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Template-Based Object-Order Volume Rendering with Perspective Projection (원형기반 객체순서의 원근 투영 볼륨 렌더링)

  • Koo, Yun-Mo;Lee, Cheol-Hi;Shin, Yeong-Gil
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.7
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    • pp.619-628
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    • 2000
  • Abstract Perspective views provide a powerful depth cue and thus aid the interpretation of complicated images. The main drawback of current perspective volume rendering is the long execution time. In this paper, we present an efficient perspective volume rendering algorithm based on coherency between rays. Two sets of templates are built for the rays cast from horizontal and vertical scanlines in the intermediate image which is parallel to one of volume faces. Each sample along a ray is calculated by interpolating neighboring voxels with the pre-computed weights in the templates. We also solve the problem of uneven sampling rate due to perspective ray divergence by building more templates for the regions far away from a viewpoint. Since our algorithm operates in object-order, it can avoid redundant access to each voxel and exploit spatial data coherency by using run-length encoded volume. Experimental results show that the use of templates and the object-order processing with run-length encoded volume provide speedups, compared to the other approaches. Additionally, the image quality of our algorithm improves by solving uneven sampling rate due to perspective ray di vergence.

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Anomalous Effect of Hydrogenation on the Optical Characterization In0.5Ga0.5As Quantum Dot Infrared Photodetectors (MBE로 성장된 In0.5Ga0.5As/GaAs 양자점 원적외선 수광소자의 수소화 처리가 광학적 특성에 미치는 특이영향)

  • Lim J.Y.;Song J.D.;Choi W.J.;Cho W.J.;Lee J.I.;Yang H.S.
    • Journal of the Korean Vacuum Society
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    • v.15 no.2
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    • pp.223-230
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    • 2006
  • We have investigated the characteristics of hydrogen (H) plasma treated quantum dot infrared photodetectors (QDIPs). The structure used in this study consists of 3 stacked, self assembled In0.5Ga0.5As/GaAs QD layer separated by GaAs barrier layers that were grown by molecular beam epitaxy. Optical characteristics of QDIPs, such as photoluminescence (PL) spectra and photocurrent spectra, have been studied and compared with each other for the as grown and H plasma treated QDIPs. H plasma treatment, resulted in the splitting of PL peak, which can be attributed to the redistribution of the size of QDs. The activation energies estimated from the temperature dependence of integrated PL intensity for as grown and H plasma treated QDIPs are found to be in good agreement with those determined from corresponding peaks of photocurrent spectra. It is also noted that photocurrent is detected up to 130 K for the H plasma treated QDIP, suggesting the future possibility for the development of infrared photodetectors with high temperature operation.

Passivation property of Al2O3 thin film for the application of n-type crystalline Si solar cells (N-type 결정질 실리콘 태양전지 응용을 위한 Al2O3 박막의 패시베이션 특성 연구)

  • Jeong, Myung-Il;Choi, Chel-Jong
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.3
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    • pp.106-110
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    • 2014
  • The passivation property of Al2O3 thin film formed using atomic layer deposition (ALD) for the application of crystalline Si solar cells was investigated using microwave photoconductance decay (μ-PCD). After post-annealing at 400C for 5 min, Al2O3 thin film exhibited the structural stability having amorphous nature without the interfacial reaction between Al2O3 and Si. The post-annealing at 400C for 5 min led to an increase in the relative effective lifetime of Al2O3 thin film. This could be associated with the field effective passivation combined with surface passivation of textured Si. The capacitance-voltage (C-V) characteristics of the metal-oxide-semiconductor (MOS) with Al2O3 thin film post-annealed at 400C for 5 min was carried out to evaluate the negative fixed charge of Al2O3 thin film. From the relationship between flatband voltage (VFB) and equivalent oxide thickness (EOT), which were extracted from C-V characteristics, the negative fixed charge of Al2O3 thin film was calculated to be 2.5×1012cm2, of which value was applicable to the passivation layer of n-type crystalline Si solar cells.

New Gain Function Based on Attenuation Characteristics of Ballast Track for GPR Analysis (GPR 분석을 위한 자갈궤도 자갈의 감쇄특성을 이용한 이득함수 개발)

  • Shin, Jihoon;Choi, Yeongtae;Jang, SeungYup
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.4
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    • pp.13-21
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    • 2017
  • Ballasted track has been used as track system for more than 100 years. Ballasted track has advantages of low construction cost, flexible maintenance, low noise and vibration, and so on. However, ballasted track leads to continuous settlement which causes maintenance. Recently, increase in speed, traffic volume, and weight of train requires more frequent maintenance. Fouling, well-known phenomenon of accumulation of fine materials due to intrusion of subgrade and breakage of ballast materials, expedites the settlement (i.e., irregular settlement) of track. Ground Penetrating Radar (GPR) can be one of non-destructive tools that can evaluate fouling level of ballast. In this paper, a gain function based on the attenuation characteristics of ballast material is suggested in conjunction with Hilbert transform. Lab box tests and full-scale tests indicate that the suggested method reasonably classifies clean, fouled layers, and subgrade. However, additional study to eliminate effect of sleeper and to include the scattering features of the electromagnetic wave in ballast voids should be required in order to enhance the accuracy.

Uplift Testing and Load-transfer Characteristics of Model Drilled Shafts in Compacted Weathered Granite Soils (화강풍화토 지반에 타설된 소형 현장 타설 말뚝의 인발시험 및 하중 전이 특성)

  • 임유진;서석현
    • Journal of the Korean Geotechnical Society
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    • v.18 no.4
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    • pp.105-117
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    • 2002
  • In the design of foundations for the super-structures such as transmission towers and oil-platforms, the foundations must be considered as a medium to resist cyclic tensile forces. In this study, the uplift capacity of the drilled shaft used as the medium resisting to this pattern of forces is investigated by performing cyclic uplift test of a small model-drilled shaft constructed in compacted granite soil in a steel chamber. In this test, the behavioral difference between a pile loaded on the top of the pile and a pile loaded at the bottom of the pile was investigated intensively. The load transfer curves obtained from the test were investigated by changing the confining pressure in the chamber. The load tests also included creep test and cyclic test. It is found from the tests that uplift capacity of the shaft loaded at the bottom is greater than that of the shaft loaded on the top of the pile. It is found also from the creep test that the pile loaded at the bottom was more stable than the shaft loaded on the top. If a pile loaded at the bottom is pre-tensioned, the pile will be most effective to the creep displacement. It is found also from the cyclic tests that apparent secant modulus obtained in a cycle of the load increases with the number of cycles.

A Case Study on the Development Process of the Industrial Districts in Third Italy: Modena and Mirandola (제3이탈리아 산업지구 발전과정에 대한 비교 연구: 모데나와 미란돌라를 중심으로)

  • 권오혁
    • Journal of the Economic Geographical Society of Korea
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    • v.6 no.1
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    • pp.21-44
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    • 2003
  • It is the Third Italy's industrial districts that is emerging as effective strategies for regional economic development since 1970' s. Compared with mass production system, it's production system is characterized the cooperative networks of a number of enterprise specialized in specific sector or process. This work will analysis the course of growth and industrial characteristics of Modena engineering industrial district and Mirandola bio-industrial district as the exemplary industrial district, so elucidate new principle of building industrial space named development of industrial districts. This work point out three characteristics which these industrial districts have. First, these districts have the production system based vertical dis-integration and specialization among enterprise like general industrial districts in Third Italy. This factor make Modena and Mirandola's production system coupled with specialized enterprise in coping with various demand of consumer. Second, technological innovation is very important factor in growing industrial districts. This factor contributes these two districts to have developed as the competitive industrial clusters in the world. Last point is the difference of local governance by the two city governments. Modena city government has made a lot of industrial spaces but in Mirandola the leading enterprise has contributed to shape the industrial district.

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Systematic Approach to The Extraction of Effective Region for Tongue Diagnosis (설진 유효 영역 추출의 시스템적 접근 방법)

  • Kim, Keun-Ho;Do, Jun-Hyeong;Ryu, Hyun-Hee;Kim, Jong-Yeol
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.6
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    • pp.123-131
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    • 2008
  • In Oriental medicine, the status of a tongue is the important indicator to diagnose the condition of one's health like the physiological and the clinicopathological changes of internal organs in a body. A tongue diagnosis is not only convenient but also non-invasive, and therefore widely used in Oriental medicine. However, the tongue diagnosis is affected by examination circumstances like a light source, patient's posture, and doctor's condition a lot. To develop an automatic tongue diagnosis system for an objective and standardized diagnosis, segmenting a tongue region from a facial image captured and classifying tongue coating are inevitable but difficult since the colors of a tongue, lips, and skin in a mouth are similar. The proposed method includes preprocessing, over-segmenting, detecting the edge with a local minimum over a shading area from the structure of a tongue, correcting local minima or detecting the edge with the greatest color difference, selecting one edge to correspond to a tongue shape, and smoothing edges, where preprocessing consists of down-sampling to reduce computation time, histogram equalization, and edge enhancement, which produces the region of a segmented tongue. Finally, the systematic procedure separated only a tongue region from a face image with a tongue, which was obtained from a digital tongue diagnosis system. Oriental medical doctors' evaluation for the results illustrated that the segmented region excluding a non-tongue region provides important information for the accurate diagnosis. The proposed method can be used for an objective and standardized diagnosis and for an u-Healthcare system.

Theoretical Study on Observed Heat of Ligation for Iron(Ⅱ) and Nickel(Ⅱ) Octahedral Complexes (팔면체형 Fe(Ⅱ)와 Ni(Ⅱ)착물의 실측 리간드화열에 관한 이론적 연구)

  • Kim, Jung Sung;Choi, Jin Tae;Song, Young Dae;Cho, Tae Sub
    • Journal of the Korean Chemical Society
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    • v.43 no.2
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    • pp.141-149
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    • 1999
  • The correlation was investigated between the observed heat of ligation and calculated quantum chemical quantities for octahedral [M(H2O)6x(NH3)x]2+(M=Fe(II),Ni(II)) complexes by EHMO(Extended Huckel Molecular Orbital) and ZINDO/1(Zerner's Intermediate Neglected of Differential Overlap)method. The net charge of Fe2+ and Ni2+ ion of octahedral [M(H2O)6x(NH3)x]2+(M=Fe(II),Ni(II)) complexes(x=O, 1, …, 6) decreased with substituting NH3 for H2O molecules. It has found that a good correlation exists between the observed heat of ligation and the calculated quantum chemical quantities such as net charge of central atom, enthalpy of formation, and total dissociation energy. From this finding, we have obtained the following semiempirical linear equation ΔHobs=0.2858qFe+0.8813(r=0.97),ΔHobs=0.8981qNi+1.7929(r=0.95),ΔHobs=0.0031Hf(Fe)+0.5725(r=0.97),ΔHobs=0.0095Hf(Ni)+0.9193(r=0.97),ΔHobs=0.0476Ediss(Fe)+0.6434(r=0.94),ΔHobs=0.1401Ediss(Ni)+1.1393(r=0.93).

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Development of Sag and Tension Sensitivity Estimation Method for Configuration Control under PPWS Erection in a Suspension Bridge (현수교 PPWS 가설중 형상관리를 위한 PPWS 새그 및 장력민감도 산정법 개발)

  • Jeong, Woon;Seo, Ju Won;Lee, Won Pyo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.5A
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    • pp.255-266
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    • 2012
  • Main cable of a suspension bridge is the important member which shows the overall structure integrity at bridge completion. Configuration of main cable is a free hanging state at cable erection completion and is different from that at bridge completion supporting the dead loads such as hanger, girder, and so on. Accordingly, the configuration control under cable erection is considerably significant because the configuration at cable erection completion has direct influence on that at bridge completion. That is performed by sag adjustments at center, side span and tension adjustments at anchor span. The former needs the sag sensitivity which represents the control quantity of strand length corresponding to that of sag. The latter requires the tension sensitivity which shows the change of strand tension according to that of strand temperature. In this study, the fundamental equations of cable were derived with the assumption of either catenary or parabola shape, the differential-related equations using chain rule on horizontal tension were drawn from those and finally the estimation methods of the sag / tension sensitivity were proposed from both those. The nonlinear numerical analysis flow charts of sag sensitivity based on the catenary equations were proposed and the sag sensitivities grounded on the differential-related equations were compared with the results using them for various parameters of sag change. Also, considering the combinations of sag change parameters, the calculation method of the final variation for the cable sag was suggested. For the real suspension bridge under construction with PPWS method, the sag/tension sensitivity were estimated considering the construction conditions like the change of PPWS length, PPWS temperature, bridge span, etc.. We hope that this study will be a systematic guideline for the configuration control under main cable erection and improved highly by field verification in the real bridge site.

Uncertainty Assessment of CANDU Void Reactivity using MCNP-4C with ENDF/B-VII(I) (ENDF/B-VII기반 MCNP-4C를 이용한 CANDU-6 기포반응도 불확실성 평가(I))

  • Hong, S.T.;Kwon, T.A.;Lee, Y.J.;Oh, S.K.;Lee, S.K.;Kim, M.W.
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2008.04a
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    • pp.69-75
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    • 2008
  • 기포반응도는 월성발전소를 비롯한 CANDU형 원자로의 주된 안전성 쟁점사안으로 끊임없이 논의되어 왔다. 이는 설계기준사고가 노심에서 열에너지 불균형이 원인이 되어 기준이상의 핵연료 파손과 방사성물질 누출로 발전할 위험이 있는 사건들로 정의될 때, 사건 진행 과정에 기포반응도 증가는 조기에 운전중단을 실패할 경우 출력폭주로 이어지므로 사건의 결말이 중대사고로 전환될 위험이 크기 때문이다. 본 연구는 공개된 최신 핵자료인 ENDF/B-VII.0를 NJOY.99로 처리한 연속에너지 반응단면적 라이브러리를 구축하고 MCNP-4C에 접속하여 37봉 천연우라늄 핵연료다발의 표준노심격자에 대한 기포반응도를 시뮬레이션하여, 지금까지 각종문헌에 제시된 값들과 비교, 종합하므로 내제된 불확실성을 추정하는 내용이다. ENDF/B-VII.0 기반 MCNP-4C의 CANDU 노심격자 모델은 동일한 핵자료와 핵종농도를 사용한 WIMS-IAEA 모델과 비교할 때, 초기 노심의 임계도 오차 약 3.51mk가 연소 진행에 따라 7.5×104mk/MWD/teU의 비율로 감소하는 것으로 나타났다. 또한 MCNP-4C 예측기포반응도는 초기노심에서 기포율 50% 및 100%에 대해 각각 8.38 및 15.96mk, 평형노심에서 7.68 및 14.72mk로 계산된다. 이는 월성 2, 3, 4 FSAR의 초기노심 및 평형노심에서 100% 기포상태에 대한 값, 약15.0 및 10.6mk와 비교할 때, 초기노심은 약 1.0mk 평형노심은 약4, 1mk 보수적이지만, 다른 연구결과들과는 최대오차 ±12mk 이내에서 잘 일치하는 것으로 평가되었다. 본 연구는 CANDU 노심의 기포반응도 불확실성 요인의 규명 및 영향평가를 위한 노력의 일부로서 앞으로 감속재의 붕산농도 변화, 감속재 및 냉각재의 중수 순도 변화, 기기노화에 의한 격자 구조 및 물성 변화, 중성자속 및 출력 분포 불균형, 반응도조절장치의 위치, 등 주요 설계변수의 변화에 대한 반응도영향 분석연구를 계속할 계획이다.

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