• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.343-351
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• 2015

Objective : The purpose of this study was to investigate the effects in the muscle function following 8-week dead-lift training with Whole-body Vibration(WBV) in rehabilitation for sports players. Method : Twenty young sports players. Each subjects were randomly assigned to a resistance training with Whole-body vibration group(TG, n=10), a resistance training without Whole-body vibration group(CG, N=10). The measurements which physical fitness test and joint torque test were performed before the randomization and after the 4-week and 8-week. The WBV group performed the dynamic Dead-lift exercise on a vibration platform during one minute. The CG group performed the equal training without vibration. The WBV and CON group repeated 5 set and trained two times weekly for 8-weeks. Paired t-test was used to test for differences between the groups at baseline and after 4-weeks and 8-Weeks. And independent t-test was used to test for differences between the groups at TG and CG. All analyses were executed using SPSS software 18.0. The level of significance was set at p<.050. Results : Following the 8-Weeks training sessions, an increase in the back-muscle strength was found to be greater for the TG compared with the CG group(p<.05). Muscle endurance was significantly decreased after training than before training only for the CG(p<.05). Isometric Hip/Lumber Extension/Flextion measurement was found to be significantly greater for the TG compared with the CG group(p<.05). The finding indicates that WBV effects as an efficient training stimulus to enhance muscle function by facilitating neural control trail. Following muscle activation in motor unit synchronization of the co-contraction of the muscles. Conclusion : The results imply that the WBV training may have enhanced muscle function in rehabilitation for sports players.

• Journal of the Korean Association of Geographic Information Studies
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• v.5 no.4
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• pp.93-105
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• 2002

In this paper forest fire status information management system was developed under web environment using web GIS(geographic information system) technology. Though this system, general users can easily retrieval domestic forest fire status information and obtain that in visual way such as maps, graphs, and texts if they have only certain web browsers. Moreover, officials, who have system access authority, can easily control and manage all domestic forest fire status information through input interface, retrieval interface, and out interface of the system. This system can be considered as the first domestic system to manage forest fire status data and service them in visual through user friendly interfaces on web. In order to implement this system, IIS 5.0 of Microsoft is used as web server and Oracle 8i and ASP(active server page) are used for database construction and dynamic web page operation, respectively. Also, ArcGIS IMS(internet map server) of ESRI is used to serve maps by using Java and HTML as system development languages. Not only the domestic tendency of forest fire but also the forest fire status information of certain area and time such as the frequency and the loss can be presented through distribution maps, graphs and tables. Therefore, this system is supposed to play as a important role when the policy relate to domestic forest fire is established. In addition, the self consciousness of people against forest fire can be inspired and the foundation of scientific and systemic forest fire services can be obtained through this system in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.875-888
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• 2013

The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.

• Journal of Navigation and Port Research
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• v.29 no.1 s.97
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• pp.9-15
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• 2005

To design ship channel is one of important factors for planning and developing a port. In most case, the core factors for designing ship channel are the layout and width of channel provided the net underkeel clearance is secured to be safe enough to pass. In this study, Variable Bumper Area(VBA) model is applied to design and assess ship channel. This model reflects ship's particular, ship domain theory, ship speed and mariner's ship handling skill and experience, especially external forces which cause leeway, set and drift and the change of ship maneuvering characteristics. A real time, full mission shiphandling simulator is used to analyze ship dynamic data according to mariner's ship control, external forces, ete. This model defines Domain degree and Domain-index for assessing the efficiency and safety of the channel. The proposed model is applied to Ulsan new port plan which has a channel width of 1.5 times the length of the largest vessel, a radius of 5 times the length of the largest vessel in a curve of 57 degree centerline angle and SBM facility adjacent to the lateral edge of channel. The result of this study shows that the width of the channel and radius of channel curve are suitable for the target ship but the difficulty of ship handling is caused by the large course change and SBM located in the vicinity of channel.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.5
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• pp.419-426
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• 2018

For an orbit transfer in a space exploration mission, a solid or liquid rocket booster is included at the last stage of the launch vehicle. During the orbit transfer, thrust misalignment can cause a severe orbit error. Three axis attitude control or spin stabilization can be implemented to minimize the error. Spin stabilization technique has advantages in structural simplicity and lightness. One of ways to apply the spin stabilization to the payload is to include a spin table system in the launch vehicle. In this paper, effect of the spin table system on separation dynamics of the payload is analyzed. Simple model of the spin table to mimic basic functions is designed and simulation environment is established with the model. Effect of the spin table is tested by evaluating separation dynamics of a payload with and without the spin table. Analysis on tolerance effect of separation spring constant on separation dynamics of a payload is conducted.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.363-363
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• 2014

Ruthenium (Ru) has attractive material properties due to its promising characteristics such as a low resistivity ($7.1{\mu}{\Omega}{\cdot}cm$ in the bulk), a high work function of 4.7 eV, and feasibility for the dry etch process. These properties make Ru films appropriate for various applications in the state-of-art semiconductor device technologies. Thus, it has been widely investigated as an electrode for capacitor in the dynamic random access memory (DRAM), a metal gate for metal-oxide semiconductor field effect transistor (MOSFET), and a seed layer for Cu metallization. Due to the continuous shrinkage of microelectronic devices, better deposition processes for Ru thin films are critically required with excellent step coverages in high aspect ratio (AR) structures. In these respects, atomic layer deposition (ALD) is a viable solution for preparing Ru thin films because it enables atomic-scale control of the film thickness with excellent conformality. A recent investigation reported that the nucleation of ALD-Ru film was enhanced considerably by using a zero-valent metallorganic precursor, compared to the utilization of precursors with higher metal valences. In this study, we will present our research results on the synthesis and characterization of novel ruthenium complexes. The ruthenium compounds were easy synthesized by the reaction of ruthenium halide with appropriate organic ligands in protic solvent, and characterized by NMR, elemental analysis and thermogravimetric analysis. The molecular structures of the complexes were studied by single crystal diffraction. ALD of Ru film was demonstrated using the new Ru metallorganic precursor and O2 as the Ru source and reactant, respectively, at the deposition temperatures of $300-350^{\circ}C$. Self-limited reaction behavior was observed as increasing Ru precursor and O2 pulse time, suggesting that newly developed Ru precursor is applicable for ALD process. Detailed discussions on the chemical and structural properties of Ru thin films as well as its growth behavior using new Ru precursor will be also presented.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.119-126
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• 2011

During precise survey on the top of High rise buildings and civil structures, optical surveying equipments like a Total Station are not recommended to use because of some reasons that uneasier alignment with reflectors located at the top of building, increasing error depends on increasement of observation distance and unavailable dynamic positioning etc. Recently various GPS positioning methods have been applied to this job however almost of them are post-processing method which is required much longer time during for whole process includes stake-out, cross checking, fixing positions and final inspections. Therefore, in this study, we applied with RTK surveying system which allows stake-out and inspection in realtime to avoid delaying of construction schedule and also applied with Quasi Static RTK measurement and network adjustment to get a high accuracy within a few millimeters in structure positioning to achieve a successful management for process and quality control of the project. As a result, very high accurate surveying for structures within approx. 2mm in realtime has been achieved when surveyor conduct a network adjustment using least square method for 4 base lines created by Quasi Static RTK data and we expect this method will be applied to construction survey for high rise buildings and civil structures in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6C
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• pp.251-258
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• 2011

Steel pipe piles have been used as various deep foundation materials for a long time. Recent increase in steel material cost has made engineers reluctant in using it even with its good quality and ease of construction. Therefore when constructing with steel pipe pile, the decision to reuse the excessive pile length that is cut off from the designed pile head elevation after pile driving can be cost saving. This has caused many constructors to reuse the pile leftovers with new piles, but the absence of quantitative structural capacity behaviors of steel pipe pile after pile driving or appropriate countermeasures and standards in reusing steel pipe pile has resulted in wrong applications, pile structural integrity problems, inappropriate limitation of reusable pile length, etc. The structural performance analysis between a new pile and a pile that has undergone working state and ultimate state stress level during pile driving was performed in this research by means of comparing the results between the dynamic pile load test, tensile load test, charpy energy test and fatigue test for high strength steel of $440N/mm^2$ yield strength. Test results show that under working load conditions the yield strength variation is less than 2% and for ultimate load conditions the variation is less than 5% for maximum total blow count of 3000. The results have been statistically analyzed to check the sensitivity of each factors involved. From the test results, reusability of steel pipe pile lies not in the main pipe yield strength deviation but in the reduction of absorb energy, strength changes and quality control at the welded section, shape deformation and local buckling during pile driving.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.361-371
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• 2009

LAMS(learning activity management system)[1] is one of the useful tools for designing and managing effectively the learning activities such as web search, chat, forum, grouping, and board. Even if LAMS has been upgraded to support the methods for making e-Learning contents conveniently, it does not have a method to communicate with external educational contents (EEC) made by external tools like Flash, Java, Visual C++, and so on. LAMS, which has been operated on Web environment, should manage all EECs like video and dynamic educational contents as educational contents in LAMS database. However, the current LAMS does not support the functionalities which can provide information of EECs to LAMS database and can also access any information about EECs from the database yet. In this paper, we propose the communication mechanism between the LAMS and EECs for solving the problem. In special, the mechanism makes many statistical data by using the information, and provides them for reflecting in education, and can control various learning management that was impossible under the original LAMS. Based on the proposed mechanism, teachers using LAMS can make more various educational contents and can manage them in the system.

• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.29-36
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• 2011

Purpose: The purpose of this study was to evaluate the effect of 6-week sensorimotoor training on balance ability and lower limb muscle activation during gait in older adults. Methods: Twenty-four community-dwelling older adults between 65 and 90 years of age participated in this study. In the older adults of the experimental group (n=12), the sensorimotor training program was performed bare feet. General exercise was performed in the control group (n=12). Then, both groups exercised three times a week for forty minutes over a 6-week period. Balance ability was evaluated by One leg stand (OLS) test for determining the static balance and Timed Up & Go (TUG) test for determining the dynamic balance. In addition, muscle activation of the dominant lower limb tibialis anterior and gastrocnemius medialis muscles were measured by surface EMG to evaluate muscle activation during gait. Results: A significant improvement was seen in the one leg standing (OLS) time after exercise in both the sensorimotor training (SMT) group and general exercise (GE) group (p<0.05) and the change in the SMT group was greater than that in the GE group (p<0.05). A significant reduction was seen in the Timed Up & Go (TUG) test time after exercise in both the SMT group and GE group (p<0.05). Also, a significant increase was seen in muscle activation of tibialis anterior muscle after exercise in the SMT group (p<0.05), but no such significant increase was seen in the GE group (p>0.05). Conclusion: These results suggest that sensorimotor training improves the balance in older adults and has a more positive effect on muscular strength and gait. Sensorimotor training provided a variance of training environment and COG exercise of the body is thought to be a more effective exercise program that improves balance and gait ability in older adults.