Ramesh Govindan

Ramesh Govindan
University of Southern California | USC · Department of Computer Science

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208
Publications
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25,362
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Publications

Publications (208)
Preprint
Full-text available
Autonomous driving will become pervasive in the coming decades. iDriving improves the safety of autonomous driving at intersections and increases efficiency by improving traffic throughput at intersections. In iDriving, roadside infrastructure remotely drives an autonomous vehicle at an intersection by offloading perception and planning from the ve...
Article
Public outdoor surveillance cameras often have limited metadata describing their properties. Frequently, a public camera’s precise position, orientation, focal length, and image center are unknown; these attributes are necessary to precisely pinpoint the location of events seen in the camera. In this article, we ask: what is the minimal information...
Preprint
Full-text available
Autonomous vehicles use 3D sensors for perception. Cooperative perception enables vehicles to share sensor readings with each other to improve safety. Prior work in cooperative perception scales poorly even with infrastructure support. AutoCast enables scalable infrastructure-less cooperative perception using direct vehicle-to-vehicle communication...
Article
While most networks have long lifetimes, temporary network infrastructure is often useful for special events, pop-up retail, or disaster response. An instant IoT network is one that is rapidly constructed, used for a few days, then dismantled. We consider the synthesis of instant IoT networks in urban settings. This synthesis problem must satisfy c...
Preprint
Labeling a data set completely is important for groundtruth generation. In this paper, we consider the problem of minimum-cost labeling: classifying all images in a large data set with a target accuracy bound at minimum dollar cost. Human labeling can be prohibitive, so we train a classifier to accurately label part of the data set. However, traini...
Preprint
Full-text available
Public cameras often have limited metadata describing their attributes. A key missing attribute is the precise location of the camera, using which it is possible to precisely pinpoint the location of events seen in the camera. In this paper, we explore the following question: under what conditions is it possible to estimate the location of a camera...
Preprint
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Advances in optimization and constraint satisfaction techniques, together with the availability of elastic computing resources, have spurred interest in large-scale network verification and synthesis. Motivated by this, we consider the top-down synthesis of ad-hoc IoT networks for disaster response and search and rescue operations. This synthesis p...
Preprint
Cashier-free shopping systems like Amazon Go improve shopping experience, but can require significant store redesign. In this paper, we propose Grab, a practical system that leverages existing infrastructure and devices to enable cashier-free shopping. Grab needs to accurately identify and track customers, and associate each shopper with items he o...
Preprint
The popularity of photo sharing services has increased dramatically in recent years. Increases in users, quantity of photos, and quality/resolution of photos combined with the user expectation that photos are reliably stored indefinitely creates a growing burden on the storage backend of these services. We identify a new opportunity for storage sav...
Conference Paper
Video dominates Internet traffic today. Users retrieve on-demand video from Content Delivery Networks (CDNs) which cache video chunks at front-ends. In this paper, we describe AViC, a caching algorithm that leverages properties of video delivery, such as request predictability and the presence of highly unpopular chunks. AViC's eviction policy expl...
Conference Paper
Full-text available
Detecting activities from video taken with a single camera is an active research area for ML-based machine vision. In this paper, we examine the next research frontier: near real-time detection of complex activities spanning multiple (possibly wireless) cameras, a capability applicable to surveillance tasks. We argue that a system for such complex...
Article
With internet video gaining increasing popularity and soaring to dominate network traffic, extensive studies are being carried out on how to achieve higher Quality of Experience (QoE) with the delivery of video content. Associated with the chunk-based streaming protocol, Adaptive Bitrate (ABR) algorithms have recently emerged to cope with the diver...
Article
Autonomous vehicle prototypes today come with line-of-sight depth perception sensors like 3D cameras. These 3D sensors are used for improving vehicular safety in autonomous driving, but have fundamentally limited visibility due to occlusions, sensing range, and extreme weather and lighting conditions. To improve visibility and performance, we explo...
Conference Paper
Deep neural networks (DNNs) are emerging as important drivers for GPU (Graphical Processing Unit) usage. Routinely, now, cloud offerings include GPU-capable VMs, and GPUs are used for training and testing DNNs. A popular way to run inference (or testing) tasks with DNNs is to use middleware called a serving system. Tensorflow-Serving (TF-Serving) i...
Preprint
The democratization of machine learning (ML) has led to ML-based machine vision systems for autonomous driving, traffic monitoring, and video surveillance. However, true democratization cannot be achieved without greatly simplifying the process of collecting groundtruth for training and testing these systems. This groundtruth collection is necessar...
Conference Paper
While Internet video control and data planes have received much research attention, little is known about the video management plane. In this paper, using data from more than a hundred video publishers spanning two years, we characterize the video management plane and its evolution. The management plane shows significant diversity with respect to v...
Conference Paper
Most content providers are interested in providing good video delivery QoE for all users, not just on average. State-of-the-art ABR algorithms like BOLA and MPC rely on parameters that are sensitive to network conditions, so may perform poorly for some users and/or videos. In this paper, we propose a technique called Oboe to auto-tune these paramet...
Conference Paper
Accurate positioning in urban areas is important for personal navigation, geolocation apps, and ride-sharing. Smartphones localize themselves using GPS position estimates, and augment these with a variety of techniques including dead reckoning, map matching, and WiFi localization. However, GPS signals suffer significant impairment in urban canyons...
Conference Paper
Full-text available
Autonomous vehicle prototypes today come with line-of-sight depth perception sensors like 3D cameras. These 3D sensors are used for improving vehicular safety in autonomous driving, but have fundamentally limited visibility due to occlusions, sensing range, and extreme weather and lighting conditions. To improve visibility and performance, not just...
Article
Full-text available
The paper introduces a new direction in quality-of-service-aware networked sensing that designs communication protocols and scheduling policies for data delivery that are optimized specifically for decision needs. The work complements present decision monitoring and support tools and falls in the larger framework of decision-driven resource managem...
Article
Full-text available
Quality of information (QoI) provides a context-dependent measure of the utility that a network delivers to its users by incorporating non-traditional information attributes. Quickly and easily predicting performance and limitations of a network using QoI metrics is a valuable tool for network design. Even more useful is an understanding of how net...
Article
In-vehicle context sensing can detect many aspects of driver behavior and the environment, such as drivers changing lanes, stop signs, road grade and potholes, and these features can be used to improve driver safety and comfort, and engine efficiency. In general, detecting these features can use either on-board sensors on the vehicle (car sensors),...
Conference Paper
Full-text available
Traffic estimation has been a long-studied problem, but prior work has mostly provided coarse estimates over large areas. This work proposes effective fine-grained traffic volume estimation using in-vehicle dashboard mounted cameras. Existing work on traffic estimation relies on static traffic cameras that are usually deployed at crowded intersecti...
Conference Paper
Full-text available
This paper explores the minimal dataset necessary at vehicular edge nodes, to effectively differentiate drivers using data from existing in-vehicle sensors. This facilitates novel personalization, insurance, advertising, and security applications but can also help in understanding the privacy sensitivity of such data. Existing work on differentiati...
Conference Paper
Full-text available
Like today's autonomous vehicle prototypes, vehicles in the future will have rich sensors to map and identify objects in the environment. For example, many autonomous vehicle prototypes today come with line-of-sight depth perception sensors like 3D cameras. These cameras are used for improving vehicular safety in autonomous driving, but have fundam...
Conference Paper
Context awareness is crucial for ubiquitous computing, and position is an important aspect of context. In an ideal world, every stationary object or entity in the built environment would be associated with position, so that applications can have precise spatial context about the environment surrounding a human. In this paper, we take a step towards...
Conference Paper
Large flows like videos consume significant bandwidth. Some ISPs actively manage these high volume flows with techniques like policing, which enforces a flow rate by dropping excess traffic. While the existence of policing is well known, our contribution is an Internet-wide study quantifying its prevalence and impact on video quality metrics. We de...
Conference Paper
As data centers grow larger and strive to provide tight performance and availability SLAs, their monitoring infrastructure must move from passive systems that provide aggregated inputs to human operators, to active systems that enable programmed control. In this paper, we propose Trumpet, an event monitoring system that leverages CPU resources and...
Conference Paper
Maintaining the highest levels of availability for content providers is challenging in the face of scale, network evolution and complexity. Little, however, is known about failures large content providers are susceptible to, and what mechanisms they employ to ensure high availability. From a detailed analysis of over 100 high-impact failure events...
Conference Paper
Developers deploying web applications in the cloud often need to determine how changes such as service tiers or runtime loads may affect user-perceived page load time. We devise and evaluate a systematic methodology for exploring such "what-if" questions at the time a web application is deployed. Given a website, a web request, and “whatif” scenari...
Article
As the volume of content served by content distribution networks (CDNs) grows, these networks evolve to improve performance. Their performance is difficult to characterize because it depends on a number of factors. In this paper, we develop a methodology called DBit that can determine whether one CDN’s user-perceived performance is statistically di...
Conference Paper
With the standardization of HTTP/2, content providerswant to understand the benefits and pitfalls of transitioning to the new standard. Using a large dataset of HTTP/1.1 resource timing data from production traffic on Akamai’s CDN, and a model of HTTP/2 behavior, we obtain the distribution of performance differences between the protocol versions fo...
Article
Full-text available
This paper complements the large body of social sensing literature by developing means for augmenting sensing data with inference results that "fill-in" missing pieces. It specifically explores the synergy between (i) inference techniques used for filling-in missing pieces and (ii) source selection techniques used to determine which pieces to retri...
Conference Paper
Software-defined networks can enable a variety of concurrent, dynamically instantiated, measurement tasks, that provide fine-grain visibility into network traffic. Recently, there have been many proposals for using sketches for network measurement. However, sketches in hardware switches use constrained resources such as SRAM memory, and the accurac...
Conference Paper
Precise positioning of an automobile to within lane-level precision can enable better navigation and context-awareness. However, GPS by itself cannot provide such precision in obstructed urban environments. In this paper, we present a system called CARLOC for lane-level positioning of automobiles. CARLOC uses three key ideas in concert to improve p...
Conference Paper
Precise positioning of an automobile to within lane-level precision can enable better navigation and context-awareness. However, GPS by itself cannot provide such precision in obstructed urban environments. In this paper, we present a system called CARLOC for lane-level positioning of automobiles. CARLOC uses three key ideas in concert to improve p...
Conference Paper
The Internet suffers from well-known performance, reliability, and security problems. However, proposed improvements have seen little adoption due to the difficulties of Internet-wide deployment. We observe that, instead of trying to solve these problems in the general case, it may be possible to make substantial progress by focusing on solutions t...
Conference Paper
To reduce page load times and bandwidth usage for mobile web browsing, middleboxes that compress page content are commonly used today. Unfortunately, this can hurt performance in many cases; via an extensive measurement study, we show that using middleboxes to facilitate compression results in up to 28% degradation in page load times when the clien...
Conference Paper
We develop data retrieval algorithms for crowd-sensing applications that reduce the underlying network bandwidth consumption or any additive cost metric by exploiting logical dependencies among data items, while maintaining the level of service to the client applications. Crowd sensing applications refer to those where local measurements are perfor...
Conference Paper
Full-text available
People increasingly use mobile devices as their primary means to access the Internet. While it is well known that cellular network operators employ middleboxes, the details of their behavior and their impact on Web performance are poorly understood. This paper presents an analysis of proxy behavior and how transparent Web proxies interact with HTTP...
Article
This paper considers Quality-of-Information (QoI) aware resource allocation policies for multiuser networks. QoI is a recently introduced composite metric which is impacted by a number of attributes of information communicated from the source(s) to the destination(s), and as such differs from traditional quality-of-service metrics considered to dat...
Conference Paper
Automotive apps can improve efficiency, safety, comfort, and longevity of vehicular use. These apps achieve their goals by continuously monitoring sensors in a vehicle, and combining them with information from cloud databases in order to detect events that are used to trigger actions (e.g., alerting a driver, turning on fog lights, screening calls)...
Article
In software-defined networking, the controller installs flow-based rules at switches either proactively or reactively. The reactive approach allows controller applications to make dynamic decisions about incoming traffic, but performs worse than the proactive one due to the controller involvement. To support dynamic applications with better perform...
Article
Software-defined networks can enable a variety of concurrent, dynamically instantiated, measurement tasks, that provide fine-grain visibility into network traffic. Recently, there have been many proposals to configure TCAM counters in hardware switches to monitor traffic. However, the TCAM memory at switches is fundamentally limited and the accurac...
Article
Software-defined networks can enable a variety of concurrent, dynamically instantiated, measurement tasks, that provide fine-grain visibility into network traffic. Recently, there have been many proposals to configure TCAM counters in hardware switches to monitor traffic. However, the TCAM memory at switches is fundamentally limited and the accurac...
Article
Mobile app ecosystems have experienced tremendous growth in the last six years. This has triggered research on dynamic analysis of performance, security, and correctness properties of the mobile apps in the ecosystem. Exploration of app execution using automated UI actions has emerged as an important tool for this research. However, existing resear...
Article
Location-Based Mobile Service (LBMS) is one of the most popular smartphone services. LBMS enables people to more easily connect with each other and analyze the aspects of their lives. However, sharing location data can leak people's privacy. We present PDVLoc, a controlled location data-sharing framework based on selectively sharing data through a...
Conference Paper
Full-text available
This paper describes the exploitation of hierarchical data names to achieve information-utility maximizing data collec-tion in social sensing applications. We describe a novel transport abstraction, called the information funnel. It encapsulates a data collection protocol for social sensing that maximizes a measure of delivered information utility,...
Conference Paper
This paper complements the large body of social sensing literature by developing means for augmenting sensing data with inference results that "fill-in" missing pieces. Unlike trend-extrapolation methods, we focus on prediction in disaster scenarios where disruptive trend changes occur. A set of prediction heuristics (and a standard trend extrapola...
Conference Paper
Full-text available
This poster describes the information funnel, a data collection protocol for social sensing that maximizes a measure of delivered information utility. We argue that information-centric networking (ICN), where data objects are named instead of hosts, is especially suited for utility-maximizing transport in resource-constrained environments, because...
Conference Paper
Full-text available
As mobile Internet becomes more popular, carriers and content providers must engineer their topologies, routing configurations, and server deployments to maintain good performance for users of mobile devices. Understanding the impact of Internet topology and routing on mobile users requires broad, longitudinal network measurements conducted from mo...
Article
Traditional routing metrics designed for wireless networks are application-agnostic. In this paper, we consider a wireless network where the application flows consist of video traffic. From a user perspective, reducing the level of video distortion is critical. We ask the question “Should the routing policies change if the end-to-end video distorti...
Article
This paper complements the large body of social sensing literature by developing means for augmenting sensing data with inference results that " fill-in " missing pieces. Unlike trend-extrapolation methods, we focus on prediction in disaster scenarios where disruptive trend changes occur. A set of prediction heuristics (and a standard trend extrapo...
Conference Paper
Video transfers using smartphones are becoming increasingly popular. To prevent the interception of content from eavesdroppers, video flows must be encrypted. However, encryption results in a cost in terms of processing delays and energy consumed on the user's device. We argue that encrypting only certain parts of the flow can create sufficiently h...
Conference Paper
Full-text available
Transient performance anomalies when accessing websites can be hard to replicate and make it difficult to detect and remedy their root causes. We propose a tool which passively monitors browser behavior and network traffic, while actively probing the network when detecting performance anomalies, and determining their root causes.
Article
To address the pressing need to provide transparency into the online targeted advertising ecosystem, we present AdReveal, a practical measurement and analysis framework, that provides a first look at the prevalence of different ad targeting mechanisms. We design and implement a browser based tool that provides detailed measurements of online displa...
Conference Paper
Full-text available
In this demo, a learning system, called Metis, is presented that extrapolates missing pieces in participatory sensing data. The work addresses the challenge of incomplete coverage in participatory sensing applications, where lack of complete control over participant mobility and sensing patterns may create coverage gaps in space and in time. Metis...
Conference Paper
This paper explores the design of in-network caching policies for non-independent spot reporting content. The problem is motivated by autonomous sensor devices, such as soldier mounted cameras, that collect and store correlated data from the physical world. Physical states exhibit correlations in space and in time that need to be considered in cach...
Conference Paper
Modern content-distribution networks both provide bulk content and act as "serving infrastructure" for web services in order to reduce user-perceived latency. Serving infrastructures such as Google's are now critical to the online economy, making it imperative to understand their size, geographic distribution, and growth strategies. To this end, we...
Conference Paper
Computing-as-a-service has been evolving steadily. Today, private clouds (e.g., Google's internal shared computing cluster) as well as public clouds (e.g., Amazon's web services (AWS), Microsoft's Azure) provide computing abstractions at various levels: bare virtual machines, specialized languages and runtimes (e.g., for massively-parallel data pro...
Conference Paper
To serve users quickly, Web service providers build infrastructure closer to clients and use multi-stage transport connections. Although these changes reduce client-perceived round-trip times, TCP's current mechanisms fundamentally limit latency improvements. We performed a measurement study of a large Web service provider and found that, while con...
Conference Paper
Previous work on network measurements have explored several primitives of increasing complexity for measurement tasks at individual nodes, ranging from counters to hashing to arbitrary code fragments. In an SDN network, these primitives may require significant bandwidth, memory and processing resources, and the resources dedicated to these can affe...