Hierarchical Scheduling of an SDF/L Graph onto Multiple Processors

Although dataflow models are known to thrive at exploiting task-level parallelism of an application, it is difficult to exploit the parallelism of data, represented well with loop structures, since these structures are not explicitly specified in existing dataflow models. SDF/L model overcomes this shortcoming by specifying the loop structures explicitly in a hierarchical fashion. We introduce a scheduling technique of an application represented by the SDF/L model onto heterogeneous processors. In the proposed method, we explore the mapping of tasks using an evolutionary meta-heuristic and schedule hierarchically in a bottom-up fashion, creating parallel loop schedules at lower levels first and then re-using them when constructing the schedule at a higher level. The efficiency of the proposed scheduling methodology is verified with benchmark examples and randomly generated SDF/L graphs.

SCHEDULING TECHNIQUE OF ROUTE VEHICLES ON DUPLICATING STRETCHES

Schedule optimization is a proven strategy to improve service quality for public transport networks. However, current research mostly optimizes schedule design using prior knowledge of users’ routings, ignoring the optimization of public transport schedules on duplicating stretches of route vehicles. This article presents a new alignment technique of time intervals between consecutive vehicles of different routes on duplicating stretches, considering existing public transport networks in attaining optimization of public transport schedule. Scheduling technique of route vehicles on duplicating stretches includes some steps: analysis of public transport network and determining a lot of duplicating stretches, calculation of the optimal time intervals among arrivals of route vehicles and alignment of these intervals among consecutive route vehicles on duplicating stretches, realization simulation model of urban passenger transport within the simulation modeling system of GPSS World. Furthermore, testing the optimization technique of route vehicle scheduling, analysis of the quality of adjusted schedule with route vehicles of different kinds included, and determining the optimization efficiency for duplicating stretches. The adjusting technique of urban passenger transport schedule allows to increase movement steadiness of consecutive vehicles of different routes on duplicating stretches, adjust traffic intervals for each route, shorten the traffic load on stations, reducing idle time and queue lengths of route vehicles in front of transport stops and also minimize waiting time for route vehicle by those passengers who can be transported along several routes. Improving the bus schedule on duplicating stretches in Gomel is illustrated demonstrating the technique developed. This scheduling technique can be used by carriers and transport operators to improve the quality of services provided.

Collision Avoidance and Dynamic Sleep Scheduling Technique for Cluster Based Underwater Wireless Sensor Networks (UWSN)

In UWSN, during clustering, there may be occurrence of intra cluster collision. In order to overcome this issue, in this paper, we propose to design protocol to efficiently handle the intra-cluster collisions and to design sleep-wake up scheduling scheme for the data aggregation. In this case, the cluster head coordinates with its cluster members to transmit (append) their data packets with partially overlapping transmission times. After the CH finishes transmitting its packets to the courier nodes, it starts to receive incoming appended packets from its members. It then sends the packet to its parent CH towards the sink applying data fusion and sending the aggregated packet in TDMA period based on the receiver oriented sleep scheduling scheme. By simulation results, we show that the proposed technique minimizes collision and transmission delay.