• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.6
• /
• pp.371-380
• /
• 2023

To calculate seismic fragility, it is important to select input earthquake ground motions that can properly express the characteristics of the target site. This study analyzed the seismic fragility of a single-degree-of-freedom (SDOF) model based on input earthquake ground motions in strong and low-to-moderate seismic regions. As a first step, a total of four sets of input earthquake ground motions were selected,: two sets measured near or far from overseas strong earthquake records and two sets exhibiting the characteristics of low-to-moderate earthquake regions in South Korea. A nonlinear SDOF model for three natural periods was applied to the target structure, and incremental dynamic analysis was used for fragility analysis. In addition, four damage states were defined, and seismic fragility results for each natural period of the nonlinear SDOF model for the four aforementioned input earthquake ground motion sets were obtained for each damage state.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.4
• /
• pp.405-410
• /
• 2011

The purpose of this study was to compare the differences in kinematic variables and grip forces among professionals(PG), amateurs(AG), and novice group(NG) during golf putting. The participants consisted of 3 groups based on their playing ability: 8 professional golfers (handicap<5), 8 amateurs (handicap<18) and 8 novice. Each subject attempted 2.1m putts from the hole. 3D motion analysis system(Motion analysis Corp., USA) with 6 high speed cameras and grip force measurement system(Kim et al., 2007) were used to acquired kinematic and force data, respectively. To compare differences among groups, joint angles of upper limbs, trajectory and smoothness by jerk cost function(JC) of putter head and grip forces were used in this study. Results showed that there were significant differences among groups in most of variables such as joint angles, trajectory & smoothness of putter head, and distribution of grip force in both hands. In brief, we confirmed that putting stroke in PG was more accurate and smooth than that in other groups, especially NG, due to their well-controlled upper limbs and keeping grip forces constant in both hands. It can be concluded that due to skilled levels, fundamental differences of putting movement could be identified and these differences might be helpful for improving one's putting skills.

• Journal of Korean Academy of Nursing
• /
• v.25 no.4
• /
• pp.751-773
• /
• 1995

We, clinical nurse specialists practising and guiding student practice in a Community health nursing clinic, wanted to develop a family pattern appraisal consistent with Rogers' conceptual system, the nursing model guiding our practice. We use Rogers' model because it is harmonious with the traditional Korean view of the one human, natural and cosmic world. The purpose of our research was to contribute to science - based nursing practice, not only, one helpful model, but also a model of how to use, in guiding practice, a conceptual system which reflects nurse practitioners' philosophy of nursing, is intellectually satisfying, and enriches meaning in daily nursing life. The research objectives were to review the literature on Rogers' model and analyse it according to Kim's five - level analytical framework, to explore Rogers' definition of family, to review appraisals based on Rogers' model, and to develop a family appraisal which is culturally appropriate for use in our community. This work including the use of the appraisal and its refinement with families in our practice which was done during 1994 and 1995, in Seoul, in the Capital of the Republic of Korea. At the highest level of analysis, Rogers conceptual system emphasizes acausality and multidimentional meaning ; the world view is characterized by process, movement and wholeness. The epistemology Is one of holism and the knowledge base includes all forms of experience, from sensory to mystical, objective, and subjective. At the metaparadigm level, nursing focuses on the unitary human being and the environment. At the level of nursing philosophy, the model identifies human being, nursing, nurse, and illness and health. At the paradigm level the model assumes the irriducibility of the human to parts, noncausality and continual change. Rogers' practice methodology consists of pattern manifestation appraisal and deliberative mutual patterning. Under-standing patterns and patterning of people is the key to helping them achieve their potential. At the theory level, the basic assumptions, key concepts, and homeodynamic principles were identified. Rogers states the family energy field is an undividable, four-dimensional negentropic energy field which is in a larger envircinmental field show-ing such characteristics as cannot be predicted by knowledge of individual family members. Based on the word of Rogers scholars, we chose Rogers' correlates of patterning to understand the family unit as a whole-frequency, rhythms, motion, time perception, sleeping-waking beyond waking, pragmatic -imaginative-visionary to develop the appraisal. We, also used some of Barrel's (1988) criteria including interpersonal network and professional health care access and use, and Cordon's (1982) criteria including self perception - self concept modified to fit the family. Our family Pattern appraisal included 1. Influencirg data, 2. Professional health care access and use, 3. Family self perception-self concept, 4. Family interpersonal network, 5. Sleep-wake-be-yond waking, 6. Pragmatic-imaginary-visionary, 7. Family frequency and rhythm, 8. Family motion, 9. Family time perception. The appraisal was used with four families and modified to eliminate overlap and to make it possible for the family member to express themselves more easily. We plan to gain more experience with the appraisal toward further development of the tool.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.6
• /
• pp.117-126
• /
• 2010

In the case of failure images with controlling lighting like backlighting and excessive frontlinghting, the compensation scheme for a specific area in an image is required. The interested region is first selected by user in our method to compensate the first frame. Then we define the matching function of brightness and energy function is proposed with weight of matching function and the relationship among the neighbors. Finally, the energy is minimized by the graph-cut algorithm to compensate the brightness of the first frame. Other frames are straightforwardly compensated using the results of the first frame. The brightness variations of the previous frame is transmitted to the next frame via motion vectors. The reliability of the brightness variation is calculated based on the motion vector reliability. Video compensation result is achieved by the process of the image case. Simulation show that the proposed algorithm provides more natural results than the conventional algorithms.

• Journal of Korean Neurosurgical Society
• /
• v.46 no.6
• /
• pp.532-537
• /
• 2009

Objective : Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of $Bryan^{(R)}$ cervical disc prosthesis. Methods : The authors retrospectively reviewed radiographic and clinical outcomes in 52 patients who received the $Bryan^{(R)}$ Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of functional spine unit (FSU), and the C2-7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria, visual analogue pain scale (VAS) and neck disability index (NDI). Results : A total of 71 $Bryan^{(R)}$ disc were placed in 52 patients. A single-level procedure was performed in 36 patients, a two-level procedure in 13 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria, and showed significant improvement by VAS and NDI score (p < 0.05). The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level (p < 0.05). 97% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 88.5% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 70% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 66.6% of the patients postoperatively. Conclusion : Arthroplasty using the $Bryan^{(R)}$ disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although the early results are promising, this is a relatively new approach, therefore long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.

• The Journal of Engineering Geology
• /
• v.17 no.1 s.50
• /
• pp.1-13
• /
• 2007

In order to evaluate the local site effects at two town fortress areas in Korea where stone parapets were col-lapsed by historical earthquakes, site characteristics were assessed using site investigations such as borehole drillings and seismic tests. Equivalent-linear site response analyses were conducted based on the shear ways velocity ($V_s$) profiles and geotechnical characteristics determined from site investigations. The study sites are categorized as site classes C and B according to the mean $V_s$ to 30 m ranging from 500 to 850 m/s, and their site periods are distributed in the short period range of 0.06 to 0.16 sec, which contains the natural period of fortress wall and stone parapet. From the results of site response analyses in the study areas, for site class C indicating most of site conditions, contrary to site class B, the short-period (0.1-0.5 sec) and mid-period (0.4-2.0 sec) site coefficients, $F_a$ and $F_v$ specified in the Korean seismic design guide, underestimate the ground motion in short-period band and overestimate the ground motion in mid-period band, respectively, due to the high amplification in short period range, which represent the site-specific seismic response characteristics. These site-specific response characteristics indicate the potential of resonance in fortress walls during earthquake and furthermore could strongly affect the collapse of parapets resulted from seismic events in historical records.

• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.2
• /
• pp.85-97
• /
• 2001

A mathematical model was proposed to analyze the damped motion of contact lens which is initially displaced from the equilibrium position. The model incorporates the differential equations and their numerical solution program, based on the formulations of restoring force arising from the capillary action in the tear-film layer between the lens and cornea. The model predicts the capillary action induced surface tension, time dependence of displacement of lens when it is released from the equilibrium position. It seems that the motion of lens is similar to the typical over-damped oscillation caused by the large viscous friction in the liquid layer between the cornea and lens. The effect of variables such as base curves, lens diameters and thickness of tear film layer were illustrated by the computer simulation of the derived program. The time required for the lens to return to the original position increases as the liquid layer thickness increases and it decreases as the diameter of lens increases. With the certain value of base curve the time interval is found to be minimum. The free vibrations of lenses were also simulated varying the parameters such as base curve, diameter, layer thickness. The resonant frequencies are inversely proportional to the liquid layer thickness and it increases as the lens diameter increases. The resonant frequency of lens has a maximum when the diameter is of certain value. If the external impulse or force of the same frequency as the natural frequency of contact lens acted on the cornea in vivo it may cause an excessive movement and thus it might cause the distortion 10 the lens or be pulled off the eye.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.11
• /
• pp.2095-2102
• /
• 2017

In this paper, we implemented the elderly home training contents provide individual exercise prescription according to the user's athletic ability and provide personalized program to the elderly individual. Health promotion is essential for overcoming the low health longevity of senior citizens preparing for aging population. Therefore, the lower body strengthening exercise to prevent falls is crucial to prevent a fall in the number of deaths of senior citizens. In this game model, the elderly are aiming at home training contents that can be found to feel that the elderly are going out of walk and exercising in the natural environment. To achieve this, Kinect extracts a specific bone model provide by the Kinect Sensor to generate the feature vectors and recognizes the movements and motion of the user. The recognition test using the Kinect sensor showed a recognition rate of about 80 to 97%.

• Journal of KIISE:Software and Applications
• /
• v.35 no.12
• /
• pp.780-788
• /
• 2008

Modeling hand poses and tracking its movement are one of the challenging problems in computer vision. There are two typical approaches for the reconstruction of hand poses in 3D, depending on the number of cameras from which images are captured. One is to capture images from multiple cameras or a stereo camera. The other is to capture images from a single camera. The former approach is relatively limited, because of the environmental constraints for setting up multiple cameras. In this paper we propose a method of reconstructing 3D hand poses from a 2D input image sequence captured from a single camera by means of Belief Propagation in a graphical model and recognizing a finger clicking motion using a hidden Markov model. We define a graphical model with hidden nodes representing joints of a hand, and observable nodes with the features extracted from a 2D input image sequence. To track hand poses in 3D, we use a Belief Propagation algorithm, which provides a robust and unified framework for inference in a graphical model. From the estimated 3D hand pose we extract the information for each finger's motion, which is then fed into a hidden Markov model. To recognize natural finger actions, we consider the movements of all the fingers to recognize a single finger's action. We applied the proposed method to a virtual keypad system and the result showed a high recognition rate of 94.66% with 300 test data.

• Science of Emotion and Sensibility
• /
• v.13 no.1
• /
• pp.103-110
• /
• 2010

TPR(Total Physical Response) is a new representative learning method for children's education. Today's approach to TPR has focused on signals from a user which becomes input data in a human-computer interaction, but the accuracy of sensing from body signals(e. g. motion and voice) isn't so perfect that it seems difficult to apply on an education system. To overcome these limits, we suggest a mediating interface device which can detect the user's motion using correct numerical values such as acceleration and angular speed. In addition, we suggest new design requirements for the mediating device through analyzing children's behavior as human factors by ethnography research and protocol analysis. As a result, we found that; children are unskilled in physical control when they use objects; tend to lean on an object unconsciously with touch. Also their behaviors are restricted, when they use objects. Therefore a mediating device should satisfy new design requirements which are make up for unskilled handling, support familiar and natural physical activity.