• Ecology and Resilient Infrastructure
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• v.1 no.2
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• pp.49-60
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• 2014

Fish assemblages play an integral role in stream ecosystem and are influenced by stream environmental conditions and habitat disturbances. Fish community structures and habitat parameters of U.S. EPA rapid bio-assessment protocol were surveyed to investigate the effect of stream environment and habitat disturbance on fish communities at 13 study sites in the Gapyeong Stream, a typical gravel-bed stream. Principal component analysis (PCA) based on data from habitat assessment at each study site indicated that the study sites were differentiated by habitat parameters such as embeddedness, velocity/depth regime and sediment deposition, which were related with bed slope. A total of 46 species belonging to 12 families were collected in the Gapyeong Stream. A dominant species was Zacco koreanus, subdominant species was Z. platypus. Hierarchical cluster analysis based on species abundance classified fish communities into the three main groups along the stream longitudinal change. Non-metric multidimensional scaling (NMDS) portrayed that fish community structures were related to major habitat parameters, i.e., epifaunal substrate/available cover, embeddedness, velocity/depth regime, sediment deposition, channel alternation and frequency of riffles. These results suggested that fish community structures were primary affected by the longitudinal environmental changes, and those were modified by habitat disturbance in the Gapyeong Stream, a gravel-bed stream.

• Journal of Korean society of Dental Hygiene
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• v.5 no.2
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• pp.171-184
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• 2005

In order to investigate correlation between mother's dental ca re for her children and their dental caries, this study was conducted wi th the dental examination record of 365 children who showed the same number of questionnaires with those examined for dental conditions and questionnaires written by mothers among children between three and six years of age and their mothers in Yeoncheon, Gyeonggi province in June 2004 to estimate frequency and percentage of general properties of subjects and mother's oral health care behaviors for her children by research items, to carry out cross-tabulation analysis and correlation analysis following Chi-square distribution for the presence of dental caries in deciduous teeth and oral health care behaviors, and to use decision tree analysis among data mining techniques for those factors associated with the presence of dental caries in deciduous teeth, and drew the following conclusions. 1. For mother's oral health care behaviors and attitudes for her children, 225 mothers(61.6%) confirmed their children's teeth-brushing; 278(76.2%) used no fluorine; and 286(78.6%) observed their children's teeth, 322 mothers(88.2%) instructed their children in teeth-brushing while 268 (73.4%) provided dental care, 232 mothers(63.7%) treated their children's cavity; 290(79.4%) believed that their children had good dental conditions; and 294(80.5%) answered that they began to provide their children with dental care in deciduous teeth. 2. As for the presence of dental caries in deciduous teeth and dental health care behaviors, there were statistically significant differences in employment, confirmation after teeth-brushing, teeth observation, instruction in time for teeth-brushing, use of fluorine, cavity treatment, time for dental care, and perception of dental conditions(p<0.05). 3. As for correlation between dental caries in deciduous teeth and oral health care behaviors, mothers who worked, who believed that their children didn't have good dental condition, and who thought that it was necessary to begin to provide dental care in permanent teeth were found to get their children to suffer from dental caries in deciduous teeth. Besides, those who failed to confirm teeth-brushing, who used no fluorine, and who failed to observe teeth and gave no instruction in time for teeth-brushing were shown to get their children to suffer from dental caries in deciduous teeth. 4. Variables to determine the presence of dental caries in deciduous teeth were classified by cavity treatment, mother's employment, time for dental care, and observation of children's teeth. The first node to determine the presence of dental caries in deciduous teeth was found to be cavity treatment; the next criteria for classification after cavity treatment were shown to be mother's employment and time for dental care. In case of children with no cavity, they were found to be mother's employment and teeth observation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.712-722
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• 2018

This paper conducts parametric studies on flapping wing design, one of the most important design parameters of insect-mimicking aerial vehicles. Experimental study on wing shape was done through comparison and analysis of thrust, pitching moment, power consumption, and thrust-to-power ratio. A two-axis balance and hall sensor measure force and moment, and flapping frequency, respectively. Wing configuration is biplane configuration which can develop clap and fling effect. A reference wing shape is a simplified dragonfly's wing and studies on aspect ratio and wing area were implemented. As a result, thrust, pitching moment, and power consumption tend to increase as aspect ratio and area increase. Also, it is found that the flapping mechanism was not normally operated when the main wing has an aspect ratio or area more than each certain value. Finally, the wing shape is determined by comparing thrust-to-power ratio of all wings satisfying the required minimum thrust. However, the stability is not secured due to moment generated by disaccord between thrust line and center of gravity. To cope with this, aerodynamic dampers are used at the top and bottom of the fuselage; then, indoor flight test was attempted for indirect performance verification of the parametric study of the main wing.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.297-305
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• 1998

This study used in vivo intracellular recording in rat hippocampus to evaluate the effect of lidocaine and MK-801 on the membrane properties and the synaptic responses of individual neurons to electrical stimulation of the commissural pathway. Cells in control group typically fired in a tonic discharge mode with an average firing frequency of $2.4{\pm}0.9$ Hz. Neuron in MK-801 treated group (0.2 mg/kg, i.p.) had an average input resistance of $3.28{\pm}5.7\;M{\Omega}$ and a membrane time constant of $7.4{\pm}1.8$ ms. These neurons exhibited $2.4{\pm}0.2$ ms spike durations, which were similar to the average spike duration recorded in the neurons of the control group. Slightly less than half of these neurons were firing spontaneously with an average discharge rate of $2.4{\pm}1.1$ Hz. The average peak amplitude of the AHP following the spikes in these groups was $7.4{\pm}0.6$ mV with respect to the resting membrane potential. Cells in MK-801 and lidocaine treated group (5 mg/kg, i.c.v.) had an average input resistance of $3.45{\pm}6.0\;M{\Omega}$ and an average time constant of $8.0{\pm}1.4$ ms. The cells were firing spontaneously at an average discharge rate of $0.6{\pm}0.4$ Hz. Upon depolarization of the membrane by 0.8 nA for 400 ms, all of the tested cells exhibited accommodation of spike discharge. The most common synaptic response contained an EPSP followed by early-IPSP and late-IPSP. Analysis of the voltage dependence revealed that the early-IPSP and late-IPSP were putative $Cl^--and\;K^+-dependent$, respectively. Systemic injection of the NMDA receptor blocker, MK-801, did not block synaptic responses to the stimulation of the commissural pathway. No significant modifications of EPSP, early-IPSP, or late-IPSP components were detected in the MK-801 and/or lidocaine treated group. These results suggest that MK-801 and lidocaine manifest their CNS effects through firing pattern of hippocampal pyramidal cells and neural network pattern by changing the synaptic efficacy and cellular membrane properties.

• 대한공업교육학회지
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• v.33 no.1
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• pp.191-212
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• 2008

The purpose of this study was to show how to organize small groups on the project method class in technical high school. The subjects of this study were two classes including 40 second-year students (20 students in each class) of architecture design course in D technical high school located in Taejeon metropolitan city. The method of this study was to investigate the ego-state by the ego-gram practicing Transactional Analysis. Total 10 small groups were organized. Each group had 4 members. And the same quality of egostate small group was organized by the 4 students who have high score on NP and AC. The different in kind small group was organized by the 4 students, each of whom has NP leading, A leading, FC leading and AC leading score. After the target small group was video- taped, students' verbal interaction was written into transcripts. Their individual states were analysed by the frame of verbal interaction. The result of this study was that the same quality of TAOK small group had more active interaction(110 times) than different in kind small group(87 times). The frequency of complementary transaction was also higher plenty in the same quality of TAOK small group.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.67-73
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• 2016

Recently, wireless power transmission has attracted much interest and is the subject of much research in industry and academia. As its name implies, it is a technology which involves transferring power without wires. This paper presents the design of an ICT-based wireless power transmission system. The proposed system consists of a wireless transceiver unit and high-efficiency coil unit, which can increase both the transmission efficiency and the effective power distance. In particular, the wireless transceiver unit was designed to work with the ICT technique to enable real-time remote monitoring. Also, studies were done relating to the effect of reducing the standby power. The optimal frequency of IGBT devices used in industrial wireless power systems of 20[KHz] was utilized. The values of $23.9[{\mu}H]$ and $2.64[{\mu}F]$ were selected for L and C, respectively, through many field experiments designed to optimize the system design. In addition, an output current controlling algorithm was developed for the purpose of reducing the standby power. The results presented in this paper represent a 75[%] to 85[%] higher power transmission efficiency with a 10[%] increase in the effective power transmission distance compared with the existing systems. As a result, the proposed system exhibits a lower standby power and maintenance costs. Also, the designed wireless transceiver unit facilitates fault detection by means of user acquired data with the development of the ICT applied program.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6126-6133
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• 2014

This study examined the effects of a simulation-based core skill program regarding emergency care on the knowledge, problem solving process and self-esteem of health related department students. A quasi-experimental non-equivalent control group pre-post test design was used. A total of 46 students, 23 students for the experimental group and 23 students for the control group, were enrolled in this study. The simulation-based core skill program included lectures, skill training, team-based practice, simulation and debriefing. This was implemented in the experimental group for 3 weeks in May, 2013. The data was analyzed using the frequency, ratio, Chi-square, and t-test by the SPSS/Win 18.0. The experimental group, who had a simulation-based core skill program, showed significantly higher clinical knowledge, problem solving process and self-esteem compared to the control group who had a traditional education. A clinical simulation-based core skill program was verified to be an effective teaching method to improve on the clinical knowledge, problem solving process and self-esteem of health-related department students.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1109-1117
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• 2014

We study free vibration analysis of sigmoid functionally graded materials(S-FGM) nano-scale plates, using a nonlocal elasticity theory of Eringen in this paper. This theory has ability to capture the both small scale effects and sigmoid function in terms of the volume fraction of the constituents for material properties through the plate thickness. Numerical solutions of S-FGM nano-scale plate are presented using this theory to illustrate the effect of nonlocal theory on natural frequency of the S-FGM nano-scale plates. The relations between nonlocal and local theories are discussed by numerical results. Further, effects of (i) power law index (ii) nonlocal parameters, (iii) elastic modulus ratio and (iv) thickness and aspect ratios on nondimensional frequencies are investigated. In order to validate the present solutions, the reference solutions are compared and discussed. The results of S-FGM nano-scale plates using the nonlocal theory may be the benchmark test for the free vibration analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.601-611
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• 2016

The research, development and use of seismic isolation systems have been increasing with the gradual development of structure safety assurance methods for earthquakes. The High Damping Rubber Bearing (HDRB), one type of seismic isolation system, is a Laminated Rubber Bearing using special High Damping Rubber. However, as its damping function is slightly lower than that of the Lead Rubber Bearing, a similar seismic isolation system, its utilization has not been high. However, the HDRB has a superior damping force to the Natural Rubber Bearing, which has similar materials and shapes, and the existing Lead Rubber Bearing has a maleficence problem in that it contains lead. Thus, studies on HDRBs that do not use lead have increased. In this study, a test targeting the HDRB was done to examine its various dependence properties, such as its compressive stress, frequency and repeated loading. To evaluate the HDRB's seismic performance in response to several earthquake waves, the shaking table test was performed and the results analyzed. The test used the downscaled bridge model and the HDRB was divided into seismic and non-seismic isolation. Consequently, when the HDRB was applied, the damping effect was higher in the non-seismic case. However, its responses on weak foundations, such as in Mexico City, represented increased shapes. Thus, its seismic isolator.

• Korean Security Journal
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• no.29
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• pp.59-86
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• 2011

The purpose of this study is to investigate the relationship between organizational culture, organizational trust and organizational performance of special guard organization. This study had selected special guards from 4 different private guard companies which are in Seoul area on March 2011. Using Judgement Sampling, 161 samples were drawn for the use of final analysis. Questionnaire used in this study was consisted of the total 42 question, and executed frequency analysis, factor analysis, reliability analysis, correlation analysis, multiple regression analysis, path analysis by SPSSWIN 18.0. The Cronbach's ${\alpha}$ value which represents the reliability of the survey came out to be over .592. The results are following: First, the organizational culture of special guard organization affects organizational trust. That is, when a developmental, reasonable, consensual and hierarchical culture is activated, cognitive emotional and behavioral trust is increased. Second, organizational culture of special guard organization affects organizational performance. That is, when a reasonable and consensual culture is activated, job-satisfaction becomes higher. On the other hand, when a developmental, reasonable and hierarchical culture is activated, organizational flow becomes higher. Third, organizational trust of special guard organization affects organizational performance. That is, when a cognitive emotional and behavioral trust works highly, job-satisfaction and organizational flow is increased. Fourth, Special security organization's organizational culture affects as a result in organization result. As well as organizational culture exerts direct influence on organization outcome, I exert effect that is indirect in organization outcome through action trust which is low rank factor of organization trust.