91 |
Semantics, verification, and implementation of workflows with cancellation regions and OR-joinsWynn, Moe Thandar January 2006 (has links)
Workflow systems aim to provide automated support for the conduct of certain business processes. Workflow systems are driven by workflow specifications which among others, capture the execution interdependencies between various activities. These interdependencies are modelled by means of different control flow constructors, e.g., sequence, choice, parallelism and synchronisation. It has been shown in the research on workflow patterns that the support for and the interpretation of various control flow constructs varies substantially across workflow systems. Two of the most problematic patterns relate to the OR-join and to cancellation. An OR-join is used in situations when we need to model " wait and see" behaviour for synchronisation. Different approaches assign a different (often only intuitive) semantics to this type of join, though they do share the common theme that synchronisation is only to be performed for active paths. Depending on context assumptions this behaviour may be relatively easy to deal with, though in general its semantics is complicated, both from a definition point of view (in terms of formally capturing a desired intuitive semantics) and from a computational point of view (how does one determine whether an OR-join is enabled?). Many systems and languages struggle with the semantics and implementation of the OR-join because its non-local semantics require a synchronisation depending on an analysis of future execution paths. This may require some non-trivial reasoning. The presence of cancellation features and other OR-joins in a workflow further complicates the formal semantics of the OR-join. The cancellation feature is commonly used to model external events that can change the behaviour of a running workflow. It can be used to either disable activities in certain parts of a workflow or to stop currently running activities. Even though it is possible to cancel activities in workflow systems using some sort of abort function, many workflow systems do not provide direct support for this feature in the workflow language. Sometimes, cancellation affects only a selected part of a workflow and other activities can continue after performing a cancellation action. As cancellation occurs naturally in business scenarios, comprehensive support in a workflow language is desirable. We take on the challenge of providing formal semantics, verification techniques as well as an implementation for workflows with those features. This thesis addresses three interrelated issues for workflows with cancellation regions and OR-joins. The concept of the OR-join is examined in detail in the context of the workflow language YAWL, a powerful workflow language designed to support a collection of workflow patterns and inspired by Petri nets. The OR-join semantics has been redesigned to represent a general, formal, and decidable approach for workflows in the presence of cancellation regions and other OR-joins. This approach exploits a link that is proposed between YAWL and reset nets, a variant of Petri nets with a special type of arc that can remove all tokens from a place. Next, we explore verification techniques for workflows with cancellation regions and OR-joins. Four structural properties have been identified and a verification approach that exploits coverability and reachability notions from reset nets has been proposed. The work on verification techniques has highlighted potential problems with calculating state spaces for large workflows. Applying reduction rules before carrying out verification can decrease the size of the problem by cutting down the size of the workflow that needs to be examined while preserving some essential properties. Therefore, we have extended the work on verification by proposing reduction rules for reset nets and for YAWL nets with and without OR-joins. The proposed OR-join semantics as well as the proposed verification approach have been implemented in the YAWL environment.
|
92 |
Modélisation hydrologique distribuée des crues en région Cévennes-Vivarais : impact des incertitudes liées à l'estimation des précipitations et à la paramétrisation du modèle / Distributed hydrological modeling of floods in the Cévennes-Vivarais region : impact of uncertainties related to precipitation estimation and model parameterization / Modelización hidrológica distribuida de crecidas en la región del Cévennes-Vivarais : impacto de incertidumbres ligadas a la estimación de la precipitación y a la parametrización del modeloNavas Nunez, Rafael 06 October 2017 (has links)
Il est connu qu’avoir un système d’observation de la pluie de haute résolution spatio – temporelle est crucial pour obtenir de bons résultats dans la modélisation pluie – écoulement. Le radar est un outil qui donne des estimations quantitatives de precipitation avec une très bonne résolution. Lorsqu’il est fusionné avec un réseau des pluviomètres les avantages des deux systèmes sont obtenus. Cependant, les estimations fournies par le radar ont des incertitudes différentes à celles qui sont obtenus avec les pluviomètres. Dans le processus de calcul pluie – écoulement l'incertitude des précipitations interagit avec l'incertitude du modèle hydrologique. L’objectif de ce travail est d’étudier les méthodes utilisées pour quantifier l'incertitude dans l'estimation des précipitations par fusion radar – pluviomètres et de l'incertitude dans la modélisation hydrologique, afin de développer une méthodologie d'analyse de leurs contributions individuelles au traitement pluie - écoulement.Le travail est divisé en deux parties, la première cherche à évaluer: Comment peut-on quantifier l'incertitude de l'estimation des précipitations par radar? Pour répondre à la question, l'approche géostatistique par Krigeage avec Dérive Externe (KED) et Génération Stochastique de la précipitation a été utilisée, qui permet de modéliser la structure spatio – temporaire de l’erreur. La méthode a été appliquée dans la région des Cévennes - Vivarais (France), où il y a un système très dense d'observation. La deuxième partie explique: Comment pourrais être quantifiée l'incertitude de la simulation hydrologique qui provient de l'estimation de précipitation par radar et du processus de modélisation hydrologique? Dans ce point, l'outil de calcul hydrologique à Mesoéchelle (HCHM) a été développé, c’est un logiciel hydrologique distribuée et temps continu, basé sur le Numéro de Courbe et l’Hydrographe Unitaire. Il a été appliqué dans 20 résolutions spatio - temporelles allant de 10 à 300 km2 et 1 à 6 heures dans les bassins de l’Ardèche (~ 1971 km2) et le Gardon (1810 km2). Apres une analyse de sensibilité, le modèle a été simplifié avec 4 paramètres et l’incertitude de la chaîne de processus a été analysée: 1) Estimation de precipitation; 2) Modélisation hydrologique; et 3) Traitement pluie - écoulement, par l’utilisation du coefficient de variation de l'écoulement simulé.Il a été montré que KED est une méthode qui fournit l’écart type de l’estimation des précipitations, lequel peut être transformé dans une estimation stochastique de l’erreur locale. Dans la chaîne des processus: 1) L'incertitude dans l'estimation de précipitation augmente avec la réduction de l’échelle spatio – temporelle, et son effet est atténué par la modélisation hydrologique, vraisemblablement par les propriétés de stockage et de transport du bassin ; 2) L'incertitude de la modélisation hydrologique dépend de la simplification des processus hydrologiques et pas de la surface du bassin ; 3) L'incertitude dans le traitement pluie - écoulement est le résultat de la combinaison amplifiée des incertitudes de la précipitation et la modélisation hydrologique. / It is known that having a precipitation observation system at high space - time resolution is crucial to obtain good results in rainfall - runoff modeling. Radar is a tool that offers quantitative precipitation estimates with very good resolution. When it is merged with a rain gauge network the advantages of both systems are achieved. However, radars estimates have different uncertainties than those obtained with the rain gauge. In the modeling process, uncertainty of precipitation interacts with uncertainty of the hydrological model. The objective of this work is: To study methods used to quantify the uncertainty in radar – raingauge merge precipitation estimation and uncertainty in hydrological modeling, in order to develop a methodology for the analysis of their individual contributions in the uncertainty of rainfall - runoff estimation.The work is divided in two parts, the first one evaluates: How the uncertainty of radar precipitation estimation can be quantified? To address the question, the geostatistical approach by Kriging with External Drift (KED) and Stochastic Generation of Precipitation was used, which allows to model the spatio - temporal structure of errors. The method was applied in the Cévennes - Vivarais region (France), where there is a very rich observation system. The second part explains: How can it be quantified the uncertainty of the hydrological simulation coming from the radar precipitation estimates and hydrological modeling process? In this point, the hydrological mesoscale computation tool was developed; it is distributed hydrological software in time continuous, within the basis of the Curve Number and the Unit Hydrograph. It was applied in 20 spatio-temporal resolutions ranging from 10 to 300 km2 and 1 to 6 hours in the Ardèche (~ 1971 km2) and the Gardon (1810 km2) basins. After a sensitivity analysis, the model was simplified with 4 parameters and the uncertainty of the chain of process was analyzed: 1) Precipitation estimation; 2) Hydrological modeling; and 3) Rainfall - runoff estimation, by using the coefficient of variation of the simulated flow.It has been shown that KED is a method that provides the standard deviation of the precipitation estimation, which can be transformed into a stochastic estimation of the local error. In the chain of processes: 1) Uncertainty in precipitation estimation increases with decreasing spatio-temporal scale, and its effect is attenuated by hydrological modeling, probably due by storage and transport properties of the basin; 2) The uncertainty of hydrological modeling depends on the simplification of hydrological processes and not on the surface of the basin; 3) Uncertainty in rainfall - runoff treatment is the result of the amplified combination of precipitation and hydrologic modeling uncertainties.
|
93 |
Algoritmo ejeção-absorção metropolizado para segmentação de imagensCalixto, Alexandre Pitangui 19 December 2014 (has links)
Made available in DSpace on 2016-06-02T20:04:53Z (GMT). No. of bitstreams: 1
6510.pdf: 2213423 bytes, checksum: 0c9b206a1b5f88772031ed160e9691b3 (MD5)
Previous issue date: 2014-12-19 / Financiadora de Estudos e Projetos / We proposed a new split-merge MCMC algorithm for image segmentation. We describe how an image can be subdivided into multiple disjoint regions, with each region having an associated latent indicator variable. The latent indicator variables are modeled with a prior Gibbs distribution governed by a spatial regularization parameter. Regions with same label define a component. Pixels within a component are distributed according to a Gaussian distribution. We treat the spatial regularization parameter and the number of components K as unknown. To estimate K, the spatial regularization parameter and the component parameters we propose the Metropolised split-merge (MSM) algorithm. The MSM comprises two type of moves. The first one, is a data-driven split-merge move. These movements change the number of components K in the neighborhood K _ 1 and are accepted according to Metropolis-Hastings acceptance probability. After a split-merge step, the component parameters, the spatial regularization parameter and latent allocation variables are updated conditional on K by using the Gibbs sampling, the Metropolis- Hastings and Swendsen-Wang algorithm, respectively. The main advantage of the proposed algorithm is that it is easy to implement and the acceptance probability for split-merge movements depends only of the observed data. The performance of the proposed algorithm is verified using artificial datasets as well as real datasets. / Nesta tese, modelamos uma imagem através de uma grade regular retangular e assumimos que esta grade é dividida em múltiplas regiões disjuntas de pixels. Quando duas ou mais regiões apresentam a mesma característica, a união dessas regiões forma um conjunto chamado de componente. Associamos a cada pixel da imagem uma variável indicadora não observável que indica a componente a que o pixel pertence. Estas variáveis indicadoras não observáveis são modeladas através da distribuição de probabilidade de Gibbs com parâmetro de regularização espacial _. Assumimos que _ e o número de componentes K são desconhecidos. Para estimação conjunta dos parâmetros de interesse, propomos um algoritmo MCMC denominado de ejeção-absorção metropolizado (EAM). Algumas vantagens do algoritmo proposto são: (i) O algoritmo não necessita da especificação de uma função de transição para realização dos movimentos ejeção e absorção. Ao contrário do algoritmo reversible jump (RJ) que requer a especificação de boas funções de transição para ser computacionalmente eficiente; (ii) Os movimentos ejeção e absorção são desenvolvidos com base nos dados observados e podem ser rapidamente propostos e testados; (iii) Novas componentes são criadas com base em informações provenientes de regiões de observações e os parâmetros das novas componentes são gerados das distribuições a posteriori. Ilustramos o desempenho do algoritmo EAM utilizando conjuntos de dados simulados e reais.
|
94 |
Comparing integration effort and correctness of different merge approaches in version control systemsCAVALCANTI, Guilherme José Carvalho 29 February 2016 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-09-27T18:16:18Z
No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
dissertação_gjcc.pdf: 1929523 bytes, checksum: 59a910a15e3537942754d106de378d19 (MD5) / Made available in DSpace on 2016-09-27T18:16:18Z (GMT). No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
dissertação_gjcc.pdf: 1929523 bytes, checksum: 59a910a15e3537942754d106de378d19 (MD5)
Previous issue date: 16-02-29 / FACEPE / During the integration of code contributions resulting from development tasks, one likely has to deal with conflicting changes and dedicate substantial effort to resolve conflicts. While unstructured merge tools try to automatically resolve part of the conflicts via textual similarity, semistructured tools try to go further by exploiting the syntactic structure of part of the artefacts involved. To understand the impact of the unstructured and semistructured merge approaches on integration effort (Productivity) and correctness of the merging process (Quality), we conduct two empirical studies. In the first one, aiming at increasing the existing body of evidence and assessing results for systems developed under an alternative version control paradigm, we replicate an experiment to compare the unstructured and semistructured approaches with respect to the number of conflicts reported by both merge approaches. We used both semistructured and unstructured merge in a sample 2.5 times bigger than the original study regarding the number of projects and 18 times bigger regarding the number of performed merges, and we compared the occurrence of conflicts. Similar to the original study, we observed that semistructured merge reduces the number of conflicts in 55% of the performed merges of the new sample. Besides that, the observed average conflict reduction of 62% in these merges is far superior than what has been observed before. We also bring new evidence that the use of semistructured merge can reduce the occurrence of conflicting merges by half. In order to verify the frequency of false positives and false negatives arising from the use of these merge approaches, we move forward and we conduct a second empirical study. We compare the unstructured and semistructured merge approaches by reproducing more than 30,000 merges from 50 projects, and collecting evidence about reported conflicts that do not represent interferences between development tasks (false positives), and interferences not reported as conflicts (false negatives). In particular, our assumption is that false positives amount to unnecessary integration effort because developers have to resolve conflicts that actually do not represent interferences. Besides that, false negatives amount to build issues or bugs, negatively impacting software quality and correctness of the merging process. By analyzing such critical factors we hope to guide developers on deciding which approach should be used in practice. Finally, our results show that semistructured merge eliminates a significant part of the false positives reported by unstructured merge, but brings false positives of its own. The overall number of false positives is reduced with semistructured merge, and we argue that the conflicts associated to its false positives are easier to resolve when comparing to the false positives reported by unstructured merge. We also observe that more interferences were missed by unstructured merge and reported by semistructured merge, but we argue that the semistructured merge ones are harder to detect and resolve than the other way around. Finally, our study suggests how a semistructured merge tool could be improved to eliminate the extra false positives and negatives it has in relation to unstructured merge. / Durante a integração de contribuições de código resultantes das tarefas de desenvolvimento,
frequentemente desenvolvedores têm que lidar com alterações conflitantes e dedicar considerável esforço para resolver conflitos. Enquanto as ferramentas de integração não-estruturadas tentam resolver automaticamente parte dos conflitos através de similaridade textual, ferramentas semiestruturadas tentam ir mais longe, explorando a estrutura sintática de parte dos artefatos envolvidos. Para entender o impacto das abordagens de integração não-estruturada e semiestruturada sobre esforço de integração (Produtividade) e corretude do processo de integração (Qualidade), nós realizamos dois estudos empíricos. No primeiro, com o objetivo de aumentar o atual corpo de evidência e avaliar resultados para sistemas desenvolvidos usando um paradigma de controle de versão alternativo, nós replicamos um experimento para comparar a abordagem não-estruturada e semiestruturada de acordo com o número de conflitos reportados por ambas as abordagens. Nós usamos tanto a integração semiestruturada quanto a não-estruturada em uma amostra 2,5 vezes maior do que a do estudo original em relação ao número de projetos e 18 vezes maior em relação ao número de integrações realizadas, e comparamos a ocorrência de conflitos. Semelhante ao estudo original, observamos que a integração semiestruturada reduz o número de conflitos em 55% das integrações da nova amostra. Além disso, a redução de conflitos média observada de 62% nestas integrações é muito superior à observada anteriormente. Nós também trazemos nova evidência de que o uso da abordagem semiestruturada pode reduzir a ocorrência de integrações com conflitos pela metade. Com o intuito de verificar a frequência de falsos positivos e falsos negativos originados do uso dessas abordagens, nós seguimos adiante e conduzimos um segundo estudo empírico. Nós comparamos as abordagens reproduzindo mais de 30.000 integrações de 50 projetos, coletando evidência sobre os conflitos reportados que não representam interferências entre as tarefas de desenvolvimento (falsos positivos), e interferências não reportadas como conflitos (falsos negativos). Em particular, a nossa suposição é de que falsos positivos denotam esforço desnecessário de integração porque os desenvolvedores têm que resolver conflitos que, na realidade, não representam interferências. Além disso, falsos negativos denotam problemas de build ou bugs, impactando negativamente a qualidade do software e corretude do processo de integração. Ao analisar esses fatores críticos, esperamos orientar os desenvolvedores em decidir qual abordagem deve ser usada na prática. Finalmente, nossos resultados mostram que a abordagem semiestruturada elimina uma parte significativa dos falsos positivos reportados pela abordagem não-estruturada, mas traz falsos positivos próprios. O número global de falsos positivos é reduzido com a integração semiestruturada, e nós argumentamos que os conflitos associados aos seus falsos positivos são mais fáceis de resolver quando comparados aos falsos positivos reportados pela abordagem não-estruturada. Observamos, também, que mais interferências deixaram de ser detectadas pela abordagem não-estruturada, mas foram detectadas pela semiestruturada. No entanto, nós acreditamos que as interferências não detectadas pela abordagem semiestruturada são mais difíceis de detectar e resolver. Por fim, nosso estudo sugere como uma ferramenta de integração semiestruturada poderia ser melhorada para eliminar os falsos positivos e falsos negativos adicionados que possui em relação à não-estruturada.
|
95 |
TU-Spektrum 2/2015, Magazin der Technischen Universität ChemnitzSteinebach, Mario, Thehos, Katharina, Geipel, Karina, Preuß, Katharina, Ramdani, Yasmina, Schäfer, Andy, Schäfer, Sabrina 27 November 2015 (has links) (PDF)
unregelmäßig erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz
|
96 |
Vliv rozšíření konsolidačního celku na ekonomickou situaci koncernu / The Impact of The Consolidation on The Economic Situation of The CompanyPíšová, Klára January 2019 (has links)
The thesis deals with the issue of consolidated financial statement in a selected holding and in its economic appreciation before the expansion of the consolidated group and after its change. The first part of the thesis includes theoretical knowledge for consolidated financial statement which are subsequently applied in the creation of new consolidated financial statements related to the expansion of the consolidated group. The conclusion of the thesis is dedicted to the comparison of consolidated financial statements.
|
97 |
Fúze dceřiných obchodních společností / Merger of Daughter CompaniesKrýsa, Pavel January 2010 (has links)
This work deals with mergers of commertial companys in largers economic units. Chapters are systematicly organized and provide the reader with overview of the development, relevant issues and execution of mergers of commercial companies. The work shows styles of merger execution, company´s motives for merger and finally also legal regulations connected with this proccess. Other sections of this work show analyses of companies, which have undergone a merger. You can see characteristics of these organisations and compare their merger execution plans and detailed schedule for different stages of the merge project.
|
98 |
The Infrastructure for Cultural Adoption: An Investigation in the Field of Mergers and AcquisitionsSäisä, Johan, Ragnås, Daniela January 2013 (has links)
This master thesis investigates how an infrastructure for cultural adoption in a merger and acquisition integration could be designed. This research is valuable since prior research indicate that culture plays an important role in the success of integrating an acquired firm into the acquirer’s organization. However, there has been no research conducted in the field of how the culture should be regarded for. Our research took place at the Stockholm office of Logica, an Information Technology (IT) consultancy company which was acquired by CGI in August 2012. We have by the means of interviews and observations through our study at the case company derived numerous factors which all have a positive impact on the cultural adoption. These factors have then been categorized into three major themes; Experience, Planning, and Communication. These themes, and thus also factors, are not entirely independent but rather impose effects on each other, most notably in the case of experience. However, it is still our suggestion that the infrastructure for cultural adoption in a merger and acquisition (M&A) integration should address these three topics. Furthermore, it is in our beliefs that if these areas are addressed, the frequently recurring problem of unsuccessful M&As due to the neglecting of culture can be managed. And hopefully, by applying an infrastructural approach, it will aid the cultural adoption and moreover increase the probability of a successful M&A integration.
|
99 |
TU-Spektrum 1/2016, Magazin der Technischen Universität ChemnitzSteinebach, Mario, Thehos, Katharina, Geipel, Karina, Preuß, Katharina, Schäfer, Andy, Schäfer, Sabrina 12 April 2016 (has links)
unregelmäßig erscheinende Zeitschrift über aktuelle Themen der TU Chemnitz
|
100 |
台灣金融產業融資購併之個案分析林建平, Lin, Chien Ping Unknown Date (has links)
台新金控購併彰化銀行可以說是台灣金融業擬以融資購併方式進行合併的第一案,本研究希望透過分析此個案,了解台新金控購併的目的、資金來源與後續合併換股可能衍生之議題,為未來公股釋出,以及金融整併提供可行之方法。
本文就融資購併理論架構說明起,以當前台灣金融政策與購併環境現況分析,這包括實際已發生的金融購併案件及金融購併法規探討,它突顯出台灣在金融合併處理上是保守的。 / / The M&A of Taishin Holdings Cooperation (THC) and Chang Hwa Bank (CHB) could be regarded as the first M&A (Merge and Acquisition) by LBO ( Leverage Buy-out) in Taiwan. This study, by analyzing this case, discusses the purpose, the funding source of THC and the issues after shares-exchange, which indicates the feasible methods for the release of the state holdings and the combination of the financial institutes in the future.
The beginning of this study discusses the theory and the structure of LBO to analyze the financial policy and M&A environment in Taiwan at present, including practical M&A cases and legal problems etc., which reveals not very aggressive. /
|
Page generated in 0.0499 seconds