Journal of the Korean Society for Precision Engineering

A Highway Secondary Accident Prevention System based on FFT Analysis of Vehicle Collision Sounds: Minki Jung, Young Shin Cho, Yongsik Ham, Joong Bae Kim; J. Korean Soc. Precis. Eng. 2025;42(9):749-756.
Published online September 1, 2025; DOI: https://doi.org/10.7736/JKSPE.025.037

Abstract
PDF

This study introduces a highway secondary accident prevention system that employs Fast Fourier Transform (FFT) analysis of vehicle collision sounds. The system is designed to identify abnormal acoustic patterns produced during collisions and skidding events, enabling faster and more accurate accident detection than traditional methods. When a crash is detected, visual warning signals are instantly sent to nearby vehicles using LED devices powered by a photovoltaic panel and an energy storage system (ESS). Experimental results showed 100% detection accuracy during independent playback of collision, skidding, and driving sounds, and 80% accuracy during simultaneous playback. These results confirm the system's ability to effectively differentiate accident-related sounds and deliver timely alerts. This research offers an innovative and environmentally sustainable approach to enhancing highway safety and reducing the societal and economic consequences of secondary accidents.

11 View
0 Download

Development of Robotic Fiber Positioner and Path Planning Algorithm for Multi-object Spectroscopy: Hyunho Lim, Jae-Woo Kim, Ho Seong Hwang, Sungwook Hong, Jong Chul Lee, Young-Man Choi; J. Korean Soc. Precis. Eng. 2025;42(1):79-88.
Published online January 1, 2025; DOI: https://doi.org/10.7736/JKSPE.024.120

Abstract
PDF

A robotic focal plane system using robotic fiber positioners enables multi-object spectroscopy for hundreds to thousands of galaxies by utilizing a dense array of positioners that are closely packed at the focal plane of a telescope. While this dense arrangement increases the number of observations, it also introduces the potential for collisions between adjacent positioners. A fiber positioner is designed similarly to a SCARA robot. It is driven by two series of BLDC motors. Each positioner is manufactured with an outer diameter of 16 mm. It operates within an annular workspace with an outer diameter of 33.6 mm and an inner diameter of 12.8 mm. As these positioners are arranged with a spacing of 16.8 mm, target assignment and motion planning are critical to avoid collisions caused by overlapping workspaces. To address this, we proposed an optimized step choice algorithm using a motion planning method based on optimization with the sequential quadratic programming algorithm. Simulation results demonstrated that paths for all positioners within a tile were successfully generated with a success rate of up to 93.75% across 80 tiles.

6 View
0 Download

Periodicity of Droplet Impact Behavior by Liquid Viscosity on PDMS Surface: Dong Kwan Kang, Sangmin Lee; J. Korean Soc. Precis. Eng. 2022;39(11):857-862.
Published online November 1, 2022; DOI: https://doi.org/10.7736/JKSPE.022.070

Abstract
PDF

Periodicity behavior was observed after droplet collision in viscous solutions with controlled glycerol concentrations onto a PDMS surface. No periodic movement was observed in the droplets at glycerol concentrations of 50% or more. In contrast, the vertical diameter of the droplets increased and decreased periodically at glycerol solution concentrations of 40% or less. Moreover, there was little change in the periodicity of the impacting droplet movement, and the vibration frequency was measured at approximately 80 to 98 Hz in the entire range. The maximum droplet spreading factor after collision decreased significantly with increasing glycerol concentrations of 40% or more (Ohnesorge number 1.4 × 10^-2 or more). The results suggest that the effect of viscosity became greater than that of the solution surface tension with increasing glycerol concentrations.

Citations

Citations to this article as recorded by

Study of Droplet Characteristics of Electrospray Coating Method as a Function of Ring Electrode Parameters
Ji Yeop Kim, Mun Hee Lee, Jun Yeop Kim, Jung Goo Hong
Journal of the Korean Society for Precision Engineering.2024; 41(2): 153. CrossRef

8 View
0 Download
Crossref

2-D Topology Optimization of the Connection Part of the Electric Kickboard in Case of Front Collision: Min Gyu Kim, Ji Sun Kim, Jung Jin Kim; J. Korean Soc. Precis. Eng. 2022;39(11):841-848.
Published online November 1, 2022; DOI: https://doi.org/10.7736/JKSPE.022.068

Abstract
PDF

Electric kickboards provide personal mobility with a simple structure and easy operation. With these advantages, the number of users is increasing annually. However, as the number of users of electric kickboards increases, related accidents are also increasing. To prevent accidents, this study proposes the topological optimization of an electric kickboard connecting part to improve structural strength during a front collision. The results confirmed that as the volume fraction increased, the structure connecting the board and the bottom of the handle support changed to a toroidal shape, thereby lowering the maximum stress and improving the uniformity of the stress distribution. In addition, the topological optimization was safer than the connecting parts of two typical electric kickboards sold in the Korean market. These findings can contribute to improving the safety and optimizing the design direction of electric kickboards.

Citations

Citations to this article as recorded by

Two-Dimensional Topology Optimization of Headtube in Electric Scooter Considering Multiple Loads
Min Gyu Kim, Jun Won Choi, Jung Jin Kim
Applied Sciences.2025; 15(5): 2829. CrossRef
Personalized Stem Length Optimization in Hip Replacement: A Microscopic Perspective on Bone—Implant Interaction
Su Min Kim, Jun Won Choi, Jung Jin Kim
Bioengineering.2024; 11(11): 1074. CrossRef

10 View
0 Download
Crossref

Impact Safety Prediction of Automotive Reinforcement Seat Belt Parts for 590 MPa Grade Materials by Using Computer Simulation: Kee Joo Kim, Jae-Woong Lee; J. Korean Soc. Precis. Eng. 2022;39(7):529-535.
Published online July 1, 2022; DOI: https://doi.org/10.7736/JKSPE.022.035

Abstract
PDF

High-strength steel, which has higher strength than ordinary steel, has emerged as a representative lightweight material because of its superior price competitiveness and easy application of manufacturing processes compared to other lightweight materials such as nonferrous metals and sandwich plates. Thus, the purpose of this study was to reduce the thickness and light weight of parts by applying high strength steel more than 600 MPa to various body parts. TR590 and DP590 high tensile steels were applied to the reinforcement seat belt front top and bottom components respectively. To this end, the impact simulation was performed, and the safety of the parts was investigated through FE-Analysis. Prototype molding evaluation confirmed the possibility of mass production of reinforcement seat belt front upper and lower components, using high tensile steel.

5 View
0 Download

Driver Behavior Simulation considering Crash Condition of an Automated Vehicle: Moon Young Kim, Jangu Lee, Jayil Jeong; J. Korean Soc. Precis. Eng. 2022;39(3):187-192.
Published online March 1, 2022; DOI: https://doi.org/10.7736/JKSPE.021.122

Abstract
PDF

In this study, the behavior of the driver was derived by conducting a crash simulation considering automated vehicle accident conditions using autonomous emergency braking (AEB) and a human body model (HBM). Based on car-to-car intersection accident conditions in the OSCCAR project and the actual accident report, a crash accident case was selected. The base crash scenario was reconstructed by conducting a driving simulation with reference to the selected accident cases. Additional simulations applying AEB are performed. Based on the boundary conditions, a car-to-car crash simulation was performed to derive a crash pulse. This crash pulse and HBM were applied to a simple cabin model for conducting driver behavior analysis. The results confirmed that the head behavior of the driver of the opposing vehicle increased in the lateral direction.

Citations

Citations to this article as recorded by

Vehicle-motion-based Front Wheel Steer Angle Estimation for Steer-by-Wire System Fault Tolerance
Seungyong Choi, Wanki Cho, Seung-Han You
Journal of the Korean Society for Precision Engineering.2024; 41(5): 347. CrossRef

6 View
0 Download
Crossref

A Study on the Plastic Deformation by Collision of a Safety Coupling under Overload: Hyeon Jun Jung, Taek Jin Jang, Byung Ro Kim, Sungmuk Kim, Jong-Bong Kim; J. Korean Soc. Precis. Eng. 2021;38(3):187-193.
Published online March 1, 2021; DOI: https://doi.org/10.7736/JKSPE.020.101

Abstract
PDF

Plastic deformation of balls in safety coupling by collision with V-Hole was investigated in the current study. Generally, when the applied torque is greater than the maximum allowable torque, balls in V-Hole get out from the holes and the coupling loses the torque transfer capability. After balls are out from the V-Holes, the balls and V-Hole rotate at a different velocity. When balls meet the next V-Hole, they collide into the wall of the V-Hole. Due to this collision, plastic deformation and wear take place. The plastic deformation and wear may reduce the torque transfer capability of the safety coupling. The reduction in torque transfer capability was observed in the experiment. In this study, plastic deformation of balls and flange was investigated through dynamic analysis of the safety coupling. Also, the effect of relative rotational velocity on the plastic deformation was investigated.

5 View
0 Download

Characterisation of Crash Behavior and Injury for Wheelchair User in Train during Accidental Collision: Seok Woo Ham, Gyeong Seok Kim, Seong Sik Cheon; J. Korean Soc. Precis. Eng. 2019;36(7):631-635.
Published online July 1, 2019; DOI: https://doi.org/10.7736/KSPE.2019.36.7.631

Abstract
PDF

Crash analyses was carried out to characterize crash behavior and injury of a wheelchair user in a train during collision based on SAFETRAIN PROJECT and AV/ST 9001, train safety regulations. There is no restraint system such as seat belt or air-bag in train, a wheelchair user is normally injured by bumping against wall. Crash behavior and injury of a wheelchair user was evaluated with respect to the distance (Dw) of the wheelchair from the wall and the wall foam thickness (tF). Additional crash analysis for a wheelchair user with seat belt was also performed in order to check the significance of the seat belt effect during crash.

6 View
0 Download

Design of Subminiaturized Natural Fragment Warhead based on the Analysis of Warhead Effectiveness: Joo Hyun Baek, Seoung Pil Lee, Young Joon Lee, Sung Un Kim; J. Korean Soc. Precis. Eng. 2018;35(10):933-941.
Published online October 1, 2018; DOI: https://doi.org/10.7736/KSPE.2018.35.10.933

Abstract
PDF

The design of subminiaturized natural fragment warhead is based on the analysis of its effectiveness against target personnel. Toward this end, the personnel incapacitation probability suggested by Sperrazza and Kokinakis was used. The effectiveness of various natural fragment warhead designs was analyzed by altering the fragment mass, velocity, number, and the target distance. A preliminary optimal design value of the natural fragment warhead in a subminiaturized missile was suggested, which was greater than the threshold value of the fragment mass to cope with air resistance. We also determined that the appropriate fragment mass was about 2.1204 × 10^-4 kg (3.3 grain) in case of a subminiature warhead. This work facilitates the development of final optimal design stage of the natural fragment warhead in a subminiaturized missile and can also be utilized for the analysis and design of different types of fragment warhead.

Citations

Citations to this article as recorded by

Analysis Method based on Probability Equation and Analysis Method based on Test in order to Estimate the Target Incapacitation Distance of Fragmentation Warhead
Joo Hyun Baek, Young Hwan Jo, Byung Uk Lee, Gu Hyun Ryu
Journal of the Korean Society for Precision Engineering.2020; 37(10): 751. CrossRef
Determination Method of Main Warhead Detonation Delay Time based on the Analysis about the Protection Capability of Target and the Scattering Behavior of Explosive Reactive Armor
Joo Hyun Baek, Se Lin Yu, Geun Jong Jeon, Won Young Lee, Young Hwan Jo, Byung Uk Lee
Journal of the Korean Society for Precision Engineering.2019; 36(10): 937. CrossRef

10 View
0 Download
Crossref

Shaping of Micro Scale Features on Metallic Surfaces through the High-Speed Impact of Laser Accelerated Flyers: Dae Cheol Choi, Hong Seok Kim; J. Korean Soc. Precis. Eng. 2018;35(7):729-734.
Published online July 1, 2018; DOI: https://doi.org/10.7736/KSPE.2018.35.7.729

Abstract
PDF

Generally speaking, the high speed forming process is suitable for the precise manufacturing of hard-to-form and high strength materials. This study conducted microscale embossing and punching experiments by establishing a forming system that uses a laser induced acceleration. The changes in the flyer velocity with the laser energy, flyer thickness, and flyer diameter were measured using a high speed camera, and the effects of the noted acceleration characteristics of flyers on processing performance were investigated. It is particularly important that in the case of punching, the advantages of high speed processing, in which the accuracy was improved by increasing the shear zone of the workpiece, were identified. Significantly in the case of embossing, it was observed that the formability improved by increasing the flyer velocity as the flyer diameter decreased. However, in the case when the flyer thickness was decreased, increased energy was consumed in the plastic deformation of the flyer, and the advantages of high speed forming could not be realized. For this reason, further research is needed to take advantage and optimize the forming process using the laser induced acceleration through experiments which are noted as considering the various process variables and materials.

Citations

Citations to this article as recorded by

Performance evaluation of laser shock micro-patterning process on aluminum surface with various process parameters and loading schemes
Dae Cheol Choi, Hong Seok Kim
Optics and Lasers in Engineering.2020; 124: 105799. CrossRef

6 View
0 Download
Crossref

The Solution of Peening Residual Stress by Angled Impact of Multi Elliptical Shot Ball Based on Finite Element Analysis: Taehyung Kim; J. Korean Soc. Precis. Eng. 2017;34(2):151-156.
Published online February 1, 2017; DOI: https://doi.org/10.7736/KSPE.2017.34.2.151

Abstract
PDF

Shot peening is widely used to improve the fatigue life and strength of various mechanical parts and an accurate method is important for the prediction of the compressive residual stress caused by this process. A finite element (FE) model with an elliptical multi-shot is suggested for random-angled impacts. Solutions for compressive residual stress using this model and a normal random vertical-impact one with a spherical multi-shot are obtained and compared. The elliptical multi-shot experimental solution is closer to an X-ray diffraction (XRD) than the spherical one. The FE model’s peening coverage also almost reaches the experimental one. The effectiveness of the model based on an elliptical shot ball is confirmed by these results and it can be used instead of previous FE models to evaluate the compressive residual stress produced on the surface of metal by shot peening in various industries.

Citations

Citations to this article as recorded by

The Effect of Micro-Peening to Improve the Fatigue Characteristic of Reduction Gear of Manned and Unmanned Aircraft
Taehyung Kim, Jin Woon Seol, Seok Haeng Huh, Joo Hyun Baek
Journal of the Korean Society for Precision Engineering.2017; 34(9): 603. CrossRef