• Bulletin of the Korean Mathematical Society
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• v.47 no.3
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• pp.653-661
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• 2010

Let R be a ring, and let $\Psi$(R) be the ideal generated by the set {x $\in$R | 1 + sxt $\in$ R is unit-regular for all s, t $\in$ R}. We show that $\Psi$(R) has "radical-like" property. It is proven that $\Psi$(R) has stable range one. Thus, diagonal reduction of matrices over such ideal is reduced.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.667-672
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• 2013

This paper presents the development of a condition monitoring system that monitors the operating conditions of a reduction unit, such as the bearing temperature, gearbox vibration, and gear oil deterioration, and notifies the operator of potential problems or abnormal conditions. A series of field tests on high-speed rail and conventional lines was performed to identify the characteristics of temperature rise and vibration levels on the reduction unit during operation. The monitoring system was designed based on the proper sensor selection, measurement method, and signal analysis to optimize the interface with the operating system of high-speed trains. Application of this monitoring system to high-speed trains will play an important role in their proper maintenance and safe operation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.336-342
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• 2018

Noise reduction is an important issue in auxiliary power unit(APU) of tracking equipments for using military. In this study, we designed and tested reduction methods of structure borne noise and airborne source noise at the auxiliary power unit. From the bench test results, it is found that the effect of noise reduction is about 22 dB(A) if the silencer is redesigned, which is the rescue structure. However, the influence of noise reduction by air is insufficient. In addition, it is confirmed that the effect of noise reduction is excellent when structure borne noise reduction is applied to the vehicle. We expected that the test results of this study are used as basic data to reduce the noise of other tracking equipment developed later.

• ETRI Journal
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• v.23 no.4
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• pp.168-176
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• 2001

This paper discusses two important issues of corpus-based synthesis: synthesis unit generation based on phrase break strength information and pruning redundant synthesis unit instances. First, the new sentence set for recording was designed to make an efficient synthesis database, reflecting the characteristics of the Korean language. To obtain prosodic context sensitive units, we graded major prosodic phrases into 5 distinctive levels according to pause length and then discriminated intra-word triphones using the levels. Using the synthesis unit with phrase break strength information, synthetic speech was generated and evaluated subjectively. Second, a new pruning method based on weighted vector quantization (WVQ) was proposed to eliminate redundant synthesis unit instances from the synthesis database. WVQ takes the relative importance of each instance into account when clustering similar instances using vector quantization (VQ) technique. The proposed method was compared with two conventional pruning methods through objective and subjective evaluations of synthetic speech quality: one to simply limit the maximum number of instances, and the other based on normal VQ-based clustering. For the same reduction rate of instance number, the proposed method showed the best performance. The synthetic speech with reduction rate 45% had almost no perceptible degradation as compared to the synthetic speech without instance reduction.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.162-169
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• 2012

Our country set the mid-term reduction goal of greenhouse gases up to 2020 in accordance with Bali roadmap agreed in 2007 through the negotiation with UNFCCC in 2009 and specified the proper goal as by the Basic Act on Green Growth that went into effect at April, 2010. First of all the enlargement of green building construction has been suggested as a worldwide strategy to achieve the green house gas reduction. Building area is one of most important sectors for the countermeasure of climate change agreement and the achievement of national green house gas reduction goal and the need to reduce its green house gases has been increased accordingly. The objective of the study is to examine the status and characterization of mass energy consumption local governmental buildings' green house gas emissions depending on usage (hotel, school, apartment, hospital) through the green house gas emission source unit analysis. The result indicated that the energy source unit was proportional to green house gas source unit and hotel showed the highest green house gas emission source unit per open area of construction unit, followed by hospital, apartment, and then school. In case of apartment, green house gas emission source unit per open area of construction unit decreased as year went on. Meanwhile school building showed a striking increase in the annual energy source unit.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.101-104
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• 2002

This paper propose that is algorithm of power dissipation reduction in the high level synthesis design for DSP(Digital Signal Processor), as the portable terminal system recently demand high power dissipation. This paper obtain effect of power dissipation reduction and switching activity that increase correlation of operands as input data of function unit. The algorithm search loop or repeatedly data to the input operands of function unit. That can be reduce the power dissipation using the new low power high level synthesis algorithm. In this Paper, scheduling operation search same nodes from input DFG(Data Flow Graph) with correlation coefficient of first input node and among nodes. Function units consist a multiplier, an adder and a register. The power estimation method is added switching activity for each bits of nodes. The power estimation have good efficient using proposed algorithm. This paper result obtain more Power reduction of fifty percents after using a new low power algorithm in a function unit as multiplier.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1210-1215
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• 2010

Unit cabin means room, which is installed in the high value-added vessel such as drill ship, offshore platform and FPSO, after pre-assembled. In order to develop the noise control design for a unit cabin, a variety of acoustic tests such as sound absorption, transmission and radiation measurements were carried out by using the deckhouse mock-up. From the tests, it was found out that the sound transmission loss between cabin and corridor was 13 dB below than FPSO standard and the combined noise level of the unit cabin was dominated by the radiated noise from wall panel in low frequency range. Based on the test results, design guidelines for the noise control of the unit cabin were fully established, such as the improvement of sound transmission loss between the cabin and corridor, and radiated cabin noise reduction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1370-1376
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• 2012

This study tried to analyze $CO_2$ emission volume as green-house gases by application of land use patterns and transport policies in District Unit Design. It is postulated a Toy network and various scenarios which are combined land use patterns and transport policies for analyzing $CO_2$ gas reduction. As results, this study shows best District Unit Design technique is the policy that develop mid block and introduction of car free zone to inner 2 way streets. Worst design technique is the policy that make hierarchical network and introduction of access control to outer roads that have been known as a best road policy till nowadays. Therefore, we need more carefully introduce design technique for reduction of $CO_2$ in District Unit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1085-1090
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• 2011

To assure the safety of rolling stock, it is important to perform the fatigue analysis of reduction gear unit in rolling stock considering a variation of velocity and traction motor capability. This paper presents fatigue analysis of the damage of reduction gear unit of railway vehicle under variable amplitude loading(VAL) based on quasi-static fatigue analysis using finite element model and linear Miner's rule. The VAL for the simulation was constructed from the tractive effort curve and train run curves of railway vehicle under commercial operation condition using MSC.ADAMS dynamic analysis. The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the middle gear based on strain-life based approach. The results showed that the frequent high starting torque due to a quick start as well as increasing numbers of stops at station would decrease the fatigue life of reduction gear unit.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3986-3994
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• 2000

A multiple vector reductive processing occurs during the vector inner product operation ([C] = [A] $\bigodot$,$\square$ [B]) and proceeds at the hardware dyadic pipeline unit. Every scalar result has to be generated with the component merging delay time in the multiple vector reduction($\bigodot$). In this paper we propose a new design method by which the component merging time could be eliminated from the multiple reduction and the scalar results from the reduction($\bigodot$) could be generated nearly in the almost same condensed time as the input components are fel>ded in the dyadic pipeline unitlo) or the output components are drained out of the dyadic pipeline unit($\square$), so called a dedicated chained pipeline unit for only a inner product operation.