• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.331-340
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• 2009

This study evaluates the relationship between cone tip resistance ($q_c$) and small-strain shear modulus ($G_{max}$) of cemented sand. For this purpose, a series of miniature cone penetration and bender element tests are performed in calibration chamber specimens with various gypsum contents. Experimental results show that both $q_c$ and $G_{max}$ of sand increase with increasing cementation level as well as relative density and vertical confining stress. However, the relative density and vertical confining stress has more significant influence on $G_{max}$ and $q_c$ of uncemented sand than those of cemented sand. It is observed that the $G_{max}/q_c$ ratio of cemented sand decreases with increasing relative density. This result means that state variables have more affect on $q_c$ than $G_{max}$ of cemented sand. Test results also show that the effect of vertical stress on $G_{max}-q_c$ relation is reduced by cementation effect.

• 한국통신학회논문지
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• 제36권4A호
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• pp.380-387
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• 2011

While mobile IPTV services are supported through the mobile WiMAX networks, there must need some guaranteed bandwidth for the IPTV services especially if IPTV and non-IPTV services are simultaneously supported by the mobile WiMAX networks. The quality of an IPTV service definitely depends on the allocated bandwidth for that channel. However, due to the high quality IPTV services and to support of huge non-IPTV traffic over mobile WiMAX networks, it is not possible to guarantee the sufficient amount of the limited mobile WiMAX bandwidth for the mobile IPTV services every time. A Service Level Agreement (SLA) between the mobile IPTV service provider and mobile WiMAX network operator to reserve sufficient bandwidth for the IPTV calls can increase the satisfaction level of the mobile IPTV users. In this paper, we propose a SLA negotiation procedure for mobile IPTV users over mobile WiMAX networks. The Bandwidth Broker controls the allocated bandwidth for IPTV and non-IPTV users. The proposed dynamically reserved bandwidth for the IPTV services increases the IPTV user's satisfaction level. The simulation results state that, our proposed scheme is able to provide better user satisfaction level for the IPTV users.

• 한국통신학회논문지
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• 제34권2A호
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• pp.113-123
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• 2009

최근에 무선 메쉬 네트워크는 기존의 무선 네트워크의 단점을 해결하기 위한 차세대 네트워크 기술로서 많은 연구가 이루어지고 있다. 특히, mobile WiMAX 기반의 무선 메쉬 네트워크는 여러 가지 측면에서 많은 장점을 가지고 있어 더욱 주목받고 있다. 이 논문에서 우리는 mobile WiMAX 기반의 무선 메쉬 네트워크를 위한 2계층 핸드오버 방안을 제안한다. Mobile WiMAX의 2계층 핸드오버 방안은 무선 메쉬 네트워크의 특성을 고려하지 않기 때문에, mobile WiMAX 기반의 무선 메쉬 네트워크에서 많은 핸드오버 실패를 유발한다. 제안하는 핸드오버 방안은 기존의 핸드오버 방안보다 핸드오버 시에 더 적은 지연시간을 달성하면서 데이터 손실이 발생하지 않는다. 시뮬레이션을 통해서 제안한 핸드오버 방안이 핸드오버 시에 발생할 수 있는 핸드오버 지연 문제와 데이터 손실 문제를 개선할 수 있음을 보였다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2007년도 추계학술대회 논문집
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• pp.67-68
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• 2007

• 대한치과의사협회지
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• 제22권3호통권178호
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• pp.243-255
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• 1984

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권1호
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• pp.24-33
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• 2012

This paper describes a multi-mode LDPC decoder which supports 19 block lengths and 6 code rates of Quasi-Cyclic LDPC code for Mobile WiMAX system. To achieve an efficient implementation of 114 operation modes, some design optimizations are considered including block-serial layered decoding scheme, a memory reduction technique based on the min-sum decoding algorithm and a novel method for generating the cyclic shift values of parity check matrix. From fixed-point simulations, decoding performance and optimal hardware parameters are analyzed. The designed LDPC decoder is verified by FPGA implementation, and synthesized with a $0.18-{\mu}m$ CMOS cell library. It has 380,000 gates and 52,992 bits RAM, and the estimated throughput is about 164 ~ 222 Mbps at 56 MHz@1.8 V.

• 한국전기전자재료학회논문지
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• 제16권12호
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• pp.1097-1102
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• 2003

In this paper, we used only PR as etching mask, while it used usually Cr/AU as etching mask, and in order to fabricate a photosensor has the increased sensitivity, we investigated on the sensitivity of general type and p-i-n type diode. we designed microchannel size width max 10um, min 5um depth max 10um, reservoir size max 100um, min 2mm. Fabrication of microfluidic devices in glass substrate by glass wet etching methods and glass to glass fusion bonding. The p-i-n diode has higher sensitivity than photodiode, Considering these results, we fabricated p-i-n diodes on the high resistive(4㏀$.$cm) wafer into rectangle and finger pattern and compared internal resistance of each pattern. The internal resistance of pin diode can be decreased by the application of finger pattern has parallel resistance structure from 571Ω to 393Ω.

• The Korean Journal of Physiology and Pharmacology
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• 제3권2호
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• pp.137-146
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• 1999

Interactions among dexamethasone, dehydroepiandrosterone (DHEA), lipopolysaccharide (LPS), and antimycin A on the glutamate uptake and the polyamine uptake were investigated in primary cultures of rat cerebral cortical astrocytes to examine the effects of dexamethasone and DHEA on the regulatory role of astrocytes in conditions of increased extracellular concentrations of glutamate or polyamines. 1. $[^3H]Glutamate$ uptake: LPS and antimycin A decreased $V_{max},$ but both drugs had little effect on $K_m.$ Dexamethasone also decreased basal $V_{max}$ without any significant effect on $K_m.$ And dexamethasone further decreased the antimycin A-induced decrease of $V_{max}.$ DHEA did not affect the kinetics of basal glutamate uptake and the change by LPS or antimycin A. 2. $[^{14}C]Putrescine$ uptake: LPS increased $V_{max},$ and antimycin A decreased $V_{max}.$ They showed little effect on $K_m.$ Dexamethasone decreased $V_{max}$ of basal uptake and further decreased the antimycin A-induced decrease of $V_{max},$ and also decreased $V_{max}$ to less than control in LPS-treated astrocytes. DHEA did not affect $K_m$ and the change of $V_{max}$ by LPS or antimycin A. 3. $[^{14}C]Spermine$ uptake: Antimycin A decreased $V_{max},$ and LPS might increase $V_{max}.\;K_m$ was little affected by the drugs. Dexamethasone decreased basal $V_{max}$ and might further decrease the antimycin A-induced decrease of $V_{max}.$ And dexamethasone also decreased $V_{max}$ to less than control in LPS-treated astrocytes. DHEA might increase basal $V_{max}$ and $V_{max}$ of LPS-treated astrocytes. 4. $V_{max}$ of glutamate uptake by astrocytes was increased by putrescine (1000 ${\mu}M$ & 2000 ${\mu}M$) and spermidine (200 ${\mu}M,$ 500 ${\mu}M$ & 2000 ${\mu}M$). Spermine, 200 ${\mu}M$ (and 100 ${\mu}M$), also increased $V_{max},$ but a higher dose of 2000 ${\mu}M$ decreased $V_{max}.\;K_m$ of glutamate uptake was not significantly changed by these polyamines, except that higher doses of spermine showed tendency to decrease $K_m$ of glutamate uptake. In astrocytes, dexamethasone inhibited the glutamate uptake and the polyamine uptake in normal or hypoxic conditions, and the polyamine uptake might be stimulated by LPS and DHEA. Polyamines could aid astrocytes to uptake glutamate.

• 운동영양학회지
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• 제24권2호
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• pp.30-37
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• 2020

[Purpose] The present study investigated the effect of endurance exercise with blood flow restriction (BFR) performed at either 25% maximal oxygen uptake (${\dot{V}}O_2$ max) or 40% ${\dot{V}}O_2$ max) on muscle oxygenation, energy metabolism, and endocrine responses. [Methods] Ten males were recruited in the present study. The subjects performed three trials: (1) endurance exercise at 40% ${\dot{V}}O_2$ max without BFR (NBFR40), (2) endurance exercise at 25% ${\dot{V}}O_2$ max with BFR (BFR25), and (3) endurance exercise at 40% ${\dot{V}}O_2$ max with BFR (BFR40). The exercises were performed for 15 min during which the pedaling frequency was set at 70 rpm. In BFR25 and BFR40, 2 min of pressure phase (equivalent to 160 mmHg) followed by 1 min of release phase were repeated five times (5 × 3 min) throughout 15 minutes of exercise. During exercise, muscle oxygenation and concentration of respiratory gases were measured. The blood samples were collected before exercise, immediately after 15 min of exercise, and at 15, 30, and 60 minutes after completion of exercise. [Results] Deoxygenated hemoglobin (deoxy-Hb) level during exercise was significantly higher with BFR25 and BFR40 than that with NBFR40. BFR40 showed significantly higher total-hemoglobin (total-Hb) than NBFR40 during 2 min of pressure phase. Moreover, exercise-induced lactate elevation and pH reduction were significantly augmented in BFR40, with concomitant increase in serum cortisol concentration after exercise. Carbohydrate (CHO) oxidation was significantly higher with BFR40 than that with NBFR40 and BFR25, whereas fat oxidation was lower with BFR40. [Conclusion] Deoxy-Hb and total Hb levels were significantly increased during 15 min of pedaling exercise in BFR25 and BFR40, indicating augmented local hypoxia and blood volume (blood perfusion) in the muscle. Moreover, low-and moderate-intensity exercise with BFR facilitated CHO oxidation.

• 한국컴퓨터정보학회논문지
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• 제17권11호
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• pp.189-196
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• 2012

본 논문은 동적 경제급전의 최적화 문제를 풀기 위해 교환 알고리즘을 제안하였다. 제안된 알고리즘은 첫 번째로, 발전단가 $C_i^{max}/P_i^{max}$가 비싼 발전기는 가동을 중지시키는 개념을 도입하여 총 요구량 $P_d$와 총 발전량 ${\Sigma}P_i$의 균형을 맞추었다. 다음으로 발전량을 $P_i=P_i{\pm}{\Delta}$, (${\Delta}$=1.0, 0.1, 0.01, 0.001)에 대해 $_{max}[F(P_i)-F(P_i-{\Delta})]$ > $_{min}[F(P_j+{\Delta})-F(P_j)]$, $i{\neq}j$이면 $P_i=P_i-{\Delta}$, $P_j=P_j+{\Delta}$로 발전량을 교환하는 방법을 적용하였다. 동적 경제급전 문제의 시험사례에 제안된 알고리즘을 적용한 결과 기존의 휴리스틱 알고리즘 최적화 발전비용을 크기 감소시켜 경제적인 이익을 극대화 시켰다.