Due to the higher reliability and small ground space requirement, compressed GIS （gas insulated substation） has found extensive applications in urban areas and developing countries. The major parts of GIS is the gas...Due to the higher reliability and small ground space requirement, compressed GIS （gas insulated substation） has found extensive applications in urban areas and developing countries. The major parts of GIS is the gas insulated busducts, circuit breakers, isolators, etc.. The voltage withstand capability of SF6 （sulphur hexafluoride） busduct is strongly dependent on field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants which arise due to manufacturing process, mechanical vibrations, moving parts of system etc.. Contamination can create insulation problems at operating fields. An optimized design of GIS by varying the inner and outer diameter to 89 mm and 241 mm is considered for analysis and compared with a single phase enclosure with outer diameter as 152 mm and inner conductor diameter of 55 mm with aluminum and copper particles of size 10 mm in length and 0.25 mm in radius present on the enclosure. The results have been compared on the extent of particle movement for the same condition of the gas and particle geometry. Monte Carlo simulation is also carried out for determining the motion of particles in axial and radial directions. The random solid angle is changed from 1 to 0.5 degrees to take into account more smooth end profile of the particle. The simulation results have been presented and analyzed.展开更多
Neighbor discovery is important for docking applications,where mobile nodes communicate with static nodes situated at various rendezvous points.Among the existing neighbor discovery protocols,the probabilistic methods...Neighbor discovery is important for docking applications,where mobile nodes communicate with static nodes situated at various rendezvous points.Among the existing neighbor discovery protocols,the probabilistic methods perform well in average cases but they have aperiodic,unpredictable,and unbounded discovery latency.Yet,deterministic protocols can provide bounded worst-case discovery latency by sacrificing the average-case performance.In this study,we propose a mobility-assisted slot index synchronization(MASS),which is a new synchronization technique that can improve the average-case performance of deterministic neighbor discovery protocols via slot index synchronization without incurring additional energy consumption.Furthermore,we propose an optimized beacon strategy in MASS to mitigate beaconing collisions,which can lead to discovery failures in situations where multiple neighbors are in the vicinity.We evaluate MASS with theoretical analysis and simulations using real traces from a tourist tracking system deployed at the Mogao Grottoes,which is a famous cultural heritage site in China.We show that MASS can reduce the average discovery latency of state-of-the-art deterministic neighbor discovery protocols by up to two orders of magnitude.展开更多
文摘Due to the higher reliability and small ground space requirement, compressed GIS （gas insulated substation） has found extensive applications in urban areas and developing countries. The major parts of GIS is the gas insulated busducts, circuit breakers, isolators, etc.. The voltage withstand capability of SF6 （sulphur hexafluoride） busduct is strongly dependent on field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants which arise due to manufacturing process, mechanical vibrations, moving parts of system etc.. Contamination can create insulation problems at operating fields. An optimized design of GIS by varying the inner and outer diameter to 89 mm and 241 mm is considered for analysis and compared with a single phase enclosure with outer diameter as 152 mm and inner conductor diameter of 55 mm with aluminum and copper particles of size 10 mm in length and 0.25 mm in radius present on the enclosure. The results have been compared on the extent of particle movement for the same condition of the gas and particle geometry. Monte Carlo simulation is also carried out for determining the motion of particles in axial and radial directions. The random solid angle is changed from 1 to 0.5 degrees to take into account more smooth end profile of the particle. The simulation results have been presented and analyzed.
基金Project supported by the National High-Tech R&D Program of China(No.2012AA101701)the National Key Technology Support Program of China(Nos.2013BAK01B00 and2014BAK16B00)Grotto Temples Digital Protection of Cultural Relics and Equipment Upgrading of National Cultural Heritage Administration Scientific Research Institutes
文摘Neighbor discovery is important for docking applications,where mobile nodes communicate with static nodes situated at various rendezvous points.Among the existing neighbor discovery protocols,the probabilistic methods perform well in average cases but they have aperiodic,unpredictable,and unbounded discovery latency.Yet,deterministic protocols can provide bounded worst-case discovery latency by sacrificing the average-case performance.In this study,we propose a mobility-assisted slot index synchronization(MASS),which is a new synchronization technique that can improve the average-case performance of deterministic neighbor discovery protocols via slot index synchronization without incurring additional energy consumption.Furthermore,we propose an optimized beacon strategy in MASS to mitigate beaconing collisions,which can lead to discovery failures in situations where multiple neighbors are in the vicinity.We evaluate MASS with theoretical analysis and simulations using real traces from a tourist tracking system deployed at the Mogao Grottoes,which is a famous cultural heritage site in China.We show that MASS can reduce the average discovery latency of state-of-the-art deterministic neighbor discovery protocols by up to two orders of magnitude.
