Since there are cases that chickens infected with highly pathogenic avian influenza (HPAI) viruses die with almost no fever, body-temperature sensing cannot be effective for the early detection of avian influenza (AI)...Since there are cases that chickens infected with highly pathogenic avian influenza (HPAI) viruses die with almost no fever, body-temperature sensing cannot be effective for the early detection of avian influenza (AI) infection in these cases. In addition, sensors directly attached to the body surface are easily affected by their surroundings, therefore it is not easy to measure the body-temperature of chickens. This paper proposes a new method to detect abnormal states of chickens with only their activity data obtained by wearable wireless sensor nodes. The method is that if its state that the present average activity of a chicken in one hour is smaller than 0.6 times minimum average daytime activity in its life continues for 3 hours, a judgment that the chicken is abnormal state is made. This method can detect the abnormal states twice as early as that with body-temperature sensing does. Since the activity sensor nodes are easily attached to chickens and hardly affected by their surroundings, this system can be reliable.展开更多
Since power of a wireless sensor node is limited, low power communication technology has been required. M-ary frequency shift keying (MFSK) modulation with orthogonal signals is one of the methods to decrease the powe...Since power of a wireless sensor node is limited, low power communication technology has been required. M-ary frequency shift keying (MFSK) modulation with orthogonal signals is one of the methods to decrease the power. However, if the amount of transmitted data including such as an identification number (ID) of a node and measured data is small, a ratio of the data length to the total packet length, which means transmission efficiency, becomes quite low. Because a preamble and error check codes are generally added to a packet for synchronization between a transmitter and a receiver and for decrease in reception errors, respectively. In this research, we have developed a method with digital filters which eliminates the other signals from time series frequency spectra not to use a preamble and error check codes. Although estimated synchronization loss of the method was less than 1.6 dB, it was found that the loss of the method on error packet rate was almost 0 dB at more than 0.001 of packet error rate by a simulation made by BASIC. These results indicate a possibility to realize that a packet which consists of only two symbols can be received with no error if the transmitted data is less than 14 bits using 128-FSK.展开更多
We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends ...We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.展开更多
文摘Since there are cases that chickens infected with highly pathogenic avian influenza (HPAI) viruses die with almost no fever, body-temperature sensing cannot be effective for the early detection of avian influenza (AI) infection in these cases. In addition, sensors directly attached to the body surface are easily affected by their surroundings, therefore it is not easy to measure the body-temperature of chickens. This paper proposes a new method to detect abnormal states of chickens with only their activity data obtained by wearable wireless sensor nodes. The method is that if its state that the present average activity of a chicken in one hour is smaller than 0.6 times minimum average daytime activity in its life continues for 3 hours, a judgment that the chicken is abnormal state is made. This method can detect the abnormal states twice as early as that with body-temperature sensing does. Since the activity sensor nodes are easily attached to chickens and hardly affected by their surroundings, this system can be reliable.
文摘Since power of a wireless sensor node is limited, low power communication technology has been required. M-ary frequency shift keying (MFSK) modulation with orthogonal signals is one of the methods to decrease the power. However, if the amount of transmitted data including such as an identification number (ID) of a node and measured data is small, a ratio of the data length to the total packet length, which means transmission efficiency, becomes quite low. Because a preamble and error check codes are generally added to a packet for synchronization between a transmitter and a receiver and for decrease in reception errors, respectively. In this research, we have developed a method with digital filters which eliminates the other signals from time series frequency spectra not to use a preamble and error check codes. Although estimated synchronization loss of the method was less than 1.6 dB, it was found that the loss of the method on error packet rate was almost 0 dB at more than 0.001 of packet error rate by a simulation made by BASIC. These results indicate a possibility to realize that a packet which consists of only two symbols can be received with no error if the transmitted data is less than 14 bits using 128-FSK.
文摘We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.
