Combined gradient‐stochastic optimization with negative circular masks for large deformation topologies

Topology optimization of large deformation two‐dimensional continua is presented using a combined gradient‐stochastic search with negative circular masks. The possibility of generating perfect black and white topologies is explored while attaining the efficiency of first‐order and second‐order search algorithms. The design region is modeled with honeycomb tessellation to thwart the known connectivity singularities such as the checkerboards and point flexures. Mask shrinkage is incorporated for ease in density transition between gradient and stochastic steps. Notches at continuum boundaries are moderated through multiple use of a simple boundary smoothing method. A neo‐Hookean elasticity model is employed to simulate the material nonlinearities in large displacement continua. With examples on stiff beams and large deformation compliant mechanisms, it is illustrated that perfectly binary, connected and smooth topologies can be obtained within a few hundred design evaluations.Copyright © 2012 John Wiley & Sons, Ltd.     

Food adulteration: Sources,health risks,and detection methods

Adulteration in food has been a concern since the beginning of civilization, as it not only decreases the quality of food products but also results in a number of ill effects on health. Authentic testing of food and adulterant detection of various food products is required for value assessment and to assure consumer protection against fraudulent activities. Through this review we intend to compile different types of adulterations made in different food items, the health risks imposed by these adulterants and detection methods available for them. Concerns about food safety and regulation have ensured the development of various techniques like physical, biochemical/immunological and molecular techniques, for adulterant detection in food. Molecular methods are more preferable when it comes to detection of biological adulterants in food, although physical and biochemical techniques are preferable for detection of other adulterants in food.     

Intelligent agents meet the semantic Web in smart spaces

A new smart meeting room system called EasyMeeting explores the use of multi-agent systems, Semantic Web ontologies, reasoning, and declarative policies for security and privacy. Building on an earlier pervasive computing system, EasyMeeting provides relevant services and information to meeting participants based on their situational needs. The system also exploits the context-aware support provided by the Context Broker Architecture (Cobra). Cobra's intelligent broker agent maintains a shared context model for all computing entities in the space and enforces user-defined privacy policies.     

Integrating service discovery with routing and session management for ad-hoc networks

In this paper, we propose GSR: a new routing and session management protocol for ad-hoc networks as an integral part of a service discovery infrastructure. Traditional approaches place routing at a layer below service discovery. While this distinction is appropriate for wired networked services, we argue that in ad-hoc networks this layering is not as meaningful and show that integrating routing with discovery infrastructure increases system efficiency. Central to our protocol is the idea of reusing the path created by the combination of a service discovery request and a service advertisement for data transmission. This precludes the need to use separate routing and discovery protocols. GSR also combines transport layer features and provides end-to-end session management that detects disconnections, link and node failures and enables service-centric session redirection to handle failures. This enables GSR to accommodate service-centric routing apart from the traditional node-centric routing. We compare GSR with AODV in terms of packet delivery ratio, response time and average number of hops traveled by service requests as well as data. GSR achieves better packet delivery ratio with a minor increase of the average packet delivery delay.     

Trajectory Generation Using GA for an 8 DOF Biped Robot with Deformation at the Sole of the Foot

In biped robot dynamics, the foot is generally considered rigid. However, in practical cases, there will be a layer of rubber on the sole to act as a shock absorber. Such electrodynamic contact has been studied in the case of industrial robots, but the experience with biped robots is rare. The goal of this paper is to device a trajectory generation method using a genetic algorithm (GA) for an 8 DOF robot that can walk on flat terrain and climb stairs with deformation at the sole. The proposed method uses splines to model each joint angle and needs a single GA layer, which makes it faster and simpler than earlier models. The method incorporates the dynamics of an actual 8 DOF robot to find the most energy optimal gait. A simple control method is proposed that corrects the computed angle required to follow ZMP incorporating the deformation of the sole. Using the control method the computed angle is first corrected and then the trajectory optimized. Energy consumed in three cases were compared: walk on flat ground with no sole deformation, walk with uncorrected deformed soft sole and walk with deformed soft sole with correction of deformation. It is found that the least energy was consumed in the case of soft sole with correction for deformation. This proves the need for deformation correction of soft sole and the usefulness of our proposed method.     

Nonradiative resonant excitation transfer from nanocrystal quantum dots to adjacent quantum channels

Evidence is provided for nonradiative resonant energy transfer (NRET) from excitons in nanocrystal quantum dots (NCQDs) to the confined states of an adjacent quantum well (QW) at low excitation power and rate competitive with the quantum dot radiative decay. This indicates that NRET in optimized NCQD-QW/nanowire systems may provide a solar energy conversion approach with a viable tradeoff with the bottlenecks of charge carrier generation and/or transport to/in electrodes faced by excitonic solar cells.     

One-Pot Synthesis of Magnetite-ZnO Nanocomposite and Its Photocatalytic Activity

Topics in Catalysis - Tri-octyl-amine is known for its potential to assist fabrication of metal and metal oxides nanoparticles. In this work elucidate the synthesis of magnetite-ZnO magnetic nano...     

Investigation and modeling of the structure of texting language

Language usage over computer mediated discourses, such as chats, emails and SMS texts, significantly differs from the standard form of the language and is referred to as texting language (TL). The presence of intentional misspellings significantly decrease the accuracy of existing spell checking techniques for TL words. In this work, we formally investigate the nature and type of compressions used in SMS texts, and develop a Hidden Markov Model based word-model for TL. The model parameters have been estimated through standard machine learning techniques from a word-aligned SMS and standard English parallel corpus. The accuracy of the model in correcting TL words is 57.7%, which is almost a threefold improvement over the performance of Aspell. The use of simple bigram language model results in a 35% reduction of the relative word level error rates.