Mapping rule-based systems onto multicomputers using simulated annealing

In this paper, we present a static load balancing method for mapping production rules in an expert system onto processors of a message-passing multicomputer. The method uses simulated annealing to achieve a nearly optimal allocation of production rules onto processor nodes. The approach balances the initial rule distribution to avoid higher communication demand among processor nodes at run time. A formal mapping model is developed and a new cost function is defined for the annealing process. New heuristic swap functions and cooling policies are provided to ensure the quality of the annealing process. A software load balancing package, SIMAL, was implemented on a SUN workstation to carry out the benchmark experiments. The overhead associated with this mapping method is O(m In m), where m is the number of rules in the production system. Two benchmark production systems, Toru-waltz and Tourney, are mapped onto a hypercube computer with 32 nodes. Experimental benchmark results verify the effectiveness of the rule mapping method. The method can be applied for distributed artificial intelligence processing or for the parallel execution of cooperating expert systems on a message-passing multicomputer.     

Highly ordered microstructures of poly(styrene-b-isoprene) block copolymers induced by solution meniscus

Microstructures of hundreds of micron thick poly(styrene-block-isoprene) copolymer films solution-cast in a cylindrical tube with the solvent evaporation controlled were investigated by transmission electron microscope (TEM), small angle X-ray scattering (SAXS) and optical microscope (OM). In a block copolymer with cylindrical polyisoprene microdomains, the orientation of the cylinders was varied along radial direction of the cylindrical tube. Highly aligned hexagonal arrays of in-plane polyisoprene cylinders were formed with their cylindrical axis parallel to the circumference of the tube in the regimes close to the wall edge. In contrast randomly ordered microdomains were observed at the center of the tube. We have also found that the orientation depends on the solvent evaporation rate and an intermediate rate (∼2.3 nL/s) provides the best orientation. In the case of a block copolymer with a bicontinuous double gyroid structure, we obtained a globally ordered microstructure where [111] crystallographic direction was parallel to the circumference of the tube. For both block copolymers, the area of highly ordered arrays of nanoscopic domains is over 1 mm². Development of the orientation was explained by coupling two orthogonal fields: (1) The flow of a solution induced by strong capillary force at a meniscus between the cylindrical tube wall and the block copolymer solution and (2) the solvent evaporation.     

映射半解析边界元法解瞬态弹性动力问题的有关问题

提出了映射半解析边界元法解百轴对称瞬态弹性动力问题时存在解析方向不能正确反映波的传播现象的问题，产生该问题的原因和如何解决该问题的建议。     

弹性杆与水下壳体接触冲击的冲击力计算研究

对弹性杆与水下壳体接触冲击问题进行了研究，用有限元法模拟壳体，边界无法模拟无限域流体，通过温面上的耦合条件进行联立求解，文中给出了典型算例，并进行了有关讨论。     

Enhanced direct stiffness method for finite element analysis of textile composites

Traditional homogenization techniques are not useful when the microstructural scale of a material is of the same order of magnitude as the structural scale of a component. Such is the case for many textile composites. Since discrete modeling of the microstructure throughout a component is prohibitively expensive, continuum finite elements are needed which account for the microstructure within a single element. This paper describes a simple substructuring technique for formulating these special elements.     

Serum amyloid P component scintigraphy and turnover studies for diagnosis and quantitative monitoring of AA amyloidosis in juvenile rheumatoid arthritis

OBJECTIVE: To evaluate aspects of the natural history of AA amyloidosis complicating juvenile rheumatoid arthritis (JRA), and its response to therapy with chlorambucil. METHODS: Scintigraphy and 7-day turnover studies were performed in JRA patients with histologically proven (n = 35) or clinically suspected (n = 30) AA amyloidosis, following intravenous injection of 123I and 125I-labeled serum amyloid P component (SAP). Prospective monitoring studies were performed over 2-3 years in 20 patients with amyloidosis. All but 2 amyloidosis patients were treated with chlorambucil. RESULTS: Positive scanning results were obtained in all patients in whom imaging was performed within 12 years of positive biopsy findings of amyloid and in 5 patients with clinically suspected amyloidosis. Negative scanning results with normal SAP metabolism, indicating regression of amyloid, were obtained in 4 patients whose amyloidosis had been in full clinical remission for more than 12 years. Prospective monitoring studies in patients whose JRA-associated inflammatory activity was in remission demonstrated regression of amyloid in 8 patients and no substantial changes in 8 others; however, in 4 further patients with active inflammation, there was accumulation of amyloid. There was a very poor correlation between the amount of amyloid present at a particular site and the resultant organ dysfunction. CONCLUSION: Radiolabeled SAP scintigraphy and turnover studies are useful complementary tools in the diagnosis, screening, and quantitative monitoring of type AA amyloidosis in JRA. The amyloid deposits may progress and/or regress at different rates in different anatomic sites over short periods.     

A generalized suboptimum unequally spaced channel allocationtechnique. I. In IM/DD WDM systems

Four-wave mixing (FWM) is the most serious fiber nonlinearity associated with low-input optical power levels in long-haul multichannel optical systems employing dispersion-shifted fiber. To reduce the crosstalk due to FWM, a generalized suboptimum unequally spaced channel allocation (S-USCA) technique is proposed and investigated. Even though the developed technique is useful in combating FWM crosstalk in wavelength division multiplexing (WDM) lightwave systems with up to 12 channels, its main virtue is in designing multichannel WDM lightwave systems with more than 12 channels. Comparisons of power penalty due to FWM between equal channel spacing (ECS) systems and the S-USCA systems are presented. It is shown that for an intensity modulation/direct detection (IM/DD) transmission system operating in an optical bandwidth of 16 nm with 0 dBm (1 mW) peak optical input power per channel, while a conventional ECS WDM system with 0.84-nm channel spacing cannot even achieve a bit-error rate (BER)=10^-9, the suboptimum technique developed in this paper, for the same minimum channel spacing, can achieve a BER=10^-9 with an FWM crosstalk power of less than 1 dB at the worst channel in a 20-channel WDM system     

β-Si3N4Whiskers Embedded in Oxynitride Glasses: Interfacial Microstructure

Interfacial microstructures in βP-Si₃N₄( w )-Si-Al-Y-O-N-glass systems were investigated by systematically varying the nitrogen content and the Al:Y ratio of the glass matrix. High-resolution and analytical transmission electron microscopy (HREM and AEM) studies revealed that the interfacial microstructure is a function of the glass composition. No interfacial phases were formed in glasses with low Al:Y ratios and in glasses with high Al:Y ratios and low nitrogen content, whereas epitaxial growth of an interfacial layer (100–200 μm thick) on the βP-Si₃N₄( w ) occurred in a glass matrix with high Al:Y ratio and high nitrogen content. The interfacial layer was identified to be a β'-SiAION phase. Interfaces containing the SiAION layer exhibited high debonding energy compared to Si₃N₄( w )–glass interfaces. HREM studies indicated that the lattice-mismatch strain in the SiAION layer was relieved by dislocation formation at the SiAION–Si₃N₄( w ) interface. The difference in interfacial debonding energy was, hence, attributed to the local atomic structure and bonding between the glass-β-Si₃N₄ and the glass–β'-SiAION phases. This observation was clear evidence of the strong influence of glass chemistry on the interfacial debonding behavior by altering the interfacial microstructure.