Towards more accurate real time testing

The languages Message Sequence Charts (MSC) [1], System Design Language1 (SDL) [2] and Testing and Test Control Notation Testing2 (TTCN-3) [3] have been developed for the design, modelling and testing of complex software systems. These languages have been developed to complement one another in the software development process. Each of these languages has features for describing, analysing or testing the real time properties of systems. Robust toolsets exist which provide integrated environments for the design, analysis and testing of systems, and it is claimed, for the complete development of real time systems. It was shown in [4] however, that there are fundamental problems with the SDL language and its associated tools for modelling and reasoning about real time systems. In this paper we present the limitations of TTCN-3 and propose recommendations which help minimise the timing inaccuracies that would otherwise occur in using the language directly

On the applicability of empirical heat transfer models for hydrogen combustion engines

Hydrogen-fuelled internal combustion engines are being investigated as an alternative for current drive trains because they have a high efficiency, near-zero noxious and zero tailpipe greenhouse gas emissions. A thermodynamic model of the engine cycle would enable a cheap and fast optimization of engine settings for operation on hydrogen, facilitating the development of these engines. The accuracy of the heat transfer submodel within the thermodynamic model is important to simulate accurately the emissions of oxides of nitrogen which are influenced by the maximum gas temperature. These emissions can occur in hydrogen internal combustion engines at high loads and they are an important constraint for power and efficiency optimization. The most common heat transfer models in engine research are those from Annand and Woschni. These models are developed for fossil fuels, which have different combustion properties. Therefore, they need to be evaluated for hydrogen. We have measured the heat flux and the wall temperature in an engine that can run on hydrogen and methane. This paper describes an evaluation of the models of Annand and Woschni, using those heat flux measurements and assesses if the models capture the effect of changing combustion and fuel properties. The models fail on all the tests, so they need to be improved to accurately model the heat transfer generated by hydrogen combustion

Bubble memory module

Design, fabrication and test of partially populated prototype recorder using 100 kilobit serial chips is described. Electrical interface, operating modes, and mechanical design of several module configurations are discussed. Fabrication and test of the module demonstrated the practicality of multiplexing resulting in lower power, weight, and volume. This effort resulted in the completion of a module consisting of a fully engineered printed circuit storage board populated with 5 of 8 possible cells and a wire wrapped electronics board. Interface of the module is 16 bits parallel at a maximum of 1.33 megabits per second data rate on either of two interface buses

Engine Fuel Injection Timing : A Design for an Automatic Verification System

This thesis describes the development of an automatic testing system for the timing of the fuel injection of a 4-stroke engine. The fuel injection timing is managed by an electronic engine control unit which has a distributed modular design. New software and hardware updates are released every few months for the engine control unit. Furthermore, fuel injection timing must be tested for each new software release, because incorrect timing could potentially lead to engine failure. Thus, automating this frequent testing procedure, which can take 2–5 days manually, is expected to save both time and money. Therefore, the object of this work is to develop a design of an automatic fuel injection timing testing system. There are already abundant scientific studies available related to fuel injection timing and engine control unit. The majority of these studies in the literature review cover various topics about the effects of alternative injection technologies and fuels. A limited number of them comprise the subject of automatic fuel injection timing. Design science was chosen as the research method because of its suitability for product development projects. The most important research question is what the design architecture must be like for testing injection timing. This work started with a comprehensive analysis of the different factors that could affect the design. Underlying motivation for developing an automatic testing system, stakeholders involved, alternative ways for testing implementation, and various other points of view were covered. After defining the system requirements, the setup was built to measure the timing of fuel injection pulses from the engine control unit, which utilized the National Instruments Compact RIO hardware and software programmed with LabVIEW. This program automatically generates an Excel report of the timing test. The design of a testing system architecture that would allow measurements to be made from any of the 112 fuel injection terminals of the control unit was successfully developed. Measurements performed with Compact RIO hardware proved to be accurate and could determine the crankshaft angle with the required accuracy. The accuracy of the testing system was ±5 μs. Next, the development of communication between the testing hardware and the engine control unit’s configuration software was identified as the most important issue for future development of the testing system. The proposed testing system principle is probably feasible for developing any further automatic testing systems for any electric engine control unit in which fuel injection timing needs to be verified. Moreover, Compact RIO hardware and LabVIEW software can be recommended as a tool for developing similar verification systems because they are relatively easy to use, flexible, reliable, and capable of high-speed measurements.Tämä diplomityö kuvaa automaattisen testausjärjestelmän kehittämistä nelitahtimoottorin polttoaineen ruiskutussignaalien ajoitukselle. Ruiskutuksen ajoitusta hallitaan sähköisellä moottorinohjausyksiköllä, millä on hajautettu modulaarinen rakenne. Uusia moottorinohjausyksikön ohjelmisto- ja laitteistoversioita julkaistaan muutaman kuukauden välein. Polttoaineensyötön oikea ajoitus täytyy testata aina, kun uusia versioita julkaistaan, koska väärä ajoitus saattaa aiheuttaa moottorihäiriön. Usein toistuvan testauksen automatisoinnin odotetaan lyhentävän siihen käytettävää aikaa ja kustannuksia merkittävästi, mikä manuaalisesti tehtynä voi kestää 2–5 päivää. Työn tavoitteena on kehittää suunnitelma automaattisesta testausjärjestelmästä polttoaineen ruiskutuksen ajoitukselle. Polttoaineenruiskutukseen ja moottorinohjausyksiköihin liittyviä tieteellisiä julkaisuja on saatavilla runsaasti. Suurin osa kirjallisuuskatsauksessa käsitellyistä tutkimuksista kattaa eri aiheita vaihtoehtoisten ruiskutustekniikoiden ja polttoaineiden vaikutuksista polttomoottoriin. Vain muutama niistä käsittelee polttoaineensyötön automaattista testausta. Tutkimusmenetelmäksi valittiin suunnittelutiede, koska se soveltuu hyvin tuotekehitysprojekteihin. Tärkein tutkimuskysymys on: ”Minkälainen järjestelmän arkkitehtuurin täytyy olla ruiskutuksen ajoituksen testaamista varten?” Kysymyksen tutkiminen aloitettiin analysoimalla perusteellisesti eri tekijöitä, jotka voisivat vaikuttaa toteutukseen. Mikä on se perimmäinen syy miksi automaattinen testausjärjestelmä halutaan kehittää, mukana olevat sidosryhmät, vaihtoehtoiset toteutustavat sekä useita muita näkökulmia huomioitiin. Järjestelmävaatimusten määrittelyn jälkeen rakennettiin koelaite, jolla mitattiin polttoaineensyötön pulssien ajoitusta moottorinohjausyksiköstä, mikä hyödynsi National Instruments Compact RIO laitteistoa ja ohjelmistoa mikä kehitettiin LabVIEW -kehitysympäristössä. Ohjelma luo automaattisesti Excel raportin ajoitustesteistä. Onnistuneesti luotiin testausjärjestelmän arkkitehtuuri, mikä mahdollistaa mittausten tekemisen mistä tahansa hajautetun moottorinohjausyksikön 112 polttoaineensyötön liittimestä. Compact RIO laitteistolla tehdyt mittaukset osoittautuivat tarkoiksi ja se pystyy määrittämään kampiakselin kulman vaaditulla tarkkuudella. Testausjärjestelmän tarkkuus oli ±5 μs. Kommunikaation kehittäminen testauslaitteiston ja moottorinohjausyksikön konfigurointi ohjelmiston välille tunnistettiin kaikkein tärkeimmäksi asiaksi testausjärjestelmän jatkokehitykselle. Ehdotettu arkkitehtuuri on todennäköisesti sopiva ratkaisu automaattisen testausjärjestelmän kehittämiseksi mille tahansa sähköiselle moottorinohjausyksikölle, jonka polttoaineen ruiskutuksen ajoitus halutaan varmentaa. Lisäksi Compact RIO laitteistoa ja LabVIEW ohjelmistoa voidaan suositella työkaluiksi vastaavien testausjärjestelmien kehittämiseen koska ne ovat kohtuullisen helppokäyttöisiä, joustavia, luotettavia ja pystyvät nopeisiin mittauksiin

Software engineering: Testing real-time embedded systems using timed automata based approaches

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Real-time Embedded Systems (RTESs) have an increasing role in controlling society infrastructures that we use on a day-to-day basis. RTES behaviour is not based solely on the interactions it might have with its surrounding environment, but also on the timing requirements it induces. As a result, ensuring that an RTES behaves correctly is non-trivial, especially after adding time as a new dimension to the complexity of the testing process. This research addresses the problem of testing RTESs from Timed Automata (TA) specification by the following. First, a new Priority-based Approach (PA) for testing RTES modelled formally as UPPAAL timed automata (TA variant) is introduced. Test cases generated according to a proposed timed adequacy criterion (clock region coverage) are divided into three sets of priorities, namely boundary, out-boundary and in-boundary. The selection of which set is most appropriate for a System Under Test (SUT) can be decided by the tester according to the system type, time specified for the testing process and its budget. Second, PA is validated in comparison with four well-known timed testing approaches based on TA using Specification Mutation Analysis (SMA). To enable the validation, a set of timed and functional mutation operators based on TA is introduced. Three case studies are used to run SMA. The effectiveness of timed testing approaches are determined and contrasted according to the mutation score which shows that our PA achieves high mutation adequacy score compared with others. Third, to enhance the applicability of PA, a new testing tool (GeTeX) that deploys PA is introduced. In its current version, GeTeX supports Control Area Network (CAN) applications. GeTeX is validated by developing a prototype for that purpose. Using GeTeX, PA is also empirically validated in comparison with some TA testing approaches using a complete industrial-strength test bed. The assessment is based on fault coverage, structural coverage, the length of generated test cases and a proposed assessment factor. The assessment is based on fault coverage, structural coverage, the length of generated test cases and a proposed assessment factor. The assessment results confirmed the superiority of PA over the other test approaches. The overall assessment factor showed that structural and fault coverage scores of PA with respect to the length of its tests were better than the others proving the applicability of PA. Finally, an Analytical Hierarchy Process (AHP) decision-making framework for our PA is developed. The framework can provide testers with a systematic approach by which they can prioritise the available PA test sets that best fulfils their testing requirements. The AHP framework developed is based on the data collected heuristically from the test bed and data collected by interviewing testing experts. The framework is then validated using two testing scenarios. The decision outcomes of the AHP framework were significantly correlated to those of testing experts which demonstrated the soundness and validity of the framework.This study is funded by Damascus University, Syri

Modelling of Bulk Material Flow Properties

Flow property testing is important in the design of handling equipment for bulk solids and the Jenike shear tester is a common and reliable method for ensuring flow from hoppers under the force of gravity alone. The Jenike shear test procedure has various stages and is known to have issues with operator dependency, questions have also been raised regarding the stress state within the shear cell. Currently the data for high pressure flow functions, which are applicable to large capacity storage facilities, are extrapolated from low pressure test data using a 3-parameter equation. Very little literature is provided to support the use of the 3-parameter equation and most shear testing devices are limited to major consolidation stresses of 100 kPa

SCALED DYNAMIC TESTING ON LIGHTWEIGHT CONCRETE FOR WAVE SUPPRESSING SYSTEM

The Wave Suppression System (WSS) invented by Mohammad Firdaus Hashim has shown promising results, and UTP is keen to further develop the invention to the point of making it commercially usable and viable. 'This project serves as part of UTP 's effort to make the WSS workable, viable and durable for commercial use. The project focuses on trying to determine the durability of the ALC used in the WSS by conducting a series of tests which best simulates the dynamic wave forces to a scaled model. There will be two main test; maximum strength and cyclic loading resistance. The former results are significant in two ways; they provide a reference load to the second tests and providing maximum strength value for WSS designers to relate with the retnrn period of certain wave heights. The return period of a wave height that is equal to the WSS maximum strength shall serve as the lifespan of the WSS in terms of years. If the maximum strength is equivalent to a 10 m wave height, and the targeted coast area has a hypothetical 20 years return period for I 0 m waves, the WSS will theoretically last for 20 years. However, even low wave heights, which equal low forces, which continuously hit the WSS of long period of time may cause the WSS to fail due to fatigue crack propagation. This is why the second test is employed to determine its resistance for cyclic loading. The test will give the maximum number of cycles the WSS can withstand before failure at a variety of frequencies arbitrarily set to the most common wave periods. The load shall be varied in terms of percentage of the maximum load. It must be noted that in order to compare the results with the aetna! wave forces, dynamic similarity must be achieved as close as possible between the intended full scale prototype and the scaled model. The dynamic similarity is reasonably achievedby correcting the results with the appropriate scale factor. The corrected results will then be used as a basis for comparison with actual wave periods. The experiments results expose the ALC weakness, which is low maximum strength and low resistance to cyclic loading. Even under the most favourable coastal circumstances the ALC will struggle to last for more than 6 months

An Experimental Study of a Pulsed DC Plasma Flow Control Actuator

An experiment on the effects of a pulsed DC plasma actuator on a separated flow in a low speed wind tunnel was conducted. The actuator consisted of two asymmetric copper electrodes oriented normal to the flow separated by a dielectric barrier and mounted on a flat plate in the center of the tunnel. A contoured insert was constructed and used to create an adverse pressure gradient in the test section comparable to a Pak-B low pressure turbine blade distribution. Suction was applied from the upper wall to induce separation along the flat plate over the electrodes. The DC power supply was kept constant at 8.5 kV and power was regulated through a high voltage fast transistor switch. The pulse width of the switch remained at 250 ns with the frequency ranging from 25 to 100 Hz. All studies were conducted at a Reynolds number of 30,000 to simulate takeoff and other low speed conditions. It was found that the DC pulsed plasma actuator could reattach the flow but not consistently at these conditions. Furthermore no evidence was found to indicate that coherent vortical structures are responsible for reenergizing the boundary layer and controlling separatio

Future HAB science: Directions and challenges in a changing climate

There is increasing concern that accelerating environmental change attributed to human-induced warming of the planet may substantially alter the patterns, distribution and intensity of Harmful Algal Blooms (HABs). Changes in temperature, ocean acidification, precipitation, nutrient stress or availability, and the physical structure of the water column all influence the productivity, composition, and global range of phytoplankton assemblages, but large uncertainty remains about how integration of these climate drivers might shape future HABs. Presented here are the collective deliberations from a symposium on HABs and climate change where the research challenges to understanding potential linkages between HABs and climate were considered, along with new research directions to better define these linkages. In addition to the likely effects of physical (temperature, salinity, stratification, light, changing storm intensity), chemical (nutrients, ocean acidification), and biological (grazer) drivers on microalgae (senso lato), symposium participants explored more broadly the subjects of cyanobacterial HABs, benthic HABs, HAB effects on fisheries, HAB modelling challenges, and the contributions that molecular approaches can bring to HAB studies. There was consensus that alongside traditional research, HAB scientists must set new courses of research and practices to deliver the conceptual and quantitative advances required to forecast future HAB trends. These different practices encompass laboratory and field studies, long-term observational programs, retrospectives, as well as the study of socioeconomic drivers and linkages with aquaculture and fisheries. In anticipation of growing HAB problems, research on potential mitigation strategies should be a priority. It is recommended that a substantial portion of HAB research among laboratories be directed collectively at a small sub-set of HAB species and questions in order to fast-track advances in our understanding. Climate-driven changes in coastal oceanographic and ecological systems are becoming substantial, in some cases exacerbated by localized human activities. That, combined with the slow pace of decreasing global carbon emissions, signals the urgency for HAB scientists to accelerate efforts across disciplines to provide society with the necessary insights regarding future HAB trends

Human error in the design of a safety-critical system

From the introduction:This thesis is an investigation into some o f the causes and possible remedies to the problem of human error in a complex human-machine system. The system in question is engaged in the design of computer software for the control of railway signalling infrastructure. Error in its operation has the potential to be lethally destructive, a fact that provides not only the system’s epithet but also the primary motivation and significance for its investigation