• Journal of IKEEE
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• v.24 no.1
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• pp.1-8
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• 2020

In this paper, a semi-infinite array analysis method is proposed to analyze the defects that may occur during the fabrication of the frequency selective radome. In the analysis of N×N finite array structure using 3D analysis software, much analysis time and memory are required, whereas the semi-infinite array structure analysis proposed in this paper can predict relatively accurate electromagnetic performance while reducing the analysis time. In comparison with the results of the periodic simulation, the simulation of the semi-infinite array structure confirmed the error within ±3%. To verify the results of the simulation, the results were compared with the measured results, and the same tendency at the point of performance change and similar performance degradation at the band of interest were investigated. Using the proposed semi infinite array structure analysis, it is confirmed that the analysis of defects in the electromagnetic periodic structure is possible.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.23-37
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• 1997

In this paper, performance analysis of video traffic shaper for Motion Picture Experts Group (MPEG) video traffic in on ATM network are investigated. Traffic shaping for MPEG video traffic is proposed as a traffic control function in ATM networks. The proposed shaper smoothes video traffics by controling the output rate of the buffer, which is placed in an MPEG source, according to I,B,P frame sequences of MPEG. In performance analysis of an video traffic shaper, a periodic botch arrival model is suggested to describe cell streams in a frame of MPEG video traffic. The queueing model which has periodic independent botch arrival and periodic deterministic service time is used to obtain the cell loss ratio, the mean cell delay, and the measure of smoothing effect. Simulation results are used to validate this queueing model. The cell loss performance of ATM multiplexer is measured by simulation study with real MPEG-1 data. From the viewpoint of traffic load, the cell loss ratio is observed to be considerably high, which is considered to result from the burstiness of MPEG video traffic. As a result, it is shown that the shaping decreases cell loss ratio of multiplexer. The results of this paper can be employed to establish a basic guideline in the implementation of a traffic control scheme and the design of ATM multiplexer for MPEG video traffic.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.87-101
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• 2013

In industrial applications, sensor networks have to satisfy specified time requirements of exchanged messages. IEEE 802.15.4 defines the communication protocol of the physical and medium access control layers for wireless sensor networks, which support real-time transmission through guaranteed time slots (GTSs). In order to improve the performance of IEEE 802.15.4 in industrial applications, this paper proposes a new traffic scheduling algorithm for GTS. This algorithm concentrates on time-critical industrial periodic messages and determines the values of network and node parameters for GTS. It guarantees real-time requirements of periodic messages for industrial automation systems up to the order of tens to hundreds of milliseconds depending on the traffic condition of the network system. A series of simulation results are obtained to examine the validity of the scheduling algorithm proposed in this study. The simulation results show that this scheduling algorithm not only guarantees real-time requirements for periodic message but also improves the scalability, bandwidth utilization, and energy efficiency of the network with a slight modification of the existing IEEE 802.15.4 protocol.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.343-348
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• 1988

This paper describes an application of the periodic scheduling policy to a class of flexible manufacturing systems. A heuristic algorithm is used to determine when each part should be loaded into the system. Simulation results based on a detailed model of metal-working manufacturing facility are presented.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.64-71
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• 2016

This paper proposes nonlinear behavior in a love model for Romeo and Juliet with an external force of discontinuous time. We investigated the periodic motion and chaotic behavior in the love model by using time series and phase portraits with respect to some variable and fixed parameters. The computer simulation results confirmed that the proposed love model with an external force of discontinuous time shows periodic motion and chaotic behavior with respect to parameter variation.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.289-294
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• 2012

In this paper, the three-dimensional magnetic field created by non-periodic magnet arrays is calculated analytically. The analytical expression of the magnetic field is derived by using a magnetic charge model. The influence of ferromagnetic boundaries is formulated with an image method. Finally, we compare the results determined by analytical calculations to those from a finite element simulation.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.644-645
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• 2007

In this paper, the eigenvalue sensitivity analysis algorithm in discrete systems by the RCF method are presented and applied to the power system including TCSC. The RCF analysis method enabled to precisely calculate eigenvalue sensitivity coefficients of dominant oscillation modes after periodic switching operations. These simulation results are very different from those of the conventional continuous system analysis method such as the state space equation method

• Proceedings of the Korea Society for Simulation Conference
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• 2003.06a
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• pp.129-134
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• 2003

In this paper, we determine optimal reduction in the lead time and setup cost for some stochastic inventory models. And we propose more general model that allow the backorder rate as a control variable. We first assume that the lead time demand follows a normal distribution. And we assume that the backorder rate is dependent on the length of lead time through the amount of shortages. The stochastic models analyzed in this paper are the classical continuous and periodic review policy models with a mixture of backorders and lost sales. For each of these models, we provide a sufficient conditions for the uniqueness of the optimal operating policy. We also develop algorithms for solving these models and provide illustrative numerical examples.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.602-603
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• 2007

In this paper, the RCF method is applied to analyze small signal stability of power systems including thyristor controlled FACTS equipments such as SVC. The eigenvalue sensitivity analysis algorithm in discrete systems by the RCF method are presented and applied to the power system including SVC. As a result of simulation, the RCF analysis method is very powerful to calculate the newly generated unstable oscillation modes precisely after periodic switching operations of SVC. Also the RCF analysis method enabled to precisely calculate eigenvalue sensitivity coefficients of dominant oscillation modes after periodic switching operations. These simulation results are very different from those of the conventional continuous system analysis method such as the state space equation method.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1346-1353
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• 2017

The FISPACT-II inventory simulation platform is a modern computational tool with advanced and unique capabilities. It is sufficiently flexible and efficient to make it an ideal basis around which to perform extensive simulation studies to scope a variety of responses of many materials (elements) to several different neutron irradiation scenarios. This paper briefly presents the typical outputs from these scoping studies, which have been used to compile a suite of nuclear physics materials handbooks, providing a useful and vital resource for material selection and design studies. Several different global responses are extracted from these reports, allowing for comparisons between materials and between different irradiation conditions. A new graphical output format has been developed for the FISPACT-II platform to display these "global summaries"; results for different elements are shown in a periodic table layout, allowing side-by-side comparisons. Several examples of such plots are presented and discussed.