231 research outputs found

    An analysis of configurations of relationship quality dimensions to explain sources of behavioral outcomes in globalized manufacturing

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    Purpose This paper aims to explore the role of configurations of relationship quality dimensions for explaining sources of behavioral outcomes in the globalized manufacturing industry. Design/methodology/approach A joint analysis of behavioral and objective performance data from globalized manufacturing links perceptual customer metrics that relate to dimensions of relationship quality (i.e. attitudinal loyalty, perceived customer orientation, customers’ perceived innovativeness of the supplier and perceived customer influence on supplier innovation) with behavioral outcomes (i.e. share of wallet (SOW) and customer account profitability). Using data from a global business-to-business (B2B) customer survey together with archival performance data from a multinational mechanical engineering firm, a fuzzy set qualitative comparative analysis (fsQCA) is performed.Peer reviewe

    Structures and Algorithms for Peer-to-Peer Cooperation

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    Peer-to-peer overlay networks are distributed systems, without any hierarchical organization or centralized control. Peers form self-organizing overlay networks that are on top of the Internet. Both parts of this thesis deal with peer-to-peer overlay networks, the first part with unstructured ones used to build a large scale Networked Virtual Environment. The second part gives insights on how the users of a real life structured peer-to-peer network behave, and how well the proposed algorithms for publishing and retrieving data work. Moreover we analyze the security (holes) in such a system. Networked virtual environments (NVEs), also known as distributed virtual environments, are computer-generated, synthetic worlds that allow simultaneous interactions of multiple participants. Many efforts have been made to allow people to interact in realistic virtual environments, resulting in the recent boom of Massively Multiplayer Online Games. In the first part of the thesis, we present a complete study of an augmented Delaunay-based overlay for peer-to-peer shared virtual worlds. We design an overlay network matching the Delaunay triangulation of the participating peers in a generalized d-dimensional space. Especially, we describe the self-organizing algorithms for peer insertion and deletion. To reduce the delay penalty of overlay routing, we propose to augment each node of the Delaunay-based overlay with a limited number of carefully selected shortcut links creating a small-world. We show that a small number of shortcuts is sufficient to significantly decrease the delay of routing in the space. We present a distributed algorithm for the clustering of peers. The algorithm is dynamic in the sense that whenever a peer joins or leaves the NVE, the clustering will be adapted if necessary by either splitting a cluster or merging clusters. The main idea of the algorithm is to classify links between adjacent peers into short intracluster and long inter-cluster links. In a structured system, the neighbor relationship between peers and data locations is strictly defined. Searching in such systems is therefore determined by the particular network architecture. Among the strictly structured systems, some implement a distributed hash table (DHT) using different data structures. DHTs have been actively studied in the literature and many different proposals have been made on how to organize peers in a DHT. However, very few DHTs have been implemented in real systems and deployed on a large scale. One exception is KAD, a DHT based on Kademlia, which is part of eDonkey, a peer-to-peer file sharing system with several million simultaneous users. In the second part of this thesis we give a detailed background on KAD, the organization of the peers, the search and the publish operations, and we describe our measurement methodology. We have been crawling KAD continuously for more than a year. We obtained information about geographical distribution of peers, session times, peer availability, and peer lifetime. We found that session times are Weibull distributed and show how this information can be exploited to make the publishing mechanism much more efficient. As we have been studying KAD over the course of the last two years we have been both, fascinated and frightened by the possibilities KAD offers. We show that mounting a Sybil attack is very easy in KAD and allows to compromise the privacy of KAD users, to compromise the correct operation of the key lookup and to mount distributed denial-of-service attacks with very little resources

    Biobarometer Schweiz 2020 –Teil 1

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    Biobarometer Schweiz 2020 –Teil 1 Ausführliche Foliensammlung der Ergebnisse

    Variability of doublecortin-associated dendrite maturation in adult hippocampal neurogenesis is independent of the regulation of precursor cell proliferation

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    BACKGROUND: In the course of adult hippocampal neurogenesis most regulation takes place during the phase of doublecortin (DCX) expression, either as pro-proliferative effect on precursor cells or as survival-promoting effect on postmitotic cells. We here obtained quantitative data about the proliferative population and the dynamics of postmitotic dendrite development during the period of DCX expression. The question was, whether any indication could be obtained that the initiation of dendrite development is timely bound to the exit from the cell cycle. Alternatively, the temporal course of morphological maturation might be subject to additional regulatory events. RESULTS: We found that (1) 20% of the DCX population were precursor cells in cell cycle, whereas more than 70% were postmitotic, (2) the time span until newborn cells had reached the most mature stage associated with DCX expression varied between 3 days and several weeks, (3) positive or negative regulation of precursor cell proliferation did not alter the pattern and dynamics of dendrite development. Dendrite maturation was largely independent of close contacts to astrocytes. CONCLUSION: These data imply that dendrite maturation of immature neurons is initiated at varying times after cell cycle exit, is variable in duration, and is controlled independently of the regulation of precursor cell proliferation. We conclude that in addition to the major regulatory events in cell proliferation and selective survival, additional micro-regulatory events influence the course of adult hippocampal neurogenesis
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