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Information systems become more accessible as a service offered to anybody, anywhere, at any time, via almost any device and computing platform. The continuous growth and the heterogeneity of these devices induce diverse user experiences depending on the device and challenge designers to creating methods and tools for engineering usable, yet accessible, information systems. Instead of repeating a similar development life cycle, design patterns concentrate design solutions with embedded usability and accessibility. Once a pattern is selected, the developer is responsible for adequately program the pattern code, which is a tedious and error-prone task. In order to address these challenges, this paper presents UIPLML (User Interface Pattern Language Markup Language), a XML-compliant markup language for defining user interface patterns for multiple contexts of use, e.g., for different users carrying out a task on different devices in different environments. A meta-model with new expressiveness enables multi-facet pattern matching. To validate it, four UIPLML pattern databases have been created: a base of 237 entries for multi-platform systems, a base of 42 entries for context-aware interfaces, a base of 10 entries for culturally-aware interfaces, and a base of 52 entries for accessibility. The master/detail pattern is in particular supported by a software for generative pattern-based approach where application parameters and contextual data govern automated user interface XML creation which, in turns, generates code for multi-platform information systems.

If resources are everywhere, why collaboration is not? This is especially an important question for SMEs since they have to face challenges for their survival with their limited resources. Globalization and increasing competition force smaller companies to search new ways to survive. This dissertation tries to provide elements of solution by developing three essays around the business network approach. The first essay enters the black box of business network by providing insights around international collaborations and its benefits for young internationalizing companies. The second essay builds on the international entrepreneurship literature by describing collaborations as a way for smaller companies to speed up their internationalization process. Finally, the third essay deals with the determinants of international collaboration adoption. This essay also examines the role of institutions within the business network approach of internationalization. Interviews with key public institutes and entrepreneurs suggest that collaboration has a pivotal role to play in SME internationalization, as long as the contextual factors are considered, which in turn, reduces the risks of partnerships. Through phone surveys, the study shows that network variables allow understanding why some SMEs are able to internationalize more early and rapidly than others. (ECGE - Sciences économiques et de gestion) -- UCL, 2016

The general theme covered in this dissertation is “Testing the impact of fiscal, financial, and political variables on European bond spreads”. We argue that deteriorations in fiscal and political variables during bad economic conditions and increased volatility in stock markets have been major drivers of the rise in bond spreads in various European countries. This allows us, to some extent, to apply an innovative approach when analyzing these internal factors. To the best of our knowledge, there are no existing research in the literature on European bond spreads, that apply a non-linear threshold method to explain how the impact of a change in government debt and in political risk on bond spread, depends on the level of government debt, real GDP growth, political risk, stock market volatility, and membership to the euro area. Moreover, in the literature analyzing the drivers of bond spreads, political risk variables usually considered are international political risks rather than country-specific political risks, that capture the deterioration of the domestic political situation. In the first chapter, we propose a framework that captures the impact of public debt ratios during periods of bad economic conditions. We used a fixed effect panel approach to show that deterioration of public debts are significant during bad economic conditions, in contrast to periods of normal economic conditions in euro area countries. In the second chapter, we extend the analysis by considering the state of financial systems and economic conditions. This allows us to determine endogenously and exogenously the threshold levels of public debt and volatility index. In the third chapter, we further extend our analysis to consider country-specific political risk variables. In particular, we devote much effort to determine the drivers of bond spreads in various European groups using the dynamic panel threshold methodology. (ECGE - Sciences économiques et de gestion) -- UCL, 2016

International audience; The location of a restaurant is critical to its success or failure and the impact it has on the surrounding community. Business owners and customers alike are affected by the geographical spaces selected for restaurants. With the rise of fast-food delivery, people can have their food delivered within a specific time frame. The optimization of the wait time is vital to ensuring the efficiency of operations and customer satisfaction. The first objective of our study is to ascertain the proximity between restaurants and those who live within the study area. The second objective is to then suggest locations where couriers could park to be near the maximum number of restaurants, and thus able to make deliveries in the shortest amount of time possible.

We draw on the geographical concepts of social space, territoriality, and distantiation to examine an apparent tension inherent in telework: i.e., using information and communication technologies to work away from traditional workplaces can give employees a greater sense of autonomy while simultaneously placing new constraints on the way they conduct themselves in settings that were previously beyond the reach of managerial control. We draw on a longitudinal case study of a Belgian biopharmaceutical company to show how technical and professional teleworkers developed broadly similar strategies of spatiotemporal scaling to cope with this tension. We conclude by considering how these scaling strategies allowed employees to cope with the demands of ‘hybrid’ work that is conducted both at home and in traditional settings.

If risk is everywhere, why is not assurance? This is an especially important question for boards of directors since they are often required to attest the effectiveness and appropriateness of internal control and risk management systems, but how can a board do so without receiving holistic assurance? This dissertation tries to provide elements of solution by developing four essays around the concept of combined assurance. Originally introduced by The King III Report in South Africa, combined assurance represents the coordinated assurance from all assurance providers within an organization that holistically goes to the board in order that its members fulfil their risk management duties appropriately. These duties include: the effectiveness and appropriateness of risk management, and whether significant risks are managed adequately. If a board does not understand these significant risks or does not form an adequate view of them, then a board is unable to attest that it is discharging its risk management duties. The first essay enters the black box of combined assurance by providing insights around interpretation of combined assurance, its drivers, and its benefits as experienced by several organizations having started to implement combined assurance. This essay builds on the risk management literature by describing combined assurance as a way for boards to enhance their risk management oversight duties to various stakeholders. The second essay examines the role of the internal audit function within the combined assurance approach. Interviews with key participants in the combined assurance approach suggest that the internal audit function has a pivotal role to play. The third essay explores the critical steps that an organization should follow to implement combined assurance by collecting insights from multiple case studies. It suggests a six-step approach for adequate combined assurance implementation. Finally, the fourth essay deals with the determinants of combined assurance adoption. Through an online survey instrument administered to internal auditors, the study shows that several variables allow understanding why some organizations implement combined assurance, whereas others are not. (ECGE - Sciences économiques et de gestion) -- UCL, 2015

Today, an effective adaptation of UI is the main requirement to meet end-users needs and improve the UI usability. A significant variety of interaction requirements, given mainly the heterogeneity of context, should be accommodated via an adapted UI meeting users expectations. However current adaptation approaches still considering established rules and guidelines preventing user involvement and decreasing UIs context-awareness. Thus UIs definition and contextualization requires deeper study of how to adapt efficiently with regards to ambient contexts and end-users expectations. This paper proposes a Context-awareness Model (CAM) that considers UI models and context dimensions besides supporting the adaptation specification and the users involvement. The CAM is aimed to support stakeholders for developing and conceptualizing system

The diversity of interactions flows offers a large amount of information that can contribute significantly the interaction context-awareness at runtime. Particularly, users interventions can indicate accurately user’s preferences and needs and can improve the personalization process. User’s feedback looks promising to provide knowledge and assessment for an effective adaptation performance. However, there is no any agreed terminology for gathering and assuring the full understanding of what "Feedbacks" represent for adaptation, what is the added value? what it entails and how it could be interpreted. In this paper, we propose an extensible feedbacks ontology focusing upon the multidimensional nature of feedbacks and addressing the runtime personalization process.

This research aims at examining the impact of using a gamification interface by comparison with a classical online interface in order to personalize a product. The quality of the experience that is felt by the consumer during the personalization process and behavioral patronages are studied. Findings confirm that personalizing a product through a gaming interface might have a positive impact in terms of experience during the process but also on patronage intentions. Hence this research also shows that solely adding gamification mechanisms such as challenges in a personalizing interface is not enough to significantly enhance the quality of the perceived experience.

An important challenge in Lot Sizing faces to decision makers when there are capacity constraints. Decisions related to these problems have a direct impact at the operational level of the company, and consequently, they have an effect over the global performance of the company. One of the capacity constraints in Lot Sizing Problems arises when the machines produce with variable productivity. It means that their production capacity changes over time. Moreover, when the production capacity decreases over time, it is vital to stop the production line and fix the machines to bring them back to full productivity. Thus, another problem is about the maintenance scheduling. Given that the machines do not work during the maintenance period, it is important to synchronize maintenance and Lot Sizing decisions. Taking into consideration the company’s freight, transportation decisions should be incorporated into the model as well in order to exploit the freight efficiently. The latter aspect adds to the complexity of the problem significantly. Throughout this thesis, we aim to propose an improved formulation to deal with Dynamic Productivity Lot Sizing Problem (DPLSP) by extending traditional approaches provided for the Capacitated Lot Sizing Problems (CLSPs). Many of these problems are hard and hence are unlikely to admit polynomial time solutions. Therefore, we approach DPLSP based on the already existing common sense or specialized heuristics for CLSPs. Because of the nonincreasing capacity assumption we apply in our model, it is vital to integrated the aforementioned problem with the maintenance scheduling in order to bring the machines back to their full productivity. Specifically, in this research we plan to cope with a single (multi)-product(s), single (multi)-machine(s) CLSP, as a basic production/inventory problem with decreasing capacity. Then, we plan to synchronize maintenance and transport aspects to best satisfy the demand, while minimizing the total cost of the process. We propose two types of algorithms to solve such an integrated problem. The first algorithm (off-line algorithm) is suggested when the demand is deterministic. We exploit MIP-based Fix-and-Optimize heuristic which results is compared to the results obtained using the MIP solver. The second algorithm which called online algorithm is propounded when the demand is not known in advance. The effectiveness of the proposed online algorithms is measured by their competitive ratio, defined as the ratio between the maximum number of the demands can be satisfied and that of a hypothetical offline algorithm (Dynamic Programming) which knows the entire sequence of requests in advance and chooses its actions optimally. (ECGE - Sciences économiques et de gestion) -- UCL, 2015

Although the adaptation approaches are evolving with changes in the technical landscape, their purposes are still to increase user satisfaction and result in successful interactions. Commonly, adaptation is intended to ensure context-aware interaction meeting user expectations. Thereby ‘context-awareness’ as well as ‘user-centeredness’ becomes mandatory to adapt the UI in response to context changes. However, interface adaptations are mostly managed at design time, instead of conforming current situations and the ambient-contexts. Thus, an accurate adaptation approach should be context-aware, flexible, incremental and have a crosscutting impact on software patterning, with an insignificant cost. In order to address these main shortcomings and support stakeholders to bridge the gap between adaptation goals and user needs, this proposal conveys a theoretical framework establishing runtime context-aware adaptation within an agile perspective.

Network (or graph) data analysis finds applications in many contexts, including biology, finance, marketing, and physics, to name a few. With the recent thriving of internet and social networks, these graph mining techniques have grown in popularity as an important tool to process, analyze, and make predictions from the quickly increasing amount of network data. This thesis mostly focuses on the randomized shortest path (RSP) framework, which defines a family of dissimilarities between nodes of a network that interpolates between the least cost path distance (optimal behavior) and the commute-cost distance (purely random behavior). This thesis therefore builds upon and extends this framework by proposing, among others, new dissimilarity measures, a design of biased random walk, as well as fast solutions to approximate the RSP for large graphs. It also explores various applications like node clustering, stochastic Markov decision processes, connectivity modeling in ecological landscapes, and collaborative filtering. (ECGE - Sciences économiques et de gestion) -- UCL, 2023

Technology based innovation can make traditional stores more attractive and aesthetically appealing, and thus influencing consumer’s shopping behavior (Pantano and Di Pietro; 2012; Shankar et al., 2011). These technologies (eg. Augmented reality, RFID, QR codes…) could be used to enhance the customer shopping experience in-store but also the product consumption experience (Bodhani, 2012, 2013). In this perspective and thank to three studies using three different methodologies the present research aims to understand the added value of augmented reality from consumers’ point of view in the case of toys industry. In the first study, we investigate through a survey with a sample of 115 children aged between 4 to 10 the effect of associating classic toys to augmented reality technology. The second data collection consists in a field study conducted in a toy brand flagship store with a sample of 42 children. Effects of augmented technology are compared with other digital technologies on the perception of shopping experience and shopping environment by children. Finally, a series of in- depth interviews were conducted in order to better explore expectations and reactions of adult consumers to the introduction of augmented reality technologies in toy stores. The results of these three studies confirm the relevance and the positive effect of the use of augmented reality for differentiating toys and toy stores and improving the shopping and consumption experiences.

Context-aware Adaptation (CAA) of user interfaces involves the identification of the relevant context information that surrounds the user during her interaction in order to properly adapt elements of an interactive system aiming at enhancing the end user interaction. The main goals of CAA are improving the usability levels of the system by using the relevant information of the user context to properly transform a system.In this special issue the authors are presenting various model-based approaches to user interface design and evaluation aiming to support the context aware adaptation.

The variety of contexts of use in which the interaction takes place nowadays is a challenge for both stakeholders for the development and end users for the interaction. Stakeholders either ignore the exponential amount of information coming from the context of use, adopting the inaccessible approach of one-size-fits-all, or they must dedicate a significant effort to carefully consider context differences while designing several different versions of the same user interface. For end users, web pages that are not adapted become often inaccessible in non-conventional contexts of use, with mobile devices, as smart phones and tablet PCs. In order to leverage such efforts, we propose in this paper a meta-model that by means of a unified view supports all phases of the implementation of context-aware adaptation for user interfaces. With such a formal abstraction of an interactive system, stakeholders can generate different instantiations with more concrete UI’s that can properly handle and adapt accordingly to the different constraints and characteristics of different contexts of use. We present CAMM, a meta-model for context-aware adaptation covering different application domains and also a complete adaptation lifecycle. Moreover we also present various instantiations of such a model for different scenarios of a car rental example.

The paper describes an engineering approach for building user interfaces for synchronous peer co-engagement in virtual work by operating with, on, through and within different digital representations. The proposed approach introduces several extensions to the UsiXML family of models as well as design and runtime support for multi-platform, synchronous and collaborative interactions. We demonstrate the key concepts by elaborating a scenario of collaborative co-play of a soccer game. The specific example features synchronous co-play by remote users in different roles (players or observers), a range of devices (PCs or Android) and interaction facilities (visual and non-visual).

La structure par termes des taux d'intérêt est depuis longtemps considérée comme une source potentielle d'informations sur les évolutions macroéconomiques à venir. La meilleure illustration de cette vision répandue concernant la caractéristique prédictive de la courbe des rendements réside dans la théorie des attentes. Selon cette théorie, l'inclinaison de la courbe des rendements reflète les attentes des intervenants de marché quant à la trajectoire future moyenne des taux d'intérêt à court terme. Dans une telle optique, il semble logique de recourir à la courbe des rendements pour émettre des prévisions quant aux agrégats macroéconomiques tels que l'activité économique réelle et l'inflation. Dans le modèle de la théorie des attentes, les rendements obligataires sont exclusivement déterminés par la trajectoire anticipée des taux d'intérêt à court terme et intègrent une composante de prime de terme nulle ou constante. Or, si les rendements obligataires sont en partie constitués de primes de terme variables dans le temps, non seulement la théorie des attentes ne tient pas, mais le contenu informatif de la courbe des rendements quant aux agrégats macroéconomiques pourrait s'en ressentir. Aussi, déterminer la contribution des composantes des rendements obligataires que sont les anticipations et la prime de terme pourrait permettre, d'une part, d'interpréter avec plus de précision la dynamique de la structure par termes des taux d'intérêt et, d'autre part, d'établir de meilleures variables informatives utiles aux projections macroéconomiques. La présente étude analyse l'échec de la théorie des attentes et ses conséquences pour les projections macroéconomiques. Elle adopte le modèle macrofinancier étendu (Extended Macro-Finance model) mis au point par Dewachter et Iania (2011), qui complète les modèles macrofinanciers ordinaires de la structure par termes des taux d'intérêt en y ajoutant trois facteurs financiers et deux tendances stochastiques. Les deux premiers facteurs financiers traduisent les tensions financières à l'œuvre sur le marché financier, tandis que le troisième isole les variations temporelles des primes de risque des obligations. Les deux tendances stochastiques permettent de parvenir à des processus hautement persistants qui appréhendent les variations temporelles des anticipations d'inflation à long terme et du taux réel d'équilibre, deux composantes essentielles des anticipations relatives aux taux d'intérêt à long terme. Elle examine, sous l’angle de ce modèle macrofinancier, deux éléments pertinents liés à l'échec de la théorie des attentes, à savoir la dynamique des primes de risque des obligations et le contenu informatif de l'écart de terme ainsi que des anticipations et de la prime de terme en vue d'établir des projections en matière d'activité économique et d'inflation. Les contributions de la présente analyse à la littérature macrofinancière actuelle sont multiples. Premièrement, elle montre que le modèle macrofinancier étendu est capable d'extraire des estimations raisonnables de la dynamique de la prime de terme. La dynamique de la prime de terme utilisée aux fins de l'analyse est semblable à celle de Kim et Wright (2005), qui est considérée par Rudebusch, Sack et Swanson (2007) comme la mesure la plus représentative parmi les cinq mesures que ces auteurs ont examinées. Pour ce faire, il est recouru à un facteur unique à titre de principal moteur des primes de risque des obligations qui reproduit l'essentiel de la corrélation au niveau du rendement excédentaire réalisé. Ce facteur est comparable au facteur de prévision du rendement proposé par Cochrane et Piazzesi (2005), le facteur CP, qui est cependant extrait en recourant à des régressions prédictives ad hoc. En comparaison du rendement excédentaire réalisé, les primes de risque tirées du modèle utilisé ici ne sont pas entachées d’un biais et génèrent une adéquation à l’échantillon et des prévisions hors échantillon conformes à celles obtenues par la méthode de Cochrane et Piazzesi (2005). Deuxièmement, l'analyse montre (i) que les anticipations relatives aux obligations à court terme sont principalement portées par les chocs de politique monétaire, tandis que celles liées aux obligations à long terme sont influencées par tous les chocs macroéconomiques, en particulier les chocs d'inflation persistants et (ii) que les évolutions de la prime de terme sont essentiellement associées à des chocs financiers, avec une incidence limitée des chocs de liquidité et de taux directeurs. Ces résultats montrent que la pertinence de l'introduction de critères stochastiques et de la dynamique des primes de risque dans un modèle macrofinancier ne se limite pas à renforcer la fiabilité de la courbe des rendements, mais est également essentielle pour identifier les anticipations des rendements obligataires et la prime de terme. Troisièmement, il ressort de l'analyse que, s'il est essentiel de décomposer l'écart de terme entre anticipations, d'une part, et prime de terme, d'autre part, pour prévoir les variations de l'inflation, cette décomposition est moins pertinente lorsqu'il s'agit d'émettre des projections relatives à l'activité réelle. Les résultats de l'analyse laissent à penser que recourir à l'écart de terme pour inférer les variations futures de l'inflation (en se fondant par exemple sur l'hypothèse de Fisher) pourrait ne pas générer le résultat escompté, parce que le contenu informatif de l'écart de terme est influencé par la présence de la composante de la prime de risque. Ce constat est demeuré constant durant la décennie écoulée et résiste à l'inclusion de variables de contrôle. En ce qui concerne les mesures de l'activité réelle, comme la croissance du PIB en volume ou l'écart de production, la décomposition de l'écart de terme revêt une moindre importance. S'agissant de la croissance du PIB, l'analyse montre que l'augmentation du R² ajusté n'est généralement pas statistiquement significative. Quant à l'écart de production, les résultats sont partagés. Lorsque l'écart de terme est utilisé comme unique variable prédictive, la décomposition entre les anticipations et la prime de terme accroît nettement le contenu prédictif de l'écart de production. En revanche, cette amélioration disparaît dès lors que l'on introduit des variables de contrôle pour la valeur actuelle de l'écart de production et du taux d'intérêt à court terme. L'analyse montre par ailleurs, exemples à l'appui, que la décomposition de l'écart de terme a perdu de sa capacité projective pour les deux mesures de l'activité réelle au cours de la dernière décennie.

Culture plays a role in the way humans interact with the machine. It implies changes on the UI to fit cultural needs, practices and preferences. Knowledge on these implications are sparsed and insufficient until the moment. Employing culture knowledge as rules in the design and development of software user interfaces looks far to achieve. Even though, user interface designers and developers still need to consider differences in user interfaces. Our approach to support user interface developers and designers is to propose a user interface architecture that enhances their ability to apply changes imposed by culture. Our contribution is to analyse culture studies to identify concerns and requirements for such architecture, propose an architecture that satisfies some of these requirements and discuss an idea towards an enhanced one.

This dissertation consists in three essays that investigate liquidity provision dynamics up to high frequency sampling scheme. The latest evolution of financial markets towards both more trading fragmentation and the emergence of high frequency traders make liquidity provision a topical issue. The first essay provides a novel methodology to forecast liquidity as a trade size specific concept using time series modeling. The second essay focuses on the prominence of market disruptions in the stock market. It investigates what are the most informative microstructure variables with respect to market disruptions’ occurrence. Finally, the third essay documents the trading behavior of high frequency traders (HFT) around market disruptions. Indeed, HFT are often referred to as threatening financial markets’ stability. Altogether, those essays hold implications for both market participants and regulators. Suite à la crise financière de 2008 et au flash crash de 2010, l’efficience et la stabilité des marchés financiers sont, encore plus qu’auparavant, des sujets d’actualité. En atteste, les dernières avancées au niveau de la régulation des marchés financiers tant aux Etats-Unis qu’en Europe qui ont permis une amélioration de la qualité des marchés financiers en général. Cependant, ces avancées ont également eu des conséquences inattendues telles que l’apparition de ‘dark pools’ qui sont des plateformes de négociation totalement opaques tant pour les autres investisseurs que pour les régulateurs ou l’avènement du trading à haute fréquence dont la stratégie repose essentiellement sur une exécution d’ordres à grande vitesse, de l’ordre de quelques microsecondes. Dans ce contexte, cette thèse étudie la dynamique de provision de liquidité dans les marchés financiers. Les implications de ce travail vont de l’amélioration de la gestion des prix d’exécution pour les participants au marché à une plus grande compréhension de l’impact des traders à haute fréquence dans les marchés financiers. (ECGE - Sciences économiques et de gestion) -- UCL, 2014

An effective User Interface (UI) is a key success factor for interactive systems. Hence, particular attention should be paid to the UI design during the Requirement Engineering process (RE). Several RE tools have been proposed in order to support the UI design. However, these tools have limitations in terms of requirements completeness, requirements quality analysis and UI generation from requirements. In this paper, we present a new RE toolkit called QualIHM, that deals with the limitations of the existing RE. The toolkit supports the description of requirements in different formats. In addition, QualiHM facilitates the UI design by transforming requirement formats from one to another, generating the UI code and providing feedback about the aesthetic of the UI.

The rapid growth of firms worldwide causes that relationships in supply chains become more complex, the competition between firms become stronger and customer ask for more demanding products and services. All these changes trigger that a firm looks for opportunities to get more from their scarce resources or to use resources that are beyond its direct control. Thus, a firm can achieve competitive advantages by setting partnerships with other supply chains in order to increase its production capacity, by adapting its operations and pricing strategies to the requirements of the market, and by differentiating between customers according to necessities and willingness to pay for its offered products. We start by studying how firms with similar supply chain roles can collaborate in their operations. Through this collaboration, the firms can mutually benefit from the synergies of pooling operations. A successful collaboration should be efficient in reducing the global cost of the firms. Nevertheless, the willingness of each firm to collaborate may also depend on the fairness of the global cost allocation. In order to guide joint operations, we propose a novel approach that gives priority to the firm that tends to benefit less from the collaboration. In particular, our approach balances the global cost reduction and the inequalities of allocating such cost. Moreover, when analyzing the effect of the uncertainty on the collaboration, our approach shows a high efficiency in reducing risk in comparison to other approaches. We continue by studying how a firm can coordinate its pricing strategy and production and inventory decisions in order to compete with other firms in terms of the prices offered to the customers. We propose a framework for simultaneously planning prices and operations of a firm. We model the operations of the firms as a Lot sizing problem, so computing equilibrium between the prices becomes a time demanding task. We reduce significantly the computational time by providing bounds for the profits that firms can achieve by selecting a pricing strategy. Also, we show the convenience for the firms of using dynamic pricing strategy instead of static pricing strategy, and we show the negative effects that may arise when increasing production capacities. We also study how a firm can gain from differentiating the demand of their customers based on profits and manufacturing requirements. Our study is motivated by the case of a firm that faces two types of demand: on the one hand there are the socalled regular orders that have a relatively long lead time; on the other hand there are urgent orders, whose delay is much shorter but their margins are higher. We study the order acceptance problem for a firm that serves two classes of demand over an infinite horizon. The firm has to decide whether to accept a regular order (or equivalently how much capacity to set aside for urgent orders) in order to maximize its profit. We formulate this problem as a multi-dimensional Markovian Decision Process. We propose a family of approximate formulations to reduce the dimension of the state space via aggregation. We show how our approach can be used to compute bounds on the profit associated with the optimal order acceptance policy. Finally, we show that the value of revenue management is commensurate with the operational flexibility of the firm. (ECGE - Sciences économiques et de gestion) -- UCL, 2014

Expectations of customers regarding variety, customization, fast and reliable due dates of products have been increasing over time. Meeting this demand is a constant challenge for companies given their limited resources. Finding the balance between customers' requirements from one side and companies operations from the other has shown to be an arduous task; variabilities in either demands or operations could have significant negative consequences on companies' performances. These variabilities could cause the planning problems, creating production delays, long and unreliable due date lead times and straining relationships with customers. As a consequence, more and more companies are interested in finding mechanisms allowing them to produce more efficiently in an environment that is increasingly subject to variability. In this thesis we provide a new perspective on how to implement capacity allocation strategies in order to achieve the desired profits and high due-date adherence. Here we show how to model: (i) capacity sharing with lead time decisions, and (ii) capacity allocation with admission control decisions. In the first part of the thesis, we study a capacity sharing strategy allowing manufacturing operations for heterogeneous products to be pooled. The literature on the design of service systems revealed that, in a stochastic environment, pooling naturally leads to economies of scale, but heterogeneity can create variability. We investigate this trade-off in the case of a manufacturer assigning due dates to customers in order to guarantee a high service level. We develop a simulation and analytical study based on queueing theory in order to gain insights into the impact of pooling on the due date performance. With this work we show that heterogeneity does not necessarily lead to deterioration of performance, as previously reported in studies of service environments. We show that in case of increased product variety and utilization rate, the heterogeneity can be exploited in our advantage. Next, we demonstrate how companies can attain high due date performance by making collaborative decisions to pool their resources within supply chains. In particular, we find that capacity sharing leads to better overall performance than producing separately even for very high heterogeneity. However, the decision regarding the due-date setting and scheduling policy to implement can have a significant impact on the individual performance. Finally, our study reveals that the benefits of pooling in terms of the expected sojourn time obtained by a simple analytical treatment serve as a good prediction of the benefits of pooling on the due date performance in a wide range of situations. In the second part of the thesis, we propose a new capacity allocation scheme with admission control decisions for a company that processes orders from multiple demand streams. Given that the capacity may be insufficient to cater for all demands while meeting their promised due dates, the company has to decide whether to accept or reject incoming orders in order to maximize its profit. We formulate this problem as a multi-dimensional Markov Decision Process to gain insights into the optimal policy. The description and calculation of the optimal policy can be highly complex. Thus we provide a family of approximate formulations to reduce the dimension of the state space via aggregation. We compute bounds on the profit associated with the optimal order acceptance policy to measure the efficiency of the approximate formulations for large instances. We then demonstrate that the structure of the optimal policy is threshold based for almost every state of the system in case of stochastic order sizes. We propose threshold based policies in order to further reduce the complexity of the formulations. Our results show the superiority of the proposed formulations over known methods widely used in the literature. In particular, our policies provide near-optimal solutions quickly and stand out for their robust performance with respect to changes in operational conditions and with respect to differences between the actual and estimated demands. (ECGE - Sciences économiques et de gestion) -- UCL, 2014

In this thesis, we mainly consider two closely related classical and general problems in data mining and machine learning: (1) developing new similarity measures between graphs and between nodes of a graph, and (2) developing new density measures on nodes of a graph. In the first part of this thesis, we introduce three new graph kernels (which can be seen as similarity measures between graphs) and assess them on a graph classification task: using molecules from various origins as graphs, we try to classify them according to one of their property (mutagenicity,...). We then study the problem of quantifying the similarity between nodes of graphs. We define three new measures by assigning the forests present in the graph a probability of being sampled at random, favoring small (low-cost) forests against bigger ones. These measures are then assessed on a semi-supervised classification task, trying to infer missing node labels from the ones already present in the test datasets. From these similarity measures, we developed the Sum-over-Forests (SoF) density index presuming that, when picking forests (which are assigned a probability of sampling), if a node is present in many (preferably short) forests, it should lie in a dense region of the graph. This density index is then assessed in various ways, assessing its quality as a density estimator on graphs. At last, we developed two clustering algorithms based on the SoF density index, which are able to work directly on graphs without necessarily requiring a priori the number of clusters. Notre recherche doctorale s’intéresse principalement à deux problèmes étroitement liés, dans les domaines de l’analyse de données et de l’apprentissage automatique: (1) le développement de nouvelles mesures de similarité entre graphes et entre nœuds d’un graphe, et (2) le développement de nouvelles mesures de densité sur les nœuds d’un graphe. Dans la première partie de ce document, trois nouveaux noyaux sur graphes, pouvant être considérés comme des mesures de similarité entre graphes, sont introduits. Ces noyaux sont évalués sur une tâche de classification dont l’objectif est de classer des molécules d’origines diverses, modélisées sous forme de graphes, suivant une de leurs propriétés (mutagénicité,…). Dans notre recherche sur la quantification de la similarité entre nœuds d’un graphe, trois nouvelles mesures ont été définies en assignant aux forêts présentes dans le graphe une probabilité d’être choisies au hasard, favorisant les petites forêts (ayant un coût faible) au détriment des plus étendues. Ces mesures sont ensuite évaluées sur une tâche de classification semi-supervisée dont l’objectif est de prédire les étiquettes manquant sur certains nœuds à partir de celles attachées aux autres nœuds. De ces mesures de similarité, un indice de densité d’un nœud d’un graphe, appelé « Sum-over-Forests » (SoF), a été développé en supposant qu’un nœud présent sur beaucoup de forêts (de préférence petites – et donc avec une plus forte probabilité d’être choisies au hasard) devrait être situé dans une région dense du graphe. Cet indice de densité est ensuite testé de différentes manières, évaluant sa qualité en tant qu’estimateur de densité sur graphes. Enfin, deux méthodes de clustering de nœuds, basées sur l’indice de densité SoF, pouvant être appliquées directement sur des graphes et ne nécessitant pas a priori le nombre de clusters à obtenir, ont été mises au point. (ECGE - Sciences économiques et de gestion) -- UCL, 2014

Wireframes are useful for discussing and refining the user interface of a new application. After the client has validated the GUI, frequently developers have to spend time on recreating the GUI in a development environment for a specific language, and then the created wireframes are discarded. We propose a model-based approach to infer the high level layout of the GUI based on wireframes in order to be able to generate a proper final GUI for different technologies.

This doctoral thesis is composed of four essays that relate price movements to market liquidity at the intraday level. This issue is of utmost importance because liquidity is multidimensional and difficult to accurately estimate. Our approach is based on the quest for easy-to-observe proxies for liquidity. In this respect, intraday prices are useful since they are widely available. The first essay consists in an event study that investigates whether particular High-Low-Open-Close price dynamics have an informational content towards liquidity. The second paper refines the previous study by investigating which types of price movements best characterize changes in the state of liquidity. The third essay discusses the use of zero returns as a liquidity proxy. Finally, the last essay investigates how transactions costs may be improved using the findings of the three previous essays. All in all, we conclude that intraday price movements are related to liquidity and that market participants may benefit from particular price patterns to place orders at lower cost. Cette thèse de doctorat comporte quatre essais qui associent les mouvements de prix à la liquidité de marché sur un horizon intrajournalier. Cette question est d’une grande importance puisque le caractère multidimensionnel de la liquidité en rend l’estimation difficile. Notre approche se base sur la recherche d’indicateurs de liquidité faciles à observer. A cette fin, les prix intrajournaliers peuvent être utiles, étant donnée leur accessibilité. Le premier essai consiste en une étude d’événements qui analyse le contenu informationnel de dynamiques de prix High-Low-Open-Close particulières envers la liquidité. Le second essai complète la précédente étude en étudiant quels types de mouvements caractérisent au mieux les changements de liquidité. Le troisième essai discute l’utilisation des rendements égaux à zéro en tant qu’indicateurs de liquidité. Enfin, le quatrième essai examine comme les coûts de transaction peuvent être améliorés à la lumière des résultats obtenus dans les essais précédents. En conclusion, cette thèse de doctorat démontre que le mouvements de prix sur base intrajournalière sont associés à la liquidité de marché et que les participants au marché peuvent en bénéficier pour placer des ordres à bas coût. (ECGE - Sciences économiques et de gestion) -- UCL, 2013

This paper addresses the problem of modernizing graphical user interfaces of interactive applications by re-engineering their resource files in four phases: resource decompilation, which extracts resource files from the executable code of an interactive application; modeling the source user interface, which transforms extracted resources into a resource model; resource to user interface transformation, which transforms the resource model into a Concrete User Interface model, and forward engineering, which offers two alternatives: after editing the user interface model, a new interface could be generated or recompiled into a resource to be incorporated back. The paper motivates and details this re-engineering approach by focusing on methods and algorithms implemented in UsiResourcer, a software tool that reverse engineers MS Windows resource files into a Concrete User Interface Model for further process. A discussion on the generalization of the approach is also provided.

Designing interactive systems for multiple contexts of use becomes a burden when several interaction scenarios, their characteristics and constraints, must be considered. Stakeholders face then two main challenges: they are not aware of what is significantly relevant to consider from contextual information,or how to appropriately adapt the user interfaces based on this information considered. Moreover,stakeholders cannot count on existing UI editors once they usually do not provide support for context-aware adaptation. Thus, adaptation is often ignored, resulting in user interfaces that are only suitable for static and conventional contexts of use. To support the design of user interfaces that are properly adapted to their target context, this paper proposes a novel methodology to enhance sketching activities by suggesting to the end user adaptation guidelines. This work aims at raising awareness about context-aware adaptation since the early stages of the UI design.

The recent popularization of touch screen devices have brought to users the opportunity to use different devices to interact and to share content, while current advances in the mobile context brought new capabilities for systems to run on many devices while maintaining the system’s consistency. Those two factors combined pose new opportunities for re- searchers to explore how users can collaborate using an heterogeneous set of devices, that can include large tabletops, smartphones or e-readers. This paper starts the discussion on four challenges related to this context.

Distributed User Interfaces (DUIs) have recently become a new field of research and development in Human- Computer Interaction (HCI). The DUIs have brought about drastic changes affecting the way interactive systems are conceived. DUIs have gone beyond the fact that user interfaces are controlled by a single end user on the same computing platform in the same environment. This new interaction mechanism affects the way these novel systems are designed and developed. New features need to be taken into account from the very beginning of the development process and new models, methods, and tools need to be considered for the correct development of interactive systems based on Distributed User Interfaces. Therefore, the goal of this workshop is to promote the discussion about the emerging topic of DUIs, answering a set of key questions regarding their development: How current UI models can be used or extended to cover the new features of DUIs? What new features should be considered and how should they be included within the development process? What new methods and methodologies do we need to develop DUIs in a correct way following the quality standards for interactive systems?

The scientific community has already investigated in depth the benefits of combining model-based approaches for implementing context-aware adaptation. As benefits, it can be highlighted: lower development costs, faster time to market, higher usability levels, optimal usage of the resources available and a better user interaction. Although these benefits are claimed, for practitioners it may be not always evident that they actually compensate for the costs of incorporating such practices into daily work practices. Based on the hypothesis that such practices are not widely adopted, we defined and applied a survey of practitioners to identify if and how they actually perceive and adopt such approaches. This paper describes the survey, its application and discusses the results obtained.

The paper focuses on the building of nurses’ timetabling and surgical teams knowing the weekly schedule. The objective of the sequential approach adopted is to be able to do teams with high affinities while using the nurses efficiently. The problem is modeled as a mixed integer program and offers flexibility to consider any work pattern. The model is tested on real hospital data.

Income inequality undermines societies: The more inequality, the more health problems, social tensions, and the lower social mobility, trust, life expectancy. Given people’s tendency to legitimate existing social arrangements, the stereotype content model (SCM) argues that ambivalence―perceiving many groups as either warm or competent, but not both―may help maintain socio-economic disparities. The association between stereo- type ambivalence and income inequality in 37 cross-national samples from Europe, the Americas, Oceania, Asia, and Africa investigates how groups’ overall warmth-compe- tence, status-competence, and competition-warmth correlations vary across societies, and whether these variations associate with income inequality (Gini index). More unequal societies report more ambivalent stereotypes, whereas more equal ones dislike competitive groups and do not necessarily respect them as competent. Unequal societies may need ambivalence for system stability: Income inequality compensates groups with partially positive social images. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP)

The EU-funded Serenoa Project (www.serenoa-fp7.eu) is creating a novel open platform for developing context- aware application user interfaces. Such user interfaces are aware of the changes in the context and can react to them in a continuous way. This includes adaptation to the user's devices, tasks, preferences and abilities, thereby improving the user's satisfaction and performance compared to traditional approaches to user interface design. An additional benefit is a reduction in the cost and development time for creation and maintenance of user interfaces.

This note provides a discussion of the presentation made by Claus Kreiner, which was based on his joint article with Kleven, Knudsen, Pedersen and Saez (Kleven et al., 2011). The comments especially focus on some aspects of the article, supposed to be relevant for a policy debate. Therefore the aim of this discussion is not to comment on its technicality but rather to focus on the theoretical framework and on the use of the paper for policy debates.

Prototypes are essential tools for design activities for they allow designers to realize and evaluate ideas in early stages of the development. Sketching is a primary tool for constructing prototypes of interactive systems and has been used in developing low-fidelity prototypes for a long time. The computational support for sketching has been receiving a recurrence of interest in the last 45 years and again nowadays within the mobile web context, where there are diverse devices to be considered. The research reported on this paper aims at addressing issues on multi-platform collaborative sketching using a prototyping tool for user interfaces. The tool was built to aid the investigation on how designers sketch using many different devices and collaborate using their sketches during design sessions.

This paper analyses aspects of financing within the Bologna Process, with a focus on the financing of student mobility. It argues that the current system for financing cross-border student mobility, based on the host country, appears to be neither sustainable nor efficient. Against this background, and motivated by a recent decision of the European Court of Justice, the paper explores two alternative solutions. The first one envisages substituting financing by the host country with financing by the country of origin, possibly through vouchers that students may use at home or abroad (provided the quality of education in the host institution has been recognised). The second one combines this substitution with a reimbursement of education costs through interjurisdictional transfers or the change of vouchers into contingent loans.

This study investigates characteristics of individual crowdfunding practices and drivers of fundraising success, where entrepreneurs can tailor their crowdfunding initiatives better than on standardized platforms. Our data indicate that most of the funds provided are entitled to receive either financial compensations (equity, profit-share arrangement) or non-financial benefits (final product, token of appreciation), while donations are less common. Moreover, crowdfunding initiatives that are structured as non-profit organizations tend to be significantly more successful than other organizational forms in achieving their fundraising targets, even after controlling for various project characteristics. This finding is in line with theoretical arguments developed by the contract failure literature that postulates that non-profit organizations may find it easier to attract money for initiatives that are of interest for the general community due to their reduced focus on profits.

This paper investigates the consequences of a series of alternative international tax designs on the strategy of a multinational enterprise regarding the cross border distribution of its investment and the choice of its financing behavior. We start with a world where no international tax rules are at work. Then we successively introduce (i) the rules provided by the OECD Model Tax Convention, (ii) the EU Parent-Subsidiary Directive of July 23, 1990; and (iii) a combination of Allowance for Corporate Equity (ACE) and Comprehensive Business Income Tax (CBIT). Finally, we leave systems based on Separate Accounting (SA) aside and turn to Consolidation and Formulary Apportionment (C&FA) adopted either by all the jurisdictions at work in the model, or by a sole subset of them within the framework of an Enhanced Cooperation Agreement (ECA). JEL: F23, H25, K34

The purpose of this work is to understand some existing user interface patterns and to adapt them to the constraints of mobile devices running on the Android system. We focus mainly on the Master/Detail pattern and on the surrounding patterns. The contributions are multiple: our background study consists of a brief recall of the principles of some existing user interface patterns. Based on it, we provide an adapted version of each pattern targeted to mobile phones through a framework called MandroiD. We will also present a basic case study application that takes advantage of the framework. This application is developed with Android guidelines in mind. Indeed, one of our goals is to provide the reader with some knowledge about Android applications development. Limitations of general mobile devices (e.g., the small screen) require of "reducing" homogeneous elements. MandroiD overcome theses constraints. A statistical analysis is conducted on the developed mini-application. Evaluation of it shows a general satisfaction concerning the ergonomy of the application by various users.

An effective adaptation of user interfaces approximates technological benefits to the actual needs, wishes and requirements of end users. Today the significant heterogeneity of contexts of use, given mainly by the diversity of devices and the easier access to technology, enables an interaction from many distinct environments and covers different application domains and users’ profiles. However the majority of the applications currently available still rely in a conventional context of use, i.e. an able-bodied user, with a Desktop PC in stable environment. Thus several usability issues are often found, requiring a deeper investigation of how adaptation can be efficiently defined and analyzed regardless of application domains. This paper proposes a theoretical framework that considers dimensions of context and adaptation to support stakeholders in the specification and analysis of context- aware adaptation.

This article examines how the introduction of an ETF replicating a stock index impacts on the liquidity of the underlying stocks. We find that index stock spreads decline, relative to those of non index stocks, after the introduction of the ETF. Changes in adverse selection do not appear to be a major factor explaining this liquidity improvement. We also fail to relate it to recognition effects. By contrast, we think that it can mainly be explained by a decrease in order processing and order imbalance costs. This is consistent with the arbitrage theory of Fremault (1991) according to which increased cross-market trading provides additional risk sharing capacity.

The concept of meta-organization has attracted great interest from research perspectives since 2005. It is seen as a way to reflect the current organizational reality characterized by associations of independent organizations working together to achieve a common goal. Meta-organization allows understanding globalization and internationalization of our world. However, little has been done on meta-organization. Its understanding remains still poorly developed. This paper focuses on an international sport organization, namely World Anti-doping Agency, which aims at harmonizing the fight against doping in sport. We argue that sport field highlights relevant attributes of meta-organization which help to establish a better understanding of sport organizations’ management and meta-organization’s concept. Their attributes (e.g. openness of boundaries, internal stratification, and consensus decision-making) help to establish a better understanding of international sport associations. This paper contributes to a better knowledge of meta-organization and serves as a starting point for future research in the management of sport organizations.

Electronic sketching has received a recurrence of interest over the years and again nowadays within the mobile web context, where there are diverse devices, operating systems and browsers to be considered. Multi-platform (e.g. web-based) sketching systems can be constructed to allow users to sketch on their device of preference. However, web applications do not always perform equally on all devices, and this is a critical issue, especially for applications that require instant visual feedback such as sketch-based systems. This paper describes a user study conducted to identify the most appropriate response rates (expressed in frames per second) for end users while sketching. The results are expected to guide stakeholders in defining response parameters for sketching applications on the web by showing intervals that are accepted, tolerated, and rejected by end users.

Este trabajo presenta una colección de patrones de diseño de interfaces de usuario para sistemas de información para el flujo de trabajo; la colección incluye cuarenta y tres patrones clasificados en siete categorías identificados a partir de la lógica del ciclo de vida de la tarea sobre la base de la oferta y la asignación de tareas a los responsables de realizarlas (i. e. recursos humanos) durante el flujo de trabajo. Cada patrón de la interfaz de usuario de flujo de trabajo (WUIP, por sus siglas en inglés) se caracteriza por las propiedades expresadas en el lenguaje PLML para expresar patrones y complementado por otros atributos y modelos que se adjuntan a dicho modelo: la interfaz de usuario abstracta y el modelo de tareas correspondiente. Estos modelos se especifican en un lenguaje de descripción de interfaces de usuario. Todos los WUIPs se almacenan en una biblioteca y se pueden recuperar a través de un editor de flujo de trabajo que vincula a cada patrón de asignación de trabajo a su WUIP correspondiente.A collection of user interface design patterns for workflow information systems is presented that contains forty three resource patterns classified in seven categories. These categories and their corresponding patterns have been logically identified from the task life cycle based on offering and allocation operations. Each Workflow User Interface Pattern (WUIP) is characterized by properties expressed in the PLML markup language for expressing patterns and augmented by additional attributes and models attached to the pattern: the abstract user interface and the corresponding task model. These models are specified in a User Interface Description Language. All WUIPs are stored in a library and can be retrieved within a workflow editor that links each workflow pattern to its corresponding WUIP, thus giving rise to a user interface for each workflow pattern.

Adapting user interfaces according to the context of use aims at improving the usability levels of an application and enhancing the user experience, mainly by optimizing the users’ interaction and reducing their errors. However, given the significant amount of information involved, adapting UIs often demands complex inferences. Because the context information is extensive, it is hard to prioritize it to decide the best adaptation techniques. Moreover, dealing with recurrent trade-offs, e.g. adaptability vs. performance, is not simple. To aid the adaptation decisions, machine learning algorithms can be applied to support reasoning, inferences and also to deal with complex or fuzzy information. Although ML can provide several benefits for CAA, there is no agreed framework that aids developers in applying it. Thus, aiming to fill such a gap, this paper defines potential scenarios of CAA where ML can be successfully applied, presenting their common requirements and main trade-offs.

Three sources of strategic tax interactions among local jurisdictions are usually considered in the literature: public expenditure spill-over, tax competition and yardstick competition. However, another source has now been suggested: the intellectual trend. According to that hypothesis, politicians of the same party tend to behave similarly: incumbents of the same party mimic each other's policies. Moreover partisan politics may also act through a monopoly power effect linked to several terms of power for the same party, consecutively: a political party is more likely to have implemented tax rates corresponding to its ideology if it has ruled the municipality several legislatures in a row. The paper proposes an empirical analysis of tax interactions among Walloon municipalities (the Southern part of Belgium) in view of discriminating among the sources of interaction. Yardstick hypothesis, intellectual trend hypothesis and potential partisan monopoly power effect are tested. Spatial econometrics tools are used along a panel of local tax rates data from 1983 to 2008 and political data. Results confirm the existence of yardstick competition among Walloon municipalities but not that of behaviors in line with the intellectual trend hypothesis. Moreover evidence is found of a partisan monopoly power effect: several successive legislatures with a sole left-wing party in power increase the tax rates. Finally the presence of an electoral cycle is also clearly documented.

Given a graph with nonnegative edge weights and node pairs Q, we study the problem of constructing a minimum weight set of edges so that the induced subgraph contains at least K edge-disjoint paths containing at most L edges between each pair in Q. Using the layered representation introduced by Gouveia, we present a formulation for the problem valid for any K; L >= 1. We use a Benders decomposition method to efficiently handle the big number of variables and constraints. We show that our Benders cuts contain the constraints used by Huygens et al. to formulate the problem for L = 2; 3; 4, as well as new inequalities when L >= 5. While some recent works on Benders decomposition study the impact of the normalization constraint in the dual subproblem, we focus here on when to generate the Benders cuts. We present a thorough computational study of various branchand- cut algorithms on a large set of instances including the real based instances from SNDlib. Our best branch-and-cut algorithm combined with an efficient heuristic is able to solve the instances signicantly faster than CPLEX 12 on the extended formulation.

PurposeThis paper aims to present a case study of the application of a methodology that represents an innovative strategy that integrates researches on interaction design and business process management with practical implications. This methodology is devoted to aligning the needs of enterprise system users with business processes (BPs).Design/methodology/approachThis approach establishes an unbroken network of links between BPs, task models and abstract representations of user interfaces. Once the models are linked, it is possible to identify the impact that any change on these models may produce in other models. The main challenge is to organize the linked models according to the organizational context and manage those links with consistency in order to support improving process efficiency and user productivity. This approach has been applied in a large telecommunications organization during four months with its application in two different projects and validated with a cost‐benefit analysis.FindingsApplying this approach in large organizations has demonstrated that: every involved stakeholder is capable of understanding the whole approach in one working day; creating the models and linking them with the corresponding business process models takes around three men/day per core business process; and applying this approach brings up to 60 per cent of return on investment related to process improvement and user experience.Originality/valueThe main differentials of this methodology include using simple models; considering light actions; preserving the independence of technology; and adopting a human‐oriented approach assuring that every managed information impacts people and not only systems, thus enabling fast adaptation to the business dynamism.