• Journal of Power Electronics
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• v.19 no.5
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• pp.1171-1181
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• 2019

Modular Multilevel Converter (MMC)-based HVDC power transmission using a real-time simulator is one of the key technologies in power electronics research. This paper introduces the design methodology of a physical MMC-HVDC control system based on a Field-Programmable Gate Array (FPGA), which has the advantage of high-speed parallel operation, and validates the accuracy of MMC-HVDC control when operated with a Real-Time Digital Simulator (RTDS). Finally, this paper compares and analyzes the characteristics of capacitor voltage balancing methods such as Nearest Level Control (NLC), NLC with a reduced switching frequency, and tolerance band modulation implemented on physical control system.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.11-19
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• 2020

IoT has been consistently used in various fields such as smart home, wearables, and healthcare. Since IoT devices are small terminals, relatively simple wireless communication protocols such as IEEE 802.15.4 and ISO 18000 series are used. In this paper, we designed the 802.15.4q 2.4 GHz TASK physical layer. Physical protocol data unit of TASK supports bit-level interleaving and shortened BCH encoding. It is spread by unique ternary sequences. There are four spreading factors to choose the data rate according to the communication channel environment. The TASK physical layer was designed using verilog-HDL and verified through the loop-back test of the transceiver. The designed TASK physical layer was implemented in a fpga and tested using MAXIM RFICs. The PER was about 0% at 10 dB SNR. It is expected to be used in small, low power IoT applications.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.2
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• pp.219-230
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• 2002

One of the most important functions digital libraries need to offer is to help users find necessary information in a distributed environment in the most efficient and effective manner. In order to meet the goal, it is desirable to link scattered pieces of information and present them as a logically coherent whole when the user wants it, so that he or she doesn't need to know their physical location. The virtual document is an integrated document that the total or part of the physical documents stored in a specific repository are linked dynamically. Our MIRAGE-III digital library system provides a content-based retrieval of physical documents and the virtual documents in XML. This system provides a retrieval of partial documents, attributes and hierarchical structures and linked-documents based in structured documents like XML or SGML. In this paper we describe a methodology of design and implementation of the query processor and retrieval server in the MIRAGE-III digital library system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3747-3765
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• 2017

Existing authentication mechanisms in cellular mobile communication networks are realized in the upper layer by employing cryptographic techniques. Authentication data are broadcasted over the air in plaintext, enabling attackers to completely eavesdrop on the authentication and get some information about the shared secret key between legitimate nodes. Therefore, reusing the same secret key to authenticate several times results in the secret key's information leakage and high attacking rate. In this paper, we consider the most representative authentication mechanism, Authentication and Key Agreement (AKA), in cellular communication networks and propose an enhanced AKA scheme based on Physical Layer Authentication (AKA-PLA). Authentication responses generated by AKA are no longer transmitted in plaintext but masked by wireless channel characteristics, which are not available to adversaries, to generate physical layer authentication responses by a fault-tolerant hash method. The authenticator sets the threshold according to the authentication requirement and channel condition, further verifies the identity of the requester based on the matching result of the physical layer authentication responses. The performance analyses show that the proposed scheme can achieve lower false alarm rate and missing rate, which are a pair of contradictions, than traditional AKA. Besides, it is well compatible with AKA.

• Physical Therapy Korea
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• v.15 no.3
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• pp.62-69
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• 2008

The purpose of this study was to measure intrarater and interrater reliability of a portable digital pressure algometer. Fifty healthy subjects were recruited for this study. Pressure pain thresholds of splenius capitis, levator scapular, and upper trapezius muscles were measured using by FPK algometer and portable digital pressure algometer. Three trials were done on each subject by two examiners. Intraclass correlation coefficients (ICCs) were used to determine the reliability of each measure. The intrarater reliability of the FPK algometer was good and excellent (ICC .63~.79) and the interrater reliability was poor and good (ICC .15~.57). The intrarater reliability of a portable digital pressure algometer was excellent (ICC .75~.86) and the interrater reliability was poor and good (ICC .35~.61). This result suggests that the intrarater reliability and interrater reliability of a portable digital pressure algometer were better than an FPK algometer.

• Journal of Digital Contents Society
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• v.18 no.3
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• pp.577-584
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• 2017

Despite growing participation of many researchers, the cases of applying the transformative emotional display technology using physical materials and media are still in its early stages and the concept and structure are not properly established in Korea. The emerging global trend of physical display shows a possibility of new digital signage using emotional flip display. In this context, this study attempts to develop related element technology necessary in physical flip display and electromagnetic rotation module along with the integration platform of aesthetic arbitrarily-shaped display. The found results will be applied in researching the contents for the main subject which will be exhibited at the EXPO 2017 in Astana. It is to build up the foundation pioneering the localization of associated industry by means of diverse technological breakthroughs including flip-display technology, electromagnetic module technology, real-time video inter-working technology, high-speed rotation module technology, and transformative 3D frame technology.

• The korean journal of orthodontics
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• v.46 no.1
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• pp.13-19
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• 2016

Objective: The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods: CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results: Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were $0.41{\pm}0.305%$ and $0.45{\pm}0.456%$, respectively; for anterior Bolton ratios, $0.59{\pm}0.520%$ and $1.01{\pm}0.780%$, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Conclusions: Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.39-47
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• 2010

As various materials and new methods can be used due to developments in science and expansion of thinking, modern architectural color composes extensive possibilities exceeding its physical role of the past. In particular, rather than the initial external expression, the secondary connotative interpretation is more important in interpreting architectural color. This is because color interpretation changes the meaning of space based on light. Also, the development of digital technology has shifted the use of architectural color from passive realization to a more proactive concept and value. In other words, such shift leads to a new discussion on architectural color such as non-representation, invisibility, and non-physicality as the concept of fixed time, space and movement has been weakened. This paper begins by conceptualizing the digital space, a term widely used to interpret the architectural color of digital space. And it will be categorized as non-representational architectural color, invisible architectural color, and non-physical architectural color, by combining the characteristics of digital space with the modern architecture's color examples. Digital space overcoming the space time is differently interpreted from the past color expression. Modern architecture's color which substitutes the passive view with active body takes a role delivering various axes of discussions with synaesthesia.

• World Technopolis Review
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• v.8 no.2
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• pp.120-134
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• 2019

The main objective of this study was to investigate the customer's satisfaction level with the digital relationship model of Banco do Brasil Exclusive Business Offices situated in Rio Grande do Sul. Banco do Brasil is one of the largest Brazilian and global financial institutions and conducted a restructuring customer's relationship model since 2015, creating new specific service structures for certain segments, among them exclusive offices. This research had a qualitative step with an internal documentary analysis about the company and a semi-structured interview with manager's offices, in order to check the strategy and the foundations of business model, as well as identify perceptions and the difficulties in implementing this new structure. The quantitative step held the findings about customer satisfaction level in relation to the quality of services provided by offices, through an electronic survey based on the Servqual Scale developed by Parasuraman et al. (1988), which measures the difference between customer's expectations and perception in five dimensions: tangibility, reliability, understanding, safety and empathy. The results shown that Banco do Brasil customers' are satisfied with services offered through the digital model and the new business structure, in which is offered a humanized service together with the best technology. It was found, also, that digital probably would not replace the physical world, but they complement one another. Digital offices and physical agencies will coexist, improving value proposition delivery and better customers experience, satisfy them and build their loyalty.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.123-132
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• 2017

The physical display technology is the ultimate display technology that human beings aspire, and the world makes use of laser, plasma and reflector plate. Besides, technology development of binocular stereoscopic display has been actively progressed, but there is a limitation to the intact physical representation such as influence of optical ambient light and brightness. In this paper, the display technology using physical deformation different from the existing optical display is approached as a cultural and emotional perspective. The purpose of this paper is to develop the multivariate display technology that can create 3D realistic stereoscopic images through projecting dynamic images on physically diversified screen by overcoming the limitations of 2D planar digital signage and study how to apply them to video, exhibition and performance.