• 대한기계학회논문집A
• /
• 제21권5호
• /
• pp.819-827
• /
• 1997

In this paper, a new modeling of a fine actuator for an optical pick-up has been proposed and multiobjective optimization of the actuator has been performed. The fine actuator is constituted of the bobbin which is supported by wire suspension, the coils which wind around the bobbin, and the magnets which cause the magnetic flux. If current flows in the coils, magnetic force is so produced as to be balanced with spring force of wire, so the bobbin is pisitioned. In this model the transfer function from input voltage to output displacementof bobbin has been obtained so that we can describe this integrated system with electromagnetic and mechanical parts. Wire suspension is regarded as a continuous Euler beam, damper as distributed viscous damping, and bobbin as a rigid body which can move up- and down- ward motion only. According to the model, the high frequency dynamic characteristics of the fine actuator can be known and the effect of damping can be investigated while the conventional second order model cannot. In multiobjective optimization, two objective functions have been chosen to maximize the fundamental frequency and the sensitivity with respect to the input voltage of the actuator so that Pareto's optimal solutions have been obtained using .epsilon.-constraint method. These objective functions will satisfy the trends which will enhance the access speed and reduce the tracking error in the optical pick-up technology of next generation. In the result of optimization, we obtain the designs of the optical pick-up fine actuator which has high speed, high sensitivity and low resonant peak. Furthermore, we offer the relation between two object functions so that the designer can make easy choice.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권7호
• /
• pp.3305-3310
• /
• 2014

Background: A cancer survivor is defined as anyone who has been diagnosed with cancer, from the time of diagnosis through the rest of their life. The purpose of this study was to examine whether physical functions, health-related outcomes, nutritional status and blood markers in community-dwelling cancer survivors aged 75 years and older are different from those who do not have cancer Materials and Methods: Two hundred seventy-five participants were asked by physicians, nurses, and physical therapists, questions regarding cancer history in a face-to-face interview. Data were collected for demographic information, physical functions, such as handgrip strength, knee extension power, abdominal muscle strength, static standing balance, walking speed and the timed-up-and-go test, health-related outcomes, nutritional status, and blood markers. The measured parameters of survivor diagnosed with cancer were compared with those without a history of cancer. Results: Thirty-seven older adults were previously diagnosed with cancer. Female cancer survivors had lower knee extension power (p<0.05), abdominal muscle strength (p<0.05), walking speed (p<0.05), timed-up-and-go test score (p<0.05), and time to spend on walking per day (p<0.05) than older women without a history of cancer. In men, none of the measured parameters were significantly different between cancer survivors and older men with no history of cancer. Conclusions: The present study shows that partial physical function of women cancer survivors aged 75 years and older differs from that in women with no history of cancer.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제7권1호
• /
• pp.100-114
• /
• 2015

This paper deploys optimization techniques to obtain the optimum hull form of KSUEZMAX at the conditions of full-load draft and design speed. The processes have been carried out using a RaPID-HOP program. The bow and the stern hull-forms are optimized separately without altering neither, and the resulting versions of the two are then combined. Objective functions are the minimum values of wave-making and viscous pressure resistance coefficients for the bow and stern. Parametric modification functions for the bow hull-form variation are SAC shape, section shape (U-V type, DLWL type), bulb shape (bulb height and size); and those for the stern are SAC and section shape (U-V type, DLWL type). WAVIS version 1.3 code is used for the potential and the viscous-flow solver. Prior to the optimization, a parametric study has been conducted to observe the effects of design parameters on the objective functions. SQP has been applied for the optimization algorithm. The model tests have been conducted at a towing tank to evaluate the resistance performance of the optimized hull-form. It has been noted that the optimized hull-form brings 2.4% and 6.8% reduction in total and residual resistance coefficients compared to those of the original hull-form. The propulsive efficiency increases by 2.0% and the delivered power is reduced 3.7%, whereas the propeller rotating speed increases slightly by 0.41 rpm.

• Physical Therapy Rehabilitation Science
• /
• 제13권1호
• /
• pp.43-52
• /
• 2024

Objective: This study aimed to investigate the impact of a 12-week combined cognitive and physical exercise program on cognitive and physical functions in older adults diagnosed with mild cognitive impairment (MCI). Design: A one-group pretest-posttest study. Methods: Twelve participants with MCI engaged in a weekly 60-minute session of combined cognitive and physical exercise program. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA), while physical function was evaluated through measures of muscle strength, postural balance, and walking capabilities. Muscle strength assessments included the arm curl test, handgrip strength, and the 5 sit-to-stand test. Postural balance was evaluated using the one-leg stance test, timed up-and-go test, functional reach test, and four square step test. Walking function was analyzed through a gait analysis device. Pre- and post-intervention measurements were compared to determine the effects of the exercise program. Results: The results demonstrated significant improvements in MoCA, arm curl test, timed up-and-go test, walking speed, and cadence following the 12-week intervention (p<0.05). MoCA scores revealed enhanced cognitive performance, while measures of muscle strength, including the arm curl test, exhibited significant changes. Improvements in timed up-and-go test scores indicated enhanced mobility, accompanied by increased walking speed and cadence, as evidenced by gait analysis. Conclusions: This study suggests that a structured 12-week program incorporating both cognitive and physical exercises can lead to meaningful improvements in cognitive and physical functions among older adults with MCI.

• 한국가스학회지
• /
• 제17권1호
• /
• pp.13-18
• /
• 2013

높이/길이 비가 0.86을 가지는 폭발챔버 내에서 전파하는 화염과 서로 다른 형태의 다중 장애물 사이의 상호작용을 조사하기 위해 폭발실험을 수행하였다. 챔버 내에 장애물 형태는 삼각기둥, 사각기둥 및 원통형으로 변화시켰으며, 장애물의 blockage ratio는 0.43으로 하였다. 전파하는 화염과 장애물 형태에 따른 상호작용을 조사하기 위해 고속카메라를 사용하였으며, 고속카메라로 얻어진 화염 이미지로부터 장애물 주위의 국부 화염속도 및 그 화염속도의 확률밀도함수를 계산하였다. 실험결과, 장애물 형태가 삼각형이었을 때 국부 화염속도가 가장 높게, 원형에서는 가장 낮게 나타났으며, 장애물 후류에서의 국부 화염속도는 장애물 형태에 큰 의존성을 가지는 것으로 나타났다. 또한, 전파하는 화염이 장애물 후류의 미연소가스의 유동과 상호작용할 때 국부 화염속도의 확률밀도함수는 화염속도가 높은 방향으로 광범위하게 분포되는 것으로 나타났다.

• 디지털융복합연구
• /
• 제12권6호
• /
• pp.231-236
• /
• 2014

본 논문은 호스트(PC) 기반의 직렬처리 방식으로 도로영역 추출 방식에 디바이스(Graphic Card) 기반의 병렬 처리 방식을 추가함으로써 보다 향상된 처리 속도를 가지는 도로영역검출을 제안하였다. OpenCV CUDA는 기존의 OpenCV와 CUDA를 연동하여 병렬 처리 방식의 많은 함수들을 지원한다. 또한 OpenCV와 CUDA 연동 시 환경 설정이 완료된 OpenCV CUDA 함수들은 사용자의 디바이스(Graphic Card) 사양에 최적화된다. 따라서 OpenCV CUDA 사용은 알고리즘 검증 및 시뮬레이션 결과 도출의 용이성을 제공한다. 제안된 방법은 OpenCV CUDA 와 NVIDIA GeForce GTX 560 Ti 모델의 그래픽 카드를 사용하여 기존 방식보다 3.09배 빠른 처리 속도를 가짐을 실험을 통해 검증한다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2006년도 춘계종합학술대회
• /
• pp.522-525
• /
• 2006

최근 모바일 기기들은 3D 게임, 무선 인터넷, 동영상, DMB, GPS, PMP 등의 기능을 추가하고 있으며 이들을 제대로 지원하기 위해 디스플레이의 크기도 점차 커지고 있다. 이에 따라 프로세서에서 디스플레이 장치로의 더 빠른 전송 속도에 대한 요구도 커지고 있으나 기존의 병렬 방식의 인터페이스로는 그 한계에 이르렀다. 이러한 한계를 극복하기 위해 최근에 고속 직렬 방식의 인터페이스가 대두되고 있다. 직렬 방식의 장점은 높은 대역폭과 더불어 적은 신호선 수, 저전력 특성, 전자파 장애의 최소화라는 특징을 지닌다. 본 논문에서는 고속 직렬 방식의 물리적 계층으로 LVDS(Low-Voltage Differential Signaling)를 응용하고 링크 계층으로 패킷 방식을 사용하는 인터페이스를 구현하여 이를 디스플레이 장치에 적용한다. 구현된 직렬 인터페이스는 충분한 전송 대역폭과 함께 대폭 감소된 신호선 개수라는 특징을 갖는다.

• 응용통계연구
• /
• 제22권6호
• /
• pp.1177-1190
• /
• 2009

도로의 성능을 측정는데 있어서, 주행속도는 가장 중요한 정보가 된다. 또한 도로 교통의 정보를 제공하는데 있어서 현 시점의 교통정보와 더불어 향후 예측되는 교통정보를 함께 제공하는 것은 보다 정확한 예측 시간과 구간을 제공하기 위한 차별화된 기능이라 할 수 있다. 본 연구에서는 그 동안 축적된 도로 구간별 속도 자료를 이용하여 속도 패턴을 다양하게 분석하고 퓨리에 변환 및 삼각함수를 설명변수로 하는 시계열 회귀모형을 이용한 예측모형을 개발하여 구간별 및 시간대별 평균 속도를 예측하였다. 이와 더불어 보다 정확한 예측을 위하여 결측치에 대한 대체 방법 및 특이치 처리 방법을 함께 고려하였고 방대한 데이터에 대한 효율적인 분석을 위하여 유사 속도 구간에 대한 그룹핑(grouping) 방법도 제안하였다.

• 생물정신의학
• /
• 제9권2호
• /
• pp.103-111
• /
• 2002

Neurocognitive research focusing on cognitive deficits in Depression has resulted in several important but yet potentially contradictory findings. Much literature documents the presence of significant neurocognitive impairments in depressive patients. Studies have shown that dysthymic disorder patients demonstrate a diffuse pattern of cognitive impairment which is frequently indistinguishable from that of focal braindamaged patients. Some reports have suggested that there is a focal pattern of deficit, such as anterior cingulate dysfunction, frontal lobe impairment, or dysfunction of the temporal-limbic cortex. The aim of this study is to evaluate the neurocognitive functions in dysthymic disorder patients, and to compare the functions with those of major depressive disorder patients. The subjects are 17 dysthymic disorder patients. And their neurocognitive functions are compared with those of 23 major depressive episode patients. Patients with a history of neurologic disease, alcohol dependence, substance abuse and mental retardation are excluded. They are assessed with a part of Vienna Test System which is computerized neurocognitive function tests and can evaluate attention, eductive ability, reproductive ability, visuoperceptual analysis, vigilance, visual immediate memory, the speed of information-processing, judgement, and fine motor coordinations. There are no other specific difference between two groups, except the result of cognitrone test. This study provides information about the neurocognitive functions and some difference between major depressive disorder patients and carefully diagnosed dysthymic disorder patients.

• 대한통합의학회지
• /
• 제8권4호
• /
• pp.143-154
• /
• 2020

Purpose : This study aims to investigate the effect of instrument-activities daily living training through client-centered home visitation on the cognitive functions, occupational performance, and instrument-activities daily living of elderly at the cognitive support grade(Grade6). Methods : The subject of this study was a 66-year-old woman living in G Metropolitan City, who has been diagnosed with Alzheimer's and mild dementia. The study period was from March 17, 2020 through June 12, 2020, and the A-B-A' design, among the individual case experiments, was adopted as the study design. For the data analysis, descriptive statistic and visual analysis using graph were used for the change of cognitive functions, occupational performance, and instrument-activities daily living. Results : The instrument-activities daily living provided through client-centered home visitation improved the subject's cognitive functions, occupational performance(performance, satisfaction) and instrument-activities daily living. Conclusion : This study showed that daily life training through client-centered home visitation can help elderly people at the cognitive support grade select for themselves the problems of daily life caused by cognitive decline and practice specific action plans, thereby enabling them to maintain and improve the cognitive functions necessary for the performance of activities, such as comprehension, memory, and thinking skills. In addition, it is thought that the activities based on the subject's preferences, performance, and sense of importance assured the subject of feelings of motivation and the possibility of participation, and had a positive effect on the subject's performance speed and rate. With the above in mind, Instrument-activities daily living client-centered home visitation is proposed as a potential practical intervention program for individuals. It can help elderly people at cognitive support grade to maintain and improve their functions, thereby delaying the progress of their condition to severe dementia.