W‐band physical layer design issues in the context of the DAVID–DCE experiment

This paper aims at focusing on the aspects concerning the physical layer design for an innovative satellite communication experiment. Such an experiment, denoted by the acronym DAVID–DCE (Data and Video Interactive Distribution—Data Collection Experiment) is based on the exploitation of the W‐band (75–110 GHz) for high‐bit‐rate satellite transmission. The potential advantages of using of the W‐band are mainly related to the great bandwidth availability, and to the absence of interference. Moreover, an expected result of the experiment is a substantive improvement in the communication system's performances in the presence of meteorological phenomena (e.g. rain) as compared with the more conventional Ka‐band satellite transmission. On the other hand, problems to be faced concern the non‐ideal behaviours of hardware devices employed for high‐frequency digital transmission. In particular, carrier recovery and timing recovery are the most crucial signal‐processing tasks to be carefully considered in the design of the physical level of the system, because they considerably suffer from hardware impairments. The purpose of this work is to illustrate the proposed solutions in terms of the most critical modulation, demodulation and synchronization design issues, together with the effects of non‐ideal behaviours of hardware components on BER performances. Copyright © 2004 John Wiley & Sons, Ltd.     

Immobilization of an endopectinlyase on γ-alumina: Study of factors influencing the biocatalytic matrix stability

Endopectinlyase (EC 4.2.2.10) from Aspergillus japonicus was immobilized on to γ-alumina. Adsorption performed at pH 5·0 and a subsequent cross-linking phase using 0·1% glutaraldehyde were the chosen immobilization conditions. The comparison between the main biochemical parameters of the immobilized and free form of the enzyme showed that the immobilization procedure used did not affect the enzyme biochemical properties. The interactions between the carrier and the enzyme are essentially secondary bonding. In fact they depend on the pH and on the presence of phosphate ions in the medium. A tentative chemical model of the biocatalytic matrix thus obtained is proposed.     

The Lazy Cook Problem, or Scheduling Two Parallel Machines to Optimize Vehicle Utilization

A cook has to prepare n cakes using an oven with two racks. According to the recipe, the i-th cake has to be baked for exactly a _i minutes. Cakes to be cooked are taken from a table and carried to the oven, and once cooked are carried back to the table by means of a trolley that can carry two cakes at a time. What is the minimum number q ^* of round trips required of the cook? This problem has application to the operation scheduling of transportation systems and to material cutting. A different problem arises according to whether the cook accepts or not to stay near the oven for awhile with the trolley. If the trolley cannot be idle at the oven, an optimum schedule with no oven idle-time always exists: consequently, the trolley schedule is trivial, and the problem is transformed into a set packing. For this case, we propose and test a heuristic method which generates all of the promising columns of the set packing, and solves the resulting problem by branch-and-bound. Instead, if the trolley can be idle at the oven for a limited amount of time, a problem arises to find an optimal schedule of the trolley: in this case we show how to use a scaling technique in order to obtain a very good feasible solution by the method above.     

Attempted suicide among adolescents: A stepwise discriminant analysis.

A sample of 40 adolescents (aged 13–17 yrs), some of whom had attempted suicide (n?=?20) and some who had not (n?=?20), were compared on a number of life history and psychological variables (affective and cognitive). Stepwise discriminant analyses produced 1 discriminant function (the lack of emotional significant other) that differentiated between the groups. This single discriminant function accounted for 77% of the variance in the data. These results are interpreted within the context of the early loss hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SFG and DFG investigation of Au(111), Au(210), polycrystalline Au,Au–Cu and Au–Ag–Cu electrodes in contact with aqueous solutions containing KCN and 4-cyanopyridine

We report on potential-dependent in situ SFG and DFG spectroscopy carried out at Au(111), Au(210), polycrystalline Au, Au–Cu and Au–Ag–Cu electrodes in contact with aqueous solutions containing CN⁻ and 4-cyanopyridine (4CP). Spectroelectrochemical work was complemented by cyclic voltammetry. The chief stress has been placed on systematising and quantifying the interaction between 4CP and CN⁻ and the attending effects on the vibrational and electronic structures of the interface. The voltammetric behaviour of the investigated electrodes, modified by the addition of 4CP to the CN⁻ electrolyte, denote changes in the CN⁻ adsorption characteristics and effects of the adsorbed CN⁻ layer on the electrodic reactivity of 4CP. The differences among the investigated electrodes can be explained in terms of their respective degrees of atomic packing or with alloying effects on the stability of adsorbed CN⁻. The potential-dependent spectra have been analysed quantitatively with a model for the second order non linear susceptibility accounting for vibrational and electronic effects. The spectral changes induced by addition of 4CP denote interaction of the aromatic with the electrode through the CN⁻ monolayer. The non-resonant contribution yields information on the effects of 4CP on the fine structure of the bound electron density of states.     

意大利管材及异型材生产线技术的新发展

用合成材料生产的管道及产品将越来越多,随着要求的不断提高,推动研发工作的深入开展,其技术发展也在日新月异.这些也是法规所制定的高安全标准的结果,作为最终产品是必须要服从这些法规的.     

Robust estimation for circular data

The problems arising when there are outliers in a data set that follow a circular distribution are considered. A robust estimation of the unknown parameters is obtained using the methods of weighted likelihood and minimum disparity, each of which is defined for a general parametric family of circular data. The class of power divergence and the related residual adjustment function is investigated in order to improve the performance of the two methods which are studied for the Von Mises (circular normal) and the Wrapped Normal distributions. The techniques are illustrated via two examples based on a real data set and a Monte Carlo study, which also enables the discussion of various computational aspects.     

The Horace Method for Error-Correcting Codes

Here we apply the so-called Horace method for zero-dimensional schemes to error-correcting codes on complete intersections. In particular, we obtain sharper estimates on the minimum distance.     

Delay-bounded data gathering in urban vehicular sensor networks

Vehicular sensor networks are an emerging network paradigm, suitable for various applications in vehicular environment making use of vehicles’ sensors as data sources and Inter-Vehicle Communication systems for the transmissions. We present a solution, based on vehicular sensor networks, for gathering data from a certain geographic area while satisfying with a specific delay bound. The method leverages the time interval during which the query is active in order to make the gathering process efficient, properly alternating data muling and multi-hop forwarding strategies like in delay-bounded routing protocols. Simulations show that our proposed solution succeeds in performing efficient data gathering outperforming other solutions.