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101 Regehr, JohnHierarchical schedulers, performance guarantees, and resource managementAn attractive approach to scheduling applications with diverse CPU scheduling requirements is to use different schedulers for different applications. For example: real-time schedulers allow applications to perform computations before deadlines, time-sharing schedulers provide high throughput for com...1999-01-01
102 Regehr, JohnIssues in using commodity operating systems for time-dependent tasks: experiences from a study of windows NTThis paper presents a snapshot of early results from a study of Windows NT aimed at understanding and improving its limitations when used for time-dependent tasks, such as those that arise for audio and video processing. Clearly there are time scales for which it can achieve effectively perfect reli...1998-01-01
103 Widanagamaachchi, Wathsala Nayomi; Pascucci, ValerioImage registrationImage Registration is the process of overlaying two or more images of the same scene, taken at different times, from different viewpoints and/or by different sensors.
104 Johnson, Christopher R.Optimizing Inverse Electrocardiographic Problem: Hybrid and High-Order Finite Element MethodOne type of inverse problems in electrocardiography (ECG) is to non-invasively reconstruct epicardial electric potentials from body-surface measurements. We study how to design the finite element discretization of such problem, so as to optimize the conditioning and stability of the resulting num...
105 Regehr, JohnSome guidelines for proportional share CPU scheduling in general-purpose operating systemsOur premise is that since there already exists a large, mature body of literature on real-time scheduling in general-purpose operating systems, it is time to spend more effort deciding which of these algorithms should be used and when, and less effort on generating new algorithms. In this paper we f...2001-01-01
106 Regehr, JohnSurviving sensor network software faultsWe describe Neutron, a version of the TinyOS operating system that efficiently recovers from memory safety bugs. Where existing schemes reboot an entire node on an error, Neutron's compiler and runtime extensions divide programs into recovery units and reboot only the faulting unit. The TinyOS kerne...2009-01-01
107 Regehr, JohnSwarm testingSwarm testing is a novel and inexpensive way to improve the diversity of test cases generated during random testing. Increased diversity leads to improved coverage and fault detection. In swarm testing, the usual practice of potentially including all features in every test case is abandoned. Rather,...2012-01-01
108 Regehr, JohnScheduling Tasks with mixed preemption relations for robustness to timing faultsThis paper introduces and shows how to schedule two novel scheduling abstractions that overcome limitations of existing work on preemption threshold scheduling. The abstractions are task clusters, groups of tasks that are mutually non-preemptible by design, and task barriers, which partition the tas...2002-01-01
109 Regehr, JohnSafe and structured use of interrupts in real-time and embedded softwareWhile developing embedded and real-time systems, it is usually necessary to write code that handles interrupts, or code the interacts with interrupt handlers. Interrupts are indispensable because they use hardware support to reduce both the latency and overhead of event detection, when compared to p...2007-01-01
110 Regehr, JohnRuntime verification for wireless sensor network applicationsWireless sensor networks are widely used to detect environment information that is not accessible by human. Developing such networks however requires low-level programming. The lack of sophisticated debugging tools for sensor networks makes it difficult to make the connection between a high-level fu...2008-01-01
111 Regehr, JohnTest-case reduction for C compiler bugsTo report a compiler bug, one must often find a small test case that triggers the bug. The existing approach to automated test-case reduction, delta debugging, works by removing substrings of the original input; the result is a concatenation of substrings that delta cannot remove. We have found this...2012-01-01
112 Regehr, JohnTesting static analyzers with randomly generated programsStatic analyzers should be correct. We used the random C-program generator Csmith, initially intended to test C compilers, to test parts of the Frama-C static analysis platform. Although Frama-C was already relatively mature at that point, fifty bugs were found and fixed during the process, in the f...2012-01-01
113 Regehr, JohnPluggable abstract domains for analyzing embedded softwareMany abstract value domains such as intervals, bitwise, constants, and value-sets have been developed to support dataflow analysis. Different domains offer alternative tradeoffs between analysis speed and precision. Furthermore, some domains are a better match for certain kinds of code than others. ...2006-01-01
114 Regehr, JohnAugmented CPU reservations: towards predictable execution on general-purpose operating systemsOne problem with performing soft real-time computations on general-purpose operating systems is that these OSs may spend significant amounts of time in the kernel instead of performing work on behalf of the application that is nominally scheduled: the OS effectively steals time from the running appl...2001-01-01
115 Hansen, Charles D.Combined surface and volumetric occlusion shadingIn this paper, a method for interactive direct volume rendering is proposed that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts....2012-01-01
116 Regehr, JohnARMor: fully verified software fault isolationWe have designed and implemented ARMor, a system that uses software fault isolation (SFI) to sandbox application code running on small embedded processors. Sandboxing can be used to protect components such as the RTOS and critical control loops from other, less-trusted components. ARMor guarantees m...2011-01-01
117 Zhao, Lu; Regehr, JohnComparing program logics for reasoning about safety propertiesTo prove memory write and controls transfers do not interfere with other programs in embedded systems. Hoare Logic with Bale Predicate; Hoare Logic with Separation Conjunction.2010-10-06
118 Schott, Mathias; Hansen, Charles DA directional occlusion shading model for interactive direct volume renderingVolumetric rendering is widely used to examine 3D scalar fields Key aspect: provide perceptual cues to aid in understanding the data set Shading models with natural lighting conditions better convey depth information and spatial relationships Traditionally require considerable (pre)computatio...
119 Regehr, JohnA practical logic framework for verifying safety properties of executablesWe present a novel program logic, Lf , which is designed on top of a Hoare logic, but is simpler, more flexible and more scalable. Based on Lf , we develop a framework for automatically verifying safety properties of executables. It utilizes a whole-program interprocedural abstract interpretation to...2011-01-01
120 Regehr, JohnDeriving abstract transfer functions for analyzing embedded softwareThis paper addresses the problem of creating abstract transfer functions supporting dataflow analyses. Writing these functions by hand is problematic: transfer functions are difficult to understand, difficult to make precise, and difficult to debug. Bugs in transfer functions are particularly seriou...2006-01-01
121 Regehr, JohnDynamic CPU management for real-time, middleware-based systemsMany real-world distributed, real-time, embedded (DRE) systems, such as multi-agent military applications, are built using commercially available operating systems, middleware, and collections of pre-existing software. The complexity of these systems makes it difficult to ensure that they maintain h...2004-01-01
122 Regehr, JohnEdicts: implementing features with flexible binding timesIn a software product line, the binding time of a feature is the time at which one decides to include or exclude a feature from a product. Typical binding site implementations are intended to support a single binding time only, e.g., compile time or run time. Sometimes, however, a product line must...2008-01-01
123 Regehr, JohnCPU reservations and time constraints: implementation experience on windows NTThis paper presents an implementation of scheduling abstractions originally developed for the Rialto real-time operating system within a research version of Windows NT called Rialto/NT. These abstractions, CPU Reservations and Time Constraints, as described in the 1997 SOSP paper [Jones et al. 97], ...1999-01-01
124 Regehr, JohnFrom the editor: real-time and embedded systems--teaching reliabilityCan we teach students to build reliable embedded software? Although it would be rash to say that a general agreement exists on how to teach embedded systems, there's certainly a growing understanding of the issues. For example, the excellent August 2005 issue of ACM Transactions on Embedded Computin...2006-01-01
125 Regehr, JohnInferring scheduling behavior with hourglassAlthough computer programs explicitly represent data values, time values are usually implicit. This makes it difficult to analyze and debug real-time programs whose correctness depends partially on the time at which results are computed. This paper shows how to use Hourglass, an instrumented, synthe...2002-01-01
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