2,447 research outputs found

    Time-Staging Enhancement of Hybrid System Falsification

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    Optimization-based falsification employs stochastic optimization algorithms to search for error input of hybrid systems. In this paper we introduce a simple idea to enhance falsification, namely time staging, that allows the time-causal structure of time-dependent signals to be exploited by the optimizers. Time staging consists of running a falsification solver multiple times, from one interval to another, incrementally constructing an input signal candidate. Our experiments show that time staging can dramatically increase performance in some realistic examples. We also present theoretical results that suggest the kinds of models and specifications for which time staging is likely to be effective

    The impact of educational technology: A radical reappraisal of research methods

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    How can we decide whether some new tool or approach is valuable? Do published results of empirical research help? This paper challenges strongly entrenched beliefs and practices in educational research and evaluation. It urges practitioners and researchers to question both results and underlying paradigms. Much published research about education and the impact of technology is pseudoā€scientific; it draws unwarranted conclusions based on conceptual blunders, inadequate design, soā€called measuring instruments that do not measure, and/or use of inappropriate statistical tests. An unacceptably high portion of empirical papers makes at least two of these errors, thus invalidating the reported conclusions

    Is African science true science? Reflections on the methods of African science

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    The general character of science and the methodology it employs are in specific terms referred to as observation and experimentation. These two methodologies reflect how science differs from other systematic modes of inquiries. ThisĀ  description characterises, strictly, ā€˜Western scienceā€™ and it is contrasted with the indigenous mode of enquiry that has come under the name, ā€˜African scienceā€™. In contemporary scholarship, ā€˜African scienceā€™ is being condemned to the level of the mysticoreligious or supernaturalist worldview. ā€˜African scienceā€™ is said to be purely esoteric, personal, and devoid of elements of objectivity and rigorous theorization. In this paper, I re-examine this recondite issue by further reflecting andĀ  strengthening some of the ideas put forward by some African scholars to affirm that there is a distinct method of ā€˜African scienceā€™ that can be termed scientific. In defending a pluralist thesis toward knowledge, scientific inclusive, this paper posits that there exist varieties of inquiry beyond what has been developed in the ā€˜Westā€™ which can still be justifiably termed scientific. In addition to pluralism, it arguesĀ  further that the social character of science, which makes it a part of social and cultural traditions, qualifiedly justifies ā€˜African scienceā€™ as a true science. I will employ the newly formulated conversational method endorsed by the Conversational School of Philosophy (CSP) in this inquiry.Keywords: African science, mystico-religious, rigorous, pluralism, Western scienc

    AN EXPERIMENTAL STUDY IN OVERCOMING HYPOTHESIS-CONFIRMING SEARCH STRATEGIES IN COMPUTERIZED INFORMATION RETRIEVAL SYSTEMS

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    A recent trend in information retrieval systems technology is the development of on-line information retrieval systems. One objective of these systems has been to attempt to enhance decision effectiveness by allowing users to preferentially seek information, thereby facilitating the reduction or elimination of information overload. Since information systems users may preferentially seek information to confirm their initial beliefs, decision making effectiveness may be dependent on the accuracy of the decision maker\u27s initial hypothesis of causality. The basic research question addressed in this paper is: Will the use of a knowledge-based DSS (KBDSS), designed to search for and present both confirming and disconfirming evidence, result in enhanced decision effectiveness? To assess the effect of information retrieval system type on decision effectiveness, a laboratory experiment was conducted in which participants were required to make an initial attribution of causality for a problem, to query either a conventional on-line information retrieval system or a KBDSS for additional information, and then to make a final attribution of causality. The conclusions reached from this experiment provide constructive guidance for information systems designers in overcoming the concept known as confirmation bias, that tendency to seek information that confirms the user\u27s first impression

    Medicine is not science

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    ABSTRACT: Abstract Most modern knowledge is not science. The physical sciences have successfully validated theories to infer they can be used universally to predict in previously unexperienced circumstances. According to the conventional conception of science such inferences are falsified by a single irregular outcome. And verification is by the scientific method which requires strict regularity of outcome and establishes cause and effect. Medicine, medical research and many ā€œsoftā€ sciences are concerned with individual people in complex heterogeneous populations. These populations cannot be tested to demonstrate strict regularity of outcome in every individual. Neither randomised controlled trials nor observational studies in medicine are science in the conventional conception. Establishing and using medical and other ā€œsoft scienceā€ theories cannot be scientific. It requires conceptually different means: requiring expert judgement applying all available evidence in the relevant available factual matrix. The practice of medicine is observational. Prediction of outcomes for the individual requires professional expertise applying available medical knowledge and evidence. Expertise in any profession can only be acquired through experience. Prior cases are the fundament of knowledge and expertise in medicine. Case histories, studies and series can provide knowledge of extremely high reliability applicable to establishing reliable general theories and falsifying others. Their collation, study and analysis should be a priority in medicine. Their devaluation as evidence, the failure to apply their lessons, the devaluation of expert professional judgement and the attempt to emulate the scientific method are all historic errors in the theory and practice of modern medicine
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