• Journal of Auto-vehicle Safety Association
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• v.14 no.4
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• pp.35-42
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• 2022

This paper presents a stochastic model predictive control (SMPC) for stop maneuver of autonomous vehicles considering perception uncertainty of stopped vehicle. The vehicle longitudinal motion should achieve both driving comfortability and safety. The comfortable stop maneuver can be performed by mimicking acceleration profile of human driving pattern. In order to implement human-like stop motion, we propose a reference safe inter-distance and velocity model for the longitudinal control system. The SMPC is used to track the reference model which contains the position uncertainty of preceding vehicle as a chance constraint. We conduct simulation studies of deceleration scenarios against stopped vehicle in urban environment. The test results show that proposed SMPC can execute comfortable stop maneuver and guarantee safety simultaneously.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.320-328
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• 2021

As the number of visually impaired people steadily increases, interest in independent walking is also increasing. However, there are various inconveniences in the independent walking of the visually impaired at present, reducing the quality of life of the visually impaired. The white cane, which is an existing walking aid for the visually impaired, has difficulty in recognizing upper obstacles and obstacles outside the effective distance. In addition, it is inconvenient to cross the street because the sound signal to help the visually impaired cross the crosswalk is lacking or damaged. These factors make it difficult for the visually impaired to walk independently. Therefore, we propose the design of an embedded system that provides traffic light recognition through object recognition technology, voice guidance using TTS, and upper obstacle recognition through ultrasonic sensors so that blind people can realize safe and high-quality independent walking.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.51-58
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• 2009

In this paper, a system which uses Bluetooth and Zigbee wireless communication and mobile device is designed. The temperature within vehicle and the distance betweeen the vehicle and the obstacle is measured by ultrasonic sensor system. The measured data is sent to the mobile PDA and displayed to assist safe driving.

• ETRI Journal
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• v.45 no.2
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• pp.329-337
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• 2023

For safe last-mile autonomous robot delivery services in complex environments, rapid and accurate collision prediction and detection is vital. This study proposes a suitable neural network model that relies on multiple navigation sensors. A light detection and ranging technique is used to measure the relative distances to potential collision obstacles along the robot's path of motion, and an accelerometer is used to detect impacts. The proposed method tightly couples relative distance and acceleration time-series data in a complementary fashion to minimize errors. A long short-term memory, fully connected layer, and SoftMax function are integrated to train and classify the rapidly changing collision countermeasure state during robot motion. Simulation results show that the proposed method effectively performs collision prediction and detection for various obstacles.

• Explosives and Blasting
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• v.33 no.3
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• pp.29-50
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• 2015

Safe blast criteria based on the concept of scaled distances can be obtained from the statistical analysis on measured peak particle velocity data of blast vibrations. Two types of scaled distance widely used in Korea are the square root scaled distance (SRSD) and cube root scaled distance (CRSD). In contrast to SRSD scheme, however, the function of maximum charge per delay for CRSD increases without bound after the intersection point of these two functions despite of the similar goodness of fits. To prevent structural damage that may be caused by the excessive charge in the case of CRSD, it is suggested that CRSD be used within a specified distance slightly beyond the intersection point. On the other hand, there are several attempts that predict vibration level(VL) from the peak particle velocity(PPV) or estimate VL based on the scaled distances without considering their frequency spectra. It appears that these attempts are conducted in blasting contracts only for the purpose of satisfying the environment-related law, which mainly deals with the annoyance aspects of noises and vibrations in human life. But, in principle there could no correlation between peaks of velocity and acceleration over entire frequency spectrum. Therefore, such correlations or estimations should be conducted only between the waves with the same or very similar frequency spectra. Finally, it is a known fact that structural damage due to ground vibration is related to PPV level, the safety level criteria for structures should be defined by allowable PPV levels together with their zero crossing frequencies (ZCF).

• KIPS Transactions on Software and Data Engineering
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• v.10 no.2
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• pp.45-56
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• 2021

In platoon driving, several autonomous vehicles communicate to exchange information with each other and drive in a single cluster. The platooning technology has various advantages such as increasing road traffic, reducing energy consumption and pollutant emission by driving in short distance between vehicles. However, the short distance makes it more difficult to cope with an emergency accident, and accordingly, it is difficult to ensure the safety of platoon driving, which must be secured. In particular, the unexpected situation, i.e., variability that may appear during driving can adversely affect the safety of platoon driving. Because such variability is difficult to predict and reproduce, preparing safety guards to prevent risks arising from variability is a challenging work. In this paper, we studied a simulation method to avoid the risk due to the variability that may occur while platoon driving. In order to simulate safe platoon driving, we develop diverse scenarios considering the variability, design and apply safety guards to handle the variability, and extends the detail functions of VENTOS, an open source platooning simulator. Based on the simulation results, we have confirmed that the risks caused form the variability can be removed, and safe platoon driving is possible. We believe that our simulation approach will contribute to research and development to ensure safety in platoon driving.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.244-253
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• 2022

Recently, installation projects of structures such as offshore wind farms have been increasing, and the installation of such marine obstacles could affect ships that pass nearby. Therefore, the purpose of this study was to quantitatively evaluate the risk posed to passing ships due to obstacles in their passage. Hence, parameters that affected the risk were selected, and scenarios were set based on the parameters. The scenarios were evaluated through the ES model, which is a risk assessment model, and we confirmed that the risk ratio increased as the size of the obstacle increased, the safe distance from the obstacle increased, the speed of ship decreased, and the traffic volume increased. Additionally, we found that when the traffic flow direction was designated, the risk ratio was lower than that of general traffic flow. In this study, we proposed a generalization model based on the results of the performed scenarios, applied it to the Dadaepo offshore wind farm, and demonstrated that the estimation of the approximate risk ratio was possible through the generalization model. Finally, we judged that the generalization model proposed in this study could be used as a preliminary reference for the installation of marine obstacles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.121-132
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• 2008

Recently, there is a growing interest in promoting safe and convenient roadway and traffic conditions for elderly drivers. This paper analyzed the driving characteristics, self recognition, and any inconvenience of elderly drivers over age 65 through an extensive survey, and drew some action plans to improve the driving conditions for elderly drivers. Survey results showed that the major trip purposes of the elderly driver were found to be commuting(50%) and business(33%), and this pattern was similar to the general drivers. The elderly drivers are interested in "safety", but "brand recognition" was the more important factor for the general drivers in the process of vehicle selection. The elderly drivers had no technical skill difference in driving as compared to the general drivers, but they fully recognized the physical deterioration such as reaction time and sight distance. In addition, the elderly drivers had a tendency to feel psychological contraction as to high workload driving conditions, thus it was necessary to make safe driving conditions by improving the design elements of traffic control devices on the roadways including visibility.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.472-484
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• 2012

Raised or plain block is widely used for the pedestrian's safe passage. The insincere construction, insufficient maintenance and obstacle overlaid on the pavement cause pedestrian's accidents. This paper proposes a method to detect brick path by analyzing the shape pattern and texture feature of brick located in visible distance for a safe passage. A brick appears to a regular type because of its specific shape which repeats with its sized gap and its type varies according to the surrounding environment or use. This paper shows a method which extracts the shape pattern by analyzing single surface polygon and its frequency appearing in road area. The shape pattern is used to detect similar shape regions. Some regions are not detected because extraneous substances or chopped bricks distort the original shape. This problem can be solved by analyzing the texture feature vector. The analyzed vector of the previously detected regions yields the Gaussian distribution. This value in each undetected region is computed and checked whether it's satisfied with Gaussian distribution or not. The satisfied region is detected as the brick path. The experiment was performed with the various type's bricks to recognize so that the results showed as accurate as 95.9% in average.

• The Korean Journal of Pain
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• v.23 no.1
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• pp.11-17
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• 2010

Background: The target of lumbar sympathetic ganglion block is the anterolateral surface of the L2, 3 and 4 vertebral bodies, where the lumbar sympathetic ganglion usually lies. In most cases, a block-needle is inserted approximately 5-8 cm lateral to spinous process on the skin and directed to the anterolateral surface of vertebral body obliquely. The purpose of this study is to determine the safe entry angle and entry point in Korean by using the abdominal CT scan images. Methods: The abdominal CT images of eighty five patients were recruited to this study. The minimal angle aimed at the lumbar sympathetic ganglion that can pass through the lateral aspect of body and maximal angle that avoids puncturing the kidney, ureter or retroperitoneal space were measured. The distance from midline to skin entry point was also measured. Results: There was no significant difference in entry angle among L2, 3, and 4 level. The entry angle was similar in the right and left side, and in males and females. The entry angle of old age group was significantly smaller than that of young age group. The calculated safe entry angle was $30.5{\pm}0.4^{\circ}$ and entry point was $7.7{\pm}0.2\;cm$ and $6.7{\pm}0.1\;cm$ lateral from midline in males and females respectively. Conclusions: These measurements can be used as a reference for lumbar sympathetic ganglion block and radiofrequency lesioning. Prior to performing the lumbar sympathetic ganglion block for cancer patients, the abdominal CT scan should be reviewed to prevent complications.