• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 1999년도 춘계공동학술대회-지식경영과 지식공학
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support for multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To data, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• Journal of Preventive Medicine and Public Health
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• 제50권1호
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• pp.1-9
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• 2017

Objectives: By the end of the 2000s, the economic situation in many European countries started to deteriorate, generating financial uncertainty, social insecurity and worse health status. The aim of the present study was to investigate how the recent financial crisis has affected the lifestyle health determinants and behaviours of older adults living in the Mediterranean islands. Methods: From 2005 to 2015, a population-based, multi-stage convenience sampling method was used to voluntarily enrol 2749 older adults (50% men) from 20 Mediterranean islands and the rural area of the Mani peninsula. Lifestyle status was evaluated as the cumulative score of four components (range, 0 to 6), that is, smoking habits, diet quality (MedDietScore), depression status (Geriatric Depression Scale) and physical activity. Results: Older Mediterranean people enrolled in the study from 2009 onwards showed social isolation and increased smoking, were more prone to depressive symptoms, and adopted less healthy dietary habits, as compared to their counterparts participating earlier in the study (p<0.05), irrespective of age, gender, several clinical characteristics, or socioeconomic status of the participants (an almost 50% adjusted increase in the lifestyle score from before 2009 to after 2009, p<0.001). Conclusions: A shift towards less healthy behaviours was noticeable after the economic crisis had commenced. Public health interventions should focus on older adults, particularly of lower socioeconomic levels, in order to effectively reduce the burden of cardiometabolic disease at the population level.

• 한국병원경영학회지
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• 제21권1호
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• pp.1-13
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• 2016

As the importance of strengthening the competency of managers who are in charge of cash collection and disbursement, and preparing for financial statements becomes more visible, this study examined the competency of middle-level managers of accounting department in general hospitals in Korea. Based on the literature, competency was measured by seven components: achievement and action, service, influence, management, cognition, individual effectiveness, and change management. Survey questionnaires included the respondents' perceived importance and performance of each of the seven components of competency. A total of 84 managers from 29 general hospitals responded to the survey between October 2015 and November 2015. Descriptive statistics, mean comparison (t-tests and ANOVAs), and multiple linear regression were conducted. The results of this study are as follows. Overall perceived importance of the competency was 4.16, while the performance was 3.87, and thus, the difference was 0.29. Among the seven components of the competency, cognition and change management had higher scores in terms of difference between the importance and performance. The regression analyses found that female managers had higher perceived importance and performance of competencies in achievement and action, and influence compared to male counterparts. In addition, participants in this study responded that main reasons for the gap between the perceived importance and performance are low compensation, lack of support, lack of knowledge, insufficient technical experience, excessive workload, and regulations. The results of this study can be used when designing capacity building training opportunities for the hospital accounting department. Also, the managers may evaluate themselves and look at the areas where they can narrow the gap between the perceived importance and performance of the competency that is required for today's leading managers.

• Steel and Composite Structures
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• 제22권3호
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• pp.537-565
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• 2016

Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.

• 상하수도학회지
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• 제35권1호
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• pp.53-61
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• 2021

The quantified analysis of damages to wastewater treatment plants by natural disasters is essential to maintain the stability of wastewater treatment systems. However, studies on the quantified analysis of natural disaster effects on wastewater treatment systems are very rare. In this study, a total disaster index (DI) was developed to quantify the various damages to wastewater treatment systems from natural disasters using two statistical methods (i.e., AHP: analytic hierarchy process and PCA: principal component analysis). Typhoons, heavy rain, and earthquakes are considered as three major natural disasters for the development of the DI. A total of 15 input variables from public open-source data (e.g., statistical yearbook of wastewater treatment system, meteorological data and financial status in local governments) were used for the development of a DI for 199 wastewater treatment plants in Korea. The total DI was calculated from the weighted sum of the disaster indices of the three natural disasters (i.e., TI for typhoon, RI for heavy rain, and EI for earthquake). The three disaster indices of each natural disaster were determined from four components, such as possibility of occurrence and expected damages. The relative weights of the four components to calculate the disaster indices (TI, RI and EI) for each of the three natural disasters were also determined from AHP. PCA was used to determine the relative weights of the input variables to calculate the four components. The relative weights of TI, RI and EI to calculate total DI were determined as 0.547, 0.306, and 0.147 respectively.

• 산업융합연구
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• 제20권2호
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• pp.51-59
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• 2022

본 연구에서는 초등교사의 노벨 엔지니어링 수업에 대한 경험을 현상학적 질적 연구 방법으로 분석하였다. 본 연구의 목적은 초등교사가 어떤 이유로 노벨 엔지니어링에 관심을 가졌는지를 알아보고, 이 수업이 가지는 장단점들과 융합 수업 모형으로서의 확산 가능성을 알아보는 것이다. 이를 위해서 연구 참여자인 4명의 초등교사는 2021년도 2학기에 교육과정 재구성을 통하여 노벨 엔지니어링 기반 주제 중심 생태감수성 수업을 진행하였다. 이후 본 연구자는 4명의 교사를 대상으로 면담을 실시하였다. 면담 분석 결과, 13개의 하위 구성 요소와 4개의 구성요소가 도출되었다. 도출된 구성요소는 실수로부터 배움, 수업 연구에 대한 중요성 인식, 창작물 제작 과정을 통한 아이들의 창의성 발현, 노벨 엔지니어링과 기존 교과목과의 높은 연계 가능성이다. 이 연구의 시사점은 교사의 자율적인 수업 연구를 위한 교육현장의 분위기 확산, 교사의 교과와 실제를 융합하는 비교과 교육과정 개발 역량 함양, 그리고 노벨 엔지니어링과 같은 실용적인 수업 모형 개발에 관한 연수 프로그램 확대이다.

• 정보학연구
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• 제1권2호
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• pp.209-227
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• 1998

본 연구는 회계이익을 구성요소별로 분리시켜 회계이익과 주가수익률간의 관계에서 영업현금흐름, 재량적 발생액, 비재량적 발생액, 및 비재량적 이익이 회계이익에 대해 추가적 정보효과를 제공하는지 여부를 한국자본시장의 자료를 이용하여 실증적으로 검증한다. 이를 위해 회계이익을 영업현금흐름과 총발생액으로 구분하고, 다시 총발생액을 재량적 발생액과 비재량적 발생액으로 분리시켜, 종속변수를 초과수익률로 하고 독립변수에 각 회계이익의 구성요소들을 포함시키는 회귀분석방법으로 검증하였다. 표본기업은 1984년부터 1995년까지 연속된 자료를 이용할 수 있는 158개 기업을 대상으로 하였고, 1984년부터 1993년(10년간 통합된 1,580개 자료)까지는 비재량적 발생액의 추정기간으로 삼아 Jones모형(1991)을 이용한 산업-연도별 횡단면 회귀분석모형으로 추정한 다음에 1994, 1993년(2년간 통합된 316개 자료)을 검증기간으로 하여 총 발생액을 재량적 발생액과 비재량적 발생액으로 분리시키는 방법을 사용하였다. 연구곁과에 의하면, 회계이익의 구성요소들을 독립변수로 하고 주가수익률을 종속변수로 하는 다중회귀분석에서는 회계이익에 대해 영업현금흐름과 재량적 발생액은 추가적 정보가치가 있는 것으로 나타났다. 이는 재량적 발생액이 기업성과측정가설과 일치하는 것으로 해석 할 수 있다. 또한 회계이익에 대해 비재량적 이익과 재량적 발생액도 추가적 정보가치가 있는 것으로 나타났다. 그리고 추가분석결과에서는 비재량적 발생액의 절대값의 크기가 큰 집단에서 유의한 양의 더미변수가 검증되었는데, 이는 비재량적 발생액의 절대적 크기가 클수록, 회계이익과 영업현금흐름에 대해서 순기능적인 추가적 정보력을 제공하는 것으로 여겨진다.

• 농업과학연구
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• 제23권1호
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• pp.159-176
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• 1996

This study is aimed at reviewing the methods of joint cost allocation and allocating the joint cost of estuary dam with specially repect to Kumgang Large-scale Agricultural Comprehensive Development Project. Apart from the water resource development project propelled by Water Resource Development Corporation in connection with Law of Multipurpose Dam Development, the Largescale Comprehensive Agricultural Development Projects couldn't ins-titutionally be carried out cost allocation of common facilities, even though it were concerned with irrigation, municipal and industrical water supply, flood control, sightseeing and industrial zone development components. To decrease farmer's burden of the project costs and, operation and maintenance costs, the joint costs of common facilities like estuary dam included in agricultural development projects have to be allocated by suitable method as alternative cost-remaining benefit method and the analytical activity should be supported by revising the concerned laws as Rural Development and Promotion and, Rural Rearrangement conpatible with the law for multipurpose dam development. Kumgang Agricultural Comprehensive Development Project was selected as a case study for the estimation of socio-economic benefits by project components and joint cost allocation of the estuary dam. The main results of the study are as follows; Joint cost allocation and unit charges by components 1. The project area will be 25,554ha with total project cost of 624,860 million won including the estuary dam cost of 120,843 million won. The project costs were ex-pressed by 1994 constant price. 2. Total quantity of water was estimated 365 million tons which were consisted of 245 million tons for irrigation, 73 million tons for municipal water and 47 million tons for industrial water. 3. The rates of joint cost allocation were amounted to 34.2% for agriculture, 2.5% for sightseeing, 45.7% for transportation, 11.8% for M & I water supply and 5.8% for flood control respectively. 4. The unit financial charges by project components were estimated at 7.88 won per ton for irrigation, 16.11won for M & I water, 1,686won per vehicle one pass, 977won per Pyeong according to the capital recovery method. The financial charges using straitline method for depreciation were estimated at 7.88won per ton for irrigation, 9.12won per ton for M & I water, 624won per vehicle one pass for transportation and 331won per Pyeong for sightseeing area. 5. The unit economic charges by project components were estimated at 21.1 won per ton for irrigation, 15.2won for M & I water, 977won per vehicle one pass, 977won per Pyeong according to the capital recovery method. The economic charges using straitline method for depreciation were estimated at 11.72won per ton for irrigation, 8.61won per ton for M & I water, 331won per vehicle one pass for transportation. Policy recommendation 1. The unit operation and maintenance costs for irrigation water in the paddy field couldn't be imposed as the water resource cost untreated. 2. The dam costs including investment cost and O & M cost, as a joint cost, had to be allocated by each benefited components as transportation, M & I water supply, flood control, irrigation and drainage, and sightseeing. But the agricultural comprehensive project have been dealt as an irrigation project without any appraisal socio-economic benefits and any allocating the joint cost of estuary dam. 3. All the associated project benefits and costs must be evaluated based on accounting principle and rent recovery rate of the project costs and O & M costs should be regulated by the laws concerned. 4. The rural development and promotion law and rural rearrangement law have to be revised comprising joint cost allocation considering free rider problems. 5. The government subsidy for the agricultural base development project has to be covered all the project costs. In case of common facilities representing joint cost allocation problems, all the allocated casts for other purposes like transportation and M & I water supply etc. should be recovered for formation in investment fund for agricultural base development and to procure O & M costs for irrigation facilities.

• Management Science and Financial Engineering
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• 제14권2호
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• pp.105-118
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• 2008

There are many debates on the topic of the relationship between oil prices and economic growth. Through the repeated processes of conformations and contractions on the subject, two main issues are developed; one is how to define and drive oil shocks from oil prices, and the other is how to specify an econometric model to reflect the asymmetric relations between oil prices and output growth. The study, thus, introduces the unobserved component model to pick up the oil shocks and a first-order Markov switching model to reflect the asymmetric features. We finally employ unique oil shock variables from the stochastic trend components of oil prices and adapt four lags of the mean growth Markov Switching model. The results indicate that oil shocks exert more impact to recessionary state than expansionary state and the supply-side oil shocks are more persistent and significant than the demand-side shocks.

• Management Science and Financial Engineering
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• 제12권1호
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• pp.95-112
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• 2006

Disassembly scheduling is the problem of determining the quantity and timing of disassembling used or end-of-life products while satisfying the demand of their parts and/or components over a planning horizon. The case of assembly product structure is considered while the resource capacity constraints are explicitly considered. A cost-based objective is considered that minimizes the sum of disassembly operation and inventory holding costs. The problem is formulated as an integer programming model, and a two-stage heuristic with construction and improvement algorithms is suggested in this paper. To test the performance of the heuristic, computational experiments are done on randomly generated problems, and the results show that the heuristic gives near optimal solutions within a very short amount of computation time.