This study addresses production planning in a multi-product, multi-machine environment. The products manufactured are high precision metal tubes. The production process consists of three major ...operations: pilgering, pickling/cleaning, and annealing. These three operations are repeated four to five times to make the final products. We first analyze the system capacity and then develop heuristics for the production scheduling problem. The scheduling system consists of MRP logic and the OPT concepts of backward and forward scheduling. Further, the effectiveness of the scheduling rules is studied by simulating flow of orders through the production process. The benefits of using such an integrated system are illustrated.
Charging is one of the most important functionalities in a telecommunication service system. In a general packet radio service (GPRS) wireless network, the load of charging information flow depends ...on the intensity of call traffic and the size of charging records. During busy hours, the GPRS network might not be able to transfer charging records on a timely basis if new charging records are generated too fast. On the other hand, when a call happens, the related charging information must be collected and transferred to the billing system. If a failure of the data link occurs, a secondary data link must be employed to transfer the charging information. However, this redundant operation might result in charging information duplication. This paper formally addresses these two issues. A timed Petri net model is built to support the analysis of the charging system performance versus various factors when the system works in the normal status, which, in particular, gives the maximum supportable busy hour call attempts of the GPRS network. The Petri net approach is also used to model and verify the correctness of the redundancy operation in case a connection failure occurs.
Coverage and capacity of a wireless mesh network Jane-Hwa Huang; Li-Chun Wang; Chung-Ju Chang
2005 International Conference on Wireless Networks, Communications and Mobile Computing,
2005, Volume:
1
Conference Proceeding
Wireless mesh networks (WMN) play an important role in the next-generation wireless communication systems because it can support broadband services with ubiquitous coverage by low transmission power. ...In this paper, we propose a multi-channel ring-based wireless mesh network and develop an analytical framework to evaluate the capacity and coverage of such a network. In the analytical framework, we first establish a physical (PHY)/medium access control (MAC) cross layer throughput performance model by including the carrier sense multiple access (CSMA) MAC protocol and distance-based rate adaptation with multi-hop connections. Based on the derived throughput model, we apply the mixed-integer nonlinear programming (MINLP) optimization approach to maximize the capacity (throughput) and service coverage of a mesh cell, in which the number of rings in a mesh cell and the radius for each ring are determined.
There have been so far small research works on highway weaving sections and the design and operation methods of the weaving sections have not yet established in Japan. In the U. S. A the analysis ...methods have been revised drastically in the new HCM-1985 compared to the old edition. However there remain still discussions on it among researchers. Several analysis procedure have been proposed so far and studies are going on still now. This paper reviews those development about the weaving analysis study and presents also the state of arts on the traffic flow characteristics and capacity study concerning weaving sections in Japan. It also perspectives the future study problems.
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