An application-specific protocol architecture for wireless microsensor networks

Networking together hundreds or thousands of cheap microsensor nodes allows users to accurately monitor a remote environment by intelligently combining the data from the individual nodes. These networks require robust wireless communication protocols that are energy efficient and provide low latency. We develop and analyze low-energy adaptive clustering hierarchy (LEACH), a protocol architecture for microsensor networks that combines the ideas of energy-efficient cluster-based routing and media access together with application-specific data aggregation to achieve good performance in terms of system lifetime, latency, and application-perceived quality. LEACH includes a new, distributed cluster formation technique that enables self-organization of large numbers of nodes, algorithms for adapting clusters and rotating cluster head positions to evenly distribute the energy load among all the nodes, and techniques to enable distributed signal processing to save communication resources. Our results show that LEACH can improve system lifetime by an order of magnitude compared with general-purpose multihop approaches.     

Organic Materials and Thin‐Film Structures for Cross‐Point Memory Cells Based on Trapping in Metallic Nanoparticles

Non‐volatile solid‐state memory cells based on composites of metal nanoparticles and polymers are embedded in organic semiconducting host materials. This paper presents data from a wide range of materials and device structures and shows that the switching phenomenon is commonly observed.     

Effects of extended dislocations on charge distribution in GaN epilayer

We have investigated the effect of extended dislocations (0.5-3 μm) on charge distribution in GaN epilayer grown by metalorganic chemical vapor deposition on (0001) sapphire using atomic force microscopy (AFM) and scanning surface potential microscopy (SSPM). It has been observed for the surface at the extended dislocations present in undoped GaN film to be negatively charged showing 0.04-0.2 V higher potential relative to regions that contain no dislocations. In addition to the higher potential at the dislocation core, the surrounding surfaces, including the edge of the dislocations, are also negatively charged in a symmetric way around the dislocations revealing crater-shaped higher potential regions (∼0.04 V) relative to surrounding dislocation-free area. The experimental results show that the protrusion-type of dislocation is also negatively charged and its potential is dependent on the size of dislocation.     

Influence of Edible Films upon the Moisture Loss and Microstructure of Dietetic Sucrose-Free Sponge Cakes during Storage

The kinetics of changes in the bound water content in dietetic sucrose-free sponge cakes (DC) during storage was investigated. The effect of edible films of polymyxan, pectin, xanthan, and carboxymethylcellulose upon this kinetics was also investigated. The quantitative changes in both states of water (slightly bound water and strongly bound water) were registered by combined dynamic analysis (thermogravimetry analysis, TGA, and differential thermal analysis, DTA). The moisture changes in DC crumb were analyzed by drying out to constant mass. The rate constants were determined according the equation q = q_oe^-kt. The values of rate constants 'k', in day^-1, concerning the different edible films were as follows: for crumb moisture is (8.00 ≤ k ≤ 12.47) × 10^-3, for bound water is (3.07 ≤ k_w ≤ 6.26) × 10^-2, for slightly bound water is (4.22 ≤ k₁ ≤ 8.49) × 10^-2 and for strongly bound water is (2.02 ≤ k₂ ≤ 5.62) × 10^-2 as compared to 18.53 × 10^-3, 7.16 × 10^-2, 9.04 × 10^-2, and 5.36 × 10^-2 in the uncovered DC, respectively. The best water-retaining effect in respect to crumb moisture during storage was ascertained in the use of polymyxan and xanthan films. The lowest rate constant values for bound water and its two states were measured for DC covered with pectin. The relation between the kinetics of both bound water states during storage and ageing of the crumb of DC covered with different edible films and the crumb microstructure was represented. By means of scanning electron microscope was read the smallest change in crumb microstructure of pectin-covered DC on the sixth day of storage.     

370 W output power GaN-FET amplifier for W-CDMA cellular base stations

A single-ended amplifier using small packaged GaN-FETs exhibits a record 2.14 GHz W-CDMA output power. The amplifier, composed of paralleled 48 mm gate periphery FET die, delivers a peak saturated output power of 371 W with a linear gain of 11.2 dB at a drain voltage of 45 V under 2.14 GHz 3GPP W-CDMA signal input. The output power density (output power/package size) of 1.1 W/mm/sup 2/ is twice as high as that of the existing over 300 W GaAs-FET amplifiers. A low 5 MHz offset ACLR of -36 dBc with a drain efficiency of 24% is also obtained at 8 dB power back off from the saturated output power.     

Reliability Potential Of Epoxy Based Encapsulants For Automotive Applications

Automotive under-the-hood electronics often have to withstand temperatures up to 175 °C in combination with harsh environment conditions. This paper gives an overview about the reliability potential of epoxy based encapsulants for automotive applications. Therefore the resistance of epoxy molding compound against typical automotive fluids at temperature of use is analyzed. Six epoxy molding compounds available on the market, showing high temperature automotive potential have been carefully selected to undergo a media resistance testing. For this purpose a dedicated mold tool has been designed and manufactured to prepare these encapsulants for material testing. Thermo-mechanical, mechanical and thermal properties had been determined in initial state directly after molding and after storage in aggressive fluids typical for automotive applications as e.g. gas oil, automatic transmission fluid (ATF), brake fluid or accumulator acid at the respective temperature of use.     

A Constraint-based Approach for Annotating Music Scores with Gestural Information

The physical gestures that operate music instruments are responsible for the qualities of the sound being produced in a performance. Gestural information is thereby crucial for a model of music performance, paired with a model of sound synthesis where this information is applied. The highly constrained nature of performers gestures makes this task suitable to be modeled via a constraint-based approach, coupled with a strategy aimed at maximizing the gestural comfort of performers. We illustrate the problem representation, the search strategy and a validation of the model against human performance.     

Formulation for Reliable Analysis of Structural Frames

Structural engineers use design codes formulated to consider uncertainty for both reinforced concrete and structural steel design. For a simple one-bay structural steel frame, we survey typical uncertainties and compute an interval solution for displacements and forces. The naive solutions have large over-estimations, so we explore the Mullen-Muhanna assembly strategy, scaling, and constraint propagation to achieve tight enclosures of the true ranges for displacements and forces in a fraction of the CPU time typically used for simulations. That we compute tight enclosures, even for large parameter uncertainties used in practice, suggests the promise of interval methods for much larger structures.