Automation and intelligent scheduling of distributed system functional testing

International Journal on Software Tools for Technology Transfer - This paper presents the approach to functional test automation of services (black-box testing) and service architectures (grey-box...     

Dynamic output feedback linearization and global stabilization

We present a class of single-input single-output nonlinear systems which are globally transformable by a dynamic output feedback control and a time-varying state space transformation into a linear, observable and minimum phase system. We then show how those systems can be globally stabilized by a dynamic output feedback nonlinear control and how global output tracking can be achieved as well.     

Dopant Distributions in Rare-Earth-Doped Alumina

The distribution of yttrium and lanthanum dopants has been mapped in yttrium- and lanthanum-doped polycrystalline aluminas using imaging secondary-ion mass spectrometry (imaging-SIMS). Both dopants segregate to grain boundaries and pore surfaces. On average, yttrium occupies 7.1%–9.0% of the available grain-boundary cation sites, whereas lanthanum occupies only 2.0%–5.2%. In 1000-ppm-yttrium-doped alumina, an abundance of yttrium aluminum garnet precipitates also is observed. Implications of these observations to the creep behavior of alumina are discussed. The similarity in the segregation behavior of yttrium and lanthanum highlights the potential of lanthanum-doped alumina for improved creep properties.     

On the angular-spectrum representation of multipole wave fields

The closed-form expression of the angular spectrum of multipole fields, both scalar and vectorial, of any order and degree, evaluated across a plane orthogonal to an arbitrary (fixed) direction, is provided. Such a result has been obtained by starting from the Weyl representation of multipole fields and using suitable transformation rules. Moreover, as far as the vectorial case is concerned, knowledge of the (vectorial) transverse angular spectrum allows one to gain some insight into the polarization structure of the multipole fields evaluated across a typical plane. Such information could be useful, for instance, in those problems dealing with the interaction between planar partially reflecting surfaces and waves.     

Intracellular calcium and protein tyrosine phosphorylation during the release of bovine sperm adhering to the fallopian tube epithelium in vitro

In mammals, sperm adhesion to the epithelial cells lining the oviductal isthmus plays a key role in the maintenance of motility and in the selection of superior quality subpopulations. In the bovine species, heparin and other sulfated glycoconjugates powerfully induce the synchronous release of sperm adhering to tubal epithelium in vitro and may represent the signal which triggers release at ovulation in vivo. Sperm detachment may be due either to surface remodeling or to hyperactivation brought about by capacitation. In this paper, the dynamics of intracellular free Ca2+concentration ([Ca2+]i) and protein tyrosine phosphorylation in sperm during and after heparin-induced release from in vitro cultured oviductal monolayers were assessed to determine whether this event is due to capacitation. Moreover, Ca2+-ionophore A23187, thapsigargin, thimerosal and caffeine were used to determine whether [Ca2+]i increase and/or hyperactivation can induce sperm release. Results showed that: 1. heparin-released sperm have significantly higher [Ca2+]i than adhering sperm; 2. heparin induces a [Ca2+]i elevation in the sperm head followed by detachment from the monolayers; 3. external Ca2+is not required for heparin-induced release; 4. [Ca2+]i increase and/or hyperactivation are unable to release sperm; and 5. heparin-released sperm have an increased level of tyrosine phosphorylated proteins compared with adhering sperm. In conclusion, although heparin is considered a long-lasting capacitation agent, it quickly modulates the capacitation of bovine sperm adhering to the fallopian epithelium, probably leading to surface remodeling and therefore to the release of sperm selected and stored within the oviduct through adhesion.     

Coherent-mode decomposition of partially polarized,partially coherent sources

It is shown that any partially polarized, partially coherent source can be expressed in terms of a suitable superposition of transverse coherent modes with orthogonal polarization states. Such modes are determined through the solution of a system of two coupled integral equations. An example, for which the modal decomposition is obtained in closed form in terms of fully linearly polarized Hermite Gaussian modes, is given.     

Incremental adaptive equalizers using ternary +1, 0, −1 tap coefficients and/or delta modulation input encoding

In this paper a new approach to fractionally-spaced adaptive equalization is presented, which uses for the input and/’or the impulse response of the filter a delta modulation — type incremental encoding with a substantially reduced number of bits (binary + 1, ? 1 or ternary + 1, 0, ? 1 representation). When the oversampling factor is of the order of few tens, performance of these equalizers is comparable to that of the corresponding non-incremental equalizers with oversampling factor of few units. This approach to adaptive equalization appears promising for implementation simplicity in both filtering and control algorithms.     

Local orthogonal bases II: Window design

In the first part of this work we presented a technique to find a local orthogonal basis for a given vector space. The concept of a local orthogonal basis can be seen as an extension of the one-dimensional local cosine basis used, for example, in audio processing. Here the problem of window design is discussed, with a particular emphasis on the two-dimensional case, both in continuous and discrete time.     

Effectiveness and limits of magnetic resonance techniques in the identification of different coordination pathways of the Mn(II) in the presence of biomacromolecules

Summary Magnetic resonance techniques yield important information on different coordination behaviour of Mn(II) in the presence of biomacromolecules. A preliminary study on model systems is necessary to have a deeper insight on dynamics and structural aspects.The EPR technique is not able to identify a binding interaction between Trp and manganous ion when the metal is bonded to the Imidazole. Proton shift NMR studies on the Mn(II)-5ATP-Imid complex evidenziate a ternary system formation and a stacking interaction between the imidazole-ring and the nucleotide purine-moiety.An EPR and NMR combined analysis on the Mn(II)-5ATP-Trp system points out a stacking interaction and the simultaneous presence of a covalent binding between the metal ion and the biomolecules. The role of the metal ion to favour this coordination is suggested.Presented at the 22nd Microsymposium, Characterization of Structure and Dynamics of Macromolecular Systems by NMR Methods, Prague, July 20–23, 1981     

Fundamental Limits of Electronic Signal Processing in Direct-Detection Optical Communications

Electronic signal processing is becoming very attractive to overcome various impairments that affect optical communications, and electronic dispersion compensation (EDC) represents a typical application in the currently designed systems. However, the inherent limits in performance achievable by electronically processing the signal at the output of a nonlinear photodetector have not received the attention they deserve. In this paper, we investigate the information-theoretic limits of electronic signal processing in transmission systems employing direct photodetection and two possible modulation formats: 1 on-off keying (OOK) with nonreturn-to-zero pulses; and 2 optical duobinary modulation (ODBM). The analysis is based on the computation of the information rate, i.e., the maximum achievable data transfer rate, and accounts for the modulation format as well as relevant parameters of the transmission scheme. In particular, we investigate the impact of sampling rate, uncompensated chromatic dispersion (CD), and quantization resolution of the electrical signal at the output of a direct photodetector. For OOK systems, the obtained results show that the optical signal-to-noise ratio penalty entailed by EDC can be limited to about 2 dB at most values of CD of interest in current applications. Moreover, ODBM systems at high values of CD can almost perform as OOK systems at zero CD. For all the considered modulation formats, the obtained results show that the received electrical signal can be sampled at a rate of two samples per bit interval and quantized with a precision of 3 bits per sample to practically achieve the ultimate performance limits.