• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.115-125
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• 2011

The smartphones which have been recently are embedded with high resolution quality camera, assisted GPS, accelerometer, gyroscope and various sensors including magnetometer sensor that could be directly used for measurement. This study aims to suggest the possible application of smartphone camera providing high resolution images in terms of photogrammetry by calibrating it and assessing its accuracy. First of all, prior to the accuracy assessment of smartphone camera, camera calibration was conducted to correct lens distortion of each camera and the accuracy of image coordinates and object coordinates calculated by bundle adjustment during this procedure was analyzed. Also regarding three-dimensional positioning, result analysis depending on considering lens distortion coefficients was conducted, and finally relative accuracy of smartphone camera on metric camera was assessed. The result showed that in terms of distortion correction of smartphone camera, also higher order symmetric radial lens distortion coefficients should be considered, and three dimensional position determined by smartphone images was a little difference from that by metric camera. Therefore it is expected that smartphone images have huge possibility to be used for photogrammetry.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.313-318
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• 2006

This paper introduces a partial discharge (PD) severity metric, S, based on the evaluation of time-sequence PD data capture and resulting Time-Sequence-Analysis Discharge (TSAD) level distributions. Basically based on an IEC60270 measurement technique, each PD event is time stamped and the discharge level noted. By evaluating the time differences between a previous and subsequent discharge, a 3D plot of time-sequence activity and discharge levels can be produced. From these parameters a measurement of severity, which takes into account dynamic or instantaneous variations in both the time of occurrence and the level of discharge, rather than using standard repetition rate techniques, can be formulated. The idea is to provide a measure of the severity of PD activity for potentially measuring the state of insulation within an item of plant. This severity measure is evaluated for a simple point-plane geometry in $SF_{6}$ as a function of gap distance and applied high voltage. The results show that as the partial discharge activity increases, the severity measure also increases. The importance of future investigations, quantifications and evaluations of the robustness, sensitivity and importance of such a severity measurement, as well as comparing it with typical repetition rate assessment techniques, and other monitoring techniques, are also very briefly discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.120-128
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• 2017

The refraction phenomenon of radio waves should be considered to improve the detection accuracy of target altitudes for long-range surveillance radars, however, it is difficult to estimate accurate refractivity of atmosphere for every location. In this paper, we propose the atmosphere evaluation metric(AEM) to estimate atmospheric conditions at target locations using target altitudes obtained from primary surveillance radar(PSR) and secondary surveillance radar(SSR). To verify the suitability of the proposed metric, we observed atmospheric conditions and calculated estimation errors of target altitudes using measured data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.768-777
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• 2020

In this paper, we describe recent research results on AODV routing protocol, which is widely deployed at mobile ad hoc networks, and AODV related routing protocols with multi-path routing schemes. We suggest the critical problems which minimum hop routing schemes have, such as AODV routing protocol, and then, propose a new C-AODV routing protocol with two routing metrics: the primary metric is the hop count, the secondary metric is the sum of link delay times. We implemented C-AODV protocol by modifying AODV at the NS-3, and thus, elaborate on how we change the original AODV source code of NS-3 in order to implement the C-AODV scheme. We show numerical comparison of C-AODV scheme with the original AODV scheme and then, discuss how much the C-AODV enhances routing performance over AODV protocol. In conclusion, we present future research items.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.53-60
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• 2024

Security assessment is an indispensable process for a secure network, and appropriate performance indicators must be present to manage risks. The most widely used quantitative indicator is CVSS. CVSS has a problem that it cannot consider context in terms of subjectivity, complexity of interpretation, and security risks. To compensate for these problems, we propose indicators that itemize and quantify four things: attackers, threats, responses, and assets, taking into account the security context of ISO/IEC 15408 documents. Vulnerabilities discovered through network scanning can be mapped to MITREATT&CK's technology by the connection between weaknesses and attack patterns (CAPEC). We use MITREATT&CK's Groups, Tactic, and Mitigations to produce consistent and intuitive scores. Accordingly, it is expected that security evaluation managers will have a positive impact on strengthening security such as corporate networks by expanding the range of choices among security indicators from various perspectives.

• Investigative and Clinical Urology
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• v.63 no.3
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• pp.301-308
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• 2022

Purpose To diagnose lower urinary tract symptoms (LUTS) in a noninvasive manner, we created a prediction model for bladder outlet obstruction (BOO) and detrusor underactivity (DUA) using simple uroflowmetry. In this study, we used deep learning to analyze simple uroflowmetry. Materials and Methods We performed a retrospective review of 4,835 male patients aged ≥40 years who underwent a urodynamic study at a single center. We excluded patients with a disease or a history of surgery that could affect LUTS. A total of 1,792 patients were included in the study. We extracted a simple uroflowmetry graph automatically using the ABBYY Flexicapture^® image capture program (ABBYY, Moscow, Russia). We applied a convolutional neural network (CNN), a deep learning method to predict DUA and BOO. A 5-fold cross-validation average value of the area under the receiver operating characteristic (AUROC) curve was chosen as an evaluation metric. When it comes to binary classification, this metric provides a richer measure of classification performance. Additionally, we provided the corresponding average precision-recall (PR) curves. Results Among the 1,792 patients, 482 (26.90%) had BOO, and 893 (49.83%) had DUA. The average AUROC scores of DUA and BOO, which were measured using 5-fold cross-validation, were 73.30% (mean average precision [mAP]=0.70) and 72.23% (mAP=0.45), respectively. Conclusions Our study suggests that it is possible to differentiate DUA from non-DUA and BOO from non-BOO using a simple uroflowmetry graph with a fine-tuned VGG16, which is a well-known CNN model.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.3
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• pp.235-245
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• 2019

This research focuses on the relationships among customer satisfaction, delight, and loyalty. Although customer delight is one facet of an affective evaluation that can be predicted from customer satisfaction as cognitive component of the evaluation, there is no empirical examination on the casual relationship among customer satisfaction, delight, and loyalty. This study aims at addressing this gap in the service literature. The research questions are (1) How is customer satisfaction related to customer delight? and (2) Does customer delight matter in the relationship between customer satisfaction and loyalty? Data from a survey of consumers across upscale restaurant and retail bank in Korea were obtained. Our results show that customer satisfaction contributes positively to customer delight, and that customer delight plays a significant role in the relationship between customer satisfaction and loyalty. This chained relationship from customer satisfaction to customer delight to customer loyalty suggests that achieving customer delight represents one of the underlying pathways through which basic or core requirements expected by customers are satisfied. Our finding suggests that service firms need to monitor and manage their levels of customer delight as a performance metric, and delighting customers may be an important strategy to build competitive advantage through customer loyalty.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.112-120
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• 2008

Today, the use of a vacuum cleaner gave us the higher quality of life than past time, but sometimes made us w1comfortable in the house because of the specific noise that is annoying. So we need to study how sound absorbtion materials affect sound power level and sound quality with sound metrics. In this paper, we will measure and calculate sound power level for vacuum cleaner and analyze characteristics of the noise for 10 Signals according to materials positioned in vacuum cleaner. The multiple regression analysis can estimate the nonlinear characteristics of relation between subjective evaluation and sound metrics. So we will develop sound quality index for vacuum sound.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.156-163
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• 2008

This study was to introduce a methodology of ecological health assessment for efficient management and to provide some diagnostic results of the survey. We evaluated ecological health assessment at five sampling locations of Sikjang Mountainous Stream using the index of biological integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) during May - October 2006. The health condition, based on the IBI model, averaged 32 and varied from 27 to 37 depending on the sampling sites. Thus, the stream health was judged as "good" to "fair" conditions. IBI values showed slight differences between upstream and downstream sites. Whereas, QHEI values varied from 75 (fair condition) to 196 (excellent condition) and QHEI at St. 4~5, indicating the downstream reach had significantly lower than the headwater site (St.1). Regression analyses also showed that QHEI values had a linear decrease from the headwater to downstream. This result indicated that habitat quality was rapidly degradated by human influence. Overall, data of IBI and QHEI suggested that the stream health was maintained well in the present but the habitat and biological quality were partially degradated in the downstream. So, the human interference should be minimized to protect the downstream environment.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.226-235
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• 1998

This study proposes the analysis and evaluation of method of time series of ultrasonic signal using the chaotic feature extraction for ultrasonic pattern recognition. The features are extracted from time series data for analysis of weld defects quantitatively. For this purpose, analysis objectives in this study are fractal dimension, Lyapunov exponent, and strange attractor on hyperspace. The Lyapunov exponent is a measure of rate in which phase space diverges nearby trajectories. Chaotic trajectories have at least one positive Lyapunov exponent, and the fractal dimension appears as a metric space such as the phase space trajectory of a dynamical system. In experiment, fractal(correlation) dimensions and Lyapunov exponents show the mean value of 4.663, and 0.093 relatively in case of learning, while the mean value of 4.926, and 0.090 in case of testing in slag inclusion(weld defects) are shown. Therefore, the proposed chaotic feature extraction can be enhancement of precision rate for ultrasonic pattern recognition in defecting signals of weld zone, such as slag inclusion.