As a crucial component in Cognitive Radio(CR) networks, spectrum sensing has been attracting lots of attention. Some conventional methods for spectrum sensing are sensitive to uncertain signal and noise, its applicabi...As a crucial component in Cognitive Radio(CR) networks, spectrum sensing has been attracting lots of attention. Some conventional methods for spectrum sensing are sensitive to uncertain signal and noise, its applicability is limited thereof. In this paper, a novel blind spectrum sensing method is proposed, where low-rank and sparse matrix decomposition is applied to the observation signal of a CR in the frequency domain. Then the ratio of the energy of the sparse part and the received signal in the time domain is considered as the criterion to decide whether the radio frequency band is idle by means of a comparison with a predefined threshold. The proposed method is independent of prior knowledge of signal and white noise, and has a better detection performance. Simulation experiments verify the performance of the proposed method in additive white Gaussian noise(AWGN), Rayleighand Rician channels.展开更多
The long-term memory for musical keys of familiar melodies was investigated. An experiment was conducted focusing on memory strength, music familiarity, and key transposition using musical pieces. Participants were ei...The long-term memory for musical keys of familiar melodies was investigated. An experiment was conducted focusing on memory strength, music familiarity, and key transposition using musical pieces. Participants were eighty-one Japanese undergraduate and graduate students. Eight were absolute pitch （AP） possessors and seventy-three were non-AP possessors. Two pieces of well-known classical music were selected as stimuli. These pieces were played in seven different keys： One was an original key and the other six were transposed keys in which the linear distance and harmonic distance were varied. Participants rated their strength of long-term memory for a particular segment of well-known music by comparing it with their memory of this piece. Importantly they were not required to identify the musical key of the melody. Results indicated that the strength of memory for these musical segments depended mainly on the pitch range associated with the transposed piece and partially on its key. We discussed participants＇ memory of melodies in the light of linear distance between original and transposed keys, harmonic distance between these factors, and the possibility of absolute tonality.展开更多
基金supported by the open project fund (No. 201600017) of the National Key Laboratory of Electromagnetic EnvironmentNSFC (No.61471066), China
文摘As a crucial component in Cognitive Radio(CR) networks, spectrum sensing has been attracting lots of attention. Some conventional methods for spectrum sensing are sensitive to uncertain signal and noise, its applicability is limited thereof. In this paper, a novel blind spectrum sensing method is proposed, where low-rank and sparse matrix decomposition is applied to the observation signal of a CR in the frequency domain. Then the ratio of the energy of the sparse part and the received signal in the time domain is considered as the criterion to decide whether the radio frequency band is idle by means of a comparison with a predefined threshold. The proposed method is independent of prior knowledge of signal and white noise, and has a better detection performance. Simulation experiments verify the performance of the proposed method in additive white Gaussian noise(AWGN), Rayleighand Rician channels.
文摘The long-term memory for musical keys of familiar melodies was investigated. An experiment was conducted focusing on memory strength, music familiarity, and key transposition using musical pieces. Participants were eighty-one Japanese undergraduate and graduate students. Eight were absolute pitch （AP） possessors and seventy-three were non-AP possessors. Two pieces of well-known classical music were selected as stimuli. These pieces were played in seven different keys： One was an original key and the other six were transposed keys in which the linear distance and harmonic distance were varied. Participants rated their strength of long-term memory for a particular segment of well-known music by comparing it with their memory of this piece. Importantly they were not required to identify the musical key of the melody. Results indicated that the strength of memory for these musical segments depended mainly on the pitch range associated with the transposed piece and partially on its key. We discussed participants＇ memory of melodies in the light of linear distance between original and transposed keys, harmonic distance between these factors, and the possibility of absolute tonality.
