Search results

The purpose of this paper is to present the problem of implementation of the differential global navigation satellite system (DGNSS) differential technique for aircraft accuracy positioning. The paper particularly focuses on identification and an analysis of the accuracy of aircraft positioning for the DGNSS measuring technique.

The investigation uses the DGNSS method of positioning, which is based on using the model of single code differences for global navigation satellite system (GNSS) observations. In the research experiment, the authors used single-frequency code observations in the global positioning system (GPS)/global navigation satellite system (GLONASS) system from the on-board receiver Topcon HiperPro and the reference station REF1 (reference station for the airport military EPDE in Deblin in south-eastern Poland). The geodetic Topcon HiperPro receiver was installed in Cessna 172 plane in the aviation test. The paper presents the new methodology in the DGNSS solution in air navigation. The aircraft position was estimated using a “weighted mean” scheme for differential global positioning system and differential global navigation satellite system solution, respectively. The final resultant position of aircraft was compared with precise real-time kinematic – on the fly solution.

In the investigations it was specified that the average accuracy of positioning the aircraft Cessna 172 in the geocentric coordinates XYZ equals approximately: +0.03 ÷ +0.33 m along the x-axis, −0.02 ÷ +0.14 m along the y-axis and approximately +0.02 ÷ −0.15 m along the z-axis. Moreover, the root mean square errors determining the measure of the accuracy of positioning of the Cessna 172 for the DGNSS differential technique in the geocentric coordinates XYZ, are below 1.2 m.

In research, the data from GNSS onboard receiver and also GNSS reference receiver are needed. In addition, the pseudo-range corrections from the base stations were applied in the observation model of the DGNSS solution.

The presented research method can be used in a ground based augmentation system (GBAS) augmentation system, whereas the GBAS system is still not applied in Polish aviation.

The paper is destined for people who work in the area of aviation and air transport.

The study presents the DGNSS differential technique as a precise method for recovery of aircraft position in civil aviation and this method can be also used in the positioning of aircraft based on GPS and GLONASS code observations.

This study aims to address the issue of prediction of inflation differences for an economy that considers either fixing its exchange rate or joining a currency union. In this setting, individual countries have limited control over their inflation, and anticipating the possible course of domestic inflation relative to inflation abroad becomes an important input in policy-making. In this context, the author compares simple forecast heuristics and econometric modeling.

The study compares two basically different approaches. The first approach of forecasting consists of simple heuristics. Various heuristics are considered that differ with respect to the economic reasoning that goes into quantifying the forecast rules. The simplest such forecasting heuristic suggests that the average over all available observations of inflation differentials should be taken as a predictor for the future. Bringing more economic insight to bear suggests a further heuristic according to which historical inflation differentials should be adjusted for changes in the nominal exchange rate. A further variant of this approach suggests that a forecast should exclusively rely on data from earlier times under a pegged exchange rate. A fundamentally different approach to prediction builds on dynamic econometric models estimated by using all available historical data independent of the currency regime.

The author studies three small member countries of the Eurozone, i.e. Finland, Luxembourg and Portugal. For the evaluation of the various forecasting strategies, he performs out-of-sample predictions over a horizon of five years. The comparison of the four different forecasting strategies documents that the variant of the forecast heuristic that draws on data from earlier experiences under fixed exchange rates performs better than the forecast based on the estimated econometric model.

The findings of this study provide helpful guidelines for countries considering either joining a currency union or fixing their exchange rate. The author shows that a simple forecasting heuristic gives sound advice for assessing the likely course of inflation.

This study describes how economic theory can guide the selection of historical data for assessing likely future developments. The analysis shows that using a simple heuristic based on historical analogy can lead to better forecasts than the analytically more sophisticated approach of econometric modeling.

The aim of this paper is to explore mindfulness and self-compassion teachings and practices embedded in a leadership course and their outcome on stress regulation of doctoral-level students.

Eight valid and reliable pre-and post-assessment inventories were administered prior to the first week of class and following the completion of the doctoral-level class. The test scores were measured for improvement and for differences between various demographic groups.

The results suggest significant improvement on almost every mindfulness subscale with approximately 5–22% of the variance in subscale scores attributed to participation. Doctoral students over 40 indicated more score improvement than students under 40, and doctoral students of color indicated more significant score increases than White students.

The research involves doctoral-level students which limits generalizability to other levels of education. Based on the findings, scaling analysis should be conducted on other types of students for generalization purposes.

Institutions looking to incorporate wellness practices into curriculum can embed these types of practices into their course design.

Faculty can become more intentional in how they engage students in mindful compassion skills within their academic programs.

The paper adds a quantitative study into the literature surrounding efficacy of wellness practices in structured curriculum. Institutions looking to provide more resources to students to improve their wellness may find the model useful on their campuses, particularly for students over 40 and students of color.

Identifies some managerially relevant factors that influence the size of the price premium that consumers will pay for national brands over store brands in grocery products. We define price premium as the maximum price consumers will pay for a national brand over a store brand, expressed as the proportionate price differential between a national brand and a store brand. Overall, perceived quality differential accounts for about 12 percent of the variation in price premiums across consumers and product categories and is the most important variable influencing price premiums.

Retailer internationalisation (RI) is lacking in detailed empirical research. What is available ignores the critical factors important to the success of retailers operating internationally. Consequently, this exploratory study attempts to unearth various factors, labelled Differential Firm Advantages (DFA), vital to the smooth performance and competitive differentiation of international retail operations. The nature and attributes of DFAs, with specific reference to retailing, are reviewed and subsequent survey results reveal certain DFAs can be regarded as prerequisites for retailers operating in international markets. The underlying structure of differential advantages is also examined, giving the study a further unique dimension. Performance in international markets appears to depend upon the balanced integration of various compatible DFAs. Indeed past experiences show certain UK‐based international retailers have had problems in achieving this equilibrium.

The purpose of this paper is to show that for some key topics on labour economics such as the effect of seniority and job mobility in wages, it is important to explicitly consider firm fixed effects. The author also wants to test whether the importance of firm in explaining wage dispersion is higher or lower in Spain than in other European countries.

The author estimates an individual wage equation where firm and workers effects are considered and the estimation process control for censored wages. This exercise is performed for the Spanish economy over the course of a whole business cycle, i.e., 2000-2015.

The author demonstrates that Spanish firms contribute to explain around 27 per cent of the individual wage heterogeneity but more importantly around 74 per cent of inter-industry wage differentials. In both cases, this contribution is mainly related to large dispersion in firm’s wage policies. The process of positive sorting of workers across firms or industries does not play an important role. Interestingly, the importance of firm’s wage policies in explaining individual wage dispersion has increased over the current Big Recession.

The results confirm that firms set wages and, henceforth, are partially responsible for individual wage heterogeneity but more importantly for inter-industrial wage dispersion.

The exercise is performed under optimal conditions because the author uses a longitudinal matched employer-employee data set, observed wages are at a monthly frequency, and implements an estimation method suitable for censored models with two high-dimensional fixed effects. This is the first study that looks deeply into the role of firms in explaining wage heterogeneity at the individual and industry level in Spain and along the current Big Recession.

Building on the concept of “impact literacy” established in a previous paper from Bayley and Phipps, here we extend the principles of impact literacy in light of further insights into sector practice. More specifically, we focus on three additions needed in response to the sector-wide growth of impact: (1) differential levels of impact literacy; (2) institutional impact literacy and environment for impact; and (3) issues of ethics and values in research impact. This paper invites the sector to consider the relevance of all dimensions in establishing, maintaining and strengthening impact within the research landscape. We explore implications for individual professional development, institutional capacity building and ethical collaboration to maximise societal benefit.

This article aims to add to the growing number of critical empirical studies and to reflect on the process of conducting this type of research, thereby addressing the lack of exemplars for those engaged with critical empirical information systems research.

Applies the critical lens to a multi‐year examination of variation in the career narratives of women in the American IT labor force. While an interpretive epistemology was initially chosen for this research project, over time, analysis of interview data took on an increasingly critical orientation. This, in turn, influenced subsequent fieldwork to become critical in nature.

One theoretical contribution is highlighting the role of power dynamics in understanding what sits beneath the surface of observations about these women's experiences in the IT workforce. The second theoretical contribution is helping to shift the focus away from predominantly essentialist theories that dichotomize men and women and toward a recognition of the diversity among women in the IT field.

Future research should include additional critical empirical studies of women in the IT field in other countries.

This research project can serve as a useful example for other critical IS researchers about to embark on empirical fieldwork.

This paper provides a concrete illustration of the way in which empirical research is altered as the epistemological lens shifts from interpretivist to critical.

The purpose of this paper is to examine the comparative abilities of current period cash flows and earnings (and its components) to predict one‐year‐ahead cash flow from operations in Egypt.

The study uses the cash flow prediction models developed by Barth, Cram, and Nelson to examine the predictive abilities of earnings and cash flows for future cash flows. The first set of prediction models uses cross‐sectional regression to compare the predictive abilities of cash flows and aggregate earnings for one‐year‐ahead cash flow from operations. The second set of prediction models tests whether disaggregating earnings into cash flows and the major components of accruals enhances the predictive ability of earnings for one‐year‐ahead cash flow from operations.

The findings of the study reveal that aggregate earnings have superior predictive ability than cash flows for future cash flows. Also, the results reveal that disaggregating accruals into major components – changes in accounts receivable and payable, and in inventory, depreciation, amortization, and other accruals – significantly enhances predictive ability of earnings.

The study provides empirical evidence on the superiority of earnings in predicting future cash flows. The findings of the study should be considered in explaining the results of value relevance research Egypt. However, owing to relatively small sample size, given the thinness of the Egyptian capital market, these findings should be interpreted with caution.

The paper contributes to the limited body of research on the superiority of earnings and cash flows in predicting future cash flows by examining the predictive abilities of earnings and cash flows for future cash flows in Egypt as one of many emerging markets.

The number of university students exhibiting mental health concerns have surged considerably in the past decade. Amongst a number of potential contributing factors, this study aims to assess the role of a broader societal phenomenon; the shift in emphasis in our interactions from the physical to the virtual environments. Specifically, a decrease in nature contact and a contrasting increase in smartphone use are identified as two pathways in which this shift may impact negatively on mental health. Previous research evidences both facets as consistent correlates of depression, although limited research extends these associations to the student population or attempts to establish an interaction between the two.

The current study recruited a sample of 380 first-year undergraduate students, via an online survey, to assess if problematic smartphone use (SAS-SV) and nature contact (NCQ) were significant predictors of depression (PHQ-9).

Nature contact frequency and smartphone use were significant predictors of depression.

This is the first study to concurrently assess the impact of smartphone use and nature contact in a student population.