• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.194-203
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• 2004

In this paper we propose a Mobile Petri-net Model (MPM) as a new specification model including the QoS parameter that minimizes the transmission delay time. In MPM, we propose a playing time algorithm for supporting the seamless presentation and the smooth playing. The proposed model has a higher guarantee of QoS such as playing time than the previous work.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.2079-2082
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• 2011

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.544-546
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• 2002

최근 무선 통신 기술이 빠르게 발전하면서, 모바일 사용자들의 다양한 서비스에 대한 요청이 증가하고 있다. 그리고 멀티미디어 서비스는 네트웍 효율성의 측면에서 멀티캐스트 전송 기법이 적합하다. 이에, IETF Working Group에서는 이동 컴퓨팅 환경에서 IP 멀티캐스트를 지원하기 위해 Home Subscription 과 Remote Subscription을 제안하였다[1]. 이 방법들은 각각 장.단점을 가지고 있으나, 호스트에게 연속적인 서비스를 제공하지는 못한다. 본 논문에서는 Remote Subscription에서 제공하는 최적의 경로를 사용하면서, 사용자들에게 멀티캐스트 상에서 연속적인 서비스를 제공할 수 있는 방안에 대해 제시한다. Multicast Agent는 자신이 관리하는 네트웍에 현존하는 사용자들의 멀티캐스트 그룹의 관리와 사용자들을 대신하여 그룹에 가입 및 탈퇴를 행한다. 본 논문에서 제시한 방법은 이동 가능한 지역의 Multicast Agent가 미리 멀티캐스트 그룹에 참가함으로써 기존의 제시된 연구 방법들에 비해 사용자들에게 연속적인 서비스를 제공할 수 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.3
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• pp.277-283
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• 2006

A recently proposed method for stabilizing haptic interfaces and teleoperation systems was tested with a 'PHANToM' commercial haptic device. The 'Passivity Observer' (PO) and 'Passivity Control1er' (PC) stabilization method was applied to stabilize the system but also excited a high frequency mode in the device. To solve this problem, we propose a method to use a timevarying desired energy threshold instead of fixed zero energy threshold for the PO, and make the actual energy input follow the timevarying energy threshold. With the time-varying energy threshold, we make the PC control action smooth without sudden impulsive behavior by distributing the dissipation. The proposed new PO/PC approach is applied to PHANToM with high stiffness (K = 5000N/m), and stable and smooth contact is guaranteed. Resetting and active environment display problems also can be solved with the reference energy following idea.

• Bulletin of the Korean Mathematical Society
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• v.48 no.2
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• pp.377-386
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• 2011

For a smooth algebraic curve C of genus g $\geq$ 4, let $SU_C$(r, d) be the moduli space of semistable bundles of rank r $\geq$ 2 over C with fixed determinant of degree d. When (r,d) = 1, it is known that $SU_C$(r, d) is a smooth Fano variety of Picard number 1, whose rational curves passing through a general point have degree $\geq$ r with respect to the ampl generator of Pic($SU_C$(r, d)). In this paper, we study the locus swept out by the rational curves on $SU_C$(r, d) of degree < r. As a by-product, we present another proof of Torelli theorem on $SU_C$(r, d).

• Journal of computational fluids engineering
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• v.9 no.3
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• pp.73-80
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• 2004

A LS(Level Set) formulation is developed for computing two-phase flows on non- orthogonal meshes. Compared with the VOF(Volume-of-Fluid) method based on a non-smooth volume-fraction function, the LS method can calculate an interfacial curvature more accurately by using a smooth distance function. Also, it is quite straightforward to implement for 3-D irregular meshes compared with the VOF method requiring much more complicated geometric calculations. The LS formulation is implemented into a general purpose program for 3-D flows and verified through several test problems.

• Journal of Chest Surgery
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• v.28 no.5
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• pp.521-524
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• 1995

Esophageal leiomyoma is a very rare disease. We present a patient who underwent enucleation of esophageal leiomyoma through a left thoracotomy. The patient was suffered from substernal pain and chest discomfort for 4 months.The esophagogram revealed irregular ovoid smooth filling defect in just proximal portion of G-E junction with the normal mucosal folds. Chest CT demonstrated well-defined, polypoid tumor mass on the anterolateral wall of the distal esophagus. Esophagoscopy revealed normal intact mucosal patterns with swollen hard protruded tumor mass lesion from the just proximal portion of G-E junction. In June, 1993, patient underwent enucleation of esophageal leiomyoma through the left thoracotomy. A horseshoe and spiral shaped, whitish firm tumor mass was noted on the distal esophagus, and the tumor mass was enucleated by blunt dissection carefully. The esophageal leiomyoma was confirmed with histopathological examination. The postoperative course was smooth and uneventful.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.1
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• pp.1-17
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• 1996

There have been considerable researches for solving large-scale separable convex optimization ptoblems. In this paper we present a method for large-scale nonseparable smooth convex optimization problems with block-angular linear constraints. One of them is occurred in reconfiguration of the virtual path network which finds the routing path and assigns the bandwidth of the path for each traffic class in ATM (Asynchronous Transfer Mode) network [1]. The solution is approximated by solving a sequence of the block-angular structured separable quadratic programming problems. Bundle-based decomposition method [10, 11, 12]is applied to each large-scale separable quadratic programming problem. We implement the method and present some computational experiences.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.3
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• pp.173-182
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• 2002

We investigated the effects of operating variables, such as electrical. reactor and gas parameters on toluene removal and discharge property in the dielectric barrier discharge (DBD) process. The toluene removal was initiated with the energy transfer to the reactor by loading of voltages higher than the discharge onset value. The energy transfer and toluene removal increased with the applied voltage. Higher removal rate was observed with smooth surface electrode despite of lower energy transfer compared with the coarse electrode, because more uniform discharge can be obtained on smooth surface state. The decrease of dielectric material thickness enhanced the removal efficiency by increasing the discharge potential. The toluene removal efficiency decreased with the increase of the inlet concentration. The increase of gas retention time enhanced the removal efficiency by the increase of energy density. The oxygen and humidity contents seem to exert significant influences on the toluene removal by dominating the generation of electrons, ions, and radicals which are key factors in the removal mechanism.

• Explosives and Blasting
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• v.20 no.1
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• pp.51-59
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• 2002

터널의 1차 숏크리트 라이닝의 설계선 외측 부분에 발파시 주변에 방사상으로 발생되는 균열들을 제어하기 위하여 Smooth-Blasting 공법 적용하여 외곽공에 정밀폭약(FINEX)을 사용한다. (주)한화에서는 Smooth-Blasting 공법의 중요사항인 폭약선정 사항에서 기존의 G/D 계열의 FINEX를 동일 발파조건에서 여굴 및 미굴의 발생을 최소화시키기 위해 에멀tus 계열의 New FINEX를 개발하여 약종 별로 동일 발파 패턴을 적용하여 터널에서 시험발파를 실시하여 천단 및 좌, 우 측벽의 여굴의 발생범위를 계측장비와, Half Casting을 측정하였다. 현장 시험발파를 통한 결과 흑운모 편마암(일축강도 $1500{\;}Kg/\textrm{cm}^2)$에서 여굴제어는 G/D계열의 FINEX 보다 EMX 계열의 New FINEX가 15~50% 정도 감소가 되었다.