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9. Checking Observational Purity of Procedures

Author

Arora, Himanshu, Komondoor, Raghavan, and Ramalingam, G.

Subjects
Computer Science - Software Engineering, Computer Science - Programming Languages
Abstract

Verifying whether a procedure is observationally pure is useful in many software engineering scenarios. An observationally pure procedure always returns the same value for the same argument, and thus mimics a mathematical function. The problem is challenging when procedures use private mutable global variables, e.g., for memoization of frequently returned answers, and when they involve recursion. We present a novel verification approach for this problem. Our approach involves encoding the procedure's code as a formula that is a disjunction of path constraints, with the recursive calls being replaced in the formula with references to a mathematical function symbol. Then, a theorem prover is invoked to check whether the formula that has been constructed agrees with the function symbol referred to above in terms of input-output behavior for all arguments. We evaluate our approach on a set of realistic examples, using the Boogie intermediate language and theorem prover. Our evaluation shows that the invariants are easy to construct manually, and that our approach is effective at verifying observationally pure procedures., Comment: FASE 2019

Published
2019

11. Scaling Ordered Stream Processing on Shared-Memory Multicores

Author

Prasaad, Guna, Ramalingam, G., and Rajan, Kaushik

Subjects
Computer Science - Databases
Abstract

Many modern applications require real-time processing of large volumes of high-speed data. Such data processing needs can be modeled as a streaming computation. A streaming computation is specified as a dataflow graph that exposes multiple opportunities for parallelizing its execution, in the form of data, pipeline and task parallelism. On the other hand, many important applications require that processing of the stream be ordered, where inputs are processed in the same order as they arrive. There is a fundamental conflict between ordered processing and parallelizing the streaming computation. This paper focuses on the problem of effectively parallelizing ordered streaming computations on a shared-memory multicore machine. We first address the key challenges in exploiting data parallelism in the ordered setting. We present a low-latency, non-blocking concurrent data structure to order outputs produced by concurrent workers on an operator. We also propose a new approach to parallelizing partitioned stateful operators that can handle load imbalance across partitions effectively and mostly avoid delays due to ordering. We illustrate the trade-offs and effectiveness of our concurrent data-structures on micro-benchmarks and streaming queries from the TPCx-BB benchmark. We then present an adaptive runtime that dynamically maps the exposed parallelism in the computation to that of the machine. We propose several intuitive scheduling heuristics and compare them empirically on the TPCx-BB queries. We find that for streaming computations, heuristics that exploit as much pipeline parallelism as possible perform better than those that seek to exploit data parallelism.

Published
2018

31. Green Synthesis of Bimetallic Cu−Cd Nanoparticles and its Catalytic Activity in Pyrido [2,3‐d;6,5‐d] Dipyrimidine Derivatives.

Author

Kopperundevi, J., Ashokkumar, D., Gopalakrishnan, M., and Ramalingam, G.

Subjects
METAL nanoparticles, BLOOD sugar, CATALYTIC activity, X-ray diffraction, MOLECULAR docking
Abstract

Green synthesis nanoparticles have gained interest in recent years due to their environmental friendliness and sustainability. The current study focuses on the green synthesis of BMNP using spearmint leaves as a reducing and stabilizing agent. Because of their excellent catalytic characteristics, the synthesized bimetallic nanoparticles function as an effective catalyst in pyrido[2,3‐d:6,5‐d] pyrimidine derivatives. The synthesized nanoparticles are characterized using a variety of techniques, including FT‐IR analysis, SEM & EDX, XRD, and TEM. The FT‐IR study shows a reduction in functional groups in the leaf extract, confirming the metal nanoparticles' stretching. SEM and EDX studies confirm the shape and elemental composition of bimetallic nanoparticles. XRD investigation showed that the synthesized NPs are crystalline, and the Scherrer equation was used to calculate the average crystallite size. The calculated size was 49 nm. TEM analysis confirms the core‐shell nature of BMNPs. The synthesized nanoparticles acted as a superior catalyst in pyrido[2,3‐d:6,5‐d] dipyrimidines derivatives. in the synthetic procedure, BMNPs enhanced the catalytic activity and reduced the reaction time with more yield, Compared to the previous study. and the synthesized compound [1–5] has been confirmed by FT‐IR, 1H‐NMR, and 13C‐NMR analysis. and it has given better results in in‐vivo anti‐diabetic activity by Streptozotocin nicotinamide. This induced model adult male albino Wistar derivatives show significant fasting blood glucose levels when compared to metformin hydrochloride. and its evaluated molecular docking study, exhibit excellent CDDOCKER energy. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Logical Concurrency Control from Sequential Proofs

Author

Deshmukh, Jyotirmoy, Ramalingam, G., Ranganath, Venkatesh-Prasad, and Vaswani, Kapil

Subjects
Computer Science - Programming Languages, Computer Science - Logic in Computer Science, Computer Science - Software Engineering, D.1.3, D.2.4, F.3.1
Abstract

We are interested in identifying and enforcing the isolation requirements of a concurrent program, i.e., concurrency control that ensures that the program meets its specification. The thesis of this paper is that this can be done systematically starting from a sequential proof, i.e., a proof of correctness of the program in the absence of concurrent interleavings. We illustrate our thesis by presenting a solution to the problem of making a sequential library thread-safe for concurrent clients. We consider a sequential library annotated with assertions along with a proof that these assertions hold in a sequential execution. We show how we can use the proof to derive concurrency control that ensures that any execution of the library methods, when invoked by concurrent clients, satisfies the same assertions. We also present an extension to guarantee that the library methods are linearizable or atomic.

Published
2011
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42. Liquid phase selective oxidation of veratryl alcohol to veratraldehyde using pure and Mg-doped copper chromite catalysts

Author

Jagadeesan, S., primary, Prathipa, V., additional, Ragupathi, C., additional, Ramalingam, G., additional, Narayanan, S., additional, Tamizhdurai, P., additional, Rajendran, A., additional, Yadav, Krishna Kumar, additional, Albakri, Ghadah Shukri, additional, Abbas, Mohamed, additional, and Alreshidi, Maha Awjan, additional

Published
2024
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47. Photocatalytic oxygen evolution reaction for energy conversion and storage of functional nanomaterials

Author

Kaviyarasu, K., primary, Magdalane, C. Maria, additional, Raja, A., additional, Matinise, N., additional, Mayedwa, N., additional, Mongwaketsi, N., additional, Letsholathebe, Douglas, additional, Mola, G.T., additional, AbdullahAl-Dhabi, Naif, additional, Arasu, Mariadhas Valan, additional, Ramalingam, G., additional, Mohamed, S.B., additional, Isaev, Abdulgalim B., additional, Kanimozhi, K., additional, Bashir, A.K.H., additional, Kennedy, J., additional, and Maaza, M., additional

Published
2020
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49. Green Synthesis of Bimetallic Nanoparticles and its Catalytic Activity of Multicomponent Reactions and Antibacterial Activity.

Author

Kopperundevi, J., Gopalakrishnan, M., and Ramalingam, G.

Subjects
BIMETALLIC catalysts, ANTIBACTERIAL agents, CATALYTIC activity, NANOPARTICLES, X-ray diffraction, PLANT metabolites
Abstract

This present research work focuses on synthesizing Ag−Cu bimetallic nanoparticles utilizing an aqueous extract leaf of Excoecaria agallocha, employing a green synthesis route. The incorporation of silver (Ag) with copper (Cu) induces synergistic effects that enhance reaction kinetics and reduce the multicomponent reaction time. The catalysts synthesized through this environmentally friendly approach were thoroughly characterized using various analytical techniques, including HR‐TEM, XRD, SEM‐EDX, UV‐Vis Spectrophotometry, and FT‐IR. The UV‐visible spectrum displayed a peak at 257 nm, while the FT‐IR spectrum exhibited peaks at 574 cm−1, indicative of bimetallic peak reductions attributed to the influence of plant metabolites. HR‐TEM and XRD revealed the crystalline with (111), (200), (111), (200), and (220) plane values and shapes of BMNPs. Furthermore, the Ag−Cu bimetallic nanoparticles demonstrated outstanding catalytic performance with high product yield, along with notable reusability and recyclability and excellent antimicrobial activity when compared with commercial antibacterial chloramphenicol. [ABSTRACT FROM AUTHOR]

Published
2024
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