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

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

Three-dimensional visualization of cultural clusters in the 1878 yellow fever epidemic of New Orleans

<p>Abstract</p> <p>Background</p> <p>An epidemic may exhibit different spatial patterns with a change in geographic scale, with each scale having different conduits and impediments to disease spread. Mapping disease at each of these scales often reveals different cluster patterns. This paper will consider this change of geographic scale in an analysis of yellow fever deaths for New Orleans in 1878. Global clustering for the whole city, will be followed by a focus on the French Quarter, then clusters of that area, and finally street-level patterns of a single cluster. The three-dimensional visualization capabilities of a GIS will be used as part of a cluster creation process that incorporates physical buildings in calculating mortality-to-mortality distance. Including nativity of the deceased will also capture cultural connection.</p> <p>Results</p> <p>Twenty-two yellow fever clusters were identified for the French Quarter. These generally mirror the results of other global cluster and density surfaces created for the entire epidemic in New Orleans. However, the addition of building-distance, and disease specific time frame between deaths reveal that disease spread contains a cultural component. Same nativity mortality clusters emerge in a similar time frame irrespective of proximity. Italian nativity mortalities were far more densely grouped than any of the other cohorts. A final examination of mortalities for one of the nativity clusters reveals that further sub-division is present, and that this pattern would only be revealed at this scale (street level) of investigation.</p> <p>Conclusion</p> <p>Disease spread in an epidemic is complex resulting from a combination of geographic distance, geographic distance with specific connection to the built environment, disease-specific time frame between deaths, impediments such as herd immunity, and social or cultural connection. This research has shown that the importance of cultural connection may be more important than simple proximity, which in turn might mean traditional quarantine measures should be re-evaluated.</p

Advances in image acquisition and filtering for MRI neuroimaging at 7 tesla

Performing magnetic resonance imaging at high magnetic field strength promises many improvements over low fields that are of direct benefit in functional neuroimaging. This includes the possibility of improved signal-to-noise levels, and increased BOLD functional contrast and spatial specificity. However, human MRI at 7T and above suffers from unique engineering challenges that limit the achievable gains. In this thesis, three technological developments are introduced, all of which address separate issues associated with functional magnetic resonance neuroimaging at very high magnetic field strengths. First, the image homogeneity problem is addressed by investigating methods of RF shimming — modifying the excitation portion of the MRI experiment for use with multi-channel RF coils. It is demonstrated that in 2D MRI experiments, shimming on a slice-by slice basis allows utilization of an extra degree of freedom available from the slice dimension, resulting in significant gains in image homogeneity and reduced RF power requirements. After acceptable images are available, we move to address complications of high field imaging that manifest in the fMRI time series. In the second paper, the increased physiological noise present in BOLD time series at high field is addressed with a unique data-driven noise regressor scheme based upon information in the phase component of the MRI signal. It is demonstrated that this method identifies and removes a significant portion of physiological signals, and performs as good or better than other popular data driven methods that use only the magnitude signal information. Lastly, the BOLD phase signal is again leveraged to address the confounding role of veins in resting state BOLD fMRI experiments. The phase regressor technique (previously developed by Dr. Menon) is modified and applied to resting state fMRI to remove macro vascular contributions in the datasets, leading to changes in spatial extent and connectivity of common resting state networks on single subjects and at the group level