• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.366-370
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• 2014

Considering a countermeasure against vibration along the existing line, in many cases, it may be the most efficient method to replace existing fasteners with high resilient fasteners because of the restriction of the construction of a new track type. There are many types of high resilient fasteners which are different in price and performance. Therefore it is important to choose the high resilient fastener which has best vibration-proof performance per price. In this study, a prediction method which can exactly evaluate the performance of a fastener in the reduction the ground borne noise in the existing line is presented, which is constructed based on the combination of the measurement and the simulation. A numerical example using the presented method is introduced to evaluate the vibration-proof performance for the solution of the vibration problem in the existing line.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.12
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• pp.113-118
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• 2011

In this study, investigation and appraisal method for the scene of a fire according to electrical fire hazards of hair dryer which is usually used at living space are presented. Hair dryer is briefly composed of heating part, wind part and control part. Electrical fire hazards of hair dryer are insulation destruction of power cord, ignition by overheat of heating coil, scattering spark on inside dust, overheat of motor by fan shackle, ignition by carelessness of user, and so on. Fire cause by hair dryer can be perceived through investigation about half-disconnection of power cord, contact badness of power plug, verification of heating coil, fan and switch. These results are expected to be utilized effectively in a countermeasure to prevent an electrical fire by hair dryer.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.6
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• pp.96-108
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• 2003

Agricultural water occupies the largest portion of total water use in Korea, and generally researches on the development of agricultural water have been stressed on the demand of agricultural water itself. But it is unavoidable to change a policy from the development of water resources to cope with the increase of water demand to the effective management of existing water resources. Evaluation of the decrepitude of irrigation facilities and their reasonable maintenance are important for the effective supply and use of agricultural water. Therefore it is necessary to develop evaluation technique that diagnoses the current condition of irrigation canals and suggest a countermeasure to improve the found problems. 25 items in 6 classes were selected for the evaluation of irrigation canal systems, and the weighted value between the items was calculated using AHP (Analysis Hierarchy Process) method. The current condition of the irrigation facilities was evaluated from the class evaluation marks, and ranking was decided from the total marks between the projects, and finally the priority of the project for the improvement was given.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.318-323
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• 2003

In order to polish complicated shaped inner surfaces of molds, a new polishing method with consolation liquid was Invented The MAGIC (MAGnetic Intelligent Compound) Polishing is the best method, a countermeasure of polishing trouble that is reduce of productivity and instability of quality. But because MAGIC polishing is new polishing method there is no study of the standardization of polishing by MAGIC wheel yet. So we want to standadize MAGIC polishing condition. For the First time, we will evaluate the influence of composition ratio and kind of polishing grain in polishing surface roughness. In this study, we determined amount of dressing oil and dressing point as kind and composition ratio of polishing grain. we compared surface roughness case by case

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1303-1308
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• 2004

This paper proposes a reduction method for the mis-operation analysis of the DC High Speed Circuit Breaker(HSCB) in electric railway substation system. The analysis method is based on present condition of operation which is a method for accuracy level up. There is reason to operation of HSCB that it is mis-operation of fault detection relay(50F), operation of ground fault relay(64P), and trouble of electric car. A countermeasure is relay resetting through field test, induction of GTOCB(Gate Turn Off Thyristor Circuit Breaker), HSVCB(High Speed Vacuum Circuit Breaker), coordination with electric car. The results presented in the paper can be used as a reference for maintenance free in electric railway substation system.

• 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.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.119-127
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• 2015

PURPOSES : Before-and-after studies of red light cameras were conducted with the aim of reducing the number of side right-angle collisions. Three different methods were used for the before-and-after studies, and the analysis results were compared. METHODS : This research used the naive before-and-after method, the comparison-group method, and the empirical Bayes method to study the effects of red light cameras on side-angle collisions. The results of the three before-and-after methods were compared and interpreted in terms of safety indications at signalized intersections. RESULTS : The research results showed that side right-angle collisions can be reduced by installing red light cameras at signalized intersections. All three methods guarantee safety improvements of 25~30% on average. With regard to the results of each method, the naive before-and-after method, the comparison-group method, and the empirical Bayes method showed safety improvements of 25.6%, 27.8%, and 29.7%, respectively. CONCLUSIONS : It was concluded that red light cameras are an effective countermeasure to improve intersection safety. In particular, by installing red light cameras, side right-angle collisions can be reduced by up to approximately 25~30%.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.97-106
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• 1998

This study was carried out to investigate the problem of analysis method of circular sliding, which uses a high rate to work out a countermeasure for landslides. The results of this study were summarized as follows : 1. As a result of the analysis of sliding surface along the soil layers in forty model slopes, the boundary layer in weathered soil and weathered rock indicated a very high possibility of sliding than in other places. 2. Because most landslides in Korea occur along the discontinuity face at the boundary of soil layers, below 2m. from land surface, it is a good method for safe design to work the countermeasure for these kinds of landslides in cutting slopes. 3. When the inclination of slopes is fixed and the length of slopes is changed, the cercular sliding slopes were more safe as the soil layers are more shallow and the length of slopes are shorter, but the safety ratio of infinite sliding slopes was same as the other even though their length of slopes was different. 4. As a result of the analysis by cercular sliding analysis method and infinite sliding analysis method with some condition that the inclination of slopes was $30^{\circ}$ degree, because most landslides in Korea occur at this condition, these methods indicated different results to each other as well as cercular sliding analysis method showed too much safety ratio than infinite sliding analysis method.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.161-165
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• 1990

KEPCO has experienced eight oil leakage failures due to POF cable corrosion in the 154KV underground POF cable transmission line since the line was operated in 1976. Experimentally, We have verified that the cause of the failure is electrolytic corrosion of the cable owing to subway leakage current. For the countermeasure, We adopted the total Cathodic Protection System by the use of Victim Anode, Forced Drainage Method and Impressed Current Method with polarization cell.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.53-59
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• 2020

Malicious file upload attacks mean that the attacker to upload or transfer files of dangerous types that can be automatically processed within the web server's environment. Uploaded file content can include exploits, malware and malicious scripts. An attacker can user malicious content to manipulate the application behavior. As a method of detecting a malicious file upload attack, it is generally used to find a file type by detecting a file extension or a signature of the file. However, this type of file type detection has the disadvantage that it can not detect files that are not encoded with a specific program, such as PHP files. Therefore, in this paper, research was conducted on how to detect and block any program by using essential commands or variable names used in the corresponding program when writing a specific program. The performance evaluation results show that it detected specific files effectively using the suggested method.