Using Behavioral Theories of Choice to Predict Drinking Outcomes Following a Brief Intervention.

Behavioral theories of choice predict that substance use is partly a function of the relative value of drugs in relation to other available reinforcers. This study evaluated this hypothesis in the context of predicting drinking outcomes following an alcohol abuse intervention. Participants (N=54, 69% female, 31% male) were college student heavy drinkers who completed a single-session motivational intervention. Students completed a baseline measure of substance-related and substance-free activity participation and enjoyment. Only women showed a significant reduction in drinking at the 6-month follow-up, and the ratio of substance-related to substance-free reinforcement accounted for unique variance in their drinking outcomes. Women who at baseline derived a smaller proportion of their total reinforcement from substance use showed lower levels of follow-up drinking, even after the authors controlled for baseline drinking level. Male and female participants who reduced their drinking showed increased proportional reinforcement from substance-free activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability of formation control using a consensus protocol under directed communications with two time delays and delay scheduling

We consider a linear algorithm to achieve formation control in a group of agents which are driven by second-order dynamics and affected by two rationally independent delays. One of the delays is in the position and the other in the velocity information channels. These delays are taken as constant and uniform throughout the system. The communication topology is assumed to be directed and fixed. The formation is attained by adding a supplementary control term to the stabilising consensus protocol. In preparation for the formation control logic, we first study the stability of the consensus, using the recent cluster treatment of characteristic roots (CTCR) paradigm. This effort results in a unique depiction of the non-conservative stability boundaries in the domain of the delays. However, CTCR requires the knowledge of the potential stability switching loci exhaustively within this domain. The creation of these loci is done in a new surrogate coordinate system, called the ‘spectral delay space (SDS)’. The relative stability is also investigated, which has to do with the speed of reaching consensus. This step leads to a paradoxical control design concept, called the ‘delay scheduling’, which highlights the fact that the group behaviour may be enhanced by increasing the delays. These steps lead to a control strategy to establish a desired group formation that guarantees spacing among the agents. Example case studies are presented to validate the underlying analytical derivations.     

An extended/generalized phase-field finite element method for crack growth with global-local enrichment

An extended/generalized finite element method (XFEM/GFEM) for simulating quasistatic crack growth based on a phase-field method is presented. The method relies on approximations to solutions associated with two different scales: a global scale, that is, structural and discretized with a coarse mesh, and a local scale encapsulating the fractured region, that is, discretized with a fine mesh. A stable XFEM/GFEM is employed to embed the displacement and damage fields at the global scale. The proposed method accommodates approximation spaces that evolve between load steps, while preserving a fixed background mesh for the structural problem. In addition, a prediction-correction algorithm is employed to facilitate the dynamic evolution of the confined crack regions within a load step. Several numerical examples of benchmark problems in two- and three-dimensional quasistatic fracture are provided to demonstrate the approach.     

Diffraction of horizontally polarized ultrasonic plane waves on a periodically corrugated solid-liquid interface for normal incidence and Brewster angle incidence

The theory, and the use at normal incidence, of shear-vertically polarized waves (with polarization vector in the plane containing the incident wave vector and the normal on the interface) using the mode conversion method has been tackled by others. Here we develop the theory for shear-horizontally polarized incident waves (with polarization vector perpendicular to both the normal on the interface and the incoming wave vector). We take into account normal incidence as well as oblique incidence. For normal incidence, we discover the generation of Love waves. If oblique incidence is considered, we discover the existence of a Brewster angle of incidence, comparable with the Brewster angle in optics, in which a diffraction grating can be used as a polarization filter.     

Efficient Mercury Capture Using Functionalized Porous Organic Polymer

The primary challenge in materials design and synthesis is achieving the balance between performance and economy for real‐world application. This issue is addressed by creating a thiol functionalized porous organic polymer (POP) using simple free radical polymerization techniques to prepare a cost‐effective material with a high density of chelating sites designed for mercury capture and therefore environmental remediation. The resulting POP is able to remove aqueous and airborne mercury with uptake capacities of 1216 and 630 mg g^?1, respectively. The material demonstrates rapid kinetics, capable of dropping the mercury concentration from 5 ppm to 1 ppb, lower than the US Environmental Protection Agency's drinking water limit (2 ppb), within 10 min. Furthermore, the material has the added benefits of recyclability, stability in a broad pH range, and selectivity for toxic metals. These results are attributed to the material's physical properties, which include hierarchical porosity, a high density of chelating sites, and the material's robustness, which improve the thiol availability to bind with mercury as determined by X‐ray photoelectron spectroscopy and X‐ray absorption fine structure studies. The work provides promising results for POPs as an economical material for multiple environmental remediation applications.     

Minerva: sequential covering for rule extraction.

Various benchmarking studies have shown that artificial neural networks and support vector machines often have superior performance when compared to more traditional machine learning techniques. The main resistance against these newer techniques is based on their lack of interpretability: it is difficult for the human analyst to understand the reasoning behind these models' decisions. Various rule extraction (RE) techniques have been proposed to overcome this opacity restriction. These techniques are able to represent the behavior of the complex model with a set of easily understandable rules. However, most of the existing RE techniques can only be applied under limited circumstances, e.g., they assume that all inputs are categorical or can only be applied if the black-box model is a neural network. In this paper, we present Minerva, which is a new algorithm for RE. The main advantage of Minerva is its ability to extract a set of rules from any type of black-box model. Experiments show that the extracted models perform well in comparison with various other rule and decision tree learners.     

An integrative model of trust on IT outsourcing: Examining a bilateral perspective

Trust has been considered a central aspect of successful IT outsourcing. Although a great deal of interest in trust has been described, there are very few theoretical models in the IT outsourcing literature to explain mutual trust, its role, and its impact in IT outsourcing. This study proposes a trust-based relationship research model to assess the perceived IT outsourcing success in terms of (1) mutual trust with its temporal dimension of initial trust and initial distrust, and (2) knowledge sharing with the moderating effect of mutual dependency. This model was then validated and applied in a study involving organizations in Korea. The data was collected and analyzed to understand initial trust, initial distrust, knowledge sharing, and mutual dependency as contributing factors to success in IT outsourcing. The results show that mutual trust between the service receiver and provider is very important for knowledge sharing and outsourcing success, and is affected by the initial perception to each other’s partner at the beginning of the outsourcing process. Interestingly, this study also shows that initial trust is considered a significant factor in the perception of mutual trust from the service receiver’s perspective, but not from the service provider’s viewpoint. The results help extend our understanding of critical success factors in outsourcing success and of different standpoints between the service receiver and provider.

模型过程差异下的ALSTOM气化装置控制结构选择(英文)

相对扰动增益矩阵是分析控制结构抗干扰性的一个有用工具,但它的结果受模型不确定性影响.提出基于优化来确定相对扰动增益矩阵范围的方法并用来选择ALSTOM气化装置的控制结构.利用过程运行仿真数据和输出误差系统辨识方法得到降阶线性模型.在不同运行状况统辨几个模型并通过这些模型得到模型不确定性范围.计算出ALSTOM气化装置在模型不确定性下的广义相对扰动增益范围并用来选择鲁棒控制结构.