Solutions to outdoor air pollution require societal changes; however, we focus on indoor home air quality to allow for individual control over the breathing environment. We present AirFeed: a real time air quality mon...
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Solutions to outdoor air pollution require societal changes; however, we focus on indoor home air quality to allow for individual control over the breathing environment. We present AirFeed: a real time air quality monitoring system that provides measurements on particulate matter, temperature, and humidity. Interactions with users based on data analysis and user/sensor feedback form distinguishable patterns between several types of activities. We can better inform the user how daily habits affect living environments. Several deployments are actively collecting data for future data analysis and improved pattern recognition.
We present MaWi - a smart phone based scalable indoor localization system. Central to MaWi is a novel framework combining two self-contained but complementary localization techniques: Wi-Fi and Ambient Magnetic Field....
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We present MaWi - a smart phone based scalable indoor localization system. Central to MaWi is a novel framework combining two self-contained but complementary localization techniques: Wi-Fi and Ambient Magnetic Field. Combining the two techniques, MaWi not only achieves a high localization accuracy, but also effectively reduces human labor in building fingerprint databases: to avoid war-driving, MaWi is designed to work with low quality fingerprint databases that can be efficiently built by only one person. Our experiments demonstrate that MaWi, with a fingerprint database as scarce as one data sample at each spot, outperforms the state-of-the-art proposals working on a richer fingerprint database.
Time-of-flight echo techniques have been proposed to estimate the distance between a local and a target station over regular WiFi radio devices. their current main shortcoming is that they are affected by severe noise...
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Time-of-flight echo techniques have been proposed to estimate the distance between a local and a target station over regular WiFi radio devices. their current main shortcoming is that they are affected by severe noise components at both stations. Our aim in this work is to quantify the noise level introduced by the target in order to derive practical limits of the ranging accuracy achievable using off-the-shelf devices. For this purpose, we develop a low-noise experimental platform which allows us to measure the echo-reply delay with very high accuracy. Our preliminary results with two popular chipsets from different manufacturers show that the median echo-reply delay at the target is never equal to the nominal SIFS value, and it deviates by approximately 10-20 ns over time, suggesting a practical ranging accuracy limit of 3 m.
Traditional communication protocols focus on how to integrate a single wireless network withthe Internet. thus data from all wireless devices in that network can be gathered, sank, and provided to users via a friendl...
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Traditional communication protocols focus on how to integrate a single wireless network withthe Internet. thus data from all wireless devices in that network can be gathered, sank, and provided to users via a friendly interface using web pages. these protocols offer limited automation. Much training is required for users to analyse data from different wireless networks. To resolve this issue, recently many researchers are contributing to design and implement an appropriate protocol for the communication between a heterogeneous wireless network and the Internet [1-3]. In this paper, we present a scalable and flexible communication protocol which is designed to work as an interface between the Internet and various wireless networks in a heterogeneous network, to store information and to provide web services to end users. Using web services, users can interact with wireless devices remotely and easily. the current implementation is based on a Linux server. this server uses different communication interfaces to talk to various wireless networks. From these communication interfaces, data is acquired, processed, and stored in the server. Algorithms are developed to analyse data in data processing stage to maximize automation. Meanwhile this server works as a web server and provides web services to remote users. Current studied wireless protocols include ZigBee, Bluetooth, and Wi-Fi. And our communication protocol can be scaled to work with more wireless protocols and developed into a distributed system.
this paper describes a new embedded networked sensor platform architecture that combines hardware and software tools providing detailed, fine-grained real-time energy usage information. We introduce the LEAP2 platform...
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ISBN:
(纸本)9780769531571
this paper describes a new embedded networked sensor platform architecture that combines hardware and software tools providing detailed, fine-grained real-time energy usage information. We introduce the LEAP2 platform, a qualitative step forward over the previously developed LEAP [13] and other similar platforms. LEAP2 is based on a new low power ASIC system and generally applicable supporting architecture that provides unprecedented capabilities for directly observing energy usage of multiple subsystems in real-time. Real-time observation with microsecond-scale time resolution enables direct accounting of energy dissipation for each computing task as well as for each hardware subsystem. the new hardware architecture is exploited with our new software tools, etop and endoscope. A series of experimental investigations provide high-resolution power information in networking, storage, memory and processing for primary embedded networked sensing applications. Using results obtained in real-time we show that for a large class of wireless sensor network nodes, there exist several interdependencies in energy consumption between different subsystems. through the use of our measurement tools we demonstrate that by carefully selecting the system operating points, energy savings of over 60% can be achieved while retaining system performance.
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