• 한국컴퓨터정보학회논문지
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• 제16권9호
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• pp.107-114
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• 2011

다양한 서비스를 제공하는 통신 기기의 활성화 및 모바일 사업의 급속한 확대로 인해 기존 네트워크 설비의 효율적인 활용 및 운용이 매우 중요시 되고 있다. 이와 함께 개인별 편차가 큰 사용자의 통신 요구 수준에 부합하는 서비스의 제공은 통신 사업자에게 매우 중요하다. 본 논문에서는 이러한 것들을 모두 만족시킬 수 있는 최소 연결 비용의 네트워크를 효과적으로 구성하여 네트워크 QoS를 구현하는 SGOSST를 제안한다. 실험에서 제안된 방법으로 생성된 SGOSST QoS 네트워크는, 가중치 반영 최소 신장 트리 방법으로 구현된 QoS 네트워크에 비해 실행시간은 252.97% 증가했으나, 네트워크 구성을 위한 연결 비용은 5.11% 감소하였다. 따라서 제안된 방법은 스마트 및 모바일 기기 등 다양한 서비스 요청 등급의 통신 기기들과 사용자들로 구성된 네트워크에서 효율적인 운용 및 서비스 제공 등에 잘 적용될 수 있을 것이다.

• 대한교통학회지
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• 제22권7호
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• pp.147-154
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• 2004

COSMOS에서 포화도에 따른 현시 배분시 최소녹색시간에 의해 영향을 받는 경우 불균형적인 배분이 발생한다. 포화도에 따라 배리어를 나누게 되면 수요가 많은 광로측 배리어의 값이 더 많이 배분되고 상대적으로 소로측 배리어는 적게 배분된다. 배리어 배분 후 포화도에 따라 현시를 배분하면 최소녹색시간 확보로 인해 직진 이동류가 사용 가능한 녹색시간의 대부분을 쓰게 되므로 좌회전의 경우 녹색시간이 짧아져 통행권이 박탈당하는 문제가 발생한다. COSMOS에서는 이러한 문제점을 안고 있는 지역을 이중횡단보도를 설치하여 횡단보도 중간에 보행자용 교통섬을 설치하여 좌회전 현시와 이어지는 직진현시를 이용하여 횡단하도록 하였다. 본 연구에서는 이를 개선하기 위해 최소녹색시간을 고려하여 배리어를 계산하고 이동류별 포화도 비율에 따라 녹색시간을 계산한다. 개선 방안의 평가를 위해 아주대학교에서 개발한 COSMOS 평가 시뮬레이터를 이용하여 기존 알고리즘과 개선알고리즘으로 v/c비 $0.4{\sim}1.2$ 범위의 교통상황별로 지체시간을 비교하였다. 향후 개발된 알고리즘의 교통상황에 따른 적용시점에 관한 연구가 추가되어진다면 신호교차로의 운영효율을 극대화시킬 수 있을 것으로 기대된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.383-387
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• 1989

In this paper, an adaptive algorithm for processes with unmeasured deterministic disturbances is presented. This algorithm is simple to synthesize an adaptive controller with desired pole/zero assignment. The internal stability requirement is achieved so that this algorithm can easily handle any minimum or non-minimum phase system. Some simulations are given to show the applicability of this approach.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.117-126
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• 2011

The buckling assessment of plate panels described in common structural rules (CSR) is to be determined according to the buckling utilization factor with hull girder stresses calculated on net hull girder sectional properties. As the thickness requirement for the buckling assessment of plate panels is not explicitly given in CSR, a lot of time is spent to find the proper thickness of plate panels until reaching to an allowable buckling utilization factor. In this study, in order to reduce time and cost, the thickness requirement of plate panels satisfying buckling assessment was derived. The structural design system included with the thickness requirement for buckling assessment was developed. The system is called as Oil-tanker Automated Structural Investigation System (OASIS). The design result of longitudinal strength members using OASIS was verified by Nauticus Hull which is the rule scantling software of DNV. Finally, optimum design of a double hull tanker for the minimum weight using OASIS was presented.

• Journal of Advanced Marine Engineering and Technology
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• 제27권3호
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• pp.388-394
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• 2003

Hydraulic system is difficult to obtain a suitable performance due to the nonlinearity load pressure change and system parameter variation. The requirement of control a1gorithm has been complex in order to satisfy the performance. The adaptive control is a control method which is suggested to achieve the control object under the plant characteristics change. In spite of the case that plant characteristics and the degree of variation are difficult to grasp. the adaptive control could keep the characteristics of closed-loop system generally. In this study. a method of combined generalized minimum variance adaptive control (GMVAC) and output error feedback is proposed, in order to solve the problem of non-minimum phase of plant and the vibration and overshoot in initial response. The control performance according to the variation of characteristics of plant is evaluated by changing the supply pressure. The experimental results show the effectiveness of the proposed scheme.

• Safety and Health at Work
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• 제10권3호
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• pp.389-392
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• 2019

When conducting an exposure assessment, the primary goal of the industrial hygienist is to fully characterize the worker's exposure during a work shift to compare it with an occupational exposure limit. This applies regardless of the duration of the work activity as an activity that is relatively short in duration can still present exposure in excess of the occupational exposure limit even when normalized over an 8-hr shift. This goal, however, is often impeded by the specification of a minimum sample volume in the published sampling method, which may prevent the sample from being collected or submitted for analysis. Removing the specification of minimum sample volume (or adjusting it from a requirement to a recommendation), in contrast, allows for a broader assessment of jobs that consist of short-duration and high-exposure activities and also eliminates the unnecessary practice of running sampling pumps in clean air to collect a specified, minimum volume.

• Asian-Australasian Journal of Animal Sciences
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• 제9권6호
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• pp.643-646
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• 1996

Experiments were conducted to determine potassium (K) requirement of mule ducklings. One-day-old ducklings with equal number of both sexes were fed diets containing graded levels of K for three weeks. In experiment 1, corn-soybean meal diet (CP 18.7%, ME 2,890 kcal/kg, K 0.80%) was used. The addition of K (0.00, 0.10, 0.20, 0.30, 0.40%) to the diet by potassium carbonate resulted in a decrease in weight gain and feed efficiency with the group fed on basal diet having the best performance. This means that the existing K in the basal diet is adequate for the growth of ducklings. In experiment 2, low K corn-isolated soy protein diet (K, 0.19%) was used. The supplementation of K (0.00, 0.16, 0.32, 0.48, 0.64%) resulted in an increase in weight gain and feed efficiency with the control group having the lowest performance. The minimum K requirement was found to be 0.49% for both maximum growth and best feed efficiency as determined by using bent-stick model.

• 한국농림기상학회지
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• 제8권2호
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• pp.68-76
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• 2006

A thermal time-based two-step phenological model was used to project flowering dates of Japanese cherry in South Korea from 1941 to 2100. The model consists of two sequential periods: the rest period described by chilling requirement and the forcing period described by heating requirement. Daily maximum and minimum temperature are used to calculate daily chill units until a pre-determined chilling requirement for rest release is met. After the projected rest release date, daily heat units (growing degree days) are accumulated until a pre-determined heating requirement for flowering is achieved. Model calculations using daily temperature data at 18 synoptic stations during 1955-2004 were compared with the observed blooming dates and resulted in 3.9 days mean absolute error, 5.1 days root mean squared error, and a correlation coefficient of 0.86. Considering that the phonology observation has never been fully standardized in Korea, this result seems reasonable. Gridded data sets of daily maximum and minimum temperature with a 270 m grid spacing were prepared for the climatological years 1941-1970 and 1971-2000 from observations at 56 synoptic stations by using a spatial interpolation scheme for correcting urban heat island effect as well as elevation effect. A 25km-resolution temperature data set covering the Korean Peninsula, prepared by the Meteorological Research Institute of Korea Meteorological Administration under the condition of Inter-governmental Panel on Climate Change-Special Report on Emission Scenarios A2, was converted to 270 m gridded data for the climatological years 2011-2040, 2041-2070 and 2071-2100. The model was run by the gridded daily maximum and minimum temperature data sets, each representing a climatological normal year for 1941-1970, 1971-2000, 2011-2040, 2041-2070, and 2071-2100. According to the model calculation, the spatially averaged flowering date for the 1971-2000 normal is shorter than that for 1941-1970 by 5.2 days. Compared with the current normal (1971-2000), flowering of Japanese cherry is expected to be earlier by 9, 21, and 29 days in the future normal years 2011-2040, 2041-2070, and 2071-2100, respectively. Southern coastal areas might experience springs with incomplete or even no Japanese cherry flowering caused by insufficient chilling for breaking bud dormancy.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.386-387
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• 2012

마리나는 쾌적하고 안전한 환경조성이 매우 중요하기 때문에 마리나 시설이 위치한 해역의 특성을 고려한 환경관리 및 설계가 필요하다. 특히 해역환경은 시간적-공간적인 변화가 크기 때문에 체계적인 조사가 선행되어져야 하며, 표준화된 하나의 설계 및 관리기준을 따르기 보다는 실질적으로 달성가능하고 최소 요구수준을 만족하는 정도에서 관리수준이 결정되어져야 한다. 본 논문은 마리나 환경관리를 위한 기본 단계와 각각의 단계에서 필요로 하는 기술제시를 목적으로 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권12호
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• pp.3071-3095
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• 2013

Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.