• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1025-1033
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• 2011

This paper presents a realization of a peer-to-peer communication system for a UAV navigational monitoring using a commercial HSDPA(High Speed Download Packet Access) mobile communication device. The realized system consists of a communication server, an air data terminal and multiple ground monitoring devices, where the server transfers navigational data from a UAV to multiple monitoring devices in real-time with commercial HSDPA modem. Through ground and flight tests, data were obtained to observe the realized system. Test results show that, depending on communicational environment, about 300msec delay, congestion and packet-loss between air data terminal and ground monitoring devices. Nevertheless, through high-speed long range test on a ground vehicle and altitude test with a UAV flight, the feasibility of a UAV navigational monitoring system was observed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.75-81
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• 2012

With the advance of internet technology and fast growing of data volume, it become very hard to find a demanding information from the huge amount of data. Recommender system can solve the delema by helping a user to find required information. This paper proposes a reinforcement learning based hybrid recommendation system to predict user's preference. The hybrid recommendation system combines the content based filtering and collaborate filtering, and the system was tested using 2000 images. We used mean abstract error(MAE) to compare the performance of the collaborative filtering, the content based filtering, the naive hybrid filtering, and the reinforcement learning algorithm based hybrid filtering methods. The experiment result shows that the performance of the proposed hybrid filtering performance based on reinforcement learning is superior to other methods.

• Journal of the Korean Geotechnical Society
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• v.34 no.9
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• pp.19-32
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• 2018

In this study, the applicability and practicality of landslides monitoring by using wireless sensor network (WSN) was analysed. WSN system consists of a sensor node for collecting and transmitting data using IEEE 802.14e standard, a gateway for collecting data and transmitting the data to the monitoring server. In the topology of the sensor network, a highly flexible and reliable mesh type was adopted, and three testbeds were chosen in each location of Seoul metropolitan area. Soil moisture sensors, tensiometers, inclinometers, and a rain gauge were installed at each testbed and sensor node to monitor the landslide. For the estimation of the optimal network topology between sensor nodes, the susceptibility assessment of landslides, forest density and viewshed analysis of terrain were conducted. As a result, the network connection works quite well and measured value of the volumetric water content and matric suction simulates well the general trend of the soil water characteristic curve by the laboratory test. As such, it is noted that WSN system, which is the reliable technique, can be applied to the landslide monitoring.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1458-1464
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• 2007

Today, domestic and foreign manufacturing industries have to cope with obsolescence of manufacturing equipment because the shifting market trends drive the rapid changes in the production process resulting in stressful operation. Quality control process for manufacturing and production involves a familiar step - when the production process is completed, every item is subjected to various routine tests to determine that it meets the minimum quality standards. Typically, when a faulty product is found, the production line has to be stopped and the current batch is marked for further inspected and exhaustive testing. In this research, we propose a quality monitoring system for productivity enhancement. Our approach aims to reduces the operational down time in the production line of a car-component factory. The proposed monitoring system for productivity enhancement is designed to collect the data through testing at each phase of the assembly line and uses predictive methods on the collected data to achieve early detection of faults in the production process and minimize the number of products in a faulty batch thus minimizing the losses incurred from defective products. More importantly, this system aims to forecast and proactively detect faults and activate warnings when they are detected thus minimizing items in the defective batch, reducing the damage to manufacturing equipment and ultimately reducing the operational downtime or the delay in the resumption of normal factory operation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.725-728
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• 2009

This paper describes remote monitoring system for the various environments of a vinyl house, which was located in rural or outer of urban by use internet web connection system in a long distance office. We have constructed remote monitoring system by use a simple experimental model for the monitoring of various factors which need to operate common vinyl house. The experimental model includes temperature, humidity, smoke and infrared sensors for the measuring and AC 220V light bulb for the controlling in the USN system. Also, we have developed monitoring software by use NI Labview and communicate between PC and sensors through the DAQ-board, USN control board. We use CCD camera and grab board for the real time remote monitoring of wanted image in the house area. The computer server for remote connection is constructed in the local PC with Apache web server, PHP and MySQL ODBC. We construct internet communication system for the monitoring remotely the local environments of a vinyl house system.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.11a
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• pp.49-49
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• 2004

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1241-1246
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• 2005

This paper described an 8bit, 100Msample/s CMOS D/A converter using a glich-time minimization technique for the high-speed sampling rate of 100MHz level. The proposed DAC was implemented in 0,35um Hynix CMOS technology and adopts a current mode architecture to optimize sampling rate, resolution, chip area. The DAC linear characteristics was similar to the proposed specification the prototype error between DNL and INL is less than ${\pm}0.09LSB$ respectively. Also, fab-out chip was tested, analysed the cause of error operation, and proposed the field considerations for chip test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3060-3069
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• 2010

LBS is service technique to provide several service which are required to user by user's location information for mobile. This paper presents Auto_Test system of testing the mobility performance of mobile clients in wireless mobile networks. In spite of importance of mobility management, currently the study of mobility management is not enough, therefore we have developed modulated Auto_Test management system for resolve the mobility management. The proposed system is composed of distance-based monitoring, location-based monitoring, scenario management, mobility management and statistic management, it makes the control by individual module. Simulation results show that the proposed system outperforms the existing systems.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.47-53
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• 2020

There is a need for a system that provides early warning of presence and type of failure of automobile wheel bearings through the application of predictive fault analysis technologies. In this paper, we presented a sensor module mounted on a wheel bearing and a diagnostic system that collects, stores and analyzes vehicle acceleration information and vibration information from the sensor module. The developed sensor module and predictive analysis system was tested and evaluated thorough excitation test equipment and real automotive vehicle to prove the effectiveness.

• 전자공학회논문지 IE
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• v.43 no.3
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• pp.6-12
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• 2006

This paper described an 8bit, 100Msample/s CMOS D/A converter using a glitch-time minimization technique for the high-speed sampling rate of 100MHz level. The proposed DAC was implemented in $0.35{\mu}m$ Hynix CMOS technology and adopts a current mode architecture to optimize sampling rate, resolution, chip area. The DAC linear characteristics was similar to the proposed specification and the prototype error between DNL and INL is less than $\pm$0.09LSB respectively. Also, the manufactured DAC chip was analyzed the cause of error operation and proposed the field considerations for chip test.