• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.57-72
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• 1999

With the rapidly increasing complexity of decision-marking or system development in the fields of industry, management, etc., modelling techniques using simulation has become more highlighted. Particularly, the advent of parallel computer systems not only has opened a new horizon of parallel simulation, but also has greatly contributed to the speed-up of the execution of simulation. The implementation of parallel simulation, however, is not a easy job for those who accustomed to the existing computer systems. And it is also necessarily confronted with the problem of synchronization conflict in the process. Thus, how to allow a wider community of users to gain access to parallel simulation while solving synchronization conflicts has become an important issue in simulation study. As a method to solve these problems, this paper is primarily concerned with the implementation of GPSS which is a generally used simulation language for discrete event simulation, onto a parallel computer using C-LINDA. For that, this paper, is to suggest a model and algorithm and to experiment it using a case.

• ETRI Journal
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• v.42 no.5
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• pp.799-804
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• 2020

Network security situation prediction is difficult due to its strong uncertainty, but DS evidence theory performs well in solving the problem of uncertainty. Based on DS evidence theory, this study analyzed the prediction of the network security situation, designed a prediction model based on the improved DS evidence theory, and carried out a simulation experiment. The experimental results showed that the improved method could predict accurately in the case of a large conflict, and had strong anti-jamming abilities as compared with the original method. The experimental results prove the effectiveness of the improved method in the prediction of the network security situation and provide some theoretical basis for the further application of DS evidence theory.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.5
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• pp.356-361
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• 2000

The radial position of OiSF-ring has been meaningful data in industry. Thus it's position was calculated by application of (V/G)/sub crit/ = 0.138 ㎟/minK and point defect dynamics for industrial scale grower with various pull rates. After the calculation, compared with experimental result. OiSF-ring diameters expected with calculation were good agreement with experimental results. In order to show validity of the predicted temperature distribution using STHAMAS which is one of the global simulator for Cz crystal growing, temperature was measured along the axis of crystal using thermocouples, and compared with the calculated temperature. We found the effective thermal conductivity K/sub m/ (r) which gives in accordance with the temperature distribution at the axis of crystal and crystal/melt interface shape between experimental and computational results. Therefore, effective thermal conductivity K/sub m/ (r) was applied instead of solving melt convection problem.

• Asia pacific journal of information systems
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• v.9 no.1
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• pp.143-163
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• 1999

This study investigates the effect of group size on group performance, here the quality of group decision, Four effects are proposed and tested in a field experimental setting : (1) the relationship between the group size and the distribution of individual's problem-solving ability ; (2) the change of the group decision quality as group size increases ; (3) the relationship between the group decision quality and the quality of the best/worst member as group size increases ; (4) the relationship between the group decision quality and the average quality of individuals in the group as group size increases. Data showed that contrary to the exiting results, group decision quality was not improved with the group size. Rather, it showed a little tendency that group decision quality was worsened with the group size. Data also showed that consensus-oriented group decision making process produced the compromised output. Thus, group decision quality was not better than the average group members'. The opinion of the best member was not accepted. The implications of the findings are discussed for the development of a Korean GSS.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1650-1658
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• 2018

Multilevel converters are being widely used in medium-voltage high-power applications including motor drive systems, utility power transmission, and distribution systems. Selective harmonic elimination (SHE) is a well-known modulation method to generate high quality output voltage waveforms. This paper presents a new simple practical method for generating a generalized five-level waveform without selected low order harmonics. This method is based on a phase-shifted expression for the SHE problem, which can analytically calculate the exact values of switching angles and the feasible modulation index range for three-level and five-level waveforms. The proposed method automatically determines the number of transitions between levels and generates proper output waveform without solving complex trigonometric equations. Due to the simplicity of the computational burden, the real-time implementation of the proposed algorithm can be performed by a simple processor. Simulation and experiment results verify the correctness and effectiveness of the proposed method.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.343-348
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• 2023

As the IoT market continues to grow, security threats to IoT devices with limited resources are also increasing. However, the application of security technology to the existing system to IoT devices with limited resources is impossible due to the inherent characteristics of IoT devices. Various methods for solving related problems have been studied in existing studies to solve this problem. Therefore, this study analyzes the characteristics of domestic IoT authentication standards and existing research to propose an algorithm that applies blockchain-based authentication and lightweight encryption algorithms to IoT equipment with limited resources. In this study, a key generation method was applied using a Lamport hash-chain and data integrity between IoT devices were provided using a Merkle Tree, and an LEA encryption algorithm was applied using confidentiality in data communication. In the experiment, it was verified that the efficiency is high when the LEA encryption algorithm, which is a lightweight encryption algorithm, is applied to IoT devices with limited resources.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.248-254
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• 1993

This paper proposes the labeling method for solving bin-picking problem in robot vision. It has the processing steps such as image thresholding, region labeling, and moment computation. To determine a target object from object, the modified labeling method is used to. The moment concept applied to determine the position and orientation of target object. Finally, some experiment result are illustrated and compared with the results of conventional shrinking algorithm and collision fronts algorithm. The proposed labeling method has reduced processing time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.212-219
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• 2012

This study focus on what methods of MOT are needed and utilized to solve a technical problem in the MOT leading company. We first classified the MOT methods by project life cycle and R&D job quality based on the several discussion with working group. In order to study, the survey was carried out by 168 experts working on MOT practices. Our main research findings are as follows. The level of utilized MOT methods was above average because MOT sector was beginning to represent an increasing share of total R&D business. But the satisfaction level on the MOT majors was below average. The more utilized MOT methods in practices were 'environment analysis and opportunity research,' 'business feasibility,' 'roadmapping,' 'portfolio,' 'technology tree,' 'scheduling,' 'risk management,' 'six sigma,' 'design of experiment,' 'quality control,' 'cost analysis' etc. And the subjects of product realization process were also needed to MOT practice such as 'design for reliability,' 'design for cost,' 'design for performance,' 'design for safety' deeply involved to product quality. Finally, the capability requested to University students were 'problem define and solving,' 'technology planning and strategy,' 'creative thinking.'

• School Mathematics
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• v.10 no.2
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• pp.181-197
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• 2008

Bertrand's Paradox is known as a paradox because it produces different solutions when we apply different method. This essay analyzed diverse problem solving methods which result from no clear presenting of 'random chord'. The essay also tried to discover the difference between the mathematical calculation of three problem solvings and physical experiment in the real world. In the process for this, whether geometric statistic teaching related to measurement and integral calculus which is the basic concept of integral geometry is appropriate factor in current education curriculum based on Laplace's classical perspective was prudently discussed with its status.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2547-2567
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• 2021

It has been widely acknowledged that occlusion impairments adversely distress many face recognition algorithms' performance. Therefore, it is crucial to solving the problem of face image occlusion in face recognition. To solve the image occlusion problem in face recognition, this paper aims to automatically de-occlude the human face majority or discriminative regions to improve face recognition performance. To achieve this, we decompose the generative process into two key stages and employ a separate generative adversarial network (GAN)-based network in both stages. The first stage generates an initial coarse face image without an occlusion mask. The second stage refines the result from the first stage by forcing it closer to real face images or ground truth. To increase the performance and minimize the artifacts in the generated result, a new refine loss (e.g., reconstruction loss, perceptual loss, and adversarial loss) is used to determine all differences between the generated de-occluded face image and ground truth. Furthermore, we build occluded face images and corresponding occlusion-free face images dataset. We trained our model on this new dataset and later tested it on real-world face images. The experiment results (qualitative and quantitative) and the comparative study confirm the robustness and effectiveness of the proposed work in removing challenging occlusion masks with various structures, sizes, shapes, types, and positions.