• 제목/요약/키워드: mean past life function

검색결과 10건 처리시간 0.023초

Some Characterization Results Based on Dynamic Survival and Failure Entropies

  • Abbasnejad, Maliheh
    • Communications for Statistical Applications and Methods
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    • 제18권6호
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    • pp.787-798
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    • 2011
  • In this paper, we develop some characterization results in terms of survival entropy of the first order statistic. In addition, we generalize the cumulative entropy recently proposed by Di Crescenzo and Logobardi (2009) to a new measure of information (called the failure entropy) and study some properties of it and its dynamic version. Furthermore, power distribution is characterized based on dynamic failure entropy.

Why Genuine Luxury Brands Are Consumed? Counterfeits? Examining Consumer Identification

  • Suh, Hyunsuk
    • Asia Marketing Journal
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    • 제14권3호
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    • pp.69-102
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    • 2012
  • Owing to increased number of luxury brand users, both genuine and counterfeit luxury product consumption continues to increase every year. Luxury brand is defined as use or display of a particular branded products which brings the ownership prestige apart from its functional utility(Grossmand and Shapiro 1988). Some luxury brands have imitations sold in marketplace due to their popularity. These imitations or counterfeits have been jumping on the bandwagon of the upturn in sales of their originals. The purpose of our study is to understand consumer's underlying motives to consume luxury brands, genuine and or counterfeits. To do this, we propose functional theories of attitudes, decision-making styles, and life attitudes to form the determining causes for different consumption choices of luxury brands: genuine brands, counterfeit brands, both genuine and counterfeit brands, and no consumption on luxury brands types. In proposed causal pathways, we examine moderated effects of socio-psychological factors to further investigate if consumer profiles would exert influences in causal relationships. From the existing theories of functional attitudes: value-expressive and social-adjustive attitudes, we developed and introduced a new measure of rationality-consumptive attitude. From the existing eight decision-making characteristics of consumer styles inventory(CSI), three measures of high-quality, hedonic-shopping, and price-shopping styles were primarily applied in the study along with newly introduced measure of 'high-price' being added, which makes four total. Seven life attitude measures of life purpose, life control, will to meaning, goal seeking, future mean to fulfill, life satisfaction, and religiosity were applied. Finally, such socio-psychological measures as age, gender, marital status, income, and age-gap between couples were assumed to function as moderators. With 430 valid study samples, ages from 20s to 50s, with more females(316) than males(114), with average personal possessions of 5 genuine and 9 counterfeit luxury brands, we conducted questionnaire survey. Results indicated that social-adjustive function is totally disappeared in the relationship due to current social trend of widespread consumptions on both genuine and counterfeit brands which in turn, make consumers feel less special on wearing or carrying them unlike in the past. Self-expressive function and rationality-consumptive functions act as strong catalysts for genuine brand consumption and counterfeit brand consumption, respectively. On consumers' decision-making styles, high-price sublation is the most powerful indicator anticipating counterfeit consumption, even more powerful than personal incomes. In life attitude, the overall model fit was not validated, and only life control and life satisfaction are proven to be significant on both genuine and counterfeit product consumptions. Employment of socio-psychological factors in the model improved understanding of users further. Young consumers tend to go for genuine products over counterfeits. Consumers in different income groups; low, medium and high, all significantly consume genuine products for reasons of different decision-making styles. The results indicated that consumers whose personal disposition is predisposed to consume products in the form of reflection of his or her personality, go only for genuine brands for quality reason, while consumers who rationally consume products for its function or usability, go only for counterfeits for high-price sublation reason. Meanwhile, both product users support for high-price orientation who are not well off.

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홍수량 예측 인공신경망 모형의 활성화 함수에 따른 영향 분석 (Impact of Activation Functions on Flood Forecasting Model Based on Artificial Neural Networks)

  • 김지혜;전상민;황순호;김학관;허재민;강문성
    • 한국농공학회논문집
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    • 제63권1호
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    • pp.11-25
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    • 2021
  • The objective of this study was to analyze the impact of activation functions on flood forecasting model based on Artificial neural networks (ANNs). The traditional activation functions, the sigmoid and tanh functions, were compared with the functions which have been recently recommended for deep neural networks; the ReLU, leaky ReLU, and ELU functions. The flood forecasting model based on ANNs was designed to predict real-time runoff for 1 to 6-h lead time using the rainfall and runoff data of the past nine hours. The statistical measures such as R2, Nash-Sutcliffe Efficiency (NSE), Root Mean Squared Error (RMSE), the error of peak time (ETp), and the error of peak discharge (EQp) were used to evaluate the model accuracy. The tanh and ELU functions were most accurate with R2=0.97 and RMSE=30.1 (㎥/s) for 1-h lead time and R2=0.56 and RMSE=124.6~124.8 (㎥/s) for 6-h lead time. We also evaluated the learning speed by using the number of epochs that minimizes errors. The sigmoid function had the slowest learning speed due to the 'vanishing gradient problem' and the limited direction of weight update. The learning speed of the ELU function was 1.2 times faster than the tanh function. As a result, the ELU function most effectively improved the accuracy and speed of the ANNs model, so it was determined to be the best activation function for ANNs-based flood forecasting.

언어적 표현을 통해 본 주거의 개념에 대한 탐구적 연구 - 중산층 아파트 거주주부를 대상으로 - (An Exploratory Study on Home Concept through Verbal Expression of Middleclass Apartment Residents)

  • 이연숙
    • 한국주거학회논문집
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    • 제1권1호
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    • pp.49-64
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    • 1990
  • Studies on housing concept currently activated by environmental psychology are in its early stage of developement. The trends can be characterized as case oriented, phenomenological, and exploratory. The purpose of this research was to explore empirically the housing concept from residents living in multi family housing complex through their verbal expressions. Subjects were 63 housewives of middle class households in Junggae area. Interview technique with open questions about housing concept and images was used. The responses were analyzed using content analysis in which episode was the analysis unit. Relaxation appeared the most important aspect of housing concept This seemed to imply the need for escaping from the modern city life with too much stimulus or stress. Answers on specific images considered desirable to keep and continue from past traditional housing to future housing showed their strong need for natural green environment such as garden and park. This supported the concept of relaxation as a major function of modern housing and showed a specific alternative mean to satisfy the relaxation concept.

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Mid-term (2009-2019) demographic dynamics of young beech forest in Albongbunji Basin, Ulleungdo, South Korea

  • Cho, Yong-Chan;Sim, Hyung Seok;Jung, Songhie;Kim, Han-Gyeoul;Kim, Jun-Soo;Bae, Kwan-Ho
    • Journal of Ecology and Environment
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    • 제44권4호
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    • pp.241-255
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    • 2020
  • Background: The stem exclusion stage is a stage of forest development that is important for understanding the subsequent understory reinitiation stage and maturation stage during which horizontal heterogeneity is formed. Over the past 11 years (2009-2019), we observed a deciduous broad-leaved forest in the Albongbunji Basin in Ulleungdo, South Korea in its stem exclusion stage, where Fagus engleriana (Engler's beech) is the dominant species, thereby analyzing the changes in the structure (density and size distributions), function (biomass and species richness), and demographics. Results: The mean stem density data presented a bell-shaped curve with initially increasing, peaking, and subsequently decreasing trends in stem density over time, and the mean biomass data showed a sigmoidal pattern indicating that the rate of biomass accumulation slowed over time. Changes in the density and biomass of Fagus engleriana showed a similar trend to the changes in density and biomass at the community level, which is indicative of the strong influence of this species on the changing patterns of forest structure and function. Around 2015, a shift between recruitment and mortality rates was observed. Deterministic processes were the predominant cause of tree mortality in our study; however, soil deposition that began in 2017 in some of the quadrats resulted in an increase in the contribution of stochastic processes (15% in 2019) to tree mortality. The development of horizontal heterogeneity was observed in forest gaps. Conclusions: Our observations showed a dramatic shift between the recruitment and mortality rates in the stem exclusion stage, and that disturbance increases the uncertainty in forest development increases. The minor changes in species composition are likely linked to regional species pool and the limited role of the life-history strategy of species such as shade tolerance and habitat affinity. Our midterm records of ecological succession exhibited detailed demographic dynamics and contributed to the improvement of an ecological perspective in the stem exclusion stage.

장기인구성장에 따른 주택 및 주거환경 (Population Growth and Housing)

  • 정희수
    • 한국인구학
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    • 제8권1호
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    • pp.65-86
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    • 1985
  • Korean population is ecpected to reach about 50 million by year 2000. And per capita GNP might attain the $5,000 level. This is bound to have profound impact on housing. For one thing, population and income growth will accelerate new household formation thus increasing new housing needs. On the other, changes in the housing preference function in association with income growth and new way of life would mean increasing demand for better dwelling environment. In addition, by year 2000, there will be many more elderly households necessitating new approaches to housing. The question is whether or not Korea could cope with new housing perspectives. If Korean housing has made in the past some progress in housing quality, it has not been able to tackle the mounting housing shortage. This is attributable to the concentration of effective housing demand in the hands of upper income groups in association with skewed income distribution and sustained dwelling price hike. Korea needs some basic changes in housing policy. The public sector should produce much more small dwellings either for sales or renting. Second, mortgage loans should be expanded so as to increase the access to housing. Third, every thing must be done to cut down the dwelling price through tax cut, relaxation of some requlations, cyclical stabilization of dwelling construction and loan subsidies.

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월 자료로부터 일 강수자료 생성을 위한 Markov 연쇄 및 감마분포 모수 추정 (Estimation of Markov Chain and Gamma Distribution Parameters for Generation of Daily Precipitation Data from Monthly Data)

  • 문경환;송은영;손인창;위승환;오순자;현해남
    • 한국농림기상학회지
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    • 제19권1호
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    • pp.27-35
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    • 2017
  • 이 연구는 우리나라를 대상으로 일 강우자료를 생성하는 방법을 모색하기 위하여 진행되었다. 우선 전국 23개 기상관서의 과거 30년간의 일 강우자료를 수집하여 기상생성방법으로 많이 이용되는 조건부 확률을 이용한 Markov 연쇄와 감마 분포 함수를 결합하는 방법을 적용하여 본 결과 관측자료와 유사한 일 강우자료를 생성하였고, 23개 지점별로 강우특성을 나타내는 4종의 모수를 계산할 수 있었다. 또한 새로운 방법을 이용하여 지점의 강우특성을 나타내는 모수는 월 강우량으로부터 추정할 수 있었고, 이를 적용하여 1981~2010년, 2011~2015년 두 기간을 대상으로 일 강우자료를 생성하여 기존의 관측자료와 비교한 결과 매우 유사한 분포를 나타내는 것을 알 수 있었다. 따라서 월 강우량 자료를 이용하여 강우특성모수를 산출하고 이로부터 일 강우자료를 생성하는 조건부 확률과 감마 분포 함수를 결합한 방법은 농업의 기후변화 영향과 수자원의 연구에 실용적으로 이용될 것으로 기대된다.

VVVF 도시철도 차량의 신뢰성 평가 시스템 개발에 관한 연구 (A Study on Development of the Reliability Evaluation System for VVVF Urban Transit)

  • 배철호;김성빈;이호용;장석화;서명원
    • 한국자동차공학회논문집
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    • 제13권5호
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    • pp.7-18
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    • 2005
  • Over the past twenty years, the maintenance system has been developed and its importance has been increased. For the effective maintenance of the urban transit, we have developed the maintenance system based on the concept of RCM(Reliability Centered Maintenance). RCM analysis is a systematic approach to developing a cost-effective maintenance strategy based on the various components's reliability of the system in question. It is performed according to process that includes the following steps; definition of function and functional failures of the systems, construction of RB D(Reliability Block Diagram), performance of FMEA(Failure Modes & Effects Analysis) and calculation of the reliability index. The final process of RCM is to determine appropriate failure maintenance strategies. This paper aims to define the procedure of maintenace based on the concept of RCM for urban transit. The key for a successful maintenance system is an automated scheduling to the maximum extent possible and timely executions. The developed system issues maintenance plan and repair request based on analyzed data and maintenance experience.

지리산국립공원 아고산대 주요 수종(주목, 잣나무, 구상나무, 신갈나무)에 대한 산소동위원소연대기 작성 및 기후와의 관계 분석 (Establishing Tree Ring δ18O Chronologies for Principle Tree Species (T. cuspidata, P. koraiensis, A. koreana, Q. mongolica) at Subalpine Zone in Mt. Jiri National Park and Their Correlations with The Corresponding Climate)

  • 서정욱;정현민;;최은비;박준희;이광희;김요정;박홍철
    • Journal of the Korean Wood Science and Technology
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    • 제45권5호
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    • pp.661-670
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    • 2017
  • 지리산 아고산대 주요 침엽수(주목, 잣나무, 구상나무)와 신갈나무를 이용하여 50년간의 산소동위원소연대기(1966~2015)를 작성하였다. 산소동위원소연대기 작성은 크로스데이팅(cross-dating) 결과가 우수한 4본을 각 수종에서 선발하여 실시하였다. 동일 수종 내 임목 간 산소동위원소연대기의 상관분석 결과 모두 유의성(p < 0.001) 높은 상관이 있는 것으로 확인되었으며, EPS도 0.85 이상이었다. 동일 수종 내 임목 간 상관분석뿐만 아니라 수종간 상관분석에서도 유의성(p < 0.001) 높은 상관관계가 확인되었다. 기후요소(강수량, 기온)와 산소동위원소와의 관계를 조사하기 위한 반응함수 분석에서 주목은 당년 5월 강수량과 유의성 있는 부의 상관을 보였으며, 구상나무는 4월 강수량과 유의성 있는 부의 상관을 보였다. 향후 주목과 구상나무에 대한 장기간의 산소동위원소연대기가 작성된다면 과거 측정하지 못한 장기간의 4월과 5월 강수량 복원이 가능할 것이다.

국균종의 임상적 고찰 (Clinical Characteristics of Aspergilloma)

  • 김기업;길효욱;이석호;김도진;나문준;어수택;김용훈;박춘식
    • Tuberculosis and Respiratory Diseases
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    • 제52권1호
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    • pp.46-53
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    • 2002
  • 연구배경 : 폐 국균종은 우리나라에서 비교적 흔히 볼 수 있는 만성적인 진균감염으로서 방사선학적으로는 air-crescent를 특징으로 하는 질환이다. 객혈이 주요 증상이고, 주된 선행질환으로 폐결핵이 알려져 있다. 진단은 방사선학적으로 공동내 고형 및 원형의 종괴가 공동의 벽과 분리되어 존재하는 것이며 혈청학적 검사가 진단에 도움이 된다. 치료에서는 항진균제를 포함한 보존적 치료와 수술이 있는데, 최근에는 환자의 전신상태가 양호한 경우 수술이 선호되는 경향을 보인다. 저자들은 국균종이 의심되는 환자 중 수술로서 확진이 되거나 국균항체 양성으로 판정된 환자의 임상 양상에 대하여 알아보고자 하였다. 대상 및 방법 : 1995년 1월부터 2000년 12월까지 문진과 진찰소견, 단순 흉부 방사선 검사와 전산화단층촬영에서 국균종이 의심되는 58례 중 수술을 하여 확진된 경우 9례, 기관지 내시경 및 경피적 침 생검과 국균종에 대한 항제 양성을 보이는 13례를 대상으로 후향적 분석을 하였다. 결 과 : 1) 기저질환으로는 폐결핵이 16례 (72.7%)였으며, 이중 현재 결핵균 동정에서 비결핵항산균이 3례가 있었다. 완치판정을 받은 결핵환자에서 국균종을 진단할 때까지 기간은 $5.91{\pm}5.72$년이었다. 기타로 폐농양 2례 (9.1%), 기관지확장증 1례 (4.5%), 폐기종 1례 (4.5%), 폐내 기저질환이 없는 경우 2례 (9.1%)였다. 호흡기계이외의 질환으로는 빈번한 음주력(22.7 %)과 당뇨(13.6%)였다. 2) 주소로는 객혈이 16례(72.7%)로 가장 많았으며, 진찰소견은 호흡음에서 이상을 발견할 수 없는 경우가 가장 많았다. 검사실 소견에서는 적혈구 침강속도의 증가 외에 특이사항을 발견할 수 없었다. 방사선 소견은 전산화단층촬영이 도움이 되었으며 주된 소견으로는 "fungal ball"과 "air-meniscus sign"이었다. 호발부위는 폐 상엽, 특히 후분절이 가장 많은 빈도를 보였다. 3) 기관지 동맥 색전술의 효과를 확인 할 수 없었으며, 수술방법은 엽절제술 (lobectomy)이 가장 많았고 수술 및 수술의 경과 중 특기할 만한 합병증이나 사망은 없었다. 추적접사에서 사망률은 13.6%였으나 국균종에 의한 것은 아니였다. 결 론 : 국균종은 결핵 및 기타 공동을 형성하는 질환에서 호발하는 질환이며 다량의 객혈이나 빈번한 객혈이 문제가 될 수 있다. 전신상태가 양호한 환자에서 수술이 추후에 발생하는 객혈을 비롯한 합병증 예방에 최선의 치료이지만, 전신상태가 불량하고 폐기능의 장애가 있는 환자에 대한 합병증 예방 및 근치적 치료에 여러 방법이 대두되는 바 좀더 적극적인 접근이 요구된다 하겠다.