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Search Results: 1 - 10 of 5201 matches for " Roy Danchick "
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A Continuous Dynamical Systems Approach to Gauss-Newton Minimization  [PDF]
Roy Danchick
Open Access Library Journal (OALib Journal) , 2014, DOI: 10.4236/oalib.1101028
Abstract: In this paper we show how the iterative Gauss-Newton method for minimizing a function can be reformulated as a solution to a continuous, autonomous dynamical system. We investigate the properties of the solutions to a one-parameter ODE initial value problem that involves the gradient and Hessian of the function. The equation incorporates an eigenvalue shift conditioner, which is a non-negative continuous function of the state. It enforces positive definiteness on a modified Hessian. Assuming the existence of a unique global minimum, the existence of a bounded connected sub-level set of the function and that the Hessian is non-zero in the interior of this set, our main results are: 1) existence of local solutions to the ODE initial value problem; 2) construction of a global solution by recursive extension of local solutions; 3) convergence of the global solution to the minimizing state for all initial values contained in the interior of the bounded level set; 4) eventual exact exponential decay of the gradient magnitude independent of the particular function and number of its variables. The results of a numerical experiment on the Rosenbrock Banana using a constant step-size 4th order Runge-Kutta method are presented and we point toward the direction of future research.
A New Approach to Telescope Fourier Optics  [PDF]
Roy Danchick
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105856
Abstract:
In this paper we take a new approach to solving the Ray-leigh-Sommerfeld-Smythe equation for a telescope’s optical impulse re-sponse to a monochromatic point source spherical wave radiating outward from the origin in the object plane. Two cases are covered: 1) the point source at the origin in the telescope’s near-field object plane; 2) the point source at the origin in the far-field object plane as is the case with satellite infrared sensors when the distance between the telescope and the point source is very much greater than the telescope’s circular aperture diameter. With only the assumption of a thin circular aperture we 1) derive a general solution that erases the distinction among the three classically defined zones of the optical axis: Near, Fresnel, and Fraunhofer; 2) reduce the computational complexity down from two-dimensional to one-dimensional Fourier transform integrals and; 3) identify Filon quadrature as the numerical method of choice for accurately and efficiently approximating the values of these integrals and; 4) provide a computational example.
Probabilistic Prediction for Earthquake in Bangladesh: Just How Big Does the Earthquake Have to Be Next Years?  [PDF]
Shongkour Roy
Open Journal of Earthquake Research (OJER) , 2014, DOI: 10.4236/ojer.2014.32011
Abstract: Earthquakes are more deadly than any other form of natural hazard. Because of this, scientists have been searching for accurate ways to predict earthquakes so that lives can be saved. Statistical analysis is useful methods of predicting earthquakes. They provide additional insights to the seismic hazard. In this work, the statistical analysis has been described through the study of “Region of Bangladesh”. A sample result from the statistical analysis which gives intermediate term prediction of earthquakes is given. At the end of the study, the prediction of near future earth-quakes is also investigated through the pictorial and tabular behaviors.
The “Glocal” Dynamics of Construction Labor and Digital Architecture: Preston Scott Cohen’s Addition to the Tel Aviv Museum as Case Study  [PDF]
Roy Kozlovsky
Journal of Building Construction and Planning Research (JBCPR) , 2015, DOI: 10.4236/jbcpr.2015.32009
Abstract: Globalization and technological change are transforming the ways in which buildings are being designed and built. An overlooked aspect of this development is its impact on construction labor, and the significance of labor for assessing the work of architecture. The paper draws upon the sociological concept of the “glocal” to analyse the construction site as the product of the tension between global and local conditions of architectural production and consumption. The construction of Preston Scott Cohen’s 2010 Tel Aviv Museum Addition serves as its case study for theorizing the “glocal” dynamics of digital architecture, building technology and construction labor. This methodological approach highlights the role of migrant guest workers and technological transfer in contemporary construction culture. To realize with precision the complex design under local constraints, the contractor developed a hybrid work process that interspersed labor saving automated manufacturing techniques with artisanal, skilled construction work. In addition, workers and contractors exercised a high level of control over the pace and method of construction, and devised building solutions which improved upon the architect’s design. In conclusion, the paper argues that construction activity differs from broader trends in manufacturing due to the self-reflexivity of architectural design to its condition of production, but that at the same time, this critical capacity is enabled by the globalization of construction labor.
Use of Medicinal Plant and Its Vulnerability Due to Climate Change in Northern Part of Bangladesh  [PDF]
Sadhan Kumar Roy, Dipak Kumar Roy
American Journal of Plant Sciences (AJPS) , 2016, DOI: 10.4236/ajps.2016.713166
Abstract: Medicinal plants are playing an important role to human livelihood. Bangladesh is well recognized of medicinal plants wealth as unique and globally rich. The studies demonstrate about the value of traditional systems of medicine as economically useful plants and possible effects of climate change on medicinal plants. It is true that climate change is causing noticeable effects on life cycles and distribution of the plant species. However, climate change effects on medicinal plants are widely unclear in Bangladesh. At present, a huge number of populations in Bangladesh are directly dependent on the healthcare treatment by medicinal plants that is why it is an emerging concern in Bangladesh. It is a crying need to improve our understanding the effects on medicinal plants by various researches is stressed in the present article. To know the present condition of medicinal plants and effects of climate change on medicinal plants in northern part of Bangladesh an attempt is being taken here. The study also added the optimum use of medicinal plants and their conservation in northern part of Bangladesh.
Adoption and Use of Household Microgeneration Heat Technologies  [PDF]
Sally Caird, Robin Roy
Low Carbon Economy (LCE) , 2010, DOI: 10.4236/lce.2010.12008
Abstract: The development and rapid household adoption of smallscale, low and zero carbon microgeneration technologies are key elements of UK and EU strategies to meet the challenge of climate change. Microgeneration heat technologies, including solar thermal hot water, heat pumps and biomass heating systems, have an especially important role in reducing the carbon emissions from buildings. But despite government policies to promote microgeneration, adoption by UK householders is very slow. Surveys by the Open University and Energy Saving Trust examined why over 900 UK householders decided to adopt these technologies and why many do not. These surveys describe the niche market for microgeneration heat as largely confined to environmentally concerned, older, middleclass householders, mainly living in larger properties off the mains gas network. Although these pioneer adopters are generally highly satisfied, for microgeneration heat to expand beyond its market niche, several issues need to be addressed, including: price reductions and subsidies? independent information on the suitability, performance, payback and effective use of equipment? ‘one- stop’ support from consideration to operation? improved system compatibility with smaller properties and existing buildings and heating systems? and more userfriendly and informative controls.
Performance Evaluation of Signal Strength Based Handover Algorithms  [PDF]
Sanjay Dhar ROY
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.27075
Abstract: Performance evaluation of handover algorithms has been studied for mobile cellular network. Effects of averaging, hysteresis margin and shadow fading are investigated for different handoff algorithms. Probability of outage, handover delay and average number of handovers are considered as performance metrics. Different handover algorithms considered here are based on relative signal strength with hysteresis, relative signal strength with hysteresis and threshold, absolute signal strength and combined relative and absolute signal strength. Both analytical and simulation methods have been used in this paper. This study is important as performance analyses of cellular system, in presence of handoff, will be important for future generation wireless networks, for example, WiMAX, UMTS.
Modified Shuffled Frog Leaping Algorithm for Solving Economic Load Dispatch Problem  [PDF]
Priyanka Roy, A. Chakrabarti
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.34068
Abstract: In the recent restructured power system scenario and complex market strategy, operation at absolute minimum cost is no longer the only criterion for dispatching electric power. The economic load dispatch (ELD) problem which accounts for minimization of both generation cost and power loss is itself a multiple conflicting objective function problem. In this paper, a modified shuffled frog-leaping algorithm (MSFLA), which is an improved version of memetic algorithm, is proposed for solving the ELD problem. It is a relatively new evolutionary method where local search is applied during the evolutionary cycle. The idea of memetic algorithm comes from memes, which unlike genes can adapt themselves. The performance of MSFLA has been shown more efficient than traditional evolutionary algorithms for such type of ELD problem. The application and validity of the proposed algorithm are demonstrated for IEEE 30 bus test system as well as a practical power network of 203 bus 264 lines 23 machines system.
Identification and Characterisation of a Bacterial Isolate Capable of Growth on Trichloroethylene as the Sole Carbon Source  [PDF]
Piyali Mukherjee, Pranab Roy
Advances in Microbiology (AiM) , 2012, DOI: 10.4236/aim.2012.23034
Abstract: The aim of this research work was to isolate microbes from soil, to investigate their potential use as effective bioremediation tools for trichloroethylene—a potent environmental pollutant. The isolate showing good growth in presence of TCE was named PM102. Microbiological characterisation of the PM102 isolate showed that it was a gram negative rod. Detailed structure was revealed by scanning electron microscopy. pH and temperature optima, salt tolerance and optimum TCE concentration for growth of PM102 were determined. The ability of this bacterium to degrade TCE was studied in acidic and neutral pH by biochemical test and chloride release. Five TCE inducible bands were detected in the protein profile of the isolate as studied by SDS PAGE. A major TCE inducible band of 51.61 kDa was excised from the gel and injected into rabbit to raise specific antibody. The bacterium was identified as Stenotrophomonas maltophilia PM102 by 16S rDNA amplification and sequencing. The 16S rRNA gene sequence has been deposited in the NCBI GenBank with accession number JQ797560. This genus has not been described previously as being capable of TCE degradation. We report for the first time a Stenotrophomonas sp. that grows on TCE as the sole carbon source.
A Simple Statistical Estimation of One’s Performance in an MCQ Examination, Based Upon Mock Test Results, Using Binomial Distribution of Probability  [PDF]
Sudipto Roy, Priyadarshi Majumdar
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.24057
Abstract: A simple statistical model is proposed regarding the estimation of one’s overall performance in an MCQ examination along with the calculation of probability of obtaining a certain percentage of marks in the same. Using the data obtained from the results of a sufficiently large number of mock examinations, conducted prior to the main examination, certain parameters quantifying one’s knowledge or preparation for the examination has been calculated. Based on those parameters, the probability of obtaining a certain percentage of marks has been computed using the theory of binomial probability distribution. The dependence of this probability function on various parameters has been depicted graphically. A parameter, called the performance index, has been defined in terms of the expectation value and standard deviation of marks computed from probability distribution. Using this parameter, a new parameter called the relative performance index has been defined. This index estimates one’s performance with respect to the best possible performance. The variation of relative performance index with respect to the preparation index has been shown graphically for different parameter values quantifying various aspects regarding the examination and the examinee.
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