• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.673-676
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• 2007

These days, the damage of noise has increased seriously by rapid change of life style because of the centralization of urban population, and the rapid increase of traffic. The Ministry of Environment has emphasis on the systematic management about the noise of daily life and the close connection of daily noise management policy with relevant ministries, and put into practice "the master plan of lessening the noise of daily life" from year 2006. This study tried to find out the reduction methods and the effective management of railway noise in the action plan of railway part of "the master plan of lessening the noise of daily life". According to this study, railway noise can be reduced greatly by taking action of railway detail plans. The cause of railway noise varies by rolling stock, track and more, so the reduction methods of railway noise can be studied specially, scientifically and constantly in every field.

• Journal of the Korean housing association
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• v.13 no.3
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• pp.103-113
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• 2002

The purpose of this study is to find out the characteristics of users'behavior for the planning of the shared community space(SCS). It was analyzed and estimated that the present status of the SCS of the contemporary multi-family housing sites in Korea and the residents'behavior in the SCS. Theoretic investigation and empirical research methods were used in this study. The empirical survey focused on seeking out user-oriented design criteria, based on the analysis of residents'usage behavior for the SCS. The analysis was made by both quantitative and qualitative methods. The results of this study are as follows; First, as to the usage status survey for the SCS, there is a difference in the degree of usage according to their locations. Second, as to the analysis of the SCS through a mental map, the sketch map analysis is found to be a useful research method for the SCS planning by actualizing the residents'behavior characteristics. In detail, the main characteristics in the SCS planning are nearness, centrality, intimacy, combination of facilities and the connection with the main paths of the complex.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.266-270
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• 2008

Bluetooth technology provides a way to connect and exchange information between personal devices over a secure and short-range radio frequency without any authentication infrastructures. For this infrastructure-less feature, Bluetooth has several problems which could not occur in other network, and among them location tracking attacks is essential problem which should be solved. In this paper, we introduce the location tracking attack and propose an anonymous connection protocol against it. We also perform security analysis based on possible scenarios of this attack, and estimate both execution time and memory spaces of our scheme and existing methods.

• The Journal of Information Systems
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• v.9 no.1
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• pp.27-44
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• 2000

The structure of neural networks is represented by a weighted directed graph with nodes representing units and links representing connections. Each link is assigned a numerical value representing the weight of the connection. In learning process, the values of weights are adjusted by errors. Following experiment results, the interval of adjusting weights, that is, epoch size influenced neural networks＇ performance. As epoch size is larger than a certain size, neural networks＇performance decreased drastically. And the number of hidden layer＇s node also influenced neural networks＇performance. The networks＇performance decreased as hidden layers have more nodes and then increased at some number of hidden layer＇s node. So, in implementing of neural networks the epoch size and the number of hidden layer＇s node should be decided by systematic methods, not empirical or heuristic methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.767-772
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• 2018

Recently, some meta-heuristic algorithms, such as GA(Genetic Algorithm) and GP(Genetic Programming), have been used to optimize CNN(Convolutional Neural Network). The CNN, which is one of the deep learning models, has seen much success in a variety of computer vision tasks. However, designing CNN architectures still requires expert knowledge and a lot of trial and error. In this paper, the recent attempts to automatically construct CNN architectures are investigated and analyzed. First, two GA based methods are summarized. One is the optimization of CNN structures with the number and size of filters, connection between consecutive layers, and activation functions of each layer. The other is an new encoding method to represent complex convolutional layers in a fixed-length binary string, Second, CGP(Cartesian Genetic Programming) based method is surveyed for CNN structure optimization with highly functional modules, such as convolutional blocks and tensor concatenation, as the node functions in CGP. The comparison for three approaches is analysed and the outlook for the potential next steps is suggested.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.39-45
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• 2010

This paper deals with investigation on the spot for grounding systems of buildings based on international standards at construction sites. The investigation was carried out for grounding method, grounding type, shape of grounding electrode, grounding for a lightning protection system, continuity of steelwork in reinforced concrete structures, etc. The investigation on the spot was performed by a researcher and engineer with over fifteen years of industry experience all over the country. As a result of the investigation on the spot in 13 buildings, common grounding and structure grounding methods were dominant. The safety improvement methods include installation of equipotential bonding conductors for the connection to the main earthing terminal, equipotential bonding conductors for supplementary bonding, use of Surge Protective Devices (SPD), and safe connections between earthing conductors and the rebar.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.194-202
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• 2022

The use of public Wi-Fi has increased in recent years with many people like to spend their time outside in malls or café shops which provide public Wi-Fi for their customers. However, since the public Wi-Fi can be accessed from any device the security of public Wi-Fi plays a big role to prevent the stealing of information by an attacker with methods and techniques such as WPA, WPA2 and WPA3. However, it is well known to the attackers that these methods are not difficult to get hacked by the attacker device to take the client precious information. Some researches were done in increasing the security of public Wi-Fi each with their own different technique or algorithm to provide more secure connection to the public Wi-Fi and prevent any unauthorized user to connect to avoid stealing the data of another legal user. Theses research paper are evaluated to learn which method excel in protecting the public Wi-Fi security by giving an analysis to the methods provided by the research paper with comparing the pros and cons of each algorithm. Moreover, the research displays that there are methods to actually provide security to the public Wi-Fi with each being very different in implementation.

• Toxicological Research
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• v.1 no.1
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• pp.17-30
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• 1985

Mycotoxins are a group of toxicants giving a risk potential to human health in connection with the daily food intake. Food commodities once contaminated with mycotoxins can not be detoxified by any economic means and prevention was suggested as the only measure. In order to minimize the economic loss and health hazard posed by mycotoxins and toxicoses, systematic and toxicological studies on the subject should be undertaken. Most reports in Korea were concentrated on the mycological studies of relatively easy techniques and the confirmation or quantitation of mycotoxins was rarely done. Research topics to be undertaken in future may be exemplifid below: (1) Establishing assay methods for individual or multi-residue of mycotoxins (2) Monitoring of mycotoxins for suspicious food or feed samples in Korea (3) Epidemiological survey of mycotoxicoses (4) Etiological survey of disease outbreaks associated with mycotoxins (5) Accumulation of testing method and data on the toxicity of mycotoxins (6) Legal regulation to control mycotoxins and development of their detoxification / elimination methods

• Journal of Power Electronics
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• v.15 no.1
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• pp.278-287
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• 2015

This paper proposes a novel voltage distortion approach for output filter design based on the voltage transfer function for both off-grid and grid-connected Pulse Width Modulation (PWM) Inverters. The method explained in detail is compared to conventional methods. A comparative analysis is performed on an example of L and LCL-filter design. Simulation and experimental results for the off-grid and the grid-connected single phase inverter prove our theoretical predictions. It was found that conventional methods define redundant values of the output filter elements. Assumptions and limitations of the proposed approach are also discussed.

• Wind and Structures
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• v.21 no.6
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• pp.657-675
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• 2015

In this study, the feasibility of vibration-based damage detection methods for the wind turbine tower (WTT) structure is evaluated. First, a frequency-based damage detection (FBDD) is outlined. A damage-localization algorithm is visited to locate damage from changes in natural frequencies. Second, a mode-shape-based damage detection (MBDD) method is outlined. A damage index algorithm is utilized to localize damage from estimating changes in modal strain energies. Third, a finite element (FE) model based on a real WTT is established by using commercial software, Midas FEA. Several damage scenarios are numerically simulated in the FE model of the WTT. Finally, both FBDD and MBDD methods are employed to identify the damage scenarios simulated in the WTT. Damage regions are chosen close to the bolt connection of WTT segments; from there, the stiffness of damage elements are reduced.