Shiv Nadar University

About: Shiv Nadar University is a education organization based out in Dadri, Uttar Pradesh, India. It is known for research contribution in the topics: Population & Graphene. The organization has 1015 authors who have published 1924 publications receiving 18420 citations.

A Flexible and Efficient Indexing Scheme for Placement of Top-Utility Itemsets for Different Slot Sizes

Abstract: Utility mining has been emerging as an important area in data mining. While existing works on utility mining have primarily focused on the problem of finding high-utility itemsets from transactional databases, they implicitly assume that each item occupies only one slot. However, in many real-world scenarios, the number of slots consumed by different items typically varies. Hence, this paper considers that a given item may physically occupy any fixed (integer) number of slots. Thus, we address the problem of efficiently determining the top-utility itemsets when a given number of slots is specified as input. The key contributions of our work are three-fold. First, we present an efficient framework to determine the top-utility itemsets for different user-specified number of slots that need to be filled. Second, we propose a novel flexible and efficient index, designated as the STUI index, for facilitating quick retrieval of the top-utility itemsets for a given number of slots. Third, we conducted an extensive performance evaluation using real datasets to demonstrate the overall effectiveness of the proposed indexing scheme in terms of execution time and utility (net revenue) as compared to a recent existing scheme.

Adaptive phase estimation through a genetic algorithm

Abstract: The authors propose and experimentally demonstrate an adaptive phase estimation protocol using a genetic algorithm, showing convergence to the true parameter value by using very limited data.

Entrainer based economical design and plantwide control study for Tetrahydrofuran/Water separation process

Abstract: In this work, the control structure design for a continuous extractive distillation scheme using entrainers for separating THF–water azeotropic mixture into high purity product (THF) has been studied. The selection of suitable entrainer for the undertaken process was purely based on economical design criteria where total annualised cost (TAC) for different entrainers were first calculated and further compared. Once the suitable entrainer was selected based on the design economics, later the plantwide control structure was evaluated for disturbance rejection capabilities and smooth process operations in the face of feed throughput and composition change. For economical design operations, the recycle rate of entrainers has to be kept around a minimum recycle rate. However, operating below minimum entrainer recycle rate leads the product purity to fall sharply in conventional control structure designs due to THF–Water azeotropic constraints. The presented control structure design in this works ensures that product purity is not lost even in case of sever disturbances in feed throughput (by ±10%) or a changed feed composition (by ±5%).

Rationally designed donor-acceptor scheme based molecules for applications in opto-electronic devices.

Abstract: Several donor (D)–acceptor (A) based molecules are rationally designed by adopting three different schemes in which the conjugation length, strength of the donor and acceptor moieties, and planarity of the molecules are varied. These variations are made by introducing a π-conjugated linkage unit, terminating the ends of the moieties by different electron donating and accepting functional groups, and fusing the donor and acceptor moieties, respectively. Our DFT and TDDFT based calculations reveal that using the above-mentioned design schemes, the electronic and optical properties of the D–A based molecules can be largely tuned. While introduction of a linkage and fusing of moieties enhance the π–π interaction, addition of electron donating groups (–CH3, –OH, and –NH2) and electron accepting groups (–CF3, –CN, –NO2, and –NH3+) varies the strength of the donor and acceptor moieties. These factors lead to modulation of the HOMO and LUMO energy levels and facilitate the engineering of the HOMO–LUMO gap and the optical gap over a wide range of ∼0.7–3.7 eV. Moreover, on the basis of calculated ionization potential and reorganization energy, most of the investigated molecules are predicted to be air stable and to exhibit high electron mobility, with the possibility of the presence of ambipolar characteristics in a few of them. The results of our calculations not only demonstrate the examined molecules to be the potential materials for organic opto-electronic devices, but also establish an understanding of the composition–structure–property correlation, which will provide guidelines for designing and synthesizing new materials of choice.