Bridging learning theory and dynamic epistemic logic

This paper discusses the possibility of modelling inductive inference (Gold 1967) in dynamic epistemic logic (see e.g. van Ditmarsch et al. 2007). The general purpose is to propose a semantic basis for designing a modal logic for learning in the limit. First, we analyze a variety of epistemological notions involved in identification in the limit and match it with traditional epistemic and doxastic logic approaches. Then, we provide a comparison of learning by erasing (Lange et al. 1996) and iterated epistemic update (Baltag and Moss 2004) as analyzed in dynamic epistemic logic. We show that finite identification can be modelled in dynamic epistemic logic, and that the elimination process of learning by erasing can be seen as iterated belief-revision modelled in dynamic doxastic logic. Finally, we propose viewing hypothesis spaces as temporal frames and discuss possible advantages of that perspective.     

5～9岁儿童极限概念认知发展的实验研究

皮亚杰(1985)认为儿童非要到11或12岁时才能掌握极限的概念。这个观点十分让人感兴趣,然而在众多文献中却很难发现相关研究。本研究运用实验法研究了5、6、7、9四组儿童的极限概念。结果表明:儿童在极限概念的发展存在两个快速期,即5~6岁和6~7岁;5岁儿童处于极限概念萌芽状态,6岁儿童有了部分极限概念,7岁儿童极限概念有了进一步发展但不稳定;9岁儿童开始接近有了极限概念,但仍未到达完全理解。本研究结果支持了皮亚杰的相关观点。     

Framing of imprecise quantities: When are lower interval bounds preferred to upper bounds?

Imprecisely known quantities (e.g., predictions) are often described in approximate terms as “more than X” or “less than Y” (e.g., “Ann will earn more than $50 000” or “less than $60 000”). Such phrases carry both quantitative and qualitative (pragmatic) information. Three studies are reported showing that lower limit estimates (more than, over, minimum) are generally more frequent, and considered more appropriate than upper limit estimates (less than, under, maximum) over a wide range of contexts. This is partly due to scalar properties of the number system, where lower numbers are attained before, and included in higher numbers, but not vice versa. As a result, upper limit statements are perceived as negations, and carry more specific information about the speaker's communicative concerns. Upper limit statements are preferred with amounts or quantities that can be perceived as small, whereas lower limit statements can be used both to indicate large quantities and as a default. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of position of speed limit signs and the presence of speed camera on Malaysian drivers’ speed choice: An eye-tracking study

Speeding is one of the most common driving violations in the world including in Malaysia. Reducing speed-related fatalities is one of Malaysia’s strategies to improve road safety. The current study aimed to investigate the effect of speed limit sign positioning and the presence of speed camera on drivers’ judgments about the appropriate speed to drive and their associated eye movements. Twenty participants took part in the study, and thirty two images of roads with a range of actual speed limits were presented. In each picture the displayed speed limit was edited to 30% lower than what participants think is appropriate on average. Speed limit signs were either presented on the road or on the speed limit sign boards at the road sides, and a speed camera sign was either present or not. Drivers judged a lower appropriate speed to drive when the camera sign was present than absent, while there was a wider spread of differences between judged and displayed speed when the speed limit sign was presented on the board than on the road. Drivers were quicker in fixating and looked more at the general area in which the speed limit sign appeared. Therefore drivers’ visual attention across scenes may be manipulated by the sign positions. These low-cost interventions could be useful in managing speed choice in Malaysia.     

The effect of visual HMIs of a system assisting manual drivers in manoeuvre coordination in system limit and system failure situations

Ambiguous situations in traffic often require communication and cooperation between road users. In order to resolve these situations and increase cooperative driving behavior in situations of merging or turning left, manual drivers could be assisted by an advanced driver assistance system (ADAS) for cooperative driving. This simulator study investigated the behavior of drivers confronted with system limits and failures of such a system. The ADAS used in this study informed the driver about an upcoming cooperation situation and gave advice on how to behave (e.g. reduce speed, change lane). Two test situations were implemented: a system freeze and an unexpected event, which could not be detected by the system. In order to find the most fitting HMI solution, the place of presentation (head-up display (HUD) vs. instrument cluster) as well as the form of presentation (dynamic vs. symbolic) were varied. The results indicated that the most fitting HMI solution to support the driver in a complex coordinated driving situation is a dynamic HUD, mainly due to the positive effect on glance behavior. However, advantages of both forms of presentation were revealed, as each form of presentation increased the probability of recognition for one of the test situations. The fewest collisions took place with the dynamic form of presentation.     

How fast would you (or should you) drive here? Investigation of relationships between official speed limit,perceived speed limit,and preferred speed

Speed is a critical risk factor, which makes its management the central point of the Vision Zero approach. Driving speed is influenced by speed choice, and in turn by the perception of the road parameters, as well as by the characteristics of drivers. Credible speed limits and self-explaining roads have been suggested as promising countermeasures; however, these rather theoretical concepts have only rarely been operationalized and quantified.The aim of this study was to investigate the relationships between speed indicators (official speed limit, perceived speed limit, preferred speed), as well as their differences, and to determine which road and personality characteristics influence them. Compared to previous studies, we introduced several innovative features, including a richer personality dataset based on three different questionnaires, a focus on all three types of roads (urban, rural, transition), and representative data on observed speeds.Using statistical models of the speed indicators, we found that both speed limit belief and speed choice, as well as their differences, are often influenced by the same characteristics. These are mainly more generous road design (higher road class, higher speed limit, and wider road) and the presence of additional elements (vegetation, pavements, and pedestrian crossings). These characteristics may help improve the credibility of speed limits and self-explaining performance.     

Analysis of drivers’ behavior under reduced visibility conditions using a Structural Equation Modeling approach

One way to improve safety under reduced visibility conditions (i.e., reduce the chances of visibility related crashes) is to improve drivers’ behavior under such adverse weather conditions. The aim of this paper is to thoroughly examine drivers’ responses under low visibility conditions and quantify the impacts and values of various factors found to be related to drivers’ compliance and drivers’ satisfaction with variable speed limit (VSL) and changeable message signs (CMS) instructions in different visibility, traffic conditions, and on two types of roadways; freeways and two-lane roads.The data used for the analyses were obtained from a self-reported questionnaire survey carried out among 566 drivers in Central Florida, USA. To achieve these goals, Explanatory Factor Analysis (EFA) and Structural Equation Modeling (SEM) approaches were adopted.The results revealed that drivers’ satisfaction with VSL/CMS was the most significant factor that positively affected drivers’ compliance with advice or warning messages displayed on VSL/CMS under different fog conditions followed by human factors. Moreover, it was found that roadway type affected drivers’ compliance to VSL instructions under medium and heavy fog conditions. Furthermore, drivers’ familiarity with VSL and human factors were the significant factors affecting drivers’ satisfaction with VSL/CMS advice under reduced visibility conditions. Based on the findings of the present study, several recommendations are suggested as guidelines to improve drivers’ behavior in such reduced visibility conditions by enhancing drivers’ compliance with VSL/CMS instructions.     

Ontologies and Worlds in Category Theory: Implications for Neural Systems

We propose category theory, the mathematical theory of structure, as a vehicle for defining ontologies in an unambiguous language with analytical and constructive features. Specifically, we apply categorical logic and model theory, based upon viewing an ontology as a sub-category of a category of theories expressed in a formal logic. In addition to providing mathematical rigor, this approach has several advantages. It allows the incremental analysis of ontologies by basing them in an interconnected hierarchy of theories, with an operation on the hierarchy that expresses the formation of complex theories from simple theories that express first principles. Another operation forms abstractions expressing the shared concepts in an array of theories. The use of categorical model theory makes possible the incremental analysis of possible worlds, or instances, for the theories, and the mapping of instances of a theory to instances of its more abstract parts. We describe the theoretical approach by applying it to the semantics of neural networks.     

医学专业面临的危机：利益冲突——再论医学专业精神

医患间未能遵守利益限度和利益边界原则,使矛盾转化为冲突。当前我国面临的医患冲突与一些国家相比是全面而深刻的。体制与非体制原因相互交错,直接冲突与间接冲突相互影响,理性冲突向非理性冲突转化,群体性与个体性的不同表现,即发生与后发性的不同特点,是我国医患冲突演化的规律与特征。要正确对待第三方的介入。端正专业思想是理顺医患关系的治本之道。     

How to Make Naturalism Safe for Supernaturalism: An Evaluation of Willem Drees's Supernaturalistic Naturalism

Naturalism is often considered to be antithetical to theology and genuine religion. However, in a series of recent books and articles, Willem Drees has proposed a scientifically informed naturalistic account of religion, which, he contends, is not only compatible with supernaturalistic religion and theology but provides a better account of both than either purely naturalistic or purely supernaturalistic accounts. While rejecting both epistemological and methodological naturalism, Drees maintains that ontological naturalism offers the best philosophical account of the natural world and that, in addition, it provides the opening for a supernaturalistic understanding of religion and theology, one that best fits the condition of epistemic and moral distance from the transcendent characteristic of religious wonderers and wanderers. In this paper I examine Drees's claim and argue that it is seriously flawed. I show that Drees's naturalism is, in fact, both methodologically and epistemologically naturalistic. I also show that his attempts to limit naturalism to the sphere of the natural world by means of the phenomena of limit questions and underdetermination fail. Arguing for a more optimistic, but also, I contend, more empirically accurate account of human epistemic and moral capacities, I propose a full-fledged scientifically based naturalistic account of theology.