Convergecast with Unbounded Number of Channels

We consider a problem of minimum length scheduling for the conflict-free aggregation convergecast in wireless networks in a case when each element of a network uses its own frequency channel. This problem is equivalent to the well-known NP-hard problem of telephone broadcasting since only the conflicts between the children of the same parent are taken into account. We propose a new integer programming formulation and compare it with the known one by running the CPLEX software package. Based on the results of a numerical experiment, we concluded that our formulation is more preferable in practice to solve the considered problem by CPLEX than the known one. We also propose a novel heuristic algorithm, which is based on a genetic algorithm and a local search metaheuristic. The simulation results demonstrate the high quality of the proposed algorithm compared to the best known approaches

Ecology of Place

25 page PDF and alternative eBook version.Ecology of Place is concerned with the values of conservation and preservation people place on their relationship to the earth, its features and its inhabitants. By knowing a place and naming its constituents we discover our responsibilities and the meanings of its interdependencies. We may undergo the transformation from outside observer to aware partner, and our informed critical discussions can impact the evolution of society. Place itself rests in particularity and uniqueness. As we come to know and understand a particular place, it often becomes so intertwined with our life story, and the life stories of everything that lives there, that we can’t separate ourselves from the place. A place then becomes part of our voice as we incorporate its story into our lives. The Ecology of Place collection of readings for composition students contains three units designed to support the University of Oregon Composition Program’s student learning outcomes. For the most up to data, readable, and interactive version of this text visit https://openoregon.pressbooks.pub/ecologyofplace/ (see clickable link above).Open Orego

Energy-efficient Area Coverage by Sensors with Adjustable Ranges

In wireless sensor networks, density control is an important technique for prolonging a network’s lifetime. To reduce the overall energy consumption, it is desirable to minimize the overlapping sensing area of the sensor nodes. In this paper, we study the problem of energy-efficient area coverage by the regular placement of sensors with adjustable sensing and communication ranges. We suggest a more accurate method to estimate efficiency than those currently used for coverage by sensors with adjustable ranges, and propose new density control models that considerably improve coverage using sensors with two sensing ranges. Calculations and extensive simulation show that the new models outperform existing ones in terms of various performance metrics

Driving machine shaft angular velocity impact on motion conditional change of granular medium in working reservoir for components compounding and process

The granular operating medium moving in mixing and tumbling working reservoir can be implemented by cascade, waterfall and mixed motion mode of granular medium. Each granular medium motion mode corresponds to certain components process type of different branches of industry or substances mixing. The establishment of relationship between driving machine shaft angular velocity and granular operating medium motion mode is relevant objective for different branches of industry where this equipment is used. On the basis of 3D modeling and kinematic analysis, some kinematic machine parameters are determined in CAD SolsdWorks, the relationship between driving machine shaft angular velocity and granular operating medium motion mode was established analytically for proportionally modified working reservoir geometrics

Critical-Path Aware Scheduling for Latency Efficient Broadcast in Duty-Cycled Wireless Sensor Networks

Minimum latency scheduling has arisen as one of the most crucial problems for broadcasting in duty-cycled Wireless Sensor Networks (WSNs). Typical solutions for the broadcast scheduling iteratively search for nodes able to transmit a message simultaneously. Other nodes are prevented from transmissions to ensure that there is no collision in a network. Such collision-preventions result in extra delays for a broadcast and may increase overall latency if the delays occur along critical paths of the network. To facilitate the broadcast latency minimization, we propose a novel approach, critical-path aware scheduling (CAS), which schedules transmissions with a preference of nodes in critical paths of a duty-cycled WSN. This paper presents two schemes employing CAS which produce collision-free and collision-tolerant broadcast schedules, respectively. The collision-free CAS scheme guarantees an approximation ratio of in terms of latency, where denotes the maximum node degree in a network. By allowing collision at noncritical nodes, the collision-tolerant CAS scheme reduces up to 10.2 percent broadcast latency compared with the collision-free ones while requiring additional transmissions for the noncritical nodes experiencing collisions. Simulation results show that broadcast latencies of the two proposed schemes are significantly shorter than those of the existing methods