Agents in industry: the best from the AAMAS 2005 industry track

Agent technology provides industrial-applications developers with new abstractions for distributed-system development, new methodological tools, and a set of algorithms for creating autonomous, collaborative systems. Over the past few years, a number of industrial applications have deployed agents. However, a substantial gap still exists between the cutting-edge research carried out mainly in university laboratories and research institutes and the domain-specific industrial applications that commercial organizations develop. This article gives some indication of agent technology's readiness for commercial deployment, based primarily on the presentations and discussions at the inaugural Industry Track of AAMAS 2005 - the Fourth International Joint Conference on Autonomous Agents and Multiagent Systems.     

Finite difference solution of one-dimensional Stefan problem with periodic boundary conditions

A finite difference method is used to solve the one-dimensional Stefan problem with periodic Dirichlet boundary condition. The temperature distribution, the position of the moving boundary and its velocity are evaluated. It is shown that, for given oscillation frequency, both the size of the domain and the oscillation amplitude of the periodically oscillating surface temperature, strongly influence the temperature distribution and the boundary movement. Furthermore, good agreement between the present finite difference results and numerical results obtained previously using the nodal integral method is seen.     

Fundamentals of dynamic frequency hopping in cellular systems

We examine techniques for increasing spectral efficiency of cellular systems by using slow frequency hopping (FH) with dynamic frequency-hop (DFH) pattern adaptation. We first present analytical results illustrating the improvements in frequency outage probabilities obtained by DFH in comparison with random frequency hopping (RFH). Next, we show simulation results comparing the performance of various DFH and RFH techniques. System performance is expressed by cumulative distribution functions of codeword error rates. Systems that we study incorporate channel coding, interleaving, antenna diversity, and power control. Analysis and simulations consider the effects of path loss, shadowing, Rayleigh fading, cochannel interference, coherence bandwidth, voice activity, and occupancy. The results indicate that systems using DFH can support substantially more users than systems using RFH     

Three-dimensional observation of wound temperature in primary healing

In a group of 30 patients the temperature in the epigastric region was followed pre-operatively for four days. After upper medial laparotomy the temperature of the wound and its surroundings was followed during eight post-operative days. Thus every examinee was a control to himself. The temperature was measured on AGA 780 thermovision system. The advantages of thermovision in observing temperature in primary healing are manifold. The method is painless, non-contact, thereby decreasing the risk of contamination from outside, gives an absolutely accurate image of temperature over a larger or smaller area, and analysis of the thermogram is relatively simple. The defining of the healing process as thermal change in intensity, extensiveness and time is, in essence, three-dimensional. It gives the possibility of accurate indirect observation of biochemical and chemico-physical changes in the wound and its surroundings.     

Ba1−xPrxCo1−yFeyO3−δ as cathode materials for low temperature solid oxide fuel cells

Ba_1−xPr_xCo_1−yFe_yO_3−δ (BPCF) perovskite oxides have been synthesized and investigated as cathode materials for low temperature solid oxide fuel cells (LT-SOFCs). Compared with those of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF) and Sm_0.5Sr_0.5CoO₃ (SSCo) cathode materials, BPCF has a lower polarization resistance at decreased temperatures. In particular, Ba_0.5Pr_0.5Co_0.8Fe_0.2O_3−δ showed the lowest polarization loss among the different compositions as a cathode material for LT-SOFCs. The area specific resistance (ASR) of Ba_0.5Pr_0.5Co_0.8Fe_0.2O_3−δ as a cathode material is 0.70 and 0.185 Ω cm² at 500 °C and 550 °C, respectively. The maximum power density of the cell BPCF/SDC/Ni-SDC with humidified hydrogen as fuel and air as oxidant reaches 860 mW cm⁻² at 650 °C.     

Thermal behavior of silver nanoparticles for low-temperature interconnect applications

Low-temperature sintering behavior of Ag nanoparticles was investigated. The nano Ag particles used (∼20 nm) exhibited obvious sintering behavior at significantly lower temperatures (∼150°C) than the T_m (960°C) of silver. Coalescence of the nano Ag particles was observed by sintering the particles at 150°C, 200°C, and 250°C. The thermal profile of the nanoparticles was examined by a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA). Shrinkage of the Ag-nanoparticle compacts during the sintering process was observed by thermomechanical analysis (TMA). Sintering of the nanoparticle pellet led to a significant increase in density and electrical conductivity. The size of the sintered particles and the crystallite size of the particles increased with increasing sintering temperature.     

Capacity of Interference Channels With Partial Transmitter Cooperation

Capacity regions are established for several two-sender, two-receiver channels with partial transmitter cooperation. First, the capacity regions are determined for compound multiple-access channels (MACs) with common information and compound MACs with conferencing. Next, two interference channel models are considered: an interference channel with common information (ICCI) and an interference channel with unidirectional cooperation (ICUC) in which the message sent by one of the encoders is known to the other encoder. The capacity regions of both of these channels are determined when there is strong interference, i.e., the interference is such that both receivers can decode all messages with no rate penalty. The resulting capacity regions coincide with the capacity region of the compound MAC with common information.     

Suspension HVOF Spraying of Reduced Temperature Solid Oxide Fuel Cell Electrolytes

Metal-supported solid oxide fuel cells (SOFCs) composed of a Ce_0.8Sm_0.2O_2?δ (SDC) electrolyte layer and Ni-Ce_0.8Sm_0.2O_2?δ (Ni-SDC) cermet anode were fabricated by suspension thermal spraying on Hastelloy × substrates. The cathode, a Sm_0.5Sr_0.5CoO₃ (SSCo)-SDC composite, was screen-printed and fired in situ. The anode was produced by suspension plasma spraying (SPS) using an axial injection plasma torch. The SDC electrolyte was produced by high-velocity oxy-fuel (HVOF) spraying of liquid suspension feedstock, using propylene fuel (DJ-2700). The emerging technology of HVOF suspension spraying was explored here to produce thin and low-porosity electrolytes in an effort to develop a cost-effective and scalable fabrication technique for high-performance, metal-supported SOFCs. In-flight particle temperature and velocity were measured for a number of different gun operating conditions and standoff distances and related to the resulting microstructures. At optimized conditions, this approach was found to limit material decomposition, enhance deposition efficiency, and reduce defect density in the resulting coating, as compared to previous results reported with SPS. Produced button cells showed highly promising performance with a maximum power density (MPD) of 0.5 W cm^?2 at 600 °C and above 0.9 W cm^?2 at 700 °C, with humidified hydrogen as fuel and air as oxidant. The potential of this deposition technique to scale-up the substrate size to 50 × 50 mm was demonstrated.