992 research outputs found

    Preparation of some azo compounds by diazotization and coupling of 2- amino -5 – thiol -1,3,4- thiadizaole

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    2- amino -5- thiol-1,3,4- thiadiazole (S1) was prepared by cyclic locking of thiosemicarbazide in the presence of anhydrous sodium carbonate and CS2. diazotization of (S1) compound gave diazonium salt (S2) that reacts with different activated aromatic compounds to get the following azo compounds ,2 [(4- aminophenyl) diazenyl ] 1,3,4- thiazdiazole-5- thiol (S3) ,2-[4-amino- 1-naphthyl diazenyl] -1,3,4 – thiazdiazole-5-thiol (S4) , 3-amino-4-[(5- mercapto -1,3,4- thiadiazole -2-yl) diazenyl ] phenol(S5) ,1-[(5-mercapto-1,3,4-thiadiazole-2-yl) diazenyl] -2-naphthol (S6) , 5-{[4-(dimethylamino) phenyl] diazenyl}-1,3,4-thiadiazole-2- thiol(S7) ,5-{[4-(diethylamino) phenyl] diazenyl}-1,3,4- thiadiazole-2- thiol(S8) ,2- amino-5-[(5-mercapto-1,3,4-thiadiazole-2-yl) diazenyl] phenol(S9) . All the prepared azo compounds have been characterized and identified through the study of their some physical, chemical and spectrometrical (U.V.I.R) properties

    Synthesis of some Schiff's bases derivatives from aminoazo compounds

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    Reaction of,2- [( 4- amio phenyl ) diazenyl] 1,3,4- thiadiazole -5- thiol (S1) with p- chlorobenzeldehyde,3,4 – dimethoxy benzaldehyde and pyrrol-2- carbonxaldehyde gave -5- [{4-(4-chlorobenzylidene amino) phenyl} diezenyl]-1,3,4- thiadiazole-2- thiol (S2),5-[{ 4-[(3,4- dimethoxybenzyldene )amino phenyl ] diazenyl)-1,3,4- thiadiazole-2-thiol,(S3) and -5- [4-(1,H – pyrrol -2- yl- methylene)amino phenyl] diazenyl)-1,3,4- thiadiazole-2- thiol (S4) respectively as schiff's bases compounds. On the same route-2-[(4-amino-1- naphthyl ) diazenyl] -1,3,4- thiadiazole -5- thiol (S5) reacts with –p- chloro benzaldehyde and –m- nitrobenzaldehyde to give the follwing schiff's bases -5-[{ 4-(4- chloro benzylidene ) amino -1- naphthyl} diazenyl] -1,3,4- thiadiazole -2- thiol (S6) and -5- ({ 4- [3- nitrobenzylidene) amino] -1- naphthyl({ diazenyl) -1,3,4 – thiadiazole-2- thiol (S7). Sn2 reaction was carried out by the reaction of compound (S6,S7) with bromo ethyl acetate to get ethyl[5{4-(4- chlorobenzylidene amino)-1- naphthyl} diazenyl] -1- 1,3,4- thiadiazole-2- yl- thio] acetate (S8) and ethyl [5-{4- (2- nitrobenzylidene amino)-1- naphthyl diazenyl] -1,3,4- thiadiazole -2-yl-acetate (S9).(Fig.1)

    Bringing Background into the Foreground: Making All Classes Equal in Weakly-supervised Video Semantic Segmentation

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    Pixel-level annotations are expensive and time-consuming to obtain. Hence, weak supervision using only image tags could have a significant impact in semantic segmentation. Recent years have seen great progress in weakly-supervised semantic segmentation, whether from a single image or from videos. However, most existing methods are designed to handle a single background class. In practical applications, such as autonomous navigation, it is often crucial to reason about multiple background classes. In this paper, we introduce an approach to doing so by making use of classifier heatmaps. We then develop a two-stream deep architecture that jointly leverages appearance and motion, and design a loss based on our heatmaps to train it. Our experiments demonstrate the benefits of our classifier heatmaps and of our two-stream architecture on challenging urban scene datasets and on the YouTube-Objects benchmark, where we obtain state-of-the-art results.Comment: 11 pages, 4 figures, 7 tables, Accepted in ICCV 201

    Estimation Using Bivariate Extreme Ranked Set Sampling With Application To The Bivariate Normal Distribution

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    In this article, the procedure of bivariate extreme ranked set sampling (BVERSS) is introduced and investigated as a procedure of obtaining more accurate samples for estimating the parameters of bivariate populations. This procedure takes its strength from the advantages of bivariate ranked set sampling (BVRSS) over the usual ranked set sampling in dealing with two characteristics simultaneously, and the advantages of extreme ranked set sampling (ERSS) over usual RSS in reducing the ranking errors and hence in being more applicable. The BVERSS procedure will be applied to the case of the parameters of the bivariate normal distributions. Illustration using real data is also provided

    Impact-ionization and noise characteristics of thin III-V avalanche photodiodes

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    It is, by now, well known that McIntyre\u27s localized carrier-multiplication theory cannot explain the suppression of excess noise factor observed in avalanche photodiodes (APDs) that make use of thin multiplication regions. We demonstrate that a carrier multiplication model that incorporates the effects of dead space, as developed earlier by Hayat et al. provides excellent agreement with the impact-ionization and noise characteristics of thin InP, In/sub 0.52/Al/sub 0.48/As, GaAs, and Al/sub 0.2/Ga/sub 0.8/As APDs, with multiplication regions of different widths. We outline a general technique that facilitates the calculation of ionization coefficients for carriers that have traveled a distance exceeding the dead space (enabled carriers), directly from experimental excess-noise-factor data. These coefficients depend on the electric field in exponential fashion and are independent of multiplication width, as expected on physical grounds. The procedure for obtaining the ionization coefficients is used in conjunction with the dead-space-multiplication theory (DSMT) to predict excess noise factor versus mean-gain curves that are in excellent accord with experimental data for thin III-V APDs, for all multiplication-region widths

    Determinants of Success and Failure of Entrepreneurs of SMEs in Bangladesh- An Explorative Study

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    Entrepreneurs and entrepreneurship are significantly correlated with the economic development of a country. Entrepreneurs cannot easily succeed in doing successful business venture without facing risk that arises from internal and external conditions. So, the present study has been undertaken in order to identify the factors contributing to the success; and influencing the failure of entrepreneurs of SMEs in Bangladesh by employing sophisticated multivariate technique-Varimax Rotated Factor Analytical Technique. The study has collected and used only primary data; and consulted available literature for designing the questionnaire and study. The study has considered 18 variables responsible for failure, and 10 variables contributing to the success of entrepreneurs. The study has identified factors responsible for success of Entrepreneurs of SMEs: Relationship Factor; and Organization Factor in order of magnitude. It has identified factors influencing the failure of Entrepreneurs of SMEs: sustainable Factor, Supply Factor, and Product Related Factor in order of magnitude. The study has suggested entrepreneurs of SMEs to consider these factors while developing policies and strategies for SMEs

    Inference on Overlapping Coefficients in Two Exponential Populations

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    Three measures of overlap, namely Matusita’s measureρ , Morisita’s measure λ and Weitzman’s measure Δ are investigated in this article for two exponential populations with different means. It is well that the estimators of those measures of overlap are biased. The bias is of these estimators depends on the unknown overlap parameters. There are no closed-form, exact formulas, for those estimators variances or their exact sampling distributions. Monte Carlo evaluations are used to study the bias and precision of the proposed overlap measures. Bootstrap method and Taylor series approximation are used to construct confidence intervals for the overlap measures

    Determinants of Success and Failure of Entrepreneurs of SMEs in Bangladesh- An Explorative Study

    Get PDF
    Entrepreneurs and entrepreneurship are significantly correlated with the economic development of a country. Entrepreneurs cannot easily succeed in doing successful business venture without facing risk that arises from internal and external conditions. So, the present study has been undertaken in order to identify the factors contributing to the success; and influencing the failure of entrepreneurs of SMEs in Bangladesh by employing  sophisticated multivariate technique-Varimax Rotated Factor Analytical Technique. The study has collected and used only primary data; and consulted available literature for designing the questionnaire and study. The study has considered 18 variables responsible for failure, and 10 variables contributing to the success of entrepreneurs. The study has identified factors responsible for success of Entrepreneurs of SMEs: Relationship Factor; and Organization Factor in order of magnitude. It has identified factors influencing the failure of Entrepreneurs of SMEs: sustainable Factor, Supply Factor, and Product Related Factor in order of magnitude. The study has suggested entrepreneurs of SMEs to consider these factors while developing policies and strategies for SMEs

    A study on small business enterprises in Bangladesh : searching for growth factors and obstacles

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    Small businesses are the heart of the market-based economy with their business operations in rural and urban areas of developed and developing countries. In Bangladesh, small business enterprises are playing a significant role by contributing to the production and services, employmnet and thereby to GDP. But these are found to face servere competition and different types of constraints. As a result, these have not achieved substantial growth. In view of this, the present study is primarily aimed at identifying factors and obstacles that influence the growth of SBEs. Finally, the paper suggests some policy measures which are expected to excel the growth of SBEs
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