• The Journal of Engineering Research
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• v.2 no.1
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• pp.49-56
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• 1997

In emission computed tomography, statistical reconstruction methods in the context of a Bayesian framework have been a topic of interest over the last decade. This was mainly due to the fact that Bayesian approaches can incorporate a priori information into the reconstruction algorithm. Although these approaches can exhibit good performance, their applications to the clinic is hindered mainly by their high computational cost. On the other hand, the speed and simplicity of the filtered backprojection (FBP) algorithm have led to its widespread use in most clinical applications. In this work, we use spline models, which have been quite useful in Bayesian reconstruction, as regularizers for high-frequency apodization in FBP algorithm and show that the effects of using spline models as priors in Bayesian reconstruction can also be achieved in FBP reconstruction.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.1-8
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• 2003

In this paper. we develop an analytical model to evaluate the virtual topology reconfiguration phase of optical Internet networks. To counter the continual approximation problem brought by traditional heuristic approach, we take the traffic prediction into consideration and propose a new heuristic reconfiguration algorithm called Prediction based Multi-stage Reconfiguration approach. We then use this analytical model to study the different configuration operation policies in response to the changing traffic patterns in the higher layer and the congestion level on the virtual topology. This algorithm persists to decide the optimal instant of reconfiguration easily based on the network state. Simulation results show that our virtual topology management Policy significantly outperforms the conventional one, while the required physical resources are limited.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.133-140
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• 2004

Recently, the dental information systems were rapidly developed in order to store and process the data of patients. But, these systems should serve a doctor a good quality information against disease for diagnostic and surgery purpose so as to success in this field. This function of the system it important to persuade patients to undergo proper surgical operation they needed. Hence, 3D teeth model capable of simulating the dental surgery and treatment is necessary Teeth manipulation of dentistry is performed on individual tooth in dental clinic. io, 3D teeth reconstruction system should have the techniques of segmentation and 3D reconstruction adequate for individual tooth. In this paper, we propose the techniques of adaptive optimal segmentation to segment the individual area of tooth, and reconstruction method of tooth based on contour-based method. Each tooth can be segmented from neighboring teeth and alveolar bone in CT images using adaptive optimal threshold computed differently on tooth. Reconstruction of individual tooth using results of segmentation can be manipulated according to user's input and make the simulation of dental surgery and treatment possible.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.490-492
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• 2000

전통적인 컴퓨터 그래픽스분야에서 실제감 있는 장면(scene)을 만들어 내기 위해 표면의 반사특성에 대한 연구가 많이 행해졌다. 표면의 반사특성을 구하기 위하여 기존의 방법들은 복잡한 기하학적 정보를 구하거나 실제 표면의 반사 특성을 얻기 위한 장치를 사용하였다. 본 논문에서는 기하학적 정보 없이 샘플링한 영상으로부터 라디안스맵(radiance map)을 만들고, 이를 이용하여 BRDF를 구하는 방법을 제시한다. 또한 BRDF를 효과적으로 저장하는 방법을 제시한다. 본 논문에서 제시한 방법을 사용하여 임의의 위치에서의 광원에 대하여서 조작이 가능하며 빠른 시간에 새로운 장면을 재구성(reconstruction)할 수 있다. 또한 사용자가 임의로 광원(color light)의 색깔을 변화시킬 수 있고, 여러 개의 광원(multiple light source)에 대하여 장면의 재구성이 가능하다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1997.03a
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• pp.195-207
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• 1997

산업생산 공정의 많은 과정이 종래에는 주로 기술자와 운전자와 조업지식과 경험에 의존하고 있다. 그러나 전산화를 통해서 이러한 기술을 체계적으로 축적할 수 있게 되었지만, 공정상의 모니터링 시스템은 잦은 공정의 변경으로 재구성에는 상당한 노력이 들어간다.물론, 객체 지향언어를 이용하면 좀더 노력을 줄이고 용이하게 할 수는 있다. 그러나, 재 컴파일과 재구성에 시간이 필요이상으로 들어간다. 본 논문은 객체지향기술의 한 형태인 OLE 활용기술 중 OCX를 이용하여 구성요소의 변경측면의 유지 보수에서 상당한 효과서을 확보하였다. 이로 인한 생산 산업에 경쟁력을 확보하도록 산업생산공정의 모니터링 시스템 개발과 구축을 목표로 한다.

• 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.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.549-555
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• 1989

The effect of high temperature aging on the meat tenderness improvement was studied, and also the effect of salt, pyrophosphate and succinic anhydride on binding characteristics of restructed beef were compared. At high temperature aging, shear force value decreased and myofibrillar fragmentation index increased as the aging progressed. From the electronic microscopic observation, the morphological change of myofibril appeared much faster when the meat was aged at high temperature. Added salt increased TBA values and rupture strength while reducing cooking loss. Increase in pyrophosphate decreased rooking loss and Increased rupture strength and TBA value. When salt and pyrophosphate were combined, the effects were somewhat additive. Added succinic anhydride increased cooking loss and hardness and decreased color rating, acceptability rating and adhesiveness, but cohessiveness was not significantly different from control group containing salt and pyrophosphate. The results suggest that high temperature aging have greater improving effect of meat tenderness of Korean native male cattle compared to low temperature aging and addition of succinic ahydride in combination with salt and pyrophosphate reduce binding ability of restructured beef.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.809-814
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• 1991

기존의 CNC Controller를 재구성하면 제어성과 절삭성의 재고에 큰 효과를 낼 수 있다. 현실적으로 시스템의 재구성은, 가) 시스템의 재구성으로 2축 CNC 기계를 다축으로 전환시킬 수 있고, 나) 모터의 직접제어에 의한 G-code 작성과정의 생략이 가능하며, 다) NC 동작의 제어가 소프트웨어로 (C 언어) 이루어 지기 때문에 사용자환경에 맞도록 고객화가 가능한 강점이 있다. 나아가서는 형상의 정의에서 NC 기계동작의 제어 및 온라인 모니터링에 이르는 전과정을 소프트웨어로 일식화 시킬 수 있는 통합 NC 시스템의 구현이 가능하다. 본 논문에서는 이러한 목적으로 연구되고 있는 INCS(Integrated NC System)의 개발현황을 소개한다. INCS는 PC-286, NC Controller, Drive Amplifier, Sensing Device의 하드웨어 시스템과 CAD, CAM 및 CNC 기능을 수행하는 소프트웨어 시스템으로 구성되어 있다. 그래픽 시뮬레이션 및 실제 절삭을 통하여 개발된 방식의 유효성과 효율성을 설명한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.917-919
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• 2008

WDM 네트워크에서 QoS를 향상시키기 위해서는 가상 토폴로지를 효율적으로 재구성할 수 있어야 한다. 본 연구에서는 토폴로지를 재구성할 시점을 결정하고 적절한 파장을 할당하는 기법을 제안함으로써 효과적으로 WDM 네트워크를 운영할 수 있는 WDM 컨트롤러를 제안한다.

• The Journal of Korean Association of Computer Education
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• v.11 no.3
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• pp.43-55
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• 2008

This study investigates how learners extract their implicit knowledge into explicit form of the knowledge. The process of implicit-explicit transfer is known to help learners to reconstruct and refine their knowledge which was constructed before in some ways. Also we investigate which types of explicit form are more effective when it is delivered to other learners. In a classroom-based learning environment, students take educational content that is delivered by instructor and go through the process in which they try to fit the content into their cognitive structure by reconstructing the knowledge into their cognitive model. When they try to deliver their own cognitive model for the knowledge to other learners, they have to transform it into explicit form, and through the process, they reconstruct and refine the cognitive model of the knowledge, and find effective and appropriate way to express it. In this research, we experimented the process on a group of 77 college students and analyzed the results. We also did peer evaluated experiments to see which types of explicit format and factors are more effective than others. The results indicate that the types of explicit form of implicit knowledge play an important role in effectiveness of learning.