Regular Variation and the Identification of Generalized Accelerated Failure-Time Models

Ridder (1990) provides an identification result for the Generalized Accelerated Failure-Time (GAFT) model. We point out that Ridder's proof of this result is incomplete, and provide an amended proof with an additional necessary and sufficient condition that requires that a function varies regularly at zero and infinity. We also give more readily interpretable sufficient conditions on the tails of the error distribution or the asymptotic behavior of the transformation of the dependent variable. The sufficient conditions are shown to encompass all previous results on the identification of the Mixed Proportional Hazards (MPH) model. Thus, this paper not only clarifies, but also unifies the literature on the non-parametric identification of the GAFT and MPH models.duration analysis;identifiability;Mixed Proportional Hazards model;regular variation

Infrared structure of e+e−→3e^+e^- \to 3 jets at NNLO: QED-type contributions

The NNLO QCD corrections to the $e^+e^- \to 3$ jets can be decomposed according to their colour factors. Out of the seven colour factors, three are of QED-type: $1/N^2$, $N_F/N$ and $N_F^2$. We use the antenna subtraction method to compute these contributions, providing complete expressions for the subtraction terms in $N_F/N$ and $N_F^2$.Comment: Talk presented at Loops and Legs 2006, Eisenac

Design of waveguides, bends and splitters in photonic crystal slabs with hexagonal holes in a triangular lattice

Waveguides in photonic crystal slabs (PCS) can be obtained by omitting a row of holes (W1-waveguides). In general the propagation properties in such waveguides suffer from the unavoidable periodic sidewall corrugation caused by the remaining parts of the crystal. The corrugation acts as a Bragg reflector, causing the occurrence of so-called mini stopbands in the transmission of the waveguide. The effect is quite strong in PCS with circular holes, but it can be significantly reduced if correctly oriented hexagonal holes are used. This so-called hexagon-type PCS allows the design of waveguides, bends and splitters having a relatively high group velocity and a wide transmission window in the PCS stopband for modes having their magnetic field oriented mainly perpendicular to the slab

Towards e+e- --> 3 jets at NNLO by sector decomposition

A method based on sector decomposition has been developed to calculate the double real radiation part of the process e+e- to 3 jets at next-to-next-to-leading order. It is shown in an example that the numerical cancellation of soft and collinear poles works well. The method is flexible to include an arbitrary measurement function in the final Monte Carlo program, such that it allows to obtain differential distributions for different kinds of observables. This is demonstrated by showing 3-, 4- and 5-jet rates at order alpha_s^3 for a subpart of the process.Comment: 14 pages, 4 figure

Passband flattening and rejection band broadening of a periodic Mach-Zehnder wavelength filter by adding a tuned ring resonator

A thermo-optically tuneable periodic wavelength filter having a rectangular wavelength response with a 50 GHz free spectral range, based on a Mach-Zehnder interferometer with ring resonator has been fabricated in SiON waveguide technology

The sector decomposition approach to real radiation at NNLO

A method based on sector decomposition is briefly described which is suitable for the calculation of the double real radiation part of e^+e^- to 3 jets at next-to-next-to-leading order in a fully differential way.Comment: 5 pages, 2 figures, to appear in the proceedings of the 7th International Symposium on Radiative Corrections (RADCOR05), Shonan Village, Japan, 200

Passband flattened interleaver using a Mach- Zehnder interferometer with ring resonator fabricated in SiON waveguide technology.

A wavelength interleaver having almost rectangular wavelength response, with 50 GHz free spectral range has been demonstrated using SiON waveguide technology. The device consists of an asymmetric Mach-Zehnder Interferometer (MZI), with a ring resonator coupled to one of its branches. A passband flattened and stopband broadened transfer function with 15 dB isolation for TM polarized light (12 dB for TE) has been measured. The isolation was less than the designed 30 dB due to fabrication errors causing a deviation in coupling coefficient between MZI-branch and ring. The chromatic dispersion was measured to be zero in the center and 1660 ps/nm at the edge of the passband

Conformational behaviour of poly(2,6-dimethyl-1,4-phenylene oxide) in solution - I: Intrinsic viscosity as a function of temperature

Intrinsic viscosities [η] of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) solutions have been measured as a function of temperature between 60 and 25°C. The solvents were toluene and trichloroethene. In both solvents, the [η]-T curve exhibited a point of inflection in the range 45-35°. This phenomenon is explained as a conformational transition, which is possibly involved in the nucleation process of the solution crystallization of PPO. Assuming constancy of the coil expansion factor αη and the solvent draining over the whole temperature interval, a slight increase of characteristic parameter Cα, with decreasing temperature has been calculated