• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.305-316
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• 2009

In this study, we suggest an empirical forecast of CIR (Corotating Interaction Regions) and geomagnetic storm based on the information of coronal holes (CH). For this we used CH data obtained from He I $10830{\AA}$ maps at National Solar Observatory-Kitt Peak from January 1996 to November 2003 and the CIR and storm data that Choi et al. (2009) identified. Considering the relationship among coronal holes, CIRs, and geomagnetic storms (Choi et al. 2009), we propose the criteria for geoeffective coronal holes; the center of CH is located between $N40^{\circ}$ and $S40^{\circ}$ and between $E40^{\circ}$ and $W20^{\circ}$, and its area in percentage of solar hemispheric area is larger than the following areas: (1) case 1: 0.36%, (2) case 2: 0.66%, (3) case 3: 0.36% for 1996-2000, and 0.66% for 2001-2003. Then we present contingency tables between prediction and observation for three cases and their dependence on solar cycle phase. From the contingency tables, we determined several statistical parameters for forecast evaluation such as PODy (the probability of detection yes), FAR (the false alarm ratio), Bias (the ratio of "yes" predictions to "yes" observations) and CSI (critical success index). Considering the importance of PODy and CSI, we found that the best criterion is case 3; CH-CIR: PODy=0.77, FAR=0.66, Bias=2.28, CSI=0.30. CH-storm: PODy=0.81, FAR=0.84, Bias=5.00, CSI=0.16. It is also found that the parameters after the solar maximum are much better than those before the solar maximum. Our results show that the forecasting of CIR based on coronal hole information is meaningful but the forecast of goemagnetic storm is challenging.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.23-45
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• 2020

Big data is creating in a wide variety of fields such as medical care, manufacturing, logistics, sales site, SNS, and the dataset characteristics are also diverse. In order to secure the competitiveness of companies, it is necessary to improve decision-making capacity using a classification algorithm. However, most of them do not have sufficient knowledge on what kind of classification algorithm is appropriate for a specific problem area. In other words, determining which classification algorithm is appropriate depending on the characteristics of the dataset was has been a task that required expertise and effort. This is because the relationship between the characteristics of datasets (called meta-features) and the performance of classification algorithms has not been fully understood. Moreover, there has been little research on meta-features reflecting the characteristics of multi-class. Therefore, the purpose of this study is to empirically analyze whether meta-features of multi-class datasets have a significant effect on the performance of classification algorithms. In this study, meta-features of multi-class datasets were identified into two factors, (the data structure and the data complexity,) and seven representative meta-features were selected. Among those, we included the Herfindahl-Hirschman Index (HHI), originally a market concentration measurement index, in the meta-features to replace IR(Imbalanced Ratio). Also, we developed a new index called Reverse ReLU Silhouette Score into the meta-feature set. Among the UCI Machine Learning Repository data, six representative datasets (Balance Scale, PageBlocks, Car Evaluation, User Knowledge-Modeling, Wine Quality(red), Contraceptive Method Choice) were selected. The class of each dataset was classified by using the classification algorithms (KNN, Logistic Regression, Nave Bayes, Random Forest, and SVM) selected in the study. For each dataset, we applied 10-fold cross validation method. 10% to 100% oversampling method is applied for each fold and meta-features of the dataset is measured. The meta-features selected are HHI, Number of Classes, Number of Features, Entropy, Reverse ReLU Silhouette Score, Nonlinearity of Linear Classifier, Hub Score. F1-score was selected as the dependent variable. As a result, the results of this study showed that the six meta-features including Reverse ReLU Silhouette Score and HHI proposed in this study have a significant effect on the classification performance. (1) The meta-features HHI proposed in this study was significant in the classification performance. (2) The number of variables has a significant effect on the classification performance, unlike the number of classes, but it has a positive effect. (3) The number of classes has a negative effect on the performance of classification. (4) Entropy has a significant effect on the performance of classification. (5) The Reverse ReLU Silhouette Score also significantly affects the classification performance at a significant level of 0.01. (6) The nonlinearity of linear classifiers has a significant negative effect on classification performance. In addition, the results of the analysis by the classification algorithms were also consistent. In the regression analysis by classification algorithm, Naïve Bayes algorithm does not have a significant effect on the number of variables unlike other classification algorithms. This study has two theoretical contributions: (1) two new meta-features (HHI, Reverse ReLU Silhouette score) was proved to be significant. (2) The effects of data characteristics on the performance of classification were investigated using meta-features. The practical contribution points (1) can be utilized in the development of classification algorithm recommendation system according to the characteristics of datasets. (2) Many data scientists are often testing by adjusting the parameters of the algorithm to find the optimal algorithm for the situation because the characteristics of the data are different. In this process, excessive waste of resources occurs due to hardware, cost, time, and manpower. This study is expected to be useful for machine learning, data mining researchers, practitioners, and machine learning-based system developers. The composition of this study consists of introduction, related research, research model, experiment, conclusion and discussion.

• Geotechnical Engineering
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• v.12 no.4
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• pp.157-178
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• 1996

Current design methods for reinforced earth structures take no account of the magnitude of the strains induced in the tensile members as these are invariably manufactured from high modulus materials, such as steel, where straits are unlikely to be significant. With fabrics, however, large strains may frequently be induced and it is important to determine these to enable the stability of the structure to be assessed. In the present paper internal design method of analysis relating to the use of fabric reinforcements in reinforced earth structures for both stress and strain considerations is presented. For the internal stability analysis against rupture and pullout of the fabric reinforcements, a strain compatibility analysis procedure that considers the effects of reinforcement stiffness, relative movement between the soil and reinforcements, and compaction-induced stresses as studied by Ehrlich 8l Mitchell is used. I Bowever, the soil-reinforcement interaction is modeled by relating nonlinear elastic soil behavior to nonlinear response of the reinforcement. The soil constitutive model used is a modified vertsion of the hyperbolic soil model and compaction stress model proposed by Duncan et at., and iterative step-loading approach is used to take nonlinear soil behavior into consideration. The effects of seepage pressures are also dealt with in the proposed method of analy For purposes of assessing the strain behavior oi the fabric reinforcements, nonlinear model of hyperbolic form describing the load-extension relation of fabrics is employed. A procedure for specifying the strength characteristics of paraweb polyester fibre multicord, needle punched non-woven geotHxtile and knitted polyester geogrid is also described which may provide a more convenient procedure for incorporating the fablic properties into the prediction of fabric deformations. An attempt to define improvement in bond-linkage at the interconnecting nodes of the fabric reinforced earth stracture due to the confining stress is further made. The proposed method of analysis has been applied to estimate the maximum tensions, deformations and strains of the fabric reinforcements. The results are then compared with those of finite element analysis and experimental tests, and show in general good agreements indicating the effectiveness of the proposed method of analysis. Analytical parametric studies are also carried out to investigate the effects of relative soil-fabric reinforcement stiffness, locked-in stresses, compaction load and seepage pressures on the magnitude and variation of the fabric deformations.

• Journal of the Korean Geotechnical Society
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• v.31 no.5
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• pp.5-21
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• 2015

An energy pile is a novel type of ground heat exchangers (GHEX's) which sets up heat exchange pipes inside a pile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with the surrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structural foundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with various configurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heat exchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-type heat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated with consideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate the thermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hours operating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through the thermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchange amount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economic feasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demanded expenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipes and labor cost.

• Journal of Korean Home Economics Education Association
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• v.17 no.2
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• pp.221-238
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• 2005

This study analyzed the contents of the milk-related nutrition education currently found in elementary and secondary school textbooks. An attempt was made to develop the basic data needed to in the future provide students with pertinent in formation regarding the nutritional attributes of milk, as well as the desired consumption behavior, within the school education system. To attain the objectives of this study, the researcher analyzed the contents of the milk-related nutrition education described in elementary and secondary school textbooks(1st-10th grades). Based on the results of this analysis, measures were developed to organize the contents of the milk-related nutrition education that should be taught within the school education system. At the elementary school level, milk-related nutrition education was included in the textbooks for the integrated curriculum for the lower grades, as well as in the science, practical arts, and physical education textbooks for every grade, except the End and the 6th. The practical arts textbook, which contained basic knowledge related to the nutritional attributes of milk and the proper method in which to intake milk, was found to be the one which dealt with milk-related nutrition education in the most detail. At the secondary school level. milk-related nutrition education was included in the 7th-10th grade textbooks for the science, technology and home economics, and physical education courses. In this instance. the technology and home economics textbooks were the ones which were found to contain the most milk-related nutrition education covering such aspects as the nutritional attributes of milk, the special characteristics of milk as a food. how to select and store milk. as well as how to use milk as part of a balanced diet in everyday life. However, as was the case at the elementary school levet the repetitious nature of the milk-related contents found in the textbooks for various school subjects and at different school levels, as well as the inefficient hierarchical structure in which the knowledge is presented, were identified as key problems. There is a need to establish the appropriate milk-related nutrition education for each school level. The need to develop education programs, which could be linked to the school subjects and special milk programs, was also emphasized.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.39-51
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• 2003

Objectives: The Profile of Mood States (POMS) has been used broadly and frequently in various medical studies with various subjects. For the development and application of the Korean edition of POMS, called K-POMS, we translated POMS into Korean and then evaluated the reliability and validity of K-POMS. Methods: The subjects were 161 male students with a mean age of 18.1 years (15-30) and 244 female students with a mean age of 16.6 years (14-23). They were requested to perform K-POMS and SCL-90-R (Korean version) at the same time. Means, reliability coefficients, and test-retest correlations of K-POMS were calculated. Content validities, correlations with SCL-90-R, and discrimination validities in comparison with 76 depressive patients were obtained, and factor analyses were carried out. Results: Mean scores of Total Mood Disturbance (TMD) and some subscales (T, F, C, V factor) showed a significant difference between male and female students. The internal consistency coefficient ($\alpha$) of the total 65 items was 0.93, and ranged from 0.67 to 0.90 for subscales. Test-retest correlations of 43 subjects ranged from 0.27 to 0.63. Seven psychiatrists rated the properness of the content of each item as more than moderate degree (mean scale points=2.66, in the range of 0 to 4). Every subscale of KPOMS exhibited significant correlation with the matching subscale of SCL-90-R. Mean scores of K-POMS of the total 405 subjects were significantly different from those of the 76 depressive subjects after age correction. Six factors were extracted, accounting for 51.2% of total variance. Factor 6 consisted of 6 items which came from various subscales of POMS and represented "uncertainty and helplessness," which may be somewhat different to depression or sadness proper. Conclusion: The validity and reliability of K-POMS could be confirmed. The significant difference in K-POMS scores between depressive subjects and normal subjects suggests that K-POMS can be used clinically for the evaluation and screening of depression. The main structure of K-POMS is very similar to that of POMS, except the Confusion-Bewilderment factor which shows weak factor consistency in K-POMS. This may reflect some emotional characteristic of Koreans such as an undifferentiated aspect of cognitive efficiency. The sixth factor newly extracted from K-POMS also may be indicative of an unique emotional aspect of young Koreans.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.654-661
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• 1999

Background : The upper respiratory tract is the primary target organ of various airborne pollutants and is easily accessible part of the respiratory tract, and also is the predominant structure where chronic cough originates. The nasal peak inspiratory flow(PIFn), which is the peak inspiratory flow via nose with nasal mask and spirometry, could be a reliable parameter of nasal obstruction. The validity of PIFn has been evaluated in several studies by assessing the correlation between PIFn measurements and other parameters of nasal air flow. This study was designed to show the reproducibility of PIFn, the difference of PIFn between patients with chronic cough and normal subjects, and the usefulness of PIFn in the evaluation of nasal obstruction in patients with chronic cough. Methods : PIFn was measured by spirometry with nasal mask, twice a day for 3 consecutive days in 7 young normal subjects to evaluate validity of the test. In 32 patients with chronic cough and 25 age-matched normal subjects, PIFn and pulmonary function test($FEV_1$, $FEV_1%$ pred, FVC, and FVC% pred) were measured at first visiting. Results : Values of PIFn, $FEV_1$, and FVC were nearly constant in 7 young normal adults. Patients with chronic cough were 32 (14 males and 18 females) and the mean age was $41.4{\pm}15.9$ years. Normal subjects were 32(22 males and 10 females) and the mean age was $39.8{\pm}18.6$ years. There was no significant difference of age and pulmonary function test between patients with chronic cough and normal subjects(p<0.05). The PIFn values in patients with chronic cough was significantly lower than those of normal subjects($2.25{\pm}0.68\;L/sec$ vs. $2.75{\pm}1.00\;L/sec$ ; p=0.02). The postnasal drip syndrome(PNDS) comprised the majority of patients with chronic cough(27). The PIFn in patients with PNDS was significantly lower than that of normal subjects (mean$\pm$SD ; $2.18{\pm}0.66$ vs. $2.75{\pm}1.00\;L/sec$, p=0.006). Conclusion : There was a significant difference of PIFn between patients with chronic cough and normal subjects. Among the patients with chronic cough, patients with PNDS showed the most significant difference with normal subjects in PIFn. The PIFn could be a useful parameter of nasal obstruction in patients with chronic cough, especially in patients with PNDS.

• Asia pacific journal of information systems
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• v.20 no.3
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• pp.191-204
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• 2010

Recently, the CO2 emission and energy consumption have become critical global issues to decide the future of nations. Especially, the spread of IT products and the increased use of internet and web applications result in the energy consumption and CO2 emission of IT industry though information technologies drive global economic growth. EU, the United States, Japan and other developed countries are using IT related environmental regulations such as WEEE(Waste Electrical and Electronic Equipment), RoHS(Restriction of the use of Certain Hazardous Substance), REACH(Registration, Evaluation, Authorization and Restriction of CHemicals) and EuP(Energy using Product), and have established systematic green business/IT strategies to enhance the competitiveness of IT industry. For example, the Japan government proposed the "Green IT initiative" for being compatible with economic growth and environmental protection. Not only energy saving technologies but energy saving systems have been developed for accomplishing sustainable development. Korea's CO2 emission and energy consumption continuously have grown at comparatively high rates. They are related to its industrial structure depending on high energy-consuming industries such as iron and steel Industry, automotive industry, shipbuilding industry, semiconductor industry, and so on. In particular, export proportion of IT manufacturing is quite high in Korea. For example, the global market share of the semiconductor such as DRAM was about 80% in 2008. Accordingly, Korea needs to establish a systematic strategy to respond to the global environmental regulations and to maintain competitiveness in the IT industry. However, green competitiveness of Korea ranked 11th among 15 major countries and R&D budget for green technology is not large enough to develop energy-saving technologies for infrastructure and value chain of low-carbon society though that grows at high rates. Moreover, there are no concrete action plans in Korea. This research aims to deduce the priorities of the Korean green business/IT strategies to use multi attribute weighted average method. We selected a panel of 19 experts who work at the green business related firms such as HP, IBM, Fujitsu and so on, and selected six assessment indices such as the urgency of the technology development, the technology gap between Korea and the developed countries, the effect of import substitution, the spillover effect of technology, the market growth, and the export potential of the package or stand-alone products by existing literature review. We submitted questionnaires at approximately weekly intervals to them for priorities of the green business/IT strategies. The strategies broadly classify as follows. The first strategy which consists of the green business/IT policy and standardization, process and performance management and IT industry and legislative alignment relates to government's role in the green economy. The second strategy relates to IT to support environment sustainability such as the travel and ways of working management, printer output and recycling, intelligent building, printer rationalization and collaboration and connectivity. The last strategy relates to green IT systems, services and usage such as the data center consolidation and energy management, hardware recycle decommission, server and storage virtualization, device power management, and service supplier management. All the questionnaires were assessed via a five-point Likert scale ranging from "very little" to "very large." Our findings show that the IT to support environment sustainability is prior to the other strategies. In detail, the green business /IT policy and standardization is the most important in the government's role. The strategies of intelligent building and the travel and ways of working management are prior to the others for supporting environment sustainability. Finally, the strategies for the data center consolidation and energy management and server and storage virtualization have the huge influence for green IT systems, services and usage This research results the following implications. The amount of energy consumption and CO2 emissions of IT equipment including electrical business equipment will need to be clearly indicated in order to manage the effect of green business/IT strategy. And it is necessary to develop tools that measure the performance of green business/IT by each step. Additionally, intelligent building could grow up in energy-saving, growth of low carbon and related industries together. It is necessary to expand the affect of virtualization though adjusting and controlling the relationship between the management teams.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.145-153
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• 2013

It is a global trend that the water management policy is shifting from a water quality-oriented assessment to the aquatic ecosystem-based assessment. The majority of aquatic ecosystem assessment systems were developed solely based on physicochemical factors (e.g., water quality and bed structure) and a limited number of organisms (e.g., plankton and benthic organisms). Only a few systems use plants for a health assessment, although plants are sensitive indicators reflecting long-term disturbances and alterations in water regimes. The development of an assessment system is underway to evaluate and manage lakes as ecosystem units in the Korean Ministry of Environment. We reviewed the existing multivariate health assessment methods of other leading countries, and discussed their applicability to Korean lakes. The application of multivariate assessment methods is costly and time consuming, in addition to the correlation problem among variables. However, a single variable is not available at this moment, and the multivariate method is an appropriate system due to its multidimensional evaluation and cumulative data generation. We, therefore, discussed multivariate assessment methods in three steps: selecting metrics, scoring metrics and assessing indices. In the step of selecting metrics, the best available metrics are species-related variables, such as composition and abundance, as well as richness and diversity. Indicator species, such as sensitive species, are the most frequently used in other countries, but their system of classification in Korea is not yet complete. In terms of scoring metrics, the lack of reference lakes with little anthropogenic impact make this step difficult, and therefore, the use of relative scores among the investigated lakes is a suitable alternative. Overall, in spite of several limitations, the development of a plant-based multivariate assessment method in Korea is possible using mostly field research data. Later, it could be improved based on qualitative metrics on plant species, and with the emergence of further survey data.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.517-528
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• 2007

Domestic or international existing researches regarding rail damage factors are focused on laying, vehicle conditions, driving speed and driving habits and overlook characteristics of track structure (elasticity, maintenance etc). Also in ballast track, as there is no special lateral spring stiffness of track also called as ballast lateral resistance in concrete track, generally, existing study shows concrete track has 2 time shorter life cycle for rail replacement than ballast track due to abrasion. As a result of domestic concrete track design and operation performance review, concrete track elasticity is lower than track elasticity of ballast track resulting higher damage on rail and tracks. Generally, concrete track has advantage in track elasticity adjustment than ballast track and in case of Europe, in concrete track design, it is recommended to have same or higher performance range of vertical elastic stiffness of ballast track but domestically or internationally review on lateral spring stiffness of track is very minimal. Therefore, through analysis of service line track on site measurement and analysis on performance of maintenance, in this research, dynamic characteristic behaviors of commonly used ballast and concrete track are studied to infer elasticity of service line track and experimentally prove effects of track lateral spring stiffness that influence curved rail damage as well as correlation between track elasticity by track system and rail damage to propose importance of appropriate elastic stiffness level for concrete and ballast track.