Majumder I.,University of Calcutta |
Chakraborty P.,University of Calcutta |
Das S.,University of Calcutta |
Kara H.,Balikesir University |
And 3 more authors.
RSC Advances | Year: 2015
An "end-off" pentadentate compartmental ligand HL has been synthesized by Mannich base condensation using p-cresol and 2-benzyl amino ethanol and structurally characterized. A dinuclear copper(ii) complex, namely [Cu2(L)(μ-OH)(H2O)(ClO4)2], has been prepared by treating HL with Cu(ClO4)2·6H2O in methanolic solution with the aim of investigating its catalytic promiscuity. Single crystal structural analysis reveals that the Cu-Cu separation is 2.9 Å. Catecholase activity of the complex has been investigated in anhydrous DMSO as well as in a DMSO-water mixture with progressively increasing the quantity of water up to a 1:1 volume ratio in order to assess the bio compatibility of the catalyst using 3,5-DTBC as a model substrate. In anhydrous DMSO the catalytic activity reaches its peak and decreases with increasing water concentration, a feature most likely due to insolubility of 3,5-DTBQ, the product formed in the catalysis, in water. The complex also shows excellent phosphatase-like activity by exploiting the Lewis acidity, the necessary requirement for that activity, under different pH. Thorough investigation reveals that no activity is observed at pH 6 but the activity increases with increasing pH and attains a maximum at pH 9. A variable temperature magnetic study shows that the two Cu centers are antiferromagnetically coupled at low temperature with a J value of -78.63 ± 1.30 cm-1. In acetonitrile medium the complex shows very exciting behavior. A new transformed ligand is generated that has been assigned as a Schiff-base ligand, 2,6-bis-[(2-hydroxy-ethylimino)-methyl]-4-methylphenol. The genesis of the new ligand is a consequence of dealkylation from HL followed by oxidation. This oxidation is counterbalanced by reduction of Cu(ii) to Cu(i) as is evidenced from isolation of [Cu(MeCN)4](ClO4) from the mixture followed by X-ray structural characterization of the species. 2015 © The Royal Society of Chemistry 2015.
Basak S.,IIEST Shibpur |
Acharya T.,IIEST Shibpur
Mobile Networks and Applications | Year: 2015
We investigate the problems of route lifetime maximization and interference to primary user minimization jointly in outage constrained stationary cognitive radio ad hoc networks. It may be noted that although, both lifetime maximization schemes in wireless ad hoc networks (WANETs) and interference minimization schemes in cognitive radio networks mostly aim to minimize transmission power of nodes in a given routing session, using any one of them to achieve both of the said objectives simultaneously does not yield satisfactory performance. In this paper, first, we study both minimum total interference (MTI) and maximum lifetime (ML) routing problems separately as joint power allocation and routing problems. Next closed form expressions for power allocation for both MTI and ML strategies are derived and, from these solutions, we obtain corresponding routing metrics to solve the routing problems. Moreover, closed form expression for a hybrid-ML-MTI power allocation approach is also proposed followed by a new hybrid routing metric. We also present implementation issues related to the proposed hybrid routing and power allocation scheme. Extensive simulation results are used to evaluate performance of our proposed schemes both in regular grid and random networks. Results show that while in grid networks, a straightforward combination of MTI routing with ML power allocation scheme strikes a good balance between interference and lifetime performances, in random networks, our proposed hybrid approach is found to extend lifetime and control interference performances simultaneously in a significant manner. © 2015, Springer Science+Business Media New York.
Roy S.,IIEST Shibpur |
Bhattacharya U.,IIEST Shibpur
ACM International Conference Proceeding Series | Year: 2015
Pervasive computing has emerged as a technological renaissance in which anything and everything of the surroundings can be made to act as a computing device. With the advent of the concept of Internet of Things (IoT), the concept of computation has extended its horizon from the traditional computing devices to everything belonging to the material world. Since a long time, it has been a serious problem especially for the working mothers to take care of their kids at home. Even if those women leave their children at home with a governess, they are not free from concerns like whether the child is taken care properly, if the child is physically fit or not, whether there is any risk around the child at the current moment, whether the child is afraid and so on. The paper addresses this problem and aims in minimizing the concerns of a working mother who leaves her child at home. In this paper a smart home architecture named as Smart Mom is proposed which can give pervasive care to children at home, having age between five to fourteen years. The overall modular architecture is given here and each module is also described in details. © 2015 ACM.
Basak S.,IIEST Shibpur |
Acharya T.,IIEST Shibpur
Physical Communication | Year: 2015
An opportunistic routing problem in a cognitive radio ad hoc network is investigated with an aim to minimize the interference to primary users (PUs) and under the constraint of a minimum end-to-end data rate for secondary users (SUs). Both amplify-and-forward (AF) and decode-and-forward (DF) relaying techniques are considered for message forwarding by SU nodes in the network. Unlike popular transmit power control based solutions for interference management in cognitive radio networks, we adopt a cross layer approach. The optimization problem is formulated as a joint power control, channel assignment and route selection problem. Next, closed form expression for transmission power is derived and corresponding channel selection scheme and routing metric are designed based on this solution. The proposed route selection schemes are shown to depend not only on gains of the interference channels between SUs and PUs but also on the values of the spectrum sensing parameters at the SU nodes in the network. Two distributed routing schemes are proposed based on our analysis; (i) optimal_DF and (ii) suboptimal_AF. The routing schemes could be implemented using existing table driven as well as on demand routing protocols. Extensive simulation results are provided to evaluate performance of our proposed schemes in random multihop networks. Results show significant reduction in PUs' average interference experience and impressive performance as opportunistic routing schemes can be achieved by our schemes compared to traditional shortest path based routing schemes. Performance improvement is also reported over prominent recent schemes. © 2015 Elsevier B.V.
De P.,IIEST Shibpur |
Mandal S.,IIEST Shibpur |
Das A.,IIEST Shibpur |
Chanda B.,Electronics and Communication science Unit
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015
In this paper a method to detect the electrical circuit elements from the scanned images of electrical drawings is proposed. The method, based on histogram analysis and mathematical morphology, detects the circuit elements, for example, circuit components, wires, and generates a connectivity matrix which may be used to find similar, but spatially different looking circuit using graph isomorphism. The work may also be used for vectorization of the circuit drawings utilising the information on the segmented circuit elements and corresponding connectivity matrix. The novelty of the method lies in its simplicity and adaptability to work with a tolerable skewed image and the capability to segment symbols irrespective of their orientation. The proposed method is tested over a data-set containing more than one hundred scanned images of a variety of electrical drawings. Some of the results are presented in this paper to show the efficacy and robustness of the proposed method. © 2015 SPIE.