Adaptive case-based reasoning using retention and forgetting strategies

Case-based reasoning systems need to maintain their case base in order to avoid performance degradation. Degradation mainly results from memory swamping or exposure to harmful experiences and so, it becomes vital to keep a compact, competent case base. This paper proposes an adaptive case-based reasoning model that develops the case base during the reasoning cycle by adding and removing cases. The rationale behind this approach is that a case base should develop over time in the same way that a human being evolves her overall knowledge: by incorporating new useful experiences and forgetting invaluable ones. Accordingly, our adaptive case-based reasoning model evolves the case base by using a measure of “case goodness” in different retention and forgetting strategies. This paper presents empirical studies of how the combination of this new goodness measure and our adaptive model improves three different performance measures: classification accuracy, efficiency and case base size.     

Superplasticity and associated activation energy in Ti-3Al-8V-6Cr-4Mo-4Zr Alloy

The high temperature deformation characteristics of a commercial β -titanium alloy Ti-3Al-8V-6Cr-4Mo-4Zr have been studied in the temperature range 830–925∘C. The alloy exhibited superplasticity in a narrow temperature and strain rate range i.e. 850–865∘C and 5× 10^{− 5}–3× 10^{− 3} s^{− 1} respectively, with a maximum elongation of 634% at 855∘C. The superplastic behaviour in the alloy is considered to arise as a result of subgrain formation at the higher strain rates (region III) which enhances diffusional creep at lower strain rates (region II). The activation energy values for regions II and III were found to be close to the lower of the two activation energy values (129.2 KJ/mole) proposed to describe self diffusion in β -phase suggesting that the rate controlling mechanism during high temperature deformation of the alloy was that for lattice diffusion.     

Development of environmental standards for combined desalination/power generating stations in the Arabian Gulf region

Environmental effects associated with desalination/power generation are classified into intake and discharge components. The intake component consists of entrainment and impingement problems while the discharge component comprises chemical and physical problems associated with the receiving waterbody. Each component is discussed relative to marine communities in the receiving waterbody and a methodology is presented for establishing an environmental managenent policy which will protect these communities.     

Fabrication of crystalline articles of aromatic polycarbonate by hot powder‐compaction

Polycarbonate is well known for forming amorphous, transparent, and exceptionally tough articles by conventional methods such as injection molding and extrusion. It is not possible to extrude polycarbonate from the melt into crystalline, shaped articles. A novel method to fabricate crystalline polycarbonate articles from acetone‐crystallized powder was devised. The method was adapted from powder metallurgy and it involved compacting acetone‐crystallized polycarbonate powder above the glass transition temperature (T_g) and below the melting peak temperature (T_m). The hot powder‐compaction process yielded shaped articles, which retained the crystallinity of the original polycarbonate powder. Although the crystallinity of the powder and the articles was less than 20%, surprisingly the articles were non‐sticking above the T_g and so could be released from the mold at the compaction temperature. Furthermore, the crystalline polycarbonate articles had a Vicat softening temperature above 180°C, excellent shape and dimension retention above T_g, increased hardness, as well as resistance to acetone and other solvents. That is, the properties were different from those of conventional amorphous polycarbonate articles. POLYM. ENG. SCI., 57:581–590, 2017. © 2016 Society of Plastics Engineers     

Identification of preferred combination of factors in manufacturing bioepoxy/clay nanocomposites

The current study aims to identify the preferred combination of factors for manufacturing bioepoxy/clay nanocomposites based on epoxidised soybean oil (ESO), including material formulation and manufacturing parameters for maximising tensile strengths of nanocomposites according to Taguchi design of experiments (DoEs). A Taguchi mixed-level DoEs with an L ₁₆ orthogonal array was selected. The response was set to achieve the maximum tensile strengths of nanocomposites with a preferred combination of factors determined by the Pareto analysis of variance (ANOVA). The associated results revealed that the ESO content was found to be the most significant factor with a contribution percentage of 66.63% amongst nine factors investigated. This result was followed by two less significant factors, namely mechanical mixing speed and clay content with contribution percentages of 19.09 and 7.01%, respectively. However, other factors of clay type, curing agent type, mechanical mixing temperature and time, as well as sonication frequency and time, were categorised as non-significant factors from the manufacturing and economical point of view. A confirmation test was conducted based on the preferred combination of factors showing good agreement with statistically predicted results.     

Adhesion inhibition of F1C-fimbriated Escherichia coli and Pseudomonas aeruginosa PAK and PAO by multivalent carbohydrate ligands

In order to evaluate their inhibition of bacterial adhesion, the carbohydrate sequences GalNAcbeta1-->4Gal and GalNAcbeta1-->4Galbeta1-->4Glc were synthesized. The disaccharide was conjugated to dendrons based on the 3,5-di-(2-aminoethoxy)-benzoic acid branching unit to yield di- and tetravalent versions of these compounds. A divalent compound was also prepared that had significantly longer spacer arms. Relevant monovalent compounds were prepared for comparison. Their anti-adhesion properties against F1C-fimbriated uropathogenic Escherichia coli were evaluated in an ELISA-type assay by using a recombinant strain and also by using Pseudomonas aeruginosa strains PAO and PAK. Adhesion inhibition was observed in all cases, and multivalency effects of up to one order of magnitude were observed. The combination of spacer and multivalency effects led to a 38-fold increase in the potency of a divalent inhibitor with long spacer arms towards the PAO strain when compared with the free carbohydrate.     

Backward walking simulation of humans using optimization

The objective of this study is to formulate, simulate and study the backward walking motion of a full-body skeletal digital human model using an optimization approach. Predictive dynamics is used to simulate the task in which joint angle profiles are treated as primary unknowns in the formulation. The joint torques are treated as dependent variables that are evaluated directly from the equations of motion. For the performance measure, the normalized dynamic effort represented by the integral of the squares of all the normalized joint torques is minimized subject to the associated physical constraints. Backward walking at different speeds is simulated and analyzed. The backward walking is validated with motion capture data and the available data in the literature. The results of the backward walking motion are compared to those of the forward walking motion in order to study the differences between the two walking patterns. It is seen that the joint torque profiles for hip and knee of backward walk are quite similar to those of forward walk with reverse sequence, but with different time duration of flexion and extension activations. These findings can impact many fields, such as improvement of human performance, rehabilitation from injuries, and others.     

Generating recommendations for consensus negotiation in group personalization services

There are increasingly many personalization services in ubiquitous computing environments that involve a group of users rather than individuals. Ubiquitous commerce is one example of these environments. Ubiquitous commerce research is highly related to recommender systems that have the ability to provide even the most tentative shoppers with compelling and timely item suggestions. When the recommendations are made for a group of users, new challenges and issues arise to provide compelling item suggestions. One of the challenges a group recommender system must cope with is the potentially conflicting preferences of multiple users when selecting items for recommendation. In this paper, we focus on how individual user models can be aggregated to reach a consensus on recommendations. We describe and evaluate nine different consensus strategies and analyze them to highlight the benefits of group recommendation using live-user preference data. Moreover, we show that the performance is significantly different among strategies.     

Pre-Crystallization Criteria and Triple Crystallization Kinetic Parameters of Amorphous–Crystalline Phase Transition of As40S45Se15 Alloy

Journal of Inorganic and Organometallic Polymers and Materials - This framework focuses mainly on a detailed study of the pre-crystallization criteria that characterize the As40S45Se15 glassy alloy...     

Advanced extraction techniques for Berberis species phytochemicals: A review

Berberis species are known for their functional and nutraceutical properties. For example, different Berberis species have shown a wide range of pharmacological activities and they have been used in food industries as additives, preservatives and antioxidants. The functional property of any herb is influenced by many factors including the extraction process of its active components. Consequently, new extraction methodologies have been investigated to increase the efficiency of extracting bioactive compounds. In this review, we examine all the recent extraction techniques and advanced technologies that have been applied for the extraction of phytochemicals from different Berberis species. The five following techniques have been included for this purpose: ultrasound-, microwave-, pulsed electric field-assisted, supercritical carbon dioxide and subcritical water extraction. These techniques have been used to extract phenolics, flavonoids, anthocyanins and berberine from different parts of various Berberis species which include B. vulgaris, B. jaeschkeana, B. aristata, B. integerrima, B. dasystachya and B. koreana. Microwave-assisted extraction (MAE) has been well studied, optimised and evaluated. Yet, the present research considering other techniques are limited, and require further investigation and optimisation. In addition, the application of green solvents such as natural deep eutectic solvents could be considered in further developing MAE.