• The Journal of Korean Physical Therapy
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• v.26 no.2
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• pp.110-116
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• 2014

Purpose: The purpose of study was to investigate the effects of combination patterns exercise of Proprioceptive Neuromuscular Facilitation (PNF) on unstable surfaces on pain, functional disability, and fear avoidance belief in patients with chronic low back pain. Methods: Twenty four patients were assigned to either the experimental group (n=12) or the control group (n=12). Patients in the experimental group performed combination patterns exercise of PNF on unstable surfaces. Patients in the control group performed combination patterns exercise of PNF on stable surfaces. Both exercises were performed for five days per week, for a period of six weeks. Pain was measured by the Visual Analogue Scale (VAS) and University of Alabama at Birmingham (UAB). Functional disability was measured using the Oswestry Disability Index (ODI) and Roland Morris Disability Questionnaire (RMDQ). Fear avoidance belief was measured using the Fear Avoidance Beliefs Questionnaire (FABQ). A paired t-test was used for determination of differences before and after treatment, and an independent t-test was used for determination of differences between treatment groups. Results: In within group comparison, the experimental group showed statistically significant difference for all variables (p<0.05). In comparison between two groups, the experimental group showed relatively greater significant difference for all variables (p<0.05). Conclusion: Based on such results, it can be said that combination patterns exercise of PNF on unstable surfaces has an effect on pain, functional disability, and fear avoidance belief in patients with chronic low back pain.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.5
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• pp.10-16
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• 2003

To investigate the jet effect on circulation control, a segment of model was prepared and inserted horizontally across the test section of the cavitation tunnel. The hydrodynamic forces acting on the model were measured under the 2 dimensional flow behavior. Circulation flow control requires higher flow rate of water jet than boundary layer control does. Jet injection is effective in increasing lift coefficient and the increments reach to 160% in a certain combination of parameters such as an angle of attack, jet flow rate and flap angle. The blown water jet not only reduces form drag but also thrust effect, which is sometimes greater than the form drag in specific conditions.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.110-110
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• 2017

Biological systems offer unique principles for the design and fabrication of engineering platforms (i.e., popularly known as "Biomimetics") for various applications in many fields. For example, the lotus leaves exhibit unique surfaces consisting of evenly distributed micro and nanostructures. These unique surfaces of lotus leaves have the ability of superhydrophobic property to avoid getting wet by the surrounding water (i.e., Lotus effect). Inspired by the surface topographies of lotus leaves, the artificial superhydrophobic surfaces were developed using various micro- and nanoengineering. Here, we propose new platforms that can control hydrophilic and hydrophobic property of surfaces by mimicking micro- and nanosurfaces of various natural leaves such as common camellia, hosta plantaginea, and lotus. Using capillary force lithography technology and polymers in combination with biomimetic design principle, the unique micro- and nanostructures mimicking natural surfaces of common camellia, hosta plantaginea, and lotus were designed and fabricated. We also demonstrated that the replicated polymeric surfaces had different hydrophilic and hydrophobic properties according to the mimicking the natural leaf surfaces, which could be used as a simple, but powerful methodology for design and fabrication of controlled hydrophilic and hydrophobic platforms for various applications in the field of agriculture and biological engineering.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.435-448
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• 2021

This study describes the depth and straight motion control performance depending on control surface combinations of a supercavitating underwater vehicle. When an underwater vehicle experiences supercavitation, friction resistance can be minimized, thus achieving the effect of super-high-speed driving. Six degrees of freedom modeling of the underwater vehicle are performed and the guidance and control loops are designed with not only a cavitator and an elevator, but also a rudder and a differential elevator to improve the stability of the roll and yaw axis. The control performance based on the combination of control surfaces is analyzed by the root-mean-square error for keeping depth and straight motion.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1683-1684
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• 2008

In this paper, a hierarchical nonsingular terminal sliding mode controller (TSMC) for overhead crane system using nonsingular terminal sliding surface (NTSS) is proposed, which can drive the error to zero in a finite time. Here, singular problem of controller is solved by NTSS. In addition, the controller has the double layer structure because the system is divided into two hierarchical subsystems. In the first layer, the nonsingular terminal sliding surfaces are hierarchically designed for each subsystem, and in the second layer, the whole sliding surface is designed as the linear combination of nonsingular terminal sliding surfaces. The asymptotic stability of the system is verified by Lyapunov analysis. Finally, we carry out simulations on the overhead crane system to illustrate the effectiveness of the proposed control method.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.361-368
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• 2009

The efficacy of the combination of Burkholderia cepacia B23 with 0.75% chitosan and 3% calcium chloride ($CaCl_2$) as a biocontrol treatment of anthracnose disease of papaya caused by Colletotrichum gloeosporioides, was evaluated during storage. The growth of B. cepacia B23 in papaya wounds and on fruit surfaces was not affected in presence of chitosan and $CaCl_2$ or combination throughout the storage period. The combination of B. cepacia B23 with chitosan-$CaCl_2$ was more effective in controlling the disease than either B. cepacia B23 or chitosan or other combination treatments both in inoculated and naturally infected fruits. Combining B. cepacia B23 with chitosan-$CaCl_2$ gave the complete control of anthracnose infection in artificially inoculated fruits stored at $14^{\circ}C$ and 95% RH for 18 days, which was similar to that obtained with fungicide $benocide^{(R)}$. Moreover, this combination offered a greater control by reducing 99% disease severity in naturally infected fruits at the end of 14 days storage at $14^{\circ}C$ and 95% RH and six days post ripening at $28\pm2^{\circ}C$, which was superior to that found with $benocide^{(R)}$ or other treatments tested. Thus, postharvest application of B. cepacia B23 with chitosan-$CaCl_2$ as enhancers represents a promising alternative to synthetic fungicides for the control of anthracnose in papaya during storage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.659-665
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• 2010

This paper proposes a control algorithm for quadruped robots moving on irregularly sloped uneven surfaces. Since the body balance of a quadruped robot is controlled by the forces acting on its feet during touchdown, the ground reaction force (GRF) is controlled for stable running. The desired GRF for each foot is generated on the basis of the desired galloping pattern; this GRF is then compared with the actual contact force. The difference between the two forces is used to modify the foot trajectory. The desired force is realized by considering a combination of the rate change of the angular and linear momenta at flight. Then, the amplitude of the GRF to be applied at each foot in order to achieve the desired linear and angular momenta is determined by fuzzy logic. Dynamic simulations of galloping motion were performed using RecurDyn; these simulations show that the proposed control method can be used to achieve stable galloping for a quadruped robot on irregularly sloped uneven surfaces.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.91-91
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• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1302-1311
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• 2003

This paper presents a more stable method of multiresolution editing for a triangular mesh. The basic idea of our paper is to embed an editing area of a mesh onto a 2D region and to produce 3D surfaces which interpolate the editing-information. In this paper, we adopt the extended convex combination approach based on the shape-preserving parameterization for the embedding, which guarantees no self-intersection on the 2D embedded mesh. That is, the result of the embedding is stable. Moreover, we adopt the multi-level B-spline approach to generate the surface containing all of 3D editing-information, which can make us control the editing area in several levels. Hence, this method supports interactive editing and thus can produce intuitive editing results.

• Structural Engineering and Mechanics
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• v.24 no.2
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• pp.155-180
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• 2006

Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.