Scientific research as an occupation in eighteenth-century Paris     

Roger Hahn 《Minerva》1975,13(4):501-513

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More than Bags of Words: Sentiment Analysis with Word Embeddings     

Elena Rudkowsky  Martin Haselmayer  Matthias Wastian  Marcelo Jenny  Štefan Emrich  Michael Sedlmair 《Communication methods and measures》2018,12(2-3):140-157

ABSTRACT

Moving beyond the dominant bag-of-words approach to sentiment analysis we introduce an alternative procedure based on distributed word embeddings. The strength of word embeddings is the ability to capture similarities in word meaning. We use word embeddings as part of a supervised machine learning procedure which estimates levels of negativity in parliamentary speeches. The procedure’s accuracy is evaluated with crowdcoded training sentences; its external validity through a study of patterns of negativity in Austrian parliamentary speeches. The results show the potential of the word embeddings approach for sentiment analysis in the social sciences.  相似文献   

University physics students’ ideas of thermal radiation expressed in open laboratory activities using infrared cameras     

Jesper Haglund  Emil Melander  Matthias Weiszflog  Staffan Andersson 《Research in Science & Technological Education》2017,35(3):349-367

Background: University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation and a heat pump. Students had access to handheld infrared (IR) cameras for their investigations.

Purpose: The purpose of the research was to explore students’ interactions with reformed thermodynamics laboratory activities. It was guided by the research question: How do university physics students make use of IR cameras in open-ended investigation of thermal radiation as a phenomenon?

Sample: The study was conducted with a class of first-year university physics students in Sweden. The interaction with the activities of four of the students was selected for analysis. The four students are males.

Design and methods: We used a qualitative, interpretive approach to the study of students’ interaction. The primary means of data collection was video recording of students’ work with the laboratory activities and their subsequent presentations. The analysis focused on how IR cameras helped students notice phenomena relating to thermal radiation, with comparison to previous research on students’ conceptions of thermal radiation.

Results: When using the IR camera, students attended to the reflection of thermal radiation on shiny surfaces, such as polished metals, windows or a whiteboard and emissive properties of surfaces of different types. In this way, they went beyond using the technology as a temperature probe. Students were able to discuss merits and shortcomings of IR cameras in comparison with digital thermometers.

Conclusions: With the help of IR cameras, university physics students attend to thermal phenomena that would otherwise easily go unnoticed.  相似文献   

Sociotechnical constituencies, game theory, and the diffusion of compact discs. An inter-disciplinary investigation into the market for recorded music     

Matthias Klaes 《Research Policy》1997,25(8):1221-1234

This article was motivated by the inquiry of the National Heritage Committee of the British House of Commons into the price of compact discs in 1993. Its general thrust is to foster the dialogue between sociological approaches to the study of innovation and microeconomic theory. To do this, it presents a comprehensive case study of technological innovation in the market for recorded music in Britain. The material is analysed with the aid of the ‘sociotechnical constituencies’ approach recently proposed in this journal by Alfonso Molina, followed by a game theoretical analysis of competitive alignment between the dominant constituents. Using this interdisciplinary approach, the article argues that technological innovation may induce price rigidities by allowing the establishment of focal points for tacit collusion. The innovation of compact discs enabled the major record companies to redefine the overall price level to their advantage, after the industry had undergone a period of profit-squeezing price-competition. This has the important policy implication that radical product innovation may call for regulative changes in the techno-institutional structure of the market.  相似文献   

Fetal heart rate and variability: stability and prediction to developmental outcomes in early childhood     

DiPietro JA  Bornstein MH  Hahn CS  Costigan K  Achy-Brou A 《Child development》2007,78(6):1788-1798

Stability in cardiac indicators before birth and their utility in predicting variation in postnatal development were examined. Fetal heart rate and variability were measured longitudinally from 20 through 38 weeks gestation (n = 137) and again at age 2 (n = 79). Significant within-individual stability during the prenatal period and into childhood was demonstrated. Fetal heart rate variability at or after 28 weeks gestation and steeper developmental trajectories were significantly associated with mental and psychomotor development at 2 years (n = 82) and language ability at 2.5 years (n = 61). These data suggest that the foundations of individual differences in autonomic control originate during gestation and the developmental momentum of the fetal period continues after birth.  相似文献   

Efficient reverse k-nearest neighbor estimation     

Elke Achtert  Christian B?hm  Peer Kr?ger  Peter Kunath  Alexey Pryakhin  Matthias Renz 《Informatik - Forschung und Entwicklung》2007,15(3):179-195

The reverse k-nearest neighbor (RkNN) problem, i.e. finding all objects in a data set the k-nearest neighbors of which include a specified query object, has received increasing attention recently. Many industrial and scientific applications call for solutions of the RkNN problem in arbitrary metric spaces where the data objects are not Euclidean and only a metric distance function is given for specifying object similarity. Usually, these applications need a solution for the generalized problem where the value of k is not known in advance and may change from query to query. In addition, many applications require a fast approximate answer of RkNN-queries. For these scenarios, it is important to generate a fast answer with high recall. In this paper, we propose the first approach for efficient approximative RkNN search in arbitrary metric spaces where the value of k is specified at query time. Our approach uses the advantages of existing metric index structures but proposes to use an approximation of the nearest-neighbor-distances in order to prune the search space. We show that our method scales significantly better than existing non-approximative approaches while producing an approximation of the true query result with a high recall.  相似文献   

The Online Market for Illegal Copies of Magazines: A German Case Study     

Marcel Garz  Armin Rott  Matthias Wass von Czege 《广播与电子媒介杂志》2015,59(1):169-183

A few years ago, publishing companies started to sell digital copies of their magazines. This study investigates a consequence of this change: the increasing online trade with illegal copies. We collected data on almost 10,000 issues of German magazines that are illegally offered online. The files are distributed in a three-sided market, in which a small number of platforms bring suppliers of illegal copies, consumers, and advertisers together. The market has been growing rapidly—between 2009 and 2012 by a factor of 10. In contrast to the legal magazine market, the illegal trade mostly concerns IT and consumer electronics magazines.  相似文献   

Droplet formation and shrinking in aqueous two-phase systems using a membrane emulsification method     

Hans Breisig  Matthias Wessling 《Biomicrofluidics》2015,9(4)

Using a membrane emulsification method based on porous hollow-fiber membranes in combination with an aqueous two-phase system (ATPS), we are able to produce “water-in-water” droplets with narrow-dispersed size distributions. The equilibrium phases of the aqueous two-phase system polyethylene glycol-dipotassium hydrogen phosphate are used for this purpose. The droplet diameter of a given fluid system is determined by the flow rates of the continuous and disperse phase as well as the hollow fiber dimensions. When diluting the disperse phase and thus moving the ATPS system out of equilibrium, the droplet size can be further reduced in comparison to the equilibrium case. Generally, droplets formed with this method have diameters 20%–60% larger than the inner hollow fiber diameter. The new strategy of diluting the disperse phase allows the production of droplet diameter below the inner diameter of the membrane.  相似文献   

Problematic transitions from school to employment: freeters and NEETs in Japan and Germany     

Matthias Pilz  Kirsten Schmidt-Altmann  Mikiko Eswein 《Compare》2015,45(1):70-93

In the international debate surrounding transitions from school to employment, Japan and Germany are regularly cited as examples of success. This article draws on the Japanese concepts represented by two problematic groups – freeters and NEETs – to demonstrate that over recent years, young people in both countries have also been facing serious problems with the transition process. Interpretation of empirical data also, however, reveals a number of contrasts between them. We focus here on differences in their educational systems and on the role each system plays within its own society. The article also uses divergent recruitment practices and employment structures as vehicles for comparison and interpretation.  相似文献   

Learning to solve ill-defined statistics problems: does self-explanation quality mediate the worked example effect?     

Bichler  Sarah  Stadler  Matthias  Bühner  Markus  Greiff  Samuel  Fischer  Frank 《Instructional Science》2022,50(3):335-359

Instructional Science - Extensive research has established that successful learning from an example is conditional on an important learning activity: self-explanation. Moreover, a model for...  相似文献