• The Journal of Korean Physical Therapy
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• v.24 no.3
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• pp.235-239
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• 2012

Purpose: To recognize the change in the proprioception under conditions that activate the local muscles, this study found the difference in the proprioception on a fixed and swing chair. Methods: Healthy adults (7 males, 13 females) in their twenties were evaluated lumbar position sense on fixed and swing chair. And the difference of the position sense between the fixed and swing chair were analyzed. Results: The joint position senses were compared between the fixed and swing chair. As a result, there was a significant difference from all motions. Conclusion: This study found that the improvement of proprioception using swing chair means that the local muscle is activated. Therefore, to use a swing chair, which was designed in this study, is able to replace the general chair either at work or during studies. Thus, this method is easily accessible for busy modern people who are exposed to low back pain or spinal disorders due to a pattern of inactivity.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.3
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• pp.260-265
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• 2013

To increase the machine accuracy by improving the stiffness of spindle bearings, preload was applied to the spindle bearings. The methods of fixed position preload, convertible preload, constant pressure preload, and variable preload are used to apply the preload to the spindle bearing. The previous studies performed by the author of this study were variable preload methods using rubber pressure and centrifugal force based on mechanical systems. This study proposed a toggle joint mechanism that could be applied to variable preload method using centrifugal force and rubber pressure to increase the preload. Also, a finite element analysis was conducted to predict the deformation of the rubber and change of the preload. And the analysis results showed that the preload by the device using rubber pressure only was increased by the toggle joint mechanism using rubber pressure.

• Structural Engineering and Mechanics
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• v.67 no.1
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• pp.1-8
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• 2018

Shake table tests performed on five 1:3 reduced scale two story RC moment resisting frames having construction defects, have shown severe joint damageability in deficient RC frames, resulting in joint panels' cover spalling and core concrete crushing. Haunch retrofitting technique was adopted herein to upgrade the seismic resistance of the deficient RC frames. Additional four deficient RC frames were built and retrofitted with steel haunch; both axially stiffer and deformable with energy dissipation, fixed to the beam-column connections to reduce shear demand on joint panels. The as-built and retrofitted frames' seismic response parameters are calculated and compared to evaluate the viability of haunch retrofitting technique. The haunch retrofitting technique increased the lateral stiffness and strength of the structure, resulting in the increase of structure's overstrength. The retrofitting increased response modification factor R by 60% to 100%. Further, the input excitation PGA was correlated with the lateral roof displacement to derive structure response curve that have shown significant resistance of retrofitted models against input excitations. The technique can significantly enhance the seismic performance of deficient RC frames, particularly against the frequent and rare earthquake events, hence, promising for seismic risk mitigation.

• Journal of Broadcast Engineering
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• v.8 no.2
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• pp.163-171
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• 2003

In this paper, we develop an approach toward Joint Source-Channel Coding for MPEG-4(Moving picture Experts Group) based video coding In fixed and mobile reception environment. We have considered channel environment of AWGN and mobile reception. The source coder used MPEG-4 video. the channel coder used RCPC(Rate Compatible Punctured Convolution) and the modulation method used QPSK(Quadrature Phase Shift Keying) modulation. This study determined optimum Trade-off point between source bit rate and channel coding rate In variable channel states. We compared Joint Source/channel Coding method and general constant bit rate transmission. In this results, Joint Source/channel Coding was appeared better performance than constant bit rate transmission.

• Journal of Communications and Networks
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• v.16 no.6
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• pp.627-638
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• 2014

In this paper, we study the joint price and power allocation in spectrum sharing macro-femtocell networks. The proposed game theoretic framework is based on bi-level Stackelberg game where macro base station (MBS) works as a leader and underlaid femto base stations (FBSs) work as followers. MBS has fixed data rate and imposes interference price on FBSs for maintaining its data rate and earns revenue while FBSs jointly adjust their power for maximizing their data rates and utility functions. Since the interference from FBSs to macro user equipment is kept under a given threshold and FBSs compete against each other for power allocation, there is a need to determine a power allocation strategy which converges to Stackelberg equilibrium. We consider two cases for MBS power allocation, i.e., fixed and dynamic power. MBS can adjust its power in case of dynamic power allocation according to its minimum data rate requirement and number of FBSs willing to share the spectrum. For both cases we consider uniform and non-uniform pricing where MBS charges same price to all FBSs for uniform pricing and different price to each FBS for non-uniform pricing according to its induced interference. We obtain unique closed form solution for each case if the co-interference at FBSs is assumed fixed. And an iterative algorithm which converges rapidly is also proposed to take into account the effect of co-tier interference on interference price and power allocation strategy. The results are explained with numerical simulation examples which validate the effectiveness of our proposed solutions.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.101-123
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• 2011

Objectives : The aim was to study the effect of bee venom pharmacopuncture therapy with different concentration on rheumatoid arthritis rat model. Methods : We enforced a bee venom pharmacopuncture therapy with different concentration on rheumatoid arthritis rat model by the intradermal injection of chicken type II collagen emulsified. 14 days after the onset of the rheumatoid arthritis rat model, a fixed volume of bee venom was daily injected to ST-35 acupoint in the rat's knee joint for 2-3 weeks. The hind paw volume, arthritic index, arthritic flexion pain test, pain threshold, and serum analysis (CRP, $PGE_2$, ALT, AST) were analyzed, and the expression profiles of COX-2, c-fos, and substance-P at the dorsal horn region of the spinal cord and subchondral bone of the knee joint were also analyzed by using the immunohistochemistry. Results : After the treatment of rheumatoid arthritis rats with bee venom pharmacopuncture, the paw volume of edema of arthritic rats were almost restored to the level of normal group, and behavior tests were very effective. Also the evaluation on the blood serum analysis was remarkable. COX-2, c-fos, and substance-P positive cells in the immunohistological section of dorsal horn region of the spinal cord and subchondral bone of the knee joints were significantly decreased. also the bee venom pharmacopuncture was effective to alleviate their rheumatoid arthritic inflammation cytokine inhibition as regards to the behavior tests and joint histological appearance. Conclusions : Based on the results in this study, bee venom pharmacopuncture with concentrated treatment condition was very effective in low fixed quantity and progressive low increased quantity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.139-140
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• 2017

This technology employs a method of forming a single-ply PLUS waterproofing sheet layer comprised of applying a single-ply synthetic polymer layer on a vibrating structure (steel frame, RC) or an inclined surface by using a T joint lap-filling coil and an embedded metal coated sheet. The T - joint reinforcing lap-filling coil was used to block the ingress channel of the rainwater by applying the material in the vulnerable area where the three sides of the waterproof sheet overlapped. Conventional waterproofing techniques have a problem in that the waterproof sheet is pierced because the end portion of the waterproof sheet applied to the vertical portion is fixed by a nail, and the sealant applied to the end portion of the sheet cannot easily secure long-term waterproof durability due to the influence of the external environment. Therefore, the developed technology secured the waterproof durability against the vertical part by using the embedded metal sheet. In addition, automatic hot-air fusing is used to improve the quality of waterproof construction and point fixation method using fixed hardware. This is a technology that is not significantly restricted in the high degradation level regions of domestic waterproof construction environments in Korea such as low-temperature environment, wet floor.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.155-171
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• 2002

The purpose of this study was to provide basic data for a form of gait by comparing and analyzing gait motions on different grades and speeds. In order to accomplish the purpose, 6 university students, whose ages between 20 - 25, were selected. They have gaited on 3Km/h, 4Km/h, 5Km/h of speed and 4 video cameras were used to film them. The speed of filming was 60 frame / seconds. The special variations of kinematics in gait were fixed with ankle joint angle, knee joint angle, hip joint angle, ankle angular velocity, knee angular velocity and hip angular velocity. In this study, the SPSS 10.0 for windows statistical package was used to operate on significant level of .05 for statistical management. From the result of this study, we have succeeded to obtain following conclusions; 1. As the speed increased, the value of ankle joint angle increased. Also the value of ankle joint angle was larger on decline than on incline. 2. As the speed increased, the value of knee joint angle was increased. 3. As the speed increased, the value of hip joint angle was decreased. 4. As the speed increased, the value of ankle angular velocity increased. And the value of ankle angular velocity became higher on decline than on incline. 5. The value of knee angular velocity showed higher on decline than on incline. 6. As the speed increased, the value of hip angular velocity was increased. Also the value of hip angular velocity became higher on incline than on decline.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.35-46
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• 1998

Structural damage is used to be modeled through reductions in the stiffness of structural elements for the purpose of damage estimation of structural system. In this study, the concept of joint damage is employed for more realistic damage assessment of a steel structure. The joint damage is estimated damage based on the mode shape informations using neural networks, The beam-to-column connection in a steel frame structure is represented by a rotational spring at the fixed end of a beam element. The severity of joint damage is defined as the reduction ratio of the connection stiffness with respect to the value of the intact joint. The concept of the substructural identification is used for the localized damage assessment in a large structure. The feasibility of the proposed method is examined using an example with simulated data. It has been found that the joint damages can be reasonably estimated for the case with the measurements of the mode vectors subjected to noise.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.283-292
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• 2016

A computer program code was developed to estimate hydraulic behavior of the 2-D connected pipe network system, and implemented to evaluate the effect of joint aperture on hydraulic parameters of fractured rock masses through numerical experiments. A total of 216 stochastic 2-D DFN(discrete fracture network) blocks of $20m{\times}20m$ were prepared using two joint sets with fixed input parameters of joint orientation, frequency and size distribution. Two different cases of joint aperture variation are considered in this study. The hydraulic parameters were estimated for generated 2-D DFN blocks. The hydraulic anisotropy and the chance for equivalent continuum behavior of the DFN system were found to depend on the variability of joint aperture.