• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.191-194
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• 2007

Objective : Homeless patients probably have epidemiologic features that are different from those of general population. However, there have been no published articles about clinical characteristics of neurosurgical homeless patients. The authors tried to assess the clinical characteristics and treatment outcome of homeless neurosurgical patients. Methods : We retrospectively reviewed the medical records and radiological films of 76 homeless patients and 72 non-homeless patients following head trauma who were admitted to our neurosurgical department between June 2001 and June 2005. We compared two groups of the patients with the demographics, the clinical and laboratory characteristics. Also, 3D-day mortality was determined according to Glasgow Coma Scale (GCS) score. Results : Age of homeless patients was younger than that of non-homeless patients. Homeless patients had previous craniotomy evidences in skull x-rays more frequently (10.5% vs. 1.4%). Acute subdural hematoma was the most common type of head injury in the two groups. Moderate and severe head injury, based on GCS score on admission was more frequent in homeless patients (64% vs. 39%). Fifty percent of homeless patients underwent operation for traumatic head injury. However, 3D-day mortality according to GCS score was not significantly higher in homeless patients. Conclusion : Most homeless neurological patients were relatively young men. Also, moderate or severe brain injuries were observed more frequently. However, mortality rate of homeless patients in neurosurgical field is not significantly higher in the present study.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.2
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• pp.891-895
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• 2015

We investigated the effects of a Virtual reality(VR) program on the proprioception and instability of functional ankle instability(FAI) patients. Among the 20s old individuals who lived in Republic of Korea; 20 people were selected through a public participation process. The 20 participants were then randomly divided into two groups, one of strength exercise(n=10) and one of balance exercise(n=10). Of the patients who had experienced an ankle sprain in the past and currently felt ankle instability, those who recorded 24 points or less on the Cumberland ankle instability tool(CAIT) were determined to have FAI. We selected the strength exercise and balance exercise in the Nintendo Wii Fit Plus as a VR program. The subjects used the program on the Wii Balance Board three times per week for 20 minutes and total 10-minute warm-up and down for four weeks. Proprioception and CAIT of the balance exercise group were improved significantly after the exercise compared to before the exercise(p<.05). Authors recommend that the balance exercise in the VR program be used as an aid for physical therapeutic intervention.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.405-410
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• 1994

The purpose of this paper is to present the details of design procedure of a nonlinear regulator by Riemannian geometric approach and to applied it to the case of a double-effect evaporator. A nonlinear geometric model is proposed on a direct sum space of a state vector and a control vector as well as in the previous parers by the authors. The geometric model is derived by replacing the orthogonal straight coordinate axes of a linear system on the direct sum space with the curvilinear coordinate axes. The integral manifold of the geometric model becomes homeomorphic to that of fictitious linear system. For the geometric model a nonlinear regulator with a performance index is designed renewedly by the procedure of optimization. The construction method of the curvilinear coordinate axes on which the nonlinear system behaves as a linear system is discussed. To apply the above regulator theory to double-effect evaporators especially to the pilot plant at the University of Alberta, a suitable nonlinear model is determined by the plant dynamics. The optimal control law is derived through the calculation of the homeomorphism. As a result it is confirmed that the regulator is effective and superior to that of the conventional control.

• Wind and Structures
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• v.8 no.2
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• pp.89-106
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• 2005

For estimating the vortex excited vibrations of overhead transmission lines, the Energy Balance Principle (EBP) is well established for spans damped near the ends. Although it involves radical simplifications, the method is known to give useful estimates of the maximum vibration levels. For very long spans, there often is the need for a large number of in-span fittings, such as in-span Stockbridge dampers, aircraft warning spheres etc. This adds complexity to the problem and makes the energy balance principle in its original form unsuitable. In this paper, a modified version of EBP is described taking into account in-span damping and in particular also aircraft warning spheres. In the first step the complex transcendental eigenvalue problem is solved for the conductor with in-span fittings. With the thus determined complex eigenvalues and eigenfunctions a modified energy balance principle is then used for scaling the amplitudes of vibrations at each resonance frequency. Bending strains are then estimated at the critical points of the conductor. The approach has been used by the authors for studying the influence of in-span Stockbridge dampers and aircraft warning spheres; and for optimizing their positions in the span. The modeling of the aircraft warning sphere is also described in some detail.

• Journal of Korean Elementary Science Education
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• v.25 no.3
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• pp.271-280
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• 2006

In this paper, an Online Scientific Inquiry Learning System was developed with the aim of improving student's scientific literacy and scientific inquiry ability. It was determined that there should be 4 distinct principles applicable to the design of the Learning system. First, it should enrich learner's motivation. Second, it should provide students with the chance for reflecting on the inquiry process. Third, it should emphasize multi-dimensional forms of interaction. Fourth, students should be able to create new information through it. The server system including the database, equation editor, reporting tool, search engine were all utilized for developing the learning system. In addition, the authors produced 24 web-based projects which were guided inquiry activities in which various inquiry abilities (reasoning, prediction, experiment design) could be developed. An Online Scientific Inquiry Learning System is not the only program which could be utilized in improving scientific inquiry abilities, but at the very least, such a system can serve as the prototype for developing an online learning system.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.17 no.1
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• pp.1-20
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• 2006

The family life cycle is a useful indicator of consumer behavior, as well as the family life cycle concept utilizes a combination of demographic and socioeconomic variables that best explains the changes in the construct of the family. The family decision-making research has frequently examined role relationship between husband and wife across stages and sub-decisions. The objective of this research is to measure children and parents' perceptions of the influence of the decision-making process for a family dining-out experience, and to determined the customers' choice behavior of restaurants according to isolated factors underlying the important attributes of the restaurants, and finally authors applied a market segmentation approach by capturing customers' preference of restaurant attributes in family dining-out situation and to investigated influence of the family decision making for family dining out in family life cycle. For practitioner, marketing implications are provided and recommendations for future research are also discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1102-1105
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• 2003

Energy distribution function for electrons in $SF_6$-Ar mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range $30{\sim}300[Td]$ by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2(%) and 0.5(%) $SF_6$-Ar mixtures were measured by time-of-flight(TOF) method, The results show that the deduced electron drift velocities, Electrons Drift Velocities for a rang of E/N values. As a consequence, it was known that the spatial growth rates and the dielectric behaviors in $SF_6$-Ar mixtures are strongly dependent on the addition rate of $SF_6$ gas but the transport coefficients of electrons are insensitive to the addition rate of $SF_6$ gas. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.39-39
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• 2010

The authors have an extensive study of photoluminescences for Zn-polar and O-polar faces of single-crystalline ZnO bulks. In the photoluminescence (PL) spectra at 10 K, Zn-polar and O-polar faces show a common emission feature: neutral donor-bound excitons and their longitudinal-optical (LO) phonon replicas are strong, and free excitons are very weak. However, in the PL spectra at room temperature (RT), Zn-polar and O-polar faces show extremely different emission characteristics: the emission intensity of Zn-polar face is 30 times larger than that of O-polar face, and the band edge of Zn-polar face is 33 meV red-shifted from that of O-polar face. The temperature dependence of photoluminescence indicates that the PL spectra at RT are closely associated with free excitons and their phonon-assisted annihilation processes. As a result, it is found that the RT PL spectra of Zn-polar face is dominated by the first-order LO phonon replica of A free excitons, while that of O-polar face is determined by A free excitons. This is ascribed that Zn-polar face has larger exciton-phonon coupling strength than O-polar face.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.675-681
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• 1989

As an adaptive control function generator, the CMAC (Cerebellar Model Arithmetic or Articulated Controller) based learning control has drawn a great attention to realize a rather robust real-time manipulator control under the various uncertainties. There remain, however, inherent problems to be solved in the CMAC application to robot motion control or perception of sensory information. To apply the CMAC to the various unmodeled or modeled systems more efficiently, It is necessary to analyze the effects of the CMAC control parameters an the trained net. Although the CMAC control parameters such as size of the quantizing block, learning gain, input offset, and ranges of input variables play a key role in the learning performance and system memory requirement, these have not been fully investigated yet. These parameters should be determined, of course, considering the shape of the desired function to be trained and learning algorithms applied. In this paper, the interrelation of these parameters with learning performance is investigated under the basic learning schemes presented by authors. Since an analytic approach only seems to be very difficult and even impossible for this purpose, various simulations have been performed with prespecified functions and their results were analyzed. A general step following design guide was set up according to the various simulation results.

• Journal of Mechanical Science and Technology
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• v.16 no.5
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• pp.599-608
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• 2002

Finite element analysis for the stress intensity factor (SIF) at the skin/stiffener structure with inclined central crack repaired by composite stiffened panels is developed. A numerical investigation was conducted to characterize the fracture behavior and crack growth behavior at the inclined crack. In order to investigate the crack growth direction, maximum tangential stress (MTS) criterion are used. Also, this paper is to study the performance of the effective bonded composite patch repair of a plate containing an inclined central through-crack. The main objective of this research is the validation of the inclined crack patching design. In this paper, the reduction of stress intensity factors at the crack-tip and prediction of crack growth direction are determined to evaluate the effects of various non-dimensional design parameter including; composite patch thickness and stiffener distance. We report the results of finite element analysis on the stiffener locations and crack slant angles and discuss them in this paper. The research on cracked structure subjected to mixed mode loading is accomplished and concludes that more work using a different approaches is necessary. The authors hope the present study will aid those who are responsible for the repair of damaged aircraft structures and also provide general repair guidelines.