• 한국식품영양학회지
• /
• 제25권1호
• /
• pp.205-213
• /
• 2012

This study investigated the life cycle of menus and made suggestions on the appropriate time for when new menus should be developed. For this purpose, a total of 636 customers who visited 'T' Restaurant more than 25 times in the past three years were used for analysis. After estimating product life cycles based on sales and selling period, an empirical study was conducted. In terms of product life cycle, a growth stage was observed in the category of pasta and pizza in both stores A and B, whereas sales in the rice category stayed constant. Regarding trend in seasonal sales, a big difference was detected between the two stores. While store A was already in the decline stage of the life cycle in all menu categories, store B remained in the growth stage. In terms of menu life cycle, the product life cycle of long-lived products was observed in the pasta category in both stores A and B. While the pizza category was in the growth stage, the product life cycle of long-lived products was observed in the rice category. It is expected that the results of this study could be useful in development of new menus and product life cycle management to fulfill diverse customer needs in the dining-out business.

• 한국해양공학회지
• /
• 제24권6호
• /
• pp.97-102
• /
• 2010

This paper deals with the variability of short term creep rupture time based on previous creep rupture tests and the statistical methodology of the creep life prediction. The results of creep tests performed using constant uniaxial stresses at 600, 650, and $700^{\circ}C$ elevated temperatures were used for a statistical analysis of the inter-specimen variability of the short term creep rupture time. Even under carefully controlled identical testing conditions, the observed short-term creep rupture time showed obvious inter-specimen variability. The statistical aspect of the short term creep rupture time was analyzed using a Weibull statistical analysis. The effect of creep stress on the variability of the creep rupture time was decreased with an increase in the stress level. The effect of the temperature on the variability also decreased with increasing temperature. A long term creep life prediction method that considers this statistical variability is presented. The presented method is in good agreement with the Lason-Miller Parameter (LMP) life prediction method.

• 대한기계학회논문집A
• /
• 제30권8호
• /
• pp.976-984
• /
• 2006

Time-temperature superposition has been studied to determine the long-term fatigue life over millions of cycles for glassy polymers. π le superposition is supposed to make an accelerated lifetime testing (ALT) technique possible. Dog-bone shaped specimens made of carbon filled Polycarbonate (PC) were tested under fatigue, based on the stress-lifetime approach (S-N curve). Fatigue-induced localized yield-like deformation is considered as the defect leading to fatigue and its evolution behavior is characterized by a modified energy activation model in which temperature is considered as fatigue acceleration factor. This model allows the reduced time concept to account for effects of different temperature in short-term fatigue data to determine long-term fatigue life through the use of time-temperature superposition that is applicable under a low frequency and isothermal conditions. The experimental results validated that the proposed technique could be a possible method for accelerated lifetime testing (ALT) of time-dependent polymeric materials.

• 한국콘텐츠학회논문지
• /
• 제12권6호
• /
• pp.518-529
• /
• 2012

유럽의 통합은 1991년 12월 마스트리히트에서 유럽연합조약을 처음 체결하면서 시작되었다. 근대 민족 국가의 요람이라고 할 수 있는 유럽은 현재 각국들의 사회경제적 통합은 물론 정치적 분야에서도 단일 유럽을 실현해 왔다. 이러한 가운데 유럽연합의 새로운 통합성장동력을 개발하기 위한 평생교육정책은 무엇보다도 사회경제적 환경 변화에 대비 할 수 있는 교육적 대응이 필요하다고 보고 있다. 특히 평생교육분야의 협력과 통합발전에 있어서는 다양성과 상호 조절을 통한 효율성의 조화를 이루어야 하는 중요한 과제를 안고 있다고 본다. 그러나 그들의 노력에도 불구하고 2008년 이후 유럽연합의 몇몇 국가들은 경제 침체로 인하여 국가재정의 위기를 맞이하였으며, 급기야 유럽전체의 재정위기로 까지 영향을 미치고 있다. 이와 같은 위기는 현재 유럽연합의 사회경제적 통합을 흔들고 있다. 본 연구에서는 유럽연합의 사회경제적 통합을 위한 평생교육 체제구축 및 정책 추진 현황을 살펴보고, 유럽연합에 속한 국가들 간의 성인평생교육 참여율이 1인당 국민소득과 어떠한 관련성이 있는지 분석하고자 하였다. 그리고 유럽연합의 경제위기 속에서 회원국 간의 사회경제적 통합이 지속 가능할 수 있을지를 통합적 평생교육체제의 문제점을 중심으로 알아보았다. 또한 이를 통하여 우리나라 평생교육의 새로운 패러다임 전환과 정책 수립 및 발전 방향 제시에 시사점을 도출하고자 하였다.

• 대한기계학회논문집
• /
• 제17권6호
• /
• pp.1321-1329
• /
• 1993

본 연구에서는 이들보다 매우 간단한 IS법, 즉 초기 변형률법(ISM: initial strain method)에 의한 크리프 수명예측식을 고안하여, 현재 화력발전용 고압 로터강 에 사용되고 있는 1%Cr-Mo-V강과 발전소 효율향상을 위해 최근 국내최초로 개발된 12% Cr강에 대하여 도출하였고, 이 도출식이 앞에서 언급한 여러 파라메트에 의한 결과와 비교 평가하여 장시간 강도 및 수명예측식으로 사용될 수 있음을 입증하였다.

• 응용통계연구
• /
• 제2권2호
• /
• pp.61-78
• /
• 1989

정상조건에서 수명이 상당히 긴 개체의 생명검사(Life Test)를 현실적으로 수행하기 위하여 제안된 충격생명검사에 관하여 고찰하였다. 생명검사의 결과로 얻는 자료의 통계적 분석을 위하여 이미 제안된 모형의 검토와 이들을 일면 포함하는 모형을 제시하고 그에 따르는 통계적 추론 과정을 최대우도추정법과 가중최소자승법을 사용하여 토의하였다. 한편 검사를 계획할 때 발생하는 실험설계의 문제를 검토하고 단순 계단적 충격검사에서 잘려진 자료(Consored Data)를 포함한 경우를 연구하였다.

• 패션비즈니스
• /
• 제27권4호
• /
• pp.1-20
• /
• 2023

This study proposes the practical design elements of sustainable fashion by understanding the values of the MZ generation and analyzing the design characteristics that can extend the life of clothing. The theoretical concept of sustainable fashion through previous studies was reviewed and in-depth interviews were conducted with the MZ generation on "design characteristics of clothes that they have actually used for a long time." The result was drawn by approaching the constant comparison method through the qualitative methodology. As a result of the study, the design characteristics of clothes that can be worn for a long time are as follows. First, simple design pursues simplicity that is not excessive to the essential characteristics of clothes. Second, sturdy material is durable and not easily damaged. The clothing storage method and laundry method were also factors that could extend the life of the garment. Third, emotional design is a design that fits well with your mood and body type and gives a special meaning to your emotions. This study is meaningful in suggesting elements necessary for extending the life cycle of clothing and providing basic data that can be applied to the practical design steps of the fashion industry.

• 산경연구논집
• /
• 제9권10호
• /
• pp.83-89
• /
• 2018

Purpose - The purpose of this study examines when the optimism impact on financial asset price forecasting and the boundary condition of optimism in the financial asset price forecasting. People generally tend to optimistically forecast their future. Optimism is a nature of human beings and optimistic forecasting observed in daily life. But is it always observed in financial asset price forecasting? In this study, two factors were focused on considering whether the optimism that people have applied to predicting future performance of financial investment products (e.g., mutual fund). First, this study examined whether the degree of optimism varied depending on the direction of the prior price trend. Second, this study examined whether the degree of optimism varied according to the forecast period by dividing the future forecasted by people into three time horizon based on forecast period. Research design, data, and methodology - 2 (prior price trend: rising-up trend vs falling-down trend) × 3 (forecast time horizon: short term vs medium term vs long term) experimental design was used. Prior price trend was used between subject and forecast time horizon was used within subject design. 169 undergraduate students participated in the experiment. χ² analysis was used. In this study, prior price trend divided into two types: rising-up trend versus falling-down trend. Forecast time horizon divided into three types: short term (after one month), medium term (after one year), and long term (after five years). Results - Optimistic price forecasting and boundary condition was found. Participants who were exposed to falling-down trend did not make optimistic predictions in the short term, but over time they tended to be more optimistic about the future in the medium term and long term. However, participants who were exposed to rising-up trend were over-optimistic in the short term, but over time, less optimistic in the medium and long term. Optimistic price forecasting was found when participants forecasted in the long term. Exposure to prior price trends (rising-up trend vs falling-down trend) was a boundary condition of optimistic price forecasting. Conclusions - The results indicated that individuals were more likely to be impacted by prior price tends in the short term time horizon, while being optimistic in the long term time horizon.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 B
• /
• pp.1382-1384
• /
• 2002

The flooded type battery is used for solar lighting system. Because the characteristic of flooded type battery is the short life time, the maintenance cost is high. So the using flooded type battery in this system is inappropriate. The valve regulated lead acid batter.(VRLA) is the maintenance free and cycle service purpose. This paper presents the development of control system and monitoring system to applied VRLA battery for maintenance free and long life time in system.

• 한국해양공학회지
• /
• 제15권3호
• /
• pp.43-48
• /
• 2001

In this paper, the real-time prediction of high temperature creep strength and creep for nickel-based superalloy Udimet 720 (high-temperature and high-pressure gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and 704$^{\circ}C$. The predictive equation of ISM creep has better reliability than that of LMP and LMP-ISM, and its reliability is getting better for long time creep prediction ($10^3~10^5$h).