RFID Based Non-Preemptive Random Sleep Scheduling in WSN

In Wireless Sensor Network(WSN),because battery and energy supply are constraints,sleep scheduling is always needed to save energy while maintaining connectivity for packet delivery.Traditional schemes have to ensure high duty cycling to ensure enough percentage of active nodes and then derogate the energy efficiency.This paper proposes an RFID based non-preemptive random sleep scheduling scheme with stable low duty cycle.It employs delay tolerant network routing protocol to tackle the frequent disconnections.A low-power RFID based non-preemptive wakeup signal is used to confirm the availability of next-hop before sending packet.It eliminates energy consumption of repeated retransmission of the delayed packets.Moreover,the received wakeup signal is postponed to take effect until the sleep period is finished,and the waken node then responds to the sending node to start the packet delivery.The scheme can keep stable duty cycle and then ensure energy saving effect compared with other sleeping scheduling methods.

Partial Anomalous Pulmonary Venous Connection and the Nature of Associated Sinus Venosus Defect

Background:Partial anomalous pulmonary venous connection(PAPVC)is frequently associated with atrial septal defect(ASD),especially sinus venosus defect(SVD).Although Waggstaffe described the pathology of SVDs in 1868,the exact anatomic features and the nature of SVD remains controversial.SVDs with no posterior atrial rim were observed in recent years.However,no studies suggested that absence of the residual posterior atrial septal tissue might be the key feature of SVD.The aims of this study were to investigate if absence of posterior rim of atrial septum played a crucial role in patients with SVD.Methods:From January 2011 to December 2019,256 children with PAPVC combined ASD and 878 children with isolated ASD who underwent corrective cardiac surgery were consecutively enrolled.Comprehensive review of preoperative transthoracic echocardiography,computed-tomography images and surgical findings were performed by experienced pediatric cardiologists.The subtypes of PAPVC,locations and types of ASD,and presence of posterior atrial rim of associated ASD were investigated.Results:PAPVC was right-sided in 244 children,left-sided in 6 children,and bilateral in 6 children.In PAPVC cases,ASD without posterior atrial rim existed in 226 SVD cases.ASD without posterior atrial septum only existed in cases with one or more right pulmonary veins returning to right atrium(RA)or to RA-superior vena cava junction.In cases with isolated ASD,there were 3 SVD,and the other 875 cases were secundum ASD.Conclusions:ASD without posterior atrial rims was associated with one or more right pulmonary veins returning to RA or RA-superior venous cava(SVC)junction.For SVD,the key feature is that the defect is in the posterior of the interatrial septum with no posterior septal rim,rather than adjacent to the SVC or to the inferior vena cava.

Hybrid beamforming with discrete phase shifters for millimeter wave backhaul networks

Hybrid beamforming（ HBF） technology becomes one of the key technologies in the millimeter wave（ mm Wave）mobile backhaul systems,for its lower complexity and low power consumption compared to full digital beamforming（ DBF）. Two structures of HBF exist in the mm Wave mobile backhaul system,namely,the fully connected structures（ FCS） and partially connected structures（ PCS）. However,the existing methods cannot be applied to both structures. Moreover,the ideal phase shifter is considered in some current HBF methods,which is not realistic. In this paper,a HBF algorithm for both structures based on the discrete phase shifters is proposed in the mm Wave mobile backhaul systems. By using the principle of alternating minimization,the optimization problem of HBF is decomposed into a DBF optimization problem and an analog beamforming（ ABF） optimization problem.Then the least square（ LS） method is enabled to solve the optimization model of DBF. In addition,the achievable data rate for both structures with closed-form expression which can be used to convert the optimization model into a single-stream beamforming optimization model with per antenna power constraint is derived. Therefore,the ABF is easily solved. Simulation results show that the performance of the proposed HBF method can approach the full DBF by using a lower resolution phase shifter.