An oligopolistic model of an integrated market for energy and spinning reserve

In this paper, a model for oligopolistic competition in electricity markets is presented. Most previous proposed models have been static and focused only on the energy market incentives for strategic behavior. In contrast, in this paper, a multiperiod market for energy and spinning reserve (SR) is considered. By including such factors, the competition among participants is modeled with more realism. Competition in the energy market is modeled by means of conjectured supply functions, while conjectured reserve-price response functions are used to consider the generators' ability to alter the SR prices. The resulting equilibrium problem is modeled in terms of complementarity conditions. Based upon a complementarity model, the opportunity cost between the energy and SR markets is derived for oligopolistic markets. The proposed model is illustrated by a six-node network using a dc approximation.     

Reduction of electromagnetic field coupling to microwave microstrip circuits

The signals induced by an external electromagnetic field along a microstrip line on a multilayered dielectric substrate were studied. The main target of the work is not to introduce a new technique of study but to search for suitable combinations of the structural and geometrical characteristics of the printed geometry whereby the electromagnetic interference of the external field to the circuit would be reduced. This reduction is desirable in all modern applications. The results derived prove that this object can be achieved at high frequencies and when the substrate is multilayered.     

A novel frequency-offset monitoring technique for direct-detection DPSK systems

We propose and demonstrate a novel technique to monitor the frequency offset between the optical source and delay interferometer (DI) for direct-detection differential phase-shift-keying (DPSK) systems. In this scheme, a phase-modulated tone is applied to DPSK signals at the transmitter and then detected after being converted into an amplitude-modulated tone at the DI to be used for the monitoring signal. Our experimental demonstration shows that the monitoring range and sensitivity of the proposed scheme are measured to be /spl plusmn/2 GHz and /spl sim/10 MHz, respectively, which we believe are good enough to be used either to generate alarm signals for the frequency offset monitoring or to control the feedback loop of the DI.     

The Infeasible SIR Region Is Not a Convex Set

The infeasible signal-to-interference ratio (SIR) region is a set of SIRs that are not supportable in a power-controlled wireless network. It was conjectured that this set is convex in networks constrained on total power. We disprove the conjecture and discuss how this result may impact optimal medium-access control policies     

Clustering for Processing Rate Optimization

Clustering (or partitioning) is a crucial step between logic synthesis and physical design in the layout of a large scale design. A design verified at the logic synthesis level may have timing closure problems at post-layout stages due to the emergence of multiple-clock-period interconnects. Consequently, a tradeoff between clock frequency and throughput may be needed to meet the design requirements. In this paper, we find that the processing rate, defined as the product of frequency and throughput, of a sequential system is upper bounded by the reciprocal of its maximum cycle ratio, which is only dependent on the clustering. We formulate the problem of processing rate optimization as seeking an optimal clustering with the minimal maximum-cycle-ratio in a general graph, and present an iterative algorithm to solve it. Experimental results validate the efficiency of our algorithm     

Cavity-Backed Miniature Wideband UHF Circular Polarized Antenna With Textured Dielectrics

Use of high permittivity dielectrics with antennas is known to reduce their operating frequency but also introduces side effects such as reduced gain and bandwidth. This paper presents a miniaturization scheme for a 15 cm (6 inch) square circularly polarized (CP), cavity-backed antenna using textured dielectric loading and a folded metallic strip feed. The proposed design has an operational frequency f, around 500 MHz implying a linear size of 0.25lambda₀. The challenge in designing such a small size antenna is to increase bandwidth (10-15%) while retaining a gain of 2-4 dBi. By carefully positioning high permittivity textured dielectrics within the aperture in conjunction with shape design, we show that bandwidth and gain are retained as compared to comparable size antennas in the literature. As part of our design, we present parametric studies through computer simulations and a prototype antenna is fabricated and measured for verification     

Structural reliability assessment of multi-stack package (MSP) under high temperature storage (HTS) testing condition

Wire ball open failure at the interface of the gold wire and bonding pad of a multi-stack package (MSP) under high temperature storage (HTS) condition of 150 °C is studied. Failure analysis using FIB-SEM was conducted by in-plane moiré interferometry and FEA to clarify the failure mechanism. The ball open failure due to Kirkendall void that results from metal diffusion at high temperature was accelerated by the tensile stress imposed at the gold wire. The tensile stress developed at the gold wire when packages showing different warpage behaviours were stacked. Mechanical interaction between top and bottom packages caused unstable warpage, readily twisted and saddled. The wire came in contact with the photo-sensitive solder resist (PSR) dam because of the unstable warpage and this contact resulted in tensile stress at the gold wires. Solder flux residues reacted with the encapsulant, and as a result, the encapsulant of the top package adhered to the chip of the bottom package, and this adherence created additional tensile stress at the gold wires. To reduce the tensile stress at the wires, the PSR dam was removed, loop shape was altered from 45° to 90°, water soluble flux was applied, and cleaning process was added. HTS reliability was significantly improved and guaranteed after reducing the tensile stress at the wires.     

Structural and electronic properties of zirconia phases: A FP-LAPW investigations

The structural and electronic properties of ZrO₂ polymorphs were investigated using density functional theory (DFT). The Kohn–Sham equations were solved by applying the full-potential linearized augmented plane wave (FP-LAPW) method. We used the generalized gradient approximation (GGA) in the Perdew–Wang formalism to the exchange and correlation energy functional. The ground state properties such as lattice parameter, transition pressures, bulk modulus and its pressure derivative as well as the structural phase stability were calculated. The results were compared with previous calculations and experimental data when available. The FP-LAPW method correctly orders the zero temperature energies of all zirconia polymorphs. We have also studied the effect of distortion from the cubic to the tetragonal structure on the basis of charge density calculations. On the other hand, band structure and density of states (DOS), which allow us to discuss the features of orbital mixing, are also given. Our results suggest that the cotunnite structure should be better than the other zirconia phases as gate dielectric material.     

Intercomparison of Thermophysical Property Measurements on an Austenitic Stainless Steel

The results of an inter laboratory comparison of thermal conductivity, thermal diffusivity, specific heat capacity, and thermal expansion measurements on austenitic stainless steel in the temperature range between 20 and 1000°C are presented here. Mean values are presented for the physical properties studied. Reliable relative expanded uncertainties can be stated for the properties determined, which were achieved by applying good measurement practice, i.e., 3% for thermal expansion, 5% for specific heat capacity and thermal diffusivity, and 6% for thermal conductivity. The mean values derived from this intercomparison agree well with the results of a previous intercomparison in 1990. An erratum to this article is availabale at .     

Calculations of impurity doping effects in CrO/sub 2/

The effects of impurity doping in CrO/sub 2/ have been calculated based on the Cr/sub 9/O/sub 40/ cluster using the method of DV-X /spl alpha/ molecular orbital calculation. Elements (Mo, W) belonging to the same family as Cr and the ones (Zr, Ru, Sn) whose dioxides have the same crystalline structure as the rutile were selected for impurity doping. The calculated results show the large enhancements of the magnetic moment and the Curie temperature by the doping of Zr and Ru, respectively.