• Broadcasting and Media Magazine
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• v.11 no.1
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• pp.68-77
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• 2006

The Cognitive Radio (CR) technology is a promising solution for exploiting the limited spectrum resources and providing flexibility of spectrum usage. Future interactive broadcasting service can be realized by utilizing CR concept, since the up-link return channel can be found by the spectrum sensing method, which is core functional block of the CR system. In this paper, the spectrum sensing technologies of CR system is presented. First the system architecture of the CR with spectrum sensing block is presented. The suggested spectrum sensing technique consists of the coarse and the fine spectrum sensing. The coarse spectrum sensing technique adopted the wavelet transform to provide the multi-resolution sensing feature - Multi-Resolution Spectrum Sensing (MRSS). The fine spectrum sensing technique uses the beneficial properties of the autocorrelation function Analog Auto-Correlation (AAC). The simulation results for the proposed sensing technologies are presented for various incumbent signals.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.113-121
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• 1999

It is necessary to calibrate measurement systems to enhance its measurement accuracy. The visual sensing system that is presented in our previous work has to be calibrated, too. It is a multiple mirror system for three-dimensional measurement, which is composed of a camera and a series of mirrors. It is important to calibrate the positions and orientations of the mirrors relative to the camera because they have direct influence on the relationship between the image plane and the task space. This paper presents the calibration method for the visual sensing system. To confirm the measurement performance of the implemented system. its measurement accuracy in measuring the locations in three-dimensional space is investigated. A series of experiments for measuring the locations of the circle-shaped marks are performed. Experimental results show that the sensing system can be effectively used for three-dimensional measurement.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.103-107
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• 2007

In this paper, the light screen sensing system is introduced and testified to detect small grains such as seeds or electronic chips of uneven sized. Two modules composed of transmitter-receiver sensor array and microprocessor-based sensor signal processing system are developed to realize the proposed system. Experimental results showed that the sensing signal was relatively clear and its counting performance was very stable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.538-549
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• 2008

Recently IEEE 802.22 WG has considered Cognitive Radio (CR) technology to overcome shortage of communication channels. For using CR technology, accurate and rapid sensing method selection is extremely important. According to the channel sensing method, it is of the utmost importance because it can affect the incumbent system protection. So, optimum selection of channel sensing method is very important. IEEE 802.22 gives the solution, name of fine sensing, but the solution can not adapt to various networks. So in this paper we propose Policy-based Channel Sensing Architecture and Algorithms for Cognitive Radio Networks. The proposed channel sensing architecture and algorithms can reduce both primary system detection time and quiet time in our simulation. Among the proposed sensing algorithm, channel division round robin sensing reduce average detection time up to 70% compare to fine sensing method in IEEE 802.22.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.48-52
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• 2010

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1275-1277
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• 2003

This paper presents a geological remote sensing information extraction system, the aim of which is to provide practical models and powerful tools to extract geological information from remote sensing images for geological exploration applications. After reviewing and analyzing the existing methods for geological information extraction, we developed more than ten models to enhance and extract geological information, such as alteration information, linear features and special lithological characters. The system is developed based on Erdas Imagine using its programming language. It has been successfully used in the 'reat Investigation of Land and Natural Resources of China' program.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.189-192
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• 2005

Desertification is one of the main global environmental phenomena. It has resulted in deterioration environment and poor economy, and imposed threat to the surviving environment of the overall mankind. Therefore, creating of methods for monitoring and estimate of risk desertification are necessary. Early warning system is one of important ways for monitoring and forecasting of desertification. Remote Sensing and GIS technology are as suitable tools and methods for early warning system. In this aim, we have evaluated of applications of remote sensing and GIS in monitoring and estimating desertification process (case study in Fars Province of Iran). In this research, we have considered erosion and vegetation cover parameters as main factors affecting in desertification process. The result shows that remote sensing and GIS technology could be useful in evaluation of desertification as one method for desertification early warning. Also, Results suggested that erosion and plant cover are affecting in develop the desertification process in study area.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1442-1444
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• 2003

This paper presents a geological remote sensing information extraction system, the aim of which is to provide practical models and powerful tools to extract geological information from remote sensing images for geological exploration applications. After reviewing and analyzing the existing methods for geological information extraction, we developed more than ten models to enhance and extract geological information, such as alteration information, linear features and special lithological characters. The system is developed based on Erdas Imagine using its programming language. It has been successfully used in the ‘Great Investigation of Land and Natural Resources of China’ program.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.287-304
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• 2012

Spectrum sensing is an important functionality for cognitive users to look for spectrum holes before taking transmission in dynamic spectrum access model. Unlike previous works that assume perfect knowledge of the SNR of the signal received from the primary user, in this paper we consider a realistic case where the SNR of the primary user's signal is unknown to both fusion center and cognitive radio terminals. A Kalman filter based adaptive Takagi and Sugeno's fuzzy system is designed to make the global spectrum sensing decision based on the observed energies from cognitive users. With the capacity of adapting system parameters, the fusion center can make a global sensing decision reliably without any requirement of channel state information, prior knowledge and prior probabilities of the primary user's signal. Numerical results prove that the sensing performance of the proposed scheme outperforms the performance of the equal gain combination based scheme, and matches the performance of the optimal soft combination scheme.

• Journal of Sensor Science and Technology
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• v.12 no.1
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• pp.24-33
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• 2003

This research is about a comfort sensing system for human environmental monitoring using a one-bodied humidity and temperature sensor and an air flow sensor. The thermal comfort that a human being feels in indoor environment has been known to be influenced mostly by six parameters, i.e. air temperature, radiation, air flow, humidity, activity level and clothing thermal resistance. Considering an environmental monitoring, we have designed and fabricated a one-bodied humidity and temperature sensor and an air flow sensor that detect air relative humidity, temperature and air flow in human environment using surface micromachining technologies. Micro-controller calculates a PMV (predicted mean vote) and CSV (comfort sensing vote) with sensing signals and display a PMV on LCD (liquid crystal display) for human comfort on indoor climate. Our work has demonstrated that a comfort sensing system can provide an effective means of measuring and monitoring the indoor comfort sensing index of a human being. Experimental results with simulated environment clearly suggest that our comfort sensing system can be used in many applications such as air conditioning system, feedback controlling in automobile, home and hospital etc..