• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3888-3910
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• 2018

As an increasing number of defense methods against control-data attacks are deployed in practice, control-data attacks have become challenging, and non-control-data attacks are on the rise. However, defense methods against non-control-data attacks are still deficient even though these attacks can produce damage as significant as that of control-data attacks. We present a method to defend against non-control-data attacks using influence domain monitoring (IDM). A definition of the data influence domain is first proposed to describe the characteristics of a variable during its life cycle. IDM extracts security-critical non-control data from the target program and then instruments the target for monitoring these variables' influence domains to ensure that corrupted variables will not be used as the attackers intend. Therefore, attackers may be able to modify the value of one security-critical variable by exploiting certain memory corruption vulnerabilities, but they will be prevented from using the variable for nefarious purposes. We evaluate a prototype implementation of IDM and use the experimental results to show that this method can defend against most known non-control-data attacks while imposing a moderate amount of performance overhead.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.385-402
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• 1996

Cytotoxicity of dental restorative materials using cell culture technique has been extensively studied by various quantitative assays. The aim of this study was to investigate the microstructural change of damaged L292 cells which could not observed with light microscope. Cytotoxic effect of ZOE, Prisma APH (Densply International Inc., U.S.A.), Clearfil FII(Kuraray Co., Japan), Fuji II(GC Co., Japan) and Fuji II LC(GC Co., Japan) on cultured L292 cells were observed. Irreversible cell damage and cytolysis were found in ZOE and Fuji II groups. In Clearfil FII, mild to moderate cell damage was observed. APH group showed variable cytotoxicity. Moderate cell damage was found in Fuji II LC group. Cytotoxic effect were as follows : A condensation of the chromatin occureds along or adjacent to the inner membrane of the nuclear envelops. The nuclear envelope remained resonably intact but the contents were partially or completely lost. The cell nucleus contains clusters of markedly electron-dense interchromatin granules. The rough endoplasmic reticulum were dilated. In some mitochondira, matrix was disoriented and fused cristae were discernible. Mitochondiral swelling and woolly appearance were recognized. Large vacuoles and autolysosmes were found in cytoplasm. Some breaks of the cytoplasmic membrane and even cytolysis could be seen in dying cells.

• Computers and Concrete
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• 제6권4호
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• pp.319-341
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• 2009

A new formulation based on lumped plasticity and inelastic hinges is presented in this paper for nonlinear analysis of Reinforced Concrete (RC) frame structures. Inelastic hinge behaviour is described using the principles of Continuum Damage Mechanics (CDM). Member formulation contains provisions to model stiffness degradation due to cracking of concrete and yielding of reinforcing steel. Depending on its nature, cracking is classified as concentrated or distributed. Concentrated cracking is accounted through a damage variable and its growth is defined based on strain energy principles. Presence of distributed flexural cracks in a member is taken care of by modelling it as non-prismatic. Plasticity theory supported by effective stress concept of CDM is applied to describe the post-yield response. Nonlinear quasi-static analysis is carried out on a RC column and a wide two-storey RC frame to verify the formulation. The column is subjected to constant axial load and monotonic lateral load while the frame is subjected to only lateral load. Computed results are compared with those due to experiments or other numerical methods to validate the performance of the formulation and also to highlight the contribution of distributed cracking on global response.

• Computers and Concrete
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• 제30권4호
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• pp.289-299
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• 2022

Based on the random cracking theory, the cylinder RVE model of reinforced concrete is established and the damage process is divided into three stages as the evolution of the cracks. The stress distribution along longitude direction of the concrete and the steel bar in the cylinder model are derived. The equivalent elastic modulus of the RVE are derived and the user-defined field variable subroutine (USDFLD) for the equivalent elastic modulus is well integrated into the ABAQUS. Regarding the tensile rebars and the concrete surrounding the rebars as the equivalent homogeneous transversely isotropic material, and the FEM analysis for the reinforced concrete beams is conducted with the USDFLD subroutine. Considering the concrete cracking and interfacial debonding, the macroscopic damage process of the reinforced concrete beam under four-point bending loading in the simulation. The volume fraction of rebar and the cracking degree are mainly discussed to reveal their influence on the macro-performance and they are calibrated with experimental results. Comparing with the bending experiment performed with 8 reinforced concrete beams, the bending stiffness of the second stage and the ultimate load simulated are in good agreement with the experimental values, which verifies the effectiveness and the accuracy of the improved finite element method for reinforced concrete beam.

• Journal of the Korea institute for structural maintenance and inspection
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• 제10권1호
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• pp.190-196
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• 2006

In the existed study, a fire outbreak in a reinforced concrete structure looses the organism by the different contraction and expansion of hardened cement pastes and aggregate, and causes cracks by thermal stress, leading to the deterioration of the durability. So accurate diagnosis of deterioration is needed based on mechanism of fire deterioration in general concrete structures. Fundamental information and data on the Properties of concrete exposed to high temperature are necessary for accurate diagnosis of deterioration. Therefore, This study is willing to propose fundamental data for quick and accurate diagnosis of deteriorated concrete structure by fire damage with making variable concrete test specimen, exposing high temperature environment, observing the explosive spalling and examining engineering property.

• Magazine of the Korea Concrete Institute
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• 제7권2호
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• pp.117-125
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• 1995

In this study, the damage to a concrete br~dge pier due to flre caused by the fall of an oil truck were investigated by the use of FEM and by tensile tests for reinfortements. And thtse results were analyzed and compared with the measured values. In the FEM calculations, the selected variable was the fire temperature $T_a=500-800^{\circ}C$. The fixed values were the heat transition coefficient ${\alpha}=2000W/m^2{\cdot}K$. the initial temperature of concrete $T_0=5{\circ}C$ and the fire duration t=30 minutes. As the results obtained from numerical calculations, the property darrlage zone ap,)eared to be 1.5-4.1cm and the structure damage zone appeared to be 8.7- 10.1cm from the concrete surface. And this results give values very similar to those measured, nanlelv 2-4cm and 8~10cm respectively. The results frorn tensile tests give no serious loss of the tensile strength.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.239-243
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• 2003

A reducing bearing angle theory for bond of ribbed reinforcing bars to concrete is proposed to simulate experimental observation. Analytical expressions to determine bond strength for splitting and pullout failure are derived, where the bearing angle is a key variable. As bearing angle is reduced, splitting strength decreases and shearing strength increases. The proposed reducing bearing angle theory is effective to simulate damage of the deformed bar-concrete interface and understand bond mechanism of ribbed reinforcing steel in concrete structures.

• Journal of Navigation and Port Research
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• 제47권4호
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• pp.202-211
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• 2023

In maritime accidents, collisions involving fishing vessels are more frequent and severe than those involving other types of vessels. Previous cases of collision accidents caused by fishing vessels causing serious damage implied that fishing vessels maintained high speeds until just before the collision and that they collided with much larger vessels. This study investigated the correlation between the severity of ship damage resulting from fishing vessel collisions and the vessel's speed. The effective impact speed commonly used in the road transport sector was utilized to analyze ship collision accidents. The study collected collision data between fishing vessels and between fishing vessels and non-fishing vessels from accident investigation reports from 2016 to 2022. The effective impact speed was calculated for a total of 617 vessels. After using binary and multinomial logistic regression methodology, the analysis was carried out with effective impact speed as the independent variable and severity of accident as the dependent variable. The analysis revealed a statistically significant correlation between the effective impact speed and the severity of ship damage, indicating that the severity of ship damage is influenced not only by the effective impact speed but also by the tonnage of the vessel.

• Journal of Urban Science
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• 제6권2호
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• pp.59-72
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• 2017

Studies on the calculation of accident costs include the approach on calculating damage costs covering all accidents regardless of first or secondary party and the one calculating damage costs generated by a single victim. These two approaches have a limitation of considering a subject for costs analysis as a single entity. In addition, research on estimating the interaction effects caused in the relationship between diverse traffic accident features and factors remains inadequate since most studies focused on calculating costs incurred in a single entity such as a victim, damaged building, or social organization in charge of managing car accident. This study intends to identify the expected range of old age where a specific interaction effect would remain, compare accidents between old age section and the entire age section, and discover an exogenous variable to be applied in accident drop effects in senior people and reduced benefits by calculating and testing additional accident costs in case the first party and the second party all pertain to the senior age section. By classifying the entire accidents caused by old drivers according to the types of cars, significant coefficients representing the influence that affects car accidents according to the characteristics are calculated and set them as the representative variables by selecting top variable in accordance with from low to high order. Furthermore, characteristics on five age groups such as a group of over 65 and less than 70, a group of over 70 and less than 75, a group of over 75 and less than 80, a group of over 80 and less than 85, and a group of over 85 are elicited and compared them with these preselected accident characteristics variables, thereby identifying what changing effects come out.

• Journal of the Korean Society of Safety
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• 제30권6호
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• pp.34-39
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• 2015

The study is aimed to develop fuzzy logic system that has overcurrent and saturation time as input variable and possibility of electrical fire as output variable by making bad conductor area with physical damage to indoor wiring. Most previous studies focused on thermal characteristics depending on the current size and no study considered the current size and saturation time at the same time. Therefore, the paper made into account current value and saturation time together. To this end, it created bad conductor area half the size of IV conductor (1.6 mm) on purpose and transmit electrical current from 10A to 60A by unit of 2A to find out the thermal characteristics and saturation time for current. Based on the data that came out, the study applied fuzzy logic and established the current and saturation time as input variable and chance of fire as output variable. As a result, the center of area of the system that depended only on the existing current value was 75 while the system that applied both current and saturation time presented the chance of fire at 92. It is found that the chance of bad conductor area and deteriorated insulation of electrical wire had current and saturation time as important variables. The data can be used as basic data like deteriorated wire insulation or operation features of circuit breaker in investigating the cause of electrical fire.