• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.539-545
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• 2001

This paper proposes a static synchronous series compensator based on multi-bridge inverter. The proposed system consists of 6 H-bridge modules per phase, which generate 13 pulses for each half period of power frequency. The dynamic characteristic was analyzed by simulations with EMTP code, assuming that it is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works using a scaled model. The proposed system does not require a coupling transformer for voltage injection, and has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.10a
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• pp.90-95
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• 1991

The Uniform Building Code (UBC) is the most widely used requirements for earthquake resistant design in the United States. In this paper, a mid-rise steel building is analyzed by applying 12 sets of actual strong-motion earthquake data that have been scaled to acne 2B levels. The simply extrapolated ground motion displacements are used for the dynamic loads. The results of dynamic analyses for a 10-story steel building are compared with the static and dynamic analysis requirements of UBC-88. It was found that computed lateral fortes using UBC-88 static procedure differed by about 60 percent depending on whether the natural period was computed using the UBC empirical method or the UBC recommended Rayleigh's method. The lateral fortes computed from the UBC response spectra were more than 10 times greater than those computed by UBC static procedures. The lateral forces obtained from both linear and nonlinear analyses using 1989 Loma Prieta ground mot ions compared very well with UBC response spectra results.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.9
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• pp.911-915
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• 2008

Software birthmark is the inherent characteristics that can identify a program. In this paper, we propose a Java class theft detection technique based on static API traces of class files. We utilize control flow analysis to increase resilience, and we apply the semi-global alignment trace comparison algorithm to increase credibility. The credibility and resilience experiments for XML parsers show that our birthmark is more efficient than existing birthmarks.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.5
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• pp.392-399
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• 2008

Accurate measurement of speed and altitude of flying vehicles in air data system remains a critical technical issue. A highly reliable Pitot-static probe is required to obtain air data such as total pressure and static pressure. In this study, an analysis of the characteristics of flowfield around the Pitot-static probe was performed by using a Navier-Stokes CFD code. In addition, for the purpose of finding an optimal configuration, a technique based on the response surface method is applied to the problem with design parameters including shape of the nose section and cone angle. It is shown that the optimal configuration fulfills the MIL specification in wider range of high angles of attack.

• Structural Engineering and Mechanics
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• v.87 no.4
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• pp.347-361
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• 2023

This research aims to assess the behavior of reinforced concrete (RC) residential buildings when moment-resisting frames (MRFs) are used as the lateral resisting system. This investigation was conducted using MIDAS Gen v.19.0. Buildings with various plan footprints (Square, Rectangular, Circular, Triangular, and Plus-Shaped), and different heights (15 m, 30 m, 45 m, and 60 m) are investigated. The defined load cases, the equivalent static lateral load pattern, and the response spectrum function were defined as stated by the American Standard (ASCE 7-16), the 1997 Uniform Building Code (UBC97), the Egyptian Code for Loads (ECP-201), and the European Standard (EC8). Extensive comparisons of the results obtained by the different codes (including the story displacement, the story drift, and the base shear) were undertaken; to assess the response of moment-resisting multi-story framed buildings under lateral loads. The results revealed that, for all study cases under consideration, both ECP-201 and EC8 gave smaller base shear, displacement, and drift by one third to one fourth, around one fourth, around one fifth, respectively for both the ELF and RSA methods if compared to ASCE 7-16 and UBC97.

• Journal of KIISE:Software and Applications
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• v.34 no.3
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• pp.212-218
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• 2007

Not enough verification or enough design of test is not performing in many software developments organization as yet. Therefore, defects that can be detected and corrected during the beginning phases of development are usually found during dynamic testing, it is often observed that testing is inefficient compared to effort for testing. This study aims to suggest a method for effective testing through case study. It is useful in case of not verification and not enough design of test in the previous phase than coding. We show in a concrete way major activities that determine prioritization of testing and level of test case design through static testing, i.e. code review and analysis of code quality. And also we show role between test team and development team.

• The KIPS Transactions:PartA
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• v.13A no.5 s.102
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• pp.399-404
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• 2006

In Jana 2, to enforce a suity policy of a program, programmer writes permission sets required by the code at the policy file, sets Security Manager on system and executes the program. Then Security Manager checks by stack inspection whether an access request to resource should be granted or denied whenever code tries to access critical resource. In this paper, we develop a visualization tool which helps programmers enforce security policy effectively into programs. This system is based on the static permission check analysis which analyzes permission checks which must succeed or fail at each method. Based on this analysis information, programmer can examine visually how permission checks and their stack inspection are performed. By modifying program or policy file if necessary and examining analysis information repeatedly, programmer can enforce security policy correctly.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.4
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• pp.707-724
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• 2024

Recently, Golang has been gaining attention in programming language rankings each year due to its cross-compilation capabilities and high code productivity. However, malware developers have also been increasingly using it to distribute malware such as ransomware and backdoors. Interestingly, Golang, being an open-source language, frequently changes the important values and configuration order of a crucial structure called Pclntab, which includes essential values for recovering deleted symbols whenever a new version is released. While frequent structural changes may not be an issue from a developer's perspective aiming for better code readability and productivity, it poses challenges in cybersecurity, as new versions with modified structures can be exploited in malware development. Therefore, this paper proposes GoAsap, a detection and analysis system for Golang executables targeting the new versions, and validates the performance of the proposed system by comparing and evaluating it against six existing binary analysis tools.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.59-64
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• 2008

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in tooling system of high speed spindle. This paper concerns the static stiffness in the main spindle interface according to variation of clamping force, rotational speed and tool holder shank. Finite element analysis is performed by using a commercial code ANSYS workbench. From the results, it has been shown that the geometry of tool holder shank is mostly influence on the variation of the static stiffness in the main spindle interface.

• Tribology and Lubricants
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• v.24 no.6
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• pp.378-385
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• 2008

In foil bearings, the friction between bumps and their mating surfaces is the major factor which exerts great influence on the bearing performance. From this point of view, many efforts have been made to improve the understanding of the influence of the friction on the foil bearing performance by developing a number of analytical models. However, most of them did not consider the hysteretic behavior of the foil structure resulting from the friction. The present work developed the static structural model in which hysteretic behavior of the friction was considered. The foil structure was modeled using finite element method and the algorithm which determines the conditions of the contact nodes and the directions of the friction forces was used to take into account the friction. The developed model was integrated into the foil bearing prediction code to investigate the effects of the friction on the static performance of the bearing. The results of analysis show that multiple static equilibrium positions are presented for the one static load under the influence of the friction, inferring its great effects on the dynamic performance. However, the effect of friction on the minimum film thickness which determines load capacity of the bearing is negligible.