• 한국가시화정보학회지
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• 제15권3호
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• pp.14-19
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• 2017

Increase of blood viscosity significantly changes the flow resistance and wall shear stress which are related with cardiovascular diseases. For measurement of blood viscosity, microfluidic method has proposed by monitoring pressure between sample and reference flows in the downstream of a microchannel with two inlets. However, it is difficult to apply this method to unknown flow conditions. To measure blood viscosity under unknown flow conditions, a microfluidic method based on micro particle image velocimetry(PIV) is proposed in this study. Flow rate in the microchannel was estimated by assuming velocity profiles represent mean value along channel depth. To demonstrate the measurement accuracy of flow rate, the flow rates measured at the upstream and downstream of a T-shaped microchannel were compared with injection flow rate. The present results indicate that blood viscosity could be reasonably estimated according to shear rate by measuring the interfacial width and flow rate of blood flow. This method would be useful for understanding the effects of hemorheological features on the cardiovascular diseases.

• 전자공학회논문지S
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• 제35S권2호
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• pp.70-78
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• 1998

Spike detection in long-term EEG monitoring forepilepsy by wavelet transform(WT), artificial neural network(ANN) and the expert system is presented. First, a small set of wavelet coefficients is used to represent the characteristics of a singlechannel epileptic spikes and normal activities. In this stage, two parameters are also extracted from the relation between EEG activities before the spike event and EEG activities with the spike. then, three-layer feed-forward network employing the error back propagation algorithm is trained and tested using parameters obtained from the first stage. Spikes are identified in individual EEG channels by 16 identical neural networks. Finally, 16-channel expert system based on the context information of adjacent channels is introducedto yield more reliable results and reject artifacts. In this study, epileptic spikes and normal activities are selected from 32 patient's EEG in consensus among experts. The result showed that the WT reduced data input size and the preprocessed ANN had more accuracy than that of ANN with the same input size of raw data. Ina clinical test, our expert rule system was capable of rejecting artifacts commonly found in EEG recodings.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1138-1142
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• 2005

The tidal river is a river affected by tide, which causes the water level to rise and fall two times everyday periodically. The local velocity across the river could be very fast because of the cross-sectional characteristics of the river even though it's not a rainy season. Therefore extreme local scour could take place around hydraulic structures such as piers and caissons due to backward flow velocity. For the construction of pier foundation of Ilsan-bridge In the Han River, the field observations were performed to get the velocity and water level. The numerical analysis was performed by HEC-RAS(UNET). The relationship between measured maximum velocity and calculated mean velocity is achieved, which is used to estimate the velocity and water level as the construction is proceeding. Countermeasures for scour were designed with the results of the hydraulic analysis to avoid potential damage during construction work. According to the results of monitoring, the velocity increase after temporary road embankment was negligible, from which it is considered that the degradation of main channel compensated for the constriction of cross-section by embankment.

• 전기학회논문지
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• 제67권10호
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• pp.1382-1387
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• 2018

There is a high demand for energy efficiency improvement of factories that make up a large part of national electric energy. Therefore, research on smart FEMS technology for monitoring, analyzing and controlling energy consumption patterns is under way, but there is still a lack of research on detailed element technology for communication and control inside the factory. In this paper, we proposed OFDM VLC system based on MODBUS protocol for communication between gateways, sensors, and devices to implement smart FEMS in indoor factory environment. Assuming a conveyor belt load control, we validated the proposed system by simulating the inverter motor control and checking the performance.

• 전기학회논문지P
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• 제64권3호
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• pp.138-142
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• 2015

Most of the existing studies on functional safety testing for the railway signaling system software have focused on verifying the functional safety through the monitoring of internal memory embedded railway signaling system. However, the railway signaling system is one of the typical embedded control system in the railway sector, and the embedded software has a characteristic of generating an appropriate outputs through the combination of internal processing in consideration of the current internal status and external input. Therefore, the test approach of using the interface communication channel can be effective way for the functional testing for railway signaling system software in consideration of these characteristic. Since a communication interface specification of the railway signal system has a the properties of the sequence input and output signals, test-case for software testing is the most effective methodology by MSC (Message Sequence Chart) language, one of the graphic language. The MSC-based test-case generating methodology for signaling system software was proposed in this paper.

• 지식경영연구
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• 제16권4호
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• pp.35-45
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• 2015

Fintech, which means the convergence of finance and information technology, becomes a hot topic in the financial sector. Through innovative activities on financial services, ICT(Information and Communication Technology) is integrated into the overall financial industry, and a new form of financial services could be expected to improve the existing financial system. On the other hand, fintech services are relatively vulnerable to security issues. Due to the process simplication and the channel fusion, the leakage of personal and financial informations, authentication bypass, phishing, and pharming are getting more concerned. In this study we investigated the security risk of fintech services in the viewpoints of service provider, technology adoption, and security policy. The possible countermeasures to reduce those risks are suggested because security is an important criterion for selecting financial services. This study basically offers quantification of the potential security risks and step-by-step control measures about business processes in the fintech services. The suggested security model includes user authentication, terminal security, payment information protection, API(Application Programming Interface) security, and abnormal transaction monitoring. This study might contribute to an understanding of the security risks and some possible measures for mitigating those risks on the practical perspective.

• 한국대기환경학회지
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• 제27권3호
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• pp.326-336
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• 2011

The Light Detection and Ranging (Lidar) observation provides a specific knowledge of the temporal and vertical distribution and the optical properties of the aerosols. Unlike typical Mie scattering Lidars, which can measure backscattering and depolarization, the Raman Lidar can measure the quartz signal at the ultra violet (360 nm) and the visible (546 nm) wavelengths. In this work, we developed a method for estimating mineral quartz concentration immersed in Asian dust using Raman scattering of quartz (silicon dioxide, silica). During the Asian dust period of March 15, 16, and 21 in 2010, Raman lidar measurements detected the presence of quartz, and successfully showed the vertical profile of the dust concentrations. The satellite observations such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) confirmed spatial distribution of Asian dust. This approach will be useful for characterizing the quartz dominated in the atmospheric aerosols and the investigations of mineral dust. It will be especially applicable for distinguishing the dust and non-dust aerosols in studies on the mixing state of Asian aerosols. Additionally, the presented method combined with satellite observations is enable qualitative and quantitative monitoring for Asian dust.

• 한국물환경학회지
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• 제26권3호
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• pp.474-481
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• 2010

This study was conducted to describe the characteristics of Non-point source (NPS) Pollution discharge from a coal mining area in Korea. The study areas is located on the Dogye site, Samchuk, Kangwon Province Coal Corporation and the Jangsung site, Taebaek, Kangwon Province Coal Corporation. The monitoring system was installed at a drainage channel and water samples and rainfall events were collected during March 2008 to February 2009. The collected water samples were analyzed with respect to SS, BOD, $COD_{Cr}$, $COD_{Mn}$, T-N, T-P, and TOC, respectively. It was observed that the runoff and water quality were largely influenced by mine drainage. Also a significant relationship was observed from the correlation between flow and water quality, flow and NPS. And estimated Event Mean Concentration (EMC), NPS pollution loads were Dogey coal mine and Taeback coal mine respectively. As the study progresses in the future, runoff and pollution loads will be updated.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.720-725
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• 2008

This paper proposes a system architecture for USN with a service robot to provide more active assisted living services for elderly persons by monitoring their mental and physical well-being with USN environments at home, hospital, or silver town. Sensors embedded in USN are used to detect preventive measures for chronic disease. Logged data are transferred to main controller of a service robot via wireless channel in which the analysis of data is performed. For the purpose of handling emergency situations, it needs real-time processing on gathering variety sensor data, routing algorithms for sensor nodes to a moving sink node and processing of logged data. This paper realized multi-hop sensor network to detect user movements with biometric data transmission and performed algorithms on Xenomai, a real-time embedded Linux. To leverage active sensing, a mobile robot is used of which task was implemented with a priority to process urgent data came from the sink-node. This software architecture is anticipated to integrate sensing, communication and computing with real-time manner. In order to verify the usefulness of a proposed system, the performance of data transferring and processing on a real-time OS with non real-time OS is also evaluated.

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.1-18
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• 2015

Traditionally, it is not easy to carry out tests to identify modal parameters from existing railway bridges because of the testing conditions and complicated nature of civil structures. A six year (2007-2012) research program was conducted to monitor a group of 25 railway bridges. One of the tasks was to devise guidelines for identifying their modal parameters. This paper presents the experience acquired from such identification. The modal analysis of four representative bridges of this group is reported, which include B5, B15, B20 and B58A, crossing the Caraj$\acute{a}$s railway in northern Brazil using three different excitations sources: drop weight, free vibration after train passage, and ambient conditions. To extract the dynamic parameters from the recorded data, Stochastic Subspace Identification and Frequency Domain Decomposition methods were used. Finite-element models were constructed to facilitate the dynamic measurements. The results show good agreement between the measured and computed natural frequencies and mode shapes. The findings provide some guidelines on methods of excitation, record length of time, methods of modal analysis including the use of projected channel and harmonic detection, helping researchers and maintenance teams obtain good dynamic characteristics from measurement data.