• Title/Summary/Keyword: on-off control

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A Study on the Safety Management Methods of Micro-Gas Engine Combined Heat and Power System (소형 가스엔진 열병합발전 시스템의 안전관리 방안에 관한 연구)

  • Kim, So-Hyun;Kim, Min-Woo;Lee, Eun-Kyung;Lee, Jung-Woon
    • Journal of the Korean Institute of Gas
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    • v.22 no.6
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    • pp.76-89
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    • 2018
  • The distribution of the combined heat and power system is active as a solution to the instability of energy supply and environmental pollution caused by continuous industrial development. In Korea, the safety standards for combined heat and power system using a gas engine are insufficient therefore the study on this is needed. In this study, the safety performance and structural/material assessment items of domestic and international standards applied to the combined heat and power system were analyzed to carry out a standardization study on safety performance applicable to 20 kW gas engine combined heat and power system. In addition, the safety performance assessment (plan) of the gas engine combined heat and power system was derived by performing risk analysis and risk assessment using HAZOP. Assessment items include engine ignition systems related to safety performance, piping tight performance, watering and temperature rise performance, combustion performance, electrical efficiency, thermal efficiency, overall efficiency and humidity performance. Gas and water pipes, gas control and shut-off valves, durability, heat resistance, and cold resistance of metal or non-metallic materials related to the structure and materials of the gas engine combined heat and power systems.

A Study on the Acquisiton Methods of Theater Collections (연극기록물의 수집방안 연구)

  • Jung, Eun Jin
    • The Korean Journal of Archival Studies
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    • no.29
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    • pp.35-78
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    • 2011
  • This study is intended to recommend for acquisition methods of the theatre collection. Theatre activities is representative of the performing arts, and the Korea theatre history start from the modern history of Korea. In the meantime, theatre collections has already been lost by a lack of effort and management, and scattered most of the collections. In particular, a one-off nature and volatility of theatrical performances make future generations to enjoy the performances and to study should consult the relevant records. Therefore, collecting records can be very serious mission. In this study, theatre collections of the country which aims to collect and analyze the characteristics and type of theatre collections. Based on this information, collection scope, targets, priorities, acquisition level, method of collecting are proposed the following. First, collection scope is defined for the theatre related collections which was performed nationwide in the 1900s, the times that modern theatre was begun. The object includes related information of planning, administration, drama (script), directing, stage design, public relations, production, evaluation, personal records, biographical data, group data and space data. Second, the theatre collections are divided into records and historical records. Priority of collections object is determined by the historical value and the theatre performed by the support of public organization. Third, the acquisition level is divided into archived, mirrored, web linked and database, which is proposed by the determined levels of mandatory, recommend and discretion according to the characteristic of performance. Fourth, acquisition methods are suggested by the general acquisition methods of transfer, donation and purchase as well as the methods of copy, production, legal deposit, entry and web link etc. The acquisition of theatre collections is executed on digital-based environment, and a centralized authority control should be establishmented. And through the development of network with theatre's stakeholders and the cooperation of related organizations, theatre collections acquisition is feasible.

The politics of shadow education market expansion in Korea: Focused on mobilization capabilities and strategies of suppliers (한국 사교육 정책의 작동 메커니즘에 대한 정치적 분석: 공급자의 동원능력과 시장전략을 중심으로)

  • Hwang, Gyu-Seong
    • 한국사회정책
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    • v.20 no.2
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    • pp.233-260
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    • 2013
  • Despite various policies have been implemented to curb shadow education in Korea, it has continued to grow in recent two decades. This study investigates the expansion mechanism of shadow education focused on mobilization capabilities and market strategies of the suppliers. The success and failure of policy toward shadow education depends on how effectively it could block off the way by which the suppliers as the most important actors in politics of shadow education market mobilize consumers' anxieties. But shadow education policies have failed in two points. First, they have lacked honest intention to stop its proliferation. The Constitutional Court Decision Against Anti-Out-Of-School Classes Legislation of 2000 widened the windows of opportunity for the suppliers, and 5.31 educational reform of 1995 was neutral to their mobilization capabilities, though seemingly designed to control shadow education. This policy orientation, which reflected neoliberal Gesinnungsethik defective of Verantwortungsethik, stimulated shadow education to expand in that suppliers' mobilization capabilities were reinforced or remained intact. Second, shadow education suppliers have succeeded in mobilizing the desire and anxiety of potential consumers. To cope with government's policy including improving the qualities of public education, realignment of college entrance systems, and meeting the shadow education needs, they have developed various market strategies such as management of existing demands, creation of responsive demands, and squeezing out new demands. They have succeeded in nullifying policies by employing or mixing strategies with effect. Policy decisions in the future need to be made with reference to Verantwortungsethik, and be more cautious to socio-political contexts of Korea, to mobilization capabilities and market strategies of the suppliers in particular.

Exploring the Transnational Mobility and Work Experience of Young Koreans in Singapore (초국적 이동성과 일 경험: 한국 청년들의 싱가포르 해외취업 사례 연구)

  • YUK, Joowon
    • The Southeast Asian review
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    • v.28 no.3
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    • pp.111-158
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    • 2018
  • This paper pays attention to the recent increase of young Koreans working in the low-skilled service sector in Singapore. Such rapid increase largely results from the Korean government's initiatives to promote labour migration of young people and the concurrent proliferation of migration agencies, against the background of growing youth unemployment in South Korea. By exploring the motivations and trajectories of young people's labour migration to Singapore, this study examines to what extent they think their expectations have been met and how they interpret their migration and work experiences. There has been little research that examines the actual voices of young migrants as part of migration studies, whilst the majority of previous research focuses on the evaluation of government support programmes based on job matching rates, surveys of participant satisfaction and etc. Young people who went to Singapore to improve their English language skills and qualifications for future employment in Korea have become frustrated due to low-skilled service jobs that consist of low pay and high labour intensity. Their credentials are devalued and they experience deskilling through this migration process. Most of them were discontent with the Korean migration agencies they used and critical about programmes offered by government institutions and universities/colleges. Despite being subject to deskilling, they did try to actively cope or resist this situation. This study focuses on the various ways these migrants attempted to manage the gap between their initial expectations and reality. It also demonstrates how these migrants interpreted their work experiences after returning to Korea: whilst most of them did not cash off their Singapore work experience for a decent job after returning to Korea, they did not define their experience as a complete failure. Adding to cultural, social capital they gained through this experience, they acquired 'mobility capital' which includes confidence, the desire to move, and capacity to control one's own movement.

Rice Seedling Establishment for Machine Transplanting VI. Effect of Mulching Materials on Raising Rice Seedling at Tray for Machine Transplanting (수도 기계이앙 육묘에 관한 연구 Ⅵ.제6보 상자육묘시 피복자재이용 효과)

  • Yun, Yong-Dae;Yang, Won-Ha;Kwang, Yong-Ho;Park, Seok-Hong;Park, Rae-Kyeong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.31 no.1
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    • pp.9-15
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    • 1986
  • To establish an efficient light control method using three covering materials on tunnel shaped rice seed-bed at greening stage after seedling emergence, four rice cultivars, Nampungbyeo, Taebaegbyeo, Seonambyeo, and Seomjinbyeo were sown on 15 April and 10 May in 1983 and 1984 respectively. After seedling emergence by a simplified emerging methods the seedling boxes were moved onto tunnel shaped seed-bed which was covered with combined matrials of PE film, silverpoly sheet, and spunbonded polyester fabric. For machine transplanting of rice seedlings in cases of early season and optimum season seeding in central part of Korea, PE film tunnel with silverpoly mulched, and PE film tunnel methods with spunbonded polyester fabric mulched reduced injuries of non-parasitic seedling damping-off and a albinism as affected by it, protected rice seedlings from injuries by extremely low temperature in the night, and reduced less differences in diurnal temperature than those in the other covering methods. At late season seeding for double cropping system of paddy field in southern part of Korea, a single silver-poly or a single spunbonded polyester fabric-covered tunnel method showed good green seedlings, and prevent-ed extreme rising of diurnal temperature by light interception in the tunnel.

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Suppressive Mechanism of Soil-borne Disease Development and its Practical Application -Isolation and Identification of Species of Trichoderma Antagonistic to Soil diseases and its activities in the Rhizosphere- (토양병의 발병억제 기작과 그 실용성 -길항성 Trichoderma spp.의 분리, 동정 및 근권내 활동-)

  • Kim, S.I.;Shim, J.O.;Shin, H.S.;Choi, H.J.;Lee, M.W.
    • The Korean Journal of Mycology
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    • v.20 no.4
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    • pp.337-346
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    • 1992
  • Trichoderma spp. are an effective control agent for damping-off or other plant diseases. The interaction between. T. hamatum and Rhizoctonia solani on the rhizosphere or surface soil were examined to assess the possible roles of antibiosis or competition in the mechanisms of biological control agents as a basic research. In a proportional comparison, total bacteria, fungi, actinomycetes and Trichoderma spp were 65%, 8.8%, 25.9% and 0.28% respectively in their distribution in the soil. Among Trichoderma spp isolated, the 5 species of Trichoderma spp were indentified as T. koninggii, T. pseudokoninggii, T. aureoviridi, T. hamatum and T. viride respectively. In a mycoparasitic test, one isolate of T. hamatum strain Tr-5 showed an enzymatic ability to break fungal hyphae into piecies and infected on the R. solani hyphae showing a parasitism. Spore germination of the all isolates of Trichoderma spp showed a 1.7-7.3% of germination in natural soil conditions, but the percentage was high in sterile soil indicating all the natural soil were fungistatic on conidia of Trichoderma spp. In rhizosphere competent assay in pea plant, the antagonistic T. hamatum, T. viride, T. koninggii, T. pseudokoninggii showed a colonizing upper soil depth in rhizosphere around 1-3 cm in root zone, but the colonizing ability was much reduced along the deeper the soil depth. Propagule density was decreased in deeper the soil layer. Disease development rate treated alone with plant pathogens, Fusarium solani, Rhizoctonia solani, Cylindrocarpon destructans increased, but disease incidence rate reduced in treatment with combinations with antagonistic T. hamatum strain Tr-5.

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Development and Application of the High Speed Weigh-in-motion for Overweight Enforcement (고속축하중측정시스템 개발과 과적단속시스템 적용방안 연구)

  • Kwon, Soon-Min;Suh, Young-Chan
    • International Journal of Highway Engineering
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    • v.11 no.4
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    • pp.69-78
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    • 2009
  • Korea has achieved significant economic growth with building the Gyeongbu Expressway. As the number of new road construction projects has decreased, it becomes more important to maintain optimal status of the current road networks. One of the best ways to accomplish it is weight enforcement as active control measure of traffic load. This study is to develop High-speed Weigh-in-motion System in order to enhance efficiency of weight enforcement, and to analyze patterns of overloaded trucks on highways through the system. Furthermore, it is to review possibilities of developing overweight control system with application of the HS-WIM system. The HS-WIM system developed by this study consists of two sets of an axle load sensor, a loop sensor and a wandering sensor on each lane. A wandering sensor detects whether a travelling vehicle is off the lane or not with the function of checking the location of tire imprint. The sensor of the WIM system has better function of classifying types of vehicles than other existing systems by detecting wheel distance and tire type such as single or dual tire. As a result, its measurement errors regarding 12 types of vehicle classification are very low, which is an advantage of the sensor. The verification tests of the system under all conditions showed that the mean measurement errors of axle weight and gross axle weight were within 15 percent and 7 percent respectively. According to the WIM rate standard of the COST-323, the WIM system of this study is ranked at B(10). It means the system is appropriate for the purpose of design, maintenance and valuation of road infrastructure. The WIM system in testing a 5-axle cargo truck, the most frequently overloaded vehicle among 12 types of vehicles, is ranked at A(5) which means the system is available to control overloaded vehicles. In this case, the measurement errors of axle load and gross axle load were within 8 percent and 5 percent respectively. Weight analysis of all types of vehicles on highways showed that the most frequently overloaded vehicles were type 5, 6, 7 and 12 among 12 vehicle types. As a result, it is necessary to use more effective overweight enforcement system for vehicles which are seriously overloaded due to their lift axles. Traffic volume data depending upon vehicle types is basic information for road design and construction, maintenance, analysis of traffic flow, road policies as well as research.

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An Experimental Study on Real Time CO Concentration Measurement of Combustion Gas in LPG/Air Flame Using TDLAS (TDLAS를 이용한 LPG/공기 화염 연소가스의 실시간 CO 농도 측정에 관한 연구)

  • So, Sunghyun;Park, Daegeun;Park, Jiyeon;Song, Aran;Jeong, Nakwon;Yoo, Miyeon;Hwang, Jungho;Lee, Changyeop
    • Clean Technology
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    • v.25 no.4
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    • pp.316-323
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    • 2019
  • In order to enhance combustion efficiency and reduce atmosphere pollutants, it is essential to measure carbon monoxide (CO) concentration precisely in combustion exhaust. CO is the important gas species regarding pollutant emission and incomplete combustion because it can trade off with NOx and increase rapidly when incomplete combustion occurs. In the case of a steel annealing system, CO is generated intentionally to maintain the deoxidation atmosphere. However, it is difficult to measure the CO concentration in a combustion environment in real-time, because of unsteady combustion reactions and harsh environment. Tunable Diode Laser Absorption Spectroscopy (TDLAS), which is an optical measurement method, is highly attractive for measuring the concentration of certain gas species, temperature, velocity, and pressure in a combustion environment. TDLAS has several advantages such as sensitive, non-invasive, and fast response, and in-situ measurement capability. In this study, a combustion system is designed to control the equivalence ratio. Also, the combustion exhaust gases are produced in a Liquefied Petroleum Gas (LPG)/air flame. Measurement of CO concentration according to the change of equivalence ratio is confirmed through TDLAS method and compared with the simulation based on Voigt function. In order to measure the CO concentration without interference from other combustion products, a near-infrared laser at 4300.6 cm-1 was selected.

Quality and Shelf-Life of Vacuum Packed RTE (Ready-To-Eat) Hamburg Steak Depending on the Oxygen Permeability of Packaging Material and the Storage Temperature (포장재의 산소투과도와 저장온도에 따른 즉석섭취형 햄버그스테이크의 품질 및 저장성)

  • Lim, Ji Hoon;Lee, Sung Ki;Chung, Seung Hee;Lee, Keun Taik
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.22 no.3
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    • pp.95-102
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    • 2016
  • This study investigated the effects of the oxygen permeability of vacuum packaging film and the storage temperature on the quality and shelf life of Hamburg steaks during storage for 14 days. Control samples (C) were packaged in a polyamide/polyethylene (PA/PE) film and stored at $5^{\circ}C$. Treatment samples were either packaged in an ethylene vinyl alcohol/polyethylene (EVOH/PE) copolymer film and stored at $5^{\circ}C$ (T1), and in a PA/PE film and stored at $-18^{\circ}C$ (T2). The initial total plate count (TPC) was 3.6 log cfu/g. In T1 samples, TPC and Brochothrix thermosphacta counts were increased, similar to those in C samples, whereas Pseudomonas spp. counts were significantly lower than those in C samples during storage. Over the storage period, the volatile basic nitrogen values increased most rapidly in C samples, followed by T1 and then T2 samples. The values of thiobarbituric acid reactive substances steadily increased in all samples during storage. The colour parameters were not significantly different among the samples during storage. T1 samples maintained sensory qualities in flavour and off-odour parameters for two days longer than C samples did. At day 12, T2 samples were evaluated as being below the marketability score of 5.0 for texture. In conclusion, using high oxygen barrier films like EVOH/PE copolymer for packaging Hamburg steaks could extend the sensory qualities in view of flavour and off-odour during chilled storage. However, frozen storage at $-18^{\circ}C$ is recommended when the storage period is extended beyond 14 days at $5^{\circ}C$.

Diagnostic Value of Serum CYFRA 21-1 in Lung Cancer (폐암에서 혈중 CYFRA 21-1의 진단적 가치)

  • Yoon, Hyun-Dae;Kim, Ki-Deok;Chung, Jin-Hong;Lee, Hyung-Woo;Lee, Kwan-Ho;Lee, Hyun-Woo;Cho, Ihn-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.2
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    • pp.149-155
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    • 1995
  • Background: Cytokeratin 19 is 40KD acidic molecule whose distribution is restricted to simple or pseudo-stratified epithelia, such as the epithelial layer of the bronchial tree. Immunohistochemical study have shown that cytokeratin 19 is overexpressed in lung carcinoma tissue. An immunoradiometric assay, CYFRA 21-1 has been developed using two monoclonal antibody, BM 19-21 and KS 19-1, reactive to different epitopes on cytokeratin 19. We studied the diagnostic value of CYFRA 21-1 in lung cancer. Method: The serum CYFRA 21-1 level using immunoradiometric kit(ELSA-CYFRA 21-1) was measured in 54 patients who admit to Yeungnam University Hospital from April, 1993 to August, 1994. Lung cancer group was 39 primary lung cancer patients(19 patients with squamous cell carcinoma, 11 patients with adenocarcinoma and 9 patients with small cell carcinoma). Control group was 15 patients with non malignant lung diseases(8 patients with pulmonary tuberculosis, 3 patients with chronic obstructive pulmonary disease, 2 patients with pneumonia and 2 patients with chronic obstructive pulmonary disease combined with pulmonary tuberculosis). Results: The mean serum value of CYFRA 21-1 was $20.2{\pm}4.7ng/ml$ in squamous cell carcinoma, $7.2{\pm}1.6ng/ml$ in adenocarcinoma and $15.5{\pm}4.7ng/ml$ in non-small cell lung cancer. The serum value of CYFRA 21-1 in control group was $1.7{\pm}0.5ng/ml$. All of the serum values of 3 histologic types were significantly higher than that of control group(p<0.01). The serum value of CYFRA 21-1 of squamous cell carcinoma was significantly higher than that of adenocarcinoma(p <0.05). Serum value of CYFRA 21-1 in small cell lung cancer was $2.9{\pm}0.9ng/ml$ and not significantly different compared with control group. Using cut off value of 3.3ng/ml, sensitivity and specificity was 11.1%, 65.2% in small cell lung cancer, 70.0%, 62.5% in non-small cell lung cancer, 73.7%, 75% in squamous cell carcinoma and 63.6%, 78.9% in adenocarcinoma, respectively. Conclusion: The serum levels of CYFRA 21-1 may be useful in diagnosis of non-small cell lung carcinoma, especially in squamous cell carcinoma with its high specificity.

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