Abhishek Kumar - Academia.edu (original) (raw)

Papers by Abhishek Kumar

22nd International Conference on Data Engineering Workshops (ICDEW'06), 2006

Recent research on data streaming algorithms has provided powerful tools to efficiently monitor v... more Recent research on data streaming algorithms has provided powerful tools to efficiently monitor various characteristics of traffic passing through a single network link or node. However, it is often desirable to perform data streaming analysis on the traffic aggregated over hundreds or even thousands of links/nodes, which will provide network operators with a holistic view of the network operation. Shipping raw traffic data to a centralized location (i.e., "raw aggregation") for streaming analysis is clearly not a feasible approach for a large network. In this paper, we propose a set of novel Distributed Collaborative Streaming (DCS) algorithms that allow scalable and efficient monitoring of aggregated traffic without the need for raw aggregation. Our algorithms target the specific network monitoring problem of finding common content in the Internet traffic traversing several nodes/links, which has applications in network-wide intrusion detection, early warning for fast propagating worms, and detection of hot objects and spam traffic. We evaluate our algorithms through extensive simulations and experiments on traffic traces collected from a tier-1 ISP. The experimental results demonstrate that our algorithms can effectively detect common content in the traffic traversing across a large network.

Journal of Mechanical Science and Technology, 2019

In order to investigate both static and dynamic characteristics of composite plates and validate ... more In order to investigate both static and dynamic characteristics of composite plates and validate a contemporary, non-invasive experimental technique a comparative experimental and numerical analysis was performed. Three, geometrically the same but different in ply orientation, carbon-epoxy laminates were tested in both healthy and damaged conditions. Damages were inflicted in a shape of horizontal crack. Experiments and numerical simulations were performed by digital image correlation (DIC) and finite element method (FEM), respectively. Obtained time-responses of the tested structures were fast Fourier transformed (FFT) to frequency domain for a clearer understanding of natural frequencies and oscillation modes. Results are presented in tabular and graphical form. The overall correspondence of two sets of structural displacements is satisfactory. Some discrepancies might be contributed to the idealized geometry and restraint consideration. Also, due to the fast damping of higher tones, the errors in determining higher natural frequencies increase but still remain in 5 % range.

Sensors and Actuators B: Chemical, 2015

ABSTRACT The sensing properties of tetra-tert-butyl copper phthalocyanine (ttb-CuPc) toward tolue... more ABSTRACT The sensing properties of tetra-tert-butyl copper phthalocyanine (ttb-CuPc) toward toluene at room temperature are reported in this manuscript. Thin films of ttb-CuPc were obtained by thermal evaporation. The similarities between powdered and layered material have been confirmed by FTIR analysis. Taking into consideration the interactions involved between material and the target gas, Quartz Crystal Microbalance (QCM) was chosen as transducer. The key role of tertiary butyl groups grafted at the periphery of the phthalocyanine ring on toluene sensitivity has been firstly established. Despite reproducible frequency shifts for toluene exposures at the same concentration, sensor drifts were observed and attributed to temperature effects on quartz crystal. Such thermal influence on sensor responses has been minimized by short exposure times and temperature compensation on sensor signal. The strong affinity of ttb-CuPc to toluene as compared to other phthalocyanines, the repeatability of sensor responses, the reversibility of involved gas/material interactions, a resolution higher than 10 ppm and a threshold of detection lower than 35 ppm have been established from experiments. The partial selectivity has been also highlighted toward others gases like CO, NO2, H2S and xylene. At last, the relevance of metallo-phthalocyanine thin films as sensitive coatings on QCM devices to detect volatile organic compounds in real-time situation will be discussed.

Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies.

Searching for content in peer-to-peer networks is an interesting and challenging problem. Queries... more Searching for content in peer-to-peer networks is an interesting and challenging problem. Queries in Gnutella-like unstructured systems that use flooding or random walk to search must visit ¢ ¤ £ ¦ ¥ § nodes in a network of size ¥ , thus consuming significant amounts of bandwidth. In this paper, we propose a query routing protocol that allows low bandwidth consumption during query forwarding using a low cost mechanism to create and maintain information about nearby objects. To achieve this, our protocol maintains a lightweight probabilistic routing table at each node that suggests the location of each object in the network. Following the corresponding routing table entries, a query can reach the destination in a small number of hops with high probability. However, maintaining routing tables in a large and highly dynamic network requires non-traditional mechanisms. We design a novel data structure called an Exponentially Decaying Bloom Filter (EDBF) that encodes such probabilistic routing tables in a highly compressed manner, and allows for efficient aggregation and propagation. The search primitives provided by our system can be used to search for single keys or multiple keywords with equal ease. Analytical modeling of our design predicts significant improvements in search efficiency, verified through extensive simulations in which we observed an order of magnitude reduction in query path length over previous proposals.

Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology, 2015

ABSTRACT

Proceedings of the First International Conference on Intelligent Human Computer Interaction, 2009

Abstract. Proteins are highly complex and flexible structures. Rendering tools are often used to ... more Abstract. Proteins are highly complex and flexible structures. Rendering tools are often used to study their dynamics, functions and in some cases even deformations that arise due to slow dynamics. In this work, we present ProVis, a visualization tool for 3-dimensional rendering ...

AIChE Journal, 2015

in Wiley Online Library (wileyonlinelibrary.com) A new strategy for screening of solvents for sul... more in Wiley Online Library (wileyonlinelibrary.com) A new strategy for screening of solvents for sulfur, nitrogen, and aromatic compounds removal from gas oil is presented. This ranking is based on comparative assessment of solvents' capacity, selectivity, performance, and newly defined industrial usability indices. Twenty eight solvents comprising of six most widely used industrially proven conventional solvents and 22 imidazolium-based ionic liquids solvents were selected to illustrate the strategy. The solvents were ranked for removal of sulfur compounds namely benzothiophene, dibenzothiophene and their alkylated derivatives, and nitrogenous compounds namely quinoline, indole and carbazole from gas oil. Performance index (P I) which combines the effect of both capacity and selectivity seems to be better index than individual capacity and selectivity indices to rank the solvents. Industrial usability index (S IUI) of solvents which includes P I and process complexity factor for solvent recovery section seems more practical and realistic criteria for solvent assessment.

ABSTRACT Objectives: Few recent studies have highlighted the utility of 18F-DOPA imaging in carci... more ABSTRACT Objectives: Few recent studies have highlighted the utility of 18F-DOPA imaging in carcinoid tumors. 68Ga-DOTANOC PET/CT, however, has already been established in many countries for the evaluation of carcinoid tumors. Thus, a prospective trial was designed for a head-to-head comparison of 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT. Methods: Twenty eight patients with biopsy proven carcinoid tumors were prospectively enrolled and scheduled for 68Ga-DOTANOC and 18F-DOPA PET/CT. These patients were scanned for staging/restaging, detection of recurrence and for evaluation of response to therapy. Both the studies were conducted, in random orders, within three weeks time interval. The scans were reported independently by two experienced nuclear medicine physicians. The readers were blinded to the clinical and biochemical details. PET/CT results were correlated with conventional imaging, and when possible with histopathology. Results: The most common primary tumor site was the pancreas followed by the ileum. One primary site was localized to lung and one in lateral ventricle. The most common metastatic site was liver. Either on patient-basis (sensitivity- 96% vs 71%) or on lesion-basis (92 vs 63), 68Ga-DOTANOC scans picked up more disease compared to 18F-DOPA imaging. Conclusions: Overall, 68Ga-DOTANOC showed superior sensitivity in evaluation of primary carcinoid tumors as well as metastatic involvement of liver, lymph node and bone. Moreover, 68Ga-DOTANOC PET positivity indicates somatostatin receptor expression, thus guiding further management with octreotide and/or radiopeptide therapy

Methods in Cell Biology, 2010

The nucleus is maintained in a prestressed state within eukaryotic cells, stabilized mechanically... more The nucleus is maintained in a prestressed state within eukaryotic cells, stabilized mechanically by chromatin structure and other nuclear components on its inside, and cytoskeletal components on its outside. Nuclear architecture is emerging to be critical to the governance of chromatin assembly, regulation of genome function and cellular homeostasis. Elucidating the prestressed organization of the nucleus is thus important to understand how the nuclear architecture impinges on its function. In this chapter, various chemical and mechanical methods have been described to probe the prestressed organization of the nucleus.

Endoscopic Ultrasound, 2014

Leiomyosarcoma of the pulmonary vasculature is an extremely rare condition that has not been prev... more Leiomyosarcoma of the pulmonary vasculature is an extremely rare condition that has not been previously diagnosed by endobronchial ultrasound (EBUS) bronchoscopy. We present the case of a 43-year-old white male with a history of leiomyosarcoma who was diagnosed with pulmonary embolism 2 years ago. As the fi lling defects on follow-up chest computed tomography continued to worsen despite anticoagulation, EBUS-guided transbronchial needle aspiration (EBUS-TBNA) of the right pulmonary artery lesion was safely and successfully performed. Cytopathological examination revealed the "thrombus" to be metastatic leiomyosarcoma. In experienced hands, and carefully selected cases, EBUS-TBNA seems to be a safe and effective in diagnosing thoracic endovascular lesions.

Dentistry, 2013

ABSTRACT Introduction: Identifying patient's expectations for treatment has positive impa... more ABSTRACT Introduction: Identifying patient's expectations for treatment has positive impact on both clinician and the patient. It helps to build a good rapport between them. It reduces the level of discomfort and avoids pitfalls on the part of the clinician. A valid and reliable method to measure patient's expectation is very useful in carrying out any treatment. This study was designed to develop a valid and reliable Nepali version of patient's expectation of orthodontic treatment questionnaire. Material and methodology: A convenience sample of 390 subjects with an age group of 18-28 (mean 28.88 ± 1.6) years (Male=172, Female=178) reporting for Orthodontic treatment were included for this study. Reliability of the scale was tested by Cronbach's alpha coefficient and coefficient of correlation. The retest reliability was also tested using correlation coefficient between items and scale. Construct validity was tested by means of a cognitive interview which was conducted among 100 participants. Results: The questionnaire demonstrated good internal consistency with over all Cronbach's alpha of 0.72. There was a good correlation among items with the corrected item total correlation of >0.3 achieved in over 50% of the items. Test-retest analysis was conducted on 290 subjects and the responses recorded were statistically significant using spearman's correlation coefficient suggesting a good reliability. The construct validity was assessed by measuring the agreement between questionnaire filled by the subject and filled by the researcher on the basis of cognitive interview of the same subjects. There was a good level of agreement for all the items ranging from 0.83 to 0.98. Conclusion: A reliable and valid Nepali version of patient's expectation of orthodontic treatment was developed. Copyright: © 2012 Singh VP, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Health Renaissance, 2013

The term Riga-Fede disease has been used historically to describe traumatic ulceration that occur... more The term Riga-Fede disease has been used historically to describe traumatic ulceration that occurs on the ventral surface of tongue in neonates and infants. The natal and neonatal tooth have been reported to cause ulceration on the ventral surface of the tongue which may affect the child.s feeding habits. This appearance was described by Riga and Fede and hence been termed as Riga-Fede disease. It is important to diagnose the lesion early and treat it by eliminating the cause of trauma to avoid untoward complications. Treatment option can be either conservative or extraction of natal and neonatal tooth. This paper presents a case of Riga-Fede disease resolved by conservative treatment i.e., grinding, after which the infant started feeding normally. Health Renaissance, January-April 2013; Vol. 11 No.1; 174-176 DOI: http://dx.doi.org/10.3126/hren.v11i2.8230

Evangelische Theologie, 2005

World Journal of Microbiology and Biotechnology, 2012

Spore germination based assay involves the transformation of dormant spores of Bacillus stearothe... more Spore germination based assay involves the transformation of dormant spores of Bacillus stearothermophilus 953 into active vegetative cells. The inhibition of germination process specifically in presence of antibiotic residues was used as a novel approach for monitoring target contaminants in milk. The indicator organism i.e., B. stearothermophilus 953 was initially allowed to sporulate by seeding in sporulation medium and incubating at 55°C for 18 ± 2 h. The spores exhibited a typical chain behavior as revealed through phase contrast microscopy. The minimal medium inoculated with activated spores was incubated at 64°C for 2-3 h for germination and outgrowth in presence of specific germinant mixture containing dextrose, whey powder and skimmed milk powder added in specific ratio along with reconstituted milk as negative control and test milk samples. The change in color of the medium from purple to yellow was used as criteria for detection of antibiotic residues in milk. The efficiency of the developed assay was evaluated through a surveillance study on 228 samples of raw, pasteurized and dried milks and results were compared with AOAC approved microbial receptor assay. The presence of antibiotic level was 10.08 % at Codex maximum residual limit having false positive result only in 0.43 % of the samples. The results of the present investigation suggest that developed spore based assay can be a practical solution to dairy industry for its application at farm level, milk processing units, independent testing and R & D centres in order to comply with the legal requirements set by Codex.

Journal of High Energy Physics, 2010

Tetrahedron, 2014

We report the synthesis of a self organizable and water dispersible bis PEGylated (bis polyethyle... more We report the synthesis of a self organizable and water dispersible bis PEGylated (bis polyethyleneglycolated) curcumin (1) using an efficient synthetic method. Compound 1 forms nanoparticles on the order of 90 nm in water. Even though it forms nanoparticles, compound 1 interacts strongly with metal ions, Al þ3 , Cu þ2 , and Hg þ2. Fluorescence and absorption spectroscopic techniques were employed to investigate the metal interactions of these nanoparticles. Al þ3 and Cu þ2 ions interact with compound 1 leading to enhancement and dramatic quenching in the fluorescence of the latter in 100% water, respectively. Addition of Hg þ2 ions to compound 1 in water produces a ratiometric change in the absorption spectra of the nanoparticles. Although PEGylated curcumin derivatives were reported in the past, there have been no reports on their self organization into nanoparticles and extensive studies on their metal interaction properties in 100% water using its fluorescence and absorption properties.

Pediatric Emergency Care, 2008

Hip pain in children often poses a diagnostic dilemma. Septic arthritis, Perthes disease, and sli... more Hip pain in children often poses a diagnostic dilemma. Septic arthritis, Perthes disease, and slipped capital femoral epiphysis are among the most important causes. Pyomyositis involving muscles around the hip can present with similar features as septic arthritis and are difficult to diagnose because of their rarity and indolent presentation. Obturator internus and iliopsoas muscle abscess have been most commonly reported, with only 1 such report on isolated obturator externus muscle abscess. Routine laboratory investigations are nonspecific, and the diagnosis rests on imaging modalities. Magnetic resonance scan is the most useful investigation in the diagnosis and can pick up early changes in the muscle. Treatment involves appropriate antibiotic therapy with or without drainage. Most cases resolve completely. We report here a case of isolated obturator externus muscle abscess in an 11-year-old child illustrating the similarities with septic arthritis of hip and problems encountered during diagnosis and management.

Natural Hazards, 2013

The Himalayas are one of very active seismic regions in the world where devastating earthquakes o... more The Himalayas are one of very active seismic regions in the world where devastating earthquakes of 1803 Bihar-Nepal,

Mineral Processing and Extractive Metallurgy Review, 2009

Among many emerging fine beneficiation methods, the liquid/solid fluidization technique has becom... more Among many emerging fine beneficiation methods, the liquid/solid fluidization technique has become the operator's choice owing to its superior performance. In this article, the subject is revisited with the aim to enhance process efficiency through basic understanding of the ...