• Journal of Advanced Marine Engineering and Technology
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• v.27 no.1
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• pp.24-32
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• 2003

The PID controller has been widely used in industrial applications due to its simple structure and robustness. Even if it is initially well tuned, the PID controller must be retuned to maintain acceptable performance when there are system parameter changes due to the change of operation conditions. In this paper, a self-tuning control scheme which comprises a parameter estimator, a NN-based rule emulator and a PID controller is proposed, which can cope with changing environments. This method involves combining neural networks and real-coded genetic algorithms(RCGAs) with conventional approaches to provide a stable and satisfactory response. A RCGA-based parameter estimation method is first described to obtain the first-order with time delay model from over-damped high-order systems. Then, a set of optimum PID parameters are calculated based on the estimated model such that they cover the entire spectrum of system operations and an optimum tuning rule is trained with a BP-based neural network. A set of simulation works on systems with time delay are carried out to demonstrate the effectiveness of the proposed method.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.58
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• pp.287-311
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• 2013

In this study, the scope of previous logistics security were focused only on port and ship. Because of it now extends to the overall (export and import) supply chain areas and in regards with supply security programs in the international level, it reviewed supply chain security programs categorized them into 'ships and port security system', 'container screening system', 'logistics chain authorization system' which are expanded to be adopted in the international level. The major features of those programs are summarized as in building risk management system, providing information ahead, selectivity test and benefits to AEO authorized companies in the customs administration level. The government and companies which are to ensure supply chain security and trade facilitation in order to cope actively with international customs administrative atmosphere need to do the followings : First, they need to build an intra-government integrated supply chain security and make efforts to conclude AEO MRA in order to increase trade competitiveness among major trading countries. Second, they need to build supply chain risk management system in order to enhance management performance through overseas market and company level strategy to obtain and maintain AEO authorization in the company level.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.62-64
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• 2010

Since 1990 in South Korea, the considerable concern for the safety of construction sights has been increased due to serious accidents. There have been numerous big improvements in preventing the accidents by strengthening legal enforcement and by continuing to emphasize the safety management. Further, the safety standards and criteria for temporary constructional work have been enacted and established in order to maintain safe work environments in temporary construction and structure settings. However, the death rate from fall accidents is still high in the temporary constructional and structural settings in comparison to other work places in construction. According to the analysis of accidents in the field of construction between 2000 and 2007, the death rate from fall accidents in the temporary constructional settings was highest. In addition, there have been more fall accidents in the work setting by small or medium construction enterprises rather than large enterprises due to the relative lack of the safety management. Thus, in this study, the analysis of the causes of fall accidents in the temporary constructional and structural settings between 2000 and 2007 was conducted. Moreover, a survey study was carried out in order to investigate further causes based on the analysis. Finally, this study was also conducted in order to provide basic information and knowledge about the prevention of future accidents.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.3
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• pp.143-151
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• 2009

This paper starts with the assumption that in order for the popularization of hanbok leading to greater interest among the public for Hanbok and its uses in everyday life, the period for Hanbok events each year must be solidified, making it a standardized provide opportunities for participation regardless of demographic. Globalization of Hanbok most occur through a combination of related academic fields, division of roles in fields of expertise, and a scientific understanding of Hanbok. Thus various Hanbok-related programs such as contests, fashion shows, experience centers and exhibitions should be provided in one unified setting. Government sponsored Hanbok cultural events have generally been aimed at foreigners or foreign human residency, while events in Korea hae generally been carried out by a more diverse rage of groups, making it difficult for the general population to obtain information or participate actively. In order for hanbok to maintain its tradition as the national costume of Korea, Long-term develop plans must be set. Along with popularization in order to bring hanbok into everyday life, methods for the globalization of hanbok must be explored, providing opportunities to spotlight the diversity and characteristics of Korean costumes, in various events which promote participation, festival-forming and globalization of hanbok culture considering elements such as time (yearly, monthly etc.) and audience (age group, social level etc.).

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.11
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• pp.483-493
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• 2002

The damping ratio ${\xi}$ of the unit-step response of a second-order discrete system is a function of only the location of the closed-loop poles and is not directly related to the location of the system zero. However, the peak overshoot of the response is the function of both the damping ratio ${\xi}$ and an angle ${\alpha}$, which is the phasor angle of the damped sinusoidal response and is determined by the relative location of the zero with respect to the closed-loop poles. Therefore, if the zero and the open-loop poles are relatively adjusted, through pole-zero cancellation, to maintain the desired (or designed) closed-loop poles, the damping ratio ${\xi}$ will also be maintained, while the angle ${\alpha}$ changes. Accordingly, when the closed-loop system poles are fixed, the peak overshoot is considered as a function of the angle ${\alpha}$ or the system zero location. In this paper the effects of the relative location of the zero on the system performance of a second-order discrete system is studied, and a design method of digital compensator which achieves a minimum peak overshoot while maintaining the desired system mode and the damping ratio of the unit step response is presented.

• Korean Security Journal
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• no.3
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• pp.306-335
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• 2000

The desires for safety of body and life can be said to be fundamental and natural in human beings. But the rapid industrialization and urbanization phenomena in our modern society is accelerating the treand for increasing diverse social pathology. Rise of serious crimes such as robbery and rape has already become an especially serious social problem and is at the point of threatening our welfare and social order. But the police, which is primarily responsible for the maintenance of welfare and social order of the public, is unable to respond actively to the increasing demand for policing due to the lack of available manpower and overwork. Thus, the purpose of this thesis is to look for a plan to actively respond to the daily increasing outcry for law and order so that the public may maintain safe and happy lifestyles without the threat of crime. One concrete and practical strategy is to resolutely separate and transfer some of the many functions of the police that can be handled by citizen organizations to those groups so that the police can be relied upon to become functionally efficient. This will decrease the work of the police, thereby allowing the police to concentrate on its inherent responsibilities. As its primary example, 'transferring the function of security' of the police to the private security industry is suggested in this thesis.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.158-166
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• 2005

Pressurized gas pipeline is subject to harmful effects both of the surrounding environment and of the materials transmitted in them. In order to maintain the integrity, reliable assessment procedures including tincture mechanics analysis etc are required. Up to now, the integrity assessment has been performed using conventional deterministic approaches even though there are many uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for gas pipeline evaluation. The objectives of this paper are to estimate the failure probability of corroded pipeline in gas and oil plants and to propose limited operating conditions under different types of leadings. To do this, a probabilistic assessment program using reliability index and simulation techniques was developed and applied to evaluate failure probabilities of corroded API-5L-X52/X60 gas pipelines subjected to internal pressure, bending moment and combined loading. The evaluation results showed a promising applicability of the probabilistic integrity assessment program.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1074-1079
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• 1999

In this paper, the concept of puncturing is introduced to turbo code in order to implement various code as code rate varies.rates. First, several different puncturing matrices are applied into rate 1/3 encoder in order to produce various rate 1/2 turbo codes. By analyzing and comparing these results, we can show which puncturing pattern should be selected in order to maintain good performance. Second, we select some appropriate puncturing patterns which provide the best performance of turbo codes of various rates from 1/3 to 2/3 among all the possible candidates. Finally, we provide the change of required Eb/No at $P_b=10^{-4}$ as code rate varies.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.6
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• pp.37-48
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• 2003

A study for the structural strength evaluation of doubler plates subjected to the in-plane combined load and lateral pressure load has been performed through a systematic evaluation process. In order to properly estimate the static strength of doubler plate, elasto-plastic large deflection analysis is introduced including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed based on the analysis results. Also, in order to compare the doubler structure with the original strength of main plate without doubler, a simple formula for the evaluation of the equivalent flat plate thickness is derived based on the additional series analysis of fiat plate structure. Using this derived equation, the thickness change of a equivalent flat plate is analyzed according to the variation of various design parameters of doubler plate and some design guides are suggested In order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent plate thickness formula and the developed buckling strength formulas for intact plates by author et al. is discovered and these relations are formulated for the future development of simple strength evaluation formula of doubler plate structure.

• Korean Journal of Computational Design and Engineering
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• v.15 no.6
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• pp.449-459
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• 2010

Recently, not only marine PLM (Product Lifecycle Management) system but also an effective outfitting BOM (Bill of Material) management has been attracted by many shipyards. In particular, efficient outfitting design is being one of major issues in shipyards since most of currently designed marine vessels have more complex outfitting system than ever. Furthermore, each outfitting system has huge number of parts that should be arranged based upon the procurement and installation plan. Outfitting BOMs evolve into different forms according to the product development phases during basic design; detail design; and production design. Therefore, it is very difficult to maintain a consistent BOM data during the design phases. In order to express the evolution of product structures and the information of outfitting along the ship design, we suggested UID (Unique ID) code system. The UID (Unique ID) is used in order to create the relationship within evolutional BOMs of each design stage. It utilizes as the procedure of weight calculation for procurement BOM during each design stage. Thereafter, in order to demonstrate suggested outfitting BOM management technique, we suggested a prototype. In the prototype system, suggested features of outfitting BOM are implemented.