• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.160-165
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• 2004

At this research, we examined probability of light bulb's life span value and prediction on purpose to inquire out the span of repeat velocity as fracture probability by executing the fatigue test, which is considered property of Tungsten filament's thermal fatigue used as an automobile bulb. As a result we can confirm what the most suitable solution is weibull distribution and log normal distribution. Tungsten filament's span gets longer as the fatigue repeat velocity gets shorter And, repeat span is about 15%~40% shorter than sequence life span.

• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.17-22
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• 2002

Availability is an important characteristic of a repairable component. Iyer(1992) obtained the 'limiting efficiency'(not the `steady state availability') of the age-dependent minimal repair model which was first considered by Block et al.(1985). However the existence of the steady state availability of the model has not been reported. In this note, the existence of the steady state availability of the model is shown and a brief remark on the importance of the property is given.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1901-1903
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• 1996

In This paper, to understand statistical properties of breakdown voltage, the experiment is performed on four gaps of different electrode area, ranging from $17.44[cm^2]$ to $1809.5[cm^2]$, in $SF_6$ gas. Statictcial property of breakdown is confirmed Weibull distribution and as area of electrode is increased, breakdown voltage is decreased and converged constant value $E_0$.

• Korean Security Journal
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• no.3
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• pp.231-250
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• 2000

The police exsist to prevent and to suppress a crime, to protect the life and property of a nation, to keep order and to offer service to a nation. The purpose of this study is to examine the factors influencing police recruitment with social and scientific techniques. This study uses statistical technique that analyzes questionaire of police cadet.

• International Journal of Highway Engineering
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• v.19 no.4
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• pp.27-36
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• 2017

PURPOSES : The purpose of this study is to perform a reliability analysis of the proposed wind load combination which governs the design of support structures of subsidiary road facilities, and to evaluate whether the target reliability of the design is satisfied. METHODS : The statistical estimation method is applied and the design period of the support structure is used to obtain the statistical property of the wind load. In addition, the statistical properties of the strength of support structures are obtained from a literature review and simulation study. Actual support structures are designed by the proposed load combination and are used as the examples to examine if the target reliability is obtained. RESULTS : The result of the reliability analysis performed by using the statistical properties of load and resistance for the support structure in this study indicates that the proposed wind load combination satisfied the target reliability index of the design. Also, the convenience of the design is achieved by adopting the same design wind velocity given in the bridge design code by applying the wind velocity ratio defined for the design period of the support structure. CONCLUSIONS : It is presented that the design using the wind load combination proposed in this study achieved the target reliability index and the design wind load for different design periods can be conveniently defined by applying the velocity ratio proposed in this study.

• Culinary science and hospitality research
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• v.14 no.2
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• pp.61-72
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• 2008

The purpose of this study was to analyze the difference in preference and property of native local foods among students living in Busan. It concentrated on the students who were majored in food service in five universities in Busan. From September 1st to 30th, 2007, 300 copies of questionnaire were distributed and 260 returned were included in the statistics. The statistics was conducted by frequency analysis, T-test(average deviation verification), technical analysis and one way ANOVA for an accurate result of the study. As a result, it was found that Gayamilmyeon(M=4.42) showed the most preference for 25 native local foods of Busan(sansungmakgeoli, dongraepajeon, steamed carp, catfish soup, corbicula soup, roasted eel, gijang raw hairtail, dongrae mugwort cake, sansung roasted goat, gijangkkomjangeo, steamed frogfish, duck dish, guponoodles, gayamilmyeon, sliced raw fish, molsim hot-pepper fish stew, hairtail stew, anchovy stew, miyeoksulchi, gompi salted dish, salted raw anchovy dish, roasted kkomjaneo, salted sliced persimmon dish, salted bean leave dish, kkasiri soup). On the other hand, it was found that Miyeoksulchi(M=2.66) showed the least preference among them. As a result of the analysis of the difference in demographic characteristics and property of native local foods, it was presented that there was no difference in the statistical analysis by sex but significant difference in taste, quantity, service, price, freshness, sanitation, packing condition and originality, etc by age, department, academic year, type of residence, family member, living period in Busan and monthly spending. It was considered to conduct a more in-depth study to promote native local foods and interest in the food of Busan in university students.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.846-853
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• 2006

In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam with this input parameter. The rockfill material properties for parametric study were obtained from the results of large scale triaxial tests on 34 rockfill materials in the 22 different sites. From the statistical analysis on these data, some statistical characteristics of rockfill material properties such as property range, distribution characteristics, and correlation between the properties were investigated. based on these characteristics, 27 property combinations were constituted by Latin Hypercube sampling method. Dam crest displacements after construction, impounding, and earthquake loading were evaluated by static and dynamic numerical analysis on each combination. From the sensitivity analysis, it was found that the crest displacement of CFR type dam was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the settlement and horizontal displacement of dam crest logarithmically decreased as the shear modulus increased and the difference between the maximum value and the minimum vale amounted to about 9.5 times in case of settlement and about 10 times in case of horizontal displacement.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.5
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• pp.701-709
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• 2010

This paper presents an efficient signature recognition method by using the hybrid similarity criterion, which is in inverse proportion to distance and in proportion to correlation between the images. The distance is applied to express the spacial property of image, and the correlation is also applied to express the statistical property. The proposed criterion provides the robust recognition to both the geometrical variations such as position, size, and rotation and the shape variation. The normalized cross-correlation(NCC), which is calculated by considering 4 directions based on the histogram of binary image, is applied to express rapidly and accurately the similarity between the images. The proposed method has been applied to the problem for recognizing the 20 truck images of 288*288 pixels and the 105(3 persons * 35 images) signature images of 256*256 pixels, respectively. The experimental results show that the proposed method has a superior recognition performance that appears the image characters well. Especially, the hybrid criterion of NCC and ordinal distance has a superior recognition performance to the hybrid criterion using city-block or Euclidean distance.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.1-12
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• 2017

Many stochastic processes satisfy the Markov property exactly or at least approximately. An interested property in the Markov process is the first passage time. Since the sequential analysis by Wald, the approximation of the first passage time has been studied extensively. The Statistical computing technique due to the development of high-speed computers made it possible to calculate the values of the properties close to the true ones. This article introduces an exponentially weighted moving average (EWMA) control chart as an example of the Markov process, and studied how to calculate the average run length with problematic issues that should be cautioned for correct calculation. The results derived for approximation of the first passage time in this research can be applied to any of the Markov processes. Especially the approximation of the continuous time Markov process to the discrete time Markov chain is useful for the studies of the properties of the stochastic process and makes computational approaches easy.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.91-97
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• 2009

Hazardous material (HazMat) is the material or substance that poses an unreasonable risk to human safety and health, and to property when transported in gases, solids, and liquids of all sizes. When HazMats are improperly released, they have potential to harm humans, property, or the environment to be considered hazardous, resulting in human-caused disasters. As the Korean economy has advanced, the use of HazMats has increased. And, the total number and the impacts of HazMat incidents have grown up. It increases the risk of HazMat incidents. When many goods of HazMats are transported from supply points to demand places, it is important to know what the types and characteristics of HazMat incidents are in terms of disaster management. The objectives of this research are: (1) to investigate types and characteristics of HazMats that generate HazMat incidents in Korea, and (2) to analyze time-series trends of HazMat incidents in terms of facilities and/or transportation. Statistical analysis methods including frequency analysis or analysis of category data are applied to examine the significance of difference in HazMat incidents.