• 대한토목학회논문집
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• 제12권4_1호
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• pp.137-150
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• 1992

가변흘수(可變吃水)를 갖는 힌지형(型) 조파기(造波機)에 의한 조파현상(造波現像)을 다룬 2차해(次解)가 제시(提示)되었다. 피스톤형(型) 조파기(造波機)의 경우도 무한흘수(無限吃水)를 갖는 힌지형(型) 조파기(造波機)의 경우로서 함께 취급되었다. 2차해는 평면조파판(平面造波板)에 의해 생성(生成)되는 파(波)가 서로 다른 파속(波速)을 갖는 스토우크스 2차파(次波)와 2차자유진행파(次自由進行波)로 구성(構成)됨을 보여준다. 2차(次) 자유진행파(自由進行波)의 진폭(振幅)은 천해영역(淺海領域)에서 상대적으로 크고, 심해영역(深海領域)에서는 스토우크파(波) 진폭(振幅)의 10% 이내로 감소(減少)한다. 깊은 흘수(吃水)를 갖는 (수로(水路)바닥 가까이 힌지점(点)에 있는) 조파기(造波機)일수록 천해(淺海)와 중간수심(中間水深) 영역(領域)에서 진폭(振幅)이 작은 자유진행파(自由進行波)를 생성(生成)하나, 심해역(深海域)에서는 그와 반대의 현상(現像)을 보인다.

• 한국멀티미디어학회논문지
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• 제13권10호
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• pp.1547-1556
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• 2010

현재까지 유아나 장애인을 위한 컴퓨터 활용 교육 콘텐츠는 지각훈련, 인지훈련, 한글 교육 등 다양한 분야에서 개발되었으나 가장 큰 문제점은 컴퓨터 모니터 앞에서 장시간 마우스를 이용하여 교육을 할 경우 활동성이 저하된다는 점이다. 이것은 특히 왕성하게 운동 능력이 발달하는 시기의 유아와 운동 장애로 인해 활동 기회가 부족한 장애 아동에게 적잖은 문제점으로 지적되어 왔다. 이와 같은 문제점을 개선하고 활동성과 협동력, 몰입성을 강화시키는 콘텐츠를 개발하기 위해서는 터치스크린과 같은 스크린 상에서 인간의 동작을 인식하여 이를 대화식으로 보여주는 기술이 필요하다 본 연구에서는 기존의 컴퓨터 활용 콘텐츠의 단점을 보완하고, 사용자의 활동성을 강화하기 위해 위모트가 가지는 센서 기술을 활용하여 실시간으로 빔 프로젝터나 컴퓨터 스크린으로 교육콘텐츠를 제공하고 신체를 직접 움직이며 적외선 펜을 사용하여 자극에 반응하는 교육 콘텐츠를 개발하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.499-500
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• 2006

The electrode wear in micro-EDM significantly deteriorates the machining accuracy. In this regard, electrode wear needs to be compensated in-process to improve the product quality. Therefore, there are substantial amount of research about electrode wear. In this study a control method for micro-EDM using discharge pulse counting is proposed. The method is based on the assumption that the removed workpiece volume is proportional to the number of discharge pulses, which is verified from experimental results analyzing geometrically machined volume according to various number of discharges. Especially, the method has an advantage that electrode wear does not need to be concerned. The proposed method is implemented to an actual micro-EDM system using high speed data acquisition board, simple counting algorithm with 3 axis motion system. As a result, it is demonstrated that the volume of hole machined by EDM drilling can be accurately estimated using the number of discharge pulses. In EDM milling process a micro groove without depth variation caused by electrode wear could be machined using the developed control method. Consequently, it is shown that machining accuracy in drilling and milling processes can be improved by using process control based on the number of discharge pulses.

• 한국전문물리치료학회지
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• 제24권1호
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• pp.30-40
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• 2017

Background: Many studies have reported positive results of the various mirror training and virtual reality games in improving dynamic standing balance and posture adjustment in chronic stroke patients. However, no systematic study has been conducted to compare the effects of virtual reality games and the mirror balance training. Objects: The purpose of this study was to compare the effectiveness of Wii balance games and Mirror Self-Balancing Exercises in improving proprioception of knee joint and standing balance of people with chronic stroke. Methods: Twenty patients with chronic stroke volunteered for this study. The subjects were randomly divided into a Wii balance games group and a Mirror Self-Balancing Exercises group with 10 patients in each group. Each training was performed for 30 mins a day for 4 days. In addition to the balance training, 30 mins neuro-developmental-treatment based routine physical therapy was given to both groups. Proprioception was measured using two continuous passive motion devices, and static balance was measured using a Wii balance board. Dynamic balance assessment tools included the Berg Balance Scale, Dynamic Gait Index, and Timed Up-and-Go test. Results: All measured variables before and after the experimental results showed a significant improvement in both groups (p<.05). Only the improvement of the affected knee proprioception appeared to be significantly greater in the Wii balance game group (p<.05). However, other variables did not differ between the groups (p>.05). Conclusion: The findings suggest that both Wii balance games and Mirror Self-Balancing Exercises may be helpful for improving the proprioception of knee joint and the balance of patients with chronic stroke.

• 한국전문물리치료학회지
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• 제13권4호
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• pp.23-29
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• 2006

The purpose of the present study was to examine gaze effects on spatial and kinematic characteristics during a pointing task. Subjects were asked to watch and point to an aimed target (2 mm in diameter) displayed on a vertically mounted board. Four gaze conditions were developed as combinations of "seeing-aiming" in terms of the eye movements: Focal-Focal (F-F), Focal-Fixing (F-X), Fixing-Focal (X-F), and Fixing-Fixing (X-X). Both the home target and an aimed target were presented for 1 second and then were disappeared in F-F and X-F. In X-F and X-X, only an aimed target disappeared after 1 second. Subjects were asked to point (with index finger tip) to an aimed target accurately as soon as the aimed target was removed. A significant main effect of gaze was found (p<.01) for normalized movement time. Peripheral retina targets had significantly larger absolute error compared to central retina targets on the x (medio-lateral) and z (superior-inferior) axes (p<.01). A significant undershooting to peripheral retina targets on the x axis was found (p<.01). F-F and X-F had larger peak velocities compared to F-X and X-X (p<.01). F-F and X-F were characterized by more time spent in the deceleration phase compared to F-X and X-X (p<.01). The present study demonstrates that central vision utilizes a form of on-line visual processing to reach to an object, and thus increases spatial accuracy. However, peripheral vision utilizes a relatively off-line visual processing with a dependency on proprioceptive information.

• 한국의류산업학회지
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• 제8권1호
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• pp.99-106
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• 2006

With the growing interest in pet dogs and pet dog's wear I used this study to compare and analyze the pattern used by each supplier and developed a new pattern for pet dogs' wear which is appropriate for pet dogs' body lines and movement. Test subjects were 91 pet dogs in Busan and after comparing 3 patterns from different suppliers, I developed the pattern reflecting pet dogs' body shapes and movement. Results are as follows; 1) As a result of analyzing measurements, it was found that pet dogs motion in walking on four feet, is different from that of people on two feet. For center measurements, their waist to bust length is longer than their waist to back length. The result of analysis shows that bust circumference impacts most other measurement results and it seems that better results are achieved if the bust line is taken into consideration when measuring bust back length, bust front length, neck base circumference, front leg arc, the length between lateral shoulder etc. 2) As a result of comparing suppliers' patterns, it was discovered that each supplier has different sizes for the same patterns and those sizes are not standardized across the board. Even if the same size of pattern was actually used in the production of pet dogs' wear by the individual companies, there were many variations in size for each item. 3) To develop a more standard pattern of pet dogs' wear, I collected and analyzed 3 patterns from each supplier and designed a new pattern, revising it three times. After test-wearing of the experimental pattern and the studied patterns, and comparing and analyzing the results, the studied pattern had similarly better estimation than the experimental one.

• 척추신경추나의학회지
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• 제9권1호
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• pp.55-65
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• 2014

Objectives : The purpose of this review is to investigate the trends of traditional korean medicine treatments on frozen shoulder. Methods : We investigated the studies on traditional korean medicine treatments for frozen shoulder via searching 6 Korean web databases. As a result, 32 research papers were found to be analyzed according to their published year, the titles of journals, published institution, the types of study, the number of cases, the types of treatments, the instruments for assessment and ethical approvals. Results : 32 papers were published since 1989. The studies on traditional korean medicine treatments about frozen shoulder were mainly published in The journal of korean acupuncture & moxibustion medicine. 10 case series, 7 reviews, 6 non-randomized controlled trials, 5 randomized controlled trials and 4 case reports had been under research. In most of the research, the number of the cases were not enough. In 15 cases of the studies, various traditional korean medicine treatments were used to treat the symptoms. In 8 cases of the studies, one method was used to treat the symptoms. Range of motion(ROM) and visual analogue scale(VAS) were used as primary assessments. Among the 25 clinical studies, 5 of them were accepted by institutional review board(IRB). Conclusion : In this study, we analyzed the trends of traditional korean medicine treatments on frozen shoulder. Reviewing the domestic trends of studies on traditional korean medicine treatments for frozen shoulder and examining the strong and weak points of those treatments are essential for the future studies.

• 한국항해항만학회지
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• 제38권5호
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• pp.479-484
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• 2014

본 연구에서는 승선 중인 해기사의 피로도 유발요인에 대한 현황과 개인별 피로도 자각증상 항목들에 대한 실태를 파악하기 위하여 설문조사를 실시하고 그 결과를 선종별로 분석하였다. 설문조사 분석결과 선종별로 많은 해기사들이 수면과 휴식시간의 부족을 겪고 있음을 확인할 수 있었고, 수면을 방해하는 요인은 다양하지만 특히 날씨, 선체의 운동 및 진동, 소음, 거주시설 등 환경적 요인이 많이 작용하는 것을 파악하였다. 그리고 일부 선종의 경우는 하루 평균 10시간 이상 당직근무를 수행하고 있었으며, 과다한 업무로 기인한 스트레스와 더불어 많은 피로감을 느끼는 것으로 조사되었고, 영역별(육체적, 정신적, 감정적) 피로도 증상 측정항목에 대해서 일부항목의 경우는 많은 해기사들이 상당한 피로도 증상을 경험하고 있는 것으로 분석되었다.

• 대한원격탐사학회지
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• 제18권1호
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• pp.53-59
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• 2002

The MSC is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a GSD(Ground Sample Distance) of 1 m over the entire FOV(Field Of View) at altitude 685 km. The instrument is designed to haute an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data compression/storage. The MSC instrument has one channel for panchromatic imaging and four channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI(Time Belayed Integration) CCD(Charge Coupled Device) FPA(Focal Plane Assembly). The MSC hardware consists of three subsystem, EOS(Electro Optic camera Subsystem), PMU(Payload Management Unit) and PDTS(Payload Data Transmission Subsystem) and each subsystems are currently under development and will be integrated and verified through functional and space environment tests. Final verified MSC will be delivered to spacecraft bus for AIT(Assembly, Integration and Test) and then COMSAT-2 satellite will be launched after verification process through IST(Integrated Satellite Test). In this paper, the introduction of MSC, the configuration of MSC electronics including electrical interlace and design of CEU(Camera Electronic Unit) in EOS are described. MSC Operation parameters induced from the operation concept are discussed and analyzed to find the influence of system for on-orbit operation in future.

• Coupled systems mechanics
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• 제4권4호
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• pp.279-295
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• 2015

The article presents a theoretical-experimental approach developed for modeling the coefficient of sliding friction in the dynamic system tool-workpiece in slide diamond burnishing of low-alloy unhardened steels. The experimental setup, implemented on conventional lathe, includes a specially designed device, with a straight cantilever beam as body. The beam is simultaneously loaded by bending (from transverse slide friction force) and compression (from longitudinal burnishing force), which is a reason for geometrical nonlinearity. A method, based on the idea of separation of the variables (time and metric) before establishing the differential equation of motion, has been applied for dynamic modeling of the beam elastic curve. Between the longitudinal (burnishing force) and transverse (slide friction force) forces exists a correlation defined by Coulomb's law of sliding friction. On this basis, an analytical relationship between the beam deflection and the sought friction coefficient has been obtained. In order to measure the deflection of the beam, strain gauges connected in a "full bridge" type of circuit are used. A flexible adhesive is selected, which provides an opportunity for dynamic measurements through the constructed measuring system. The signal is proportional to the beam deflection and is fed to the analog input of USB DAQ board, from where the signal enters in a purposely created virtual instrument which is developed by means of Labview. The basic characteristic of the virtual instrument is the ability to record and visualize in a real time the measured deflection. The signal sampling frequency is chosen in accordance with Nyquist-Shannon sampling theorem. In order to obtain a regression model of the friction coefficient with the participation of the diamond burnishing process parameters, an experimental design with 55 experimental points is synthesized. A regression analysis and analysis of variance have been carried out. The influence of the factors on the friction coefficient is established using sections of the hyper-surface of the friction coefficient model with the hyper-planes.