• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1511-1519
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• 2012

Pipe structures contain many welded zones, and ultrasonic tests are increasingly being performed by using automated testing devices in order to evaluate the weld integrity. An electromagnetic acoustic transducer (EMAT) is a noncontact transducer that can transmit or receive ultrasonic waves without a couplant. Furthermore, it can easily generate specific guided waves such as SH (shear horizontal) or Lamb waves by altering the design of the coil and magnet. Therefore, an EMAT should be useful for application to an automated ultrasonic inspection system. In this study, SH waves generated using an EMAT were applied to inspect the pipe-weld zone. To analyze the specific SH mode (SH0) from the SH wave signals, wavelet transform was applied. It was found that flaws could be detected precisely because the intensity of the $SH_0$ mode-frequency, which is analyzed by using wavelet transform, is proportional to the length of the flaw.

• Journal of KIISE:Software and Applications
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• v.32 no.8
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• pp.704-716
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• 2005

Assembling new software systems from Prepared components is an attractive alternative to traditional software development method to reduce development cost and schedule dramatically. However, if separately developed components are tested, integrated and verified with unreasonable effort and high cost, it would not be an effective way to software development. Components are not distributed in the shape of white-box source code so that should be hard to validate and test in new application environment. For solving this problem, built-in tester components are suggested to check the contract-compliance of their server components. If components have various and complex function, built-in tester should be heavy and unflexible to test in composition of components. This paper suggests enhancing automated wrapper technique which substitutes with built-in tester components and shows the usability of the wrapper by design and implementation. Component testing in this way reduces the cost and effort associated with preparation of component testing and makes the various test experiments in components assembly.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.1
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• pp.91-102
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• 2019

Autonomous vehicles can be exposed to severe danger when failure occurs in any of its components. For this reason many countries are making efforts on the legislative issue how to objectively evaluate failure safety of an autonomous vehicle when such a vehicle is commercially available to a customer in the near future. In level-3 automation, a driver must take over the control of his vehicle when failure occurs, and the driver's controllability must be secured for escape from the imminent danger. In this paper, quantitative methods have been developed for evaluating failure safety of the level-3 autonomous vehicle, and they were validated by simulation. And also, we confirmed that the proposed evaluation method can quantitatively evaluate the failure safety.

• Journal of Apiculture
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• v.32 no.3
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• pp.191-198
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• 2017

Vespa hornets are notorious predators of honeybees in Korean beekeeping. Detection of vespa hornet attacking on honeybee colony was tried through analysis of wing beat frequency profiling from Vespa mandarinia. Wing beat profiles of V. mandarinia during active flight and resting were distinctively different. From the wing beat profiling, algorithm of automated detection of vespa attack was encoded, and alert system was developed using Teensy 3.2 and Raspberry pi 3. From the laboratory testing, the prototype system successfully detected vespa wing beats and delivered the vespa attack information to the user wirelessly. Further development of the system could help precision alert system of the vespa attack to apiary.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.250-256
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• 2009

This paper presents a robotic tower-crane system using encoder and gyroscope sensors as path tracking devices. Tower crane work is often associated with falling accidents and industrial disasters. Such problems often incur a loss of time and money for the contractor. For this reason, many studies have been done on an automatic tower crane. As a part of 5-year 23-million-dollar research project in Korea, we are developing a robotic tower crane which aims to improve the safety level and productivity. We selected a luffing tower crane, which is commonly used in urban construction projects today, as a platform for the robotic tower crane system. This system comprises two modules: the automated path planning module and the path tracking module. The automated path planning system uses the 3D Cartesian coordinates. When the robotic tower crane lifts construction material, the algorithm creates a line, which represents a lifting path, in virtual space. This algorithm seeks and generates the best route to lift construction material while avoiding known obstacles from real construction site. The path tracking system detects the location of a lifted material in terms of the 3D coordinate values using various types of sensors including adopts encoder and gyroscope sensors. We are testing various sensors as a candidate for the path tracking device. This specific study focuses on how to employ encoder and gyroscope sensors in the robotic crane These sensors measure a movement and rotary motion of the robotic tower crane. Finally, the movement of the robotic tower crane is displayed in a virtual space that synthesizes the data from two modules: the automatically planned path and the tracked paths. We are currently field-testing the feasibility of the proposed system using an actual tower crane. In the next step, the robotic tower crane will be applied to actual construction sites with a following analysis of the crane's productivity in order to ascertain its economic efficiency.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.6
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• pp.547-558
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• 2008

Embedded system is tightly coupled with heterogeneous layers such as application, as kernel, device driver, HAL and hardware. Embedded system is customized for the specific purpose and hardware. In addition, the product cycle is so fast that software and hardware, which are developed by several vendors, are integrated together under unstable status. Therefore, there are lots of possibilities of faults in all layers. Because embedded software developers test their codes integrated with faulty layers, they cannot confirm 'whether testing of every aspects was completed, their code was failed, or integrated software/hardware has some problems'. In this paper, we propose an embedded software interface test method and a test tool called Justitia for detecting faults and tracing causes in the interface among heterogeneous layers. The proposed technique is an automated method which improves debugging upto professional testing using an emulator for helping developer.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.10
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• pp.679-690
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• 2013

Smartphones have features that users feel free to install/delete the program they want. Their emergence makes many developers rush into the Smartphone application development market. Thus, developing good applications quickly is becoming even more intense competition in the market. Because, however, the application development and deployment procedures are simple in the Android environments and anyone can participate in the development easily, applications not validated thoroughly are likely to be deployed. Therefore, a systematic approach that can verify Android-based applications with fewer burdens is required. In this paper, we propose a method that generates automatically GUI-based testing scenarios for the Android applications. The automated test scenario generation can reduce the time which the developer spends on testing, thus it can improve the productivity of the development in the testing phase.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.331-345
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• 2021

Virtual testing is considered a major requirement for the safety verification of autonomous driving functions. For virtual testing, both the autonomous vehicle and the driving environment should be modeled appropriately. In particular, a realistic modeling of the perception sensor system such as the one having a camera and radar is important. However, research on modeling to consistently generate realistic perception results is lacking. Therefore, this paper presents a sensor modeling method to provide realistic object detection results in a MILS (Model in the Loop Simulation) environment. First, the key parameters for modeling are defined, and the object detection characteristics of actual cameras and radar sensors are analyzed. Then, the detection characteristics of a sensor modeled in a simulation environment, based on the analysis results, are validated through a correlation coefficient analysis that considers an actual sensor.

• Smart Structures and Systems
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• v.13 no.6
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• pp.901-925
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• 2014

The reliability of a Bridge management System depends on the quality of visual inspection and the reliable estimation of bridge condition rating. However, the current practices of visual inspection have been identified with several limitations, such as: they are time-consuming, provide incomplete information, and their reliance on inspectors' experience. To overcome such limitations, this paper presents an approach of automating the prediction of condition rating for bridges based on digital image analysis. The proposed methodology encompasses image acquisition, development of 3D visualization model, image processing, and condition rating model. Under this method, scaling defect in concrete bridge components is considered as a candidate defect and the guidelines in the Ontario Structure Inspection Manual (OSIM) have been adopted for developing and testing the proposed method. The automated algorithms for scaling depth prediction and mapping of condition ratings are based on training of back propagation neural networks. The result of developed models showed better prediction capability of condition rating over the existing methods such as, Naïve Bayes Classifiers and Bagged Decision Tree.

• Journal of KIISE:Software and Applications
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• v.34 no.8
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• pp.708-720
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• 2007

Memory access errors are frequently occurred in computer programs written in C programming language [1,2]. Accordingly, a number of research works have suggested a wide variety of methods to detect such errors automatically. However, they have one or more of the following problems: inability to detect all memory errors, changing the memory allocation mechanism, and excessive performance overhead. To cope with these problems, in this paper we suggest a new and automated tool to detect dynamic memory access errors in C programs.