• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1870-1875
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• 2003

Optimization has been used in many engineering problems and must be one of the essential components during design process now. It is the process of maximizing the performance called an objective function of a system while satisfying some constraints, so finite element method is generally required in order to obtain these values during optimization. However, there are some difficulties to obtain them by means of FEM, where the changes of design variables cause the distortion and the regeneration of mesh that may result in inaccuracy and inefficiency. In order to overcome this problem, this paper proposed an alternative that the eXtended FEM introduced and developed by Ted Belytschko was applied to the optimization process because the key points of the X-FEM lie in that the discontinuity can be represented independently on the mesh by a function called in an enrichment function.

• Journal of Power Electronics
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• v.12 no.2
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• pp.242-248
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• 2012

Self oscillating current fed push pull resonant inverters can be controlled without using special drivers. Dc current flows through the choke coil and the power switches, although the driving signals of the power switches are sinusoidal. When the base current is near zero, the transistors cannot be operated in switching mode. Hence higher switching power losses and instantaneous peak power during off transitions are observed. In this study, an alternative design has been proposed to overcome this problem. A prototype circuit has been built which provides dc bias current to the base of the transistors. Experimental results are compared with theoretical calculations to demonstrate the validity of the design. The proposed design decreases the peak and average power losses by about 8 times, when compared to conventional designs.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.87-94
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• 2000

The introduction of an ERP(Enterprise Resource Planning) system for the competitive enterprise has been late because of a great cost. In this paper, we design and implement ERP application service as an alternative proposal of an ERP system for medium and small enterprises. Unlike most of previous works that show only the implementation of their ERP application, this approach provides the design model of an suitable environments for medium and small enterprises.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.5
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• pp.222-238
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• 2008

In this paper, the random key pre-distribution scheme introduced in ACM CCS'02 by Eschenauer and Gligor is reexamined, and a generalized form of key establishment is introduced. As the communication overhead is one of the most critical constraints of any successful protocol design, we introduce an alternative scheme in which the connectivity is maintained at the same level as in the original work, while the communication overhead is reduced by about 40% of the original overhead, for various carefully chosen parameters. The main modification relies on the use of a two-level key pool design and two round assignment/key establishment phases. Further analysis demonstrates the efficiency of our modification.

• Journal of the Korea Furniture Society
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• v.12 no.1
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• pp.131-142
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• 2001

Cultural needs of human have grown enormously. Consumer trend and individual taste have become more individualistic and diversified. Efforts to improve the quality of life have changed the concept of lift space as well as the concept of interior life supplies. Products are no longer standardized and produced in massive scale, thus a shift of value has risen. Damages done by the economical development have made consumers take interests in products that are more natural and in harmony with human beings. It is a tendency that wooden materials are becoming a preference as a specific alternative. There is a great social change with a new paradigm like this. Considering the change, we propose a new vision and activation plan on design development of wooden products through specific and practical studies by the system of educational and industrial cooperation which is an organic association system for developing human resources of educational system and producing profits of industry. From it, we can expect great effects as a competitive design of coming future.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.940-956
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• 2004

In the course of studying the design of securing the 100-year-long durability of 100 years the subway structure according to the requested service by the Seoul Metropolitan Subway Construction Headquarters, we analyzed 14 construction sites adopting the durability design in subway line No. 9 and concluded as follows: 1. When comparing with 158, the environment index presented for securing 100-year-long durability of subway structure in subway line No. 9, the index of durability was verified as 159.7$\~$179.8 2. When examining the increase value of durability index, we verified that the constructors didn't make various choices in method but they employed the uniformly selected system. 3. Under consideration of the bid form, the construction under bid contract in bulk gave the impacts on the construction cost with attention to selection of the durability index, while the construction under alternative contract in bid adopted uniformly the standard presented by the ordering party.

• ETRI Journal
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• v.34 no.2
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• pp.284-287
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• 2012

Quantum-dot cellular automata (QCA) is one of the few alternative computing platforms that has the potential to be a promising technology because of higher speed, smaller size, and lower power consumption in comparison with CMOS technology. This letter proposes an optimized full comparator for implementation in QCA. The proposed design is compared with previous works in terms of complexity, area, and delay. In comparison with the best previous full comparator, our design has 64% and 85% improvement in cell count and area, respectively. Also, it is implemented with only one clock cycle. The obtained results show that our full comparator is more efficient in terms of cell count, complexity, area, and delay compared to the previous designs. Therefore, this structure can be simply used in designing QCA-based circuits.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.517-526
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• 2016

In this paper, some popular intensity measures of earthquakes including magnitude, MMI, and PGA as well as their empirical relationships are briefly reviewed since they have been widely used without prudence by mass media, the public, and even the government when asking or expressing the seismic capacity of buildings. The basic concept of current seismic design is also presented in order to facilitate relevant discussions. It is emphasized that expressing the building seismic capacity simplistically in terms of seismological quantities or terminologies like magnitude and MMI is inherently irrational, may be misleading the stakeholders, and should be avoided. Alternative expressions, more rational and consistent with current seismic design philosophy and practice, are recommended.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.123-131
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• 2005

Semantic object model has widely been recognized as an alternative data modeling approach to entity-relationship model for database system design. In this study, we have presented a semantic object model for intermediary type shopping mall consisting of multiple buyers and sellers. Essential processes and information with regard to the customer management, product management, price estimation, product order etc. have been considered for this study. Upon careful examination and analysis of them, a detailed semantic objects and attributes have been drawn and structured into semantic object diagrams. The final objects were converted into an entity-relationship diagram so that intuitive comparison could be made for relational database design. The results in this study may form a conceptual framework for both academic concerns and more complicated system applications.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.10a
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• pp.315-321
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• 2001

Since 1984, block-type reinforced earth wall with geogrid reinforcement has been widely used for retaining wall applications till now in Korea. The use of geogrid as a reinforcement in the reinforced earth wall is steadily increased in an amount over 1,500,000㎡ in a year However, still need exists that some problems in design and construction practices should be made to review, Therefore, this paper reviewed reasonable criteria for selection of backfills, design details considering the effect of the upper soil slope on reinforced earth wall, horizontal displacement of facing block during compaction, and the damage of geogrid reinforcements on the edge part of facing block. Finally, alternative methods of measures on those problems are proposed.