Critical Scale for a Continuous AIMD Model

A scaled version of the general AIMD model of transmission control protocol (TCP) used in Internet traffic congestion management leads to a Markov process x(t) representing the time dependent data flow that moves forward with constant speed on the positive axis and jumps backward to γx(t), 0 < γ < 1 according to a Poisson clock whose rate α(x) depends on the interval swept in between jumps. We give sharp conditions for Harris recurrence and analyze the convergence to equilibrium on multiple scales (polynomial, fractional exponential, exponential) identifying the critical case xα(x) ～ β. Criticality has different behavior according to whether it occurs at the origin or infinity. In each case, we determine the transient (possibly explosive), null—and positive—recurrent regimes by comparing β to ( ? ln?γ)^{? 1}.     

Socio-Economic Disparities in the Development of the Romania’s Border Areas

The Romanian border areas include 898 Local Administrative Units 2 (LAU2), of which 88 are urban and 810 rural. Romania has borderline with the following countries: Bulgaria, Republic of Moldova, Serbia, Ukraine, Hungary, of which 63.5 % is Non-European Union boundary. According to the population structure, 51.6 % of the total population is urban and the rest of 48.4 % is rural. In order to assess the socio-economic territorial disparities in the development of the urban space of Romanian border areas, several research stages were carried out: selecting 22 relevant statistical indicators, analyzing territorial disparities, standardizing the absolute values of the indicators, grouping the elementary indicators by 7 multiple indicator clusters (secondary indexes) in order to reflect the main socio-economic development aspects: (1) housing, (2) public utilities infrastructure and green areas, (3) health, (4) labour market, (5) demography, (6) education and (7) local economy. Finally, the authors were able to compute secondary indexes and the Index of Socio-Economic Development as Hull Score with a mean of 50 and a standard deviation of 14, revealing the levels of socio-economic development (high, average and low). Generally, the outcomes of the current study are in line with Romania’s complex socio-economic disparities, rooted in the historic background of the country. Spatially, the economic development follows a West–East direction, the less developed areas being concentrated in the Eastern and Southern part of the country.     

Paper Versus Electronic Medical Records: The Effects of Access on Physicians' Decisions to Use Complex Information Technologies*

This study examines physicians' responses to complex information technologies (IT) in the health care supply chain. We extend individual‐level IT adoption models by incorporating a new construct: system accessibility. The main premise of the study is, when faced with a decision between alternate IT systems, individual users tend to select and make use of the technology or system that is most readily accessible. We discuss both physical and logical dimensions of accessibility as they relate to adoption of electronic medical records (EMR). Physical accessibility refers to the availability of computers that can be used to access EMR, while logical accessibility refers to the ease or difficulty of logging into the system. Using data from a survey of 199 physicians practicing in a large U.S. hospital, we show that, when deciding between the paper chart and EMR, accessibility is an important consideration in a physician's decision to use the system. Both dimensions of accessibility act as barriers to EMR use intentions through their indirect effect on physicians' perceptions of EMR usefulness and ease of use. Logical access also has a direct effect on EMR use intentions. We conclude that accessibility is an important factor that limits acceptance of complex IT such as EMR.