• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.68-76
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• 2011

Acoustic emission(AE) has emerged as a powerful nondestructive tool to detect any further growth or expansion of preexisting defects or to characterize failure mechanisms. Recently, this kind of technique, that is an in-situ monitoring of inside damages of materials or structures, becomes increasingly popular for monitoring the integrity of large structures like a huge wind turbine blade. Therefore, it is required to find a symptom of damage propagation before catastrophic failure through a continuous monitoring. In this study, a new damage location method has been proposed by using signal mapping algorithm, and an experimental verification is conducted by using small wind turbine blade specimen; a part of 750 kW real blade. The results show that this new signal mapping method has high advantages such as a flexibility for sensor location, improved accuracy, high detectability. The newly proposed method was compared with traditional AE source location method based on arrival time difference.

• Smart Structures and Systems
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• v.18 no.4
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• pp.643-662
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• 2016

The monitoring of structural integrity of pipeline tapered thread connections is of great significance in terms of safe operation in the industry. In order to detect effectively the loosening degree of tapered thread connection, an active sensing method using piezoceramic transducers was developed based on time reversal technique in this paper. As the piezoeramic transducers can be either as actuators or sensors to generate or detect stress waves, the energy transmission for tapered thread connection was analyzed. Subsequently, the detection principle for tapered thread connection based on time reversal was introduced. Finally, the inherent relationship between the contact area and tightness degree of tapered thread connection for the pipe structural model was investigated. Seven different contact area scenarios were tested. Each scenario was created by loosening connectors ranging from 3 turns to 4.5 turns in the right tapered threads when the contact area in the left tapered threads were 4.5 turns. The experiments were separately conducted with a highly noisy environment and various excitation signal amplitudes. The results show the focused peaks based on time reversal have the monotonously rising trend with the increase of the contact areas of tapered threads within an acceptable monitoring resolution for metal pipes. Compared with the energy method, the proposed time reversal based method to monitor tapered threads loosening demonstrates to be more robust in rejecting noise in Structural Health Monitoring (SHM) applications.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7409-7414
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• 2015

Loop-mediated isothermal amplification (LAMP) developed by Notomi et al. (2000) has made it possible to amplify DNA with high specificity, efficiency and rapidity under isothermal conditions. The ultimate products of LAMP are stem-loop structures with several inverted repeats of the target sequence and cauliflower-like patterns with multiple loops shaped by annealing between every other inverted repeats of the amplified target in the similar strand. Because the amplification process in LAMP is achieved by using four to six distinct primers, it is expected to amplify the target region with high selectivity. However, evaluation of reaction accuracy or quantitative inspection make it necessary to append other procedures to scrutinize the amplified products. Hitherto, various techniques such as turbidity assessment in the reaction vessel, post-reaction agarose gel electrophoresis, use of intercalating fluorescent dyes, real-time turbidimetry, addition of cationic polymers to the reaction mixture, polyacrylamide gel-based microchambers, lateral flow dipsticks, fluorescence resonance energy transfer (FRET), enzyme-linked immunosorbent assays and nanoparticle-based colorimetric tests have been utilized for this purpose. In this paper, we reviewed the best-known techniques for evaluation of LAMP amplicons and their applications in molecular biology beside their advantages and deficiencies. Regarding the properties of each technique, the development of innovative prompt, cost-effective and precise molecular detection methods for application in the broad field of cancer research may be feasible.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3829-3833
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• 2012

Objective: The objective of this study was to examine the practice and associated factors of breast self-examination (BSE) among Malaysian women. Methods: For this cross-sectional study 250 women were selected by a simple random sampling technique. The questionnaire was consisted of three parts: socio-demographic characteristics, knowledge about BSE, and practice of BSE. Obtained data was analyzed using SPSS version 13. T-test and ANOVA test were used to explore the relation between socio-demographic characteristics and the practice of BSE. Results: About 32% of the participants reported that they have had family history of cancer and about 20% of the participants reported that they have had family history of breast cancer. The majority of the participants (88.8%) have heard about breast cancer and 78.4% of the participants have heard about BSE. Race, marital status, residency, regular exercise, awareness about breast cancer, belief that breast cancer can be detected early, belief that early detection improves the chance of survival, family history of cancer, family history of breast cancer, awareness about BSE, and belief that BSE is necessary, significantly influenced the practice of BSE among women. Practice of BSE on monthly basis was found to be 47.2% among the study participants. Conclusions: The socio-demographic characteristics significantly influence the practice of BSA among women in Malaysia. The findings of this study might not only influence the planning of specific screening interventions and strategies in Malaysia but might also be important for the relevant international communities, interested in the peculiarities of BSE incidence in different countries.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.221-227
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• 2013

This paper proposes an improved steganalysis method based on image categorization. In general, most steganalysis methods extract the statistical moments based features which contain the global natures of images regardless of their inherent characteristics. However, the steganalysis method based on the statistical moments leads to degraded performance by applying to images with different complexity. In this paper, we decompose an 8-bit image into an upper 4-bit plane and a lower 4-bit plane, and categorize the image with two classes according to the correlation coefficient between decomposed sub-images. Two independent steganalyses can be performed for the categorized images. Since our method uses independent steganalysis technique according to the image category, it can reduce the drawback of the steganalysis methods utilizing the statistical moments. The performance of the proposed scheme is compared with well-known four steganalysis methods. Experiment results show that the proposed scheme has higher detection rate than previous methods.

• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.40-48
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• 2006

This paper presents a new rooftop surface estimation method from 3D line segments. 3D rooftop surface estimation is based on the hierarchical grouping and initiated by 3D line merging for the disconnected 3D line segments. Merged 3D lines are applied to the detection of rooftop by surface estimating technique. To estimate surfaces we detect L-corner and T-corner points, and find fixed reliable junction points. The hypothesis of the possible rooftop surfaces are estimated as polygonal surfaces by these fixed junction points and building's rooftop models are generated by testing the possible surfaces in terms of assumptions of building surface properties. We carried out experiments by synthetic images on Avenches data set and the experimental results showed that we could reliably build 3D model with 3D surfaces, errors of which came up with 0.4 - 1.3 meter, 2.5 times more accurate than the elevation date from the conventional area-based stereo.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.199-207
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• 2013

Recently, hacking is seen as a criminal activity beyond an activity associated with curiosity in the beginning. The malignant bot which is used as an attack technique is one of the examples. Malignant Bot is one of IRC Bots and it leaks user's information with attacker's command by attacking specified IP range. This paper will discuss an access method and a movement process by analyzing shadowbot which is a kind of a malignant Bot and will suggest possible countermeasure. This study has two distinct features. First, we analyze malignant Bot by analyzing tools such as VM ware. Second, we formulate a hypothesis and will suggest possible countermeasure through analyzing malignant Bot's access method and movement. Performance evaluation will be conducted by applying possible countermeasure to see if it can prevent attacks from malignant bot.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.163-168
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• 2018

In this paper, we propose and develop a test automation program tool that automates GUI based testing using black box testing technique in Windows environment. The main features of the proposed test automation program tool are as follows. First, an error condition is designated as an image, a screen is captured for each test step, and an error message is detected through comparison of image similarity. Second, the proposed system supports various setting options such as event waiting time during execution and coordinate increment value between each test step. Such black box test automation research was common in environments such as Android and Web, but not in Windows environment. The results of performance evaluation show that the proposed system performs GUI test automation as an image comparison module and confirms that the test is performed normally by confirming process status and error image detection.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.98-105
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• 2003

We propose a new technique of deinterleaving multiple radar pulse sequences by means of genetic algorithm for threat identification in electronic warfare(EW) system. The conventional approaches based on histogram or continuous wavelet transform are so deterministic that they are subject to failing in detection of individual signal characteristics under real EW signal environment that suffers frequent signal missing, noise, and counter-EW signal. The proposed algorithm utilizes the probabilistic optimization procedure of genetic algorithm. This method, a time-of-arrival(TOA) only strategy, constructs an initial chromosome set using the difference of TOA. To evaluate the fitness of each gene, the defined pulse phase is considered. Since it is rare to meet with a single radar at a moment in EW field of combat, multiple solutions are to be derived in the final stage. Therefore it is designed to terminate genetic process at the prematured generation followed by a chromosome grouping. Experimental results for simulated and real radar signals show the improved performance in estimating both the number of radar and the pulse repetition interval.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.160-170
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• 2010

This paper proposes a Haar Wavelet Feature Detector (HWFD) based on the Haar wavelet transform and average box filter. By decomposing the original image using the Haar wavelet transform, the proposed detector obtains the variance information of the image, making it possible to extract more distinctive features from the original image. For detection of interest points that represent the regions whose variance is the highest among their neighbor regions, we apply the average box filter to evaluate the local variance information and use the integral image technique for fast computation. Due to utilization of the Haar wavelet transform and the average box filter, the proposed detector is robust to illumination change, scale change, and rotation of the image. Experimental results show that even though the proposed method detects fewer interest points, it achieves higher repeatability, higher efficiency and higher matching accuracy compared with the DoG detector and Harris corner detector.