http://www.rssboard.org/rss-specification 720 https://escholarship.org/uc/cens_wps/rss Recent eScholarship items from Papers Tue, 16 Jun 2026 13:42:36 +0000 https://escholarship.org/uc/item/85f6w6sv <p>The characterization of the solar radiation environment under a forest canopy is important for both understanding temperature-dependent biological processes and validating energy balance models. A modified sinusoidal model of soil heat conductivity was used to estimate subsurface temperature and heat flux from the uneven but periodic solar heating of the soil surface due to sun flecks from a forest canopy. Using a mobile sensor platform with an infrared thermometer along an 11 m transect, a sunfleck model of soil surface temperature was tested using soil surface temperature maxima, air temperatures, and photodiodes placed on the soil surface to measure sunflecks. A pan-tilt-zoom digital camera on a 10 m tower above the site was then used to capture a time series of panoramic images of sunflecks reflected from the soil surface and to scale the sunfleck temperature model to a wide area. Finally, this image-based model of surface temperatures was combined with the modified sinusoidal... https://escholarship.org/uc/item/85f6w6sv Tue, 20 Apr 2010 00:00:00 +0000 Graham, Eric Lam, Yeung Yuen, Eric https://escholarship.org/uc/item/8pq5g7rm <p>Plant phenology relates strongly to primary productivity and the energy that enters into ecological food webs, and thus is vital in understanding ecosystem function and the effects of climate and climate change. The manual collection of phenological data is labor-intensive and not easily scalable, thus the ability to quantify leaf flush and other parameters at many locations requires innovative new methodologies such as the use of visible light digital cameras. Improved imaging performancewas obtained by using a cabled, mobile camera system that allowed a repeated image census of branches of Rhododendron occidentale in the understory along a 30m transect during leaf flush. Automatic division of acquired images into areas of interest (leaves) and background for calculating leaf area was accomplished by thresholding images in different color spaces. Transformation of the color space into the hue, saturation, and luminance (HSL) color space before thresholding resulted in a mean... https://escholarship.org/uc/item/8pq5g7rm Tue, 2 Feb 2010 00:00:00 +0000 Graham, Eric https://escholarship.org/uc/item/8867594b <p>Environmental sensor networks offer a powerful combination of distributed sensing capacity, real-time data visualization and analysis, and integration with adjacent networks and remote sensing data streams. These advances have become a reality as a combined result of the continuing miniaturization of electronics, the availability of large data storage and computational capacity, and the pervasive connectivity of the Internet. Environmental sensor networks have been established and large new networks are planned for monitoring multiple habitats at many different scales. Projects range in spatial scale from continental systems designed to measure global change and environmental stability to those involved with the monitoring of only a few meters of forest edge in fragmented landscapes. Temporal measurements have ranged from the evaluation of sunfleck dynamics at scales of seconds, to daily CO2 fluxes, to decadal shifts in temperatures. Above-ground sensor systems are partnered... https://escholarship.org/uc/item/8867594b Tue, 2 Feb 2010 00:00:00 +0000 Rundel, P W Graham, Eric https://escholarship.org/uc/item/2xr2r802 <p>Participatory sensing technologies could improve our lives and our communities, but at what cost to our privacy?</p> https://escholarship.org/uc/item/2xr2r802 Tue, 8 Sep 2009 00:00:00 +0000 Shilton, Katie https://escholarship.org/uc/item/4sn741ns <p>For decades, the Codes of Fair Information Practice have served as a model for data privacy, protecting personal information collected by governments and corporations. But professional data management standards such as the Codes of Fair Information Practice do not take into account a world of distributed data collection, nor the realities of data mining and easy, almost uncontrolled, dissemination. Emerging models of information gathering create an environment where recording devices, deployed by individuals rather than organizations, disrupt expected flows of information in both public and private spaces. We suggest expanding the Codes of Fair Information Practice to protect privacy in this new data reality. An adapted understanding of the Codes of Fair Information Practice can promote individuals’ engagement with their own data, and apply not only to governments and corporations, but software developers creating the data collection programs of the 21st century. To support... https://escholarship.org/uc/item/4sn741ns Fri, 28 Aug 2009 00:00:00 +0000 Shilton, Katie Burke, Jeffrey A Estrin, D Govindan, Ramesh Hansen, Mark Kang, Jerry Mun, Min https://escholarship.org/uc/item/6w6295sp <p>At UCLA, the Center for Embedded Network Sensing (CENS) in the School of Engineering received NSF funding for a unique project titled: Women @ CENS, created to explore issues of gender equity in engineering and computer science (ECS) undergraduate research internship programs. The Women @ CENS project includes two studies: 1) an evaluation of our own CENS REU program and 2) a national study of REUs in ECS. The goals of these studies were to learn about promising practices in addressing gender equity in the REU setting from our own summer internship program, and to learn about what other REUs were doing in regards to promoting gender equity such that more women will choose to pursue advanced degrees and faculty careers in ECS. Study One utilizes the evaluation of the CENS REU over four program years to understand what has and has not worked for our female students in particular. For Study Two, we surveyed program directors of NSF funded Computer Science and Engineering REUs... https://escholarship.org/uc/item/6w6295sp Thu, 7 May 2009 00:00:00 +0000 Kim, Karen Fann, Amy Misa-Escalante, Kimberly https://escholarship.org/uc/item/28p3k1rj <p>The nees@UCLA mobile field laboratory was utilized to collect forced and ambient vibration data from a four-story reinforced concrete (RC) building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively. Floor accelerations, interstory displacements, and column and slab curvature distributions were monitored during the tests using accelerometers, linear variable differential transformers (LVDTs) and concrete strain gauges. The use of dense instrumentation enabled verification of common modeling assumptions related to rigid diaphragms and soil-structure-interaction. The first six or seven natural frequencies, mode shapes, and damping ratios were identified. Significant decreases in frequency cor responded to increases in shaking amplitude, most notably in the N-S direction of the building, most likely due to preexisting diagonal joint cracks... https://escholarship.org/uc/item/28p3k1rj Fri, 19 Dec 2008 00:00:00 +0000 Yu, Eunjong Skolnik, Derek Whang, Daniel H. Wallace, John W. https://escholarship.org/uc/item/1627v77m <p>This paper presents Confidence, a tool for identifying and addressing faults in wireless sensing systems. Confidence pinpoints potential sensor and network faults in real time, allowing users to validate unexpected data and address any failures in the field. By introducing a well defined, low-dimension feature space, and functions to map sensor data into this space, we are able to achieve fault detection and diagnosis with relatively simple mechanisms such as outlier detection. Users can directly modify system outcomes by altering a classification label in instances when Confidence's automated algorithm draws the wrong inference. This label is applied to all similar points in the feature space, enabling Confidence to learn from user interaction in the field. This abstraction for incorporating user knowledge provides a lightweight and easy-to-understand interface for the user, while limiting user burden and reducing the required a priori environmental knowledge. Confidence has... https://escholarship.org/uc/item/1627v77m Fri, 17 Oct 2008 00:00:00 +0000 Ramanathan, Nithya https://escholarship.org/uc/item/7nt8d117 NIMSAQ: A novel system for autonomous sensing of aquatic environments https://escholarship.org/uc/item/7nt8d117 Mon, 14 Jul 2008 00:00:00 +0000 Stealey M. Singh A. Batalin M. Jordan B. Kaiser W. https://escholarship.org/uc/item/5gt3m03c The Marginal Utility of Cooperation in Sensor Networks https://escholarship.org/uc/item/5gt3m03c Mon, 14 Jul 2008 00:00:00 +0000 Y.-C. Tong G. Pottie https://escholarship.org/uc/item/4cx5t82z <p>This article presents a study that compares detected structural communities in a coauthorship network to the socioacademic characteristics of the scholars that compose the network. The coauthorship network was created from the bibliographic record of an overt interdisciplinary research group focused on sensor networks and wireless communication. The popular leading eigenvector community detection algorithm was employed to assign a structural community to each scholar in the network. Socioacademic characteristics were gathered from the scholars and include such information as their academic department, academic affiliation, country of origin, and academic position. A Pearson's \$\chi^2\$ test, with a simulated Monte Carlo, revealed that structural communities best represent groupings of individuals working in the same academic department and at the same institution. A generalization of this result indicates that, contrary to the common conception of a multi-institutional interdisciplinary... https://escholarship.org/uc/item/4cx5t82z Mon, 14 Jul 2008 00:00:00 +0000 Rodriguez, Marko A Pepe, Alberto https://escholarship.org/uc/item/1nx4w72g Seeing Our Signals: Combining location traces and web-based models for personal discovery https://escholarship.org/uc/item/1nx4w72g Mon, 14 Jul 2008 00:00:00 +0000 E. Agapie G. Chen D. Houston E. Howard J. Kim M. Y. Mun A. Mondschein S. Reddy R. Rosario J. Ryder A. Steiner J. Burke E. Estrin M. Hansen M. Rahimi https://escholarship.org/uc/item/12v1d7w3 Adaptive Sampling With Multiple Mobile Robots https://escholarship.org/uc/item/12v1d7w3 Mon, 14 Jul 2008 00:00:00 +0000 Bin Zhang Gaurav S. Sukhatme https://escholarship.org/uc/item/167720v5 <p>• Characterization of spatial and temporal variation of soil respiration coupled with fine root and rhizomorph dynamics is necessary to understand the mechanisms that regulate soil respiration.</p><p>• A dense wireless network array of soil CO2 sensors in combination with minirhizotron tubes was used to continuously measure soil respiration over 1 yr in a mixed conifer forest in California, USA, in two adjacent areas with different vegetation types: an area with woody vegetation (Wv) and an area with scattered herbaceous vegetation (Hv).</p><p>• Annual soil respiration rates and the lengths of fine roots and rhizomorphs were greater at Wv than at Hv. Soil respiration was positively correlated with fine roots and rhizomorphs at Wv but only with fine roots at Hv. Diel and seasonal soil respiration patterns were decoupled with soil temperature at Wv but not at Hv. When decoupled, higher soil respiration rates were observed at increasing temperatures, demonstrating a hysteresis... https://escholarship.org/uc/item/167720v5 Sat, 12 Jul 2008 00:00:00 +0000 Vargas, Rodrigo Allen, Michael F. https://escholarship.org/uc/item/90j149pp <p>Urban sensing systems that use mobile phones enable individuals and communities to collect and share data with unprecedented speed, accuracy and granularity. But employing mobile handsets as sensor nodes poses new challenges for privacy, data security, and ethics. To address these challenges, CENS is developing design principles based upon understanding privacy regulation as a participatory process. This paper briefly reviews related literature and introduces the concept of participatory privacy regulation. PPR reframes negotiations of social context as an important part of participation in sensing-supported research. It engages participants in ethical decision-making and the meaningful negotiation of personal boundaries and identities. We use PPR to establish a set of design principles based on our application drivers.</p> https://escholarship.org/uc/item/90j149pp Mon, 21 Apr 2008 00:00:00 +0000 Shilton, Katie Burke, Jeffrey A Estrin, D Hansen, Mark Srivastava, Mani https://escholarship.org/uc/item/6xt4d270 <p>Dynamics of wireless communication, resource constraints, and application diversity pose significant challenges to data transport control in wireless sensor networks. In this chapter, we examine the issue of data transport control in the context of two typical communication patterns in wireless sensor networks: convergecast and broadcast. We study the similarity and differences of data transport control in convergecast and broadcast, we discuss existing convergecast and broadcast protocols, and we present open issues for data transport control in wireless sensor networks.</p> https://escholarship.org/uc/item/6xt4d270 Wed, 2 Apr 2008 00:00:00 +0000 Zhang, Hongwei Naik, Vinayak S https://escholarship.org/uc/item/1zj2j21d <p>Wireless sensor networks are new type of emerging networks with bunch of applications in all fields due to their low cost and low power scheme. As these networks follow open wireless communication, they undergo dynamic node problems and fault node detection due to malicious node activities. In this paper we overcome these problems with the help of algorithms that will provide uninterrupted communication and also save node’s energy and time.function. It is therefore critical for the base station to find out the reason for the node failure. To distinguish these cases, the base station needs to trace all dead nodes.</p> https://escholarship.org/uc/item/1zj2j21d Fri, 1 Feb 2008 00:00:00 +0000 mahanaz, tabassum Devarakonda, Swathi https://escholarship.org/uc/item/77r2j6p0 <p>This paper presents different applications of wireless sensing systems in environmental sensing and sensing in everyday life.</p> https://escholarship.org/uc/item/77r2j6p0 Thu, 6 Dec 2007 00:00:00 +0000 Estrin, D https://escholarship.org/uc/item/8v01m8wj <p>Participatory sensing takes advantage of the pervasive nature of mobile phones to collect data about the urban environment using the available sensors. Campaignr makes collecting this data as simple as a few button pushes. It provides access to the sensors in a robust and flexible way that hides the complexities of the mobile embedded phone environment. This paper describes the design choices and provides some numerical evaluation of Campaignr. Campaignr has been and is being actively used as the data collection method for many research pro jects, both internally and externally.</p> https://escholarship.org/uc/item/8v01m8wj Fri, 26 Oct 2007 00:00:00 +0000 Joki, August Burke, Jeffrey A Estrin, D https://escholarship.org/uc/item/9xc0f566 <p>We propose a novel algorithm employing particle filters for acoustic source tracking in a reverberant environment. By incorporating the likelihood function computed through Approximate Maximum-Likelihood (AML) method, the proposed algorithm is applicable to wideband sources and can be implemented for multiple sources tracking. Both computer simulation and experimental results show the effectiveness of the proposed algorithm.</p> https://escholarship.org/uc/item/9xc0f566 Tue, 2 Oct 2007 00:00:00 +0000 Chen, Chiao-En Ali, Andreas M Lorenzelli, F. Hudson, Ralph E. Yao, K https://escholarship.org/uc/item/9q5083rh <p>We address the problem of energy efficient sensing by adaptively coordinating the sleep schedules of sensor nodes while guaranteeing that values of sleeping nodes can be recovered from the awake nodes within a user’s specified error bound. Our approach has two phases. First, development of models for predicting measurement of one sensor using data from other sensors. Second, creation of the maximal number of subgroups of disjoint nodes, each of whose data is sufficient to recover the measurements of the entire sensor network. For prediction of the sensor measurements, we introduce a new optimal non-parametric polynomial time isotonic regression. Utilizing the prediction models, the sleeping coordination problem is abstracted to a domatic number problem and is optimally solved using an ILP solver. To capture evolving dynamics of the instrumented environment, we monitor the prediction errors occasionally to trigger adaptation of the models and domatic partitions... https://escholarship.org/uc/item/9q5083rh Tue, 2 Oct 2007 00:00:00 +0000 Koushanfar, Farinaz Taft, Nina Potkonjak, Miodrag https://escholarship.org/uc/item/9ph492p2 <p>Many environmental applications require high temporal frequency (rapidly changing) and spatially distributed phenomena to be sampled with high fidelity. This requires mobile sensing elements to perform guided sampling in regions of high variability. We propose a multiscale approach for efficiently sampling such phenomena. This approach introduces a hierarchy of sensors according to the sampling fidelity, spatial coverage, and mobility characteristics. In this paper, we report the development of a two-tier multiscale system where information from a low-fidelity, high spatial (global) sensor actuates a mobile robotic node, carrying a high-fidelity, low spatial coverage (spot measurement) sensor, to perform guided sampling in the regions of high phenomenon variability. As a case study of the proposed multiscale paradigm, we investigated the spatiotemporal distribution of the light intensity in a forest understory. The performance of the multiscale approach is verified in simulation... https://escholarship.org/uc/item/9ph492p2 Tue, 2 Oct 2007 00:00:00 +0000 Singh, Amarjeet Budzik, Diane Chen, Willie Batalin, Maxim Kaiser, W J https://escholarship.org/uc/item/9mf6x4sx <p>We have developed statistical error modeling techniques for acoustic signal detection-based ranging measurements in the framework of wireless ad-hoc sensor networks (WASNs). The models are used as the basis for solving the location discovery problem in sensor networks. We first demonstrate that the major difficulty in location discovery is how to treat errors by proving the location discovery in presence of noisy measurements is a NP-complete problem, even in onedimensional space. Consequently, we formulate the location discovery as an instance of nonlinear function minimization that optimizes each of the empirically derived statistical error models. The minimization problem is then solved using a conjugate gradient-based nonlinear function optimization solver.</p><p>We validate the efficiency of the approach by conducting comprehensive experiments on both deployed and simulated WASNs. The results indicate that the statistical model-based approach significantly improves the... https://escholarship.org/uc/item/9mf6x4sx Tue, 2 Oct 2007 00:00:00 +0000 Feng, Jessica Girod, Lewis Potkonjak, Miodrag https://escholarship.org/uc/item/9jz9s82r Induction of Prototypes in a Robotic Setting Using Local Search MDL https://escholarship.org/uc/item/9jz9s82r Tue, 2 Oct 2007 00:00:00 +0000 G.M. Kobele J. Riggle R. Brooks D. Friedlander C. Taylor E. Stabler https://escholarship.org/uc/item/9c16b6dd <p>Sensor network has experienced world-wide explosive interests in recent years. It combines the technology of modern microelectronic sensors, embedded computational processing systems, and modern computer and wireless networking methodologies. In this overview paper, we first provide some rationales for the growth of sensor networking. Then we discuss various basic concepts and hardware issues. Four basic application cases in the US. National Science Foundation funded Ceneter for Embedded Networked Sensing program at UCLA are presented. Finally, six challenging issues in sensor networks are discussed. Numerous references including relevant papers, books, and conferences that have appeared in recent years are given.</p> https://escholarship.org/uc/item/9c16b6dd Tue, 2 Oct 2007 00:00:00 +0000 Yao, K https://escholarship.org/uc/item/9bk26563 <p>Large-scale networks of battery-operated wireless image sensors have become technologically feasible. However, it is still unclear how we can benefit from large-scale deployments of imagers. In this paper, we argue that using a large number of low-power image sensors is useful and necessary in many cases. For instance, occluded environments cannot be efficiently observed with a small number of cameras. In this case, distributed imagers can provide better coverage due to minimum infrastructure requirements and availability in large numbers. Additional benefits, such as pose diversity, statistical advantages, and multiple perspectives are discussed in detail using application examples and qualitative arguments.</p> https://escholarship.org/uc/item/9bk26563 Tue, 2 Oct 2007 00:00:00 +0000 Rahimi, Mohammed Ahmadian, Shaun Zats, David Laufer, Rafael Estrin, D https://escholarship.org/uc/item/96t4z8xd <p>Ideally both spectral and time domain data could be used to compute the total building response and to make predic- tions of damage patterns based on various input scenarios. The combination of frequency change information coupled with that provided by wavefield properties can pinpoint the time and location of damage more accurately, especially for densely instru- mented structures such as the 17-story UCLA Factor building. The 72-sensor embedded seismic array in the Factor building, recording continuous waveforms at 500 Hz, makes it possible to observe subtle changes in dynamic characteristics between pairs of floors and to relate the measurements to system properties such as changes in stiffness due to a column failure. The high dy- namic range of the 24-bit digitizers allows both strong motions and ambient vibrations to be recorded with reasonable sig- nal-to-noise ratios. Temporary decreases in frequencies of Factor building modes of vibration have been correlated... https://escholarship.org/uc/item/96t4z8xd Tue, 2 Oct 2007 00:00:00 +0000 Kohler, Monica Heaton, Thomas H. Govindan, Ramesh Davis, Paul Estrin, D. https://escholarship.org/uc/item/96m2k5tx Spatially homogeneous dynamic textures https://escholarship.org/uc/item/96m2k5tx Tue, 2 Oct 2007 00:00:00 +0000 G. Doretto E. Jones S. Soatto https://escholarship.org/uc/item/94n787sj <p>This paper reports the first application of iterative experimental design methodology for high spatiotemporal resolution characterization of river and lake aquatic systems performed using mobile robot sensing systems. Both applications involve dynamic phenomena spread over large spatial domain: 1) Characterization of contaminant concentration and flow at the confluence of two major rivers displaying dynamics due to flow of the water; and 2) Characterization of rapidly evolving biological processes such as phytoplankton dynamics in a lake system. We describe the development and application of a new general purpose method for mobile robot sensing in such environments - Iterative experiment Design for Environmental Applications (IDEA). IDEA introduces in-field adaptation of mobile robotic sensing system. Analysis of the complex spatial and temporal structures associated with each observed environment is presented. Detailed characterization of the observed environment using IDEA... https://escholarship.org/uc/item/94n787sj Tue, 2 Oct 2007 00:00:00 +0000 Singh, Amarjeet Batalin, Maxim Stealey, Michael Chen, Victor Hansen, Mark Harmon, T C Sukhatme, Gaurav Kaiser, W J https://escholarship.org/uc/item/9401q7rc An Experimental Study of Localization Using Wireless Ethernet https://escholarship.org/uc/item/9401q7rc Tue, 2 Oct 2007 00:00:00 +0000 A. Howard S. Siddiqi G.S. Sukhatme https://escholarship.org/uc/item/91p587cn <p><em>Aureococcus anophagefferens</em>, a harmful bloom-forming alga responsible for brown tides in estuaries of the Middle Atlantic U.S., has been investigated by atomic force microscopy for the first time, using probes functionalized with a monoclonal antibody specific for the alga. The rupture force between a single monoclonal antibody and the surface of <em>A. anophagefferens</em> was experimentally found to be 246±11 pN at the load rate of 12 nN/s. Force histograms for <em>A. anophagefferens</em> and other similarly-sized algae are presented and analyzed. The results illustrate the effects of load rates, and demonstrate that force-distance measurements can be used to build biosensors with high signal-to-noise ratios for <em>A. anophagefferens</em>. The methods described in this paper can be used, in principle, to construct sensors with single-cell resolution for arbitrary cells for which monoclonal antibodies are available.</p> https://escholarship.org/uc/item/91p587cn Tue, 2 Oct 2007 00:00:00 +0000 Lee, Alexander S. Mahapatro, Mrinal Caron, David A. Requicha, Ari Stauffer, Beth Thompson, Mark E. Zhou, Chongwu https://escholarship.org/uc/item/90r880ch <p>As data become scientific capital, digital libraries of data become more valuable. To build good tools and services, it is necessary to understand scientists’ data practices. We report on an exploratory study of habitat ecologists and other participants in the Center for Embedded Networked Sensing. These scientists are more willing to share data already published than data that they plan to publish, and are more willing to share data from instruments than hand-collected data. Policy issues include responsibility to provide clean and reliable data, concerns for liability and misappropriation of data, ways to handle sensitive data about human subjects arising from technical studies, control of data, and rights of authorship. We address the implications of these findings for tools and architecture in support of digital data libraries.</p> https://escholarship.org/uc/item/90r880ch Tue, 2 Oct 2007 00:00:00 +0000 Borgman, C L Wallis, J C Enyedy, N https://escholarship.org/uc/item/8t06k2rw Aggregation in sensor networks: An energy-accuracy trade-off https://escholarship.org/uc/item/8t06k2rw Tue, 2 Oct 2007 00:00:00 +0000 A. Boulis S. Ganeriwal M. B. Srivastava https://escholarship.org/uc/item/8mb6468v <p>Efficient and complete data collection is one of the most important tasks in wireless ad-hoc sensor networks. Additionally, the collection of the full data set should be performed in the most resource efficient way, thus prolonging the battery lifetime of the network. We introduce a new approach for energy efficient data collection through the use of staggered sampling. Staggered sampling means that at each sampling moment (epoch) only a small percentage of sensors collect (sample) data. The proposed approach leverages on statistical relationships between samples taken from different sensors and/or at different epochs for the prediction of the non-sampled sensor data.</p><p>The main goal of the approach is to ensure complete collection of data during a periodic cycle while minimizing the number of sensor readings collected at any point in time. Complete data collection is confirmed by ensuring that each sensor is either sampled at each epoch or the data sample can be accurately... https://escholarship.org/uc/item/8mb6468v Tue, 2 Oct 2007 00:00:00 +0000 Wong, J L Megerian, Seapahn Potkonjak, Miodrag https://escholarship.org/uc/item/8d084588 Coverage, Exploration and Deployment by a Mobile Robot and Communication Network https://escholarship.org/uc/item/8d084588 Tue, 2 Oct 2007 00:00:00 +0000 M. Batalin G. S. Sukhatme https://escholarship.org/uc/item/8ct2h4pk Understanding Packet Delivery Performance In Dense Wireless Sensor Networks https://escholarship.org/uc/item/8ct2h4pk Tue, 2 Oct 2007 00:00:00 +0000 Jerry Zhao R. Govindan https://escholarship.org/uc/item/895068dn <p>Observing systems facilitate scientific studies by instrumenting the real world and collecting corresponding measurements, with the aim of detecting and tracking phenomena of interest. Our AMBROSia project focuses on a class of observing systems which are <em>embedded</em> into the environment, consist of <em>stationary and mobile</em> sensors, and <em>react</em> to collected observations by reconfiguring the system and adapting which observations are collected next. In this paper, we report on recent research directions and corresponding results in the context of AMBROSia.</p> https://escholarship.org/uc/item/895068dn Tue, 2 Oct 2007 00:00:00 +0000 Caron, David A. Das, Abhimanyu Dhariwal, Amit Golubchik, Leana Govindan, Ramesh Kempe, David Oberg, Carl Sharma, Abhishek Stauffer, Beth Sukhatme, Gaurav zhang, bin https://escholarship.org/uc/item/8773s6xx <p>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... https://escholarship.org/uc/item/8773s6xx Tue, 2 Oct 2007 00:00:00 +0000 Singh, Amarjeet Batalin, Maxim Stealey, Michael Zhang, Bin Dhariwal, Amit Stauffer, Beth Moorthi, Stefanie Oberg, Carl de Menezes Pereira, Arvind Antonio Chen, Victor Lam, Yeung Caron, David Hansen, Mark Kaiser, W J Sukhatme, Gaurav https://escholarship.org/uc/item/84w8b6b9 <p>As part of our research, we have designed and developed sensor-actuated network for marine monitoring. The network consists of ten static buoy nodes and one mobile robotic boat for real-time in-situ measurements and analysis of chemical, physical and biologically pertinent phenomena governing the abundance of micro-organisms at relevant spatio-temporal scales. The goal of the network is to obtain high-resolution information on the spatial and temporal distribution of plankton assemblages in aquatic environments using the in situ presence afforded by the network, and to make possible network-enabled robotic sampling of hydrographic features of interest. This work constitutes advances in (1) real-time observing in aquatic ecosystems and (2) sensor- actuated sampling for biological analysis.</p><p>Ultimately such systems will be able to establish patterns in the sensed data, and use their mobility to adapt sample collection, a major step forward in the use of embedded... https://escholarship.org/uc/item/84w8b6b9 Tue, 2 Oct 2007 00:00:00 +0000 Dhariwal, Amit zhang, bin de Menezes Pereira, Arvind Antonio Oberg, Carl Stauffer, Beth Moorthi, Stefanie Caron, David A. Sukhatme, Gaurav https://escholarship.org/uc/item/7z6076vr <p>In an effort to balance water reuse and protect groundwater quality when irrigating with reclaimed water, an adaptive management scheme with feedback control has been developed and is currently undergoing testing. A wirelessly networked sensor array is being deployed at an agricultural research plot to provide system feedback. Several multi-level sensing arrays (pylons) equipped with soil moisture, temperature, and nitrate sensors are installed throughout the field site. The pylon is coupled to a simulation and management algorithm to optimize irrigation scheduling. Specifically, a nonlinear programming-based control algorithm, referred to as Receding Horizon Feedback Control (RHFC), is proposed to maximize water reuse and maintain nitrate concentration in groundwater below the regulatory threshold. Each pylon supplies the irrigation scheduling algorithm with real-time field information about water infiltration and distribution, nitrate propagation, and heat transport (in support... https://escholarship.org/uc/item/7z6076vr Tue, 2 Oct 2007 00:00:00 +0000 Park, Yeonjeong Ewart, John Harmon, T C https://escholarship.org/uc/item/7vd51134 Coping with Irregular Spatio-Temporal Sampling in Sensor Networks https://escholarship.org/uc/item/7vd51134 Tue, 2 Oct 2007 00:00:00 +0000 D. Ganesan S. Ratnasamy H. Wang D. Estrin https://escholarship.org/uc/item/7kx4f8wx Cross-Sectional River Hydraulics and Water Quality Characterization Using Rapidly Deployable Networked Info-Mechanical Systems (NIMS RD) https://escholarship.org/uc/item/7kx4f8wx Tue, 2 Oct 2007 00:00:00 +0000 Fisher, Jason Harmon, T C Kaiser, W J https://escholarship.org/uc/item/7905k029 <p>As part of our research, we have designed and developed sensor-actuated network for marine monitoring. The network consists of ten static buoy nodes and one mobile robotic boat for real-time in-situ measurements and analysis of chemical, physical and biologically pertinent phenomena governing the abundance of micro-organisms at relevant spatio-temporal scales. The goal of the network is to obtain high-resolution information on the spatial and temporal distribution of plankton assemblages in aquatic environments using the in situ presence afforded by the network, and to make possible network-enabled robotic sampling of hydrographic features of interest.</p> https://escholarship.org/uc/item/7905k029 Tue, 2 Oct 2007 00:00:00 +0000 Dhariwal, Amit zhang, bin de Menezes Pereira, Arvind Antonio Oberg, Carl Stauffer, Beth Moorthi, Stefanie Caron, David A. Sukhatme, Gaurav https://escholarship.org/uc/item/7694j52g A Wireless Sensor Network for Structural Monitoring https://escholarship.org/uc/item/7694j52g Tue, 2 Oct 2007 00:00:00 +0000 N. Xu S. Rangwala K. Chintalapudi D. Ganesan A. Broad R. Govindan D. Estrin https://escholarship.org/uc/item/74h0v84v <p>In this study, we formulate an improved finite element model-updating method to address the numerical difficulties associated with ill conditioning and rank deficiency. These complications are frequently encountered model-updating problems, and occur when the identification of a larger number of physical parameters is attempted than that warranted by the information content of the experimental data. Based on the standard bounded variables least-squares (BVLS) method, which incorporates the usual upper/lower-bound constraints, the proposed method (henceforth referred to as BVLSrc) is equipped with novel sensitivity-based relative constraints. The relative constraints are automatically constructed using the correlation coefficients between the sensitivity vectors of updating parameters. The veracity and effectiveness of BVLSrc is investigated through the simulated, yet realistic, forced-vibration testing of a simple framed structure using its frequency response function as input... https://escholarship.org/uc/item/74h0v84v Tue, 2 Oct 2007 00:00:00 +0000 Yu, Eunjong Taciroglu, Ertugrul Wallace, J W https://escholarship.org/uc/item/73s798t3 <p>In this paper we explore the application of data mining techniques to the problem of acoustic recognition of bird species. Most bird song analysis tools produce a large amount of spectral and temporal attributes from the acoustic signal. The identification of distinctive features has become critical in resource constrained applications such as habitat monitoring by sensor networks. Reducing computational requirements makes it affordable to run a classifier on devices with power consumption constraints, such as nodes in a sensor network. Experimental results demonstrate that considerable dimensionality reduction can be achieved without significant loss in classification efficiency.</p> https://escholarship.org/uc/item/73s798t3 Tue, 2 Oct 2007 00:00:00 +0000 Vilches, Erika Escobar, Ivan A. Vallejo, E E Taylor, C E https://escholarship.org/uc/item/6xn7x711 Integral Invariant Signatures https://escholarship.org/uc/item/6xn7x711 Tue, 2 Oct 2007 00:00:00 +0000 S. Manay A. J. Yezzi B. W. Hong S. Soatto https://escholarship.org/uc/item/6xk216kv Autonomous Deployment and Repair of a Sensor Network Using an Unmanned Aerial Vehicle https://escholarship.org/uc/item/6xk216kv Tue, 2 Oct 2007 00:00:00 +0000 P. Corke S. Hrabar R. Peterson D. Rus S. Saripalli G. Sukhatme https://escholarship.org/uc/item/6r96j4rb <p>Embedded systems pose unique challenges to Java application developers and virtual machine designers. Chief among these challenges is the memory footprint of both the virtual machine and the applications that run within it. With the rapidly increasing set of features provided by the Java language, virtual machine designers are often forced to build custom implementations that make various tradeoffs between the footprint of the virtual machine and the subset of the Java language and class libraries that are supported. In this paper, we present the ExoVM, a system in which an application is initialized in a fully featured virtual machine, and then the code, data, and virtual machine features necessary to execute it are packaged into a binary image. Key to this process is <em>feature analysis</em>, a technique for computing the reachable code and data of a Java program and its implementation inside the VM simultaneously. The ExoVM reduces the need to develop customized embedded... https://escholarship.org/uc/item/6r96j4rb Tue, 2 Oct 2007 00:00:00 +0000 Titzer, B L Joshua Auerbach David F. Bacon Palsberg, J https://escholarship.org/uc/item/6r5652p8 <p>Observing systems facilitate scientific studies by instrumenting the real world and collecting corresponding measurements, with the aim of detecting and tracking phenomena of interest. A wide range of critical environmental monitoring objectives in resource management, environmental protection, and public health all require distributed observing systems. The goal of such systems is to help scientists verify or falsify hypotheses with useful samples taken by the stationary and mobile units, as well as to analyze data autonomously to discover interesting trends or alarming conditions. In our project, we focus on a class of observing systems which are <em>embedded</em> into the environment, consist of <em>stationary and mobile</em> sensors, and <em>react</em> to collected observations by reconfiguring the system and adapting which observations are collected next. In this paper, we give an overview of our project in the context... https://escholarship.org/uc/item/6r5652p8 Tue, 2 Oct 2007 00:00:00 +0000 Golubchik, Leana Caron, David A. Das, Abhimanyu Dhariwal, Amit Govindan, Ramesh Kempe, David Oberg, Carl Sharma, Abhishek Stauffer, Beth Sukhatme, Gaurav zhang, bin https://escholarship.org/uc/item/6jk7c8bt <p>The <em>nees</em>@UCLA mobile field laboratory was utilized to collect data from forced and ambient vibration testing of a four-story RC building damaged in the 1994 Northridge earthquake. Both low amplitude broadband and moderate amplitude harmonic excitation were applied using a linear shaker and two eccentric mass shakers, respectively, and ambient vibrations were measured before and after each forced vibration test. Accelerations, interstory displacements, and curvature distributions were monitored using accelerometers, LVDTs and concrete strain gauges. Natural frequencies and the associated mode shapes for the first 7 modes were identified. Fundamental frequencies determined from the eccentric mass shaker tests were 70% to 75% of the values determined using ambient vibration data, and 92% to 93% of the values determined using the linear shaker test data. Larger frequency drops were observed in the NS direction of the building, apparently due to damage that was induced... https://escholarship.org/uc/item/6jk7c8bt Tue, 2 Oct 2007 00:00:00 +0000 Yu, Eunjong Skolnik, Derek Whang, Daniel Wallace, J W https://escholarship.org/uc/item/6g72w7wk <p>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. In spite of the recent advancements in technology, currently available systems have many constraints that preclude long term, remote, autonomous, high resolution monitoring in the real environment. 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. The scientific objective of this investigation was to characterize the transport and mixing phenomena at the confluence of two distinctly different river streams - San Joaquin River and its tributary Merced River. 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... https://escholarship.org/uc/item/6g72w7wk Tue, 2 Oct 2007 00:00:00 +0000 Singh, Amarjeet Batalin, Maxim Chen, Victor Stealey, Michael Jordan, Brett Fisher, Jason Harmon, T C Hansen, Mark Kaiser, W J https://escholarship.org/uc/item/6fs4559s <p>e-Science promises to increase the pace of science via fast, distributed access to computational resources, analytical tools, and digital libraries. “Big science” fields such as physics and astronomy that collaborate around expensive instrumentation have constructed shared digital libraries to manage their data and documents, while “little science” research areas that gather data through hand-crafted fieldwork continue to manage their data locally. As habitat ecology researchers begin to deploy embedded sensor networks, they are confronting an array of challenges in capturing, organizing, and managing large amounts of data. The scientists and their partners in computer science and engineering make use of common datasets but interpret the data differently. Studies of this field in transition offer insights into the role of digital libraries in e-Science, how data practices evolve as science becomes more instrumented,... https://escholarship.org/uc/item/6fs4559s Tue, 2 Oct 2007 00:00:00 +0000 Borgman, C L Wallis, J C Enyedy, N https://escholarship.org/uc/item/6cm2g31x <p>Increasing demands on water supplies, along with concerns about non-point source pollution, and water quality–based ecological factors all point to the need for observing stream flow perturbations and pollutant discharges at higher resolution than has been practical until now. This work presents a rapidly deployable Networked Infomechanical System (NIMS RD) technology for observing spatiotemporal variability in hydraulic and chemical properties across stream channels. NIMS RD is comprised of two supporting towers and a suspension cable delivering power and Internet connectivity for controlling and actuating the tram-like NIMS unit. The NIMS unit is capable of raising and lowering a payload of sensors, allowing a preprogrammed or data-actuated adaptive scan to be completed across a stream channel. In this paper, NIMS RD is demonstrated in two relevant cases: (1) elucidating spatiotemporal variations in nutrients and other biologically significant stream constituents in Medea... https://escholarship.org/uc/item/6cm2g31x Tue, 2 Oct 2007 00:00:00 +0000 Harmon, T C Ambrose, Richard F Gilbert, Robert Fisher, Jason Stealey, Michael Kaiser, W J https://escholarship.org/uc/item/69s78776 <p>Wireless sensor networks consist of a system of distributed sensors embedded in the physical world, and promise to allow observation of previously unobservable phenomena. Since they are exposed to unpredictable environments, sensor-network applications must handle a wide variety of faults: software errors, node and link failures, and network partitions. The code to manually detect and recover from faults crosscuts the entire application, is tedious to implement correctly and efficiently, and is fragile in the face of program modifications. We investigate language support for modularly managing faults. Our insight is that such support can be naturally provided as an extension to existing “macroprogramming” systems for sensor networks. In such a system, a programmer describes a sensor network application as a centralized program; a compiler then produces equivalent node-level programs. We describe a simple checkpoint API for macroprograms, which can be automatically implemented... https://escholarship.org/uc/item/69s78776 Tue, 2 Oct 2007 00:00:00 +0000 Gummadi, Ramakrishna Kothari, Nupur Millstein, Todd Govindan, Ramesh https://escholarship.org/uc/item/6469d2v4 <p>It is currently difficult to build practical and reliable programming systems out of distributed and resource-constrained sensor devices. The state of the art in today's sensornet programming is centered around a component-based language called nesC. nesC is a <em>node-level</em> language-a program is written for an individual node in the network-and nesC programs use the services of an operating system called TinyOS. We are pursuing an approach to programming sensor networks that significantly raises the level of abstraction over this practice. The critical change is one of perspective: rather than writing programs from the point of view of an individual node, programmers implement a <em>central</em> program that conceptually has access to the entire network. This approach pushes to the compiler the task of producing node-level programs that implement the desired behavio.</p><p>We present the Pleiades programming language, its compiler, and its runtime. The Pleiades language... https://escholarship.org/uc/item/6469d2v4 Tue, 2 Oct 2007 00:00:00 +0000 Kothari, Nupur Gummadi, Ramakrishna Millstein, Todd Govindan, Ramesh https://escholarship.org/uc/item/63g6k6qx <p>Seasonal tropical forests are currently experiencing rapid deforestation and changing land management practices, which in turn may permanently transform mature forests into more shrub-herbaceous dominated plant communities and planted pastures. Effective restoration efforts are therefore essential for maintaining the biodiversity and ecosystem functioning in seasonal tropical forests, yet before implementing restoration efforts we need to better understand mechanisms influencing secondary plant succession. The main objective of this study was to investigate the ecological significance mycorrhizae, the symbiotic association between plant roots and specific fungi, may have during secondary plant succession. In 2004, we selected a chronosequence of five distinct stages of secondary succession ranging from recently disturbed areas to more mature forest at El Eden Ecological Reserve in northeastern Yucatan. We determined the plant community composition, as well as, the percent vesicular-arbuscular... https://escholarship.org/uc/item/63g6k6qx Tue, 2 Oct 2007 00:00:00 +0000 Niles J. Hasselquist Allen, Edith B Allen, Michael F. https://escholarship.org/uc/item/5xq4j015 <p>Abundances of <em>Pseudo-nitzschia</em> spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1500 km² were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles harbor (12.7 μg DA L⁻¹). Particulate DA levels were an order of magnitude lower in spring of 2004 (February and March), but DA concentrations per cell at several sampling stations during 2004 exceeded previously reported maxima for natural populations of <em>Pseudo-nitzschia</em> (mean = 24 pg DA cell⁻¹, range = 0–117 pg DA cell⁻¹). <em>Pseudo-nitzschia australis</em> dominated the <em>Pseudo-nitzschia</em> assemblage in spring 2004. Overall, DA-poisoning was implicated in &gt;1400 mammal stranding incidents... https://escholarship.org/uc/item/5xq4j015 Tue, 2 Oct 2007 00:00:00 +0000 Schnetzer, Astrid Miller, Peter E. Schaffner, Rebecca Stauffer, Beth Jones, Burton H. Weisberg, Stephen B. DiGiacomo, Paul M. Berelson, William M. Caron, David A. https://escholarship.org/uc/item/5vx6b93s <p>There exist many natural phenomena where direct measurement is either impossible or extremely invasive. To obtain approximate measurements of these phenomena we can build prediction models based on other sensing modalities such as features extracted from data collected by an imager. These models are derived from controlled experiments performed under laboratory conditions, and can then be applied to the associated event in nature. In this paper we explore various different methods for generating such models and discuss their accuracy, robustness, and computational complexity. Given sufficiently computationally simple models, we can eventually push their computation down towards the sensor nodes themselves to reduce the amount of data required to both flow through the network and be stored in a database. The addition of these models turn in-situ imagers into powerful biological sensors, and image databases into useful records of biological activity.</p> https://escholarship.org/uc/item/5vx6b93s Tue, 2 Oct 2007 00:00:00 +0000 Hyman, Josh Graham, Eric Hansen, Mark Estrin, D https://escholarship.org/uc/item/5vg6h5n0 <p>Energy-efficient image communication is one of the most important goals for a large class of current and future sensor network applications. This paper presents a quantitative comparison between the energy costs associated with 1) direct transmission of uncompressed images and 2) sensor platform-based JPEG compression followed by transmission of the compressed image data. JPEG compression computations are mapped onto various resource-constrained sensor platforms using a design environment that allows computation using the minimum integer and fractional bit-widths needed in view of other approximations inherent in the compression process and choice of image quality parameters. Detailed experimental results examining the tradeoffs in processor resources, processing/transmission time, bandwidth utilization, image quality, and overall energy consumption are presented.</p> https://escholarship.org/uc/item/5vg6h5n0 Tue, 2 Oct 2007 00:00:00 +0000 Lee, Dong-U Kim, Hyungjin Tu, Steven Rahimi, Mohammad Estrin, D Villasenor, John https://escholarship.org/uc/item/5t57f9d4 A Small Submarine Robot for Experiments in Underwater Sensor Networks https://escholarship.org/uc/item/5t57f9d4 Tue, 2 Oct 2007 00:00:00 +0000 V. Bokser C. Oberg G. Sukhatme A. Requicha https://escholarship.org/uc/item/5hp8j5sk <p>This paper describes a novel experiment in which two very different methods of underwater robot localization are compared. The first method is based on a geometric approach in which a mobile node moves within a field of static nodes, and all nodes are capable of estimating the range to their neighbours acoustically. The second method uses visual odometry, from stereo cameras, by integrating scaled optical flow. The fundamental algorithmic principles of each localization technique is described. We also present experimental results comparing acoustic localization with GPS for surface operation, and a comparison of acoustic and visual methods for underwater operation.</p> https://escholarship.org/uc/item/5hp8j5sk Tue, 2 Oct 2007 00:00:00 +0000 Corke, Peter Detwiler, Carrick Dunbabin, Matthew Hamilton, Michael Rus, Daniela Vasilescu, Iuliu https://escholarship.org/uc/item/5dk877x5 <p>In a wireless sensor network of <em>N</em> nodes transmitting data to a single base station, possibly over multiple hops, what distributed mechanisms should be implemented in order to dynamically allocate <em>fair</em> and <em>efficient</em> transmission rates to each node? Our interferenceaware fair rate control (IFRC) detects incipient congestion at a node by monitoring the average queue length, communicates congestion state to exactly the set of <em>potential interferers</em> using a novel low-overhead <em>congestion sharing</em> mechanism, and converges to a fair and efficient rate using an AIMD control law. We evaluate IFRC extensively on a 40-node wireless sensor network testbed. IFRC achieves a fair and efficient rate allocation that is within 20–40% of the optimal fair rate allocation on some network topologies. Its rate adaptation mechanism is highly effective: we did not observe a single instance of queue overflow in our many experiments. Finally, IFRC can be extended... https://escholarship.org/uc/item/5dk877x5 Tue, 2 Oct 2007 00:00:00 +0000 Rangwala, Sumit Gummadi, Ramakrishna Govindan, Ramesh Psounis, Konstantinos https://escholarship.org/uc/item/5br1t8tj <p>Scientists and engineers working with embedded networked sensing systems in the environmental sciences are acquiring data at unprecedented rates. Scientific data do not emerge from a vacuum. There is considerable contextual information that surrounds the process of data acquisition that is critical to interpret and analyze data. Current techniques for data sharing involve considerable manual effort to prepare, describe, and transfer this contextual information along with the data itself. This paper reports on a study of the UCLA-based Center for Embedded Networked Sensing (CENS), an interdisciplinary NSF research center that supports collaborations to develop and implement innovative wireless sensor networks. We report here on the development of the CENS Deployment Center, a database for CENS deployment information. The goals of the CENSDC are to facilitate better deployment organization, and to provide a central location for key information that describes the context of data... https://escholarship.org/uc/item/5br1t8tj Tue, 2 Oct 2007 00:00:00 +0000 Mayernik, Matthew Wallis, J C Borgman, C L Pepe, Alberto https://escholarship.org/uc/item/58b3k641 <p>In recent decades, the cost of acoustic technologies has declined dramatically. Advances in networks, storage devices, and power management have made it practical to consider the remote location of sensors. Nonetheless, many challenges remain for the fabrication, deployment, and use of remote sensors.</p><p>This paper provides an overview of the issues involved in developing remote acoustic sensors. We discuss physical design and the integration of components, data storage and communication issues, signal acquisition and classification, and the relationship of these issues to power usage requirements.</p> https://escholarship.org/uc/item/58b3k641 Tue, 2 Oct 2007 00:00:00 +0000 Girod, Lewis Roch, Marie A https://escholarship.org/uc/item/51n0073n Ad-Hoc Localization Using Ranging and Sectoring https://escholarship.org/uc/item/51n0073n Tue, 2 Oct 2007 00:00:00 +0000 K. Chintalapudi A. Dhariwal R. Govindan G.S. Sukhatme https://escholarship.org/uc/item/4xx221vv <p>For users to trust and interpret the data in scientific digital libraries, they must be able to assess the integrity of those data. Criteria for data integrity vary by context, by scientific problem, by individual, and a variety of other factors. This paper compares technical approaches to data integrity with scientific practices, as a case study in the Center for Embedded Networked Sensing (CENS) in the use of wireless, in-situ sensing for the collection of large scientific data sets. The goal of this research is to identify functional requirements for digital libraries of scientific data that will serve to bridge the gap between current technical approaches to data integrity and existing scientific practices.</p> https://escholarship.org/uc/item/4xx221vv Tue, 2 Oct 2007 00:00:00 +0000 Wallis, J C Borgman, C L Mayernik, Matthew Pepe, Alberto Ramanathan, Nithya Hansen, Mark https://escholarship.org/uc/item/4r48w3bb <p>In many sensing applications, including environmental monitoring, measurement systems must cover a large space with only limited sensing resources. One approach to achieve required sensing coverage is to use robots to convey sensors within this space.Planning the motion of these robots – coordinating their paths in order to maximize the amount of information collected while placing bounds on their resources (e.g., path length or energy capacity) – is a <strong>NP</strong>-hard problem. In this paper, we present an efficient path planning algorithm that coordinates multiple robots, each having a resource constraint, to maximize the “informativeness” of their visited locations. In particular, we use a Gaussian Process to model the underlying phenomenon, and use the mutual information between the visited locations and remainder of the space to characterize the amount of information collected. We provide strong theoretical approximation guarantees for our algorithm... https://escholarship.org/uc/item/4r48w3bb Tue, 2 Oct 2007 00:00:00 +0000 Singh, Amarjeet Krause, Andreas R. Guestrin, Carlos Kaiser, W J Batalin, Maxim https://escholarship.org/uc/item/4g43c9qv <p>The presence of arsenic in the groundwater has led to the largest environmental poisoning in history; tens of millions of people in the Ganges Delta continue to drink groundwater that is dangerously contaminated with arsenic. A current working hypothesis is that arsenic is mobilized in the near surface environment where sediments are weathered by seasonal changes in the redox state that drive a cycle of pyrite oxidation and iron oxide reduction. In order to test the supporting hypothesis that subsurface geochemical changes may be induced by agricultural activity, we deployed 42 wirelessly networked ion-selective electrodes, including calcium, ammonium, nitrate, ORP, chloride, carbonate, and pH in a rice paddy in the Munshiganj district of Bangladesh in January of 2006. Each sensor was connected to an MDA300 sensor board and Mica2 wireless transceiver and computational device. Over a period of 11 days, we observed clear diel, and diurnal trends in 4 of the electrodes (calcium,... https://escholarship.org/uc/item/4g43c9qv Tue, 2 Oct 2007 00:00:00 +0000 Ramanathan, Nithya Rothenberg, Sarah Estrin, D Harmon, T C Harvey, Charles Jay, J A Kohler, Eddie https://escholarship.org/uc/item/4fx9s0vn <p>Increasing demands on water supplies, non-point source pollution, and water quality-based ecological concerns all point to the need for observing stream flow perturbations and pollutant discharges at higher resolution than was practical in the past. This work presents the results from a test of a rapidly deployable river observational approach consisting of four components: (1) existing geospatial data and federal, state, and private river gauging infrastructure for identifying key river reaches and critical sampling times, (2) human- actuated sensor deployments for broad spatial characterization of the targeted river reach, (3) stationary sensors embedded in the river and its sediments for longer term spatiotemporal observations within the targeted reach, and (4) the robotic Networked Infomechanical System (NIMS RD) for high resolution scanning of spatiotemporal hydraulic and chemical properties at specific points along the reach. The approach is demonstrated for a test bed... https://escholarship.org/uc/item/4fx9s0vn Tue, 2 Oct 2007 00:00:00 +0000 Fisher, Jason Harmon, T C Kaiser, W J https://escholarship.org/uc/item/4db390pk <p>This paper introduces an adaptive sampling algorithm for a mobile sensor network to estimate a scalar field. The sensor network consists of static nodes and one mobile robot. The static nodes are able to take sensor readings continuously in place, while the mobile robot is able to move and sample at multiple locations. The measurements from the robot and the static nodes are used to reconstruct an underlying scalar field. The algorithm presented in this paper accepts the measurements made by the static nodes as inputs and computes a path for the mobile robot which minimizes the integrated mean square error of the reconstructed field subject to the constraint that the robot has limited energy. We assume that the field does not change when robot is taking samples. In addition to simulations, we have validated the algorithm on a robotic boat and a system of static buoys operating in a lake over several km of traversed distance while reconstructing the temperature field of the... https://escholarship.org/uc/item/4db390pk Tue, 2 Oct 2007 00:00:00 +0000 Zhang, Bin Sukhatme, Gaurav https://escholarship.org/uc/item/48p8j92g Array Processing of Acoustic and Vibrational Sources https://escholarship.org/uc/item/48p8j92g Tue, 2 Oct 2007 00:00:00 +0000 Yao, K https://escholarship.org/uc/item/44v6b3sj <p>Simple visible-light digital cameras offer a potential for expanded forms of plant ecological research. The moss Tortula princeps undergoes changes in reflected visible light during cycles of drying and hydrating in the field, and the MossCam project has collected digital images of T. princeps at least daily since 2003. Laboratory studies can be used to calibrate these images to indicate field physiological conditions. Drying the moss 6 d in the laboratory resulted in a decrease of net CO2 uptake to near 0; recovery after rewetting occurred within 10 min. The difference in reflectance between hydrated and dry T. princeps was maximal ca. 550 nm, and maximal net CO2 uptake was linearly related to the green : red ratio of laboratory images when net CO2 uptake was positive. Using the green : red ratio of field images and otherwise assuming ideal conditions, the total carbon gain for a 6-d period around a 1.3-mm rain event was ca. 208 mmol CO2 /m2, equivalent to 69 d of respiration... https://escholarship.org/uc/item/44v6b3sj Tue, 2 Oct 2007 00:00:00 +0000 Graham, Eric A Hamilton, Michael P Mishler, Brent D. Rundel, Philip W. Hansen, Mark H. https://escholarship.org/uc/item/44n870k0 <p>The position of the subducting Cocos Plate beneath Mexico is unknown from the Trans-Mexican Volcanic Belt (TMVB) northward. Geochemical analysis suggests that there may be a slab tear causing mafic volcanism along the northern edge of the (TMVB). An array of 100 seismometers at 5 km spacing is currently installed in Mexico by the MesoAmerican Seismic Experiment (MASE) in conjunction with the Center for Embedded Networked Sensing (CENS) at UCLA, the Universidad Nacional Autonoma de Mexico (UNAM), and the California Institute of Technology (CIS). The data from this array is used to develop P and S wave tomographies to locate the slab. Beneath the MASE line the Cocos plate dips from the trench to a ~ 50 km depth. It is almost subhorizontal between 110 km to 275 km from the trench at a ~50 km depth. Then it continues to dip at a near constant angle.</p> https://escholarship.org/uc/item/44n870k0 Tue, 2 Oct 2007 00:00:00 +0000 Husker, Allen Davis, Paul https://escholarship.org/uc/item/4354f19z <p>We have developed a new on-line error modeling and optimization-based localization approach for sensor networks in the presence of distance measurement noise. The approach is solely based on the concept of consistency, and is developed specifically for the case of on-line localization, which refers to the situation when references are not available a priori. The localization problem is formulated as the task of maximizing the consistency between measurements and calculated distances. In addition, we also present a localized localization algorithm where a specified communication cost or the location accuracy is guaranteed while optimizing the other. We evaluated the approach in (i) both GPS-based and GPS-less scenarios; (ii) 1-D, 2-D and 3-D spaces, on sets of acoustic ranging-based distance measurements recorded by deployed sensor networks. The experimental evaluation indicates that localization of only a few centimeters is consistently achieved when the average and median... https://escholarship.org/uc/item/4354f19z Tue, 2 Oct 2007 00:00:00 +0000 Feng, Jessica Girod, Lewis Potkonjak, Miodrag https://escholarship.org/uc/item/401090d7 <p>Wireless sensor networks research has, till date, made impressive advances in platforms and software services. Research in the area has moved on to consider an essential piece of sensor network technology—support for <em>programming</em> wireless sensor network applications and systems components at a suitably high level of abstraction. Two broad classes of programming models are currently being investigated by the community. One class focuses on providing higher-level abstractions for specifying a node's local behavior in a distributed computation. Examples of this approach include the recent work on node-local or region-based abstractions. By contrast, a second and less-explored class of research considers programming a sensor network in the large called <em>macroprogramming</em>.</p> https://escholarship.org/uc/item/401090d7 Tue, 2 Oct 2007 00:00:00 +0000 Gummadi, Ramakrishna Kothari, Nupur Millstein, Todd Govindan, Ramesh https://escholarship.org/uc/item/3zm539zd <p>An electrochemical system that consists of a silver electrode in 0.01 M sodium hydroxide electrolyte was investigated in an effort to develop a sensitive <em>in situ</em> analytical method for nitrate. Cyclic voltammetry demonstrated that the proposed system has a high normalized sensitivity (2.47 A s^½ V^−½ M⁻¹ cm⁻²), compared to more complex electroanalytical schemes. Double- potential-step chronocoulometry was used to maximize the signal-to-noise ratio (SNR), and minimize interference from dissolved oxygen in the electrolyte. The integration period for double- potential-step chronocoulometry was determined by optimizing the extended Cottrell equation. The integrated current is proportional to nitrate up to 10 mM and the average detection limit is approximately 1.7 µM. Dissolved oxygen does not degrade performance. To examine the potential interference of other ions when analyzing nitrate, we measured the electrode response to 1000 µM each of... https://escholarship.org/uc/item/3zm539zd Tue, 2 Oct 2007 00:00:00 +0000 Kim, Dohyun Goldberg, Ira B. Judy, J W https://escholarship.org/uc/item/3z79z6h6 A Comparison of Application-Level and Router-Assisted Hierarchical Schemes for Reliable Multicast https://escholarship.org/uc/item/3z79z6h6 Tue, 2 Oct 2007 00:00:00 +0000 Pavlin Radoslavov Christos Papadopoulos Ramesh Govindan Deborah Estrin https://escholarship.org/uc/item/3z34v3jd Preprocessing in a Tiered Sensor Network for Habitat Monitoring https://escholarship.org/uc/item/3z34v3jd Tue, 2 Oct 2007 00:00:00 +0000 H. Wang D. Estrin L. Girod https://escholarship.org/uc/item/3v00c698 <p>In this paper, we consider the analysis, implementation, and application of wideband sources using both seismic and acoustic sensors. We use the approximate maximum likelihood (AML) algorithm to perform acoustic direction of arrival (DOA). For non-uniform noise spectra, whitening filtering was applied to the received acoustic signals before the AML operation. For short-range seismic DOA applications, one method was based on eigen-decomposition of the covariance matrix and a second method was based on surface wave analysis. Two well-known optimization schemes were used to estimate the source locations from the estimated DOAs at sensors of known locations. Experimental estimation of the DOAs and resulting localizations using the acoustic and seismic signals generated by striking a heavy metal plate by a hammer were reported.</p> https://escholarship.org/uc/item/3v00c698 Tue, 2 Oct 2007 00:00:00 +0000 Stafsudd, J.Z Asgari, Shadnaz Chen, Chiao-En Hudson, Ralph E. Lorenzelli, F. Yao, K Taciroglu, Ertugrul https://escholarship.org/uc/item/3fm5v6hp Computing Aggregates for Monitoring Wireless Sensor Networks https://escholarship.org/uc/item/3fm5v6hp Tue, 2 Oct 2007 00:00:00 +0000 Yonggang Jerry Zhao Ramesh Govindan Deborah Estrin https://escholarship.org/uc/item/3fj6g58j Localized Edge Detection in Sensor Fields https://escholarship.org/uc/item/3fj6g58j Tue, 2 Oct 2007 00:00:00 +0000 K. Chintalapudi R. Govindan https://escholarship.org/uc/item/39n6q2xv <p>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.</p> https://escholarship.org/uc/item/39n6q2xv Tue, 2 Oct 2007 00:00:00 +0000 Browne, David W. Loo, Chris Ha, Jesen Borgstrom, Henrik Fitz, M P Kaiser, W J Valerie Bick Katherine Kuan Eric Seidler Haleh Tabrizi https://escholarship.org/uc/item/37c6q31b <p>Harmful brown tides caused by the pelagophyte <em>Aureococcus anophagefferens</em> have occurred in mid-Atlantic estuaries for 2 decades. Low grazing rates by microzooplankton have been implicated as a possible cause of these events, but no study to date has concurrently quantified zooplankton population densities and zooplankton grazing rates of <em>A. anophagefferens</em> cells. We conducted field studies from 2002 to 2004 to quantify grazing on the brown tide alga <em>A. anophagefferens</em> by meso-, micro-, and nanozooplankton, while concurrently establishing the composition of the plankton community. Research sites included an estuary that experienced an intense brown tide (Chincoteague Bay, Maryland [MD]; 2004: 2 × 10⁶ cells ml⁻¹) and one that experienced sporadic blooms (Quantuck Bay, New York [NY]; 2002: 8 × 10⁵ cells ml⁻¹; 2003 and 2004: × 10⁴ cells ml⁻¹). The MD site was dominated by small autotrophs (µm), such as <em>A. anophagefferens</em> and other picoeukaryotes,... https://escholarship.org/uc/item/37c6q31b Tue, 2 Oct 2007 00:00:00 +0000 Sarah N. Deonarine Gobler, Christopher J. Lonsdale, Darcy J. Caron, David A. https://escholarship.org/uc/item/31f765tj <p>Various sensor network measurement studies have reported instances of transient faults in sensor readings. In this work, we seek to answer a simple question: How often are such faults observed in real deployments? To do this, we first explore and characterize three qualitatively different classes of fault detection methods. Rule-based methods leverage domain knowledge to develop heuristic rules for detecting and identifying faults. Estimation methods predict "normal" sensor behavior by leveraging sensor correlations, flagging anomalous sensor readings as faults. Finally, learning-based methods are trained to statistically identify classes of faults. We find that these three classes of methods sit at different points on the accuracy/robustness spectrum. Rule-based methods can be highly accurate, but their accuracy depends critically on the choice of parameters. Learning methods can be cumbersome, but can accurately detect and classify faults. Estimation methods are accurate,... https://escholarship.org/uc/item/31f765tj Tue, 2 Oct 2007 00:00:00 +0000 Sharma, Abhishek Golubchik, Leana Govindan, Ramesh https://escholarship.org/uc/item/2sb5k256 <p>Tiered sensor network architectures are gaining currency. In contrast with flat networks of impoverished nodes (the hitherto common assumption in sensor networking), such systems offer the promise of migrating computational load from sensing nodes to higher capability ‘master’ nodes. We argue that for certain data fusion-based services this means that compute intensive algorithms, often shunned as impractical for sensor networks, are in fact a viable possibility. Using localization as an example, we show how accurate results may be obtained by leveraging this capability without the use of specialized hardware or high configuration detail; both of which are standard approaches to the problem when computation is at a premium. Specifically, we propose a mathematical optimization-based framework for localization based on proximity constraints. Most variants of localization can be cast into this framework depending on the kinds of input available (e.g. ranging).... https://escholarship.org/uc/item/2sb5k256 Tue, 2 Oct 2007 00:00:00 +0000 Dantu, Karthik Sukhatme, Gaurav https://escholarship.org/uc/item/2h08k1xm Region-based segmentation on evolving surfaces with application to 3D shape and radiance estimation https://escholarship.org/uc/item/2h08k1xm Tue, 2 Oct 2007 00:00:00 +0000 H. Jin A. J. Yezzi S. Soatto https://escholarship.org/uc/item/2fx7s5zq <p>Wave-propagation effects can be useful in determining the system identification of buildings such as the densely instrumented University of California, Los Angeles, Factor building. Waveform data from the 72-channel array in the 17-story moment-resisting steel frame Factor building are used in comparison with finite- element calculations for predictive behavior. The high dynamic range of the 24-bit digitizers allows both strong motions and ambient vibrations to be recorded with reasonable signal-to-noise ratios. A three-dimensional model of the Factor building has been developed based on structural drawings. Observed displacements for 20 small and moderate, local and regional earthquakes were used to compute the impulse response functions of the building by deconvolving the subbasement records as representative input motions at its base. The impulse response functions were then stacked to bring out wave-propagation effects more clearly. The stacked data are used as input into... https://escholarship.org/uc/item/2fx7s5zq Tue, 2 Oct 2007 00:00:00 +0000 Kohler, Monica Heaton, Thomas H. Samuel C. Bradford https://escholarship.org/uc/item/22j1w3x8 <p>Missing data is unavoidable in sensor networks due to sensor faults, communication malfunctioning and malicious attacks. There is a very little insight in missing data causes and statistical and pattern properties of missing data in collected data streams. To address this problem, we utilize interacting-particle model that takes into account both patterns of missing data at individual sensor data streams as well as the correlation between occurrence of missing data at other sensor data streams. The model can be used in algorithms and protocols for energy efficient data collection and other tasks in presence of missing data.</p><p>We use statistical intersensor models for predicting the readings of different sensors. As a driver application, we address the problem of energy efficient sensing by adaptively coordinating the sleep schedules of sensor nodes while we guarantee that values of nodes in the sleep mode can be recovered from the awake nodes within a user’s specified error... https://escholarship.org/uc/item/22j1w3x8 Tue, 2 Oct 2007 00:00:00 +0000 Koushanfar, Farinaz Kiyavash, Negar Potkonjak, Miodrag https://escholarship.org/uc/item/2059b99k <p>To understand the complex interactions among animals within an ecosystem, biologists need to be able to track their location and social interactions. There are a variety of factors that make this difficult. We propose using adaptive, embedded networked sensing technologies to develop an efficient means for wildlife monitoring. This paper surveys our research; we demonstrate how a self-organizing system can efficiently conduct real-time acoustic source detection and localization using distributed embedded devices.</p> https://escholarship.org/uc/item/2059b99k Tue, 2 Oct 2007 00:00:00 +0000 Trifa, Vlad Girod, Lewis Collier, Travis C. Blumstein, Daniel Taylor, C E https://escholarship.org/uc/item/1s30z37r RMST: Reliable Data Transport in Sensor Networks https://escholarship.org/uc/item/1s30z37r Tue, 2 Oct 2007 00:00:00 +0000 Fred Stann John Heidemann https://escholarship.org/uc/item/1q69505n <p>Advances in DSP technology create important avenues of research for embedded vision. One such avenue is the investigation of tradeoffs amongst system parameters which affect the energy, accuracy, and latency of the overall system. This paper reports work on benchmarking the performance and cost of Scale Invariant Feature Transform (SIFT) for visual classification on a Blackfin DSP processor. Through measurements andmodeling of the camera sensor node, we investigate system performance (classification accuracy, latency, energy consumption) in light of image resolution, arithmetic precision, location of processing (local vs. server-side), and processor speed. A case study on counting eggs during avian nesting season is used to experimentally determine the tradeoffs of different design parameters and discuss implications to other application domains.</p> https://escholarship.org/uc/item/1q69505n Tue, 2 Oct 2007 00:00:00 +0000 Ko, Teresa Charbiwala, Zainul Mohammed Ahmadian, Shaun Rahimi, Mohammed Srivastava, Mani B. Soatto, Stefano Estrin, D https://escholarship.org/uc/item/1km520ps Embedded Networked Sensing in Terrestrial Ecosystems https://escholarship.org/uc/item/1km520ps Tue, 2 Oct 2007 00:00:00 +0000 Hamilton, Michael https://escholarship.org/uc/item/1hq4921q Target Classification and Localization in Habitat Monitoring https://escholarship.org/uc/item/1hq4921q Tue, 2 Oct 2007 00:00:00 +0000 H. Wang J. Elson L. Girod D. Estrin K. Yao L. Vanderberge https://escholarship.org/uc/item/1df5m8g6 <p>We have developed a new error modeling and optimization-based localization approach for sensor networks in presence of distance measurement noise. The approach is solely based on the concept of consistency. The error models are constructed using non-parametric statistical techniques; they do not only indicate the most likely error, but also provide the likelihood distribution of particular errors occurring. The models are evaluated using the learn-and-test techniques and serve as the objective functions for the task of localization. The localization problem is formulated as task of maximizing consistency between measurements and calculated distances. We evaluated the approach in (i) both GPS-based and GPS-less scenarios; (ii) 1-D, 2-D and 3-D spaces, on sets of acoustic ranging-based distance measurements recorded by deployed sensor networks. The experimental evaluation indicates that localization of only a few centimeters is consistently achieved when the average and median... https://escholarship.org/uc/item/1df5m8g6 Tue, 2 Oct 2007 00:00:00 +0000 Feng, Jessica Potkonjak, Miodrag https://escholarship.org/uc/item/13r0q4fc <p>Embedded microcontrollers are becoming increasingly prolific, serving as the primary or auxiliary processor in products and research systems from microwaves to sensor networks. Microcontrollers represent perhaps the most severely resource-constrained embedded processors, often with as little as a few bytes of memory and a few kilobytes of code space. Language and compiler technology has so far been unable to bring the benefits of modern object-oriented languages to such processors. In this paper, I will present the design and implementation of Virgil, a lightweight object-oriented language designed with careful consideration for resource-limited domains. Virgil explicitly separates <em>initialization time</em> from runtime, allowing an application to build complex data structures during compilation and then run directly on the bare hardware without a virtual machine or any language runtime. This separation allows the entire program heap to be available at compile time and enables... https://escholarship.org/uc/item/13r0q4fc Tue, 2 Oct 2007 00:00:00 +0000 Titzer, B L https://escholarship.org/uc/item/1190s0xj <p>We present distributed algorithms for sensor localization based on the Gauss-Newton method. Each sensor updates its estimated location by computing the Gauss-Newton step for a local cost function and choosing a proper step length. Then it transmits the updated estimate to all the neighboring sensors. The proposed algorithms provide non-increasing values of a global cost function. It is shown in the paper that the algorithms have computational complexity of O(n) per iteration and a reduced communication cost over centralized algorithms.</p> https://escholarship.org/uc/item/1190s0xj Tue, 2 Oct 2007 00:00:00 +0000 Cheng, Bing Hwa Hudson, Ralph E. Lorenzelli, F. Vandenberghe, Lieven Yao, K https://escholarship.org/uc/item/10k610k2 DIFS: A Distributed Index for Features in Sensor Networks https://escholarship.org/uc/item/10k610k2 Tue, 2 Oct 2007 00:00:00 +0000 Benjamin Greenstein Deborah Estrin Ramesh Govindan Sylvia Ratnasamy Scott Shenker https://escholarship.org/uc/item/0zw6q9jf Performance Aware Tasking for Environmentally Powered Sensor Networks https://escholarship.org/uc/item/0zw6q9jf Tue, 2 Oct 2007 00:00:00 +0000 A. Kansal D. Potter MB Srivastava https://escholarship.org/uc/item/0x20w1b8 <p>This paper describes the design, development, and initial application of a sensor-actuated network for sensing and sampling microbial communities in aquatic ecosystems. The network consists of ten stationary buoys and one mobile robotic boat for real-time, <em>in situ</em> measurements and analysis of chemical and physical factors governing the abundance and dynamics of microorganisms at biologically relevant spatiotemporal scales. The goal of the network is to obtain high-resolution information on the spatial and temporal distributions of plankton assemblages and concomitant environmental parameters in aquatic environments using the <em>in situ</em> presence afforded by the network and to make possible network-enabled robotic sampling of hydrographic features of interest. This work constitutes advances in (1) real-time observing in aquatic ecosystems and (2) sensor actuated sampling for biological analysis.</p> https://escholarship.org/uc/item/0x20w1b8 Tue, 2 Oct 2007 00:00:00 +0000 Sukhatme, Gaurav Dhariwal, Amit Zhang, Bin Oberg, Carl Stauffer, Beth Caron, David A.