• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.239-247
• /
• 2015

Recently, various research studies on frontal collision and rear-ender which occur more frequently compared to others are underway as the public interest on them is growing. This study analyzes scientifically the relationship between effective impact speed and injury incidence for vehicle crash accident reconstruction and presents a relevant model formula. Because real vehicle experiments have certain limitations such as possible injuries, this study efforts to collect and analyze as many materials as possible to substitute real vehicle experiments, including data from various collision tests and human experiments. As a result, this study present a threshold in which head-on collisions and rear impacts do not cause injuries under 7 km/h of effective impact speed, and suggests a model formula showing that injury extent is linearly proportional to effective impact speed through collision speed and amount of plastic deformation. In conclusion, a model formula for estimating effective impact speed and injury incidence newly proposed in this study is expected to be used as a minimum standard of judgment in disputes on the injury extent of passenger in head-on collisions and rear impacts. Furthermore its availability in terms of technological analysis in legal arguments is expected to be very high if this study will be enhanced by referring to scientific analyses of various real accidents so as to apply it in various types of collision accidents.

• Journal of The Korean Association of Information Education
• /
• v.21 no.6
• /
• pp.657-664
• /
• 2017

This study investigates the effect of play-based software education instruction strategy for improving computational thinking as a method of software education. The play-based instruction strategy is a teaching-learning strategy in which the presented code is navigated through play, and the functions are revised and newly reconstructed. We designed an education program with the play-based instruction strategy and applied the program to elementary students. In order to verify the effectiveness of the research, we examined the competence of computing thinking concept and computing thinking practice. As a result, the computing thinking concept and computational thinking practice were that the proposed teaching-learning model is higher than the direct teaching method.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.23 no.6
• /
• pp.1207-1217
• /
• 2013

This study utilizes raw data from "Research on the actual condition of firms' information security" of KISA (2010) and constructs panel dataset to analyze a causal relationship between information security investment and security breach. Using Difference in Difference estimation method we find the following results. First, while the usual causality that information security investment reduces security breach is not supported, the reverse causality that security breach increases information security investment is well explained. Second, contrary to the conventional wisdom, firms in the finance/insurance business sector show the most significant reverse causality pattern.

• Communications of Mathematical Education
• /
• v.29 no.3
• /
• pp.533-551
• /
• 2015

Problem posing in school mathematics is generally regarded to make a new problem from contexts, information, and experiences relevant to realistic or mathematical situations. Also, it is to reconstruct a similar or more complicated new problem based on an original problem. The former is called as problem generation and the latter is as problem reformulation. The purpose of this study was to explore the co-relation between problem generation and problem reformulation, and the educational effectiveness of each problem posing. For this purpose, on the subject of 33 pre-service secondary school teachers, this study developed two types of problem posing activities. The one was executed as the procedures of [problem generation${\rightarrow}$solving a self-generated problem${\rightarrow}$reformulation of the problem], and the other was done as the procedures of [problem generation${\rightarrow}$solving the most often generated problem${\rightarrow}$reformulation of the problem]. The intent of the former activity was to lead students' maintaining the ability to deal with the problem generation and reformulation for themselves. Furthermore, through the latter one, they were led to have peers' thinking patterns and typical tendency on problem generation and reformulation according to the instructor(the researcher)'s guidance. After these activities, the subject(33 pre-service teachers) was responded in the survey. The information on the survey is consisted of mathematical difficulties and interests, cognitive and affective domains, merits and demerits, and application to the instruction and assessment situations in math class. According to the results of this study, problem generation would be geared to understand mathematical concepts and also problem reformulation would enhance problem solving ability. And it is shown that accomplishing the second activity of problem posing be more efficient than doing the first activity in math class.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.12
• /
• pp.55-63
• /
• 2003

The traffic accident is the prerequisite of the traffic accident reconstruction. In this study, the traffic accident (forward collision) and traffic accident reconstruction (inverse collision) simulations are conducted to improve the quality and accuracy of the traffic accident reconstruction. The vehicle and tire models are used to simulate the trajectories for the post-impact motion of the vehicles after collision. The impact dynamic model applicable to the forward and inverse collision simulations is also provided. The accuracy of impact analysis for the vehicular collision depends on the accuracy of the coefficients of restitution and friction. The neural network is used to estimate these coefficients. The forward and inverse collision simulations for the multi-collisions are conducted. The new method fur the accident reconstruction is proposed to calculate the pre-impact velocities of the vehicles without using the trial and error process which requires the repeated calculations of the initial velocities until the forward collision simulation satisfies with the accident evidences. This method estimates the pre-impact velocities of the vehicles by analyzing the trajectories of the vehicles. The vehicle slides on a road surface not only under the skidding during an emergency braking but also under the steering. A vehicle over steering or cornering with excessive speed loses the traction and leaves tile yaw marks on the road surface. The new critical speed formula based on the vehicle dynamics is proposed to analyze the yaw marks and shows smaller errors than ones of the existing critical speed formula.

• Journal of Korean Society of Transportation
• /
• v.32 no.5
• /
• pp.503-512
• /
• 2014

In this paper, various tire blow-out force experiment data were collected and analyzed to obtain approximate values of related coefficients such as rolling resistance, self-aligning torque, cornering stiffness, and radial stiffness for the analysis of the motion of vehicles with tire blow-outs. These coefficients related to tire blow-outs were input into a vehicle accident analysis program to simulate and examine the effects of tire blow-outs. Various configurations and velocities of vehicle collisions without tire blow-outs were also used as reference to establish collision events of vehicle collisions with tire blow-outs. For the events, the simulation analysis was performed and collision characteristics were obtained. Consideration of tire blow-outs or damages suggested in this study will greatly contribute to more reliable vehicle accident reconstructions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.171-180
• /
• 2001

Collision accident reconstruction algorithm are developed based on the deformation shape and severity of a car body. At first, the body stiffness equation representing the force-deformation relationship is derived using finite element analysis for head on collision of two cars. The database of deformation shapes and energies is constructed for five different collision configurations; each configuration contains three velocity conditions. Deformation shapes are obtained using a curve fitting method and result in cubic polynomials. Deformation energies are calculated using a stiffness equation and deformation data. Three algorithms are developed to reconstruct collision configuration compared with constructed database. The developed algorithms show reasonably good performance to find collisions conditions for some test problems.

• Communications of Mathematical Education
• /
• v.12
• /
• pp.93-102
• /
• 2001

수학은 합리적이고 논리적으로 사고하는 양식(style)의 학문으로서 과학기술이 발전함에 따라 점진적으로 변화하고 확장되는 개념의 집합체이다. 불확실한 미래사회에 대비하기 위하여 문제해결, 추론 및 의사결정의 기법은 학교수학에서 더욱 강조되어야 한다. 이러한 사회환경의 변화에 적극적으로 대처하기 위하여 7차 교육과정의 기본 방향을 ‘자율적 ${\cdot}$ 창의적인한국인 육성’으로 설정한 교육부는 국민 공통 기본 교육과정의 수학을 ‘단계형 수준별 교육과정’으로 규정하고, 1학년에서 10학년까지를 20개의 소단계(1-가에서 10-나)로 세분하고 있다. 그러나 단계형 수준별 교육과정을 지나치게 의식하게 되면, 학생들의 개인차나 협동학습, 학습평가 등의 교수 ${\cdot}$ 학습의 여러 측면에서 자칫 혼란이 우려된다. 이에 본 연구에서는 수준별 교육과정을 운영하고 있는 뉴질랜드의 교육과정을 살펴보고, 학생들의 자율성과 창의성을 신장할 수 있는 방안으로서 교과서의 재구성 방안과 이에 따른 교사의 역할을 살펴보고자 한다.

• Journal of The Korean Association For Science Education
• /
• v.20 no.2
• /
• pp.329-343
• /
• 2000

The purpose of this study is to develop the middle school science curriculum to enhance creative problem-solving abilities. The reconstructed curriculum consisted of three big components, that is, scientific knowledge, process skills, and creative thinking skills. Five themes have been selected to incorporate with four areas of the middle school science curriculum, namely, physics, chemistry, biology, earth science. The five themes are structure, change, interaction, energy, and stability. Based upon these five themes, the individual or separated scientific knowledges of learners can be put into the unified knowledges. The process skills were observing, measuring, classifying, communicating, inferring, predicting, variable differentiating controling, data gathering analysis, establishing hypotheses, experiment design, and experimenting. Creative thinking skills include divergent and critical thinking. The finally developed curriculum is presented in the form of matrix.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.6
• /
• pp.615-622
• /
• 2015

Recently Digital-TachoGraph(DTG) was mounted mandatorily in commercial vehicles(Taxi, Bus, etc.). DTG records accurate and detailed information of the running state of vehicles related to traffic accident, such as Time, Distance, Velocity, RPM, Brake ON/OFF, GPS, Azimuth, Acceleration. Thus those standardized data can play an important role in traffic accident investigation and reconstruction. To develope the accurate and objective method using the DTG data for the reconstruction of traffic accident, we had conducted several tests such as driving test, high speed circuit test, braking test, slalom test at Korea Automobile Testing & Research Institute(KATRI), and collision test at Korea Automobile insurance repair Research and Training center(KART) with the vehicle equipped with several DTG. Development of the program which enables the reading and analysis of the DTG data was followed. In the experiments, we have found velocity error, RPM error, brake signal error and azimuth error in several products, and also non-continuous event data. The cause of these errors was deduced to be related to the correction factor, the durability of electronic parts and the algorithm.