| 1. |
- Pozzer, Cesar, et al.
(författare)
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Imprecise Computation as an Enabler for Complex and Time Critical HLA Simulation Networks
- 2014
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Ingår i: Proceedings of Simulation Interoperability Workshop. - 9781634393898 ; , s. 171-179
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Konferensbidrag (refereegranskat)abstract
- A trend over the past years is that simulation systems for training are being connected in simulation networks, allowing the interaction of teams spread in distributed sites. By combining interconnected simulation systems the simulation complexity increases and may affect time-critical simulation tasks in a negative way. As a consequence, the training simulation objectives may not be met. The same problem may occur when performing, for example, mission rehearsal on site, since available computation resources are usually very limited in this scenario, or for a joint fires scenario, where the large and complex functional chain (including intelligence, C2, forward observer, pilots, etc.) may overload existing resources. In this work, the technique of imprecise computation in real-time systems (ICRS) to preserve time-critical simulation tasks is presented. The ICRS technique allows time-critical tasks to produce quicker solutions for approximate results and saves computational resources. This paper discusses the main advantages of theICRS technique by a review of the commonly used optimization concepts built upon imprecise computation field. Thepaper ends with presenting a work-in-progress: an architectural solution for aligning ICRS with the High Level Architecture (HLA), standardized as the IEEE 1516-series.
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| 2. |
- Bae, Juhee, et al.
(författare)
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Complex Data Analysis
- 2019
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Ingår i: Data science in Practice. - Cham : Springer. - 9783319975566 - 9783319975559 ; , s. 157-169
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Bokkapitel (refereegranskat)abstract
- Data science applications often need to deal with data that does not fit into the standard entity-attribute-value model. In this chapter we discuss three of these other types of data. We discuss texts, images and graphs. The importance of social media is one of the reason for the interest on graphs as they are a way to represent social networks and, in general, any type of interaction between people. In this chapter we present examples of tools that can be used to extract information and, thus, analyze these three types of data. In particular, we discuss topic modeling using a hierarchical statistical model as a way to extract relevant topics from texts, image analysis using convolutional neural networks, and measures and visual methods to summarize information from graphs.
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| 3. |
- Berndtsson, Mikael, et al.
(författare)
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Visualization of the Composite Event Detection Process
- 1999
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Ingår i: Proceedings User Interfaces to Data Intensive Systems. - 0769502628 - 0769502644 ; , s. 118-127
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Konferensbidrag (refereegranskat)abstract
- Active database rules are problematic to explain, understand, debug, and design irrespective of knowledge about active rule semantics. In order to address this problem, various types of active database tools have been proposed in the literature such as browsers, debuggers, analyzers, and explanation tools.This paper focuses on visualization of event detection for an explanation tool and it presents the first study on what to visualize with respect to event detection at the lowest level (i.e. visualization of event detection for a specific event type).
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| 4. |
- Mellin, Jonas, 1965-
(författare)
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Resource-Predictable and Efficient Monitoring of Events
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We present a formally specified event specification language (Solicitor). Solicitor is suitable for real-time systems, since it results in resource-predictable and efficient event monitors. In event monitoring, event expressions defined in an event specification language control the monitoring by matching incoming streams of event occurrences against the event expressions. When an event expression has a complete set of matching event occurrences, the event type that this expression defines has occurred. Each event expression is specified by combining contributing event types with event operators such as sequence, conjunction, disjunction; contributing event types may be primitive, representing happenings of interest in a system, or composite, specified by event expressions.The formal specification of Solicitor is based on a formal schema that separates two important aspects of an event expression; these aspects are event operators and event contexts. The event operators aspect addresses the relative constraints between contributing event occurrences, whereas the event contexts aspect addresses the selection of event occurrences from an event stream with respect to event occurrences that are used or invalidated during event monitoring. The formal schema also contains an abstract model of event monitoring. Given this formal specification, we present realization issues of, a time complexity study of, as well as a proof of limited resource requirements of event monitoring.We propose an architecture for resource-predictable and efficient event monitoring. In particular, this architecture meets the requirements of realtime systems by defining how event monitoring and tasks are associated. A declarative way of specifying this association is proposed within our architecture. Moreover, an efficient memory management scheme for event composition is presented. This scheme meets the requirements of event monitoring in distributed systems. This architecture has been validated by implementing an executable component prototype that is part of the DeeDS prototype.The results of the time complexity study are validated by experiments. Our experiments corroborate the theory in terms of complexity classes of event composition in different event contexts. However, the experimental platform is not representative of operational real-time systems and, thus, the constants derived from our experiments cannot be used for such systems.
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| 5. |
- Mellin, Jonas, et al.
(författare)
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Using Imprecise Computation for Virtual and Constructive Simulations
- 2014
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Ingår i: Proceedings of the 2014 Winter Simulation Conference. - : IEEE Press. - 9781479974863 ; , s. 4043-4044
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Konferensbidrag (refereegranskat)abstract
- In this work, we raise three critical questions that must be investigated to ameliorate composability ofvirtual simulation models and to enable adoption of systematic and stringent real-time techniques toenable more scalable simulation models for virtual and constructive simulation. The real-time techniquesin question enable us to separate between policies and mechanisms and, thus, the simulation engine candecide dynamically how to run the simulation given the existing resources (e.g., processor) and the goalsof the simulation (e.g., sufficient fidelity in terms of timing and accuracy). The three critical questionsare: (i) how to design efficient and effective algorithms for making dynamic simulation model designdecisions during simulation; (ii) how to map simulation entities (e.g., agents) into (real-time) tasks; and(iii) how to enable a divide and conquer approach to validating simulation models.
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