• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.359-368
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• 2018

In this paper, a method is presented to identify the physical and modal parameters of multistory shear building based on substructural technique using block pulse generalized operational matrix and genetic algorithm. The substructure approach divides a complete structure into several substructures in order to significantly reduce the number of unknown parameters for each substructure so that identification processes can be independently conducted on each substructure. Block pulse functions are set of orthogonal functions that have been used in recent years as useful tools in signal characterization. Assuming that the input-outputs data of the system are known, their original BP coefficients can be calculated using numerical method. By using generalized BP operational matrices, substructural dynamic vibration equations can be converted into algebraic equations and based on BP coefficient for each story can be estimated. A cost function can be defined for each story based on original and estimated BP coefficients and physical parameters such as mass, stiffness and damping can be obtained by minimizing cost functions with genetic algorithm. Then, the modal parameters can be computed based on physical parameters. This method does not require that all floors are equipped with sensor simultaneously. To prove the validity, numerical simulation of a shear building excited by two different normally distributed random signals is presented. To evaluate the noise effect, measurement random white noise is added to the noise-free structural responses. The results reveal the proposed method can be beneficial in structural identification with less computational expenses and high accuracy.

• Journal of Biomedical Engineering Research
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• v.38 no.3
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• pp.129-136
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• 2017

The exoskeleton robot is a technology developed to be used in various fields such as military, industry and medical treatment. The exoskeleton robot works by sensing the movement of the wearer. By recognizing the wearer's daily activities, the exoskeleton robot can assist the wearer quickly and efficiently utilize the system. In this study, LDA, QDA, and kNN are used to classify gait types through kinetic data obtained from subjects. Walking was selected from general walking and stair walking which are mainly performed in daily life. Seven IMUs sensors were attached to the subject at the predetermined positions to measure kinematic factors. As a result, LDA was classified as 78.42%, QDA as 86.16%, and kNN as 87.10% ~ 94.49% according to the value of k.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.110-115
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• 2012

Satellite structure should be designed to accommodate and support safely the payload and equipments necessary for its own missions and to secure satellite and payloads from severe launch environments. The launch environments imposed on satellites are quasi-static accelerations, aerodynamic loads, acoustic loads and shock loads. Currently KARI(Korea Aerospace Research Institute) is developing Geo-KOMPSAT-2(Geostationary Earth Orbit KOrea Multi-Purpose Satellite) with technologies which were acquired during COMS(Communication, Ocean and Meteorological Satellite) development. As compared to COMS Geo-KOMPSAT-2 requires more propellant due to mass increase of Advanced Meteorological Payload with high resolution and increase of miss life, it is difficult to apply the design concept of COMS to Geo-KOMPSAT-2. This paper deals with conceptual design of Structural Subsystem for Geo-KOMPSAT-2.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.119-122
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• 2016

Feature detection is recognized as an accurate spectrum sensing approach when the information of the desired signal is partly known at the receiver. This type of detection was proposed to overcome large noise environment. Cyclostationary detection is an example of feature detection in spectrum sensing technique in cognitive radio. However, the cyclostationary process calculation requires a lot of processing time and information about the designed signals. On the other hand, energy detection spectrum sensing is widely known as a simple and compact spectrum sensing technique. However, energy detection is highly affected by large noise and lead to high detection error probability. In this paper, the combination of energy detection and cyclostationary is proposed in order to increase the accuracy and decrease the calculation and processing time. The two-layer threshold is utilized in order to reduce the complexity of computation and processing time in cyclostationary which can lead to the improved throughput of the system. The simulation result shows that the implementation of energy-based cyclostationary detector can help to improve the performance of the system while it can considerably reduce the required time for signal detection.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.18-23
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• 2016

Internet of things (IoT) is revolutionizing in the patient-Centered medical monitoring and management by authorizing the Smartphone application and data analysis with medical centers. The network connectivity is basic requirement to collect the observed human beings' health information from Smartphone to monitor the health from IoT medical devices in personal healthcare. The IoT environment built in Smartphone is very effective and does not demand infrastructure. This paper presents the smart phone deployed personal IoT architecture for Non-Invasive ECG Capturing. The adaptable IoT medical device cum Gateway is used for personal healthcare with big data storage on cloud configuration. In this approach, the Smartphone camera based imaging technique used to extract the personal ECG waveform and forward it to the cloud based big data storage connectivity using IoT architecture. Elaborated algorithm allows for efficient ECG registration directly from face image captured from Smartphone or Tablet camera. The profound technique may have an exceptional value in monitoring personal healthcare after adequate enhancements are introduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3832-3840
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• 2014

The rapidly aging population is also increasing the number of dementia patients rapidly. Studies have revealed the early signs of slowing progress. Therefore, dementia patient safety, continuous care, daily living, and health care are becoming more important. In this paper, a smart home care system using smart phones and Bluetooth communication technology was used to monitor the state of dementia patients of based on the results of grading dementia, health care of the dementia patients at home and provide for the safety of the system using motion sensors and gas leak sensors to respond to various emergency situations, such as fire, gas leak protection, and loitering. Using this system, the patient can stay longer in their home due to the nature of Korean culture before admission, while reducing the family's economical, physical and psychological burden and allowing the consultation of specialists through the system by building a database of individuals and providing professional service and specialty care referral agencies through the link.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.411-416
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• 2015

The service size of an IoT environment is determined by the various types of sensors. A gateway for relaying sensor information from various sensors is a representative middleware system, and an infographics showing the information with a graphical presentation of data and information is a client system for representing real-time information efficiently, it is necessary a similar test bed with IoT environment to develop a real-time infographics displaying a large amount of information effectively. The testing tools used in developing the existing network systems are mostly made to be suitable for functional testing and performance testing of the driven unit. In this paper, we proposed a mean which is web-based simulation framework to create a variety of information required for real-time infographics development, and evaluate the function of the system proposed by the test function of the comparison with the previous network test tool.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.319-326
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• 2009

In this paper, the key technologies of Navigation receiver for GNSS sensor station are presented as a development result of a GNSS ground station in ETRI. A wide-band antenna and RF/IF components and SW signal processing unit to cover the GPS and Galileo signals for GNSS receiver are developed and its performance is verified by using GPS live signal and GNSS RF signal simulator from SpirentTM. We also gather GIOVE-A signal by using H/W antenna and RF/IF units in IF-level as sampling frequency and bit number, 112MHz and 8bits, respectively by using the developed wide-band antenna and RF/IF components. Data acquisition is done by using commercial data acquisition device from National Instrument TM. The gathered data is fed into SW receiver to process Galileo E1 to verify Galileo signal processing by Galileo live signal from GIOVE-A.

• Journal of Information Technology Services
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• v.11 no.3
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• pp.161-175
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• 2012

A novel concept of ICT based service, which is called N-device service, is proposed and implemented in the form of N-device smart education services. The N-device services are different from the existing N-screen services in terms of the number of devices a user is using for a specific service at the same time. A N-device service consists of several smart devices which are different in size, software and hardware platform, mobility, manufacturer and the like by fully utilizing the characteristic of each device. The major and unique features of N-device services are analyzed and depicted in a strict way. Those are shared role for each device, service by configurable device, one sensor multiple use, real-time data sharing, role shifting and new market creation. It is turned out that the N-device service is more human centric compared with existing ICT based services and can give richer digital experience to users because non-existent services become possible with the new concept. However, there exist several barriers to be implemented and commercialized in the real world. Those include high development cost and time, small market and different application platforms of devices. These barriers can be overcome by technical advances and cooperation between relevant parties. The smart education is very prominent area, in which the novel concept can be applied with high priority because Korean government announced its plan to boost up new educational services with big budget and these are acceptable by enthusiastic Korean parents and students. That's why the N-device service is implemented in the education area, which is called as "livessam(live teacher)," with four smart devices, IPTV, tablet PC, PC and smart phone. By providing both detailed service scenario and techniques, we shows that the novel education service is technically feasible and acceptable by teachers and students.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.506-512
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• 2016

Recently, energy harvesting technology is considered as a tool to improve the lifetime of sensor networks by mitigating the battery capacity limitation problem. However, the previous work on energy harvesting has failed to provide practical information since it has assumed an ideal channel knowledge model with perfect channel state information at transmitter (CSIT). This paper proposes an energy efficient resource allocation scheme that takes account of the channel estimation process and the corresponding estimation error. Based on the optimization tools, we provide information on efficient scheduling and power allocation as the functions of channel estimation accuracy, harvested energy, and data rate. The simulation results confirm that the proposed scheme outperforms the conventional energy harvesting networks without considering channel estimation error in terms of energy efficiency. Furthermore, with taking account of channel estimation error, the results provides a new way for allocating resources and scheduling devices.