• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.45-50
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• 2010

In this paper, we analysis the performance of cooperative spectrum sensing with distance based weight for cognitive radio (CR) systems and CR systems sense the spectrum of the licensed user by using a energy detection method. Threshold is determined in accordance with the constant false alarm rate (CFAR) algorithm for energy detection. The signal of licensed user is OFDM signal and the wireless channel between a licensed user and CR systems is modeled as Gaussian channel. From the simulation results, the cooperative spectrum sensing with distance based weight combining (DWC) and equal gain combing (EGC) methods shows higher spectrum sensing performance than single spectrum sensing does. And the detection probability performance with the DWC is higher than that with the EGC.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.81-88
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• 2018

Spectrum sensing, the key technology of the cognitive radio networks, is used by a secondary user to determine the frequency state of a primary user. The energy detection in the spectrum sensing determines the presence or absence of a primary user according to the intensity of the allocated channel signal. Since this technique simply uses the strength of the signal for spectrum sensing, it is difficult to detect the signal of a primary user in the low SNR band. In this paper, we propose a way to combine spectrum sensing and support vector machine using wavelet packet decomposition to overcome performance degradation in low SNR band. In our proposed scheme, the sensing signals were extracted by wavelet packet decomposition and then used as training data and test data for support vector machine. The simulation results of the proposed scheme are compared with the energy detection using the AUC of the ROC curve and the accuracy according to the SNR band. With simulation results, we demonstrate that the proposed scheme show better determining performance than one of energy detection in the low SNR band.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1060-1063
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• 2003

Electron spin resonance (ESR) spectroscopy was used to investigate the effects of irradiation doses and storage times on three spices. Three imported spices (Brassica juncea, Origanum vulgare, Laurus nobilis) were irradiated with doss of 0, 1, 5 and 10 kGy using a Co-60 irradiator at room temperature. ESR signals were measured from each sample by a Bruker-EPR spectrometer. The gamma-irradiated Brassica and Laurus nobilis exhibited characteristic signals, which were different from those of the non-irradiated ones. Non-irradiated and irradiated Origanum vulgare exhibited single lines, with higher ESR signals in irradiated sample than in non-irradiated sample. The ESR signals increased linearly with increasing irradiation doses $(1{\sim}10kGy)$. A strong positive correlation coefficient $(R^2=0.9939{\sim}0.9993)$ was obtained between the irradiation doses and the corresponding ESR signal intensities. Although the ESR signal intensities decreased with storage time, signals from the three irradiated spices were observed even after 12 weeks of storage at room temperature.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.423-429
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• 2011

Cooperative spectrum sensing is proposed to overcome some problem such as multipath fading and shadowing and to improve spectrum sensing performance. There are different combining methods for cooperative spectrum sensing: hard decision method and soft decision method. In this paper, we analysis the performance of cooperative spectrum sensing with distance based weight that is kind of a soft decision rule for cognitive radio(CR) systems and CR systems sense the spectrum of the licensed user by using a energy detection method. Threshold is determined in accordance with the constant false alarm rate(CFAR) algorithm for energy detection. The signal of licensed user is OFDM signal and the wireless channel between a licensed user and CR systems is modeled as Gaussian channel. From the simulation results, the cooperative spectrum sensing with distance based weight combining(DWC) and equal gain combing(EGC) methods shows higher spectrum sensing performance than single spectrum sensing does. And the detection probability performance with the DWC is higher than that with the EGC.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.72-77
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• 2011

Spectrum sensing is a critical functionality of CR network; it allow secondary user to detect spectral holes and to opportunistically use under-utilized frequency bands without causing harmful interference to primary use. Recently, wideband service has been increase for processing abundance of data traffic. So CR network needs a realizable implementation design of spectrum sensing for wideband. To get high resolution performance of wideband sensing must precede algorithm processing for reliability signal detection. By the way, the performance of spectrum sensing can be degraded due to fading and shadowing. In order to overcome this problem, we propose system model of wideband sensing scheme on energy detected collaborative technique. we divide wideband into narrowbands and use narrowbands to detect signal excepting some narrowbands including bad channel through the CSI. And we simulate and analyze in terms of detection probability with various SNR.

• Exercise Science
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• v.26 no.3
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• pp.229-237
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• 2017

PURPOSE: This study was to investigate the Glycolysis mediated sarcoplasmic reticulum (SR) $Ca^{2+}$ signal regulates mitochondria $Ca^{2+}$ during skeletal muscle contraction by using glycolysis inhibitor. METHODS: To examine the effect of Glycolysis inhibitor on SR and mitochondria $Ca^{2+}$ content, we used skeletal muscle fiber from gastrocnemius muscle. 2-deoxy glucose and 3-bromo pyruvate used as glycolysis inhibitor, it applied to electrically stimulated muscle contraction experiment. Intracellular $Ca^{2+}$ content, SR, mitochondria $Ca^{2+}$ level and mitochondria membrane potential (MMP) was detected by confocal microscope. Mitochondrial energy metabolism related enzyme, citric acid synthase activity also examined for mitochondrial function during the muscle contraction. RESULTS: Treatment of 2-DG and 3BP decreased the muscle contraction induced SR $Ca^{2+}$ increase however the mitochondria $Ca^{2+}$ level was increased by treatment of inhibitors and showed and overloading as compared with the control group. Glycolysis inhibitor and thapsigargin treatment showed a significant decrease in MPP of skeletal muscle cells compared to the control group. CS activity significantly decreased after pretreatment of glycolysis inhibitor during skeletal muscle contraction. These results suggest that regulation of mitochondrial $Ca^{2+}$ levels by glycolysis is an important factor in mitochondrial energy production during skeletal muscle contraction CONCLUSIONS: These results suggest that mitochondria $Ca^{2+}$ level can be regulated by SR $Ca^{2+}$ level and glycolytic regulation of intraocular $Ca^{2+}$ signal play pivotal role in regulation of mitochondria energy metabolism during the muscle contraction.

• Journal of Biomedical Engineering Research
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• v.8 no.2
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• pp.171-176
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• 1987

Wiener filtering method was applied to the dual energy imaging procedure in digital radiography(D.R.). A linear scanning photodiode arrays with 1024 elements(0.6mm H 1.3mm pixel size) were used to obtain chest images in 0.7 sec. For high energy image acquisition, X-ray tube was set at 140KVp, 100mA with a rare-earth phosphor screen. Low energy image was obtained with X-ray tube setting at 70KVp, 150mA. These measured dual energy images are represented in the vector matrix notation as a linear discrete model including the additive random noise. Then, the object images are restored in the minimum mean square error sense using Wiener filtering method in the transformed domain. These restored high and low energy images are used for computation of the basis image decomposition. Then the basis images are linearly combined to produce bone or tissue selective images. Using this process, we could improve the signal to noise ratio characteristics in the material selective images.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.3
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• pp.200-208
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• 2001

In indoor temperature control of a heat pump, a reduction in energy consumption is very important. However, most control schemes for heat pumps have focused only on control performance such s settling time and steady-state error. In this paper, the model predictive control (MPC) which includes the energy-related variable in this cost function is proposed. By computing the control signal minimizing this cost function, the trade-off between energy reduction and temperature control performance can be obtained. Since the MPC required the process model, the dynamic mode of a heat pump is also obtained by the system identification technique. Performance of the proposed MPC considering energy efficiency is compared with the two other control schemes. It si shown that the proposed scheme can consume less energy thant hte others in achieving similar control performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.12
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• pp.1279-1286
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• 2004

This paper continues companion paper, part I : measurement and analysis. As shown in companion Paper, information and energy in monaural signal is quite different from that of binaural signal. In this paper, difference between monaural and binaural signal of transportation noise are investigated in subjective response test. We executed hearing screening test before giving a subject response test and excluded subjects who had physical hearing loss. An annoyance response test was conducted using headphone to avoid cross-talk effect in binaural testing. Percentage of highly annoyed under binaural signal reproduction is higher than percentage of highly annoyed under monaural signal reproduction. Result implies binaural reproduction technique is proper for a study of human response to short-term noise exposure in a headphone simulated-environment.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.243-246
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• 2003

In this paper, we propose a new digital audio watermarking technique with the wavelet transform. The watermark is embedded by eliminating unnecessary information of audio signal based on human auditory system (HAS). This algorithm is an audio watermarking method, which does not require any original audio information in watermark extraction process. In this paper, the masking effect is used for audio watermarking, that is, post-tempera] masking effect. We construct the window with the synchronization signal and we extract the best frame in the window by using the zero-crossing rate (ZCR) and the energy of the audio signal. The watermark may be extracted by using the correlation of the watermark signal and the portion of the frame. Experimental results show good robustness against MPEG1-layer3 compression and other common signal processing manipulations. All the attacks are made after the D/A/D conversion.