• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.274-287
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• 2009

In the Internet environment in which best-effort services are provided, we need to guarantee end-to-end performance rather than hop performance to provide services with a variety of QoS(Quality of Service) requirements. The end-to-end performance is affected by many factors along the path of traffic flow. Most existing simulation studies are concentrated on a single node or a few nodes. We need much different approach considering the simulation execution time to simulate a large-scale network. In this paper, we derive requirements and present methodologies for the implementation of the simulator to simulate it. Then, we design and implement our simulator using OPNET. Performance evaluation is carried out using the simulator for large-scale KII (National Information Infrastructure in Korea). We use a self-similar traffic model and present some results on the end-to-end performance metric for the networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2548-2566
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• 2012

This paper derives two main end-to-end performance metrics, namely the spatial capacity density and the average end-to-end delay of the multi-hop wireless ad hoc networks with multi-antenna communications. Based on the closed-form expressions of these performance metrics, three hopping strategies, i.e., the closest neighbor, the furthest neighbor and the randomly selected neighbor hopping strategies have been investigated. This formulation provides insights into the relations among node density, diversity gains, number of hops and some other network design parameters which jointly determine network performances, and a method of choosing the best hopping strategy which can be formulated from a network design perspective.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.11
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• pp.1119-1127
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• 2007

This paper is concerned with a performance analysis using a wired/wireless hybrid network based on Common Industrial Protocol(CIP). For the performance analysis, the data transmission time, average end-to-end delay and throughput between DeviceNet and the wireless devices are investigated. The experimental results show the performance in terms of the polling/COS service time of CIP based hybrid network.

• The Journal of Engineering Research
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• v.6 no.2
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• pp.39-46
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• 2004

In this paper, we carry out a performance study related to the Broadband Network. For this network, it has been proposed to use the leaky bucket as a way of controlling congestion within the network. On the top of leaky bucket type rate based congestion control scheme for high speed networks, a user will typically operate an error control scheme for retransmitting lost and erroneous packets. We propose a performance model in order to study the interaction between a user's error control scheme and the leaky bucket congestion control scheme for high speed networks. Simulation results show that parameters such as the window size and the token generation rate in the leaky bucket are key factors affecting the end-to-end delay.

• Steel and Composite Structures
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• v.44 no.3
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• pp.339-351
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• 2022

A mortar-filled rectangular hollow structural section (RHS) can increase a structural section property as well as a compressive buckling capacity of a RHS member. In this study, the tensile performance of newly developed mortar-filled RHS members was experimentally evaluated with various connection details. The major test parameters were the type of end connections, the thickness of cap plates and shear plates, the use of stud bolts, and penetrating bars. The test results showed that the welded T-end connection experienced a brittle weld fracture at the welded connection, whereas the tensile performance of the T-end connection was improved by additional stud bolts inserted into the mortar within the RHS tube. For the end connection using shear plates and penetrating stud bolts, ductile behavior of the RHS tube was achieved after yielding. The penetrating bars increased load carrying capacity of the RHS. Based on the analysis of the load transfer mechanism, the current design code and test results were compared to evaluate the tensile capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled RHS tubes were also recommended.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.69-72
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• 2002

The geometry parameter of tool such as rake angle and clearance angle is defined clearly to solve the difference in communication between design and measurement stage. Using the developed simulation program, wheel is properly determined and end mill can be manufactured accurately. The performance test with well defined end mill provides sufficient information to decide optimal geometry. For machining hardened steel, end mills are designed and manufactured. Optimal rake angle and clearance angle is obtained from performance test. A specific software for automatic end mill production is developed far simulation and fur generation of NC code as Cad/CAM system.

• Journal of Power Electronics
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• v.11 no.5
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• pp.697-703
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• 2011

In this paper a control system with a high performance dynamic response for linear induction motors (LIMs) is proposed which takes into account the end-effect in both the machine model and the control system. Primary flux oriented control has two major drawbacks i.e. a lack of decoupling of the thrust and the flux and a possibility of system instability due to the end-effect. Both of these drawbacks have been dealt with in this paper. A flux estimation method is proposed to correct the flux orientation error caused by the end effect. Extensive motor performance evaluations under the proposed control system prove its superiority over conventional vector control.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.6
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• pp.329-337
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• 2013

In multihop routed ad hoc networks, the conventional store-and-forward delivery has been used. However, we may ask a question: "Is the store-and-forward delivery still the best?" This paper presents a pipeline-through MAC (PT-MAC) protocol for ad hoc networks, in which nodes have two 3-channel interfaces in order to use limited radio resources efficiently and improve network performance. The proposed protocol reduces end-to-end delay significantly in multihop routed transmission by exploiting a novel pipeline-through technique rather than using the conventional store-and-forward. This results in improved network performance without increasing control overhead. Our extensive performance study shows that the proposed PT-MAC shows 20-40 percent shorter end-to-end delay and 25-55 percent better goodput compared to the IEEE 802.11 DCF with two 3-channel interfaces.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.4
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• pp.240-251
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• 1987

In this paper, with the end effect taken into consideration, the fundamental characteristics of a linear induction motor-the eddy currents of the secondary conducting sheet (traveller), the flux density in the air gap-are analysed by means of electromagnetic field theory. Accordingly, the derived governing eqations of the chatacteristics with goodness factor, presents that it was possible not only to predict the performance characteristics, but to obtain the data that needs to optimize a design of a motor with the reduction of the end effect.

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