• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.235-242
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• 2005

As the demands in a wireless network are recently increasing, it is necessary to promote the power efficiency of a wireless terminal, and to reduce the overhead of a network. To resolve such problems, we propose the paging technology and the structure of paging area with the joint access point in HPi (High-speed Portable Internet) network, which is being studied as the domestic next-generation IP packet data network. The application of the paging technology to the HPi network possesses the advantage of reducing the registration cost while a terminal in dormant state moves around, and the reporting cost of the terminal's location by the joint access point. The technology suggested in this paper causes the advantages that it promotes the power efficiency in user's point of view while it reduces the network overhead and makes the easy rearrangement of joint APs according to the changes of users' moving pattern in the network manager's point of view.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.104-109
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• 2010

Lap joint friction stir welding(LFSW) is an relatively new solid state joining process. A6061-T6 aluminium alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength to weight ratio and good corrosion resistance. Test methods used in this paper, lock-in thermography, a phase difference between the defect area and the healthy area indicates the qualitative location and size of the defect. In this paper, the defects detected from the thermal image of mechanical properties for weld were evaluated and compared by the lock-in infrared thermography technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5860-5876
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• 2018

A single snapshot data can only provide limited amount of information so that the rank of covariance matrix is not full, which is not adopted to complete the parameter estimation directly using the traditional super-resolution method. Aiming at solving the problem, a joint time delay and angle estimation using matrix pencil method based on information reconstruction vector for orthogonal frequency division multiplexing (OFDM) signal is proposed. Firstly, according to the channel frequency response vector of each array element, the algorithm reconstructs the vector data with delay and angle parameter information from both frequency and space dimensions. Then the enhanced data matrix for the extended array element is constructed, and the parameter vector of time delay and angle is estimated by the two-dimensional matrix pencil (2D MP) algorithm. Finally, the joint estimation of two-dimensional parameters is accomplished by the parameter pairing. The algorithm does not need a pseudo-spectral peak search, and the location of the target can be determined only by a single receiver, which can reduce the overhead of the positioning system. The theoretical analysis and simulation results show that the estimation accuracy of the proposed method in a single snapshot and low signal-to-noise ratio environment is much higher than that of Root Multiple Signal Classification algorithm (Root-MUSIC), and this method also achieves the higher estimation performance and efficiency with lower complexity cost compared to the one-dimensional matrix pencil algorithm.

• Clinical Pain
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• v.18 no.2
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• pp.82-87
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• 2019

Objective: To evaluate which Korean pain descriptors are frequently used in the patients with neuromusculoskeletal diseases and compare the frequency of Korean pain descriptor according to age, gender, pain pattern and intensity, and clinical diagnosis. Method: Two hundreds sixty nine patients with neuromusculoskeletal diseases were enrolled in this study. The patients were asked to fill out a pain questionnaire using Korean. The Korean pain descriptors were collected and classified according to neurophysiological mechanism. The frequency of Korean pain descriptor was analyzed by age, gender, pain pattern and intensity, and clinical diagnosis. They were divided into axial spine and peripheral joint pain group depending on the location of causal disease and shoulder pain descriptors were divided into intra-articular and bursa group. Results: Among 24 Korean pain descriptors, 'arida' was the most common pain descriptor, followed by 'ssusida' and 'jjireunda'. When the pain descriptors were classified according to neurophysiological mechanism, superficial somatic pain was the most common, followed by deep somatic pain. There was a significant difference in the frequency of the pain descriptor between axial spine and peripheral joint pain group (p=0.007). The pain descriptor 'danggida' was used significantly more in the patients with axial spine pain than peripheral joint pain (p=0.024). However, there was no significant difference in other factors. Conclusion: The patients with neuromusculoskeletal diseases expressed their pain using various Korean pain descriptors with stabbing nature and superficial somatic pain. Our results may be helpful to assess and develop a new Korean pain quality measure in the patients with neuromusculoskeletal diseases.

• Journal of the Korean Orthopaedic Association
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• v.56 no.2
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• pp.150-156
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• 2021

Purpose: To determine how the location, displacement, intra-articular involvement, comminution of a 5th metatarsal base fracture affect results of early weight-bearing treatment. Materials and Methods: From January 2013 to July 2017, 34 cases of 34 patients diagnosed with a fracture of the zone I and II 5th metatarsal base were enrolled. The mean follow-up period was 13 months (6-15 months). One patient was excluded as a refracture during the follow-up period, and 33 patients underwent conservative treatment. Anteroposterior, lateral, and simple oblique radiography and computed tomography of the foot were performed to evaluate the location and displacement of the fracture, the degree of joint involvement, and comminution. In all 33 patients, a short leg cast or boot brace was selected immediately after the injury, tolerable weight bearing was allowed. If the pain disappeared, full weight bearing was performed after wearing a plain shoe or postoperative shoe. As a clinical result, the American Orthopedic Foot and Ankle Society (AOFAS) score was evaluated at the final follow-up. During outpatient follow-up, a simple radiograph of the foot was taken to confirm the time of radiological bone union and return to work. Results: Nine males and 24 females, with an average age of 48.7 years, were enrolled in the study. Twenty-four patients had zone I fractures, and nine patients had zone II fractures. Twenty-two out of 33 patients had a fracture displacement of 2 mm or more. Nine and five patients had joint involvement and comminution, respectively. There was a statistically significant return to work from zone I to zone II. The AOFAS score was excellent at the final follow-up and there was no significant difference. When classifying and comparing the degree of fracture displacement, joint involvement, and comminution, there were no significant differences in the radiological union time and return to work. In all cases, satisfactory results were obtained at the final follow-up. Conclusion: Satisfactory clinical results can be obtained by allowing early weight-bearing regardless of the fracture location, displacement, joint involvement, or comminution in zone I and II 5th metatarsal base fractures.

• Korean Journal of Acupuncture
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• v.32 no.3
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• pp.81-89
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• 2015

Objectives : The purpose of this study is to explore the trends of acupoints used for lumbar HIVD(Herniated Intervertebral Disc) and treatment and anatomical location of Hwatahyeopcheock. Methods : We searched the latest clinical studies on acupuncture treatment for lumbar HIVD(Herniated Intervertebral Disc) through domestic studies search. To analyze the data, we categorized them by year and article types of literatures and investigated often-used acupoints and acupuncture types for treatment by reading treatment part of every paper searched. Domestic and Chinese literatures related to Hwatahyeopcheock were also studied for its anatomical location. Results : Total 50 articles are searched and local points are more used than distant points for lumbar HIVD(Herniated Intervertebral Disc) and most of them showed curative effects. Back-su points were used the most and Hwatahyeopcheock use accounted for one-third of the articles. In the articles of Hwatahyeopcheock use, except for one, patients complained of both low back pain and radiating pain, and all of them showed positive results after treatment. Conclusions : Back su point is considered to have its meaning as physical region where patients feel pain including herniated disc level rather than the effect meridian system makes. Through document research and meridian muscle theory, we found that Hwatahyeopcheock means vertebral facet joint, intervertebral foramen and surrounding muscle, nerve, blood vessel and related spinal nerves.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.145-153
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• 1995

Giant cell tumor is most frequently found in juxtaarticular region, and difficult to treat because of local recurrence. Although primary resections reduce recurrence, the joint function will be markedly impaired. Techniques involving physical adjuncts(high speed burr and electric cauterization), acrylic cement or en bloc resection with VFG(vascularized fibular graft) have been employed to reduce local recurrence. From October 1984 to April 1994, twenty-nine patients diagnosed as giant cell tumor were treated at department of Orthopaedic Surgery, School of Medicine, Kyung Hee University. There were eleven men and 18 women, ranging in age from 17 to 52 years(mean: 34 years). The average follow-up period was four years and five months. The location of the lesion was around the knee in 15, distal radius in three, femoral head in three, and others in eight patients. Fifteen patients around the knee joint were treated with several modalities; curettage with bone graft in five, curettage with cement filling in three, curettage with bone graft and physical adjuncts in five, en bloc resection with VFG in one and en bloc resection with arthroplasty in one patient. The functional results, according to the Marshall's knee score, were excellent in one, good in two, and fair in two after the curettage with bone graft, good in three after the curettage with bone cement filling, excellent in one, good in four after the curettage with bone graft and physical adjuncts, and good in two after the en bloc resection with VFG or arthroplasty. Three patients had local recurrence among 15 patients with giant cell tumor around knee. Vascularized fibular graft around wrist joint provided good functional restoration without local recurrence in all three patients who had giant cell tumor in distal radius. Although there is no statistical significance, it seems that curettage with bone graft using physical adjuncts or acrylic cement reveals better results than simple curettage with bone graft. Excellent functional result were obtained without local recurrence by using vascularized fibular graft after en bloc resection.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.535-540
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• 2015

The location of the pivot between the backrest and seat pan of a reclining chair should be identical to the hip joint center to prevent unpleasant user experiences during tilting motion. However, mechanical friction occurs in the pin-in-slot joints that are installed under the seat pan as an alternative to the hinge joint. This reduces the reaction force between the backrest and the occupant's back when reclining and returning to an upright position, which causes the occupant's discomfort. In this study, bearings, rollers, and sliders were suggested as alternatives for the pin component, and the percentage of the reaction force on the backrest was measured while reclining the backrest and subsequently returning it to an upright position. The results show when bearings, rollers, and sliders were used for the pin-in-slot joint, the percentages of the reaction force were $59.7{\pm}10.3$, $47.2{\pm}13.6$, and $30.3{\pm}18.1$, respectively, indicating that the friction of the bearing was the lowest among the three pin components. Because the three alternatives have different manufacturing costs, synthetic judgment requires the consideration of not only mechanical friction but also user experience.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.63-69
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• 2006

Purpose : Marrow edema and fatty degeneration of the hip joint bones could be initial and late signs in hip joint and its bone diseases respectively, which might be differentiated from age-related marrow conversion pattern. So authors have investigated normal marrow conversion pattern of the femur and acetabulum around the hip joints. Materials and methods : Three coronal MR images of 288 hip joint bones in 144 subjects, aged 2 days to 76 years divided to 8 groups every 10 years, were retrospectively analysed for the location and appearance of the converted yellow marrow. The converted yellow marrow were divided to head, neck, and trochanter in the proximal femur and below and above 50% in acetabulum of the hip. Results : The most common type of marrow conversion is the converted yellow marrow in the entire proximal femur and below 50% of acetabulum of the hip. We observed the start of marrow conversion in just before and after 2 years old and stopped at just before and after 20 years old. Conclusion : The understanding of age-related marrow conversion pattern of the hip joint bones would provide some information for differentiation from pathologic condition of them such as edema, fatty degeneration, metastasis, or leukemia.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.319-327
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• 2010

Surface roughness profiles were measured from 19 joint samples using a laser scanner, and Joint Roughness Coefficient (JRC) values were calculated from 30 sections in each sample. Although JRC values varied with the location of the section, the average JRC values from any three sections provides an adequate representation of the average JRC value for the entire surface well. Direct shear tests were performed on nine joints reproduced using molds of real joints in samples of gypsum. The peak friction angles (${\phi}_p$) showed a linear relationship with the average JRC values, yielding the following relationship: ${\phi}_p=41.037+1.046JRC$. However, the shear strengths measured by direct shear tests differed from those calculated using Barton's criterion. The relationship between calculated from direct shear tests and JRC measured from joint surfaces is defined as $JRC_R=f{\cdot}JRC$, and the correction coefficient f is was calculated as $f=3.15JRC^{-0.5}$, as calculated by regression. A modified shear-strength criterion, is proposed using the correction coefficient, ${\tau}={\sigma}_n{\cdot}tan(3.15JRC^{0.5}{\bullet}{\log}_{10}\frac{JCS}{{\sigma}_n}+{\phi}_b)$. This criterion may be effective in calculating the shear strength of moderately weathered rock joints and highly weathered rock joints with low strength and ductile behavior.