• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.5
• /
• pp.34-40
• /
• 2015

This paper presents an application of Differential Search (DS) meta-heuristic optimization algorithm for optimal operation of micro grid system. DS algorithm has the benefit of high convergence rate and precision compared to other optimization methods. The micro grid system consists of a wind turbine, a diesel generator, and a fuel cell. The simulation is applied to micro grid system only. The wind turbine generator is modeled by considering the characteristics of variable output. One day load data which is divided every 20 minute and wind resource for wind turbine generator are used for the study. The method using the proposed DS algorithm is easy to implement, and the results of the convergence performance are better than other optimization algorithms.

• Communications for Statistical Applications and Methods
• /
• v.22 no.5
• /
• pp.507-518
• /
• 2015

It is not easy to select a linear mixed model since the main interest for model building could be different and the number of parameters in the model could not be clearly defined. In this paper, performance of conditional Akaike Information Criteria and its bias-corrected version are compared with marginal Bayesian and Akaike Information Criteria through a simulation study. The results from the simulation study indicate that bias-corrected conditional Akaike Information Criteria shows promising performance when candidate models exclude large models containing the true model, but bias-corrected one prefers over-parametrized models more intensively when a set of candidate models increases. Marginal Bayesian and Akaike Information Criteria also have some difficulty to select the true model when the design for random effects is nested.

• Transactions of Materials Processing
• /
• v.23 no.5
• /
• pp.297-302
• /
• 2014

The current paper introduces work that was conducted during the development of a stamping die for a reinforce center pillar made from high strength steel. In the current study, the Bauschinger effect on the springback analysis was studied by comparing simulation results with real panels, which are currently in production. For a complicated part shape, quantitative measurements of the deformed shape are not easy in general to obtain. An adjustment procedure of the shape data for some chosen sections has been suggested to improve the accuracy of the quantitative measurements. The results show that the kinematic hardening model provides more accurate results.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.1092-1096
• /
• 1988

This paper presents a research on the development of a system which manages be tool data for the factory using NC machines. The tool information concerning each production stages of the industry is studied in the CIM(Computer Integrated Manufacturing) view point. The system gives the characteristics of the easy and reliable processing of the tool data by the help of menu and graphic functions. The DBMS(Data Base Management System) having relational model is used for the system build-up and is interfaced with CAD system for display of the tool geometry.

• Journal of Information Technology Services
• /
• v.7 no.4
• /
• pp.221-230
• /
• 2008

Green's relations are five equivalence relations that characterize the elements of a semigroup in terms of the principal ideals. The J relation is one of Green's relations. Although there are known algorithms that can compute Green relations, they are not useful for finding all J relations in the semigroup of all $n{\times}n$ Boolean matrices. Its computation requires multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices. The size of the semigroup of all $n{\times}n$ Boolean matrices grows exponentially as n increases. It is easy to see that it involves exponential time complexity. The computation of J relations over the $5{\times}5$ Boolean matrix is left an unsolved problem. The paper shows theorems that can reduce the computation time, discusses an algorithm for efficient J relation computation whose design reflects those theorems and gives its execution results.

• Korean Journal of Remote Sensing
• /
• v.24 no.5
• /
• pp.417-425
• /
• 2008

An image-based atmospheric correction software ATC is implemented using MATLAB and SML (Spatial Modeler Language in ERDAS IMAGINE), and it was tested using Landsat TM/ETM+ data. This ATC has two main functional modules, which are composed of a semiautomatic type and an automatic type. The semi-automatic functional module includes the Julian day (JD), Earth-Sun distance (ESD), solar zenith angle (SZA) and path radiance (PR), which are programmed as individual small functions. For the automatic functional module, these parameters are computed by using the header file of Landsat TM/ETM+. Three atmospheric correction algorithms are included: The apparent reflectance model (AR), one-percent dark object subtraction technique (DOS), and cosine approximation model (COST). The ACT is efficient as well as easy to use in a system with MATLAB and SML.

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.465-469
• /
• 1995

We have investigated the effects of deposition angle on structural and magnetic properties of e-beam evaporated ${(4-{\AA}\;Co/9.2-{\AA}\;Pt)}_{23}$ multilayer thin films prepared on tilted substrates. It was found that the [111] crystallographic orientations of the multilayer thin films were not aligned with colummar growth orientations and they were remained to be normal to the substrate planes even though the deposition angle was severely oblique up to $60^{\circ}$. The analysis of the torque curve reveal that the intrinsic anisotropy energy was monotonically decreased with the deposition angle but the easy axis orientation parallel to the substrate normal was not much influenced by deposition angle.

• Analytical Science and Technology
• /
• v.34 no.5
• /
• pp.231-239
• /
• 2021

Detection of fire accelerants from fire residues is critical to determine whether the case was arson or accidental fire. However, to develop a standardized model for determining the presence or absence of fire accelerants was not easy because of high temperature which cause disappearance or combustion of components of fire accelerants. In this study, logistic regression, random forest, and support vector machine models were trained and evaluated from a total of 728 GC-MS analysis data obtained from actual fire residues. Mean classification accuracies of the three models were 63 %, 81 %, and 84 %, respectively, and in particular, mean AU-PR values of the three models were evaluated as 0.68, 0.86, and 0.86, respectively, showing fine performances of random forest and support vector machine models.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.47 no.5
• /
• pp.407-408
• /
• 2021

Extraction of impacted third molars is a routine procedure performed by oral and maxillofacial surgeons. However, extractions in middle-aged or elderly individuals are not easy, and there are several factors that need to be considered. These factors include decreased healing potential and the risk of complications increasing with age. In addition, third molars can often be fully or deeply impacted in middle-aged individuals, and pathologic changes, such as cysts, caries, or periodontitis of the adjacent second molar, can develop. Furthermore, the rate of ankylosis and systemic disease increases after middle age. It is considered that these factors acting alone or in combination increase the difficulty of extraction.

• Journal of the Korean Society of School Health
• /
• v.32 no.2
• /
• pp.88-95
• /
• 2019

Purpose: The prevalence of binge drinking has increased among Korean adolescents in recent years. The purpose of this study was to determine the influencing factors of adolescent binge drinking. Methods: This was a secondary analysis of data from the 14th Korea Youth Risk Behavior Survey. For the present analysis, 5,203 binge drinkers (girls who drank 3 or more glasses of soju and boys who drank 5 or more in average on one occasion in the last 30 days) and 4,464 non-binge drinkers were selected. Results: Compared with the adolescents who had no experience buying alcoholic beverages, the adolescents who responded that it was easy or uneasy to buy alcoholic drinks were more likely to be a binge drinker. Also, compared with never smokers, ex-smokers and current smokers were more likely to be a binge drinker. Binge drinking was positively associated with skipping breakfast, subjective health, and feelings of sadness or hopeless. Conclusion: The findings of this study may be useful in developing binge drinking prevention programs for adolescents.