Flexible Relations - Operational Support of Variant Relational Struetures

The relational model is accepted for its simplicity and eIegance. At the other side the simplicity causes the problem, that most semantic type constructs are not representable as a simple relation. Variant and heterogeneous structures belong to those constructs not adequatly supported by the simple relational model. In this paper we give an overview of the model of flexible relations that allows to model and process arbitrary heterogeneous structures, while preserving the relational philosophy of operating with a single constructor. As flexible relations support both the modeling and the operational aspect of variant structures seamlessly, our model truly helps to further bridge the gap between semantic and operational data models. We discuss the structural part of the moQ.el and introduce an algebra for flexible relations. Further we examine a subdass of flexible relations, that can be processed as efficiently as the simple relational model, and show that this subdass possesses desirable structural normal form properties. In addition, we point out that our approach exceeds the objectoriented paradigm in modeling power, typing precision, and query optimization potential

Inference Optimization using Relational Algebra

Exact inference procedures in Bayesian networks can be expressed using relational algebra; this provides a common ground for optimizations from the AI and database communities. Specifically, the ability to accomodate sparse representations of probability distributions opens up the way to optimize for their cardinality instead of the dimensionality; we apply this in a sensor data model.\u

Record Subtyping in Flexible Relations by means of Attribute Dependencies

The model of flexible relations supports heterogeneous sets of tuples in a strongly typed way. The elegance of the standard relational model is preserved by using a single, generic scheme constructor.In each model supporting structural variants the shape of some part of a heterogeneous scheme may be determined by the contents of some other part of the scheme. We formalize this relationship by a certain kind of integrity constraint we have called "attribute dependency" (AD). We motivate how ADs can be used, besides their application in type and integrity checking, to incorporate record subtyping into our extended relational model Moreover, we show that ADs yield a stronger assertion than the traditional record subtyping rule as they consider interdependencies among refinements. We discuss how ADs are related to query processing and how they may help to identify redundant operations

Management control of supplier relationships in manufacturing: a case study in the automotive industry.

This paper studies management control design of supplier relationships in manufacturing, a supply chain phase currently under-explored. Compared to supplier relations during procurement and R&D, which research found to be governed by a combination of formal and informal controls, supplier relations in manufacturing are more formal, so that they could be governed by more formal and less informal controls. To refine the management control system and influencing contingencies, we propose a theoretical framework specifically adapted for the manufacturing stage. This framework is investigated by an in depth case study of the supplier management control of a Volvo Cars production facility. We identify three types of suppliers visualizing the associations in the framework and illustrating the framework’s explicative power in (automotive) manufacturing. Furthermore, the case contradicts that supplier relations in the manufacturing phase are governed by little informal control, because the automaker highly values the role of trust building and social pressure. Most notably, a structured supplier team functions as a clan and establishes informal control among participating suppliers, which strengthens the automaker’s control on dyadic supplier relations.management control; supplier relationships; manufacturing; contingency theory; case research;

Incorporating record subtyping into a relational data model

Most of the current proposals for new data models support the construction of heterogeneous sets. One of the major challenges for such data models is to provide strong typing in the presence of heterogenity. Therefore the inclusion of as much as possible information concerning legal structural variants is needed. We argue that the shape of some part of a heterogeneous scheme is often determined by the contents of some other part of the scheme. This relationship can be formalized by a certain type of integrity constraint we have called attribute dependency. Attribute dependencies combine the expressive power of general sums with a notation that fits into relational models. We show that attribute dependencies can be used, besides their application in type and integrity checking, to incorporate record subtyping into a relational model. Moreover, the notion of attribute dependency yields a stronger assertion than the traditional record subtyping rule as it considers some refinements to be caused by others. To examine the differences between attribute dependencies and traditional record subtyping and to be able to predict how attribute dependencies behave under transformations like query language operations we develop an axiom system for their derivation and prove it to be sound and complete. We further investigate the interaction between functional and attribute dependencies and examine an extended axiom system capturing both forms of dependencies

Information Technology as Coordination Infrastructure

Business information technology is traditionally viewed as information provision technology. In this view, organizations use their IT to implement databases that provide people with information when they want it. This view is persistent even though information provision is never an end in itself but always has the further purpose to support the coordination of activities of people. The role if IT as coordination technology became more prominent in the 1980s with the advent of network technology, that allowed activities across different businesses to be coordinated. This trend has accellerated since the growth of Internet usage, and today IT is used to support an increasingly varied range of processes performed by a variety of partners that do not all have a hierarchical relation to each other. This makes it difficult to analyze requirements for IT support and specify IT solutions: Business processes may not be well-defined, and interests of different businesses may clash. This report argues that to deal with this in requirements engineering and IT solution specification, business information technology should not be viewed as IT support for business processes but as IT support for the coordination of activities in one or more businesses. We will identify three basic coordination mechanisms, namely coordination by price, by management, and by shared norms, and for each of these mechanisms, we will identify requirements for IT support. The advent of flexible and standardized networking technology has facilitated the creation of novel coordination mechanisms within these three general paradigms, and we will give an inventory of generalized coordination mechanisms made possible by current IT. Finally, we will draw conclusions for requirements engineering methods for IT support for each of the coordination mechanisms identified by the framework

Banks, knowledge and crisis: a case of knowledge and learning failure

Purpose – Regulators such as Turner have identified excessive securitization, high leverage, extensive market trading and a bonus culture, as being major factors in bringing about the bank centred financial crisis of 2007-2009. Whilst it is inevitable that banks adopt procyclical business strategies, not all banks took excessive risks and subsequently had to be rescued by taxpayers. The paper examines the extent to which individual bank outcomes can be attributed to systematic differences in banking knowledge concerning the primary risks and value drivers of their organisations by bank board directors and top management. Design/methodology/approach – The paper reviews a wide range of theoretical, historical and empirical literatures on banking models and detailed case analyses of failing and non-failing banks. A framework for understanding the role and application of knowledge in banking is developed which suggests how banks, despite their pro-cyclical business strategies, are able to institutionalise learning and actively create new knowledge through time to improve bank organisation, intermediation and risk management. Findings – The paper finds that a lack of basic knowledge of banking risks and value drivers by the boards and senior managers of the failing banks were implicated in the banking crisis. These knowledge problems concerned banks' understanding of their organisation, intermediation and risk management in an active market setting characterised by rapid economic and organisational change. Thus, the failing banks ignored or were unaware of this knowledge and hence experienced acute difficulties with learning the new knowledge needed to address the new problems thrown-up by the financial crisis. Practical implications – The analysis suggests that addressing this knowledge gap via the institutionalisation of banking knowledge ought to constitute an important element of any sustainable solution to the problems currently being experienced by the banking sector. By ensuring greater bank learning, knowledge creation, and knowledge use, governments and regulators could help reduce individual bank risk and the likelihood of future crisis. Originality/value – In contrast to the claims made by some politicians and banking insiders, the analysis indicates that the banking crisis and its severity were neither unpredictable nor unavoidable since some banks, by institutionalising banking knowledge and history of past crises, successfully avoided the pitfalls experienced by the failing banks