• KDI Journal of Economic Policy
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• 제26권1호
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• pp.105-140
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• 2004

Korea is entering the class of aging population nations. This paper investigates the extent demographic factors and the aging population affect the saving rate, using an extended life-cycle/permanent-income hypothesis on saving. The results of the tests with Korean household survey data from 1977 to 2002 reveal that real saving rates increase when the duration of lifetime and per household real disposable income rise, and decrease when the growth rate of income and net worth-to-GDP ratio rises. The growth rate of per household real disposable income has negative effects, suggesting that households calculate their life cycle income in a forward looking manner. The elasticities with respect to a change in the lifetime horizon and the growth rate of per household income are 0.58 and -0.03, respectively. A one percent rise in the net worth to GDP ratio reduces the saving rate by 0.3 percent. A one percent rise in per household income increases it by 0.33 percent. The younger-age and the elder-age dependency ratios have insignificant effects on the household saving rate behavior. When Korean life expectancy rises, the private saving rate declines modestly and the government saving rate declines substantially. The economy's real net saving rate declines from 33 percent in 2002 to 30 percent by the year 2030.

• Smart Structures and Systems
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• 제5권1호
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• pp.95-117
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• 2009

In this paper, the time series based damage detection algorithms developed by Nair, et al. (2006) and Nair and Kiremidjian (2007) are applied to the benchmark experimental data from the National Center for Research on Earthquake Engineering (NCREE) in Taipei, Taiwan. Both acceleration and strain data are analyzed. The data are modeled as autoregressive (AR) processes, and damage sensitive features (DSF) and feature vectors are defined in terms of the first three AR coefficients. In the first algorithm developed by Nair, et al. (2006), hypothesis tests using the t-statistic are applied to evaluate the damaged state. A damage measure (DM) is defined to measure the damage extent. The results show that the DSF's from the acceleration data can detect damage while the DSF from the strain data can be used to localize the damage. The DM can be used for damage quantification. In the second algorithm developed by Nair and Kiremidjian (2007) a Gaussian Mixture Model (GMM) is used to model the feature vector, and the Mahalanobis distance is defined to measure damage extent. Additional distance measures are defined and applied in this paper to quantify damage. The results show that damage measures can be used to detect, quantify, and localize the damage for the high intensity and the bidirectional loading cases.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3247-3255
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• 2021

As Probabilistic Safety Assessments (PSAs) are thoroughly conducted for the Site Operating States (SOSs) for a single unit, multi-unit Probabilistic Safety Assessments (MUPSAs) are ongoing worldwide to address new technical challenges or issues. In South Korea, the determination of the site operating states for a single site requires a logical approach with reasonable assumptions due to the fact that there are 4-8 operating units for each site. This paper suggests a simulation model that gives a reasonable expectation of the site operation states using the Monte-Carlo method as a stochastic approach and deterministic aspects such as operational policies. Statistical hypothesis tests were conducted so that the reliance of the simulation results can be guaranteed. In this study, 7 units of the Kori site were analysed as a case study. The result shows that the fraction of full power for all 7 units is nearly 0.45. For situations when more than two units are not in operation, the highest fraction combination was obtained for Plant Operation State (POS) 8, which is the stage of inspection and repairment. By entering various site operation scenarios, the simulation model can be used for the analysis of other site operation states.

• 재무관리연구
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• 제24권1호
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• pp.59-83
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• 2007

본 연구에서는 자사주매입이 처음으로 허용된 1994년 5월 1일부터 2005년 12월 31일까지 자사주매입기업을 대상으로 잉여현금흐름가설을 검정하였으며, 그 결과는 다음과 같다. 자사주매입기업은 통제기업보다 수익성이 증가하지 않았으며, 성장기회 감소에 따라 투자지출을 감소시키고 자사주매입을 통해 현금보유도 감소시키는 것으로 나타났다. 또한 자사주매입 기업은 체계적 위험과 투자지출의 감소에 따라 자본비용이 감소하였다. 그리고 자사주매입기업은 수익성이 증가하지 않는데도 불구하고 자본비용이 감소하기 때문에 주가는 유의한 양(+)의 반응을 나타냈다. 이러한 연구결과를 종합하면, 선행연구에서 검정된 저평가에 따른 정보신호가설과 경영자 기회주의 가설에 이어 잉여현금흐름가설도 한국증권시장에서 부분적으로 지지된다고 할 수 있다. 따라서 기업이 성숙기에 이르러 수익성 감소, 투자지출과 현금보유 감소, 체계적 위험과 자본비용 감소를 겪고 있는 기업은 잉여현금흐름을 줄이기 위해 자사주매입을 하는 것이 유리할 수 있다.

• 한국정보처리학회논문지
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• 제7권8호
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• pp.2555-2564
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• 2000

본 논문에서는 새로운 무관리형 화상분할 알고리즘이 제안된다. 제안된 알고리즘은 화상에 내재되어 있는 구조 정보를 모델링하기 위하여 마르코프 랜덤필드의 특성을 이용하고 있다. 텍스쳐 화상은 정상상태의 가우스 마르코프 랜덤필드가 2차원의 격자구조 위에 실현된 상태로 간주되었으며 2차의 비순차근방을 갖는 조건부 자기회귀함수를 이용하여 모델링 되었다. 화상의 경계면 감출을 위하여 마스크로 선택된 두 영역에 대한 가설검정이 수행된다. 이 방법은 선택된 두 영역이 같은 종류의 텍스쳐라고 가정을 한 후 조건부 자기회귀모델의 매개변수를 최소평균제곱오차 측면에서 추정한다. 가설이 거절되면 두 영역의 상이함을 측정한 그 값이 선택된 영역에 누적된다. 이와 겉은 방법을 통하여 잠재적인 경제지도가 얻어지며, 이것을 통하여 여러 종류의 텍스쳐 화상의 분할이 미세오류경계 없이 이루어지게 된다. 제안된 알고리즘의 성능은 인공화상 뿐만 아니라 실제의 자연화상을 이용한 실험을 통하여 입증되었으며 일체의 사전정보 없이도 만족할 만한 결과를 보여 주었다.

• 대한조선학회논문집
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• 제53권2호
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• pp.127-134
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• 2016

This paper presents practical issues for test and evaluation(T&E) methods to develop defense systems. Our argument is motivated by several domestic defense cases and the cases lead us to discuss two main factors for reliable defense systems development: 1) statistical approaches and 2) technical schemes. Specifically, statistical approaches enable to provide credible interpretations about T&E results in the decision-making process. With practical T&E results of the “Red Shark” torpedo, we performed statistical hypothesis tests and suggest a minimum sample size to accept the hypothesis. Next, technical schemes have more direct effects on improving reliability of developed defense systems and we shortly introduce tools development for systems verification that is required to integrate several sub-systems, e.g., combat, sensor, weapon, and communication systems, within a defense system. We additionally summary some domain cases using modeling and simulation techniques for successful T&E. In closing, we expect that the paper shows empirical investigation and lessons learned with these two practical issues, which provides a guide those who desire to make decisions about reliable defense systems development.

• 아태비즈니스연구
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• 제11권4호
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• pp.65-81
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• 2020

Purpose - This research aims to investigate how consumers' eco-friendly product choice ratio changes as the benefits of eco-friendly products are framed as (1) non-monetary benefits, (2) monetary gain integrated with the loss or (3) monetary gain segregated from the loss. Design/methodology/approach - A mixed-design, scenario-based choice experiment was conducted. A series of chi-square tests and residual analyses were conducted to analyze the data. Findings - When the monetary gain was larger or slightly smaller than the loss, the participants' eco-friendly product choice ratio was higher when the monetary gain was integrated with the loss than those in the other two conditions. When the monetary gain was significantly smaller than the loss, the participants' eco-friendly product choice ratio was lower when the monetary gain was integrated with the loss than those in the other conditions. The ratio did not differ between the latter two conditions. Research implications or Originality - This research shows that marketers should frame the benefits of eco-friendly products and their costs in different manners depending on the relative magnitudes of them. This research also complements the existing literature by comparing the effectiveness of non-monetary framing of eco-friendly product benefits with that of monetary framing following hedonic editing hypothesis.

• 대한간호학회지
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• 제22권4호
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• pp.620-635
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• 1992

This study identified correlations between perceived family support and hopelessness in patients admitted to Neuro - surgical Intensive Care Units. The purpose was to enhance theoretical understanding of the relationships of these two variables. The subjects of this study were 51 patients admitted to N-lCU, at three general hospitals in Seoul. Data were collected by researcher in structured interviews from Aug. 12 to Oct. 13, 1992. The research tools were parts of the Moos Family Environment Scale and the Beck Hopelessness Scale. The general characteristic data were analyzed for frequency and percentage ; the hypothesis was tested by the pearson product Moment Correlation Coefficient. After normality tests by using Kolmogorov - Sminorvtest, and T- test, ANOVA and Mann-Whitney U test, Kruskal -Wallis test were used on the Family Support and the Hopelessness about general charcteristics. The results of the above analysis were as follows 1) The average family support score for the group was 63.61 (tool average 51) and item average was 3.74 (tool item average 3) : the family support score of this sample was higher than average. The average family cohesion score of family support was 35.25 (tool average 27) and item average was 3.91 (tool item average 3). The average family expression score of family support was 28.35 (tool average 24) and item average was 3.57 (tool average 3). In this sample, perceived family expression was lower than family cohesion. 2) The average hopelessness score was 45.88 (tool average 60) and item average was 2.29 (tool item average 3) : the hopelessness score of this sample was low in comparison to the average. 3) The hypothesis in this study was supported. The main hypothesis that the higher the perceived family support level, the lower the level Of the hopelessness, was Supported (r＝-.3869 p＝.003). The sub-hypothesis that the higher the perceived family cohesion level, the lower the level of hopelessness, was supported(r＝-.3688 p＝.004). The sub-hypothesis that the higher the perceived family expression level, the lower the level of hopelessness, was supported (r＝-.3068 p＝.014). 4) General characteristics of the objects related to family support were ‘economic status’(p＝.025) and ‘helping person’(P＝.044) : the higher the economic status, the greater the family support. When the patient identified the helping person as a spouse, family support was rated more highly. The only general characteristic related to family cohesion was ‘helping person’(p＝.041). No general characteristics were related to family expression. 5) The one general characteristic related to hopelessness was ‘education’(p＝.002) : the higher their education, the lower their hopelessness. For these ICU patients, were related perceived family support and hopelessness, and family expression level was low in comparison to family cohesion level. The perceived family support of these seriously ill patients in situational crisis may have influenced the patient's emotional reaction of hopelessness. This study concluded that nurses in the ICU confirm the family support of the patient, and involve the family as the most intimate support systems in the care of the patient to help reduce the patient's hopelessness.

• 대한교통학회지
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• 제25권6호
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• pp.55-63
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• 2007

본 연구는 고속도로 교차점의 유형과 교통사고와의 관계를 다루고 있다. 본 연구의 목적은 교통사고가 교차점의 유형과 기하구조 설계요소에 따라 다르게 나타날 수 있다는 가설을 검증하는데 있다. 연구의 주요 결과는 다음과 같다. 첫째, JCT와 IC 그리고 트럼펫 IC와 기타 유형의 IC 간의 사고 비교는 의미를 갖지 못하지만, 트럼펫 IC의 네 가지 유형별 차이는 의미가 있는 것으로 분석되었다. 즉 BO 형태의 트럼펫 IC는 타 형태의 트럼펫 IC보다 월등히 많은 교통사고를 나타내고 있다. 둘째, 가설검정을 통해 본선과의 교차각은 가능한 직각으로 설계하고 연결로 교통량이 많지 않은 한 1차로로 설계하는 것이 바람직하다고 나타났다. 이러한 연구결과는 장래 고속도로의 설계에서 보다 안전한 인터체인지의 유형결정과 기하구조 설계에 반영될 수 있는 방향을 제시할 수 있을 것으로 기대된다. 도로 안전 측면에서 가능한 BO 형태의 인터체인지는 도입하지 않고, 교차각을 $90^{\circ}$가 되도록 설계하되, 인터체인지의 경우 연결로 교통량이 아주 많지 않다면 1차로로 설계하는 것이 바람직한 것으로 판단된다.

• 한국과학교육학회지
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• 제17권2호
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• pp.201-207
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• 1997

This study was performed to survey the achievements in problem solving by the inquiring experiment, which was done by the superior group in the traditional cocepts-centered written tests. The purpose of this study was to identify characteristics of inquiring experimental assessment by analyzing differences between concepts-centered written and inquiring experimental tests. The subjects of this study was 211 applicants. They are the superior group of the 9th grade students, and score in the top 1% of total achievements percentage in school. They also have passed the primary entrance examination. The inquiring experimental test was developed according to the curriculum in school, and is composed of 5 subcategories: problem-perception and formulating hypothesis, designing an experiment, carring out an experiment, recording data and drawing conculsion, and generalizing conculsions and communicaton. The checklists of each subcategory were made and testing methods were divided into observation and report. The major results of this study are as follows: 1. The achievements in each subcategory of inquiring experimental performance were very low in the superior group who took the concepts-centered written tests. 2. The results of factor and correlation analyses in this study confirmed the abilities measured by inquiring experimental assessment differed from abilities measured by existing tests. These results indicated that even students who achieved high in scientific knowledge, these abilities were not automatically transformed inquiry process which many other abilities were integrated into. Therefore, problem solving ability requires integrated abilities which are fostered by inquiring experimental tasks. This suggests that new instrument for assessment must be developed to measure integrating ability especially where scientifically gifted students are selected, or where entrance examinations to the science schools are administered.