• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.582-588
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• 2018

Accident diagnosis is one of the complex tasks for nuclear power plant (NPP) operators. In abnormal or emergency situations, the diagnostic activity of the NPP states is burdensome though necessary. Numerous computer-based methods and operator support systems have been suggested to address this problem. Among them, the recurrent neural network (RNN) has performed well at analyzing time series data. This study proposes an algorithm for accident diagnosis using long short-term memory (LSTM), which is a kind of RNN, which improves the limitation for time reflection. The algorithm consists of preprocessing, the LSTM network, and postprocessing. In the LSTM-based algorithm, preprocessed input variables are calculated to output the accident diagnosis results. The outputs are also postprocessed using softmax to determine the ranking of accident diagnosis results with probabilities. This algorithm was trained using a compact nuclear simulator for several accidents: a loss of coolant accident, a steam generator tube rupture, and a main steam line break. The trained algorithm was also tested to demonstrate the feasibility of diagnosing NPP accidents.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2024-2026
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• 1998

Many power plants built 20-30 years ago are facing problems associated with the excitation system used for controlling generator output voltage. After years of reliable operation, generation is experiencing increased down time due to maintenance associated with the exciting excitation equipment. Reliability of the excitation system has become an issue, especially where many of these generation plants may be critical to the internal processes used for manufacturing. Wear out mechanisms such as those associated with the wire wound rheostat the electromechanical voltage regulator, insulation failures of the rotating exciter and commutator deterioration have become real problems typical of many older installations. These are some of the issues that are affecting system reliability for older power plants. This paper will address typical problems associated with the old excitation systems and the justification for a replacement static excitation system used in many Paper Mills.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1038-1045
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• 2017

To address mounting concerns over global warming, the Paris Agreement was reached in December 2015, which aims to limit the increase in global average temperature. South Korea has set a highly ambitious target to reduce emissions and submitted an Intended Nationally Determined Contribution (INDC). Based on the INDC, we investigated the impact of limiting carbon emissions on the power system and the electricity market in Korea. Through detailed simulations on assumed plausible scenarios, this work highlights a) the effects of different carbon emission targets on the annual carbon emission volumes, generation costs, and carbon price; b) the generation mix changes induced by carbon emission limits; and c) the difference in system marginal price and payments for generator owners that carbon emission constraint creates in electricity markets under three different pricing rules.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.9
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• pp.599-605
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• 2015

The revised U.S. Nuclear Regulatory Commission(NRC), Regulatory Guide(RG) 1.20, rev.3 requires the evaluation of the potential adverse effects from pressure fluctuations and vibrations on piping and components for the reactor coolant, steam, feedwater, and condensate systems. Detailed vibration analyses for the systems attached to the steam generator are very difficult, because these piping systems are very complicated. This paper suggests a screening method for the flow-induced vibration of acoustic resonances and pump-induced vibration of the piping systems attached to the steam generator in order to conduct the APR1400 comprehensive vibration assessment program. This paper seeks to address the areas such as potential vibration sources, and methods to prevent the occurrence of acoustic resonances and pump-induced vibration of piping systems attached to the steam generator, for conducting the APR1400 comprehensive vibration assessment program. The screening method in this paper will be used to estimate the flow-induced vibration of the piping systems attached to the steam generator for the APR1400.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.37-48
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• 2004

The SyncML, the standard synchronization protocol, supports the synchronization of various application services between a client and a server such as an address book, a calendar. Even with this standard protocol, SyncML application developers usually spend a long time and efforts implementing service specific logics and databases. This paper designed and implemented the SDE(Service Development Environment) which is an integrated development environment for SyncML server developers to develop an application service rapidly and correctly. The SDE consists of two components i.e., the Sync Library and the SEG(Sync Engine Generator) tool. To prove the applicability of this study we implemented a SyncML server by using the SDE and also carried out the correctness tests and the performance test. We hope this system helps developers implement mobile application services more efficiently.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.13-27
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• 2017

This paper presents a tool that automatically generates mobile web applications from user interface (UI) models which are based on PELUM (Pattern and Event based Logical User Interface Modeling). PELUM is a method for the effective development of UI-centered embedded systems via UI modeling. The proposed tool consists of a model editor and a code generator. The former provides an environment for modeling a Logical UI Model (LUM) and a Programming Interface Model (PIM) on the web. On the other hand, the code generator sets the screen configuration and events' behavior, according to the LUM, synthesizing a local database schema according to the PIM, and then generates an executable mobile web app. It also can produce mashup web apps by receiving an open API address via the PIM. The generated mobile web apps follow the Model-View-Controller (MVC) architecture in order for users to easily customize them. The proposed tool enables them to generate mobile web apps that can be executed on various devices by modeling logical UIs on the web.

• International Journal of Computer Science & Network Security
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• v.23 no.7
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• pp.49-60
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• 2023

The amount of data generated by electronic systems through e-commerce, social networks, and data computation has risen. However, the security of data has always been a challenge. The problem is not with the quantity of data but how to secure the data by ensuring its confidentiality and privacy. Though there are several research on cloud data security, this study proposes a security scheme with the lowest execution time. The approach employs a non-linear time complexity to achieve data confidentiality and privacy. A symmetric algorithm dubbed the Non-Deterministic Cryptographic Scheme (NCS) is proposed to address the increased execution time of existing cryptographic schemes. NCS has linear time complexity with a low and unpredicted trend of execution times. It achieves confidentiality and privacy of data on the cloud by converting the plaintext into Ciphertext with a small number of iterations thereby decreasing the execution time but with high security. The algorithm is based on Good Prime Numbers, Linear Congruential Generator (LGC), Sliding Window Algorithm (SWA), and XOR gate. For the implementation in C, thirty different execution times were performed and their average was taken. A comparative analysis of the NCS was performed against AES, DES, and RSA algorithms based on key sizes of 128kb, 256kb, and 512kb using the dataset from Kaggle. The results showed the proposed NCS execution times were lower in comparison to AES, which had better execution time than DES with RSA having the longest. Contrary, to existing knowledge that execution time is relative to data size, the results obtained from the experiment indicated otherwise for the proposed NCS algorithm. With data sizes of 128kb, 256kb, and 512kb, the execution times in milliseconds were 38, 711, and 378 respectively. This validates the NCS as a Non-Deterministic Cryptographic Algorithm. The study findings hence are in support of the argument that data size does not determine the execution.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.2 s.332
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• pp.49-56
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• 2005

In this paper, we propose a memory BIST Circuit Creation System which creates BIST circuit based on user defined fault model and generates the optimized march test algorithm. Traditional tools have some limit that regenerates BIST circuit after changing the memory type or test algorithm. However, this proposed creation system can automatically generate memory BIST circuit which is suitable in the various memory type and apply algorithm which is required by user. And it gets more efficient through optimizing algorithms for fault models which is selected randomly according to proposed nile. In addition, it support various address width and data and consider interface of IEEE 1149.1 circuit.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.3
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• pp.243-249
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• 2015

In direct vehicle teleoperation, a human operator drives a vehicle at a distance through a pair of master and slave device. However, if there is time delay, it is difficult to remotely drive the vehicle due to slow response. In order to address this problem, we introduced a novel methodology of shared vehicle teleoperation using a virtual driving interface. The methodology was developed with four components: 1) virtual driving environment, 2) interface for virtual driving environment, 3) path generator based on virtual driving trajectory, 4) path following controller. Experimental results showed the effectiveness of the proposed approach in simple and cluttered driving environment as well. In the experiments, we compared two sampling methods, fixed sampling time and user defined instant, and finally merged method showed best remote driving performance in term of completion time and number of collision.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1717-1732
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• 2015

The widespread use of location-based services (LBSs), which allows untrusted service provider to collect large number of user request records, leads to serious privacy concerns. In response to these issues, a number of LBS privacy protection mechanisms (LPPMs) have been recently proposed. However, the evaluation of these LPPMs usually disregards the background knowledge that the adversary may possess about users' contextual information, which runs the risk of wrongly evaluating users' query privacy. In this paper, we address these issues by proposing a generic formal quantification framework,which comprehensively contemplate the various elements that influence the query privacy of users and explicitly states the knowledge that an adversary might have in the context of query privacy. Moreover, a way to model the adversary's attack on query privacy is proposed, which allows us to show the insufficiency of the existing query privacy metrics, e.g., k-anonymity. Thus we propose two new metrics: entropy anonymity and mutual information anonymity. Lastly, we run a set of experiments on datasets generated by network based generator of moving objects proposed by Thomas Brinkhoff. The results show the effectiveness and efficient of our framework to measure the LPPM.