Indiana University-Purdue University Indianapolis (IUPUI) / Our connections to the digital world are invoked by brands, but the intersection of branding and interaction design is still an under-investigated area. Particularly, current websites are designed not only to support essential user tasks, but also to communicate an institution's intended brand values and traits. What we do not yet know, however, is which design factors affect which aspect of a brand. To demystify this issue, three sub-projects were conducted. The first project developed a systematic approach for evaluating the branding effectiveness of content-intensive websites (BREW). BREW gauges users' brand perceptions on four well-known branding constructs: brand as product, brand as organization, user image, and brand as person. It also provides rich guidelines for eBranding researchers in regard to planning and executing a user study and making improvement recommendations based on the study results. The second project offered a standardized perceived usability questionnaire entitled DEEP (design-oriented evaluation of perceived web usability). DEEP captures the perceived website usability on five design-oriented dimensions: content, information architecture, navigation, layout consistency, and visual guidance. While existing questionnaires assess more holistic concepts, such as ease-of-use and learnability, DEEP can more transparently reveal where the problem actually lies. Moreover, DEEP suggests that the two most critical and reliable usability dimensions are interface consistency and visual guidance. Capitalizing on the BREW approach and the findings from DEEP, a controlled experiment (N=261) was conducted by manipulating interface consistency and visual guidance of an anonymized university website to see how these variables may affect the university's image. Unexpectedly, consistency did not significantly predict brand image, while the effect of visual guidance on brand perception showed a remarkable gender difference. When visual guidance was significantly worsened, females became much less satisfied with the university in terms of brand as product (e.g., teaching and research quality) and user image (e.g., students' characteristics). In contrast, males' perceptions of the university's brand image stayed the same in most circumstances. The reason for this gender difference was revealed through a further path analysis and a follow-up interview, which inspired new research directions to unpack even more the nexus between branding and interaction design.

Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.

The User Experience (UX) has become a major concern for the design of consumer products. Today exist various tools for the evaluation of static properties of final products on their User Experience value. However, very few tools and methods are available that allow anticipating the future User Experience during the first stages of product conception. This thesis explores the wide range of design dimensions that potentially form the experience of the user. Dynamic product properties emerge as an important factor for User Experience. In the studies a software based on inspiration words and links, as well as the technique body storming are tested as a new means of User Experience generation. The produced early concepts and interaction gestures are then evaluated through a combination of questionnaires, behavioural and physiological measurements. The study results show firstly that a wide range of design dimension needs to be regarded to design for User Experience, secondly that it is possible to apply UX evaluations on early concepts and thirdly that UX evaluations can also be done on dynamic properties like interaction gestures. This thesis furthermore contributes design research and practice with a new model on the mechanism of User Experience and a list of design dimensions for early product conception.

Στόχος της παρούσης διπλωματικής εργασίας είναι η διερεύνηση καταλληλότητας της μεθόδου πολυδιάστατης σταδιακής ανάλυσης για την αξιολόγηση σχεδιασμού ιστοσελίδων. Για την επίτευξη του στόχου, αναπτύχθηκε διαδικτυακή εφαρμογή αξιολόγησης με χρήση μεθόδων πολυδιάστατης σταδιακής ανάλυσης και αξιολογήθηκε τόσο η μέθοδος όσο και η εφαρμογή ως προς την χρησιμότητα της στο πλαίσιο που μας ενδιαφέρει, δηλαδή την αξιολόγηση σχεδιασμού ιστοσελίδων. Η εφαρμογή εκμεταλλεύεται τα πλεονεκτήματα των ιστοσελίδων πλούσιας διαδραστικότητας για την πλήρη υποστήριξη της διαδικασίας αξιολόγησης. / -

L'expérience de l'utilisateur (UX) est devenue une préoccupation majeure pour la conception de produits. Aujourd'hui, il existe différents outils pour l'évaluation de l'expérience de l'utilisateur sur l'apparence des produits finaux. Très peu d'outils et de méthodes permettant d'anticiper l'expérience de l'utilisateur au cours de la conception amont existent. Cette thèse explore le large éventail de dimensions en conception qui constituent potentiellement l'expérience de l'utilisateur. Les propriétés dynamiques des produits apparaissent comme un facteur important. Dans les expérimentations, un logiciel basé sur des mots et des liens d'inspiration, ainsi que la technique ‘body storming' sont testés comme un moyen de génération de l'expérience utilisateur. Les concepts et les gestes d'interaction produits sont ensuite évalués par une combinaison de questionnaires et de mesures comportementales et physiologiques. Les résultats des expérimentations montrent premièrement qu'une large gamme de dimensions de conception doit être considérée dès la conception amont, deuxièmement qu'il est possible d'appliquer les évaluations UX sur les premiers concepts et troisièmement que les évaluations UX peuvent également être effectuées sur les propriétés dynamiques comme les gestes d'interaction. Cette thèse apporte aussi un nouveau modèle sur l'expérience de l'utilisateur et une liste de dimensions en conception pour la recherche en design et pour les designers. / The User Experience (UX) has become a major concern for the design of consumer products. Today exist various tools for the evaluation of static properties of final products on their User Experience value. However, very few tools and methods are available that allow anticipating the future User Experience during the first stages of product conception. This thesis explores the wide range of design dimensions that potentially form the experience of the user. Dynamic product properties emerge as an important factor for User Experience. In the studies a software based on inspiration words and links, as well as the technique body storming are tested as a new means of User Experience generation. The produced early concepts and interaction gestures are then evaluated through a combination of questionnaires, behavioural and physiological measurements. The study results show firstly that a wide range of design dimension needs to be regarded to design for User Experience, secondly that it is possible to apply UX evaluations on early concepts and thirdly that UX evaluations can also be done on dynamic properties like interaction gestures. This thesis furthermore contributes design research and practice with a new model on the mechanism of User Experience and a list of design dimensions for early product conception.

This research aims to assess the causes of inefficient and unstable operation of centrifugal compressors and turboexpanders in process gas applications in order to provide a solution for performance restoration and enhancement. It encompasses thermodynamic and flow evaluations to examine the efficiency and operating range improvement options of new units. Besides, this work is complemented by a technoeconomic analysis to provide a rounded outcome from these studies. In order to achieve the desired objectives, a novel integrated approach has been developed to assess the design and performance of multi-stage centrifugal compressors. The proposed systematic methodology involves five basic elements including evaluation of compressor selection, compressor sizing and casing structure, performance prediction at the design and off-design conditions, modelling of efficiency and head deterioration causes; and stage design evaluation. This will contribute towards evaluating the geometrical parameters of the new units’ designs at the early preliminary design phase, and thus, will be useful to identify the options for efficiency and operating range enhancements. For installed units, this approach can be implemented to assess the cause of inefficient and unstable operation by assessing the available operation data. A method was developed to predict the performance curve of multi-stage centrifugal compressor based on a stage stacking technique. This approach considers the advantages of Lüdtke and Casey-Robinson methods with an incorporation of a methodology for compressor selection and sizing to generate more accurate results. To emphasize the validity of the developed model, it has been evaluated for both low and high flow coefficient applications. The obtained results show a significant improvement in the estimated efficiency, pressure ratio, shaft power and operating range as compared with the existing methods. The centrifugal compressor is designed to run under various operating conditions and different gas compositions with the primary objective of high efficiency and reliability. Therefore, a new iterative method has been developed to predict the equivalent compressor performance at off-design conditions. This technique uses the performance parameters at design conditions as a reference point to derive the corresponding performance characteristics at numerous suction conditions with less dependency on the geometrical features. Through a case study on a gas transport centrifugal compressor, it was found that the developed approach can be applied for design evaluation on the expected variation of working conditions, and for the operation diagnosis of installed units as well. Furthermore, a parametric study has been conducted to investigate the effect of gas properties on the stage efficiency, surge margin, and compressor structure. The obtained results support the need for considering the gas properties variation when the off-design performance is derived. To evaluate the impact of internal blockage on the performance parameters, this study proposed an approach to model the effect of non-reactive deposits, which has been qualified using four operation cases and the obtained results are compared with the internal inspection findings from the stage overhauling process. This also covers the influential aspects of flow blockage on the technical and economic values. Since the main challenge here is to analyze the process gas composition in real time, the influences of the non-reactive deposits have been compared with the effect of the unanticipated gas composition change. Subsequently, it has turned out that the pressureratio parameter is not enough to assess the possibility of flow blockage and unexpected gas properties change. Moreover, it was observed that the stage discharge pressure was more sensitive to the fouled aftercooler comparing with suction and internal blockage. However, the effect of contaminated aftercooler on the surge point and discharge pressure and temperature of the upstream stage was found greater than its impact on the shaft power. Thus, a substantial surge margin reduction was detected when the first stage was operating with a fouled aftercooler comparing with the measured reduction as a result of unanticipated gas properties change. Furthermore, a larger pressure ratio drop was measured in the case of liquid carryover which revealed a more significant impact of the two phases densities difference comparing with the gas volume fraction (GVF) effect. The possibility of hydrate formation has been assessed using hydrate formation temperature (HFT) criteria. Additionally, this research highlights a number of challenges facing the selection of typical centrifugal stage design by assessing the contribution of design characteristics on the operating efficiency and stable flow range. Besides, an empirical-based-model was established to select the optimum impeller and diffuser configurations in order to make a compromise decision based on technical and economic perspective. It was concluded that there is no absolute answer to the question of optimum rotor and stator configuration. The preliminary aerothermodynamic evaluation exposed that the selection of the optimum impeller structure is governed by several variables: stage efficiency, pressure loss coefficient, manufacturing cost, required power cost, resonance frequency and stable operating range. Hence, an evaluation is required to compromise between these parameters to ensure better performance. Furthermore, it was argued throughout this study that the decision-making process of the typical stage geometrical features has to be based upon the long-term economic performance optimization. Thus, for higher long-term economic performance, it is not sufficient to select the characteristics of the impeller and diffuser geometry based on the low manufacturing cost or efficiency improvement criterion only. For turboexpanders, a simple and low cost tool has been developed to determine the optimum turboexpander characteristics by analysing the generated design alternatives. This approach was used in designing a turboexpander for hydrocarbon liquefaction process. Moreover, since the turboexpanders are expected to run continuously at severe gas conditions, the performance of the selected turboexpander was evaluated at different inlet flow rates and gas temperatures. It has turned out that designing a turboexpander with the maximum isentropic efficiency is not always possible due to the limitations of the aerodynamic parameters for each component. Therefore, it is necessary to assess the stage geometrical features prior the construction process to compromise between the high capital cost and the high energetic efficiency.

This thesis begins by underlining the current methods and procedures in design evaluation as well as how design aesthetics is generally assessed. Then, it suggests the revision of current web design evaluation practices. The thesis explores a new method of incorporating Löwgren’s aesthetics of interaction attributes to help facilitate more eventful conversations within inter- and cross-departmental discussions, with the belief that such a process will manifest into more favorable design results and prevent friction during collaborative work due to incompatibility in technical jargon.

Combining products and services into Product-Service Systems (PSS), which are often owned and even operated by the company offering them, is seen as an important element of conducting more sustainable business. The prospective environmental benefits of PSS lie mainly in the improved resource- and operational efficiency. This is achieved by way of a critical shift in incentive structure: If an industrial company assumes responsibility for an offering throughout the lifecycle, the terms on which that company operates are changed substantially in comparison to traditional product sales. Instead of benefiting from a short lifetime through additional sales opportunities or making profit through the sale of spare parts, in highly integrated PSS, each parts exchange, each technicians’ visit and each day the lifetime of the offering is reduced directly affects the bottom line of the provider. Due to that, solely as a result of economic rationality, a provider of these offerings has an incentive to design in such a way that the life of this offering is prolonged, need for spare parts is reduced, service activities are facilitated and simplified, and that the conditions are in place to allow for a second or third life of the offering through remanufacturing. Regardless of this compelling logic, at times, industrial companies fail to establish the preconditions to capturing these benefits as they continue to rely on product and sales-centric design processes even though they provide PSS. This thesis aims to examine this unexploited opportunity from two vantage points. On the one hand, methods conceived in academia to support industry in implementing and executing joint, lifecycle-focused design of products and services, and the use of these methods in practice, are examined. Here, the focus firstly lies on understanding how PSS are designed today, and secondly, on what should change about PSS design methods to improve their implementability and usability in industrial practice, so that they can fulfill their supposed role as facilitators of efficient PSS design and operation. On the other hand, the possible benefits of providing specifically designed and lifecycle-focused PSS as an industrial company are in focus. To this end, the value attained by providers throughout the use phase of PSS is investigated, to then identify possible approaches towards enhancing this value. Eventually, both focus-areas are joined in an effort to examine the interaction between method-supported, lifecycle-oriented PSS design and the value attained by providers of such offerings. As a result of the research, a lacking adaptation of design processes to PSS is identified in the case companies. Further, shortcomings of PSS design methods conceived in academia, e.g. excessive complexity, lacking clarity and rigidity, are found in both literature as well as in a study with an industrial company. To take a first step towards rectifying this issue, six characteristics intended to enhance implementability and usability of PSS design methods, are presented. The value attained by PSS providers has been found to be a complex but important subject. In a case study, value determinants of high relevance to the use phase of the lifecycle have been identified and assessed for their utility as indicators in the evaluation and enhancement of PSS offerings in the design phase. The practitioners involved were supportive of the applicability of the systematic approach presented to capture more value through offering PSS. In joining both the value- and method-oriented approach, the mutual dependency of both aspects is discussed. In order to provide PSS in an economically and environmentally efficient fashion, adapting the existing design processes is imperative. The value attained by the provider can, complementary to existing customer-centric approaches, serve as an important goal for the adaptation of design processes. Ultimately, through understanding the change in incentive structure at the core of PSS, and through implementing a value-driven design process supported by efficient and effective methods aimed at providing both customer value and capturing provider benefits throughout the lifecycle, there is a genuine potential of conducting more sustainable business.

Indiana University-Purdue University Indianapolis (IUPUI) / This thesis proposes two new topologies for Uninterrupted Power Supply (UPS), and a grid-tie microinverter. The first topic will discuss an on-line transformerless UPS system based on the integrated power electronics converters that is able to control the input power factor, charge the battery, and guarantee backup operation of the system. The main advantages of the proposed UPS are active power factor correction (PFC) without the need of a complex control scheme, and integrated functions of the battery charger circuit and PFC with only three power switches. Operation modes of the system and the PWM strategy is presented in detail. The second topic discussed is of a proposed circuitry for a single-phase back-to-back converter for UPS applications. The main advantages of this topology is higher number of levels at the rectifier side, less number of power switches, and no need for a boost inductor at the input side of the converter. The last topic discussed is of a proposed patent pending microinverter. This topic was a project funded by the National Science Foundation, and its aim was to help commercialize the research. This project proposes a solution for a solar inverter called Delta Microinverter that allows easier and faster installation as well as power conversion with higher efficiency. Delta Microinverters innovation is found in its patent-pending shape and in its patent-pending circuitry, i.e., electronics mounted inside of the Delta Microinverter. The Delta Microinverters shape has a housing configured for rapid mounting using a single fastener and its power electronics configuration offers an optimized relationship between the number of levels and number of power switches.

This study aims to design and implement a domain-specific computer programming language: the Building Environment Rule and Analysis (BERA) Language. As a result of the growing area of Building Information Modeling (BIM), there has been a need to develop highly customized domain-specific programming languages for handling issues in building models in the architecture, engineering and construction (AEC) industry. The BERA Language attempts to deal with building information models in an intuitive way in order to define and analyze rules in design stages. The application of the BERA Language aims to provide efficiency in defining, analyzing and checking rules. Specific example applications implemented in this dissertation are on the evaluation of two key aspects: building circulation and spatial programming. The objective of this study is to accomplish an effectiveness and ease of use without precise knowledge of general-purpose languages that are conventionally used in BIM software development. To achieve the goal, this study proposes an abstraction of the universe of discourse - it is the BERA Object Model (BOM). It is a human-centered abstraction of complex state of building models rather than the computation-oriented abstraction. By using BOM, users can enjoy the ease of use and portability of BIM data, rather than complex and platform-dependent data structures. This study also has reviewed and demonstrated its potential for extensibility of BOM. Not only its lateral extensions such as structural building elements, but also the vertical extensions such as additional properties for existing BOM objects are good examples. In current BERA Language Tool, many computed and derived properties/relations have been proposed and implemented, as well as some basic data directly from the given building model. Target users of the BERA Language are domain experts such as architects, designers, reviewers, owners, managers, students, etc., rather than BIM software developers. It means that the people who are interested in the building environment rule and analysis are the potential users. The BERA Language Tool comprises many libraries to alleviate common but unnecessary problems and limitations that are encountered when users attempt to analyze and evaluate building models using commercially available tools. Combined with other libraries which populate rich and domain-specific datasets for certain purposes, the BERA Language will be fairly versatile to define rules and analyze various building environmental conditions.