Integration of Process Design, Scheduling, and Control Via Model Based Multiparametric Programming

The conventional approach to assess the multiscale operational activities sequentially often leads to suboptimal solutions and even interruptions in the manufacturing process due to the inherent differences in the objectives of the individual constituent problems. In this work, integration of the traditionally isolated process design, scheduling, and control problems is investigated by introducing a multiparametric programming-based framework, where all decision layers are based on a single high fidelity model. The overall problem is dissected into two constituent parts, namely (i) design and control, and (ii) scheduling and control problems. The proposed framework was first assessed on these constituent subproblems, followed by the implementation on the overall problem. The fundamental steps of the framework consists of (i) developing design dependent offline control and scheduling strategies, and (ii) exact implementation of these offline rolling horizon strategies in a mixed-integer dynamic optimization problem for the optimal design. The design dependence of the offline operational strategies allows for the integrated problem to consider the design, scheduling, and control problems simultaneously. The proposed framework is showcased on (i) a binary distillation column for the separation of toluene and benzene, (ii) a system of two continuous stirred tank reactor, (iii) a small residential heat and power network, and (iv) two batch reactor systems. Furthermore, a novel algorithm for large scale multiparametric programming problems is proposed to solve the classes of problems frequently encountered as a result of the integration of rolling horizon strategies

A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems

We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it. In our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure

Çok değişkenli kalite kontrolunda maliyet analizi

Tez (doktora) - Anadolu ÜniversitesiAnadolu Üniversitesi, Sosyal Bilimler Enstitüsü, İşletme Anabilim DalıKayıt no: 6818Çalışma öncelikle, kalite ve kalite kontrolüne ilişkin kavramlar, gelişim süreci, genel çizgileriyle bazı kontrol grafikleri ile birlikte kalite kontrolunun işletmeye olan katkıları incelenmiştir. İşletmenin kalite kontrolu durumunda katlanacağı maliyetler ve bunların bir model çerçevesinde incelenmesinin gereği belirtilerek, çalışmada uygulanacak Montgomery-Klatt maliyet modeli tanıtılmıştır. Montgomery-Klatt modelinin uygulaması modelin parametrelerinin belirlenmesi açıklanmıştır. Ele alınan ürünün üç kalite özelliği gözönüne alınarak geliştirilen bilgisayar programları yardımıyla modelin çözümü ve seçilen bazı parametrelere göre gerçekleştirilen duyarlılık analizleri verilmiştir. Çok değişkenli kalite kontrolunda, Montgomery-Klatt maliyet modelinin üç kalite özelliğine uygulanması ve bağlı olarak yapılabilecek çalışmalar sonuçta tartışılmıştır