• Tribology and Lubricants
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• v.13 no.1
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• pp.82-87
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• 1997

The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires a re-replacement of hip joints because it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focussed on the development of new materials. The research of new materials, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find new combinations of bio-materials in the total hip replacement which has the excellent contact characteristics. A non-linear FEM program MARC with 5-node axisymmetric element was used for analyzing the contact stresses between the hip joints. The computed results show that in case of acetabulum UHMWP has good characteristics, in femoral head, $Al_2O_3$, and in stem, Ti6Al4V.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1041-1062
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• 2012

In this paper, we propose a hybrid cooperative scheme to improve the secrecy rate for a cooperative network in presence of multiple relays. Each relay node transmits the mixed signal consisting of weighted source signal and intentional noise. The problem of power allocation, the joint design of beamforming and jamming weights are investigated, and an iterative scheme is proposed. It is demonstrated by the numerical results that the proposed hybrid scheme further improves secrecy rate, as compared to traditional cooperative schemes.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.4-5
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• 2021

In this study, in the coating-sheet composite waterproofing method, a specimen was formed to prevent the transmission of the no-node tensile stress occurring under the junction between sheets by forming an insulating structure when the junction was formed, and to compare the effect of preventing breakage with the existing common junction. For this, tensile performance evaluation was conducted. As a result of the evaluation, it was confirmed that it exhibited higher tensile strength compared to the existing joint and at the same time exhibited a large width of displacement characteristics, and thus, had an effect of preventing breakage.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.4
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• pp.33-49
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• 2010

Objectives : This study was designed to elucidate the anti-pathogenetic and curative effects of Gyehyeoldeungbokhap-bang(Jixietengfuge-fang, GCP) on Type II collagen-induced arthritis(CIA) in mice. Methods : In experiment, twenty four mices were divided into non-treated normal group(n=6), bovine type II collagen-induced control group(n=6), collagen immunized and treated two group medicated with extract of GCP(concentration of extraction: 200 mg/kg n=6, 400 mg/kg n=6) for 4 weeks after collagen immunization, Various experimental such as arthritis, incidence, index, total cell number of spleen, total cell number of peripheral lymph node(PLN), paw joint total cell number, analysis on the percentage of immunofluorescent cells of spleen in CIA induced mice, effects of inflammatory gene expression in spleen, PLN and paw joint of CIA mice, production of cytokine(IFN-${\gamma}$, IL-4, TNF-${\alpha}$, IL-6), analysis of rheumatoid factor(anti-collagen lgG, lgM level in serum) and histopathological study on the paw joint. The arthritis index, incidence were measured a week over 4 weeks after second boosting. Total cell number of spleen, peripheral lymph node, paw joint were measure after performed experiment over 7 weeks. Concentration of cytokine and rheumatoid factor in serum were measured after experiment finished. Histopathological study on the paw joint was measured after 40 days medicated with extract of GCP. Results : 1. Incidence of arthritis and index of arthritis were significantly decreased in treated group with 400 mg/kg. 2. Total cell number of spleen, PLN and paw joint were significantly decreased in treated group. 3. Analysis on the percentage of immunofluorescent cells of spleen in CIA induced mice were significantly controled compare with control group. 4. Effects of inflammatory gene expression in spleen, PLN and paw joint of CIA induced mice were significantly controled compare with control group. 5. IFN-${\gamma}$, IL-6, TNF-${\alpha}$, concentration($pg/m{\ell}$) in serum of treated group was significantly decreased compare with control group. But IL-4 was significantly increased. 6. lgM and lgG concentration($pg/m{\ell}$) in serum of treated group was significantly decreased compare with control group. 7. Histopathologically, suppurative and destructive lesion of synovial membrane, articular cartilage and subchondral bony tissue in treated group were alleviated compare with those of control group. Conclusions : Based on the results described above, it might be consider that Gyehyeoldeungbokhap-bang(Jixietengfuge-fang, GCP) has antiarthritic and analgesic effects and also inhibitory effects on the progression of collagen-induced arthritis mice.

• Journal of Chest Surgery
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• v.21 no.5
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• pp.856-862
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• 1988

The survival rate after resectional operation for carcinoma of the esophagus is still very low and many factors contribute to these poor results. We analyze the clinical results of 56 operated patients among 62 esophageal cancer patients between March, 1974 and July, 1988. Among the 62 patients, 52 patients were squamous cell carcinoma and 8 were adenocarcinoma, one was leiomyosarcoma and one was adenosquamous cell carcinoma. The classification of esophageal cancer was based on TNM classification of American Joint Committee on cancer". Among the operated patients, stage I was 5[9.6%], stage II was 13[25%], stage III was 26[50%], stage IV was 8[15.4%]. And its one year survival rate was 80%, 69%, 11.5%, 0% for each stages. The rate of resectability was 30.3% and resection of esophagus with esophagogastrostomy and extended lymph node dissection was performed on 17 patients without distant metastasis or adjacent organ invasion. Substernal esophago-colono-gastrostomy, Celestine tube insertion and feeding gastrostomy was performed on remained 39 patients. The analysis of postoperative survival duration revealed the superiority of esophagectomy with extended lymph node dissection over other palliative operation. [1 year survival rate: 79% versus 21%] We concluded that the survival rate of esophageal resection with lymph node dissection group was superior to nonresective palliative operation group. And transthoracic approach was superior to extrathoracic approach in involved lymph node dissection and esophageal resection in locally invaded cases.ases.

• Steel and Composite Structures
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• v.22 no.1
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• pp.45-61
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• 2016

The domestic and foreign scholars conducted many studies on mechanical properties of wave web steel beam and high-strength spiral stirrups confined concrete columns. Based on the previous research work, studies were conducted on the anti-seismic property of the end plate bolt connected wave web steel beam and high-strength spiral stirrups confined concrete column nodes applied with pre-tightening force. Four full-size node test models in two groups were designed for low-cycle repeated loading quasi-static test. Through observation of the stress, distortion, failure process and failure mode of node models, analysis was made on its load-carrying capacity, deformation performance and energy dissipation capacity, and the reliability of the new node was verified. The results showed that: under action of the beam-end stiffener, the plastic hinges on the end of wave web steel beam are displaced outward and played its role of energy dissipation capacity. The study results provided reliable theoretical basis for the engineering application of the new types of nodes.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.1
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• pp.56-64
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• 2013

TICN, a next-generation tactical communication network based on a wireless network, acts as the backbone of the whole network. TICN requires the routing which takes both survivability of passage, reliability, and safety of wireless link into consideration. A tactical network like TICN may maintain the passage for just a short period of time due to topology's frequent changes; In this process all nodes, dependent on batteries for their necessary energy, are restricted by batteries' durability in due course. To overcome this shortcoming, the up-to-date protocols consider only either of diminishing or balancing out energy consumptions. Thus there was a limitation to enhancing both throughput and energy efficiency. The thesis proposes a protocol which regards both throughput and energy efficiency, and enhances node survivability by means of minimizing and balancing energy consumption of the whole network. The protocol brings out an improvement in throughput and makes each node's energy usage more effective.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.4
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• pp.1373-1391
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• 2022

We investigate mobile multiple-input multiple-output (MIMO) molecular communication via diffusion (MCvD) system which is consisted of two source nodes, two destination nodes and one relay node in the mobile three-dimensional channel. First, the combinations of decode-and-forward (DF) relaying protocol and network coding (NC) scheme are implemented at relay node. The adaptive thresholds at relay node and destination nodes can be obtained by maximum a posteriori (MAP) probability detection method. Then the mathematical expressions of the average bit error probability (BEP) of this mobile MIMO MCvD system based on DF and NC scheme are derived. Furthermore, in order to minimize the average BEP, we establish the optimization problem with optimization variables which include the ratio of the number of emitted molecules at two source nodes and the initial position of relay node. We put forward an iterative scheme based on block coordinate descent algorithm which can be used to solve the optimization problem and get optimal values of the optimization variables simultaneously. Finally, the numerical results reveal that the proposed iterative method has good convergence behavior. The average BEP performance of this system can be improved by performing the joint optimizations.

• Journal of IKEEE
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• v.16 no.3
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• pp.235-243
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• 2012

In this study, we developed two legged multi-joint robot by using wireless servo motor that was applied by wireless sensor network technology, which is widely used recently, and performed an experiment of walking method of two legged multi-joint robot. We constructed the star network with servo motors which were used at each joint of two-legged robot. And we designed the robot for operation by transmission of joint control signal from main control system or by transmission of the status of each joint to the main control system, so it operates with continuously checking the status of joints at same time. We developed the humanoid robot by using wireless digital servo motor which is different from existing servo motor control system, and controlled it by transmitting the information of angles and speeds of robot joints to the motor(node) as a feedback through main control system after connecting power and setting up the IDs to each joint. We solved noisy problem generated from wire and wire length to connection point of the control device by construction of the wireless network instead of using existing control method of wiring, and also solved problem of poor real time response to gait motion by controlling the position with continuous transmission of control signals to each joint. And we found that the effective control of robot is able by performing the simulation on walking motion in advance with the developed control algorithm which was downloaded into installed memory. Also we performed the stable walking with two-legged robot by attaching pressure sensor to robot sole. And we examined the robot gait operated by application of calculated algorithm on robot movement to each joint. In this study, we studied the method of controlling robot gait motion by using wireless servo motors and measured the torque applied to each joint, and found that the developed wireless servo motor by ZigBee sensor network offers easier control of two legged robot gait and better circuit configuration of it than the existing wired control system could do.

• Structural Engineering and Mechanics
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• v.87 no.2
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• pp.137-149
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• 2023

In this study, to explore the working performance of the CFST split spherical node wind power tower, two groups of CFST split spherical joint plane towers with different web wall thicknesses and a set of space systems were analyzed. The tower was subjected to a low-cycle repeated load test, and the hysteresis and skeleton curves were analyzed. ABAQUS finite element simulation was used for verification and comparison, and on this basis parameter expansion analysis was carried out. The results show that the failure mode of the wind power tower was divided into weld tear damage between belly bar, high strength bolt thread damage and belly rod flexion damage. In addition, increasing the wall thickness of the web member could render the hysteresis curve fuller. Finally, the bearing capacity of the separated spherical node wind power tower was high, but its plastic deformation ability was poor. The ultimate bearing capacity and ductility coefficient of the simulated specimens are positively correlated with web diameter ratio and web column stiffness ratio. When the diameter ratio of the web member was greater than 0.13, or the stiffness ratio γ of the web member to the column was greater than 0.022, the increase of the ultimate bearing capacity and ductility coefficient decreased significantly. In order to maximize the overall mechanical performance of the tower and improve its economy, it was suggested that the diameter ratio of the ventral rod be 0.11-0.13, while the stiffness ratio γ should be 0.02-0.022.