383574
A simulation approach to verification and validation of formal specifications
Specification simulation is an approach to verifying and validating specifications by well-selected sample data. In this paper we put forward a technique for simulation of formal specifications in order to detect potential faults and validate their desired functions. The important benefit of this technique is it allows us to simulate implicit specifications, which are usually defined with a pair of pre- and postconditions and may not be executable. We discuss ways of simulation case generation, evaluation of logical expressions, and simulation result analysis, and demonstrate how they are applied in practice by examples.
18927685
Developing Quality Software Systems Using the SOFL Formal Engineering Method
Formal Engineering Methods are a bridge from Formal Methods to industrial applications. In this paper I describe the relation between formal engineering methods and formal methods, and present a specific formal engineering method SOFL (Structured Object-Oriented Formal Language) for developing quality software systems. I explain how SOFL can be applied in practice through examples.
11127695
The semantics of extended SOFL
SOFL (structured-object-based-formal language) has been extended to a formal object-oriented language and method while keeping its structured features. This extension allows powerful object-oriented reuse mechanisms, such as class inheritance and object composition, to be utilized in the early design phases. This paper presents the semantics for this extended SOFL, and further demonstrates the extendibility and reusability of the object-oriented semantic models of SOFL.
6161480
Homeostasis in a Silicon Integrate and Fire Neuron
In this work, we explore homeostasis in a silicon integrate-and-fire neuron. The neuron adapts its firing rate over long time periods on the order of seconds or minutes so that it returns to its spontaneous firing rate after a lasting perturbation. Homeostasis is implemented via two schemes. One scheme looks at the presynaptic activity and adapts the synaptic weight depending on the presynaptic spiking rate. The second scheme adapts the synaptic "threshold" depending on the neuron's activity. The threshold is lowered if the neuron's activity decreases over a long time and is increased for prolonged increase in postsynaptic activity. Both these mechanisms for adaptation use floating-gate technology. The results shown here are measured from a chip fabricated in a 2-µm CMOS process.
8457158
Spiking Inputs to a Winner-take-all Network
Recurrent networks that perform a winner-take-all computation have been studied extensively. Although some of these studies include spiking networks, they consider only analog input rates. We present results of this winner-take-all computation on a network of integrate-and-fire neurons which receives spike trains as inputs. We show how we can configure the connectivity in the network so that the winner is selected after a pre-determined number of input spikes. We discuss spiking inputs with both regular frequencies and Poisson-distributed rates. The robustness of the computation was tested by implementing the winner-take-all network on an analog VLSI array of 64 integrate-and-fire neurons which have an innate variance in their operating parameters.
227525
Integrated RFID data modeling: an approach for querying physical objects in pervasive computing
Radio frequency identiﬂcation(RFID) technology uses radio-frequency waves to transfer data between readers and mov-able tagged objects without line of sight. RFID holds thepromise of real-time identifying, locating, tracking and mon-itoring physical objects, and can be used for a wide range ofpervasive computing applications. To achieve these goals,RFID data have to be collected, transformed and expres-sively modeled as their virtual counterparts in the virtualworld. RFID data, however, have their own unique char-acteristics { including aggregation, location, temporal andhistory-oriented { which have to be fully considered and inte-grated into the data model. The diversity of RFID applica-tions pose further challenges to a generalized framework forRFID data modeling. In this paper, we explore the funda-mental characteristics of RFID data and classify RFID ap-plications into a set of typical scenarios. We then propose ageneralized RFID data modeling framework with constructsfor each typical scenario. These constructs can be combinedto model most RFID applications in real world.
11824549
An approach to detecting domain errors using formal specification-based testing
Domain testing, a technique for testing software or portions of software dominated by numerical processing, is intended to detect domain errors that usually arise from incorrect implementations of desired domains. This paper describes our recent work aiming to provide support for revealing domain errors using formal specifications. In our approach, formal specifications serve as a means for domain modeling. We describe a strong domain testing strategy that guide testers to select a set of test points so that the potential domain errors can be effectively detected, and apply our approach in two case studies for test cases generation.
18693305
Verifying Consistency and Validity of Formal Specifications by Testing
Detecting faults in specifications can help reduce the cost and risk of software development because incorrect implementation can be prevented early. This goal can be achieved by verifying the consistency and validity of specifications. In this paper we put forward specification testing as a practical technique for verification and validation of formal specifications. Our approach is to derive proof obligations from a specification and then test them, in order to detect faults leading to the violation of consistency or validity of the specification. We describe proof obligations for various consistency properties of a specification, and suggest the use of five strategies for testing them. We provide a method for testing implicit specifications by evaluation rather than by prototyping, and criteria for interpreting the meaning of test results.