• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.282-285
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• 1998

This paper presents a method to evaluate the effect of voltage sag in distribution system using the component reliability data of utilities. The proposed method is based on Specified CBEMA curve which is the probability curve of the customers' effect by voltage sag. We carried out the experiment for the customers' sensitive equipments using the test facilities in KERI. The Monte Carlo method and the historical reliability data in KEPCO are used for simulations.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.194-201
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• 2003

This study presents the comparative filtration performance evaluation of automotive fuel filters based on the theory of Beta ratio. For the experiments, the fuel component's test stand incorporating the multi-pass filtration test circuit was developed. A mathematical description of filtration process in general was derived. And the theoretical basis of multi-pass test and the test procedure were described in detail. Experimental results revealed that domestic fuel filter tested could not maintain consistent Beta ratio, that is filtration efficiency, although it had the holding capacity of contaminants close to the specification at maximum pressure drop across the filter assembly. The results of experiments and simulations also showed that filtration system model could be refined including desorption ratio to estimate the variable Beta ratio in service life.

• Earthquakes and Structures
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• v.13 no.6
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• pp.599-611
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• 2017

This paper improves seismic fragility of a typical steel-concrete composite bridge with the deck-to-pier connection joint configuration at the concrete crossbeam (CCB). Based on the quasi-static test on a typical steel-concrete composite bridge model under the SEQBRI project, the damage states for both of the critical components, the CCB and the pier, are identified. The finite element model is developed, and calibrated using the experimental data to model the damage states of the CCB and the bridge pier as observed from the experiment of the test specimen. Then the component fragility curves for both of the CCB and the pier are derived and combined to develop the system fragility curves of the bridge. The uncertainty associated with the mean system fragility has been discussed and quantified. The study reveals that the CCB is more vulnerable than the pier for certain damage states and the typical steel-concrete composite bridge with CCB exhibits desirable seismic performance.

• KDI Journal of Economic Policy
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• v.41 no.3
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• pp.39-75
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• 2019

An emphasis on public-private partnership (PPP) in the regulatory policy process can overcome the challenges hindering regulatory effectiveness with the emergence of fast developing technologies and new industries. This study attempts to evaluate quantitatively different aspects of institutional settings of South Korean regulatory policy in terms of stakeholder engagement as PPP, using evidence-based data released by the OECD. From the results of the principal component analysis, South Korea can be evaluated as being at a very good level overall in its institutional establishment. Nevertheless, the fact that the outcome of regulatory reforms in South Korea is still insufficient compared with this well-established system suggests that the country should concentrate on improving system operation. Consequently, this study makes policy suggestions to improve regulatory effectiveness through PPP by supplementing the facets that are well-equipped but not feasible with respect to regulatory policy cycle, regulatory governance, regulatory method, and conflict resolution.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1412-1420
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• 2018

An experiment was performed using the large-scale test facility (LSTF), which simulated a 1% vessel upper head small-break loss-of-coolant accident with an accident management (AM) measure under an assumption of total-failure of high-pressure injection (HPI) system in a pressurized water reactor (PWR). In the LSTF test, liquid level in the upper head affected break flow rate. Coolant was manually injected from the HPI system into cold legs as the AM measure when the maximum core exit temperature reached 623 K. The cladding surface temperature largely increased due to late and slow response of the core exit thermocouples. The AM measure was confirmed to be effective for the core cooling. The RELAP5/MOD3.3 code indicated insufficient prediction of primary coolant distribution. The author conducted uncertainty analysis for the LSTF test employing created phenomena identification and ranking table for each component. The author clarified that peak cladding temperature was largely dependent on the combination of multiple uncertain parameters within the defined uncertain ranges.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.272-276
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• 2021

Presently, Online / Offline Users are facing cyber attacks every day. These cyber attacks affect user's performance, resources and various daily activities. Due to this critical situation, attention must be given to prevent such users through cyber attacks. The objective of this research paper is to improve the IDS systems by using machine learning approach to develop a hybrid model which controls the cyber attacks. This Hybrid model uses the available KDD 1999 intrusion detection dataset. In first step, Hybrid Model performs feature optimization by reducing the unimportant features of the dataset through decision tree, support vector machine, genetic algorithm, particle swarm optimization and principal component analysis techniques. In second step, Hybrid Model will find out the minimum number of features to point out accurate detection of cyber attacks. This hybrid model was developed by using machine learning algorithms like PSO, GA and ELM, which trained the system with available data to perform the predictions. The Hybrid Model had an accuracy of 99.94%, which states that it may be highly useful to prevent the users from cyber attacks.

• Journal of Semiconductor Engineering
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• v.2 no.1
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• pp.125-129
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• 2021

As the interest of deep learning, techniques to control the color of images in image processing field are evolving together. However, there is no clear standard for color, and it is not easy to find a way to represent only the color itself like the color-palette. In this paper, we propose a novel color palette extraction system by chroma fine-tuning with reinforcement learning. It helps to recognize the color combination to represent an input image. First, we use RGBY images to create feature maps by transferring the backbone network with well-trained model-weight which is verified at super resolution convolutional neural networks. Second, feature maps are trained to 3 fully connected layers for the color-palette generation with a generative adversarial network (GAN). Third, we use the reinforcement learning method which only changes chroma information of the GAN-output by slightly moving each Y component of YCbCr color gamut of pixel values up and down. The proposed method outperforms existing color palette extraction methods as given the accuracy of 0.9140.

• Journal of Information Processing Systems
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• v.18 no.1
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• pp.159-172
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• 2022

The role of the interconnect network, which connects computing nodes to each other, is important in high-performance computing (HPC) systems. In recent years, the peripheral component interconnect express (PCIe) has become a promising interface as an interconnection network for high-performance and cost-effective HPC systems having the features of non-transparent bridge (NTB) technologies. OpenSHMEM is a programming model for distributed shared memory that supports a partitioned global address space (PGAS). Currently, little work has been done to develop the OpenSHMEM library for PCIe-interconnected HPC systems. This paper introduces a prototype implementation of the OpenSHMEM library through a switchless interconnect network using PCIe NTB to provide a PGAS programming model. In particular, multi-interrupt, multi-thread-based data transfer over the OpenSHMEM shared memory model is applied at the implementation level to reduce the latency and increase the throughput of the switchless ring network system. The implemented OpenSHMEM programming model over the PCIe NTB switchless interconnection network provides a feasible, cost-effective HPC system with a PGAS programming model.

• Annual Conference of KIPS
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• 2022.11a
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• pp.40-42
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• 2022

People's focus steadily shifted toward fashion as a popular aesthetic expression as their quality of life improved. Humans are inevitably drawn to things that are more aesthetically appealing. This human proclivity has resulted in the evolution of the fashion industry over time. However, too many clothing alternatives on e-commerce platforms have created additional obstacles for clients in recognizing their suitable outfit. Thus, in this paper, we proposed a personalized Fashion Recommender system that generates recommendations for the user based on their previous purchases and history. Our model aims to generate recommendations using an image of a product given as input by the user because many times people find something that they are interested in and tend to look for products that are like that. In the system, we first reduce data dimensionality by component analysis to avoid the curse of dimensionality, and then the final suggestion is generated by neural network. To create the final suggestions, we have employed neural networks to evaluate photos from the H&M dataset and a nearest neighbor backed recommender.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.26-36
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• 2013

Purpose of this study is to develop virtual components and environment for developing a controller of an Active Air Suspension System in laboratory that slough off existing development environment using real vehicle test. This paper presents an air spring modeling and analysis of air suspension system for a commercial vehicle. Preferentially, It was performed vehicle test for pneumatic system and an air spring for characteristic analysis of system. Each component of an air spring suspension system was developed through emulations and modeling of system for pressure and height sensors in the basis on test results in SILS environment. Non-linear characteristics of air spring are accounted for using the measured data. Also, pressure and volume relations for vehicle hight control is considered. After performance verification of virtual model was performed, we developed virtual environment based on HILS for an Active Air Suspension System. We studied estimation and verification technology for control algorithm that developed.