Query processing of spatial objects: Complexity versus Redundancy

The management of complex spatial objects in applications, such as geography and cartography, imposes stringent new requirements on spatial database systems, in particular on efficient query processing. As shown before, the performance of spatial query processing can be improved by decomposing complex spatial objects into simple components. Up to now, only decomposition techniques generating a linear number of very simple components, e.g. triangles or trapezoids, have been considered. In this paper, we will investigate the natural trade-off between the complexity of the components and the redundancy, i.e. the number of components, with respect to its effect on efficient query processing. In particular, we present two new decomposition methods generating a better balance between the complexity and the number of components than previously known techniques. We compare these new decomposition methods to the traditional undecomposed representation as well as to the well-known decomposition into convex polygons with respect to their performance in spatial query processing. This comparison points out that for a wide range of query selectivity the new decomposition techniques clearly outperform both the undecomposed representation and the convex decomposition method. More important than the absolute gain in performance by a factor of up to an order of magnitude is the robust performance of our new decomposition techniques over the whole range of query selectivity

ICT–supported reforms of service delivery in Flemish cities: testing the concept of 'information ecology'

This paper explores organizational reforms in Flemish cities related to making the cities’ individual service delivery more efficient, customer orientated, customer friendly and integrated. The paper is the first one of a recently started research project and PhD research about the complexity of managing ICT-supported change of ‘individual’ service delivery. The overall objective of this paper is to set the stage for the research project’s research design in terms of its theoretical framework. Therefore, we report about our first explorative, inductive and descriptive findings related to this type of change within one city. We firstly inductively report about the objectives and the objects of change. Secondly, we develop a provisional theoretical framework. We therefore take the notion of an information ecology as a conceptual starting point and use a combination of elements of neo-institutional theory, system theory and a political perspective on organizational development. In order to explore the potentialities of this approach, we test the framework’s value for understanding the changes within the city. The framework enabled us to describe and analyze this type of reforms without neglecting the complexity of these changes. It tries to link some important public administration theories to the study of the e-government phenomenon that is still an important challenge. The most important lesson is that further refinement of the conceptual framework is needed. Although the analysis shows that the framework offers a conceptual basis to analyze front and back office reforms within public organizations, it still lacks a full and straightforward operationalization of its components, constructs, relations, etc

ADO: An Active Distributed Object-Oriented Database Model

Object-oriented databases are emerging as a newgeneration database technology for complex applications. In this paper, we present an active distributed object-oriented (ADO) database model, which can capture not only passive behaviors but also active behaviors of complex objects. Besides, the distribution nature of objects can be reflected from within the model as well. Based on the model, we have developed a prototype active distributed object-oriented database management system, and applied it to a housing property management application

The Vadalog System: Datalog-based Reasoning for Knowledge Graphs

Over the past years, there has been a resurgence of Datalog-based systems in the database community as well as in industry. In this context, it has been recognized that to handle the complex knowl\-edge-based scenarios encountered today, such as reasoning over large knowledge graphs, Datalog has to be extended with features such as existential quantification. Yet, Datalog-based reasoning in the presence of existential quantification is in general undecidable. Many efforts have been made to define decidable fragments. Warded Datalog+/- is a very promising one, as it captures PTIME complexity while allowing ontological reasoning. Yet so far, no implementation of Warded Datalog+/- was available. In this paper we present the Vadalog system, a Datalog-based system for performing complex logic reasoning tasks, such as those required in advanced knowledge graphs. The Vadalog system is Oxford's contribution to the VADA research programme, a joint effort of the universities of Oxford, Manchester and Edinburgh and around 20 industrial partners. As the main contribution of this paper, we illustrate the first implementation of Warded Datalog+/-, a high-performance Datalog+/- system utilizing an aggressive termination control strategy. We also provide a comprehensive experimental evaluation.Comment: Extended version of VLDB paper <https://doi.org/10.14778/3213880.3213888

Alignment of Partnering with Construction IT

Supply Chain Management (SCM) and Building Information Modelling (BIM) are seen as innovations that can manage complexities in construction by focusing on integrating processes and products respectively. Whereas these two innovations have been considered compatible, their practical combination has been mainly anecdotal. The Netherlands was the locale of this study, where both SCM and BIM have been popular approaches. The research objective is to explore their real-world combination and propose strategies for the alignment of SCM and BIM, by viewing Supply Chain (SC) partnering as the inter-organisational proxy of SCM. The main question is: “How to align the SCM philosophy with BIM technologies to achieve integration in the construction industry? What aspects contribute to this alignment?”. The methodology was mixed and both qualitative and quantitative data were analysed. The overarching method was case study research and the unit of analysis was the firm, also referred to as ‘actor’.After a semi-chronological review of the relevant literature, the two constructs of SCM and BIM were found interdependent in product-, process-, and actor-related (P/P/A) dimensions. The study consisted of four other consecutive studies. First, empirical insights into the practical implementation of SC partnering and BIM were obtained via the exploration of five cases. Second, a conceptual model for the quantitative analysis of the product-, process-, and actor-related dimensions was designed. Third, this model and mixed methods were applied to two polar (extreme) cases to analyse the contractual (typically SC-related), digital (typically BIM-related), and informal interactions among the involved actors. Fourth, an additional theoretical exploration of the BIM-enabled SC partnerships took place with focusing also on intra-organisational relations within the involved firms. After the four studies, the findings were systematically combined to create the theoretical synthesis, i.e. generate theory. Three consecutive steps of ‘construct’, ‘internal’, and ‘external’ validity took place after the synthesis, to define the transferability of findings. The systematic combination of findings deduced two routes to achieve SC integration in construction: (a) product-related (emphasis on BIM tools), and (b) actor-related (emphasis on SCM philosophy).The two observed routes to SC integration emerged from the data of the polar cases. Two complementary sets of strategies for SC integration were derived afterwards. These strategies could ease the identification of which route is the ‘closest fit’ to SC integration, and then support the decision-making of how to pursue it. As the concept of BIM is currently a hot topic, it might be wise to undertake a ‘product-related’ route to integration and gradually introduce strategies from the ‘actor-related’ route. However, the ‘actor-related’ route could attain long-term integration and thus, long-lasting relations among the multi-actor networks. The key aspects of the alignment of partnering with construction IT for BIM-enabled SC partnerships are: - The identification of whether the SC complexity is of process-, product- or actor-related nature; - The deployed BIM collaboration patterns, i.e. ad-hoc, linear or distributed; - The SC coordination mechanisms, e.g. centralised or decentralised; - The relation between formal and informal aspects, e.g. symmetric or asymmetric; - The emerging intra-organisational relations due to BIM and SCM implementation; - The hierarchical level that BIM-enabled SC partnership decision-making pertains. As the construction industry evolves into an information-driven sector, the alignment of construction IT with inter-organisational management is preeminent for managing the inherent complexities of the industry. In parallel, embracing inter-organisational approaches for information management such as BIM is a promisingway forward for SCM and construction management

Alignment of Partnering with Construction IT: Exploration and Synthesis of network strategies to integrate BIM-enabled Supply Chains

Supply Chain Management (SCM) and Building Information Modelling (BIM) are seen as innovations that can manage complexities in construction by focusing on integrating processes and products respectively. Whereas these two innovations have been considered compatible, their practical combi-nation has been mainly anecdotal. The Netherlands was the locale of this study, where both SCM and BIM have been popular approaches. The research objective is to explore their real-world combination and propose strategies for the alignment of SCM and BIM, by viewing Supply Chain (SC) partnering as the inter-organisational proxy of SCM. The main question is: “How to align the SCM philosophy with BIM technologies to achieve integration in the construction industry? What aspects contribute to this alignment?â€. The methodology was mixed and both qualitative and quantitative data were analysed. The overarching method was case study research and the unit of analysis was the firm, also referred to as ‘actor’. After a semi-chronological review of the relevant literature, the two constructs of SCM and BIM were found interdependent in product-, process-, and actor-related (P/P/A) dimensions. The study consisted of four other consecutive studies. First, empirical insights into the practical implementation of SC partnering and BIM were obtained via the exploration of five cases. Second, a conceptual model for the quantitative analysis of the product-, process-, and actor-related dimensions was designed. Third, this model and mixed methods were applied to two polar (ex-treme) cases to analyse the contractual (typically SC-related), digital (typically BIM-related), and informal interactions among the involved actors. Fourth, an additional theoretical exploration of the BIM-enabled SC partnerships took place with focusing also on intra-organisational relations within the involved firms. After the four studies, the findings were systematically combined to cre-ate the theoretical synthesis, i.e. generate theory. Three consecutive steps of ‘construct’, ‘internal’, and ‘external’ validity took place after the synthesis, to define the transferability of findings. The systematic combination of findings deduced two routes to achieve SC integration in construction: (a) product-related (emphasis on BIM tools), and (b) actor-related (emphasis on SCM philosophy). The two observed routes to SC integration emerged from the data of the polar cases. Two com-plementary sets of strategies for SC integration were derived afterwards. These strategies could ease the identification of which route is the ‘closest fit’ to SC integration, and then support the decision-making of how to pursue it. As the concept of BIM is currently a hot topic, it might be wise to undertake a ‘product-related’ route to integration and gradually introduce strategies from the ‘actor-related’ route. However, the ‘actor-related’ route could attain long-term integration and thus, long-lasting relations among the multi-actor networks. The key aspects of the alignment of partnering with construction IT for BIM-enabled SC partnerships are: - The identification of whether the SC complexity is of process-, product- or actor-related nature;- The deployed BIM collaboration patterns, i.e. ad-hoc, linear or distributed;- The SC coordination mechanisms, e.g. centralised or decentralised;- The relation between formal and informal aspects, e.g. symmetric or asymmetric;- The emerging intra-organisational relations due to BIM and SCM implementation;- The hierarchical level that BIM-enabled SC partnership decision-making pertains. As the construction industry evolves into an information-driven sector, the alignment of construc-tion IT with inter-organisational management is preeminent for managing the inherent com-plexities of the industry. In parallel, embracing inter-organisational approaches for information management such as BIM is a promisingway forward for SCM and construction management

Dissemination and communication of lessons learned for a project-based business with the application of information technology: a case study with Siemens

With the recent development on a knowledge-based economy and project-based work, organizations gather and store their lessons and knowledge gained from projects to avoid ‘reinventing the wheel’ in future projects. To disseminate knowledge and experience at the group and organization levels, they further seek to develop a procedure to support project-based learning. This study conducts an in-depth case study in Siemens to investigate the perception of the individuals on barriers and enablers of implementing lessons learned. It also provides practical recommendations on how to enhance the dissemination of knowledge throughout the organization. The results of this study show that the retrieval of the information is a major barrier to lessons learned. To encourage more informal learning, organizations need to adopt various information communication systems and appropriate organizational culture and structure