Tight analysis of the (1+1)-EA for the single source shortest path problem

We conduct a rigorous analysis of the (1+1) evolutionary algorithm for the single source shortest path problem proposed by Scharnow, Tinnefeld, and Wegener (The analyses of evolutionary algorithms on sorting and shortest paths problems, 2004, Journal of Mathematical Modelling and Algorithms, 3(4):349-366). We prove that with high probability, the optimization time is O(n2 max{?, log(n)}), where ? is the smallest integer such that any vertex can be reached from the source via a shortest path having at most ? edges. This bound is tight. For all values of n and ? we provide a graph with edge weights such that, with high probability, the optimization time is of order Ω(n2 max{?, log(n)}). To obtain such sharp bounds, we develop a new technique that overcomes the coupon collector behavior of previously used arguments. Also, we exhibit a simple Chernoff type inequality for sums of independent geometrically distributed random variables, and one for sequences of random variables that are not independent, but show a desired behavior independent of the outcomes of the previous random variables. We are optimistic that these tools find further applications in the analysis of evolutionary algorithms.     

Simple method for mitigation of polarization crosstalk in silica planar lightwave circuit directional couplers

Polarization crosstalk in planar lightwave circuit directional couplers can cause significant polarization-dependence in interferometers that use them. We show a simple way to mitigate the polarization crosstalk without incurring a performance penalty or requiring extra fabrication steps. We demonstrate it on a 23-ps Mach-Zehnder delay interferometer.     

On the interaction of electromagnetic fields with wire cagestructures

The authors address the problem of the interaction of electromagnetic fields with wire cage structures. The two canonical shapes considered are cubes and cylinders. The motivation for this work comes from a need to investigate electromagnetic field coupling (transient or broadband CW) to communication facilities or buildings with metallic rebar elements in the perimeter walls. Coupling calculations are performed by using NEC-2 computer codes and the experiments were performed at the Swiss MEMPS facility. MEMPS is a hybrid type of nuclear electromagnetic pulse (NEMP) simulator consisting of an impedance loaded elliptical structure with either a transient or a broadband CW excitation. Both types of excitations have been used in experimentally studying the coupling characteristics. In the case of cylindrical wire cage structures, both polarizations, i.e., incident electric field and incident magnetic field parallel to the cylinder axis, have been investigated. Good agreement is seen between the computed and measured result     

40-wavelength rapidly digitally tunable laser

We present a tunable laser based on an N₁×N₂ chirped waveguide grating router that has N₁N₂ wavelengths, accessible in a digitally rapid manner, and only N ₁+N₂+1 semiconductor optical amplifiers. By using chirp, the free-spectral range of the router can be significantly less than the channel span. The version demonstrated here has N₁=5, N₂=8, a channel spacing of 100 GHz, and the router free-spectral range is only 20 channels     

Compact and low-loss manner of waveguide grating router passbandflattening and demonstration in a 64-channel blocker/multiplexer

We present a compact design for flattening the passband of a waveguide grating router theoretically without excess loss or chromatic dispersion. We demonstrate its use in a 64-wavelength-channel blocker/multiplexer     

107-gb/s optical signal generation using electronic time-division multiplexing

This paper reports the first optical transmitter implementations operating at a serial bit rate of 107 Gb/s using solely electronic time-division multiplexing. Two methods to overcome modulator bandwidth limitations are proposed and demonstrated: low-bandwidth optical duobinary modulation and integrated optical equalization. Both transmitters are characterized in terms of bit error ratio and chromatic dispersion tolerance.     

107-Gb/s Serial Optical Packet Switching With 1-bit/s/Hz Spectral Efficiency for 100-GbE Backplanes

We demonstrate 107-Gb/s optical packet switching using electronically multiplexed duobinary signals, fast tunable lasers, and a 40 times 40 arrayed waveguide grating router. With a spectral efficiency of 1 bit/s/Hz, the fabric scales to 4-Tb/s capacity and is suitable for 100-Gb Ethernet backplanes.     

Serum hepatitis G virus (HGV) RNA in multitransfused thalassemics from eastern Sicily

To evaluate the efficacy of continuous administration of 50% nitrous oxide in oxygen for reducing pain during flexible fiberoptic bronchoscopy 32 children aged 3-60 months were randomly assigned to an experimental or a control group. Indications for endoscopy included persistent atelectasis (6), wheezing (10) cystic fibrosis (2) pneumonia (11) persistent cough (3). All patients received Midazolam (0.3 mg/kg) atropine (20 mcg/kg) intra rectaly 20 minutes before the procedure. The flexible fiberoptic bronchoscope (Olympus BF3C4) was inserted transnasally through a face mask. Topical anesthesia with 1% lidocaine hydrochloride (3 mg/kg) was applied to the nose, larynx, trachea and bronchial tree over 15 minutes through the suction chanel of the bronchoscope. All patients were monitored with a pulse oximeter and a cardiac monitor. The experimental group (n = 16) received 50% nitrous oxide in oxygen prior (3 minutes) and during flexible fiberoptic bronchoscopy, the control group (n = 16) received only oxygen. We measured pain of the children by a behavioral observation scale (Children's Hospital of Eastern Ontario Pain Scale: CHEOPS) at each phase of topical anesthesia during bronchoscopy in the two groups. At the end of bronchoscopy physician's satisfaction was scored by a visual analogue scale (VAS 0-100) in which 0 corresponded to absence of satisfaction. Nitrous oxide was associated with lesser pain scores than those with oxygen. Physician significantly preferred these procedure compared with oxygen. No complication occurred during procedure. Combined with local anesthesia midazolam and atropin the administration of 50% nitrous oxide in oxygen seems a better choice for flexible fiberoptic bronchoscopy in children and should be used routinely.     

Proposed WDM cross connect using a planar arrangement of waveguidegrating routers and phase shifters

We propose a reconfigurable wavelength-division-multiplexing (WDM) cross connect consisting of two “interleave-chirped” waveguide grating routers connected by waveguides with phase shifters. For the 2 line×2 line case, any wavelength channel in one line can be exchanged with the same wavelength channel in the other line. For the P line×P line case, the channels can be switched in a cyclical fashion between lines. The device is compact with no waveguide crossings; is predicted to have relatively low and even losses for all channels; can theoretically achieve very high, fabrication-tolerant, switching extinction ratios; and can theoretically achieve a nearly excess-loss-free rectangular spectral response