• 로봇학회논문지
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• 제19권2호
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• pp.169-175
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• 2024

In this study, we developed control system for stable teleoperation of supermicrosurgical robot platform. The supermicrosurgical robot platform is designed to perform precise anastomosis with micro vessels ranging from 0.3 mm to 0.7 mm. The robotic assistance could help more precise manipulation then manual surgery with the help of motion scaling and tremor filtering. However, since the robotic system could cause several vulnerabilities, control system for stable teleoperation should be preceded. Therefore, we first designed control system including inverse kinematics solver, clutch error interpolator and finite state machine. The inverse kinematics solver was designed to minimized inertial motion of the manipulator and tested by applying orientational motion. To make robot slowly converges to the leader's orientation when orientational error was occurred during clutch, the SLERP was used to interpolate the error. Since synchronized behavior of two manipulators and independent behavior of manipulator both exist, two layered finite state machines were designed. Finally, the control system was evaluated by experiment and showed intended behavior, while maintaining low pose error.

• Journal of Periodontal and Implant Science
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• 제51권6호
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• pp.374-385
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• 2021

Purpose: The aim of this study was to evaluate the effects of locally delivered 1% alendronate (ALN) gel used as an adjunct to non-invasive periodontal therapy. Methods: Ligature-induced periodontitis was performed in 96 rats. The ligature was tied in the cervical area of the mandibular left first molar. The animals were randomly divided into 4 groups: 1) NT, no treatment; 2) SRP, scaling and root planning; 3) SRP/PLA, SRP followed by filling the periodontal pocket with placebo gel (PLA); and 4) SRP/ALN, SRP followed by filling the periodontal pockets with 1% ALN gel. Histomorphometric (percentage of bone in the furcation region [PBF]) and immunohistochemical (receptor activator of nuclear factor-κB ligand, osteoprotegerin, and tartrate-resistant acid phosphatase) analyses were performed. Data were statistically analyzed, with the threshold of statistical significance set at P≤0.05. Results: The SRP, SRP/PLA, and SRP/ALN groups presented a higher PBF than the NT group (P≤0.01) at 7, 15, and 30 days. The SRP/ALN group presented a higher PBF than the SRP/PLA group in all experimental periods, as well as a higher PBF than the SRP group at 15 and 30 days. No differences were observed in the immunohistochemical analyses (P>0.05 for all). Conclusions: Locally delivered 1% ALN gel used as an adjunct to SRP enhanced bone regeneration in the furcation region in a rat model of experimental periodontitis.

• JSTS:Journal of Semiconductor Technology and Science
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• 제8권2호
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• pp.115-120
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• 2008

Carrier velocity in the MOSFET channel is the main driving force for improved transistor performance with scaling. We report measurements of the drift velocity of electrons and holes in silicon inversion layers. A technique for extracting effective carrier velocity which is a more accurate extraction method based on the actual inversion charge measurement is used. This method gives more accurate result over the whole range of $V_{ds}$, because it does not assume a linear approximation to obtain the inversion charge and it does not limit the range of applicable $V_{ds}$. For a very short channel length device, the electron velocity overshoot is observed at room temperature in 37 nm MOSFETs while no hole velocity overshoot is observed down to 36 nm. The electron velocity of short channel device was found to be strongly dependent on the longitudinal field.

• Molecules and Cells
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• 제42권3호
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• pp.237-244
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• 2019

Understanding the mechanisms of cancer drug resistance is a critical challenge in cancer therapy. For many cancer drugs, various resistance mechanisms have been identified such as target alteration, alternative signaling pathways, epithelial-mesenchymal transition, and epigenetic modulation. Resistance may arise via multiple mechanisms even for a single drug, making it necessary to investigate multiple independent models for comprehensive understanding and therapeutic application. In particular, we hypothesize that different resistance processes result in distinct gene expression changes. Here, we present a web-based database, CDRgator (Cancer Drug Resistance navigator) for comparative analysis of gene expression signatures of cancer drug resistance. Resistance signatures were extracted from two different types of datasets. First, resistance signatures were extracted from transcriptomic profiles of cancer cells or patient samples and their resistance-induced counterparts for >30 cancer drugs. Second, drug resistance group signatures were also extracted from two large-scale drug sensitivity datasets representing ~1,000 cancer cell lines. All the datasets are available for download, and are conveniently accessible based on drug class and cancer type, along with analytic features such as clustering analysis, multidimensional scaling, and pathway analysis. CDRgator allows meta-analysis of independent resistance models for more comprehensive understanding of drug-resistance mechanisms that is difficult to accomplish with individual datasets alone (database URL: http://cdrgator.ewha.ac.kr).

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권spc호
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• pp.92-98
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• 2022

Although various methods have been proposed to assess groundwater vulnerability, most of the models merely consider the mobility of contaminants (i.e., intrinsic vulnerability), and the attenuation capacity of vadose zone is often neglected. This study proposed an evaluation model for the attenuation capacity of vadose zone to supplement the limitations of the existing index method models for assessing groundwater vulnerability. The evaluation equation for quantifying the attenuation capacity was developed from the combined linear regression and weighted scaling methods based on the lab-scale experiments using various vadose zone soils having different physical and biogeochemical properties. The proposed semi-quantifying model is expected to effectively assess the attenuation capacity of vadose zone by identifying the main influencing factors as input parameters together with proper weights derived from the coefficients of the regression results. The subsequent scoring and grading system has great versatility while securing the objectivity by effectively incorporating the experimental results.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제24권1호
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• pp.10-16
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• 2018

비용절감을 위해 제한된 서버 워크로드를 통합하는 것은 데이터센터의 효율성에 중요하다. 하지만 더 많은 워크로드가 하나의 서버에 통합되면서, 워크로드들의 성능이 제한된 공유 자원에 대한 경합으로 인해 감소될 수 있다. 이러한 성능감소를 줄이기 위해서 공유자원에 대한 경합을 줄이는 스케줄이 필요하다. 본 논문에서는 이러한 공유자원, 특히 메모리 서브시스템에 대해서 경합을 줄일 수 있는 DVFS(Dynamic Voltage Frequency Scaling) 기반의 메모리 인지 쓰레드 스케줄링 방법을 제안한다. 제안한 알고리즘은 메모리 자원에 대한 경합을 줄이기 위해서, 메모리 자원에 대한 접근을 제한하는 방식으로 두 가지 방법을 사용한다. 메모리 인텐시브 쓰레드를 제한된 코어에서 수행하고, 메모리 인텐시브 쓰레드가 수행되는 코어의 주파수를 낮추어 경합을 완화한다. 제안한 알고리즘을 적용하여 쓰레드 스케줄링 시, 리눅스의 CFS(Completely Fair Scheduler) 대비 최대 43%의 성능향상을 이루고 파워소모를 38% 줄일 수 있었다.

• 한국지능시스템학회논문지
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• 제12권6호
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• pp.511-516
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• 2002

신경회로망은 차원이 확장됨에 따라 학습에 필요한 계산량이 기학급수적으로 증가하는 문제가 발생한다. 이를 극복하기 위해 직교성을 지닌 웨이블릿 신경회로망이 제안되었다. 웨이블릿 함수의 경우 스케일과 중심을 결정함으로써 신경회로망의 노드로 구성된다. 본 논문에서는 웨이블릿 함수를 이용하여 망을 구성하는 과정에 스케일링 함수를 함께 은닉층의 노드로 복합 구성함으로써 스케일링 함수를 이용하여 대강 근사(rough approximation)를 행한 다음, 웨이블릿 함수를 이용하여 미세 근사(fine approximation)를 행하도록 구성하는 복합 신경회로망을 제안한다. 또한, 복합 신경회로망을 구성하는 과정에서 미세 근사에 필요한 웨이블릿 함수의 개수를 유전 알고리즘을 이용하여 결정한다.

• 대한한의학회지
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• 제21권4호
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• pp.204-215
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• 2000

Objectives: This study was conducted to establish the study form of atopic dermatitis in oriental medicine, to find out the effect of herbal medicine and to compare Bangpungtongsungsan group with symptom-complexes prescription group. Methods: We gave scores(1-3) to the 37 outpatients who visited the dept. of Ophthalmotolaryngology & Dermatosurgery of the Kyunghee Oriental Medical Center from June 1,2000 to September 30, 2000. According to transformed the G. Rajka, T. Langeland and Jon M. Hanifin standard. We checked the Eosinophil count, IgE and the scores (intensity: the degree of itching, course: the degree of itching during a year, extent: erythema, lichenification, scaling. dryness, erosion' oozing). After herbal treatment for 6 weeks, we checked the above factors again in the same way. In treatment, we divided the patients into Bangpungtongsungsan group and Symptom-complexes group for cross-comparison. Results: There were 19 patients we could check by score and 14 patients by laboratory. 1. In the 14 lab cases, the number of abnormal value of Eosinophil count and IgE was decreased but it was not significant. 2. In the 19 cases by score, clinical severity of the intensity of itching, lichenification, scaling' dryness was significantly decreased between the before- and after-herbal treatment periods (P<0.01, P<0.01, P<0.05). 3. In 19 cases, clinical severity of erythema, erosion. oozing was decreased after herbal treatment but it was not significant(p>0.05). 4. In point of total score, clinical severity of atopic dermatitis was significantly decreased after herbal treatment(p<0.01). 5. There was no significant difference between Bangpungtongsungsan group and Symptom-complexes group(P<0.05). Conclusions: Although more study is needed, these results indicate that herbal treatment is effective on atopic dermatitis.

• The Korean Journal of Physiology and Pharmacology
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• 제15권6호
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• pp.371-382
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• 2011

We performed experiments using Aplysia neurons to identify the mechanism underlying the changes in the firing patterns in response to temperature changes. When the temperature was gradually increased from $11^{\circ}C$ to $31^{\circ}C$ the firing patterns changed sequentially from the silent state to beating, doublets, beating-chaos, bursting-chaos, square-wave bursting, and bursting-oscillation patterns. When the temperature was decreased over the same temperature range, these sequential changes in the firing patterns reappeared in reverse order. To simulate this entire range of spiking patterns we modified nonlinear differential equations that Chay and Lee made using temperature-dependent scaling factors. To refine the equations, we also analyzed the spike pattern changes in the presence of potassium channel blockers. Based on the solutions of these equations and potassium channel blocker experiments, we found that, as temperature increases, the maximum value of the potassium channel relaxation time constant, ${\tau}_n(t)$ increases, but the maximum value of the probabilities of openings for activation of the potassium channels, n(t) decreases. Accordingly, the voltage-dependent potassium current is likely to play a leading role in the temperature-dependent changes in the firing patterns in Aplysia neurons.

• 방송공학회논문지
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• 제20권6호
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• pp.807-817
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• 2015

본 논문은 고부가가치의 콘텐츠인 디지털 홀로그램을 허락된 사용자만 볼 수 있도록 하는 암호화 방법을 제안한다. 본 논문에서는 프레넬 변환의 특성 즉, 회절거리를 증가시키면 객체영역이 상대적으로 회절평면 일부분에 집중되는 현상을 이용한다. 객체 에너지가 집중되는 영역만을 암호화함으로써 암호화 영역을 크게 줄여 적은 양을 암호화하고도 높은 암호화 효율을 얻는 방법을 제안한다. 그 방법으로는 홀로그램의 복원을 위한 프레넬 변환과 에너지 집중을 위한 프레넬 변환을 통하여 홀로그램 정보를 가운데로 집중시키고 이를 암호화하는 방법이다. 두 번째 프레넬 변환의 파라미터인 회절거리를 조절하여 에너지 집중정도를 결정하고, 가중치를 조절함으로써 암호화 영역의 크기를 조절하여 암호화 강도를 결정한다. 이를 위해 거리와 가중치에 따른 최적의 암호화 지점을 분석한다. 이 암호화 방법을 적용하였을 때 회절거리가 20m일 때 전체 영상의 0.005% ~ 0.02%만 암호화를 하여도 객체정보를 시각적으로 확인할 수 없었다.