227 research outputs found

    A Multi-objective Perspective for Operator Scheduling using Fine-grained DVS Architecture

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    The stringent power budget of fine grained power managed digital integrated circuits have driven chip designers to optimize power at the cost of area and delay, which were the traditional cost criteria for circuit optimization. The emerging scenario motivates us to revisit the classical operator scheduling problem under the availability of DVFS enabled functional units that can trade-off cycles with power. We study the design space defined due to this trade-off and present a branch-and-bound(B/B) algorithm to explore this state space and report the pareto-optimal front with respect to area and power. The scheduling also aims at maximum resource sharing and is able to attain sufficient area and power gains for complex benchmarks when timing constraints are relaxed by sufficient amount. Experimental results show that the algorithm that operates without any user constraint(area/power) is able to solve the problem for most available benchmarks, and the use of power budget or area budget constraints leads to significant performance gain.Comment: 18 pages, 6 figures, International journal of VLSI design & Communication Systems (VLSICS

    A Cultural Algorithm for the Two Variable Integer Programming Problem

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    A specific implementation of cultural algorithm is presented here for solving the following two variable integer programming problem with n constraints: Maximize or Minimizeare signed integers. A cultural algorithm consists of a population component almost identical to that of the genetic algorithm and, in addition, a knowledge component called the belief space. As the integer programming problem is a constrained optimization problem, the constraints including nonnegativity and integer restrictions are availed as the knowledge component and used to build the belief space

    Domain Aligned Prefix Averaging for Domain Generalization in Abstractive Summarization

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    Domain generalization is hitherto an underexplored area applied in abstractive summarization. Moreover, most existing works on domain generalization have sophisticated training algorithms. In this paper, we propose a lightweight, weight averaging based, Domain Aligned Prefix Averaging approach to domain generalization for abstractive summarization. Given a number of source domains, our method first trains a prefix for each one of them. These source prefixes generate summaries for a small number of target domain documents. The similarity of the generated summaries to their corresponding documents is used for calculating weights required to average source prefixes. In DAPA, prefix tuning allows for lightweight finetuning, and weight averaging allows for the computationally efficient addition of new source domains. When evaluated on four diverse summarization domains, DAPA shows comparable or better performance against the baselines, demonstrating the effectiveness of its prefix averaging scheme.Comment: 13 pages, Accepted to ACL 2023 Finding

    Processing, microstructure and high strain rate behaviour of Ti-6Al-4V Alloy produced from a blended mixture using powder compact extrusion

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    Powder compact extrusion (PCE) is an innovative way of processing titanium and titanium alloys to produce good-quality material with a wide range of compositions, microstructures and mechanical properties. This paper explores PCE processing of Ti-6Al-4V alloy prepared from a blended powder mixture, containing elemental hydride-dehydride (HDH) titanium powder and master alloy (60Al-40V) powder. The warm pressed compacts of blended powders were sintered using a vacuum sintering furnace prior to β extrusion. The resulting material was used to measure the performance under high strain rate and tri-axial stress state using Charpy v-notch testing. A comparison was made of the microstructure after vacuum sintering and hot extrusion in addition to oxygen measurements to determine the degree of oxygen pickup during each processing stage. A comprehensive study of fracture surfaces in selected samples was carried out using optical microscopy and scanning electron microscopy. Based on the results, it is clear that certain samples picked up varying amounts of interstitial impurities during processing and as a consequence a significant number of micro-cracks were observed in lamellar type microstructures. The oxygen content of all as-extruded samples was between 0.34-0.44 wt.% with resultant impact toughness in the range of 10-14 J. The best impact toughness attained for the lowest oxygen as-extruded rods was 20% lower than the literature values for wrought material. In terms of fracture behaviour, ductile dimples, cleavage facets and cracks passing through lamellar structures were observed in all samples. However, the quantity of these fracture features varied significantly in each sample

    EVALUATION OF THE EFFICACY OF PRANAYAMA ON THE LUNGS

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    Yoga is a science which has been practised in India from over thousands of years. Besides the spiritual achievements, the practice of yoga is accompanied by a number of beneficial physiological effects in the body. Yoga and health goes hand in hand. Yoga calms and relaxes the mind and it strengthens and tunes the body and brings them into harmony with each another. Pranayama is an art of controlling the life force of breath [1]. It produces many systemic psycho-physical effects in the body, besides its specific effects on the respiratory functions. This study is designed to study the effects of pranayama (12 weeks) on the pulmonary function parameters. It is one of the best lifestyle modifications which have ever been devised in the history of mankind. There are many classical paths which have been described to reach the ultimate goal of healthy life. It is an ancient yoga technique, a spiritual and physical practice which integrates the mind and body. Pranayama is a type of yogic practice which produces many systemic psycho-physical effects in the body, besides its specific effects on the respiratory functions. So, it has become a standard fare at health clubs and community recreation programmes.Pulmonary function tests (PFTs) are simple screening procedures which are performed by using a standardized equipment (spirometer) to measure the lung function. This test provides useful information about the minimum levels of the lung function. The breath holding time measures the level of the threshold of the respiratory center to the partial pressure of the carbon dioxide (Pco2) level.Pulmonary function tests have been studied in yoga and pranayama practitioners. They have shown that the regular practice of these pranayama techniques have proved to be beneficial for the human body. Pranayama has a favourable influence and it causes a marked improvement in the lung functions. This study is designed to study the effects of pranayama (12 weeks) on the pulmonary function parameters.In these clinical trial 60 patients of mild to moderate hypertensive patients were randomly selected and divided in to two groups. In each group 30 patients had taken. In Group A Pranayam had been given to the 30 patients of mild to moderate hypertensive patients and In Group B only placebo drug Prana had given to the 30 patients mild to moderate hypertensive patients. In all these two groups, group A was found as the most benefited because it showed significant changes in symptoms and Biochemistry investigations. Whereas in Group B (Placebo group) showed insignificant changes in symptoms as well as in Biochemistry investigations.    Key words-For Yoga- Pranayama, Yoga, Pulmonary Function Parameters FVC FEV1 FEF (25-75percent), and BHT For Hypertension-Vyan vikriti, vyan bala, Raktavritta vata, Raktagata vata, Dhamani Pratichaya, Siragata vata, Rasabhara, Dhamani Prapurnata, Vyanavrita vata etc. Â

    Effect of heat treatments on microstructure and mechanical properties of low-cost Ti-6Al-4V alloy produced by thermo-mechanical powder consolidation route

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    This paper investigates the level of properties enhancement achievable by heat-treating Ti-6Al-4V alloy produced from a blended powder mixture using a thermomechanical powder consolidation route involving warm uniaxial pressing and vacuum sintering followed by extrusion at super transus temperature (1150°C). The as-extruded material with a higher oxygen content of 0.55 wt.% was subjected to two different sub-transus annealing treatments: HT-A: 955°C/1h furnace cooling and HT-B: 925°C/4h-cooling @ 50°C/h to 760°C-FCfurnace cooling. Room temperature Charpy v-notch impact toughness tests and tensile tests were performed to ascertain the effect of microstructural changes during post-extrusion annealing treatments. After impact tests, analysis of microstructures and fracture surfaces of samples after impact tests were was carried out using optical microscopy and scanning electron microscopy. The as-extruded material displayed mean impact toughness of 4 J along with a yield strength of 956 MPa, an ultimate tensile strength of 22 1150 MPa, and an elongation to fracture of 2.4%. The annealing treatments gave a noticeable enhancement in the impact toughness (average values 5.3-6.3 J obtained) while maintaining a yield strength and ultimate tensile strength level of about 992 MPa and 1164-1181 MPa, respectively. Additionally, the level of change in ductility was limited for each sub-transus annealing treatment, and HT-A has given only a 30% increase compared to as-extruded material

    Effect of minor titanium addition on copper/diamond composites prepared by hot forging

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    Copper/diamond composites have great potential to lead the next generation of advanced heat sink materials for use in high-power electronic devices and high-density integrated circuits because of their potential excellent properties of high thermal conductivity and close thermal expansion to the chip materials (e.g., Si, InP, GaAs). However, the poor wettability between copper and diamond presents a challenge for synthesizing copper/diamond composites with effective metallurgical bonding and satisfied thermal performance. In this article, copper/diamond composites were successfully prepared by hot forging of elemental copper and artificial diamond powders with small amounts (0 vol.%, 3 vol.% and 5 vol.%) of titanium additives. Microstructure observation and mechanical tests showed that adding minor titanium additions in the copper/diamond composite resulted in fewer cracks in the composites’ microstructure and significantly improved the bonding between the copper and diamond. The strongest bonding strength was achieved for the copper/diamond composite with 3 vol.% titanium addition, and the possible reasons were discussed
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