7160160
QoS-UniFrame: a Petri net-based modeling approach to assure QoS requirements of distributed real-time and embedded systems
Assuring quality of service (QoS) requirements is critical when assembling a distributed real-time and embedded (DRE) system from a repository of existing components. This paper presents a two-level approach for assuring satisfaction of QoS requirements in the context of a reduced design space for DRE systems. A dynamic and parallel approach is introduced to prune off the infeasible design spaces at the first level. Evolutionary algorithms cooperating with a domain-specific scripting language then discard less probable design spaces using statistics. These techniques fulfill the collective objectives of pruning and assuring the design space at system assembly time.
15212910
A software product line architecture for distributed real-time and embedded systems: a separation of concerns approach
This paper presents a separation of concerns approach to solve the tangling problem of functional and Quality of Service (QoS) concerns in traditional Component-based Software Engineering (CBSE) and Software Product Line (SPL) technologies applied to Distributed Real-time and Embedded (DRE) systems. This problem originates from the interchangeability for fulfilling functional and QoS concerns during composition. The approach utilizes the perspective of QoS to design and analyze a set of software systems represented by a collection of QoS systemic paths, which determine how well functional tasks perform in terms of flows of application-specific and functionality-determined information between components. Our approach not only reserves the virtues of reusability, changeability, productivity and expeditiousness that traditional CBSE and SPL technologies possess, but also dedicates the contributions in terms of separation of concerns, design space exploration, fine-grained commonality and reusability evaluation and less subjective feasibility analyses for a component-based SPL.
9506912
Quantifying Input and Output Spike Statistics of a Winner-Take-All Network in a Vision System
Event-driven spike-based processing systems offer new possibilities for real-time vision. Signals are encoded asynchronously in time thus preserving the time information of the occurrence of an event. The paper examines this form of coding using experimental data from a multi-layered multi-chip system which consists of an artificial retina, a convolution filter bank and a winner-take-all network which detect the position of a moving object. The spike outputs of the convolution stage can be described by an inhomogeneous Poisson distribution of Gaussian profile, although the underlying building blocks are completely deterministic and exhibit only a small amount of variation. The authors discuss a method for measuring the accuracy of the asynchronous spiking representation in both time and value, thereby quantifying the performance of the winner-take-all network in determining the position of a ball rotating in front of the system.
14515232
An investigation of the approach to specification-based program review through case studies
Software review is an effective means to enhance the quality of software systems. However, traditional review methods emphasize the importance of the way to organize reviews and rely on the quality of the reviewers' experience and personal skills. In this paper we propose a new approach to rigorously reviewing programs based on their formal specifications. The fundamental idea of the approach is to use a formal specification as a standard to check whether all the required functions and properties in the specification are correctly implemented by its program. To help investigate the effectiveness and the weakness of the approach, we conduct two case studies of reviewing two program systems that implement the same formal specification of "A Research Management Policy" using different strategies, and present the evaluation of the case studies. The results show that the review approach is effective in detecting faults when the reviewer is different from the programmer, but less effective when the reviewer is the same as the programmer.
6009818
A Formal Definition of FRSM and Applications
FRSM (Formal Requirements Specification Method) is a structured formal language and method for requirements analysis and specification construction based on data flow analysis. It uses a formalized DeMarco data flow diagram to describe the overall structure of systems and a VDM-SL like formal notation to describe precisely the functionality of components in the diagrams. This paper first describes the formal syntax and semantics of FRSM and then presents an example of using the axiom and inference rules given in the definition of the formal semantics for checking consistency of specifications. A case study of applying FRSM to a practical example is described to demonstrate the principle of constructing requirements specifications and to uncover the benefits and deficiencies of FRSM.
1275297
Bridging Physical and Virtual Worlds: Complex Event Processing for RFID Data Streams
Advances of sensor and RFID technology provide significant new power for humans to sense, understand and manage the world. RFID provides fast data collection with precise identification of objects with unique IDs without line of sight, thus it can be used for identifying, locating, tracking and monitoring physical objects. Despite these benefits, RFID poses many challenges for data processing and management: i) RFID observations contain duplicates, which have to be filtered; ii) RFID observations have implicit meanings, which have to be transformed and aggregated into semantic data represented in their data models; and iii) RFID data are temporal, streaming, and in high volume, and have to be processed on the fly. Thus, a general RFID data processing framework is needed to automate the transformation of physical RFID observations into the virtual counterparts in the virtual world linked to business applications. In this paper, we take an event-oriented approach to process RFID data, by devising RFID application logic into complex events. We then formalize the specification and semantics of RFID events and rules. We demonstrate that traditional ECA event engine cannot be used to support highly temporally constrained RFID events, and develop an RFID event detection engine that can effectively process complex RFID events. The declarative event-based approach greatly simplifies the work of RFID data processing, and significantly reduces the cost of RFID data integration.
16061427
A wide-field direction-selective aVLSI spiking neuron
We describe an analog Very-Large-Scale Integrated (aVLSI) wide-field direction-selective spiking neuron that responds robustly to both natural and artificial images. The circuitry is based on a model of the wide-field direction-selective neurons in the fly visual system. The architecture of the chip closely follows the anatomical layout of the fly visual system. The circuit has a one-dimensional array of 37 elementary motion detectors (EMDs); each of which provides local motion information to the wide-field spiking neuron. Normalisation and adaptation are employed in the circuits at each processing stage. The inputs to the EMDs saturate with high contrasts so that the motion output is not confounded with the signal contrast. The outputs of the EMDs are aggregated in a nonlinear way to produce a motion output that is independent of the stimulus size. The global aggregated signal is then used to drive an integrate-and-fire neuron. All the computation is analog except for the output of the spiking neuron. We show results from the fabricated circuit.