• Journal of the Korea Institute of Building Construction
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• v.22 no.6
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• pp.651-662
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• 2022

The electrochemical impedance spectroscopy(EIS) method was used to evaluate the concrete deterioration process related to chloride-induced steel corrosion with various corrosion levels(initiation, rust propagation and acceleration periods). The impressed current technique, with four total current levels of 0C, 13C, 65C and 130C, was used to accelerate steel corrosion in concrete cylinder samples with w/c ratio of 0.4, 0.5, and 0.6, immersed in a 0.5M NaCl solution. A series of EIS measurements was performed to monitor concrete deterioration during the accelerated corrosion test in this study. Some critical parameters of the equivalent circuit were obtained through the EIS analysis. It was observed that the charge transfer resistance(R_c) dropped sharply as the impressed current increased from 0C to 13C, indicating a value of approximately 10kΩcm². However, the sensitivity of R_c significantly decreased when the impressed current was further increased from 13C to 130C after corrosion of steel had been initiated. Meanwhile, the double-layer capacitance value(C_dl) linearly increased from 50×10^-6μF/cm² to 250×10^-6μF/cm² as the impressed current in creased from 0C to 130C. The results in this study showed that monitoring C_dl is an effective measurement parameter for evaluating the progress of internal concrete damages(de-bonding between steel and concrete, micro-cracks, and surface-breaking cracks) induced by steel corrosion. The findings of this study provide a fundamental basis for developing an embedded sensor and signal interpretation method for monitoring concrete deterioration due to steel corrosion at various corrosion levels.

• Journal of Korea Multimedia Society
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• v.21 no.5
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• pp.583-591
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• 2018

With the development of ICT(Information and Communication Technology), the number of smart devices is rapidly increasing. LBS(Location Based Service) applications that provide user's location based service are used in various fields. There is also a growing demand for indoor precision positioning technology to provide seamless services. In this paper, we propose an indoor positioning system that estimates the location of a smartphone user. The proposed algorithm determines whether the received signal is LOS(Line-of-Sight) or NLOS(Non-Line of-Sight) in order to decrease multipath effect by the indoor environment. The proposed positioning algorithm is very simple and requires only the AP(Access Point) coordinates. In addition, it requires only two APs for estimating the location of a smartphone user. The proposed algorithm is a practically applicable technology without any additional hardware and kernel modification in the smartphone. In the experiment results, the reliability of the positioning system was found to be within 0.83 m.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.637-658
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• 2015

The development of multimedia applications has followed the development of high-speed networks. By improving the performance of mobile devices, it is possible to provide high-transfer-speed broadband and seamless mobile multicasting services between indoor and outdoor environments. Multicasting services support efficient group communications. However, mobile multicasting services have two constraints: tunnel convergence and handoff latency. In order to solve these problems, many protocols and handoff methods have been studied. In this paper, we propose inter local mobility anchor (inter-LMA) optimized handoff model for mobile multicasting services in proxy mobility IPv6 based (PMIPv6-based) networks. The proposed model removes the tunnel convergence issue and reduces the router processing costs. Further, it the proposed model allows for the execution of fast handoff operations with adaptive transmission mechanisms. In addition, the proposed scheme exhibits low packet delivery costs and handoff latency in comparison with existing schemes and ensures fast handoff when moving the inter-LMA domain.

• Korean Journal of Materials Research
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• v.28 no.3
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• pp.159-165
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• 2018

In order to increase the efficiency of the sputtering method widely used in thin film fabrication, a dc sputtering apparatus which supplies both high frequency and magnetic field from the outside was fabricated, and cobalt thin film was fabricated using this apparatus. The apparatus can independently control the applied voltage, the target-substrate distance, and the target current, which are important parameters in the sputtering method, so that a stable glow discharge is obtained even at a low gas pressure of $10^{-3}$ Torr. The fabrication conditions using the sputtering method were mainly performed in $Ar+O_2$ mixed gas containing about 0.6 % oxygen gas under various Ar gas pressures of 1 to 30 mTorr. The microstructure of Co thin films deposited using this apparatus was examined by electron diffraction pattern and X-ray techniques. The magnetic properties were investigated by measuring the magnetization curves. The microstructure and magnetic properties of Co thin films depend on the discharge gas pressure. The thin film fabricated at high gas pressure showed a columnar structure containing a large amount of the third phase in the boundary region and the thin film formed at low gas pressure showed little or no columnar structure. The coercivity in the plane was slightly larger than that in the latter case.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.506-507
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• 2017

최근 의료영상진단기기 개발 동향은 ICT 기술과 접목하는 융합진단 영상기기 개발연구로 활발하게 진행되고 있다. 특히, 수술중 CT의 개발은 임상적 미수요 충족을 위한 최첨단 기술개발로 위급한 환자를 의료영상 촬영을 위한 지정장소로 이동해야하는 문제점을 해결하여 현장 어느 곳에서 촬영할 수 있고, 환자의 다양한 의료영상을 융합하여 환자의 병변에 대한 명확한 위치와 형태 그리고 상태를 파악할 수 있도록 하며 수술을 위한 네비게이션 기능을 포함한다. 본 논문에서는 수술중 CT에 대한 설계한 사항에 대해 기술하고자 한다. 제안한 시스템의 개발은 다양한 임상현장에서 신속하게 진단과 수술을 지원할 수 있을 것으로 기대하고 있다.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.379-388
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• 2013

u-Healthcare integration between ICT and healthcare service is able to utilize effectively for people's healthcare anywhere and any time. The purpose of this study is to explore the perception and influence factors on intention to use u-Healthcare service of physicians and staffs working for medical institutions. Ninety eight(98) valid cases have been collected for this study. It is also analysed by SPSS 18.0 and SmartPLS 2.0M3. Empirical findings provide important insights as follows: firstly, performance expectation, effort expectation and social influence positively influence intention to use u-Healthcare service; secondly, perceived risk negatively influences usage intention, and finally, performance expectation, effort expectation and perceived risk are moderated by voluntariness.

• Electronics and Telecommunications Trends
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• v.28 no.5
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• pp.111-121
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• 2013

인쇄전자(printed electronics) 기술은 인쇄가 가능한 기능성 전자 잉크 소재를 이용하여 초저가격의 프린팅 공정을 통해서 다양한 전자소자를 제작하는 기술로써, 차세대 ICT 기기의 제작에 적합한 전자제품을 생산하는데 적합한 공정기술로 잘 알려져 있다. 현재 인쇄전자의 기술수준은 일부 요소 부품들을 제작하고 간단한 전자회로를 구현하는 수준에 머무르고 있으나, 도체, 반도체, 절연체의 여러 잉크 소재 및 다양한 초미세 인쇄공정 기술의 개발이 진행됨에 따라 향후 폭넓은 분야에 적용될 것으로 기대된다. 이러한 인쇄전자의 관련 기술 중에서 최근 삼차원(3D) 프린팅 기술이 부상하고 있는데, 지난해 Economist에서는 3D 프린팅을 제3차 산업혁명을 가져올 기술 중 하나로 소개했으며, 세계경제포럼(WEF: World Economic Forum)에서는 2013년 10대 유망 기술 중 하나로 선정했다. 올해 초, 미국의 오바마 대통령은 국정연설에서 거의 모든 제품의 생산 방식을 바꿀 수 있는 잠재력을 가진 기술로 3D 프린팅을 언급했고, Optomec에서는 전자소자용 3D 프린팅 기술을 선보였다. 본 논문에서는 최근에 많이 연구되는 모바일용 무선통신소자나 차세대 디스플레이 백플레인용의 인쇄전자 기술과 상품의 모형인 목업(Mock-up)을 제작할때뿐 만 아니라 전자소자 제작에도 적용이 가능한 3D 프린팅 기술에 대하여 논하고자 한다.

• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.92-101
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• 2020

Artificial intelligence (AI) has become the hottest topic in information and communications technology (ICT) in recent years. Along with the advancement of AI technology, technologies such as big data, cloud, and high-speed wired and wireless communication are being applied to existing media areas in earnest, affecting all parts of the media value chain from content production to consumption. AI technology is now spreading across the media industry faster than any other industry. In the future, the gap between those with and without AI technology will widen, further deepening the polarization of the media ecosystem. Media intelligence, which combines media and AI technologies, is now perceived as essential, not optional. In this paper, we examine the current status of technology development and standardization by major domestic and foreign institutions on how AI is being utilized in the media industry. In addition, we discuss what technology should be developed to lead media intelligence.

• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.111-121
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• 2016

The plant equipment usually has a long life cycle. During its O&M (Operation & Maintenance) phase, since the occurrence of an accident of offshore plant equipment causes catastrophic damage, it is necessary to make more efforts for managing critical offshore equipment. Nowadays due to the emerging ICTs (Information Communication Technologies) and sensor technologies, it is possible to gather the health status data of important offshore equipment and their environment data, which leads to much concern on CBM (Condition-Based Maintenance). In this study, we will propose an approach to estimate the remaining lifetime of an offshore plant equipment (pump tower) based on gathered ocean environment data.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.651-652
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• 2016

최근 스포츠 과학과 ICT 기술을 접목하여 스포츠 활동올 분석하고자 하는 시도가 증가하고 있다. 이런 양상은 축구 경기에 대한 분석에서도 나타나고 있으며, 그 목적에 따라 다양한 방법으로 분석을 시도한 사례를 쉽게 발견 할 수 있다. 하지만, 현재까지 제시된 시스템들은 높은 수준의 경기 내용 분석올 제공하려는 시도를 보이지 않고 있다. 본 논문은 통계 분석 위주의 현재 축구 분석 시스템의 한계에 대해 논한 후 이를 내용 이해 기반으로 끌어올리기 위한 시스템의 구성 방법에 대한 구체적인 안을 제시하였다. 제안하는 시스템의 개발을 통하여 새로운 양상의 서비스와 산업 생태계 측면의 긍정적 변화를 기대할 수 있다.