70,033 research outputs found
Rule-Based Software Verification and Correction
The increasing complexity of software systems has led to the development of sophisticated formal Methodologies for verifying and correcting data and programs. In general, establishing whether a program behaves correctly w.r.t. the original programmer s intention or checking the consistency and the correctness of a large set of data are not trivial tasks as witnessed by many case studies which occur in the literature.
In this dissertation, we face two challenging problems of verification and correction. Specifically, verification and correction of declarative programs, and the verification and correction of Web sites (i.e. large collections of semistructured data).
Firstly, we propose a general correction scheme for automatically correcting declarative, rule-based programs which exploits a combination of bottom-up as well as topdown inductive learning techniques. Our hybrid hodology is able to infer program corrections that are hard, or even impossible, to obtain with a simpler,automatic top-down or bottom-up learner. Moreover, the scheme will be also particularized to some well-known declarative programming paradigm: that is, the functional logic and the functional programming paradigm.
Secondly, we formalize a framework for the automated verification of Web sites which can be used to specify integrity conditions for a given Web site, and then automatically check whether these conditions are fulfilled. We provide a rule-based, formal specification language which allows us to define syntactic as well as semantic
properties of the Web site. Then, we formalize a verification technique which detects both incorrect/forbidden patterns as well as lack of information, that is, incomplete/missing Web pages. Useful information is gathered during the verification process which can be used to repair the Web site. So, after a verification phase, one
can also infer semi-automatically some possible corrections in order to fix theWeb site.
The methodology is based on a novel rewritBallis, D. (2005). Rule-Based Software Verification and Correction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/194
Conceptual design and feasibility evaluation model of a 10 to the 8th power bit oligatomic mass memory. Volume 1: Conceptual design
The oligatomic (mirror) thin film memory technology is a suitable candidate for general purpose spaceborne applications in the post-1975 time frame. Capacities of around 10 to the 8th power bits can be reliably implemented with systems designed around a 335 million bit module. The recommended mode was determined following an investigation of implementation sizes ranging from an 8,000,000 to 100,000,000 bits per module. Cost, power, weight, volume, reliability, maintainability and speed were investigated. The memory includes random access, NDRO, SEC-DED, nonvolatility, and dual interface characteristics. The applications most suitable for the technology are those involving a large capacity with high speed (no latency), nonvolatility, and random accessing
Understanding Evolutionary Potential in Virtual CPU Instruction Set Architectures
We investigate fundamental decisions in the design of instruction set
architectures for linear genetic programs that are used as both model systems
in evolutionary biology and underlying solution representations in evolutionary
computation. We subjected digital organisms with each tested architecture to
seven different computational environments designed to present a range of
evolutionary challenges. Our goal was to engineer a general purpose
architecture that would be effective under a broad range of evolutionary
conditions. We evaluated six different types of architectural features for the
virtual CPUs: (1) genetic flexibility: we allowed digital organisms to more
precisely modify the function of genetic instructions, (2) memory: we provided
an increased number of registers in the virtual CPUs, (3) decoupled sensors and
actuators: we separated input and output operations to enable greater control
over data flow. We also tested a variety of methods to regulate expression: (4)
explicit labels that allow programs to dynamically refer to specific genome
positions, (5) position-relative search instructions, and (6) multiple new flow
control instructions, including conditionals and jumps. Each of these features
also adds complication to the instruction set and risks slowing evolution due
to epistatic interactions. Two features (multiple argument specification and
separated I/O) demonstrated substantial improvements int the majority of test
environments. Some of the remaining tested modifications were detrimental,
thought most exhibit no systematic effects on evolutionary potential,
highlighting the robustness of digital evolution. Combined, these observations
enhance our understanding of how instruction architecture impacts evolutionary
potential, enabling the creation of architectures that support more rapid
evolution of complex solutions to a broad range of challenges
A study of mission duration extension problems Summary report, 1 Oct. 1966 - 1 Oct. 1967
Characteristics, constraints, and implications of long duration space missions based on use of available hardware and maintenance/repair actions in spac
Multi-man flight simulator
A prototype Air Traffic Control facility and multiman flight simulator facility was designed and one of the component simulators fabricated as a proof of concept. The facility was designed to provide a number of independent simple simulator cabs that would have the capability of some local, stand alone processing that would in turn interface with a larger host computer. The system can accommodate up to eight flight simulators (commercially available instrument trainers) which could be operated stand alone if no graphics were required or could operate in a common simulated airspace if connected to the host computer. A proposed addition to the original design is the capability of inputing pilot inputs and quantities displayed on the flight and navigation instruments to the microcomputer when the simulator operates in the stand alone mode to allow independent use of these commercially available instrument trainers for research. The conceptual design of the system and progress made to date on its implementation are described
Quantitative Robustness Analysis of Quantum Programs (Extended Version)
Quantum computation is a topic of significant recent interest, with practical
advances coming from both research and industry. A major challenge in quantum
programming is dealing with errors (quantum noise) during execution. Because
quantum resources (e.g., qubits) are scarce, classical error correction
techniques applied at the level of the architecture are currently
cost-prohibitive. But while this reality means that quantum programs are almost
certain to have errors, there as yet exists no principled means to reason about
erroneous behavior. This paper attempts to fill this gap by developing a
semantics for erroneous quantum while-programs, as well as a logic for
reasoning about them. This logic permits proving a property we have identified,
called -robustness, which characterizes possible "distance" between
an ideal program and an erroneous one. We have proved the logic sound, and
showed its utility on several case studies, notably: (1) analyzing the
robustness of noisy versions of the quantum Bernoulli factory (QBF) and quantum
walk (QW); (2) demonstrating the (in)effectiveness of different error
correction schemes on single-qubit errors; and (3) analyzing the robustness of
a fault-tolerant version of QBF.Comment: 34 pages, LaTeX; v2: fixed typo
Introduction to linear logic and ludics, part II
This paper is the second part of an introduction to linear logic and ludics,
both due to Girard. It is devoted to proof nets, in the limited, yet central,
framework of multiplicative linear logic and to ludics, which has been recently
developped in an aim of further unveiling the fundamental interactive nature of
computation and logic. We hope to offer a few computer science insights into
this new theory
Automated Synthesis of SEU Tolerant Architectures from OO Descriptions
SEU faults are a well-known problem in aerospace environment but recently their relevance grew up also at ground level in commodity applications coupled, in this frame, with strong economic constraints in terms of costs reduction. On the other hand, latest hardware description languages and synthesis tools allow reducing the boundary between software and hardware domains making the high-level descriptions of hardware components very similar to software programs. Moving from these considerations, the present paper analyses the possibility of reusing Software Implemented Hardware Fault Tolerance (SIHFT) techniques, typically exploited in micro-processor based systems, to design SEU tolerant architectures. The main characteristics of SIHFT techniques have been examined as well as how they have to be modified to be compatible with the synthesis flow. A complete environment is provided to automate the design instrumentation using the proposed techniques, and to perform fault injection experiments both at behavioural and gate level. Preliminary results presented in this paper show the effectiveness of the approach in terms of reliability improvement and reduced design effort
Functional design for operational earth resources ground data processing
The author has identified the following significant results. Study emphasis was on developing a unified concept for the required ground system, capable of handling data from all viable acquisition platforms and sensor groupings envisaged as supporting operational earth survey programs. The platforms considered include both manned and unmanned spacecraft in near earth orbit, and continued use of low and high altitude aircraft. The sensor systems include both imaging and nonimaging devices, operated both passively and actively, from the ultraviolet to the microwave regions of the electromagnetic spectrum
Techniques for the realization of ultrareliable spaceborne computers Interim scientific report
Error-free ultrareliable spaceborne computer
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