• International Journal of Automotive Technology
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• v.7 no.5
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• pp.603-608
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• 2006

As an important and relatively easy to implement technology for realizing Intelligent Transportation Systems(ITS), Adaptive Cruise Control(ACC) automatically adjusts vehicle speed and distance to a preceding vehicle, thus enhancing driver comfort and safety. One of the key issues associated with ACC development is usability and user acceptance. Control parameters in ACC should be optimized in such a way that the system does not conflict with driving behavior of the driver and further that the driver feels comfortable with ACC. A driving simulator is a comprehensive research tool that can be applied to various human factor studies and vehicle system development in a safe and controlled environment. This study investigated driving behavior with ACC for drivers with different driving styles using the driving simulator. The ACC simulation system was implemented on the simulator and its performance was evaluated first. The Driving Style Questionnaire(DSQ) was used to classify the driving styles of the drivers in the simulator experiment. The experiment results show that, when driving with ACC, preferred headway-time was 1.5 seconds regardless of the driving styles, implying consistency in driving speed and safe distance. However, the lane keeping ability reduced, showing the larger deviation in vehicle lateral position and larger head and eye movement. It is suggested that integration of ACC and lateral control can enhance driver safety and comfort even further.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.639-643
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• 2003

The emphasis is put on the detailed knowledge on manoeuvring characteristic for the safe navigation while avoiding terrible collision between ships and on the guideline to the design and operation of the ship-waterway system The numerical simulation of manoeuvring motion was carried out parametrically for different ship types, ship-velocity ratios, separation and stagger between ships. As for the calculation parameters, the ratios of velocity difference (hereafter, $U_2$/$U_1$ ) between two ships were considered as 0.6, 1.2, 1.5. From the inspection of this investigation, it indicates the following result. Considering the interaction force only as parameter, the lateral distance between ships is necessarily required for the ship-velocity ratio of 1.2, compared to the cases of 0.6 and 1.5 regardless of the ship types. Furthermore, regardless of the ship-velocity ratio, an overtaking and overtaken vessel can be manoeuvred safely without deviating from the original course under the following conditions: the lateral distance between two vessels is approximately kept at 0.5 times of ship-length and 5 through 10. degrees of range in maximum rudder angle. The manoeuvring characteristic based on this investigation will be very useful for keeping the safety of navigation from the practical point of ships design and traffic control in restricted waterways.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.401-407
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• 2012

The recent manufacturing process in the thin wafers and flat panel necessitate new approaches to reduce handling fragile and surface-sensitive damage of components. This paper presents a new pneumatic levitation for non-contact handling of parts and substrates. This levitation can achieve non-contact handling by blowing air into an air pressure pick-up head with radial passages to generate a negative pressure region. Negative pressure is caused by the radial air flow by nozzle throat and through holes connecting to the bottom region. The numerical analysis deals with the levitational motion with different design factors. The dynamic motion is examined in terms of force balance(dynamic equilibrium) occurring to the flow field between two objects. The stable equilibrium position and the safe separation distance are determined by analyzing the local pressure distribution in the fluid motion. They make considerable design factors consisting the air pressure pick-up head. As a result, in case that the safe separation distance is beyond 0.7mm, the proposed pick-up head can levitate stably at the equilibrium position. Furthermore, it can provide little effect of torque, and obtain more wide picking region according to the head size.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.218-223
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• 2009

During the process of excavation for substructures of buildings, precise and constant measurements of retaining wall displacement is crucial for construction to be complete and safe. Currently an inclinometer is used to measure displacement around the perimeter of an excavation site. The existing inclinometer system requires an instrument to be placed inside pre-bored holes for each measurement with an typical interval of two weeks. This makes it difficult to obtain continuous displacement data, especially during a critical time such as rainy season in summer. Also, the existing inclinometer is placed at certain distance away from the retaining wall system itself. Thus, exact measurement of retaining wall movement is compromised because of the distance between the retaining wall and the inclinometer. This paper presents the development of wireless inclinometer system for the displacement measurement of retaining walls by being attached directly to the retaining wall. The result of the application of the developed systems are provided with advanced ubiquitous sensor network (USN) system features. The USN technique incorporated into the system enables users to monitor movement data from wherever possible and convenient such as construction manager's office on site or any other places connected through internet. The research work presented in this paper will provide a basis to save construction time and cost by preventing safe-related unexpected delay of construction due to the failure or collapse of retaining walls.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.47-56
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• 2022

The safe driving reward system aims to reduce the loss of life and property by reducing the occurrence of accidents by motivating safe driving and encouraging active participation by providing direct reward to vehicle drivers who have performed safe driving. In the case of the existing digital tachograph, the goal is to limit dangerous driving by recording the driving status of the vehicle whereas the safe driving reward system is a support measure to increase the effect of accident prevention and induces safe driving with financial reward when safe driving is performed. In other words, in an area where accidents due to speeding are high, direct reward is provided to motivate safe driving to prevent traffic accidents when safe driving instructions such as speed compliance, maintaining distance between vehicles, and driving in designated lanes are performed. Since these safe operation data and reward histories must be managed transparently and safely, the reward evidences and histories were constructed using the closed blockchain Hyperledger Fabric. However, while transparency and safety are guaranteed in the blockchain system, low data processing speed is a problem. In this study, the sequential block generation speed was as low as 10 TPS(transaction per second), and as a result of applying the acceleration function a high-performance network of 1,000 TPS or more was implemented.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.273-278
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• 2002

Modern society is an interaction between many different environments. It is important to the mutual relationships between people and especially between people and the environment. One of the mutual relationships between people and the environment is the traffic system, especially the traffic signals which give priority to pedestrian and traffic flow. Traffic signals for the pedestrian on the crosswalk contribute to a safe road environment for the pedestrian, while the traffic signals for the pedestrian running for the flickering of the green signal causes psychological stress. Therefore, this study investigated whether the walking velocity was influenced by the flickering of the green signal or not. Also, this study investigated whether the walking distance had an effect on the walking velocity of the elderly pedestrian or not. It was proved that the flickering of the green signal and the walking distance influenced the walking velocity and subjective sensitiveness according to the result of this study.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.309-316
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• 2017

In shuttle vans designed to transport children, the recognition of a child's approach and departure is very important. Ultrasonic sensors are generally used for a short distance around a vehicle. Although ultrasonic sensors are cheaper than other ADAS sensors, the number of sensors installed in a van should be optimized. In order to recognize the presence of a child around a shuttle van, this paper proposes the placement of ultrasonic sensors in the van. Considering the turning radius of the van and the distance from each sensor to a child, collision risk is classified as 'safe', 'warning', and 'danger'. The sensor placement and the recognition algorithm are verified in a virtual driving environment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.3
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• pp.196-202
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• 2003

Two dimensional modeling was carried out to find the safety distance between the defrost heater and the plastic inner wall of domestic refrigerator Estimation was processed for the three cases; the estimation of plastic wall temperature (1) without any protection, (2) with an aluminum foil attached on a wall, and (3) with an aluminum shield installed between heater and wall. The former two cases are found to be dangerous during defrosting process, because the temperatures of inner wall reach above 80'C , which is the upper temperature limit of the wall material. The case with an aluminum shield is considered to be safe by maintaining the temperature of the wall in the range of 6$0^{\circ}C$ during defrosting process.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.425-429
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• 1987

This paper describes a collision avoidance method for planning safe trajectories for multi-robot system in common work space. Usually objects have been approximated to convex polyhedra in most previous researches, but in case using such the approximation method it is difficult to represent objects analytically in terms of functions and also to describe tile relationship between the objects. In this paper, in order to solve such problems a modeling method which approximates objects to cylinder ended by hemispheres and or sphere is used and the maximum distance functions is defined which call be calculated simply. Using an objective function with inequality constraints which are related to minimum distance functions, work range and maximum allowable angular velocities of the robots, tile collision avoidance for two robots is formulated to a constrained function optimization problem. With a view to solve tile problem a penalty function having simple form is defined and used. A simple numerical example involving two PUMA-type robots is described.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.206-213
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• 2002

This paper proposes a vehicle trajectory prediction method for application to vehicle-to-vehicle distance control. This method is based on 2-dimensional kinematics and a Kalman filter has been used to estimate acceleration of the object vehicle. The simulation results using the proposed control method show that the relative distance characteristics can be improved via the trajectory prediction method compared to the customary vehicle stop and go cruise control systems which makes the vehicle remain at a safe distance from a preceding vehicle according to the driver's preference, automatically slow down and come to a full stop behind a preceding vehicle.