• New & Renewable Energy
• /
• v.3 no.3
• /
• pp.14-19
• /
• 2007

A flow channel model of a bipolar plate with varying cross-sectional area was newly designed for improving performance and efficiency of a PEM fuel cell stack. As a result, the varying cross-sectional area model showed poor uniformity in velocity distribution, however, maximum velocity in the flow path is about 30% faster than that of the uniform cross-sectional area model. The proposed varying cross-sectional area model is expected to diffuse operating fluids more easily into diffusion layer because it has relatively higher values in pressure distribution compared with other flow channel models. It is expected that the implementation of the varying cross-sectional area model can reduce not only the mass transport loss but also the activation loss in a PEM fuel cell, and open circuit voltage of a fuel cell can thus be increased slightly.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.18 no.4
• /
• pp.317-335
• /
• 2014

In this work, we investigate the global stability analysis of a viral infection model with antibody immune response. The incidence rate is given by a general function of the populations of the uninfected target cells, infected cells and free viruses. The model has been incorporated with two types of intracellular distributed time delays to describe the time required for viral contacting an uninfected cell and releasing new infectious viruses. We have established a set of conditions on the general incidence rate function and determined two threshold parameters $R_0$ (the basic infection reproduction number) and $R_1$ (the antibody immune response activation number) which are sufficient to determine the global dynamics of the model. The global asymptotic stability of the equilibria of the model has been proven by using Lyapunov theory and applying LaSalle's invariance principle.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.2
• /
• pp.17-24
• /
• 2019

In this paper, we propose a new model for predicting effective Win/Loss in professional baseball game in Korea using machine learning technique. we used basic baseball data and Sabermetrics data, which are highly correlated with score to predict and we used the deep learning technique to learn based on supervised learning. The Drop-Out algorithm and the ReLu activation function In the trained neural network, the expected odds was calculated using the predictions of the team's expected scores and expected loss. The team with the higher expected rate of victory was predicted as the winning team. In order to verify the effectiveness of the proposed model, we compared the actual percentage of win, pythagorean expectation, and win percentage of the proposed model.

• Journal of the Semiconductor & Display Technology
• /
• v.22 no.1
• /
• pp.54-58
• /
• 2023

In this study, we compared the detection accuracy of the parameters of the scaffold failure detection model. A detection algorithm based on convolutional neural network was used to construct a failure detection model for scaffold. The parameter properties of the model were changed and the results were quantitatively verified. The detection accuracy of the model for each parameter was compared and the parameter with the highest accuracy was identified. We found that the activation function has a significant impact on the detection accuracy, which is 98% for softmax.

• Communications for Statistical Applications and Methods
• /
• v.30 no.5
• /
• pp.501-516
• /
• 2023

Knowledge distillation (KD) refers to extracting knowledge from a large and complex model (teacher) and transferring it to a relatively small model (student). This can be done by training the teacher model to obtain the activation function values of the hidden or the output layers and then retraining the student model using the same training data with the obtained values. Recently, relational KD (RKD) has been proposed to extract knowledge about relative differences in training data. This method improved the performance of the student model compared to conventional KDs. In this paper, we propose a new method for RKD by introducing a new loss function for RKD. The proposed loss function is defined using the area difference between the teacher model and the student model in a specific hidden layer, and it is shown that the model can be successfully compressed, and the generalization performance of the model can be improved. We demonstrate that the accuracy of the model applying the method proposed in the study of model compression of audio data is up to 1.8% higher than that of the existing method. For the study of model generalization, we demonstrate that the model has up to 0.5% better performance in accuracy when introducing the RKD method to self-KD using image data.

• Journal of Korea Multimedia Society
• /
• v.19 no.2
• /
• pp.396-404
• /
• 2016

In this paper, the customized sport convergence contents curation system is proposed for activation of sport for all. The proposed system collects and analyzes profile of social sports group(club, society, etc.) for recommend optimized sport convergence contents to user. And the survey is progressed for research problem of existed service and usefulness of proposed service. The proposed system and service are expected to design innovative new service model for activate of sport for all.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.18 no.4
• /
• pp.89-97
• /
• 2012

Demands for sports activities for the disabled are continuously increasing. Although sports centers where the disabled available are compartmentalized into the disabled sports centers and the public sports facilities, in fact, sports activities for the disabled in the public facilities had limits. Therefore, this study draw current states, features and issue related spaces and programs of the public sports centers in order to seek ways to activate sports activities for the disabled. The results of the study as follows. Firstly, setting up the legal regulation about the disabled sports centers. Secondly, improvement the facilities considered the disabled's characteristic. Thirdly, installation of a shower stall and a locker room for various users. Fourthly, positive application of the outdoor space connected with a swimming pool. Fifthly, laying detailed regulation of sports centers for the disabled. In conclusion, the study on architectural model which related with spaces and programs of the sports center for all people is needed to move forward.

• IMMUNE NETWORK
• /
• v.1 no.3
• /
• pp.196-202
• /
• 2001

Backgorund: WEHI-231 B cell line is a representative model for $IgM^+$ mature B cells. To understand the signaling differences between mature and immature B cells, we compared the responsiveness of WEHI-231 and Bal 17 B cell lines to BCR cross-linking. Methods: The extents of tyrosine phosphorylation, ligand-induced internalization, and activation-induced cell death upon BCR cross-linking were compared in two cell lines. Results: Despite a higher expression of BCR, cross-linking of BCR on WEHI-231 cell evoked a weaker level of tyrosine phosphorylation and BCR endocytosis than Bal 17 cells. Furthermore, the endocytosed BCR could not enter the lysosomal compartment and stayed as peripheral spots in WEHI-231 cells. Conclusion: WEHI-231 cell showed preferred BCR-mediated signaling pathways leading to a reduced capability of antigen presentation as well as the enhanced apoptosis in comparision with Bal 17 cells. These results might reflect the signaling differences between mature and immature B cells.

• Preventive Nutrition and Food Science
• /
• v.12 no.3
• /
• pp.131-134
• /
• 2007

The kinetic analyses for thermal products of alpha-, gamma- and delta-tocopherols during heating as functions of temperature and time were studied. Alpha-, gamma- and delta-tocopherols dissolved in glycerol were heated at $100{\sim}200^{\circ}C$ for $5{\sim}60$ min. The thermal products were separated by hexane extraction and analyzed by HPLC using a reversed phase ${\mu}-Bondapak$ $C_{18}-column$ with two kinds of elution solvents in a gradient mode. The formation kinetics of thermal products of tocopherols followed a first-order kinetic model. The formation rate of thermal products of tocopherols was dependent on heating temperatures and heating times. The activation energy and enthalpy for the thermal products of ${\gamma}-and$ ${\delta}-tocopherols$ were higher than those for ${\alpha}-tocopherol$ as in the case of the oxidative degradation kinetics of tocopherol. The magnitude order of the activation energy was ${\gamma}->{\delta}->{\alpha}-tocopherol$.

• Knowledge Management Research
• /
• v.21 no.1
• /
• pp.151-173
• /
• 2020

The purpose of this study is to identify the antecedents that impact on the individual knowledge sharing based on motivational perspectives. Specifically, the authors investigate the roles of general self-efficacy and popularity on knowledge sharing drawn on costly signaling theory and trait activation theory. Data from 227 pairs of employees and coworkers working in companies located in South Korea supported the model. General self-efficacy was positively related to knowledge sharing and popularity was positively associated to knowledge sharing. Also, by taking an interactional approach, our study demonstrated the moderating effect of popularity on the relationship between general self-efficacy and knowledge sharing. The positive relationship between general self-efficacy and knowledge sharing is significant when popularity is low, but not significant when popularity is high. Our findings suggest that the various motivation types including intrinsic and extrinsic motivations for knowledge sharing of individuals exist simultaneously and these motivations have an interactive effect on knowledge sharing.