Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 21 of 21
Full-Text Articles in Computer Engineering
Supporting Collaboration In Mobile Environments, Rohan Sen
Supporting Collaboration In Mobile Environments, Rohan Sen
All Computer Science and Engineering Research
Continued rapid improvements in the hardware capabilities of mobile computing devices is driving a parallel need for a paradigm shift in software design for such devices with the aim of ushering in new classes of software applications for devices of the future. One such class of software application is collaborative applications that seem to reduce the burden and overhead of collaborations on human users by providing automated computational support for the more mundane and mechanical aspects of a cooperative effort. This dissertation addresses the research and software engineering questions associated with building a workflow-based collaboration system that can operate across …
Modeling Timed Component-Based Real-Time Systems, Huang-Ming Huang, Christopher Gill
Modeling Timed Component-Based Real-Time Systems, Huang-Ming Huang, Christopher Gill
All Computer Science and Engineering Research
Component based middleware helps to facilitate software reuse by separating application-specific concerns into modular components that are shielded from the concerns of other components and from the common concerns addressed by underlying middleware services. In real-time systems, concerns such as invocation rates, execution latencies, deadlines, and concurrency semantics cross-cut multiple component and middleware abstractions. Thus, the verification of these systems must consider features of the application components (e.g., their execution latencies and relative invocation rates) and of the supporting middleware (e.g., concurrency and scheduling) together. However, existing approaches only address a sub-set of the features that must be modeled in …
Real-Time Performance And Middleware On Multicore Linux Platforms, Yuanfang Zhang, Christopher Gill, Chenyang Lu
Real-Time Performance And Middleware On Multicore Linux Platforms, Yuanfang Zhang, Christopher Gill, Chenyang Lu
All Computer Science and Engineering Research
An increasing number of distributed real-time applications are running on multicore platforms. However, existing real-time middleware (e.g., Real-Time CORBA) lacks support for scheduling soft real-time tasks on multicore platforms while guaranteeing their time constraints will be satisfied. This paper makes three contributions to the state of the art in real-time system software for multicore platforms. First, it offers what is to our knowledge the first experimental analysis of real-time performance for vanilla Linux primitives on multicore platforms. Second, it presents MC-ORB, the first real-time object request broker (ORB), designed to exploit the features of multicore platforms, with admission control and …
Multi-Application Deployment In Integrated Sensing Systems Based On Quality Of Monitoring, Sangeeta Bhattacharya, Abusayeed Saifullah, Chenyang Lu, Gruia-Catalin Roman
Multi-Application Deployment In Integrated Sensing Systems Based On Quality Of Monitoring, Sangeeta Bhattacharya, Abusayeed Saifullah, Chenyang Lu, Gruia-Catalin Roman
All Computer Science and Engineering Research
No abstract provided.
Software And Hardware Acceleration Of The Genomic Motif Finding Tool Phylonet, Justin Brown
Software And Hardware Acceleration Of The Genomic Motif Finding Tool Phylonet, Justin Brown
All Computer Science and Engineering Research
No abstract provided.
Animal Microrna Target Prediction By Incorporating Diverse Sequence-Specific Determinants, Yun Zheng, Weixiong Zhang
Animal Microrna Target Prediction By Incorporating Diverse Sequence-Specific Determinants, Yun Zheng, Weixiong Zhang
All Computer Science and Engineering Research
More recent evidence has shown that access of animal microRNAs (miRNAs) to their complementary sites in target mRNAs is determined by more sequence-specific determinants than the seed regions in the 5' end of miRNAs. Although these factors have been shown to be related to the repressive power of miRNAs and used, in separate programs, to predict the efficacy of miRNA complementary sites, it remains unclear whether these factors can help to improve miRNA target prediction. We develop a new miRNA target prediction algorithm, called Hitsensor, by incorporating more sequence-specific features that determine complementarities between miRNAs and their targets, in addition …
Reconfigurable Real-Time Middleware For Distributed Cyber-Physical Systems With Aperiodic Events, Yuanfang Zhang, Christopher Gill, Chenyang Lu
Reconfigurable Real-Time Middleware For Distributed Cyber-Physical Systems With Aperiodic Events, Yuanfang Zhang, Christopher Gill, Chenyang Lu
All Computer Science and Engineering Research
Different distributed cyber-physical systems must handle aperiodic and periodic events with diverse requirements. While existing real-time middleware such as Real-Time CORBA has shown promise as a platform for distributed systems with time constraints, it lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different cyber-physical systems with both aperiodic and periodic events. The primary contribution of this work is the design, implementation and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic event handling in distributed cyber-physical systems. Empirical results demonstrate the need for, …
Deciding Joinability Modulo Ground Equations In Operational Type Theory, Adam Petcher, Aaron Stump
Deciding Joinability Modulo Ground Equations In Operational Type Theory, Adam Petcher, Aaron Stump
All Computer Science and Engineering Research
Operational Type Theory (OpTT) can be used to construct and check proofs related to programs, but the development of these proofs can be somewhat tedious. An algorithm is presented that can be used to automatically generate proofs of equality in OpTT. The algorithm takes as input a set of ground equations and two terms that should be tested for joinability modulo the supplied ground equations. The algorithm will equate the terms if and only if there exists an OpTT proof that can equate the two terms using only the proof rules related to evaluation under the operational semantics, symmetry, transitivity, …
A Holistic Approach To Decentralized Structural Damage Localization Using Wireless Sensor Networks, Gregory Hackmann, Fei Sun, Nestor Castaneda, Chenyang Lu, Shirley Dyke
A Holistic Approach To Decentralized Structural Damage Localization Using Wireless Sensor Networks, Gregory Hackmann, Fei Sun, Nestor Castaneda, Chenyang Lu, Shirley Dyke
All Computer Science and Engineering Research
Wireless sensor networks (WSNs) have become an increasingly compelling platform for Structural Health Monitoring (SHM) applications, since they can be installed relatively inexpensively onto existing infrastructure. Existing approaches to SHM in WSNs typically address computing system issues or structural engineering techniques, but not both in conjunction. In this paper, we propose a holistic approach to SHM that integrates a decentralized computing architecture with the Damage Localization Assurance Criterion algorithm. In contrast to centralized approaches that require transporting large amounts of sensor data to a base station, our system pushes the execution of portions of the damage localization algorithm onto the …
Scheduling Design And Verification For Open Soft Real-Time Systems, Robert Glaubius, Terry Tidwell, William D. Smart, Christopher Gill
Scheduling Design And Verification For Open Soft Real-Time Systems, Robert Glaubius, Terry Tidwell, William D. Smart, Christopher Gill
All Computer Science and Engineering Research
Open soft real-time systems, such as mobile robots, experience unpredictable interactions with their environments and yet must respond both adaptively and with reasonable temporal predictability. New scheduling approaches are needed to address the demands of such systems, in which many of the assumptions made by traditional real-time scheduling theory do not hold. In previous work we established foundations for a scheduling policy design and verification approach for open soft real-time systems, that can use different decision models, e.g., a Markov Decision Process (MDP), to capture the nuances of their scheduling semantics. However, several important refinements to the preliminary techniques developed …
Local Neighborhoods For Shape Classification And Normal Estimation, Cindy Grimm, William Smart
Local Neighborhoods For Shape Classification And Normal Estimation, Cindy Grimm, William Smart
All Computer Science and Engineering Research
We introduce the concept of local neighborhoods, a generalization of the one-ring on a mesh to unlabeled 3D data points arising from sampling a 2D surface embedded in 3D. The local neighborhood supports both local shape classification and robust normal estimation. In particular, local neighborhoods out-perform traditional approaches in unevenly sampled, curved regions. We show that the local neighborhood can be used in place of a full mesh structure for applications such as smoothing, moving least-squares reconstruction, and parameterization. Longer version of paper submitted to CAGD
Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thaker
Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thaker
All Computer Science and Engineering Research
Existing off-line schedulability analysis for real-time systems can only handle periodic or sporadic tasks with known minimum inter-arrival times. Modeling sporadic tasks with fixed minimum inter-arrival times is a poor approximation for systems in which tasks arrive in bursts, but have longer intervals between the bursts. In such cases, schedulability analysis based on the existing sporadic task model is pessimistic and seriously overestimates the task's time demand. In this paper, we propose a generalized sporadic task model that characterizes arrival times more precisely than the traditional sporadic task model, and we develop a corresponding schedulability analysis that computes tighter bounds …
A Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thakar
A Practical Schedulability Analysis For Generalized Sporadic Tasks In Distributed Real-Time Systems, Yuanfang Zhang, Donald K. Krecker, Christopher Gill, Chenyang Lu, Guatam H. Thakar
All Computer Science and Engineering Research
Existing off-line schedulability analysis for real-time systems can only handle periodic or sporadic tasks with known minimum inter-arrival times. Modeling sporadic tasks with fixed minimum inter-arrival times is a poor approximation for systems in which tasks arrive in bursts, but have longer intervals between the bursts. In such cases, schedulability analysis based on the existing sporadic task model is pessimistic and seriously overestimates the task's time demand. In this paper, we propose a generalized sporadic task model that characterizes arrival times more precisely than the traditional sporadic task model, and we develop a corresponding schedulability analysis that computes tighter bounds …
Scheduling For Reliable Execution In Autonomic Systems, Terry Tidwell, Robert Glaubius, Christopher Gill, William D. Smart
Scheduling For Reliable Execution In Autonomic Systems, Terry Tidwell, Robert Glaubius, Christopher Gill, William D. Smart
All Computer Science and Engineering Research
Scheduling the execution of multiple concurrent tasks on shared resources such as CPUs and network links is essential to ensuring the reliable operation of many autonomic systems. Well known techniques such as rate-monotonic scheduling can offer rigorous timing and preemption guarantees, but only under assumptions (i.e., a fixed set of tasks with well-known execution times and invocation rates) that do not hold in many autonomic systems. New hierarchical scheduling techniques are better suited to enforce the more flexible execution constraints and enforcement mechanisms that are required for autonomic systems, but a rigorous foundation for verifying and enforcing concurrency and timing …
Financial Monte Carlo Simulation On Architecturally Diverse Systems, Naveen Singla, Michael Hall, Berkley Shands, Roger D. Chamberlain
Financial Monte Carlo Simulation On Architecturally Diverse Systems, Naveen Singla, Michael Hall, Berkley Shands, Roger D. Chamberlain
All Computer Science and Engineering Research
Computational finance relies heavily on the use of Monte Carlo simulation techniques. However, Monte Carlo simulation is computationally very demanding. We demonstrate the use of architecturally diverse systems to accelerate the performance of these simulations, exploiting both graphics processing units and field-programmable gate arrays. Performance results include a speedup of 74× relative to an 8 core multiprocessor system (180× relative to a single processor core).
Partial Program Admission By Path Enumeration, Michael Wilson, Ron Cytron, Jon Turner
Partial Program Admission By Path Enumeration, Michael Wilson, Ron Cytron, Jon Turner
All Computer Science and Engineering Research
Real-time systems on non-preemptive platforms require a means of bounding the execution time of programs for admission purposes. Worst-Case Execution Time (WCET) is most commonly used to bound program execution time. While bounding a program's WCET statically is possible, computing its true WCET is difficult without significant semantic knowledge. We present an algorithm for partial program admission, suited for non-preemptive platforms, using dynamic programming to perform explicit enumeration of program paths. Paths - possible or not - are bounded by the available execution time and admitted on a path-by-path basis without requiring semantic knowledge of the program beyond its Control …
Reliable Data Collection From Mobile Users For Real-Time Clinical Monitoring, Octav Chipara, Christopher Brooks, Sangeeta Bhattacharya, Chenyang Lu
Reliable Data Collection From Mobile Users For Real-Time Clinical Monitoring, Octav Chipara, Christopher Brooks, Sangeeta Bhattacharya, Chenyang Lu
All Computer Science and Engineering Research
Real-time patient monitoring is critical to early detection of clinical patient deterioration in general hospital wards. A key challenge in such applications is to reliably deliver sensor data from mobile patients. We present an empirical analysis on the reliability of data collection from wireless pulse oximeters attached to users. We observe that most packet loss occur from mobile users to their first-hop relays. Based on this insight we developed the Dynamic Relay Association Protocol (DRAP), a simple and effective mechanism for dynamically discovering the right relays for wireless sensors attached to mobile users. DRAP enables highly reliable data collection from …
Transcriptome Analysis Of Alzheimer's Disease Identifies Links To Cardiovascular Disease, Monika Ray, Jianhua Ruan, Weixiong Zhang
Transcriptome Analysis Of Alzheimer's Disease Identifies Links To Cardiovascular Disease, Monika Ray, Jianhua Ruan, Weixiong Zhang
All Computer Science and Engineering Research
No abstract provided.
Verification Of Component-Based Distributed Real-Time Systems, Huang-Ming Huang, Christopher Gill
Verification Of Component-Based Distributed Real-Time Systems, Huang-Ming Huang, Christopher Gill
All Computer Science and Engineering Research
Component-based software architectures enable reuse by separating application-specific concerns into modular components that are shielded from each other and from common concerns addressed by underlying services. Even so, concerns such as invocation rates, execution latencies, deadlines, and concurrency and scheduling semantics still cross-cut component boundaries in many real-time systems. Verification of these systems therefore must consider how composition of components relates to timing, resource utilization, and other properties. However, existing approaches only address a sub-set of the concerns that must be modeled in component-based distributed real-time systems, and a new more comprehensive approach is thus needed. To address that need, …
Faster Optimal State-Space Search With Graph Decomposition And Reduced Expansion, Yixin Chen
Faster Optimal State-Space Search With Graph Decomposition And Reduced Expansion, Yixin Chen
All Computer Science and Engineering Research
Traditional AI search methods, such as BFS, DFS, and A*, look for a path from a starting state to the goal in a state space most typically modelled as a directed graph. Prohibitively large sizes of the state space graphs make optimal search difficult. A key observation, as manifested by the SAS+ formalism for planning, is that most commonly a state-space graph is well structured as the Cartesian product of several small subgraphs. This paper proposes novel search algorithms that exploit such structure. The results reveal that standard search algorithms may explore many redundant paths. Our algorithms provide an automatic …
Flexible Service Provisioning For Heterogeneous Sensor Networks, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu
Flexible Service Provisioning For Heterogeneous Sensor Networks, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu
All Computer Science and Engineering Research
This paper presents Servilla, a highly flexible service provisioning framework for heterogeneous wireless sensor networks. Its service-oriented programming model and middleware enable developers to construct platform-independent applications over a dynamic set of devices with diverse computational resources and sensors. A salient feature of Servilla is its support for dynamic discovery and binding to local and remote services, which enables flexible and energy-efficient in-network collaboration among heterogeneous devices. Furthermore, Servilla provides a modular middleware architecture that can be easily tailored for devices with a wide range of resources, allowing even resource-limited devices to provide services and leverage resource-rich devices for in-network …