• Korean Journal of Child Studies
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• v.29 no.1
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• pp.189-205
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• 2008

A group theraplay program for improving social competence of children in group homes was composed of 24 sessions. The researcher and a therapist accessed 5 children living in a group home and conducted one session each week for 6 months from May to September. Before the application of the program, a pre-test was conducted using evaluation measures of attachment stability, social competence, and children's behavioral problems. A post-test was performed after the end of the program and a follow-up test was carried out to determine the long term effects of the program. Results showed that the group theraplay program improved attachment stability and social competence of children in group homes and was effective in changing problem behaviors.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.8 s.251
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• pp.756-763
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• 2006

PEMFC has several technical problems such as water management, long term stability and performance degradation as. PEMFC has been studied not only to solve water management, but also to generate power in stable manner to system by using a hybrid system with auxiliary energy storage device. The purpose of this study is to couple PEMFC with supercapacitor to make a hybrid system and to design and test control strategies for stable power generation in case of changing output power. The polarization curve and dynamic behaviors while changing power were investigated to find out characteristics of PEMFC stack. A DC/DC converter was fabricated in order to increase fuel cell and supercapacitor voltage and to charge supercapacitor. We found that the operation strategy 2 was recommended to the system because of solving water management problem and increasing the dynamic behavior.

• Journal of the Korean Regional Science Association
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• v.15 no.3
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• pp.33-51
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• 1999

After the 1997 currency crisis, the real estate prices had been rapidly dropped and the deregulation in the Korean real estate merket has been performed. It is analyzed whether these transactions caused a structural change in real estate market, or not. The Pettitt test shows there exists a turing point in real estate prices in 1998. It is found that the degrees of co-movement between the change in real estate prices and real GDP growth rate are increased. Consequently, the factor, represented as real GDP growth rate, determining the market fundamental of real estate prices will effect on the behavioral pattern and the real estate prices in the long run. While the factors determining the portfolio selection behaviors, such as interest rate and stock prices, will cause short-term variations.

• Journal of Astronomy and Space Sciences
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• v.5 no.1
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• pp.57-72
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• 1988

The long-term observational properties of the photometric behaviors of the short period(p=0.48 day) eclipsing binary system XY UMa are discussed. They are based on the UBV observatins, which were carried out by Geyer in the yaers 1955-1961, 1968, 1975-1984. Light curves of XY UMa revealed very large changes not only between consecutive observing nights, but also from season to season. Between 1955 and 1984, the mean system brightness increased about 30% during this time interfvals, meanwhile, the orbital period of this system was constant whithin 1.6% of its period. The colour index curve shows similar variations like the light curve but with a phase offset oscillation around the time instants of the primary minama. Observational evidence for photospheric and chromospheric activities on the XY Uma are also discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.21-29
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• 2013

The functional behaviors of human standing postural control were investigated when they were exposed to long-term horizontal vibration in the sagittal plane. For complexity of human postural control, a useful alternative method that has been based on a black-box approach was taken; that is, where the feedback mechanism was lumped into a single element. A motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced continuous anterior/posterior (AP) motion. The data were analyzed both in the time and frequency domain. The cross-correlation and coherency functions were estimated. Subjects behaved as a non-rigid pendulum with a mass and a spring throughout the whole period of the platform motion, as consistent with the plan chosen for this study.

• Journal of Conservation Science
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• v.36 no.4
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• pp.244-254
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• 2020

This study investigates prehistoric human subsistence and pottery use on the Korean peninsula through the organic residue analysis of archaeological potsherds. Ancient human subsistence is one of the core topics in Korean archaeology. However, due to the high acidity of sediments, which prevents the long-term preservation of organic remains, archaeologists have been short of critical information on how these early prehistoric dwellers lived. Ceramic vessels can contain well-preserved lipids originating from past culinary practices. For a better understanding of human subsistence on the prehistoric Korean peninsula, food-processing behaviors were reconstructed by analyzing ancient lipids extracted from a pottery matrix. The potsherd samples used in the analysis in this paper were collected from major prehistoric habitation sites. The results show that subsistence strategies differed according to both location and time period and reveal how organic residue analysis can contribute to a better understanding of prehistoric human subsistence strategies.

• Biomolecules & Therapeutics
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• v.19 no.1
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• pp.9-20
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• 2011

Repeated administration of addictive drugs causes cellular and molecular changes believed to be the mechanism of pro-addictive behaviors. Neuroadaptations also take place with repeated administration of amphetamine, methylphenidate and atomoxetine, drugs for Attention Deficit Hyperactivity Disorders (ADHD), and it is speculated that these changes may serve as markers to demonstrate the dependence liability of these therapies. In this review, we enumerate the neuroadaptive changes in molecules associated with neuronal signaling and plasticity, as well as neuronal morphology wrought by repeated administration of ADHD medications. We provide the current perspective on the dependence liability of these therapies, and also suggest of some factors that need to be considered in future investigations, so that what is drawn from animal studies would be better consolidated with those known clinically.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.19-30
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• 2017

Austenitic Stainless Steels (ASSs) are widely used as structural materials in the pressurized water reactors (PWRs) because of their superior mechanical properties and corrosion resistance. However, it is well known that ASSs are susceptible to the environmental assisted cracking (EAC) such as environmental assisted fatigue (EAF) during the long term operation. There have been extensive tests and researches to understand the extent and the mechanisms of environmental effects. In this paper, the world-wide EAF test results of ASSs are introduced including those of Korean test programs. The suggested EAF mechanisms of ASSs are also discussed. Finally, the areas of further research to resolve the issue of EAF are suggested.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.9
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• pp.533-539
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• 2003

Reinforcement learning (RL) has been widely used as a learning mechanism of an artificial life system. However, RL usually suffers from slow convergence to the optimum state-action sequence or a sequence of stimulus-response (SR) behaviors, and may not correctly work in non-Markov processes. In this paper, first, to cope with slow-convergence problem, if some state-action pairs are considered as disturbance for optimum sequence, then they no to be eliminated in long-term memory (LTM), where such disturbances are found by a shortest path-finding algorithm. This process is shown to let the system get an enhanced learning speed. Second, to partly solve a non-Markov problem, if a stimulus is frequently met in a searching-process, then the stimulus will be classified as a sequential percept for a non-Markov hidden state. And thus, a correct behavior for a non-Markov hidden state can be learned as in a Markov environment. To show the validity of our proposed learning technologies, several simulation result j will be illustrated.

• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.527-534
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• 2020

This study aims to monitor the displacement of the bridges using Stanford Method for Persistent Scatterers (StaMPS) time-series Persistent Scatterer Interferometric Synthetic Aperture Radar analysis. For case study bridges: Kimdaejung bridge and Deokyang bridge, we acquired 60 and 33 Cosmo-Skymed Synthetic Aperture Radar (SAR) data over the Mokpo region and Yeosu region, respectively from 2013 to 2019. With single-look interferograms, we estimated the long-term time-series displacements over the bridges. The time-series displacements were estimated as -8.8 mm/year and -1.34 mm/year at the mid-span over the selected bridges: Kimdaejung and Deokyang bridge, respectively. This time-series displacement provides reliable and high spatial resolution information to monitor the structural behavior of the bridge for preventing structural behaviors.