• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.45 no.1
• /
• pp.34-45
• /
• 2009

In this study, the hydrodynamic coefficients were measured using various nettings to analyze the change of drag coefficients and lift coefficients as a basic study for deriving hydrodynamic coefficients. The data on hydrodynamic force obtained from the flume tank tests were used to compare and analyze the hydrodynamic coefficients based on Reynolds number. Standardized hydrodynamic coefficients were then assumed during the analysis procedures. The hydrodynamic coefficients were measured using the 9 kinds of nettings in which had the same total projected area with different diameters and mesh-grouping ratio. These different netting systems : mesh-grouping ratio. The results of the test of nettings were as follows; First, the drag coefficients of nettings increased when the higher attack angles applied, and decreased with the increased flow speed and netting twine diameter. Second, the lift coefficients of nettings showed the increased values until the attack angle 30 degree, but decreased for the attack angle over 40 degree. Third, the hydrodynamic coefficients of netting decreased as the Reynolds number increased, and reach at slightly states in the highest numbers. Fourth, the hydrodynamic coefficients were derived from a functional formula considering attack angles and Reynolds number, and presented in the three dimensional space.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.5
• /
• pp.462-469
• /
• 2005

A top-down approach is known to be a useful and effective technique for the design and analysis of metabolic systems. In this Study, we have constructed a grouped metabolic network for Lactococcus lactis under aerobic conditions using grouped enzyme kinetics. To test the usefulness of grouping work, a non-grouped system and grouped systems were compared quantitatively with each other. Here, grouped Systems were designed as two groups according to the extent of grouping. The overall simulated flux values in grouped and non-grouped models had pretty similar distribution trends, but the details on flux ratio at the pyruvate branch point showed a little difference. This result indicates that our grouping technique can be used as a good model for complicated metabolic networks, however, for detailed analysis of metabolic network, a more robust mechanism Should be considered. In addition to the data for the pyruvate branch point analysis, Some major flux control coefficients were obtained in this research.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2003.11a
• /
• pp.259-262
• /
• 2003

Group technology(GT) is a manufacturing philosophy which identifies and exploits the similarity of parts and processes in design and manufacturing. A specific application of GT is cellular manufacturing. the first step in the preliminary stage of cellular manufacturing system design is cell formation, generally known as a machine-part cell formation(MPCF). This paper presents and tests a grouping gentic algorithm(GGA) for solving the MPCF problem and uses the measurements of e(ficacy. GGA's replacement heuristic used similarity coefficients is presented.

• Communications for Statistical Applications and Methods
• /
• v.29 no.4
• /
• pp.441-451
• /
• 2022

In the era of bigdata, scalability is a crucial issue in learning models. Among many others, the Alternating Direction of Multipliers (ADMM, Boyd et al., 2011) algorithm has gained great popularity in solving large-scale problems efficiently. In this article, we propose applying the ADMM algorithm to solve the least square problem penalized by the pairwise-difference penalty, frequently used to identify group structures among coefficients. ADMM algorithm enables us to solve the high-dimensional problem efficiently in a unified fashion and thus allows us to employ several different types of penalty functions such as LASSO, Elastic Net, SCAD, and MCP for the penalized problem. Additionally, the ADMM algorithm naturally extends the algorithm to distributed computation and real-time updates, both desirable when dealing with large amounts of data.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.1
• /
• pp.61-72
• /
• 2001

The effects of wave groups on reflection and transmission over a submerged breakwater are studied by using a hydrodynamic numerical model and five independent wave grouping parameters. Based on qualitative analyses of limited data, it is found that the reflection and transmission coefficients of submerged breakwater may be strongly correlated with the incident wave groups. The reflection and transmission coefficients tend to decrease as wave groups become relatively larger. In particular, the reflection and transmission coefficients due to wave groups are evaluated smaller than those of single incident waves. However, the reflection and transmission coefficients are not affected by the interval of higher wave groups. It is finally concluded that the mean of nul-length among wave grouping parameters can be an useful parameter for correlating the wave groups with the reflection and transmission coefficients of submerged breakwater.

• Journal of Korean Institute of Industrial Engineers
• /
• v.22 no.4
• /
• pp.705-718
• /
• 1996

A similarity coefficient based algorithm is proposed to solve the machine cells and part families formation problem in group technology. Similarity coefficients are newly designed from the machine-part incidence matrix. Machine cells are formed using a recurrent neural network in which the similarity coefficients are used as connection weights between processing units. Then parts are assigned to complete the cell composition. The proposed algorithm is applied to 30 different kinds of problems appeared in the literature. The results are compared to those by the GRAFICS algorithm in terms of the grouping efficiency and efficacy.

• Journal of Korean Institute of Industrial Engineers
• /
• v.33 no.3
• /
• pp.349-354
• /
• 2007

A mixture experiment is a special type of the response surface experiment in which the factors are the components of a mixture, and the response variable is a function of the proportions of each component. When a new mixture product is developed, there are a large number of components, and the first objective of the experiment is to identify the ones that are most important by doing a screening experiment. We propose a method of screening mixture components using the correlation coefficients when t-tests cannot identify significant components.

• Journal of Institute of Control, Robotics and Systems
• /
• v.19 no.8
• /
• pp.725-730
• /
• 2013

This paper proposed a novel method for an analysis feature of an Electroencephalogram (EEG) at all channels simultaneously. In a BCI (Brain-Computer Interface) system, EEGs are used to control a machine or computer. The EEG signals were weak to noise and had low spatial resolution because they were acquired by a non-invasive method involving, attaching electrodes along with scalp. This made it difficult to analyze the whole channel of EEG signals. And the previous method could not analyze multiple stimuli, the result being that the BCI system could not react to multiple orders. The method proposed in this paper made it possible analyze multiple-stimuli by grouping the channels. We searched the groups making the largest correlation coefficient summation of every member of the group with a BHS (Binary Harmony Search) algorithm. Then we assumed the EEG signal could be written in linear summation of groups using concentration parameters. In order to verify this assumption, we performed a simulation of three subjects, 60 times per person. From the simulation, we could obtain the groups of EEG signals. We also established the types of stimulus from the concentration coefficient. Consequently, we concluded that the signal could be divided into several groups. Furthermore, we could analyze the EEG in a new way with concentration coefficients from the EEG channel grouping.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1995.04a
• /
• pp.122-129
• /
• 1995

This paper presents a similarity coefficient based approach to the problem of machine-part grouping for cellular manufacturing. The method uses relevant production data such as part type, production volume, routing sequence to make machine cells and part families for cell formation. A new similarity coefficient using weighted factors is introduced and an algorithm for formation of machine cells and part families is developed. A comparative study of two similarity coefficients - Gupta and seifoddini's method and proposed method - is conducted. A software program using TURBO C has been developed to verify the implementation.

• International Journal of Aeronautical and Space Sciences
• /
• v.17 no.4
• /
• pp.455-466
• /
• 2016

Chemical-kinetic parameters of the equilibrium constants to evaluate the reverse rate coefficients in the shock layer of a blunt body and the expanding flows are derived for the temperature range from 300 K to 20,000 K. The expanded equilibrium constants for the chemical reactions of the dissociation, ionization, associative ionization, and neutral and charge exchange reactions of the atmospheric species and carbon materials are proposed in the present work. In evaluating the equilibrium constants, the inter-nuclear potential energies of the molecular species are calculated by the analytical potential function of the Hulburt-Hirschfelder model, and the parameters of the analytical model are determined from the semi-classically calculated RKR potentials. The electronic states and energies of the atoms are calculated by the electronic energy grouping model, and the rovibrational states and energies of each electronic states of the molecules are evaluated by the WKB method. The expanded equilibrium constants for 31 types of the reactions are provided for the best curve-fit functions, and the recombination reaction rate coefficients evaluated from the present equilibrium constants are compared with existing measured values.