• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.413-420
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• 1997

In this paper, we analyzed the contraction patterns of active elbow muscles during isometric, concentric and eccentric contraction. The analysis parameters consist of frequency domain parameters (mean frequency, median frequency, peak frequency, peak power, skewness, kurtosis) and time domain paraseters (zero crossing, positive maxima, integrated EMG). The results of this study were as follows; The BR/BB of isometric contraction appeared to be Venter as the elbow joint was more extended. The BR /BB during concentric and eccentric contraction tended to increase with more extension of the elbow joint angle, but there was no significant difference between concentric and eccentric contraction. Further, the EMG power spectrum due to the type of contraction were different betwen eccentric and concentric contraction. According to the results, it was found that the activation pattern in elbow flexor muscles was different during three different muscle contraction pattern. Therefore, elbow flexor muscles should not be considered a single functioning unit. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness kurtosis can be useful parameters in functional recognition for prosthesis control purpose.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.325-334
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• 2016

This study explores developing a large round table with Bosang flower pattern for a contemporary meeting room made by a cabinet maker, Kim Byeung-soo, who has built the traditional Korean furniture in Korean Western Gyeongnam Province since after his elementary school. He uses the post finger joint from one of the middle level of his education process based on the traditional Korean technique, develops it into flower stem joint, and adds flower patterns' carving decoration called Bosang flower patterns. Hence, the table makes the table be strong, useful, and beautiful. Therefore, the modernized round table will be able to make the people access more easily and to make more demand on the traditional Korean furniture and the adopted furniture than ever.

• The Korean Journal of Pain
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• v.37 no.1
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• pp.3-12
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• 2024

One of the most common sources of spinal pain syndromes is the facet joints. Cervical, thoracic, and lumbar facet joint pain syndromes comprise 55%, 42%, and 31% of chronic spinal pain syndromes, respectively. Common facet joint disorders are degenerative disorders, such as osteoarthritis, hypertrophied superior articular process, and facet joint cysts; septic arthritis; systemic and metabolic disorders, such as ankylosing spondylitis or gout; and traumatic dislocations. The facet pain syndrome from osteoarthritis is suspected from a patient's history (referred pain pattern) and physical examination (tenderness). Other facet joint disorders may cause radicular pain if mass effect from a facet joint cyst, hypertrophied superior articular process, or tumors compress the dorsal root ganglion. However, a high degree of morphological change does not always provoke pain. The superiority of innervating nerve block or direct joint injection for diagnosis and treatment is still a controversy. Treatment includes facet joint injection in facet joint osteoarthritis or whiplash injury provoking referred pain or decompression in mass effect in cases of hypertrophied superior articular process or facet joint cyst eliciting radicular pain. In addition, septic arthritis is treated using a proper antibiotic, based on infected tissue or blood culture. This review describes the diagnosis and treatment of common facet joint disorders.

• Earthquakes and Structures
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• v.17 no.6
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• pp.611-621
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• 2019

Precast concrete structure has many advantages, but the assembled seam will affect potentially the overall seismic performance of structure. Based on the sidewall joint located in the bottom of assembled monolithic subway station, the main objectives of this study are, on one hand to present an experimental campaign on the seismic behavior of precast sidewall joint (PWJ) and cast-in-place sidewall joint (CWJ) subjected to low-cycle repeated loading, and on the other hand to explore the effect of shape and position of assembled seam on load carrying capacity and crack width of precast sidewall joint. Two full-scale specimens were designed and tested. The important index of failure pattern, loading carrying capacity, deformation performance and crack width were evaluated and compared. Based on the test results, a series of different height and variably-shape of assembled seam of precast sidewall joint were considered. The test and numerical investigations indicate that, (1) the carrying capacity and deformation capacity of precast sidewall and cast-in-place sidewall were very similar, but the crack failure pattern, bending deformation and shearing deformation in the plastic hinge zone were different obviously; (2) the influence of the assembled seam should be considered when precast underground structures located in the aquifer water-bearing stratum; (3) the optimal assembled seam shape and position can be suggested for the design of precast underground concrete structures according to the analysis results.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.221-230
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• 2019

In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.

• Smart Structures and Systems
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• v.22 no.4
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• pp.459-468
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• 2018

In this paper, the effect of non-persistent joints was determined on the behavior of concrete specimens subjected to biaxial loading through numerical modeling using particle flow code in two dimensions (PFC2D). Firstly, a numerical model was calibrated by uniaxial, Brazilian and triaxial experimental results to ensure the conformity of the simulated numerical model's response. Secondly, sixteen rectangular models with dimension of 100 mm by 100 mm were developed. Each model contains two non-persistent joints with lengths of 40 mm and 20 mm, respectively. The angularity of the larger joint changes from $30^{\circ}$ to $90^{\circ}$. In each configuration, the small joint angularity changes from $0^{\circ}$ to $90^{\circ}$ in $30^{\circ}$ increments. All of the models were under confining stress of 1 MPa. By using of the biaxial test configuration, the failure process was visually observed. Discrete element simulations demonstrated that macro shear fractures in models are because of microscopic tensile breakage of a large number of bonded discs. The failure pattern in Rock Bridge is mostly affected by joint overlapping whereas the biaxial strength is closely related to the failure pattern.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.90-96
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• 2010

Joint transform correlator (JTC) has been the most suitable technique for real time pattern recognition. This paper proposes a new phase adjustment which adopts two steps of random phase adjustment in the spatial domain and additional phase adjustment in the Fourier domain. Simulated results are presented to show the optimum condition of the phase adjustment and the effect on the correlation peaks, the peak signal-to-noise ratio and the level of discrimination.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.472-476
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• 2014

The Joint Transform Correlator (JTC) has been the most suitable technique for real time optical pattern recognition and target tracking applications. This paper proposes a new application of the JTC system for an analysis of the blurring effect of the optical images caused by a defocused lens. We present the relation between the correlation peak, optical transfer function (OTF), and the amount of blurring caused by focusing error. Moreover, we show a possibility of calibrating the blurred image by simply measuring the correlation peak.

• Journal of Korean Foot and Ankle Society
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• v.16 no.4
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• pp.203-209
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• 2012

Lisfranc joint injuries are rare and account for 0.2% of all injuries. The pattern of Lisfranc injuries varies from low-energy ligamentous sprain to high-energy fractures or crushing injuries. Early diagnosis and appropriate treatment of Lisfranc injuries are important to prevent chronic foot pain and dysfunction.

• Journal of the Ergonomics Society of Korea
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• v.20 no.3
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• pp.11-25
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• 2001

AS human movements have the inherent property of anticipating target and can be coordinated to realize a given schedule, finger movements have stereotyped patterns during hand grasping. Finger movements have been studied in the past to find out the coordination pattern of hand joint angular movement. These studies analyzed only a few finger joints for a limited number of hand postures. This study investigated fourteen joint angles during eight hand-grasping motions to analyze the angular correlations between finger joints and to suggest motion factors which represent hand grasping. Hand grasping motions including forward arm motion were examined in ten healthy volunteers. Eight objects were used to represent real hand grasping tasks. $CyberGlove^{TM}$ and $Fasreack^{TM}$ measured hand joint angles and wrist origin. Joint angle correlations between PIJ(proximal interphalangeal joint) and MPJ(metacarpophalangeal joint) at one finger, between neighboring PIJs and MPJs were four factors related to the fast phase of hand grasping motions and eight factors related to the slow phase of hand grasping motions.