• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.165-170
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• 2014

Shear horizontal (SH) waves propagate as a type of plate wave in a thin sheet. The dispersion characteristics of SH waves can be used for signal analysis. Therefore, SH-waves are useful for monitoring the structural health of a thin-sheet-structure. An electromagnetic acoustic transducer (EMAT), which is a non-contact ultrasonic transducer, can generate SH-waves easily by varying the shape and array of magnets and coils. Therefore, an EMAT can be applied to an automated ultrasonic testing system for structural health monitoring. When used as a sensor, however, the EMAT has a weakness in that electromagnetic interference (EMI) noise can occur easily in the automated system because of motors and electric devices. Alternatively, a fiber optic sensor works well in the same environment with EMI noise because it uses a light signal instead of an electric signal. In this paper, a fiber Fabry-P$\acute{e}$rot interferometer (FFPI) was proposed as a sensor to receive the SH-waves generated by an EMAT. A simple test was performed to verify the performance of the FFPI sensor. It is thus shown that the FFPI can receive SH-wave signals clearly.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.806-818
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• 2009

Since the invention of the integrated circuit (IC) in 1950s, semiconductor technology has undergone dramatic development up to these days. A complete semiconductor is manufactured through a diversity of processes. For better semiconductor productivity, fault detection and classification (FDC) has been rigorously studied for finding faults even before the processes are completed. For FDC, various kinds of sensors are attached in many semiconductor manufacturing devices, and sensor values are collected in a periodic manner. The collection of sensor values consists of sequences of real numbers, and hence is regarded as a kind of time-series data. In this paper, we propose an algorithm for detecting and clustering faults in semiconductor processes. The proposed algorithm is a modification of the existing anomaly detection algorithm dealing with symbolically-represented time-series. The contributions of this paper are: (1) showing that a modification of the existing anomaly detection algorithm dealing with general time-series could be used for semiconductor process data and (2) presenting experimental results for improving correctness of fault detection and clustering. As a result of our experiment, the proposed algorithm caused neither false positive nor false negative.

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.381-388
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• 2008

In the common practice of air-photographing measurement aerial-photogrammetric, the location of camera at the time of photographing is identified by performing aerotriangulation. However, installing ground-base station to enable aerotriangulation takes majority portion of a map making cost. Aerial-photogrammetric has shown a great improvement helped by steady upgrading in equipment and development in quantitative study. Aerotriangulation can be replaced by Direct Georeferencing, which uses GPS/INS to identify a camera location and to produce detailed information. An innovative technique replacing aerotriangulation, it has a disadvantage that base station has to be available in the area of photographing. The study intends to suggest a method applying VRS in GPS/INS aerotriangulation. Despite the fact that Direct Georeferencing is the innovated technique which substitutes existing aerotriangulation, it still need to install the ground-base station in GPS/INS aerotriangulation. GPS/INS data was analyzed with 4 different cases in order to accomplish the purpose of this study. In addition, in the thesis, it was approved that VRS can be utilized to make small-scale map as accurate as base station. This study is expected to improve the efficiency of work by showing that VRS can be used not only in base station but also enabling base station in the ground-access challenging area.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.658-665
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• 2019

In the era of the rapid development of a tremendous number of new technologies and products, the emotional communication between products and users has become an important research topic. However, the user's emotional measurement methods have not been widely used in the field of product design. Besides, as an important space that can improve people's life quality and urban entertainment at the emotional level, seaside space also creates an atmosphere of frequent emotional communication among tourists, landscape and environmental facilities. To deduce the applicability and advantages and disadvantages of the experiential emotional measurement method in product design, this paper took the seaside seat users of Haeundae as the object and carried out the Self-report of the experiential emotional measurement method. Specifically, the experiment of Self-report was divided into two stages: prior survey and subsequent main investigation. Then the hypothesis was verified by using Bivariate Regression and Multiple Regression through SPSS. Furthermore, through the experiment of the Self-report, the applicability and advantages and disadvantages of experiential emotional measurement method in product design were derived. In the future, based on the applicability, advantages and disadvantages of the experiential emotional measurement method derived in this study, it is expected to become the fundamental and reliable data for the development of emotional measurement methods that can be suitable for product design.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.301-310
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• 2019

This study aims to examine eligibilities, services and delivery of services for the current end-of-life care and analyze the quality control of services for end-of-life care. We analyzed the literature and laws on end-of-life systems in Korean and the United States. Current end-of-life care, hospice and palliative care in Korea is being provided mainly in hospital setting. Quality control for the services focuses on setting the criteria for structures in hospitals (i.e. staffing, facilities and equipment). Whereas American end-of-life care system has much broader eligibility for service beneficiaries and provides care mostly at home. Also quality control for services includes process (delivering service) and outcomes, such as monitoring performance indicators and consumer's satisfaction. This is linked to annual payment. The comparative analysis findings contributed to give the next direction of current Korean end-of-life care system. It is nessary to establish the better and extensive end-of-life care system in Korea in considering other countries' end-of-life care systems based on more future research.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.504-509
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• 2019

Recently, both wireless communications technology and the performance of small devices have developed exponentially, while the number of services using various types of Internet of Things (IoT) devices has also massively increased in line with the ongoing technological and environmental changes. Furthermore, ever more devices that were previously used in the offline environment-including small-size sensors and CCTV-are being connected to the Internet due to the huge increase in IoT services. However, many IoT devices are not equipped with security functions, and use vulnerable open source software as it is. In addition, conventional network equipment, such as switches and gateways, operates with vulnerabilities, because users tend not to update the equipment on a regular basis. Recently, the simple vulnerability of IoT devices has been exploited through the distributed denial of service (DDoS) from attackers creating a large number of botnets. This paper proposes a system that is capable of identifying Internet-connected devices quickly, analyzing and managing the vulnerability of such devices using Internet-wide scan technology. In addition, the vulnerability analysis rate of the proposed technology was verified through collected banner information. In the future, the company plans to automate and upgrade the proposed system so that it can be used as a technology to prevent cyber attacks.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.2
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• pp.105-118
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• 2019

New manufactural innovation was generated with combination with Do It Yourself(DIY) culture and Information and Communication Technology(ICT). It led people to make their creative idea in real things and share them. This social movement has been called as 'Maker' culture. As maker culture was developed, the places named 'Makerspace' with high-tech equipment and sharing environment have been widely spread and gotten spotlight. Futhermore, makerspaces have been diffused rapidly in Korea; because of its importance for the fourth industrial revolution. However, the operation of makerspaces is not matured as much as its popularity, so problems occurred in operating aspects. The number of related studies is not enough to foster domestic maker culture in Korea. Of that, studies on operation of makerspaces were limited and the quantity of survey sample was insufficient. Therefore, firstly, in this study, operation elements of makerspaces were extracted by literature review. And, survey for examining the extracted elements was conducted to four policy makers and researchers, four makerspace operators and four makers. Final survey was carried out by Importance-Performance Analysis(IPA) method to fifty recipients composed of policy makers and researchers, operators, and makers. In result, importance located above performance in every elements and in-depth interview was followed to understand domestic surroundings and suggest way to invigorate makerspaces in Korea. The suggestion shows as follows. First, online and offline platform for makers should be expanded; second, makerspace should connect private sponsorship with makers or their projects; third, policy direction has to be improved from venturing business to diffusion of maker culture; fourth, basic maker education should be enlarged.

• The Journal of Bigdata
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• v.6 no.1
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• pp.23-35
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• 2021

In the era of the 4th industrial revolution, smart factories have received great attention, where production and manufacturing technology and ICT converge. With the development of IoT technology and big data, automation of production systems has become possible. In the advanced manufacturing industry, production systems are subject to unscheduled performance degradation and downtime, and there is a demand to reduce safety risks by detecting and reparing potential errors as soon as possible. This study designs a model based on supervised and unsupervised learning for detecting anomalies. The accuracy of XGBoost, LightGBM, and CNN models was compared as a supervised learning analysis method. Through the evaluation index based on the confusion matrix, it was confirmed that LightGBM is most predictive (97%). In addition, as an unsupervised learning analysis method, MD, AE, and LSTM-AE models were constructed. Comparing three unsupervised learning analysis methods, the LSTM-AE model detected 75% of anomalies and showed the best performance. This study aims to contribute to the advancement of the smart factory by combining supervised and unsupervised learning techniques to accurately diagnose equipment failures and predict when abnormal situations occur, thereby laying the foundation for preemptive responses to abnormal situations. do.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.135-143
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• 2021

Aerospace and geospatial technologies have become more accessible by researchers and agricultural practitioners, and these technologies can play a pivotal role in transforming current pest management practices in agriculture and forestry. During the past 20 years, technologies including satellites, manned and unmanned aircraft, spectral sensors, information systems, and autonomous field equipment, have been used to detect pests and apply control measures site-specifically. Despite the availability of aerospace and geospatial technologies, along with big-data-driven artificial intelligence, applications of such technologies to apple IPM have not been realized yet. Using a case study conducted at the Korea Apple Research Institute, this article discusses the advances and limitations of current aerospace and geospatial technologies that can be used for improving apple IPM.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.321-327
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• 2021

Wrist PA-grip view is used to diagnose triangular fibrocartilage complex (TFCC) tear because it can easily diagnose damage to the surrounding wrist ligaments. However, despite advances in radiology equipment, distortion of images due to geometric elements still has many limitations. In this paper, we propose a method that can minimize the distortions of images by analyzing the distortions occurring in the wrist PA-grip view. A source of image distance (SID) were set at 130 cm and 150 cm for comparison with 110 cm. Depending on the SID, the phantom of wrist was moved at 0, 2, 4, 6, 8, and 10 cm in the X-axis and Y-axis directions, respectively. For quantitative evaluation, the difference of distance between the radius and ulna was measured in picture archiving and communication system (PACS) system. As a qualitative evaluation, survey was conducted among 20 radiologic technologists who examined the Wrist PA-grip view. The Kruskal Wallis test was performed to compare the distortion according to the phantom movement in the X-axis and Y-axis directions based on the SID, and the Tukey test was performed as a post-test. In the quantitative evaluation results, the measured values obtained in the X-axis was not significantly different in all groups (p>0.05). The measured values obtained in the Y-axis was significantly different in the most groups (p<0.05). Therefore, to reduce distortion while maintaining image quality, we recommend what examine the SID at 150 cm than 110 cm.