Michaela Denk

Competence-driven project portfolio selection, scheduling and staff assignment

This paper presents a new model for project portfolio selection, paying specific attention to competence development. The model seeks to maximize a weighted average of economic gains from projects and strategic gains from the increment of desirable competencies. As a sub-problem, scheduling and staff assignment for a candidate set of selected projects must also be optimized. We provide a nonlinear mixed-integer program formulation for the overall problem, and then propose heuristic solution techniques composed of (1) a greedy heuristic for the scheduling and staff assignment part, and (2) two (alternative) metaheuristics for the project selection part. The paper outlines experimental results on a real-world application provided by the E-Commerce Competence Center Austria and, for a slightly simplified instance, presents comparisons with the exact solution computed by CPLEX.

Multi-objective decision analysis for competence-oriented project portfolio selection

This paper develops a multi-objective optimization model for project portfolio selection taking employee competencies and their evolution into account. The objectives can include economic gains as well as gains expressed in terms of aggregated competence increments according to pre-defined profiles. In order to determine Pareto-optimal solutions, the overall problem is decomposed into a master problem addressing the portfolio selection itself, and a slave problem dealing with a suitable assignment of personnel to the work packages of the selected projects over time. We provide an asymptotic approximation of the problem by a linearized formulation, which allows an efficient and exact solution of the slave problem. For the solution of the master problem, we compare the multi-objective metaheuristics NSGA-II and P-ACO. Experimental results both for synthetically generated test instances and for real-world test instances, based on an application case from the E-Commerce Competence Center Austria, are presented.

Carbocyanine Postmortem Neuronal Tracing: Influence of Different Parameters on Tracing Distance and Combination with Immunocytochemistry

SUMMARY Carbocyanines (DiI, DiA, DiO) are able to travel along membranes by diffusion and therefore have been used as postmortem neuronal tracers in aldehyde-fixed tissues. Surprisingly, detailed data on the influence of different parameters on tracing distances are still missing. This study was carried out to optimize tracing procedures and to reveal the validity of the combination of postmortem tracing with immunocytochemistry. Carbocyanine crystals were applied to the cervical spinal cord, sciatic nerves, and brachial plexuses of humans and guinea pigs. Incubation in the dark at 37C for 12-15 weeks proved optimal to achieve longest tracing distances (28.9 ± 2.2 mm) in human and animal tissues. Longer incubation times and incubation temperatures higher than 37C did not result in longer tracing distances. No differences were evident between adult and newborn animals and between central and peripheral nervous system. The diffusion coefficient for DiI was calculated to be 2.5 × 10-7 cm2sec-1. After application of DiI to nerves of guinea pig extraocular muscles, DiI-positive afferent perikarya were observed in the anteromedial part of the trigeminal ganglion. These perikarya were identified by calcitonin gene-related peptide immunoreactivity (CGRP-IR). The percentage of CGRP-IR neurons after tracing was concordant with the percentage of CGRP-IR in trigeminal ganglia exclusively processed for CGRP-IR without previous postmortem tracing. These results demonstrate carbocyanines to be specific tracers for exact neuronal mapping studies.

The Effectiveness of Combining Online and Print Advertisements: Is the Whole Better than the Individual Parts?

ABSTRACT Cross-media advertising has received wide attention from practitioners over the last years, but there are only few experimental studies that analyze the effectiveness of integrating online and print advertising. Contributing to this relevant research field, this article analyzes advertising effectiveness of print and online media as well as the impact of combining these two media forms on overall advertising effectiveness. Our study supports existing findings that print and online advertising feature the same advertising effectiveness. Our experimental data, however, also indicate advantages of cross-media advertising.

Mobile learning challenges and potentials

The transition to an information society and the therewith strongly related need of lifelong and life-wide learning on the one hand, and the increasing coverage of and developments in mobile information and communication technology on the other hand establish the foundation of mobile learning. This paper discusses the challenges and potentials of the present mobile learning trend from a broad perspective. Going back to the primal origins of learning, it reviews mobile learning as well as related concepts and definitions and investigates requirements, potential barriers and benefits of mobile learning. Eventually, promising mobile learning applications are examined and a future empirical study is outlined.

Two fibromuscular transverse ligaments related to the levator palpebrae superioris: Whitnall's ligament and an intermuscular transverse ligament.

This study was performed to reinvestigate the detailed anatomy of the connective tissues related to the levator palpebrae superioris (LPS).

Sensory innervation of the guinea pig extraocular muscles: A 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate tracing and calcitonin gene-related peptide immunohistochemical study

The sensory apparatus of the extraocular muscles attains special interest because of the great variation among different species with respect to the proprioceptors. The sensory innervation of the guinea pig extraocular muscles, lacking both muscle spindles and tendon organs, was investigated with a fluorescence double‐labelling method. Primary sensory perikarya were assessed by postmortem application of 1,1′‐dioctadecyl‐3,3,3′3′‐tetramethylindocarbocyanine perchlorate (Di‐I) to the extraocular muscle nerves. Traced neurons were found in the ipsilateral ophthalmic part of the trigeminal ganglion. This is in line with findings in other species. Calcitonin gene‐related peptide (CGRP) was detected immunohistochemically within the trigeminal ganglion. No somatotopic organization was observed for CGRP‐like immunoreactive perikarya. Small (maximal diameter below 30 μm), medium (maximal diameter between 30 and 50 μm), and large (maximal diameter larger than 50 μm) trigeminal ganglion cells were found among the primary afferent perikarya from extraocular muscles. Among CGRP‐like immunoreactive cells, only small and medium cells were observed. Double‐labelling experiments indicated the CGRP content of primary afferents of the guinea pig extraocular muscles. The relationship to former morphological categories of ganglion cells is discussed. Primary afferent neurons with CGRP‐like immunoreactivity might have efferent functions and might also be involved in inflammatory processes of extraocular muscles. J. Comp. Neuol. 380:16–22, 1997.

Avoid Filling Swiss Cheese with Whipped Cream; Imputation Techniques and Evaluation Procedures for Cross-Country Time Series

International organizations collect data from national authorities to create multivariate cross-sectional time series for their analyses. As data from countries with not yet well-established statistical systems may be incomplete, the bridging of data gaps is a crucial challenge. This paper investigates data structures and missing data patterns in the cross-sectional time series framework, reviews missing value imputation techniques used for micro data in official statistics, and discusses their applicability to cross-sectional time series. It presents statistical methods and quality indicators that enable the (comparative) evaluation of imputation processes and completed datasets.

Statistical composites: a transformation-bound representation of statistical datasets

Statistical data processing makes use of data matrices and tables as primary structures for data representation. Embedding these structures into processing-relevant context information gives rise to enhanced data structures linking data and metadata. The paper describes a framework for statistical data processing utilising metadata computationally.

Where does mobile business go

Understanding the business and commercial intricacies of mobile commerce is not easy. Different actors are involved and they all aim at providing users with new data and services through their mobile devices. Moreover, mobile business differs substantially from known online business, due to better user reachability and higher identification with mobile devices. MB-net, a thematic network funded by the European Commission, investigates business and commercial prospects of mobile applications and services, to highlight the topics on which international research should focus during the next years. The findings of this network and the current status of the strategic research roadmap developed are summarised and further elaborated in this paper. In order to get insight into the current situation, the potential development and the key issues of mobile commerce in Austria, an expert survey was conducted for the occasion of the first Austrian MB-net workshop in November 2002. The key findings of the survey are presented in the paper and put into the context of the research roadmap.