• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.5
• /
• pp.426-432
• /
• 2000

A novel mixed-integer linear programming model for the short-term scheduling of a sequential multipurpose batch plant is addressed. First, a time slot domain to each unit is introduced. By assigning each time slot to a product, we obtain the production sequence that minimizes makespan. For multiple-unit assignment problem where a few parallel units with the same function exist, production paths are defined for the distinction of the same stage with a different unit. As a second issue, the model adapted for sequence dependent changeover is presented. For a time slot of a unit, if a product is assigned to the time slot and a different product is assigned to the adjacent time slot, the changeover time considering this situation is included. The performance of the proposed models are illustrated through two examples.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.2
• /
• pp.156-164
• /
• 2019

In this paper, we propose an efficient dynamic slot re-assignment scheme for swarming drone networks in which networks members merged and split frequently. The leader drone of each network recognizes the slot allocation information of neighbor networks by periodic information exchange among between the drones. Using the information, the leader drone makes a decision how to reallocate the slots between members in case of network merge. The non-competitive method in the proposed scheme can re-assign the slots without any slot collision and shows always superior performance than competitive scheme. The competitive method in the proposed scheme reduces the number of slots that should be re-assigned in case of network merge. The experimental performance analysis shows that the proposed scheme performs better or at least equal to the performance of the competitive scheme in a swarming drone network.

• Proceedings of the IEEK Conference
• /
• 2000.06a
• /
• pp.131-134
• /
• 2000

Only MAC protocol can satisfy the service quality of the request of bandwidth, delay time, and cell loss at the same time and it is because MAC protocol provides mobile terminal an environment to use channel evenly and effectively This Paper has been adapted Mobile ATM Standardization of ETSI in maximum and used not only for practicing in-band signal to a priority order but also to the next reserved slot assignment of the dynamic frame. Also, by accepting VBR traffic more adaptively, the effectiveness of transmission channel has been maximized as well, and these are compared with the old way of it and analyzed to confirm the effectiveness.

• Journal of Intelligence and Information Systems
• /
• v.5 no.1
• /
• pp.145-166
• /
• 1999

오늘날의 컨테이너 터미널의 실정은 예산 및 부지확보의 어려움, 그리고 환경문제 등에 부딪혀 시설 확충 및 신설이 거의 불가능하다. 따라서, 경쟁력이 있는 터미널이 되기 위해서는 터미널의 운영방법을 개선하고 자동화하여 컨테이너 트럭, 선박 등 운송수단의 대기시간과 취급장비의 사용을 줄여줌으로써 물류비용을 감소시키는 동시에 소비자에 대한 서비스 수준을 높이고, 결과적으로는 항만의 국제 경쟁력을 높일 수 있기 때문에 효율적인 운영방법에 대한 연구가 더욱 요구되고 있다. 본 논문에서는 터미널의 운영방법의 중요한 요소인 컨테이너 장치위치 결정법에 출고지역, 출고 날짜, 무게 등의 복합 결정요소를 적용하여 이를 자동화하는 계획(planning) 시스템을 구현하고자 하며, 계획자의 구현에 초점을 두고있다.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.28 no.4
• /
• pp.21-29
• /
• 2003

The traffic scheduling problem for a satellite cluster with an arbitrary number of satellites is considered. which is one of the most interesting problems in the satellite communication scheduling area. This problem is to find a time slot assignment maximizing the transponder utilization for a satellite cluster This problem is known to be NP-complete, and several heuristic algorithms have been proposed. In this paper, we suggest new efficient algorithms for this problem, which have less time complexity than the best existing one and provide much better solution quality. Extensive simulation results are reported.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.3
• /
• pp.8-17
• /
• 1999

무선 ATM망에서 다수 연결채널로부터 발생되는 트래픽의 서비스 질을 보장하고 한정된 무선 자원을 효율적으로 사용하기 위해서는 다중접속제어 기술이 중요한 설계요소 중 하나이다. 본고에서는 ATM 프로토콜 특성을 무선 구간에 까지 확장한 동적다중슬롯할당(DMSA: Dynamic Multi-Slot Assignment)기법의 단점 중 하나인 연결채널별 지연 성능의 차이에 대해 분석하고, 이를 해결하기 위하여 이동국으로부터 각 연결채널에 대해 전달되는 정보를 이용하여 중앙제어국에 가상큐를 도입하는 방안을 제안한다. 중앙제어국에서는 구성된 가상큐룰 이용하여 상향링크의 다음 한 프레임내 모든 타임슬롯에 대한 연결채녈 할당을 수행한다. 다양한 트래픽 소스에 대한 시뮬레이션을 통해 가상큐-동적다중슬롯할당 알고리즘이 기존의 동적다중슬롯할당 알고리즘에 비해 중앙제어국에서의 단순한 제어 부하만으로도 다수의 연결채널에 대해 균등한 설비스 질을 보장하고 지연 변이 특성의 성능 향상을 나타냄을 입증한다. 이러한 연구결과는 동종 혹은 이종의 트래픽을 가진 각 연결 채널에 대해 무선 구간의 분산 환경으로 인해 발생할 수 있는 불평등성을 해결함으로써 무선 ATM의 개념을 우선 ATM과 유사한 환경으로 분석할 수 있는 계기를 마련한 것으로 판단된다.

• Journal of IKEEE
• /
• v.6 no.2 s.11
• /
• pp.161-168
• /
• 2002

Network of these days, A transmission medium of information is replaced from electric signal to optical signal to accept various and increased network traffic. In this paper, we develop simulation program using AweSim and simulate EPON system as a high-speed optical subscriber network with various conditions. The effects of number of ONUs, effects of network load and effects of slot assignment schemes have been evaluated. The simulation results show that slot assignment schemes and number of ONUs is major factor of network performance. The variable-number slot scheme is more efficient than fixed-length slot scheme in the traffic processing.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1999.04a
• /
• pp.530-530
• /
• 1999

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.85-85
• /
• 2000

• ETRI Journal
• /
• v.32 no.5
• /
• pp.819-822
• /
• 2010

Supporting QoS over multihop wireless mesh networks is difficult because end-to-end delay increases quickly with the increasing number of hops. This paper introduces a novel multichannel time-division multiple-access media access control (McTMAC) protocol that can help to efficiently reduce delay over multihop networks. Performance evaluation results demonstrate that McTMAC outperforms existing alternative protocols. The max-delay can be reduced by as much as 60% by using McTMAC.