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排序方式: 共有1093条查询结果,搜索用时 125 毫秒
21.
Suman Mukhopadhyay Goutam Mukhopadhyay Sandip Bhattacharyya 《Journal of Failure Analysis and Prevention》2017,17(4):624-631
Failure analysis of a steel chimney used in a lime plant was carried out. The chimney broke from two different locations during a storm. During the site visit, it was observed that the chimney was dislodged from weld joints. The chimney was made up of hot rolled mild steel plates. Investigations were carried out on the failed chimney plate and welding between plates. The investigation consists of visual observation, chemical analysis, characterization of macro- and microstructures, measurement of hardness, tensile property tests and energy-dispersive spectroscopy (EDS). Calculation of wind load at the location of breakage was also carried out. EDS analysis revealed entrapment of slag inside weld. Overall analysis suggested that the failure took place due to selection of improper reconditioning technique as well as poor workmanship in welding. 相似文献
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23.
Microarray technology has made it possible to monitor the expression levels of many genes simultaneously across a number of experimental conditions. Fuzzy clustering is an important tool for analyzing microarray gene expression data. In this article, a real-coded Simulated Annealing (VSA) based fuzzy clustering method with variable length configuration is developed and combined with popular Artificial Neural Network (ANN) based classifier. The idea is to refine the clustering produced by VSA using ANN classifier to obtain improved clustering performance. The proposed technique is used to cluster three publicly available real life microarray data sets. The superior performance of the proposed technique has been demonstrated by comparing with some widely used existing clustering algorithms. Also statistical significance test has been conducted to establish the statistical significance of the superior performance of the proposed clustering algorithm. Finally biological relevance of the clustering solutions are established. 相似文献
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25.
Santosh Biswas Dipankar Sarkar Siddhartha Mukhopadhyay Amit Patra 《Discrete Event Dynamic Systems》2010,20(3):349-376
Failure diagnosability has been widely studied for discrete event system (DES) models because of modeling simplicity and computational
efficiency due to abstraction. In the literature it is often held that for diagnosability, such models can be used not only
for systems that fall naturally in the class of DES but also for the ones traditionally treated as continuous variable dynamic
systems. A class of algorithms for failure diagnosability of DES models has been successfully developed for systems where
fairness is not a part of the model. These algorithms are based on detecting cycles in the normal and the failure model that
look identical. However, there exist systems with all transitions fair where the diagnosability condition that hinges upon
this feature renders many failures non-diagnosable although they may actually be diagnosable by transitions out of a cycle.
Hence, the diagnosability conditions based on cycle detection need to be modified to hold for many real-world systems where
all transitions are fair. In this work, however, it is shown by means of an example that a system may have some transitions
fair and some unfair. A new failure diagnosability mechanism is proposed for DES models with both fair and unfair transitions.
Time complexity for deciding diagnosability of DES models with fair and unfair transitions is analyzed and compared with the
time complexities of other DES diagnosability analysis methods reported in the literature. 相似文献
26.
Though the network quality-of-service (QoS) metrics are defined in terms of technical parameters (e.g., delay, jitter, bandwidth), they are rather subjective when it comes to the end user. Oftentimes, the end user finds it difficult to express his desired QoS in such technical parameters, though he has a fair idea of what QoS he desires. In this paper, we show how translation functions can be devised and used to translate the user inputs to networking parameters that are used by various layers of the protocol stack. In particular, we consider an ad hoc network and show an interface design that uses translation functions to map user supplied inputs to parameters at the medium access control (MAC) and routing layers. These parameters, in turn, choose the right strategies that particular layer functionality can adopt, such that the QoS desired by the user is achieved. We also compute the associated costs due to the different strategies adopted. We implement the interface on ns-2 and conduct simulation experiments with randomly scattered IEEE 802.11 enabled nodes. Results show the functionality of the interface and demonstrate how delay, throughput, and network lifetime are affected when the end user seeks different levels of QoS. 相似文献
27.
Saikat Basu Manohar Karki Sangram Ganguly Robert DiBiano Supratik Mukhopadhyay Shreekant Gayaka Rajgopal Kannan Ramakrishna Nemani 《Neural Processing Letters》2017,45(3):855-867
Learning sparse feature representations is a useful instrument for solving an unsupervised learning problem. In this paper, we present three labeled handwritten digit datasets, collectively called n-MNIST by adding noise to the MNIST dataset, and three labeled datasets formed by adding noise to the offline Bangla numeral database. Then we propose a novel framework for the classification of handwritten digits that learns sparse representations using probabilistic quadtrees and Deep Belief Nets. On the MNIST, n-MNIST and noisy Bangla datasets, our framework shows promising results and outperforms traditional Deep Belief Networks. 相似文献
28.
Anindya Kanti De Achintya Mukhopadhyay Ishwar K. Puri 《Microfluidics and nanofluidics》2008,4(5):463-470
The suitable surface modification of microfluidic channels can enable a neutral electrolyte solution to develop an electric
double layer (EDL). The ions contained within the EDL can be moved by applying an external electric field, inducing electroosmotic
flows (EOFs) that results in associated stirring. This provides a solution for the rapid mixing required for many microfluidic
applications. We have investigated EOFs generated by applying a steady electric field across a square cavity that has homogenous
electric potentials along its walls. The flowfield is simulated using the lattice Boltzmann method. The extent of mixing is
characterized for different electrode configurations and electric field strengths. We find that rapid mixing can be achieved
by using this simple configuration which increases with increasing electric field strength. The mixing time for water-soluble
organic molecules can be decreased by four orders of magnitude by suitable choice of wall zeta potential and electric field.
We dedicate this paper to the memory of our colleagues Professors Kevin Granata and Liviu Librescu who fell tragically on
April 16, 2007 while answering their call to serve higher education. They continue to inspire us. AM gratefully acknowledges
support from Jadavpur University under the World Bank funded Technical Education Quality Improvement Programme of the Government
of India and the hospitality of the Virginia Tech ESM Department where he conducted a portion of this work. 相似文献
29.
In the finitely recursive process (FRP) model of discrete event systems (DES), concepts about processes and process operators have been introduced. An infinite set of process expressions or functions can be built recursively through function composition using a few elementary operators. Given any process realization, it is important to find out whether the process is bounded, i.e., whether it has a finite state realization. In the FRP setting this translates to the problem of finding out whether the set of post-process expressions is finite or not. In Cieslak and Varaiya (1990) it has been shown that the boundedness problem is undecidable for general FRPs. This paper investigates the decidability of the problem for subclasses of FRP. In Inan and Varaiya (1988), it was conjectured that the set of functions that can be recursively generated using the parallel composition operator and different change operators (i.e. without using the sequential composition operator) will be finite and FRPs constructed over this set of functions will naturally be bounded. In the present work a counterexample has been provided to disprove the conjecture about the finiteness of the above set of functions. However, using a suitable post-process computation procedure, it has been shown here that the FRPs, built recursively over this set of functions, are bounded 相似文献
30.
Effect of shielding gas mixture on gas metal arc welding of HSLA steel using solid and flux-cored wires 总被引:1,自引:0,他引:1
S. Mukhopadhyay T.K. Pal 《The International Journal of Advanced Manufacturing Technology》2006,29(3-4):262-268
In this work, gas metal arc welding of high strength-low alloy (HSLA) steel with solid- and flux-cored arc welding wires using
different shielding gas compositions was performed. The composition of filler wire and shielding gas in gas metal arc welds
of HSLA steel determines the inclusion characteristics, microstructure and mechanical properties. Thus, acceptable weld metal
properties in HSLA steel using gas metal arc welding (GMAW) process could be achieved with the proper combination of filler
wire and shielding gas composition. 相似文献