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Optimal transmission policies for MOT in T-DMB
Donghwan Lee,Jihoon Choi,Kyunghwi Kim,Wonjun Lee,Choonhwa Lee IEEE 2007 IEEE communications letters Vol.11 No.12
<P>The Multimedia Object Transfer (MOT) protocol in Terrestrial Digital Multimedia Broadcasting (T-DMB) systems inherently does not facilitate return paths in data transmission and therefore additional policies are required to envision further efficient reliable media broadcasting. This letter proposes novel optimal transmission policies for MOT standard definition in T-DMB. The proposed broadcasting policies drastically enhance the capability of conventional MOT protocol.</P>
Donghwan Park(Donghwan Park),Kang-Seong Lee(Kang-Seong Lee) 물리치료재활과학회 2024 Physical therapy rehabilitation science Vol.13 No.1
Objective: The objective of this study was to investigate the effect of the thoracic mobility exercise program on pain, proprioception, and static balance ability in patients with non-specific chronic low back pain. Design: Randomized controlled trial design. Methods: Thirty patients with non-specific chronic low back pain participated in this study. The participants were randomized into the thoracic mobility exercise group (n=15) and the lumbar stabilization exercise group (n=15). Both groups received traditional physical therapy for 30 minutes per session. In addition, the thoracic mobility exercise group and the lumbar stabilization exercise group each exercise 3 times a week for 6 weeks. All participants were measured visual analog scale, proprioception test, and static balance ability before and after the intervention. Results: After 6 weeks of interventions, the thoracic mobility exercise group showed greater improvement in visual analog scale, proprioception test, and static balance ability than the LSE group (p<0.05). Further, the thoracic mobility exercise group had significant Enhancements in all measured variables compared to the baselinetest (p<0.05). However, the lumbar stabilization exercise group had significant improvement only visual analog scale, and static balance ability compared to the baselinetest (p<0.05). Conclusions: Our investigation demonstrates that the thoracic mobility exercise is an effective intervention method for improving pain, proprioception, and static balance ability in patients with non-specific chronic low back pain.
Lee, Jong-Gun,Lee, Jong-Hyuk,An, Seongpil,Yoon, Joshua Yeosong,Choi, Jae-Wook,Kang, Min Gu,Lee, Jeong In,Song, Hee-eun,Al-Deyab, Salem S.,James, Scott C.,Kang, Yoonmook,Kim, Donghwan,Yoon, Sam S.,Lee, Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.695 No.-
<P><B>Abstract</B></P> <P>Supersonic cold sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. Choice of carrier gas (nitrogen and air) and effects of particle size and impact velocity on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. The carrier gas had no discernable effect on electrode properties while increased particle sizes slightly decreased electrode specific resistivities. Impact velocity had the most pronounced influence on electrode electrical properties. Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. Adhesion strength was measured with a STAB-TEST instrument and found sufficient for all measured electrodes. The electrodes were further characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and auger electron spectroscopy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Supersonically sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. </LI> <LI> Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. </LI> <LI> Effects of impact conditions on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. </LI> <LI> Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
차량 실내 소음 주파수 특성 변경이 운전성 평가에 미치는 영향
안동환(Donghwan Ahn),이동현(Donghyun Lee),김영관(Younggwan Kim),위효성(Hyoseong Wi),이진우(Jinwoo Lee),박진일(Jinil Park),이종화(Jonghwa Lee),김범수(Beomsoo Kim),이석재(Seogjae Lee) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Vehicle performance is improving day by day. So drivers want to higher quality of drivability, which include acceleration performance, interior noise, vibrations and etc. In particular, the vehicle interior noise which is a major factor in the evaluation drivability is important factor. In this study, According to the frequency of vehicle interior noise, vehicle interior noise were analyzed which based on sound pressure level. On the basis of this analysis, the interior noise was changed through sound equipment, such as a microphone and equalizer. This interior noise was evaluated by drivers and identified a correlation between subject’s responses and changing of the frequency. As a result of this research, frequency bands and sound pressure levels which affect evaluation drivability were presented to meet the needs of consumers about acceleration, noise and vibration.
Dynamics and Mechanism of Flame Retardants in Polymer Matrixes: Experiment and Simulation
Yoon, Donghwan,Jung, Hyun Tae,Kwon, Gyemin,Yoon, Yeoeun,Lee, Minsoo,Bae, Imhyuck,Joo, Beom Jun,Kim, Mansuk,Lee, Sun Ae,Lee, Jihye,Lee, Yeonhee,Cho, Eunseog,Shin, Kwanwoo,Sung, Bong June American Chemical Society 2013 The journal of physical chemistry. B, Condensed ma Vol.117 No.28
<P>We investigate the dynamics and the mechanism of flame retardants in polycarbonate matrixes to explore for a way of designing efficient and environment-friendly flame retardants. The high phosphorus content of organic phosphates has been considered as a requirement for efficient flame retardants. We show, however, that one can enhance the efficiency of flame retardants even with a relatively low phosphorus content by tuning the dynamics and the intermolecular interactions of flame retardants. This would enable one to design bulkier flame retardants that should be less volatile and less harmful in indoor environments. UL94 flammability tests indicate that even though the phosphorus content of 2,4-di-<I>tert</I>-butylphenyl diphenyl phosphate (DDP) is much smaller with two bulky tertiary butyl groups than that of triphenyl phosphate (TPP), DDP should be as efficient of a flame retardant as TPP, which is a widely used flame retardant. On the other hand, the 2-<I>tert</I>-butylphenyl diphenyl phosphate (2-<I>t</I>BuDP), with a lower phosphorus content than TPP but with a greater phosphorus content than DDP, is less efficient as a flame retardant than both DDP and TPP. Dynamic secondary ion mass spectrometry and molecular dynamics simulations reveal that the diffusion of DDP is slower by an order of magnitude at low temperature than that of TPP but becomes comparable to that of TPP at the ignition temperature. This implies that DDP should be much less volatile than TPP at low temperature, which is confirmed by thermogravimetric analysis. We also find from Fourier transform infrared spectroscopy that Fries rearrangement and char formation are suppressed more by DDP than by TPP. The low volatility and the suppressed char formation of DDP suggest that the enhanced flame retardancy of DDP should be attributed to its slow diffusivity at room temperature and yet sufficiently high diffusivity at high temperature.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-28/jp400114x/production/images/medium/jp-2013-00114x_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp400114x'>ACS Electronic Supporting Info</A></P>