Building a Language‐Independent Discourse Parser using Universal Networking Language

Discourse parsing has become an inevitable task to process information in the natural language processing arena. Parsing complex discourse structures beyond the sentence level is a significant challenge. This article proposes a discourse parser that constructs rhetorical structure (RS) trees to identify such complex discourse structures. Unlike previous parsers that construct RS trees using lexical features, syntactic features and cue phrases, the proposed discourse parser constructs RS trees using high‐level semantic features inherited from the Universal Networking Language (UNL). The UNL also adds a language‐independent quality to the parser, because the UNL represents texts in a language‐independent manner. The parser uses a naive Bayes probabilistic classifier to label discourse relations. It has been tested using 500 Tamil‐language documents and the Rhetorical Structure Theory Discourse Treebank, which comprises 21 English‐language documents. The performance of the naive Bayes classifier has been compared with that of the support vector machine (SVM) classifier, which has been used in the earlier approaches to build a discourse parser. It is seen that the naive Bayes probabilistic classifier is better suited for discourse relation labeling when compared with the SVM classifier, in terms of training time, testing time, and accuracy.     

Practical and scalable evolution of digital circuits

This paper addresses the scalability problem prevalent in the evolutionary design of digital circuits and shows that Evolvable Hardware (EHW) can indeed be considered as a viable alternative design methodology for large and complex circuits. Despite the effort by the EHW community to overcome the scalability problems using both direct mapped techniques and developmental approaches, so far only small circuits have been evolved. This paper shows that, by partitioning a digital circuit and making use of a modular developmental approach, namely, the Modular Developmental Cartesian Genetic Programming (MDCGP) technique, it is indeed possible to evolve large circuits. As a proof of concept, a 5 × 5 multiplier is evolved for partition sizes of 32 and 64. It is shown that compared to the direct evolution technique, the MDCGP technique provides five times reduction in terms of evolution times, 6–56% reduction in area and improved fault tolerance. The technique is readily scalable and can be applied to even larger partition sizes, and also to sequential circuits, thus providing a promising path to evolve large and complex circuits.     

Anion structural effects on interaction of rare earth element ions with Dowex 50W X8 cation exchange resin

The effect of the anion in the original rare earth element(REE) solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared(ATR-IR) spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy(ICP-MS), and density functional theory(DFT). The simulated IR spectrum at the DFT B3 LYP/6-31 G(d) level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion(SO_4~((2-)) or NO_3~((-))) associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy(BE) and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2~((3+))2 SO_4~((2-)) and Ce~((3+)) 3 NO_3~((-)). These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site(H+) in the Dowex 50 W X8 with the NH_4~+ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.     

A survey of imperatives and action representation formalisms

Representation and reasoning of actions is a wide spread area in the domain of Artificial Intelligence. The representation involves natural language instructions, which are based on the linguistic concepts and the reasoning methodology deals with the logical structures. In the computational domain, several theories pertaining to the state-space approach have been proposed to represent and reason out actions. Considering these aspects, this paper provides an account of work from the viewpoint of linguistics, logic and action representation formalisms. Based on this study, this paper then proposes a seven axes categorization scheme, that can be used to compare and analyze different theories.     

Surface Characterization of Ti and Ti (6% AI-4%, V) Metal Powders and Interaction with Primer Solutions

The surfaces of Ti and Ti (6% Al-4% V) powders were characterized by several techniques. BET surface areas as a function of temperature were measured using nitrogen adsorption. Heats of immersion (δ_wH) of these metal powders in water were measured after evacuation over the temperature range 100°–400°C. The δ_wH in water increased with increasing evacuation temperature and an anomalous increase was observed between 300° and 400°C. This was attributed to exposure of water to elemental titanium by cracking of the oxide layer at 400°C. XPS analysis did not support the possibility of metal migration through the oxide layer. Higher heats of immersion in water were determined for chemically pretreated compared to untreated Ti 6–4 powders. Water vapor adsorption isotherms were measured after evacuation of the metal powders at 100°C. Partial irreversibility of the water adsorption was observed on both powders. Water adsorption on Ti was temperature dependent. Heats of immersion measurements were used to study the interaction of primer solutions with these metal powders. Polyimide (LARC-13) and polyphenylquinoxaline (PPQ) interacted preferentially compared to the solvents with both powders. This polymer-metal interaction improved significantly after pretreatment of the Ti 6–4 powder by the Turco® 5578 and phosphate-fluoride processes. Again, an anomalous increase in the heat of immersion of Ti 6–4 evacuated at 400°C in the primer solution/solvents was observed. Anatase and rutile TiO₂ powders are not satisfactory models for the surface oxide layer on either Ti or Ti 6–4 powders.     

A classification of studies on properties of foam concrete

Though foam concrete was initially envisaged as a void filling and insulation material, there have been renewed interest in its structural characteristics in view of its lighter weight, savings in material and potential for large scale utilization of wastes like fly ash. The focus of this paper is to classify literature on foam concrete in terms of constituent materials (foaming agent, cement and other fillers used), mix proportioning, production methods, fresh and hardened properties of foam concrete. Based on the review, the following research needs have been identified: (i) developing affordable foaming agent and foam generator, (ii) investigation on compatibility between foaming agent and chemical admixtures, use of lightweight coarse aggregate and reinforcement including fibers, (iii) durability studies, and (iv) factors influencing foam concrete production viz., mixing, transporting and pumping.     

Enhanced Delignification of Wheat Straw by the Combined Effect of Hydrothermal and Fungal Treatments

Delignification is the crucial step for the conversion of lignocelluloses to biofuel. In this work, wheat straw delignification was enhanced by a two-step process, comprising hydrothermal and fungal treatments. Wheat straw was exposed to hydrothermal treatment at subcritical temperatures and then subjected to fungal treatment. Lignocellulose hydrolysis rate was significantly higher during the hydrothermal treatment compared to the slower fungal delignification. However, by-products of lignin degradation via hydrothermal treatment were re-deposited on the cellulose fibers as the substrate was cooled to room temperature. It is shown that post-treatment fungi can enhance delignification by degradation of the residual lignin by-products. The effect of fungal delignification of hydrothermally treated substrate was a function of temperature of the hydrothermal process. Compared to the hydrothermal treatment, the novel combined approach, proposed in this study, resulted in two-fold higher delignification and promises to be an effective method for delignified substrate preparation for conversion to biofuel.