Menu search: random or systematic?

This paper questions the conclusion that menu search is random, not systematic. Three sources of evidence—search times per target as a function of target position, eye movement patterns during search, and the cumulative probability of locating a target as a function of time—cited in support of random search (Card, 1982, 1983) are re-examined and shown to be consistent with systematic, sequential search.     

Uncertainty in crop model predictions: What is the role of users?

Crop models are used to estimate crop productivity under future climate projections, and modellers manage uncertainty by considering different scenarios and GCMs, using a range of crop simulators. Five crop models and 20 users were arranged in a randomized block design with four replicates. Parameters for maize (well studied by modellers) and rapeseed (almost ignored) were calibrated. While all models were accurate for maize (RRMSE from 16.5% to 25.9%), they were, to some extent, unsuitable for rapeseed. Although differences between biomass simulated by the models were generally significant for rapeseed, they were significant only in 30% of the cases for maize. This could suggest that in case of models well suited to a crop, user subjectivity (which explained 14% of total variance in maize outputs) can hide differences in model algorithms and, consequently, the uncertainty due to parameterization should be better investigated.     

Practical CTL* model checking: Should SPIN be extended?

We describe an efficient CTL^* model checking algorithm based on alternating automata and games. A CTL^* formula, expressing a correctness property, is first translated to a hesitant alternating automaton and then composed with a Kripke structure representing the model to be checked, after which this resulting automaton is then checked for nonemptiness. We introduce the nonemptiness game that checks the nonemptiness of a hesitant alternating automaton (HAA). In the same way that alternating automata generalise nondeterministic automata, we show that this game for checking the nonemptiness of HAA, generalises the nested depth-first algorithm used to check the nonemptiness of nondeterministic Büchi automata (used in Spin).     

Windows Me:to me?you or him?别无选择?

引子： 9月 14日,微软公司新的消费型 Windows版本—— Windows Me,即 Windows Millennium Edition在美国零售市场上面世了。作为 Windows 95、 Windows 98、 Windows 98第二版 (SE)之后的最新版本,距 1999年 6月 10日发布 Windows 98 SE仅时隔一年。对于这样一款产品,业界业外众说纷纭,有人说： Windows Me发出了 Windows 98死亡的咒语;也有人怀疑： Windows Me是否真的作出了重大的改进和升级;还有人惊呼： Windows Me排斥第三代应用程序。虽然 Windows Me还没有在中国上市,虽然此“ me”也非彼“ me”,但在不久的将来,他将对作为微软公司的 me、作为消费者的 you和作为第三方软件开发商以及 PC厂商的 him带来又一次重大的影响。     

Studying Organizational Creativity as Process: Fluidity or Duality?

This paper contributes to process studies on organizational creativity by developing two competing research agendas. The first perspective, the ‘becoming’ view, depicts creativity as a constant flow of activity that crystallizes every once in a while in unpredictable moments of creativity. The second perspective, the ‘practice’ view, understands creativity as a practised social process, in which structures play the important role of both enabling and constraining individual agents in pursuing creativity as a collective phenomenon. We compare and contrast these two theoretical perspectives, which are based on different process ontologies, and discuss their methodological implications. We argue that the practice perspective offers particular promise, because it allows us to address the important yet paradoxical question of how creativity may be organized and managed.     

How Should the Chinese Government Invest R&D Funds: Enterprises or Institutions?

With the rapid increase of the government R&D investment in China, the efficient optimization of the R&D investment areas of the Chinese government significantly influences regional innovation productivity and economic growth in the long run. By expanding the R&D-based growth model and using empirical analysis, this paper discusses the optimal combination for the government to coordinate its R&D expenditure as productive public investment in various sectors, under the condition of promoting long-term economic growth, is discussed by considering the aspects of capability for independent innovation, the development capability for basic knowledge, and the absorption capability for the technique. Results are as follows. (1) The level of production efficiency of enterprises, such as the capability for independent innovation, the development capability for basic knowledge, and absorption capability, influences the inclination of the government to invest in enterprises and institutions. When an enterprise has a high production efficiency level, technological level A, and knowledge storage B, increased investment from institutions to the enterprise can significantly promote regional economy growth. Otherwise, the government should increase R&D investment in institutions. (2) The government R&D investment in institutions can indirectly promote economic growth through the promotion of human capital and the understanding and absorption capacity of external knowledge, independent innovation capability, and basic knowledge development capability of enterprises. This paper may help the government to create appropriate policies with higher efficiency in R&D investment, and promote technical progress and economic growth in China.     

‘Requirements-Uncertainty’: Is it best formulated as a latent,aggregate or profile construct?

This paper identifies the strategies that experienced information systems (IS) project managers say they use to cope with requirements-uncertainty (RU) when managing development projects for external clients. It is shown that project managers (PMs) claim to use different strategies for coping with the different dimensions of requirements-uncertainty, as this notion has been formulated in IS literature. Based on this finding, it is proposed that perhaps requirements-uncertainty should be formulated as a profile construct, and not as a latent or aggregate construct, if it is to have pragmatic validity as a guide to action for project managers.     

Optimizing counter-terror operations: Should one fight fire with “fire” or “water”?

This paper deals dynamically with the question of how recruitment to terror organizations is influenced by counter-terror operations. This is done within an optimal control model, where the key state is the (relative) number of terrorists and the key controls are two types of counter-terror tactics, one (“water”) that does not and one (“fire”) that does provoke recruitment of new terrorists. The model is nonlinear and does not admit analytical solutions, but an efficient numerical implementation of Pontryagin's minimum principle allows for solution with base case parameters and considerable sensitivity analysis. Generally, this model yields two different steady states, one where the terror organization is nearly eradicated and one with a high number of terrorists. Whereas water strategies are used at almost any time, it can be optimal not to use fire strategies if the number of terrorists is below a certain threshold.     

Decline in accuracy of automatic speech recognition as a function of time on task: fatigue or voice drift?

Recognition accuracy of speech recognition devices tends to decline during an extended period of continuous use. Although this deterioration in performance is commonly acknowledged, there has been little systematic observation of the phenomenon, and no clear account of its causes is available. The aim of the present study was to provide some indication of the magnitude and time course of this decline in performance, and to clarify the nature of underlying changes in speech behaviour. There experiments are described. Experiment 1 confirmed that there is a fall-off in recognition accuracy during a half-hour session of a data entry task, and that this occurs for both naive and practised subjects. In Experiment 2, no recovery was observed in recognition performance when short rest breaks were scheduled, indicating that vocal fatigue was not a major factor. The effects of template retraining in mid-session were investigated in Experiment 3. This procedure was found to be effective in restoring recognition accuracy, and the retrained templates were relatively robust. The implications of these findings for operational use of speech recognition devices are briefly discussed. For most applications, one-off template retraining is seen as a more appropriate solution to the problem of voice drift than more complex solutions based on adaptive templates.     

Demand characteristics in assessing motion sickness in a virtual environment: or does taking a motion sickness questionnaire make you sick?

The experience of motion sickness in a virtual environment may be measured through pre and postexperiment self-reported questionnaires such as the Simulator Sickness Questionnaire (SSQ). Although research provides converging evidence that users of virtual environments can experience motion sickness, there have been no controlled studies to determine to what extent the user's subjective response is a demand characteristic resulting from pre and posttest measures. In this study, subjects were given either SSQ's both pre and postvirtual environment immersion, or only postimmersion. This technique tested for contrast effects due to demand characteristics in which administration of the questionnaire itself suggested to the participant that the virtual environment may produce motion sickness. Results indicate that reports of motion sickness after immersion in a virtual environment are much greater when both pre and postquestionnaires are given than when only a posttest questionnaire is used. The implications for assessments of motion sickness in virtual environments are discussed.