A Highly Digital MDLL-Based Clock Multiplier That Leverages a Self-Scrambling Time-to-Digital Converter to Achieve Subpicosecond Jitter Performance

This paper presents a mostly digital multiplying delay-locked loop (MDLL) architecture that leverages a new time-to-digital converter (TDC) and a correlated double-sampling technique to achieve subpicosecond jitter performance. The key benefit of the proposed structure is that it provides a highly digital technique to reduce deterministic jitter in the MDLL output with low sensitivity to mismatch and offset in the associated tuning circuits. The TDC structure, which is based on a gated ring oscillator (GRO), is expected to benefit other PLL/DLL applications as well due to the fact that it scrambles and first-order noise shapes its associated quantization noise. Measured results are presented of a custom MDLL prototype that multiplies a 50 MHz reference frequency to 1.6 GHz with 928 fs rms jitter performance. The prototype consists of two 0.13 mum integrated circuits, which have a combined active area of 0.06 mm² and a combined core power of 5.1 mW, in addition to an FPGA board, a discrete DAC, and a simple RC filter.     

Interaction of pesticides with humic compounds and their metal complexes

The interaction of pesticides with humic compounds (humic and fulvic acids) and with their metal complexes was studied potentiometrically and radiometrically, using the pesticides Aldicarb and Methomyl, and the herbicide Ametryne. The metal humate or fulvate complexes were prepared by precipitation of the complexes using Co²⁺, Zn²⁺, or Sr²⁺. The results indicated that Aldicarb, Methomyl, and Ametryne form stable complexes with humic acid (HA) and fulvic acid (FA). The complexation strength increases in the order Aldicarb ≤ Methomyl < Ametryne. The complexes of Aldicarb and Methomyl with HA and FA are stronger than the metal humate/fulvate complexes with Co²⁺, Zn²⁺, and Sr²⁺, and these pesticides displace the metal ions. Ametryne adds to the metal humate/fulvate by physical adsorption or ligand exchange. The complexation of Aldicarb and Methomyl with humic compounds causes the release of radionuclides (⁶⁰Co, ⁶⁵Zn, ⁹⁰Sr) from the soil organic matter to the solution. The pH exerts a decisive effect on the complexation of the pesticides with humic compounds. Published in Russian in Radiokhimiya, 2006, Vol. 48, No. 4, pp. 377–383. The text was submitted by the authors in English.     

Universal interactions with smart spaces

A critical challenge facing the pervasive computing research community is the need to manage complex interactions among numerous interconnected computers and devices. In such a pervasive space, a given application's functionalities are partitioned and distributed across several computing devices that are spontaneously discovered and used. In recent years, researchers have devoted much attention to universal interactions with diverse devices in richly networked settings. We can categorize the numerous approaches explored into two groups: universal user interface languages and user interface remoting. We review recent noteworthy efforts for universal interactions using these two approaches. Such efforts aim to raise interoperability in interactive smart spaces by standardizing user interface languages or communication protocols.     

Single-chip CMOS pulse generator for UWB systems

This paper presents a single-chip pulse generator developed for Ultra Wide Band (UWB) wireless communication systems based on impulse radio technology. The chip has been integrated in a CMOS 130-nm technology with a single supply voltage of 1.2 V. The basic concept is to combine different delayed edges in order to form a very short duration "logical" pulse, and then filter it, so as to obtain an UWB pulse. It is possible to vary the output pulse shape, and thus the corresponding spectrum, just by acting on the delayed edge combination. Furthermore, the pulse generator supports both position modulation (2-PPM) and polarity modulation (BPSK modulation) in order to convey data through the air. Its power consumption remains less than 10 mW for a raw data rate of up to 160 Mb/s. Spectral and temporal measurements of the single-chip pulse generator are presented with an illustration of the modulation effects on the power spectral density (PSD).     

Chemical and aroma volatile compositions of date palm (Phoenix dactylifera L.) fruits at three maturation stages

The effect of maturity stage on the physicochemical composition and volatile components of date palm fruits (Phoenix dactylifera L.) was investigated at three different stages. Total sugars, pH, proteins and ash increased up to the full-ripe stage of all date types. On the contrary, weight, moisture and total lipids decreased across the same period. Pearson’s test established significant differences (p < 0.05) between the different cultivars at each stage for all the parameters. Furthermore, multivariate tests show that the composition and the variation of the chemical compositions mainly depended on the cultivar kind. Eighty volatile compounds were identified during the maturation stages, 43 of them were newly identified in Tunisian date fruits. The profiles of volatile compounds seem to be similar for Degla and Horra varieties. Results from this work revealed essential information about the richness of littoral cultivars in many nutrients and the possibility of their uses as a functional food ingredient.     

A simple detector for trellis-coded PSK mobile radio systems

A simple detector for a trellis-coded PSK mobile radio system is proposed. A precoder is added to the regular TC-PSK modulator before convolution coding, and a simple one-bit differential detector is used in the receiver. The decision is made symbol by symbol based on the output samples. The bit error rate of this system is evaluated in fast Rayleigh fading characterizing mobile radio channels by numerical integration.     

Cylinder deceleration in an infinite viscous fluid of finite density

The retardation of the rotation of a cylinder in an infinite viscous fluid of finite density is investigated. The retardation occurs due to the action of the viscous shear and the inertia force. The results introduce the angular velocity of the cylinder ω(t) in the form:

.     

HiCoMo: High Commit Mobile Transactions

We introduce a new mobile transaction model applicable to decisionmaking applications over aggregate data warehoused on mobile hosts. The model allows the aggregate data to be updated in disconnection mode, while guaranteeing a very high rate of commitment on reconnection. We name such transactions High Commit Mobile Transactions, or HiCoMo. At reconnectiontime, HiCoMo's are analyzed and several base (fixed network) transactions are generated in order to bring the same effect upon the base tables from which the aggregates are derived. In this paper, we provide a formal definition for the concepts related to HiCoMo's, and a transformation algorithm that is used to analyze them and generate base transactions. We provide a simple example scenario to demonstrate the usefulness of this transaction model. Finally, we compare the commit behavior of HiCoMo's to that of the two-tier model using simulation and a mobile transaction benchmark drawn from an inventory application domain.     

Object technology. A virtual roundtable

Heralded by many as a promising solution to software complexity, object technology is coming into its own. This article explores some recent trends, including distributed objects, object-oriented databases (OODBs), parallel computing, software testing and theoretical foundations     

Optimal design of hybrid RO/MSF desalination plants Part II: Results and discussion

This paper presents the results of an optimization study, based on minimum water cost, to explore the feasibility of the hybridization of RO and MSF processes. The study explores the possible improvement of MSF process economics. Nine different scenarios for the production of the same capacity of desalted water are presented and compared from the standpoint of minimum water cost, specific capital cost and water recovery. The process and cost models, formulation of the optimization problem and solution outlines were previously presented in the first part of this study. In this work, results show that RO technology is recommended when building new desalination plants. RO technology becomes preferable at low feed concentrations and for brackish water desalination. Although they come in second position after the RO process, some hybrid plants economically exceed by far the MSF process. Computations gave a water cost of 1.1 $/m³ for the brine recycle MSF process against 0.75 $/m³ for the two-stage RO process. Water cost of the MSF process can be reduced by 17 to 24% through hybridization with RO technology.