7 research outputs found
Investigating ultraharmonic modeling from ultrasound echo signal with SISO volterra filter
No full textEfficient MISO 3rd-order Volterra series for modeling subharmonic oscillation of ultrasound contrast agent
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Performance analysis of linear bandpass filter and pulse inversion in separating subharmonic frequency of signals from ultrasound contrast agent
No full textRecently, many publications reported the generation of subharmonic frequency (f0/2) and its potential use in imagingfrom ultrasound contrast agent (UCA). Subharmonic imaging (SHI) has provided better contrast resolution over the secondharmonic signals due to the lack of subharmonic generation in the tissue region. However, subharmonic separation in SHIutilizes linear bandpass filtering only. In this paper, we compare the subharmonic separation capability of linear band filter(LBF), pulse inversion (PI), and their combination (PILBF) based on contrast-to-tissue ratio (CTR). Results show that theCTR values from the LBF, the PI, and the PILBF are 20.30, 40.30, and 52.74 dB, respectively. The optimal stopband attenuation and fractional bandwidth for the PILBF method are 50 dB and 10%, respectively. This high CTR value indicates thefeasibility of the PILBF method in creating high quality ultrasound image from subharmonic frequency
Measurement of LoRa-based Received Signal Strength Indication (RSSI) Using Point-to-Point Topology in a Seaside Area
No full textA data monitoring system’s performance analysis is fundamental to proving quality and networking efficiency. This paper presents the received signal strength indication (RSSI) measurements of wireless communication with point-to-point LoRa technology for use in the 433 MHz frequency band. The test was performed in the area of Chalathat beach, Songkhla province, Thailand, which has a barrier environment of trees along the shore and is opposite the Rajamangala University of Technology Srivijaya (RUTS). This demonstration was conducted in the actual location to observe the loss from coastal environment conditions from waves and sea breeze. In addition, the study aimed to determine the effect of signal performance by RSSI measurements. The test consisted of a transmitter (Tx) and a receiver (Rx) with a transmit power of 17 dBm and an antenna gain of 3 dBi on both Tx and Rx. The testing starts with RSSI measurements from a distance of 10 meters and increases the number of measures by 10 meters until data loss begins. The test results showed that communication distances could be connected up to 500 meters without packet loss, with RSSI as low as -107 dBm, and a correlation graph in the form of a logarithmic function with a reduced tendency. However, the RSSI value decreases as the distance increases. At the same time, the test results can indicate its effectiveness as a guide for further application of monitoring systems at the beach area
Battery Lifetime Analysis of XBee Sensor Using Transmission Power and Period Approaches: A Case of Server Room Monitoring System
No full textIn the server room, it is necessary to monitor the appropriate temperature for the efficient use of electricity. Especially in hot regions and seasons. For example, April is the summer in Thailand where the temperature is about 35-40 OC every year, but the optimum temperature for the server room is about 20-22 OC. This paper presents the measurement of a wireless temperature system through the use of XBee sensors to monitor the real-time server room temperature. The system consists of an XBee sensor node, Gateway (GW), and IoT cloud server. In addition, the measuring device can use a wireless sensor, it is convenient and easy to install as well.Therefore, when choosing a wireless sensor device, it is necessary to test its performance in terms of both the period and the power transmission of the device. Such parameters affect the battery lifetime. The results of the measurement of the sensor’s energy efficiency measured the voltage drop of the device by adjusting the power transmitter and period of the XBee sensors. These parameters directly affect the battery power output and are expected to benefit users in the future
