• Journal of Engineering Education Research
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• v.13 no.1
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• pp.70-77
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• 2010

The purpose of this study was to verify the educational value of student portfolio and to give the direction of making student portfolio. Qualitative research method was used to accomplish objectives of the study. 9 students who were winner in competition of student portfolio in I University at Incheon Province were interviewed. Data were recorded, transcribed and analyzed. Most students started to make student portfolio by compulsory, but they realized that it was necessary to start student portfolio from the lower grades. They had difficulties in not having materials of activities and hesitated at the beginning of making student portfolio even though they got standard form from the university. Students recognized that making student portfolio was effective tool because it could enhance self-reflection, awareness of importance of record, preparation of future, obtaining of motivation for anonther activities, getting self-confidence, and improvement of writing skill.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.587-595
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• 1997

Experimental study on unsaturated flow in the soil is important to understand the characteristics of the water flow. Measurement of unsteady-state water movement using the traditional equipment (e.g. tensiometer) has a problem that requires relatively a long response time. In this study a quick measurement method of soil water flow using TDR is introduced. TDR consists of an electronic function generator which generates a squared wave, and an oscilloscope which catches the reflected wave. The wave is reflected where both the impedance of the transmission line and the propagation velocity are changed. The water content can be obtained from the travel time measured by means of TDR because the dielectric constant is affected by the change of soil water content. From the result of TDR calibration. TDR measurement error for the oven dried soil was found to be less than 3.5%. This supports that TDR is a viable technique to measure the unsteady-state water movement.

• Land and Housing Review
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• v.9 no.1
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• pp.19-28
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• 2018

The purpose of this study is to explore an implication for new perspectives and concrete approaches to Korean Land Banking by analyzing the role of the Land Bank and the Land Storage System in the formation of Chinese Land Market, Land Management, and City Management. Time scope of this research focused on Chinese reform and opening since 1978, when study of land bank began to be actively performed in China. Research targets were Land Bank and Land Storage System related to Chinese Land System, and this research targeted Chinese Land Storage System as research object, which seem to have similar tendency to Korean Land Banking System, after examining the concept of Land Bank and Land Storage System. As the research method, this research arranged the contents and changes of policy based on discussed research documents over Chinese Land Bank and Land Storage System till today since the foundation of the nation. Later, this research investigated the realistic reflection and in-depth investigation of the problems through the operational mechanism and concrete case study of Chinese Land Storage System, a similar policy to Korean land bank, the researchers will look into the reality reflected and will carry out a in-depth study of the problems. China has established its characteristic socialistic market economy system, partly adopting the concept of capitalism, supporting socialism. This way, the researcher considers that such socialistic economic factors with strong welfare aspects can be adopted also in Korea, where capitalistic market economy system is maintained, and be utilized as a new measure for development strategy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.566-572
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• 2011

The satellite communication is an important method for maritime communications. Binary offset carrier (BOC) signal is a promising candidate of next generation global navigation satellite systems (GNSS). Synchronization of BOC signal is one of the most important processes to demodulate BOC signal in GNSS. However, in maritime environment, the synchronization of BOC signal is suffered from the problem of side-peak of BOC autocorrelation function and multipath fading caused by the sea surface reflection. In this paper, we proposed a novel synchronization scheme which can eliminate side-peak perfectly and is robust in multipath channel. Simulation results show that the proposed scheme has better performance than conventional schemes in multipath channel.

• Journal of Oriental Neuropsychiatry
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• v.18 no.1
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• pp.37-61
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• 2007

Objective : By examining EEG status in Korean Traditional Medicine (KTM) from the viewpoint of 'form-qi theory(形氣論)', We wish to prepare for the fundamentals of applicability of KTM diagnoses to EEG. In addition, through reinterpretation of existing Western Medicine reports from the viewpoint of KTM, We tried to find out interrelationship between them. Method : In this paper, a methodology applicable to KTM diagnoses of EEG is presented from the EEG features in waveform characteristics, personalized diversity, and cognitive activity reflection. Results : Frequency bands are assigned to corresponding one of the eight trigrams in terms of yin/yang balance, which is analogous with EEG spectrum analysis mostly used in EEG quantification. The amplitude ratio of each EEG for each frequency band gives meaningful index numbers which can be used in EEG data interpretation, and every index number is named after the sixty four hexagrams. These approaches are adopted through both '4-band classification system and '6-band classification system', and applied to pre-existing reported EEG data obtained from normal adults. These analyses show that changes and distribution pattern in the index numbers are observed as a whole on both left-right line and front-back line connecting EEG measurement cephalic electrodes. And differences in distribution pattern of three index numbers deduced from '6-band classification system' are discussed according to constitution. Conclusion : The index numbers introduced here, which are the spectral power ratio for each EEG, are based on KTM yin/yang balance. These index numbers vary according to cephalic location, so its application in terms of traditional meridian theory is strongly expected. The index number distribution also shows different patterns according to constitution.

• Korean Journal of Health Education and Promotion
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• v.25 no.3
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• pp.95-109
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• 2008

Objectives: The study was conducted to investigate visual display terminal(VDT) and related risk factors in office workers. Method: The study subjects were 539 officers at 3 places of business in Gwangju. The data were collected by self-administered questionnaire between October 12 and October 17, 2007. and they agreed to participate in this study. The tool was developed by Moon, Jaedong(1991) for VDT syndrome. Data analysis by using SPSS/win 10.0 was performed with descriptive statistics, t-test and ANOVA. Results: The summary of results is as follows: 1) The mean score of total VDT syndrome was $1.17{\pm}.65$ of full score 4.00, which was lower than other research. 2) For relation between general characteristics and total VDT, sex (t=-5.777, p=.000), age (F=3.516, p=.015), satisfaction of job (F=9.540, p=.000), self-awareness of health (F=25.015, p=.000) had statistically significant difference. 3) For relation between behavioral work factors and total VDT, break time of work(t=-5.363, p=.000), eye movement during computer work(t=2.176, p=.031), wrist exercise during(t=2.337, p=.020), distance between monitor and eyes(F=3.682, p=.012) had statistically significant difference. 3) For relation between environmental work factors and total VDT, height of chair(F=8.801, p=.000), space under desk(F=4.244, p=.015), reflection of monitor(t=2.697, p=.008) had statistically significant difference. Conclusion: To prevent and relieve VDT syndrome and musculoskeletal disorders in office workers, it is important to teach good posture and stretching exercise during work.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.249-258
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• 2020

The purpose of this study provides multicultural adolescents' out of school career preparation experience. Seven multicultural adolescents out of school living in Seoul, Gyeonggido, Chungchungdo were selected for the in-depth interview. Data were collected from July to September, 2019. This research utilized Colaizzi's phenomenological method. The participants provided 14 themes on the essential structure of experience and 5 theme clusters. The final 14 themes were relationship with friends, speedy learning ability, fear of learning, generous character, no dreaming, enjoying hobby, influence of job, influence of mother, no concept of career, looking for mother language-related job, no managing time and health, material abundance, trying diet, burden about test. Based on this result, it is suggested to acknowledge importance of positive motive pursuit for career, various support giving power, positive attitude of career, self-reflection, road to go for career preparation.

• Journal of Korean Elementary Science Education
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• v.32 no.1
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• pp.104-112
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• 2013

We examined the strategies to stimulate the reflective thinking using science notebook for the improvement of problem solving ability which is one of the core skills for the future. The strategies we derived have four steps which are input, output, solving mission and reflection as my own mirror. We applied the strategies to the 6th grade class for autumn semester in order to examine the students learning process and the result. We could observe that students looked into their own learning and had a time to look back their activities in the class. We could also confirmed that science notebook would be effective to improve the problem solving as stimulating the reflective thinking. In addition, we could specify the strategy of using science notebook in the class. At a 'input' stage, students should be able to choose their own learning style as their preference and teacher need to give them proper feedback. Interaction with peers should be emphasized during the activities as 'question attack' and 'question defense' in 'output' stage and 'solving mission' stage. You should suggest the students various method to record their thought from looking back their classroom activities instead of mere writing. We also examine the students achievement from the students' notebook and Meta Cognitive Awareness test. As a result, students who had studied using science notebook showed statistically meaningful higher achievement than controlled students.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.2
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• pp.115-124
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• 2015

A methodology is proposed to estimate a trajectory of a flying target and its velocity using the time and frequency analysis of the acoustic signal. The measurement of sound emitted from a flying acoustic source with a microphone above a ground shall receive both direct and ground-reflected sound waves. For certain frequency contents, the destructive interference happens in received signal waveform reflected path lengths are in multiple integers of direct path length. This phenomenon is referred to as the acoustical mirror effect and it can be observed in a spectrogram plot. The spectrogram of acoustic measurement for a flying vehicle measurement shows several orders of destructive interference curves. The first or second order of curve is used to find the best approximate path by using nonlinear least-square method. Simulated acoustic signal is generated for the condition of known geometric of a sensor and a source in flight. The estimation based on cepstrogram analysis provides more accurate estimate than spectrogram.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.736-742
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• 2003

This paper presents the propagation path loss in a tunnel which is a kinds of underground environments. To predict propagation path loss more accurately, we choose a straight tunnel with rectangular cross-section. The simulated receiver powers that are using a hybrid waveguide model and a Ray-Tracing method, are compared with the measured ones as a function of distance between TX and RX antennas in tunnel. The attenuation value of regression analysis for measured power in the tunnel is 0.0238dB/m which is similar to the one of the EH1.2 mode, 0.0246dB/m in hybrid waveguide model. By comparing simulation with measurement in tunnels, it has been shown that the measured values are approximate to the simulated results of ray-tracing model. In the analysis of wide-band channel characteristics of the tunnel, the more the distance between TX and RX antennas in tunnel increases, RMS delay spread increases and coherence bandwidth decreases.