• Title/Summary/Keyword: K-factor approach

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A Study on the Relationships between the Attitudes of University Students toward Money and the Attributes of Choosing Family Restaurants (대학생의 금전에 대한 태도에 따른 패밀리 레스토랑 선택 속성에 관한 연구)

  • Jung, Hyo-Sun;Yoon, Hye Hyun
    • Culinary science and hospitality research
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    • v.14 no.2
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    • pp.99-114
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    • 2008
  • The purpose of this study is to examine the relationships between each type of attitudes toward money and the attributes of choosing family restaurants. A self-administrated questionnaire was completed by 387 students, and data were analysed by frequency, factor, reliability and canonical correlation. Seven factors were obtained from factor analysis of attitudes toward money; Factor 1 "power", Factor 2 "obsession", Factor 3 "retention", Factor 4 "achievement", Factor 5 "anxiety", Factor 6 "distrust", and Factor7 "evaluation". The attributes of family restaurant choice were extracted into six factors: Factor 1 "quality of food", Factor 2 "restaurant event", Factor 3 "interior environment", Factor 4 "value of food", Factor 5 "convenience for approach", and Factor 6 "employees' service". Canonical correlation analysis showed three significant functions. Canonical function 1 showed that the attitudes of considering the power of money, its retention and achievement were indicated to have significantly positive relationships with the quality of food in the attributes of choosing family restaurants. Canonical function 2 showed that significantly negative relationships between distrust and restaurant events and convenience for approach. Canonical function 3 also showed that significantly positive relationships between obsession and anxiety and the interior of restaurants and employees' service, and significantly negative relationships between evaluation and the interior of restaurants and employees' service.

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Supply Chain Network Design Considering Environmental Factor and Transportation Types

  • Yun, YoungSu
    • Journal of Korea Society of Industrial Information Systems
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    • v.23 no.5
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    • pp.33-41
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    • 2018
  • Most important thing when designing and implementing a supply chain network is to consider various problems which may occur in real world situation. In this paper, we propose a supply chain network considering two problems (environmental factor and transportation types) under real world situation. CO2 emission amount as environmental factor is considered since it is usually generated from production and transportation processes. Normal delivery, direct delivery and direct shipment as transportation types are also considered since many customers ask various transportation types for delivery or shipment of their products under on-line or off-line purchase environment. The proposed supply chain network considering environmental factor and transportation types is represented in a mathematical formulation and implemented using hybrid genetic algorithm (HGA) approach. In numerical experiments, several scales of supply chain networks are presented and implemented using HGA approach. The performance of the HGA approach is compared with those of some conventional approaches under various measures of performance. Finally, it is proved that the performance of the HGA approach is superior to those of the others.

Novel approach for early damage detection on rotor blades of wind energy converters

  • Zerbst, Stephan;Tsiapoki, Stavroula;Rolfes, Raimund
    • Smart Structures and Systems
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    • v.14 no.3
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    • pp.419-444
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    • 2014
  • Within this paper a new approach for early damage detection in rotor blades of wind energy converters is presented, which is shown to have a more sensitive reaction to damage than eigenfrequency-based methods. The new approach is based on the extension of Gasch's proportionality method, according to which maximum oscillation velocity and maximum stress are proportional by a factor, which describes the dynamic behavior of the structure. A change in the proportionality factor can be used as damage indicator. In addition, a novel deflection sensor was developed, which was specifically designed for use in wind turbine rotor blades. This deflection sensor was used during the experimental tests conducted for the measurement of the blade deflection. The method was applied on numerical models for different damage cases and damage extents. Additionally, the method and the sensing concept were applied on a real 50.8 m blade during a fatigue test in the edgewise direction. During the test, a damage of 1.5 m length was induced on the upper trailing edge bondline. Both the initial damage and the increase of its length were successfully detected by the decrease of the proportionality factor. This decrease coincided significantly with the decrease of the factor calculated from the numerical analyses.

A Study about Measurement Model of Long Term Performance in Stock Split (주식분할의 장기성과 측정 모델에 대한 연구)

  • Shin, Yeon-Soo
    • The Journal of Information Technology
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    • v.9 no.3
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    • pp.77-89
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    • 2006
  • The event study analyzes returns around event date at a time. Event study provides estimation periods and cumulative returns. Stock split announcements are generally associated with positive abnormal returns. It is important to investigate the responses of stocks to new information contained in the announcements of stock splits. So It is important to study the long term performance in the case of Stock Split. This Study forced to two approach method in evaluating the performance, the event time portfolio approach and calendar time portfolio approach. The event time portfolio approach exists the CAR model, BHAR model and WR model. And the calendar time portfolio approach has the 3 factor model, 4 factor model, CTAR model, and RATS model.

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Stability Evaluation of Piles under Negative Skin Friction by the LRFD Approach (LRFD 설계법에 의한 부마찰력이 작용하는 말뚝의 안정성 평가)

  • Cho, Chun-Hwan;Kim, Woong-Kyu;Lee, Cheol-Woo;Gang, In-Cheol;Kim, Young-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.17-24
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    • 2005
  • Recently construction activities increase in reclaimed onshore areas. It is therefore considered an important factor for the design of pile foundation with problems in terms of settlements due to soft grounds. Nevertheless the design of piles for negative skin friction(or downdrag forces) is probably poorly understood by many engineers. It is mainly because the most of design specification give a way to design pile foundation in bearing capacity aspect although the negative skin friction is related to settlement(downdrag). Under LRFD(load resistance factor design) approach it is to separately consider ultimate limit state and serviceability limit state. This paper discusses LRFD approach to the design of piles for negative skin friction and compares this approach to traditional design approach. And also a case history is analyzed in that point of view.

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A Study of Effects of Stock Option on Firm's Performance (주식매수선택권이 기업성과에 미친 영향에 대한 연구)

  • Shin, Yeon-Soo
    • The Journal of Information Technology
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    • v.9 no.4
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    • pp.75-85
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    • 2006
  • This study is to test the influence of stock option granting information on the firm's performance. The important issue in stock option is that agent cost is the important determinant factor for the long term performance. The agent cost arises between the manager and shareholders. So many study are concentrated in diminishing the agent cost, and develop some substitute tools to measure the agent cost. The event study about stock option analyzes returns around event date at a time. Event study provides estimation periods and cumulative returns. Announcements about stock option are generally associated with positive abnormal returns in short term period, but not showing positive effect in long term period. It is important to investigate the responses of stocks to new information contained in the announcements of stock option. Therefore it is important to study the long term performance in the case of stock option. The event time portfolio approach exists the CAR model, BHAR model and WR model. And the calendar time portfolio approach has the 3 factor model, 4 factor model, CTAR model, and RATS model. This study is forced to develop and arrange two approach method in evaluating the performance, the event time portfolio approach and calendar time portfolio approach.

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Effects of Stacking Sequence on the Application of the Single Specimen Technique to CLS Specimen (단일시편방법의 CLS 시편 적용시 적층성이 미치는 영향)

  • Lee, Gyeong-Yeop;Yang, Jun-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.11 s.170
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    • pp.1952-1959
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    • 1999
  • The work factor approach, so-called single specimen technique could be used to determine energy release rate from a single test record for unidirectional CLS specimen. In the present study, the work factor approach was extended to determine the mixed-mode fracture toughness of multi-directional graphite/epoxy laminated composites. Multi-directional CLS specimens were used for fracture tests. The stacking sequences used for the lap and the strap were $[90_2/0_2]_s/[0_4/90_4]_s$ and $[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$, respectively. For both cases, the fracture toughness determined from the work factor approach was compared with that determined from the compliance method. It was found that both methods produced fracture toughness within a maximum 15% difference for each stacking sequence. The fractography analysis also showed that the fiber bridging occurred for$[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$ case while it did not occur for $[90_2/0_2]_s/[0_4/90_4]_s$ case.

Contributions of Public Investment to Economic Growth and Productivity

  • HAN, SUNGMIN
    • KDI Journal of Economic Policy
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    • v.39 no.4
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    • pp.25-50
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    • 2017
  • Whereas a large variety of previous studies show mixed results regarding the relationship between public investment and economic outcome, several studies have been conducted on related issues in Korea. The present study deals with the effect of public investment in Korea on economic growth and productivity. Using administrative data, it exploits three different methodologies: the total factor productivity approach, production function approach, and stochastic frontier production function approach. The results of this study show that public investment has a statistically significant effect on economic growth. However, it contributes little to enhance productivity. It is explained that there exists inefficiency of production in the Korean economy. These findings indicate that public investment has played a central role in the direct input factor and not in indirect role in Korea. Thus, it is necessary for public investment policies to concentrate on enhancing the efficiency of the Korean economy.

Reliability analysis-based safety factor for stability of footings on frictional soils

  • Parviz Tafazzoli Moghaddam;Pezhman Fazeli Dehkordi;Mahmoud Ghazavi
    • Geomechanics and Engineering
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    • v.33 no.6
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    • pp.543-552
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    • 2023
  • The design of foundations based on a deterministic approach may not be safe and reliable occasionally, since soils sometimes show considerable spatial variability, and thus, significant uncertainties in turn affect the estimation of footing bearing capacity. The design of footing on cohesionless stratums on the basis of reliability analysis has not received much attention. This paper performs two-dimensional random finite difference analyses of shallow strip footings on a spatially variable frictional soil considering correlation structure. Friction angle (ϕ) is considered as a log-normally distributed random variable and Monte Carlo Simulation is then performed to determine the statistical response based on the random fields. A new approach reliability-based safety factor is defined based on various reliability levels by considering the coefficient of variation of ϕ and correlation length in both the horizontal and vertical directions. The comparison of the probabilistic safety factor and the conventional one illustrates the limitations of the deterministic safety factor and provides insight into how the heterogeneity of soils properties affects the required safety factor. Results show that the conventional safety factor of 3 can be conservative in some cases, especially for soil with low values of mean ϕ and COVϕ.

ZVZCS Single-Stage Power Factor Corrected Converter (영전압, 영전류 스위칭 1단 방식 역률 보상 AC/DC 컨버터)

  • Kang, Feel-Soon;Park, Sung-Jun;Kwon, Soon-Jae;Kim, Cheul-U
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.1348-1350
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    • 2000
  • Zero-voltage and zero-current switched single-stage approach with high power factor is presented to reduce the switching losses and to achieve sinusoidal, unity power factor input currents. This single-stage approach, which combines a boost converter used as PFC with a half-bridge converter used as do to do conversion into one power stage, has a simple structure and low cost. At the same time, since the switches of the proposed converter are designed to be turned on at zero-voltage and off at zero-current, the switching losses could be reduced considerably. Detailed analysis and experimental results are presented on the proposed converter, which is operated at constant switching frequency and in discontinuous conduction mode.

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