• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.721-723
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• 2002

본 논문은 한 장의 사진으로부터 선분과 선분의 중점을 이용한 원시기하모델의 3차원 재구성 시스템을 제안한다. 이 시스템은 선분과 중점을 추출할 수 있는 미리 정의된 다면체를 원시기하모델로 사용하며 그 원시기하모델의 각 점을 사용자가 사진에 매핑 시키는 것으로서 3차원 재구성이 수행된다. 미리 정의된 원시기하모델의 사용은 사용자에게 기존의 소실점 입력 방식보다 직관적인 3차원 재구성을 가능하게 한다. 사진에 매핑된 원시기하모델이 포함하고 있는 2차원상의 선분과 선분의 중점으로부터 원시기하모델을 3차인 재구성한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1709-1712
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• 2005

최근 사용자의 요구가 다양해지는 반면, 기존 운영체제는 정적인 구조를 갖기 때문에 이러한 요구를 효율적으로 반영하기 어렵다. 따라서 운영체제를 동적으로 재구성하여 사용자의 요구를 만족시키는 매커니즘에 관한 연구들이 진행되어 왔다. 그러나 기존의 커널을 재구성하는 기법들은 하드웨어 의존적인 문제점을 가지고 있다. 본 논문에서는 기존 연구들의 문제점을 해결할 수 있는 트랩 기반의 커널 재구성 기법을 제안하고 리눅스 커널에 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.391-393
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• 2003

본 논문은 다양한 환경변화에 적응하는 무선 통신 기술인 SDR시스템에서 소프트웨어 다운로드 과정을 마친 후 소프트웨어 모듈들을 사용자의 요구 또는 환경에 맞게 유연한 재구성을 할 수 있도록 설계하고 재구성 과정에서 발생할 수 있는 다양한 고장이나 결함을 탐지하여 그에 대한 안전한 복구 과정을 통해 전체 시스템의 신뢰성과 가용성을 향상시키는 결함허용 방식의 모듈재구성 메커니즘을 제안한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.29-30
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• 2007

본 논문에서는 배전계통의 정상상태 운용 목적중 하나인 부하의 균등 배분에 관하여 연구하였다. 배전계통의 재구성이라 함은 위의 목적식에 따라 시스템 내에 존재하는 개폐기의 On/Off 상태를 변경하여 구성을 바꾸는 것이다. 이를 통하여 해당 전력계통의 부하가 평준화 되는 것을 보이도록 한다. 또한, 부하의 균등 배분이라는 목적으로 계통을 재구성한 결과와 손실의 최소화를 목적으로 재구성한 결과를 비교하여 보다 효율적인 방법을 제안하고, 그 해가 지역해에 빠지지 않고, 좀 더 빠른 시간에 최적해에 도달할 수 있는 방안을 구현하고자 한다.

• Progress in Medical Physics
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• v.14 no.3
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• pp.167-174
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• 2003

In the radiation treatment planning (RTP) process, especially for stereotactic radiosurgery (SRS), knowing the exact volume and shape and the precise position of a lesion is very important. Sometimes X-ray projection images, such as angiograms, become the best choice for lesion identification. However, while the exact target position can be acquired by bi-projection images, 3D target reconstruction from bi-projection images is considered to be impossible. The aim of this study was to reconstruct the 3D target volume from multiple projection images. It was assumed that we knew the exact target position in advance, and all processes were performed in Target Coordinates, where the origin was the center of the target. We used six projections: two projections were used to make a Reconstruction Box and four projections were for image acquisition. The Reconstruction Box was made up of voxels of 3D matrices. Projection images were transformed into 3D in this virtual box using a geometric back-projection method. The resolution and the accuracy of the reconstructed target volume were dependent on the target size. An algorithm was applied to an ellipsoid model and a horseshoe-shaped model. Projection images were created geometrically using C program language, and reconstruction was also performed using C program language and Matlab ver. 6(The Mathwork Inc., USA). For the ellipsoid model, the reconstructed volume was slightly overestimated, but the target shape and position proved to be correct. For the horseshoe-shaped model, reconstructed volume was somewhat different from the original target model, but there was a considerable improvement in determining the target volume.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.82-92
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• 2008

Recently, many digital signal processing(DSP) applications such as H.264, CDMA and MP3 are predominant tasks for modern high-performance portable devices. These applications are generally computation-intensive, and therefore, require quite complicated accelerator units to improve performance. Designing such specialized, yet fixed DSP accelerators takes lots of effort. Therefore, DSPs with multiple accelerators often have a very poor time-to-market and an unacceptable area overhead. To avoid such long time-to-market and high-area overhead, dynamically reconfigurable DSP architectures have attracted a lot of attention lately. Dynamically reconfigurable DSPs typically employ a multi-functional DSP accelerator which executes similar, yet different multiple kinds of computations for DSP applications. With this type of dynamically reconfigurable DSP accelerators, the time to market reduces significantly. However, integrating multiple functionalities into a single IP often results in excessive control and area overhead. Therefore, delay and power consumption often turn out to be quite excessive. In this thesis, to reduce power consumption of dynamically reconfigurable IPs, we propose a novel fine-grained clock gating scheme, and to reduce size of dynamically reconfigurable IPs, we propose a compact multiplier-less multiplication unit where shifters and adders carry out constant multiplications.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.353-360
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• 2012

Diverse designs of collimator have been applied to Single Photon Emission Computed Tomography (SPECT) according to the purpose of acquisition; thus, it is necessary to reflect geometric characteristic of each collimator for successive image reconstruction. This study carry out reconstruction algorithm for imaging system in nuclear medicine with pinhole collimator. Especially, we study to solve sampling problem which caused in the system model of pinhole collimator. System model for a maximum likelihood expectation maximization (MLEM) was developed based on the geometry of the collimator. The projector and back-projector were separately implemented based on the ray-driven and voxel-driven methods, respectively, to overcome sparse sampling problem. We perform phantom study for pinhole collimator by using geant4 application for tomographic emission(GATE) simulation tool. The reconstructed images show promising results. Designed iterative reconstruction algorithm with unmatched system model effective to remove sampling problem artefact. Proposed algorithm can be used not only for pinhole collimator but also for various collimator system of imaging system in nuclear medicine.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2199-2214
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• 1994

In order to sufficiently utilize the potential effectiveness of ATM networks, systematic and effective network management and control systems must be employed. In addition to network design, planning, and call routing techniques used in traditional circuit-switched networks. ATM networks can provide logical VP(Virtual Path) reconfiguration capabilities which can adapt to changes in the network environment. With a proper application of the VP reconfiguration technique, ATM networks can reduce the overhead of frequent network redesign and the overhead of call routing processing. However, ATM VP reconfiguration is a very complex and difficult problem which consists of many facets of optimization subproblems such as VP routing. VP sizing, VP terminating point location and VC routing. Most previous research on the ATM logical network reconfiguration problem dealt with the subset of the problem. This paper mathematically formulates the ATM network reconfiguration problem completely considering all subproblems. Since it is very difficult to derive the optimal solution of the formulated problem, we develop a heuristic method based on a Max min bandwidth allocation principle. We show the feasibility of the proposed heuristic method with a simple example.

• Journal of Educational Research in Mathematics
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• v.18 no.3
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• pp.309-333
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• 2008

In this research, we reconstructed the textbook on the concept of rate and ratio, which is based on the review on the previous researches and the analysis on the elementary textbook of the 7th mathematics curriculum. We conducted the teaching experiment using the reconstructed textbook, which is to identify the students' conception of rate and ratio and the appropriateness and limit of the reconstructed textbook. As the results of this study, we identify that the changed sequence of instruction (that is, ratio ${\rightarrow}$ percent and value of rate ${\rightarrow}$ rate) was very proper to help students understand the concept of rate and ratio. The relative comparison and absolute comparison and the additive thinking and multiplicative thinking included in the reconstructed textbook were identified very helpful to students' understanding. Meanwhile some contexts given in the reconstructed textbook were identified to cause the students' cognitive confusions.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.10
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• pp.593-602
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• 2004

A new surface reconstruction scheme for approximating the surface from a set of unorganized 3D points is proposed. Our method, called shrink-wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. Proposed method surmounts the genus-0 spherical topology restriction of previous shrink-wrapping based mesh generation technique, and can be applicable to any kind of surface topology. Furthermore, SWBF is much faster than the previous one since it requires only local nearest-point-search in the shrinking process. According to experiments, it is proved to be very robust and efficient for mesh generation from unorganized points cloud.