Designing sustainable work systems: The need for a systems approach

There is a growing discussion concerning sustainability. While this discussion was at first mainly focused on a society level – and sometimes regarding especially environmental problems, one can now see that this topic is of increasing relevance for companies worldwide and even the social dimension of this three pillar approach is gaining more and more importance. This leads to some questions: Is sustainability already a part of human factors thinking or do we have to further develop our discipline? How can we define sustainable work systems? What are the topics we have to consider? Do we need a new systems ergonomics perspective regarding whole value creation chains and a life-cycle perspective concerning products (and work systems)? How can we deal with potential contradictions about social, ecological, and economic goals?     

On Taylor series expansions for waiting times in tandem queues: an algorithm for calculating the coefficients and an investigation of the approximation error

Recently, a Taylor series expansion was developed for expected stationary waiting times in open (max,+)-linear stochastic systems with Poisson input process; these systems cover various instances of queueing networks.As an application, we present an algorithm for calculating the coefficients for infinite capacity tandem queueing networks with discrete service-time distributions. The algorithm works quite efficiently if the random vector of the service times of all servers is concentrated at a small number of atoms. We investigate the relative error of the Taylor approximation by simulation; in many cases, it follows very well a simple expression which holds exactly for independent, exponentially distributed servers.     

Anisotropic Filtering of Non-Linear Surface Features

A new method for noise removal of arbitrary surfaces meshes is presented which focuses on the preservation and sharpening of non‐linear geometric features such as curved surface regions and feature lines. Our method uses a prescribed mean curvature flow (PMC) for simplicial surfaces which is based on three new contributions: 1. the definition and efficient calculation of a discrete shape operator and principal curvature properties on simplicial surfaces that is fully consistent with the well‐known discrete mean curvature formula, 2. an anisotropic discrete mean curvature vector that combines the advantages of the mean curvature normal with the special anisotropic behaviour along feature lines of a surface, and 3. an anisotropic prescribed mean curvature flow which converges to surfaces with an estimated mean curvature distribution and with preserved non‐linear features. Additionally, the PMC flow prevents boundary shrinkage at constrained and free boundary segments.     

An information system architecture for build- and engineer-to-order production of application services

In manufacturing, substantial efficiency gains have been achieved through industrialization. Key concepts of industrialization include standardization, automation, and modularization. Transferring these to IT service production promises increased efficiency. ERP systems apply such concepts and have been an integrating tool for making production for manufacturers more efficient. However, previous research has considered ERP systems for IT service providers either very broadly or only from a business or technical perspective. This article investigates how to apply the ERP system concept comprehensively to a specific type of IT service provider. To this end, application services are prescribed as being composed of three types of configuration models. This helps to achieve a composition of (IT) application services that is comparable to physical parts, and it further supports their management and automated production within an ERP system. An information system architecture with the ERP system at its core is presented. It supports application service production. All relevant service lifecycle phases are considered and a consistent domain model is provided that connects business and technical layer entities. Targeted companies can improve their application service production in terms of quality and efficiency by leveraging this novel automation- and model-based approach.     

The Pathology of Cryptology—A Current Survey

Abstract

“The Pathology of Cryptology” is the title of a chapter in David Kahn's book The Codebreakers. This chapter mainly deals with hidden messages, which amateur scientists claim to have discovered in the works of William Shakespeare and in other literary works. The present article picks up this subject and provides it with a theoretic framework under the name of “para-steganography.” Moreover, further case studies are added to those given by Kahn, including many examples that only became known after the publication of The Codebreakers. These considerations show that a hidden code can be found almost anywhere, provided that one looks for it in a suitable manner.     

Holonic transport scheduling with teletruck

TELETRUCK is a multiagent-based dispatch support system developed in close collaboration with forwarders and transport engineers. The system supports dispatch officers in route planning, fleet management, and driver scheduling. TELETRUCK allows for dynamic planning and online optimization of transport orders based on an integration with modern telecommunication facilities. The TELETRUCK approach uses holonic agents, i.e., agents composed of subagents that act in a corporated way, in order to achieve a flexible, structured resource management in the planning process. A brief overview is given of the current implementation status of the TELETRUCK application prototype. Communication, coordination, and resource control distinguishing holonic from common multiagent systems are discussed. The underlying algorithms and protocols are described. Future extensions of the approach for intermodal and intercompany transport planning are discussed aiming at a smooth integration of modern transport and telecommunication networks.     

Coordinating distributed organizational knowledge

As organizations move from hierarchical towards market-like structures, their distributed units also take a larger role in the design and evolution of organizational information systems. This requires strategies which support the cooperative creation, evaluation and evolution of global information flow structures among autonomous organizational units through local knowledge acquisition and maintenance. Three such strategies are presented: cooperative conceptual modeling, multi-simulation, and explicit process support. These strategies are formally embedded in a meta modeling framework and implemented with a repository-based architecture. They are intended for the analysis of business processes in networked organizations, and as a basis for designing and evolving their federated information systems.     

Generating feature spaces for linear algorithms with regularized sparse kernel slow feature analysis

Without non-linear basis functions many problems can not be solved by linear algorithms. This article proposes a method to automatically construct such basis functions with slow feature analysis (SFA). Non-linear optimization of this unsupervised learning method generates an orthogonal basis on the unknown latent space for a given time series. In contrast to methods like PCA, SFA is thus well suited for techniques that make direct use of the latent space. Real-world time series can be complex, and current SFA algorithms are either not powerful enough or tend to over-fit. We make use of the kernel trick in combination with sparsification to develop a kernelized SFA algorithm which provides a powerful function class for large data sets. Sparsity is achieved by a novel matching pursuit approach that can be applied to other tasks as well. For small data sets, however, the kernel SFA approach leads to over-fitting and numerical instabilities. To enforce a stable solution, we introduce regularization to the SFA objective. We hypothesize that our algorithm generates a feature space that resembles a Fourier basis in the unknown space of latent variables underlying a given real-world time series. We evaluate this hypothesis at the example of a vowel classification task in comparison to sparse kernel PCA. Our results show excellent classification accuracy and demonstrate the superiority of kernel SFA over kernel PCA in encoding latent variables.     

On aspectualizing component models

Server‐side component models such as Enterprise JavaBeans (EJB) add powerful abstractions to the bare ‘business objects’ layer in order to support a clean separation of server‐side application logic from other concerns such as distribution, security, transaction management and persistence. An improved separation of concerns is also the main goal of aspect‐oriented programming (AOP). This paper compares the two approaches and reasons about the possibility of substituting (parts of) component models using AOP mechanisms. We conclude that AOP is a promising approach to eliminate important shortcomings of the container‐based component approach. However, our analysis of concrete aspect‐oriented languages shows that current AOP technology is not yet mature enough to supersede component models. Copyright © 2003 John Wiley & Sons, Ltd.