53244399
RETOS: resilient, expandable, and threaded operating system for wireless sensor networks
accelerated bythereadily-available hardware platforms, aswellas Thispaperpresents thedesign principles, implementation, and coresystem software suchassensornodeoperating systems in evaluation oftheRETOSoperating system whichisspecifically particular. Fromtheearly days, mucheffort hasbeengiven to developed formicrosensor nodes. RETOS hasfourdistinctdevelop efficient andyetcomplete operating systems formicro objectives, which aretoprovide (1) amultithreaded programming sensornodes. Forinstance, TinyOS [1] hashistorically beenusedby interface, (2)system resiliency, (3)kerelextensibility with manypractitioners inthefield andeven advocated as "the" dynamic reconfiguration, and (4)WSN-oriented network operating system forWSN.Otheroperating systems suchas
46451597
The RETOS operating system: kernel, tools and applications
6005789
Optimizing SMT Processors for High Single-Thread Performance
Simultaneous Multithreading (SMT) processors achieve high processor throughput at the expense of single-thread performance. This paper investigates resource allocation policies for SMT processors that preserve, as much as possible, the single-thread performance of designated “foreground” threads, while still permitting other “background” threads to share resources. Since background threads o ns uch an SMT machine have an ear-zero performance impact on foreground threads, we refer to the background threads as transparent threads. Transparent threads are ideal for performing low-priority or non-critical computations, with applications in process scheduling, subordinate multithreading, and on-line performance monitoring. To realize transparent threads, we propose three mechanisms for maintaining the transparency of background threads: slot prioritization, background thread instruction-window partitioning, and background thread flushing. In addition, we propose three mechanisms to boost background thread performance without sacrificing transparency: aggressive fetch partitioning, foreground thread instruction-window partitioning, and foreground thread flushing. We implement our mechanisms on a detailed simulator of an SMT processor, and evaluate them using 8 benchmarks, including 7 from the SPEC CPU2000 suite. Our results show when cache and branch predictor interference are factored out, background threads introduce less than 1% performance degradation on the foreground thread. Furthermore, maintaining the transparency of background threads reduces their throughput by only 23% relative to an equal priority scheme. To demonstrate the usefulness of transparent threads, we study Transparent Software Prefetching (TSP), an implementation of software data prefetching using transparent threads. Due to its near-zero overhead, TSP enables prefetch instrumentation for all loads in a program, eliminating the need for profiling. TSP, without any profile information, achieves a 9.41% gain across 6 SPEC benchmarks, whereas conventional software prefetching guided by cache-miss profiles increases performance by only 2.47%.
26521398
Advanced Stochastic Host State Modeling to Reliable Computation in Global Computing Environment
To design a stable global computing environment supporting reliable job execution and covering unanticipated state changes of hosts, the dynamic characteristics (i.e. volatilities) of hosts should be considered. Since a host is not dedicated to the system, voluntary hosts are free to leave and join autonomously in the middle of execution. As current systems do not relate volatility to a scheduling procedure, global computing systems suffer from performance degradation, reliability loss, job interruption, and execution time delays. For dependable computation, we propose Advanced Stochastic Host State Modeling (ASHSM), which is based on Markov model relating to execution availability quantifying duration and regularity of execution patterns of each host. Through the model, the system predicts desktop activities and allocates jobs according to the host features. Furthermore ASHSM alleviates unreliability due to unstable resource provision and job suspension during execution
16841890
Scheduling Scheme based on Dedication Rate in Volunteer Computing Environment
A volunteer node can join and leave a volunteer computing system freely. However, existing volunteer computing systems suffer from interruptions of job execution, delays of execution time, and increases of total execution time, since they do not consider dynamic scheduling properties (i.e. volatilities), such as leave, join, and suspension. Therefore, dynamic execution properties of volunteer node should be considered in scheduling schemes, in order to design a stable and reliable volunteer computing system. This paper proposes a new scheduling scheme based on the dedication rate (DR), which reflects the dynamic properties of a volunteer. The scheduling scheme improves the completeness and reliability of execution, while also decreasing delay and total execution time. In addition, an implementation of the proposed scheduling scheme on top of Korea@Home is described, as well as performance evaluation
46325531
A utility range-based interactive group support system for multiattribute decision making
Abstract This research suggests an interactive procedure for solving a multiattribute group decision problem using a range-typed utility information, and develops an interactive group support system (RINGS) to implement some capabilities of the procedure. It is often difficult for group members to articulate their preferences with cardinal values, instead they prefer to give incomplete information only. Utility ranges are obtained by solving linear programming problems with incompletely specified information. RINGS finds out conflicting opinions among group members, compares each member's preferences with the others’, and suggests a direction for consensus seeking. The procedure of RINGS utilizes range-typed visual information, which helps the group reach a consensus. RINGS has several facilities like graphic user interface, model base, and database, so the total time to reach a group consensus is reduced. The evaluation of information systems is illustrated as a demonstration of some capabilities of RINGS. Scope and purpose This paper deals with the multiple attribute decision-making problem using a separable linear programming technique when group decision makers give only their incomplete information about the attribute weight and alternative value. The utility range for individual decision maker is calculated from each decision maker's incomplete information, and the utility range for group decision makers is obtained from those of individual decision makers. An interactive procedure for establishing a group's pairwise dominance relations with a group's utility range is described, and an interactive group support system (RINGS) is developed to implement the procedure. A case study about the evaluation of information systems is illustrated as a demonstration of some capabilities of RINGS.
19996434
A multi-material virtual prototyping system
Abstract This paper proposes a multi-material virtual prototyping system for digital fabrication of heterogeneous prototypes. It consists mainly of a topological hierarchy-sorting algorithm for processing slice contours, and a virtual simulation system for visualisation and optimisation of multi-material layered manufacturing (MMLM) processes. The topological hierarchy-sorting algorithm processes the hierarchy relationship of complex slice contours. It builds a parent-and-child list that defines the containment relationship of the slice contours, and subsequently arranges the contours in an appropriate sequence, which facilitates toolpath planning for MMLM by avoiding redundant tool movements. The virtual simulation system simulates MMLM processes and provides stereoscopic visualisation of the resulting multi-material prototypes for quality analysis and optimisation of the processes.