• 제목/요약/키워드: Spatial-temporal combining

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수동형-능동형 위성센서 관측자료를 이용한 대기 에어러솔의 3차원 분포 및 복사강제 효과 산정 (Aerosol Direct Radiative Forcing by Three Dimensional Observations from Passive- and Active- Satellite Sensors)

  • 이권호
    • 한국대기환경학회지
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    • 제28권2호
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    • pp.159-171
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    • 2012
  • Aerosol direct radiative forcing (ADRF) retrieval method was developed by combining data from passive and active satellite sensors. Aerosol optical thickness (AOT) retrieved form the Moderate Resolution Imaging Spectroradiometer (MODIS) as a passive visible sensor and aerosol vertical profile from to the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) as an active laser sensor were investigated an application possibility. Especially, space-born Light Detection and Ranging (Lidar) observation provides a specific knowledge of the optical properties of atmospheric aerosols with spatial, temporal, vertical, and spectral resolutions. On the basis of extensive radiative transfer modeling, it is demonstrated that the use of the aerosol vertical profiles is sensitive to the estimation of ADRF. Throughout the investigation of relationship between aerosol height and ADRF, mean change rates of ADRF per increasing of 1 km aerosol height are smaller at surface than top-of-atmosphere (TOA). As a case study, satellite data for the Asian dust day of March 31, 2007 were used to estimate ADRF. Resulting ADRF values were compared with those retrieved independently from MODIS only data. The absolute difference values are 1.27% at surface level and 4.73% at top of atmosphere (TOA).

MHEG 엔진에서의 멀티미디어 정보 동기 제어기 (Synchronization Controller for Multimedia Object in MHEG Engine)

  • 조성빈;이해원;김진석;박성열
    • 한국정보처리학회논문지
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    • 제3권2호
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    • pp.275-282
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    • 1996
  • 멀티미디어 정보를 상호 교환하고, 작성자가 의도한 대로 프리젠테이션하기 위해 서는 정보의 상호 교환 포멧과 미디어들간의 동기화가 필요하며, 사용자와의 빈번한 상호 동작을 통해 프리젠테이션해야 하는 멀티미디어 응용을 지원하기 위해 서는 이를 지원할 수 있는 기법이 필수적으로 제공되어야 한다. 이를 위해서 본 논 문에서는 국제표준으로 정의된 기능을 수행할 수 있도록 개발된 MHEG엔진에서 조건적, 시간 및 공간적 동기화의 제어와 그리고 멀티미디어 정보를 프티젠테이션하는데 필요한 미디어 데이타들을 결합하여 동기화된 프리젠테이션을 수행할 수 있고, 프리젠테이션 도중에 사용자의 입력을 받아 들여 사용자와 MHEG엔진과의 대화형 처리를 가능하도록 개선된 MHEG엔진에서의 멀티미디어 정보 동기 제어기 및 제어 방법을 제시하였다.

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PHYTOPLANKTON BLOOMING AND OCEANIC CONDITIONS IN THE SEAS AROUND THE SPRATLY ISLANDS

  • Dien, Tran Van;Tang, DanLing;Kawamura, Hiroshi
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.529-532
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    • 2006
  • The oceanic currents in the South China Sea (SCS) are strongly influenced by monsoon winds. A review on the SCS currents has indicated that previous studies have pointed out an anticyclonic circulation in the area between the southern Vietnam coast and the Spratly Islands. However, its detail is not understood because of less information of in situ observations. The physical-biological interaction is quite new research area, which has been established and promoted by means of the ocean color remote sensing. Temporal/spatial variability of the phytoplankton activities are well captured by ocean color (OC) -derived Chlorophyll-a images. Combining the OC-Chl-a and the other high-resolution satellite data (e.g., SST images), the biological aspects of oceanographic variation is well described. The blooming phenomena in the area between the southern Vietnam coast and the Spratly islands are further investigated. Change in the wind-system related to the El Nino generates upwelling/SST-cooling in the sea south of the Spratly Islands through the air-sea-land interaction was studied. The seasonal upwelling is also associated with the harmful algal bloom (HAB) off two side of Indochina Peninsula have investigated. The seasonal variation of SCS phytoplankton blooming and related oceanic conditions in Vietnam coast was observed. Ocean color satellite data has effective contribute to study the oceanic condition and phytoplankton blooming in South China Sea.

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Angiographic PIV 기법을 이용한 혈액유동의 in-vitro 연구 (In vitro application of Angiographic PIV technique to blood flows)

  • 김국배;임남윤;정성용;이상준
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2007년도 추계학술대회
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    • pp.105-108
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    • 2007
  • To diagnose the vascular diseases from the viewpoint of hemodynamics, we need detailed quantitative hemodynamic information of related blood flows with a high spatial resolution of tens micrometer and a high temporal resolution in the order of millisecond. For investigating in-vivo hemodynamic phenomena of vascular circulatory diseases, a new diagnosing technique combining a medical radiography and PIV method was newly developed. This technique called 'Angiographic PIV system' consists of a medical X-ray tube, an X-ray CCD camera, a shutter module for generating double pulse-type X-ray, and a synchronizer. Through several preliminary tests, the feasibility of the Angiographic PIV technique was verified. For in-vivo applications to real blood flows, we developed tracer microcapsules, which were optimized to this system, made of a contrast material of iodine and a matrix material of PVA (polyvinylpyrrolidone). In near future, the Angiographic PIV technique will be used for understanding hemodynamic phenomena of vascular diseases and for their early detection.

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A hybrid method for predicting the dynamic response of free-span submarine pipelines

  • Li, Tongtong;Duan, Menglan;Liang, Wei;An, Chen
    • Ocean Systems Engineering
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    • 제6권4호
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    • pp.363-375
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    • 2016
  • Large numbers of submarine pipelines are laid as the world now is attaching great importance to offshore oil exploitation. Free spanning of submarine pipelines may be caused by seabed unevenness, change of topology, artificial supports, etc. By combining Iwan's wake oscillator model with the differential equation which describes the vibration behavior of free-span submarine pipelines, the pipe-fluid coupling equation is developed and solved in order to study the effect of both internal and external fluid on the vibration behavior of free-span submarine pipelines. Through generalized integral transform technique (GITT), the governing equation describing the transverse displacement is transformed into a system of second-order ordinary differential equations (ODEs) in temporal variable, eliminating the spatial variable. The MATHEMATICA built-in function NDSolve is then used to numerically solve the transformed ODE system. The good convergence of the eigenfunction expansions proved that this method is applicable for predicting the dynamic response of free-span pipelines subjected to both internal flow and external current.

비디오 얼굴 식별 성능개선을 위한 다중 심층합성곱신경망 결합 구조 개발 (Development of Combined Architecture of Multiple Deep Convolutional Neural Networks for Improving Video Face Identification)

  • 김경태;최재영
    • 한국멀티미디어학회논문지
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    • 제22권6호
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    • pp.655-664
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    • 2019
  • In this paper, we propose a novel way of combining multiple deep convolutional neural network (DCNN) architectures which work well for accurate video face identification by adopting a serial combination of 3D and 2D DCNNs. The proposed method first divides an input video sequence (to be recognized) into a number of sub-video sequences. The resulting sub-video sequences are used as input to the 3D DCNN so as to obtain the class-confidence scores for a given input video sequence by considering both temporal and spatial face feature characteristics of input video sequence. The class-confidence scores obtained from corresponding sub-video sequences is combined by forming our proposed class-confidence matrix. The resulting class-confidence matrix is then used as an input for learning 2D DCNN learning which is serially linked to 3D DCNN. Finally, fine-tuned, serially combined DCNN framework is applied for recognizing the identity present in a given test video sequence. To verify the effectiveness of our proposed method, extensive and comparative experiments have been conducted to evaluate our method on COX face databases with their standard face identification protocols. Experimental results showed that our method can achieve better or comparable identification rate compared to other state-of-the-art video FR methods.

A Wide-field-of-view Table-ornament Display Using Electronic Holography

  • Daerak Heo;Hosung Jeon;Sungjin Lim;Joonku Hahn
    • Current Optics and Photonics
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    • 제7권2호
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    • pp.183-190
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    • 2023
  • Three-dimensional (3D) displays provide a significant advantage over traditional 2D displays by offering realistic images, and table-style displays in particular are ideal for generating 3D images that appear to float above a table. These systems are based on multiview displays, and are typically operated using temporal or spatial multiplexing methods to expand the viewing zone (VZ). The VZ is an expanded space that results from merging the sub-viewing zones (SVZs) from which an individual view is made. To increase the viewing angle, many SVZs are usually required. In this paper, we propose a table-ornament electronic holographic display that utilizes 3f parabolic mirrors. In holography, the VZ is not simply expanded but synthesized from SVZs to implement continuous motion parallax. Our proposed system is small enough to be applied as a table ornament, in contrast to traditional tabletop displays that are large and not easily portable. By combining multiview and holographic technologies, our system achieves continuous motion parallax. Specifically, our system projects 340 views using a time-multiplexing method over a range of 240 degrees.

A variational nodal formulation for multi-dimensional unstructured neutron diffusion problems

  • Qizheng Sun ;Wei Xiao;Xiangyue Li ;Han Yin;Tengfei Zhang ;Xiaojing Liu
    • Nuclear Engineering and Technology
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    • 제55권6호
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    • pp.2172-2194
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    • 2023
  • A variational nodal method (VNM) with unstructured-mesh is presented for solving steady-state and dynamic neutron diffusion equations. Orthogonal polynomials are employed for spatial discretization, and the stiffness confinement method (SCM) is implemented for temporal discretization. Coordinate transformation relations are derived to map unstructured triangular nodes to a standard node. Methods for constructing triangular prism space trial functions and identifying unique nodes are elaborated. Additionally, the partitioned matrix (PM) and generalized partitioned matrix (GPM) methods are proposed to accelerate the within-group and power iterations. Neutron diffusion problems with different fuel assembly geometries validate the method. With less than 5 pcm eigenvalue (keff) error and 1% relative power error, the accuracy is comparable to reference methods. In addition, a test case based on the kilowatt heat pipe reactor, KRUSTY, is created, simulated, and evaluated to illustrate the method's precision and geometrical flexibility. The Dodds problem with a step transient perturbation proves that the SCM allows for sufficiently accurate power predictions even with a large time-step of approximately 0.1 s. In addition, combining the PM and GPM results in a speedup ratio of 2-3.

A new surrogate method for the neutron kinetics calculation of nuclear reactor core transients

  • Xiaoqi Li;Youqi Zheng;Xianan Du;Bowen Xiao
    • Nuclear Engineering and Technology
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    • 제56권9호
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    • pp.3571-3584
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    • 2024
  • Reactor core transient calculation is very important for the reactor safety analysis, in which the kernel is neutron kinetics calculation by simulating the variation of neutron density or thermal power over time. Compared with the point kinetics method, the time-space neutron kinetics calculation can provide accurate variation of neutron density in both space and time domain. But it consumes a lot of resources. It is necessary to develop a surrogate model that can quickly obtain the temporal and spatial variation information of neutron density or power with acceptable calculation accuracy. This paper uses the time-varying characteristics of power to construct a time function, parameterizes the time-varying characteristics which contains the information about the spatial change of power. Thereby, the amount of targets to predict in the space domain is compressed. A surrogate method using the machine learning is proposed in this paper. In the construction of a neural network, the input is processed by a convolutional layer, followed by a fully connected layer or a deconvolution layer. For the problem of time sequence disturbance, a structure combining convolutional neural network and recurrent neural network is used. It is verified in the tests of a series of 1D, 2D and 3D reactor models. The predicted values obtained using the constructed neural network models in these tests are in good agreement with the reference values, showing the powerful potential of the surrogate models.

하이브리드 방송 환경 하에서 HTML5 기반 장면구성 기술 (Scene Composition Technology Based on HTML5 in Hybrid Broadcasting Environment)

  • 조민우;박정욱;김규헌
    • 방송공학회논문지
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    • 제18권2호
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    • pp.237-248
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    • 2013
  • 하이브리드 방송(Hybrid Broadcasting) 환경은 다수의 전송경로를 통한 방송 통신 융합 환경이다. 이러한 하이브리드 방송 환경은 기존 방송망의 대역폭 제한으로 소수의 미디어만을 전달하던 것과 달리, 타 통신 전송망을 동시에 활용함으로써 다수의 미디어를 전달할 수 있다. 현재, 스마트TV를 필두로 방송망과 IP망을 결합한 하이브리드 방송 환경이 조성되어 다양한 서비스가 나타나고 있으며, 스마트폰 및 태블릿PC와 같은 타 스마트기기에서 또한 머지않아 하이브리드 방송 환경을 통한 서비스가 나타날 것으로 전망된다. 이렇게 다수의 미디어를 동시에 소비할 수 있는 하이브리드 방송 환경을 효과적으로 활용하는 방법의 하나는 장면구성을 이용하는 것이다. 장면구성은 미디어가 소비되는 시간과 화면상의 공간을 특정함으로써 다수의 미디어를 복합적으로 소비하는 방법이다. 이에 본 논문에서는 하이브리드 방송 환경에 적합하고, 스마트기기에 쉽게 적용될 수 있도록 HTML5를 기반으로 한 장면구성 기술을 제안한다. 하지만 HTML5의 스크립트 언어 및 스타일 언어를 활용한 미디어의 공간구성 및 시간구성은 처리의 복잡성을 높이고, 사용 가능한 단말기의 제한을 줄 수 있다. 또한, 하나의 HTML5 문서는 하나의 장면만 표현할 수 있다. 따라서 제안하는 장면구성 기술은 마크업 언어를 통해 미디어의 공간구성 및 시간구성과 다수 장면을 표현할 수 있도록 HTML5를 확장한다. 더불어 하이브리드 방송환경에 적용을 위한 확장을 포함한다. 이를 위해 HTML5 기술 및 제안하는 장면구성 기술을 소개하고, 구현 및 실험을 통해 본 제안을 검증한다.