• Journal of Radiation Protection and Research
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• v.34 no.2
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• pp.65-68
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• 2009

Metal-semiconductor contact is very important for the operating property of semiconductor detector. $Cd_{0.96}$ $Zn_{0.04}$ Te semiconductor crystal was grown with Bridgman method, and the crystal was cut and polished. EPMA (Electron Probe Micro Analyzer) and ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis were done to obtain the chemical composition and impurity of the crystal. Metal contact was deposited with thermal evaporator on both sides of the crystal. Detectors with Au/CZT/Au and In/CZT/Au structure were made, and I-V curve and the energy spectrum were measured with the detectors. It could be seen that the detector with the In/CZT/Au structure has superior property than the detector with Au/CZT/Au structure when the crystal resistivity was low. However, the metal contact structure effect becomes low when the crystal resistivity was high.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.145-148
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• 2000

In contrast to the $\pi$ -conjugated polymers which typically absorb light only in the visible spectral region, the $\sigma$-conjugated polymers can be used as efficient material absorbing light in the UV region. In this work, the electronic and optical properties of I$_2$-doped $\sigma$ -conjugated poly (methyl-phenylsilylene) (PMPSi) polymer were investigated. DC conductivity up to 1.2$\times$10$^{-4}$ S/cm was obtained by I$_2$-doping. In UV/Vis absorbance spectrum, a new peak was observed near 370 nm, which was explained by polaron model. The photoluminescence (PL) intensity decreased with increasing degree of I$_2$-doping, and the Infrared (IR) spectrum analysis revealed that the dopants are not directly coupled to the polymer, but effect motions of the methyl and phenyl groups.

• International Journal of Advanced Culture Technology
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• v.6 no.4
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• pp.80-86
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• 2018

The intervention of Autism Spectrum Disorder (ASD) is limited research focus on the effect of occupational-based intervention. This study sought to determine the effect of occupational-based intervention of chopstick skills for children with ASD. This study included a total of 3 children with ASD.Using single-subject study design, a changing criterion design and ABC design were implemented. The participants' behavior was observed and recorded throughout each session. In this study, the results were analyzed through visual graphs. The amount of food that was moved using the chopsticks was gradually increased. The results show that all participants significantly improved in their ability to use chopsticks in each intervention session. In addition, Assessment of Motor and Process Skills (AMPS) improved the generalization. According to the AMPS, both the overall motor and process skills increased from baseline an average of 0.7 logit. The results of this study showed occupational-based intervention on chopsticks skill to be effective in acquisition and generalization of chopstick skill in children with ASD.

• Journal of Radiation Protection and Research
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• v.43 no.4
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• pp.137-142
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• 2018

Background: Gamma-ray detectors having a thin window of a material with low atomic number can increase the true coincidence summing effects for radionuclides emitting X-rays or gamma-rays. This effect can make efficiency calibration or spectrum analysis more complicated. In this study, a Cu shield was tested as an X-ray filter to neglect the true coincidence summing effect by X-rays and gamma-rays in gamma-ray spectrometry, in order to simplify gamma-ray energy spectrum analysis. Materials and Methods: A Cu shield was designed and applied to an n-type high-purity germanium detector having an $X-{\gamma}$ summing effect during efficiency calibration. This was tested using a commercial, certified mixed gamma-ray source. The feasibility of a Cu shield was evaluated by comparing efficiency calibration results with and without the shield. Results and Discussion: In this study, the thickness of a Cu shield needed to avoid true coincidence summing effects due to $X-{\gamma}$ was tested and determined to be 1 mm, considering the detection efficiency desired for higher energy. As a result, the accuracy of the detection efficiency calibration was improved by more than 13% by reducing $X-{\gamma}$ summing. Conclusion: The $X-{\gamma}$ summing effect should be considered, along with ${\gamma}-{\gamma}$ summing, when a detection efficiency calibration is implemented and appropriate shielding material can be useful for simplifying analysis of the gamma-ray energy spectra.

• ETRI Journal
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• v.44 no.4
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• pp.543-559
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• 2022

To determine a suitable waveform for Internet of Things (IoT) transmission over low-Earth orbit (LEO) satellites, this paper reports the results of a performance comparison between chirp spread spectrum (CSS)-based LoRa and direct sequence spread spectrum (DSSS)-based Ingenu. The performance of both waveforms was measured in terms of the packet error rate, throughput, and packet loss rate, considering the Doppler effect caused by the high speed of LEO satellites and the interference among multiple terminals. Simulation results indicate that the DSSS scheme is more suitable than the CSS scheme for high-traffic IoT services because of its robustness against interference among multiple terminals. However, the CSS scheme is more suitable than the DSSS scheme for high-mobility IoT services because of its robustness against the Doppler effect. We discuss various solutions, such as the preprocessing of Doppler effect and avoidance of packet collision, to enhance the performance of the DSSS and CSS schemes. The simulation results of the proposed solution show that the enhanced DSSS scheme can be a proper waveform in IoT transmission over LEO satellites for both the high-traffic and high-mobility services.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.205-206
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• 2006

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.413-414
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• 2018

• Therapeutic Science for Rehabilitation
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• v.10 no.4
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• pp.7-24
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• 2021

Objective : This study examined the characteristics of the literature involving a single-subject research design among positive behavior support intervention studies to improve problem behavior in children with autism spectrum disorders and assess the quality level. Methods : This is a literature study, and the targets of analysis were nine single-subject research papers published between 2011 and 2020. The subject papers were analyzed by dividing them into general characteristics and the qualitative levels according to the content of the research method. Results : Analysis of analyzing the contents of the study showed that the subjects were preschool and elementary school-age children at the same ratio. Furthermore, the study design involved mostly the middle and multiple baseline designs among the behaviors. All papers presented social validity, intervention fidelity, and observer reliability. Problem behaviors included self-injury and aggression behaviors, disturbing behaviors, and seat break-away behaviors, while the most dependent variables were measured through partial interval recording. As a result of confirming the intervention effect, the effect was confirmed in intervention, maintenance, and generalization. All analysis studies showed high-quality levels. Conclusion : This study confirmed the content and qualitative level of the thesis that applied the single-subject research design among positive behavior support intervention studies for problem behaviors of children with autism spectrum disorders. Positive behavior support intervention, an evidence-based intervention for children with autism spectrum disorders, was confirmed an effective intervention for autism spectrum disorders.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.1-4
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• 1989

The Alexandrite (Cr:BeAl2O4) laser is one of the promising tunable (vibronic) solid state laser developed recently in the near infrared region (700~800nm) of the spectrum. The thermal lensing effect of rod may effect stable mode osicillation of the solid state laser. A design procedure of the Alexandrite laser resonator considering rod thermal lensing effect and misaligment sensitivity of the resonator will be presented.

• Therapeutic Science for Rehabilitation
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• v.7 no.4
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• pp.57-66
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• 2018

Objective: The purpose of this study is to investigate the effect of interactive metronome (IM) training on attention among children on the autistic spectrum. Methods: This is a single case study, using ABA design, of one child with autism spectrum disorder (ASD) who had attentional difficulties. A total of 20 sessions were conducted: 3 baseline sessions (A), 14 intervention sessions (B), and 3 follow-up baseline sessions (A'). During the intervention period (B), IM training was performed. Inattention and attention activities were measured as the dependent variables in all three phases (A, B, and A'). Results: Compared to baseline, the subject's inattention decreased in the IM training mediation period, and the performance of activities requiring attention also improved. The intervention effect was maintained even during the follow-up baseline period. Conclusion: The results of this study suggest that IM training positively influences attention among children with ASD with attention deficit symptoms. Further, it provides the clinical basis of IM training as an intervention for children with ASD.