Showing papers by "Shivkumar Kalyanaraman published in 2014"

SocketWatch: An autonomous appliance monitoring system

Abstract: A significant amount of energy is wasted by electrical appliances when they operate inefficiently either due to anomalies and/or incorrect usage. To address this problem, we present SocketWatch - an autonomous appliance monitoring system. SocketWatch is positioned between a wall socket and an appliance. SocketWatch learns the behavioral model of the appliance by analyzing its active and reactive power consumption patterns. It detects appliance malfunctions by observing any marked deviations from these patterns. SocketWatch is inexpensive and is easy to use: it neither requires any enhancement to the appliances nor to the power sockets nor any communication infrastructure. Moreover, the decentralized approach avoids communication latency and costs, and preserves data privacy. Real world experiments with multiple appliances indicate that SocketWatch can be an effective and inexpensive solution for reducing electricity wastage.

Personalised Public Transportation: A New Mobility Model for Urban and Suburban Transportation

Abstract: This paper explores a new vision for urban and suburban transportation, termed Personalised Public Transportation, which builds upon recent trends in vehicle sharing, electric vehicles, mobile payments and cloud computing. The goal is to build on the best of the worlds of private and public transportation. Private transportation offers ownership, comfort and convenience, but is higher cost, and subject to externalities (traffic jams, pollution, etc.). Public transportation is efficient, cheaper and has lower energy/carbon footprint, but has a last-mile problem (access) and low spatio-temporal coverage in suburbia. The authors envisage a future model of leasing public transportation via a service similar to cell-phone services, where the user pays for convenience and sharing of a network. The authors describe the key design features inherent to this mobility model. The vehicular platform allows the entire fleet to be operated and managed via a cloud computing service in order to maximize convenience and minimize cost. An optimization formulation to quantify the benefits of Personalised Public Transportation shows that it is a promising approach for transforming future generations of transportation into sustainable ecosystems.

The Switch Reordering Contagion: Preventing a Few Late Packets from Ruining the Whole Party

Abstract: Packet reordering has now become one of the most significant bottlenecks in next-generation switch designs. A switch practically experiences a reordering delay contagion, such that a few late packets may affect a disproportionate number of other packets. This contagion can have two possible forms. First, since switch designers tend to keep the switch flow order, i.e., the order of packets arriving at the same switch input and departing from the same switch output, a packet may be delayed due to packets of other flows with little or no reason. Further, within a flow, if a single packet is delayed for a long time, then all the other packets of the same flow will have to wait for it and suffer as well. In this paper, we suggest solutions against this reordering contagion. We first suggest several hash-based counter schemes that prevent inter-flow blocking and reduce reordering delay. We further suggest schemes based on network coding to protect against rare events with high queueing delay within a flow. Last, we demonstrate using both analysis and simulations that the use of these solutions can indeed reduce the resequencing delay. For instance, resequencing delays are reduced by up to an order of magnitude using real-life traces and a real hashing function.

Detecting cellular connectivity issues in a wireless communication network

Abstract: Various embodiments manage service issues in a wireless communication network. In one embodiment, a plurality of call detail records associated with a wireless communication network is received. The plurality of call detail records is analyzed. At least one pattern from the plurality of call detail records is identified based on analyzing the plurality of call detail records. The at least one pattern indicates at least one service issue occurred during a set of calls associated with each of the plurality of call detail records. A location associated with the at least one service issue that has occurred is identified based on identifying the at least one pattern.

Injecting electricity into a grid from distributed generation

Abstract: Methods and arrangements for managing electricity generation in a distributed electricity generation system. A plurality of data inputs are received comprising: a sensed state of a power grid; a sensed state of local energy storage; and a sensed demand of a local electricity load. The data inputs are combined, and, based on the combined data inputs, there is determined a destination of electricity that is generated in the distributed electricity generation system. The at least one destination is selected from the group consisting of: a local electricity load, the power grid, and the local energy storage. Other variants and embodiments are broadly contemplated herein.

On the estimation of available bandwidth in broadband cellular networks

Abstract: Over-the-top estimation of available bandwidth (AB) in a network path has been well studied for wired networks. The AB of a path denotes its slack capacity, i.e., the bandwidth available for use in the path without impacting the existing traffic. This estimation problem has been receiving attention only recently in cellular networks, which are increasingly becoming one of the main modes of access for a large number of applications. In this paper, we discuss the challenges posed by the problem, and why existing techniques developed for wired networks cannot be applied. We show that, interestingly, it may not even be feasible to estimate AB using over-the-top approaches under certain conditions, even when the wireless channel and traffic conditions are non-varying. We then present a novel AB estimation technique for cellular networks, which typically use proportional fair scheduling at base stations. When the wireless channel and traffic conditions are non-varying, our technique can accurately determine AB when it exceeds the "fair share" due to a new flow. We also extend the basic technique for estimation under conditions that are time-varying. The proposed methods can as well be used when one or more bottleneck links in a network path are fair-scheduled using algorithms such as weighted-fair queueing. We evaluate our methods using simulations and over operational networks, and present the results. In simulations, our technique is capable of detecting AB close to 90% of the time under feasible conditions even with bursty traffic.

Distributed Phase Balancing

Abstract: Methods, systems, and computer program products for distributed phase balancing are provided herein. A method of use in connection with a distribution network having a phase imbalance includes determining one or more power consumption parameters associated with a given entity of the distribution network; determining one or more power supply parameters associated with the given entity of the distribution network; and computing, based on said one or more power consumption parameters and said one or more power supply parameters, at least one of (i) a level of power consumption increase and/or decrease and (ii) a level of power supply increase and/or decrease associated with one or more devices of the given entity to remedy the phase imbalance within the distribution network.

Dynamically Delayed Delivery of Content in a Network

Abstract: Methods, systems, and articles of manufacture for dynamically delayed delivery of content in a network are provided herein. A method includes receiving, from a user device coupled to a network, a request for a content from the network; estimating a measure of available bandwidth on the network for delivery of the requested content at each of multiple periods of time; generating multiple schedules for the delivery of the requested content, wherein each of the multiple schedules is based on (i) the measure of available bandwidth on the network at one of the multiple periods of time and (ii) a predefined set of scheduling rules associated with the user device and the network; and delivering the requested content to the user device according to a schedule selected from the multiple schedules.

Enabling Location-Based Services 2.0: Challenges and Opportunities

Abstract: The next-generation mobile devices include smart watches, wristbands, wearables (e.g., Google Glass), etc. In the future such devices will constitute a large fraction of the total devices available in the market [1]. Latest studies confirm that location-based services are the most requested feature by developers with a market share of 13B in 2013 and have expected exponential growth [2]. Future location-based applications/services will use the data generated by the new mobile devices for providing enhanced user experience. This paper presents a vision of such next-generation location-based services, which we call LBS 2.0. We present the challenges and opportunities that LBS 2.0 will pose for mobile data management.

Weak state versus strong state: an analysis of a probabilistic state mechanism for dynamic networks

Abstract: Network protocols coordinate their decision making using information about entities in remote locations. Such information is provided by state entries. To remain valid, the state information needs to be refreshed via control messages. When it refers to a dynamic entity, the state has to be refreshed at a high rate to prevent it from becoming stale. In capacity constrained networks, this may deteriorate the overall performance of the network. The concept of weak state has been proposed as a remedy to this problem in the context of routing in mobile ad-hoc networks. Weak state is characterized by probabilistic semantics and local refreshes as opposed to strong state that is interpreted as absolute truth. A measure of the probability that the state remains valid, i.e. confidence, accompanies the state. The confidence is decayed in time to adapt to dynamism and to capture the uncertainty in the state information. This way, weak state remains valid without explicit state refresh messages. We evaluate the consistency of weak state and strong state using two notions of distortion. Pure distortion measures the average difference between the actual value of the entity and the value that is provided by the remote state. Informed distortion captures both this difference and the effect of confidence value on state consistency. Using a mathematical analysis and simulations, we show that weak state reduces the distortion values when it provides information about highly dynamic entities and/or it is utilized for protocols that is required to incur a low amount of overhead.

Intelligent composable multi-function battery pack

Abstract: A method of operating a battery pack includes identifying a plurality of batteries in the battery pack, estimating a state of charge of each of the plurality of the batteries, obtaining a plurality of parameters of each of the plurality of the batteries, and determining, selectively, a charge current or a discharge current for each of the plurality of batteries using the state of charge and the plurality of parameters of each of the plurality of the batteries.