• Journal of Korean Society of Transportation
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• v.29 no.4
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• pp.43-51
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• 2011

Since a variety of factors are associated with crash occurrence, the analysis of causes of crash is a hard task for traffic researchers and engineers. Among contributing factors leading to crash, the characteristics of driver is of keen interest. This study attempted to identify factors affecting the severity of pedestrian in the collision between pedestrian and vehicle. In particular, our analyses were focused on the novice driver. A binary logistic regression technique was adopted for the analyses. The results showed that driver's age, crash location, and the frequency of violations were dominant factors for the severity. Findings are expected to be useful information for deffective policy- and education-based countermeasures.

• The Journal of Industrial Distribution & Business
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• v.10 no.12
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• pp.35-42
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• 2019

Purpose : This study examines The impact of human resource investment in internal control on stock price crash risk. Effective internal control ensures that information provided is complete and accurate, financial statements are reliable. By overseeing management, internal control systems can reduce agency costs between management and outside parties. In Korea, firms have to disclose information about internal control systems. The working experience of human resources in internal control systems is also provided for interested parties. If a firm hires more experienced internal control personnel, it can better facilitate the disclosure of information. Prior studies reported that information asymmetry between managers and investors increases future stock price crash risk. Therefore, the longer working experience internal control personnel have, the lower probability stock crashes have. Research design, data and methodology : This study analyzed the association between the working experience of internal control personnel and crash risk using regression analysis on KOSPI listed companies for fiscal years 2016 through 2017. The sample consists of 1,034 firm-years of non-financial firms whose fiscal year end on December 31. Career spanning data of internal control personnel was collected from internal control reports. The professionalism(IC_EXP) was measured as the logarithm of the average working experience of internal control personnel in months. Negative conditional skewness(NSKEW) and down-to-up volatility (DUVOL) are used to measure firm-specific crash risk. Both measures are based on firm-specific weekly returns derived from the expanded market model. Results : We find that work experience in internal control environment is negatively related to stock price crashes. Specifically, skewness(NSKEW) and volatility (DUVOL) are reduced when firms have longer tenure of human resources in internal control division. The results imply that firms with experienced internal control personnel are less likely to experience stock price crashes. Conclusions : Stock price crashes occur when investors realize that stock prices have been inflated due to information asymmetry. There is a learning effect when internal control processes are done repetitively. Thus, firms with more experienced internal control personnel could manage their internal control more effectively. The results of this study suggest that firms could decrease information asymmetry by investing in human resources for their internal control system.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.873-882
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• 2012

Dual Phase (DP) steel which has a soft ferrite phase and a hard martensite phase reveals both high strength and high ductility and has received increased attention for use in automotive applications. To conduct structural analysis to verify vehicle safety, highly credible experimental results are required. In this study, tensile tests were performed in a strain rate range from $10^{-4}/s$ to 300/s for Sink Roll-Less (SRL) hot-dip metal coated sheets. Collision properties were estimated through simulation by LS-DYNA using the stress-strain curve obtained from the tensile test. The simulation results were compared with the actual crash test results to confirm the credibility of the simulation. In addition, a tensile test and a crash test with 2% prestrain and a baking (PB) specimen were evaluated identically because automotive steel is used after forming and painting. The mechanical behaviors were improved with an increasing strain rate regardless of the PB treatment. Thus, plastic deformation with an appropriate strain rate is expected to result in better formability and crash characteristics than plastic deformation with a static strain rate. The ultimate tensile strength (UTS) and absorbed energy up to 10% strain were improved even though the total elongation decreased after PB treatment, The results of the experimental crash test and computer simulation were slightly different but generally, a similar propensity was seen.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.399-407
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• 2022

Energy absorption facilities installed on roads should follow the performance standards of the real-car crash test of 'Installation and Maintenance Guidelines for Roadside Safety Facilities'. However, due to different installation conditions, such as differing structure widths on roads, some energy absorption facilities do not provide adequate performance. In order to apply varied environments on roads, an energy absorption structure was designed in this study with 150 mm height and four layers of W-shape guardrail at 200 mm intervals, and the performance was verified using LS-DYNA computer simulation. Through a real-car crash test, the performance of the facility designed by LS-DYNA was tested and was found to meet the performance of the CC2 category for crash cushions. The conclusion of the comparison demonstrates that the simulation and the real-car crash tests are both significant.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.90-102
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• 2022

Currently, in our society with a substantial and increasing fraction of the elderly population, transport safety for elderly drivers is becoming the center of attention. However, deficient data on vehicle crashes in South Korea limits the growth of traffic accident research pertaining to the country. So, we complemented South Korean vehicle crash data by examining USA vehicle crash data, especially the data of Ohio State, and analyzing the influential factors of elderly driver-involved crashes of the State. Subsequently, we suggested a way of improving the South Korean dataset. Notably, our study showed that the influential factors were vehicle speed, posted speed, and following other vehicles too close and provided them in the South Korean dataset.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.97-104
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• 2008

Many atypical structures on the roadside are exposed to traffics unshielded posing great danger. One way to shield an atypical structure to secure the occupant safety is to stack energy absorbing material modules in front of the structure. This paper presents the analysis method of module type crash cushion made of EPS blocks using simple energy balance of the car and crash cushion and numerical examples for 0.9ton-500km/h, 0.9ton-60km/h and 0.9ton-70km/h impact are presented. This method gives simple estimation of maximum acceleration, time of crash, whether or not the vehicle stops completely before whole cushion is being crushed. However, since the acceleration and velocity data from the analysis is so crudely spaced that calculation of safety indices such is RA and OIV is not possible. Problem is overcome by using data interpolation. The spline and linear interpolation is introduce and safety analysis is made and the results are compared.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.115-122
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• 2012

Automobile collision analysis is composed of various shapes, and the speed variation working to the vehicle during collision are utilized as a very important factor in evaluating the degree of vehicle collision or passenger safety. So, the method of analyzing result values on the speed variation utilizing collision analysis program become necessary. This study utilized PC-Crash program in order to compare actual values and analyzed values of braking distance with the friction coefficient of road surface according to vehicle velocity. As a result, the smaller friction coefficient found to be larger error, and the maximum error range of collision velocity in case of each different vehicles (MATIZ, SONATA, or BUS) at the intersection showed 1.2%, 1.8%, 3.1% according to the difference of vehicle weight. Moreover, an accidental fall at IN-CHEON large bridge in order to reappear was verified with practicing simulation which has a slight error.

• Architectural research
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• v.25 no.1
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• pp.1-9
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• 2023

Structural ageing influences the structural performance in a negative way by reducing the seismic resilience of the structure which makes it a major concern around the world. Retrofitting is considered to be a pragmatic and feasible solution to address this issue. Numerous retrofitting techniques are devised by researchers over the years. The viability of using steel bracings as retrofitting component is evaluated on a G+30 storied building model designed according to ACI318-14 and ASCE 7-16. Four different types of steel bracing arrangements (V, Inverted V/ Chevron, Cross/ X, Diagonal) are assessed in the model developed in commercial nu-merical analysis software while considering both material and geometric nonlinearities. Reducing displacement and cost in the structures indicates that the design is safe and economical. Therefore, the purpose of this article is to find the best bracing system that causes minimum displacement, which indicates maximum lateral stiffness. To evaluate the seismic vulnerability of each system, incremental dynamic analysis was conducted to develop fragility curves, followed by the formation of collapse margin ratio (CMR) as stipulated in FEMA P695 and finally, a cost estimation was made for each system. The outcomes revealed that the effects of ge-ometric nonlinearity tend to evoke hazardous consequences if not considered in the structural design. Probabilistic seismic and economic probes indicated the superior performance of V braced frame system and its competency to be a germane technique for retrofitting.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.89-98
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• 2007

Crashworthiness design is of special interest in automotive industry and in the transportation safety field to ensure the vehicle structural integrity and more importantly the occupant safety in the event of the crash. Front side assembly is one of the most important energy absorbing components in relating to the crashworthiness design of vehicle. The structure and shape of the front side assemblies are different depending on automakers. Thus, it is not easy to grab an insight on designer's intention when you glance at a new front side member without experiences. In this paper, we have performed the explicit nonlinear dynamic finite element analysis on the front side assembly of a passenger car to identify the mechanical roles of each part of the assembly and to enhance the absorbing energy from the viewpoint of reverse engineering.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.227-235
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• 2018

Along with the recent increase in traffic volume of vehicles, accidents involving rollover of vehicles have been rapidly increased, resulting in an increase casualties. And to prevent this, various technologies such as vehicle crash test equipment and analysis program development have been advanced. In this study, the applied vehicle model is FORD EXPLORER model, and PC-Crash program for vehicle collision analysis is used to predict the rollover accident behavior of SUV and the collision velocity. Compared with the actual rollover behavior of SUV through the FMVSS No 208 regulations, the analysis results showed similar results, the characteristics of the collision velocity and roll angle showed a tendency that the error rate slightly increased after 1000 msec. Then, as a result of considering using the database of NHTSA, it is shown that the rollover accident occur most frequently in the range of the collision velocity of 15~77 km/h and the collision angle of $22{\sim}74^{\circ}$. And it is possible to estimate the vehicle speed and collision time when the vehicle roof is broken by reconstructing the vehicle starting position, the roof failure position and the stop position by applying the actual accident case.