Hybrid system for handling premature convergence in GA – Case of grammar induction

Grammar induction (also known as grammar inference or language learning) is the process of learning grammar from training data. This paper presents hybrid genetic algorithm (GA) Tool for handling premature convergence for the case of grammar induction. The tool is developed in Java and the results are tested for the set of 20 languages. It is an effort towards introduction of a hybrid GA system where the collection of more than one type of reproduction methods is used for the grammar induction. Paper also includes the discussion on the various approaches used by author for handling the premature convergence problem in using GA.     

Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Ultrathin MoS₂ sheets and nanostructures are promising materials for electronic and optoelectronic devices as well as chemical catalysts. To expand their potential in applications, a fundamental understanding is needed of the electronic structure and carrier mobility as a function of strain. In this paper, the effect of strain on electronic properties of monolayer MoS₂ is investigated using ab initio simulations based on density functional theory. Our calculations are performed in both infinitely large two-dimensional (2D) sheets and one-dimensional (1D) nanoribbons which are theoretically cut from the sheets with semiconducting \( [\bar{1}100] \) (armchair) edges. The 2D crystal is studied under biaxial strain, uniaxial strain, and uniaxial stress conditions, while the 1D nanoribbon is studied under a uniaxial stress condition. Our results suggest that the electronic bandgap of the 2D sheet experiences a direct-indirect transition under both tensile and compressive strains. Its bandgap energy (E _g) decreases under tensile strain/stress conditions, while for an in-plane compression, E _g is initially raised by a small amount and then decreased as the strain varies from 0 to ?6 %. On the other hand, E _g at the semiconducting edges of monolayer MoS₂ nanoribbons is relatively invariant under uniaxial stretches or compressions. The effective masses of electrons at the conduction band minimum (CBM) and holes at the valence band maximum (VBM) are generally decreased as the in-plane extensions or compressions become stronger, but abrupt changes occur when CBM or VBM shifts between different k-points in the first Brillouin zone.     

A Precision Ultrasonic Phase Velocity Measurement Technique for Liquids

Present paper reports the design and developmental aspects of a new technique for ultrasonic phase velocity measurement in liquids, which is based on the studies carried out on frequency dependence of ultrasonic velocity in pure, binary and ternary liquids/mixtures. The design and developmental aspects of the experimental set up are reported along with optimisation of data acquisition software developed in LabVIEW. Finally, the developed technique is used to measure phase velocity in water (W), aqueous solution of mannitol (M), binary mixture of tertiary butyl alcohol (TBA) in water and a tertiary mixture of TBA + W + M. The results are reported within frequency bandwidth from 3 to 7 MHz. The main reason for selecting these liquids was to identify some of the liquids which can be used as reference liquids for metrological applications. Although, reporting the systematic studies to find out the reference liquid is beyond the scope of the present paper due to obvious reasons, and will be dealt separately, but the studies certainly demonstrate that the technique can successfully be used for phase velocity measurement as a function of frequency and temperature.     

Skin injuries in interventional procedures

Radiation-induced skin injuries to patients in interventional procedures have been reported since the early 1990s, but the number reported is far less than what might be occurring around the world. There is a gross lack of awareness resulting in patients suffering. A case of severe injury observed in multiple percutaneous coronary interventions for chronic total occlusion is reported in this paper. Further, the paper summarises the existing knowledge on radiation dosimetry in interventional procedures, factors involved in skin injury, guidance on detection, and avoidance and management of injury when it occurs. Information on a recently launched international anonymous reporting system of the International Atomic Energy Agency is also included.     

Electrical, optical and vibrational characteristics of nano structured yttrium barium stannous oxide synthesized through a modified combustion method

A single step combustion process for the preparation of nanoparticles of yttrium barium stannous oxide is reported in this paper. The structure, phase purity and particulate properties of the as prepared nano YBa₂SnO_5.5 powder were examined by X-ray diffraction and transmission electron microscopy. The as prepared powder obtained itself is phase pure and possess cubic structure with lattice constant 8.240 Å. The particle size of the as prepared sample from Transmission Electron Microscopy analysis is in the range of ∼15 nm. Vibrational studies carried out on the as prepared powder also confirm the cubic structure of the as prepared sample. The thermal stability of the nano particle is analyzed by thermo gravimetric and differential thermal analysis. The material is a semiconductor with excellent luminescent properties. Chemical compatibility of the sample with YBCO is analyzed. The YBCO-YBa₂SnO_5.5 composite showed T_c(0) at 92 K.     

Groundwater management and development by integrated remote sensing and geographic information systems: prospects and constraints

Groundwater is one of the most valuable natural resources, which supports human health, economic development and ecological diversity. Overexploitation and unabated pollution of this vital resource is threatening our ecosystems and even the life of future generations. With the advent of powerful personal computers and the advances in space technology, efficient techniques for land and water management have evolved of which RS (remote sensing) and GIS (geographic information system) are of great significance. These techniques have fundamentally changed our thoughts and ways to manage natural resources in general and water resources in particular. The main intent of the present paper is to highlight RS and GIS technologies and to present a comprehensive review on their applications to groundwater hydrology. A detailed survey of literature revealed six major areas of RS and GIS applications in groundwater hydrology: (i) exploration and assessment of groundwater resources, (ii) selection of artificial recharge sites, (iii) GIS-based subsurface flow and pollution modeling, (iv) groundwater-pollution hazard assessment and protection planning, (v) estimation of natural recharge distribution, and (vi) hydrogeologic data analysis and process monitoring. Although the use of these techniques in groundwater studies has rapidly increased since early nineties, the success rate is very limited and most applications are still in their infancy. Based on this review, salient areas in need of further research and development are discussed, together with the constraints for RS and GIS applications in developing nations. More and more RS- and GIS-based groundwater studies are recommended to be carried out in conjunction with field investigations to effectively exploit the expanding potential of RS and GIS technologies, which will perfect and standardize current applications as well as evolve new approaches and applications. It is concluded that both the RS and GIS technologies have great potential to revolutionize the monitoring and management of vital groundwater resources in the future, though some challenges are daunting before hydrogeologists/hydrologists.     

Characteristics of holding, patterns of play, and social behaviors between parents and infants in New Delhi, India.

Characteristics of holding, play, and social behaviors between 54 mothers and fathers and their 1-year-old infants were observed within the context of their extended families in New Delhi, India. Mothers picked up and held infants more than did fathers, and were more likely to feed and comfort them and to invest more time feeding and displaying affection to them than were fathers. When parents held infants they were more likely to display affection than to feed, comfort, or play with them. Fathers engaged in more rough play than did mothers, and mothers engaged in more peek-a-boo than did fathers. Mothers and fathers treated boys and girls quite similarly. Infants smiled at, vocalized to, and followed mothers more than they did fathers. Parents were generally preferred over relatives as social partners. The data point to the cultural specificity of certain parent–child activities. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The role of grain size and selected microstructural parameters in strengthening fully lamellar TiAl alloys

More than 5 years ago, wrought processing was first used to produce fully lamellar (FL) microstructures in TiAl alloys having grain sizes less than ≈400 μm. These alloys exhibit an improvement in overall balance of properties, especially at high temperatures. More recently, such microstructural forms led to exceptional yield strengths (500 to 1000 MPa at low temperatures) while maintaining attractive high-temperature properties. The improvements appeared to be related to an unusually high apparent sensitivity of strength to grain size. Studies reported an apparent value for the slope of the Hall-Petch (HP) plot approaching 5 MPa√m for FL gamma alloys, while that for single-phase or duplex microstructures is near unity. The present investigations examine the slope of the HP plot for FL microstructures, paying particular attention to the lamellar microstructural variables. Results show that the α ₂ lamellar thickness and spacing and the γ lamellar thickness can vary over more than two orders of magnitude with typical process methods. These spacings influence the value of k _y in the HP (grain size) relationship. Since they often change concomitantly with grain size in processing, they can give rise to a large scatter in the HP plot. The investigations also examine the flow behavior, glide barriers, and slip multiplicity for polysynthetically twinned (PST) crystals (the single-grain analogue of FL material), and then map this behavior into an explanation of the yield behavior of high-strength FL gamma alloys. This article is based on a presentation made in the symposium “Fundamentals of Gamma Titanium Aluminides,” presented at the TMS Annual Meeting, February 10–12, 1997, Orlando, Florida, under the auspices of the ASM/MSD Flow & Fracture and Phase Transformations Committees.