Wiliam Kaiser - Profile on Academia.edu (original) (raw)
Papers by Wiliam Kaiser
Proceedings of the 1997 international symposium on Low power electronics and design - ISLPED '97, 1997
Low power signal processing systems are required for distributed network microsensor technology. ... more Low power signal processing systems are required for distributed network microsensor technology. Network microsensors now provide a new monitoring and control capability for civil and military applications in transportation, manufacturing, biomedical technology, environmental management, and safety and security systems. Signal processing methods for event detection have been developed with low power, parallel architectures that optimize performance for unique sensor system requirements. Implementation of parallel datapatbs with shared arithmetic elements enables high throughput at low clock rate. This method has been used to implement a microsensor spectrum analyzer for a 200 sample/s measurement system. This 0.8p CMOS device operates with a 1M drain current at a 3V supply bias.
Proceedings. 10th IEEE International Workshop on Future Trends of Distributed Computing Systems, 2004. FTDCS 2004.
Distributed embedded sensor networks are now being successfully deployed in environmental monitor... more Distributed embedded sensor networks are now being successfully deployed in environmental monitoring of natural phenomena as well as for applications in commerce and physical security. Distributed architectures have been developed for cooperative detection, scalable data transport, and other capabilities and services. However, the complexity of environmental phenomena has introduced a new set of challenges related to sensing uncertainty associated with the unpredictable presence of obstacles to sensing that appear in the environment. These obstacles may dramatically reduce the effectiveness of distributed monitoring. Thus, a new distributed, embedded, computing attribute, self-awareness, must be developed and provided to distributed sensor systems. Selfawareness must provide the ability for a deployed system to autonomously detect and reduce its own sensing uncertainty. The physical constraints encountered by sensing require physical reconfiguration for detection and reduction of sensing uncertainty. Networked Infomechanical Systems (NIMS) consisting of distributed, embedded computing systems provides autonomous physical configuration through controlled mobility. The requirements that lead to NIMS, the implementation of NIMS technology, and its first applications are discussed here. .
2004 First Annual IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004.
A key challenge in sensor networks is ensuring the sustainability of the system at the required p... more A key challenge in sensor networks is ensuring the sustainability of the system at the required performance level, in an autonomous manner. Sustainability is a major concern becuase of severe resource constraints in terms of energy, bandwidth and sensing capabilities in the system. In this paper, we envision the use of a new design dimension to enhance sustainability of in sensor networks-the use of controlled mobility. We argue that this capability can alleviate resource limitations and improve system performance by adapting to deployment demands. While opportunistic use of external mobility has been considered before, the use of controlled mobility is largely unexplored. We also outline the research issues associated with effectively utilizing this new design dimension. Two system prototypes are described to present first steps towards realizing the proposed vision.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Advancement in wireless health sensor systems has triggered rapidly expanding research in continu... more Advancement in wireless health sensor systems has triggered rapidly expanding research in continuous activity monitoring for chronic disease management or promotion and assessment of physical rehabilitation. Wireless motion sensing is increasingly important in treatments where remote collection of sensor measurements can provide an in-field objective evaluation of physical activity patterns. The well-known challenge of limited operating lifetime of energy-constrained wireless health sensor systems continues to present a primary limitation for these applications. This paper introduces CARER, a software system that supports a novel algorithm that exploits knowledge of context and dynamically schedules sensor measurement episodes within an energy consumption budget while ensuring classification accuracy. The sensor selection algorithm in the CARER system is based on Partially Observable Markov Decision Process (POMDP). The parameters for the POMDP algorithm can be obtained through stan...
Presettable micromachined MEMS accelerometers
Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291), 1999
Rapidly emerging wireless distributed sensing applications such as seismic monitoring, civil stru... more Rapidly emerging wireless distributed sensing applications such as seismic monitoring, civil structural safety, security, and military threat identification require small, inexpensive acceleration sensors with sensitivities limited by the background noise of the earth. As will be shown, this goal may only be attained through a low resonant frequency device with a presettable spring. This paper will discuss design techniques in the quest for this goal and a novel, mechanically micro-adjustable Z-axis deep reactive ion etched (DRIE) accelerometer sensor with a resonant frequency below 100 Hz. This accelerometer design will be capable of sub-micro-g sensitivities and has a simple, low cost fabrication process
A modular low-energy wireless sensing and processing platform with an open software framework for unattended ground sensor applications
Unattended/Unmanned Ground, Ocean, and Air Sensor Technologies and Applications VI, 2004
A low-power hardware platform and a software framework to support distributed wireless sensing fo... more A low-power hardware platform and a software framework to support distributed wireless sensing for unattended ground sensor (UGS) applications has been developed. This platform provides a comprehensive set of hardware capabilities needed to meet the sensing, processing, and communication requirements for UGS, including a 16-channel analog interface, a processor dedicated to managing real-time requirements, dual wireless interfaces, and a low-power system bus to enable system modularity. An open software framework based on the Linux kernel is hosted on the main system processor. This framework incorporates the tools for effectively utilizing the capabilities of the hardware platform and rapidly developing applications in a networked, embedded environment.
A wireless biomedical instrument for evidence-based tissue wound characterization
Wireless Health 2010, 2010
Patients' skin integrity has long been an issue of concern in nursing homes and ... more Patients' skin integrity has long been an issue of concern in nursing homes and hospitals. Overall incidence of pressure ulcers for hospitalized patients is as high as 50%. The estimated cost of treating pressure ulcers ranges from 5,000to5,000 to 5,000to40,000 for each ulcer, depending on severity. A smart compact capacitive sensing wireless handheld system is presented which measures Sub-Epidermal Moisture (SEM) as a mean to detect and monitor early symptoms of ulcer development. The system was successfully verified in trials with 30 volunteers and is currently deployed for clinical trials in four nursing homes.
Proceedings 2007 IEEE International Conference on Robotics and Automation, 2007
Distributed, high-density spatiotemporal observations are proposed for answering many river-relat... more Distributed, high-density spatiotemporal observations are proposed for answering many river-related questions, including those pertaining to hydraulics and multi-dimensional river modeling, geomorphology, sediment transport and riparian habitat restoration. We present here a case study of an autonomous, high-resolution robotic spatial mapping of cross-sectional velocity and salt concentration in a river basin. Several experiments for analyzing the spatial and temporal trends at multiple cross-sections of the San Joaquin River were performed during the campaign from August 21-25, 2006. Preliminary analysis from these experiments illustrating the range of investigations is presented. Lessons learned during the campaign are discussed to provide useful insights for similar robotic investigations in aquatic environments.
RAGOBOT: A New Platform for Wireless Mobile Sensor Networks
Lecture Notes in Computer Science, 2005
To explore mobility in wireless sensor networks, we created Ragobot, a small-sized robot platform... more To explore mobility in wireless sensor networks, we created Ragobot, a small-sized robot platform that provides a large number of features, some not sup-ported even by larger-size robots. At only 13.3 cm long by 6cm wide, Ragobot is positioned at the intersection of size and ...
Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization, 2006
This demonstration will present a radio testbed that is being used to characterize the quality of... more This demonstration will present a radio testbed that is being used to characterize the quality of directional peer-to-peer wireless communications in wilderness environments.
2010 IEEE International Conference on Robotics and Automation, 2010
The need for efficient monitoring of spatiotemporal dynamics in large environmental surveillance ... more The need for efficient monitoring of spatiotemporal dynamics in large environmental surveillance applications motivates the use of robotic sensors to achieve sufficient spatial and temporal coverage. A common approach in machine learning to model spatial dynamics is to use the nonparametric Bayesian framework known as Gaussian Processes (GPs) (c.f., [1]) which are fully specified by a mean and a covariance function. However, defining suitable covariance functions that are able to appropriately model complex spacetime dependencies in the environment is a challenging task. In this paper, we develop a generic approach for constructing several classes of covariance functions for spatio-temporal GP modeling. The GP models are then extended to perform efficient path planning in continuous space while maximizing the information gain. Extensive empirical evaluation for the different classes of covariance functions using real world sensing datasets is discussed, including experiments on a tethered robotic system-Networked Info Mechanical System (NIMS).
Proceedings of the 3rd international symposium on Information processing in sensor networks, 2004
The performance of a sensor network may be best judged by the quality of application specific inf... more The performance of a sensor network may be best judged by the quality of application specific information return. The actual sensing performance of a deployed sensor network depends on several factors which cannot be accounted at design time, such as environmental obstacles to sensing. We propose the use of mobility to overcome the effect of unpredictable environmental influence and to adapt to run time dynamics. Now, mobility with its dependencies such as precise localization and navigation is expensive in terms of hardware resources and energy constraints, and may not be feasible in compact, densely deployed and widespread sensor nodes. We present a method based on low complexity and low energy actuation primitives which are feasible for implementation in sensor networks. We prove how these primitives improve the detection capabilities with theoretical analysis, extensive simulations and real world experiments. The significant coverage advantage recurrent in our investigation justifies our own and other parallel ongoing work in the implementation and refinement of self-actuated systems.
A wireless biomedical handheld instrument for evidence-based detection of pressure ulcers
Proceedings of the 2nd Conference on Wireless Health, 2011
Pressure Ulcer (PU) incidence leads to considerable risk, in particular for the frail elderly, an... more Pressure Ulcer (PU) incidence leads to considerable risk, in particular for the frail elderly, and a large national healthcare treatment cost. Evidence-based methods for assuring the health and safety of patients are urgently needed. Recent clinical trials have demonstrated that sub-epidermal moisture (SEM) present in tissue may be measured by interrogation of tissue dielectric properties and are associated with the
Demonstration of WHI-FIT
Wireless Health 2010, 2010
Physical rehabilitation has become increasingly important for subjects recovering from treatment ... more Physical rehabilitation has become increasingly important for subjects recovering from treatment in clinics and from disease conditions including stroke [6]. A particularly critical requirement is the support of individuals who suffer from impaired mobility or may be confined to beds, yet must be provided with an assured fitness promotion regimen. We will demonstrate a portable cycle restorator that continuously measures
Silicon bulk micromachined vibratory gyroscope for microspacecraft
SPIE Proceedings, 1996
This paper reports on the design, modeling, fabrication, and characterization of a novel silicon ... more This paper reports on the design, modeling, fabrication, and characterization of a novel silicon bulk micromachined vibratory rate gyroscope and a 3-axes rotation sensing system using this new type of.
Proceedings of the 2nd Conference on Wireless Health, 2011
Continued rapid progress in the development of embedded motion sensing enables wearable devices t... more Continued rapid progress in the development of embedded motion sensing enables wearable devices that provide fundamental advances in the capability to monitor and classify human motion, detect movement disorders, and estimate energy expenditure. With this progress, it is becoming possible to provide, for the first time, evaluation of outcomes of rehabilitation interventions and direct guidance for advancement of subject health, wellness, and safety. The progress in motion classification relies on both the performance of new sensor fusion methods that provide inference, and the energy efficiency of energy-constrained monitoring sensors. As will be described here, both of these objectives require advances in the capability of detecting and classifying the location and environmental context. Context directly enables both enhanced motion classification accuracy and speed through reduction in search space, and reduced energy demand through context-aware optimization of sensor sampling and operation schedules. There have been attempts to introduce context awareness into activity monitoring with limited success, due to the ambiguity in the definition of context, and the lack of a system architecture that enables the adaptation of signal processing and sensor fusion algorithms specific to the task of personalized activity monitoring. In this paper we present a novel end-to-end system that provides context guided personalized activity classification. With a refined concept of context, the system introduces interface models that feature a unique context classification committee, the concept of context specific activity classification, the ability to manage sensors given context, and the ability to operate in real time through web services. We also present an implementation that demonstrates accurate context classification, accurate activity classification using context specific models with improved accuracy and speed, and extended operating life through sensor energy management.
Context-aware Sensing of Physiological Signals
2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
Visualization and quantification of T cell–mediated cytotoxicity using cell-permeable fluorogenic caspase substrates
Nature Medicine, 2002
We have developed a non-radioactive flow-cytometry assay to monitor and quantify the target-cell ... more We have developed a non-radioactive flow-cytometry assay to monitor and quantify the target-cell killing activities mediated by cytotoxic T lymphocytes (CTLs). This flow-cytometry CTL (FCC) assay is predicated on measurement of CTL-induced caspase activation in target cells through detection of the specific cleavage of fluorogenic caspase substrates. Here we show that this assay reliably detects antigen-specific CTL killing of target cells, and demonstrate that it provides a more sensitive, more informative and safer alternative to the standard 51Cr-release assay most often used to quantify CTL responses. The FCC assay can be used to study CTL-mediated killing of primary host target cells of different cell lineages, and enables the study of antigen-specific cellular immune responses in real time at the single-cell level. As such, the FCC assay can provide a valuable tool for studies of infectious disease pathogenesis and development of new vaccines and immunotherapies.
Limnology and Oceanography, 2008
A wireless network of buoys, two autonomous robotic boats, and an autonomous tethered vertical pr... more A wireless network of buoys, two autonomous robotic boats, and an autonomous tethered vertical profiling system were used to characterize phytoplankton dynamics and spatiotemporal changes in chemical and physical forcing factors in a small montane lake (Lake Fulmor, Idyllwild, California). Three deployments each year were conducted in 2005 and 2006 to examine seasonal changes in the structure of the lake and phytoplankton assemblage, as well as fine-scale temporal and spatial variations. The buoys yielded fine-scale temporal patterns of in situ fluorescence and temperature, while the vertical profiling system yielded two-dimensional, cross-sectional profiles of several parameters. The autonomous vehicles provided information on fluorescence and corresponding temperature patterns across the surface of the lake. Average, lake-wide chlorophyll concentrations increased 10fold seasonally, and strong anoxia developed in the hypolimnion during the summer. The latter process dramatically affected vertical chemical gradients in the 5 m water column of the lake. Small-scale spatial (,1 m) and temporal (minutes) heterogeneity in fluorescence were surprisingly large. These variations were due predominantly to vertical mixing of the phytoplankton assemblage and to phytoplankton vertical migratory behavior. Large peaks in fluorescence at 0.5-m occurred at very short time intervals (minutes) during all deployments, and appeared to be due to upward mixing of deeper dwelling eukaryotic phytoplankton during early-midsummer , or downward mixing of surface-associated cyanobacteria during late summer.
Journal of Field Robotics, 2007
Large‐scale environmental sensing, e.g., understanding microbial processes in an aquatic ecosyste... more Large‐scale environmental sensing, e.g., understanding microbial processes in an aquatic ecosystem, requires coordination across a multidisciplinary team of experts working closely with a robotic sensing and sampling system. We describe a human‐robot team that conducted an aquatic sampling campaign in Lake Fulmor, San Jacinto Mountains Reserve, California during three consecutive site visits (May 9–11, June 19–22, and August 28–31, 2006). The goal of the campaign was to study the behavior of phytoplankton in the lake and their relationship to the underlying physical, chemical, and biological parameters. Phytoplankton form the largest source of oxygen and the foundation of the food web in most aquatic ecosystems. The reported campaign consisted of three system deployments spanning four months. The robotic system consisted of two subsystems—NAMOS (networked aquatic microbial observing systems) comprised of a robotic boat and static buoys, and NIMS‐RD (rapidly deployable networked info...
Proceedings of the 1997 international symposium on Low power electronics and design - ISLPED '97, 1997
Low power signal processing systems are required for distributed network microsensor technology. ... more Low power signal processing systems are required for distributed network microsensor technology. Network microsensors now provide a new monitoring and control capability for civil and military applications in transportation, manufacturing, biomedical technology, environmental management, and safety and security systems. Signal processing methods for event detection have been developed with low power, parallel architectures that optimize performance for unique sensor system requirements. Implementation of parallel datapatbs with shared arithmetic elements enables high throughput at low clock rate. This method has been used to implement a microsensor spectrum analyzer for a 200 sample/s measurement system. This 0.8p CMOS device operates with a 1M drain current at a 3V supply bias.
Proceedings. 10th IEEE International Workshop on Future Trends of Distributed Computing Systems, 2004. FTDCS 2004.
Distributed embedded sensor networks are now being successfully deployed in environmental monitor... more Distributed embedded sensor networks are now being successfully deployed in environmental monitoring of natural phenomena as well as for applications in commerce and physical security. Distributed architectures have been developed for cooperative detection, scalable data transport, and other capabilities and services. However, the complexity of environmental phenomena has introduced a new set of challenges related to sensing uncertainty associated with the unpredictable presence of obstacles to sensing that appear in the environment. These obstacles may dramatically reduce the effectiveness of distributed monitoring. Thus, a new distributed, embedded, computing attribute, self-awareness, must be developed and provided to distributed sensor systems. Selfawareness must provide the ability for a deployed system to autonomously detect and reduce its own sensing uncertainty. The physical constraints encountered by sensing require physical reconfiguration for detection and reduction of sensing uncertainty. Networked Infomechanical Systems (NIMS) consisting of distributed, embedded computing systems provides autonomous physical configuration through controlled mobility. The requirements that lead to NIMS, the implementation of NIMS technology, and its first applications are discussed here. .
2004 First Annual IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004.
A key challenge in sensor networks is ensuring the sustainability of the system at the required p... more A key challenge in sensor networks is ensuring the sustainability of the system at the required performance level, in an autonomous manner. Sustainability is a major concern becuase of severe resource constraints in terms of energy, bandwidth and sensing capabilities in the system. In this paper, we envision the use of a new design dimension to enhance sustainability of in sensor networks-the use of controlled mobility. We argue that this capability can alleviate resource limitations and improve system performance by adapting to deployment demands. While opportunistic use of external mobility has been considered before, the use of controlled mobility is largely unexplored. We also outline the research issues associated with effectively utilizing this new design dimension. Two system prototypes are described to present first steps towards realizing the proposed vision.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011
Advancement in wireless health sensor systems has triggered rapidly expanding research in continu... more Advancement in wireless health sensor systems has triggered rapidly expanding research in continuous activity monitoring for chronic disease management or promotion and assessment of physical rehabilitation. Wireless motion sensing is increasingly important in treatments where remote collection of sensor measurements can provide an in-field objective evaluation of physical activity patterns. The well-known challenge of limited operating lifetime of energy-constrained wireless health sensor systems continues to present a primary limitation for these applications. This paper introduces CARER, a software system that supports a novel algorithm that exploits knowledge of context and dynamically schedules sensor measurement episodes within an energy consumption budget while ensuring classification accuracy. The sensor selection algorithm in the CARER system is based on Partially Observable Markov Decision Process (POMDP). The parameters for the POMDP algorithm can be obtained through stan...
Presettable micromachined MEMS accelerometers
Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291), 1999
Rapidly emerging wireless distributed sensing applications such as seismic monitoring, civil stru... more Rapidly emerging wireless distributed sensing applications such as seismic monitoring, civil structural safety, security, and military threat identification require small, inexpensive acceleration sensors with sensitivities limited by the background noise of the earth. As will be shown, this goal may only be attained through a low resonant frequency device with a presettable spring. This paper will discuss design techniques in the quest for this goal and a novel, mechanically micro-adjustable Z-axis deep reactive ion etched (DRIE) accelerometer sensor with a resonant frequency below 100 Hz. This accelerometer design will be capable of sub-micro-g sensitivities and has a simple, low cost fabrication process
A modular low-energy wireless sensing and processing platform with an open software framework for unattended ground sensor applications
Unattended/Unmanned Ground, Ocean, and Air Sensor Technologies and Applications VI, 2004
A low-power hardware platform and a software framework to support distributed wireless sensing fo... more A low-power hardware platform and a software framework to support distributed wireless sensing for unattended ground sensor (UGS) applications has been developed. This platform provides a comprehensive set of hardware capabilities needed to meet the sensing, processing, and communication requirements for UGS, including a 16-channel analog interface, a processor dedicated to managing real-time requirements, dual wireless interfaces, and a low-power system bus to enable system modularity. An open software framework based on the Linux kernel is hosted on the main system processor. This framework incorporates the tools for effectively utilizing the capabilities of the hardware platform and rapidly developing applications in a networked, embedded environment.
A wireless biomedical instrument for evidence-based tissue wound characterization
Wireless Health 2010, 2010
Patients' skin integrity has long been an issue of concern in nursing homes and ... more Patients' skin integrity has long been an issue of concern in nursing homes and hospitals. Overall incidence of pressure ulcers for hospitalized patients is as high as 50%. The estimated cost of treating pressure ulcers ranges from 5,000to5,000 to 5,000to40,000 for each ulcer, depending on severity. A smart compact capacitive sensing wireless handheld system is presented which measures Sub-Epidermal Moisture (SEM) as a mean to detect and monitor early symptoms of ulcer development. The system was successfully verified in trials with 30 volunteers and is currently deployed for clinical trials in four nursing homes.
Proceedings 2007 IEEE International Conference on Robotics and Automation, 2007
Distributed, high-density spatiotemporal observations are proposed for answering many river-relat... more Distributed, high-density spatiotemporal observations are proposed for answering many river-related questions, including those pertaining to hydraulics and multi-dimensional river modeling, geomorphology, sediment transport and riparian habitat restoration. We present here a case study of an autonomous, high-resolution robotic spatial mapping of cross-sectional velocity and salt concentration in a river basin. Several experiments for analyzing the spatial and temporal trends at multiple cross-sections of the San Joaquin River were performed during the campaign from August 21-25, 2006. Preliminary analysis from these experiments illustrating the range of investigations is presented. Lessons learned during the campaign are discussed to provide useful insights for similar robotic investigations in aquatic environments.
RAGOBOT: A New Platform for Wireless Mobile Sensor Networks
Lecture Notes in Computer Science, 2005
To explore mobility in wireless sensor networks, we created Ragobot, a small-sized robot platform... more To explore mobility in wireless sensor networks, we created Ragobot, a small-sized robot platform that provides a large number of features, some not sup-ported even by larger-size robots. At only 13.3 cm long by 6cm wide, Ragobot is positioned at the intersection of size and ...
Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization, 2006
This demonstration will present a radio testbed that is being used to characterize the quality of... more This demonstration will present a radio testbed that is being used to characterize the quality of directional peer-to-peer wireless communications in wilderness environments.
2010 IEEE International Conference on Robotics and Automation, 2010
The need for efficient monitoring of spatiotemporal dynamics in large environmental surveillance ... more The need for efficient monitoring of spatiotemporal dynamics in large environmental surveillance applications motivates the use of robotic sensors to achieve sufficient spatial and temporal coverage. A common approach in machine learning to model spatial dynamics is to use the nonparametric Bayesian framework known as Gaussian Processes (GPs) (c.f., [1]) which are fully specified by a mean and a covariance function. However, defining suitable covariance functions that are able to appropriately model complex spacetime dependencies in the environment is a challenging task. In this paper, we develop a generic approach for constructing several classes of covariance functions for spatio-temporal GP modeling. The GP models are then extended to perform efficient path planning in continuous space while maximizing the information gain. Extensive empirical evaluation for the different classes of covariance functions using real world sensing datasets is discussed, including experiments on a tethered robotic system-Networked Info Mechanical System (NIMS).
Proceedings of the 3rd international symposium on Information processing in sensor networks, 2004
The performance of a sensor network may be best judged by the quality of application specific inf... more The performance of a sensor network may be best judged by the quality of application specific information return. The actual sensing performance of a deployed sensor network depends on several factors which cannot be accounted at design time, such as environmental obstacles to sensing. We propose the use of mobility to overcome the effect of unpredictable environmental influence and to adapt to run time dynamics. Now, mobility with its dependencies such as precise localization and navigation is expensive in terms of hardware resources and energy constraints, and may not be feasible in compact, densely deployed and widespread sensor nodes. We present a method based on low complexity and low energy actuation primitives which are feasible for implementation in sensor networks. We prove how these primitives improve the detection capabilities with theoretical analysis, extensive simulations and real world experiments. The significant coverage advantage recurrent in our investigation justifies our own and other parallel ongoing work in the implementation and refinement of self-actuated systems.
A wireless biomedical handheld instrument for evidence-based detection of pressure ulcers
Proceedings of the 2nd Conference on Wireless Health, 2011
Pressure Ulcer (PU) incidence leads to considerable risk, in particular for the frail elderly, an... more Pressure Ulcer (PU) incidence leads to considerable risk, in particular for the frail elderly, and a large national healthcare treatment cost. Evidence-based methods for assuring the health and safety of patients are urgently needed. Recent clinical trials have demonstrated that sub-epidermal moisture (SEM) present in tissue may be measured by interrogation of tissue dielectric properties and are associated with the
Demonstration of WHI-FIT
Wireless Health 2010, 2010
Physical rehabilitation has become increasingly important for subjects recovering from treatment ... more Physical rehabilitation has become increasingly important for subjects recovering from treatment in clinics and from disease conditions including stroke [6]. A particularly critical requirement is the support of individuals who suffer from impaired mobility or may be confined to beds, yet must be provided with an assured fitness promotion regimen. We will demonstrate a portable cycle restorator that continuously measures
Silicon bulk micromachined vibratory gyroscope for microspacecraft
SPIE Proceedings, 1996
This paper reports on the design, modeling, fabrication, and characterization of a novel silicon ... more This paper reports on the design, modeling, fabrication, and characterization of a novel silicon bulk micromachined vibratory rate gyroscope and a 3-axes rotation sensing system using this new type of.
Proceedings of the 2nd Conference on Wireless Health, 2011
Continued rapid progress in the development of embedded motion sensing enables wearable devices t... more Continued rapid progress in the development of embedded motion sensing enables wearable devices that provide fundamental advances in the capability to monitor and classify human motion, detect movement disorders, and estimate energy expenditure. With this progress, it is becoming possible to provide, for the first time, evaluation of outcomes of rehabilitation interventions and direct guidance for advancement of subject health, wellness, and safety. The progress in motion classification relies on both the performance of new sensor fusion methods that provide inference, and the energy efficiency of energy-constrained monitoring sensors. As will be described here, both of these objectives require advances in the capability of detecting and classifying the location and environmental context. Context directly enables both enhanced motion classification accuracy and speed through reduction in search space, and reduced energy demand through context-aware optimization of sensor sampling and operation schedules. There have been attempts to introduce context awareness into activity monitoring with limited success, due to the ambiguity in the definition of context, and the lack of a system architecture that enables the adaptation of signal processing and sensor fusion algorithms specific to the task of personalized activity monitoring. In this paper we present a novel end-to-end system that provides context guided personalized activity classification. With a refined concept of context, the system introduces interface models that feature a unique context classification committee, the concept of context specific activity classification, the ability to manage sensors given context, and the ability to operate in real time through web services. We also present an implementation that demonstrates accurate context classification, accurate activity classification using context specific models with improved accuracy and speed, and extended operating life through sensor energy management.
Context-aware Sensing of Physiological Signals
2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2007
Visualization and quantification of T cell–mediated cytotoxicity using cell-permeable fluorogenic caspase substrates
Nature Medicine, 2002
We have developed a non-radioactive flow-cytometry assay to monitor and quantify the target-cell ... more We have developed a non-radioactive flow-cytometry assay to monitor and quantify the target-cell killing activities mediated by cytotoxic T lymphocytes (CTLs). This flow-cytometry CTL (FCC) assay is predicated on measurement of CTL-induced caspase activation in target cells through detection of the specific cleavage of fluorogenic caspase substrates. Here we show that this assay reliably detects antigen-specific CTL killing of target cells, and demonstrate that it provides a more sensitive, more informative and safer alternative to the standard 51Cr-release assay most often used to quantify CTL responses. The FCC assay can be used to study CTL-mediated killing of primary host target cells of different cell lineages, and enables the study of antigen-specific cellular immune responses in real time at the single-cell level. As such, the FCC assay can provide a valuable tool for studies of infectious disease pathogenesis and development of new vaccines and immunotherapies.
Limnology and Oceanography, 2008
A wireless network of buoys, two autonomous robotic boats, and an autonomous tethered vertical pr... more A wireless network of buoys, two autonomous robotic boats, and an autonomous tethered vertical profiling system were used to characterize phytoplankton dynamics and spatiotemporal changes in chemical and physical forcing factors in a small montane lake (Lake Fulmor, Idyllwild, California). Three deployments each year were conducted in 2005 and 2006 to examine seasonal changes in the structure of the lake and phytoplankton assemblage, as well as fine-scale temporal and spatial variations. The buoys yielded fine-scale temporal patterns of in situ fluorescence and temperature, while the vertical profiling system yielded two-dimensional, cross-sectional profiles of several parameters. The autonomous vehicles provided information on fluorescence and corresponding temperature patterns across the surface of the lake. Average, lake-wide chlorophyll concentrations increased 10fold seasonally, and strong anoxia developed in the hypolimnion during the summer. The latter process dramatically affected vertical chemical gradients in the 5 m water column of the lake. Small-scale spatial (,1 m) and temporal (minutes) heterogeneity in fluorescence were surprisingly large. These variations were due predominantly to vertical mixing of the phytoplankton assemblage and to phytoplankton vertical migratory behavior. Large peaks in fluorescence at 0.5-m occurred at very short time intervals (minutes) during all deployments, and appeared to be due to upward mixing of deeper dwelling eukaryotic phytoplankton during early-midsummer , or downward mixing of surface-associated cyanobacteria during late summer.
Journal of Field Robotics, 2007
Large‐scale environmental sensing, e.g., understanding microbial processes in an aquatic ecosyste... more Large‐scale environmental sensing, e.g., understanding microbial processes in an aquatic ecosystem, requires coordination across a multidisciplinary team of experts working closely with a robotic sensing and sampling system. We describe a human‐robot team that conducted an aquatic sampling campaign in Lake Fulmor, San Jacinto Mountains Reserve, California during three consecutive site visits (May 9–11, June 19–22, and August 28–31, 2006). The goal of the campaign was to study the behavior of phytoplankton in the lake and their relationship to the underlying physical, chemical, and biological parameters. Phytoplankton form the largest source of oxygen and the foundation of the food web in most aquatic ecosystems. The reported campaign consisted of three system deployments spanning four months. The robotic system consisted of two subsystems—NAMOS (networked aquatic microbial observing systems) comprised of a robotic boat and static buoys, and NIMS‐RD (rapidly deployable networked info...