• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.47-55
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• 2020

In this case study, the brake line failure of air over hydraulic(AOH) brake system is described. AOH brake system is applied to commercial vehicles between 5 to 8 tons. It consists of a hydraulic system using compressed air and operates the air master to form hydraulic pressure to transfer braking power to the wheels. When the brake lines of the system applied to vehicles with high load capacity are damaged, the braking force of one shaft is lost, and the braking distance increases rapidly, leading to a big accident. Failure of the brake line occurs due to various causes such as road surface fragmentation, corrosion of the line, and aged deterioration of air brake hose. The braking force could be decreased even when a very small break in the form of a pin-hole occurs. However, it is difficult to find a part where the thickness of the line is thin due to stone pecking or corrosion generated in the pin-hole formed on the brake line located under the lower part of the vehicle by the sensory evaluation or the conventional braking force test. Accordingly, it is necessary to analyze the condition and cause of the failure of the brake line more precisely when the accident investigation of the heavy vehicles, and also to examine the necessity of the advanced test for the aged brake line.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.1
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• pp.24-30
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• 2006

The Controller Area Network (CAN) is being widely used for real-time control application and small-scale distributed computer controller systems. When the stuff bits are generated by bit-stuffing mechanism in the CAN network, it causes jitter including variations in response time and delay In order to eliminate this jitter, stuff bits must be controlled to minimize the response time and to reduce the variation of data transmission time. This paper proposes the method to reduce the stuff bits by restriction of available identifier and bit mask using exclusive OR operation. This da manipulation method are pretty useful to the real-time control strategy with respect to performance. However, the CAN may exhibit unfair behavior under heavy traffic conditions. When there are both high and low priority messages ready for transmission, the proposed precedence priority filtering method allows one low priority message to be exchanged between any two adjacent higher priority messages. In this way, the length of each transmission delays is upper bounded. These procedures are implemented as local controllers for the ISHURO(Inha Semvung Humanoid Robot).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1436-1441
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• 2016

Currently, partial discharge diagnosis in the field of prevention applied technology and diagnostic equipment is a possible strong limit to remove the noise generated by external or internal I still have one unreliable diagnosis. This technology is the noise removal from signal the time lag analysis algorithms technique is applied by a fundamental. Increasing the reliability in terms of technology spectrum frequence of analysis method for by applying the acquisition through the position of the frequency content and sources of traffic lights partial discharge of the acquisition of signal analysis to judge whether a way diagnosis the environment of the scene, and conditions. Partial discharge signal and make the discharge while building blocks were found through the Analysis. Spectrum frequence of Analysis and wide discharge part, to be more precise, in line with the various functions, including the analysis technique band. Diagnosis and comes up with advanced technology that can detect the presence of a position. This method is portable single device developed for maintenance and mobility and ease and convenience of getting caught by discharge of the pattern analysis and position detection method suitable for a new diagnosis will suggest.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.165-174
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• 2019

They are frequently used today in public places such as street, subway, school or library. Since users can sometimes print documents that contain confidential data using Printer Kiosks, the devices should store and manage the documents securely. In this paper, we identify potential security threats in Printer Kiosks and suggest practical attack scenarios that can take place. To show the feasibility of suggested attack, we analyzed network traffic that were generated by the real Printer Kiosk device. As a result of our analysis, we have found that attackers can access other users' scanned files and access other users' documents from Printer Kiosk's home page. We confirmed that using our attack, we could retrieve other users' personal data.

• International Journal of Advanced Culture Technology
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• v.7 no.3
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• pp.143-148
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• 2019

In order to solve the urban problems caused by the increase of the urban population, the construction of smart city applying the latest technology is being carried out all over the world. In particular, we will create a smart city platform that utilizes data generated in the city to collect and store and analyze, thereby enhancing the city's continuous competitiveness and resilience and enhancing the quality of life of citizens. However, existing smart city platforms are not enough to construct a platform for smart city as a platform for solution elements such as IoT platform, big data platform, and AI platform. To complement this, we will reanalyze the existing overseas smart city platform and IoT platform in a comprehensive manner, combine the technical elements applied to it, and apply it to the future Korean smart city platform. This paper aims to investigate the trends of smart city platforms used in domestic and foreign countries and analyze the technology applied to smart city to study smart city platforms that solve various problems of the city such as environment, energy, safety, traffic, environment.

• Advances in aircraft and spacecraft science
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• v.6 no.5
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• pp.391-407
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• 2019

Flight trajectory optimization has become an important factor not only to reduce the operational costs (e.g.,, fuel and time related costs) of the airliners but also to reduce the environmental impact (e.g.,, emissions, contrails and noise etc.) caused by the airliners. So far, these factors have been dealt with in the context of 2D and 3D trajectory optimization, which are no longer efficient. Presently, the 4D trajectory optimization is required in order to cope with the current air traffic management (ATM). This study deals with a cubic spline approximation method for solving 4D trajectory optimization problem (TOP). The state vector, its time derivative and control vector are parameterized using cubic spline interpolation (CSI). Consequently, the objective function and constraints are expressed as functions of the value of state and control at the temporal nodes, this representation transforms the TOP into nonlinear programming problem (NLP). The proposed method is successfully applied to the generation of a minimum length optimal trajectories along 4D waypoints, where the method generated smooth 4D optimal trajectories with very accurate results.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.9-19
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• 2019

Service and users over the Internet are increasing rapidly. Cyber attacks are also increasing. As a result, information leakage and financial damage are occurring. Government, public agencies, and companies are using security systems that use signature-based detection rules to respond to known malicious codes. However, it takes a long time to generate and validate signature-based detection rules. In this paper, we propose and develop signature based detection rule generation and verification systems using the signature extraction scheme developed based on the LDA(latent Dirichlet allocation) algorithm and the traffic analysis technique. Experimental results show that detection rules are generated and verified much more quickly than before.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1689-1701
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• 2019

In recent years, personal videos have been shared online due to the popular uses of portable devices, such as smartphones and action cameras. A recent report predicted that 80% of the Internet traffic will be video content by the year 2021. Several studies have been conducted on the detection of main video events to manage a large scale of videos. These studies show fairly good performance in certain genres. However, the methods used in previous studies have difficulty in detecting events of personal video. This is because the characteristics and genres of personal videos vary widely. In a research, we found that adding a dataset with the right perspective in the study improved performance. It has also been shown that performance improves depending on how you extract keyframes from the video. we selected frame segments that can represent video considering the characteristics of this personal video. In each frame segment, object, location, food and audio features were extracted, and representative vectors were generated through a CNN-based recurrent model and a fusion module. The proposed method showed mAP 78.4% performance through experiments using LSVC data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3138-3150
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• 2021

Multimedia services on the Internet are continuously increasing. Accordingly, the demand for a technology for efficiently delivering multimedia traffic is also constantly increasing. The multicast technique, that delivers the same content to several destinations, is constantly being developed. This technique delivers a content from a source to all destinations through the multicast tree. The multicast tree with low cost increases the utilization of network resources. However, the finding of the optimal multicast tree that has the minimum link costs is very difficult and its calculation complexity is the same as the complexity of the Steiner tree calculation which is NP-complete. Therefore, we need an effective way to obtain a multicast tree with low cost and less calculation time on SDN-based smart network platforms. In this paper, we propose a new multicast tree generation algorithm which produces a multicast tree using an agent trained by model-based meta reinforcement learning. Experiments verified that the proposed algorithm generated multicast trees in less time compared with existing approximation algorithms. It produced multicast trees with low cost in a dynamic network environment compared with the previous DQN-based algorithm.

• Journal of Wellbeing Management and Applied Psychology
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• v.4 no.2
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• pp.35-41
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• 2021

Purpose: In this study, volatile organic compounds(VOCs) and aldehydes generated from roadside vehicles and other pollutants were measured and analyzed. Research design, data and methodology: As a result of measuring and analyzing three areas near the roadside, Vinyl chloride 0.00 ~ 0.02 ppb, Benzene 2.87 ~ 5.01 ppb. Toluene 4.51 ~ 8.62 ppb, Styrene 0.00 ~ 0.34 ppb, Formaldehyde 8.45 ~ 17.12 ug/m³, Acetaldehyde 7.01 ~ 17.64 ug/m³ were detected. When comparing the analysis results and the 6-month average concentration of the hazardous air monitoring network, the analysis results were about 26 times higher for Benzene, about 5 times for Toluene, and about 3.75 times for Styrene. In the case of vinyl chloride, it was confirmed that it was about 20 times lower than that of the hazardous atmosphere monitoring network. Results: Therefore, it is necessary to reexamine the installation location of the measurement network because people are exposed to pollutants on the actual roadside. It is judged that it is right to build a measurement network that is practically helpful to people by increasing the measurement items in the measurement network.