• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.159-160
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• 2018

The domestic construction industry is changing its preference for demand and supply along with urbanization and economic development. Accordingly, initial risk assessments is more important than before. Currently, the research related to risk analysis except for apartment studies is insufficient. Therefore, the objective is to suggest a basic study on financial analysis model development by applying optimization method in residential officetel. To achieve the objective. first, the previous studies are investigated. Second, the causal loop diagram is structured based on the collected data. Third, the financial model is developed by using optimization method. In the future, the proposed model can be helpful whether or not conduct execution of an officetel development project to the decision makers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.926-938
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• 1996

In this paper, we proposed a new multicast algorithm which is efficiently applicable to overlapped process group environments where one process may be involved in several process groups. Unlike the esisting algorithms, the proposed one provides an efficient group communication mechanism by generating the processgroup information in two-level tree. Using this algorithm, we improved the shortcoming of the existing algorithms by reducing the overhead in passing through unnecessary processes for message ordering. We have provided the causal ordering method as well as the total ordering method in group communication environments. As a result, we allow one process to deliver message to other processes with a short delay time, and reduced the overhead required for the message ordering. Also, we logically proved the proposed causal ordering method, and compared the performance of the proposed algorithm with ones of other existing algorithms by computer simulation.

• Communications for Statistical Applications and Methods
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• v.27 no.6
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• pp.675-688
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• 2020

In survival analysis of observational data, the inverse probability weighting method and the Cox proportional hazards model are widely used when estimating the causal effects of multiple-valued treatment. In this paper, the two kinds of weights have been examined in the inverse probability weighting method. We explain the reason why the stabilized weight is more appropriate when an inverse probability weighting method using the generalized propensity score is applied. We also emphasize that a marginal hazard ratio and the conditional hazard ratio should be distinguished when defining the hazard ratio as a treatment effect under the Cox proportional hazards model. A simulation study based on real data is conducted to provide concrete numerical evidence.

• 한국체육학회지인문사회과학편
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• v.54 no.5
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• pp.233-250
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• 2015

In this study, changes and emotions that result from doing yoga and the influence of yoga on daily lives were investigated by using causal network. This information was gathered from interviews and outlined in a diagram form. By checking the daily participation records of 77 participants who took a yoga class as part of the cultural studies curriculum at H University, general factors related to change were extracted and then 7 participants were chosen for in-depth interviews. In the interviews, the changes experienced from doing yoga and the emotions caused by the change and the influence this change had on daily lives were documented and the collected results were displayed in a diagram using causal network according to the flow of questionnaire. As a result, the changes experienced through doing yoga were divided in 4 categories: physical function, emotional, cognitive and physiological changes. Each change and emotion caused by the change were shown to have an influence on daily lives. Through schematized causal network for each change, the changes and emotions which the participants experienced and the influence of yoga on daily lives could be checked. Based on the study results, the effect of yoga, the need for various approaches to examine the effect exercise has on emotions and the applicability of causal network that can be employed as a creative and effective quantitative data analysis method were discussed.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.120-133
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• 2000

Major obstruction of using formal methods for hybrid real-time systems in industry is the difficulty that engineers have in understanding and applying the quantitative methods in an abstract requirements phase. While formal methods technology in safety-critical systems can help increase confidence of software, difficulty and complexity in using them can cause another hazard. In order to overcome this obstruction, we propose a framework for qualitative requirements engineering of the hybrid real-time systems. It consists of a qualitative method for requirements specification, called QFM (Qualitative Formal Method), and a safety analysis method for the requirements based on a causality information, called CRSA (Causal Requirements Safety Analysis). QFM emphasizes the idea of a causal and qualitative reasoning in formal methods to reduce the cognitive burden of designers when specifying and validating the software requirements of hybrid safety systems. CRSA can evaluate the logical contribution of the software elements to the physical hazard of systems by utilizing the causality information that is kept during specification by QFM. Using the Shutdown System 2 of Wolsong nuclear power plants as a realistic example, we demonstrate the effectiveness of our approach.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.6
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• pp.79-97
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• 2003

The purpose of this paper is to analyze a causal model determining social carrying capacity(SCC) in natural parks, to answer the research question: What is the mechanism for determining SCC in natural parks (NP)\ulcorner After reviewing the literature on SCC and recreation activities in Korean natural parks, we constructed a conceptual framework and formulated the hypothesis of this research. We obtained data through a questionnaire which surveyed 487 visitors at 6 of the 73 NP in Korea during 2001, based on a stratified sampling method. We analyzed the data using descriptive statistical methods, the mean difference test, Pearson's correlation analysis, and path analysis method. We found that 1) The direct effect of resources, activity space(AS), visitor's expectation(VE), encounter, crowding, damage of resources(DR), maintenance condition of resources and facility(MCRF) to SCC are 3.45, 3.62, 2.75, 2.72, 1.32, and 4.77 times more important than that of crowding, respectively, while the indirect effect of resources, AS, VE, encounter, and DR to SCC is 13.03, 11.19, 3.34, 1.3, 2.05, 1.10, 0.05 and 2.30 times more important then that of crowding, respectively, 2) Causal effects of resources, facility, AS, VE, number of visitors(NV), encounter, crowding, VM, DR, and MCRF to SCC turned out to have 0.3523, 0.3321, 0.1751, 0.1465, 0.0307, 0.0762, 0.0604, -0.0510, -0.1177 and 0.2165, respectively, and 3) The causal effect of activity base(AB) and activity atmosphere(AA) to SCC turned out to have 2.57 and 1.1 times higher than that of MCRF, respectively. The research results suggest that 1) this conceptual framework is highly useful for the development of substantive theory and methodology; 2) management issues of AA and MCRF turned out to have 0.81 times in SCC that of AB, i.e, SCC can be significantly improved from control of AA and MCRF; and 3) supply of excellent resources and convenient facilities is needed to increase social carrying capacity. It is recommended that more empirical studies be performed in the future according to the season, visitor characteristics, and AS by NP.

• Journal of the Korean Geotechnical Society
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• v.28 no.10
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• pp.89-96
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• 2012

In this study landslide causal factors which are considered to have the same effect in assessment techniques are categorized and their impact on landslides is analyzed to acquire reasonable weighting factors in the landslide hazard. Results are compared to those of the Assessment Chart developed by National Institute for Disaster Prevention (NIDP) and the adequacy and proper portion for landslide causal factors are considered. The Artificial Neural Network (ANN) method applied to 28 landslide areas is incorporated to evaluate the reasonable rating. Results show that the following items in the Chart are necessary to modify their portions in order to implement the precise assessment results: 1) Estimated damage; 2) Tension crack; 3) Existence of valley.

• The Journal of the Acoustical Society of Korea
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• v.10 no.2
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• pp.23-28
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• 1991

This paper is a study on isolated word recognition by independent speaker, we propose DTW speech recognition system by modified dynamic averaging method as reference pattern. 57 city names are selected as recognition vocabulary and 2th LPC cepstrum coefficients are used as the feature parameter. In this paper, besides recognition experiment using modified dynamic averaging method as reference pattern, we perform recognition experiments using causal method, dynamic averaging method, linear averaging method and clustering method with the same data in the same conditions for comparison with it. Through the experiment result, it is proved that recogntion rate by DTW using modified dynamic averaging method is the best as 97.6 percent.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.143-152
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• 2008

Road freight transport industry in Korea contains many and complicate problems such as over supply of the vehicle caused by rapid policy changes, illegal multilevel transactions, poor truck drivers working environment, lack of road freight transport related statistics and so on. Korean government has developed various logistics industrial policy trying to solve these problems in various ways. However the relationship among the problems and action plans has been more and more entangled since the part of suggested policies have made another perverted problems. These complex structure of the toad freight transport industry in Korea makes difficult to identify and to solve the problems. Causal map method helps to give a clean picture to understand the complex industry at a fiance. This study contributes for visualization of the causal relationships among the existing problems and related policy issues in the road freight transport industry in Korea by causal map. This study could be helpful to develop the actual road freight transport industrial policies including the illogical multilevel and unfair transaction in Korea.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.361-369
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• 2017

This paper analyzes the causal relationship between dollar exchange rate and international oil price. Although large literature on the relationship has accumulated, results are not unique but diversified. Based on the idea that such diversified results may be due to different causality at different economic status, we considers an approach to test the causal relationship at each quantile. This approach is different from the mean causality analysis widely employed by the existing literature of the causal relationship. In this paper, monthly data from May 1987 to 2013 is used for the causal analysis in which Brent oil price and Major Currencies Dollar Index (MCDI) are considered. The test method is the nonparametric test for causality in quantile suggested by Jeong et al. (2012). The results show that although dollar exchange rate causes oil price in mean, the causal relationship does not exist at most quantiles.