David E. Culler

David E. Culler
University of California, Berkeley | UCB · Computer Science Division

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418
Publications
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Publications

Publications (418)
Article
There is now a significant and growing functional gap between the public Internet, whose basic architecture has remained unchanged for several decades, and a new generation of more sophisticated private networks. To address this increasing divergence of functionality and overcome the Internet's architectural stagnation, we argue for the creation of...
Conference Paper
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Can cloud computing infrastructures provide HPC-competitive performance for scientific applications broadly? Despite prolific related literature, this question remains open. Answers are crucial for designing future systems and democratizing high-performance computing. We present a multi-level approach to investigate the performance gap between HPC...
Preprint
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Large scale modeling and simulation problems, from nanoscale materials to universe-scale cosmology, have in the past used the massive computing resources of High-Performance Computing (HPC) systems. Over the last decade, cloud computing has gained popularity for business applications and increasingly for computationally intensive machine learning p...
Preprint
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Governments around the world have become increasingly frustrated with tech giants dictating public health policy. The software created by Apple and Google enables individuals to track their own potential exposure through collated exposure notifications. However, the same software prohibits location tracking, denying key information needed by public...
Article
Full-text available
We present PC-RPL, a transmission power-controlled IPv6 routing protocol for low-power and lossy wireless networks (LLNs) that significantly improves the end-to-end packet delivery performance under heavy traffic, compared to the standard RPL. We show through actual design, implementation, and experiments that a multihop wireless network can achiev...
Article
The Heating Ventilation and Air Conditioning (HVAC) system of commercial buildings traditionally runs on a fixed schedule that does not take occupancy into account despite its huge variation over space and time, thereby wasting a lot of energy in conditioning empty or partially-occupied spaces. Occupancy information is essential to eliminate wastef...
Article
Buildings account for 32% of worldwide energy usage. A new regime of exciting new “applications” that span a distributed fabric of sensors, actuators and humans has emerged to improve building energy efficiency and operations management. These applications leverage the technological advances in embedded sensing, processing, networking and methods b...
Article
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With the increasing commoditization of computer vision, speech recognition and machine translation systems and the widespread deployment of learning-based back-end technologies such as digital advertising and intelligent infrastructures, AI (Artificial Intelligence) has moved from research labs to production. These changes have been made possible b...
Article
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As the number and heterogeneity of appliances in smart buildings increases, identifying and controlling them becomes challenging. Existing methods face various challenges when deployed in large commercial buildings. For example, voice command assistants require users to memorize many control commands. Attaching Bluetooth dongles or QR codes to appl...
Conference Paper
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Operating buildings can be challenging, especially with poor instru-mentation of the indoor environment. There are several wireless sensor platforms on the market but most are too difficult to deploy en-masse, requiring the end-user to program devices, or manage infrastructure. Many rely on smart-phones and do not work when unattended. The Hamilton...
Article
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RPL is the IPv6 routing protocol for low-power and lossy networks (LLNs), standardized by IETF in 2012 as RFC6550. Specifically, RPL is designed to be a simple and inter-operable networking protocol for resource-constrained devices in industrial, home, and urban environments, intended to support the vision of the Internet of Things (IoT) with thous...
Conference Paper
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We show that a multihop wireless network can achieve better bandwidth and routing stability when transmission power and routing topology are jointly and adaptively controlled. Our experiments show that the predominant 'fixed and uniform' transmission power strategy with 'link quality and hop distance'-based routing topology construction loses signi...
Article
I am often asked these days, "Is IoT really as transformative as all the buzz suggests, or is it a lot of hype?" My answer is simply, "Yes." And the road to here has been a fascinating interplay of academic research accomplishments, industry advances (often with other drivers), and standardization processes (for lack of a better term). It was predi...
Conference Paper
The design of energy-efficient commercial building Heating Ventilation and Air Conditioning (HVAC) systems has been in the forefront of energy conservation efforts over the past few decades. The HVAC systems traditionally run on a static schedule that does not take occupancy into account, wasting a lot of energy in conditioning empty or partially-o...
Conference Paper
Full-text available
Sensorized commercial buildings are a rich target for building a new class of applications that improve operational and energy efficiency of building operations that take into account human activities. Such applications, however, rarely experience widespread adoption due to the lack of a common descriptive schema that would enable porting these app...
Conference Paper
Commercial buildings have long since been a primary target for applications from a number of areas: from cyber-physical systems to building energy use to improved human interactions in built environments. While technological advances have been made in these areas, such solutions rarely experience widespread adoption due to the lack of a common desc...
Article
Full-text available
To enable a prosperous Internet of Things (IoT), devices and services must be extensible and adapt to changes in the environment or user interaction patterns. These requirements manifest as a set of design principles for each of the layers in an IoT ecosystem, from hardware to cloud services. This paper gives concrete guidelines learned from implem...
Conference Paper
Carpooling has been long deemed a promising approach to better utilizing existing transportation infrastructure. However, there are several reasons carpooling is still not the preferred mode of commute in the United States: first, complex human factors, including time constraints and not having right incentive structures, discourage the sharing of...
Conference Paper
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In Building Automation Systems contextual information about sensors is frequently missing or hard-coded in the control code. Retrieving this data is time consuming and error-prone, but necessary to write any type of control application. Automating metadata acquisition is a new and active area of research. Methods to infer metadata from sensor label...
Conference Paper
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Commercial buildings account for a large amount of delivered energy in the U.S., nearly 42% of which is consumed in buildings with digital control systems {EIA}. These buildings are a ripe venue to deploy novel applications because of (a) access to sensors and actuators that are used in their digital control systems, (b) deployed wireless sensor ne...
Conference Paper
We present XBOS, an eXtensible Building Operating System for integrated management of previously isolated building subsystems. The key contribution of XBOS is the Building Profile, a canonical, executable description of a building and its subsystems that changes with a building and evolves control processes and applications accordingly. The design...
Conference Paper
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Personal Comfort Systems (PCS) are capable of maintaining occupant comfort in buildings despite large deviations from recommended "comfortable" temperatures. We present a novel digital controller for a well-studied (previously analog) PCS, allowing it to report real-time telemetry and respond to programmatic actuation requests. This enables the est...
Conference Paper
Commercial buildings consume nearly 19\% of delivered energy in the U.S, nearly half (42%) of which is consumed in buildings with digital control systems comprised of wired sensor networks. These sensors have scant metadata, and are represented by ``tags'' which are obscure, building-specific and not machine parseable. We develop a human-in-the-loo...
Conference Paper
The introduction and deployment of cheap, high precision, high-sample-rate next-generation synchrophasors en masse in both the transmission and distribution tier — while invaluable for event diagnosis, situational awareness and capacity planning — poses a problem for existing methods of phasor data analysis and storage. Addressing this, we present...
Conference Paper
Syntax-guided synthesis searches for an implementation of a given specification by exploring large spaces of candidate programs. Sketches reduce these search spaces, making synthesis more tractable, by predefining the structure of the desired implementation. Typically, this structure is obtained through human insight---this paper introduces a metho...
Conference Paper
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Rust, a new systems programming language, provides compile-time memory safety checks to help eliminate runtime bugs that manifest from improper memory management. This feature is advantageous for operating system development, and especially for embedded OS development, where recovery and debugging are particularly challenging. However, embedded pla...
Conference Paper
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Information technology can increase energy efficiency by improving the control of energy-using devices and systems. Awareness of this potential is not new—ideas for applications of information technology for energy efficiency have been promoted for more than 20 years. But much of the potential gain from the application of information technology has...
Conference Paper
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Many indoor localization algorithms have been proposed to enable location-based applications in indoor environments. However, these systems are monolithic and not component-based. We present BearLoc, a distributed modular framework for indoor localization systems that provides (1) natural development abstractions for sensor, algorithm, and applicat...
Conference Paper
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For the last fifteen years, research explored the hardware, software, sensing, communication abstractions, languages, and protocols that could make networks of small, embedded devices-motes-sample and report data for long periods of time unattended. Today, the application and technological landscapes have shifted, introducing new requirements and n...
Conference Paper
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In this demonstration, we present a novel system of building control and simulation focused on the integration of the physical and virtual worlds. Actuations and schedules can be manifested either in a physical space or in a virtualization of that space, allowing for more natural interactions with simulations and easier transferring of schedules an...
Conference Paper
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Sensor network research has facilitated advancements in various domains, such as industrial monitoring, environmental sensing, etc., and research challenges have shifted from creating infrastructure to utilizing it. Extracting meaningful information from sensor data, or control applications using the data, depends on the metadata available to inter...
Conference Paper
Full-text available
Extracting meaningful information from a building's sensor data, or writing control applications using the data, depends on the metadata available to interpret it, whether provided by novel networks or legacy instrumentation. Commercial buildings comprise large sensor networks, but have limited, obscure 'tags' that are often meaningful only to the...
Article
We present nesC, a programming language for networked embedded systems that represent a new design space for application developers. An example of a networked embedded system is a sensor network, which consists of (potentially) thousands of tiny, lowpower "motes," each of which execute concurrent, reactive programs that must operate with severe mem...
Article
Building power proportional High Performance Computing (HPC) clusters comprising of servers which are not power-proportional is a well-studied problem, and has the potential to provide large energy savings. However, a large emphasis on maintaining cluster uptime disincentivizes system administrators from deploying prior research techniques that int...
Conference Paper
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This paper describes a research project to develop a network of high-precision phasor measurement units, termed micro-synchrophasors or μPMUs, and explore the applications of μPMU data for electric power distribution systems.
Article
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In this paper, we model energy use in commercial buildings using empirical data captured through sMAP, a campus building data portal at UC Berkeley. We conduct at-scale experiments in a newly constructed building on campus. By modulating the supply duct static pressure (SDSP) for the main supply air duct, we induce a response on the main supply fan...
Conference Paper
Full-text available
Most large, commercial buildings contain thousands of sensors that are manually deployed and managed. These sensors are used by software and firmware processes to analyze and control building operations. Many such processes rely on sensor placement information in order to perform correctly. However, as buildings evolve and building subsystems grow...
Conference Paper
The system is environment monitoring service based on Wireless Sensor Networks (WSN). Users can know temperature, humidity, light, and CO2 level in real time. Excessive electricity consumption by lighting in the office can be saved and the quality of the office environment can become better by controlling lighting and CO2 level.
Conference Paper
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We develop a flexible and responsive electrical load in the form of domestic refrigerators augmented with a thermal storage system, a wireless sensor network for monitoring and actuation, and a controller that enables response to external controls. Using this, we investigate the potential of such loads for two applications: price-responsive demand...
Conference Paper
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Electricity grids are transforming as renewables proliferate, yet operational concerns due to fluctuations in renewables sources could limit the ultimate potential for high penetrations of renewables. In this paper, we compare three electricity grids - California, Germany, and Ontario - studying the effects of relative cost of solar and wind genera...
Conference Paper
There has been a recent industrial effort to develop multi-resource hierarchical schedulers. However, the existing implementations have some shortcomings in that they might leave resources unallocated or starve certain jobs. This is because the multi-resource setting introduces new challenges for hierarchical scheduling policies. We provide an algo...
Article
Data centers can lower costs significantly by provisioning expensive electrical equipment (such as UPS, diesel generators, and cooling capacity) for the actual peak power consumption rather than server nameplate power ratings. However, it is possible that this under-provisioned power level is exceeded due to software behaviors on rare occasions and...
Conference Paper
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There is enormous potential for building-focused applications to improve operation and sustainability, both for classical uses like modeling or fault detection as well as innovative ones like occupant-driven control or grid-aware energy management. We show that a building application stack - that addresses shortcomings of existing antiquated archit...
Conference Paper
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Mapping sidewalks in urban environments is key in the creation of pedestrian-friendly, sustainable cities. Currently, urban planners are hindered by a lack of information available in a format suitable for the large-scale analysis of sidewalk design. To demonstrate the impact that information technology could have in this area, we leverage techniqu...
Article
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A typical large building contains thousands of sensors, monitoring the HVAC system, lighting, and other operational sub-systems. With the increased push for operational efficiency, operators are relying more on historical data processing to uncover opportunities for energy-savings. However, they are overwhelmed with the deluge of data and seek more...
Conference Paper
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Commercial buildings are attractive targets for introducing innovative cyber-physical control systems, because they are already highly instrumented distributed systems which consume large quantities of energy. However, they are not currently programmable in a meaningful sense because each building is constructed with vertically integrated, closed s...
Conference Paper
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We develop a vignette of an information-rich energy network with flexible and responsive electrical loads in the form of a domestic refrigerator augmented with a thermal storage system and a supply-following controller that responds to the availability of fluctuating renewable sources. We fully characterize our prototype thermal storage-enhanced re...
Conference Paper
Through accurate and dynamic occupancy detection, building actuation systems can fine tune the targets of their actions to better fit the patterns of usage in modern buildings. We outline a method for achieving this through existing wireless infrastructure and present a demonstration of its viability in a corporate environment.
Conference Paper
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In this paper we present a system called the Energy Lens -- a system that provides deeper, real-time visibility of plug-load energy consumption in buildings. Our initial work focuses on plug-load power metering, display, and real-time aggregation, presented to the user through a mobile phone. We discuss the three main, non-trivial challenges that m...
Conference Paper
Many commercial buildings have digital controls and extensive sensor networks that can be used to develop novel applications for saving energy, detecting faults, improving comfort, etc. However, buildings are custom designed, leading to differences in functionality, connectivity, controls and operation. As a result today's building applications are...
Article
Full-text available
In the US buildings consume 70% of electricity, but the sector exhibits little innovation for reducing its consumption. Efficiency is not yet evaluated to the same standard as comfort and reliability, but with better user input, control policy, and awareness of the building's state, energy consumption can be intelligently reduced. It is argued that...
Article
Micro-solar power system design is challenging because it must address long-term system behavior under highly variable solar energy conditions and consider a large space of design options. Several micro-solar power systems and models have been made, validating particular points in the whole design space. We provide a general architecture of micro-s...
Conference Paper
Heating, ventilation, and air-conditioning (HVAC) systems use a large amount of energy, and so they are an interesting area for efficiency improvements. The focus here is on the use of semiparametric regression to identify models, which are amenable to analysis and control system design, of HVAC systems. This paper briefly describes two testbeds th...
Article
It is often highly valuable for organizations to have their data analyzed by external agents. However, any program that computes on potentially sensitive data risks leaking information through its output. Differential privacy provides a theoretical framework for processing data while protecting the privacy of individual records in a dataset. Unfort...
Article
A flurry of recent work has examined the interaction between system design and power optimization, with the promise of energy savings. We find that the power consumed by current commodity hardware can be well-approximated by a model with two components: a large always-present constant power and a linear power-performance tradeoff. As a result, many...
Article
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We present insights obtained from conducting a year-long, 455 meter deployment of wireless plug-load electric meters in a large commercial building. We develop a stratified sampling methodology for surveying the energy use of Miscellaneous Electric Loads (MELs) in commercial buildings, and apply it to our study building. Over the deployment period,...
Article
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Experimentally comparing the energy usage and comfort characteristics of different controllers in heating, ventilation, and air-conditioning (HVAC) systems is difficult because variations in weather and occupancy conditions preclude the possibility of establishing equivalent experimental conditions across the order of hours, days, and weeks. This p...
Article
Full-text available
Improving the energy-efficiency of heating, ventilation, and air-conditioning (HVAC) systems has the potential to realize large economic and societal benefits. This paper concerns the system identification of a hybrid system model of a building-wide HVAC system and its subsequent control using a hybrid system formulation of learning-based model pre...
Conference Paper
Buildings are some of the largest energy consumers in the world and yet occupants are regularly dissatisfied with the interior environment in large part due to thermal discomfort [7]. Studies show that given personal control over their environment, occupants are comfortable in a much larger range of ambient temperatures [2]. We present a personaliz...
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Cyber-Physical Systems (CPS) are characterized as complex distributed systems exhibiting substantial uncertainty due to interactions with the physical world. Today's electric grids are often described as CPS because a portfolio of distributed supplies must be dispatched in real-time to match uncontrolled, uncertain demand while adhering to constrai...
Article
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Heating, ventilation, and air conditioning (HVAC) systems are an important target for efficiency improvements through new equipment and retrofitting because of their large energy footprint. One type of equipment that is common in homes and some offices is an electrical, single-stage heat pump air conditioner (AC). To study this setup, we have built...
Conference Paper
Interoperability is key to widespread adoption of sensor network technology, but interoperable systems have traditionally been difficult to develop and test. We demonstrate an interoperable system development and performance diagnosis environment in which different systems, different software, and different hardware can be simulated in a single net...
Conference Paper
Full-text available
Interoperability is essential for the commercial adoption of wireless sensor networks. However, existing sensor network architectures have been developed in isolation and thus interoperability has not been a concern. Recently, IP has been proposed as a solution to the interoperability problem of low-power and lossy networks (LLNs), considering its...
Article
Miscellaneous and electronic loads (MELs) consume about 30% of the electricity used in U.S. commercial buildings, but our understanding of their energy use lags the traditional end-uses. A key component of reducing energy use is understanding how devices are used, but few studies have collected field data on the long-term energy used by a large sam...