33,488 research outputs found
Modeling and Simulation of Regenerative Braking Energy in DC Electric Rail Systems
Regenerative braking energy is the energy produced by a train during
deceleration. When a train decelerates, the motors act as generators and
produce electricity. This energy can be fed back to the third rail and consumed
by other trains accelerating nearby. If there are no nearby trains, this energy
is dumped as heat to avoid over voltage. Regenerative braking energy can be
saved by installing energy storage systems (ESS) and reused later when it is
needed. To find a suitable design, size and placement of energy storage, a good
understanding of this energy is required. The aim of this paper is to model and
simulate regenerative braking energy. The dc electric rail transit system model
introduced in this paper includes trains, substations and rail systems
Conformal mapping of unbounded multiply connected regions onto canonical slit regions
We present a boundary integral equation method for conformal mapping of unbounded multiply connected regions onto five types of canonical slit regions. For each canonical region, three linear boundary integral equations are constructed from a boundary relationship satisfied by an analytic function on an unboundedmultiply connected region. The integral equations are uniquely solvable. The kernels involved in these integral equations are the modified Neumann kernels and the adjoint generalized Neumann kernels
Mass Rearing of the Greater Wax Moth, \u3ci\u3eGalleria Mellonella\u3c/i\u3e (Lepidoptera: Pyralidae), for Small-Scale Laboratory Studies
A technique was developed to mass rear the greater wax moth, Galleria mellonella, economically (ca. 0.2 cents per larva exclusive of 3-5 h of labor costs per week). Mortality in the egg and early larval stages was ca. 48% whereas in later larval and pupal stages it was ca. 10% and 27% respectively. With a fecundity of 650-1120 eggs per female, and notwithstanding the high egg and early larval mortality, the procedure easily provides a self-sustaining culture with high yields of all stages
Experimental investigation of feedforward control schemes of a flexible robot manipulator system
This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse
Energy Efficient Multiuser Scheduling: Statistical Guarantees on Bursty Packet Loss
In this paper, we consider energy efficient multiuser scheduling. Packet loss
tolerance of the applications is exploited to minimize average system energy.
There is a constraint on average packet drop rate and maximum number of packets
dropped successively (bursty loss). A finite buffer size is assumed. We propose
a scheme which schedules the users opportunistically according to the channel
conditions, packet loss constraints and buffer size parameters. We assume
imperfect channel state information at the transmitter side and analyze the
scheme in large user limit using stochastic optimization techniques. First, we
optimize system energy for a fixed buffer size which results in a corresponding
statistical guarantee on successive packet drop. Then, we determine the minimum
buffer size to achieve a target (improved) energy efficiency for the same (or
better) statistical guarantee. We show that buffer size can be traded
effectively to achieve system energy efficiency for target statistical
guarantees on packet loss parameters.Comment: Proc. Physcomnet in conjunction with WIOPT 201
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