• Earthquakes and Structures
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• v.7 no.6
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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.

• Korean Journal of Computational Design and Engineering
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• v.16 no.4
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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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.

• Journal of the Ergonomics Society of Korea
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• v.31 no.4
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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.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.2
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• pp.23-30
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• 2009

Recently, rotation symmetric Boolean functions have attracted attention since they are suitable for fast evaluation and show good cryptographic properties. For example, important problems in coding theory were settled by searching the desired functions in the rotation symmetric function space. Moreover, they are applied to designing fast hashing algorithms. On the other hand, for some homogeneous rotation symmetric quadratic functions of simple structure, the exact formulas for their Hamming weights and nonlinearity were found[2,8]. Very recently, more formulations were carried out for much broader class of the functions[6]. In this paper, we make a further improvement by deriving the formula for the Hamming weight of quadratic rotation symmetric functions containing linear terms.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.74-87
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• 2017

This paper aims to elicit user-defined hand gestures for the small cylindrical displays with flexible displays which has not emerged as a product yet. For this, we first defined the size and functions of a small cylindrical display, and elicited the tasks for operating its functions. Henceforward we implemented the experiment environment which is similar to real cylindrical display usage environment by developing both of a virtual cylindrical display interface and a physical object for operating the virtual cylindrical display. And we showed the results of each task in the virtual cylindrical display to the participants so they could define the hand gestures which are suitable for each task in their opinion. We selected the representative gestures for each task by choosing the gestures of the largest group in each task, and we also calculated agreement scores for each task. Finally we observed mental model of the participants which was applied for eliciting the gestures, based on analyzing the gestures and interview results from the participants.

• Archives of Plastic Surgery
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• v.42 no.5
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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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.2
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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.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.110-117
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• 2018

The development of prosthetic hand or prosthetic leg equipment is steadily taking place globally. Though it would be difficult to create or feel the same way as a human hand, it would be a great for the amputated person if they can pick things up or do some movement as they want. It has become possible to develop low-cost prosthetic hand according to development of 3D printing technology. If people can develop personalized prosthetic equipment at similar prices to meet this trend, the utilization and penetration rate will be much higher. In this study, it describes how to develop a user-customizable prosthetic hand using 3D printing. To do this, the transformational parameters of prosthetic hand shape modeling are extracted as variability values, and the functions for controlling prosthetic hand motion are designed as software design patterns. This allows people who need a prosthetic hand to have their own prosthetic hand at a fast and affordable price.