• ALGAE
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• 제29권3호
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• pp.203-215
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• 2014

As global warming continues over the coming century, marine organisms will experience a warmer, more acidic ocean. Although these stressors may behave antagonistically or synergistically and will impact organisms both directly (i.e., physiologically) and indirectly (i.e., through altered species interactions), few studies have examined the complexities of these effects in combination. To address these uncertainties, we examined the independent and combined effects of elevated temperature and $pCO_2$ on the physiology of the adult sporophyte stage of giant kelp, Macrocystis pyrifera, and the grazing of the purple sea urchin Strongylocentrotus purpuratus. While elevating $pCO_2$ alone had no effect on M. pyrifera growth or photosynthetic carbon uptake, elevating temperature alone resulted in a significant reduction in both. However, when M. pyrifera was grown under elevated temperature and $pCO_2$ together, growth and photosynthetic carbon uptake significantly increased relative to ambient conditions, suggesting an interaction of these factors on photosynthetic physiology. S. purpuratus held under future conditions generally exhibited reduced growth, and smaller gonads than urchins held under present-day conditions. However, urchins fed kelp grown under future conditions showed higher growth rates, partially ameliorating this effect. Feeding rates were variable over the course of the experiment, with only the first feeding rate experiment showing significantly lower rates for urchins held under future conditions. Together, these data suggest that M. pyrifera may benefit physiologically from a warmer, more acidic (i.e., higher $pCO_2$) ocean while S. purpuratus will likely be impacted negatively. Given that kelp-urchin interactions can be important to kelp forest structure, changes to either of these populations may have serious consequences for many coastal environments.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.714-719
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• 2017

입자의 크기와 형상을 제어할 수 있는 무기물질의 제한된 제조방법은 나노입자와, 의료, 전자부품, 반도체, 의약품, 화장품 등과 같은 다양한 산업영역에서 신물질을 개발하는데 중요한 요소이다. 탄산칼슘은 수많은 활용성 때문에 산업에서 가장 많이 주목받고 있는 물질중 하나이다. 용액결정화는 용액으로부터 녹아 있는 용질을 순수한 고체 형태로 추출하는 분리 공정으로, 화학공업과 제약공업 등에 널리 적용되어, 사용되고 있는 분리공정 중에 하나이다. 입자의 평균입경과 입도분포, 형상은 연속식 결정화기에서 중요한 요소이다. 본 연구에서는 연속식 결정화기에서 염화칼슘 공정으로 탄산칼슘 입자를 제조할 때, 정상상태에서 탄산칼슘 입자의 입도분포와 입경변화에 대하여 연구하였다. 입자의 평균입경과 입도분포는 입도분석기를 이용하여 측정하였으며, 입자의 형상과 크기는 전자현미경(SEM)을 이용하여 변화를 관찰하였다. 정상상태에서, 주입되는 시료의 농도와 혼합속도가 증가 할수록 입자의 평균입경은 증가하고, 제조되는 입자는 aragonite 보다는 calcite 입자가 주로 생성된다.

• 전기학회논문지
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• 제61권2호
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• pp.303-311
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• 2012

In this study, we introduce a dynamic process model as well as the design methodology of optimized fuzzy controller for its efficient application to vacuum production system to produce a semiconductor, solar module and display and so on. In a vacuum control field, PID control method is widely used from the viewpoint of simple structure and preferred performance. But, PID control method is very sensitive to the change of environment of control system as well as the change of control parameters. Therefore, it's difficult to get a preferred performance results from target system which has a complicated structure and lots of nonlinear factors. To solve such problem, we propose the design methodology of an optimized fuzzy PID controller through a following series of steps. First a dynamic characteristic of the target system is analyzed through a series of experiments. Second the process model is built up and its characteristic is compared with real process. Third, the optimized fuzzy PID controller is designed using genetic algorithms. Finally, the fuzzy controller is applied to target system and then its performance is compared with that of other conventional controllers(PID, PI, and Fuzzy PI controller). The performance of the proposed fuzzy controller is evaluated in terms of auto-tuned control parameters and output responses considered by ITAE index, overshoot, rise time and steady state time.

• 한국항해항만학회지
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• 제44권5호
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• pp.400-406
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• 2020

In this study, we first measured the malmquist productivity index by DEA among the Korean public firms. Second, there are 12 public corporations whose productivity (MPI) has decreased compared to 2014. This is mainly because of a decrease in productivity, as well as a decrease in the technical efficiency change index (TECI), impacted by the internal environment, and the increase in productivity because of an increase in the technology change index (TCI) impacted by the external environment. Finally, the analysis of the impact on the management assessment scores showed that the productivity (MPI), scale efficiency (CRS), size of sales, operating profitability, and total capital investment efficiency are significantly related (+), except for the asset turnover, which is a static financial ratio. Meanwhile, the management evaluation scores between the high-productivity public corporations and low-performing public corporations were significantly discriminating. Thus, it is confirmed that the nation's state-run companies must manage their MPIs in a time series to score high in management evaluation.

• 한국의류학회지
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• 제21권7호
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• pp.1139-1152
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• 1997

Clothing consumption expenditure (UX) data of Korean consumers during the period of 1965 to 1993 were analyzed by time series analysis technique. According to the results of regression analysis, current income and UX of the year before showed most significant influences on the current UX. This means that the absolute and permanent income hypotheses can be accepted in case of clothing expenditures. However the effect of income decreased as the economy developed. The relative price of clothing had weak or no influence on clothing expenditures. It was also found out that CSX of the year before, the change of income, relative price of clothing ware the factors that affected clothing expenditures. From the estimation of Houthakker-Taylor state adjustment model, a negative stock coefficient was obtained. That is, clothing is subject to an inventor effect and Korean consumers regard clothing as one of the durable goods. To define whether clothing is a "luxury" or a "necessity", income and relative price elasticity of clothing expenditures were estimated. Income elasticity of clothing is slightly below 1.0 in case of national aggregate expenditures, and slightly above 1.0 in case of urban consumers' expenditures. Income elasticity has declined over time. Meanwhile the coefficient of price elasticity is not significant, indicating that the relative price of clothing have little connection with clothing expenditure.lothing expenditure.

• 대한치과기공학회지
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• 제41권3호
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• pp.221-232
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• 2019

Purpose: This experiment aims to provide the fundamental resources in developing a programme intended to prevent students from dropping out of their academics by promoting students to develop an optimistic psychological state, through analysis of the factors that influence students' commitment to their major. Methods: A self-administered questionnaire was conducted from $19^{th}$ of November of the year 2018, till $1^{st}$ of December of the same year, with dental technology students located in W city as the subject. 261(93.2%) of the participants' responses were used for the final analysis. Results: A negative association between factors of commitment to major and factors of academic dropout decision were portrayed to be of statistical significance (p<.01), and factors of commitment to major that influence dropping out of their academics were shown to be that of 'autotelic experience' (p<.001) with a negative ( - ) relationship, and 'change in a sense of time' (p<.01) with a positive ( + ) relationship of statistical significance, while the explanatory power of the model was shown to be 33.6%. Conclusion: In order to prevent dental technology students from dropping out of their academics, following their entrance, To achieve this, the department must consider the implementation of, aside from subject matters of the major, other various extra-curricular programmes, and programmes in which the supervisor is consistently providing consultations that are tailored to each individual student.

• 농촌계획
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• 제29권3호
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• pp.15-24
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• 2023

The sense of crisis regarding regional extinction due to low birth rates and an aging population is expanding. Generally, the local extinction index is used to analyze local extinction. However, it is challenging to diagnose the actual situation of village extinction risk in rural areas, even though the regional extinction index can be analyzed in units such as Si-Gun-Gu and Eup-Myeon-Dong. This difficulty arises because the regional extinction index solely relies on natural population growth indicators (elderly population and female population aged 20-39). Therefore, the purpose of this study is to develop a village extinction index that can identify the disappearance of rural villages. Additionally, the aim is to apply the developed indicators to the village (administrative ri) spatial unit. The existing regional extinction index used only mortality-related indicators as factors for natural population decline and fertility-related indicators as factors for natural population growth. However, the developed village extinction index included not only the factors of natural population change but also incorporated social population growth factors and factors related to the pace of village extinction. This is the key difference between the developed village extinction index and the existing regional extinction index. In this study, the indicators of "total population," "number of young women aged 20-44," "number of elderly population aged 70 or older," and "number of incoming population" were selected to develop a village extinction index. The village extinction index was developed by incorporating both natural population growth indicators and social population growth indicators. The developed village extinction index was applied to administrative villages. This research is expected to provide a more accurate understanding of the current state of rural villages facing extinction.

• 한국인구학
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• 제25권1호
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• pp.51-82
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• 2002

본 논문은 60년대 이후 한국 가족의 구조적 변동을 가져온 핵심 요인으로 가족계획사업을 통한 국가의 가족정치(family politics) 과정을 주목하였다. 국가의 용의주도한 기획 아래 가족의 '계획'이 이루어졌으며, '계획합리성(plan rationality)'에 의해 인위적이고 강압적으로 새로운 가족이 만들어진 것이다 가족계획사업의 진행과정에서 국가의 가족정치는 매우 다양하게 나타났다. 사업의 정당성 확보를 위해 근대 가족의 이미지를 동원하는가 하면, 사업의 효율적인 추진을 위해 미시적 감시망 속에 가족을 묶어두기도 했다. 소자녀가족에 대한 경제적 사회적 지원을 통해 근대 핵가족을 유도하기도 했으며, 의료적 기술을 통해 강압적인 구조변동을 이끌기도 했다. 이에 따라 사업 이후 40년 동안 우리 가족은 규모의 축소와 구성의 단순화, 전반적인 근대적 가족행동 및 가치의 증가를 경험하게 되었다. 사업을 통해 국가는 가족을 공적 영역으로 끌어내고. 근대화 기획에 걸맞는 가족 유형과 규범을 만들어 갔다. 그러나 그 과정에서 나타난 가족 문제는 아주 심각하다. 그럼에도 국가는 다시 신자유추의 정치담론을 통해 가족을 국가복지의 대리인이 될 것을 강요하고 있다. '가족을 통한 복지'로 국가복지의 취약성을 대신하려 한다. 가족은 복지의 대상이지 복지의 주체가 아니다. 국가의 가족정치는 바로 이러한 복지 대상으로서 가족을 만들어 가는 노력으로 바뀌어져야 한다.

• 항공우주정책ㆍ법학회지
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• 제14권
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• pp.151-174
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• 2001

Theories of international organization have explained the creation, maintenance, and decline of international organization. However, their explanations on changes of international organization have been much more different one another. For example, the theory of hegemonic stability argues that international organization can be created and maintained only by a hegemonic state and will be declined if the hegemonic state decline. On the other hand, the functional approach believes that the positive functions and effects that international organization provides motivate states to create and maintain the organization, while the game-theoretical approach explains international organization based on cost-benefit calculation of rational states. Thus, the empirical evaluation of the arguments of the theories of international organization and defining the major factors that determine international organization are necessary not only for the development of theories of international organization but also for making desirable policies toward international organization. For the purpose, this paper compares and contrasts the three major theories of international organization and applies the approaches to the case of the International Civil Aviation Organization (ICAO) to test their arguments. Since the ICAO has been rarely examined by the theories of international organization, the case study could be desirable case to evaluate theories of international organization. In this sense, this paper attempts to define the major factors that determine the creation, maintenance, and decline of the ICAO. In particular, since the Korean government has changed its policy for air transport security system recently, it will investigate the role of ICAO on the policy change to define the limits and strength of ICAO. In conclusion, this paper will assess the relative explanatory power of each approach based on the analysis of the creation and changes of ICAO

• 성인간호학회지
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• 제22권1호
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• pp.80-89
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• 2010

Purpose: This paper has attempted to investigate the association between the subclinical thyroid function disorder caused by natural change in thyroid hormones or thyroid remedies and the incidence of CHD. Methods: Data was analyzed of 7,675 women who had undergone health examinations in a hospital in Gyeonggi-do between January 2007 and December 2008. The covariation of the coronary risk factors such as age, BMI, HbA1C, systolic blood pressure, LDL:HDL-cholesterol ratio, CRP, smoking and exercise were analyzed by using logistic regression analysis. Results: A significant increase in serum TSH was observed with higher age (F=26.91, p=.00). In terms of age, the risk of CHD started to gradually increase since the 40s and sharply since the 60s (${\chi}^2$=113.29, p=.00). The serum TSH was the most significant parameter influencing CHD (B=.12, p=.00). The risk of coronary heart disease was 3.12 times higher in the subclinical hypothyroidism group (OR=3.12) while no significant difference was observed in the subclinical hyperthyroidism group. Conclusion: Subclinical hypothyroidism may be an independent risk factors for CHD. A nurse nursing patients with thyroid disorder should be well informed of their state of subclinical thyroid function disorder and make efforts to extend their health expectancy.