1,117 research outputs found
Machine learning stochastic design models.
Due to the fluid nature of the early stages of the design process, it is difficult to obtain deterministic product design evaluations. This is primarily due to the flexibility of the design at this stage, namely that there can be multiple interpretations of a single design concept. However, it is important for designers to understand how these design concepts are likely to fulfil the original specification, thus enabling the designer to select or bias towards solutions with favourable outcomes. One approach is to create a stochastic model of the design domain. This paper tackles the issues of using a product database to induce a Bayesian model that represents the relationships between the design parameters and characteristics. A greedy learning algorithm is presented and illustrated using a simple case study
Development of a simple information pump.
The Information Pump (IP) is a methodology that aims to counter the problems arising from traditional subjective product data collection. The IP is a game theory based process that aims to maximise information extracted from a panel of subjects, while maintaining their interest in the process through a continuous panelist scoring method. The challenge with implementing this arises from the difficulty in executing the 'game'. In its original format, there is an assumption that the game is played with each player using their own PC to interact with the process. While this in theory allows information and scores to flow in a controlled manner between the players, it actually provides a major barrier to the wider adoption of the IP method. This barrier is two-fold: it is costly and complex, and it is not a natural manner for exchanging information. The core objective is to develop a low cost version of the IP method. This will use the game theory approach to maintain interest among participants and maximise information extraction, but remove the need for each participant to have their own PC interface to the game. This will require replacing both the inter-player communication method and the score keeping/reporting
Reproducing neutrino effects on the matter power spectrum through a degenerate Fermi gas approach
Modifications on the predictions about the matter power spectrum based on the
hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid
to some dominant cosmological scenario are investigated. Reporting about the
systematic way of accounting for all the cosmological perturbations, through
the Boltzmann equation we obtain the analytical results for density
fluctuation, , and fluid velocity divergence, , of the DFG.
Small contributions to the matter power spectrum are analytically obtained for
the radiation-dominated background, through an ultra-relativistic
approximation, and for the matter-dominated and -dominated eras,
through a non-relativistic approximation. The results can be numerically
reproduced and compared with those of considering non-relativistic and
ultra-relativistic neutrinos into the computation of the matter power spectrum.
Lessons concerning the formation of large scale structures of a DFG are
depicted, and consequent deviations from standard CDM predictions for
the matter power spectrum (with and without neutrinos) are quantified.Comment: 28 pages, 06 figure
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Turning the Sword: How NPD Teams Cope with Front-End Tensions
Front-end new product development (NPD) is fraught with tensions that fuel and inhibit innovation. According to paradox theory, tensions pose a double-edged sword, sparking learning and creativity or anxiety and counterproductive responses. NPD teams' shared understandings—how they think about (cognition) and approach (motivation) tensions—turn the sword. Existing literature examines innovation tensions and their management. Yet scholars call for deeper dives, seeking research that unpacks cognitive and motivational drivers underlying how NPD teams cope with tensions. This paper responds, presenting a four-year inductive study of five NPD consultancies. Across cases, findings explicate the roles of paradoxical cognitive frames and regulatory motivational focus. Across firms, the front-end NPD teams framed tensions paradoxically. Three frames—guided freefall, benevolent dictatorship, and cohesive diversity—helped teams develop shared understandings of tensions as paradoxical, posing competing yet interdependent demands. Teams varied, however, in their regulatory focus, influencing how they applied the frames to approach tensions. In the most innovative case, teams applied a promotion focus, energized to explore tensions in search of more creative alternatives and synergies. In less innovative cases, teams applied a prevention focus, motivated to avoid risk and loss. Together, paradoxical frames and regulatory focus shaped teams' coping behaviors and resulting innovation. Resulting theory posits the interplay among cognitive, motivational, and behavioral drivers of innovation. Results offer three contributions. First, this study extends understanding of antecedents to team innovation and front-end NPD. Second, findings deepen insights into team cognition and paradoxical frames. Last, the theoretical framework explicates how cognitive-motivational interactions enable coping behaviors that foster innovation. The conclusion poses managerial and research implications. Building from paradox theory this study suggests means to foster shared paradoxical frames and promotion focus in NPD teams. Further, study limitations highlight opportunities to extend its generalizability and elaborate underlying drivers of innovation
Single-phase laminar flow heat transfer from confined electron beam enhanced surfaces
An experimental investigation of the thermal-hydraulic characteristics for single-phase flow through three electron beam enhanced structures was conducted with water at mass flow rates from 0.005 kg/s to 0.045 kg/s. The structures featured copper heat transfer surfaces, approximately 28 mm wide and 32 mm long in the flow direction, with complex three-dimensional (3D) electron beam manufactured pyramid-like structures. The channel height varied depending on the height of the protrusions and the tip clearance was maintained at 0.1-0.3 mm. The average protrusion densities for the three samples S1, S2, and S3 were 13, 11, and 25 per cm2 with protrusion heights of 2.5, 2.8, and 1.6 mm, respectively. The data gathered were compared to those for a smooth channel surface operating under similar conditions. The results show an increase up to approximately three times for the average Nusselt number compared with the smooth surface. This is attributed to the surface irregularities of the enhanced surfaces, which not only increase the heat transfer area but also improve mixing, disturb the thermal and velocity boundary layers, and reduce thermal resistance. The increase in heat transfer with the enhanced surfaces was accompanied by an increase of pressure drop, which has to be considered in design.The authors would like to acknowledge Dr Anita Buxton and Dr Bruce Dance of TWI for their contribution to this project and also EPSRC and TSB for funding the EngD programme and sponsoring the ASTIA collaborative research project that helped to develop the Electron Beam enhanced surfaces respectively
Coronary blood flow measured by the Xenon-133 washout technique
Coronary blood flow was measured by the radioactive xenon (133Xe) washout technique in 13 subjects: 6 controls, 5 patients with coronary artery disease and 2 patients who had undergone aortocoronary saphenous vein bypass grafts. The method did not discriminate between normal subjects and patients with coronary artery disease, but may be useful to the study of blood flow in coronary bypass grafts. In 2 patients changes in coronary flow were associated with a change in the patient's clinical status.S. Afr. Med. J., 48, 175 (1974)
Mid-Miocene cooling and the extinction of tundra in continental Antarctica
A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition
Parental Attitudes and Their Influence on the Medical Management of Diabetic Adolescents
Competent professional assistance can meet the challenges of keeping parents and patients on a stable and sound emotional course as the diabetic adolescent grows up.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66551/2/10.1177_000992287000900814.pd
Exomoon simulations
We introduce and describe our newly developed code that simulates light
curves and radial velocity curves for arbitrary transiting exoplanets with a
satellite. The most important feature of the program is the calculation of
radial velocity curves and the Rossiter-McLaughlin effect in such systems. We
discuss the possibilities for detecting the exomoons taking the abilities of
Extremely Large Telescopes into account. We show that satellites may be
detected also by their RM effect in the future, probably using less accurate
measurements than promised by the current instrumental developments. Thus, RM
effect will be an important observational tool in the exploration of exomoons.Comment: 5 pages, 2 figures with 9 figure panels, accepted by EM&
Physical tests for Random Numbers in Simulations
We propose three physical tests to measure correlations in random numbers
used in Monte Carlo simulations. The first test uses autocorrelation times of
certain physical quantities when the Ising model is simulated with the Wolff
algorithm. The second test is based on random walks, and the third on blocks of
n successive numbers. We apply the tests to show that recent errors in high
precision simulations using generalized feedback shift register algorithms are
due to short range correlations in random number sequences. We also determine
the length of these correlations.Comment: 16 pages, Post Script file, HU-TFT-94-
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