• 대한교통학회지
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• 제30권1호
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• pp.19-30
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• 2012

하루 동안 발생하는 교통수요는 대부분 특정 시간대에 집중됨으로써 수요 및 편익 산정에 어려움을 초래한다. 따라서 보다 신뢰성 높은 결과를 산출하기 위해서는 시간대별 특성을 고려할 필요가 있다. 이를 위한 첨두/비첨두의 1시간 통행량으로 환산하는 방법으로는 직관적 방법, 경험적 방법, 통계적 방법 등이 있다. 본 연구에서는 통계적 방법의 일환인 혼합군집분석 기법을 적용하여 첨두/비첨두/심야시간에 대한 지속시간과 집중률을 산정한다. 한국건설기술연구원이 제공하는 2009년 전국 24시간 수시교통량 자료를 이용하였으며, 차종별 특성을 살펴보기 위해 승용차, 트럭, 전차종 등으로 나누어 분석을 실시하였다. 분석결과의 검증을 위해 한국도로공사의 TCS 통행시간 자료를 이용하였다. 검증결과 본 연구결과가 타 연구에 비해 비첨두/심야 시간에는 오차율이 낮으며, 첨두시에는 통행거리가 멀어질수록 오차율이 높아지는 결과를 보였다. 본 연구결과는 임의성을 배제할 수 있으며, 첨두율 추정치에 대한 신뢰성 검증을 수행할 수 있어 보다 안정적인 방법론이라 평가할 수 있을 것이다. 본 연구의 결과가 향후 교통수요 분석의 신뢰성 향상에 일조할 수 있기를 기대한다.

• 대한토목학회논문집
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• 제33권4호
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• pp.1581-1589
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• 2013

본 연구는 역사의 승객수요 패턴과 토지이용 특성을 반영하여 도시철도역 승객의 첨두시간 집중률을 산정하는 방법론을 제시하는 것을 목적으로 한다. 이를 위하여 요인분석과 군집분석을 기반으로 서울시 도시철도 역사를 3개의 그룹으로 분류한다. 각 그룹별로 이용수요의 첨두시간 집중률과 함께 도시철도 승객수요 패턴과 역사의 토지이용과 관련한 5가지 변수와 4가지 변수를 각각 산출한다. 통계 검정을 기반으로, 이 변수들 중 일평균 승객수와 업무 LQ지수가 역사의 그룹을 구분하는 기준으로 선정된다. 두 변수들을 활용하여 새로 건설되는 도시철도역의 첨두시간 집중률을 추정하기 위한 그룹할당과정을 제시한다. 13개의 도시철도역 자료를 이용한 검증을 통해 본 연구의 방법론은 현재 이용되는 지침에 비하여 더 적은 오차를 산출할 수 있다는 것을 확인하였다. 본 연구의 방법론은 신규 철도역사의 효율적인 건설 및 운영계획 수립에 기여할 수 있을 것으로 사료된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.17-23
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• 2001

The aim of tins study is to compare the travel time of urban railway with that of arterial roads in the Seoul metropolitan area, focusing on the five main railways and arterials - Ilsan, Bundang, Kwacheon, Kyoungwon, and Kyoungin in order to make suggestions about improvements of railways. We found that the travel times of railways and arterials are about one and a half hour and an hour respectively, also the ratio of railway travel time to arterial travel time is 1.34 at peak and 1.58 at off-peak. We conclude that the competitiveness of the railroads is lower than the arterials. It will be necessary that we research the ways to improve the service of railways and investment ranking among the five main railways.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권3호
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• pp.874-890
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• 2021

With the widespread deployment of the fifth-generation (5G) communication networks, various real-time applications are rapidly increasing and generating massive traffic on backhaul network environments. In this scenario, network congestion will occur when the communication and computation resources exceed the maximum available capacity, which severely degrades the network performance. To alleviate this problem, this paper proposed an intelligent resource allocation (IRA) to integrate with the extant resource adjustment (ERA) approach mainly based on the convergence of support vector machine (SVM) algorithm, software-defined networking (SDN), and mobile edge computing (MEC) paradigms. The proposed scheme acquires predictable schedules to adapt the downlink (DL) transmission towards off-peak hour intervals as a predominant priority. Accordingly, the peak hour bandwidth resources for serving real-time uplink (UL) transmission enlarge its capacity for a variety of mission-critical applications. Furthermore, to advance and boost gateway computation resources, MEC servers are implemented and integrated with the proposed scheme in this study. In the conclusive simulation results, the performance evaluation analyzes and compares the proposed scheme with the conventional approach over a variety of QoS metrics including network delay, jitter, packet drop ratio, packet delivery ratio, and throughput.

• Safety and Health at Work
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• 제8권2호
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• pp.212-219
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• 2017

Background: Low back pain (LBP) is a major problem for office workers. Individuals adopting poor postures during prolonged sitting have a considerably increased risk of experiencing LBP. This study aimed to investigate seat pressure distribution characteristics, i.e., average pressure, peak pressure ratio, frequency of postural shift, and body perceived discomfort (BPD), during 1 hour of sitting among office workers with and without chronic LBP. Methods: Forty-six participants (chronic LBP = 23, control = 23) typed a standardized text passage at a computer work station for an hour. A seat pressure mat device was used to collect the seat pressure distribution data. Body discomfort was assessed using the Body Perceived Discomfort scale. Results: Office workers with chronic LBP sat significantly more asymmetrically than their healthy counterparts. During 1-hour sitting, all workers appeared to assume slumped sitting postures after 20 minutes of sitting. Healthy workers had significantly more frequent postural shifts than chronic LBP workers during prolonged sitting. Conclusion: Different sitting characteristics between healthy and chronic LBP participants during 1 hour of sitting were found, including symmetry of sitting posture and frequency of postural shift. Further research should examine the roles of these sitting characteristics on the development of LBP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1605-1608
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• 2004

Single phase $CuInS_2$ thin film with a highest diffraction peak (112) at a diffraction angle ($2{\theta}$) of 27.7$^{\circ}$ was well made by SEL method at annealing temperature of 250 $^{\circ}C$ and annealing hour of 60 min in vacuum of $10^{-3}$ Torr or in S ambience for an hour. And the peak of diffraction intensity at miller index (112) of $CuInS_2$ thin film annealed in S ambience was shown a little higher about 11 % than in only vacuum. Single phase $CuInS_2$ thin films were appeared from 0.85 to 1.26 of Cu/In composition ratio and sulfur composition ratios of $CuInS_2$ thin films fabricated in S ambience were all over 50 atom%. Also when Cu/In composition ratio was 1.03, $CuInS_2$ thin film with chalcopyrite structure had the highest XRD peak (112). And lattice constant a and grain size of the thin film in S ambience were appeared a little larger than those in only vacuum. The largest lattice constant of a and grain size of $CuInS_2$ thin film in S ambience was 5.63 ${\AA}$ and 1.2 ${\mu}$m respectively. And the films in S ambience were all p-conduction type with resistivities of around $10^{-1}{\Omega}cm$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.379-380
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• 2005

Single phase $CuInS_2$ thin film with a highest diffraction peak (112) at a diffraction angle ($2\Theta$) of $27.7^{\circ}$ was well made by SEL method at annealing temperature of $250^{\circ}C$ and annealing hour of 60 min in vacuum of $10^{-3}$ Torr or in S ambience for an hour. And the peak of diffraction intensity at miller index (112) of $CuInS_2$ thin film annealed in S ambience was shown a little higher about 11 % than in only vacuum. Single phase $CuInS_2$ thin films were appeared from 0.85 to 1.26 of Cu/In composition ratio and sulfur composition ratios of $CuInS_2$ thin films fabricated in S ambience were all over 50 atom%. Also when $CuInS_2$ composition ratio was 1.03, $CuInS_2$ thin film with chalcopyrite structure had the highest XRD peak (112). The largest lattice constant of a and grain size of $CuInS_2$ thin film in S ambience was 5.63 ${\AA}$ and 1.2 ${\mu}m$ respectively. And the films in S ambience were all p-conduction type with resistivities of around $10^{-1}{\Omega}cm$.

• Journal of Pharmaceutical Investigation
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• 제33권1호
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• pp.51-53
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• 2003

This study was conducted to compare the bioavailability of a generic product of Sinil Atenolol Tablets (Sinil Pharmaceutical Co., Ltd., Korea) with the innovator product, $Tenormin^{\circledR}$ Tablets in 20 healthy Korean volunteers. The volunteers received a single 50 mg dose of each atenolol formulation according to a randomized, two-way crossover design. Plasma samples were obtained over a 24-hour interval, and atenolol concentrations were determined by HPLC with a fluorescence detector. From the plasma atenolol concentration vs time curves, the following parameters were compared: area under the plasma concentration-time curve (AUC), peak plasma concentration $(C_{max})$, time to reach peak plasma concentration $(T_{max})$, and terminal first order elimination half-life $(t_{1/2})$. No statistically significant difference was obtained between the $T_{max}$ values, and the logarithmic transformed AUC and $C_{max}$ values of the two products. The 90% confidence for the ratio of the logarithmically transformed AUC and $C_{max}$ values of Sinil Atenolol Tablets over those of $Tenormin^{\circledR}$ Tablets were calculated to be between 0.99 and 1.07, and 1.04 and 1.16, respectively; both were within the bioequivalence limit of 0.80-1.25. The mean of $T_{max}$ in $Tenormin^{\circledR}$ Tablet group was 3.68 hour, and that in Sinil Atenolol Tablet group was 3.65 hour. The values of $t_{1/2}$ between the two products were found comparable, and the mean $t_{1/2}$ values of $Tenormin^{\circledR}$ Tablets and Sinil Atenolol Tablets were 5.9 and 6.0 hour, respectively. Based on these results, it was concluded that Sinil Atenolol Tablets were comparable to $Tenormin^{\circledR}$ Tablets in both the rate and extent of absorption, indicating that Sinil Atenolol Tablets were bioequivalent to the reference product, $Tenormin^{\circledR}$ Tablets

• Biomolecules & Therapeutics
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• 제15권3호
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• pp.187-191
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• 2007

This study was conducted to compare the bioavailability of two brands of atenolol (50 mg) tablets, which are a generic product of $Ditent^{\circledR}$ (Daewon Pharmaceutical Co., Ltd., Korea) and an innovator product $Tenormin^{\circledR}$ (Hyundai Pharm. Ind. Co., Ltd., Korea), in 20 healthy Korean male volunteers. The volunteers received a single 50 mg dose of each atenolol formulation according to a randomized, two-way cross-over design. The washout period between treatments was 1 week. Plasma samples were obtained over a 24-hour interval, and atenolol concentrations were determined by HPLC with a fluorescence detector. From the plasma atenolol concentration vs. time curves, the following parameters were compared: area under the plasma concentration-time curve ($AUC_{0-24}$), peak plasma concentration ($C_{max}$), time to reach peak plasma concentration ($T_{max}$), and terminal first order elimination half-life ($t_{1/2}$). No statistically significant difference was obtained between the $T_{max}$ values, and the logarithmic transformed $AUC_{0-24}$ and $C_{max}$ values of the two products. The 90% confidence interval for the ratio of the logarithmically transformed AUC and $C_{max}$ values of $Ditent^{\circledR}$ over those of $Tenormin^{\circledR}$ were calculated to be between 0.85 and 1.04, and 0.89 and 1.07, respectively; both were within the bioequivalence limit of 0.80-1.25. The mean of $T_{max}$ in $Tenormin^{\circledR}$ group was 3.1 hour, and that in Ditent$^{\circledR}$ group was 3.2 hour. The values of $t_{1/2}$ between the two products were found comparable, and the mean values were 5.2 hour in the both products. Based on these results, it was concluded that $Ditent^{\circledR}$ was comparable to $Tenormin^{\circledR}$ in both the rate and extent of absorption, indicating that $Ditent^{\circledR}$ was bioequivalent to the reference product, $Tenormin^{\circledR}$.

• Wind and Structures
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• 제7권3호
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• pp.145-158
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• 2004

The evaluation of the accumulation of permanent set for inelastic structures due to wind action is important in establishing a criterion to select a reduced design wind load and in incorporating the beneficial ductile behaviour in wind engineering. A parametric study of the accumulation of the permanent set as well as the ductility demand for bilinear single-degree-of-freedom (SDOF) systems is presented in the present study. The dynamic analysis of the inelastic SDOF system is carried out using the method of Newmark for artificially generated time history of wind speed. Simulation results indicate that the mean of the normalized damage rate is highly dependent on the natural frequency of vibration. This mean value is relatively insensitive to the damping ratio if the damping ratio is larger than 5%. The scatter associated with the accumulation of the permanent set is very significant. The consideration of the postyield stiffness can significantly reduce the accumulation of the permanent set if the ratio of the yield strength to the expected peak response is small. The results also show that the ductility demand due to the wind action over a period of one hour for flexible structures can be much less than that for rigid structures or structures with larger damping ratio if the SDOF systems are designed with a reduced peak response caused by the fluctuating wind.