• Journal of Information Technology Applications and Management
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• 제24권2호
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• pp.71-80
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• 2017

Software reliability is one of the most elementary and important problems in software development In order to find the software failure occurrence, the instantaneous failure rate function in the Poisson process can have a constant, incremental or decreasing tendency independently of the failure time. In this study, we compared the reliability performance of the software reliability model using the parameters of Pareto life distribution with the intensity decreasing pattern and the shape parameter of Erlang life distribution with the intensity increasing and decreasing pattern in the software product testing. In order to identify the software failure environment, the parametric estimation was applied to the maximum likelihood estimation method. Therefore, in this paper, we compare and evaluate software reliability by applying software failure time data. The reliability of the Erlang and Pareto life models is shown to be higher than that of the Pareto lifetime distribution model when the shape parameter is higher and the Erlang model is more reliable when the shape parameter is higher. Through this study, the software design department will be able to help the software design by applying various life distribution and shape parameters, and providing basic knowledge using software failure analysis.

• 한국군사과학기술학회지
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• 제19권3호
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• pp.311-318
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• 2016

This paper shows storage life estimation of next IR(infrared) flare material through accelerated degradation tests. Three temperature conditions for the accelerated degradation tests are 55, 65 and $75^{\circ}C$. Six performances of IR flare material are burning time, IR peak/continuous Intensity, total energy of near/mid-IR and color ratio, and they were measured after the tests. Storage life of the IR flare material was estimated through both analyzing the degradation data of those performances and applying distribution-based degradation models to the data. Over 30 years of storage life at $20^{\circ}C$ is estimated in terms of IR peak intensity with reliability 0.99 and confidence level 99 %. Additionally, 10 years of storage period at $21^{\circ}C$ would be equivalent to 68 days of accelerated test at $65^{\circ}C$ from the activation energy in Arrhenius model.

• 대한원격탐사학회지
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• 제18권5호
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• pp.255-261
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• 2002

Strong and coherent radar backscattering signals are observed over oyster sea farms that consist of artificial structures installed on the bottom. We successfully obtained 21 coherent interferograms from 11 JERS-1 SAR data sets even though orbital baselines (up to 2 km) or temporal baselines (up to 1 year) were relatively large. The coherent phases preserved in the sea farms are probably formed by double bouncing from sea surface and the sea farming structures, and consequently they are correlated with tide height (or instantaneous sea level). Phase unwrapping is required to restore the absolute sea level. We show that radar backscattering intensity is roughly correlated with the sea surface height, and utilize the fact to determine the wrapping counts. While the SAR image intensity gives a rough range of absolute sea level, the interferometric phases provide the detailed relative height variations within a limit of $2{\pi}$ (or 15.3 cm) with respect to the sea level at the moment of the master data acquisition. A combined estimation results in an instantaneous sea level. The radar measurements were verified using tide gauge records, and the results yielded a correlation coefficient of 0.96 with an r.m.s. error of 6.0 cm. The results demonstrate that radar interferometry is a promising approach to sea level measurement in the near coastal regions.

• 수산경영론집
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• 제51권4호
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• pp.1-18
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• 2020

The paper aims to explore existence and degree of remaining fisheries damages after the completion of undertaking the Four Major Rivers Project focusing on the case of Yeongsan river. The paper seeks to show the necessity of consideration of periods of fishery resources recovery in the estimation of ex-post fisheries damages of the project by inferring the analysis of the annual variation of environmental indicators in the river. Therefore, the paper suggests three years of remaining periods of fisheries damages of the project utilizing the variation trend of ex-ante and ex-post annual output data of inland fisheries in Jeonnam province and individual catch of fisheries. In the measurement of the annual degree of fisheries damages during periods of fishery resources recovery, the paper attempts to suggest the method of comparision of day catch data per vessel between ex-ante and ex-post periods of the project, which were investigated by the same institute. Here the paper tries to make correction of ex-post catch data for holding the same catching condition as ex-ante situation by adopting the concept of competitive intensity of catching which was derived from the decreasing rate of number of fishing households in the area of Yeongsan river.

• 한국소음진동공학회논문집
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• 제23권4호
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• pp.315-323
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• 2013

Tire noise is divided into a road noise(structure-borne noise) and a pattern noise(air-borne noise). Whilst the road noise is caused by the structural vibration of the components on the transfer path from tire to car body, the pattern noise is generated by the air-pumping between tire and road. In this paper, a practical method to estimate the pattern noise inside a passenger car is proposed. The method is developed based on the sound intensity and airborne source quantification. Sound intensity is used for identifying the noise sources of tire. Airborne source quantification is used for estimating the sound pressure level generated by each noise source of a tire. In order to apply the airborne source quantification to the estimation of the sound pressure, the volume velocity of each source should be obtained. It is obtained by using metrics inverse method. The proposed method is successfully applied to the evaluation of the interior noises generated by four types of tires with different pattern each other.

• 전기학회논문지
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• 제62권9호
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• pp.1290-1296
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• 2013

The light intensity which represents the relative amount of brightness and darkness is very important feature to discern the color hue and its relevant information. With this aim, we devise a new optical system and method to analyze the light intensity. Our suggested system including a phototransistor and white-high-brightness chip light-emitting diode intend estimate the contrast value utilizing Image Research Institute(I.R.I.) Hue & Tone samples which includes 120 color sheets arranged by the color hue and tone. As a result, we confirmed that the brightness of the color checker can be accurately estimated by a high-brightness light-emitting-diode optical system.

• 대한산업공학회지
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• 제36권1호
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• pp.69-77
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• 2010

The failure rate model of External Environment Maintenance(EEM) for a system under severe environment is investigated. EEM, which is recently introduced concept, is a maintenance activity controlling external environment factors that potentially cause system failure such as cleaning equipment, controlling temperature (humidity) and removing dust inside of electronic appliances. EEM can not have any influence on the inherent failure rate of a system but reduce the severity of the external environment causing failure since it deals with only external environment factors. Therefore, we propose two failure rate models to express the improvement effect of EEM: The intensity reduction model and age reduction model. The intensity and age reduction models of EEM are developed assuming the quality of improvement effect is proportioned to an extra intensity or age respectively. The validation of proposed failure rate models is performed in order of data generation, parameter estimation and test for goodness-of-fit.

• 대한한의학원전학회지
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• 제21권2호
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• pp.49-57
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• 2008

Objective : To overcome the limit which is unaware of the herbal effects intensity of Traditional study based on "Yakdaeron(藥對論)", classification methods based on the curative effects, we aimed to express the herbal formula's effects numerically, compare one herbal formula with other herbal formulas and calculate the herbal effects and the herbal effects intensity by using conception, weight of the herbal effects. Method : We calculated the herbal effects through the proportion of each herbal quantity to whole quantity of the herbal formula and weight of the herbal effects through frequency and quantity in use on specific herbal effects field and the other herbal effects fields. We applied the weight of the herbal effects to calculating the herbal effects through the proportion of each herbal quantity to whole quantity of the herbal formula. Results : We expressed the herbal formula's effects numerically. By giving weight to the herbal effects, we found that 3-4 major effects among 4-5 major effects are ranked in 5th.

• 한국수자원학회논문집
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• 제32권3호
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• pp.247-254
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• 1999

우리 나라 주요 우량관측소 22개 지점의 매년 최대치 강우자료에 대하여 빈도해석을 실시하였다. 매개변수 추정방법은 모멘트법, 확률가중 모멘트법, 최우도법 등이며, 매개변수 적합성, 도시적 해석, 분리효과, 적합도 검정결과 GEV 분포가 우리 나라 강우자료에 대하여 가장 적합한 확률분포형으로 나타났다. 선정된 GEV 분포형을 모집단의 확률분포형으로 가정하여 재현기간별 확률강우량을 산정하므로써 지역적 해석을 실시하였으며, 정확도 있는 선형화 기법을 통해 회귀분석을 실시하여 확률강두강도식을 유도하였다. 본 연구에서 유도된 확률강우강도식은 실무차원에서 임의 지속기간의 재현기간별 확률강우량을 간편하게 구할 수 있을 것으로 판단된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.77-87
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• 1997

The earthquake data(M$\geq$4.0) for post-1900 in the Korean Peninsula show temporal variation with active and quiet periods. The pattern is quite similar to northeastern China and Inner Zone of Southwest Japan. Yeongweol earthquake occurred in the seismic gap region of the Korean Peninsula. This is the first medium-size earthquake in inland region of the southern peninsula since 1978. The intensity based on the felt area estimation of about 400 places shows MMI III-Ⅷ in inland region. IIon Cheju Island and Ion Ulreung Island. The isoseismal of MMI Ⅶ shows an elongated circle in the direction of NE-SW and covers some parts of Jungdong-myon, Yeongweol-kun, Sindong-eup and Nam-myun, Jeongseon-kun. There occurred quite strong shaking, numerous cracks on the walls of buildings, falling and movement of slate and tiles on the roofs, falling of tiles from the wall and falling of materials from desks, rook falling from mountain and collapse of gravel lauers on the river side. The least square fitting of the intensity data of the Yeongweol earthquake by a popular intensity attenuation relation yields the following : I=Io＋1.82249 - 0.65295*InR - 0.00707*R