On the Monotonicity of the Generalized Marcum and Nuttall Q-Functions

Monotonicity criteria are established for the generalized Marcum Q-function, \emph{Q}_{M}, the standard Nuttall Q-function, \emph{Q}_{M,N}, and the normalized Nuttall Q-function, $\mathcal{Q}_{M,N}$, with respect to their real order indices M,N. Besides, closed-form expressions are derived for the computation of the standard and normalized Nuttall Q-functions for the case when M,N are odd multiples of 0.5 and $M\geq N$. By exploiting these results, novel upper and lower bounds for \emph{Q}_{M,N} and $\mathcal{Q}_{M,N}$ are proposed. Furthermore, specific tight upper and lower bounds for \emph{Q}_{M}, previously reported in the literature, are extended for real values of M. The offered theoretical results can be efficiently applied in the study of digital communications over fading channels, in the information-theoretic analysis of multiple-input multiple-output systems and in the description of stochastic processes in probability theory, among others.Comment: Published in IEEE Transactions on Information Theory, August 2009. Only slight formatting modification

Geoid undulation computations at laser tracking stations

Geoid undulation computations were performed at 29 laser stations distributed around the world using a combination of terrestrial gravity data within a cap of radius 2 deg and a potential coefficient set up to 180 deg. The traditional methods of Stokes' and Meissl's modification together with the Molodenskii method and the modified Sjoberg method were applied. Performing numerical tests based on global error assumptions regarding the terrestrial data and the geopotential set it was concluded that the modified Sjoberg method is the most accurate and promising technique for geoid undulation computations. The numerical computations for the geoid undulations using all the four methods resulted in agreement with the ellipsoidal minus orthometric value of the undulations on the order of 60 cm or better for most of the laser stations in the eastern United States, Australia, Japan, Bermuda, and Europe. A systematic discrepancy of about 2 meters for most of the western United States stations was detected and verified by using two relatively independent data sets. For oceanic laser stations in the western Atlantic and Pacific oceans that have no terrestrial data available, the adjusted GEOS-3 and SEASAT altimeter data were used for the computation of the geoid undulation in a collocation method

Generation Z consumers\u27 expectations of interactions in smart retailing: A future agenda

© 2017 The Authors Retailing is witnessing a transformation due to rapid technological developments. Retailers are using smart technologies to improve consumer shopping experiences and to stay competitive. The biggest future challenge for marketing and consequently for retailing seems to be generation Z, since members of this generation seem to behave differently as consumers and are more focused on innovation. The aim of this paper is to explore Generation Z consumers\u27 current perceptions, expectations and recommendations in terms of their future interactions in smart retailing contexts. To do so, we used a qualitative approach by conducting a series of semi-structured in depth interviews with 38 university students-consumers in the UK market. The findings showed that smart technologies have a significant influence on generation Z consumers\u27 experiences. Moreover, this particular group of consumers expects various new devices and electronic processes to be widely available, thus offering consumers more autonomy and faster transactions. In addition, they expect the technology to enable them to make more informed shopping decisions. Interviewees also stressed the importance of training consumers how to use new smart retailing applications. In addition, some of the participants were sceptical about the effects of further advancing smart retailing on part of the job market. Relevant theoretical and practical implications are also provided

The effect of sport tourists\u27 travel style, destination and event choices, and motivation on their involvement in small-scale sports events

© 2018 Cognizant, LLC. This exploratory study investigates whether and in which way motivation and destination, travel, and event selection criteria influence sport tourists\u27 involvement in small-scale events. Thus, a model was developed and tested at a small-scale sport event in Sfendami, Greece. To test the six hypotheses of the proposed model a primary research study was conducted, which received responses from 181 participants. Implementation of the partial least square technique showed that changes in sport tourists\u27 travel style exert a direct and positive effect on involvement, as well as an indirect effect with motivation acting as a mediator; however, perception of destination and events characteristics does not exert a significant influence on participants\u27 involvement. Additionally, the model\u27s ability to predict the motivational aspects of sport tourists\u27 participation was demonstrated. Multidimensional scaling was employed to assist with event service design and improve organizers\u27 capabilities to develop effective promotional strategies

Potential Impact of the Financial Crisis on Outpatient Hospital Visits due to Otorhinolaryngologic Disorders in Crete, Greece

The public health effect of financial crises has been emphasized in previous studies. In addition, a series of otorhinolaryngologic disorders and manifestations has been related to psychological factors in the literature. Such conditions include temporomandibular joint disorders, laryngopharyngeal reflux, chronic tinnitus, and vertigo. Focusing on the outpatient database records of a large hospital in Crete, Greece, the objective of this retrospective study was to explore possible occurrence variations within the prementioned otorhinolaryngologic morbidity which may be potentially attributed to increased levels of socioeconomic stress. Results revealed that although the total number of visits between two periods - before and after the beginning of the financial crisis in Greece - was comparable, a significant increase in the diagnosis of two disorders, namely vertigo and tinnitus was found. In addition, a trend toward increased rate of diagnosis for reflux and temporomandibular joint disorders was noted. Potential implications of these findings are discussed. In conclusion, health care providers in this as well as in other countries facing similar socio-economic conditions should be aware of potential changes in the epidemiologic figures regarding specific medical conditions