• Earthquakes and Structures
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• 제7권6호
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• pp.895-908
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• 2014

The main objective of critical excitation methods is to reveal the worst possible response of structures. This goal is accomplished by considering the uncertainties of ground motion, which is subjected to the appropriate constraints, such as earthquake power and intensity limit. The concentration of this current study is on the theoretical optimization aspect, as is the case with the majority of conventional critical excitation methods. However, these previous studies on critical excitation lead to a discontinuous power spectral density (PSD). This paper introduces some critical excitations which contain proper continuity in frequency domain. The main idea for generating such continuous excitations stems from the combination of two continuous functions. On the other hand, in order to provide a non-stationary model, this paper attempts to present an appropriate envelope function, which unlike the previous envelope functions, can properly cover the natural earthquakes' accelerograms based on multi-peak conditions. Finally, the proposed method is developed into the multiple-degree-of-freedom (M.D.O.F) structures.

• 한국CDE학회논문집
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• 제16권4호
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• pp.277-284
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• 2011

In tangible augmented reality (AR) environments for virtual prototyping, the user interacts with virtual products by manipulating tangible objects with his or her hands, but the user often encounter awkward situations in which his or her hands are occluded by augmented virtual objects, which reduces both immersion and ease of interaction. In this paper, we present how to resolve such hand region occlusion in order to enhance natural interaction and immersive visualization. In the AR environment considered, we use two types (product-type and pointer-type) of tangible objects for tangible user interaction with a virtual product of interest. Holding the tangible objects with his or her hands, the user can create input events by touching specified regions of the product-type tangible object with the pointer-type tangible object. We developed a method for resolving hand region occlusion frequently arising during such user interaction, It first detect hand region in a real image and refines the rendered image of the virtual object by subtracting the hand region from the rendered image, Then, it superimposes the refined image onto the real image to obtain an image in which the occlusion is resolved. Incorporated into tangible AR interaction for virtual prototyping of handheld products such as cellular phones and MP3 players, the method has been found by a preliminary user study that it is not only useful to improve natural interaction and immersive visualization of virtual products, but also helpful for making the users experience the products' shapes and functions better.

• 전기학회논문지
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• 제56권1호
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• pp.214-221
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• 2007

This paper presents a myoelectric hand prosthesis(MHP) with two degree of freedom(2-DOF), which consists of a mechanical hand, a surface myoelectric sensor(SMES) for measuring myoelectric signal, a control system and a charging battery. The actuation for the 2-DOF hand functions such as grasping and wrist rotation was performed by two DC-motors, and controlled by myoelectric signal measured from the residual forearm muscle. The grip force of the MHP was automatically changed by a mechanical automatic speed reducer mounted on the hand. The skin interface of SMES was composed of the electrodes using the SUS440 metal in order to endure a wet condition due to the sweat. The sensor was embedded with a amplifier and a filter circuit for rejecting the offset voltage caused by power line noises. The control system was composed of the grip force sensor, the slip sensor, and the two controllers. The two controllers were made of a RISC-type microprocessor, and its software was executed on a real-time kernel. The control system used Force Sensing Resistors, FSR, as slip pick-ups at the fingertip of a thumb and the grip force information was obtained from a strain-gauge on the lever of the MHP. The experimental results were showed that the proposed control system is feasible for the MHP.

• 대한인간공학회지
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• 제31권4호
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• pp.533-540
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• 2012

Objective: This paper targets a framework of a hand gesture based interface design. Background: While a modeling of contact-based interfaces has focused on users' ergonomic interface designs and real-time technologies, an implementation of a contactless interface needs error-free classifications as an essential prior condition. These trends made many research studies concentrate on the designs of feature vectors, learning models and their tests. Even though there have been remarkable advances in this field, the ignorance of ergonomics and users' cognitions result in several problems including a user's uneasy behaviors. Method: In order to incorporate compatibilities considering users' comfortable behaviors and device's classification abilities simultaneously, classification-oriented gestures are extracted using the suggested human-hand model and closed-loop classification procedures. Out of the extracted gestures, the compatibility-oriented gestures are acquired though human's ergonomic and cognitive experiments. Then, the obtained hand gestures are converted into a series of hand behaviors - Handycon - which is mapped into several functions in a mobile device. Results: This Handycon model guarantees users' easy behavior and helps fast understandings as well as the high classification rate. Conclusion and Application: The suggested framework contributes to develop a hand gesture-based contactless interface model considering compatibilities between human and device. The suggested procedures can be applied effectively into other contactless interface designs.

• 대한통합의학회지
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• 제7권2호
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• pp.69-76
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• 2019

Purpose : This study examined the effects of a virtual reality rehabilitation program on stroke patients' upper extremity functions and activities of daily living (ADL). Methods : The subjects were equally and randomly divided into an experimental group (n=16) to whom a virtual reality rehabilitation program was applied and a control group (n=16) who received traditional occupational therapy. The intervention was applied five times per week, 30 minutes per each time, for six weeks. Jebsen-Taylor hand function test was conducted and the subjects' Manual Function Test was measured to examine their upper extremity functions before and after the treatment intervention, and a Korean version of modified Barthel index was calculated to look at their activities of daily living. Results : After the intervention, the upper extremity functions and activities of daily living of the participants in both groups significantly improved (p<.05). However, the improvements in these parameters among the participants in the virtual reality rehabilitation program were significantly greater than those in the control group (p>.05). Conclusion : The virtual reality rehabilitation program is a stable and reliable intervention method for enhancing the upper limb functions and activities of daily living of stroke patients.

• 정보보호학회논문지
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• 제19권2호
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• pp.23-30
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• 2009

회전대칭 불함수는 고속계산에 유리하고 암호학적으로 우수한 성질을 나타내어 최근 많은 주목을 받고 있다. 예를 들어, 부호이론에서 중요한 문제가 회전대칭 불함수를 이용하여 해결된 사례가 있고, 고속 해시함수 설계에 응용된 경우도 있다. 다른 한편으로, 매우 단순한 형태의 회전대칭 이차 불함수에 대한 비선형성 및 해명무게의 정확한 공식이 발견되었으며[2,8], 더 넓은 범위의 함수들에 대한 보다 일반적인 공식들도 발견되었다[6]. 본 논문에서는 이들 공식들을 조금 더 확장하여 일차항들이 포함된 회전대칭 이차 불함수에 대한 정확한 해밍무게 공식을 유도한다.

• 한국콘텐츠학회논문지
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• 제17권3호
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• pp.74-87
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• 2017

본 연구는 아직 제품으로 등장하지 않은 플렉시블 디스플레이 기반의 소형 원통형 디스플레이를 위한 사용자 정의 기반의 핸드 제스처 도출을 목표로 한다. 이를 위하여 먼저 소형 원통형 디스플레이의 크기와 기능을 정의하고, 해당 기능 수행을 위한 태스크를 도출하였다. 이후 가상의 원통형 디스플레이 인터페이스와 이를 조작하기 위한 물리적 오브젝트를 각각 구현하여 사용자들이 실제 원통형 디스플레이를 조작하는 것과 유사한 환경을 제작하였고, 제스처 도출을 위한 태스크를 수행했을 경우 발생하는 결과를 가상의 원통형 디스플레이에 제시하여 사용자들이 해당 조작에 적합하다고 판단되는 제스처를 정의할 수 있도록 하였다. 도출된 각 태스크 별 제스처 그룹에서 빈도수를 토대로 대표 제스처를 선정하였으며, 각 제스처에 대한 의견 일치 점수를 도출하였다. 마지막으로 제스처 분석 및 사용자 인터뷰를 기반으로 제스처 도출에 활용되는 멘탈 모델을 관찰 하였다.

• Archives of Plastic Surgery
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• 제42권5호
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• pp.614-618
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• 2015

Background Hand strength deficit following digital replantation is usually attributed to the mechanical deficiency of the replanted digit. Zone 1 replantation, however, should not be associated with any mechanical deficit, as the joint and tendon are intact. We evaluate shortterm motor functions in patients who have undergone single-digit zone 1 replantation. Methods A single-institution retrospective review was performed for all patients who underwent zone 1 replantation. Hand and pinch strengths were evaluated using standard dynamometers. Each set of measurements was pooled according to follow-up periods (within 1 month, 1 to 2 months, 2 to 3 months, and after 3 months). The uninjured hand was used as reference for measurements. Results The review identified 53 patients who had undergone zone 1 replantation and presented for follow-up visits. Compared to the uninjured hand, dynamometer measurements revealed significantly less strength for the hand with replanted digit at one month. The relative mean grip, pulp, and key pinch strength were 31%, 46%, and 48% of the uninjured hand. These three strength measurements gradually increased, with relative strength measurements of 59%, 70%, and 78% for 4-month follow up. Conclusions Despite the lack of joint or tendon injury, strength of the injured hand was significantly lower than that of the uninjured hand during the 4 months following replantation. Improved rehabilitation strategies are needed to diminish the short-term negative impact that an isolated zone 1 replantation has on the overall hand strength.

• 동의생리병리학회지
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• 제25권2호
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• pp.365-372
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• 2011

The purpose of this study was to identify the effects of aroma hand massage and hand massage on sleep disturbance and depression in hospitalized elderly patients. The study was performed using a nonequivalent control group pretest-posttest design. The data was collected by using questionnaires and the measured values from 1 June to 31 August, 2006. The subjects who were admitted to the B Medical Center Hospital in Busan. A total of 40 subjects were selected : 20 in the experimental group and 20 in the control group. The aroma hand massage was administered to the experimental group, and hand massage was given to the control group. The experimental group were applied the aroma hand massage executed by methods such as effleurage, circling, pressing, etc. to both hands using a solution diluting six drops of lavender oil, and bergamot oil, 3% in jojoba oil 20 cc. In the experimental group, aroma hand massage was given for 10 minutes, three times a week, during 2 weeks. The control group receiving the hand massage was given the massage for 10 minutes every two days for 2 weeks. The result of the study are as follows : 1) The first hypothesis : "The Experimental group would have a higher degree of sleep score than the control group" was supported(F=31.798, p=p<0.001). 2) The second hypothesis : "The Experimental group would have a lower degree of depression score than the control group" was supported(F=21.743, p<0.001). Aroma hand massage is an effective nursing intervention for decreased sleep disturbance and depression. Therefore, aroma hand massage by nursing intervention is strongly recommended for improving psychological and physiological functions in hospitalized elderly patients.

• 융합신호처리학회논문지
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• 제19권3호
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• pp.110-117
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• 2018

의수나 의족장치 개발은 전 세계적으로 꾸준히 이루어지고 있으며, 사람의 손과 똑같이 만들어 내거나 감각을 느끼게 하는 것은 힘들겠지만, 물건을 집거나 몇 가지 움직임을 마음먹은 대로 할 수 있다면 절단 장애인들에게는 큰 도움이 될 것이다. 3D프린팅 기술의 발달로 저렴한 의수개발이 가능해졌으며, 이러한 추세에 맞추어 개인맞춤형 의수를 비슷한 가격에 개발할 수 있다면 활용도 및 보급률이 훨씬 높아질 것이다. 본 논문에서는 3D프린팅을 이용하여 사용자 맞춤형 의수를 개발하는 방법에 대해 기술한다. 이를 위해 의수 외형 모델링의 변형수치를 가변값으로 추출하고, 의수 동작을 제어하는 기능을 소프트웨어 디자인 패턴을 이용하여 설계한다. 이를 통해 의수를 필요로 하는 사람들이 각자 원하는 자신만의 의수를 빠르고 저렴한 가격에 갖출 수 있도록 한다.