• Composites Research
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• v.27 no.2
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• pp.59-65
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• 2014

Most of energy are obtained from oil, coal, and natural gas, most likely, fossil fuel which is limited throughout the world. Recently, high crude oil price, climate change, oil depletion, etc. are main reason to get attention to non-fossil energy including renewable energy in the world. In this study, we studied analysis and design of structure system composed of pultruded fiber reinforced polymer composite (PFRP) which has many advantages such as high specific strength and stiffness, high corrosion resistance and chemical resistance. For the design and construction of floating-type structure, PFRP structural members may be the first choice. Design of tracking-type floating PV generation structure was performed by using the results of the finite element analysis. The structure is fabricated and installed on the water surface. Before the installation of the structure, safety related problems associated with installation and operation are investigated using the finite element simulation and it was found that the structure is safe enough to resist externally applied loads.

• Journal of KSNVE
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• v.8 no.6
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• pp.1166-1171
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• 1998

The influences of the coupler consisting of stiffness and mass between neighboring two spans on mode localization are studied theoretically, and the results are confirmed by numerical examples. The mass of the coupler makes a structure sensitive to mode localization especially in higher modes while the stiffness does in all modes. A new type of delocalization phenomenon is observed for the first time in some modes for which mode localization does not occur or is very weak although structural disturbances are severe. A spring-mass system consisting of two substructures and a coupler connecting them is considered in the part of analytical study. As example structures for numerical analysis. simply supported continuous two-span beams with a coupler having a rotational stiffness and a mass moment of inertia on the mid support are considered.

• Information Systems Review
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• v.12 no.3
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• pp.159-175
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• 2010

Although many studies have analyzed and identified the importance of intrinsic motivation in the acceptance of information technology (IT), especially hedonic systems such as online game and online shopping, the acceptance of programming languages such as Java were not studied in a view of intrinsic motivations. The objective of this study was to investigate the effects of intrinsic motivation on the acceptance of programming language by the longitudinal analysis. In the service of the objective, we suggested the research model which included both intrinsic and extrinsic motivations and longitudinally extended by belief updating theory. For the validation of this model, the university students who participated Java class were surveyed twice, and the suggested research were analyzed by partial least square (PLS). In result, most of the suggested hypotheses were supported.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.24 no.4
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• pp.5-22
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• 2013

Institutional repository has been regarded as core facilities of research libraries to realize open access by collecting, preserving, distributing of intellectual asset what institution has created. In our country, many universities and research institutions are trying to introduce institutional repository system. But almost universities not only take the negative attitude to manage properly, but also never give basic training to staff members who take over institutional repository job. This study brightens up the current status of Korean training system and compares the British and Japanese cases what shows diverse advanced managing cases. Furthermore, by putting together demands of hands-on workers, suggest direction of future institutional repository staff training system. First, institutional repository staff training system has to suggest strategies to induce strong support from institution. Second, it has to give not only courses about content collecting and registering, but also practical training. Finally, the program for enhancing system management technology has to be provided, and the place where technical staffs can share their system information mutually has to be provided.

• Magazine of the Korea Concrete Institute
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• v.2 no.4
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• pp.91-98
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• 1990

Joints are provided in cement concrete pavements to control transverse and longitudinal cracking that occur due to restrained deformations caused by moisture and temperature variations in the slab. But the constuction of joints reduces the load-carrying capacity of the pavement at the joints, and pavements have been deteriorated by cracks at the slab edges along the joints due to traffic loads. Therefore, it is important to analyze the behavior of joints accurately in the design of cement concrete pavements. In this study, the mechanical behavior of cement concrete pavement slabs is analyzed by the plate-finite element model, and Winkler foundation model is adopted to analyze the subgrades. The load transfer mechan¬ism of joints are composed of dowel action, aggregate interlocking, and tied-key action, and the analytical pro¬gram is developed using these joint models. Using this numerical model as an analysis tool, the effects of joint parameters on the behavior of pavements are investigated.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.349-353
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• 2008

In this paper, the EM wave absorber was designed and fabricated for preventing Reader Interference of RFID communication system in UHF band We fabricated several samples in different composition ratios of Amorphous and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability due to composition ratio. The mixing ratio of Amorphous and CPE was searched as 80 : 20 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has a thickness of 4 mm and absorption ability was over 20 dB in frequency range of $860\;MHz{\sim}960\;MHz$. Therefore, it was confirmed that the developed absorber can be used for suppressing RFID reader interference in UHF band.

• Journal of Korean Society of Steel Construction
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• v.18 no.3
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• pp.361-371
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• 2006

In recent years, to overcome drawbacks related to the aplicati on of classical structural optimization algorithms, various drift design methods based on factores of member displacement participation factors have been developed to size members if they satisfy stiffness criteria. In particular, a resizing algorithm based on dynamic displacement participation factors from the response spectrum analysis has been applied in the drift design of steel structures subjec ted to seismic lateral forces. In this aproach, active members are selected for displacement control based on the displacement participation fa ve members may be taken out and added to the active members for the drift control. The resizing algorithm can be practically and effectively applied to drift design of high-rise buildings however, the inelastic behavior o f the resizing algorithm has not ben evaluated yet. To develop the resizing algorithm considering the performance of nonlinearity as well a s elastic stifness, the evaluation model of resizing algorithm s is developed and aplied to the examples of moment-resisting steel frame, which is one of the simplest structural systems. The inelastic behavior of moment-resisting steel frame designed by the resizing algorithm is also discussed.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.132-143
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• 2017

While working in an industrial environment which requires extended periods of upright posture; workers tend to develop muscle fatigue due to the constant load on lower-limb muscles. In addition, when working while bending knees; muscle fatigue of lower back and hamstrings is increased due to the abnormal posture. This can lead to damage of muscles, induce musculoskeletal disorders, and reduce long-term working efficiency. Recent medical studies have shown that long-term working in an upright posture can induce musculoskeletal disorders such as foot fatigue, edema, pain and varicose veins. Likewise, medical and rehabilitation expenses have grown due to the increase in musculoskeletal conditions suffered by workers. For this problem, we aim to develop a device that can reduce the physical fatigue on the lower limbs by supporting the weight of workers during the extended periods of upright and bending postures in the industrial environments. In this paper, we have designed and manufactured a wearable weight support system; with a user intention algorithm that the users can maintain various postures. For validation of the developed system, we measured the muscle activity of the users wearing the system with EMG sensors.

• Journal of the Korean Society for information Management
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• v.22 no.3 s.57
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• pp.261-287
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• 2005

The purpose of this paper is to explore the ways to improve the performance of SVM (Support Vector Machines) text classifier using inter-document similarities. SVMs are powerful machine learning systems, which are considered as the state-of-the-art technique for automatic document classification. In this paper text categorization via SVMs approach based on feature representation with document vectors is suggested. In this approach, document vectors instead of index terms are used as features, and vector similarities instead of term weights are used as feature values. Experiments show that SVM classifier with document vector features can improve the document classification performance. For the sake of run-time efficiency, two methods are developed: One is to select document vector features, and the other is to use category centroid vector features instead. Experiments on these two methods show that we can get improved performance with small vector feature set than the performance of conventional methods with index term features.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.82-87
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• 2003

This research is concerned with ground experiments for satellite solar array deployment as well as the validation of theoretical modeling technique presented in the previous paper. We carried out the experiments on the strain energy hinge with stopper to investigate he buckling characteristics of the SEH, which affects the shape and the speed of the solar array deployment. The moment-angle diagram obtained from the experiments was later combined with the theoretical deployment model. This paper also presents the details of the ground experiments performed at the Korea Aerospace Research Institute(KARI) . It was found that the ground experimental results were in good agreement with the theoretical predictions thus validating the dynamic modeling technique.