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.
Possessing large surface area materials is vital for high sensitivity detection of analyte. We re... more Possessing large surface area materials is vital for high sensitivity detection of analyte. We report a novel, inexpensive and simple technique to make high surface area sensing interfaces using electrospinning. Conducting polymers (CP) nanotubes were made by electrospinning a solution of a catalyst (ferric tosylate) along with poly (lactic acid), which is an environment friendly biodegradable polymer. Further vapor deposition
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.
IEEE Journal on Selected Areas in Communications, 2006
Abstract Detecting the sources or destinations that have communicated with a large number of dist... more Abstract Detecting the sources or destinations that have communicated with a large number of distinct destinations or sources (ie, large" fan-out" or" fan-in") during a small time interval is an important problem in network measurement and security. Previous detection approaches are not able to deliver the desired accuracy at high link speeds (10-40 Gb/s). In this work, we propose two novel algorithms that provide accurate and efficient solutions to this problem. Their designs are based on the insight that sampling and data streaming are ...
IEEE Journal on Selected Areas in Communications, 2006
Per-flow traffic measurement is critical for usage accounting, traffic engineering, and anomaly d... more Per-flow traffic measurement is critical for usage accounting, traffic engineering, and anomaly detection. Previous methodologies are either based on random sampling (e.g., Cisco's NetFlow), which is inaccurate, or only account for the "elephants". We introduce a novel technique for measuring perflow traffic approximately, for all flows regardless of their sizes, at very high-speed (say, OC768). The core of this technique is a novel data structure called Space Code Bloom Filter (SCBF). A SCBF is an approximate representation of a multiset; each element in this multiset is a traffic flow and its multiplicity is the number of packets in the flow. The multiplicity of an element in the multiset represented by SCBF can be estimated through either of two mechanisms-Maximum Likelihood Estimation (MLE) or Mean Value Estimation (MVE). Through parameter tuning, SCBF allows for graceful tradeoff between measurement accuracy and computational and storage complexity. SCBF also contributes to the foundation of data streaming by introducing a new paradigm called blind streaming. We evaluate the performance of SCBF through mathematical analysis and through experiments on packet traces gathered from a tier-1 ISP backbone. Our results demonstrate that SCBF achieves reasonable measurement accuracy with very low storage and computational complexity.
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.
Possessing large surface area materials is vital for high sensitivity detection of analyte. We re... more Possessing large surface area materials is vital for high sensitivity detection of analyte. We report a novel, inexpensive and simple technique to make high surface area sensing interfaces using electrospinning. Conducting polymers (CP) nanotubes were made by electrospinning a solution of a catalyst (ferric tosylate) along with poly (lactic acid), which is an environment friendly biodegradable polymer. Further vapor deposition
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.
IEEE Journal on Selected Areas in Communications, 2006
Abstract Detecting the sources or destinations that have communicated with a large number of dist... more Abstract Detecting the sources or destinations that have communicated with a large number of distinct destinations or sources (ie, large" fan-out" or" fan-in") during a small time interval is an important problem in network measurement and security. Previous detection approaches are not able to deliver the desired accuracy at high link speeds (10-40 Gb/s). In this work, we propose two novel algorithms that provide accurate and efficient solutions to this problem. Their designs are based on the insight that sampling and data streaming are ...
IEEE Journal on Selected Areas in Communications, 2006
Per-flow traffic measurement is critical for usage accounting, traffic engineering, and anomaly d... more Per-flow traffic measurement is critical for usage accounting, traffic engineering, and anomaly detection. Previous methodologies are either based on random sampling (e.g., Cisco's NetFlow), which is inaccurate, or only account for the "elephants". We introduce a novel technique for measuring perflow traffic approximately, for all flows regardless of their sizes, at very high-speed (say, OC768). The core of this technique is a novel data structure called Space Code Bloom Filter (SCBF). A SCBF is an approximate representation of a multiset; each element in this multiset is a traffic flow and its multiplicity is the number of packets in the flow. The multiplicity of an element in the multiset represented by SCBF can be estimated through either of two mechanisms-Maximum Likelihood Estimation (MLE) or Mean Value Estimation (MVE). Through parameter tuning, SCBF allows for graceful tradeoff between measurement accuracy and computational and storage complexity. SCBF also contributes to the foundation of data streaming by introducing a new paradigm called blind streaming. We evaluate the performance of SCBF through mathematical analysis and through experiments on packet traces gathered from a tier-1 ISP backbone. Our results demonstrate that SCBF achieves reasonable measurement accuracy with very low storage and computational complexity.
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.
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Papers by Abhishek kumar