Network lifetime maximization with cross-layer design in wireless sensor networks

This paper investigates a cross-layer design approach for minimizing energy consumption and maximizing network lifetime (NL) of a multiple-source and single-sink (MSSS) WSN with energy constraints. The optimization problem for MSSS WSN can be formulated as a mixed integer convex optimization problem with the adoption of time division multiple access (TDMA) in medium access control (MAC) layer, and it becomes a convex problem by relaxing the integer constraint on time slots. Impacts of data rate, link access and routing are jointly taken into account in the optimization problem formulation. Both linear and planar network topologies are considered for NL maximization (NLM). With linear MSSS and planar single-source and single-sink (SSSS) topologies, we successfully use Karush-Kuhn-Tucker (KKT) optimality conditions to derive analytical expressions of the optimal NL when all nodes are exhausted simultaneously. The problem for planar MSSS topology is more complicated, and a decomposition and combination (D&C) approach is proposed to compute suboptimal solutions. An analytical expression of the suboptimal NL is derived for a small scale planar network. To deal with larger scale planar network, an iterative algorithm is proposed for the D&C approach. Numerical results show that the upper-bounds of the network lifetime obtained by our proposed optimization models are tight. Important insights into the NL and benefits of cross-layer design for WSN NLM are obtained.

A cross-national investigation into the marketing department's influence within the firm:toward initial empirical generalizations

An ongoing strong debate within the marketing discipline concerns the role of marketing within the firm. It has been frequently reported that the marketing function is in a deep decline. Marketing executives and academics alike are interested in the antecedents of this decline and potential performance consequences of this decline. Recent academic research have started investigations on this important topic. Using studies in single countries innovativeness and accountability of the marketing department has been reported as major antecedents of the influence of the marketing department within the organization. Academic research, however, does not provide convincing evidence for a direct link between this influence and business performance. Instead it shows that market orientation is a crucial intervening variable, as marketing department influence is positively related market orientation, which subsequently positively related to business performance. As noted prior research, however, studies firms in single countries. In this article we execute a cross-national study on the antecedents and performance consequences of marketing department influence in order to derive initial empirical generalizations. This study is executed in seven Western-oriented countries, including USA, UK, The Netherlands, Germany, Sweden, Israel and Australia. The study heavily builds on the framework developed in the 2009 Journal of Marketing article of Verhoef and Leeflang. This framework is tested per country and subsequently meta-analytic tests are used to derive initial empirical generalizations. An important empirical generalization is that innovativeness, the customer-connecting capabilities, and accountability of the marketing department are positively related to marketing department influence. Interestingly, a second initial generalization is that creativity of the marketing negative induces less influence. Our results also show a third empirical generalization in that firms having a CEO with a marketing background tend to have more influential marketing departments. Confirming prior research a fourth initial empirical generalization is that MD influence measures and market orientation are positively related. Market orientation is subsequently positively related to business performance. Our most important generalization is, however, that MD influence is positively related to business performance. Hence, beyond striving to become market oriented, firms should also aim to have strong marketing departments. These departments can create a stronger focus on the customer and can also coordinate marketing efforts. In order to become more influential marketing departments should: (1) acquire innovative capabilities, (2) be more connected to customers, (3) invest in accountability, and (4) be careful with be careful being too creative.

Creative self-efficacy and individual creativity in teams:cross-level interactions with team informational resources

We propose a cross-level perspective on the relation between creative self-efficacy and individual creativity in which team informational resources, comprising both shared “knowledge of who knows what” (KWKW) and functional background diversity, benefit the creativity of individuals more with higher creative self-efficacy. To test our hypotheses, we conducted a multi-level study with 176 employees working in 34 research and development teams of a multinational company in 4 countries. In support of our hypotheses, the link between creative self-efficacy and individual creativity was more positive with greater shared KWKW, and this interactive effect was pronounced for teams of high rather than low functional background diversity. We discuss implications for the study of creative self-efficacy in team contexts. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Chain-link based HVDC voltage source converter using current injection

VSC converters are becoming more prevalent for HVDC applications. Two circuits are commercially available at present, a traditional six-switch, PWM inverter, implemented using series connected IGBTs - ABBs HVDC Light®, and the other a modular multi-level converter (MMC) - Siemens HVDC-PLUS. This paper presents an alternative MMC topology, which utilises a novel current injection technique, and exhibits several desirable characteristics.

Antecedents and consequences of percieved effective managerial coaching:an individual, team-level and cross-level examination

The major contribution of the study is the identification of a positive link between perceived effective managerial coaching (PEMC) and team task performance and also, the examination of PEMC adopting a multilevel research design and incorporating dual-source data. Specifically, drawing on social psychology, the thesis aims at developing and testing a comprehensive conceptual framework of the antecedents and consequences of PEMC for knowledge workers. The model takes into consideration intrapersonal, interpersonal and team-level characteristics, which relate to PEMC and, subsequently associate with important work outcomes. In this regard, the thesis identifies PEMC as a practice of dual nature in that it may be experienced not only as a one-on-one workplace developmental interaction, but also as a managerial practice that is experienced by each member of a team for co-ordination purposes. Adopting a cross-sectional survey research design, the hypotheses are tested in three organisations in Greece and the UK. In particular, hierarchical linear modelling of 191 employees nested in 60 teams yields that employees’ learning goal orientation (LGO) and high-quality exchanges between an employee and a manager (LMX) are positively related to effective MC, while a manager’s LGO moderates the relationship between employees’ LGO and PEMC. In turn, PEMC, as a one-on-one practice, is related to cognitive outcomes, such as information sharing, while as a shared team practice is related also to behavioural outcomes, including individual and team performance. Overall, the study contributes to a growing body of coaching and management literature that acknowledges PEMC as a core managerial practice.

How education should link with career paths

How good is your pharmacy practice? And what does “good” look like? Take a look back at the education and training you have received in your career to date. Has it stood you in good stead? Certainly there is a need to establish a model of professional education and development that produces good pharmacists — you should be able to demonstrate your competence regardless of your sector of work. It may help if we move away from the view that excellence in pharmacy practice is primarily defined by where you practise and the kind of job that you do. The Modernising Pharmacy Careers programme’s aspirations to integrate the undergraduate degree with the preregistration training year are bold and to be applauded — provided the outcome delivers changes that are more than superficial. The new model needs to deliver greater integration of education with practice, while retaining an adequate science base. Theory should be put into the context of practice-based, cross-sector learning needs and opportunities. For example, is the classroom really the best environment in which to learn dispensing? Pharmacokinetic theory could be put into context through creatively designed work placements. And it might make more sense to learn patient counselling in a community pharmacy, and so on. Is it resources we lack to make this happen? Or do we lack the collective will to be imaginative, to be radical and to conceive new approaches to professional education? Implicit in this new approach to education is the expectation that pharmacists should teach and mentor and, conversely, that those who teach should also engage in relevant practice. University education must produce graduates whose knowledge and competence are useful to employers. Moreover, graduates must be adequately prepared to enter any area of the profession endowed with professional self-confidence (something, arguably, that needs further development within the pharmacy psyche). Of course, becoming qualified is just the beginning. Post-qualification, pharmacists need structured career paths that foster this professional confidence, support learning and ensure recognition. To this end, the Royal Pharmaceutical Society-led professional curriculum group is working to define knowledge, skills and experience for all areas of advanced practice. More than ever, the profession needs to adopt a culture of learning, teaching and practice research that is unified. The question is: how do we move away from merely collecting qualifications (trophies) to developing meaningful careers? Pharmacists in all areas and at all levels of the profession need to consider their own willingness to make this shift. The RPS and MPC are leading the way, but are we following?

The employee satisfaction -performance link: A unit -level analysis

In this dissertation, I present an integrated model of organizational performance. Most prior research has relied extensively on testing individual linkages, often with cross-sectional data. In this dissertation, longitudinal unit-level data from 559 restaurants, collected over a one-year period, were used to test the proposed model. The model was hypothesized to begin with employee satisfaction as a key antecedent that would ultimately lead to improved financial performance. Several variables including turnover, efficiency, and guest satisfaction are proposed as mediators of the satisfaction-performance relationship. The current findings replicate and extend past research using individual-level data. The overall model adequately explained the data, but was significantly improved with an additional link from employee satisfaction to efficiency, which was not originally hypothesized. Management turnover was a strong predictor of hourly level team turnover, and both were significant predictors of efficiency. Full findings for each hypothesis are presented and practical organizational implications are given. Limitations and recommendations for future research are provided. ^

RNA Virus Evolution: a Cross-scale, Disease Dynamic Perspective

RNA viruses are an important cause of global morbidity and mortality. The rapid evolutionary rates of RNA virus pathogens, caused by high replication rates and error-prone polymerases, can make the pathogens difficult to control. RNA viruses can undergo immune escape within their hosts and develop resistance to the treatment and vaccines we design to fight them. Understanding the spread and evolution of RNA pathogens is essential for reducing human suffering. In this dissertation, I make use of the rapid evolutionary rate of viral pathogens to answer several questions about how RNA viruses spread and evolve. To address each of the questions, I link mathematical techniques for modeling viral population dynamics with phylogenetic and coalescent techniques for analyzing and modeling viral genetic sequences and evolution. The first project uses multi-scale mechanistic modeling to show that decreases in viral substitution rates over the course of an acute infection, combined with the timing of infectious hosts transmitting new infections to susceptible individuals, can account for discrepancies in viral substitution rates in different host populations. The second project combines coalescent models with within-host mathematical models to identify driving evolutionary forces in chronic hepatitis C virus infection. The third project compares the effects of intrinsic and extrinsic viral transmission rate variation on viral phylogenies.

The association between parental attitudes and alcohol consumption and adolescent alcohol consumption in Southern Ireland: a cross-sectional study

Background: Alcohol plays a complex role in society. A recent study showed that over half of Irish adults drink hazardously. Adolescents report increased levels of alcohol consumption. Previous research has inferred the influence of the parent on their adolescent. Thus, the aim of the current study was to investigate the association between adolescent alcohol consumption and their parent’s consumption pattern and attitude toward alcohol use in Southern Ireland. Methods: A cross-sectional survey was undertaken in November 2014. This involved distributing a survey to adolescents (n = 982) in their final two years of second level education and at least one of their parents from a local electorate area in Southern Ireland. This survey included: alcohol use, self- reported height and weight, smoking status, mental health and well-being along with attitudinal questions. Chi-square tests and multivariate logistic regression were utilised. Results: A 37 % response rate was achieved. Over one-third (34.2 %) of adolescents and 47 % of parents surveyed reported hazardous drinking. Over 90 % of parents disagreed with allowing their adolescent to get drunk and rejected the idea that getting drunk is part of having fun as an adolescent. The majority (79.5 %) of parents surveyed believed that their alcohol consumption pattern set a good example for their adolescent. Multivariate logistic regression highlights the association between adolescent hazardous alcohol consumption and hazardous drinking by the father. Furthermore either parent permitting their adolescent to drink alcohol on special occasions was associated with hazardous alcohol consumption in the adolescent. Conclusion: The findings of this research notes a liberal attitude to alcohol and increased levels of consumption by the parent are linked to hazardous adolescent drinking behaviour. Future action plans aimed at combatting adolescent hazardous alcohol consumption should also be aimed at tackling parents’ attitudes towards and consumption of alcohol.

E-RUN version 1.1: Observational gridded runoff estimates for Europe, link to data in NetCDF format (69 MB)

River runoff is an essential climate variable as it is directly linked to the terrestrial water balance and controls a wide range of climatological and ecological processes. Despite its scientific and societal importance, there are to date no pan-European observation-based runoff estimates available. Here we employ a recently developed methodology to estimate monthly runoff rates on regular spatial grid in Europe. For this we first assemble an unprecedented collection of river flow observations, combining information from three distinct data bases. Observed monthly runoff rates are first tested for homogeneity and then related to gridded atmospheric variables (E-OBS version 12) using machine learning. The resulting statistical model is then used to estimate monthly runoff rates (December 1950 - December 2015) on a 0.5° x 0.5° grid. The performance of the newly derived runoff estimates is assessed in terms of cross validation. The paper closes with example applications, illustrating the potential of the new runoff estimates for climatological assessments and drought monitoring.

E-RUN version 1.0: Observational gridded runoff estimates for Europe, link to data in NetCDF format (68 MB)

River runoff is an essential climate variable as it is directly linked to the terrestrial water balance and controls a wide range of climatological and ecological processes. Despite its scientific and societal importance, there are to date no pan-European observation-based runoff estimates available. Here we employ a recently developed methodology to estimate monthly runoff rates on regular spatial grid in Europe. For this we first collect an unprecedented collection of river flow observations, combining information from three distinct data bases. Observed monthly runoff rates are first tested for homogeneity and then related to gridded atmospheric variables (E-OBS version 11) using machine learning. The resulting statistical model is then used to estimate monthly runoff rates (December 1950-December 2014) on a 0.5° × 0.5° grid. The performance of the newly derived runoff estimates is assessed in terms of cross validation. The paper closes with example applications, illustrating the potential of the new runoff estimates for climatological assessments and drought monitoring.

A suite of global, cross-scale topographic variables for environmental and biodiversity modeling, links to files in GeoTIFF format

Topographic variation, the spatial variation in elevation and terrain features, underpins a myriad of patterns and processes in geography and ecology and is key to understanding the variation of life on the planet. The characterization of this variation is scale-dependent, i.e. it varies with the distance over which features are assessed and with the spatial grain (grid cell resolution) of analysis. A fully standardized and global multivariate product of different terrain features has the potential to support many large-scale basic research and analytical applications, however to date, such technique is unavailable. Here we used the digital elevation model products of global 250 m GMTED and near-global 90 m SRTM to derive a suite of topographic variables: elevation, slope, aspect, eastness, northness, roughness, terrain roughness index, topographic position index, vector ruggedness measure, profile and tangential curvature, and 10 geomorphological landform classes. We aggregated each variable to 1, 5, 10, 50 and 100 km spatial grains using several aggregation approaches (median, average, minimum, maximum, standard deviation, percent cover, count, majority, Shannon Index, entropy, uniformity). While a global cross-correlation underlines the high similarity of many variables, a more detailed view in four mountain regions reveals local differences, as well as scale variations in the aggregated variables at different spatial grains. All newly-developed variables are available for download at http://www.earthenv.org and can serve as a basis for standardized hydrological, environmental and biodiversity modeling at a global extent.

Correlates of Vitamin D Status in Healthy Older Adults Living in Miami-Dade and its Association with Non-Skeletal Outcomes: A Cross-Sectional Study

Examining factors that affect vitamin D status in the fast-growing elderly population of Miami-Dade, Florida, is needed. Vitamin D deficiency in older adults has been linked to correlates of disability, including falls and fractures, and cardiovascular disease. The purpose of this study was to determine the proportion of vitamin D insufficient individuals and their relationship with vitamin D insufficiency in older adults (n=97) living in Miami-Dade. We evaluated the association between vitamin D status and 1) dual task physical performance to understand the link between vitamin D and cognition in the context of mobility; and 2) cardiometabolic risk, measured by galvanic skin response, pulse oximetry, and blood pressure to create a composite score based on autonomic nervous system and endothelial function. Participants completed baseline assessments that included serum levels of vitamin D, anthropometrics, body composition, dual task physical performance and cardiometabolic risk. Surveys to evaluate vitamin D intake, sun exposure, physical activity, and depressive symptoms were completed. Spearman’s correlations, independent t-tests, paired t-tests, repeated measures ANOVAs, and multiple logistic and linear regressions were used to examine the relationship of vitamin D insufficiency (25(OH)D /ml) and sufficiency (25(OH)D ≥30 ng/ml) with determinants of vitamin D status, dual task physical performance variables and cardiometabolic risk scores. Although the proportion of vitamin D insufficient individuals was lower when compared to the prevalance of the general United States elderly population, it was still common in healthy community-dwelling older adults living in Miami-Dade County, especially among Hispanics. Factors that affected skin synthesis (ethnicity, and sun exposure), and bioavailability/metabolism (obesity) were significant predictors of vitamin D status. Vitamin D insufficiency was not significantly correlated with worse dual task physical performance; however, cognitive performance was worse in the vitamin D insufficient group. Our results suggest a relationship of vitamin D insufficiency with executive dysfunction, and support an association with cardiometabolic risk using an innovative electro-sensor complex, possibly by modulating autonomic nervous system activity and vascular function, thus affecting cardiac performance.