3,195 research outputs found
A deterministic algorithm for experimental design applied to tomographic and microseismic monitoring surveys
SUMMARY
Most general experimental design algorithms are either: (i) stochastic and hence give different
designs each time they are run with finite computing power, or (ii) deterministic but converge
to results that depend on an initial or reference design, taking little or no account of the range
of all other possible designs. In this paper we introduce an approximation to standard measures
of experimental design quality that enables a new algorithm to be used. The algorithm
is simple, deterministic and the resulting experimental design is influenced by the full range
of possible designs, thus addressing problems (i) and (ii) above. Although the designs produced
are not guaranteed to be globally optimal, they significantly increase the magnitude of
small eigenvalues in the model–data relationship (without requiring that these eigenvalues be
calculated). This reduces the model uncertainties expected post-experiment. We illustrate the
method on simple tomographic and microseismic location examples with varying degrees of
seismic attenuation
Time-Series Evidence of the Effect of the Minimum Wage on Youth Employment and Unemployment
While previous time series studies have quite consistently found that the minimum wage reduces teenage employment, the extent of this reduction is much less certain. Moreover, because few previous studies report results of more than one specification, the causes of differences in estimated impacts are not well understood. Less consensus is evident on the effect of the minimum wage on teenage unemployment, or its relative impact on black and white teenagers. The purpose of this paper is both to update earlier work and to analyze the sensitivity of estimated minimum wage effects to alternative specification choices. In addition to providing estimates of the effect of minimum wage increases on aggregate employment and unemployment rates of teenagers, we explore several related issues: the relative importance of changing the level and coverage of the minimum wage; the timing of responses to a change in the minimum; effects on part-time and full-time work; effects on young adults (age 20-24).
The Effect of the Minimum Wage on Employment and Unemployment: A Survey
In this paper, we survey theoretical models of the effect of the minimum wage and, in somewhat greater detail, evidence of its effect on employment and unemployment. Our discussion of the theory emphasizes recent work using two-sector and heterogeneous-worker models. We then summarize and evaluate the large literature on employment and unemployment effects of the minimum on teenagers. Finally, we survey the evidence of the effect of the minimum wage on adult employment, and on employment in low-wage industries and areas.
An adaptive neuro-fuzzy propagation model for LoRaWAN
This article proposes an adaptive-network-based fuzzy inference system (ANFIS) model for accurate estimation of signal propagation using LoRaWAN. By using ANFIS, the basic knowledge of propagation is embedded into the proposed model. This reduces the training complexity of artificial neural network (ANN)-based models. Therefore, the size of the training dataset is reduced by 70% compared to an ANN model. The proposed model consists of an efficient clustering method to identify the optimum number of the fuzzy nodes to avoid overfitting, and a hybrid training algorithm to train and optimize the ANFIS parameters. Finally, the proposed model is benchmarked with extensive practical data, where superior accuracy is achieved compared to deterministic models, and better generalization is attained compared to ANN models. The proposed model outperforms the nondeterministic models in terms of accuracy, has the flexibility to account for new modeling parameters, is easier to use as it does not require a model for propagation environment, is resistant to data collection inaccuracies and uncertain environmental information, has excellent generalization capability, and features a knowledge-based implementation that alleviates the training process. This work will facilitate network planning and propagation prediction in complex scenarios
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Re-reading the Gospel of Luke today : from a first century urban writing site to a twentieth century urban reading site
Postmodern theorising has presented the reader as an active agent in the process of the interpretation of texts. Sociology of knowledge approaches have identified both the author and the reader of texts as socially embodied within a context. This study presents a unique collection of readings in the Gospel of Luke by ordinary real-readers from a disadvantaged and/or marginalised social and ecclesial location, within an affluent first world context. These readings, transcribed in Volume Two, present empirical reader research for analysis, through dialogue and conversation with professional readings in the Gospel of Luke, in order to assess what contribution the former might make to contemporary hermeneutics. Identifying contemporary human experience of ordinary real-readers as the starting point in their reading of the Lukan text, the study illustrates how these readings act as a useful tool of suspicion in conversation with readings that claim to be objective and value-neutral, and how they facilitate critical reflection on the ideological and theological commitments of the dominant classes in society and church. The value and legitimacy of the readings of ordinary real-readers is discussed, and how their social and ecclesial marginalisation and disadvantage provides a nontotalising presence in biblical interpretation, a presence that guards against the claims of permanence made by those in the academic and ecclesial world. Identification of contemporary human experience as inevitably influencing the process of interpretation leads to a consideration of the place of the historical critical paradigm in biblical studies. The value and legitimacy of ordinary real readers as active agents in the process of interpretation, and the contribution they make to contemporary hermeneutics, requires a consideration of safeguards against reading anarchy. The process of self and social analysis, and an openness to dialogue and conversation with those outside our own contexts, including our ancestors in the faith, is considered as a way forward, utilising ordinary and professional real-readers in the ongoing process of biblical interpretation
Characterization and evaluation of the microcantilever radiation detector
In this study, a microcantilever charged-particle detector was characterized and evaluated. The method employed involved sensing an electric field emanating from a small collector plate on which charge built up to charged-particle flux.Sensitivity to alpha particles was determined using frequency and damping rate parameter shifts. Alpha particle detection experiments were compared to experiments using a charged plate of fixed voltage in order to characterize response more fully and to identify differences between expected charge accumulation and actual accumulation. Changes in cantilever behavior resulting from changes in ambient environmental conditions were also studied in order to determine to what extent they would impact charged-particle detection. In particular, microcantilever tip-surface adhesion force and jump-to-contact distance were studied as a function of relative humidity, and the dynamics of the liquid neck extending between the micro cantilever tip and the surface at small separation distances were investigated. In addition, relationship between the angle of the microcantilever tip relative to the surface and the excitation of multiple resonance modes was identified and described
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