Procurement and Initial Characterization of Alloy 230 and CMS Alloy 617

Material for initial testing of alloy 230 and a controlled-chemistry variant of alloy 617 has been procured in the form of plates. ¾-inch thick alloy 230 plate was commercially procured from Haynes International, and 2-inch thick CCA 617, an existing controlled-chemistry variant of alloy 617, was obtained from Alstom Power through the ultra-supercritical fossil energy program. This report describes the procurement of these plates and their characteristics in terms of vendor-supplied chemistry and mechanical properties. Further detailed characterization tests are planned for this fiscal year, and this report will be updated in September 2006 to include the results of these tests

UTP, Circus, and Isabelle

We dedicate this paper with great respect and friendship to He Jifeng on the occasion of his 80th birthday. Our research group owes much to him. The authors have over 150 publications on unifying theories of programming (UTP), a research topic Jifeng created with Tony Hoare. Our objective is to recount the history of Circus (a combination of Z, CSP, Dijkstra’s guarded command language, and Morgan’s refinement calculus) and the development of Isabelle/UTP. Our paper is in two parts. (1) We first discuss the activities needed to model systems: we need to formalise data models and their behaviours. We survey our work on these two aspects in the context of Circus. (2) Secondly, we describe our practical implementation of UTP in Isabelle/HOL. Mechanising UTP theories is the basis of novel verification tools. We also discuss ongoing and future work related to (1) and (2). Many colleagues have contributed to these works, and we acknowledge their support

Reducing structural ambiguity in natural language software requirements specifications

Abstract. The ambiguity of natural language (NL) causes miscommunication and misunderstandings. Precision of language is particularly important in software development when handling requirements agreed between the customer and the provider. Software Requirements Specification (SRS) is a commonly used document type for specifying the requirements. A strict standard for how every SRS should be constructed does not exist, and thus it is often written in NL. However, some restricted languages can be used for specifying requirements. An example of such is Easy Approach to Requirements Syntax (EARS). In this thesis is presented an automated tool for reducing the structural ambiguity of requirements by converting NL into EARS form. Four different text datasets were used for testing the converter and they were compared before and after conversion and against each other. Both performance and ambiguity reduction of the tool were assessed using various measures. Since a standard ambiguity measurement was not available, a combination of sentence structure assessment, word occurrences against Zipf’s law, readability score and information complexity was used. The results suggest that the tool reduces structural ambiguity of sentences. The tool is successful in converting NL into the different EARS patterns and the converted sentences are less complicated and more readable, according to the results. This hints at the possibility of creating more automated tools that could be used to reduce ambiguity in NL SRS. It might not be possible to make people start using a restricted language, like EARS, for writing the documents, but with the help of automated converters, sentences could be mapped to more restricted forms to help with making better sense of them.Luonnollisen kielen rakenteellisen moniselitteisyyden vähentäminen ohjelmistojen vaatimusten määrittelyissä. Tiivistelmä. Luonnollisen kielen epämääräisyys aiheuttaa vaikeuksia kommunikoinnissa ja ymmärtämisessä. Kielen tarkkuus on erityisen tärkeää ohjelmistokehityksessä silloin kun käsitellään asiakkaan ja tarjoajan keskenään sopimia vaatimuksia ohjelmistolle. Ei ole olemassa tiukkaa standardia sille miten vaatimusten määrittelydokumentti pitäisi rakentaa, joten se usein kirjoitetaan luonnollisella kielellä. Siitä huolimatta joitain rajoitettuja kieliä voidaan käyttää yksittäisten vaatimusten määrittelyyn. Eräs esimerkki rajoitetusta kielestä on Easy Approach to Requirements Syntax (EARS). Tässä diplomityössä esitellään automatisoitu työkalu vähentämään rakenteista epämääräisyttä muuttamalla luonnollista kieltä EARS-muotoon. Neljää erilaista tekstiä käytettiin työkalun testaamiseen ja niitä verrattiin toisiinsa sekä ennen että jälkeen muuntamisen. Työkalun toimintaa ja epämääräisyyden vähentämistä mitattiin useilla metriikoilla. Epämääräisyyden mittaamiseen valittiin joukko kvantitatiivisia metriikoita: lauserakenteita analysoitiin, sanojen ilmiintyvyystiheyttä ja lausiden luettavuutta mitattiin ja informaation kompleksisuuttakin verrattiin muunnettujen ja muuntamattomien tekstien välillä. Tulosten perusteella esitelty työkalu vähentää lauseiden rakenteellista epämääräisyyttä. Se muuntaa onnistuneesti luonnollista kieltä EARS-muotoon ja tulosten mukaan muunnetut lauseet ovat vähemmän monimutkaisia ja luettavampia. Tämä viittaa siihen, että automatisoiduilla työkaluilla voisi olla mahdollista vähentää epämääräisyyttä luonnollisella kielellä kirjoitetuissa vaatimusten määrittelydokumenteissa. Vaikkei ihmisiä saataisikaan kirjoittamaan vaatimusten määrittelyjä rajoitetuilla kielillä, automatisoiduilla kielen muuntajilla lauseita voidaan uudelleenmuotoilla rajoitetumpiin muotoihin, jotta niistä saataisiin paremmin selvää

Independent Orbiter Assessment (IOA): FMEA/CIL assessment

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. Direction was given by the Orbiter and GFE Projects Office to perform the hardware analysis and assessment using the instructions and ground rules defined in NSTS 22206. The IOA analysis features a top-down approach to determine hardware failure modes, criticality, and potential critical items. To preserve independence, the anlaysis was accomplished without reliance upon the results contained within the NASA and prime contractor FMEA/CIL documentation. The assessment process compares the independently derived failure modes and criticality assignments to the proposed NASA Post 51-L FMEA/CIL documentation. When possible, assessment issues are discussed and resolved with the NASA subsystem managers. The assessment results for each subsystem are summarized. The most important Orbiter assessment finding was the previously unknown stuck autopilot push-button criticality 1/1 failure mode, having a worst case effect of loss of crew/vehicle when a microwave landing system is not active

The small community solar thermal power experiment. Parabolic dish technology for industrial process heat application

Aspects of incorporating a thermal energy transport system (ETS) into a field of parabolic dish collectors for industrial process heat (IPH) applications were investigated. Specific objectives are to: (1) verify the mathematical optimization of pipe diameters and insulation thicknesses calculated by a computer code; (2) verify the cost model for pipe network costs using conventional pipe network construction; (3) develop a design and the associated production costs for incorporating risers and downcomers on a low cost concentrator (LCC); (4) investigate the cost reduction of using unconventional pipe construction technology. The pipe network design and costs for a particular IPH application, specifically solar thermally enhanced oil recovery (STEOR) are analyzed. The application involves the hybrid operation of a solar powered steam generator in conjunction with a steam generator using fossil fuels to generate STEOR steam for wells. It is concluded that the STEOR application provides a baseline pipe network geometry used for optimization studies of pipe diameter and insulation thickness, and for development of comparative cost data, and operating parameters for the design of riser/downcomer modifications to the low cost concentrator

Architectural Refinement in HETS

The main objective of this work is to bring a number of improvements to the Heterogeneous Tool Set HETS, both from a theoretical and an implementation point of view. In the first part of the thesis we present a number of recent extensions of the tool, among which declarative specifications of logics, generalized theoroidal comorphisms, heterogeneous colimits and integration of the logic of the term rewriting system Maude. In the second part we concentrate on the CASL architectural refinement language, that we equip with a notion of refinement tree and with calculi for checking correctness and consistency of refinements. Soundness and completeness of these calculi is also investigated. Finally, we present the integration of the VSE refinement method in HETS as an institution comorphism. Thus, the proof manangement component of HETS remains unmodified

Independent Orbiter Assessment (IOA): CIL issues resolution report, volume 1

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. This report contains IOA assessment worksheets showing resolution of outstanding IOA CIL issues that were summarized in the IOA FMEA/CIL Assessment Interim Report, dated 9 March 1988. Each assessment worksheet has been updated with CIL issue resolution and rationale. The NASA and Prime Contractor post 51-L FMEA/CIL documentation assessed is believed to be technically accurate and complete. No assessment issues remain that has safety implications. Volume 1 contain worksheets for the following sybsystems: Landing and Deceleration Subsystem; Purge, Vent and Drain Subsystem; Active Thermal Control and Life Support Systems; Crew Equipment Subsystem; Instrumentation Subsystem; Data Processing Subsystem; Atmospheric Revitalization Pressure Control Subsystem; Hydraulics and Water Spray Boiler Subsystem; and Mechanical Actuation Subsystem