• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.93-96
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• 2015

Commercial coal gasifiers typically use entrained flow type reactors, but have unique features in terms of reactor shape, gasifying agent, coal feeding type, ash/slag discharge, and reaction stages. The MHI gasifier is characterized as air-blow dry-feed entrained reactor, which incorporates a short combustion stage at the bottom and a tall gasification stage above. This study investigates the flow and reaction characteristics inside a MHI gasifier by using computational fluid dynamics (CFD) in order to understand its design and operation features. For its pilot-scale system at 200 ton/day capacity, the distribution of coal and air supply between the two reaction stages was varied. It was found that the syngas composition and carbon conversion rate were not significantly influenced by the changes in the distribution of coal and air supply. However, the temperature, velocity and flow pattern changed sensitively to the changes in the distribution of coal and air supply. The results suggest that one key factor to determine the operational ranges of coal and air supply would be the temperature and flow pattern along the narrower wall between the two reaction stages.

• 한국동물학회지
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• 제11권3호
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• pp.99-102
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• 1968

햄스터에 대하여 水蔘을 1日 1g 씩 25日간 給與하였던 바, 다음과 같은 實驗結果를 얻었다. 1) Hb 量은 人蔘投與 10日부터 급격한 有意性 增加를 보여준다. 2) 人蔘을 給與한 뒤 15日부터 血淸總蛋白의 含量은 有意性 증가를 나타낸다. 3) 人蔘을 給與한 뒤, 10日부터 A/G率은 차차로 增加 되는 것 같이 보이지만 有意性 增加는 25日부터 나타나고 있다. 이는 globulin 보다 albumin의 含量이 더욱 增加됨을 의미한다. 요컨데 햄스터에 대하여 人蔘을 給與한 뒤, 25日간의 결과를 보명 Hb, 血淸總蛋白量 및 A/G率이 增加됨을 알게된 것이다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.246-249
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• 2004

최근 국내 건설경기의 회복세가 뚜렷해지고 건설취업자수도 증가세를 보이고 있으나 인력수급의 양적, 질적 불균형 양상이 나타나고 있고, 경제위기를 겪으면서 건설 생산 방식과 인력 활용 방식이 과도기적 양상을 나타낸다. 또한 기능인력에 대한 수요 증가와 구조적인 공급 부족 현상은 임금 상승을 가속화시켜왔으며, 생산성과 공기 조절을 비롯한 건설 생산활동 전반에 지대한 파급효과를 미치며 건설 인력 수급의 불균형 상태는 부문별로 상이한 취업구조의 변화를 야기한다. 본 연구에서는 기존에 조사된 각 연도의 건설업 임금실태 조사를 비교분석하여 건설인력수급현황을 분석하고 건설 수급 여건에 따른 건설 인력의 취업구조를 파악하여 취업구조 변화의 특성을 살펴보고 시사점을 도출한다.

• 한국CDE학회논문집
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• 제21권3호
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• pp.353-362
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• 2016

As ships become larger and construction of offshore plants increases recently, the amount of outsourcing has increased accordingly in the shipyard. Consequently, the system integration in terms of SCM (Supply Chain Management) of information and material flows has become much more important. Especially, since the SCM in the shipbuilding industry is operated in accordance with the production planning in connection with design, purchasing and production process which are the main components of the supply chain, the best production plan has to be established over the whole scheduling activities from the long-term planning to the short-term planning. The paper analyzes the characteristics of the SCM and the production planning system and suggests the need and the direction of APS (Advanced Planning System) development specialized in the supply chain management only for shipbuilding industry. Furthermore, propose a new SCP-Matrix (Supply Chain Planning Matrix), which is the basis of the APS development, appropriate for the shipbuilding industry and draw the core function of the APS module for the practical production plan.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권1호
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• pp.34-39
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• 2005

Trichloroethylene (TCE) is an environmental contaminant provoking genetic mutation and damages to liver and central nerve system even at low concentrations. A practical scheme is reported using toluene as a primary substrate to revitalize the biofilter column for an extended period of TCE degradation. The rate of trichloroethylene (TCE) degradation by Pseudomonas putida F1 at $25^{\circ}C$ decreased exponentially with time, without toluene feeding to a biofilter column ($11\;cm\;I.D.{\times}95\;cm$ height). The rate of decrease was 2.5 times faster at a TCE concentration of $970\;{\mu}g/L$ compared to a TCE concentration of $110\;{\mu}g/L$. The TCE itself was not toxic to the cells, but the metabolic intermediates of the TCE degradation were apparently responsible for the decrease in the TCE degradation rate. A short-term (2 h) supply of toluene ($2,200\;{\mu}g/L$) at an empty bed residence time (EBRT) of 6.4 min recovered the relative column activity by $43\%$ when the TCE removal efficiency at the time of toluene feeding was $58\%$. The recovery of the TCE removal efficiency increased at higher incoming toluene concentrations and longer toluene supply durations according to the Monod type of kinetic expressions. A longer duration ($1.4{\sim}2.4$ times) of toluene supply increased the recovery of the TCE removal efficiency by $20\%$ for the same toluene load.

• 조명전기설비학회논문지
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• 제14권4호
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• pp.65-72
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• 2000

본 논문은 스위칭 소자의 턴.온과 턴.오프시에 발생하는 스위칭 손실을 저감사키기 위해서 ZVS을 이용한 Push Pull형 고주파 DC-DC 컨버터를 제안하고 있다. 직류전원으로 부터 리플이 적은 정전류를 공급하기 위혜 직류리액터가 공진리액터와 접속되어 있어서 부하단락시도 안정된 동작을 할 수 있다는 잇점이 있다. 스위치 양단에 연결된 커패시터$(C_1, C_2)$는 공진요 커패시터와 ZVS용 커패시터로 동시에 사용된다. 제안한 고주파 공전 DC-DC 컨버터의 해석시 정규화 파라미터를 도입하여 범용성 있게 해석 하였으며, 설계시 기초자료가 되는 특성 평가를 하고 있다. 실제 MOSFET를 사용한 실험장치를 제작하여 설함치와 이론치를 비교.검토하여, 이론해석의 정당성을 입증하고 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.414-420
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• 2005

The ShortStack Micro Server enables any product that contains a microcontroller or microprocessor to quickly and inexpensively become a networked, Internet-accessible device. The ShortStack Micro Server provides a simple way to add LonWorks networking to new or existing smart devices. . It implements the LonTalk protocol and provides the physical interface with the LonWorks communication. The ShortStack host processor can be an 8, 16, or 32-bit microprocessor or microcontrollers. The ShortStack API and driver typically require about 4kbytes of program memory on the host processor and less than 200 bytes of RAM. The interface between host processor and the ShortStack Micro Server may be a Serial Communication Interface (SCI). The LonWorks control module with a high performance is developed, which is composed of the 8 bit PIC Microprocessor for host processor and the smart neuron chip for the ShortStack Micro Server. This intelligent control board is verified as proceeding the various function tests from experimental system with an boost pump and inverter driving systems. It is also confirmed that the developed control module provides stably 0-10VDC linear signal to the input signal of inverter driving system for varying the induction motor speed. Thus, the experimental results show that the fabricating intelligent board carried out very well the various functions in the wide operating ranges of boost pump system. This developed control module expect to apply to industrial fields to require the comparatively exact control and monitoring such as multi-motor driving system with inverter, variable air volume system and the boost pump water supply systems.

• 한국항해학회지
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• 제4권2호
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• pp.45-79
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• 1980

The aim of this paper is to analyze the mechanics of price formation in the tramp shipping. For the purpose of this study, the main characteristics of tramp freight rates and the market is examined, and a brief examination of the nature ofthe costs of operation is given which are essential for the understanding of the functioning of shipping firms as well as for the understanding of developments in the tramp freight market. The demand and supply relationships in the market is also analysed in detail. Tramp shipping is an industry that has a market which functions under conditions that are not dissimilar to the theoretical model of perfect competition. However, it does notmean that tramp shipping market is a perfectly competitive market. It is apparent that this realworld competitive system has its imperfections, which means that the market for tramp shipping is near to being a perfectly competitive market on an internaitonal scale and it is freight are therefore subjext to the laws of supply and demand. In theory, the minimum freight rate in the short term is that at which the lowest cost vessels will lay-up in preference to operating, and is equal to the variable costs minus lay-up costs; and this would imply that in all times except those of full employment for ships there is a tendency for newer low-cost, and, probably, faster vessels to be driving the older high-cost vessels in the breaker's yards. In this case, shipowners may be reluctant to lay-up their ships becasue of obligations to crews, or because they would lose credibility with shippers or financiers, or simply because of lost prestige. Mainly, however, the decision is made on strictly economic grounds. When, for example, the total operating costs minus the likely freight earnings are greater than the cost of taking the ship out of service, maintaining it, and recommissioning it, then a ship may be considered for laying-up; shipowners will, in other words, run the ships at freight earnings below operating costs by as much as the cost of laying them up. As described above, the freight rates fixed on the tramp shipping market are subject to the laws of supply and demand. In other words, the basic properties of supply and demand are of significance so far as price or rate fluctuations in the tramp freight market are concerned. In connection with the same of the demand for tramp shipping services, the following points should be brone in mind: (a) That the magnitude of demand for sea transport of dry cargoes in general and for tramp shipping services in particular is increasing in the long run. (b) That owning to external factors, the demand for tramp shipping services is capable of varying sharphy at a given going of time. (c) The demad for the industry's services tends to be price inelastic in the short run. On the other hand the demand for the services offered by the individual shipping firm tends as a rule to be infinitely price elastic. In the meantime, the properties of the supply of the tramp shipping facilities are that it cannot expand or contract in the short run. Also, that in the long run there is a time-lag between entrepreneurs' decision to expand their fleets and the actual time of delivery of the new vessels. Thus, supply is inelastic and not capable of responding to demand and price changes at a given period of time. In conclusion, it can be safely stated that short-run changes in freight rates are a direct result of variations in the magnitude of demand for tramp shipping facilities, whilest the average level of freight rates is brought down to relatively low levels over prolonged periods of time.

• The Journal of Asian Finance, Economics and Business
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• 제5권3호
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• pp.7-17
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• 2018

This paper examines short-run and long-run dynamic relationships between selected macroeconomic variables and stock prices in the Korea Stock Exchange. The data is restricted to the period for which monthly data are available from January 1986 to October 2016 (370 observations) retrieved from the Economic Statistics System database sponsored by the Bank of Korea. The study employs unit root test, cointegration test, vector error correction estimates, impulse response test, and structural break test. The results of the Johansen cointegration test indicate at least three cointegrating equations exist at the 0.05 level in the model, confirming that there is a long-run equilibrium relationship between stock prices and macroeconomic variables in Korea. The results of vector error correction model (VECM) estimates indicate that money supply and short-term interest rate are not related to stock prices in the short-run. However, exchange rate is positively related to stock prices while the industrial production index and inflation are negatively related to stock prices in the short-run. Furthermore, the VECM estimates indicate that the external shock, such as regional and global financial crisis shocks, neither affects changes in the endogenous variables nor causes instability in the cointegrating vector. This study finds that the endogenous variables are determined by their own dynamics in the model.

• 한국농촌건축학회논문집
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• 제14권1호
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• pp.1-8
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• 2012

This study was to analyze physical condition on the dormitory high school in Jeonju City, and find out users' satisfaction on that. This was going to contribute to the directions of it's physical environmental improvement. This was performed by a questionnaire survey method. Data were collected from 200 students, who had been dwelling 4 high school dormitories in Jeonju City. Through analyzing those data about library, diningroom, laundry room, break room, computer room, restroom, shower room, hall lounge, and snack bar in a dormitory, the results are as follows. First, students thought some physical conditions to be inconvenient in an distracted study atmosphere and hard furniture of library, a bad location of diningroom, a short laundry machine, lack of tables in a break room, a short performance and supply computer, a small space and short toilet in restroom, and a short of hall lounge and snack bar. Second, the students' satisfaction of common public areas in dormitory was 3.39 score. Students were concerned with library and restroom shower room through analyzing satisfied and unsatisfied areas. Third, they needed to improve heating, cooling, and noise in common areas of dormitory, and needed to support a breakroom and snack bar. Conclusively, library, restroom shower room, break room, and snack bar were important common areas, and indoor environmental elements - heating, cooling and noise- were important in high school dormitory.