Effect of reliability on the efficiency of communication systems

Reliability consideration of performance systems is an important problem of today. The results obtained by using the well known theoretical foundations of reliability are not sufficient. Therefore a new reliability concept for performance systems is developed. A main aspect of this concept is to use the reliability as an independent variable while system efficiency is used as a dependent variable. The introduced concept is illustrated with the help of a parallel structure as well as a nonseries parallel structure.     

Determination of alpha activity ratios by alpha spectrometry in the presence of large amounts of uranium

A direct evaporation method is described for the preparation of sources using stainless steel as the backing material and tetraethylene glycol (TEG) as a spreading agent in the presence of large amounts of uranium. It is shown that FWHM and tail contribution at the low energy peak due to energy degradation of the high energy peak can be optimized by heating the source under controlled conditions in a furnace at 500–600°C for about 15 min. An accuracy of 0.5–1% is demonstrated for the determination of²³⁸Pu/(²³⁹Pu+²⁴⁰Pu) alpha activity ratio in the U/Pu range of 10 to 1500 generally encountered in dissolver solution of irradiated fuel.     

A random 1-011-011-01algorithm for depth first search

In this paper we present a fast parallel algorithm for constructing a depth first search tree for an undirected graph. The algorithm is anRNC algorithm, meaning that it is a probabilistic algorithm that runs in polylog time using a polynomial number of processors on aP-RAM. The run time of the algorithm isO(T _MM(n) log³ n), and the number of processors used isP _MM (n) whereT _MM(n) andP _MM(n) are the time and number of processors needed to find a minimum weight perfect matching on ann vertex graph with maximum edge weightn.This research was done while the first author was visiting the Mathematical Research Institute in Berkeley. Research supported in part by NSF grant 8120790.Supported by Air Force Grant AFOSR-85-0203A.     

On the computation of motion from sequences of images-A review

Recent developments are reviewed in the computation of motion and structure of objects in a scene from a sequence of images. Two distinct paradigms are highlighted: (i) the feature-based approach and (ii) the optical-flow-based approach. The comparative merits/demerits of these approaches are discussed. The current status of research in these areas is reviewed and future research directions are indicated     

Determination of software release instant using a nonhomogeneous error detection rate model

The nonhomogeneous error detection rate model has been extensively used in software reliability modelling. An important management responsibility is to make a decision about the release of software, so as to result in maximum cost effectiveness. It is well known that the effort for correction of an error increases, rather heavily, from an initial testing phase to a final testing phase and then to the operational phase. In this paper, a method is presented to systematically determine this optimum release instant. The fact that some faults can be regenerated during the process of correction has also been considered in the modelling—this has been ignored in previous literature. Also, the partition of the testing phase into initial and final phases is considered to be desirable as effort per error correction will be significantly different in these two phases. An example illustrates the entire procedure for various values of the total number of errors and the trends of cost and release time.     

A fast algorithm for the performance index of a telecommunicationnetwork

A performance index for a telecommunication network is defined as a composite index integrating the important measures of both reliability and capacity. In this index the network states that permit a flow capability less than the maximum, are not totally ignored but are assigned a normalized weight less than one. A fast method is proposed for deriving the symbolic expression of the performance index in a compact form. Because the capacity of several subnetworks must be computed, an efficient procedure for capacity determination is also suggested. An example illustrates the procedure and points out the simplicity of the resulting expression for the performance index     

A highly integrated dual-band triple-mode transmit IC for cellular CDMA2000 applications

A highly integrated transmit integrated circuit intended for dual-band (CELL/PCS) and triple-mode (CDMA/TDMA/AMPS) cellular mobile stations is presented. It features a linear-in-dB gain-control range of 90 dB and provides a high output power of 9 dBm (PCS band) while meeting linearity requirements (-53-dBc ACPR) and achieving the receive-band noise floor of -133 dBm/Hz. It consumes only 130-mA current (3-V supply) in the PCS band. A dynamic-biasing feature results in additional power savings at lower signal levels. The circuit is fabricated in a 30-GHz f/sub T/ BiCMOS technology.     

Event-by-event search for charged-neutral fluctuations in Pb-Pb collisions at 158 A⋅GeV

We analyse the proton electromagnetic form factor ratioR(Q ² ) =QF ₂ (Q ² )/F ₁ (Q ² ) as a function of momentum transferQ ² within perturbative QCD. We find that the prediction for (R(Q ² ) at large momentum transferQ depends on the exclusive quark wave functions, which are unknown. For a wide range of wave functions we find thatQF ₂ F ₁ ～ const. at large momentum transfer, which is in agreement with recent JLAB data.     

Preparation and characterization of heterobimetallic tetraxanthates and their complexes with Lewis bases

Some new heterobimetallic tetraxanthates of the type M[Ag(Etxant)₂]₂ [M = Co(II) or Ni(II), Etxant = ethylxanthate] and their complexes of general formula M[Ag(Etxant)₂]₂.xL [x = 2 when L= dimethylsulphoxide (DMSO), triphenylphosphine (Pph₃), pyridine(py) or 2-aminopyridine (2-ampy); x = 3 when L = 2,2′-bipyridine (bipy)] have been prepared and characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. Magnetic and electronic spectral studies indicate square planar geometry around Ni(II) and Co(II) in heterobimetallic tetraxanthates and Ni[Ag(Etxant)₂]₂.2PPh₃ and octahedral geometry around the above metal ions in the remaining complexes.