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Articles 1 - 26 of 26
Full-Text Articles in Engineering
Real-Time Heart Model For Implantable Cardiac Device Validation And Verification, Zhihao Jiang, Miroslav Pajic, Allison T. Connolly, Sanjay Dixit, Rahul Mangharam
Real-Time Heart Model For Implantable Cardiac Device Validation And Verification, Zhihao Jiang, Miroslav Pajic, Allison T. Connolly, Sanjay Dixit, Rahul Mangharam
Rahul Mangharam
Designing bug-free medical device software is difficult, especially in complex implantable devices that may be used in unanticipated contexts. Safety recalls of pacemakers and implantable cardioverter defibrillators due to firmware problems between 1990 and 2000 affected over 200,000 devices, comprising 41% of the devices recalled and are increasing in frequency. There is currently no formal methodology or open experimental platform to validate and verify the correct operation of medical device software. To this effect, a real-time Virtual Heart Model (VHM) has been developed to model the electrophysiological operation of the functioning (i.e. during normal sinus rhythm) and malfunctioning (i.e. during …
Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam
Wispernet: Anti-Jamming For Wireless Sensor Networks, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …
Voice Over Sensor Networks, Rahul Mangharam, Anthony Rowe, Raj Rajkumar, Ryohei Suzuki
Voice Over Sensor Networks, Rahul Mangharam, Anthony Rowe, Raj Rajkumar, Ryohei Suzuki
Rahul Mangharam
Wireless sensor networks have traditionally focused on low duty-cycle applications where sensor data are reported periodically in the order of seconds or even longer. This is due to typically slow changes in physical variables, the need to keep node costs low and the goal of extending battery lifetime. However, there is a growing need to support real-time streaming of audio and/or low-rate video even in wireless sensor networks for use in emergency situations and shortterm intruder detection. In this paper, we describe a real-time voice stream-capability in wireless sensor networks and summarize our deployment experiences of voice streaming across a …
Meera: Cross-Layer Methodology For Energy Efficient Resource Allocation In Wireless Networks, Sofie Pollin, Rahul Mangharam, Bruno Bougard, Liesbet Van Der Perre, Ingrid Moerman, Ragunathan Rajkumar, Francky Catthoor
Meera: Cross-Layer Methodology For Energy Efficient Resource Allocation In Wireless Networks, Sofie Pollin, Rahul Mangharam, Bruno Bougard, Liesbet Van Der Perre, Ingrid Moerman, Ragunathan Rajkumar, Francky Catthoor
Rahul Mangharam
In many portable devices, wireless network interfaces consume upwards of 30% of scarce system energy. Reducing the transceiver’s power consumption to extend the system lifetime has therefore become a design goal. Our work is targated at this goal and is based on the following two observations. First, conventional energy management approaches have focused independently on minimizing the fixed energy cost (by shutdown) and on scalable energy costs (by leveraging, for example, the modulation, code-rate and transmission power). These two energy management approaches present a tradeoff. For example, lower modulation rates and transmission power minimize the variable energy component, but this …
Demo Abstract: Embedded Virtual Machines For Wiress Industrial Automation, Rahul Mangharam, Miroslav Pajic, Shivakumar Sastry
Demo Abstract: Embedded Virtual Machines For Wiress Industrial Automation, Rahul Mangharam, Miroslav Pajic, Shivakumar Sastry
Rahul Mangharam
The factory of the future is the Wireless Factory - fully programmable, nimble and adaptive to planned mode changes and unplanned faults. Today automotive assembly lines loose over $22,000 per minute of downtime. The systems are rigid, difficult to maintain, operate and diagnose. Our goal is to demonstrate the initial architecture and protocols for all-wireless factory control automation. Embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology …
Optimizing Transmission And Shutdown For Energy-Efficient Packet Scheduling In Sensor Networks, Sofie Pollin, Bruno Bougard, Rahul Mangharam, Liesbet Van Der Perre, Francky Catthoor, Ragunathan Rajkumar, Ingrid Moerman
Optimizing Transmission And Shutdown For Energy-Efficient Packet Scheduling In Sensor Networks, Sofie Pollin, Bruno Bougard, Rahul Mangharam, Liesbet Van Der Perre, Francky Catthoor, Ragunathan Rajkumar, Ingrid Moerman
Rahul Mangharam
Energy-efficiency is imperative to enable the deployment of sensor networks with satisfactory lifetime. Conventional power management in radio communication primarily focuses independently on the physical layer, medium access control (MAC) or routing and approaches differ depending on the levels of abstraction. At the physical layer, the fundamental trade-off that exists between transmission rate and energy is exploited. This leads to the lazy scheduling approach, which consists of transmitting with the lowest power over the longest feasible duration. At MAC level, power reduction techniques tend to keep the transmission as short as possible to maximize the radio's power-off interval. Those two …
Size Matters: Size-Based Scheduling For Mpeg-4 Over Wireless Channels, Rahul Mangharam, Mustafa Demirhan, Ragunathan Rajkumar, Dipankar Raychaudhuri
Size Matters: Size-Based Scheduling For Mpeg-4 Over Wireless Channels, Rahul Mangharam, Mustafa Demirhan, Ragunathan Rajkumar, Dipankar Raychaudhuri
Rahul Mangharam
For bursty traffic with a large peak-to-average ratio and a stochastic channel, is it possible to minimize the response time of every flow while maximizing the effective channel utilization and maintain fairness? This is the question we address in this paper. In wireless networks with a single shared channel, channel arbitration is a core issue for flows with throughput and timeliness requirements on the uplink and peer-to-peer links where the instantaneous demand is not known. This paper presents a link layer frame scheduling algorithm for delay-sensitive variable bit rate traffic, such as high-rate multimedia (MPEG-4), over a wireless channel. We …
Network Synthesis For Dynamical System Stabilization, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
Network Synthesis For Dynamical System Stabilization, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
Rahul Mangharam
We present our recent results in the area of distributed control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network acts as a decentralized structured controller. In this case, the network is not used only as a communication medium (as in traditional control paradigms), but instead as a fully distributed computational substrate. We show that the dynamics of the plant dictate the types of network topologies that can be used to stabilize the system. Finally, we describe how to obtain a stabilizing configuration for the WCN if the topological …
From Verification To Implementation: A Model Translation Tool And A Pacemaker Case Study, Miroslav Pajic, Zhihao Jiang, Insup Lee, Oleg Sokolsky, Rahul Mangharam
From Verification To Implementation: A Model Translation Tool And A Pacemaker Case Study, Miroslav Pajic, Zhihao Jiang, Insup Lee, Oleg Sokolsky, Rahul Mangharam
Rahul Mangharam
Model-Driven Design (MDD) of cyber-physical systems advocates for design procedures that start with formal modeling of the real-time system, followed by the model’s verification at an early stage. The verified model must then be translated to a more detailed model for simulation-based testing and finally translated into executable code in a physical implementation. As later stages build on the same core model, it is essential that models used earlier in the pipeline are valid approximations of the more detailed models developed downstream. The focus of this effort is on the design and development of a model translation tool, UPP2SF, and …
A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
Rahul Mangharam
We present a distributed scheme used for control over wireless networks. In our previous work, we introduced the concept of a Wireless Control Network (WCN), where the network itself, with no centralized node, acts as the controller. In this work, we show how the WCN can be modified to include observer style updates which substantially improves robustness of the closed-loop system to link failures. In addition, we analyze how the WCN simplifies extraction of the communication and computation schedules and enables system compositionality and scalability.
Spatio-Temporal Techniques For Anti-Jamming In Embedded Wireless Networks, Rahul Mangharam, Miroslav Pajic
Spatio-Temporal Techniques For Anti-Jamming In Embedded Wireless Networks, Rahul Mangharam, Miroslav Pajic
Rahul Mangharam
Electromagnetic jamming results in a loss of link reliability, increased energy consumption and packet delays. In the context of energy-constrained wireless networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This coordination results in statistical and predictable activity patterns that may be easily detected and jammed. To eliminate spatio-temporal patterns of communication in the link and network layers, we present WisperNet, an energy-efficient anti-jamming protocol.WisperNet employs hardware-based time synchronization and lightweight cryptographic hashing for coordinated temporal randomization of slot schedules at the link layer and adapts routes to avoid static jammers …
The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam
The Wireless Control Network: Synthesis And Robustness, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam
Rahul Mangharam
We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. Traditional networked control schemes are designed with one of the nodes in the network acting as a dedicated controller, while the other nodes simply route information to and from the controller and the plant. We introduce the concept of a Wireless Control Network (WCN) where the entire network itself acts as the controller. Specifically, at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire …
Optimal Fixed And Scalable Energy Management For Wireless Networks, Rahul Mangharam, Sofie Pollin, Bruno Bougard, Ragunathan Rajkumar, Francky Catthoor, Liesbet Van Der Perre, Ingrid Moerman
Optimal Fixed And Scalable Energy Management For Wireless Networks, Rahul Mangharam, Sofie Pollin, Bruno Bougard, Ragunathan Rajkumar, Francky Catthoor, Liesbet Van Der Perre, Ingrid Moerman
Rahul Mangharam
In many devices, wireless network interfaces consume upwards of 30% of scarce portable system energy. Extending the system lifetime by minimizing communication power consumption has therefore become a priority. Conventional energy management techniques focus independently on minimizing the fixed energy consumption of the transceiver circuit or on scalable transmission control. Fixed energy consumption is reduced by maximizing the transceiver shutdown interval. In contrast, variable transmission rate, coding and power can be leveraged to minimize energy costs. These two energy management approaches present a tradeoff in minimizing the overall system energy. For example, variable energy costs are minimized by transmitting at …
Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam
Anti-Jamming For Embedded Wireless Networks, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Resilience to electromagnetic jamming and its avoidance are difficult problems. It is often both hard to distinguish malicious jamming from congestion in the broadcast regime and a challenge to conceal the activity patterns of the legitimate communication protocol from the jammer. In the context of energy-constrained wireless sensor networks, nodes are scheduled to maximize the common sleep duration and coordinate communication to extend their battery life. This results in well-defined communication patterns with possibly predictable intervals of activity that are easily detected and jammed by a statistical jammer. We present an anti-jamming protocol for sensor networks which eliminates spatio-temporal patterns …
Autoplug: An Architecture For Remote Electronic Controller Unit Diagnostics In Automotive Systems, Yash Vardhan Pant, Miroslav Pajic, Rahul Mangharam
Autoplug: An Architecture For Remote Electronic Controller Unit Diagnostics In Automotive Systems, Yash Vardhan Pant, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
In 2010, over 20.3 million vehicles were recalled. Software issues related to automotive controls such as cruise control, anti-lock braking system, traction control and stability control, account for an increasingly large percentage of the overall vehicles recalled. There is a need for new and scalable methods to evaluate automotive controls in a realistic and open setting. We have developed AutoPlug, an automotive Electronic Controller Unit (ECU) architecture between the vehicle and a Remote Diagnostics Center to diagnose, test, update and verify controls software. Within the vehicle, we evaluate observerbased runtime diagnostic schemes and introduce a framework for remote management of …
Rt-Link: A Time-Synchronized Link Protocol For Energy-Constrained Multi-Hop Wireless Networks, Rahul Mangharam, Anthoney Rowe, Raj Rajkumar
Rt-Link: A Time-Synchronized Link Protocol For Energy-Constrained Multi-Hop Wireless Networks, Rahul Mangharam, Anthoney Rowe, Raj Rajkumar
Rahul Mangharam
We propose RT-Link, a time-synchronized link protocol for real-time wireless communication in industrial control, surveillance and inventory tracking. RT-Link provides predictable lifetime for battery-operated embedded nodes, bounded end-to-end delay across multiple hops, and collision-free operation. We investigate the use of hardwarebased time-synchronization for infrastructure nodes by using an AM carrier-current radio for indoors and atomic clock receivers for outdoors. Mobile nodes are synchronized via in-band software synchronization within the same framework. We identify three key observations in the design and deployment of RT-Link: (a) Hardware-based global-time synchronization is a robust and scalable option to in-band softwarebased techniques. (b) Achieving global …
A Framework For Validation Of Implantable Medical Devices, Miroslav Pajic, Zhihao Jiang, Allison Connolly, Rahul Mangharam
A Framework For Validation Of Implantable Medical Devices, Miroslav Pajic, Zhihao Jiang, Allison Connolly, Rahul Mangharam
Rahul Mangharam
Designing bug-free medical device software is difficult, especially in complex implantable devices used for rhythm management of the cardiac or the neurological system. There is currently no formal methodology or open experimental platform to validate the correct operation of implantable medical device software. We describe our recent work on heart modeling for the validation and verification of artificial cardiac pacemakers. As we extend this platform to more complex devices such as cardioverter-defibrillators, there are several significant challenges in the modeling of biological systems and their patient-specific response to external stimulus. Our goal over the longer term is to explore the …
Max: A Maximal Transmission Concurrency Mac For Wireless Networks With Regular Structure, Rahul Mangharam, Raj Rajkumar
Max: A Maximal Transmission Concurrency Mac For Wireless Networks With Regular Structure, Rahul Mangharam, Raj Rajkumar
Rahul Mangharam
Multi-hop wireless networks facilitate applications in metropolitan area broadband, home multimedia, surveillance and industrial control networks. Most applications require high end-to-end throughput and/or bounded delay. Current single-hop networks primarily employ random access link-layer protocols such as Carrier Sense Multiple Access (CSMA). These perform poorly in the multi-hop regime and provide no end-to-end QoS guarantees. The primary causes are uncoordinated interference and unfairness in exclusive access of the shared wireless medium. Furthermore, random access schemes do not leverage spatial reuse effectively and require routes to be link-aware. MAX is a time division multiplexed resource allocation framework for multi-hop networks with practical …
Embedded Virtual Machines For Robust Wireless Control Systems, Rahul Mangharam, Miroslav Pajic
Embedded Virtual Machines For Robust Wireless Control Systems, Rahul Mangharam, Miroslav Pajic
Rahul Mangharam
Embedded wireless networks have largely focused on open loop sensing and monitoring. To address actuation in closed loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the Embedded Virtual Machine (EVM), a …
Green Scheduling For Radiant Systems In Buildings, Truong Nghiem, Madhur Behl, George Pappas, Rahul Mangharam
Green Scheduling For Radiant Systems In Buildings, Truong Nghiem, Madhur Behl, George Pappas, Rahul Mangharam
Rahul Mangharam
In this report we look at the problem of peak power reduction for buildings with electric radiant floor heating systems. Uncoordinated operation of a multi-zone radiant floor heating system can result in temporally correlated electricity demand surges or peaks in the building’s electricity consumption. As peak power prices are 200-400 times that of the nominal rate, this uncoordinated activity can result in high electricity costs and expensive system operation. We have previously presented green scheduling as an approach for reducing the aggregate peak power consumption in buildings while ensuring that indoor thermal comfort is always maintained. This report extends the …
The Wireless Control Network: A New Approach For Control Over Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
The Wireless Control Network: A New Approach For Control Over Networks, Miroslav Pajic, Shreyas Sundaram, George Pappas, Rahul Mangharam
Rahul Mangharam
We present a method to stabilize a plant with a network of resource constrained wireless nodes. As opposed to traditional networked control schemes where the nodes simply route information to and from a dedicated controller (perhaps performing some encoding along the way), our approach treats the network itself as the controller. Specifically, we formulate a strategy for each node in the network to follow, where at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in its neighborhood. We show that this causes the entire network to behave as a …
The Wireless Control Network: Monitoring For Malicious Behavior, Shreyas Sundaram, Miroslav Pajic, Christoforos Hadjicostis, Rahul Mangharam, George Pappas
The Wireless Control Network: Monitoring For Malicious Behavior, Shreyas Sundaram, Miroslav Pajic, Christoforos Hadjicostis, Rahul Mangharam, George Pappas
Rahul Mangharam
We consider the problem of stabilizing a plant with a network of resource constrained wireless nodes. In a companion paper, we developed a protocol where each node repeatedly transmits a linear combination of the values in its neighborhood. For certain topologies, we showed that these linear combinations can be designed so that the closed loop system is stable (i.e., the wireless network itself acts as a controller for the plant). In this paper, we design a Intrusion Detection System (IDS) for this control scheme, which observes the transmissions of certain nodes in the network and uses that information to (a) …
Optimizing Transmission And Shutdown For Energy-Efficient Real-Time Packet Scheduling In Clustered Ad Hoc Networks, Sofie Pollin, Bruno Bougard, Rahul Mangharam, Francky Catthoor, Ingrid Moerman, Ragunathan Rajkumar, Liesbet Van Der Perre
Optimizing Transmission And Shutdown For Energy-Efficient Real-Time Packet Scheduling In Clustered Ad Hoc Networks, Sofie Pollin, Bruno Bougard, Rahul Mangharam, Francky Catthoor, Ingrid Moerman, Ragunathan Rajkumar, Liesbet Van Der Perre
Rahul Mangharam
Energy efficiency is imperative to enable the deployment of ad hoc networks. Conventional power management focuses independently on the physical orMAC layer and approaches differ depending on the abstraction level. At the physical layer, the fundamental tradeoff between transmission rate and energy is exploited, which leads to transmit as slow as possible. At MAC level, power reduction techniques aim to transmit as fast as possible to maximize the radios power-off interval. The two approaches seem conflicting and it is not obvious which one is the most appropriate.We propose a transmission strategy that optimally mixes both techniques in a multiuser context.We …
Closing The Loop: A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam
Closing The Loop: A Simple Distributed Method For Control Over Wireless Networks, Miroslav Pajic, Shreyas Sundaram, Jerome Le Ny, George J. Pappas, Rahul Mangharam
Rahul Mangharam
We present a distributed scheme used for control over a network of wireless nodes. As opposed to traditional networked control schemes where the nodes simply route information to and from a dedicated controller (perhaps performing some encoding along the way), our approach, Wireless Control Network (WCN), treats the network itself as the controller. In other words, the computation of the control law is done in a fully distributed way inside the network. We extend the basic WCN strategy, where at each time-step, each node updates its internal state to be a linear combination of the states of the nodes in …
Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam
Embedded Virtual Machines For Robust Wireless Control And Actuation, Miroslav Pajic, Rahul Mangharam
Rahul Mangharam
Embedded wireless networks have largely focused on open-loop sensing and monitoring. To address actuation in closed-loop wireless control systems there is a strong need to re-think the communication architectures and protocols for reliability, coordination and control. As the links, nodes and topology of wireless systems are inherently unreliable, such time-critical and safety-critical applications require programming abstractions and runtime systems where the tasks are assigned to the sensors, actuators and controllers as a single component rather than statically mapping a set of tasks to a specific physical node at design time. To this end, we introduce the Embedded Virtual Machine (EVM), …
Topological Conditions For Wireless Control Networks, Miroslav Pajic, Shreyas Sundaram, George J. Pappas, Rahul Mangharam
Topological Conditions For Wireless Control Networks, Miroslav Pajic, Shreyas Sundaram, George J. Pappas, Rahul Mangharam
Rahul Mangharam
We study the problem of stabilizing a linear system over a wireless control network. We propose a scheme where each wireless node maintains a scalar state, and periodically updates it as a linear combination of neighboring plant outputs and node states. We make connections to decentralized fixed modes and structured system theory to provide conditions on the network topology that allow the system to be stabilized. Our analysis provides the minimal number of feedback edges that have to be introduced to stabilize the system over a network, and shows that as long as the network connectivity is larger than the …