• 한국통신학회논문지
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• 제14권4호
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• pp.423-434
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• 1989

본 논문에서는 디지털 변환다중장치의 각 채널의 PRS 전송 방식을 적용하였을 때 나타나는 문제점들을 도출하고, 이들을 해결학기 위하여 단위펄스로 TMRCP를 사용한 PRS 전송 시스쳄을 제안하였으며, 이를 FFT 다위상 여파기를 이용한 변환다중장치의 개념에 적용하여 설계하는 기법을 제시 하였다. 4KHz로 대역 제한된 음성채널에 대하여 약 2.5KHz(Guard-band 포함)의 대역폭을 요구하는 TMRCP-PRS 신호를 24채널의 체계에 적용하므로서 전송로 상에서 나타나는 PRS 방식의 잇점을 그대로 유지하며, 채널간의 간섭 문제를 해결하고, 속도 융통성을 향상시키므로 체계의 호나경에 따르는 시간 오류는 물론 손실 전력을 감소 시킬 수 있는 안정된 시스템을 구성한다. 전체 시스템은 일반적인 변환다중장치의 전후에 TMRCP를 이용한 PCM-PRS, PRS-PCM 변환기를 첨가한 형태로 이루어진다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 추계학술발표대회
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• pp.20-23
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• 2020

This research is to design an effective prefetching method required for DRAM-PCM hybrid main memory systems especially used for big data applications and massive-scale computing environment. Conventional prefetchers perform well with regular memory access patterns. However, workloads such as graph processing show extremely irregular memory access characteristics and thus could not be prefetched accurately. Therefore, this research proposes an efficient dynamical prefetching algorithm based on the regression method. We have designed an intelligent prefetch engine that can identify the characteristics of the memory access sequences. It can perform regular, linear regression or polynomial regression predictive analysis based on the memory access sequences' characteristics, and dynamically determine the number of pages required for prefetching. Besides, we also present a DRAM-PCM hybrid memory structure, which can reduce the energy cost and solve the conventional DRAM memory system's thermal problem. Experiment result shows that the performance has increased by 40%, compared with the conventional DRAM memory structure.

• 폴리머
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• 제34권3호
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• pp.261-268
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• 2010

본 연구에서는 상전이 온도가 36 $^{\circ}C$인 n-eicosnae을 열가소성 폴리올레핀 고분자인 폴리프로필렌과 블렌드하였으며, 또한 최근의 형태안정성 PCM(SSPCM)의 연구검토를 통하여 폴리프로필렌과 n-eicosnae의 특성과 잠열저장체로서의 적용 가능성을 확인하였다. 상전이 온도가 36 $^{\circ}C$인 n-eicosane과 폴리프로필렌을 멜팅방법과 흡수방법을 이용하여 시료를 제조하였다. 제조된 형태안정성 PCM(SSPCM)을 DSC, WAXD, FTIR spectroscopy, ARES로 분석결과 형태안정성, 열용량의 향상을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.63-66
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• 2008

Not only mechanical properties, bonding properties, electro chemical properties, etc. but also fire safety is required in patch repair materials such as polymer modified cement mortar (PCM) which are used to deteriorated reinforced concrete structure. Unfortunately, it is very difficult to choice the appropriate repair materials because there are not enough information about fire safety properties of PCM. In this study, The combustion characters of PCM were evaluated through the heat release rate test and non-combustibility test. The pyrogenicity test uses the cone calorimeter based on the oxygen consumption method. The non-combustibility test is from the temperature change inside the furnace during the test. The effect of the types of polymer and polymer content were evaluated from the series of test. The results are like followings. 1) The higher the W/C of PCM, the lower the gross calorific value and heat generation rate in the heat release rate test. The amount of heat generation of PCM is like the order of VVA, EVA, and SBR in this study. 2) Some materials such as E45-100, E50-100, E60-100, S50-50, and S50-100 were estimated as not appropriate building materials in the non combustibility test.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.517-522
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• 2005

A cold storage refrigerator using phase change material(PCM) has been developed and its performance test results are provided here. The inner temperature of the refrigerator is controlled with forced convection driven by a fan using a DC battery. At the first, to freeze all the PCM of the ambient temperature by a built-in refrigerating machine, it took about 8 and 10 hours respectively at the refrigerator and the freezer mode. Then, without external power supply, the inner temperature of the cold storage refrigerator has been maintained at $-18{\pm}1^{\circ}C$ during 14 hours at the freezer mode and maintained at $3{\pm}^{\circ}C$ during 34 hours at the refrigerator mode. Just after the end of its valid usage as a refrigerator or a freezer, it took about 6 hours to refreeze the PCM for its reuse. During the test, the ambient temperature was kept at $30^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.329-331
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• 2003

PROSET2000 that is integrated protective management system had developed and used in order to automate the setting process of protective relays in transmission system protection. PROSET2000 have database for relay setting and automated for relay setting program within. This paper proposed PCM current differential relay setting program point of Object Oriented Programming paradigm using Unified Modeling Language about additional relay in PROSET2000. Nevertheless each relay uses same current differential but setting method is different. This paper discribed different thing about setting method of each relay and evaluated more effective and corrective relay setting program using UML.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.96-97
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• 2020

Polymer modified cement mortar (PCM) is commonly used as a repair material. However, in high-temperature environments such as fire, it is more likely to explode than cement mortar. The polymer is thermally decomposed at a high temperature to form a gas, and the gas remaining inside the structure increases the internal pressure to generate a burst. When an spalling occurs, the coating is peeled off and dropped, and high temperature is transmitted to the inside of the structure. In severe cases, even the reinforcing bar is exposed, which can lead to the collapse of the structural member due to severe loss of strength. In this study, in order to reduce spalling of PCM, a fiber mixing method was selected from the refractory method to find an appropriate blending ratio of fibers and polymers.

• 한국산업보건학회지
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• 제19권3호
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• pp.213-232
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• 2009

This document was prepared to review and summarize the analytical methods for airborne and bulk asbestos. Basic principles, shortcomings and advantages for asbestos analytical instruments using phase contrast microscopy(PCM), polarized light microscopy(PLM), X-ray diffractometer (XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) were reviewed. Both PCM and PLM are principal instrument for airborne and bulk asbestos analysis, respectively. If needed, analytical electron microscopy is employed to confirm asbestos identification. PCM is used originally for workplace airborne asbestos fiber and its application has been expanded to measure airborne fiber. Shortcoming of PCM is that it cannot differentiate true asbestos from non asbestos fiber form and its low resolution limit ($0.2{\sim}0.25{\mu}m$). The measurement of airborne asbestos fiber can be performed by EPA's Asbestos Hazard Emergency Response Act (AHERA) method, World Health Organization (WHO) method, International Standard Organization (ISO) 10312 method, Japan's Environmental Asbestos Monitoring method, and Standard method of Indoor Air Quality of Korea. The measurement of airborne asbestos fiber in workplace can be performed by National Institute for Occupational Safety and Health (NIOSH) 7400 method, NIOSH 7402 method, Occupational Safety and Health Administration (OSHA) ID-160 method, UK's Health and Safety Executive(HSE) Methods for the determination of hazardous substances (MDHS) 39/4 method and Korea Occupational Safety and Health Agency (KOSHA) CODE-A-1-2004 method of Korea. To analyze the bulk asbestos, stereo microscope (SM) and PLM is required by EPA -600/R-93/116 method. Most bulk asbestos can be identified by SM and PLM but one limitation of PLM is that it can not see very thin fiber (i.e., < $0.25{\mu}m$). Bulk asbestos analytical methods, including EPA-600/M4-82-020, EPA-600/R-93/116, OSHA ID-191, Laboratory approval program of New York were reviewed. Also, analytical methods for asbestos in soil, dust, water were briefly discussed. Analytical electron microscope, a transmission electron microscope equipped with selected area electron diffraction (SAED) and energy dispersive X-ray analyser(EDXA), has been known to be better to identify asbestiform than scanning electron microscope(SEM). Though there is no standard SEM procedures, SEM is known to be more suitable to analyze long, thin fiber and more cost-effective. Field emission scanning electron microscope (FE-SEM) imaging protocol was developed to identify asbestos fiber. Although many asbestos analytical methods are available, there is no method that can be applied to all type of samples. In order to detect asbestos with confidence, all advantages and disadvantages of each instrument and method for given sample should be considered.

• 설비공학논문집
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• 제17권3호
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• pp.223-231
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• 2005

When test tubes for PCM with melting point lower than a room temperature are installed vertically as the T-history method proposes, there exists a temperature distribution in the longitudinal direction by natural convection, which lowers the precision of measured heat-of-fusion. The purpose of the present work is to improve the precision by arranging the test tubes horizontally, while maintaining the simplicity and convenience. Assuming that the amount of heat transfer is very small through the vapor space formed in the upper part of the tubes by volumetric change, the obtained value by the T-history method using the latent heat period bounded by two inflection points is in good agreement with that of the literature. Also, the scattering of measured values by the proposed method decreases markedly compared to that of vertical positioning.

• 한국음향학회지
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• 제11권4호
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• pp.36-44
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• 1992

리던던시(redundancy)가 존재하는 신호의 데이타 압축을 위한 한 방법으로 비균일 표본화 방법이 연구되어져 왔다. 그런데 많은 리던던시가 존재한다고 알려진 음성신호에 기존의 비균일 표본화 방법을 그대로 적용하며, 데이타량이 PCM과 같은 균일 표본화에 의한 것에 필적하게 되거나 오히려 많아지게 된다. 이 문제를 해결하기 위하여 본 논문에서는 음성의 인지측면에서 리던던트한 샘플을 제거하는, 극대점과 극소점에서 비균일 표본화하는 방법을 제안한다. 그리고 본 논문에서는 제안된 방법의 성능을 분석하고자, 실험적인 방법으로 압축비관계를 살펴보며, 아울러 묶음구간 처리에 의하여 압축비를 크게 향상 시킬 수 있음을 보인다. 실험결과로써는 8kHz 8-bit PCM신호에 대하여 1.54배, 묶음처리를 한 경우에는 2.88배의 압축비를 얻었다.