college. To operate these curricula successively it needs to assume the deeper research and the development of materials about the subject matters related to the nuclear radiation industries hereafter. In addition, it needs to solve the security of finance like the manpower of professor, space for practice, and the educational appliances, etc. needed in the operation of subject matters. Finally, the effect and result from the development or revision of college curriculum did not come out in a short time. It will require considerable time until the undergraduates at the department in the junior college finish a set of curriculum newly developed, and graduate the university, and can get the results while they engage in their works in the industrial sites. Accordingly, all the interested parties have to anticipate the results of this research with the patience in long-standing point of view. Also, this researcher considers it as it is willing to give them the continuous interest and support.

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Analysis of the Operation Status and Function based on the Overseas Accident Investigation Agency (국외 재난원인조사기구의 운영 현황 및 기능분석)

  • Lee, Kyung-Su;Yang, Seung-Ho;Kim, Yeon-Ju;Park, Jihye;Kim, Tai-Hoon;Kim, Hyunju
    • Journal of the Society of Disaster Information
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    • v.17 no.3
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    • pp.442-453
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    • 2021
  • Purpose: The objective of this study is to suggest desirable direction of Korean accident investigation organization by analyzing the operation status and way of overseas developed countries' investigation agency. Method: To accomplish the objective of this study, we were examined four main characteristics of accident investigation agencies of the U.S., Japan, and Sweden, focusing on (1); the background of the establishment, (2);organizational structure, (3);major tasks and functions, (4); accident investigation procedures. Result: First, the purpose of its establishment and task is to prevent recurrence of disasters and accidents, at the same time, administrating and researching duties such as legal system, policy, recommending improvement and conducting scientific disaster-cause analysis to contribute safety for the government. Second, it is operated as an independent organization under the president, not belonging to the ministry, in order to enable fair investigation in an impartial position. Third, it has the authority to be recognized for its expertise in the results of investigation. In other words, it is operated as a permanent organization with professional personnel, and secures authority through the accident research with indepth investigation and high-quality recommendations. Conclusion: The overseas investigation agencies rapidly manage and coordinate their operational practices in order to resolve national requirements and social conflicts with fairness, accuracy and expertise in accident investigations. In order to prevent the recurrence of similar events, Korea needs to efficiently reconstruct its investigative functions distributed by each government department. In addition, institutional improvement is needed to make general adjustments at the national level, organize and operate control tower for when the accident has happened.