ABSTRACT
This paper investigates how to efficiently charge sensor nodes in a wireless rechargeable sensor network (WRSN) with radio frequency (RF) chargers to make the network sustainable. An RF charger is assumed to be equipped with a uniform circular array (UCA) of 12 antennas with the radius λ, where λ is the RF wavelength. The UCA can steer most RF energy in a target direction to charge a specific WRSN node by the beamforming technology. Two evolutionary algorithms (EAs) using the evolution strategy (ES), namely the Evolutionary Beamforming Optimization (EBO) algorithm and the Evolutionary Beamforming Optimization Reseeding (EBO-R) algorithm, are proposed to nearly optimize the power ratio of the UCA beamforming peak side lobe (PSL) and the main lobe (ML) aimed at the given target direction. The proposed algorithms are simulated for performance evaluation and are compared with a related algorithm, called Particle Swarm Optimization Gravitational Search Algorithm-Explore (PSOGSA-Explore), to show their superiority.
ABSTRACT
Posterior retroperitoneoscopic approach (PRA) has become an established procedure for retroperitoneal lesions. The authors encountered a 30-year-old male patient who had ß-thalassemia major and received splenectomy 15 years previously. Bilateral suprarenal tumors were noted on follow-up sonography. Subsequent computed tomography of the abdomen showed a right adrenal tumor and a left intraperitoneal lesion with homogenous enhancement. Successful bilateral PRA was performed, and histology confirmed the diagnosis of right adrenal myelolipoma and an accessory spleen. For the present case who had a large abdominal scar, PRA is technically feasible for treating patients with intraperitoneal and/or retroperitoneal suprarenal lesions while eliminating the necessity of dissection for intra-abdominal adhesions and patient repositioning for bilateral lesions.
