UAV-assisted cooperative offloading energy efficiency system for mobile edge computing

Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still exist.Due to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of terminals.Considering the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy consumption.However,the resulting optimization problem is originally nonconvex and thus,difficult to solve optimally.To tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex subproblems.Furthermore,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser terminals.Simulation results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.

Hemophagocytic lymphohistiocytosis after autologous stem cell transplantation in angioimmunoblastic T-cell lymphoma:A case report

BACKGROUND Angioimmunoblastic T-cell lymphoma(AITL), a unique subtype of peripheral Tcell lymphoma, has relatively poor outcomes. High-dose chemotherapy with autologous stem cell transplantation(ASCT) can achieve complete remission and improve outcomes. Unfortunately, subsequent T-cell lymphoma-triggered hemophagocytic lymphohistiocytosis(HLH) has a worse prognosis than B-cell lymphoma-triggered HLH.CASE SUMMARY We here report a 50-year-old woman with AITL who achieved a favorable outcome after developing HLH 2 mo after receiving high-dose chemotherapy/ASCT. The patient was initially admitted to our hospital because of multiple enlarged lymph nodes. The final pathologic diagnosis, made on biopsy of a left axillary lymph node was AITL(Stage Ⅳ, Group A). Four cycles of the following chemotherapy regimen were administered: Cyclophosphamide 1.3 g, doxorubicin 86 mg, and vincristine 2 mg on day 1;prednisone 100 mg on days 1-5;and lenalidomide 25 mg on days 1-14. The interval between each cycle was 21 d. The patient received a conditioning regimen(busulfan, cyclophosphamide, and etoposide) followed by peripheral blood stem cell infusion. Unfortunately, she developed sustained fever and a low platelet count 17 d after ACST, leading to a diagnosis of HLH after ASCT. During treatment, she experienced thrombocytopenia and Pneumocystis carinii pneumonia. The patient was successfully treated with etoposide and glucocorticoids.CONCLUSION It is possible that development of HLH is related to immune reconstitution after ASCT.