• Title/Summary/Keyword: Boundary conditions

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A Real-Time Stereoscopic Image Conversion Method Based on A Single Frame (단일 프레임 기반의 실시간 입체 영상 변환 방법)

  • Jung Jae-Sung;Cho Hwa-Hyun;Choi Myung-Ryul
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.43 no.1 s.307
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    • pp.45-52
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    • 2006
  • In this paper, a real-time stereoscopic image conversion method using a single frame from a 2-D image is proposed. The Stereoscopic image is generated by creating depth map using vortical position information and parallax processing. For a real-time processing of stereoscopic conversion and reduction of hardware complexity, it uses image sampling, object segmentation by standardizing luminance and depth map generation by boundary scan. The proposed method offers realistic 3-D effect regardless of the direction, velocity and scene conversion of the 2-D image. It offers effective stereoscopic conversion using images suitable conditions assumed in this paper such as recorded image at long distance, landscape and panorama photo because it creates different depth sense using vertical position information from a single frame. The proposed method can be applied to still image because it uses a single frame from a 2-D image. The proposed method has been evaluated using visual test and APD for comparing the stereoscopic image of the proposed method with that of MTD. It is confirmed that stereoscopic images conversed by the proposed method offers 3-D effect regardless of the direction and velocity of the 2-D image.

MAC-Layer Error Control for Real-Time Broadcasting of MPEG-4 Scalable Video over 3G Networks (3G 네트워크에서 MPEG-4 스케일러블 비디오의 실시간 방송을 위한 실행시간 예측 기반 MAC계층 오류제어)

  • Kang, Kyungtae;Noh, Dong Kun
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.3
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    • pp.63-71
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    • 2014
  • We analyze the execution time of Reed-Solomon coding, which is the MAC-layer forward error correction scheme used in CDMA2000 1xEV-DO broadcast services, under different air channel conditions. The results show that the time constraints of MPEG-4 cannot be guaranteed by Reed-Solomon decoding when the packet loss rate (PLR) is high, due to its long computation time on current hardware. To alleviate this problem, we propose three error control schemes. Our static scheme bypasses Reed-Solomon decoding at the mobile node to satisfy the MPEG-4 time constraint when the PLR exceeds a given boundary. Second, dynamic scheme corrects errors in a best-effort manner within the time constraint, instead of giving up altogether when the PLR is high; this achieves a further quality improvement. The third, video-aware dynamic scheme fixes errors in a similar way to the dynamic scheme, but in a priority-driven manner which makes the video appear smoother. Extensive simulation results show the effectiveness of our schemes compared to the original FEC scheme.

Evaluation of an Effective Load Transfer System Applied to a Simple Model of a Wall Frame Structural System (단순 모델을 사용한 추상복합 건물의 효율적인 전이 시스템에 관한 연구)

  • 정영일;윤석한;홍원기;김희철
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.3
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    • pp.23-29
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    • 2002
  • A wall-frame type structural system has been widely used to make full use of a limited land in large cities to satisfy the several functional requirement in one building. However, this type of hybrid structure brought some problems due to the vertical discontinuity of a structural system. The response of a wall-frame type structural system having a deep transfer girder was observed. An arch system was introduced to replace the deep transfer girder. The adequacy of an arch system was observed for the various boundary conditions of a system. The proposed system was compared to a general transfer girder system by applying both gravity load and lateral load. It was observed that an arch system fairly distributes the stress without concentrating stress at a certain location of a system differently from the current transfer girder system. The moment decrement effect of a column can also be obtained by eliminating the large mass of a transfer girder. Also it was investigated that an arch system is more economical and effective than the current transfer girder system.

An Experimental Study on Flow Distributor Performance with Single-Train Passive Safety System of SMART-ITL (SMART-ITL 1 계열 피동안전계통을 이용한 유동분사기 성능에 대한 실험연구)

  • Ryu, Sung Uk;Bae, Hwang;Yang, Jin Hwa;Jeon, Byong Guk;Yun, Eun Koo;Kim, Jaemin;Bang, Yoon Gon;Kim, Myung Joon;Yi, Sung-Jae;Park, Hyun-Sik
    • Journal of Energy Engineering
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    • v.25 no.4
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    • pp.124-132
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    • 2016
  • In order to estimate the effect of flow distributors connected to an upper nozzle of CMT(Core Makeup Tank) on the thermal-hydraulic characteristics in the tank, a simplified 2 inch Small Break Loss of Coolant Accident(SBLOCA) was simulated by skipping the decay power and Passive Residual Heat Removal System(PRHRS) actuation. The CMT is a part of safety injection systems in the SMART (System Integrated Modular Advanced Reactor). Each test was performed with reliable boundary conditions. It means that the pressure distribution is provided with repeatable and reproducible behavior during SBLOCA simulations. The maximum flow rates were achieved at around 350 seconds after the initial opening of the isolation valve installed in CMT. After a short period of decreased flow rate, it attained a steady injection flow rate after about 1,250 seconds. This unstable injection period of the CMT coolant is due to the condensation of steam injected into the upper part of CMT. The steady injection flow rate was about 8.4% higher with B-type distributor than that with A-type distributor. The gravity injection during hot condition tests were in good agreement with that during cold condition tests except for the early stages.

Place Assimilation in OT

  • Lee, Sechang
    • Proceedings of the KSPS conference
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    • 1996.10a
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    • pp.109-116
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    • 1996
  • In this paper, I would like to explore the possibility that the nature of place assimilation can be captured in terms of the OCP within the Optimality Theory (Mccarthy & Prince 1999. 1995; Prince & Smolensky 1993). In derivational models, each assimilatory process would be expressed through a different autosegmental rule. However, what any such model misses is a clear generalization that all of those processes have the effect of avoiding a configuration in which two consonantal place nodes are adjacent across a syllable boundary, as illustrated in (1):(equation omitted) In a derivational model, it is a coincidence that across languages there are changes that have the result of modifying a structure of the form (1a) into the other structure that does not have adjacent consonantal place nodes (1b). OT allows us to express this effect through a constraint given in (2) that forbids adjacent place nodes: (2) OCP(PL): Adjacent place nodes are prohibited. At this point, then, a question arises as to how consonantal and vocalic place nodes are formally distinguished in the output for the purpose of applying the OCP(PL). Besides, the OCP(PL) would affect equally complex onsets and codas as well as coda-onset clusters in languages that have them such as English. To remedy this problem, following Mccarthy (1994), I assume that the canonical markedness constraint is a prohibition defined over no more than two segments, $\alpha$ and $\beta$: that is, $^{*}\{{\alpha, {\;}{\beta{\}$ with appropriate conditions imposed on $\alpha$ and $\beta$. I propose the OCP(PL) again in the following format (3) OCP(PL) (table omitted) $\alpha$ and $\beta$ are the target and the trigger of place assimilation, respectively. The '*' is a reminder that, in this format, constraints specify negative targets or prohibited configurations. Any structure matching the specifications is in violation of this constraint. Now, in correspondence terms, the meaning of the OCP(PL) is this: the constraint is violated if a consonantal place $\alpha$ is immediately followed by a consonantal place $\bebt$ in surface. One advantage of this format is that the OCP(PL) would also be invoked in dealing with place assimilation within complex coda (e.g., sink [si(equation omitted)k]): we can make the constraint scan the consonantal clusters only, excluding any intervening vowels. Finally, the onset clusters typically do not undergo place assimilation. I propose that the onsets be protected by certain constraint which ensures that the coda, not the onset loses the place feature.

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Interannual variabilities of the East Asia precipitation associated with tropical and subtropical sea surface temperature (열대 및 아열대 SST에 관련된 동아시아 강우량의 경년 변동성)

  • Ha, Kyung-Ja
    • Journal of Environmental Science International
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    • v.4 no.5
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    • pp.28-28
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    • 1995
  • The aim of the present study is to investigate the interannual variabilities of the East Asia monsoon rainfall associated with the global sea surface temperature anomaly(SSTA). For this study, the summer rainfall(from June to August) over the twenty-eight period of 1961-1988 were analyzed with being divided by nine-subregions over East Asia including Korea, China and Japan. From the analysis of the principal modes explaining the interannual variation, the interannual variabilities of summer rainfalls in South Japan and Korea are larger than those of the other subregions of the East Asia. There is a strong negative correlation between the summer rainfalls of south China and Korea. In this study, the relationship between the summer monsoon of each subregion and SSTs of the tropical NINO regions, of western Pacific warm pool, and of the subtropical ocean were investigated. The longitudinal sections of the lagged cross correlations of the summer rainfal1 anomaly in (a) Korea and (b) south China, and the monthly SSTA in the equatorial(averaged from 65 to 6N) Pacific were analyzed. The negative maximum correlation pattems of Korea''s stammer rainfal1 and SSTs over the eastern Pacific is transfered to positive maximum conrlation over central Pacific region with a biennial periodicity. In South China, the significant positive correlations are found at -12 month lag over the eastern Pacific and maximum negative correlation at 16 month lag over the central Pacific with the quasi-biennial oscillation. But the correlation coefficient reverses completely to that in Korea. In order to investigate the most prevailing interannual variability of rainfall related to the favored SSTA region, the lagged cross correlations between East Asia rainfall and SSTs over the moO regions(NINO 1+2(0-105, 90W-80W), NINO 3(5N-5S, 150W-90W), NINO 4(5N-5S, 160E-l50W) and the western Pacific worm pool (5N-5S, 120E-l60E) were analyzed. Among the lagged cross-correlation cycles in NINO regions, the maximum correlations for the negative lagged months prevail in NINO 1+2 and NINO 3, and the cross correlations for the positive lagged months NINO 4. It is noteworthy that correlation between the western Pacific warm pool SSTA and the monsoon rainfall in Korea and South China have the maximum value at negative 4 month lag. The evolution of the correlation between the East Asia monsoon rainfall and SSTA is linked to the equatorial convective cluster and related to northward propagating situation, and raising the possibility that the East Asia monsoon precipitation may be more fundamentally related to the interaction of intraseasonal oscillations and the sub-regional characteristics including the surface boundary conditions and the behavior of climatological air mass.

Interannual variabilities of the East Asia precipitation associated with tropical and subtropical sea surface temperature (열대 및 아열대 SST에 관련된 동아시아 강우량의 경년 변동성)

  • 하경자
    • Journal of Environmental Science International
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    • v.4 no.5
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    • pp.413-426
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    • 1995
  • The aim of the present study is to investigate the interannual variabilities of the East Asia monsoon rainfall associated with the global sea surface temperature anomaly(SSTA). For this study, the summer rainfall(from June to August) over the twenty-eight period of 1961-1988 were analyzed with being divided by nine-subregions over East Asia including Korea, China and Japan. From the analysis of the principal modes explaining the interannual variation, the interannual variabilities of summer rainfalls in South Japan and Korea are larger than those of the other subregions of the East Asia. There is a strong negative correlation between the summer rainfalls of south China and Korea. In this study, the relationship between the summer monsoon of each subregion and SSTs of the tropical NINO regions, of western Pacific warm pool, and of the subtropical ocean were investigated. The longitudinal sections of the lagged cross correlations of the summer rainfal1 anomaly in (a) Korea and (b) south China, and the monthly SSTA in the equatorial(averaged from 65 to 6N) Pacific were analyzed. The negative maximum correlation pattems of Korea's stammer rainfal1 and SSTs over the eastern Pacific is transfered to positive maximum conrlation over central Pacific region with a biennial periodicity. In South China, the significant positive correlations are found at -12 month lag over the eastern Pacific and maximum negative correlation at 16 month lag over the central Pacific with the quasi-biennial oscillation. But the correlation coefficient reverses completely to that in Korea. In order to investigate the most prevailing interannual variability of rainfall related to the favored SSTA region, the lagged cross correlations between East Asia rainfall and SSTs over the moO regions(NINO 1+2(0-105, 90W-80W), NINO 3(5N-5S, 150W-90W), NINO 4(5N-5S, 160E-l50W) and the western Pacific worm pool (5N-5S, 120E-l60E) were analyzed. Among the lagged cross-correlation cycles in NINO regions, the maximum correlations for the negative lagged months prevail in NINO 1+2 and NINO 3, and the cross correlations for the positive lagged months NINO 4. It is noteworthy that correlation between the western Pacific warm pool SSTA and the monsoon rainfall in Korea and South China have the maximum value at negative 4 month lag. The evolution of the correlation between the East Asia monsoon rainfall and SSTA is linked to the equatorial convective cluster and related to northward propagating situation, and raising the possibility that the East Asia monsoon precipitation may be more fundamentally related to the interaction of intraseasonal oscillations and the sub-regional characteristics including the surface boundary conditions and the behavior of climatological air mass.

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A Theoretical Construction for the Cultural-Political Study on the Place Names in Korea (한국 지명의 문화정치적 연구를 위한 이론의 구성)

  • Kim, Sun-Bae;Ryu, Je-Hun
    • Journal of the Korean Geographical Society
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    • v.43 no.4
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    • pp.599-619
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    • 2008
  • Korean peninsula has a long history and a geopolitical location as a buffer tone, which has provided the conditions for cultural dynamism and diversity across space and time. The changing processes of place names in Korea is considered to be better suited to the study on cultural politics that is interested in the culture wars over the meaning of culture among different social subjects. In order to ensure the legitimacy of cultural politics for the study of place names in Korea, this study attempts to make a theoretical construction based on the concepts of place identity, territorial contestation, and the politics of scale. Cultural and linguistic theories to be best applied to the study of place names in Korea are the theories on Angehm's and Castells' identity, $P{\hat{e}}cheux's$ identification, Hall's decoding, and Voloshinov's ideological sign. Power relations involved in the inclusion and exclusion are necessarily concerned with the process of constructing a place identity or territorial identity by means of a place name, which represents identity and ideology of a social subject. In the examination of this process, it is necessary to take the elements of identity, ideology and power relations into consideration. In this study, therefore, the politics of scale is experimented for its applicability in the study of place name in Korea, which is expected to accommodate concepts of boundary, territory, territoriality and territorialization. In the end, it is suggested in this study that a series of basic and interdisciplinary studies on the cultural politics of place names in a range of area should be undertaken along with the enough theoretical knowledge of cultural politics.

Two-Dimensional Flood Inundation Analysis Resulting from Irrigation Reservoir Failure - Focused on the Real Case with the Minimal Data Set - (농업용 저수지 붕괴에 따른 2차원 홍수범람해석 -계측자료가 부족한 실제사례를 중심으로-)

  • Lee, Jae Young;Kim, Byunghyun;Park, Jun Hyung;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.2
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    • pp.231-243
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    • 2016
  • This study presents the applicability of two-dimensional (2D) flood inundation model by applying to real irrigation reservoir failure with limited available data. The study area is Sandae Reservoir placed in Gyeongju and downstream area of it and the reservoir was failured by piping in 2013. The breach hydrograph was estimated from one-dimensional (1D) hydrodynamic model and the discharge was employed for upstream boundary of 2D flood inundation model. Topography of study area was generated by integrating digital contour map and satellite data, and Cartesian grids with 3m resolution to consider geometry of building, road and public stadium were used for 2D flood inundation analysis. The model validation was carried out by comparing predictions with field survey data including reservoir breach outflow, flood extent, flood height and arrival time, and identifying rational ranges with allowed error. In addition, the applicability of 2D model is examined using different simulation conditions involving grid size, building and roughness coefficient. This study is expected to contributed to analysis of irrigation reservoirs were at risk of a failure and setting up Emergency Action Plan (EAP) against irrigation reservoir failure.

Study for Characteristic of Frictional Heat Transfer in Rotating Brake System (회전을 고려한 브레이크 디스크의 마찰열전달 연구)

  • Nam, Jiwoo;Ryou, Hong Sun;Cho, Seong Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.817-822
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    • 2017
  • The braking system is one of the most important components in vehicles and machines. It must exert a reliable braking force when they are brought to a halt. Generally, frictional heat is generated by converting kinetic energy into heat energy through friction. As the kinetic energy is converted into heat energy, high temperature heat is generated which affects the mechanical behavior of the braking system. Frictional heat affects the thermal expansion and friction coefficient of the brake system. If the temperature is not controlled, the brake performance will be decreased. Therefore, it is important to predict and control the heat generation of the brake. Various numerical analysis studies have been carried out to predict the frictional heat, but they assumed the existence of boundary conditions in the numerical analysis to simulate the frictional heat, because the simulation of frictional heat is difficult and time consuming. The results were based on the assumption that the frictional heat is different from the actual temperature distribution in a rotating brake system. Therefore, the reliability of the cooling effect or thermal stress using the results of these studies is insufficient. In order to overcome these limitations and establish a simulation procedure to predict the frictional heat, this study directly simulates the frictional heat generation by using a thermal-structure coupling element. In this study, we analyzed the thermo-mechanical behavior of a brake model, in order to investigate the thermal characteristics of brake systems by using the Finite Element method (FEM). This study suggests the necessity to directly simulate the frictional heating and it is hoped that it can provide the necessary information for simulations.