• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.61-70
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• 2010

This research presents a methodology to define and apply appropriate index that can measure the risk of regional flood damage. Pressure-State-Response structure has been used to develop the Flood Risk Index(FRI), which allows for a comparative analysis of flood risk assessment between different sub-basins. FRI is a rational assessment method available to improve disaster preparedness and the prevention of losses. The pressure and state index for flood at 117 sub-basins from the year 1980s until the t 10s showed proportional relations, but state index did not decrease even though response index increased. This shows that pressures for flood damage relatively exceed countermeasure for flood. Thus this means we need to strengthen design criteria for flood countermeasure in the future. The FRI is gradually going down in consequence of continuous flood control projects. Flood risk of Han River and Nakdong River area is relatively lower than that of Geum, Seumjin, and Youngsan River area.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.17-28
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• 2024

As listed as one of the most important requirements for Post-Quantum Cryptography standardization process by National Institute of Standards and Technology, the resistance to various side-channel attacks is considered very critical in deploying cryptosystems in practice. In fact, cryptosystems can easily be broken by side-channel attacks, even though they are considered to be secure in the mathematical point of view. The timing attack(TA) and the simple power analysis attack(SPA) are such side-channel attack methods which can reveal sensitive information by analyzing the timing behavior or the power consumption pattern of cryptographic operations. Thus, appropriate measures against such attacks must carefully be considered in the early stage of cryptosystem's implementation process. The Montgomery multiplier is a commonly used and classical gadget in implementing big-number-based cryptosystems including RSA and ECC. And, as recently proposed as an alternative of building blocks for implementing post quantum cryptography such as lattice-based cryptography, the big-number multiplier including the Montgomery multiplier still plays a role in modern cryptography. However, in spite of its effectiveness and wide-adoption, the multiplier is known to be vulnerable to TA and SPA. And this paper proposes a new countermeasure for the Montgomery multiplier against TA and SPA. Briefly speaking, the new measure first represents a multiplication operand without 0 digits, so the resulting multiplication operation behaves in a very regular manner. Also, the new algorithm removes the extra final reduction (which is intrinsic to the modular multiplication) to make the resulting multiplier more timing-independent. Consequently, the resulting multiplier operates in constant time so that it totally removes any TA and SPA vulnerabilities. Since the proposed method can process multi bits at a time, implementers can also trade-off the performance with the resource usage to get desirable implementation characteristics.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.17-26
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• 2008

In this study, the design method of slope reinforced by the earth retention systems were systematically developed, and the flow chart of design procedure fur each system were constructed to design the slope rationally. The proposed design method is composed of 5 steps such as field condition investigation step, slope design step, landslide occurrence prediction step, slope failure scale estimation step and reinforcement countermeasure selection step. The quantitative standard of slope failure scale was established based on the arrangement of various overseas standards which is estimating the slope failure, and the analysis of slope failure scale which is occurred in the country. The slope failure scale is classified into three categories the small scale of slope failure is less than $150m^3$ of slope failure volume, the middle scale of slope failure is from $150m^3$ to $900m^3$ and the large scale of slope failure is more than $900m^3$. The earth retention system could be selected by the proposed slope failure scale based on the slope failure volume. Meanwhile, the design methods of earth retention system such as piles, soil nails and anchors were developed. The optimal countermeasure for slope stability could be proposed using above design methods.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.367-371
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• 2007

Large capacity UPS and emergency generators are being installed and operated at the specific target of important electric facilities that need uninterruptible power supply by the method of countermeasure against power failure for the less reliable incoming power method. Recently, CTTS (Closed Transition Transfer Switch) is being used as uninterruptible power transfer switch at the Common sources of electricity, generator and multiple generators. In this paper, construction plans for uninterruptible power supply system has been suggested in which CTTS has been applied to the secondary of incoming power generator for reliable common dual system method. By briefing the construction of incoming power facilities, large capacity UPS, emergency generator installation space and investment saving effects can be achieved.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.855-863
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• 2015

In this paper, we present a novel method to verify the financial site and prevent sensitive information disclosure with financial security card and smart phone. This method allows homepage access when user accesses to the valid site with right security card and smart phone. Furthermore, traditional OTP method cannot be secure against to Man in the middle attack, but out method presents the countermeasure of this. User can readily recognize the phishing and pharming sites and even avoid Man in the middle attack by malicious users.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.517-524
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• 2004

The leading cause of bridge failures is scouring bed material from around bridge foundations. Many advanced countries such as U.S.A., U.K., the Netherlands and New Zealand have developed and revised their own bridge scour manuals fit for their field conditions. In Korea, researches for reducing bridge failures during floods have concentrated on analysis, laboratory test and countermeasure of bridge scour during the last ten years. however no comprehensive manual for evaluating bridge scour and for identifying the conditions of bridge foundations has been provided yet. In this study, a new bridge scour manual is developed for the accurate evaluation of bridge scour, which reflects domestic field conditions with various streambed materials. The SRICOS method and the Erodibility Index Method are suggested for fine-grained soils and weathered rocks, respectively. In addition, bridge scour analysis algorithms are developed for field engineers to estimate bridge scour depth and to evaluate the susceptibility of bridge scour with ease.

• ETRI Journal
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• v.33 no.2
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• pp.267-274
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• 2011

This paper proposes an efficient masking method for the block cipher SEED that is standardized in Korea. The nonlinear parts of SEED consist of two S-boxes and modular additions. However, the masked version of these nonlinear parts requires excessive RAM usage and a large number of operations. Protecting SEED by the general masking method requires 512 bytes of RAM corresponding to masked S-boxes and a large number of operations corresponding to the masked addition. This paper proposes a new-style masked S-box which can reduce the amount of operations of the masking addition process as well as the RAM usage. The proposed masked SEED, equipped with the new-style masked S-box, reduces the RAM requirements to 288 bytes, and it also reduces the processing time by 38% compared with the masked SEED using the general masked S-box. The proposed method also applies to other block ciphers with the same nonlinear operations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.709-718
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• 2019

A lightweight block cipher CHAM designed for suitability in resource-constrained environment has reasonable security level and high computational performance. Since this cipher may contain intrinsic weakness on side channel attack, it should adopt a countermeasure such as masking method. In this paper, we implement the masked CHAM cipher on 32-bit microprosessor Cortex-M3 platform to resist against side channel attack and analyze their computational performance. Based on the shortcoming of having many round functions, we apply reduced masking method to the implementation of CHAM cipher. As a result, we show that the CHAM-128/128 algorithm applied reduced masking technique requires additional operations about four times.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.135-141
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• 2008

The risk enlargement of cyber infringement and hacking is one of the latest hot issues. To solve the problem, the research for Security Risk Analysis, one of Information Security Technique, has been activating. However, the evaluation for Security Risk Analysis has many burdens; evaluation cost, long period of the performing time, participants’ working delay, countermeasure cost, Security Management cost, etc. In addition, pre-existing methods have only treated Analyzing Standard and Analyzing Method, even though their scale is so large that seems like a project. the Analyzing Method have no option but to include assessors’ projective opinion due to the mixture using that both qualitative and quantitative method are used for. Consequently, in this paper, we propose the Security Risk Analysis Methodology which manage the quantitative evaluation as a project and use Case-Based Reasoning Algorithm for define the period of the performing time and for select participants.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.49-59
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• 2010

Earthquake-induced liquefaction on saturated loose sand is well known in the world. Since Saemangeum Dike Project has a plan to be reclaimed with dredged sand on wide river, possibility of liquefaction should be checked. Section Dongjin5 was selected to evaluate possibility of liquefaction. Estimating method follows as 1) determination of PL value with SPT results, passing curve, and soil properties, 2) prediction for maximum earthquake acceleration, 3) calculation for FL value on depth with Korean specification for highway bridges, 4) visualization for possibility of liquefaction on all of project area with GIS 5) comparison with Japanese specification for highway bridges, Youd and Idriss method, and Andrus and Stokoe II method for verification, 6) ascertainment for the potential liquefaction with cyclic triaxial test. 7) establishing for countermeasure if needed. From the results, even though most of area covered with sand, no potential liquefaction exists except some areas. Those need to soil improvement with grout or attaching measurement on substructure.