• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.49-60
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• 2021

The Core Protection Calculator System (CPCS) is vital for plant safety as it ensures the required Specified Acceptance Fuel Design Limit (SAFDL) are not exceeded. The CPCS generates trip signals when Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) exceeds their predetermined setpoints. These setpoints are established based on the operating margin from the analysis that produces the SAFDL values. The goal of this research is to create a simplified CPCS that optimizes operating margin for I-SMRs. Because the I-SMR is compact in design, instrumentation placement is a challenge, as it is with Ex-core detectors and RCP instrumentation. The proposed CPCS addresses the issue of power flux measurement with In-Core Instrumentation (ICI), while flow measurement is handled with differential pressure transmitters between Steam Generators (SG). Simplification of CPCS is based on a Look-Up-Table (LUT) for determining the CEA groups' position. However, simplification brings approximations that result in a loss of operational margin, which necessitates compensation. Appropriate compensation is performed based on the result of analysis. FPGAs (Field Programmable Gate Arrays) are presented as a way to compensate for the inadequacies of current systems by providing faster execution speeds and a lower Common Cause Failure rate (CCF).

• Journal of Information Technology Services
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• v.10 no.2
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• pp.163-176
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• 2011

In the current Internet environment, there may exist a number of independently-operating authentication systems even within a single organization, according to the service types and service providing entities. Current silo-style isolated authentication system model has revealed critical problems in the aspects of usability, cost-effectiveness, extensibility and flexibility, and privacy protection. Recently, several next generation authentication systems have been actively developed by leading industrial and standardization institutions. This paper firstly analyzes the problems of current Internet authentication system environments. And then, the underlying idea, operating procedures, and pros and cons of the newly developed next generation authentication systems are analyzed so as to provide the selection guidelines for the new authentication systems and drive further development directions for future Internet authentication systems.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.93-99
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• 2014

This study aims to explore and analyze smartphone users' characteristics from the two perspectives (purchase vs. use characteristics) on the two operating systems (iOS and Android). The results of the study on purchase characteristics show that smartphones choice priority and the gender ratio are found to be significantly different between the two operating system users. However, the replacement cycle is not statistically different from iOS and Android users. The results of study on use characteristics show that the number of the applications and the registered SNS(social network service), the average monthly smartphone bill, and satisfaction are significantly different between iOS and Android users. However, the average Internet usage time is not different between the two operating system users. The findings provide useful implications for operating developers, smartphone manufacturers, and application developers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.2
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• pp.55-70
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• 2006

In this paper, we propose a new access control security architecture for supporting flexibility in Secure Operating Systems. By adding virtual access control system layer to the proposed security architecture, various access control models such as MAC, DAC, and RBAC can be applied to Secure Operating Systems easily. The proposed security architecture is designed to overcome the problem of Linux system's base access control system. A policy manager can compose various security models flexibly and apply them to Operating Systems dynamically. Also, the proposed architecture is composed of 3 modules such as access control enforcement, access control decision, and security control. And access control models are abstracted to hierarchy structure by virtual access control system. And, we present the notation of policy conflict and its resolution method by applying various access control model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.10-22
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• 2010

The first full-scale u-City operation has started in Dongtan u-City. As local cities take over and operate the u-City, unexpected issues arise such as securing the budget of operating costs and self-providing the costs with business models utilizing the u-City assets. The paper presents a strategy for solving these issues. The strategy provides a foundation(infrastructure) for long-term operation models which may reduce the long-term operating costs. In order to establish the economic operating framework of u-City, suggested are some cost-reduction models based on the operating costs structure. For each model, a base framework with comparative analysis of operating costs is provided. With these models, each u-City may select a relevant model according to the characteristics of it. We hope that the framework provides the foundation for efficient and sustainable u-City operations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.8
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• pp.457-462
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• 2003

This paper presents an optimal operating strategy of distributed generation (DG) with reliability worth evaluation of distribution systems. Using DG for peak-shaving unit could reduce the overall system operating cost, and using DG for standby power unit could reduce the customer interruption cost. If DG operating cost is less than utility power cost in peak time, DG should be running to reduce the overall system operating cost. When customer interruption cost enlarges, however, standby power strategy may be the better operating strategy than peak-shaving strategy. Selection of whether DG should be operated for peak-shaving or for standby power, needs the accurate reliability worth evaluation and the accurate power cost evaluation. Instead of using annual average reliability worth, the concept of hourly reliability worth is introduced in this paper to determine the optimal operating decision of DG. Applying suggested hourly reliability worth, the distribution companies that possess DG could set up the optimal operating strategy of DG.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.3
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• pp.141-152
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• 2007

In this paper, we present a network-oriented lightweight real-time system, which is composed of an event-driven operating system called the Embedded Lightweight Operating System (ELOS) and a generic multi hop ad hoc routing protocol suite. In the ELOS, a conditional preemptive FCFS scheduling method with a guaranteed time slot is designed for efficient real-time processing. For more elaborate configurations, we reinforce fault tolerance by supplementing semi-auto configuration using wireless agent nodes. The developed hardware platform is also introduced, which is a scalable prototype constructed using off-the-shelf components. In addition, in order to evaluate the performance of the proposed system, we developed a ubiquitous network test-bed on which several experiments with respect to various environments are conducted. The results show that the ELOS is considerably favorable for tiny ubiquitous networked systems with real-time constraints.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.1003-1008
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• 2017

The Internet of Things has attracted considerable research attention in recent years. In order for the new IoT technology to be widely used, the reliability and protection of information is required. IoT systems are very vulnerable to physical security due to their easy accessibility. Along with the development of SoC technology, many operating systems have been developed and many new operating systems have been introduced. In this paper, we describe the vulnerability analysis results for operating systems running on the ARMv7 Thumb Architecture hardware platform. For the recently introduced "Windows 10 IoT Core" operating system, I implemented the Zero-Day Attack by implanting the penetration code developed through the research into a specific IoT system. The virus detection test for the resulting penetration code was validated by referral to the "virustotal" site.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.173-178
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• 2015

Cloud systems are efficient models that can utilize various infrastructures, platforms, and applications regardless of the type of clients. This paper proposes a cloud-based integrated development environment (IDE) for robot software development which would make software development easier. The proposed system provides robot simulation to test the robot HW modules or robot systems for development and testing of software operating in a robot system with two or more different operating systems (OS) such as Windows, Linux, and real-time OS. This paper implements and evaluates the proposed system using OPRoS [33].

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.732-737
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• 2001

The mathematical method was developed and numerical analyses were carried out with various parameters to provide substantial data for optimal design and operation of urban utility systems. The composition of systems and their specifications, such as co-generation system, heat pump system, incineration system and other heating and cooling system could be obtained through these analyses for various resource and energy requirements in urban area. As results the system constituents and operating characteristics, and their economic performances such as the value of objective function, initial and an operating costs were discussed for various load patterns. The effective system design method and the excepted effects of the several unused energy recovery systems were also briefly discussed with the variation of the buildings and facilities species and their capacities.