• 전기학회논문지
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• 제56권1호
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• pp.174-182
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• 2007

In this paper, we study the influence of infection ratio on gradual reduction of drug dose for the five state HIV infection model that explicitly includes the population of the virus. We first compute all equilibrium points of the model and investigate the stabilities of them. As a result, a bifurcation diagram is obtained which shows a change in the equilibrium points, or in their stability properties, as the drug effect $\eta$ is varied from 0 to 1(alternatively, drug dose is changed from 1 to 0). Based on the bifurcation diagram, we show that the gradual reduction of drug dose can be applied for the treatment of AIDS patients. Moreover, we analyze the influence of the variation of infection ratio on the gradual reduction treatment. Computer simulation results are also presented to validate the proposed results.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1148-1154
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• 2004

The goal of this paper is to verity that the gradual reduction of drug dose (GRDD), which has already been shown by authors to be effective for a simplified HIV infection model, still works for a more realistic model. While the simplified HIV infection model does not take into account an helper-independent CTL, the five state nonlinear model proposed by Wodarz describes the dynamics of both helper-dependent and helper-independent CTL in HIV infection. In this paper, it is shown that, by applying GRDD to Wodarz's five state HIV infection model, the state of HIV infected patient converges to that of non-progressor whose immune response is excited so that his symptom would not be developed into AIDS. Roughly speaking, GRDD is 'slow reduction of dose after the maximum dose for a certain period.' It turns out that an equilibrium representing non-progressor is locally asymptotically stable for the most values of drug dosage, which is required to hold in order to apply GRDD. Simulation results establish that GRDD is still considerably effective both for an AIDS patient and a patient who has been on HAART for a long time.

• 대한소아치과학회지
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• 제31권1호
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• pp.46-51
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• 2004

Talon cusp는 전치부의 치관부에 부가적으로 생성된 교두양 구조물로서 치과이상중 하나이다. Talon cusp는 비심미성, 교합 장애, 치아변위, 발육부의 우식으로 인한 치수 괴사 및 치근단 병변 등을 야기할 수 있다. 그밖에 교모나 치주적인 문제, 혀에의 자극, 그리고 턱관절 동통등의 문제점을 야기할 수 있다. 따라서, Talon cusp의 정확한 조기 진단이 필요하며 각각의 증례에 맞는 처치를 통해 Talon cusp로 인한 문제점을 방지할 수 있다. 본 증례는 각각 영구전치와 유전치에 형성된 Talon cusp로서 이차 상아질을 유도하면서 점차적으로 교두를 삭제하는 치료와 근관 치료를 동반해 교두를 완전 절단하는 치료를 시행하였다.

• 정보처리학회논문지A
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• 제9A권3호
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• pp.379-386
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• 2002

본 논문은 자원제약 조건에서 파이프라인 데이터패스 합성을 위한 스케줄링 방법이며, 우선순위 함수를 사용하여 스케줄할 연산을 선택하는 방법들과는 달리 연산들의 배정가능범위를 점진적으로 축소하여 스케줄한다. 제안방법은 스케줄링 알고리즘과 자원제약 위반을 검출하는 판단알고리즘으로 구성되며, 연산의 배정 가능한 제어단계의 처음 또는 마지막 단계에 임시로 연산을 배정하여 스케줄링 해가 존재하는지를 평가한다. 만약 해를 발견할 수 없다면 이는 자원제약 위반에 의해 연산을 그 제어단계에 배정하는 것이 불가능함을 의미하기 때문에 그 제어단계를 제거하며, 모든 연산에 대하여 배정가능범위 축소가 없을 때까지 이 과정을 반복한다. 벤치마크에 대한 실험결과는 다른 방법들과 비교해서 개선된 스케줄링 결과를 보인다.

• 방송공학회논문지
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• 제18권5호
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• pp.738-748
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• 2013

본 연구는 개인의 불편감을 최소로 유지한 상태에서 3D 자극의 깊이를 늘려나가는 수렴 훈련을 통해 시각적 불편감이 감소되는지를 알아보고자 수행되었다. 실험집단은 수렴 훈련에 사용된 자극의 입체시 깊이가 순차적으로 변화하는지 무선적으로 변화하는지에 따라 두 개의 훈련 집단으로 나뉘었다. 수렴 훈련은 약 2주 간격으로 3회 실시되었으며 훈련 집단의 융합영역(fusional range)을 증가시켰다. 수렴 훈련이 시각적 불편감에 미치는 영향을 평가하기 위해 훈련 회기의 전과 후에 3D 영상을 시청하게 한 뒤, 주관적인 시각적 불편감을 설문 문항으로 측정하였다. 실험 결과, 시각적 불편감은 훈련 자극의 깊이를 순차적으로 변화시킨 훈련집단에서 감소하였다. 이러한 결과는 반복된 수렴 훈련이 3D 환경에서 시각적 불편감을 줄이는 데 효과적일 수 있음을 시사한다.

• 한국농공학회지
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• 제44권1호
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• pp.142-154
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• 2002

This study was performed to investigate constraint effects of deformation (heaving, lateral displacement) of clayey foundation reinforced with sheet pile at the tip of banking on soft ground, under intact state (natural) and the state of vertical drain respectively. The following results are obtained. 1. In view of reduction in heaving or lateral displacement, sheet pile is not supposed to be of use. 2. Sheet pile is effective only when vertical drain is installed for acceleration of consolidation and gradual loading is applied.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1340-1344
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• 1999

The electrochemical behavior of oxide layers on aluminium was studied using electrochemical impedance spectroscopy. Impedance spectra were taken at a compact and a porous oxide layer of Al. The anodic films on Al have a variable stoichiometry with gradual reduction of oxygen deficiency towards the oxide-electrolyte interface. Thus, the interpretation of impedance spectra for oxide layers is complicated, with the impedance of surface layers differing from those of ideal capacitors. This layer behavior with conductance gradients was caused by an inhomogeneous dielectric. The frequency response cannot be described by a single RC element. The oxide layers of Al are properly described by the Young model of dielectric constant with a vertical decay of conductivity.

• 한국전산구조공학회논문집
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• 제19권4호
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• pp.347-356
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• 2006

본 논문에서는 단면상의 화이버 요소를 사용하여 3차원 강구조물의 점진적인 소성화를 고려하는 실용적인 비선형 비탄성 해석방법을 개발하였다. 부재의 p-$\delta$, p-$\Delta$ 등의 기하비선형은 안정함수로 고려하였다. 잔류응력은 단면상에 있는 화이버 요소에 초기응력을 가하여 고려하였다. 각 하중 단계에서 탄성상태인 단면을 계산하여 축강성과 휨강성을 직접 결정함으로서 점진적인 소성화를 고려하였다. 각 화이버 요소의 응력 변화를 계산하여 변형률 반전효과를 고려하였다. 제안된 해석 방법은 3차원 강구조물의 실용적인 해석 및 설계에 유용하게 사용될 것이라 판단한다.

• Design & Manufacturing
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• 제15권4호
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• pp.51-56
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• 2021

Piercing is the process of shearing a circular hole in sheet metal, whose high shear force makes it difficult to secure the durability of tools. In addition, uneven clearance between tools due to poor alignment of the piercing punch causes accelerated die wear and breakage of the tool. This study reviewed the feasibility of in-situ determining alignment failure during the piercing process by analyzing the signal deviation of a bolt-type piezo sensor installed inside the tool whose alignment level was controlled. Finite element analysis was performed to select the optimal sensor location on the piercing tool for sensitive detection of process signals. A well-aligned piercing process results in uniform deformation in the circumferential direction, and shearing is completed at a stroke similar to the sheet thickness. Afterward, a sharp decrease in shear load is observed. The misaligned piecing punch leads to a gradual decrease in the load after the maximum shear load. This gradual decrease is due to the progressive shear deformation that proceeds in the circumferential direction after the initial crack occurs at the narrow clearance site. Therefore, analyzing the stroke at which the maximum shear load occurs and the load reduction rate after that could detect the misalignment of the piercing punch in real-time.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.463-468
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• 1993

The purpose of this study was to evaluate the effects of Vitapex on the periapical lesions. Thirteen single-rooted teeth from ten patients who visited the SNU hospital were endodontically treated with Vitapex and Gutta percha cone, and radiographically and clinically evaluated for a period of 1 to 6 months. The results were as follows : 1. The loss of clinical symtoms was observed in all 13 teeth. 2. The reduction of size of periapical lesions in radiographs was observed in 10 teeth. The periapical lesions of remaining 3 teeth also look better in the radiographs. 3. All 13 teeth showed the reduction of radiolucency. 4. The gradual resorption of Vitapex over the root apex was observed.