Transmission constraints impacts on monopolistic production capacity under strategic bidding

In power systems, transmission network constraints and losses can introduce gross distortions in the market for electrical energy. Congestion occurs frequently in weakly connected networks and may split a market into regions unable to compete properly with each other. The oligopoly structure of the market and the network constraints may produce results far from the perfect competition. This may cause lack of cheap energy in some areas and surplus in others. Consideration of market power caused by congestion is the main aids of our paper. We have used a methodology in order to evaluate any events that are suspected to have any relation to the market power. Since some participants have the ability to raise prices without losing market share, we should identify them and determine the amount of this energy. Bidding strategies, such as withholding capacity and bidding at higher price, influence the network and cause transmission congestion. The methodology was tested on IEEE 30 buses standard system by some indices such as HHI and Lerner index, finally the results of identification have been confirmed. For this simulation MATPOWER version 3.2 was used as OPF solver using both AC and DC power flow representation

DOA estimation using multiple measurement vector model with sparse solutions in linear array scenarios

A novel algorithm is presented based on sparse multiple measurement vector (MMV) model for direction of arrival (DOA) estimation of far-field narrowband sources. The algorithm exploits singular value decomposition denoising to enhance the reconstruction process. The proposed multiple nature of MMV model enables the simultaneous processing of several data snapshots to obtain greater accuracy in the DOA estimation. The DOA problem is addressed in both uniform linear array (ULA) and nonuniform linear array (NLA) scenarios. Superior performance is demonstrated in terms of root mean square error and running time of the proposed method when compared with conventional compressed sensing methods such as simultaneous orthogonal matching pursuit (S-OMP), l_2,1 minimization, and root-MUISC

Compact THz waveguide filter based on periodic dielectric-gold rings

A band pass filter based on hollow circular waveguide loaded with axially periodic dielectric and gold rings is demonstrated for THz frequencies. The presence of coaxial gold rings can introduce the single mode operation due to a high rejection values at the both-sides of pass-band, and an acceptable confinement for the proposed structure. The presented numerical results show that the influences of the gold rings on the propagation properties are significant

Tunable compression of THz chirped pulses using a helical graphene ribbon-loaded hollow-core waveguide.

Pulse shaping is important for communications, spectroscopy, and other applications that require high peak power and pulsed operation, such as radar systems. Unfortunately, pulse shaping remains largely elusive for terahertz (THz) frequencies. To address this void, a comprehensive study on the dispersion tunability properties of THz chirped pulses traveling through a dielectric-lined hollow-core waveguide loaded with a helical graphene ribbon is presented. It is demonstrated that there is an optimal compression waveguide length over which THz chirped pulses reach the maximum compression. The optimal length is dependent on the chirp pulse duration. It is shown that by applying an electrostatic controlling gate voltage (Vg) of 0 and 30 V on the helical graphene ribbon, the temporal input pulses of width 8 and 12 ps, propagating through two different lengths, can be tuned by 5.9% and 8%, respectively, in the frequency range of 2.15-2.28 THz