• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.241-254
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• 2002

Though there are many kinds of type in the expansion joint of bridges, Transflex joint was usually used from 1970's to 1980's. But it made of rubber is needed to exchange to new one often because of the breakage by wheel load. This study performed the safety estimation which is to exchange the transflex joint to finger joint kept the part of situ-cast-concrete. The standard of finger joint is same as that of transflex joint, we investigated the safety of finger joint with experimental results and FEM (Finite element method) analysis.

• Journal of Auto-vehicle Safety Association
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• v.13 no.4
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• pp.123-128
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• 2021

This paper present box feature estimation from LiDAR point cluster using maximum likelihood Method. Previous LiDAR tracking method for autonomous driving shows high accuracy about velocity and heading of point cluster. However, Assuming the average position of a point cluster as the vehicle position has a lower accuracy than ground truth. Therefore, the box feature estimation algorithm to improve position accuracy of autonomous driving perception consists of two procedures. Firstly, proposed algorithm calculates vehicle candidate position based on relative position of point cluster. Secondly, to reflect the features of the point cluster in estimation, the likelihood of the particle scattered around the candidate position is used. The proposed estimation method has been implemented in robot operating system (ROS) environment, and investigated via simulation and actual vehicle test. The test result show that proposed cluster position estimation enhances perception and path planning performance in autonomous driving.

• Proceedings of the Safety Management and Science Conference
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• 2012.11a
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• pp.461-471
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• 2012

Most useful statistical techniques in six sigma DMAIC are hypothesis testing and interval estimation. So this paper reviews and derives sample size formula by considering significance level, power of detectability and effect difference. The quality practioners can effectively interpret the practical and statistical significance with the rational sample sizing.

• Journal of the Korean Society of Safety
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• v.26 no.1
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• pp.43-48
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• 2011

Estimation of accident costs would set a sound criterion on which invest judgement for work improvement would be decided. Unfortunately, however, the professional agency and most companies in Korea still adopt the conventional cost estimation method based on Heinrich's theory would not be applicable any more since it was developed about a century ago. This research was carried out to confirm the validity of conventional accident cost estimation method. With 110 accident cases occurred in an autoglass manufacturing plant for last 7 years, post-accident treatment procedure was simplified as a model with several phases, and practical costs were analyzed case by case. The results showed that, as expected, the company should the largest portion of loss due to accidents, and that mean indirect cost were 10.10(${\pm}20.70$) times as much as direct cost estimated by conventional method. Therefore, finally, accident types and items influenced much on accidents costs were analyzed and discussed.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.149-156
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• 2003

The estimation of fatigue limit for the component with complicated shape is difficult than of standard fatigue specimen, due to complex test equipment. So, we substitute maximum principle stress from FEM results for fatigue limit diagram made by standard fatigue specimen. Then we can estimate endurance safety of component with high trust. The static stress analysis, the nonlinear contact stress analysis and the model analysis for turbine blade is performed by ANSYS ver. 5.6. the comparison of maximum static stress around hole with maximum contact stress between pun and hole can make the cause of fracture for turbine blade clear. The difference of fatigue limit between fatigue test by standard specimen and in-service mechanical components is due to surface roughness and machining condition etc. In in-service mechanical components, Goodman diagram has to consider surface roughness for failure analysis. To find fracture mechanism of torison-mounted blade in nuclear plant. This study performs the static stress, the nonlinear contact stress and the modal analysis on torison-mounted blade with finite element method and makes the estimation for safety of turbine blade.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.33 no.12
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• pp.11-18
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• 2017

The safety inspection cost of the construction work was based on commercial facilities classified as a single building. Therefore, it is not possible to fully reflect the characteristics of the multi-building construction project such as apartment houses. Therefore, this study suggests a reasonable estimation model that can fully reflect the characteristics of the multi-building construction project. The safety inspection cost estimation model proposed two models such as construction cost ratio method and cost plus fixed fee method. And these models were simulated by the apartment construction work and compared with the current standard. As a result, the current construction cost ratio method has shown that the safety inspection cost tends to be overestimated as the construction size increases. Therefore, the proposed model has reflected characteristics of the multi-building construction project, so that it can reasonably estimate the safety inspection cost more than the current standard.

• Journal of Drive and Control
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• v.14 no.3
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• pp.40-49
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• 2017

This study presents an online estimation of an excavator's rotational inertia by using recursive least square with forgetting. It is difficult to measure rotational inertia in real systems. Against this background, online estimation of rotational inertia is essential for improving safety and automation of construction equipment such as excavators because changes in inertial parameter impact dynamic characteristics. Regarding an excavator, rotational inertia for swing motion may change significantly according to working posture and digging conditions. Hence, rotational inertia estimation by predicting swing motion is critical for enhancing working safety and automation. Swing velocity and damping coefficient were used for rotational inertia estimation in this study. Updating rules are proposed for enhancing convergence performance by using the damping coefficient and forgetting factors. The proposed estimation algorithm uses three forgetting factors to estimate time-varying rotational inertia, damping coefficient, and torque with different variation rates. Rotational inertia in a typical working scenario was considered for reasonable performance evaluation. Three simulations were conducted by considering several digging conditions. Presented estimation results reveal the proposed estimation scheme is effective for estimating varying rotational inertia of the excavator.

• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.71-76
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• 2007

Failures of equipments for train control systems are linked directly to extensive damages of human lives or financial losses from the increasing uses of train control equipments utilizing computers. Then safety activities for assuring safety and reliability are needed during the system life-cycle. Risk analysis is important phase to increase safety from determining the risk presented by the identified hazard. In this paper, we investigated several methods for risk estimation of safety activities, and then we drew a comparison between original methods to suggest optimized one in the application to train control systems. In the result of the comparison, we had plan to propose the risk analysis method called Best-Practice(BP) risk method combining advantages of the qualitative and the quantitative analysis. In addition, we attempted to apply the BP-risk method to domestic train control systems handling in Korea.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.621-626
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• 2015

This paper presents a camera calibration method in order to estimate the lane detection and inter-vehicle distance estimation system for an automotive safety driving system. In order to implement the lane detection and vision-based inter-vehicle distance estimation to the embedded navigations or black box systems, it is necessary to consider the computation time and algorithm complexity. The process of camera calibration estimates the horizon, the position of the car's hood and the lane width for extraction of region of interest (ROI) from input image sequences. The precision of the calibration method is very important to the lane detection and inter-vehicle distance estimation. The proposed calibration method consists of three main steps: 1) horizon area determination; 2) estimation of the car's hood area; and 3) estimation of initial lane width. Various experimental results show the effectiveness of the proposed method.

• Journal of Auto-vehicle Safety Association
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• v.3 no.2
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• pp.28-33
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• 2011

This paper presents driving path estimation algorithm for adaptive cruise control system and advanced emergency braking system using multi-sensor fusion. Through data collection, yaw rate filtering based road curvature and vision sensor road curvature characteristics are analyzed. Yaw rate filtering based road curvature and vision sensor road curvature are fused into the one curvature by weighting factor which are considering characteristics of each curvature data. The proposed driving path estimation algorithm has been investigated via simulation performed on a vehicle package Carsim and Matlab/Simulink. It has been shown via simulation that the proposed driving path estimation algorithm improves primary target detection rate.