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51.
Volkmar Pipek Volker Wulf Aditya Johri 《Computer Supported Cooperative Work (CSCW)》2012,21(2-3):261-282
We synthesize findings from longitudinal case studies examining work practices in three different organizations and propose analytical and methodological frameworks to guide the design and implementation of technologies for expertise and knowledge management. We appropriate the concept of ecosystem to argue that we can create active and useful solutions for knowledge management through a focus on interaction between two mutually intertwined elements of an ecosystem—artifacts and actors. We show that in expertise and knowledge sharing systems domain knowledge and technological knowledge are complementary and we present evidence that small solutions can have far reaching effects. Finally, we make a case for full integration of IT developers as an element of expertise sharing ecosystem. 相似文献
52.
Salvatore Grasso Johannes Poetschke Volkmar Richter Giovanni Maizza Michael J. Reece 《Journal of the American Ceramic Society》2013,96(6):1702-1705
For the first time we have demonstrated the densification of high‐purity nanostructured (davg ≈ 60 nm) tungsten carbide by High Pressure Spark Plasma Sintering (HPSPS) in the unusually low temperature range of 1200°C–1400°C. The high‐pressure sintering (i.e., 300 MPa) produced dense material at a temperature as low as 1400°C. In comparison with more conventional sintering techniques, such as SPS (80 MPa) or hot isostatic pressing, HPSPS lowered the temperature required for full densification by 400°C–500°C. High Pressure Spark Plasma Sintering, even in absence of any sintering aid or grain growth inhibitor, retained a very fine microstructure resulting in a significant improvement in both hardness (2721 HV10) and fracture toughness (7.2 MPa m1/2). 相似文献
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The "bazaar" metaphor has developed a lasting popularity in software engineering, especially as software architectures have evolved from monoliths to service orientation. Nevertheless, the metaphor is limited because it doesn't consider end users, those who develop software for themselves. Introducing such an end user, the "prosumer," to the bazaar not only suggests a changing division of work in software development but also calls for different functionality and architectural choices. The authors evaluated changing software architectures from an end-user development (EUD) perspective, taking the case of enterprise resource planning (ERP) systems as traditionally monolithically designed systems moving toward service orientation. On the basis of the study's findings, which indicated problems with the systems' technical flexibility, the authors developed a tool set for fostering EUD activities. Their new architecture for ERP systems enables end users to create their own solutions. 相似文献
55.
Joachim Gensel Rolf Meissner Volkmar Seidel 《International Journal of Circuit Theory and Applications》1973,1(4):315-322
An active RC low-pass filter using two high-gain amplifiers with bridge feedback is described which serves as terminating unit of a PCM system channel. Some conditions derived from telecommunication applications and effecting the choice of the filter structure are discussed in detail, and the principles guaranteeing imaginary zeros under the condition of absolute stability of the filter sections are explained. The measurement results confirm that, using the method described, the fairly severe requirements, particularly the high pass-band constancy demanded for units of telecommunication equipments, can be met at an economical cost. 相似文献
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Thomas Ludwig Julian Dax Volkmar Pipek Dave Randall 《Personal and Ubiquitous Computing》2016,20(4):487-515
Mobile devices have conquered nearly all parts of the daily life. These devices support their owners in specific situations, both at work and in leisure contexts, and therefore make it increasingly difficult to keep work and private life separated. Examining the practices around the use of mobile technology has become a topic of some interest as issues around “work–life balance” emerge. Although the field of HCI provides different approaches for capturing people’s activities in situ, we will show that an additional value can be obtained from a consideration of the “situated” view of contextuality, one which incorporates concerns of privacy and which identifies the reasons people might have for long-term user participation in this kind of study. Despite the undoubted sophistication of existing platforms, the issue of how to provide for dynamic adjustment to meet emerging research questions over time remains challenging. In this paper, we examine how one might approach the design of an observation environment that includes methods for understanding the way of how users reason about research, based upon the context they find themselves in. We have developed a research framework called “PartS,” which captures in situ information about the individual as well as his/her (work/personal) context and offers functionality for collaborative discussions about the information collected. Based on its evaluation, we outline six lessons that need to be considered when designing a study for capturing the subjective context and related activities from an individual user’s as well as a researcher’s perspective. 相似文献
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We introduced a reporter gene system into Pichia stipitis using the gene for the artificial green fluorescent protein (GFP), variant yEGFP. This system was used to analyse hypoxia-dependent PsADH2 regulation. Reporter gene activity was only found under oxygen limitation on a fermentable carbon source. The promoter was not induced by oxygen limitation in the Crabtree-positive yeast Saccharomyces cerevisiae. Promoter deletions revealed that a region of 15 bp contained the essential site for hypoxic induction. This motif was different from the known hypoxia response elements of S. cerevisiae but showed some similarity to the mammalian HIF-1 binding site. Electrophoretic mobility shift assays demonstrated specific protein binding to this region under oxygen limitation. Similar to the S. cerevisiae heme sensor system, the promoter was induced by Co(2+). Cyanide was not able to mimic the effect of oxygen limitation. The activation mechanism of PsADH2 also, in this respect, has similarities to the mammalian HIF-1 system, which is inducible by Co(2+) but not by cyanide. Thus, the very first promoter analysis in P. stipitis revealed a hitherto unknown mechanism of oxygen sensing in yeast. 相似文献
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Barley tempeh was produced by fermenting barley kernels with Rhizopus oligosporus. The potential of the yeasts Saccharomyces cerevisiae (three strains), S. boulardii (one strain), Pichia anomala (one strain) and Kluyveromyces lactis (one strain) to grow together with R. oligosporus during barley tempeh fermentation was evaluated. All yeast strains grew during the fermentation and even during cold storage of tempeh (P<0.01). The growth of yeasts slightly increased the ergosterol contents, but did not influence amino acid contents and compositions, and did not reduce phytate contents. Slight increases of vitamins B(6) and niacinamide, and slight decreases of B(1) and biotin were observed. Quantification of fungal growth is difficult during mixed species fermentations because ergosterol is found in all fungal species, and colony-forming-unit (cfu) estimations are not reliable for R. oligosporus and other sporulating fungi. Therefore, we developed a quantitative real-time PCR method for individually quantifying S. cerevisiae and R. oligosporus growth in barley tempeh. The PCR results were highly correlated with the ergosterol content of R. oligosporus and with the number of cfu of S. cerevisiae. Thus, real-time PCR is a rapid and selective method to quantify yeasts and R. oligosporus during mixed species fermentation of inhomogenous substrate such as barley tempeh. 相似文献