• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.583-590
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• 2014

The purpose of this study is to analyze and compare the life cycle cost of window glass with insulation film and regular glass, to verify an economical window construction method. As an approach method, the thermal performance data of each type of glass was measured using Window 6.3 and ECO2-OD Simulation Program, applied it to the case building to calculate the air conditioning and heating maintenance costs and LCC, and compared the economic feasibility. As a result, installing an additional insulation film prevents the solar heat penetration in the summer, so it reduces the cooling cost, on the other hand, it increased heating cost in winter. From the life cycle cost perspective, the effect of cooling cost reduction does not counterbalance the increase in heating cost and the additional cost from film installation and repair; therefore, the installation of insulation film may not be a proper method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.93-101
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• 2010

In this paper we generate Gold-sequence by using M-sequence which is made by two primitive polynomial of GF(2). Generally M-sequence is generated by linear feedback shift register code generator. Here we show that this matrix of appropriate permutation has Hadamard matrix property. This matrix proves that Gold-sequence through two M-sequence and additive matrix of one column has one of major properties of Hadamard matrix, orthogonal. and this matrix show another property that multiplication with one matrix and transpose matrix of this matrix have the result of unit matrix. Also M-sequence which is made by linear feedback shift register gets Hadamard matrix property mentioned above by adding matrices of one column and one row. And high-speed conversion is possible through L-matrix and the S-matrix.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.245-253
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• 2010

The present study shows some results of developing evaporative heat exchangers with mini-channels. Heat exchangers with three different water paths were manufactured and tested to compare performances of cooling and pressure drop. Among the three types of heat exchangers, Type 2 with full-etching was proved to be the best in the cooling performances for considered operating conditions, and thus it is recommended to adopt Type 2 for its simplicity of production and outstanding performance. However, Type 1 was shown to be better when it is operated at a high air inlet temperature condition. The developed evaporative heat exchanger will be installed in Environmental Control Systems(ECSs) for aerial vehicles, and it can be used effectively in case an ECS is not only limited in its weight and volume but also required to absorb heats without supplying water (or a coolant) for a certain period of time.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.313-319
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• 2014

Additional train scheduling is often required to increase the capacity of transporting passengers or freight. In most previous studies on scheduling additional trains, operation time of the added train is designated first; and then the train operation feasibility is examined. However, it is often difficult to apply this approach to domestic trains because the density of the railroad network in Korea is high and various types of trains are in use. Moreover, for freight trains, it is even more challenging because the delay is accumulated due to lower priority whenever a freight train and a passenger train contend for a common segment of rail. In this paper, we address the additional train scheduling problem which entails finding a feasible schedule for an additional train having a fixed departure time or departure time windows. The problem is modeled as a mixed integer programming and a column generation technique is used to solve it.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.317-324
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• 2006

In this paper, we propose a new indexing technique to solve various queries which have a strong good point not only database indexing schema take advantage of converting from semi-structured data to structured data but also performance is more faster than before. We represent structure information of XML document between nodes of tree that additional numbering information which can be bit-stream without modified structure of XML tree. And, We add in indexing schema searching incidental structure information in the process. In Querying schema, we recover ancestor nodes through give information of node using indexing schema in complete path query expression as well as relative path query expression. Therefore, it takes advantage of making derivative query expression with given query. In this process, we recognize that indexing and querying schema can get searched result set faster and more accurate. Because response time is become shorter by bit operating, when query occur and it just needs information of record set earch node in database.

• Plant Journal
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• v.18 no.2
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• pp.32-40
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• 2022

In this study, we investigated the operation data of combined heat and power in accordance with the change of the inlet guide vane with partial load. The partial load 80% could close the inlet guide vane up to 24%, and the exhaust gas temperature could be increased by 52℃. The partial load 90% could close the inlet guide vane up to 12%, and the exhaust gas temperature could be increased by 23℃. At 80% of partial load with the thermal load tracking mode, the output could be increased up to 5.68 MW, the combined cycle efficiency increased by 0.73%, and the combined heat and power efficiency increased by 1.81%. At 90% of the partial load, the output could be increased up to 2.55 MW, the combined cycle efficiency increased by 0.32%, and the combined heat and power efficiency increased by 0.72%.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.651-658
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• 2012

This paper concentrates on the evaluation of microcracks in thermal damaged concrete on the basis of the nonlinear ultrasonic modulation technique. Since concrete structure exposed to high temperature accompanies the development of microcracks due to the physical and chemical changes from temperature and exposed time, the adoption of nonlinear approach is required. Instead of using the conventional ultrasonic nondestructive methods which have the limitation in evaluating excessive microcracks, accordingly, a nonlinear ultrasonic modulation method which shows better sensitivity in quantifying microcracks is introduced. Upon the analysis for the modulation of ultrasonic wave and low frequency impact to measure the nonlinearity parameter, which can be used as an indicator of thermal damage, the verification processes for the introduced technique are followed: SEM investigation and permeable pore space test are performed to characterize thermally induced microcracks in concrete, and ultrasonic pulse velocity tests are performed to confirm the outstanding sensitivity of nonlinear ultrasonic modulation technique. In advance, compressive strength of thermal damaged concrete is measured to represent the effect of microcracks on performance degradation. Correlation studies between experimental data and measured data show that nonlinear ultrasonic modulation technique can effectively be used to quantify thermally induced microcracks, and to estimate the compressive strength of thermally damaged concrete.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.393-400
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• 2018

The purpose of this study was to empirically investigate the emotional dynamics among sport issues, social structure changes and collective behaviors with time-series analysis. For the purpose, the doping scandal of Tae-Hwan Park was chosen and simplified into 10 episodes. And replies and articles on them were analysed by time-series analysis. As the conclusions, first, there was a clear causal relationship between sport issue and sport emotion. Second, sport emotion was a social being which interacting with social process. Third, the sport emotional dynamics was confirmed. With this study, the sport emotion dynamics was empirically verified, but more statistical approaches would be needed for stronger evidences.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.13-19
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• 2017

The use of ultrasonic surgery units and scalers are steadily increasing in the field of dentistry. Such units and scalers should be evaluated before they are commercialized because the mechanical performance and stability of equipment is crucial for patients. Hence, we created a hand-piece moving system that can test bone cutting and teeth scaling. The purpose of this study was to evaluate the teeth scaling performance of ultrasonic scaler unit. Additionally, we measured the temperature distribution and noise during the test. through an experimental test, we found that a high output of an Ultrasonic NX device can cause serious damage to the teeth surface, and it was not within range in heat generation distribution and noise test.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1121-1130
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• 2004

This paper proposes a method for line and word segmentation for machine-printed text blocks. To separate a text region into the unit of lines, it analyses the horizontal projection profile and performs a recursive projection profile cut method. In the word segmentation, between-word gaps are identified by a hierarchical clustering method after finding gaps in the text line by using a connected component analysis. In addition, a special symbol detection technique is applied to find two types of special symbols tying between words using their morphologic features. An experiment with 84 text regions from English and Korean documents shows that the proposed method achieves 99.92% accuracy of word segmentation, while a commercial OCR software named Armi 6.0 Pro$^{TM}$ has 97.58% accuracy.y.