Approximating the traffic grooming problem in tree and star networks

We consider the problem of grooming paths in all-optical networks with tree topology so as to minimize the switching cost, measured by the total number of used ADMs. We first present efficient approximation algorithms with approximation factor of 2ln(δ⋅g)+o(ln(δ⋅g))$2ln(\delta \cdot g)+o(ln(\delta \cdot g))$ for any fixed node degree bound δ$\delta$ and grooming factor g$g$, and 2lng+o(lng)$2lng+o(lng)$ in unbounded degree directed trees, respectively. In the attempt to extend our results to general undirected trees, we completely characterize the complexity of the problem in star networks by providing polynomial time optimal algorithms for g≤2$g\le 2$ and proving the intractability of the problem for any fixed g>2$g>2$. While for general topologies, the problem was known to be NP-hard g$g$ not constant, the complexity for fixed values of g$g$ was still an open question.     

Measuring the Efficiency of the Intraday Forex Market with a Universal Data Compression Algorithm

Universal compression algorithms can detect recurring patterns in any type of temporal data—including financial data—for the purpose of compression. The universal algorithms actually find a model of the data that can be used for either compression or prediction. We present a universal Variable Order Markov (VOM) model and use it to test the weak form of the Efficient Market Hypothesis (EMH). The EMH is tested for 12 pairs of international intra-day currency exchange rates for one year series of 1, 5, 10, 15, 20, 25 and 30 min. Statistically significant compression is detected in all the time-series and the high frequency series are also predictable above random. However, the predictability of the model is not sufficient to generate a profitable trading strategy, thus, Forex market turns out to be efficient, at least most of the time.      

XFEM‐based crack detection scheme using a genetic algorithm

A new computational tool is developed for the accurate detection and identification of cracks in structures, to be used in conjunction with non‐destructive testing of specimens. It is based on the solution of an inverse problem. Based on some measurements, typically along part of the boundary of the structure, that describe the response of the structure to vibration in a chosen frequency or a combination of frequencies, the goal is to estimate whether the structure contains a crack, and if so, to find the parameters (location, size, orientation and shape) of the crack that produces a response closest to the given measurement data in some chosen norm. The inverse problem is solved using a genetic algorithm (GA). The GA optimization process requires the solution of a very large amount of forward problems. The latter are solved via the extended finite element method (XFEM). This enables one to employ the same regular mesh for all the forward problems. Performance of the method is demonstrated via a number of numerical examples involving a cracked flat membrane. Various computational aspects of the method are discussed, including the a priori estimation of the ill‐posedness of the crack identification problem. Copyright © 2007 John Wiley & Sons, Ltd.     

10 Gbit/s optical wavelength converter with a Brillouin scattering-based spectral filter

For the first time, to our knowledge, a highly robust, high-bit-rate (10 Gbit/s) wavelength converter that is based on a narrow Brillouin filter is reported. The conversion takes place in a semiconductor optical amplifier (SOA) in a cross-gain-phase process. The SOA operates in a weak-modulation mode, and the exiting signal undergoes a dc reduction with a narrow spectral filter. In our system we perform spectrally narrow filtering by using a long Brillouin grating.     

Hierarchical image representation for compression,filtering and normalization

Applications of pyramid data structure to image compression and image filtering are described. The compression scheme fits visual perception models, and filtering is computationally faster than filtering in the frequency domain. Image normalization is also possible.     

The effect of prolonged fasting and of glucose refeeding on rat serum and liver lipid levels

The effects upon serum lipids of prolonged fasting of rats followed by refeeding with glucose or chow was studied. Fasting caused a decrease in the levels of serum triglyceride, phospholipid and cholesterol ester, while the level of total cholesterol remained unchanged. Refeeding 20% glucose in water for one day after three days of fasting caused a significantly greater decrease in serum lipid levels than did an additional day of fasting, while refeeding chow for one day restored the serum lipid levels to normal. Seven days of fasting or one day of glucose refeeding following three days of starvation resulted in almost complete disappearance of all serum lipoprotein bands on paper electrophoresis. After four days of refeeding glucose to rats previously fasted for three days the serum lipid levels and lipoprotein patterns approached those seen in fed animals. Serum free fatty acids increased upon fasting, but after seven days of starvation their concentration dropped to that observed in the fed rats. Refeeding for one day with glucose or chow reduced the serum free fatty acid concentration to less than half of the starvation levels. Four days of starvation caused a great decrease in liver weight without causing very pronounced changes in the content of phospholipid and triglyceride in the whole liver; the cholesterol content, notably esterified cholesterol, decreased. Glucose feeding for one day after three days of starvation, while increasing liver weight, did not cause any appreciable change in the hepatic lipid content. Following the three days of starvation lipogenesis from glucose by liver slices is restored to the same extent by refeeding glucose or chow for one day. The role of liver, adipose tissue and diet in supplying fatty acids for serum lipids following fasting is discussed.     

A proposed industrial method for the removal of mercury from fish

An economically-feasible technique for the substantial reduction of the total mercury content of slices of tuna fish is described. Extraction at room temperature of the fish slices with 0.5 % cysteine hydrochloride solution is followed by rinsing and washing with sodium bicarbonate solution. The optimal conditions and recycling of the extraction solution are described. The organoleptic properties, protein quality and shelf life of the canned treated fish were satisfactory.     

Multichain Polyproline Coated with Histidyl and Glutamyl Residues — A Potent Synthetic Immunogen

A new, water soluble multichain polypeptide coated with short peptides containing histidyl and glutamyl residues was prepared, using the 2,4-dinitro-phenyl group for masking the imidazole imino-nitrogen during synthesis. The polymer obtained after thiolytic deblockage (multi-poly(L-histidyl, L-glutamyl)-poly-L-prolyl – – poly-L-lysine) was shown to be a potent synthetic immunogen, capable of provoking a high titer of antibodies in mice already at the primary response, and useful for studying the genetic control of the immune response.     

Vicissitudes of the impetus for growth and change among emerging adults.

The aim of this study was to understand why some emerging adults pursue their goals in effective ways while others become involved in projects or set goals that collapse after a period of time. In order to examine the inner processes which may explain this phenomenon, in-depth interviews were conducted with 70 emerging adults aged 21 to 26. The interviews revealed two main modes in the pursuit of goals among emerging adults. In the "doing-oriented" mode, individuals were extensively invested in a constant pursuit for its own sake, hardly thinking about what they do, and why. In contrast, in the "reflective-oriented" mode, emerging adults were highly reflective about their behaviors, motivations, and future projected plans. Integrating developmental and psychoanalytic thinking, our data propose new understandings of the inner processes through which emerging adults may experience and direct their lives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design of Light-Induced Molecular Switcher for the Driver of the Quantum Cellular Automata (QCA) Based on the Transition through the Intramolecular Charge Transfer (ICT) Structure

The design of light-induced switcher for the molecular QCA driver was discussed. The driver-cell with two connected chromophores was proposed as a basic model of the molecular light-induced trigger. One of the chromophores will conjugate with a left diagonal and the second chromophore will conjugate with a right diagonal. Some differences between two chromophores can allow selective controlling of the switch to the left or to the right. The following three-steps mechanism for QCA switcher was suggested – light-induced transition through ICT area (a), initiation of the driver‘s polarization (b) and the beginning of the signal transition to the other cells (c). The principal physical characteristics of the driver‘s trigger was proposed, and the corresponding chemical implementation was discussed. Three kinds of processes leading to ICT were discussed as mechanisms suggested for potential switchers: 1) Irradiation leading to the ICT excited state; 2) Chemical reaction with ICT transition state; 3) Excited State Intramolecular Proton Transfer (ESIPT). The common features of these processes are the non-radiative transition to the initial state after excitation, with the back transition going through the highly polar charge transfer (CT) area.