University of North Alabama

Displaying 1-40 of 51 results

  • White Papers // May 2014

    Recovering from Overload in Multicore Mixed-Criticality Systems

    The MC2 mixed-criticality framework has been previously proposed for mixing safety-critical Hard Real-Time (HRT) and mission-critical Soft Real-Time (SRT) software on the same multicore computer. This paper focuses on the execution of SRT software within this framework. When determining SRT guarantees, jobs are provisioned based on a Provisioned Worst-Case Execution...

    Provided By University of North Alabama

  • White Papers // Apr 2014

    Minimizing Response Times of Automotive Dataflows on Multicore

    Dataflow software architectures are prevalent in prototypes of advanced automotive systems, for both driver-assisted and autonomous driving. Safety constraints of these systems necessitate real-time performance guarantees. Automotive prototypes often ensure such constraints through over provisioning and dedicated hardware; however, a commercially viable system must utilize as few low-cost multicore processors...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Soft Real-Time Scheduling on Performance Asymmetric Multicore Platforms

    In this paper, the authors discuss an approach for supporting soft real-time periodic tasks in Linux on performance Asymmetric Multicore Platforms (AMPs). Such architectures consist of a large number of processing units on one or several chips, where each processing unit is capable of executing the same instruction set at...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Parallel Real-Time Task Scheduling on Multicore Platforms

    Multicore architectures, which include several processors on a single chip, are being widely touted as a solution to the \"Thermal roadblock\"” imposed by single-core designs. Several chip makers have released dual-core chips, and a few designs with more than two cores have been announced as well. The authors propose a...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Real-Time Scheduling on Multicore Platforms

    Multicore architectures, which have multiple processing units on a single chip, are widely viewed as a way to achieve higher processor performance, given that thermal and power problems impose limits on the performance of single-core designs. Accordingly, several chip manufacturers have already released, or will soon release, chips with dual...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    LITMUS RT: A Testbed for Empirically Comparing Real-Time Multiprocessor Schedulers

    The authors present a real-time, Linux-based test-bed called LITMUSRT, which they have developed for empirically evaluating multiprocessor real-time scheduling algorithms. They also present the results from such an evaluation, in which partitioned Earliest-Deadline-First (EDF) scheduling, preemptive and non-preemptive global EDF scheduling, and two variants of the global PD2 P-fair algorithm...

    Provided By University of North Alabama

  • White Papers // Sep 2013

    Multiprocessor Feasibility Analysis of Recurrent Task Systems with Specified Processor Affinities

    In many current multiprocessor real-time operating systems, programmers have the ability to set affinity masks that pin a process to a specified subset of the processors in the system. Given a real-time task system consisting of a collection of implicit-deadline sporadic tasks with an affinity mask specified for each task...

    Provided By University of North Alabama

  • White Papers // Jun 2013

    Towards An Understanding of Cloud Computing's Impact On Organizational IT Strategy

    Cloud computing has become a dominant IT trend during the past two years for its potential to remarkably change the technology and business landscape. Although a lot have been discussed, its impacts on organizational IT strategy have not yet been fully addressed. In order to learn how cloud computing is...

    Provided By University of North Alabama

  • White Papers // Mar 2013

    Just-In-Time Code Reuse: On the Effectiveness of Fine-Grained Address Space Layout Randomization

    Fine-grained Address Space Layout Randomization (ASLR) has recently been proposed as a method of efficiently mitigating runtime attacks. In this paper, the authors introduce the design and implementation of a framework based on a novel attack strategy, dubbed just-in-time code reuse that undermines the benefits of fine-grained ASLR. Specifically, they...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    Feather-Trace: A Light-Weight Event Tracing Toolkit

    The authors present a light-weight event tracing toolkit for real-time operating systems on the Intel x86 platform. Their approach is wait-free, multiprocessor-safe, and introduces very low overhead. Only a single unconditional jump instruction is required to distinguish between enabled and disabled events. As a case study, they traced the locking...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    Integrating Hard/Soft Real-Time Tasks and Best-Effort Jobs on Multiprocessors

    An important trend in computing is the ongoing move towards system- and chip-level parallelism. Because of heat and power issues, it has become increasingly difficult to improve processor performance by increasing clock speeds. Therefore, in order to continue performance improvements, major processor manufacturers, such as Intel, AMD, IBM, and Sun...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    A Peer-to-Peer Architecture to Enable Versatile Lookup System Design

    The resource lookup requirements in applications such as web caching, web content search, content distribution, resource sharing, network monitoring and management, and e-commerce have caught the attention of Peer-To-Peer (P2P) distributed systems researchers. Over the past few years, several decentralized P2P lookup system designs have been proposed for addressing these...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    A Flexible Real-Time Locking Protocol for Multiprocessors

    Real-time scheduling algorithms for multiprocessor systems have been the subject of considerable recent interest. For such an algorithm to be truly useful in practice, support for semaphore-based locking must be provided. However, for many global scheduling algorithms, no such mechanisms have been proposed. Furthermore, in the partitioned case, most prior...

    Provided By University of North Alabama

  • White Papers // Oct 2012

    Towards Improving Browser Extension Permission Management and User Awareness

    Browsers have become the de-facto platform for users and their online presence. They have also become a rich environment for 3rd party extensions that enrich the user browsing experience by extending upon the browser's functionalities. Protecting user privacy against malicious or vulnerable extensions is an important task performed by modern...

    Provided By University of North Alabama

  • White Papers // Sep 2012

    An O(m) Analysis Technique for Supporting Real-Time Self-Suspending Task Systems

    In many real-time and embedded systems, suspension delays may occur when tasks block to access shared resources or interact with external devices. Unfortunately, prior analysis methods for dealing with suspensions are quite pessimistic. In this paper, a novel technique is presented for analyzing soft real-time sporadic self-suspending task systems, for...

    Provided By University of North Alabama

  • White Papers // Jul 2012

    The OMLP Family of Optimal Multiprocessor Real-Time Locking Protocols

    This paper presents the first suspsension-based multiprocessor real-time locking protocols with asymptotically optimal blocking bounds (under certain analysis assumptions). These protocols can be applied under any global, clustered, or partitioned job-level fixed-priority scheduler and support mutual exclusion, reader-writer exclusion, and k-exclusion constraints. Notably, the reader-writer and k-exclusion protocols are the...

    Provided By University of North Alabama

  • White Papers // Jun 2012

    Semi-Supervised Policy Recommendation for Online Social Networks

    Fine grain policy settings in social network sites are becoming a very important requirement for managing user's privacy. Incorrect privacy policy settings can easily lead to leaks in private and personal information. At the same time, being too restrictive would reduce the benefits of online social networks. This is further...

    Provided By University of North Alabama

  • White Papers // Jun 2012

    Security and Usability Challenges of Moving-Object CAPTCHAs: Decoding Codewords in Motion

    The authors explore the robustness and usability of moving-image object recognition (video) captchas, designing and implementing automated attacks based on computer vision techniques. Their approach is suitable for broad classes of moving-image captchas involving rigid objects. They first present an attack that defeats instances of such a captcha (NuCaptcha) representing...

    Provided By University of North Alabama

  • White Papers // Jun 2012

    Anomaly Discovery and Resolution in MySQL Access Control Policies

    Managing hierarchical and ne grained DBMS policies for a large number of users is a challenging task and it increases the probability of introducing mis-configurations and anomalies. In this paper, the authors present a formal approach to discover anomalies in database policies using Binary Decision Diagrams (BDDs) which allow finer...

    Provided By University of North Alabama

  • White Papers // Apr 2012

    Supporting Soft Real-Time Parallel Applications on Multicore Processors

    The prevalence of multicore processors has resulted in the wider applicability of parallel programming models such as OpenMP and MapReduce. A common goal of running parallel applications implemented under such models is to guarantee bounded response times while maximizing system utilization. Unfortunately, little previous work has been done that can...

    Provided By University of North Alabama

  • White Papers // Sep 2011

    Impact of Cross Traffic Burstiness on the Packet-Scale Paradigm

    The packet-scale paradigm is a novel framework for achieving ultra-high speed congestion control. Due to its reliance on finely-controlled inter-packet gaps, the paradigm is expected to be sensitive to transient burstiness in traffic encountered on bottleneck links. This paper uses a first-principles approach to study the impact of cross traffic...

    Provided By University of North Alabama

  • White Papers // Sep 2011

    Soft Real-Time on Multiprocessors: Are Analysis-Based Schedulers ReallyWorth It?

    The evolution of multicore platforms has led to much recent work on multiprocessor scheduling techniques for soft real-time workloads. However, end users routinely run such workloads atop general-purpose operating systems with seemingly good results, albeit typically on over-provisioned systems. This raises the question: when, if ever, is the use of...

    Provided By University of North Alabama

  • White Papers // Sep 2011

    Soft Real-Time on Multiprocessors: Are Analysis-Based Schedulers Really Worth It?

    The evolution of multicore platforms has led to much recent work on multiprocessor scheduling techniques for soft real-time workloads. However, end users routinely run such workloads atop general-purpose operating systems with seemingly good results, albeit typically on over-provisioned systems. This raises the question: when, if ever, is the use of...

    Provided By University of North Alabama

  • White Papers // Aug 2011

    Response-Time Analysis for Mixed Criticality Systems

    Many safety-critical embedded systems are subject to certification requirements. However, only a subset of the functionality of the system may be safety-critical and hence subject to certification; the rest of the functionality is non safety critical and does not need to be certified, or is certified to a lower level....

    Provided By University of North Alabama

  • White Papers // Jul 2011

    ROAuth: Recommendation Based Open Authorization

    Many major online platforms such as Facebook, Google, and Twitter, provide an open Application Programming Interface which allows third party applications to access user resources. The Open Authorization protocol (OAuth) was introduced as a secure and efficient method for authorizing third party applications without releasing a user's access credentials. However,...

    Provided By University of North Alabama

  • White Papers // May 2011

    An Approach for Automatic Selection of Relevance Features in Intrusion Detection Systems

    In Intrusion Detection Systems the environment data in general depends on many computer network related characteristics called features. However not all of the network features contribute to the discriminating properties of different types of intrusion attacks. Hence the selection of relevance features becomes an important requirement for the accurate and...

    Provided By University of North Alabama

  • White Papers // Apr 2011

    Is Semi-Partitioned Scheduling Practical?

    Semi-partitioned schedulers are - in theory - a particularly promising category of multiprocessor real-time scheduling algorithms. Unfortunately, issues pertaining to their implementation have not been investigated in detail, so their practical viability remains unclear. In this paper, the practical merit of three EDF-based semi-partitioned algorithms is accessed via an experimental...

    Provided By University of North Alabama

  • White Papers // Jan 2011

    Partitioned Real-Time Scheduling on Heterogeneous Shared-Memory Multiprocessors

    The authors consider several real-time scheduling problems on heterogeneous multiprocessor platforms, in which the different processors share a common memory pool. These include scheduling a collection of implicit-deadline sporadic tasks with the objective of meeting all deadlines; and scheduling a collection of independent jobs with the objective of minimizing the...

    Provided By University of North Alabama

  • White Papers // Jan 2011

    On Measuring the Similarity of Network Hosts: Pitfalls, New Metrics, and Empirical Analyses

    As the scope and scale of network data grows, security practitioners and network operators are increasingly turning to automated data analysis methods to extract meaningful information. Underpinning these methods are distance metrics that represent the similarity between two values or objects. In this paper, the authors argue that many of...

    Provided By University of North Alabama

  • White Papers // Oct 2010

    Assessing Students' Structured Programming Skills With Java: The Blue, Berry, and Blueberry Assignment

    Java is an object-oriented programming language. From a software engineering perspective, object-oriented design and programming is used at the architectural design, and structured design and programming is used at the detailed design within methods. As such, structured programming skills are fundamental to more advanced object-oriented programming concepts. Structured programming uses...

    Provided By University of North Alabama

  • White Papers // Oct 2010

    A Simple Abstraction for Data Modeling

    The problems that scientists face in creating well designed databases intersect with the concerns of data curation. Entity-relationship modeling and its variants have been the basis of most relational data modeling for decades. However, these abstractions and the relational model itself are intricate and have proved not to be very...

    Provided By University of North Alabama

  • White Papers // Sep 2010

    Supporting Soft Real-Time DAG-Based Systems on Multiprocessors With No Utilization Loss

    In work on globally-scheduled real-time multiprocessor systems, analysis is lacking for supporting real-time applications developed using general processing graph models. In this paper, it is shown that bounded deadline tardiness can be ensured for such applications on a multiprocessor with no utilization loss. This result is general: it is applicable...

    Provided By University of North Alabama

  • White Papers // Sep 2010

    An Empirical Comparison of Global, Partitioned, and Clustered Multiprocessor EDF Schedulers

    As multicore platforms become ever larger, overhead-related factors play a greater role in determining which real-time scheduling algorithms are preferable. In this paper, such factors are investigated through an empirical comparison of global, partitioned, and clustered EDF scheduling algorithms on a 24-core Intel system. On this platform, global EDF proved...

    Provided By University of North Alabama

  • White Papers // Aug 2010

    Optimality Results for Multiprocessor Real-Time Locking

    When locking protocols are used in real-time systems, bounds on blocking times are required when ensuring timing constraints. While the term "Blocking" is well-understood in the context of uniprocessor real-time systems, the same is not true in the multiprocessor case. In this paper, two definitions of blocking are presented that...

    Provided By University of North Alabama

  • White Papers // May 2010

    Decomposing RTT-Unfairness in Transport Protocols

    In this paper, the authors consider RTT-unfairness in most existing end-to-end congestion-control protocols, in which transfers with smaller RTTs are allocated a higher share of the bottleneck bandwidth. They consider the congestion-control mechanisms used by TCP NewReno and identify three aspects that introduce an RTT-based bias in different ways. Past...

    Provided By University of North Alabama

  • White Papers // May 2010

    User Centric Policy Management in Online Social Networks

    Online social networking sites are experiencing tremendous user growth with hundreds of millions of active users. As a result, there is a tremendous amount of user profile data online, e.g., name, birth date, etc. Protecting this data is a challenge. The task of access policy composition is a tedious and...

    Provided By University of North Alabama

  • White Papers // Apr 2010

    The Parallel Supply Function Abstraction for a Virtual Multiprocessor

    A new abstraction - the Parallel Supply Function (PSF) - is proposed for representing the computing capabilities offered by virtual platforms implemented atop identical multiprocessors. It is shown that this abstraction is strictly more powerful than previously-proposed ones, from the perspective of more accurately representing the inherent parallelism of the...

    Provided By University of North Alabama

  • White Papers // Feb 2010

    Scientific Data Repositories on the Web: An Initial Survey

    Science Data Repositories (SDRs) have been recognized as both critical to science, and undergoing a fundamental change. A websample study was conducted of 100 SDRs. Information on the websites and from administrators of the SDRs was reviewed to determine salient characteristics of the SDRs, which were used to classify SDRs...

    Provided By University of North Alabama

  • White Papers // Feb 2010

    Virtual Multiprocessor Platforms: Specification and Use

    The Parallel Supply Function (PSF) is proposed for representing the computing capabilities offered by virtual platforms implemented atop identical multiprocessors. It is shown that this abstraction is strictly more powerful than previously-proposed ones, from the perspective of more accurately representing the inherent parallelism of the provided computing capabilities. Sufficient tests...

    Provided By University of North Alabama

  • White Papers // Jan 2010

    Scheduling Suspendable, Pipelined Tasks With Non-Preemptive Sections in Soft Real-Time Multiprocessor Systems

    While most prior work on multiprocessor real-time scheduling focuses on independent tasks, dependencies due to non-preemptive sections, suspensions, and pipeline-based precedence constraints are common in practice. In this paper, such complexities are considered in the context of the global earliest-deadline-first scheduling algorithm. It is shown that any periodic task system...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    Feather-Trace: A Light-Weight Event Tracing Toolkit

    The authors present a light-weight event tracing toolkit for real-time operating systems on the Intel x86 platform. Their approach is wait-free, multiprocessor-safe, and introduces very low overhead. Only a single unconditional jump instruction is required to distinguish between enabled and disabled events. As a case study, they traced the locking...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    Integrating Hard/Soft Real-Time Tasks and Best-Effort Jobs on Multiprocessors

    An important trend in computing is the ongoing move towards system- and chip-level parallelism. Because of heat and power issues, it has become increasingly difficult to improve processor performance by increasing clock speeds. Therefore, in order to continue performance improvements, major processor manufacturers, such as Intel, AMD, IBM, and Sun...

    Provided By University of North Alabama

  • White Papers // Jan 2011

    On Measuring the Similarity of Network Hosts: Pitfalls, New Metrics, and Empirical Analyses

    As the scope and scale of network data grows, security practitioners and network operators are increasingly turning to automated data analysis methods to extract meaningful information. Underpinning these methods are distance metrics that represent the similarity between two values or objects. In this paper, the authors argue that many of...

    Provided By University of North Alabama

  • White Papers // May 2011

    An Approach for Automatic Selection of Relevance Features in Intrusion Detection Systems

    In Intrusion Detection Systems the environment data in general depends on many computer network related characteristics called features. However not all of the network features contribute to the discriminating properties of different types of intrusion attacks. Hence the selection of relevance features becomes an important requirement for the accurate and...

    Provided By University of North Alabama

  • White Papers // May 2010

    Decomposing RTT-Unfairness in Transport Protocols

    In this paper, the authors consider RTT-unfairness in most existing end-to-end congestion-control protocols, in which transfers with smaller RTTs are allocated a higher share of the bottleneck bandwidth. They consider the congestion-control mechanisms used by TCP NewReno and identify three aspects that introduce an RTT-based bias in different ways. Past...

    Provided By University of North Alabama

  • White Papers // Sep 2011

    Impact of Cross Traffic Burstiness on the Packet-Scale Paradigm

    The packet-scale paradigm is a novel framework for achieving ultra-high speed congestion control. Due to its reliance on finely-controlled inter-packet gaps, the paradigm is expected to be sensitive to transient burstiness in traffic encountered on bottleneck links. This paper uses a first-principles approach to study the impact of cross traffic...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    A Peer-to-Peer Architecture to Enable Versatile Lookup System Design

    The resource lookup requirements in applications such as web caching, web content search, content distribution, resource sharing, network monitoring and management, and e-commerce have caught the attention of Peer-To-Peer (P2P) distributed systems researchers. Over the past few years, several decentralized P2P lookup system designs have been proposed for addressing these...

    Provided By University of North Alabama

  • White Papers // Jun 2013

    Towards An Understanding of Cloud Computing's Impact On Organizational IT Strategy

    Cloud computing has become a dominant IT trend during the past two years for its potential to remarkably change the technology and business landscape. Although a lot have been discussed, its impacts on organizational IT strategy have not yet been fully addressed. In order to learn how cloud computing is...

    Provided By University of North Alabama

  • White Papers // Sep 2012

    An O(m) Analysis Technique for Supporting Real-Time Self-Suspending Task Systems

    In many real-time and embedded systems, suspension delays may occur when tasks block to access shared resources or interact with external devices. Unfortunately, prior analysis methods for dealing with suspensions are quite pessimistic. In this paper, a novel technique is presented for analyzing soft real-time sporadic self-suspending task systems, for...

    Provided By University of North Alabama

  • White Papers // Apr 2012

    Supporting Soft Real-Time Parallel Applications on Multicore Processors

    The prevalence of multicore processors has resulted in the wider applicability of parallel programming models such as OpenMP and MapReduce. A common goal of running parallel applications implemented under such models is to guarantee bounded response times while maximizing system utilization. Unfortunately, little previous work has been done that can...

    Provided By University of North Alabama

  • White Papers // Sep 2010

    Supporting Soft Real-Time DAG-Based Systems on Multiprocessors With No Utilization Loss

    In work on globally-scheduled real-time multiprocessor systems, analysis is lacking for supporting real-time applications developed using general processing graph models. In this paper, it is shown that bounded deadline tardiness can be ensured for such applications on a multiprocessor with no utilization loss. This result is general: it is applicable...

    Provided By University of North Alabama

  • White Papers // Jan 2010

    Scheduling Suspendable, Pipelined Tasks With Non-Preemptive Sections in Soft Real-Time Multiprocessor Systems

    While most prior work on multiprocessor real-time scheduling focuses on independent tasks, dependencies due to non-preemptive sections, suspensions, and pipeline-based precedence constraints are common in practice. In this paper, such complexities are considered in the context of the global earliest-deadline-first scheduling algorithm. It is shown that any periodic task system...

    Provided By University of North Alabama

  • White Papers // Sep 2009

    Task Scheduling with Self-Suspensions in Soft Real-Time Multiprocessor Systems

    In many real-time systems, tasks interact with external devices that introduce self-suspension delays. Examples of such devices include solid-state and magnetic disks and network cards. Delays introduced by such devices can be moderate unfortunately, such delays quite negatively impact schedulability in real-time systems if deadline misses cannot be tolerated. In...

    Provided By University of North Alabama

  • White Papers // Jul 2012

    The OMLP Family of Optimal Multiprocessor Real-Time Locking Protocols

    This paper presents the first suspsension-based multiprocessor real-time locking protocols with asymptotically optimal blocking bounds (under certain analysis assumptions). These protocols can be applied under any global, clustered, or partitioned job-level fixed-priority scheduler and support mutual exclusion, reader-writer exclusion, and k-exclusion constraints. Notably, the reader-writer and k-exclusion protocols are the...

    Provided By University of North Alabama

  • White Papers // Sep 2011

    Soft Real-Time on Multiprocessors: Are Analysis-Based Schedulers ReallyWorth It?

    The evolution of multicore platforms has led to much recent work on multiprocessor scheduling techniques for soft real-time workloads. However, end users routinely run such workloads atop general-purpose operating systems with seemingly good results, albeit typically on over-provisioned systems. This raises the question: when, if ever, is the use of...

    Provided By University of North Alabama

  • White Papers // Apr 2011

    Is Semi-Partitioned Scheduling Practical?

    Semi-partitioned schedulers are - in theory - a particularly promising category of multiprocessor real-time scheduling algorithms. Unfortunately, issues pertaining to their implementation have not been investigated in detail, so their practical viability remains unclear. In this paper, the practical merit of three EDF-based semi-partitioned algorithms is accessed via an experimental...

    Provided By University of North Alabama

  • White Papers // Aug 2010

    Optimality Results for Multiprocessor Real-Time Locking

    When locking protocols are used in real-time systems, bounds on blocking times are required when ensuring timing constraints. While the term "Blocking" is well-understood in the context of uniprocessor real-time systems, the same is not true in the multiprocessor case. In this paper, two definitions of blocking are presented that...

    Provided By University of North Alabama

  • White Papers // Sep 2010

    An Empirical Comparison of Global, Partitioned, and Clustered Multiprocessor EDF Schedulers

    As multicore platforms become ever larger, overhead-related factors play a greater role in determining which real-time scheduling algorithms are preferable. In this paper, such factors are investigated through an empirical comparison of global, partitioned, and clustered EDF scheduling algorithms on a 24-core Intel system. On this platform, global EDF proved...

    Provided By University of North Alabama

  • White Papers // Sep 2009

    On the Implementation of Global Real-Time Schedulers

    An empirical study of implementation tradeoffs (choice of ready queue implementation, quantum-driven vs. event-driven scheduling, and interrupt handling strategy) affecting global real-time schedulers, and in particular global EDF, is presented. This study, conducted using UNC's Linux-based LITMUSRT on Sun's Niagara platform, suggests that implementation tradeoffs can impact schedulability as profoundly...

    Provided By University of North Alabama

  • White Papers // Apr 2009

    Reader-Writer Synchronization for Shared-Memory Multiprocessor Real-Time Systems

    Reader preference, writer preference, and task-fair reader-writer locks are shown to cause undue blocking in multiprocessor real-time systems. A new phase-fair reader-writer lock is proposed as an alternative that significantly reduces worst-case blocking for readers and an efficient local-spin implementation is provided. Both task- and phase-fair locks are evaluated and...

    Provided By University of North Alabama

  • White Papers // Apr 2009

    Multicore Operating-System Support for Mixed Criticality

    Ongoing research is discussed on the development of operating-system support for enabling mixed-criticality workloads to be supported on multicore platforms. This paper is motivated by avionics systems in which such workloads occur. In the mixed-criticality workload model that is considered, task execution costs may be determined using more-stringent methods at...

    Provided By University of North Alabama

  • White Papers // Jan 2013

    A Flexible Real-Time Locking Protocol for Multiprocessors

    Real-time scheduling algorithms for multiprocessor systems have been the subject of considerable recent interest. For such an algorithm to be truly useful in practice, support for semaphore-based locking must be provided. However, for many global scheduling algorithms, no such mechanisms have been proposed. Furthermore, in the partitioned case, most prior...

    Provided By University of North Alabama

  • White Papers // Oct 2010

    Assessing Students' Structured Programming Skills With Java: The Blue, Berry, and Blueberry Assignment

    Java is an object-oriented programming language. From a software engineering perspective, object-oriented design and programming is used at the architectural design, and structured design and programming is used at the detailed design within methods. As such, structured programming skills are fundamental to more advanced object-oriented programming concepts. Structured programming uses...

    Provided By University of North Alabama

  • White Papers // Apr 2008

    Simple Calibration of Non-overlapping Cameras with a Mirror

    Calibrating a network of cameras with non-overlapping views is an important and challenging problem in computer vision. In this paper, the authors present a novel technique for camera calibration using a planar mirror. They overcame the need for all cameras to see a common calibration object directly by allowing them...

    Provided By University of North Alabama

  • White Papers // Jun 2012

    Security and Usability Challenges of Moving-Object CAPTCHAs: Decoding Codewords in Motion

    The authors explore the robustness and usability of moving-image object recognition (video) captchas, designing and implementing automated attacks based on computer vision techniques. Their approach is suitable for broad classes of moving-image captchas involving rigid objects. They first present an attack that defeats instances of such a captcha (NuCaptcha) representing...

    Provided By University of North Alabama

  • White Papers // Oct 2010

    A Simple Abstraction for Data Modeling

    The problems that scientists face in creating well designed databases intersect with the concerns of data curation. Entity-relationship modeling and its variants have been the basis of most relational data modeling for decades. However, these abstractions and the relational model itself are intricate and have proved not to be very...

    Provided By University of North Alabama

  • White Papers // May 2009

    Statistics & Clustering Based Framework for Efficient XACML Policy Evaluation

    The adoption of XACML as the standard for specifying access control policies for various applications, especially web services is vastly increasing. A policy evaluation engine can easily become a bottleneck when enforcing large policies. In this paper, the authors propose an adaptive approach for XACML policy optimization. They proposed a...

    Provided By University of North Alabama

  • White Papers // May 2010

    User Centric Policy Management in Online Social Networks

    Online social networking sites are experiencing tremendous user growth with hundreds of millions of active users. As a result, there is a tremendous amount of user profile data online, e.g., name, birth date, etc. Protecting this data is a challenge. The task of access policy composition is a tedious and...

    Provided By University of North Alabama

  • White Papers // Jul 2011

    ROAuth: Recommendation Based Open Authorization

    Many major online platforms such as Facebook, Google, and Twitter, provide an open Application Programming Interface which allows third party applications to access user resources. The Open Authorization protocol (OAuth) was introduced as a secure and efficient method for authorizing third party applications without releasing a user's access credentials. However,...

    Provided By University of North Alabama

  • White Papers // Jun 2012

    Anomaly Discovery and Resolution in MySQL Access Control Policies

    Managing hierarchical and ne grained DBMS policies for a large number of users is a challenging task and it increases the probability of introducing mis-configurations and anomalies. In this paper, the authors present a formal approach to discover anomalies in database policies using Binary Decision Diagrams (BDDs) which allow finer...

    Provided By University of North Alabama

  • White Papers // Feb 2010

    Virtual Multiprocessor Platforms: Specification and Use

    The Parallel Supply Function (PSF) is proposed for representing the computing capabilities offered by virtual platforms implemented atop identical multiprocessors. It is shown that this abstraction is strictly more powerful than previously-proposed ones, from the perspective of more accurately representing the inherent parallelism of the provided computing capabilities. Sufficient tests...

    Provided By University of North Alabama

  • White Papers // Apr 2010

    The Parallel Supply Function Abstraction for a Virtual Multiprocessor

    A new abstraction - the Parallel Supply Function (PSF) - is proposed for representing the computing capabilities offered by virtual platforms implemented atop identical multiprocessors. It is shown that this abstraction is strictly more powerful than previously-proposed ones, from the perspective of more accurately representing the inherent parallelism of the...

    Provided By University of North Alabama

  • White Papers // Mar 2013

    Just-In-Time Code Reuse: On the Effectiveness of Fine-Grained Address Space Layout Randomization

    Fine-grained Address Space Layout Randomization (ASLR) has recently been proposed as a method of efficiently mitigating runtime attacks. In this paper, the authors introduce the design and implementation of a framework based on a novel attack strategy, dubbed just-in-time code reuse that undermines the benefits of fine-grained ASLR. Specifically, they...

    Provided By University of North Alabama

  • White Papers // Aug 2006

    Global Static-Priority Scheduling of Sporadic Task Systems on Multiprocessor Platforms

    Over the years, the sporadic task model has proven remarkably useful for the modeling of recurring processes that occur in hard-real-time systems. The multiprocessor scheduling of collections of real-time jobs is considered. Sufficient conditions are derived for determining whether a specified system meets all deadlines when scheduled by a static-priority...

    Provided By University of North Alabama

  • White Papers // Jan 2011

    Partitioned Real-Time Scheduling on Heterogeneous Shared-Memory Multiprocessors

    The authors consider several real-time scheduling problems on heterogeneous multiprocessor platforms, in which the different processors share a common memory pool. These include scheduling a collection of implicit-deadline sporadic tasks with the objective of meeting all deadlines; and scheduling a collection of independent jobs with the objective of minimizing the...

    Provided By University of North Alabama

  • White Papers // Apr 2009

    On the Design and Implementation of a Cache-Aware Multicore Real-Time Scheduler

    Multicore architectures, which contain multiple processing cores on a single chip, have been adopted by most chip manufacturers. Dual-core chips are commonplace, and numerous four- and eight-core options exist. In this paper, the authors assume that systems are organized into Multi-Threaded Tasks (MTTs), where each MTT consists of periodic (sequential)...

    Provided By University of North Alabama

  • White Papers // Apr 2008

    Cache-Aware Real-Time Scheduling on Multicore Platforms: Heuristics and a Case Study

    Multicore architectures, which have multiple processing units on a single chip, have been adopted by most chip manufacturers. Most such chips contain on-chip caches that are shared by some or all of the cores on the chip. To effectively use the available processing resources on such platforms, scheduling methods must...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Soft Real-Time Scheduling on Performance Asymmetric Multicore Platforms

    In this paper, the authors discuss an approach for supporting soft real-time periodic tasks in Linux on performance Asymmetric Multicore Platforms (AMPs). Such architectures consist of a large number of processing units on one or several chips, where each processing unit is capable of executing the same instruction set at...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Parallel Real-Time Task Scheduling on Multicore Platforms

    Multicore architectures, which include several processors on a single chip, are being widely touted as a solution to the \"Thermal roadblock\"” imposed by single-core designs. Several chip makers have released dual-core chips, and a few designs with more than two cores have been announced as well. The authors propose a...

    Provided By University of North Alabama

  • White Papers // Jan 2014

    Real-Time Scheduling on Multicore Platforms

    Multicore architectures, which have multiple processing units on a single chip, are widely viewed as a way to achieve higher processor performance, given that thermal and power problems impose limits on the performance of single-core designs. Accordingly, several chip manufacturers have already released, or will soon release, chips with dual...

    Provided By University of North Alabama