The Effect of Social Factors on User-Generated Content Productivity: Evidence from Flickr.com

User-generated content (UGC) is a valuable information resource on social media. However, we currently know little about why people are constantly producing digital content. In an effort to gather more contents, many UGC service providers are trying to help users improve their social experience. Through the lens of social network theories, our study illustrates that social influence and social interaction between users will motivate users to contribute contents on UGC platforms. We hence design an empirical study to discover the social factors influencing users’ productivity. By collecting data from Flickr.com, we expect to support that individuals’ perception of “social comparison” and “social identity” will positively influence users’ behavior of content generation. We also assume that social interaction, in terms of tie strength, will increase users’ productivity of content

A Comparative Evaluation of Materials Selection in the Integrated Course of NHCE and NPCE

Based on the theories of textbook evaluation, this research chooses materials from the first and second volumes of the Student’s Books in New Progressive College English Integrated Course (short for NPCE, published by Shanghai Foreign Language Education Press in 2017) and New Horizon College English Reading and Writing Course (short for NHCE, published by Foreign Language Teaching and Research Press in 2015) as research subjects for comparison and analysis. The paper analyses the two sets of books in terms of language, contents and exercises according to the College English Course Requirements, and tries to find out which one can better cater for the needs of students. The comparative analyses mainly includes word quantity, word difficulty, word frequency, the proportion of new words, the total number of sentences and their complexity, the genres and topics of the texts and the comprehensiveness of exercises. Results indicate that NHCE is more suitable for students in terms of language and picks passages which have different emphases from NPCE and focuses more on arousing students’ thinking, while the topics and exercises in NPCE are more comprehensive. Both sets of books have their advantages and disadvantages. It is expected that this research will provide textbook compilers with help and reference in their future work.

A Critical Examination of BonJour’s, Haack’s, and Dancy’s Theory of Empirical Justification

In this paper, we shall describe and critically evaluate four contemporary theories which attempt to solve the problem of the infinite regress of reasons: BonJour's ‘impure’ coherentism, BonJour's foundationalism, Haack's ‘foundherentism’ and Dancy's pure coherentism. These theories are initially put forward as theories about the justification of our empirical beliefs; however, in fact they also attempt to provide a successful response to the question of their own ‘metajustification.’ Yet, it will be argued that 1) none of the examined theories is successful as a theory of justification of our empirical beliefs, and that 2) they also fall short of being adequate theories of metajustification. It will be further suggested that the failure of these views on justification is not coincidental, but is actually a consequence of deeper and tacitly held problematic epistemological assumptions (namely, the requirements of justificatory generality and epistemic priority), whose acceptance paves the way towards a generalized scepticism about empirical justification

Finite Temperature Models of Bose-Einstein Condensation

The theoretical description of trapped weakly-interacting Bose-Einstein condensates is characterized by a large number of seemingly very different approaches which have been developed over the course of time by researchers with very distinct backgrounds. Newcomers to this field, experimentalists and young researchers all face a considerable challenge in navigating through the `maze' of abundant theoretical models, and simple correspondences between existing approaches are not always very transparent. This Tutorial provides a generic introduction to such theories, in an attempt to single out common features and deficiencies of certain `classes of approaches' identified by their physical content, rather than their particular mathematical implementation. This Tutorial is structured in a manner accessible to a non-specialist with a good working knowledge of quantum mechanics. Although some familiarity with concepts of quantum field theory would be an advantage, key notions such as the occupation number representation of second quantization are nonetheless briefly reviewed. Following a general introduction, the complexity of models is gradually built up, starting from the basic zero-temperature formalism of the Gross-Pitaevskii equation. This structure enables readers to probe different levels of theoretical developments (mean-field, number-conserving and stochastic) according to their particular needs. In addition to its `training element', we hope that this Tutorial will prove useful to active researchers in this field, both in terms of the correspondences made between different theoretical models, and as a source of reference for existing and developing finite-temperature theoretical models.Comment: Detailed Review Article on finite temperature theoretical techniques for studying weakly-interacting atomic Bose-Einstein condensates written at an elementary level suitable for non-experts in this area (e.g. starting PhD students). Now includes table of content

Integrated Educational Project of Theoretical, Experimental, and Computational Analyses

This research demonstrates how to design an integrated capstone project by including theoretical, experimental and computational analyses of a truss bridge. The project mainly focused on leading students to approach engineering problems with various methods and to understand the advantages and disadvantages of each method. The students applied three methods to acquire the values of stresses and deflections of members in the given truss bridge. First, they calculated the stresses and deformations theoretically. Second, they actually conducted an experiment of the truss bridge with electronic measuring equipment. Lastly, they built two simulation models with Autodesk Inventor and Dassault Systèmes SolidWorks. From the comparisons of above three methods, students were guided to the validation of assumptions of theories.Cockrell School of Engineerin

Ecological-evolutionary feedback in evolved lineages of Pseudomonas fluorescens : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Environmental Microbiology at Massey University, Albany, New Zealand

Multicellularity cannot proceed to subsequent stages without the evolution of collectives. Thus, it becomes essential to understand the evolution of cooperation before the evolution of multicellularity. However, understanding the evolution of cooperation presents a problem. This is because natural selection rewards selfish behavior; yet, in nature, cooperation is apparently common. Here arises a conflict between individual and collective interest and thus raises questions concerning the evolution of cooperative behavior. Assortment between cooperating types has been identified as the underlying mechanism behind theories for the evolution of cooperation. However, these theories assume the environment to be stable and fail to acknowledge interactions are density and frequency dependent (two components of the environment), capable of generating co-evolutionary interactions. In this regard the feedback between ecology and evolution (eco-evo feedback) is of likely importance. In a previous experiment, a rudimentary life cycle was established in model bacterial populations where lineages were repeatedly cycled between a cellulose producing, group living cooperator type, termed WS, and solitary, free living cheater types, termed SM. The results of the experiment showed that collective level fitness increased in evolved lineages compared to baseline lineages. I believe that the eco-evo feedback is likely to have occurred on the WS-SM interactions and that this is responsible for the increased fitness of the evolved lineages. The aim of this thesis was to identify the presence of the feedback in evolved lineages. I compared the evolutionary dynamics of frequency dependent interactions between WS and SM, and population dynamics due to density dependent factors on the interactions between WS and SM. I also report the joint influence of evolutionary and population dynamic patterns via ecospace diagrams of the ancestor and evolved lineages. The results showed that the interactions between WS and SM are both frequency and density dependent and the joint influence of the above two factors reveals the presence of an eco-evo feedback. The nature of the feedback is suggested to be a reduced transition capacity of SM to switch to WS in evolved lineages. The tendency of evolved SM to produce few WS suggest a strategy on the part of the SM to save the metabolic cost of production of cellulose, by WS, and to trade-off this cost with an increase in fitness of the evolved lineages

Quasi Indexicals

I argue that not all context dependent expressions are alike. Pure (or ordinary) indexicals behave more or less as Kaplan thought. But quasi indexicals behave in some ways like indexicals and in other ways not like indexicals. A quasi indexical sentence φ allows for cases in which one party utters φ and the other its negation, and neither party’s claim has to be false. In this sense, quasi indexicals are like pure indexicals (think: “I am a doctor”/“I am not a doctor” as uttered by different individuals). In such cases involving a pure indexical sentence, it is not appropriate for the two parties to reject each other’s claims by saying, “No.” However, in such cases involving a quasi indexical sentence, it is appropriate for the par- ties to reject each other’s claims. In this sense, quasi indexicals are not like pure indexicals. Drawing on experimental evidence, I argue that gradable adjectives like “rich” are quasi indexicals in this sense. e existence of quasi indexicals raises trouble for many existing theories of context dependence, including standard contextualist and relativist theories. I propose an alternative semantic and pragmatic theory of quasi indexicals, negotiated contextualism, that combines insights from Kaplan 1989 and Lewis 1979. On my theory, rejection is licensed with quasi indexicals (even when neither of the claims involved has to be false) because the two utterances involve conflicting proposals about how to update the conversational score. I also adduce evidence that conflicting truth value assessments of a single quasi indexical utterance exhibit the same behavior. I argue that negotiated contextualism can account for this puzzling property of quasi indexicals as well

A distributed framework for semi-automatically developing architectures of brain and mind

Developing comprehensive theories of low-level neuronal brain processes and high-level cognitive behaviours, as well as integrating them, is an ambitious challenge that requires new conceptual, computational, and empirical tools. Given the complexities of these theories, they will almost certainly be expressed as computational systems. Here, we propose to use recent developments in grid technology to develop a system of evolutionary scientific discovery, which will (a) enable empirical researchers to make their data widely available for use in developing and testing theories, and (b) enable theorists to semi-automatically develop computational theories. We illustrate these ideas with a case study taken from the domain of categorisation