141,114 research outputs found

    Discursive design thinking: the role of explicit knowledge in creative architectural design reasoning

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    The main hypothesis investigated in this paper is based upon the suggestion that the discursive reasoning in architecture supported by an explicit knowledge of spatial configurations can enhance both design productivity and the intelligibility of design solutions. The study consists of an examination of an architect’s performance while solving intuitively a well-defined problem followed by an analysis of the spatial structure of their design solutions. One group of architects will attempt to solve the design problem logically, rationalizing their design decisions by implementing their explicit knowledge of spatial configurations. The other group will use an implicit form of such knowledge arising from their architectural education to reason about their design acts. An integrated model of protocol analysis combining linkography and macroscopic coding is used to analyze the design processes. The resulting design outcomes will be evaluated quantitatively in terms of their spatial configurations. The analysis appears to show that an explicit knowledge of the rules of spatial configurations, as possessed by the first group of architects can partially enhance their function-driven judgment producing permeable and well-structured spaces. These findings are particularly significant as they imply that an explicit rather than an implicit knowledge of the fundamental rules that make a layout possible can lead to a considerable improvement in both the design process and product. This suggests that by externalizing th

    Investigating the effect of solid boundaries on the gas molecular mean-free-path

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    A key parameter for micro-gas-flows, the mean free path, is investigated in this paper. The mean free path is used in various models for predicting micro gas flows, both in the governing equations and their boundary conditions. The conventional definition of the mean free path is based on the assumption that only binary collisions occur and is commonly described using the macroscopic quantities density, viscosity and temperature. In this paper we compare the prediction by this definition of the mean free paths for helium, neon and argon gases under standard temperature and pressure conditions, with the mean free paths achieved by measurements of individual molecules using the numerical simulation technique of molecular dynamics. Our simulation using molecular dynamics consists of a cube with six periodic boundary conditions, allowing us to simulate an unconfined gas “package”. Although, the size of this package is important, since its impact on computational cost is considerable, it is also important to have enough simulated molecules to average data from. We find that the molecular dynamics method using 20520 simulated molecules yields results that are within 1% accuracy from the conventional definition of the mean free paths for neon and argon and within 2.5% for helium. We can also conclude that the normal approximation of only considering binary collisions is seemingly adequate for these gases under standard temperature and pressure conditions. We introduce a single planar wall and two parallel planar walls to the simulated gas of neon and record the mean free paths at various distances to the walls. It is found that the mean free paths affected by molecular collisions with the walls corresponds well with theoretical models up to Knudsen numbers of 0.2

    An Empirical Study of Employment Arbitration: Case Outcomes and Processes

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    Using data from reports filed by the American Arbitration Association (AAA) pursuant to California Code requirements, this article examines outcomes of employment arbitration. The study analyzes 3,945 arbitration cases, of which 1,213 were decided by an award after a hearing, filed and reaching disposition between January 1, 2003 and December 31, 2007. This includes all the employment arbitration cases administered nationally by the AAA during this time period that derived from employer-promulgated arbitration procedures. Key findings include: (1) the employee win rate amongst the cases was 21.4%, which is lower than employee win rates reported in employment litigation trials; (2) in cases won by employees, the median award amount was 36,500andthemeanwas36,500 and the mean was 109,858, both of which are substantially lower than award amounts reported in employment litigation; (3) mean time to disposition in arbitration was 284.4 days for cases that settled and 361.5 days for cases decided after a hearing, which is substantially shorter than times to disposition in litigation; (4) mean arbitration fees were 6,340percaseoverall,6,340 per case overall, 11,070 for cases disposed of by an award following a hearing, and in 97 percent of these cases the employer paid 100 percent of the arbitration fees beyond a small filing fee, pursuant to AAA procedures; (5) in 82.4 percent of the cases, the employees involved made less than 100,000peryear;and(6)themeanamountclaimedwas100,000 per year; and (6) the mean amount claimed was 844,814 and 75 percent of all claims were greater than $36,000. The study also analyzes whether there is a repeat player effect in employer arbitration. The results provide strong evidence of a repeat employer effect in which employee win rates and award amounts are significantly lower where the employer is involved in multiple arbitration cases, which could be explained by various advantages accruing to larger organizations with greater resources and expertise in dispute resolution procedures. The results also indicate the existence of a significant repeat employer-arbitrator pairing effect in which employees on average have lower win rates and receive smaller damage awards where the same arbitrator is involved in more than one case with the same employer, a finding supporting some of the fairness criticisms directed at mandatory employment arbitration

    On Cognitive Preferences and the Plausibility of Rule-based Models

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    It is conventional wisdom in machine learning and data mining that logical models such as rule sets are more interpretable than other models, and that among such rule-based models, simpler models are more interpretable than more complex ones. In this position paper, we question this latter assumption by focusing on one particular aspect of interpretability, namely the plausibility of models. Roughly speaking, we equate the plausibility of a model with the likeliness that a user accepts it as an explanation for a prediction. In particular, we argue that, all other things being equal, longer explanations may be more convincing than shorter ones, and that the predominant bias for shorter models, which is typically necessary for learning powerful discriminative models, may not be suitable when it comes to user acceptance of the learned models. To that end, we first recapitulate evidence for and against this postulate, and then report the results of an evaluation in a crowd-sourcing study based on about 3.000 judgments. The results do not reveal a strong preference for simple rules, whereas we can observe a weak preference for longer rules in some domains. We then relate these results to well-known cognitive biases such as the conjunction fallacy, the representative heuristic, or the recogition heuristic, and investigate their relation to rule length and plausibility.Comment: V4: Another rewrite of section on interpretability to clarify focus on plausibility and relation to interpretability, comprehensibility, and justifiabilit

    Requirements for contractility in disordered cytoskeletal bundles

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    Actomyosin contractility is essential for biological force generation, and is well understood in highly organized structures such as striated muscle. Additionally, actomyosin bundles devoid of this organization are known to contract both in vivo and in vitro, which cannot be described by standard muscle models. To narrow down the search for possible contraction mechanisms in these systems, we investigate their microscopic symmetries. We show that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. This suggests a role for filament buckling in the contraction of these bundles, consistent with recent experimental results on reconstituted actomyosin bundles.Comment: 10 pages, 6 figures; text shortene

    When do we stop digging? Conditions on a fundamental theory of physics

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    In seeking an answer to the question of what it means for a theory to be fundamental, it is enlightening to ask why the current best theories of physics are not generally believed to be fundamental. This reveals a set of conditions that a theory of physics must satisfy in order to be considered fundamental. Physics aspires to describe ever deeper levels of reality, which may be without end. Ultimately, at any stage we may not be able to tell whether we've reached rock bottom, or even if there is a base level – nevertheless, I draft a checklist to help us identify when to stop digging, in the case where we may have reached a candidate for a final theory. Given that the list is – according to (current) mainstream belief in high-energy physics – complete, and each criterion well-motivated, I argue that a physical theory that satisfies all the criteria can be assumed to be fundamental in the absence of evidence to the contrary (i.e., I argue that the necessary conditions are jointly sufficient for a claim of fundamentality in physics)
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