Workflow is a collection of tasks organized to accomplish some business process. It also defines the order of task invocation or conditions under which task must be invoked, task synchronization, and information flow. Before the execution of the workflow, a correct execution schema, in other words, the schedule of the workflow, must be determined. Workflow scheduling is finding an execution sequence of tasks that obeys the business logic of workflow. Research on specification and scheduling of workflows has concentrated on temporal and causality constraints, which specify existence and order dependencies among tasks. However, another set of constraints that specify resource allocation is also equally important. The resources in a workflow environment are agents such as person, machine, software, etc. that execute the task. Execution of a task has a cost and this may vary depending on the resources allocated in order to execute that task. Resource allocation constraints define restrictions on how to allocate resources, and scheduling under resource allocation constraints provide proper resource allocation to tasks. In this thesis, we present two approaches to specify and schedule workflows under resource allocation constraints as well as temporal and causality constraints. In the first approach, we present an architecture whose core and novel parts are a specifi- cation language with the ability to express resources and resource allocation constraints and a scheduler module that contains a constraint solver in order to find correct resource assignments. In the second approach, we developed a new logical formalism, called Concurrent Constraint Transaction Logic (CCTR) which integrates constraint logic programming (CLP) and Concurrent Transaction Logic, and a logic-based work- flow scheduler that is based on this new formalism. CCTR has the constructs to specify resource allocation constraints as well as workflows and it provides semantics for these specifications so that validity of a schedule can be checked.

In this work, we present a new method for seismic waveform characterization, which is aimed at extracting detailed litho-stratigraphical information from seismic data. We attempt to estimate the lithological attributes from seismic data according to our parametric representation of stratigraphical horizons, where the parameter values provide us with a direct link to nature of lithological transitions. We test our method on a seismic dataset with a strong diagenetic transition (opal-A to opal-CT transition). Given some information from cutting samples of well, we use a percolation-based model to construct the elastic profile of lithological transitions. Our goal is to match parametric representation for the diagenetic transition in both real data and synthetic data given by these elastic profiles. This match may be interpreted as a well-seismic tie, which reveals lithological information about stratigraphical horizons.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, Sept. 2004. / Thesis advisor(s): George W. Dinolt. Includes bibliographical references (p. 133-136). Also available online.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 269-285). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 269-285). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 154-165).

Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2007. / Bauchau, Olivier, Committee Member ; Hodges, Dewey, Committee Chair ; Singhose, William, Committee Member ; Costello, Mark, Committee Member ; Flannery, Raymond, Committee Member.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Small, medium and micro enterprises are important contributors to the economic and socioeconomic development of South Africa. However, most enterprises struggle to become established. The high rate of failure is due to a lack of access to finance, poor managerial and technical skills, and also the competitive business environment. The focus of this research report is on the development of a continuous and sustainable internal process improvement roadmap that provides skill constrained small business managers with strategic and technical support, in order to make their organisations more competitive in the current business environment, without expensive consultation. The first step toward the development of the roadmap is discussed as a ten step basic process improvement cycle, based on an interpretation of the PDCA cycle. These ten steps provide most of the methods that are needed for practical implementation of improvement activities. However, this approach needs strategic support in order to ensure that improvement activities focus on the critical improvement opportunities. The second step regards the identification of strategic support, and additional improvement methods, to align improvement activities toward the critical improvement opportunities, which represent a common goal. Three methodologies are discussed as individual roadmaps to determine the crucial aspects that can be integrated into a holistic management roadmap, which accommodates practical improvement. These methodologies are lean thinking, theory of constraints, and the six sigma philosophy. The final roadmap is then developed, based on the principle that perspectives can be used to develop the perception of people toward improvement. Different perspectives are identified from the studied improvement methodologies, and the execution of improvement activities is then supported with the basic process improvement cycle. The perspectives are categorised into three main perspectives. First, the organisational perspective provides an overview of the philosophy, people, and process. Second, the primary process perspective provides an overview of the critical process aspects; value, throughput, and quality. Third, the secondary process perspective connects these critical process aspects in terms of effectiveness, agility, and efficiency. The roadmap is then completed when management can transcend above perspective. / AFRIKAANSE OPSOMMING: Klein, medium en mikro ondernemings is belangrike bydraers tot die ekonomiese en sosio-ekonomiese ontwikkeling van Suid-Afrika. Meeste ondernemings sukkel egter om gevestig te raak. Die hoë koers van mislukking is weens ‘n gebrek aan finansiële toegang, swak bestuurs en tegniese vaardighede, en die mededingende sake-omgewing. Die fokus van hierdie navorsingsverslag is op die onwikkeling van ‘n deurlopende en volhoubare interne proses verbeterings padkaart wat klein besigheid bestuurders verskaf met strategiese en tegniese ondersteuning, sonder duur konsultasie, ten einde hul organisasies meer mededingend the maak in die huidige sake-omgewing. Die eerste stap vir die onwikkeling van die padkaart word bespreek as ‘n tien stap basiese verbetering siklus, gebaseer op ‘n intrepretasie van die PDCA siklus. Hierdie stappe voorsien meeste van die metodes wat nodig is vir praktiese implementering van verbetering aktiwiteite. Die benadering moet egter strategies ondersteun word om te verseker dat verbetering aktiwiteite op die kritieke verbeterings geleenthede fokus. Die tweede stap word bespreek vir die identifisering van strategiese ondersteuning, asook addisionele verbetering metodes, om verbetering aktiwiteite in lyn te bring met kritiese verbeterings geleenthede, wat ‘n gemeenskaplike doel verteenwoordig. Drie metodieke word bespreek as individuele padkaarte om die deurslaggewende aspekte te bepaal wat geïntegreer kan word in ‘n bestuurs padkaart, wat praktiese verbetering akkomodeer. Die metodieke is “lean thinking”, “theory of constraints”, en “six sigma”. Die finale padkaart word dan ontwikkel, gebasseer op die beginsel dat perspektiewe gebruik kan word om mense se persepsie van verbetering te ontwikkel. Verskillende perspektiewe is geïndentifiseer vanuit die verbetering metodieke, en die uitvoering van verbeterings aktiwiteite word dan ondersteun met die basiese verbeterings siklus. Die perspektiewe is ingedeel in drie hoof perspektiewe. Eerste, die organisatoriese perspektief verskaf ‘n hoë vlak oorsig van die filosofie, mense, en proses. Tweede, die primêre proses perspektief verskaf ‘n oorsig van die kritiese proses aspekte; waarde, deurset, en kwaliteit. Derde, die sekondêre proses perspektief verbind die proses aspekte in terme van effektiwiteit, aanpasbaarheid, en doeltreffendheid. Die padkaart word dan eindelik voltooi wanneer die bestuur perspektief te bowe kan kom.

Essa tese investiga três problemas: (1) o uso de dados de diferente suporte em geoestatística, (2) simulação multivariada com restrições e (3) verificação da distribuição multivariada. Quando as amostras tem suporte diferente, essa diferença de suporte precisa ser considerada para construir um modelo de teores. A tese propõe a krigagem utilizando covariâncias médias entre as amostras para considerar dados de diferente suporte. A metodologia é comparada com dois métodos: (1) krigagem utilizando covariâncias pontuais entre os dados e (2) o método indireto. A krigagem utilizando covariâncias pontuais entre os dados ignora a diferença de suporte entre os dados. O método indireto trabalha com a variável acumulação, em vez do teor original. A krigagem com covariâncias médias resultou em estimativas mais precisas do que os outros dois métodos. Depósitos minerais multivariados frequentemente têm variáveis que contém restrições de fração e soma. As restrições de fração ocorrem quando uma variável é parte da outra, como a Alumina Aproveitável e Alumina Total em um depósito de bauxita. A Alumina Aproveitável não pode ser maior do que a Alumina Total. Restrições de soma ocorrem quando a soma das variáveis não pode exceder um valor crítico. Por exemplo, a soma de teores não pode ser maior do que cem. A tese desenvolve uma metodologia para cosimular teores com restrições de soma e fração. As simulações reproduzem os histograms, variogramas e relações multivariadas e honram as restrições de soma e fração. As simulações geoestatísticas multivariadas devem reproduzir as relações entre as variáveis. Dentro desse contexto, essa tese investiga a verificação da distribuição multivariada de simulações geoestatísticas. A tese desenvolve uma métrica de distância entre a distribuição multivariada dos dados e das simulações. A métrica desenvolvida foi efetiva para detectar erro e viés. Além disso, a métrica foi usada para comparar métodos de simulação geoestatística multivariada. / This thesis investigates three problems: (1) use of data of different support in geostatistics, (2) multivariate simulation with constraints and (3) verification of the multivariate distribution. When the samples have different support, this difference in support must be considered to build a grade model. The thesis proposes kriging with average covariances between the data to consider data of different support. The methodology is compared with two methods: (1) kriging using point support covariances between the data and (2) the indirect approach. Kriging using point support covariances between the data ignores the difference in support between the data. The indirect approach works with the variable accumulation, instead of the original grade. Kriging with average covariances resulted in more precise estimates than the other two methods. Multivariate mineral deposits often have variables that contain fraction and sum constraints. Fraction constraints occur when a variable is a fraction of the other, such as Recoverable and Total Alumina in a bauxite deposit. The Recoverable Alumina must not exceed Total Alumina. Sum constraints occur when the sum of the variables must not exceed a critical threshold. For instance, the sum of grades must not be above one hundred in a mineral deposit. The thesis develops a methodology to cosimulate grades with sum and fraction constraints. The simulations reproduce the histograms, variograms and multivariate relationships and honor the sum and fraction constraints. Multivariate geostatistical simulations should reproduce the relationships between the variables. In this context, the thesis investigates the verification of the multivariate distribution of geostatistical simulations. The thesis develops a metric to measure the distance between the multivariate distributions of the data and the simulations. The metric developed was effective to detect error and bias. Moreover, the metric was used to compare multivariate simulation methods.