Tislauskolonnin varopurkauksen laskeminen dynaamisen simuloinnin avulla

Työn tavoitteena oli tutkia tislauskolonnin dynamiikkaa ja dynaamista mallintamista simulointien avulla. Dynaamisen simulointimallin avulla selvitettiin pentaanin erotuskolonnin toimintaa poikkeus- ja häiriötilanteissa. Lisäksi pyrittiin arvioimaan työssä käytettyjen simulointiohjelmistojen soveltuvuutta tislauksen dynaamiseen simulointiin. Työn kirjallisuusosassa käsiteltiin tislauskolonnindynamiikan mallintamista matemaattisten mallien avulla sekä tislauskolonnimallin rakentamista simulointiohjelmistoon. Kirjallisuusosassa esiteltiin myös tislauskolonnin häiriötilanteita ja niiden aiheuttamia varopurkaustapauksia. Tämän lisäksi kirjallisuusosassa käytiin läpi tislauskolonnin varoventtiilien mitoittamisen perusteita. Työn soveltavassa osassa muodostettiin tislauskolonnille dynaaminen simulointimalli Aspen HYSYS Dynamics ja PROSimulator-simulointiohjelmistolla. Mallien avulla tarkasteltiin erilaisten häiriöiden ja poikkeustilanteiden vaikutusta kolonnin käyttäytymiseen ja varopurkaus-tapauksiin. Työssä arvioitiin myös ohjelmistojen soveltuvuutta tislauksen dynaamiseen simulointiin. Työssä saatujen tulosten perusteella voidaan todeta, että dynaamisen simuloinnin avulla saadaan hyödyllistä tietoa tislauskolonnin toiminnasta häiriö- ja poikkeustilanteissa. Dynaamisen simuloinnin onnistuminen ja luotettavien tulosten saaminen edellyttää kuitenkin tarkasteltavan prosessin tuntemista ja ohjelmiston käytön hallintaa. Työssä käytetyn Aspen HYSYS Dynamics simulointiohjelmiston käytettävyydessä havaittiin puutteita ja ohjelmisto vaatii vielä kehitystyötä. Työssä käytetty PROSimulator-simulointiohjelmisto soveltui pienistä puutteista huolimatta hyvin tislauskolonnin häiriötilanteiden tutkimiseen.

Using software metrics to increase efficiency in product creation

Opinnäytetyö etsii korrelaatiota ohjelmistomittauksella saavutettujen tulosten ja ohjelmasta löytyneiden virheiden väliltä. Työssä käytetään koeryhmänä jo olemassaolevia ohjelmistoja. Työ tutkii olisiko ohjelmistomittareita käyttämällä ollut mahdollista paikallistaa ohjelmistojen ongelmakohdat ja näin saada arvokasta tietoa ohjelmistokehitykseen. Mittausta voitaisiin käyttää resurssien parempaan kohdentamiseen koodikatselmuksissa, koodi-integraatiossa, systeemitestauksessa ja aikataulutuksessa. Mittaamisen avulla nämä tehtävät saisivat enemmän tietoa resurssien kohdistamiseen. Koeryhmänä käytetään erilaisia ohjelmistotuotteita. Yhteistä näille kaikille tuotteille on niiden peräkkäiset julkaisut. Uutta julkaisua tehtäessä, edellistä julkaisua käytetään pohjana, jonka päällekehitetään uutta lähdekoodia. Tämän takia ohjelmistomittauksessa pitää pystyä erottelemaan edellisen julkaisun lähdekoodi uudesta lähdekoodista. Työssä käytettävät ohjelmistomittarit ovat yleisiä ja ohjelmistotekniikassalaajasti käytettyjä mittaamaan erilaisia lähdekoodin ominaisuuksia, joiden arvellaan vaikuttavan virhealttiuteen. Tämän työn tarkoitus on tutkia näiden ohjelmistomittareiden käytettävyyttä koeryhmänä toimivissa ohjelmistoympäristöissä. Käytännön osuus työstä onnistui löytämään korrelaation joidenkinohjelmistomittareiden ja virheiden väliltä, samalla kuin toiset ohjelmistomittarit eivät antaneet vakuuttavia tuloksia. Ohjelmistomittareita käyttämällä näyttää olevan mahdollista tunnistaa virhealttiit kohdat ohjelmasta ja siten parantaa ohjelmistokehityksen tehokkuutta. Ohjelmistomittareiden käyttö tuotekehityksessäon perusteltavaa ja niiden avulla mahdollisesti pystyttäisiin vaikuttamaan ohjelmiston laatuun tulevissa julkaisuissa.

Modeling information in software languages

Ohjelmiston kehitystyökalut käyttävät infromaatiota kehittäjän tuottamasta lähdekoodista. Informaatiota hyödynnetään ohjelmistoprojektin eri vaiheissa ja eri tarkoituksissa. Moderneissa ohjelmistoprojekteissa käytetyn informaation määrä voi kasvaa erittäin suureksi. Ohjelmistotyökaluilla on omat informaatiomallinsa ja käyttömekanisminsa. Informaation määrä sekä erilliset työkaluinformaatiomallit tekevät erittäin hankalaksi rakentaa joustavaa työkaluympäristöä, erityisesti ongelma-aluekohtaiseen ohjelmiston kehitysprosessiin. Tässä työssä on analysoitu perusinformaatiometamalleja Unified Modeling language kielestä, Python ohjelmointikielestä ja C++ ohjelmointikielestä. Metainformaation taso on rajoitettu rakenteelliselle tasolle. Ajettavat rakenteet on jätetty pois. ModelBase metamalli on yhdistetty olemassa olevista analysoiduista metamalleista. Tätä metamallia voidaan käyttää tulevaisuudessa ohjelmistotyökalujen kehitykseen.

Managing an intellectual property right portfolio in the software industry

Tutkimuksen tavoitteena oli määrittää etuja, joita huolellinen immateriaali-oikeussalkun hallinnointi ohjelmistoalalla luo yritykselle. Tutkimusaineisto on kerätty haastattelemalla eri asemissa olevia ihmisiä kolmesta suomalaisesta ohjelmistoalan tuote- ja palveluyrityksestä. Tutkimuksesta käy ilmi, että ohjelmistoyritysten immateriaalioikeussalkut koostuvat liikesalaisuuksista, tekijänoikeudesta, tavaramerkeistä, verkkotunnuksista ja muutamista patenteista. Kiinnostus patentteihin ohjelmistoalalla on kasvanut erityisesti niiden tuoman tekijänoikeutta vahvemman suojan takia. Tällä hetkellä Euroopassa suhtautuminen ohjelmistopatentteihin on kuitenkin vielä käymistilassa. Jos ohjelmistopatentit hyväksytään, immateriaalioikeussalkun strateginen merkitys kasvaa. Tällöin salkunn hallinnointi tukee yrityksen tavoitteita - esimerkiksi oman toimintavapauden turvaamista - avustaen hakemus-prosessissa, tarkkaillen markkinoita sekä arvioiden yrityksen oman immateriaalioikeussalkun erilaisia hyväksikäyttömahdollisuuksia.

Software SMEs asStrategic Partners in the Partner Programs of Large International Companies

Tutkielman tavoitteena oli tutkia pienten- ja keskisuurten (PK) ohjelmistoyritysten kansainvälisiä kumppanuuksia. Päätavoitteena oli löytää keinoja kuinka PK-ohjelmistoyritykset voisivat tulla strategisiksi kumppaneksi suurten kansainvälisten yritysten kumppanuusohjelmissa. Lisäksi tutkielmassa oli tavoitteena selvittää kuinka kumppaneiden välistä sitoutumista voitaisiin vahvistaa, jotta PK-ohjelmistoyritykset voisivat saavuttaa todellista lisäarvoa ja kansainvälistä kasvua kumppanuusohjelmien kautta. Tutkielma jakaantuu teoreettiseen ja empiiriseen osaan. Teoreettinen osa keskittyy tarkastelemaan korkean teknologian markkinointia ohjelmistoalalla sekä kansainvälisiä kumppanuuksia. Suurten yritystenkumppanuusohjelmia ei ole tutkittu suomalaisten PK-ohjelmistoyritysten näkökulmasta, minkä vuoksi empiirinen tutkimus on perusteltua. Empiirinen tutkimus toteutettiin laadullisena case-tutkimuksena ja tutkimusmenetelmänä käytettiin puolistrukturoitua haastattelua. Tutkimustulokset osoittavat, että strategisen kumppanin aseman saavuttaminen on pitkä ja haastava matka PK-yrityksille. Suurten kansainvälisten yritysten kumppanuusohjelmat ovat useimmiten monimutkaisia ja todellisen lisäarvon saavuttaminen kumppanuusohjelman kautta vaatii paljon resursseja PK-yrityksiltä. Jotta PK-yritykset voisivat saavuttaa ja säilyttää strategisen kumppanin aseman kumppanuusohjelmassa, vaatii se aktiivista ja päivittäistä vuorovaikutusta kumppaneiden kesken. Erityisesti tiiviit henkilösuhteet oikeiden avainhenkilöiden kanssa ovat välttämättömyys. Läheiset kontaktit mahdollistavat sen, että PK-yritykset voivat ainakin osittain ohittaa kumppanuusohjelman byrokratian, mikä lisää luottamusta ja sitoutumista kumppanuussuhteessa sekä edistää kansainvälistä kasvua ja menestystä liiketoiminnassa.

ANÁLISIS, DISEÑO Y DESARROLLO DE UNA APLICACIÓN BAJO SOFTWARE LIBRE DESTINADO A EMPRENDIMIENTOS DEDICADOS A LA PRODUCCIÓN DE LECHE EN LA SIERRA ECUATORIANA

En esta memoria final se encuentra embebido la investigación realizada para poder generar una aplicación Web que permite registrar los procesos realizados para la producción de leche en el Cantón Cayambe de la provincia de Pichincha en Ecuador, el mismo que gracias a la ayuda del CILEC se pudo llevar a su culminación.En el primer capítulo de este documento se hace una breve introducción donde se profundiza la problemática del proyecto, así mismo se puntualiza los objetivos con los cuales se determina las directrices que dieron la guía al proyecto; en este capítulo también se topa brevemente sobre el estado del arte en el cual se puntualiza sobre los trabajos realizados hasta la actualidad.El segundo capítulo presenta el análisis realizado durante la recolección de requerimientos funcionales, deduciendo la automatización de los mismos, luego en mediante la aplicación de la metodología XP se pudo generar los diagramas que dieron el flujo del sistema. Aquí también se describe la estructura de la base de datos que se va a utilizar dentro de la aplicación. En consecución del diseño del sistema se procede a desarrollar la aplicación descrita en el tercer capítulo, donde se describe brevemente los paquetes creados y las configuraciones pertinentes, así mismo se plantea las pruebas de funcionamiento del sistema. En el cuarto capítulo se muestra los resultados de la aplicabilidad del sistema en función de los módulos determinados del sistema. Por último se expone las conclusiones como las referencias bibliográficas que se usó para el presente documento.

Improving globally distributed software development and support processes - A workflow view

We propose a new approach and related indicators for globally distributed software support and development based on a 3-year process improvement project in a globally distributed engineering company. The company develops, delivers and supports a complex software system with tailored hardware components and unique end-customer installations. By applying the domain knowledge from operations management on lead time reduction and its multiple benefits to process performance, the workflows of globally distributed software development and multitier support processes were measured and monitored throughout the company. The results show that the global end-to-end process visibility and centrally managed reporting at all levels of the organization catalyzed a change process toward significantly better performance. Due to the new performance indicators based on lead times and their variation with fixed control procedures, the case company was able to report faster bug-fixing cycle times, improved response times and generally better customer satisfaction in its global operations. In all, lead times to implement new features and to respond to customer issues and requests were reduced by 50%.

Observations on Software Testing Practice

This thesis investigates factors that affect software testing practice. The thesis consists of empirical studies, in which the affecting factors were analyzed and interpreted using quantitative and qualitative methods. First, the Delphi method was used to specify the scope of the thesis. Secondly, for the quantitative analysis 40industry experts from 30 organizational units (OUs) were interviewed. The survey method was used to explore factors that affect software testing practice. Conclusions were derived using correlation and regression analysis. Thirdly, from these 30 OUs, five were further selected for an in-depth case study. The data was collected through 41 semi-structured interviews. The affecting factors and their relationships were interpreted with qualitative analysis using grounded theory as the research method. The practice of software testing was analyzed from the process improvement and knowledge management viewpoints. The qualitative and quantitativeresults were triangulated to increase the validity of the thesis. Results suggested that testing ought to be adjusted according to the business orientation of the OU; the business orientation affects the testing organization and knowledge management strategy, and the business orientation andthe knowledge management strategy affect outsourcing. As a special case, the complex relationship between testing schedules and knowledge transfer is discussed. The results of this thesis can be used in improvingtesting processes and knowledge management in software testing.

Selective catalytic reduction of nitrogen oxides with ammonia in forced unsteady state reactors - Case based reasoning and mathematical model simulation reasoning

The application of forced unsteady-state reactors in case of selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3) is sustained by the fact that favorable temperature and composition distributions which cannot be achieved in any steady-state regime can be obtained by means of unsteady-state operations. In a normal way of operation the low exothermicity of the selective catalytic reduction (SCR) reaction (usually carried out in the range of 280-350°C) is not enough to maintain by itself the chemical reaction. A normal mode of operation usually requires supply of supplementary heat increasing in this way the overall process operation cost. Through forced unsteady-state operation, the main advantage that can be obtained when exothermic reactions take place is the possibility of trapping, beside the ammonia, the moving heat wave inside the catalytic bed. The unsteady state-operation enables the exploitation of the thermal storage capacity of the catalyticbed. The catalytic bed acts as a regenerative heat exchanger allowing auto-thermal behaviour when the adiabatic temperature rise is low. Finding the optimum reactor configuration, employing the most suitable operation model and identifying the reactor behavior are highly important steps in order to configure a proper device for industrial applications. The Reverse Flow Reactor (RFR) - a forced unsteady state reactor - corresponds to the above mentioned characteristics and may be employed as an efficient device for the treatment of dilute pollutant mixtures. As a main disadvantage, beside its advantages, the RFR presents the 'wash out' phenomena. This phenomenon represents emissions of unconverted reactants at every switch of the flow direction. As a consequence our attention was focused on finding an alternative reactor configuration for RFR which is not affected by the incontrollable emissions of unconverted reactants. In this respect the Reactor Network (RN) was investigated. Its configuration consists of several reactors connected in a closed sequence, simulating a moving bed by changing the reactants feeding position. In the RN the flow direction is maintained in the same way ensuring uniformcatalyst exploitation and in the same time the 'wash out' phenomena is annulated. The simulated moving bed (SMB) can operate in transient mode giving practically constant exit concentration and high conversion levels. The main advantage of the reactor network operation is emphasizedby the possibility to obtain auto-thermal behavior with nearly uniformcatalyst utilization. However, the reactor network presents only a small range of switching times which allow to reach and to maintain an ignited state. Even so a proper study of the complex behavior of the RN may give the necessary information to overcome all the difficulties that can appear in the RN operation. The unsteady-state reactors complexity arises from the fact that these reactor types are characterized by short contact times and complex interaction between heat and mass transportphenomena. Such complex interactions can give rise to a remarkable complex dynamic behavior characterized by a set of spatial-temporal patterns, chaotic changes in concentration and traveling waves of heat or chemical reactivity. The main efforts of the current research studies concern the improvement of contact modalities between reactants, the possibility of thermal wave storage inside the reactor and the improvement of the kinetic activity of the catalyst used. Paying attention to the above mentioned aspects is important when higher activity even at low feeding temperatures and low emissions of unconverted reactants are the main operation concerns. Also, the prediction of the reactor pseudo or steady-state performance (regarding the conversion, selectivity and thermal behavior) and the dynamicreactor response during exploitation are important aspects in finding the optimal control strategy for the forced unsteady state catalytic tubular reactors. The design of an adapted reactor requires knowledge about the influence of its operating conditions on the overall process performance and a precise evaluation of the operating parameters rage for which a sustained dynamic behavior is obtained. An apriori estimation of the system parameters result in diminution of the computational efforts. Usually the convergence of unsteady state reactor systems requires integration over hundreds of cycles depending on the initial guess of the parameter values. The investigation of various operation models and thermal transfer strategies give reliable means to obtain recuperative and regenerative devices which are capable to maintain an auto-thermal behavior in case of low exothermic reactions. In the present research work a gradual analysis of the SCR of NOx with ammonia process in forced unsteady-state reactors was realized. The investigation covers the presentationof the general problematic related to the effect of noxious emissions in the environment, the analysis of the suitable catalysts types for the process, the mathematical analysis approach for modeling and finding the system solutions and the experimental investigation of the device found to be more suitable for the present process. In order to gain information about the forced unsteady state reactor design, operation, important system parameters and their values, mathematical description, mathematicalmethod for solving systems of partial differential equations and other specific aspects, in a fast and easy way, and a case based reasoning (CBR) approach has been used. This approach, using the experience of past similarproblems and their adapted solutions, may provide a method for gaining informations and solutions for new problems related to the forced unsteady state reactors technology. As a consequence a CBR system was implemented and a corresponding tool was developed. Further on, grooving up the hypothesis of isothermal operation, the investigation by means of numerical simulation of the feasibility of the SCR of NOx with ammonia in the RFRand in the RN with variable feeding position was realized. The hypothesis of non-isothermal operation was taken into account because in our opinion ifa commercial catalyst is considered, is not possible to modify the chemical activity and its adsorptive capacity to improve the operation butis possible to change the operation regime. In order to identify the most suitable device for the unsteady state reduction of NOx with ammonia, considering the perspective of recuperative and regenerative devices, a comparative analysis of the above mentioned two devices performance was realized. The assumption of isothermal conditions in the beginningof the forced unsteadystate investigation allowed the simplification of the analysis enabling to focus on the impact of the conditions and mode of operation on the dynamic features caused by the trapping of one reactant in the reactor, without considering the impact of thermal effect on overall reactor performance. The non-isothermal system approach has been investigated in order to point out the important influence of the thermal effect on overall reactor performance, studying the possibility of RFR and RN utilization as recuperative and regenerative devices and the possibility of achieving a sustained auto-thermal behavior in case of lowexothermic reaction of SCR of NOx with ammonia and low temperature gasfeeding. Beside the influence of the thermal effect, the influence of the principal operating parameters, as switching time, inlet flow rate and initial catalyst temperature have been stressed. This analysis is important not only because it allows a comparison between the two devices and optimisation of the operation, but also the switching time is the main operating parameter. An appropriate choice of this parameter enables the fulfilment of the process constraints. The level of the conversions achieved, the more uniform temperature profiles, the uniformity ofcatalyst exploitation and the much simpler mode of operation imposed the RN as a much more suitable device for SCR of NOx with ammonia, in usual operation and also in the perspective of control strategy implementation. Theoretical simplified models have also been proposed in order to describe the forced unsteady state reactors performance and to estimate their internal temperature and concentration profiles. The general idea was to extend the study of catalytic reactor dynamics taking into account the perspectives that haven't been analyzed yet. The experimental investigation ofRN revealed a good agreement between the data obtained by model simulation and the ones obtained experimentally.

On Effort Estimation in Software Projects

Software engineering is criticized as not being engineering or 'well-developed' science at all. Software engineers seem not to know exactly how long their projects will last, what they will cost, and will the software work properly after release. Measurements have to be taken in software projects to improve this situation. It is of limited use to only collect metrics afterwards. The values of the relevant metrics have to be predicted, too. The predictions (i.e. estimates) form the basis for proper project management. One of the most painful problems in software projects is effort estimation. It has a clear and central effect on other project attributes like cost and schedule, and to product attributes like size and quality. Effort estimation can be used for several purposes. In this thesis only the effort estimation in software projects for project management purposes is discussed. There is a short introduction to the measurement issues, and some metrics relevantin estimation context are presented. Effort estimation methods are covered quite broadly. The main new contribution in this thesis is the new estimation model that has been created. It takes use of the basic concepts of Function Point Analysis, but avoids the problems and pitfalls found in the method. It is relativelyeasy to use and learn. Effort estimation accuracy has significantly improved after taking this model into use. A major innovation related to the new estimationmodel is the identified need for hierarchical software size measurement. The author of this thesis has developed a three level solution for the estimation model. All currently used size metrics are static in nature, but this new proposed metric is dynamic. It takes use of the increased understanding of the nature of the work as specification and design work proceeds. It thus 'grows up' along with software projects. The effort estimation model development is not possible without gathering and analyzing history data. However, there are many problems with data in software engineering. A major roadblock is the amount and quality of data available. This thesis shows some useful techniques that have been successful in gathering and analyzing the data needed. An estimation process is needed to ensure that methods are used in a proper way, estimates are stored, reported and analyzed properly, and they are used for project management activities. A higher mechanism called measurement framework is also introduced shortly. The purpose of the framework is to define and maintain a measurement or estimationprocess. Without a proper framework, the estimation capability of an organization declines. It requires effort even to maintain an achieved level of estimationaccuracy. Estimation results in several successive releases are analyzed. It isclearly seen that the new estimation model works and the estimation improvementactions have been successful. The calibration of the hierarchical model is a critical activity. An example is shown to shed more light on the calibration and the model itself. There are also remarks about the sensitivity of the model. Finally, an example of usage is shown.

A mathematical study of fuzzy logic; an algebraic approach

Fuzzy set theory and Fuzzy logic is studied from a mathematical point of view. The main goal is to investigatecommon mathematical structures in various fuzzy logical inference systems and to establish a general mathematical basis for fuzzy logic when considered as multi-valued logic. The study is composed of six distinct publications. The first paper deals with Mattila'sLPC+Ch Calculus. THis fuzzy inference system is an attempt to introduce linguistic objects to mathematical logic without defining these objects mathematically.LPC+Ch Calculus is analyzed from algebraic point of view and it is demonstratedthat suitable factorization of the set of well formed formulae (in fact, Lindenbaum algebra) leads to a structure called ET-algebra and introduced in the beginning of the paper. On its basis, all the theorems presented by Mattila and many others can be proved in a simple way which is demonstrated in the Lemmas 1 and 2and Propositions 1-3. The conclusion critically discusses some other issues of LPC+Ch Calculus, specially that no formal semantics for it is given.In the second paper the characterization of solvability of the relational equation RoX=T, where R, X, T are fuzzy relations, X the unknown one, and o the minimum-induced composition by Sanchez, is extended to compositions induced by more general products in the general value lattice. Moreover, the procedure also applies to systemsof equations. In the third publication common features in various fuzzy logicalsystems are investigated. It turns out that adjoint couples and residuated lattices are very often present, though not always explicitly expressed. Some minor new results are also proved.The fourth study concerns Novak's paper, in which Novak introduced first-order fuzzy logic and proved, among other things, the semantico-syntactical completeness of this logic. He also demonstrated that the algebra of his logic is a generalized residuated lattice. In proving that the examination of Novak's logic can be reduced to the examination of locally finite MV-algebras.In the fifth paper a multi-valued sentential logic with values of truth in an injective MV-algebra is introduced and the axiomatizability of this logic is proved. The paper developes some ideas of Goguen and generalizes the results of Pavelka on the unit interval. Our proof for the completeness is purely algebraic. A corollary of the Completeness Theorem is that fuzzy logic on the unit interval is semantically complete if, and only if the algebra of the valuesof truth is a complete MV-algebra. The Compactness Theorem holds in our well-defined fuzzy sentential logic, while the Deduction Theorem and the Finiteness Theorem do not. Because of its generality and good-behaviour, MV-valued logic can be regarded as a mathematical basis of fuzzy reasoning. The last paper is a continuation of the fifth study. The semantics and syntax of fuzzy predicate logic with values of truth in ana injective MV-algerba are introduced, and a list of universally valid sentences is established. The system is proved to be semanticallycomplete. This proof is based on an idea utilizing some elementary properties of injective MV-algebras and MV-homomorphisms, and is purely algebraic.

A Semantic wiki for quality management in software development projects

Quality management has become a strategic issue for organisations and is very valuable to produce quality software. However, quality management systems (QMS) are not easy to implement and maintain. The authors' experience shows the benefits of developing a QMS by first formalising it using semantic web ontologies and then putting them into practice through a semantic wiki. The QMS ontology that has been developed captures the core concepts of a traditional QMS and combines them with concepts coming from the MPIu'a development process model, which is geared towards obtaining usable and accessible software products. Then, the ontology semantics is directly put into play by a semantics-aware tool, the Semantic MediaWiki. The developed QMS tool is being used for 2 years by the GRIHO research group, where it has manages almost 50 software development projects taking into account the quality management issues. It has also been externally audited by a quality certification organisation. Its users are very satisfied with their daily work with the tool, which manages all the documents created during project development and also allows them to collaborate, thanks to the wiki features.

Learning through Computer Model Improvisations

It has been convincingly argued that computer simulation modeling differs from traditional science. If we understand simulation modeling as a new way of doing science, the manner in which scientists learn about the world through models must also be considered differently. This article examines how researchers learn about environmental processes through computer simulation modeling. Suggesting a conceptual framework anchored in a performative philosophical approach, we examine two modeling projects undertaken by research teams in England, both aiming to inform flood risk management. One of the modeling teams operated in the research wing of a consultancy firm, the other were university scientists taking part in an interdisciplinary project experimenting with public engagement. We found that in the first context the use of standardized software was critical to the process of improvisation, the obstacles emerging in the process concerned data and were resolved through exploiting affordances for generating, organizing, and combining scientific information in new ways. In the second context, an environmental competency group, obstacles were related to the computer program and affordances emerged in the combination of experience-based knowledge with the scientists' skill enabling a reconfiguration of the mathematical structure of the model, allowing the group to learn about local flooding.

Observations on Software Project Deviations

Software projects have proved to be troublesome to be implemented and as the size of software keeps increasing it is more and more important to follow-up the projects. The proportion of succeeded software projects is still quite low in spite of the research and the development of the project control methodologies. The success and failure factors of projects are known, as well as the project risks but nevertheless the projects still have problems with keeping the schedule and the budget and achieving the defined functionality and adequate quality. The purpose of this thesis was to find out what deviations are there in projects at the moment, what causes them, and what is measured in projects. Also project deviation was defined in the viewpoint of literature and field experts. The analysis was made using a qualitative research approach. It was found out that there are still deviations in software projects with schedule, budget, quality, requirements, documenting, effort, and resources. In addition also changes in requirements were identified. It was also found out that for example schedule deviations can be affected by reducing the size of a task and adding measurements.