The article describes the design of the Community Seismic Network, which is a dense open seismic ... more The article describes the design of the Community Seismic Network, which is a dense open seismic network based on low cost sensors. The inputs are from sensors hosted by volunteers from the community by direct connection to their personal computers, or through sensors built into mobile devices. The server is cloud-based for robustness and to dynamically handle the load of impulsive earthquake events. The main product of the network is a map of peak acceleration, delivered within seconds of the ground shaking. The lateral variations in the level of shaking will be valuable to first responders, and the waveform information from a dense network will allow detailed mapping of the rupture process. Sensors in buildings may be useful for monitoring the state-of-health of the structure after major shaking.
[1990] Proceedings. Workshop on the Management of Replicated Data
Ficus is a replicated general ling environment for Unix intended to scale to very large nationwid... more Ficus is a replicated general ling environment for Unix intended to scale to very large nationwide networks. The system employs an optimistic one copy a vailability" model in which con icting updates to the le system's directory information are automatically reconciled, while con icting le updates are reliably detected and reported. The system architecture is based on a stackable layers methodology which permits a high degree of modularity and extensibility of le system services. This paper presents the motivations for replication and summarizes the case for optimistic concurrency control for large scale distributed le systems. It presents a brief description of the Ficus le system and concludes with a number of outstanding issues which m ust be addressed.
Ficus is a exible replication facility with optimistic concurrency control designed to span a wid... more Ficus is a exible replication facility with optimistic concurrency control designed to span a wide range of scales and network environments. Support for partitioned o p eration is fundamental to the Ficus design but was not widely exercised in early Ficus use. This position paper reports recent experiences using Ficus in settings where some replicas are only occasionally connected to a network, and hence p artitioned o p eration is the rule rather than the exception. We conclude that with some tuning, Ficus adapted quite well to primarily disconnected o p eration.
BibTex@ misc {title={TER0: Overview Poster: Terrestrial Ecology Observing Systems at the James Re... more BibTex@ misc {title={TER0: Overview Poster: Terrestrial Ecology Observing Systems at the James Reserve}, author={Michael Hamilton, Eric Graham, Deborah Estrin, Phil Rundel, Michael Allen, Bill Kaiser, Bill Swenson, Michael Wimbrow, Michael Taggart, Vanessa ...
Hardware, Software, Systems • TEOS applications research group collaborates with many core CENS g... more Hardware, Software, Systems • TEOS applications research group collaborates with many core CENS groups to design, develop, deploy, evaluate, and support Embedded Networked Sensors (ENS) and instrumented platforms for ecological research. • Fixed and mobile arrays, instruments, and associated technologies for measurement are deployed, tested, and are being continually refined as the first wave of CENS systems at our James Reserve field site.
Abstract. Middleware layers placed between user clients and application servers have been used to... more Abstract. Middleware layers placed between user clients and application servers have been used to perform a variety of functions to support the vision of nomadic computing across varying platforms. In previous work we have used middleware to perform a new capability, application session handoff, using a single Middleware Server to provide all functionality. However, to improve the scalability of our architecture, we have designed an efficient distributed Middleware Service layer that properly maintains application session handoff semantics while being able to service a large number of clients. We show that this service layer improves the scalability of general client-to-application server interaction as well as the specific case of application session handoff. We detail protocols involved in performing handoff and analyse an implementation of the architecture that supports the use of a real medical teaching tool. From experimental results it can be seen that our Middleware Service e...
Handoff of Application Sessions Across Time and Space ... pa-per we address the issue of applicat... more Handoff of Application Sessions Across Time and Space ... pa-per we address the issue of application session transfer for unin-terrupted data access across this diverse ... From this effort we have established baseline performance metrics and have found that the overhead is within ...
The Community Seismic Network (CSN) has partnered with the NASA Jet Propulsion Laboratory (JPL) t... more The Community Seismic Network (CSN) has partnered with the NASA Jet Propulsion Laboratory (JPL) to initiate a campus-wide structural monitoring program of all buildings on the premises. The JPL campus serves as a proxy for a densely instrumented urban city with localized vibration measurements collected throughout the free-field and built environment. Instrumenting the entire campus provides dense measurements in a horizontal geospatial sense for soil response; in addition five buildings have been instrumented on every floor of the structure. Each building has a unique structural system as well as varied amounts of structural information via structural drawings, making several levels of assessment and evaluation possible. Computational studies with focus on damage detection applied to the campus structural network are demonstrated for a collection of buildings. For campus-wide real-time and post-event evaluation, ground and building response products using CSN data are illustrating ...
The Kluwer International Series in Engineering and Computer Science, 2000
Open architecture systems present many challenges for system and application designers. Problems ... more Open architecture systems present many challenges for system and application designers. Problems such as selecting adaptations, reliability, and security are overly complicated in traditional adaptation paradigms. Frequently, network applications operate peer to peer — where it is in the best interest of both parties to communicate. This model can be exploited to our benefit in open architectures. By shifting adaptation models towards co-operative adaptation along endpoints, hard problems can be simplified; at the same time, we can still maintain desired flexibility.
2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333), 2002
Ubiquitous computing across a variety of wired and wireless connections still lacks an effective ... more Ubiquitous computing across a variety of wired and wireless connections still lacks an effective security architecture. In our research work, we address the specific issue of designing and building a security architecture for Application Session Handoff, a functionality which we envision will be a key component enabling ubiquitous computing. Our architecture incorporates a number of proven approaches into the new context of ubiquitous computing. We employ the Bell-LaPadula and capability models to realise access control and adopt Public Key Infrastructure (PKI)-based approaches to provide efficient and authenticated end-to-end security. To demonstrate the effectiveness of our design, we implemented an application enabled with this security architecture and showed that it incurred low latency.
Previous distributed le systems have relied on either convention or obtaining dynamic global agre... more Previous distributed le systems have relied on either convention or obtaining dynamic global agreement t o p r o vide network transparent le naming. This paper argues that neither approach can succeed as systems scale to the kind of size that is anticipated in the current decade. We propose instead a novel name mapping scheme which relies on a fragmented, selectively replicated name translation database. Updates to the naming database are coordinated by an optimistic concurrency control strategy with automatic propagation and reconciliation. A prototype of the name mapping mechanism has been implemented and is in use in the Ficus replicated le system.
The Caltech CSN project collects sensor data from thousands of personal devices for real-time res... more The Caltech CSN project collects sensor data from thousands of personal devices for real-time response to dangerous earthquakes.
The article describes the design of the Community Seismic Network, which is a dense open seismic ... more The article describes the design of the Community Seismic Network, which is a dense open seismic network based on low cost sensors. The inputs are from sensors hosted by volunteers from the community by direct connection to their personal computers, or through sensors built into mobile devices. The server is cloud-based for robustness and to dynamically handle the load of impulsive earthquake events. The main product of the network is a map of peak acceleration, delivered within seconds of the ground shaking. The lateral variations in the level of shaking will be valuable to first responders, and the waveform information from a dense network will allow detailed mapping of the rupture process. Sensors in buildings may be useful for monitoring the state-of-health of the structure after major shaking.
[1990] Proceedings. Workshop on the Management of Replicated Data
Ficus is a replicated general ling environment for Unix intended to scale to very large nationwid... more Ficus is a replicated general ling environment for Unix intended to scale to very large nationwide networks. The system employs an optimistic one copy a vailability" model in which con icting updates to the le system's directory information are automatically reconciled, while con icting le updates are reliably detected and reported. The system architecture is based on a stackable layers methodology which permits a high degree of modularity and extensibility of le system services. This paper presents the motivations for replication and summarizes the case for optimistic concurrency control for large scale distributed le systems. It presents a brief description of the Ficus le system and concludes with a number of outstanding issues which m ust be addressed.
Ficus is a exible replication facility with optimistic concurrency control designed to span a wid... more Ficus is a exible replication facility with optimistic concurrency control designed to span a wide range of scales and network environments. Support for partitioned o p eration is fundamental to the Ficus design but was not widely exercised in early Ficus use. This position paper reports recent experiences using Ficus in settings where some replicas are only occasionally connected to a network, and hence p artitioned o p eration is the rule rather than the exception. We conclude that with some tuning, Ficus adapted quite well to primarily disconnected o p eration.
BibTex@ misc {title={TER0: Overview Poster: Terrestrial Ecology Observing Systems at the James Re... more BibTex@ misc {title={TER0: Overview Poster: Terrestrial Ecology Observing Systems at the James Reserve}, author={Michael Hamilton, Eric Graham, Deborah Estrin, Phil Rundel, Michael Allen, Bill Kaiser, Bill Swenson, Michael Wimbrow, Michael Taggart, Vanessa ...
Hardware, Software, Systems • TEOS applications research group collaborates with many core CENS g... more Hardware, Software, Systems • TEOS applications research group collaborates with many core CENS groups to design, develop, deploy, evaluate, and support Embedded Networked Sensors (ENS) and instrumented platforms for ecological research. • Fixed and mobile arrays, instruments, and associated technologies for measurement are deployed, tested, and are being continually refined as the first wave of CENS systems at our James Reserve field site.
Abstract. Middleware layers placed between user clients and application servers have been used to... more Abstract. Middleware layers placed between user clients and application servers have been used to perform a variety of functions to support the vision of nomadic computing across varying platforms. In previous work we have used middleware to perform a new capability, application session handoff, using a single Middleware Server to provide all functionality. However, to improve the scalability of our architecture, we have designed an efficient distributed Middleware Service layer that properly maintains application session handoff semantics while being able to service a large number of clients. We show that this service layer improves the scalability of general client-to-application server interaction as well as the specific case of application session handoff. We detail protocols involved in performing handoff and analyse an implementation of the architecture that supports the use of a real medical teaching tool. From experimental results it can be seen that our Middleware Service e...
Handoff of Application Sessions Across Time and Space ... pa-per we address the issue of applicat... more Handoff of Application Sessions Across Time and Space ... pa-per we address the issue of application session transfer for unin-terrupted data access across this diverse ... From this effort we have established baseline performance metrics and have found that the overhead is within ...
The Community Seismic Network (CSN) has partnered with the NASA Jet Propulsion Laboratory (JPL) t... more The Community Seismic Network (CSN) has partnered with the NASA Jet Propulsion Laboratory (JPL) to initiate a campus-wide structural monitoring program of all buildings on the premises. The JPL campus serves as a proxy for a densely instrumented urban city with localized vibration measurements collected throughout the free-field and built environment. Instrumenting the entire campus provides dense measurements in a horizontal geospatial sense for soil response; in addition five buildings have been instrumented on every floor of the structure. Each building has a unique structural system as well as varied amounts of structural information via structural drawings, making several levels of assessment and evaluation possible. Computational studies with focus on damage detection applied to the campus structural network are demonstrated for a collection of buildings. For campus-wide real-time and post-event evaluation, ground and building response products using CSN data are illustrating ...
The Kluwer International Series in Engineering and Computer Science, 2000
Open architecture systems present many challenges for system and application designers. Problems ... more Open architecture systems present many challenges for system and application designers. Problems such as selecting adaptations, reliability, and security are overly complicated in traditional adaptation paradigms. Frequently, network applications operate peer to peer — where it is in the best interest of both parties to communicate. This model can be exploited to our benefit in open architectures. By shifting adaptation models towards co-operative adaptation along endpoints, hard problems can be simplified; at the same time, we can still maintain desired flexibility.
2002 IEEE International Conference on Communications. Conference Proceedings. ICC 2002 (Cat. No.02CH37333), 2002
Ubiquitous computing across a variety of wired and wireless connections still lacks an effective ... more Ubiquitous computing across a variety of wired and wireless connections still lacks an effective security architecture. In our research work, we address the specific issue of designing and building a security architecture for Application Session Handoff, a functionality which we envision will be a key component enabling ubiquitous computing. Our architecture incorporates a number of proven approaches into the new context of ubiquitous computing. We employ the Bell-LaPadula and capability models to realise access control and adopt Public Key Infrastructure (PKI)-based approaches to provide efficient and authenticated end-to-end security. To demonstrate the effectiveness of our design, we implemented an application enabled with this security architecture and showed that it incurred low latency.
Previous distributed le systems have relied on either convention or obtaining dynamic global agre... more Previous distributed le systems have relied on either convention or obtaining dynamic global agreement t o p r o vide network transparent le naming. This paper argues that neither approach can succeed as systems scale to the kind of size that is anticipated in the current decade. We propose instead a novel name mapping scheme which relies on a fragmented, selectively replicated name translation database. Updates to the naming database are coordinated by an optimistic concurrency control strategy with automatic propagation and reconciliation. A prototype of the name mapping mechanism has been implemented and is in use in the Ficus replicated le system.
The Caltech CSN project collects sensor data from thousands of personal devices for real-time res... more The Caltech CSN project collects sensor data from thousands of personal devices for real-time response to dangerous earthquakes.
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Papers by Richard Guy