• 한국안전학회지
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• 제6권3호
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• pp.21-26
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• 1991

In this study, a crack closure behavior of Al-alloy 5052-H38 was investigated. The fatigue test was performed by the four-point bending test under the contast amplitude load. Stress ratio R was changed from-1.0 to 0.5. To mcasure the fatigue crack opening point, the graph of load vs. subtracted displacement by computer program was obtained from the X - Y plotter. In order to gain the displacement data, a strain gage was attached at the back surface against the notched side. Uslng the conception of crack closure and influence of on crack growth rate a model for crack growth rate is developed for Al-alloy 5052-H38.

• 경영과학
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• 제28권1호
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• pp.53-60
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• 2011

Time series analysis methods have been traditionally used in stock price prediction. However, most of the existing methods represent some methodological limitations in reflecting influence from external factors that affect the fluctuation of stock prices, such as oil prices, exchange rates, money interest rates, and the stock price indexes of other countries. To overcome the limitations, we propose a network based method incorporating the relations between the individual company stock prices and the external factors by using a graph-based semi-supervised learning algorithm. For verifying the significance of the proposed method, it was applied to the prediction problems of company stock prices listed in the KOSPI from January 2007 to August 2008.

• 한국통신학회논문지
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• 제21권5호
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• pp.1230-1239
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• 1996

This paper analyzes matched-filter acquistion performance of a direct-sequence spread-specturm multiple-access system in a Rayleigh fading channel. For an application of multiple access system, multiple access interference is considered in the performance analysis. A signal flow graph technique is used to derive mean acquisition time in terms of detection and false alarm probabilities. As aresult of performance analysis, it is shown that mean acquisition time increases as fading rate becomes faster andthe numbre of users increases, and it decreases as a matched-filter length becomes logner. The variation of parameter values hs much influence on acquisition performance as SNR/chip becomes smaller.

• 한국분무공학회지
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• 제11권2호
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• pp.105-112
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• 2006

A unique feature of fluidic atomizers is that the nozzle geometry produces a thin capillary Jet which is forced to oscillate on a 2-dimensional plane through the use of a passive feedback mechanism. The objective of the current work is to characterize the influence of the stagnation pressure at the nozzle exit, jet oscillation and stretching on the breakup properties of the capillary ligament. To achieve this, shadow graph technique is used to measure size, shape, velocity and the number density of the droplets as a function of the position within the spray fan. The breakup length, defined as the radial distance from the breakup point, is analyzed as a function of the non-dimensional parameters. Finally, a kinematic model is developed to simulate the breakup of the oscillating jets at low stagnation pressures. Using the existing jet breakup theories, the model is used to predict the size and diameter distribution of the droplets after primary atomization.

• 대한기계학회논문집
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• 제8권3호
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• pp.210-216
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• 1984

본 연구에서는 이러한 화염의 구조를 자세히 파악하기 위하여, 화염의 온도분 포 및 가스농도분포 등을 비교적 정밀하게 측정하고 Shadow graph 등을 통하여, 선회 화염의 거시적인 구조적 특성을 알아보고 일산화질소, 탄화수소 및 일산화탄소 등의 생성특성을 규명함으로서 실제 버어너에서의 기하학적 변형에 따른 화염구조의 예측과 수치해석을 위한 기본 데이타를 얻고, 공해물질발생과 화염구조와의 상관관계를 제시 하는데 그 목적이 있다.

• Communications for Statistical Applications and Methods
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• 제7권3호
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• pp.741-757
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• 2000

In may experimental situations, whenever a block design is used, the block effect is usually considered to be fixed. There are, however, experimental situations in which it should be treated as random. The choice of a blocking arrangement for a response surface design can have a considerable effect on estimating the mean response and on the size of he prediction variance even if the experimental runs re the same. Therefore, care should be exercised in the selection of blocks. In this paper, in the presence of a random block effect, we propose a graphical method or evaluating the effect of blocking in response surface designs using cuboidal regions. This graphical method can be used to investigate how the blocking has influence on the prediction variance throughout all experimental regions of interest when this region is cuboidal, and compare the block effects in the cases of the orthogonal and non-orthogonal block designs, respectively.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1052-1057
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• 2010

Dynamic stability of rotating blade considering gravity effect is investigated in this paper. Equations of motion for the beam is derived by employing hybrid deformation variable method and transformed into dimensionless form. The present modeling method is verified by RecurDyn. Stability diagrams are presented to show the influence of the configuration of the beam and angular velocity on the dynamic stability by applying Floquet's theory. Since the natural frequencies are varied when the blade has rotating motion, it is found that relatively large unstable regions exist approximately 1.1 times as high as the first bending natural frequency and half of the sum of first and second bending natural frequency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.557-560
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• 1988

In this paper, we present a new k-way partitioning algorithm for a graph of an electrical circuit wherein nodes and edges are regarded as cells (modules) and nets, respectively. In contrast to the previous work, our method is based upon a linearly ordered partition paradigm. We also claim that the maximum number of netcuts mostly governs the performance of k-way partitioning, thus having influence on the construction of a new cost function. In addition, our approach elaborates upon balancing the partition size. Our experiments show excellent results in comparison with previous k-way partitioning algorithms.

• 한국국방경영분석학회지
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• 제14권1호
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• pp.42-52
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• 1988

Many programmers start debugging by reading the faulty program from start to bottom without investigating carefully the erroneous program. Expert programmers, however, trace backward from a particular variable in a specific statement to identify all possible sources of influence on the value of variable (program slice). Weiser proposed a slicing algorithm (method) that is complex, iterative and still in modification [3,4]. This paper presents a method to generate a program slice by use of matrix computation which represents all possible slices of the program. The matrix representation of a program is soundly based on the graph theory of data dependency.

• 설비공학논문집
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• 제10권5호
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• pp.523-534
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• 1998

The convection heat transfer on horizontal circular tube is studied as a conjugated heat transfer problem. With uniform heat generation in a cylindrical heater placed in a cross flow boundary condition, heat flow that is conducted along the wall of the heater creates a non-isothermal surface temperature and non-uniform heat flux distribution. In the present investigation, the effects of circumferential wall heat conduction on convection heat transfer are investigated for the case of forced convection around horizontal circular tube in cross flow of air and water. Non-dimensional conjugation parameter $ K^*$ which can be deduced from the governing energy differential equation should be used to express the effect of circumferential wall heat conduction. Two-dimensional temperature distribution$ T({\gamma,\theta})$ is presented. The influence of circumferential wall heat conduction is demonstrated on graph of local Nusselt number.