• Journal of IKEEE
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• v.22 no.2
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• pp.510-513
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• 2018

Recently, EMC (electromagnetic compatibility) becomes very important, which demands the measurement of EMI (electromagnetic interference) in the chip level. NFS (near-field scanning) systems defined in IEC 61967 and IEC 62508 are typical methods to analyze EMI in the chip level. As chips becomes faster, frequency measurement of NFS system should become wideband, but it degrades SNR (singal-to-noise ratio) of the NFP (near-field probe). This paper surveys SNR enhancement technologies of the NFS while maintaining wideband characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.879-885
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• 2014

In this paper, we designed and fabricated wideband 3-axis isotropic antenna for the Electro-Magnetic Fields(EMFs) measurement. Each part of proposed 3-axis antenna has isotropic characteristics and arbitrary axis of proposed 3-axis antenna could be selectable using RF switch. Also, a resistor was inserted in each axis of proposed 3-axis antenna for improving antenna gain and noise suppression characteristics, and port impedance of each dipole antenna were matched by balun. For the performance verification of antenna, GTEM Cell which generates standard electromagnetic field was used for the derivation of antenna factor and receiver sensitivity. As a result, fabricated 3-axis isotropic antenna has receiver sensitivity of 0.12~4.2 mV/m and typical VSWR of 3.3:1 within a wide operation frequency range from 0.03 MHz to 3 GHz.

• Structural Monitoring and Maintenance
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• v.3 no.1
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• pp.91-114
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• 2016

In this paper, recent research trends and activities on structural health monitoring (SHM) of civil infrastructure in Korea are reviewed. Recently, there has been increasing need for adopting smart sensing technologies to SHM, so this review focuses on smart sensing, monitoring, and assessment for civil infrastructure. Firstly, the research activities on smart sensor technology is reviewed including optical fiber sensors, piezoelectric sensors, wireless smart sensors, and vision-based sensing system. Then, a brief overview is given to the recent advances in smart monitoring and assessment techniques such as vibration-based global monitoring techniques, local monitoring with piezoelectric materials, decentralized monitoring techniques for wireless sensors, wireless power supply and energy harvest. Finally, recent joint SHM activities on several test beds in Korea are discussed to share the up-to-date information and to promote the smart sensors and monitoring technologies for applications to civil infrastructure. It includes a Korea-US joint research on test bridges of the Korea Expressway Corporation (KEC), a Korea-US-Japan joint research on Jindo cable-stayed bridge, and a comparative study for cable tension measurement techniques on Hwamyung cable-stayed bridge, and a campaign test for displacement measurement techniques on Sorok suspension bridge.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2531-2546
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• 2021

For several years, virtual reality (VR) and augmented reality (AR) technologies have been improving. However, some hurdles remain that slow down the distribution of VR and AR devices, such as head-mounted display (HMD), and related consumer content. One issue is VR motion sickness, which has been experienced by users using 360 degree VR content via HMD. This paper discusses the related international standardization work that classifies the factors causing VR sickness, and proposes the process for VR sickness level evaluation. Among the factors causing VR sickness, many research institutes regard minimizing MTP (Motion-to-Photon) latency as the key enabler to mitigate VR sickness. Thus, this paper introduces research trends of MTP latency measurement and MTP latency mitigation. This paper categorizes the research on MTP latency measurement into 2 categories of hardware-based approach and software code-level approach. The 2 approaches have different pros and cons depending on use-case, purpose, and architecture of each multimedia system. The pros and cons are addressed in this paper. Additionally, the research on mitigating MTP latency with diverse strategies such as proactive computing, caching, and edge server technology is explained, and compared to conventional technologies, shows improved performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.379-381
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• 2021

As information and communication technologies develop, many studies are being conducted to maintain an efficient production environment by applying network and computing technologies to existing production systems. Unlike classical control systems, these smart production systems need to collect data about the production environment in real time, and operate fluidly as it changes. In this paper, we present a measurement system that can collect data in real time through network-based sensors and respond effectively to environmental changes. We also proved this smart system can cope with external environmental changes and maintain an effective production environment.

• Journal of Korean Society for Quality Management
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• v.51 no.3
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• pp.435-444
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• 2023

Purpose: To attain advanced performance certification, safety aspects along with functionality and performance are essential. Hence, this study suggests radiation leakage assessment methods for aviation security equipment during its performance certification. Methods: Detection technology guided the choice of radiation leakage assessment targets. We then detailed measurement and evaluation methods based on equipment type and operation mode. Equipment was categorized as container or box types for establishing measurement procedures. Results: We've developed specific radiation leakage assessment procedures for different types of aviation security equipment, crucial for ensuring airport safety. Using these procedures allows efficient evaluation of compliance with radiation leakage standards. Conclusion: The suggested radiation leakage assessment method aims to enhance aviation security and reliability. Future research will focus on identifying risks in novel aviation security equipment detection technologies and establishing safety standards.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.491-499
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• 2011

The objective of this study was to develop the export strategic core technologies for IT fusion next generation agricultural machines by the analysis of comprehensive and cooperative systems of industries, universities, and institutes. In order to achieve the objective of this study, an expert panel was formed and operated. The first survey was conducted by the Delphi method. For this the export strategic core technologies were surveyed and analyzed using the questionnaire. Based on the results of the first survey, the second survey was conducted. The questionnaire used for the second survey was designed by results of the first survey. The results of the second survey was analyzed by AHP method. The third survey was conducted based on the second one, and the final results were analyzed and the export strategic core technologies were developed through the expert meeting. The study results showed six export strategic core technologies as the followings : 1) environment-friendly engine technology for high performance 2) high performance/high efficiency power transmission system technology 3) development of measurement system technology for safety of agricultural products 4) field application of sensor networks 5) large size combine development technology for high performance 6) quality evaluation technology for agricultural products.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1155-1164
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• 2011

In this paper, we proposed the transmit beam measurement method of active phased array antenna, which is installed in Korea's first developed naval medium range radar, using near-field measurement facility. The pulse-mode high power characteristics of active phased array antenna's trasmit-beam make it difficult to measure with general near-field measurement facilities where low power continuous RF signals are used. Thus, in this paper, the measurement method of active phased array antenna's transmit beam in conjunction with the near-field measurement facility, which is suitable for the high-power transmit beam measurement, and PNA-X network analyzer(Agilent Technologies), which can support pulse-mode measurement, was proposed and measured by near-field measurement techniques. And the EIRP(Effective Isotropic Radiated Power), the transmit characteristic of active phased array antenna, was measured by the near field measurement techniques and compared to numerical estimation which was nearly equal with small difference of 0.1 dB.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.562-572
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• 2015

$NO_x$ emissions from diesel vehicles have been regarded as a main cause of high $NO_2$ concentration in metropolitan area. Recent studies have shown that the on-road $NO_x$ emissions of diesel vehicles are quite higher than the emission limits specified with the pre-defined test method for emission certification. To reduce air pollutants effectively, the discrepancy of emissions in certification and real-driving conditions should be tackled. In this study, the real-driving emissions have been estimated with portable emission measurement system (PEMS). The results of this study have shown that the on-road $NO_x$ emissions from diesel vehicles have been decreased as the introduction of stricter emission regulation, EURO-6, but additional reduction should be still required and robust technologies should be applied to control $NO_x$ in real-driving conditions. RDE-LDV (Real Driving Emission - Light Duty Vehicles) test method being developed in the European Union can represent excessive on-road $NO_x$ emissions of diesel vehicles as applied emission technologies and can be a solution to remove discrepant $NO_x$ emissions between certification and Korean real-driving conditions. Among the $NO_x$ reduction technologies for EURO-6 diesel vehicles, selective catalytic reduction (SCR) system has shown the better performance than lean $NO_x$ trap (LNT) system to control on-road $NO_x$ emissions. Implementing RDE-LDV will require vehicle manufacturers to adopt the more effective $NO_x$ reduction technology in real driving conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.763-778
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• 2022

In this study we aim to identify the core technologies that play central roles along with the peripheral technologies that contribute to the technology convergence in digital healthcare. A total of 376 korean-patents related to healthcare were gathered from 2011 to 2020, and a topic modeling technique and a network analysis were conducted on the collected data. Six major topics were derived through the topic modeling procedure which are "data collection", "signal measurement", "health management", "data transmission", "diagnostic treatment", and "measurement device". Each of the six topics were analyzed to depict relations among technologies, specify the convergence characteristics, and identify the core-technology through centrality analysis. The study illustrates the present status of digital healthcare technology development and the technological convergence in South Korea and is anticipated to help establish policies to foster healthcare industry.