• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.10
• /
• pp.1-7
• /
• 1992

This paper proposes reservation-based multiple access with variable frame length (RMAV) which is a new multiple access scheme for indoor and outdoor wireless data communications. RMAV is based on the slot reservation scheme and adopts a frame structure with variable frame length. The frame length increases as the number of active terminals and/or the system load increases. As a result, RMAV is adapted to the changes in the traffic pattern, and it offers short delay in light load conditions and high throughput in heavy load conditions. The performance of RMAV is evaluated by simulations. In addition, it is compared with the performance of PRMA(packet reservation multiple access).

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.4
• /
• pp.17-24
• /
• 2016

In this paper, we propose a AH LSU(Advanced Hybrid QoS Routing Link State Update) Algorithm that improves the performance of Hybrid LSU(Hybrid QoS Link State State Update) Algorithm with statistical information of flow holding time in network. AH LSU algorithm has had both advantages of LSU message control in periodic QoS routing LSU algorithm and QoS routing performance in adaptive LSU algorithm. It has the mechanism that calculate LSU message transmission priority using the flow of statistical request bandwidth and available bandwidth and include MLMR(Meaningless LSU Message Removal) mechanism. MLMR mechanism can remove the meaningless LSU message generating repeatedly in short time. We have evaluated the performance of the MLMR mechanism, the proposed algorithm and the existing algorithms on MCI simulation network. We use the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

• Structural Engineering and Mechanics
• /
• v.18 no.5
• /
• pp.609-626
• /
• 2004

The Land Transport Authority of Singapore has a continuing program of highway bridge upgrading, to refurbish and strengthen bridges to allow for increasing vehicle traffic and increasing axle loads. One subject of this program has been a short span bridge taking a busy highway across a coastal inlet near a major port facility. Experiment-based structural assessments of the bridge were conducted before and after upgrading works including strengthening. Each assessment exercise comprised two separate components; a strain and acceleration monitoring exercise lasting approximately one month, and a full-scale dynamic test carried out in a single day. This paper reports the application of extreme value statistics to estimate bridge live loads using strain measurements.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.20 no.2
• /
• pp.71-78
• /
• 2017

Child obesity has become a significant health issue in Korea. Prevalence of obesity in school-age children in Korea has been alarmingly rising since 2008. Prevalence of obesity among infants and preschool-age children in Korea has doubled since 2008. Obese children may develop serious health complications. Before nutritional counseling is pursued, several points should be initially considered. The points are modifiable risk factors, assessment for child obesity, and principles of treatment. Motivational interviewing and a multidisciplinary team approach are key principles to consider in managing child obesity effectively in the short-term as well as long-term. Nutritional counseling begins with maintaining a daily log of food and drink intake, which could possibly be causing obesity in a child. Several effective tools for nutritional counseling in practice are the Traffic Light Diet plan, MyPlate, Food Balance Wheel, and 'Food Exchange Table'. Detailed nutritional counseling supported by a qualified dietitian is an art of medicine enabling insulin therapy and hypoglycemic agents to effectively manage diabetes mellitus in obese children.

• Tunnel and Underground Space
• /
• v.23 no.5
• /
• pp.347-352
• /
• 2013

Recently, due to the gravitation of the population and traffic congestion, the land supply tends to be short. Underground space development is considered positively as a countermeasure. This study was to review the basic principles of underground space, to find out problems, and to propose the direction for the effective development of underground space.

• Proceedings of the KOR-KST Conference
• /
• 1998.10a
• /
• pp.21-30
• /
• 1998

본 연구는 기존 구간 속도 예측기법의 고찰을 통하여 검지기에서 올라오는 교통제어변수를 이용하여 구간 속도 예측모형을 연구하는데 목적이 있다. 이를 위한 교통 제어변수로는 연속류 제어에서 통상적으로 사용되는 교통량, 점유율, 밀도, 속도 등을 사용한다. 공간적 범위로는 서울 올림픽대로의 17개의 영상 검지기 중 #3과 #16검지기에서 올라오는 속도, 점유율, 교통량 자료를 토대로 1998년 6월 11일 오전 7시부터 11시까지의 4시간동안 예측을 실시하며 Historical Traffic Pattern과 시험차량, 자동차 번호판 조사를 통한 구간 실측조사 자료를 토대로 예측을 위한 자료를 구축한다. 기존의 예측기법인 시계열 분석, 신경망 이론, 평활법과 칼만필터링을 고찰하였고, 가장 좋은 예측력을 보여주는 기법은 칼만필터링 모형이었다. 이를 토대로 Case Study를 통해 여러 구간의 다주기 예측을 통해 단기간(short-term)의 구간 속도를 예측하고 각 해당 검지기별 실측자료를 통해 비교분석을 실시하였다. 결과적으로 도출된 칼만필터링 모형의 다주기 예측을 통한 구간 통행속도의 예측이 기존의 구간 통행속도 산출 방법보다 더 나은 예측력을 보여주고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.5
• /
• pp.1733-1751
• /
• 2015

The IEEE 802.15.4 standard not only provides a maximum of seven guaranteed time slots (GTSs) for allocation within a superframe to support time-critical traffic, but also achieves ultralow complexity, cost, and power in low-rate and short-distance wireless personal area networks (WPANs). Real-time wireless body area sensor networks (WBASNs), as a special purpose WPAN, can perfectly use the IEEE 802. 15. 4 standard for its wireless connection. In this paper, we propose an adaptive GTS allocation scheme for real-time WBASN data transmissions with different priorities in consideration of low latency, fairness, and bandwidth utilization. The proposed GTS allocation scheme combines a weight-based priority assignment algorithm with an innovative starvation avoidance scheme. Simulation results show that the proposed method significantly outperforms the existing GTS implementation for the traditional IEEE 802.15.4 in terms of average delay, contention free period bandwidth utilization, and fairness.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.10 no.1
• /
• pp.29-35
• /
• 2016

This paper presents an analysis of the short-range radar noise adjusting the angle of the radar reflector for the handicapped aids and suggests a complementary filter that combines a moving average filter with a heuristic algorithm to remove the radar noise. It also shows the effectiveness of the suggested filter by comparing the experiments results between the Kalman filter and the suggested filter.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.410-417
• /
• 2002

We consider the constraint based explicit routing problem in MPLS based IP Network. In this problem, we are given a set of traffic demands and a network with different link capacities. The problem is to assign the demand commodities to the paths in the network while minimizing the maximum link load ratio. We formulate this problem as an integer programming problem and propose an efficient column generation technique. To strengthen the formulation, we consider some valid inequalities. We also incorporate the column generation technique with variable fixing scheme Computational results show that the algorithm gives high quality solutions in a short execution time.

• Journal of Korean Society for Atmospheric Environment
• /
• v.9 no.E
• /
• pp.397-400
• /
• 1993

The possible air pollution problems in a proposed underground highway are discussed using carbon monoxide (CO) as an indicator. Carbon monoxide concentrations in the underground highway depend on several factors, including the size of tunnel, the number of automobiles, the CO emission rate, and the tunnel ventilation rate. Using the estimated values, CO concentrations in the underground highway can be predicted. Without proper ventilation system, CO concentration in the underground highway can be dangerous level. However, the cost of operating the mandatory mechanical ventilation system may be tremendouslyy high and may be technically unrealistic to implement. If the underground highway is constructed with proper ventilation system, a continuous air pollution monitoring system with alarming function must be installed to alert personnel of serious air pollution built up in the underground highway. Traffic must be restricted, whenever the inside air pollution levels exceed agreed values. Short distances between evacuation exits are necessary for emergency situations or malfunction of ventilation system.