Scattering in one dimension: The coupled Schroedinger equation, threshold behaviour and Levinson's theorem

We formulate scattering in one dimension due to the coupled Schr\"{o}dinger equation in terms of the $S$ matrix, the unitarity of which leads to constraints on the scattering amplitudes. Levinson's theorem is seen to have the form $\eta(0) = \pi (n_b + 1/2 n - 1/2 N)$, where $\eta(0)$ is the phase of the $S$ matrix at zero energy, $n_b$ the number of bound states with nonzero binding energy, $n$ the number of half-bound states, and $N$ the number of coupled equations. In view of the effects due to the half-bound states, the threshold behaviour of the scattering amplitudes is investigated in general, and is also illustrated by means of particular potential models.Comment: to appear in Journal of Mathematic Physics, RevTex, 16 pages, 3 figures (PostScript

Success and failure factors in ICT projects: a Dutch perspective.

This thesis examines the success and failure factors in ICT projects. The low success rate of software projects in terms of reliability, meeting due dates and working within assigned budgets is widely recognised and topical. International as well as Dutch publications and the procedures in Tarek Abdel-Hamid's work on Software Project Management/Dynamics are discussed. A SUFFI Chart (SUFFI = SUccess and Failure Factors in ICT projects) is developed. The management of a portfolio of projects is compared with the SUFFI Chart. A number of Dutch projects with which the author was directly involved are examnined to show how they compare with the factors identified from the literature. These do show considerable correlation between important SUFFI factors and project success. The portfolio consists of nine ICT projects and four ICT project audits. Projects such as SAP, RBAC, EAI, charging method, PABX, financial building adrnmistration, information retrieval, book reservations, traffic data collection, introduction of the Internet functionality and SOX, for different companies/organisations (Delft University of Technology, National Police Services Agency, KPN - Dutch Telecom Company, University of Amsterdam, government, banking). This work shows that for a successful project 4 of the 5 most important SUFFIs have to be absent

Modeling regional house prices

We develop a parsimonious panel model for quarterly regional house prices, for which both the cross-section and the time series dimension is large. The model allows for stochastic trends, cointegration, cross-equation correlations and, most importantly, latent-class clustering of regions. Class membership is fully data-driven and based on (i) average growth rates of house prices, (ii) the propagation of shocks to house prices across regions, also known as the ripple effect, and (iii) the relationship of house prices with economic growth and other variables. Applying the model to quarterly data for the Netherlands, we find convincing evidence for the existence of two distinct clusters of regions, with pronounced differences in house price dynamics.cointegration;ripple effect;cross-section dependence

Determinants of Leverage and Agency problems

In this paper we empirically investigate the determinants of leverage and agency problems and we examine the relationships between leverage and agency problems. As in Titman and Wessels (1988) we use structural equations modeling with latent variables. In contrast to Titman and Wessels (1988), who employ data obtained from annual reports and capital markets, we use questionnaire data to measure firm characteristics. The questions concern the characteristics of the respondents’ firms, including the presence of agency problems. We estimate the relations between these characteristics. The results confirm that the trade-off between tax advantages and bankruptcy costs determines leverage. We also find free cash flow and corporate governance characteristics as determinants of overinvestment. Despite findings that agency problems are present, direct relationships between leverage and four agency problems are absent.capital structure;agency costs

Surface Modification of a PCB Substrate for Better Adhesion of Inkjet Printed Circuit Structures

The robustness and service life of inkjet printed electronic circuit structures are highly influenced by the state of the interface between these structures and the substrate. In the case of polymeric substrate materials, surface modification is necessary to realise a favourable interface, as these materials are generally not very receptive to chemical bond formation with the deposited ink. This paper deals with the surface modification of a high frequency laminate (substrate) using two different techniques to improve interfacial adhesion. The techniques deployed are CF4/O2 based plasma treatment and micro structuring using pulsed laser. The plasma treatment parameters were varied systematically using a statistical design of experiments. Substrates with varying surface characteristics, resulting from different plasma treatment parameters, were subjected to post-processing steps including surface energy and surface roughness measurements. Similarly, the influence of laser treatment parameters on surface characteristics of the substrate was also studied in detail. The outcomes of these two surface modification techniques are discussed in this paper

Specification Techniques for Multi-Modal Dialogues in the U-Wish Project

In this paper we describe the development of a specification\ud technique for specifying interactive web-based services. We\ud wanted to design a language that can be a means of\ud communication between designers and developers of interactive services, that makes it easier to develop web-based services fitted to the users and that shortens the pathway from design to implementation. The language, still under development, is based on process algebra and can be\ud connected to the results of task analysis. We have been\ud working on the automatic generation of executable prototypes\ud out of the specifications. In this way the specification\ud language can establish a connection between users, design\ud and implementation. A first version of this language is\ud available as well as prototype tools for executing the specifications. Ideas will be given as to how to make the connection between specifications and task analysis

A comparative study of two conductive inkjet inks for fabrication of RF circuit structures

Two commercially available silver inks were inkjet printed to fabricate the seed tracks (seed layers) of radio frequency (RF) circuit structures on a high frequency substrate material. One of them is a nanoparticle based ink, and the other, a non-particle based organic silver complex ink. Subsequent to printing, these seed layers were copper plated using an electroless copper plating process, to impart the desired thickness to the circuit structures. The inkjet printing-electroless plating process combination was validated with the example of an S-band filter and an RF transmission line. Prior to the fabrication of the circuit structures, the substrates were plasma treated, in order to modify their surface and promote mechanical interlocking with the printed structures.\ud Finally, experiments were conducted to determine the solderability\ud of inkjet printed as well as printed-plated structures. Conclusions on\ud the suitability of the two inks for RF circuit fabrication have been\ud drawn based on experimental results

Maps, agents and dialogue for exploring a virtual world

In previous years we have been involved in several projects in which users (or visitors) had to find their way in information-rich virtual environments. 'Information-rich' means that the users do not know beforehand what is available in the environment, where to go in the environment to find the information and, moreover, users or visitors do not necessarily know exactly what they are looking for. Information-rich means also that the information may change during time. A second visit to the same environment will require different behavior of the visitor in order for him or her to obtain similar information than was available during a previous visit. In this paper we report about two projects and discuss our attempts to generalize from the different approaches and application domains to obtain a library of methods and tools to design and implement intelligent agents that inhabit virtual environments and where the agents support the navigation of the user/visitor

Industrial Policy and Technology Diffusion: Evidence from Paper Making Machinery in Indonesia

technology diffusion, Indonesia

Channels, consumers and communication: online and offline communication in service consumption

This paper reports on a study that investigated consumer use of e-services in a multichannel context. To develop a deeper understanding of what makes consumers decide to use the online channel, and contrary to most HCI studies on the use of e-services that focus on the use of the online channel in relative isolation, this study examined consumer channel-choice beyond the instances of internet use. The consumption behaviour of its participants was investigated across channels in an in-depth qualitative study. The analysis of the elicited rich data focused specifically on the investigation of voluntary consumer movements between online and offline channels during the course of a consumption process. The results indicate that participants often use multiple channels in parallel and frequently switch between channels. Literature from marketing and consumer research was used as the perspective to explore the rationale for the complex and dynamic reported consumer behaviour