• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.3
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• pp.425-437
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• 2017

For efficient hardware (HW) implementation of elliptic curve cryptography (ECC), various sub-modules for the underlying finite field operations should be implemented efficiently. Among these sub-modules, modular inversion (MI) requires the most computation; therefore, its performance might be a dominant factor of the overall performance of an ECC module. To determine the most efficient MI algorithm for an HW ECC module, we implement various classes of MI algorithms and analyze their performance. In contrast to the common belief in previous research, our results show that the right-shift binary inversion (RS) algorithm performs well when implemented in hardware. In addition, we present optimization methods to reduce the area overhead and improve the speed of the RS algorithm. By applying these methods, we propose a new RS-variant that is both fast and compact. The proposed MI module is more than twice as fast as the other two classes of MI: shifting Euclidean (SE) and left-shift binary inversion (LS) algorithms. It consumes only 15% more area and even 5% less area than SE and LS, respectively. Finally, we show that how our new method can be applied to optimize an HW ECC module.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.454-460
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• 2003

In this paper, we present a novel method of parallelization of the modular multiplication algorithm to improve time and space complexity on RNS (Residue Number System). The parallel algorithm executes modular reduction using new table lookup based reduction method. MRS (Mixed Radix number System) is used because algebraic comparison is difficult in RNS which has a non-weighted number representation. Conversion from residue number system to certain MRS is relatively fast in residue computer. Therefore magnitude comparison is easily Performed on MRS. By the analysis of the algorithm, it is known that it requires only 1/2 table size than previous approach. And it requires 0(ι) arithmetic operations using 2ㅣ processors.

• Journal of Power Electronics
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• v.16 no.1
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• pp.163-172
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• 2016

The modular multilevel converter (MMC) has been receiving increased attentions in recent years. The new modular multilevel converter is a derivative topology from the traditional MMC in which the number of sub-modules (SMs) necessitated by each phase can be reduced by one. This paper presents a phase-shifted carrier pulse-width modulation (PSC-PWM) for the new MMC with an optimal phase-shifted angle to suppress the harmonics of the output voltage. Further, the harmonic features when the capacitor voltage of the middle SM is selected as two different values are also investigated. Moreover, in order to avoid introducing an unnecessary dc offset current at the ac terminals of the new MMC, a novel capacitor voltage balancing scheme is proposed by adjusting the amplitude of the reference signals rather than the offset. Finally, the validity and effectiveness of the proposed modulation and balancing schemes have been verified by experimental results based on a three-phase prototype of the new MMC.

• KIEAE Journal
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• v.17 no.5
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• pp.87-94
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• 2017

Purpose: Prefabricated modular space such as a container construction has recently been interested unlike the conventional construction method, and their scale have expanded from small buildings such as cafes, houses and pensions to shopping centers, complex cultural spaces where shows and exhibitions are possible doing. In this way, the container is in the spotlight as an advantage such as mobility, flexibility, correspondence, economic efficiency, recyclability and so on. However, there are no specific guidelines and standard design methods in aspects of structural calculation, functional insulation and environmental configuration. Therefore, as the first step to resolve these problems, this study has focused on the field of environmental performance of container construction, presented appropriate guidelines and searched ways to improve performances. Method: For this study, seven types of the modular building were chosen and compared, and their energy performances have been analyzed using a proven simulation tool. Essential methodology and terminology were examined to estimate and judge their efficiency. Result: In conclusion, energy performances depend on specific configuration of combined unit spaces, and design guidelines cold be set up for promoting their use in the practical field.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.2
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• pp.49-60
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• 2023

Purpose: This study aims to establish detailed spatial planning by identifying the needs for a seclusion module for emergency psychiatric patients. Methods: The necessity of medical space with seclusion function was analyzed from spatial, medical, and social perspectives. The needs for a space capable of performing three medical functions: protection, isolation, and treatment, was analyzed. Among various types of mobile medical facilities, seclusion space was considered suitable for utilizing modular construction methods, as it is the most rational method that can satisfy the environmental level of fixed healthcare facilities' space. Therefore, seclusion modules based on modular construction were planned, consisting of two protective units for stabilizing patients with psychiatric illness, one for treatment unit that can accommodate both internal and external treatment, and another one for an infectious disease isolation unit equipped with negative pressure equipment. Implications: This study analyzed the necessary medical functions of the interior space of the mobile stabilization module based on the spatial analysis of existing medical facilities, and proposed alternative spatial configurations according to treatment, seclusion, isolation functions.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.5
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• pp.241-249
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• 2003

This paper describes a novel approach for performing eigenvalue analysis and frequency domain analysis of multi-machine power system. The salient feature of this approach is a direct approach for constructing the state matrix equations of linearized power systems about its operating point using modular technique. These state matrix equations are then used to obtain eigenvalues and mode shapes of the system, and frequency response, or Bode, plots of selected transfer functions. The proposed program provides a flexible tool for systematic analyses of tuning PSS's parameters. The paper also presents its application to the analyses of a single-machine infinite bus system and two-area system with 4 machines.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.4
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• pp.147-147
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• 2003

This paper describes the finite element analysis(FEA) for the design of electromagnet for Control Element Drive Mechanism(CEDM) in System-integrated Modular Advanced Reactor(SMART) and compared with the lifting power characteristics of prototype electromagnet. A thermal analysis was performed for the electromagnet. A model for the thermal analysis of the electromagnet was developed and theoretical bases for the model were established. It is important that the temperature of the electromagnet windings be maintained within the allowable limit of the insulation. since the electromagnet of CEDM is always supplied with current during the reactor operation. So the thermal analysis of the winding insulation which is composed of polyimide and air were performed by finite element method. As a result, it is shown that the characteristics of prototype electromagnet have a good agreement with the results of FEA. The thermal properties obtained here will be used as input for the optimization analysis of the electromagnet.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2743-2759
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• 2020

A detailed computational fluid dynamics (CFD) simulation analysis model was developed using ANSYS CFX 16.1 and analyzed to simulate the basic design and internal flow characteristics of a 180 MW small modular reactor (SMR) with a natural circulation flow system. To analyze the natural circulation phenomena without a pump for the initial flow generation inside the reactor, the flow characteristics were evaluated for each output assuming various initial powers relative to the critical condition. The eddy phenomenon and the flow imbalance phenomenon at each output were confirmed, and a flow leveling structure under the core was proposed for an optimization of the internal natural circulation flow. In the steady-state analysis, the temperature distribution and heat transfer speed at each position considering an increase in the output power of the core were calculated, and the conceptual design of the SMR had a sufficient thermal margin (31.4 K). A transient model with the output ranging from 0% to 100% was analyzed, and the obtained values were close to the T_hot and T_cold temperature difference value estimated in the conceptual design of the SMR. The K-factor was calculated from the flow analysis data of the CFX model and applied to an analysis model in RELAP5/MOD3.3, the optimal analysis system code for nuclear power plants. The CFX analysis results and RELAP analysis results were evaluated in terms of the internal flow characteristics per core output. The two codes, which model the same nuclear power plant, have different flow analysis schemes but can be used complementarily. In particular, it will be useful to carry out detailed studies of the timing of the steam generator intervention when an SMR is activated. The thermal and hydraulic characteristics of the models that applied porous media to the core & steam generators and the models that embodied the entire detail shape were compared and analyzed. Although there were differences in the ability to analyze detailed flow characteristics at some low powers, it was confirmed that there was no significant difference in the thermal hydraulic characteristics' analysis of the SMR system's conceptual design.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.489-498
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• 2012

Most of the software reliability models are based on black box approach and these models consider the entire software system as a single unit. Present day software development process has changed a lot. In present scenario these models may not give better results. To overcome this problem an improved additive model has been proposed in this paper, to estimate the reliability of software with modular structure. Also the concept of imperfect debugging has been also considered. A maximum likelihood estimation technique has been used for estimating the model parameters. Comparison has been made with an existing model. ${\chi}^2$ goodness of fit has been used for model fitting. The proposed model has been validated using real data.