Continuous Time Matching Constraints for Image Streams

Corresponding image points of a rigid object in a discrete sequence of images fulfil the so-called multilinear constraint. In this paper the continuous time analogue of this constraint, for a continuous stream of images, is introduced and studied. The constraint links the Taylor series expansion of the motion of the image points with the Taylor series expansion of the relative motion and orientation between the object and the camera. The analysis is done both for calibrated and uncalibrated cameras. Two simplifications are also presented for the uncalibrated camera case. One simplification is made using an affine reduction and the so-called kinetic depths. The second simplification is based upon a projective reduction with respect to the image of a planar configuration. The analysis shows that the constraint involving second-order derivatives are needed to determine camera motion. Experiments with real and simulated data are also presented.     

Internet computing as a disruptive information technology innovation: the role of strong order effects1

A cross‐sector survey study was conducted between 2004 and 2005 among 121 software firms that adopted internet computing for the presence of strong order effects, which explain how, why and in which order radical innovations in information system (IS) are adopted. The following strong order effects were detected: (1) the amount of base innovations positively and directly influenced the amount of service innovation and the amount of process innovation, while the amount of service innovation partially mediates the impact of base innovation on process innovation; (2) the radicalness of base innovations directly and positively influences the radicalness of service innovation, while the impact of the radicalness of the base innovation on the radicalness of process innovations is fully mediated by the radicalness of service innovation; (3) the predominant sequence of initial adoption of radical information technology innovations is first in base innovations, followed by service innovations and finally by process innovations. Our study helps to better understand how and why radical innovations are adopted in ensembles by software firms. In consequence, software organizations should orchestrate flexible innovation strategies that recognize that radical innovations are interconnected and heterogeneous.     

Digital product innovation within four classes of innovation networks

The increased digitization of organizational processes and products poses new challenges for understanding product innovation. It also opens new horizons for information systems research. We analyse how ongoing pervasive digitization of product innovation reshapes knowledge creation and sharing in innovation networks. We argue that advances in digital technologies (1) increase innovation network connectivity by reducing communication costs and increasing its reach and scope and (2) increase the speed and scope of digital convergence, which increases network knowledge heterogeneity and need for integration. These developments, in turn, stretch existing innovation networks by redistributing control and increasing the demand for knowledge coordination across time and space presenting novel challenges for knowledge creation, assimilation and integration. Based on this foundation, we distinguish four types of emerging innovation networks supported by digitalization: (1) project innovation networks; (2) clan innovation networks; (3) federated innovation networks; and (4) anarchic innovation networks. Each network involves different cognitive and social translations – or ways of identifying, sharing and assimilating knowledge. We describe the role of five novel properties of digital infrastructures in supporting each type of innovation network: representational flexibility, semantic coherence, temporal and spatial traceability, knowledge brokering and linguistic calibration. We identify several implications for future innovation research. In particular, we focus on the emergence of anarchic network forms that follow full‐fledged digital convergence founded on richer innovation ontologies and epistemologies calling to critically re‐examine the nature and impact of modularization for innovation.     

Fabrication of thermal microbridge actuators and characterization of their electrical and mechanical responses

This study presents thermal silicon microbridge actuators which have been made by a novel fabrication process utilizing dry processes for all critical steps. The fabrication process results in microbridges which are fully oxide covered, with excellent surface quality and dimensional control. The microbridges are made in the device layer of a silicon-on-insulator (SOI) wafer which ensures uniform doping profile and accurate thickness control. The electrical and mechanical responses of the bridges were measured upon rapid heating up to near the melting point of silicon. Up to 12 μm mechanical deflection due to thermal expansion was detected by white light interferometry (WLI) which allowed accurate measurement. Mechanical deflection has previously not been measured for silicon microlamps. Thermal conduction in the air gap between the actuator and the neighbouring solid silicon parts was analysed and shown to be more important than convection or radiation, even at very high operation temperatures.     

Time and information technology in teams: a review of empirical research and future research directions

Information technology (IT) is intricately bound up with time in teams. Yet a comprehensive review of what is known about time in IT-mediated teams is lacking. This paper addresses this gap. We classify time into three categories: conceptions of time, mapping activities to time, and actors relating to time. Drawing upon this framework, we review empirical information systems (IS) research on IT-mediated teams over the past three decades. Our review reveals that the research has approached time predominantly using the clock view and has examined exclusively how to map a single activity to the continuum of time. As a result, most studies operate within a simplified temporal context by conceiving time as an objective attribute that ticks away. Meanwhile, a void exists in research that recognizes time as interpretive and experienced. Our analyses also indicate that past research has been primarily interested in the differences between face-to-face and IT-mediated teams and the communication function of IT. Overall, IT remains roughly conceptualized, and research has produced fragmented insights that have small cumulative effects. To advance more substantive theory building, we propose several research directions that invite richer theorizing about how IT is related to time in teams.     

Innovation among different classes of software development organizations

Software development organizations (SDOs) innovate in diverse ways. In this paper, based on an extensive review of innovation typologies, we develop a theory‐driven typology of SDO innovator classes. We theorize about the driving forces behind these classes, with specific attention given to knowledge‐based dispositions that relate to the SDO's knowledge‐based competencies in technology appropriation, technology generation, and network intensity within ecological niches. Through a survey of 136 SDOs, which adopted Internet technologies during 1995‐2006, we empirically verify that these classes also determine different ways that SDOs innovate around software services they provide to their clients. Our findings suggest that the knowledge‐based dispositions of different SDO innovator classes impact how they innovate. Overall, the study involves theorizing around different types of innovation behaviours and associated knowledge‐based factors that influence the way SDOs innovate.     

Weakly coprime factorization and state-feedback stabilization of discrete-time systems

The LQ-optimal state feedback of a finite-dimensional linear time-invariant system determines a coprime factorization NM ⁻¹ of the transfer function. We show that the same is true also for infinite-dimensional systems over arbitrary Hilbert spaces, in the sense that the factorization is weakly coprime, i.e., Nf, for every function f. The factorization need not be Bézout coprime. We prove that every proper quotient of two bounded holomorphic operator-valued functions can be presented as the quotient of two bounded holomorphic weakly coprime functions. This result was already known for matrix-valued functions with the classical definition gcd(N, M) = I, which we prove equivalent to our definition. We give necessary and sufficient conditions and further results for weak coprimeness and for Bézout coprimeness. We then establish a variant of the inner–outer factorization with the inner factor being “weakly left-invertible”. Most of our results hold also for continuous-time systems and many are new also in the scalar-valued case.     

Explaining information systems change: a punctuated socio-technical change model

We outline a Punctuated Socio-Technical Information System Change model. The model recognizes both incremental and punctuated socio-technical change in the context of information systems at multiple levels – the work system level, the building system level, and the organizational environment. It uses socio-technical event sequences and their properties to explain how a change outcome emerged. The critical events in these sequences correspond to gaps in socio-technical systems. By conceiving information system (IS) change as a multi-level and punctuated sequence of socio-technical events, IS researchers can conceive plausible and accurate process explanations of IS change outcomes, including IS failures. Such explanations are located in the middle range and thus avoid the highly abstract and stylized closed-boxed factor models of change, but go beyond the idiographic open box histories of singular change processes.     

Automatic geometric reasoning in structure and motion estimation

We present a system for doing automatic surveying or structure and motion analysis given 1D images of a 2D surrounding. Nothing is known about the structure of the scene features or of the motion of the camera. The system automatically identifies and tracks the image of new points and solves the structure and motion problem. One key feature of the system is the ability to hypothesize, test and incorporate simple constraints on the scene, e.g. that two object points are the same, that several points are coplanar. In this paper we develop and test the theory for automatic geometric reasoning. Ideas on hypothesis generation and testing are presented. It is also shown how to update the uncertainty representation of the database.     

Early vs. late adoption of radical information technology innovations across software development organizations: an extension of the disruptive information technology innovation model

This paper extends the disruptive information technology innovation model (DITIM) by exploring the impact of adoption timing on innovation outcomes within software development organizations during a disruptive innovation cycle. The DITIM suggests that radical changes in computing platforms result in pervasive and radical innovations in software development organizations across three innovation types: base technologies adopted, services produced and processes adopted. Upstream attributes (amount and radicalness) of the base innovations impact effects in‐kind downstream (a.k.a., strong order effects) on services and processes. Extending these tenets of the DITIM, we posit that during disruptive information technology (IT) innovation, the temporal stage of innovation activity (early vs. late) by software development organizations will significantly impact four innovation characteristics: (1) adoption rate of radical IT innovations, (2) strong order effects on downstream innovations related to the amount of innovation, (3) perceived radicalness of innovations and (4) strong order effects on downstream innovations related to the amount of perceived radicalness of innovation. We examine these impacts by reanalysing a cross‐sectional study of 121 software development organizations that adopted internet computing as reported in the original data analysis of the DITIM. By splitting the data into early and late adopter groups, our moderation analysis shows significant differences between early and late adopting groups in each of the four hypothesized impacts. Specifically, the adoption rate of radical IT innovations, strong order effects on the amount of innovation, perceived radicalness of innovations and strong order effects on perceived radicalness were each found to differ between early and late adopters. However, it is also important to consider innovation type as three significant effects were in the opposite direction for process innovations. These findings suggest that IT‐innovation scholars and practitioners should carefully consider innovation timing and type when studying or managing radical IT innovation.