• ETRI Journal
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• v.41 no.2
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• pp.176-183
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• 2019

Spectrum sensing plays an important role in spectrum sharing. Energy detection is generally used because it does not require a priori knowledge of primary user (PU) signals; however, it is sensitive to noise uncertainty. An order statistics (OS) detector provides inherent protection against nonhomogeneous background signals. However, no analysis has been conducted yet to apply OS detection to spectrum sensing in a wireless channel to solve noise uncertainty. In this paper, we propose a robust spectrum sensing scheme based on generalized order statistics (GOS) and analyze the exact false alarm and detection probabilities under noise uncertainty. From the equation of the exact false alarm probability, the threshold value is calculated to maintain a constant false alarm rate. The detection probability is obtained from the calculated threshold under noise uncertainty. As a fusion rule for cooperative spectrum sensing, we adopt an OR rule, that is, a 1-out-of-N rule, and we call the proposed scheme GOS-OR. The analytical results show that the GOS-OR scheme can achieve optimum performance and maintain the desired false alarm rates if the coefficients of the GOS-OR detector can be correctly selected.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.635-640
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• 2009

After 1960s, in accordance with getting bigger in changing range of annual rain precipitation, those dams were built in order to prevent any drought and flood through the regulation of flux. In case of such dam, when it reaches to some definite pondage, for its regulation of water volume, numerous volume of water in the reservoir should be discharged by opening the floodgate, at this time a severe damage can be occurred to those lives and properties of the residents and tourists at the river or riverside. Accordingly, despite the sounding alarm broadcasting for prevention and notice such damage could be clearly travelled to those people without influence by the discharging noise or other neighboring environmental factor, since it was only empirically installed without any peculiar research until now, the alarm broadcasting could not effectively travel, and the travelling distance also could not known correctly. On such point of view, this Study has ever grasped the characteristics by frequencies and its sound pressure level about the discharge noise and the alarm broadcasting of Daechung Dam, one of multipurpose dams through the measurement and analysis by distances, and based on this, also has ever presupposed the proper location of additional alarm broadcasting spot using a simulation program named Cadna-A.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.40-44
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• 2015

Most people do not think seriously about the concept of time management, just to spend the precious time sheets. Regular life can sustain mental and physical health. That's why time management is an important factor in living. In the thesis, smart alarm patch is designed using a wireless communication NFC technology that gradually develop and attract attention. Due to the alarm, regular hours is helped to improve the quality of life. For this, analysis was performed using the UML in this system, linked to the smart alarm system patches and NFC technology, Java Script language, Adobe Muse CC was used embody web document and mobile content.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1162-1168
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• 2007

In many fire emergencies, the audible fire alarm signals are very important to save the occupant's life. But as the sound insulation of building elements has been improved, it is more difficult for occupant to recognize the fire alarm signals when the fire alarm worked. This is the study to show the sound attenuation of the fire alarm sounder system in apartment buildings. We measured and analyzed the sound attenuation level in 17 units, and the results were compared with the minimum sound level at sleeping area by NFPA(National Fire Protection Association) 72. When only the fire alarm worked in stair hall, the sound levels in bedroom were in the range of $30.6{\sim}42.8dB(A)$ and the differences between sound level and ambient sound level in bedrooms were in the range of $7.1{\sim}13.8dB(A)$. And when the emergency broadcasting device in the livingroom and the fire alarm worked simultaneously, the sound levels in bedrooms were in the range of $54.2{\sim}63.0dBA$. Finally, it was showed that the fire alarm sounder system didn't give a sufficient sound level in bedroom to awake out of sleep.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.197-202
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• 2016

In this paper, a danger signal to tell caregivers when a dangerous situation occurs, the bio-signal analysis in infants to prevent sudden infant death sudden infant death propose a monitoring system. The Sudden infant death (SID) refers to a healthy baby is unexplained deaths between birth year in the month. Sudden infant death proposed monitoring system is composed of a processor unit and the monitoring and alarm part for processing part and the biological signal sensing biological signals. Using the PPG sensor to sense the bio-signal and the processor unit the signal obtained through the sensor by removing the motion artifact was able to alarm and monitoring the parent.The proposed system will send the alarm to monitoring and alerting caregivers if the risk situation by analyzing the heart rate of the infant. With the actual implementation of the system to evaluate the performance of the monitoring system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.141-148
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• 2012

Android that was made by Google and Open Handset Alliance is the open source software toolkit for mobile phone. Nowadays, Smart phone users have been rapidly increasing, by that reason a lot of application contents have been released and especially contents which focus on user convenience have been developed. In this paper, we develop a new application content smart alarm based on Google Android flatform. The features of the developed content are as follows. First, users set their day's schedules. So they can notify easily what they have to do at the moment. Second, when users set their alarms not to forget several sequential tasks, they can set their schedules by not only alarm method but also timer method. In the performance evaluation, we show the results of simulation using AVD(Android Virture Device).

• Journal of Broadcast Engineering
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• v.18 no.6
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• pp.823-834
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• 2013

In this paper, we propose a detection method for Digital Radio Mondiale (DRM) Plus suitable for hybrid mode broadcasting which services both DRM Plus and analog FM within the same frequency band. The guard-interval correlation method of Orthogonal Frequency Division Multiplexing (OFDM) is good for DRM Plus signal detection, but the possibility for false alarm increases when FM signal is received. The proposed method includes a reference block in the guard-interval correlation which increases the identification rate of weak DRM Plus signals and decreases the possibility of false alarm when analog FM is received. The performance of the proposed method is verified through simulations.

• International journal of advanced smart convergence
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• v.7 no.2
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• pp.112-118
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• 2018

This paper describes the design and implementation of a vehicle internal alarm system using raspberry-pie and gas sensor. It provides a notification system for sleepiness during driving, a driving time notification system and a smoking detection system. We coded using 'Python'. And we use 'MySQL' and 'PHP' to build the necessary servers and web pages for gathering sensing data and monitoring. The developed system was tested by several methods. All experiments showed satisfactory response signals and detected with immediate responses.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.21-27
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• 2022

As society develops and becomes more complex, new and diverse types of disasters such as fine dust and infectious diseases are occurring. However, in the past, there was no PA(Public Address) system that provided accurate information to prepare for such a disaster. In this paper, we propose a public address system that automatically broadcasts an alarm by analyzing polluted air quality data collected from public data and IoT sensors. The warning level varies depending on the air quality, and the information provided by public data may show a significantly different result from the guide area due to various factors such as the distance from the measuring station or the wind direction. To compensate for this, we are going to propose a method for broadcasting by comparing and analyzing data obtained from public data and data from on-site IoT sensors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.627-628
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• 2008