• Title/Summary/Keyword: early maturity

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An Ethnographic Case Study on the Early Motherhood (초기 모성경험에 관한 질적 연구)

  • Noh, Young-Joo
    • Journal of Families and Better Life
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    • v.18 no.3 s.47
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    • pp.71-84
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    • 2000
  • The purpose of this study is to analyze the structure of maternal experiences. This study applies ethnographic case study, interview data were collected through in-depth interviews of 10 key interviewees. Findings were as follows: (1) Experiences of the body were about creating a new being through the pain of giving a birth and differed according to woman's self-evaluation of identity. (2) Child-rearing experiences marked a shift of position from a child to a parent. Interviewees experienced the hardhsip of life as a mother, its meanings differed according to the social context of interviewees. Child-rearing experiences meant a process of personal maturity. (3) Mother-child relationship shaped by child-rearing experiences, is a process of building meanings. It led to empathy and reinterpretation of her mother's life.

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A Study on the Strength Properties of Mortar Under Various Types and Contents of Accelerators for Freezing Resistance (내한촉진제의 종류 및 혼입양 변화에 따른 모르터의 강도특성에 관한 연구)

  • Lee, Sang-Soo;Won, Cheol;Park, Sang-Joon;Kim, Dong-Seok
    • Journal of the Korea Institute of Building Construction
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    • v.2 no.2
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    • pp.151-156
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    • 2002
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than constant temperature condition in same maturity.

The Effect on Strength Development of Cement Mortar using Accelerators for Freezing Resistance with the Curing Condition (양생조건이 내한촉진제를 사용한 시멘트 모르타르의 강도증진에 미치는 영향에 관한 연구)

  • Won, Cheol;Kim, Dong-Seok;Park, Sang-Joon;Lee, Sang-Soo;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.533-536
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    • 2001
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolving these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than fixed temperature condition in same maturity.

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Themal Stress Analysis of the Heat of Hydration Considering Pipe-Cooling (파이프 쿨링을 고려한 수화열 해석기법에 관한연구)

  • 긴진근;김국한;최계식;양주경;최고일
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.04a
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    • pp.274-279
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    • 1995
  • The heat of hyderation of cement causes the internal temperature rise and volume change at early age, paticular in massive concrete structures. As the results of the temperature rise and extenal restraint conditions, the themal stress may induce cracks in concrete. Therefore various techenuques of the themal stress control of the mass concrete has been widely used. One of these techniques is pipe-cooling which is considered in this study. The objective of this paper is to develop finite element program which is capable of simulating the temperature history and the thermal stress considering pipe-cooling, creep and the modified elastic modulus dud to maturity effect.

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Engineering Properties of Concrete Incorporating Cement Kiln Dust with W/B and Fluidity (W/B 및 유동성 변화에 따른 시멘트 킬른더스트 혼입 콘크리트의 공학적 특성)

  • Joo, Eun-Hi;Shon, Myeong-Soo;Cha, Cheon-Soo;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.628-631
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    • 2004
  • In this paper, mechanical properties of concrete incorporating CKD are discussed with W/B and fluidity. For setting properties, an increase in W/B retarded setting time greatly in $5^{\circ}C$, while accelerated in $20^{\circ}C$. For fluidity, an increase in slump delayed the setting time with dosage of SP agent. The presence of CKD has little influence on setting time compared with plain concrete. For compressive strength, an increase in maturity enhanced compressive strength. Fluidity had no relation to compressive strength. At low curing temperature, concrete with CKD has slight strength loss compared with plain concrete. However, remarkable strength loss at low curing temperature in early stage was not found, which can be applicable to low temperature environment concrete placing.

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The Static and Dynamic Growth Patterns of High-Tech Ventures in Korea

  • Park, Sangmoon;Bae, Zong-Tae
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2001.10a
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    • pp.233-236
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    • 2001
  • This study explores on the static and dynamic growth patterns of high-tech ventures in Korea. We developed an integrative framework with target market (local vs. global), product/market maturity (existing vs. emerging), and technological capability (follower vs. pioneer). We also identified seven new ventures strategies as follows: i) reactive imitation, ii) proactive localization, iii) import substitution, iv) creative imitation, v) early market-entry, vi) global niche, and vii) global innovation. With five successful Korean new ventures, we found different competitive behaviors and performance among new venture strategic types. This study also observed two different growth patterns: growth through strategic replication and growth through strategic change. It depends on whether they are pursuing similar strategy over time or different strategy within for growth. In addition, we found that creative imitation plays a stepping-stone role in two-step internationalization processes. Although this study is exploratory and needs more empirical studies, it can provide new ventures with meaningful guidelines for growth and internationalization with a dynamic perspective.

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Growth Data of Broiler Chickens Fitted to Gompertz Function

  • Duan-yai, S.;Young, B.A.;Lisle, A.;Coutts, J.A.;Gaughan, J.B.
    • Asian-Australasian Journal of Animal Sciences
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    • v.12 no.8
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    • pp.1177-1180
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    • 1999
  • This study describes the growth of broiler chickens to the two forms of Gompertz function for application in broiler production models. The first form is based on the estimated mature weight ($W_A$), while the second is based on the estimated hatch weight ($W_O$). Both equations gave identical estimation because they are mathematically identical. To fit the growth curve of commercial broilers that marketed at 35-42 days, it is unnecessary to keep broilers to near maturity (> day 140) to obtain growth data for deriving the Gompertz function. This date does not improve the curve fitting of the early growing period. Additionally, a high mortality and health problem occurred to this type of chicken after day 105.

Periodization in the History of Statistics

  • Jo, Jae-Keun
    • Communications for Statistical Applications and Methods
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    • v.11 no.1
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    • pp.31-47
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    • 2004
  • The history of statistics from the mid-seventeenth to the early twentieth century is considered and a scheme of periodization is proposed. In the first period(1650-1750), named 'the age of probability' in this paper, concept of probability emerged, and in the second period(1750-1820), named 'the age of error theory', statistical techniques such as the least square method are developed by astronomers and geodesists. Their techniques are supported theoretically by mathematicians like Laplace and Gauss in that period. The third period(1820-1880) is called 'the age of statistics(as a plural noun)' since statistical data played prominent roles in social sciences such as sociology, psychology. Finally the last period(1880- ), called 'the age of statistics(as a singular noun)', the discipline of statistics came to maturity both in theory and application.

A Thermal Conductivity Model for Hydrating Concrete Pavements

  • Jeong Jin-Hoon;Kim Nakseok
    • Journal of the Korea Concrete Institute
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    • v.16 no.1 s.79
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    • pp.125-129
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    • 2004
  • Hydrating concrete pavement is typically subjected to temperature-induced stresses that drive cracking mechanisms at early concrete ages. Undesired cracking plays a key role in the long-term performance of concrete pavement systems. The loss of support beneath the concrete pavement due to curling caused by temperature changes in the pavement may induce several significant distresses such as punch out pumping, and erosion. The effect of temperature on these distress mechanisms is both significant and intricate. Because thermal conductivity dominates temperature flow in hydrating concrete over time, this material property is back-calculated by transforming governing equation of heat transfer and test data measured in laboratory. Theoretically, the back- calculated thermal conductivity simulates the heat movements in concrete very accurately. Therefore, the back- calculated thermal conductivity can be used to calibrate concrete temperature predicted by models.