• 한국통신학회논문지
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• 제21권10호
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• pp.2586-2596
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• 1996

The handover area is the region where a call can be handled by the base stations in any of the adjacent cells, and handover duration time is viewed as the time an mobile station resides inthe handover area. In this paper, analytic model to estimate the distribution function(df) of the handover duration time is proposed. Based on the df of the handover duration time, the simulation and anlytic models for the First Come first Serve(FCFS) scheme are presented, and the simulation results for the Measurement Based Prioritization Scheme(MBPS) are compared with the analytic results of the FCFS handover scheme. Those results show that the MBPS scheme is seen to provide lower handover failures than FCFS queueing with slightly increasing the new call blocking probability.

• 한국도로학회논문집
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• 제14권1호
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• pp.85-94
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• 2012

교통사고 발생시점부터 사고처리가 완료된 시점까지를 돌발상황 지속시간(Incident Duration Time)이라고 정의하는데, 이를 단축시켜야만 교통사고 피해를 최소화할 수 있다. 본 연구는 고속도로 교통사고를 대상으로 돌발상황 지속시간에 영향을 주는 요인들을 찾아내기 위한 모형을 개발하였다. 모형은 모든 사고자료에 포함한 통합 모형(모형1)과 일반구간, 교량, 터널 등 교통사고 장소별로 구분하여 분석한 세부 모형(모형 2, 3, 4) 등 모두 4개의 모형을 구축하였다. 분석 결과, 교통사고가 발생한 장소에 따라 돌발상황 지속시간에 다른 영향을 주는 것으로 나타났으며, 현장 처리를 위한 작업차량 도착시간이 가장 민감한 요인으로 분석되었다. 또한 차-차 사고, 화물차에 의한 사고, 야간 사고, 주말 사고 등의 시사점 있는 요인들을 찾아냈다. 이러한 연구결과는 향후 교통사고 관리대책을 수립하는 데 있어 중요한 판단지표로 활용이 가능할 것으로 판단된다.

• 한국환경과학회지
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• 제9권3호
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• pp.193-199
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• 2000

This study is carried out the analysis of the runoff characteristics for the design of the interior drainage systems by SWMM in urbanization basin. The basin analyzed in this study is Bumuh-chun basin which is located in Susung-gu of Taegu city. Huff method is used for rainfall distribution analysis. The optimal rainfall duration in Bumuh-chun basin is analyzed as about 90 minutes decided from comparison of arrival time and critical duration. Flood flow variation pattern is proposed through the comparison of the results of peak flow and peak time analyzed by SWMM about pre-urbanization and post-urbanization of Bumuh-chun basin. It is known that the variation of arrival time caused by the rapid increase of pavement rate in the upper area shows about 20∼25 minutes faster than pre- urbanization. Therefore, the management of surface water for design of water supply and drainage, and channel alteration has to considered the variation of geological factors according to urbanization.

• Journal of Construction Engineering and Project Management
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• 제4권4호
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• pp.33-40
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• 2014

Maximizing the profitability and minimizing the duration of construction projects in extreme weather regions is a challenging objective that is essential for project success. An optimization model is presented herein for the time-profit trade-off analysis of construction projects under extreme weather conditions. The model generates optimal/near optimal schedules that maximize profit and minimize the duration of construction projects in extreme weather regions. The computations in the model are organized into: (1) a scheduling module that develops practical schedules for construction projects, (2) a profit module that computes project costs (direct, indirect, and total) and project profit, and (3) a multi-objective module that determines optimal/near optimal trade-offs between project duration and profit. One example is used to show the impact of extreme weather on construction time and profit. Another example is used to show the model's ability to generate optimal trade-offs between the time and profit of construction projects under extreme weather conditions.

• 말소리와 음성과학
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• 제4권2호
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• pp.61-70
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• 2012

The current study observes the durational interaction of tautosyllabic consonants and vowels in the word-initial position of English and Korean child-directed speech (CDS). The effect of phonological laryngeal contrasts in stops on the following vowel duration, and the effect of the intrinsic vowel duration on the release duration of preceding stops in addition to the acoustic realization of the contrastive segments are explored in different prosodic contexts - phrase-initial/medial, focal accented/non-focused - in a marked speech style of CDS. A trade-off relationship between Voice Onset Time (VOT), as consonant release duration, and voicing phonation time, as vowel duration, reported from adult-to-adult speech, and patterns of durational variability are investigated in CDS of two languages with different linguistic rhythms, under systematically controlled prosodic contexts. Speech data were collected from four native English mothers and four native Korean mothers who were talking to their one-word staged infants. In addition to the acoustic measurements, the transformed delta measure is employed as a variability index of individual tokens. Results confirm the durational correlation between prevocalic consonants and following vowels. The interaction is revealed in a compensatory pattern such as longer VOTs followed by shorter vowel durations in both languages. An asymmetry is found in CV interaction in that the effect of consonant on vowel duration is greater than the VOT differences induced by the vowel. Prosodic effects are found such that the acoustic difference is enhanced between the contrastive segments under focal accent, supporting the paradigmatic strengthening effect. Positional variation, however, does not show any systematic effects on the variations of the measured acoustic quantities. Overall vowel duration and syllable duration are longer in English tokens but involve less variability across the prosodic variations. The constancy of syllable duration, therefore, is not found to be more strongly sustained in Korean CDS. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• Safety and Health at Work
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• 제12권3호
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• pp.311-316
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• 2021

Background: The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. Methods: We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014-2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5-9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. Results: There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37-8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. Conclusion: Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.809-815
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• 1998

This study has been performed to investigate MRR(metal removal rate) surface roughness with various pulse-on duration using the copper and graphite electrode according to the electrode size on the heat treated STD 11 which is extensively used for metallic molding steel in the EDM. The results obtained are as follow ;a)MRR increases a lot when pulse-on duration is 100 $\mu{s}$ or less but MRR has little difference with pulse-on duration of 100 $\mu{s}$ or more b) According to the increase of Pulse-on duration the large the electrode size the more MRR c) Safe discharge is needed to make maximum of MRR and the metallic organization must be complicated for discharge induction. d) Actual machining time is longer than theoretical machining time at the short pulse-on duration because of skin effect of current. e) Graphite electrode needs the larger electric discharge energy than copper electrode to remove remained chips completely.

• 대한치과의사협회지
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• 제51권6호
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• pp.346-354
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• 2013

Early identification of maxillary canine impaction is very important, because of treatment duration time. Analysis used by 3-dimensional computed tomography is more important than before in treatment planning. The aim of this study was to analysis of factors associated with the treatment during time of forced eruption of the impacted maxillary canine using 3-dimensional computed tomography. 17 patients were analysed in Daejeon dental hospital of Wonkwang university(16 patients with unilateral impactions and 1 patient with bilateral impaction). In total, 18 maxillary impacted cannines were analysed by 3-dimensional computed tomography. The results obtained were as follow; 1. There was positive correlation between the age of patient and treatment duration time. 2. There was positive correlation between the distance of occlusal plane to cusp of maxillary impacted canine and treatment duration time, and negative correlation between the length of maxillary impacted canine and treatment duration time. 3. There was positive correlation between the angulation of midsagittal plane to axis of maxillary impacted canine and treatment duration time, and negative correlation between occlusal plane to axis of maxillary impacted canine and treatment duration time. In conclusion, age, tooth length, distance from the canine cusp tip to the occlusal plane, angulation of tooth axis to occlusal plane and midsagittal plane allow that we can predict treatment duration time.

• 한국도로학회논문집
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• 제19권5호
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• pp.153-162
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• 2017

PURPOSES : This study was conducted to analyze the effects arising from extending the duration of nighttime road construction on improving road quality and durability. METHODS : Most previous studies estimating the social cost of various construction conditions did not consider road pavement cooling time as a factor in improving road pavement quality. This study investigated the feasibility of achieving higher road quality and durability by extending the duration of nighttime road construction time extension. For this investigation, the effects of such an extension on traffic conditions were analyzed based on micro-simulation studies and scenario-based cost-benefit analyses, using factors including traffic volume, delay, construction cost, and road pavement cooling time. RESULTS : The results of the traffic simulation studies and cost-benefit analyses indicate that the current road construction method that emphasizes completing nighttime road construction by 6 a.m. reduces pavement life while causing relatively little traffic delay. If the night construction time is instead extended to 2 p.m., road pavement lifetime is increased, reducing road re-construction cost. These savings are greater than the cost of congestion arising from extending the duration of nighttime construction. CONCLUSIONS : The current nighttime construction durations need to be extended in order to efficiently manage roads and reduce road management costs.

• 무역상무연구
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• 제15권
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• pp.137-165
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• 2001

The study on the duration of risk in the marine insurance has been paid a great attention because the marine insurance has to provide several indemnity conditions including the one to be compensated the loss when the accident happens. The research examines as to how the duration of risk has been extended from the beginning period to now. The results show the duration of risk has been continually extended in terms of place and time by a dramatic change of environment related to the marine insurance including marine transportation, a variety of goods, development of marine communication, many different trading conditions, etc, and requirement of the assured. The validity of the duration of risk is effected when the ship leaves at the port and is terminated when the ship arrives at the final destination. It in the Lloyd's age has been started when the products was charged to the ship and terminated when the one was safely discharged to the destination. Recently, the duration of risk in England Marine Insurance attaches from the time the goods leave the warehouse or place of storage at the placed named for the commencement of the transit, continues during the ordinary course of transit and terminates on delivery to the consignees or other final warehouse or place of storage at the destination named. Further research on the extension of the duration of risk must be conducted according to the being large scale of the ship and goods.