Faced with the limitations of the Aloha random access scheme and spread spectrum techniques, LoRaWAN is yet to realize its potential as the flagship technology for largescale Internet of Things applications. LoRaWAN allows for low power and long range communications. Nonetheless, concurrent transmissions on the same spreading factors, increased with the inevitable densification of device deployment, will lead to collisions and degradation in performance. The problem is further amplified due to the shortage in radio resources, with multiple operators utilizing the same unlicensed frequency bands. In this paper, we investigate different inter-operator cooperation schemes and devise multiple algorithms for spreading factor assignment in a multi-operator LoRaWAN deployment scenario. We start by proposing a proportional fair optimal formulation for the assignment with the objective of maximizing the logarithmic sum of the normalized throughput per spreading factor. Under the assumption of partial operator cooperation, we propose a gradient ascent based iterative algorithm for solving the spreading factor assignment problem, and a game theory based approach, wherein each network operator seeks to maximize its own normalized throughput. Finally, and with cooperation between different operators bound to be limited, we use recurrent neural networks to enable the prediction of the success rate per spreading factor. This prediction allows the different operators to assign spreading factors with minimum cooperation. We simulate our proposals and compare them to the legacy LoRaWAN approach as well as others in the state-of-the-art, highlighting the gains they produce in terms of total normalized throughput and packet delivery ratios.

Patient: Female, 66Final Diagnosis: Extraovarian primary peritoneal carcinomatosisSymptoms: Abdominal distension with constipation of 3 days, while still passing flatus. She further complained of mild postprandial epigastric pain, but denied nausea or vomiting as well as feverMedication: —Clinical Procedure: —Specialty: SurgeryObjective:Rare diseaseBackground:Extraovarian primary peritoneal carcinoma (EOPPC) is a rare malignant epithelial tumor with an age-adjusted incidence rate of 6.78 per million, which arises from the peritoneal lining with minimal or no ovarian involvement. EOPPC is a diagnosis of exclusion with the absence of other identifiable primary sites and after surgical assessment and consideration of the histological report to evaluate the extent of ovarian invasion.Case Report:A 66-year-old woman complained of mild postprandial epigastric pain. Physical exam revealed positive bowel sounds over all 4 quadrants, with a soft, non-tender abdomen. Distension and dullness to percussion were noted. A CT scan revealed peritoneal fluid, and evaluation of the peritoneal fluid showed an elevated white blood cell count, while fulfilling criteria for exudate. There was no bacterial growth from the peritoneal fluid. Serum tumor markers CEA were significantly elevated, suggestive of an underlying malignancy. An exploratory laparoscopy confirmed diffuse carcinomatosis in the omentum, the coloparietal region bilaterally, as well as surrounding small bowel loops, the transverse and sigmoid colon, and the rectum. A bilateral oophorectomy was performed and 2 biopsies from the thickened peritoneum were taken. The histomorphological features from the pathology examination concluded the patient had peritoneal serous carcinoma with uninvolved ovaries.Conclusions:EOPPC may be misdiagnosed as epithelial ovarian cancer, and should be considered in patients with peritoneal carcinomatosis, normal-sized ovaries, and no identifiable primary lesion. Since the common therapeutic strategies achieve comparable survival rates, failed recognition may be without consequences. However, to further improve survival, optimal cytoreductive surgery is essential and should be made a priority in disease management.

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