• Industrial Engineering and Management Systems
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• 제4권1호
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• pp.68-74
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• 2005

Among many dimensional and dimensionless amplitude parameters, kurtosis (4-th normalized moment of probability density function) is generally regarded as a sensitive good parameter for machine diagnosis. However, higher order moment may be supposed to be much more sensitive. Bicoherence is an absolute deterioration factor whose range is 1 to 0. The theoretical value of n-th moment divided by n-th moment calculated by measured data would behave in the same way. We propose a simplified calculation method for an absolute index of n-th moment and name this as simplified absolute index of n-th moment. Some favorable results are obtained.

• 한국소음진동공학회논문집
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• 제11권6호
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• pp.216-222
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• 2001

The paper presents the dynamic stability of a flexible shoe in drum brake systems subjected to a frictional force. The frictional force between the drum and the shoe is assumed as a distributed frictional force, while the shute is modeled as an elastic beam supported by two translational springs at both ends and elastic foundations. Governing equations of motion are derived by energy expressions, and their numerical results are obtained by employing the finite element method. The critical distributed frictional force and the instability regions are demonstrated by changing the stiffness of two translational springs and elastic foundation parameters. It is also shown that the beam loses its stability by flutter and divergence depending on the stiffness of elastic supports and elastic foundation parameters. Time responses of beams corresponding to their instability types are also demonstrated.

• 산업경영시스템학회지
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• 제23권56호
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• pp.9-18
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• 2000

This paper considers the problem of two-machine, M-parallel flow shop scheduling to minimize makespan, and proposes a series of heuristic algorithms and a branch and bound algorithm. Two processing times of each job at two machines on each line are identical on any line. Since each flow-shop line consists of two machines, Johnson's sequence is optimal for each flow-shop line. Heuristic algorithms are developed in this paper by combining a "list scheduling" method and a "local search with global evaluation" method. Numerical experiments show that the proposed heuristics can efficiently give optimal or near-optimal schedules with high accuracy. with high accuracy.

• 한국전통조경학회지
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• 제31권4호
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• pp.22-32
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• 2013

본 연구는 근대 부산에서 발간된 釜山日報와 부산부(釜山府)에서 발간한 <釜山>을 분석하여 근대 부산의 삼대 공원으로 꼽는 고관공원의 성립과정을 밝히고 설계도면을 발굴하여 설계 사상을 분석한 연구다. 고관이라는 장소는 두모포 왜관이 설치되어 있던 곳이다. 부산의 개항과 함께 일본인 거류민의 고토의식을 고양하기 위하여 두모포 왜관의 이전에 진력하다가 급사한 대마도 사신 쓰노에 효고의 묘역과 초혼비를 고관 언덕에 세웠다. 1916년 그 장소를 모금으로 정비한 뒤 부산부(釜山府)에 기부하고, 그곳을 고관공원으로 부르면서 일반에게 공개되었다. 한편, 개항 전 해 부산에 와서 상공업에 종사하면서 거부가 된 오이케 츄스케의 수상기념동상이 부산 개항 50주년을 기념해서 고관공원 부근에 건설한다. 그 동상이 건설된 장소를 부산부에 기부하고, 이를 부산부는 고관공원으로 정비한다. 고관공원의 설계를 의뢰 받은 일본 오사카부 기사 오야 레죠는 고관공원의 설계하기 위하여 부산을 방문하고, 설계도를 부산부에 제출한다. 고관공원의 시설은 신사와 동상, 수목원과 온실, 아동유원 등이었다. 오야의 설계에 나타난 설계 사상은 성과 속의 병치, 산수 컨텍스트의 계승, 공원 컨텐츠의 보완, 국민국가 형성의 도구로 분석되었다. 고관공원은 설계자의 예산에 못 미치는 공사비 2만 원으로 완성한다. 하지만 구체적인 시설 정비에 대해서는 본 연구에서 밝히지 못했다. 1945년 해방 이후 이 장소는 동구청, 주택 등이 들어 서 예전의 흔적을 찾아보기 힘들 정도다. 고관 공원의 소멸 과정을 밝히는 것도 추후의 연구 과제다.

• Journal of Mechanical Science and Technology
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• 제20권1호
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• pp.76-84
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• 2006

Arrayed ultrasonic sensors based on the piezoelectric thin film (lead-zirconate-titanate: Pb($Zr_{0.52}Ti_{0.48})O_{3}$) having composite membrane structure are fabricated. Different thermal and elastic characteristics of each layer generate the residual stress during the high temperature deposition processes, accomplished diaphragm is consequently bowing. We present the membrane deflection effects originated from the residual stress on the resonant frequencies of the sensor chips. The resonant frequencies ($f_r$) measured of each sensor structures are located in the range of $87.6{\sim}111\;kHz$, these are larger $30{\sim}40\;kHz$ than the resultant frequencies of FEM. The primary factors of $f_r$ deviations from the ideal FEM results are the membrane deflections, and the influence of stiffness variations are not so large on that. Membrane deflections have the effect of total thickness increase which sensitively change the $f_r$ to the positive direction. Stress generations of the membrane are also numerically predicted for considering the effect of stiffness variations on the $f_r$.

• Journal of Photoscience
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• 제9권2호
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• pp.350-352
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• 2002

We examined the bacteriochlorophyill/bacteriopheophytin ratios in several species of purple bacteria containing only LHI. The pigment ratios depended greatly on species. Further, Rhodospirillum rubrum showed wide variation when grown under different light intensity, and Rhodobium marinum showed significant variation from culture to culture even under the same light conditions. The protein ratios of a/RC and $\beta$/RC estimated by SDS-PAGE of chromatophores of Rsp. rubrum and Rbi. marinum exhibited the ratio of $\beta$/$\alpha$ > 1. These findings gave us the novel idea that there are two types of LHl; one is a C-shaped open antenna composed by $\alpha$$\beta$ units surrounding a RC, and another is a small closed ring antenna composed by $\alpha$$\beta$ units located peripherally in a variable ratio to the core complex like LH2.

• Corrosion Science and Technology
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• 제7권2호
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• pp.99-111
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• 2008

Copper was exposed unsheltered and sheltered in four humid tropical sites, representing urban, urban-industrial, urban-marine and rural environments. The corrosion rates and the sequence of corrosion product formation are presented and discussed in relation with climatic and atmospheric pollution parameters. Chemical compositions of corrosion products were found to depend on environments and duration of exposure. In all environments, cuprite was the predominating corrosion product that formed first and continuously increased during the exposure. Among the sulphur-containing corrosion products, posnjakite and brochantite were more frequently found and the first formed earlier. Nantokite was the most common chlorine-containing products for most cases, except the high-chloride environment, where atacamite was detected instead. The corrosion rate of copper was well indicated by the colour of patina. The red-purple colour corresponded to the high corrosion rate and the greenish grey colour corresponded to the low corrosion rate. Corrosion rate of sheltered copper in urban-marine environment increased with the exposure time.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.1-5
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• 2003

This paper deals with dynamic instability of slender rocket-propelled flying bodies, such as launch vehicle and advances missiles subjected to aerodynamic loads and an end rocket thrust. A flying body is simplified into a uniform free-free beam subjected to an end follower thrust. Two types of aerodynamic loads are assumed in the stability analysis. Firstly, it is assumed that two concentrated aerodynamic loads act on the flying body at its nose and tail. Secondly, to take account of effect of unsteady flow due to motion of a flexible flying body, aerodynamic load is estimated by the slender body approximation. Extended Hamilton's principle is applied to the considered beam for deriving the equation of motion. Application of FEM yields standardeigen-value problem. Dynamic stability of the beam is determined by the sign of the real part of the complex eigen-values. If aerodynamic loads are concentrated loads that act on the flying body at its nose and tail, the flutter thrust decreases by about 10% in comparison with the flutter thrust of free-free beam subjected only to an end follower thrust. If aerodynamic loads are distributed along the longitudinal axis of the flying body, the flutter thrust decreases by about 70% in comparison with the flutter thrust of free-free beam under an end follower thrust. It is found that the flutter thrust is reduced considerably if the aerodynamic loads are taken into account in addition to an end rocket thrust in the stability analysis of slender rocket-propelled flying bodies.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제16회 학술발표회 논문초록집
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• pp.91-94
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• 2001

A structural test of the wind turbine rotor blade must be required to evaluate the uncertainty in design assessment due to use of material, design concepts, production processes and so on, and the possible impact on the structural integrity. In the full-scale static strength test, the measuring parameters are strain, displacements, loads, weight and the center of gravity. There are test equipments, measuring sensors, a test rig and fixtures to obtain measuring parameters. In order to simulate the aerodynamics load, the three-point loading method instead of the one-point loading method is applied. There is slightly some difference between the measured results and the predicted results with the reference fiber volume fraction of 60%. However, the agreement between the measured results and the predicted results with the actual fiber volume fraction of 52.5% is good. Even though a slightly non-linearity from 80% loading to 100% loading, a linear static solution is sufficient for the design purpose as the amount of the non-linearity is relatively small. Comparison between measured and predicted strain results at the maximum thickness positions of the blade profile for 0.236R(5.56m), 0.493R(11.59m) and 0.574R(13.43m), under 20%, 40%, 60%, 80% and 100% loadings for the upper part of the blade. The predicted values are in good agreement with the measured values.

• 농촌계획
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• 제23권1호
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• pp.165-174
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• 2017

Four requirements for the operating and supporting system for sustainable landscape management will be discussed through this paper. The requirements are based on multiple case studies on the structure and the process of development of three organizations that have been contributing to the sustainable rural landscape management in Japan since 1989. The first requirement is that the residents should recognize regional problems and voluntarily organize a group which can properly deal with the problems. Secondly, members of the organization should have a solid grasp of the goal of their activities (or founding principal of the organization) and share it among themselves. Founding principal should include the history of natural circulation system in the area, cultural features and a future plan in association with human resources. Thirdly, the administration of the organization should be separated from the founder, the residents. The administration, such as business promotion, becomes more effective when consigned to a separate entity, not to the residents. Lastly, the interaction among separate entities is crucial to promote diverse activities for the local landscape management. The administrators and experts need to cooperate to draw a precise conclusion regarding the way of interaction. These requirements drawn from the Japanese case studies should be localized to the Korean circumstances for further adoption.