• International Journal of Naval Architecture and Ocean Engineering
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• 제9권6호
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• pp.705-719
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• 2017

Progressive Collapse Method (PCM) has been broadly applied to predict moment-carrying capacity of a hull girder, however accuracy of PCM has not been much studied. Accuracy of PCM is known to be dependent on how Load-Shortening and -Elongation (LSE) curve of a structural units are well predicted. This paper presents a new procedure to determine LSE datum based on box girder Finite Element Analyses (FEAs) instead of using finite element model of stiffened panels. To verify reliability of FEA results, the simple box girder collapse test results are compared with FEA results of same box girders. It reveals one frame-based box girder model is sufficiently accurate in terms of ultimate strengths of the box girders. After extracting LSE data from the box girders, PCM-based moment-carrying capacities are compared with those from FEAs of the box girders. PCM results are found to be equivalent to FEAs in terms of moment-carrying capacity if accurate LSE data are secured. The new procedure is applied to well-known 1/3 scaled frigate full section. Very excellent moment-carrying capacity of frigate hull section is obtained from PCM with LSE data from box girder FEAs.

• Nuclear Engineering and Technology
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• 제16권2호
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• pp.70-79
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• 1984

대형 고속증식로용 핵계산 체제(KAERI-26군 단면적 library/1DX/2DB)를 이용하여 SUPER-PHE-NIX I 평형 노심의 초기상태에서의 diagrid 및 Pad팽창에 대한 반응도 계수를 계산, 검토하였다. 노심은 R-Z등가 model로 묘사하고, 2차원 다군 확산 이론 전산코드인 2DB를 사용하여 임계도를 계산하였다. 기초계산으로서 반경방향 및 축방향 균일 괭창에 대한 반응도 계산과 노심구성물질의 원자수 밀도 변화와 노심체적 변화에 대한 반응도 변화량계산을 수행하였다. 균일 팽창으로 고려한 diagrid팽창에 대한 반응도 계수는 -0.553pcm/mil로 계산되었다. 한편 반응도의 온도계수는 -1.0766pcm/$^{\circ}C$로 환산되어 프랑스 발표치 -1.09pcm/$^{\circ}C$와 1.2%오차내로 일치하였다. Diagrid 팽창효과 졔산방법을 활용하여 노심의 불균일 팽창을 유발하는 pad팽창에 대한 반응도 계수 계산을 수행한 바 매우 유용함을 알았다. Pad팽창에 대한 반응도 계수는 평균팽창 model의 경우 -0.2743pcm/mi1, pancake집적 model의 경우 -0.2786pcm/mi1로 각각 계산되었다. 또한 자유팽창 노심에서의 온도변화에 따른 pad 팽창에 대한 반응도 계수는 각 model에 대하여 -0.5766pcm/$^{\circ}C$, -0.5858pcm/$^{\circ}C$로 계산되어 프랑스 발표치 -0.574pcm/$^{\circ}C$와 2% 오차내로 일치하였다.

• Journal of information and communication convergence engineering
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• 제15권1호
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• pp.49-52
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• 2017

Ganglion cysts are benign soft tissues usually encountered in the wrist. In this paper, we propose a method to extract a ganglion cyst region from ultrasonography images by using image segmentation. The proposed method using the possibilistic c-means (PCM) clustering method is applicable to ganglion cyst extraction. The methods considered in this thesis are fuzzy stretching, median filter, PCM clustering, and connected component labeling. Fuzzy stretching performs well on ultrasonography images and improves the original image. Median filter reduces the speckle noise without decreasing the image sharpness. PCM clustering is used for categorizing pixels into the given cluster centers. Connected component labeling is used for labeling the objects in an image and extracting the cyst region. Further, PCM clustering is more robust in the case of noisy data, and the proposed method can extract a ganglion cyst area with an accuracy of 80% (16 out of 20 images).

• KIEAE Journal
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• 제15권3호
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• pp.43-48
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• 2015

Purpose: Recently, many countries around the world are actively looking for the ways to make full use of natural energy sources and also develop and apply an environmentally friendly system designed to save building energy consumption. Under these circumstances, this study intended to determine the applicability and energy saving effect by deriving the indoor thermal performance characteristics and the PCM temperature appropriate for a double skin façade to reduce indoor energy consumption through the application of different PCM temperatures to double skin façade and perform a performance evaluation depending on the application or non-application of PCM to a double skin façade. Method: For this study, the physical variables of the double skin façade with PCM were configured through a preliminary examination based on an experimental measurement, and experimental measurements were taken with a total of 7 types of mockup cases: Type-1 (Basic), the basic double skin façade, Type-2 (PCM $18^{\circ}C$) which was applied to the inner skin of the double skin façade depending on the phase-change temperature of PCM, Type-3 (PCM $20^{\circ}C$), Type-4 (PCM $22^{\circ}C$), Type-5 (PCM $24^{\circ}C$), Type-6 (PCM $26^{\circ}C$), and Type-7 (PCM $28^{\circ}C$) with reference to the data analysis of the basic double skin façade which preceded this study, to analyze the indoor thermal performance of the double skin façade depending on PCM temperature and the installation or non-installation of a double skin façade applying PCM based on the selected unit space. Result: Indoor thermal performance was analyzed depending on the PCM temperature applicable to double skin façade, and the analysis of heating energy reduction showed that Type-2 (PCM $18^{\circ}C$) gained 15.9% more heat compared with Type-1 (Basic) and secondly, Type-3 (PCM $20^{\circ}C$) gained 11.5% more heat. Based on these findings, it is deemed possible that the use of energy for heating can be reduced when heat coming indoors increases during the heating period, and the appropriate temperature for PCM applied to the inner skin of a double skin façade to reduce heating energy in winter, Type-2 (PCM $18^{\circ}C$) showed the highest efficiency and Type-3 (PCM $20^{\circ}C$) was also deemed appropriate.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (2)
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• pp.790-792
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• 2004

본 논문은 PCM(Possibilistic C-Means) 알고리즘과 베이시안 분류 알고리즘을 통합한 고해상도 위성영상의 효과적인 분류방법을 제안하였다. 제안된 알고리즘은 학습데이터를 참고로 하여 PCM 알고리즘을 반복적인 과정 없이 수행한다. 각 분류항목별로 분류된 데이터에서 평균내부거리 내부에 해당되는 데이터들을 선정하여 각 항목별 비율을 구한 후 베이시안 분류기법의 사전확률로 적용하여 분류를 수행한다 PCM 알고리즘은 각 데이터와 특정 클러스터와의 거리에 소속도를 부여하는 퍼지 C-Means 알고리즘과 달리 소속도를 각 데이터와 클러스터 중심간의 절대거리에 의존하는 방법으로 퍼지 C-Means 알고리즘이 가지는 상대성 문제를 해결하였다. 제안된 분류 기법을 고해상도 다중분광 데이터인 IKONOS 위성영상에 적용하여 분류를 수행한 후 최대우도 분류기법과 비교한다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권7호
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• pp.779-784
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• 2005

This paper presents the theory of similarity transformations applied to the momentum and energy equations for laminar, forced, external boundary layer flow over a horizontal flat plate which leads to a set of non-linear, ordinary differential equations of phase change material slurry(PCM Slurry). The momentum and energy equation set numerically to obtain the non-dimensional velocity and temperature profiles in a laminar boundary layer are solved. The heat transfer characteristics of PCM slurry was numerically investigated with similar method. It is clarified that the similar solution method of Newtonian fluid can be used reasonably this type of PCM slurry which has low concentration. The data of local wall heat flux and convective heat transfer coefficient of PCM slurry are higher than those of water more than 150$\~$200$\%$, approximately.

• International Journal of Air-Conditioning and Refrigeration
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• 제12권4호
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• pp.206-213
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• 2004

Cycle test for developed phase change material (PCM) is necessary in order to assess the variation of latent heat, which decreases with time by deterioration. T-history method and measurement using heat-flux meter are appropriate for the cycle test in a tube filled with PCM because they do not need an extraction of sample in measuring heat of fusion. In the present study, these methods were applied to a PCM having a melting point below a room temperature, different to the past studies for PCMs melting above a room temperature. As a result of experiment using pure water as specimen, we can obtained rea-sonable values for heat of fusion.

• KIEAE Journal
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• 제14권4호
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• pp.133-138
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• 2014

The present study was carried out to assess the basic material properties and thermal behavior of light-weight foamed concrete panel mixed with PCM (Phase Changing Material). To do so, this study fabricated light-weight foamed concrete (1.0kg/m3) in pre-foaming method and mixed it with PCM micro capsule of 1-dodecanol and melamine to examine its physical and thermal properties. The results confirmed strength reinforcement effect by proper replacement ratio of fly-ash, which is an industrial by-product, and PCM. In addition, it found out that PCM-mixed light-weight foamed concrete had time delay and temperature reduction effect within the range of PCM phase transition according to the rise of outdoor temperature. It was also observed that the insulation performance of PCM-mixed light-weight foamed concrete was more dependent upon thickness than PCM replacement ratio.

• 한국구조물진단유지관리공학회 논문집
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• 제21권4호
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• pp.110-115
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• 2017

이 연구는 상변화 물질(저온 PCM)을 포함한 경량 콘크리트의 기계적 성능을 검토하기 위해 수행되었다. Micro capsulised PCM은 wax type core와 melamine based wall으로 구성되어있다. 또한, 단일 종류의 PCM의 경우, Vermiculite에 파라핀 왁스를 삽입하고 그 표면을 멜라민 수지로 코팅 하였다. 계면 중합은 1-dodecanol(핵심 물질)과 물(용매) 사이의 표면에서 중합반응이 일어나 벽 물질을 형성한다는 원리에 기반한다. 경량 콘크리트는 10 MPa의 압축 강도, 1.5 MPa의 인장 강도 및 1.0 kg/L의 절건 밀도를 가지며 10 %, 20 % 또는 30 %의 PCM을 포함하고 있다. 이를 위해 예비 배합으로 경량 기포 콘크리트($1.0kg/m^3$)를 제조 한 후 1-dodecanol 및 멜라민의 PCM 마이크로 캡슐과 혼합하여 그 물성을 조사하였다.

• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.2069-2074
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• 2007

The 27Al multiple quantum magic angle spinning (MQMAS) nuclear magnetic resonance (NMR) spectra of mordenite zeolites were simulated using the point charge model (PCM). The spectra simulated by the PCM considering nearest neighbor atoms only (PCM-n) or including atoms up to the 3rd layer (PCM-m) were not different from those generated by the Hartree-Fock (HF) molecular orbital calculation method. In contrast to the HF and density functional theory methods, the PCM method is simple and convenient to use and does not require sophisticated and expensive computer programs along with specialists to run them. Thus, our results indicate that the spectral simulation of the 27Al MQMAS NMR spectra obtained with the PCM-n is useful, despite its simplicity, especially for porous samples like zeolites with large unit cells and a high volume density of pores. However, it should be pointed out that this conclusion might apply only for the atomic sites with small quadrupole coupling constants.