• 한국학교보건학회지
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• 제16권2호
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• pp.25-34
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• 2003

Instroduction: The purpose of this study was to investigate safety education-related backgrounds and safety behaviors of elementary school children at a local area in Jeonbuk province. Methods: Study subjects were 308 5th and 6th graders from 6 schools located in J City and the data were collected from June 16-27, 2003. Research instrument to test safety behaviors was 4-points summated scale (Cronbach${\alpha}$= .94) composed of 54-items with three sub-categories school life safety (${\alpha}$= .88), traffic safety (${\alpha}$= .86), and daily life safety (${\alpha}$= .84), The data was analyzed by percentage, x2-test, t-test, ANOVA and Duncan test using SPSS/PC 10.0. Results: 1. Safety Education-related Characteristics: Safety education was mostly conducted during extracurricular hour as picnic (37%) and regular class (37.2%); and the instructors of safety education were school nurse (33.2%), classroom teacher (30.9%), and parents (23.4%) in order. About two third (71.0%) of the subjects have had many kinds of school event program such as essay writing, poster drawing, oratorical contest in the course of safety education According to gender, girl students was more favorable about school events as a effective safety education measure (x2=9.188, p= .010); and according to school location, nural school taught more at moming & closing session (x2=7.383, p= .025), by school nurse or classroom teacher (x2=36.574, p= .001), and had more frequent (x2=63.337, p= .001) safety education class. 2. Practice of safety behaviors: Mean scores of safety behaviors was $106.9{\pm}24.92$ out of 162 points. According gender, the scores of girl students (t=-3.296, p= .001) were significant higher than boy students. But there was not any significant difference according to school area According to safety education-related characteristics, the scores of safety behaviors was significantly higher in the group who thought that school event program was more effective on safety education (F=4.024, p= .019), and who were more interested in current safety education class (F= 10.203, p= .001) Conclusions: From the above findings, the authors concluded that school-based safety education was mainly conducted at extra-curricular and regular class, and by school nurse or classroom teacher in elementary school. Even though the mean scores of safety behaviors of elementary school children was in medium level, those. were significant higher in girl students and in rural school children. And extra-curricular activities and school event programs were suggested as more effective strategies for school-based safety education Based on the above findings, safety education class can be recommended in regular curricular basis; and various extracurricular activities and school event programs need to be developed for more effective school-based safety education. In addition, further study on gender-specific factors on safety behaviors and nationwide survey on school-based safety education should be needed.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.7675-7681
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• 2015

Background: Hazardous health behaviour in young people is an important factor that affects the individual risk for non-communicable diseases and other disorders later in life. This study aimed to determine the hazardous health behaviour of first and last class medical students of Erciyes University. Materials and Methods: This descriptive study was carried out with 240 medical students from the first and 130 students from the last (sixth) class. Data were obtained by questionnaire between March-April 2012. In total, 339 students were included with a response rate of 91.6%. Socio-demographic characteristics, school success, self-reported economic difficulties, health perceptions, hazardous health behaviour related to chronic disease, tobacco, alcohol, substance use, body weight, height, traffic, violence and nutrition were assessed in line with the literature. Results: Of the participants; 64.0% were from first and 36.0% were from the last class. Mean ages for the first and last classes were $19.4{\pm}1.5$ and $24.0{\pm}1.5years$, respectively. In the current study, males exhibited more hazardous behaviour than females. Sime 19.8% of the students in the study group used alcohol, 35.4% used a waterpipe, and 24.8% used tobacco at least once. These rates increased in both genders in the last class and the increase in males was significant. Some 3.8% of the students in the current study used pleasure-inducing illegal substances at least once. All the students participating in the current study were single, the number of males reported not using condoms (8.6%) was 4.56 times higher compared to females. Some 64.0% of the students did not perform physical activity lasting at least 30 minutes for five times a week, 13.0% did not sleep for mean 7-8 hours daily, males having a 2.9 times higher risk. More than 1/3 of the students did not consume cooked vegetable dishes and 1/4 did not consume fresh fruits and salads, the rates were higher among males. Conclusions: In the current study, hazardous health behaviour was prevalent among medical students, with higher risks among males and last class students. According to these results, medical curriculum may be focused on decreasing hazardous health behaviour. In addition, in order to prevent unhealthy behaviour, the number of youth-friendly health facilities should be increased.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.9-12
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• 2000

Today, QoS is one of the most critical issues in the network research area and Differentiated Services (DiffServ) is considered as the most prominent solution to provide some kinds of service differentiation without introducing any scalability problem. Among DiffServ's approaches, Assured Service (AS) provides some minimal level of QoS guarantee by treating more preferably than traditional Best Effort (BE) traffic and by using different level of drop probabilities within the same AS classes. In this paper, we investigate the ECN's capability of improving overall goodput of the flows and the possibility of resolving the fairness problem among the flows belonging to same class in Differentiated Services architecture.

• 한국정보과학회논문지:시스템및이론
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• 제26권3호
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• pp.363-370
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• 1999

본 연구는 멀티미디어 서비스를 무선 ATM 환경에서 지원하기 위한 WATM MAC프로토콜을 제안하였다. 무선 환경에서는 값비싼 무선 자원을 효율적으로 사용하여 ATM 서비스가 요구하는 QoS를 만족시키는 것이 중요하다. 특히 대역폭의 사용이 가변적인 비디오 트레픽의 경우는 유연한 대역폭 할당 기능이 있어야 한다. 이를 위하여 본 연구에서는 VBR과 CBR을 구분하여 제어하는 셀 스케쥴링 방식을 제안하였다. 이때 VBR 트레픽은 GCRA 알고리즘을 사용하여 가변적인 트레픽 요구를 만족시키도록 하였따. 제안된 제어 기법의 성능을 알아보기 위해 모의 실험을 통하여 성능을 평가하였다.

• 한국경영과학회지
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• 제20권1호
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• pp.35-54
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• 1995

Routing in ATM network is set up by combination of both virtual path routing and virtual channel routing. While virtual channel is similar concept to virtual circuit of data networks, virtual path is a special concept which is not used in traditional data networks. Virtual path can rearrange in structure and size by simply changing virtual path routing tables and giving the network the capability to eash allocate network resources according to the demand needs. This paper provides reconfiguration models of virtual path network which give the bandwidth of link and the routing path for each traffic class. The reconfiguration models are network optimization problems of multicommodity network flow type. The numerical examples are also included.

• 한국경영과학회지
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• 제21권1호
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• pp.1-17
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• 1996

There have been considerable researches for solving large-scale separable convex optimization ptoblems. In this paper we present a method for large-scale nonseparable smooth convex optimization problems with block-angular linear constraints. One of them is occurred in reconfiguration of the virtual path network which finds the routing path and assigns the bandwidth of the path for each traffic class in ATM (Asynchronous Transfer Mode) network [1]. The solution is approximated by solving a sequence of the block-angular structured separable quadratic programming problems. Bundle-based decomposition method [10, 11, 12]is applied to each large-scale separable quadratic programming problem. We implement the method and present some computational experiences.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.261-264
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• 2000

When there ate several classes of customers demanding service times with different distributions at some stations of a queueing network, the stability problem becomes suddenly complicated compared with the single class case. Recently many researchers had tried to find some kind of stability conditions for multiclass queueing networks, but did not get significant results except in very limited 2-station cases. In this study, we try to develop some dynamic control techniques which can guarantee the stability under the nominal traffic condition. Our approach includes the randomization method and the leaky bucket control scheme. Also, we mention other possibilities such as the discrete-review approach and the generalized round-robin technique. Both theoretical and experimental results will be presented.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 춘계 종합학술대회 논문집
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• pp.405-408
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• 2006

광대역망에서 다양한 트래픽의 종류에 따른 셀 손실율과 셀 지연율의 요구사항을 만족시킬 수 있는 제어시스템의 설계는 매우 중요한 요소이다. 본 논문에서는 트래픽의 각 클래스 타입에 따라 셀 카운터와 윈도우 카운터를 이용한 우선순위 제어 기법을 제안하였다. 제안한 기법에서는 요구된 서비스의 질을 만족시키기 위해 셀 카운터와 윈도우 카운터의 비교에 의해 얻어진 셀 손실과 지연요소를 획득하여 우선순위 제어를 수행하였다. 그리고 컴퓨터 시뮬레이션을 통하여 성능을 평가하였다.

• 한국통신학회논문지
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• 제25권7B호
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• pp.1313-1319
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• 2000

MPLS에서 ATM의 스위칭 기능은 인터넷 백본망에 대해 효율적인 전송을 제공할 것이다. 특히, VC merging은 다수의 IP 경로와 한 VC 레이블간의 대응을 가능케 함으로써 망의 확장 시에도 유연하게 대처 할 수 있다. 이미 VC merge 관련 메커니즘들이 제안되어 있으나 단지 best-effort 트래픽에 대해서만 가능하며 다중 클래스 트래픽에 대해 각 QoS를 충족시키는 구체적인 방안은 제시되어 있지 않다. 따라서, 본 논문에서는 각 클래스의 VC merge시, 동적 대역폭 할당을 적용해 merge된 트래픽의 QoS를 만족시키는 메커니즘 및 ATM-LSR의 구조를 제안한다. 아울러, 시뮬레이션을 통해 제안된 동적 VC 대역폭 할당 방안에 대한 성능 평가를 수행하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(II)
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• pp.1174-1177
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• 1987

The design of flow control protocols for integrared networks with complete voice traffic on the data link level is investigated. The class of admissible flow control policies analyzed maximized the average data link throughput subject to an average system time delay constraints a finite intervals (O,s). In particular, it is shown that the optimum control law is bang-bang (window flow mechanism). The window size L can be analytically derived from maximum tolerated time delay T, the input arrival C of the queueing system, the duration of the time interval S, the initial number of packets in the queue.