Crowdsourcing contests: understanding the effect of competitors’ participation history on their performance

Crowdsourcing contests have become increasingly important and prevalent with the ubiquity of the Internet. Designing efficient crowdsourcing contests is not possible without the deep understanding of the factors affecting individuals’ continuous participation and their performance. Prior studies have mainly focused on identifying the effect of task-specific, environment-specific, organisation-specific, and individual-specific factors on individuals’ performance in crowdsourcing contests. And to our knowledge, there are no or very few studies on evaluating the effect of individuals’ participation history on their performance. This paper aims to address this research gap using a data set from TopCoder. This study derives competitors’ participation history factors, such as participation frequency, participation recency, winning frequency, winning recency, tenure, and last performance to construct models depicting effects of these factors on competitors’ performance in online crowdsourcing contests. The research findings demonstrate that most of competitors’ participation history factors have significant effect on their performance. This paper also indicates that competitors’ participation frequency and winning frequency moderate the relationship between last performance and performance, and relationship between tenure and performance positively. On the other hand, individuals’ participation recency and winning recency moderate relationship between last performance and performance negatively, but have no significant effect on the relationship between tenure and performance.     

The history of Plantronics半个世纪的创造与坚持

也许很多人听到缤特力（Plantronics）这个名字会感到陌生．但1969年的登月事件连教科书上都有记载。1969年7月20日。美国宇航员阿拇斯特朗登月成功．这也是人类的足迹首次路上月球．而当阿姆斯特朗从月球上传送出有那句有历史意义的名言“对一个人来说这是一小步．但对于人类来说这是一大步”时正是佩戴着缤特力的话务耳机．缤特力也有幸亲身见证这一伟大的历史时刻。     

An old game,new experience: exploring the effect of players’ personal gameplay history on game experience

This experimental study explores how game experience differs between players with different gameplay histories within the same game universe. We are interested in how prolonged engagement with a game series affects the gameplay experience in relation to the most recent game version in the series. A total of 54 participants were divided into four groups depending on their gaming experience, namely non-gamers, new-gamers, old-gamers and core-gamers. They played the mobile version of Super Mario Run, and questionnaire data was collected after the gameplay session. The results of the study showed that not only the players’ personal gameplay history but also the length of experience or degree of familiarity with the game universe affected the experience of playing a new game in the same game universe. Additionally, familiarity with the game universe had a positive impact on the feeling of competence, immersion, emotions and flow.

     

Refinement of the thermodynamic modeling of the Nb–Ni system

The Nb–Ni system is reassessed on the basis of a critical literature review involving recent experimental data. These newly published experimental data include the phase relation associated with the NbNi₈ phase, phase transition temperatures resulting from selected alloys, all invariant reaction temperatures, and enthalpies of mixing of liquid, as well as the crystallographic data on the μ$\mu$ (Nb₇Ni₆) phase. A consistent thermodynamic data set for the Nb–Ni system is obtained by optimization of the selected experimental values. The calculated phase diagram, crystallographic properties and thermodynamic properties agree reasonably with the experimental data. Noticeable improvements have been made, compared with the previous thermodynamic optimizations.     

estimates the effect of

ce and technology books to science and technology communication. The analyses show that the breeds and printing numbers of science and technology books are in good situation. They are of great variety, their printing numbers increase steadily; the contents of the books become rich and diversified.     

The mediating role of the dimensions of the perceived risk in the effect of customers’ awareness on the adoption of Internet banking in Iran

One of the major issues banks are faced with in providing Internet Banking (IB) services is the adoption of these services by the customers. This study seeks answer to the question that whether bank customers’ awareness of the services and advantages of IB is effective in reducing the negative effect of customers’ perceived risk on their intention of IB adoption. To this end, the two constructs of the dimensions of the perceived risk and IB awareness are simultaneously considered. Besides, in the research model, the effect of IB awareness on each dimension of the perceived risk and the effect of these dimensions on intention of IB adoption by the customers are investigated. The results indicate that IB awareness acts as a factor reducing all dimensions of the perceived risk (including time, financial, performance, social, security, and privacy). In addition, it was found out that except for social risk, other dimensions of the perceived risk have significantly negative effect on the intention of IB adoption. Finally, proving the direct and positive effect of IB awareness on adoption intention, it was concluded that the dimensions of customers’ perceived risk plays a mediating role in the positive effect of IB awareness on IB adoption intention. In this respect, management approaches centered on the concept of IB awareness are offered for reducing the dimensions of customers’ perceived risk.     

Concerning the knowledge domain of anticipation – awareness of early contributions in the context of defining the field

The knowledge domain of anticipation is still in the process of being defined, and is therefore subject to controversies. Science was never an endeavour of consensus but rather of debate. This additional argument to the debate integrates awareness of the early Soviet/Russian contributions to a science of anticipation. From this awareness derives the understanding of why anticipation faces opposition from established viewpoints. This article ascertains that anticipation advances a fundamental view of the living. Within this view, anticipation is always expressed in action. Short of this definitory condition, anticipation fades into the grey mass of speculative predictive methods.     

Numerical Treatment of the Loss of Hyperbolicity of?the?Two-Layer Shallow-Water System

This article is devoted to the numerical solution of the inviscid two-layer shallow water system. This system may lose the hyperbolic character when the shear between the layer is big enough. This loss of hyperbolicity is related to the appearance of shear instabilities that leads, in real flows, to intense mixing of the two layers that the model is not able to simulate. The strategy here is to add some extra friction terms, which are supposed to parameterize the loss of mechanical energy due to mixing, to get rid of this difficulty. The main goal is to introduce a technique allowing one to add locally and automatically an ??optimal?? amount of shear stress to make the flow to remain in the hyperbolicity region. To do this, first an easy criterium to check the hyperbolicity of the system for a given state is proposed and checked. Next, we introduce a predictor/corrector strategy. In the predictor stage, a numerical scheme is applied to the system without extra friction. In the second stage, a discrete semi-implicit linear friction law is applied at any cell in which the predicted states are not in the hyperbolicity region. The coefficient of this law is calculated so that the predicted states are driven to the boundary of the hyperbolicity region according to the proposed criterium. The numerical scheme to be used at the first stage has to be able to advance in time in presence of complex eigenvalues: we propose here a family of path-conservative numerical scheme having this property. Finally, some numerical tests have been performed to assess the efficiency of the proposed strategy.     

Solution of the Problem of H∞-control in the Presence of Regular Nonlinearities

For the problem with H-criterion and uncertain nonlinear block with a regular part of the perturbation vector, equations of a class of controllers were obtained. These controllers can exert a sufficiently small influence of the regular component on the given output process.     

On the Formalization of the Modal μ-Calculus in the Calculus of Inductive Constructions

We present a natural deduction proof system for the propositional modal μ-calculus and its formalization in the calculus of inductive constructions. We address several problematic issues, such as the use of higher-order abstract syntax in inductive sets in the presence of recursive constructors, and the formalization of modal (sequent-style) rules and of context sensitive grammars. The formalization can be used in the system Coq, providing an experimental computer-aided proof environment for the interactive development of error-free proofs in the modal μ-calculus. The techniques we adopt can be readily ported to other languages and proof systems featuring similar problematic issues.     

Scan of the Issue

In recent years, there have been rapid advances in sensor, sensor-on-a-chip, MEMS and wireless communication technologies. Now. massively distributed sensor networks are capable of linking people and the physical world together, providing platforms for information to be collected, shared, and processed in unprecedented ways. It is commonly recognized that sensor network research will lead to smart sentient spaces for our home and environment, work and leisure. It can help us to fight against disasters, protect us from hazards, and strengthen our defense. For the past few years, sensor networks research     

Understanding the success of strategic IT benchmarking—Exploring the role of the individual level

IT organizations use strategic IT benchmarking (SITBM) to improve business-IT alignment or for developing IT strategies. However, SITBM often does not result in the desired outcomes. Because the extant literature does not contribute to improving SITBM success, we conduct a deductive-inductive study to understand which factors distinguish successful and unsuccessful SITBM. We find that traditional project-level factors do not explain SITBM success; they are necessary but not sufficient. Rather, we show that the individual level is instrumental for explaining SITBM success, especially by ensuring the buy-in of relevant project team members – a perspective not yet discussed by pertinent literature.     

On the Uniqueness of the Solutions of some Equations of Optimal Control Theory†

The uniqueness of the solution of the differential equations derived from Pontryagin's Maximum Principle is considered for a general control problem with a freo right end of the trajectory and fixed terminal time. Under several restrictive conditions on the controlled system and performance criterion, it is proved that those equations have a unique solution. This is done by embedding the problem into a class of similar problems by means of the introduction of a positive parameter ? multiplying the performance criterion, and then making use of the uniqueness properties of an associated autonomous system together with the continuity of the solutions of the differential equations with respect to the parameter ? 

An example that illustrates the range of applicability of the theorems proved is also presented.     

Method of predicting the position of the energy center of the image of a laser beam using a parallel–hierarchical network

This paper presents a prediction method using a parallel–hierarchical (PH) network and hyperbolic smoothing of empirical data. The average prediction error is 0.55% for the developed method and 1.62% for neural networks; therefore, this method is more efficient as applied to real-time systems than traditional neural networks due to the use of the PH network and hyperbolic smoothing in implementing the operation of predicting the positions of energy centers of laser beam spot images for optical communication systems.     

On the Estimation of the Functional Size of Software from Requirements Specifications

This paper introduces a measurement procedure, called RmFFP, which describes a set of operations for modelling and estimating the size of object-oriented software systems from high-level specifications using the OO-Method Requirement Model. OO-Method is an automatic software production method. The contribution of this work is to systematically define a set of rules that allows estimating the functional size at an early stage of the software production process, in accordance with COSMIC-FFP. To do this, we describe the design, the application, and the analysis of the proposed measurement procedure following the steps of a process model for software measurement. We also report initial results on the evaluation of RmFFP in terms of its reproducibility.     

Construction of the Model of the Lambda Calculus System with Algebraic Operators

A lambda system with algebraic operators,Lambda-plus system,is introduced.After giving the definitions of the system,we present a sufficient condition for formulating a model of the system.Finally,a model of such system is constructed.     

Simulation and Improvement of the Processing Subsystem of the Manchester Dataflow Computer

The Manchester dataflow computer is a famous dynamic dataflow computer.It is centralized in architecture and simple in organization.Its overhead for communication and scheduling is very small.Its efficiency comes down,when processing elements in the processing subsystem increase.Several articles evaluated its performance and presented improved methods.The authors studied its processing subsystem and carried out the simulation.The simulation results show that the efficiency of the processing subsystem drops dramatically when average instruction execution microcycles become less and the maximum instruction execution rate is nearly attained.Two improved methods are presented to oversome the disadvantage.The improved processing subsystem with a cheap distributor made up of a bus and a two-level fixed priority circuit possesses almost full efficiency no matter whether the average nstruction execution microcycles number is large or small and even if the maximum instruction execution rate is approached.