• 한국정밀공학회지
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• 제29권3호
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• pp.319-323
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• 2012

Transmission is one of the important pars to transmit power from engine to wheels. Mass reduction gears can make the engine power requirement reduce, and can make dynamic performance and fuel efficiency of vehicle improve. Transmission gears are modified for mass reduction without changing their tooth shapes, face widths, and modules by using shape optimization and re-check process. Also structural stability is verified by FEA.

• 무역상무연구
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• 제74권
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• pp.1-23
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• 2017

The buyer must examine the goods, or cause them to be examined, within as short a period as is practicable in the circumstances. Article 38 lays down a fundamental principle that requires the buyer to examine quickly the goods delivered by the seller. Article 38 (1) provides that the examination be made within as short a period as practicable in the circumstances. The goods have to be examined within as short a period as is practicable in the circumstances. The rule is based on the fundamental idea of reasonableness, meaning that the buyer must examine the goods as soon as reasonably possible. It may be said that the buyer should act reasonably fast. Article 38 (2), (3) concerns sales involving carriage of the goods, where the seller's obligation to deliver consists in handing the goods over to the first carrier for transmission to the buyer. In this case the buyer is generally able to examine the goods only after they have come to destination. Article 38 (3) takes into account the case where the buyer redirects the goods in transit or re-dispatches them to another destination. Redirection in transit occurs when the destination is changed before the goods are received by the buyer. The buyer could re-dispatch the goods without having them unloaded, or re-dispatch them through another carrier.

• 한국결정성장학회지
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• 제26권1호
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• pp.1-7
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• 2016

RE : YAG 단결정은 레이저 발진 소재로 다양한 성장 변수를 제어하면서 Czochralski법으로 성장된다. 성장과정 동안 고액계면의 온도구배 및 회전속도에 의해 발생하는 결함들은 결정의 광학적 특성 저하로 작용하기 때문에 결함 분석을 통한 결정 품질의 향상을 필요로 한다. 격자결함 밀도 분석(EPD)을 통하여 성장된 RE : YAG 단결정의 표면 결함 존재를 확인하였고, 이를 통해 투과전자현미경(TEM) 분석영역을 선택하였다. 선택한 영역의 시편은 트라이포드 연마 방법으로 제작하였고, 200 kV 투과전자현미경과 300 kV 전계 방사형 투과전자현미경(FE-TEM)을 사용하여 buckling, rod shaped, 내부응력에 의한 bend contours, 편석 등의 결함들을 관찰하였다.

• 대한전자공학회논문지TC
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• 제41권6호
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• pp.49-58
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• 2004

애드 혹 네트워크에서 수명을 연장하기 위한 방법 중 하나인 경로 재설정 기법은 일정 노드로 라우팅 기능 부담의 편중을 막기 위해 일정량의 에너지 사용 후. 새로운 경로를 다시 찾는다. 경로 재설정 기법은, 라우팅 기능 분담에 의한 네트워크 수명연장 측면에서 뛰어난 성능을 보인다. 그러나 경로 재설정은 플러딩(Flooding)에 의한 경로 탐색 과정이 포함되기 때문에 그 시그널링 오버헤드는 상당하다 경로 재설정 기법은 라우팅 기능의 분담으로 각 노드의 수명 연장을 기대할 수 있으나, 잦은 경로 재설정이 발생할 경우 시그널링 오버헤드로 인해 그 성능 향상이 반감될 수 있다. 본 논문에서 제안하는 경로 선택 알고리즘(Enhanced Route Selection Algorithm, ERSA)은 패킷 전송 비용과 함께 시그널링 오버헤드의 정도를 나타내는 경로 재설정 비용을 계산하여 경로 선택 과정에 활용한다. ERSA는 경로의 재설성 과정에서 발생하는 시그널링 오버헤드를 줄이는 새로운 알고리즘으로, 경로 재설정 비용을 경로 선택 과정에서 고려하여 재설정 과정 발생 횟수를 줄임으로써 네트워크의 에너지사용을 효율적으로 수행할 수 있다. 시뮬레이션을 통해 성능을 비교한 결과, ERSA는 타 알고리즘보다 네트워크를 구성하는 모든 노드의 에너지 총합을 나타내는 네트워크 에너지, 경로 재설정 시그널링에 의한 에너지 소모량, 세션이 지속되었을 때의 네트워크 에너지 감소성향 등의 측면에서 뛰어난 성능을 보인다.

• 한국기계가공학회지
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• 제16권3호
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• pp.54-62
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• 2017

When gears mesh, shock and noise are produced as results of tooth error and tooth deformation under load. Transmission error (TE) is the most important cause of gear noise and vibration because TEs affect the changes of the force and the speed of gears. Gear tooth modification research plays a positive role in reducing TE and improving the design level and transmission performance of transmission systems. In high-precision manufacturing gear, gear tooth modification is also commonly used to reduce noise in practical applications. In order to study the accuracy of gear transmission, some empirical gear profile micro-modifications are introduced, and a helical gear pair is modeled and analyzed in RomaxDesigner software to investigate the utility of these modification methods. Some of these will be selected as experimental proposals for gear pairs, and these manufactured gears will be tested and compared in a semi-anechoic room later. The final purpose of this study is to find reasonable and convenient empirical formulae to facilitate improved gear production.

• 한국기계가공학회지
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• 제13권5호
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• pp.21-27
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• 2014

Currently, wind power has become a major research field in the area of sustainable development. As one important component of a wind turbine transmission system, most instances of downtime due to a gearbox failure are caused by bearing failures. Gearboxes for wind turbines must have the highest levels of reliability over a period of approximately 20 years, withstanding high dynamic loads. At the same time, a lightweight design and cost minimization efforts are required. These demands can only be met with a well-thought-out design, high-quality materials, a high production quality and proper maintenance. In order to design a reliable and lightweight gearbox, it is necessary to analyze methods pertaining to the bearing rating lifetimes of the standard and of different companies, also including calculation methods for modification factors. This can determine the influence of the bearing lifetime.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.2065-2069
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• 2004

This paper presents an adaptive equalizer using finite impulse response (FIR) filter and least-mean square (LMS) algorithm. Herein, the variable step-size technique (VSLMS) for compensating the amplitude of chrominance signal is utilized. The proposed equalizer can be enhanced and compressed the chrominance signal at color subcarrier. The LMS algorithm employed in simplicity structure but gives slow convergence speed. Thus, the variable step-size is very attractive algorithm due to its computational efficiencies and the speed of convergence is improved. In addition, experimental results are carried out by using the modulated 20T sine squared test signal. It is shown here that the adaptive equalizer can be equalized the amplitude chrominance distortion in color television transmission without relative delay distortion.

• 한국기계가공학회지
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• 제16권5호
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• pp.1-6
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• 2017

Gear tooth micro-geometry modifications include the intentional removal of material from the gear teeth flanks, so that the shape is no longer a perfect involute. If the gear shapes are perfect, then the gear tooth meshing is better, therefore the gears will transmit input torque in a more efficient manner without the generation of high frequency engine fluctuation noise. In this paper, we study tooth micro-geometry optimization of rear gear set in 2 speed planetary gear reducers. Analysis revealed problems which are need of modification. Based on the results, tooth micro-geometry was used to deal with load distributions on the rear gear set.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2007년도 추계학술발표대회 논문집
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• pp.149-154
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• 2007

The city hotel of today lodges and, from eating and drinking putting first cultural exchange, information transmission and sports and the leisure back to be various the open community of the city which equips a composition facility as the market fixation it is being turning out. Like this regional and culture flow scope of the user fall in love, width widely try to be diffused the data about the internal organs re-analysis our country hotel plan the place where it is the actual condition where the system and diverse royal tomb city hotel plan is coming to be demanded regarding very is the actual condition which is insufficient. The research which it sees hereupon from domestic is erected in existing and the city hotel which is coming to be operated re- internal organs in the object it investigate, analyze re- internal organs and new city hotel plan hour to present a plan fundamental data and the guide regarding the internal organs re-quality of the crew-serve space interior construction it could be applied there is an objective of the research by the box sleep.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권5호
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• pp.238-242
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• 2001

In this paper, we extracted design parameters for re-entrant mode microstrip directional coupler using FE(finite element) calculations. The microstrip directional coupler suffers from a poor directivity due to effect of the inhomogeneous dielectric including both dielectric substrate and air in microstrip transmission lines. Thus, the phase velocity of even mode is not equal to that of odd mode. In order to improve the directivity of microstrip directional coupler, a novel re-entrant mode microstrip directional coupler was employed. In microstrip configuration, the high directivity can be reached by matching the even- and odd-mode effective phase velocities. Through the values of capacitance obtained from 2-dimensional FE calculations, the phase velocities for each mode and the design parameter were extracted for the proposed parallel coupled-line configuration. Based on the extracted design parameter with phase matching condition, we designed and fabricated a 30dB directional coupler at 0.85GHz. Experimental results show good performance with excellent, isolation and directivity.