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Articles 1 - 30 of 319

Full-Text Articles in Computer Engineering

Fly-By-Logic: A Tool For Unmanned Aircraft System Fleet Planning Using Temporal Logic, Yash Vardhan Pant, Rhudii A. Quaye, Houssam Abbas, Akarsh Varre, Rahul Mangharam May 2019

Fly-By-Logic: A Tool For Unmanned Aircraft System Fleet Planning Using Temporal Logic, Yash Vardhan Pant, Rhudii A. Quaye, Houssam Abbas, Akarsh Varre, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

Safe planning for fleets of Unmaned Aircraft Systems (UAS) performing complex missions in urban environments has typically been a challenging problem. In the United States of America, the National Aeronautics and Space Administration (NASA) and the Federal Aviation Administration (FAA) have been studying the regulation of the airspace when multiple such fleets of autonomous UAS share the same airspace, outlined in the Concept of Operations document (ConOps). While the focus is on the infrastructure and management of the airspace, the Unmanned Aircraft System (UAS) Traffic Management (UTM) ConOps also outline a potential airspace reservation based system for operation where operators ...


Electroanatomic Mapping To Determine Scar Regions In Patients With Atrial Fibrillation, Jiyue He, Kuk Jin Jang, Katie Walsh, Jackson Liang, Sanjay Dixit, Rahul Mangharam Apr 2019

Electroanatomic Mapping To Determine Scar Regions In Patients With Atrial Fibrillation, Jiyue He, Kuk Jin Jang, Katie Walsh, Jackson Liang, Sanjay Dixit, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

Left atrial voltage maps are routinely acquired during electroanatomic mapping in patients undergoing catheter ablation for atrial fibrillation (AF). For patients, who have prior catheter ablation when they are in sinus rhythm (SR), the voltage map can be used to identify low voltage areas (LVAs) using a threshold of 0.2 - 0.45 mV. However, such a voltage threshold for maps acquired during AF has not been well established. A prerequisite for defining a voltage threshold is to maximize the topologically matched LVAs between the electroanatomic mapping acquired during AF and SR. This paper demonstrates a new technique to improve ...


Temporal Logic Robustness For General Signal Classes, Houssam Abbas, Yash Vardhan Pant, Rahul Mangharam Apr 2019

Temporal Logic Robustness For General Signal Classes, Houssam Abbas, Yash Vardhan Pant, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

In multi-agent systems, robots transmit their planned trajectories to each other or to a central controller, and each receiver plans its own actions by maximizing a measure of mission satisfaction. For missions expressed in temporal logic, the robustness function plays the role of satisfaction measure. Currently, a Piece-Wise Linear (PWL) or piece-wise constant reconstruction is used at the receiver. This allows an efficient robustness computation algorithm - a.k.a. monitoring - but is not adaptive to the signal class of interest, and does not leverage the compression properties of more general representations. When communication capacity is at a premium, this is ...


Technical Report: Anytime Computation And Control For Autonomous Systems, Yash Vardhan Pant, Houssam Abbas, Kartik Mohta, Rhudii A. Quaye, Truong X. Nghiem, Joseph Devietti, Rahul Mangharam Apr 2019

Technical Report: Anytime Computation And Control For Autonomous Systems, Yash Vardhan Pant, Houssam Abbas, Kartik Mohta, Rhudii A. Quaye, Truong X. Nghiem, Joseph Devietti, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

The correct and timely completion of the sensing and action loop is of utmost importance in safety critical autonomous systems. A crucial part of the performance of this feedback control loop are the computation time and accuracy of the estimator which produces state estimates used by the controller. These state estimators, especially those used for localization, often use computationally expensive perception algorithms like visual object tracking. With on-board computers on autonomous robots being computationally limited, the computation time of a perception-based estimation algorithm can at times be high enough to result in poor control performance. In this work, we develop ...


Holistic Resource Allocation For Multicore Real-Time Systems, Meng Xu, Linh T.X. Phan, Hyon-Young Choi, Yuhan Lin, Haoran Li, Chenyang Lu, Insup Lee Apr 2019

Holistic Resource Allocation For Multicore Real-Time Systems, Meng Xu, Linh T.X. Phan, Hyon-Young Choi, Yuhan Lin, Haoran Li, Chenyang Lu, Insup Lee

Departmental Papers (CIS)

This paper presents CaM, a holistic cache and memory bandwidth resource allocation strategy for multicore real-time systems. CaM is designed for partitioned scheduling, where tasks are mapped onto cores, and the shared cache and memory bandwidth resources are partitioned among cores to reduce resource interferences due to concurrent accesses. Based on our extension of LITMUSRT with Intel’s Cache Allocation Technology and MemGuard, we present an experimental evaluation of the relationship between the allocation of cache and memory bandwidth resources and a task’s WCET. Our resource allocation strategy exploits this relationship to map tasks onto cores, and to ...


Robustness Evaluation Of Computer-Aided Clinical Trials For Medical Devices, Kuk Jin Jang, Yash Vardhan Pant, Bo Zhang, James Weimer, Rahul Mangharam Mar 2019

Robustness Evaluation Of Computer-Aided Clinical Trials For Medical Devices, Kuk Jin Jang, Yash Vardhan Pant, Bo Zhang, James Weimer, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

Medical cyber-physical systems, such as the implantable cardioverter defibrillator (ICD), require evaluation of safety and efficacy in the context of a patient population in a clinical trial. Advances in computer modeling and simulation allow for generation of a simulated cohort or virtual cohort which mimics a patient population and can be used as a source of prior information. A major obstacle to acceptance of simulation results as a source of prior information is the lack of a framework for explicitly modeling sources of uncertainty in simulation results and quantifying the effect on trial outcomes.

In this work, we formulate the ...


The St. Chad Gospels: Diachronic Manuscript Registration And Visualization, Stephen Parsons, C. Seth Parker, W. Brent Seales Jan 2019

The St. Chad Gospels: Diachronic Manuscript Registration And Visualization, Stephen Parsons, C. Seth Parker, W. Brent Seales

Manuscript Studies

This paper presents a software framework for the registration and visualization of layered image sets. To demonstrate the utility of these tools, we apply them to the St. Chad Gospels manuscript, relying on images of each page of the document as it appeared over time. An automated pipeline is used to perform non-rigid registration on each series of images. To visualize the differences between copies of the same page, a registered image viewer is constructed that enables direct comparisons of registered images. The registration pipeline and viewer for the resulting aligned images are generalized for use with other data sets.


Reducing Pulse Oximetry False Alarms Without Missing Life-Threatening Events, Hung Nguyen, Sooyong Jang, Radoslav Ivanov, Christopher P. Bonafide, James Weimer, Insup Lee Sep 2018

Reducing Pulse Oximetry False Alarms Without Missing Life-Threatening Events, Hung Nguyen, Sooyong Jang, Radoslav Ivanov, Christopher P. Bonafide, James Weimer, Insup Lee

Departmental Papers (CIS)

Alarm fatigue has been increasingly recognized as one of the most significant problems in the hospital environment. One of the major causes is the excessive number of false physiologic monitor alarms. An underlying problem is the inefficient traditional threshold alarm system for physiologic parameters such as low blood oxygen saturation (SpO2). In this paper, we propose a robust classification procedure based on the AdaBoost algorithm with reject option that can identify and silence false SpO2 alarms, while ensuring zero misclassified clinically significant alarms. Alarms and vital signs related to SpO2 such as heart rate and pulse rate ...


Computer Aided Clinical Trials For Implantable Cardiac Devices, Kuk Jin Jang, James Weimer, Houssam Abbas, Zhihao Jiang, Jackson Liang, Sanjay Dixit, Rahul Mangharam Jul 2018

Computer Aided Clinical Trials For Implantable Cardiac Devices, Kuk Jin Jang, James Weimer, Houssam Abbas, Zhihao Jiang, Jackson Liang, Sanjay Dixit, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

In this paper we aim to answer the question, ``How can modeling and simulation of physiological systems be used to evaluate life-critical implantable medical devices?'' Clinical trials for medical devices are becoming increasingly inefficient as they take several years to conduct, at very high cost and suffer from high rates of failure. For example, the Rhythm ID Goes Head-to-head Trial (RIGHT) sought to evaluate the performance of two arrhythmia discriminator algorithms for implantable cardioverter defibrillators, Vitality 2 vs. Medtronic, in terms of time-to-first inappropriate therapy, but concluded with results contrary to the initial hypothesis - after 5 years, 2,000+ patients ...


Bandwidth Optimal Data/Service Delivery For Connected Vehicles Via Edges, Deepak Gangadharan, Oleg Sokolsky, Insup Lee, Baekgyu Kim, Chung-Wei Lin, Shinichi Shiraishi Jul 2018

Bandwidth Optimal Data/Service Delivery For Connected Vehicles Via Edges, Deepak Gangadharan, Oleg Sokolsky, Insup Lee, Baekgyu Kim, Chung-Wei Lin, Shinichi Shiraishi

Departmental Papers (CIS)

The paradigm of connected vehicles is fast gaining lot of attraction in the automotive industry. Recently, a lot of technological innovation has been pushed through to realize this paradigm using vehicle to cloud (V2C), infrastructure (V2I) and vehicle (V2V) communications. This has also opened the doors for efficient delivery of data/service to the vehicles via edge devices that are closer to the vehicles. In this work, we propose an optimization framework that can be used to deliver data/service to the connected vehicles such that a bandwidth cost objective is optimized. For the first time, we also integrate a ...


A Novel Programming Language To Reduce Energy Consumption By Arrhythmia Monitoring Algorithms In Implantable Cardioverter-Defibrillators, Houssam Abbas, Konstantinos Mamouras, Alena Rodionova, Alur Rajeev, Jackson Liang, Sanjay Dixit, Rahul Mangharam May 2018

A Novel Programming Language To Reduce Energy Consumption By Arrhythmia Monitoring Algorithms In Implantable Cardioverter-Defibrillators, Houssam Abbas, Konstantinos Mamouras, Alena Rodionova, Alur Rajeev, Jackson Liang, Sanjay Dixit, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

No abstract provided.


Towards Overhead-Free Interface Theory For Compositional Hierarchical Real-Time Systems, Jin Hyun Kim, Kygong Hoon Kim, Arvind Easwaran, Insup Lee May 2018

Towards Overhead-Free Interface Theory For Compositional Hierarchical Real-Time Systems, Jin Hyun Kim, Kygong Hoon Kim, Arvind Easwaran, Insup Lee

Technical Reports (CIS)

Much recent research has been conducted on compositional real-time scheduling framework as the framework becomes a useful fundamental theory for real-time OS-Hypervisor. Much recent research has been conducted on compositional real-time scheduling as the framework becomes a useful fundamental theory for real-time OS-Hypervisor. However, compositional frameworks suffer from abstraction overheads in composing components. In this paper, we classify the composition overheads into i) supply abstraction overhead associated with the supply from a resource provider, and ii) demand abstraction overhead associated with the component workload. Then, we provide sufficient conditions for each abstraction overhead to be eliminated. In addition, this paper ...


Data Freshness Over-Engineering: Formulation And Results, Dagaen Golomb, Deepak Gangadharan, Sanjian Chen, Oleg Sokolsky, Insup Lee May 2018

Data Freshness Over-Engineering: Formulation And Results, Dagaen Golomb, Deepak Gangadharan, Sanjian Chen, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

In many application scenarios, data consumed by real-time tasks are required to meet a maximum age, or freshness, guarantee. In this paper, we consider the end-to-end freshness constraint of data that is passed along a chain of tasks in a uniprocessor setting. We do so with few assumptions regarding the scheduling algorithm used. We present a method for selecting the periods of tasks in chains of length two and three such that the end-to-end freshness requirement is satisfied, and then extend our method to arbitrary chains. We perform evaluations of both methods using parameters from an embedded benchmark suite (E3S ...


Generic Formal Framework For Compositional Analysis Of Hierarchical Scheduling Systems, Jalil Boudjadar, Jin Hyun Kim, Linh Thi Xuan Phan, Insup Lee, Kim G. Larsen, Ulrik Nyman May 2018

Generic Formal Framework For Compositional Analysis Of Hierarchical Scheduling Systems, Jalil Boudjadar, Jin Hyun Kim, Linh Thi Xuan Phan, Insup Lee, Kim G. Larsen, Ulrik Nyman

Departmental Papers (CIS)

We present a compositional framework for the specification and analysis of hierarchical scheduling systems (HSS). Firstly we provide a generic formal model, which can be used to describe any type of scheduling system. The concept of Job automata is introduced in order to model job instantiation patterns. We model the interaction between different levels in the hierarchy through the use of state-based resource models. Our notion of resource model is general enough to capture multi-core architectures, preemptiveness and non-determinism.


A Novel Programming Language To Reduce Energy Consumption By Arrhythmia Monitoring Algorithms In Implantable Cardioverter-Defibrillators, Houssam Abbas, Konstantinos Mamouras, Alena Rodionova, Alur Rajeev, Jackson Liang, Sanjay Dixit, Rahul Mangharam May 2018

A Novel Programming Language To Reduce Energy Consumption By Arrhythmia Monitoring Algorithms In Implantable Cardioverter-Defibrillators, Houssam Abbas, Konstantinos Mamouras, Alena Rodionova, Alur Rajeev, Jackson Liang, Sanjay Dixit, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

No abstract provided.


Openice-Lite: Towards A Connectivity Platform For The Internet Of Medical Things, Radoslav Ivanov, Hung Nguyen, James Weimer, Oleg Sokolsky, Insup Lee May 2018

Openice-Lite: Towards A Connectivity Platform For The Internet Of Medical Things, Radoslav Ivanov, Hung Nguyen, James Weimer, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

The Internet of Medical Things (IoMT) is poised to revolutionize medicine. However, medical device communication, coordination, and interoperability present challenges for IoMT applications due to safety, security, and privacy concerns. These challenges can be addressed by developing an open platform for IoMT that can provide guarantees on safety, security and privacy. As a first step, we introduce OpenICE-lite, a middleware for medical device interoperability that also provides security guarantees and allows other IoMT applications to view/analyze the data in real time. We describe two applications that currently utilize OpenICE-lite, namely (i) a critical pulmonary shunt predictor for infants during ...


Joint Rate Control And Demand Balancing For Electric Vehicle Charging, Fanxin Kong, Xue Liu, Insup Lee Apr 2018

Joint Rate Control And Demand Balancing For Electric Vehicle Charging, Fanxin Kong, Xue Liu, Insup Lee

Departmental Papers (CIS)

Charging stations have become indispensable infrastructure to support the rapid proliferation of electric vehicles (EVs). The operational scheme of charging stations is crucial to satisfy the stability of the power grid and the quality of service (QoS) to EV users. Most existing schemes target either of the two major operations: charging rate control and demand balancing. This partial focus overlooks the coupling relation between the two operations and thus causes the degradation on the grid stability or customer QoS. A thoughtful scheme should manage both operations together. A big challenge to design such a scheme is the aggregated uncertainty caused ...


Parameter Invariant Monitoring For Signal Temporal Logic, Nima Roohi, Ramneet Kaur, James Weimer, Oleg Sokolsky, Insup Lee Apr 2018

Parameter Invariant Monitoring For Signal Temporal Logic, Nima Roohi, Ramneet Kaur, James Weimer, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

Signal Temporal Logic (STL) is a prominent specification formalism for real-time systems, and monitoring these specifications, specially when (for different reasons such as learning) behavior of systems can change over time, is quite important. There are three main challenges in this area: (1) full observation of system state is not possible due to noise or nuisance parameters, (2) the whole execution is not available during the monitoring, and (3) computational complexity of monitoring continuous time signals is very high. Although, each of these challenges has been addressed by different works, to the best of our knowledge, no one has addressed ...


Cyber-Physical System Checkpointing And Recovery, Fanxin Kong, Meng Xu, James Weimer, Oleg Sokolsky, Insup Lee Apr 2018

Cyber-Physical System Checkpointing And Recovery, Fanxin Kong, Meng Xu, James Weimer, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

Transitioning to more open architectures has been making Cyber-Physical Systems (CPS) vulnerable to malicious attacks that are beyond the conventional cyber attacks. This paper studies attack-resilience enhancement for a system under emerging attacks in the environment of the controller. An effective way to address this problem is to make system state estimation accurate enough for control regardless of the compromised components. This work follows this way and develops a procedure named CPS checkpointing and recovery, which leverages historical data to recover failed system states. Specially, we first propose a new concept of physical-state recovery. The essential operation is defined as ...


Logsafe: Secure And Scalable Data Logger For Iot Devices, Hung Nguyen, Radoslav Ivanov, Linh T.X. Phan, Oleg Sokolsky, James Weimer, Insup Lee Apr 2018

Logsafe: Secure And Scalable Data Logger For Iot Devices, Hung Nguyen, Radoslav Ivanov, Linh T.X. Phan, Oleg Sokolsky, James Weimer, Insup Lee

Departmental Papers (CIS)

As devices in the Internet of Things (IoT) increase in number and integrate with everyday lives, large amounts of personal information will be generated. With multiple discovered vulnerabilities in current IoT networks, a malicious attacker might be able to get access to and misuse this personal data. Thus, a logger that stores this information securely would make it possible to perform forensic analysis in case of such attacks that target valuable data. In this paper, we propose LogSafe, a scalable, fault-tolerant logger that leverages the use of Intel Software Guard Extensions (SGX) to store logs from IoT devices efficiently and ...


Context-Aware Detection In Medical Cyber-Physical Systems, Radoslav Ivanov, James Weimer, Insup Lee Apr 2018

Context-Aware Detection In Medical Cyber-Physical Systems, Radoslav Ivanov, James Weimer, Insup Lee

Departmental Papers (CIS)

This paper considers the problem of incorporating context in medical cyber-physical systems (MCPS) applications for the purpose of improving the performance of MCPS detectors. In particular, in many applications additional data could be used to conclude that actual measurements might be noisy or wrong (e.g., machine settings might indicate that the machine is improperly attached to the patient); we call such data context. The first contribution of this work is the formal definition of context, namely additional information whose presence is associated with a change in the measurement model (e.g., higher variance). Given this formulation, we developed the ...


Multi-Mode Virtualization For Soft Real-Time Systems, Haoran Li, Meng Xu, Chong Li, Chenyang Lu, Christopher Gill, Linh T.X. Phan, Insup Lee, Oleg Sokolsky Apr 2018

Multi-Mode Virtualization For Soft Real-Time Systems, Haoran Li, Meng Xu, Chong Li, Chenyang Lu, Christopher Gill, Linh T.X. Phan, Insup Lee, Oleg Sokolsky

Departmental Papers (CIS)

Real-time virtualization is an emerging technology for embedded systems integration and latency-sensitive cloud applications. Earlier real-time virtualization platforms require offline configuration of the scheduling parameters of virtual machines (VMs) based on their worst-case workloads, but this static approach results in pessimistic resource allocation when the workloads in the VMs change dynamically. Here, we present Multi-Mode-Xen (M2-Xen), a real-time virtualization platform for dynamic real-time systems where VMs can operate in modes with different CPU resource requirements at run-time. M2-Xen has three salient capabilities: (1) dynamic allocation of CPU resources among VMs in response to their mode changes, (2) overload avoidance at ...


Fly-By-Logic: Control Of Multi-Drone Fleets With Temporal Logic Objectives, Yash Vardhan Pant, Houssam Abbas, Rhudii A. Quaye, Rahul Mangharam Mar 2018

Fly-By-Logic: Control Of Multi-Drone Fleets With Temporal Logic Objectives, Yash Vardhan Pant, Houssam Abbas, Rhudii A. Quaye, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

The problem of safe planning and control for multi- drone systems across a variety of missions is of critical impor- tance, as the scope of tasks assigned to such systems increases. In this paper, we present an approach to solve this problem for multi-quadrotor missions. Given a mission expressed in Signal Temporal Logic (STL), our controller maximizes robustness to generate trajectories for the quadrotors that satisfy the STL spec- ification in continuous-time. We also show that the constraints on our optimization guarantees that these trajectories can be tracked nearly perfectly by lower level off-the-shelf position and attitude controllers. Our approach ...


Generalized Robust Mtl Semantics For Problems In Cardiac Electrophysiology, Houssam Abbas, Rahul Mangharam Mar 2018

Generalized Robust Mtl Semantics For Problems In Cardiac Electrophysiology, Houssam Abbas, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

Robustness-Guided Falsification (RGF) is an efficient

testing technique that tries to find a system execution that

violates some formal specification, by minimizing the robustness

of the specification over the set of initial conditions of the

system. Robustness uses an underlying distance function on

the space of system executions. As RGF is applied to new fields

like medicine, it is essential to determine whether our distances

still capture the domain expert’s intuition of which executions

are similar and which are not. Motivated by the problem of

testing the algorithms of cardiac defibrillators implanted in

millions of patients worldwide, this work ...


Learning And Control Using Gaussian Processes, Achin Jain, Truong X Nghiem, Manfred Morari, Rahul Mangharam Feb 2018

Learning And Control Using Gaussian Processes, Achin Jain, Truong X Nghiem, Manfred Morari, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

Building physics-based models of complex physical systems like buildings and chemical plants is extremely cost and time prohibitive for applications such as real-time optimal control, production planning and supply chain logistics. Machine learning algorithms can reduce this cost and time complexity, and are, consequently, more scalable for large-scale physical systems. However, there are many practical challenges that must be addressed before employing machine learning for closed-loop control. This paper proposes the use of Gaussian Processes (GP) for learning control-oriented models: (1) We develop methods for the optimal experiment design (OED) of functional tests to learn models of a physical system ...


Parameter-Invariant Monitor Design For Cyber Physical Systems, James Weimer, Radoslav Ivanov, Sanjian Chen, Alexander Roederer, Oleg Sokolsky, Insup Lee Jan 2018

Parameter-Invariant Monitor Design For Cyber Physical Systems, James Weimer, Radoslav Ivanov, Sanjian Chen, Alexander Roederer, Oleg Sokolsky, Insup Lee

Departmental Papers (CIS)

The tight interaction between information technology and the physical world inherent in Cyber-Physical Systems (CPS) can challenge traditional approaches for monitoring safety and security. Data collected for robust CPS monitoring is often sparse and may lack rich training data describing critical events/attacks. Moreover, CPS often operate in diverse environments that can have significant inter/intra-system variability. Furthermore, CPS monitors that are not robust to data sparsity and inter/intra-system variability may result in inconsistent performance and may not be trusted for monitoring safety and security. Towards overcoming these challenges, this paper presents recent work on the design of parameter-invariant ...


Instrumentation, Data, And Algorithms For Visually Understanding Haptic Surface Properties, Alexander Burka Jan 2018

Instrumentation, Data, And Algorithms For Visually Understanding Haptic Surface Properties, Alexander Burka

Publicly Accessible Penn Dissertations

Autonomous robots need to efficiently walk over varied surfaces and grasp diverse objects. We hypothesize that the association between how such surfaces look and how they physically feel during contact can be learned from a database of matched haptic and visual data recorded from various end-effectors' interactions with hundreds of real-world surfaces. Testing this hypothesis required the creation of a new multimodal sensing apparatus, the collection of a large multimodal dataset, and development of a machine-learning pipeline.

This thesis begins by describing the design and construction of the Portable Robotic Optical/Tactile ObservatioN PACKage (PROTONPACK, or Proton for short), an ...


Autonomous Behaviors With A Legged Robot, Berkay Deniz Ilhan Jan 2018

Autonomous Behaviors With A Legged Robot, Berkay Deniz Ilhan

Publicly Accessible Penn Dissertations

Over the last ten years, technological advancements in sensory, motor, and computational capabilities have made it a real possibility for a legged robotic platform to traverse a diverse set of terrains and execute a variety of tasks on its own, with little to no outside intervention. However, there are still several technical challenges to be addressed in order to reach complete autonomy, where such a platform operates as an independent entity that communicates and cooperates with other intelligent systems, including humans. A central limitation for reaching this ultimate goal is modeling the world in which the robot is operating, the ...


Resilient Submodular Maximization For Control And Sensing, Vasileios Tzoumas Jan 2018

Resilient Submodular Maximization For Control And Sensing, Vasileios Tzoumas

Publicly Accessible Penn Dissertations

Fundamental applications in control, sensing, and robotics, motivate the design of systems by selecting system elements, such as actuators or sensors, subject to constraints that require the elements not only to be a few in number, but also, to satisfy heterogeneity or interdependency constraints (called matroid constraints). For example, consider the scenarios:

- (Control) Actuator placement: In a power grid, how should we place a few generators both to guarantee its stabilization with minimal control effort, and to satisfy interdependency constraints where the power grid must be controllable from the generators?

- (Sensing) Sensor placement: In medical brain-wearable devices, how should we ...


Strong Memory Consistency For Parallel Programming, Christian Delozier Jan 2018

Strong Memory Consistency For Parallel Programming, Christian Delozier

Publicly Accessible Penn Dissertations

Correctly synchronizing multithreaded programs is challenging, and errors can lead to program failures (e.g., atomicity violations). Existing memory consistency models rule out some possible failures, but are limited by depending on subtle programmer-defined locking code and by providing unintuitive semantics for incorrectly synchronized code. Stronger memory consistency models assist programmers by providing them with easier-to-understand semantics with regard to memory access interleavings in parallel code. This dissertation proposes a new strong memory consistency model based on ordering-free regions (OFRs), which are spans of dynamic instructions between consecutive ordering constructs (e.g. barriers). Atomicity over ordering-free

regions provides stronger atomicity ...