• International Journal of Railway
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• v.6 no.3
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• pp.95-106
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• 2013

Earthborne vibrations are induced by construction operation such as pile driving, roadbed compaction, and blasting and also by transit activities such as truck and trains. The earthborne vibration creates the stress waves traveling outward from the source and can structurally damage nearby buildings and structures in the forms of direct damage to structure and damage due to dynamic settlement. The wave propagation characteristics depends on impact or vibration energy, distance from the source, and soil characteristics. The aim of this paper is to provide a comprehensive review on the mechanistic of earthborne vibration and the current practice of vibration control and mitigation measures. The paper describes the state of knowledge in the areas of: (1) mechanics of earthborne vibration, (2) damage mechanism by earthborne vibration, (3) calculation, prediction of ground vibration, (4) the criteria of vibration limits, (5) vibration mitigation measures and their performance, and (6) the current practice of vibration control and mitigation measures.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.622-632
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• 2004

We have studied how liquid crystal's rubbing direction and voltage driving method affect generation of disclination line. At first, generation of disclination line in vertical alignment(VA) cell and VA-twisted nematic(TN) cell has been examined. When liquid crystal's rubbing direction of bottom substrate was 0$^{\circ}$, the degree of generated disclination line was the smallest value. Further, the generation of disclination line above the electrode is less in the frame inversion than in the line inversion. Secondly, we have examined a generation of disclination line in reflective fringe-field switching cell. When the distance between common electrodes is over 3 ${\mu}{\textrm}{m}$ with on-state of one pixel and off-state of neighboring pixels, the reflectance appears only on-state pixel without generating reflectance in adjacent pixels.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.325-336
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• 2023

With the development of autonomous driving technology, the number of external contact sensors mounted on vehicles is increasing, and the importance is also rising. The vehicular ultrasonic sensor uses the LIN protocol in the form of a bus topology and reports a status message about its surroundings through the vehicle's internal network. Since ultrasonic sensors are vulnerable to various threats due to poor security protocols, physical testing on actual vehicle is needed. Therefore, this paper developed a LIN-CAN co-analysis testbed with a jig for location-specific distance test to examine the operational relation between LIN and CAN caused by ultrasonic sensors.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.221-222
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• 2023

The purpose of this study is to analyze the applicability and limitations of SPOT robots in the construction industry. The SPOT robot, which is being introduced to construction sites for smart construction with the progress of the 4th industrial revolution, is shaped like a four-legged dog and is equipped with various sensors for data collection and autonomous driving. In this study, hardware and software were analyzed, such as the size of the SPOT robot, mobility on slopes and heights, operating environment, and software functions that can collect data with a sensor weighing up to 14 kg. In addition, while the SPOT robot operates in a construction environment, performance such as stability, accuracy, signal connection distance, and obstacle avoidance are evaluated, and the applicability and limitations of the SPOT robot in the construction industry are analyzed. Based on this analysis, the purpose of this study is to evaluate when and how SPOT robots can be effectively used at construction sites, identify limitations, and derive contributions and improvements for the construction industry.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.47-53
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• 2017

There is a difficulty in preventing drunken driving by enforcing alcohol control on the sea due to the environment of Marine transportation rather than roads. In the previous study, we proposed the algorithm, that was developed to identify the voices changed according to be drunk. Using the developed algorithm, it became possible to know the possibility of drinking by long distance ship operators and crew members. In that method drinking can be measured in real time, no matter how far the distance is, if the interception is through a voice that can be transmitted over a distance, rather than a short distance. When communicating voice using the VTS wireless devices, clipping occurs when that environment is uneven, and the rate of judgment of the possibility of drinking may be lowered. Therefore, in this paper, we proposed an enhanced method to compensate the signal in order to reduce the error rate of the possibility of drinking due to distortion of the speech signal.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.944-956
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• 2013

Drivers need lots of information when they drive on the highway, however it is necessary and important to be provided information which is appropriate formation. In order to offer the suitable information, adequate size, quantity, and frequency of provided information are required for the drivers. To evaluate propriety of the expressed message of VMS that provides real-time traffic conditions, first of all, the amount of message about legibility distance and viewing should be estimated. In this research, drivers' characteristics of VMS message design were also reviewed to enhance the efficiency of VMS. And legibility distance, the amount of viewing information, and ratio of viewing information were analyzed on the currently operating VMS. The results of this study proposed that the appropriate size, quantity, and frequency were concluded by the legibility and memory of message on the real driving conditions. Consequently, these design methods of VMS could be expected to improve the transmitting capability of highway information to drivers.

• Journal of IKEEE
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• v.24 no.1
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• pp.232-237
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• 2020

In this paper, we propose an efficient sensor fusion method for autonomous vehicle recognition and distance measurement. Typical sensors used in autonomous vehicles are radar, lidar and camera. Among these, the lidar sensor is used to create a map around the vehicle. This has the disadvantage, however, of poor performance in weather conditions and the high cost of the sensor. In this paper, to compensate for these shortcomings, the distance is measured with a radar sensor that is relatively inexpensive and free of snow, rain and fog. The camera sensor with excellent object recognition rate is fused to measure object distance. The converged video is transmitted to a smartphone in real time through an IP server and can be used for an autonomous driving assistance system that determines the current vehicle situation from inside and outside.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.5
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• pp.71-78
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• 2010

Teachers have to measure the distance from their students' houses to neighboring schools manually by using ruler or driving cars every year. Not only it makes an significant overhead, but it also makes a problem of reliability of measured distance. The problem of fairness exists as well if measured distance is incorrect erroneously or deliberately. In this paper, we propose a scheme for constructing GIS and use its data for assigning students for entering middle schools without tests. We analyze the manually measured first and second nearest schools by using GIS data and confirm the measured distances have considerable errors. We also assign students based on the first and the second nearest school by using GIS. As a result, the distance to the assigned school reduced significantly and the fairness increases as well.

• Journal of the Korean Data and Information Science Society
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• v.24 no.2
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• pp.369-377
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• 2013

The purpose of this study was to explore which factors mostly influenced players' tour results employing tour skill factors provided by LPGA. For this study, Top 10 LPGA players' stats during 9 years (2004 2012) were used. As matter of fact, 10 variables were used like average score, top 10 finish, average putt, average birdies, average eagles, driving distance, driving accuracy, greens in regulation, sand saves, putts per GIR. and prize money earning. Stepwise multiple regression was conducted using SPSS win 20.0. Results indicated that the most influential tour skill factor to 9 seasons' results was average score, second influential factor was average putt, and the third factor was driving distance, and then top 10 finish was the fourth. Also on a year on year basis, 2004 was average score, 2005 was GIR., 2006 was average eagles, 2007 was top 10 finish, 2008 was average score, 2009 was average putt, 2010 were average score, GIR. and putt per GIR, 2011 was average birdies and 2012 was putt per GIR.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.227-235
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• 2011

At present, the characteristics of drivers are not properly considered when informations are provided via VMS even though the Variable Message Signs(VMS) are one of the key information provision medias on the roads. In this study, the driver's psychological response(stress index) was evaluated using a driving simulator for the position of the VMS provided, the contents of the VMS provided, the size of characters on VMS, and types of VMS expression. It was appeared that the stress is the least when the position of the VMS provided 1.5km proceeded from exit, the contents of the VMS provided are time information and types of VMS expression are character form respectively and the size of characters on VMS is appeared not important. In addition, the change of the users' satisfaction level was measured when increasing the numbers of VMS on unit distance and the size of characters. The size of character was almost not effected in similar to the result of stress index and the satisfaction level increased when increasing the number of VMS on the unit distance. The results of this research can be utilized as basic data for the ITS system design and operation stages.