• Clean Technology
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• v.23 no.2
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• pp.181-187
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• 2017

The perfluorocompounds (PFCs) emitted from the semiconductor and display manufacture is treated by abatement systems which use various technologies, such as combustion, thermal, plasma, catalyst. However, it is required that the system should overcome their drawbacks with excess energy consumption and low removal efficiency. The new technology using combination of pressure swing adsorption and excess enthalpy combustion for the reduction of PFCs emissions were developed and analyzed its characteristics. PFCs concentration ratio and PFCs loss factor were calculated from measuring concentration of PFCs at the calculated by comparing concentration of PFCs at the combustor's inlet and outlet. There were performance evaluations with various gas flow for comparing energy consumption and removal efficiency with existing equipments. The concentration ratio and the loss factor of PFCs were 1.65, 8.2%, respectively, when the total gas flow of the pressure swing absorption (PSA) inlet was 204 liter per minute (LPM) and $CF_4$ concentration was 1412 ppm. In comparison with existing system at constant condition, $CF_4$ removal efficiency for a porous media combustion (PMC) showed the improvement more than 16% and the consumed energy was also reduced up to approximately 41%. Then, the total gas flow introduced into PMC and $CF_4$ concentration were 91-LPM and 2335 ppm, respectively, and the destruction and removal efficiency of $CF_4$ was about 96% at 19-LPM $CH_4$, and 40-LPM $O_2$.

• Korean Journal of Psychosomatic Medicine
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• v.5 no.1
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• pp.52-62
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• 1997

This study was designed to determine the frequency of premenstrual dysphoric disorder in gynecological outpatients, and also attempted to compare premenstrual change characteristics, functional impairment due to premenstrual changes and frequency of risk factors reported by women with confirmed premenstrual changes$(PMC^+)$(n=17) and those without confirmed premenstrual changes$(PMC^-)$(n=23). Forty gynecological outpatients who complained of premenstrual discomforts were asked to complete questionnaires on menstrual history, obstetric-gynecological history, and premenstrual change and functional impairment. The women were also asked to complete a daily rating form based on DSM-IV diagnostic criteria for one menstrual cycle. Absolute severity method, effect size method and percent change method were used to assess changes between follicular phase and luteal phase. The results of the study were as follows: 1) The frequency of premenstrual dysphoric disorder according to each of the three methods was 5% for the absolute severity method, 15% for the effect size method, and 27.5% for the percent change method. 2) The frequently reported symptoms were as follow: physical symptoms(64.7%) : lethargy, easy fatigability, or marked lack of energy(41.2%) : decreased interest in usual activities(29.4%) ; and marked affective lability(23.5%). 3) There were no significant differences in onset ages of premenstrual changes, regularities of premenstrual changes and changes of severity and duration of premenstrual symptoms over time between women with and without confirmed premenstrual changes. However, women with confirmed premenstrual changes reported both physical and emotional symptoms as earliest symptoms most frequently, while women without confirmed premenstrual changes reported only physical symptoms most frequently. 4) functional impairment was significantly higher in women with confirmed premenstrual changes than those without confirmed premenstrual changes, but impairment was not severe. 5) No differences were found between women with and without confirmed premenstrual changes in risk factors including demographic data, menstrual and obstetric and gynecological history. These results suggest that the prevalence of premenstrual dysphoric disorder varies with scoring methods. The women with confirmed premenstrual changes reported physical symptoms most frequently(64.7%). functional impairment was significantly higher in women with confirmed premenstrual changes, but impairment was not severe.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.163-173
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• 2010

A significant number of projects have been managed by US Army Corps of Engineers FED. Today, more information must be provided to the parties involved in the projects by phase than ever before. Specifically, USFK`s construction projects have been managed by FED(Far East District). Recently, however, large US private construction companies have been filling the role previously taken by FED. However, there is few construction managers to implement FED project in Korea. Accordingly, this study analyzes FED projects practices with focus on the construction management actors in order to suggest guideline. This study suggests a model FED construction process(Bid, Contract, Construction, As-Built Phase) by analyzing the existing FED project process using a IDEF0 methodology.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.38-44
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• 2002

The effect of lime on plant availability of heavy metals in soils amended with industrial sewage sludge (ISS) or pig manure compost (PMC) was investigated. A pot experiment with Altari radish (Raphanus sativus) was conducted. Industrial sewage sludge and Pig manure compost were added at 25 and 50 Mg/ha, and lime was added at 3 Mg/ha. Heavy metal contents of ISS treated soils after experiment were higher than those in control (NPK plot) and PMC treatment. Specially, the contents of copper, zinc, nickel and chromium in the 50 Mg/ha of ISS treated soils were higher 12$\sim$48 times than those in control. Copper, zinc, and nickel contents in Altari radish leaves cultivated at the ISS treated soil exceeded the critical levels of plant toxicity. Copper, zinc, and nickel contents in Altari radish loaves and roots cultivated at the ISS treated soil were reduced by the addition of lime. Copper, zinc, and nickel contents in Altari radish loaves were negatively correlated with soil pH after experiment. It concluded that liming would reduce the uptake of heavy metals by plants and be a temporary method of reclamation at the highly heavy metal accumulated soils by ISS.

• Journal of Korean Library and Information Science Society
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• v.52 no.2
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• pp.25-44
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• 2021

In a situation where OA papers are increasing, POI, which indexes how open the research activities of individual researchers are, is drawing attention. This study investigated the existence of OA papers and the OA method published in international academic journals by domestic LIS researchers, and derived the researchers' POI based on this. In addition, by examining the relationship between the POI index and the researcher's amount of research papers, the research sub field, and the foreign co-authors, it was analyzed whether these factors are relevant to the researcher's POI. As a result, there were 492 papers by 82 researchers whose OA status and method were normally identified through Unpaywall. Second, only 20.7% of papers published in international journals were open accessed, and almost cases were gold and green methods. Third, there were many papers in text mining in medical journals, and the papers opened in the green method are open in institutional repositories of foreign co-authors or transnational subject repositories such as PMC. Third, the POI index was relatively higher for researchers in the field of informetrics, machine learning than other fields. In addition, it was analyzed that the presence or absence of overseas co-authors is related to OA.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.18-18
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• 1996

This paper reviews some of the most prominent and promising areas of chemical process control both in relations to batch and continuous processes. These areas include the modeling, optimization, control and monitoring of chemical processes and entire plants. Most of these areas explicitly utilize a model of the process. For this purpose the types of models used are examined in some detail. These types of models are categorized in knowledge-driven and datadriven classes. In the areas of modeling and optimization, attention is paid to batch reactors using the Tendency Modeling approach. These Tendency models consist of data- and knowledge-driven components and are often called Gray or Hybrid models. In the case of continuous processes, emphasis is placed in the closed-loop identification of a state space model and their use in Model Predictive Control nonlinear processes, such as the Fluidized Catalytic Cracking process. The effective monitoring of multivariate process is examined through the use of statistical charts obtained by the use of Principal Component Analysis (PMC). Static and dynamic charts account for the cross and auto-correlation of the substantial number of variables measured on-line. Centralized and de-centralized chart also aim in isolating the source of process disturbances so that they can be eliminated. Even though significant progress has been made during the last decade, the challenges for the next ten years are substantial. Present progress is strongly influenced by the economical benefits industry is deriving from the use of these advanced techniques. Future progress will be further catalyzed from the harmonious collaboration of University and Industrial researchers.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.284-287
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• 2004

본 논문의 목표는 일체형 디지털 TV에서 디지털 방송 수신과 방송 컨텐츠를 녹화, 저장, 재생이 가능할 뿐만 아니라 조만간 시작될 데이터 방송을 수신할 수 있는 내장형 디지털 방송수신 및 개인 비디오 저장 시스템 Platform 개발이다. 디지털 방송과 데이터방송 수신이 가능한 Set-Top Box 기능, 수신된 방송의 저장 및 재생이 가능한 PVR 기능을 지원할 수 있는 시스템의 구조를 설계하였다. 고품질 디지털 방송 서비스가 본격적으로 시작됨에 따라 디지털 방송 수신기와 PVR 기능이 복합된 제품의 수요가 증가할 것으로 예상되며 이러한 고성능 복합시스템은 필수적일 것이다. 이러한 기능을 수행하기 위하여 시스템 제어를 위한 CPU로는 PMC-Sierra 사의 MIPS Architecture에 기반을 둔 RM5231을 채택하고, Teralogic 사의 TL811 System Controller을 채택하여 시스템을 이루고 있는 각종 디바이스를 구성하고, MPEG-2 Demux/Decoding을 위해 Teralogic TL851 Graphics & Display Processor을 채택하였다. 개발된 시스템을 테스트하기 위하여 현재 각 방송사들의 시험 방송을 수신하고 PVR 기능을 테스트하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.9
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• pp.78-84
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• 2020

This paper introduces the structural and vibration analysis performed in the localization development process of hydraulic pumps used in wheeled armored vehicles. The maximum strain, maximum stress, maximum displacement, and minimum safety factor were calculated using structural analysis. Furthermore, it was found that the dangerous resonance frequency was avoided through vibration analysis. In addition, the reliability of the analysis results was verified by passing various tests, such as the actual vibration test and the actual durability test. The developed hydraulic pump is expected to contribute significantly to the maintenance of military vehicles in the future.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.05a
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• pp.115-116
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• 2010

방사성농축폐액처리를 위한 Polymer-Modified-portlandcement 고화체는 Polymer 및 시멘트, 물을 혼합매질로 제조되며 농축폐액처리를 위해 Emulsion Polymer를 사용하였으며 PMC 고화체의 물성을 평가하기위한 고화체의 제조에서 이들 매질의 최적혼합비를 찾기 위해 Polymer 및 물, 시멘트의 혼합비를 1/1/2,1/2/4,1/3/9 등 혼합비에 따른 시편 및 Polymer 첨가량의 증가에 따라 함유비를 달리하는 시편을 제조하여 경화시간별 압축강도를 측정하였으며 매질의 최적혼합비 및 폴리머의 투입비를 구하고자하였다. 특성평가시험을 위한 시편으로는 직경 50, 높이 100mm(L/D=2) 인시편을 제조하여 압축강도를 측정하였으며 폴리머와 시멘트의 결합상태를 확인하기위해 SEM사진을 통한 미세구조를 관찰하였으며 시험결과 P/W/C의비가 1/3/9인 혼합비시편의 압축강도가 $343.36Kg_f/cm^2$로 가장 높았으며 폴리머의 함유량을 달리한 시험에서는 7%폴리머 함유시편은 $397.24Kg_f/cm^2$, 20% 폴리머함유시편은 $175.36Kg_f/cm^2$으로 폴리머의 함유량이 7~15% 이내의 폴리머함유고화체가 적합한 것으로 판단되었으며 폴리머의 투입양이 증가할수록 압축강도가 감소하였으며 경화시간도 최소4주이상 되어야하는 것으로 판단되었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1173-1182
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• 2001

Recent noticeable advances of CNC machine tools have considerably improved productivity and precision in manufacturing processes. However, in the respect of productivity some defects still remain because selection of machining conditions entirely depends on the experiences of programmers. Usually, machining conditions such as feed rate and spindle speed have been selected conservatively by considering the worst cases, and it has brought the loss of machining efficiency. Thus, the improvement of cutting force controller has been done to regulate cutting force constantly and to maximize feedrate simultaneously in case that machining conditions change variously. In this study, sliding mode control with boundary layer is applied to milling process for cutting force regulation and in a commercial CNC machining center data transfer between PC and PMC (programmable machine controller) of CNC machine is done using a standard interface method. And in the cutting force measurement, an indirect cutting force measuring system using current signal of AC servo is adopted in order not to use high-priced equipment like tool dynamometer. The purpose of this study is to maximize the productivity in milling process, thus its results can be applied to cases such as rough cutting process.