• Journal of Digital Convergence
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• v.3 no.2
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• pp.9-22
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• 2005

A large scale automated material handling system (AMHS) is simulated using real industrial input data to analyze its performance so that one can scrutinize the critical factors that affect the AS /RS performance. The factors included in this study are line balancing efficiency, the distance between machines, and cycle time of the machines. The performance of AS /RS is measured in terms of R/M utilities that are latter used to classify the AS/RS structure into three types such as Good, Normal, and Poor. Among the three factors considered in this study, the line balance efficiency within each AS/RS is found as the most critical factor which statistically affect the AS/RS performance.

• 한국디지털정책학회:학술대회논문집
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• 2005.11a
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• pp.411-424
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• 2005

A large scale automated material handling system (AMHS) is simulated using real industrial input data to analyze its performance so that one can scrutinize the critical factors that affect the AS/RS performance. The factors included in this study are line balancing efficiency, the distance between machines, and cycle time of the machines. The performance of AS/RS is measured in terms of R/M utilities that are latter used to classify the AS/RS structure into three types such as Good, Normal, and Poor. Among the three factors considered in this study, the line balance efficiency within each AS/RS is found as the most critical factor which statistically affect the AS/RS performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.117-126
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• 2009

The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. Some schemes, however, are prone to unbalance of the traffic and energy. To solve this problem, we propose a novel solution: a gradient-field approach which takes account of the minimum cost data delivery, energy consumption balancing, and traffic equalization. We also modify the backoff-based cost field setup algorithm to establish our gradient-field based sensor network and give the algorithm. Simulation results show that the overhead of routing establishment obtained by our algorithm is much less than the one obtained by Flooding. What's more, our approach guarantees the basic Quality of Service (QoS) without extra spending.

• ETRI Journal
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• v.40 no.5
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• pp.604-612
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• 2018

To solve the problem of unbalanced loads and the short network lifetime of heterogeneous wireless sensor networks, this paper proposes a node-selection algorithm based on energy balance and dynamic adjustment. The spacing and energy of the nodes are calculated according to the proximity to the network nodes and the characteristics of the link structure. The direction factor and the energy-adjustment factor are introduced to optimize the node-selection probability in order to realize the dynamic selection of network nodes. On this basis, the target path is selected by the relevance of the nodes, and nodes with insufficient energy values are excluded in real time by the establishment of the node-selection mechanism, which guarantees the normal operation of the network and a balanced energy consumption. Simulation results show that this algorithm can effectively extend the network lifetime, and it has better stability, higher accuracy, and an enhanced data-receiving rate in sufficient time.

• Journal of Power Electronics
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• v.11 no.6
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• pp.811-818
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• 2011

Modulation strategies for multilevel inverters have typically focused on synthesizing a desired set of sinusoidal voltage waveforms using a fixed number of dc voltage sources. This makes the average power drawn from different dc voltage sources unequal and time varying. Therefore, the dc voltage sources are unregulated and require that corrective control action be incorporated. In this paper, first two new selections are proposed for determining the dc voltage sources values for asymmetric cascaded multilevel inverters. Then two modulation strategies are proposed for the dc power balancing of these types of multilevel inverters. Using the charge balance control methods, the power drawn from all of the dc sources are balanced except for the dc source used in the first H-bridge. The proposed control methods are validated by simulation and experimental results on a single-phase 21-level inverter.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.381-384
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• 2002

This paper describes the motivation, design and performance of bi-active Load balancer in Linux Virtual Server. The goal of bi-active Load balancer is to provide a framework to build highly scalable, fault-tolerant services using a large cluster of commodity servers. The TCP/IP stack of Linux Kernel is extended to support three IP load balancing techniques, which can make parallel services of different kinds of server clusters to appear as a service on a single IP address. Scalability is achieved by transparently adding or removing a node in the cluster. and high availability is provided by detecting node or daemon failures and reconfiguring the system appropriately. Extensive simulation reveals that the proposed approach improves the reply rate about 20% compared to earlier design.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.432-433
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• 2018

A new DC-DC converter circuit for LVDC(Low Voltage Direct-Current) distribution is proposed. DC-DC converter consists of two stage which are voltage balancer and converter stage. The balancing circuit adjust balance input voltage of converter circuit and compensate for unbalanced loads and short circuits. The converter circuit control the bipolar output voltage ${\pm}750V$. Simulation is carried out for this DC-DC converter system.

• IE interfaces
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• v.8 no.3
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• pp.259-267
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• 1995

A printed circuit board auto-insertion line consists of several processes of identical machines and produces several different types of PCBs. Each board must be processed by at most one machine in each process. So, we call it a flexible flow line. The load balancing is the one of the most important issues in the FFL which has many sequential processes. Therefore we have represented the job route selection model to balance the load of inter-process in the PCB auto-insertion line, and validated it by simulation.

• Journal of Power Electronics
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• v.16 no.1
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• pp.133-141
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• 2016

This paper focuses on the development of a Five-Level Flying-Capacitor Dual Buck Inverter (FLFCDBI) based on the main circuit of dual buck inverters. This topology has been described as not having any shoot-through problems, no body-diode reverse recovery problems and the half-cycle work mode found in the traditional Multi-Level Flying-Capacitor Inverter (MLFCI). It has been shown that the flying-capacitor voltages of this inverter can be regulated by the redundant state selection within one pole. The voltage balance of the flying-capacitors can be achieved by charging or discharging in the positive (negative) half cycles by choosing the proper logical algorithms. This system has a simple structure but demonstrates improved performance and reliability. The validity of this inverter is conformed through computer-aided simulation and experimental investigations.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.214-215
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• 2017

Distributed Flexible AC Transmission System(D-FACTS) was proposed as a solution for weakness of FACTS device s. The D-FACTS device DSSC(Distributed Static Series Co mpensator) can provide controllable reactance compensation in transmission line such as SSSC(Static Synchronous Series Compensator). This paper introduce the algorithm of reactive power injection on DSSC and propose the method of current balancing by reactive power injection. The proposed algorithm has been verified with simulation and experiment results.