Showing papers by "Shivkumar Kalyanaraman published in 2012"

Vehicular Traffic Density State Estimation Based on Cumulative Road Acoustics

Abstract: This paper considers the problem of vehicular traffic density estimation, utilizing the information cues present in the cumulative acoustic signal acquired from a roadside-installed single microphone. This cumulative signal comprises several noise signals such as tire noise, engine noise, engine-idling noise, occasional honks, and air turbulence noise of multiple vehicles. The occurrence and mixture weightings of these noise signals are determined by the prevalent traffic density conditions on the road segment. For instance, under a free-flowing traffic condition, the vehicles typically move with medium to high speeds and thereby produce mainly tire noise and air turbulence noise and less engine-idling noise and honks. For slow-moving congested traffic, the cumulative signal will largely be dominated by engine-idling noise and honks; air turbulence and tire noises will be inconspicuous. Furthermore, these various noise signals have spectral content that are very different from each other and, hence, can be used to discriminate between the different traffic density states that lead to them. Therefore, in this work, we extract the short-term spectral envelope features of the cumulative acoustic signals and model their class-conditional probability distributions, conditioned on one of the three broad traffic density states, i.e., Jammed (0-10 km/h), Medium-Flow (10-40 km/h), and Free-Flow (40 km/h and above) traffic. While these states are coarse measures of the average traffic speed, they nevertheless can provide useful traffic density information in the often-chaotic and nonlane-driven traffic conditions of the developing geographies, where other techniques (magnetic loop detectors) are inapplicable. Based on these learned distributions, we use a Bayes' classifier to classify the acoustic signal segments spanning a duration of 5-30 s, which results in a high classification accuracy of ~95%. Using a discriminative classifier such as a support vector machine (SVM) results in further classification accuracy gains over the Bayes' classifier.

CrossRoads: Seamless VM mobility across data centers through software defined networking

Abstract: Most enterprises today run their applications on virtual machines (VMs). VM mobility - both live and offline, can provide enormous flexibility and also bring down OPEX (Operational Expenditure) costs. However, both live and offline migration of VMs is still limited to within a local network because of the complexities associated with cross subnet live and offline migration. These complexities mainly arise from the hierarchical addressing used by various layer 3 routing protocols. For cross data center VM mobility, virtualization vendors require that the network configuration of the new data center where a VM migrates must be similar to that of the old data center. This severely restricts wide spread use of VM migration across data center networks. For offline migration, the above limitations can be overcome by reconfiguring IP addresses for the migrated VMs. However, even this effort is non-trivial and time consuming as these IP addresses are embedded in various configuration files inside these VMs. As enterprises grow and new data centers emerge in different geographic locations, there is a need to interconnect these data centers in a way that allows seamless VM mobility. In this context, we present CrossRoads - a network fabric that provides layer agnostic and seamless live and offline VM mobility across multiple data centers. We leverage software defined networking and implement an OpenFlow based prototype of CrossRoads. CrossRoads extends the idea of location independence based on pseudo addresses proposed in recent research to work with a control plane overlay of OpenFlow network controllers in various data centers. We evaluate CrossRoads on an innovative testbed that leverages nested virtualization to emulate two data centers. Our results confirm that CrossRoads has negligible performance overhead as compared to a Default layer 2 network - its average performance was no worse than 2.3% as compared to Default fabric across all experiments. In some experiments, it even outperformed the Default by up to 30%.

Enabling Co-Existence of Hosts or Virtual Machines with Identical Addresses

Abstract: A method for enabling co-existence of multiple machines with identical addresses within a single data center network. The method includes assigning a unique pseudo identifier to each machine in the network that can be used for routing a packet to a destination machine, replacing a sender media access control address on an address resolution protocol request with a pseudo identifier of the sender at an edge network switch, retrieving a private network identifier from a mapping table based on the sender pseudo identifier and returning a pseudo identifier for the destination address based on the private network identifier, and replacing the pseudo identifier of the destination address with an actual identifier at a destination edge network switch for routing the packet to the destination machine.

Interconnecting data centers for migration of virtual machines

Abstract: Methods and arrangements for facilitating virtual machine migration across data centers. A virtual machine is designated for migration from a first data center to a second data center, the virtual machine including a real identifier. A pseudo identifier is assigned to the virtual machine, and the pseudo identifier is mapped to the real identifier at a controller of the first data center. The real identifier is replaced in a data packet with the pseudo identifier for a routing task. Communication is maintained between the controller of the first data center and a controller of the second data center, and the controllers are synchronized to update a correct location of the virtual machine. The virtual machine is migrated from the first data center to the second data center.

nPlug: a smart plug for alleviating peak loads

Abstract: The Indian electricity sector, despite having the world's fifth largest installed capacity, suffers from a 12.9% peaking shortage. This shortage could be alleviated, if a large number of deferrable loads, particularly the high powered ones, could be moved from on-peak to off-peak times. However, conventional DSM strategies may not be suitable for India as the local conditions usually favor only inexpensive solutions with minimal dependence on the pre-existing infrastructure. In this work, we present nPlug, a smart plug that sits between the wall socket and deferrable loads such as water heaters, washing machines, and electric vehicles. nPlugs combine real-time sensing and analytics to infer peak periods as well as supply-demand imbalance and reschedule attached appliances in a decentralized manner to alleviate peaks whenever possible. They do not require any manual intervention by the end consumer nor any enhancements to the appliances or existing infrastructure. Some of nPlug's capabilities are demonstrated using experiments on a combination of synthetic and real data collected from plug-level energy monitors. Our results indicate that nPlug can be an effective and inexpensive technology to address the peaking shortage.

A transport protocol to exploit multipath diversity in wireless networks

Abstract: Wireless networks (including wireless mesh networks) provide opportunities for using multiple paths. Multihoming of hosts, possibly using different technologies and providers, also makes it attractive for end-to-end transport connections to exploit multiple paths. In this paper, we propose a multipath transport protocol, based on a carefully crafted set of enhancements to TCP, that effectively utilizes the available bandwidth and diversity provided by heterogeneous, lossy wireless paths. Our Multi-Path LOss-Tolerant (MPLOT) transport protocol can be used to obtain significant goodput gains in wireless networks, subject to bursty, correlated losses with average loss rates as high as 50%. MPLOT is built around the principle of separability of reliability and congestion control functions in an end-to-end transport protocol. Congestion control is performed separately on individual paths, and the reliability mechanism works over the aggregate set of paths available for an end-to-end session. MPLOT distinguishes between congestion and link losses through Explicit Congestion Notification (ECN), and uses Forward Error Correction (FEC) coding to recover from data losses. MPLOT uses a dynamic packet mapping based on the current path characteristics to choose a path for a packet. Use of erasure codes and block-level recovery ensures that in MPLOT the receiving transport entity can recover all data as long as a necessary number of packets in the block are received, irrespective of which packets are lost. We present a theoretical analysis of the different design choices of MPLOT and show that MPLOT chooses its policies and parameters such that a desirable tradeoff between goodput with data recovery delay is attained. We evaluate MPLOT, through simulations, under a variety of test scenarios and demonstrate that it effectively exploits path diversity in addition to efficiently aggregating path bandwidths while remaining fair to a conventional TCP flow on each path.

On managing quality of experience of multiple video streams in wireless networks

Abstract: Managing the Quality-of-Experience (QoE) of video streaming for wireless clients is becoming increasingly important due to the rapid growth of video traffic on wireless networks. The inherent variability of the wireless channel as well as the Variable Bit Rate (VBR) of the compressed video streams make QoE management a challenging problem. Prior work has studied this problem in the context of transmitting a single video stream. In this paper, we investigate multiplexing schemes to transmit multiple video streams from a base station to mobile clients that use number of playout stalls as a performance metric. In this context, we present an epoch-by-epoch framework to fairly allocate wireless transmission slots to streaming videos. In each epoch our scheme essentially reduces the vulnerability to stalling by allocating slots to videos in a way that maximizes the minimum ‘playout lead’ across all videos. Next, we show that the problem of allocating slots fairly is NP-complete even for a constant number of videos. We then present a fast lead-aware greedy algorithm for the problem. Our choice of greedy algorithm is motivated by the fact that this algorithm is optimal when the channel quality of a user remains unchanged within an epoch (but different users may experience different channel quality). Moreover, our experimental results based on public MPEG-4 video traces and wireless channel traces that we collected from a WiMAX test-bed show that the lead-aware greedy approach performs a fair distribution of stalls across the clients when compared to other algorithms, while still maintaining similar or lower average number of stalls per client.

Providing Replication and Fail-Over as a Network Service in Data Centers

Abstract: Techniques for providing session level replication and fail-over as a network service include generating a replication rule that replicates network traffic destined for a primary server from an originating server to a network controller and installing said rule in a switch component, identifying flows from the originating server to the primary server, replicating each incoming data packet intended for the primary server to the network controller for replication and forwarding to replica servers, determining said primary server to be in a failed state based on a number of retransmissions of a packet, to selecting one of the replica servers as a fail-over target, and performing a connection level fail-over by installing a redirection flow in the switch component that redirects all packets destined to the primary server to the network controller, which forwards the packets to the replica server and forwards each response from the replica server to said originating server.

Determining a connectivity model in smart grids

Abstract: Methods and arrangements for determining a network connectivity model. Meters are interfaced with, and periodic synchronous power-related measurements are collected from different meters. Measurement messages are sent to a predetermined location for being consolidated and processed, and a network connectivity model is thereupon determined.

InSite: QoE-aware video delivery from cloud data centers

Abstract: The Internet is witnessing a rapid increase in video traffic. Due to the scalability and the cost-savings offered by cloud-computing, Internet video service providers are increasingly delivering their content from multi-tenant cloud data centers. One of the major challenges faced by such a video service provider is the management of the Quality-of-Experience (QoE) of the end-users in the presence of Variable Bit Rate (VBR) video flows, time varying network conditions in the Internet, and the bounded egress bandwidth provided by the data center. To this end, we present InSite, a light-weight and easy-to-deploy solution for managing the QoE of a set of video flows of a service provider, which are served from a data center. InSite is deployed at the egress of a data center, between the video servers and the clients, and manages the video flows that are transmitted over TCP. The solution uses a novel generalized binary search technique to concurrently search for the appropriate flow rates for a set of flows, with the goal of maximizing the QoE-fairness across the flows, as opposed to TCPfairness. The search takes into account the total egress bandwidth allocated for the set of video flows at the data center, the unknown and possibly time-varying capacities of any remote bottleneck links, and the playout buffer sizes of the video flows. The solution is also designed to operate with minimal modifications to the video servers and the clients. In our evaluations using extensive ns-3 simulations and a testbed implementation for serving videos over TCP, we observe that deploying InSite achieves several folds reduction in playout stalls over a system without InSite.

Dynamic service class upgrades in data networks

Abstract: A method, program product and system for dynamically offering upgraded services in a network. The method comprising the steps of: selecting users for a possible offer of an upgrade to services within the network, based on user activity at user devices accessing the network; obtaining network context data information regarding the user activity and the network; sequentially ordering the selected users based on a likelihood that the users will purchase the upgrade to services; determining the upgrade to services to be offered based on a service prediction availability within the network; and offering the upgrade to services to the selected users for a specific time period.

Wind farm layout in consideration of three-dimensional wake

Abstract: Methods and arrangements for determining a layout and dimensions of a wind farm. A three-dimensional wake model for a wind farm is generated, and a positioning and dimensioning model for turbines of the wind farm is developed based on the three-dimensional wake model.

Comet: Decentralized Complex Event Detection in Mobile Delay Tolerant Networks

Abstract: Increased commodity use of mobile devices has the potential to enable mission-critical monitoring applications. However, these mobile-enabled monitoring applications have to often work in environments where a delay-tolerant network (DTN) is the only feasible communication paradigm. Detection of complex (composite) events is fundamental to monitoring applications. However, the existing plan-based CED techniques are mostly centralized, and hence are inherently unscalable for DTNs. In this paper, we create Comet â" a decentralized plan-based, efficient and scalable CED for DTNs. Comet shares the task of detecting complex events (CEs) among multiple nodes, with each node detecting a part of the CE by aggregating two or more primitive events or sub-CEs. Comet uses a unique h-function to construct cost and delay efficient CED trees. As finding an optimal CED plan requires exponential-time, Comet finds near-optimal detection plans for individual CEs through a novel multi-level push-pull conversion algorithm. Performance results show that Comet reduces cost by up to 89% compared to pushing all primitive events and over 60% compared to a two-level exhaustive search algorithm.

Identity: A data center network fabric to enable co-existence of identical addresses

Abstract: Seamless virtual machine (VM) mobility within and across data centers brings its own set of problems. One of these problems is enabling co-existence of identical or overlapping layer-2 and layer-3 addresses in a single data center network. The motivation for this problem comes from a number of compelling scenarios. These include the need to backup and restore or replicate multi-tier applications that comprise of multiple VMs from one data center to another or within the same data center. This requires significant network reconfiguration costs as IP addresses of replicated VMs may clash with other existing IP addresses in the data center or with other replicas of the same VMs. Similarly, when multiple data centers need to be consolidated through a single data center interconnect, their address ranges may overlap. Lastly, cloud providers need to ensure that various customers can backup and restore their VMs which can have potentially conflicting addresses with other customers' VMs without requiring time consuming network reconfiguration efforts. In this paper, we present Identity - a data center network fabric that enables co-existence of hosts or VMs with identical layer 2 and layer 3 addresses. We use pseudo addresses to uniquely identify each host or VM and employ address resolution and duplicate detection techniques to enable co-existence of hosts and VMs with identical addresses. We leverage the centralized programmable control plane offered by OpenFlow and present the design and implementation of our scheme in Mininet. We provide an experimental evaluation of our scheme and validate that its average latency and throughput performance is as good as a default setup.

On the partial caching of streaming video

Abstract: Video objects are much larger in size than traditional web objects and tend not to be viewed in entirety. Hence, caching them partially is a promising approach. Also, the projected growth in video traffic over wireless cellular networks calls for resource-efficient caching mechanisms in the wireless edge to lower traffic over the cellular backhaul and peering links and their associated costs. An evaluation of traditional partial caching solutions proposed in the literature shows that known solutions are not robust to video viewing patterns, increasing object pool size, changing object popularity, or limitation in the resources available for caching at the wireless network elements. In this paper, to overcome the limitations, we propose a novel approach that adopts a flexible segmentation policy and generalizes both LRU and LFU when applied to segmented accesses, and in our simulations, is shown to significantly lower wireless backhaul traffic (by around 20--30% and in some cases even higher).

Plug arrangements for alleviating peak loads

Abstract: Methods and arrangements for load-shifting time deferrable devices. An electrical load scheduling mechanism is provided, and this is placed in communication with an appliance. Electrical grid load conditions are assessed, and delivery of electrical power to the appliance is scheduled via the electrical load scheduling mechanism. The scheduling includes altering a predetermined delivery of electric power to the appliance based on the assessed electrical grid conditions

On Exploiting degrees-of-freedom in whitespaces

Abstract: TV Whitespaces, recently opened up by the FCC for unlicensed use by wireless devices, are seen as a potential cellular offload solution, especially in dense metros. However, under the new database-driven guidelines, there are typically very few whitespace bands available in such dense metros to a high-powered fixed device, which plays the role of a cellular base station in whitespaces. To address the lack of degrees-of-freedom (DoF) with this traditional architecture of one high-powered serving device, we propose a novel base station design that co-locates and networks together many low-powered devices to act as a multiple-antenna array. Lower-powered whitespace devices have access to more spectral DoF, a property that is unique to whitespaces. In the first part of the paper, we solve an array design problem where we estimate the size of the array required to meet long-term (worst-case) throughput targets. Using extensive simulations, we show that by effectively exploiting both spatial and spectral DoF, the array design outperforms the traditional design in most network conditions. Specifically, the proposed design can support throughputs of the order of a WiMAX cell running applications such as high-definition television. In the second part of the paper, we turn our attention to the operational aspects of such a design. Recognizing that the proposed array can potentially contain hundreds of elements, we propose a dynamic ON-OFF power control algorithm that operates in conjunction with the MaxWeight data scheduling algorithm and responds to the current network state - queues and channels - of the system, thus making the system power-efficient.

Online and distributed optimization framework for wireless analytics

Abstract: A method, computer program product, and computer system directed to an online and distributed optimization framework for wireless analytics. A radio network controller determines a ranking for each of a plurality of received objects using a plurality of similarity graphs. The radio network controller extracts a common structure by collaborative filtering data associated with a plurality of user devices and the plurality of received objects. The common structure is analyzed to infer usage patterns within a time slot. The radio network controller stores a subset of the ranked objects of the plurality of received objects in response to the analysis.

Managed video services at edge-of-the-network

Abstract: Systems and methods for managing video delivery to mobile device clients. Videos are assimilated for transmission to clients, a playout lead is estimated for each video and the videos are transmitted to the clients.

Optimizing streaming of a group of videos

Abstract: Methods and arrangements for optimizing streaming of a group of videos. Throughput of video streams through a common link to at least two different destinations is permitted. An effective flow rate for each video stream is ascertained, and a playout lead for each video stream is estimated. The playout leads are equalized via dynamically changing the effective flow rates of the video streams.

Delayed data delivery options

Abstract: Systems and methods for effecting delayed delivery of data. There are received, at a scheduler, from a plurality of mobile computing devices, a plurality of requests for transmission of data objects. Responsive to the requests, communication is made to at least one of the devices at least one offer for a delayed transmission deadline of at least one data object. There is received, at the scheduler, at least one response to the at least one offer, and there is determined a scheduling priority of transmissions based on the at least one response.

Controlling communication between whitespace devices

Abstract: Methods, apparatuses, and computer program products for controlling communication between whitespace devices are provided. Embodiments include identifying, by a base-station array controller, a user whitespace device within a coverage area of a base-station array, wherein the base-station array includes a plurality of base-station whitespace devices of varying power consumption profiles; identifying for each base-station whitespace device, by the base-station array controller, transmission channels available to the base-station whitespace device; selecting from the plurality of base-station whitespace devices, by the base-station array controller, a base-station whitespace device based on the power consumption profiles and the identified available transmission channels corresponding to the plurality of base-station whitespace devices; and instructing, by the base-station array controller, the selected base-station whitespace device to communicate with the identified user whitespace device on one of the identified available transmission channels.

Zwischenspeichern von großen Objekten mit mehreren, unbekannten und variierenden Ankerpunkten an einer zwischengeschalteten Proxy-Einheit

Abstract: Verfahren, das Folgendes umfasst: Empfangen einer Anforderung von eigenstandigem Inhalt in einem Video-Objekt, wobei der Inhalt weder zwischengespeichert ist noch an einen zwischengespeicherten Video-Objektabschnitt angrenzt; Zwischenspeichern eines ersten Abschnitts des Video-Objekts; Zuweisen eines Werts zu dem ersten Video-Objektabschnitt; Empfangen einer anschliesenden Anforderung von Inhalt in dem Video-Objekt, wobei die anschliesende Anforderung dem Zugreifen auf den ersten Video-Objektabschnitt und einen zweiten, nicht zwischengespeicherten Abschnitt des Video-Objekts entspricht; Aktualisieren des Werts des ersten Video-Objektabschnitts; und Ermitteln einer Menge fur die Zwischenspeicherung und eines Werts fur den zweiten Video-Objektabschnitt, wobei das Empfangen einer anschliesenden Anforderung die Feststellung umfasst, ob der der Anforderung entsprechende Inhalt einen bereits zwischengespeicherten Video-Objektabschnitt uberlappt, und wobei die Feststellung Folgendes umfasst: Feststellen von der Anforderung entsprechendem Inhalt, der einen bereits zwischengespeicherten Video-Objektabschnitt teilweise uberlappt; und Aufteilen des bereits zwischengespeicherten Video-Objektabschnitts.

Ermöglichen des gleichzeitigen Vorhandenseins von Hostrechnern oder virtuellen Maschinen mit identischen Adressen

Abstract: Ein Verfahren, eine Vorrichtung und ein Herstellungsgegenstand, um das gleichzeitige Vorhandensein von mehreren Maschinen mit identischen Adressen in einem einzigen Netzwerk eines Rechenzentrums zu ermoglichen. Das Verfahren beinhaltet das Zuweisen einer eindeutigen Pseudokennung zu jeder Maschine in dem Netzwerk, welche zur Weiterleitung eines Pakets an eine Zielmaschine verwendet werden kann, das Ersetzen einer Medienzugriffssteuerungsadresse eines Senders in einer Anforderung eines Adressenauflosungsprotokolls durch eine Pseudokennung des Senders an einer Vermittlungsstelle am Rand eines Netzwerks, das Abrufen einer Kennung eines privaten Netzwerks aus einer Abgleichungstabelle auf der Grundlage der Pseudokennung des Senders und das Zurucksenden einer Pseudokennung fur die Zieladresse auf der Grundlage der Kennung des privaten Netzwerks und das Ersetzen der Pseudokennung der Zieladresse durch eine tatsachliche Kennung an einer Zielvermittlungsstelle am Rand eines Netzwerks, um das Paket an die Zielmaschine weiterzuleiten.

Caching large video objects with multiple, unknown and varying anchor points

Abstract: In a method for caching video object portions, a request for stand-­alone content in a video object (202, Figure 2) is received 502, the content neither being cached nor adjacent a cached video portion, and a first portion of the video object is cached 504. A value (e.g., relating to popularity, age, etc) is assigned 506 to the first video object portion. A subsequent request for content in the video object is received 508, the subsequent request corresponding to access to the first video object portion and a second, uncached portion (such as segment 212, Figure 2) of the video object. The value of the first video object portion is updated 510. Then, for the second video object portion, an amount to cache and a value are determined 512, e.g. based on video object value, available storage, or the size of the second portion. Thus, a method of partial caching of large video objects is provided, increasing the cumulative hit rate of edge caches and lowering traffic; only popular video segments may be cached, and already-cached video chunks may be split or divided (306e, 306f: Figure 3). The subsequent request may ascertain overlaps with cached data.

Enforcing fine-grained demand management in smart grids

Abstract: Methods and arrangements for enforcing demand management in electrical grids. Electrical power is provided from an electrical network to at least one substation, the electrical network including an electrical generation grid in communication with the at least one substation, the at least one substation comprising a power limiter. Electrical power is provided from the at least one substation to a plurality of locations, each location comprising a smart power demand manager which controls electrical power delivery to at least power-drawing item. There is detected, with respect to the electrical network, at least one discrepancy comprising at least one of: an unbalanced network load; an unscheduled network load; a change in network supply; and a change in network condition. In response to such detection, electrical power delivery is controlled via employing the power limiter of the at least one substation in collaboration with at least one smart power demand manager.

Online- und verteiltes optimierungsrahmenwerk für die mobilfunkanalyse

Abstract: Ein Verfahren, Computerprogrammprodukt und Computersystem, das auf ein Online- und verteiltes Optimierungsrahmenwerk fur die Mobilfunkanalyse gerichtet ist. Eine Funknetz-Steuereinheit ermittelt eine Rangfolge fur jedes aus einer Vielzahl von empfangenen Objekten unter Verwendung einer Vielzahl von Ahnlichkeitskurven. Die Funknetz-Steuereinheit extrahiert eine gemeinsame Struktur durch gemeinschaftliches Filtern von Daten, die einer Vielzahl von Benutzereinheiten und der Vielzahl von empfangenen Objekten zugehorig sind. Die gemeinsame Struktur wird analysiert, um Nutzungsmuster innerhalb eines Zeitfensters abzuleiten. Die Funknetz-Steuereinheit speichert eine Teilmenge der eingestuften Objekte aus der Vielzahl von empfangenen Objekten als Reaktion auf die Analyse.