Lars Taxén

Stochastic optimization in system design

The nonlinear optimization problem and statistical design problem can both be formulated as a region search problem. In this paper, we present a stochastic optimization process, suitable for optimizing functions of a certain measure over generalized regions in R^n . Conditions for an optimal process are discussed, and examples of a wide range of different optimization problems are given. These include the optimization of constrained, discontinuous and random functions in both discrete and continuous variable space. Design centering and tolerancing of large size systems subject to environmental disturbances are also treated.

Images as action instruments in complex projects

With the deregulation of the markets and the introduction of new technologies, the need to manage diversification, change and complexity in product development has become crucial. To cope with this situation an alternative foundation for PLM is needed in which social issues are considered alongside with more traditional, technical ones. Such a major re-orientation of PLM needs to be informed by a theoretical perspective, which integrates social and technical issues into a coherent sociotechnical framework. To this end we propose the Activity Domain Theory. This theory has been used as a guide at the Ericsson telecommunication company in order to suggest an alternative foundation for PLM. Preliminary results are the enhancement of the organisational language with the construct of activity domains, a clean-up of fundamental categories in information management, a multi-domain product structure concept, an alternative business process model, an information system managing core information elements and a strategy towards balancing centralised and decentralised control.

An integration centric approach for the coordination of distributed software development projects

This paper presents an approach for Distributed Software Development (DSD) that is based on two foundations. The first one is an integration centric engineering process, which aims at managing crucial dependencies in DSD projects. The second foundation is a strategy for operationalizing the coordination of the engineering process. The purpose of this strategy is to simultaneously provide global information system support for coordination and achieve common understanding about what should be coordinated and how. The approach has been successfully used at Ericsson, a major supplier of telecommunication systems worldwide, for coordinating extraordinary complex projects developing nodes in the third generation of mobile systems. Although many obstacles have to be addressed, the results indicate that the approach is a viable way to manage DSD during very demanding circumstances.

Manifesting shared affordances in system development : the system anatomy

With the deregulation of the markets and the introduction of new technologies, the need to manage diversification, change and complexity in product development has become crucial. To cope with this situation an alternative foundation for PLM is needed in which social issues are considered alongside with more traditional, technical ones. Such a major re-orientation of PLM needs to be informed by a theoretical perspective, which integrates social and technical issues into a coherent sociotechnical framework. To this end we propose the Activity Domain Theory. This theory has been used as a guide at the Ericsson telecommunication company in order to suggest an alternative foundation for PLM. Preliminary results are the enhancement of the organisational language with the construct of activity domains, a clean-up of fundamental categories in information management, a multi-domain product structure concept, an alternative business process model, an information system managing core information elements and a strategy towards balancing centralised and decentralised control.

Polyphase filter banks using wave digital filters

The branch filters in a digital polyphase network can be designed either as FIR filters by decomposing the impulse response of an FIR low-pass prototype filter, or as ordinary IIR filters by the synthesis method of Bellanger. The use of all-pass networks has hitherto been considered unfeasible because of the associated computational difficulties involved in the design of filter banks with many branches. The purpose of this paper is to demonstrate that it is indeed possible to design the branch filters as all-pass-low-pass sections without the need of a prototype filter. Moreover, these sections can be realized as wave digital filters, which give improved properties over the other designs with respect to hardware requirements, group delay, sensitivity, dynamics and limit cycles. Examples, including the design of the practically important 60-channel filter bank for the transmultiplexer, are given.

Using Activity Domain Theory for Managing Complex Systems

Latest research indicates that construction of a communal meaning regarding coordination of complex systems development tasks should be implemented into practice, proving that far more attention should be given to the issue of communal meaning construction in organizations. Using Activity Domain Theory for Managing Complex Systems offers a new approach towards managing the coordination of complex system development tasks that informs the co-construction of technical support for coordination and communal meaning regarding this support. Compiling and structuring empirical observations and theoretical developments from the perspective of meaning construction, this unique book combines a deep understanding of concrete, every-day conditions of the telecom industry with innovative theoretical development of the Activity Domain Theory.

Incremental development for AXE 10

To become more reactive and flexible to the market needs, i.e. shorter lead-times and more flexibility in handling late and changing requirements, Ericsson’s AXE 10 development processes have been adapted to support incremental development. The basic principle is to develop each of the customer features in one executable and testable increment. In order to plan, coordinate and control projects executed in this way, an Incremental Development Method Package, IDMP, has been developed by UAB in close cooperation with support groups in development projects. In this paper, we define what we mean with incremental development and describe the main aspects of the package. We also report experiences from using the package in the CMS 30 phase 7 and HELIOS projects. A prototype tool which supports the package is described, together with the experiences from using the tool in the pilot project Combined Gateway. Even if the IDMP has been developed towards AXE 10, it has proven useful in non AXE 10 projects, as the principles are rather independent of development process.

A sociotechnical approach towards alignment

In order to manage the complexity of the alignment problem, we introduce the construct of workpractices as the main unit of analysis. A workpractice is a meaningful, goal oriented social entity whe ...

Discrete optimization of digital filters using Gaussian adaptation and quadratic function minimization

In this paper, a new strategy for discrete optimization of a function F(x) is presented. Let A be the region in the n -dimensional parameter space, where F(x) is less than some constant. First, A is located and characterized by a Gaussian search process, called Gaussian adaptation. This makes it possible to approximate the behavior of F(x) . over A by a quadratic function Q(x) . Q(x) is then optimized for the N best discrete solutions using a branch and bound technique. Finally, these points are evaluated for the best F(x) points. By various digital filter examples it will be demonstrated that the new method is more capable of finding good solutions than methods presented so far.

The Activity Modalities: A Priori Categories of Coordination

A conceptualization of a-priori forms of coordination as activity modalities is proposed. Sensations in various sensory modalities are integrated by our brain into a coherent, actionable percept, structured by the processes of objectivation, contextualization, spatialization, temporalization, stabilization, and transition. This conceptualization promises to bridge neuroscientific and applied research into the coordination problem.