The Experts below are selected from a list of 17715 Experts worldwide ranked by ideXlab platform
Anantha P Chandrakasan - One of the best experts on this subject based on the ideXlab platform.
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energy efficient modulation and mac for asymmetric rf Microsensor systems
International Symposium on Low Power Electronics and Design, 2001Co-Authors: Andrew H J Wang, Seong Hwan Cho, Charles G Sodini, Anantha P ChandrakasanAbstract:Wireless Microsensor systems are used in a variety of civil and military applications. Such Microsensors are required to operate for years from a small energy source. To minimize the energy dissipation of the sensor node, RF front-end circuitry must be designed based on system level optimization of the entire network. This paper presents several energy minimization techniques derived from the unique properties of a practical short range asymmetric Microsensor system. These include energy efficient modulation schemes, appropriate multiple access protocols, and a fast turn-on transmitter architecture.
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physical layer driven protocol and algorithm design for energy efficient wireless sensor networks
ACM IEEE International Conference on Mobile Computing and Networking, 2001Co-Authors: Eugene Shih, Rex Min, Seong Hwan Cho, Alice Wang, Nathan Ickes, A Sinha, Anantha P ChandrakasanAbstract:The potential for collaborative, robust networks of Microsensors has attracted a great deal of research attention. For the most part, this is due to the compelling applications that will be enabled once wireless Microsensor networks are in place; location-sensing, environmental sensing, medical monitoring and similar applications are all gaining interest. However, wireless Microsensor networks pose numerous design challenges. For applications requiring long-term, robust sensing, such as military reconnaissance, one important challenge is to design sensor networks that have long system lifetimes. This challenge is especially difficult due to the energy-constrained nature of the devices. In order to design networks that have extremely long lifetimes, we propose a physical layer driven approach to designing protocols and algorithms. We first present a hardware model for our wireless sensor node and then introduce the design of physical layer aware protocols, algorithms, and applications that minimize energy consumption of the system. Our approach prescribes methods that can be used at all levels of the hierarchy to take advantage of the underlying hardware. We also show how to reduce energy consumption of non-ideal hardware through physical layer aware algorithms and protocols.
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energy efficient protocols for low duty cycle wireless Microsensor networks
International Conference on Acoustics Speech and Signal Processing, 2001Co-Authors: Seong Hwan Cho, Anantha P ChandrakasanAbstract:Emerging distributed wireless Microsensor networks will enable the reliable and fault tolerant monitoring of the environment. Such Microsensors are required to operate for years from a small energy source, while maintaining a reliable communication link to the base station. The design of energy-aware communication protocols can have a dramatic impact on the network lifetime for such applications. A detailed communication energy model, obtained from measurements, is introduced that incorporates the non-ideal behavior of the physical layer electronics. This includes the start-up energy cost of the RF transceiver, which dominates energy dissipation for short packet sizes. Using this model, various communication layer protocols are explored for asymmetrical sensor networks such as machine monitoring. The paper also proposes the use of a variable bandwidth allocation scheme that exploits spatial distribution of sensors.
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energy efficient link layer for wireless Microsensor networks
Proceedings IEEE Computer Society Workshop on VLSI 2001. Emerging Technologies for VLSI Systems, 2001Co-Authors: Eugene Shih, Benton H Calhoun, Anantha P ChandrakasanAbstract:Wireless Microsensors are being used to form large, dense networks for the purposes of long-term environmental sensing and data collection. Unfortunately these networks are typically deployed in remote environments where energy sources are limited. Thus, designing fault-tolerant wireless Microsensor networks with long system lifetimes can be challenging. By applying energy-efficient techniques at all levels of the system hierarchy, system lifetime can be extended. In this paper, energy-efficient techniques that adapt underlying communication parameters will be presented in the context of wireless Microsensor networks. In particular, the effect of adapting link and physical layer parameters, such as output transmit power and error control coding, on system energy consumption will be examined.
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an architecture for a power aware distributed Microsensor node
Signal Processing Systems, 2000Co-Authors: Manish Bhardwaj, Amit Sinha, Eugene Shih, Andrew Z Wang, Anantha P ChandrakasanAbstract:Networks of distributed Microsensors are emerging as a compelling solution for a wide range of data gathering applications. Perhaps the most substantial challenge facing designers of small but long-lived Microsensor nodes is the need for significant reductions in energy consumption. We propose a power-aware design methodology that emphasizes the graceful scalability of energy consumption with factors such as available resources, event frequency, and desired output quality, at all levels of the system hierarchy. Our architecture for a power-aware Microsensor node highlights the collaboration between software that is capable of energy-quality tradeoffs and hardware with scalable energy consumption.
Eric S Mclamore - One of the best experts on this subject based on the ideXlab platform.
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self referencing luminescent optrodes for non invasive real time measurement of extracellular flux
Proceedings of SPIE, 2011Co-Authors: Eric S Mclamore, Marshall D Porterfield, Richard B. Borgens, Margaret Katherine BanksAbstract:Autonomous technologies are needed which are capable of sensing real time changes in biophysical transport across cell membranes/organelles. These technologies must not only be highly sensitive/selective, but must also be minimally invasive/intrusive, causing no significant physical/chemical effects on cell behavior. Challenges with mainstream technologies (e.g., assays, fluorescent dyes, Microsensors) include signal noise/drift, low temporal resolution, requirement of large sample sizes, cytoxicity, organelle sequestration, and intracellular buffering. Recent advancements in fiber optics have greatly enhanced the performance of Microsensors (e.g., increased sensitivity/selectivity, response time), but used in concentration mode near cells/tissues these sensors suffer from poor signal to noise ratio. Work over the last few decades has advanced Microsensor utility through sensing modalities that extend and enhance the data recorded by sensors. This technique, known as self-referencing, converts static micro/nanosensors with otherwise low signal-to-noise ratios into dynamic flux sensors capable of filtering out signals not associated with active transport by acquisition and amplification of differential signals. Here, we demonstrate the use of a self-referencing referencing frequency domain fiber optic Microsensor containing a quenched dye (platinum tetrakis-pentafluorophenyl porphyrin) for quantifying cell/tissue flux in biomedical, agricultural, and environmental applications.
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a self referencing platinum nanoparticle decorated enzyme based microbiosensor for real time measurement of physiological glucose transport
Biosensors and Bioelectronics, 2011Co-Authors: Eric S Mclamore, Margaret Katherine Banks, David Benjamin Jaroch, Jin Shi, Jonathan C Claussen, A Uchida, Yan Jiang, Wen Zhang, Shawn S Donkin, Kimberly K BuhmanAbstract:Glucose is the central molecule in many biochemical pathways, and numerous approaches have been developed for fabricating micro biosensors designed to measure glucose concentration in/near cells and/or tissues. An inherent problem for Microsensors used in physiological studies is a low signal-to-noise ratio, which is further complicated by concentration drift due to the metabolic activity of cells. A Microsensor technique designed to filter extraneous electrical noise and provide direct quantification of active membrane transport is known as self-referencing. Self-referencing involves oscillation of a single Microsensor via computer-controlled stepper motors within a stable gradient formed near cells/tissues (i.e., within the concentration boundary layer). The non-invasive technique provides direct measurement of trans-membrane (or trans-tissue) analyte flux. A glucose micro biosensor was fabricated using deposition of nanomaterials (platinum black, multiwalled carbon nanotubes, Nafion) and glucose oxidase on a platinum/iridium microelectrode. The highly sensitive/selective biosensor was used in the self-referencing modality for cell/tissue physiological transport studies. Detailed analysis of signal drift/noise filtering via phase sensitive detection (including a post-measurement analytical technique) are provided. Using this highly sensitive technique, physiological glucose uptake is demonstrated in a wide range of metabolic and pharmacological studies. Use of this technique is demonstrated for cancer cell physiology, bioenergetics, diabetes, and microbial biofilm physiology. This robust and versatile biosensor technique will provide much insight into biological transport in biomedical, environmental, and agricultural research applications.
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Self-referencing optrodes for measuring spatially resolved, real-time metabolic oxygen flux in plant systems
Planta, 2010Co-Authors: Eric S Mclamore, David Benjamin Jaroch, M. Rameez Chatni, D. Marshall PorterfieldAbstract:The ability to non-invasively measure metabolic oxygen flux is a very important tool for physiologists interested in a variety of questions ranging from basic metabolism, growth/development, and stress adaptation. Technologies for measuring oxygen concentration near the surface of cells/tissues include electrochemical and optical techniques. A wealth of knowledge was gained using these tools for quantifying real-time physiology. Fiber-optic microprobes (optrodes) have recently been developed for measuring oxygen in a variety of biomedical and environmental applications. We have adopted the use of these optical Microsensors for plant physiology applications, and used the Microsensors in an advanced sensing modality known as self-referencing. Self-referencing is a non-invasive Microsensor technique used for measuring real-time flux of analytes. This paper demonstrates the use of optical Microsensors for non-invasively measuring rhizosphere oxygen flux associated with respiration in plant roots, as well as boundary layer oxygen flux in phytoplankton mats. Highly sensitive/selective optrodes had little to no hysteresis/calibration drift during experimentation, and an extremely high signal-to-noise ratio. We have used this new tool to compare various aspects of rhizosphere oxygen flux for roots of Glycine max, Zea mays, and Phaseolus vulgaris, and also mapped developmentally relevant profiles and distinct temporal patterns. We also characterized real-time respiratory patterns during inhibition of cytochrome and alternative oxidase pathways via pharmacology. Boundary layer oxygen flux was also measured for a phytoplankton mat during dark:light cycling and exposure to pharamacological inhibitors. This highly sensitive technology enables non-invasive study of oxygen transport in plant systems under physiologically relevant conditions.
Seong Hwan Cho - One of the best experts on this subject based on the ideXlab platform.
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Power aware wireless Microsensor systems
European Solid-State Device Research Conference, 2002Co-Authors: Anantha P Chandrakasan, Rex Min, Seong Hwan Cho, Manish Bhardwaj, Alice WangAbstract:Distributed networks of thousands of collaborating Microsensors promise a maintenance-free, fault-tolerant platform for gathering rich, multi-dimensional observations of the environment. As a Microsensor node must operate for years on a tiny energy source, innovative energy management techniques are needed. Widespread device deployment makes battery replacement infeasible, requiring energy to be scavenged from the environment-- e.g., conversion of ambient vibrations to electric energy. Computation and communication must be optimized for very low duty cycles, making issues such as standby leakage and start-up overhead critical. All levels of the communication hierarchy, from the physical and link layer to routing protocols, must be tuned for energy efficiency. A total-system approach is required for reliable, self-powered Microsensor networks that deliver maximal system lifetime in the most challenging environments.
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energy efficient modulation and mac for asymmetric rf Microsensor systems
International Symposium on Low Power Electronics and Design, 2001Co-Authors: Andrew H J Wang, Seong Hwan Cho, Charles G Sodini, Anantha P ChandrakasanAbstract:Wireless Microsensor systems are used in a variety of civil and military applications. Such Microsensors are required to operate for years from a small energy source. To minimize the energy dissipation of the sensor node, RF front-end circuitry must be designed based on system level optimization of the entire network. This paper presents several energy minimization techniques derived from the unique properties of a practical short range asymmetric Microsensor system. These include energy efficient modulation schemes, appropriate multiple access protocols, and a fast turn-on transmitter architecture.
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physical layer driven protocol and algorithm design for energy efficient wireless sensor networks
ACM IEEE International Conference on Mobile Computing and Networking, 2001Co-Authors: Eugene Shih, Rex Min, Seong Hwan Cho, Alice Wang, Nathan Ickes, A Sinha, Anantha P ChandrakasanAbstract:The potential for collaborative, robust networks of Microsensors has attracted a great deal of research attention. For the most part, this is due to the compelling applications that will be enabled once wireless Microsensor networks are in place; location-sensing, environmental sensing, medical monitoring and similar applications are all gaining interest. However, wireless Microsensor networks pose numerous design challenges. For applications requiring long-term, robust sensing, such as military reconnaissance, one important challenge is to design sensor networks that have long system lifetimes. This challenge is especially difficult due to the energy-constrained nature of the devices. In order to design networks that have extremely long lifetimes, we propose a physical layer driven approach to designing protocols and algorithms. We first present a hardware model for our wireless sensor node and then introduce the design of physical layer aware protocols, algorithms, and applications that minimize energy consumption of the system. Our approach prescribes methods that can be used at all levels of the hierarchy to take advantage of the underlying hardware. We also show how to reduce energy consumption of non-ideal hardware through physical layer aware algorithms and protocols.
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energy efficient protocols for low duty cycle wireless Microsensor networks
International Conference on Acoustics Speech and Signal Processing, 2001Co-Authors: Seong Hwan Cho, Anantha P ChandrakasanAbstract:Emerging distributed wireless Microsensor networks will enable the reliable and fault tolerant monitoring of the environment. Such Microsensors are required to operate for years from a small energy source, while maintaining a reliable communication link to the base station. The design of energy-aware communication protocols can have a dramatic impact on the network lifetime for such applications. A detailed communication energy model, obtained from measurements, is introduced that incorporates the non-ideal behavior of the physical layer electronics. This includes the start-up energy cost of the RF transceiver, which dominates energy dissipation for short packet sizes. Using this model, various communication layer protocols are explored for asymmetrical sensor networks such as machine monitoring. The paper also proposes the use of a variable bandwidth allocation scheme that exploits spatial distribution of sensors.
Raluca-ioana Stefan-van Staden - One of the best experts on this subject based on the ideXlab platform.
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Stochastic Microsensors for the assessment of DNA damage in cancer
Analytical biochemistry, 2020Co-Authors: Raluca-ioana Stefan-van Staden, Liliana-roxana Balahura, Catalina Cioates-negut, Hassan Y. Aboul-eneinAbstract:Three stochastic Microsensors based on graphite powder modified with three different oleamides: N-(2-piperidin-1-ylethyl)oleamide, N-(3,4-dihydroxyphenethyl)oleamide and N-(2-morpholinoethyl)oleamide, were designed, characterized, and used to assess DNA damage in cancer by assaying two biomarkers namely 8-nitroguanine and 8-hydroxy-2'-deoxyguanosine. The two biomarkers were determined from urine and whole blood samples. The characterization of the Microsensors was done at two pHs 7.40 and 3.00. The best Microsensor for the simultaneous determination of biomarkers in whole blood and urine samples was the one based on the graphite paste modified with N-(3,4-dihydroxyphenethyl)oleamide. The results indicated that the proposed Microsensors can be reliably used for pattern recognition and quantitative determination of 8-nitroguanine and 8-hydroxy-2'-deoxyguanosine in whole blood and urine, and accordingly, for the assessment of DNA damage in cancer patients.
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New stochastic Microsensors based on oleamides
Electrochemistry Communications, 2015Co-Authors: Catalina Cioates Negut, Raluca-ioana Stefan-van Staden, Iuliana Moldoveanu, Eleonora-mihaela Ungureanu, Camelia Stanciu-gavanAbstract:Abstract Six oleamides: oleoylethanolamide, (Z)-N-[(1S)-2-hydroxy-1-(phenylmethyl)ethyl]-9octadecenamide, N-phenethyloleamide, N-[2-(4-methoxyphenyl)ethyl]oleamide, N-[1]naphthyloleamide, N-cyclohexyloleamide were synthesized and used as modifiers for the design of new stochastic Microsensors based on graphite paste. Carcinoembryonic antigen (CEA) was used as a model analyte to prove the stochastic behavior of the Microsensors. CEA was determined directly from whole blood samples with recoveries higher than 94.00%, favorizing pattern recognition of CEA in whole blood samples. The most sensitive stochastic Microsensor was the one based on the physical immobilization of N-[2-(4-methoxyphenyl)ethyl]oleamide in graphite paste.
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New stochastic Microsensors based on oleamides
Elsevier, 2015Co-Authors: Catalina Cioates Negut, Raluca-ioana Stefan-van Staden, Iuliana Moldoveanu, Eleonora-mihaela Ungureanu, Camelia Stanciu-gavanAbstract:Six oleamides: oleoylethanolamide, (Z)-N-[(1S)-2-hydroxy-1-(phenylmethyl)ethyl]-9octadecenamide, N-phenethyloleamide, N-[2-(4-methoxyphenyl)ethyl]oleamide, N-[1]naphthyloleamide, N-cyclohexyloleamide were synthesized and used as modifiers for the design of new stochastic Microsensors based on graphite paste. Carcinoembryonic antigen (CEA) was used as a model analyte to prove the stochastic behavior of the Microsensors. CEA was determined directly from whole blood samples with recoveries higher than 94.00%, favorizing pattern recognition of CEA in whole blood samples. The most sensitive stochastic Microsensor was the one based on the physical immobilization of N-[2-(4-methoxyphenyl)ethyl]oleamide in graphite paste. Keywords: Oleamides, Stochastic sensors, Carcinoembryonic antigen, Pattern recognitio
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Stochastic Microsensors as screening tools for neuron specific enolase
RSC Adv., 2014Co-Authors: Raluca-ioana Stefan-van Staden, Ionela Raluca Comnea, Jacobus F. Van Staden, Camelia Stanciu GavanAbstract:Stochastic Microsensors based on nanostructured materials from the classes of porphyrins and cyclodextrins, and carbon onions were used for new screening tools of whole blood samples for neuron specific enolase, a lung cancer biomarker. The neuron specific enolase was identified in a whole blood sample based on its signature (toff value). The best response was given by the Microsensor based on the complex of Mn(III) with 5,10,15,20-tetraphenyl-21H,23H-porphyrin, that exhibited a linear concentration range between 476.75 pg mL−1 and 7.628 ng mL−1, with a lowest determination limit of 51.74 pg mL−1. The proposed stochastic Microsensors provide a fast, sensitive, reliable and lower cost assay for the screening of neuron specific enolase from whole blood samples, without any pretreatment of whole blood samples.
Kimberly K Buhman - One of the best experts on this subject based on the ideXlab platform.
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a self referencing platinum nanoparticle decorated enzyme based microbiosensor for real time measurement of physiological glucose transport
Biosensors and Bioelectronics, 2011Co-Authors: Eric S Mclamore, Margaret Katherine Banks, David Benjamin Jaroch, Jin Shi, Jonathan C Claussen, A Uchida, Yan Jiang, Wen Zhang, Shawn S Donkin, Kimberly K BuhmanAbstract:Glucose is the central molecule in many biochemical pathways, and numerous approaches have been developed for fabricating micro biosensors designed to measure glucose concentration in/near cells and/or tissues. An inherent problem for Microsensors used in physiological studies is a low signal-to-noise ratio, which is further complicated by concentration drift due to the metabolic activity of cells. A Microsensor technique designed to filter extraneous electrical noise and provide direct quantification of active membrane transport is known as self-referencing. Self-referencing involves oscillation of a single Microsensor via computer-controlled stepper motors within a stable gradient formed near cells/tissues (i.e., within the concentration boundary layer). The non-invasive technique provides direct measurement of trans-membrane (or trans-tissue) analyte flux. A glucose micro biosensor was fabricated using deposition of nanomaterials (platinum black, multiwalled carbon nanotubes, Nafion) and glucose oxidase on a platinum/iridium microelectrode. The highly sensitive/selective biosensor was used in the self-referencing modality for cell/tissue physiological transport studies. Detailed analysis of signal drift/noise filtering via phase sensitive detection (including a post-measurement analytical technique) are provided. Using this highly sensitive technique, physiological glucose uptake is demonstrated in a wide range of metabolic and pharmacological studies. Use of this technique is demonstrated for cancer cell physiology, bioenergetics, diabetes, and microbial biofilm physiology. This robust and versatile biosensor technique will provide much insight into biological transport in biomedical, environmental, and agricultural research applications.