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In industrial production processes, control charts have been developed to detect changes in the parameters specifying the quality of the production so that some rectifying action can be taken to restore the parameters to satisfactory values. Examples of the control charts are the Shewhart chart and the cumulative sum control chart (CUSUM chart). In designing a control chart, the exact distribution of the observations, e.g. normal distribution, is usually assumed to be known. But, when there is not sufficient information in determining the distribution, nonparametric procedures are appropriate. In such cases, the control value for the parameter may not be given because of insufficient information. To construct a control chart when the control value is not given, a standard sample must be obtained when the process is known to be under control so that the quality of the product can be maintained at the same level as that of the standard sample. For this purpose, samples of fixed size are observed sequentially, and at each time a sample is observed a two-sample nonparametric statistic is obtained from the standard sample and the sequentially observed sample. With these sequentially obtained statistics, the usual process control procedure can be done. The truncation point is applied to denote the finite run length or the time at which sufficient information about the distribution of the observations and/or the control value is obtained so that the procedure may be switched to a parametric procedure or a nonparametric procedure with a control value. To lessen the difficulties in the dependent structure of the statistics we use the fact that conditioned on the standard sample the statistics are i.i.d. random variables. Upper and lower bounds of the run length distribution are obtained for the Shewhart chart. A Brownian motion process is used to approximate the discrete time process of the CUSUM chart. The exact run length distribution of the approximated CUSUM chart is derived by using the inverse Laplace transform. Applying an appropriate correction to the boundary improves the approximation. / Ph. D.

An important process-design problem in multicomponent separations is separation sequencing, which is concerned with the selection of the best method and sequence for a separation system. Essentially all of the published work on this subject has been limited to high-recovery or sharp separations, in which each component to be separated appears in one and only one product stream. In industrial practice, however, it is often useful to permit components that are being separated to appear in two or more product streams. This type of separation results in products that have overlapping components and is called nonsharp or sloppy separations. The present work proposes and demonstrates a simple and practical approach to the systematic synthesis of sloppy multicomponent separation sequences. The task of synthesizing sloppy multicomponent separation sequences is inherently more complicated than that of synthesizing sharp separation sequences as identification of infeasible splits and stream splitting, and transformation of infeasible product sets into equivalent feasible product sets are examples of some difficult tasks involved. A successful synthesis strategy calls for the development of an effective and flexible framework for representing the synthesis problem and for analyzing the feasibility of component splits. In this thesis, we propose a "component assignment diagram (CAD)" for problem representation. It is shown that the use of a CAD allows the design engineer to consider many alternative solutions (or sequences) and eliminate all infeasible component splits. Further, a "separation specification table (SST)" is proposed for feasibility analysis. In particular, the use of an SST provides a means to : (i) properly define and specify key and nonkey components; (ii) quickly identify feasible and infeasible splits; (iii) effectively deal with fuel products with unmatched compo- nent specifications; and (iv) systematically consider sloppy separations with multiple split points. One difficult problem arising from the design of multicomponent distillation columns for sloppy separations is to appropriately specify the distributions of non-key components in both overhead and bottoms products. Despite the importance of these specifications, there is very little information available on this subject in the literature. This thesis reports the results from a comparative study of rigorous simulation and shortcut modeling of multicomponent distillation columns for sloppy separations. One objective was to obtain improved quantitative understanding and practical design insights into the characteristics of nonkey distributions through a shortcut modeling based upon the Fenske equation. One method proposed in this work for synthesizing sloppy multicomponent products is a heuristic method that involves a two-phase approach. The first phase is concerned with the feasibility analysis of splits pertinent to a CAD with the aid of an SST. The second phase is to specify systematically a subsequent split by applying heuristics, an activity that involves the sequential application of several "rank-ordered" heuristics. A unifying approach is proposed and demonstrated for the synthesis of sloppy multicomponent product sets. Its objective is to generate equally good initial separation schemes, featuring as many as three characteristically different sequences, including all-sharp, all-sloppy, and both sharp and sloppy (i.e., mixed separation). The proposed methods have been applied to a number of industrial separation problems. The results show that the new methods offer an extremely useful means for design engineers to generate a number of good initial sequences for obtaining sloppy multicomponent product sets prior to the ultimate separator optimization and heat integration. / Ph. D.

No / Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting β-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488–1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectro-scopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control.

No / Produttion control methods allow factory produced mortars to be supplied to a more consistent formulation than site produced mortars. However, there is scope to enhance their "sustainability" credentials by addressing the methods of drying the wet sand and the use of lower energy hydraulic components. This paper describes the development of a technique in which quicklime is added in controlled quantities to remove free water by both chemical combination and evaporation. The slaked lime so generated is porous and a third mechanism of absorption is suggested which, however, might have adverse effects during storage of the pre-blended mortar. The principal process-control factors are lime addition based upon a ratio of the stoichiometric requirements for complete slaking of the quicklime, free moisture content of the sand, mixing time of the combined sand and quicklime, and storage of the mixed material. (C) 2015 Elsevier Ltd. All rights reserved.

The process control domain is intrinsically complex and dynamic. It has proved to be difficult to construct and maintain process control systems under the traditional software development methodologies. Object Orientation is the latest paradigm in software development. The reason for its widespread acceptance is that it allows the application of the principles of hierarchical structuring and component abstraction which is essential in building large systems. It also promotes component reusability which makes systems easier to maintain and modify. For the process control domain, these are important benefits. Furthermore, most process control systems have physical devices which can be modeled naturally as objects with the timing and performance issues of each object directly addressed. A Target System Reference Model which addresses various aspects of the process control domain is proposed within this dissertation. The objective is to provide a frame of reference within which a process control system can function. / Computing / M. Sc. (Computer Science)

The purpose of this thesis is to develop a method of systematic visualization for coordinate measurements at Saab Aerostructures. The thesis begins with mapping the coordinate measuring process. After that, it is proposed to define key measurement points through quality standards as this will simplify the visualization of the measurements with a control chart through a Visual Management-system.  To stay in the forefront of the market and keep the relations with current customers, Saab wants to increase the quality of their products by reducing the amount of measurement deviations. The measurements are currently scarcely visualized to the employees. This is because of the complicated method which currently is being used to reflect which measurements that are deviating. The process of visualization should be definite and simple to use as this will lead to less deviations. Furthermore, it will contribute to continuous improvement for the process of measuring.  The methods used in this thesis include semi structured interviews, observations and studies of internal documents. These methods are then triangulated to be able to map the process in detail. However, no employees knew either the coordinate measuring process or the visualizing process by heart. This led to the author having to proceed with a Process Walk. The method helped map both the processes and through this, problems were identified in the process which would otherwise hinder the visualization of measurements. Moreover, a literature study was conducted of Quality Management Systems as these outline criteria for Saabs products. Visual Management-system was also studied with the likes of information boards as this fit Saab with their previous prerequisites of information boards.  From the mapping of today’s process, problems were identified that would hinder them from systematically visualize their coordinate measuring process. From the problems that were outlined, improvement suggestions were proposed. Firstly, it was conducted that too much data is hindering the transparency of the process. From Quality Standards it is proposed to clearly define key measurements points and document these. This is done through the means of a SIPOC and a FMEA. Furthermore, it is proposed to analyze which measurement data is to be saved as a major part of the data consists of irrelevant information. As the process of visualizing the coordinate measuring process was timed to 90 hours it was also proposed to clarify templates which systematically exports and sorts data in an Excel-format with the use of Saabs ERP-system, instead of converting from XML which is done today. These templates can then immediately be used by Excel to visualize the outcome of the coordinate measurements with the help of a Visual Management-system. The system makes use of bar diagrams to highlight which processes that are producing most deviations. The processes outcome is visualized in a control chart which enhances how the variation of the process is affecting the measurement outcome. The last improvement suggestion states that Saab should use the control chart as a way of stabilizing their processes as this will lead to qualitative processes where capability can be proven to their customers. / Syftet med detta arbete är att utveckla ett arbetssätt för systematisk visualisering av mätutfallet vid koordinatmätning på Saab Aerostructures. Arbetet lägger sin grund i en kartläggning av koordinat-mätningsprocessen för att sedan föreslå att utefter rådande kvalitetsstandarder tydligt definiera nyckelmått som skall förenkla visualisering av mätutfallet med styrdiagram i ett Visual Management-system.  För att Saab ska ligga i framkant av marknaden och behålla de kundrelationer man har ska man öka kvaliteten på produkter genom att minska antalet anmärkningar. Mätutfallet och dess anmärkningar är föga visualiserade för anställda då en komplicerad process krävs för att återspegla vilka mätpositioner som skapar problem. Om processen för visualisering blir konkret och enkel att använda kommer det att bidra till färre anmärkningar och kontinuerlig förbättring av kontrollmätningsprocessen.  Metoder som användes för arbetet inkluderar halvstrukturerade intervjuer, observationer och studier av interna dokument. Dessa metoder trianguleras sedan för att detaljerat kartlägga processen men på grund av att inte tillräckligt många kunde beskriva kontrollmätnings- eller visualiseringsprocessen genomfördes en ytterligare metod, en Process walk. Metoden hjälpte att detaljerat kartlägga kontrollmätnings-processen och dess nuvarande visualiseringsmetod. Från kartläggningen identifierades problem och barriärer för visualisering av data vilka annars skulle hindra visualiseringen av mätutfallet. Utöver dessa metoder genomfördes även en litteraturstudie av Kvalitetsledningssystem då dessa svarar för kriterier för Saabs produkter. Även Visual Management-system studerades med inriktning på informationstavlor då detta passade Saabs förutsättningar med tidigare informationstavlor.   Från kartläggningen av dagens process identifierades problem och barriärer vilka hindrar Saab från att systematiskt visualisera deras kontrollmätningsprocess. Från dessa problem och barriärer utvecklades förbättringsförslag. För det första förbättringsförslaget insågs att alldeles för mycket data hindrar överblickbarheten för processen varpå förslag gavs om att utefter kvalitetsstandarder, definiera nyckelmått och dokumentera dessa för alla produkter som kontrollmäts. Definieringen genomförs med en SIPOC och en FMEA. Vidare föreslås även att se över all lagring av mätdata då data till större del innehåller oviktig information som ändå förkastas. Då processen för visualisering av kontrollmätningsprocessen visade sig ta upp mot 90 timmar föreslogs även att förtydliga mallar som systematiskt exporterar och sorterar data i xlsx-format mot Saabs ERP-system, istället för att först konvertera från XML-format. Dessa mallar används sedan av Excel för att framställa mätutfallet av koordinatmätningarna med hjälp av ett Visual Management-system. Systemet använder sig av stapeldiagram för att förtydliga vilka processer som påvisar flest anmärkningar. Processernas mätutfall visualiseras i ett styrdiagram vilket förtydligar hur variationen i processer påverkar mätutfallet. Det sista förbättringsförslaget är att Saab ska börja använda sig av styrdiagram för att stabilisera deras processer för att få kvalitativa processer där man kan påvisa duglighet för sina kunder.

The process control domain is intrinsically complex and dynamic. It has proved to be difficult to construct and maintain process control systems under the traditional software development methodologies. Object Orientation is the latest paradigm in software development. The reason for its widespread acceptance is that it allows the application of the principles of hierarchical structuring and component abstraction which is essential in building large systems. It also promotes component reusability which makes systems easier to maintain and modify. For the process control domain, these are important benefits. Furthermore, most process control systems have physical devices which can be modeled naturally as objects with the timing and performance issues of each object directly addressed. A Target System Reference Model which addresses various aspects of the process control domain is proposed within this dissertation. The objective is to provide a frame of reference within which a process control system can function. / Computing / M. Sc. (Computer Science)

Modellbasierte virtuelle Sensoren (VS) ermöglichen die Messung von qualitätsbestimmenden Prozessparametern (bzw. Hilfsregelgrößen) dort, wo eine direkte Messung zu teuer oder gar nicht möglich ist. Für die adaptiven VS, die ihr internes Prozessmodell nach Data-Driven-Methode bilden (z. B. durch die Benutzung künstlicher neuronaler Netze (KNN)), besteht das Problem der Abschätzung der Prädiktionsstabilität. Aktuelle Lösungsansätze lösen dieses Problem nur für wenige KNN-Typen und erfordern enormen Entwurfs- und Rechenaufwand. In dieser Arbeit wird eine alternative Methode vorgestellt, welche für eine breite Klasse von KNN gilt und keinen hohen Entwurfs- und Rechenaufwand erfordert. Die neue Methode wurde anhand realer Anwendungsbeispiele getestet und hat sehr gute Ergebnisse geliefert. Für die nicht adaptiven virtuellen Sensoren wurde eine aufwandsreduzierte Adaption nach Smith-Schema vorgeschlagen. Dieses Verfahren ermöglicht die Regelung totzeitbehafteter und zeitvarianter Prozesse mit VS in einem geschlossenen Regelkreis. Im Vergleich zu anderen Regelungsstrategien konnte damit vergleichbare Regelungsqualität bei einem deutlich geringeren Entwurfsaufwand erzielt werden. / Model-based virtual sensors allow the measurement of parameters critical for process quality where a direct measurement is too expensive or not at all possible. For the adaptive virtual sensors built after data-driven method (e.g., by use of an ANN model) there is a problem of the prediction stability. Current solutions attempt to solve this problem only for a few ANN types and require a very high development effort. In this dissertation a new method for the solution of this problem is suggested, which is valid for a wide class of the ANNs and requires no high development effort. The new method was tested on real application examples and has delivered very good results. For the non-adaptive virtual sensors a simple adaptation mechanism was suggested. This technique allows the control of dead-time and time-variant processes in closed loop. Besides, in comparison to other control strategies the comparable results were achieved with smaller development effort.