Search results for "rection"
showing 10 items of 965 documents
ARQ Aware Scheduling for the IEEE 802.16 Base Station
2008
The IEEE 802.16 technology defines the ARQ mechanism that enables a connection to resend data at the MAC level if an error is detected. In this paper, we analyze the ARQ aware scheduling for the 802.16 base station. In particular, we consider how the BS scheduler can account for the ARQ block size, absence of the ARQ block rearrangement, and the ARQ transmission window. We propose a set of constraints that can be applied to any base station scheduler algorithm. To test them, we run a number of simulation scenarios. The simulations results confirm that the ARQ aware scheduling can improve the overall performance.
Performance analysis of the ieee 802.16 arq mechanism
2007
The IEEE 802.16 technology defines the ARQ mechanism that enables a connection to resend data at the MAC level if an error is detected. In this paper, we analyze the key features and parameters of the 802.16 ARQ mechanism. In particular, we consider a choice for the ARQ feedback type, an algorithm to build block sequences, a scheduling of the ARQ feedbacks and retransmissions, the ARQ block rearrangement, ARQ transmission window and ARQ block size. We run a number of simulation scenarios to study these parameters and how they impact a performance of application protocols. The simulation results reveal that the ARQ mechanism and its correct configuration play an important role in transmittin…
On ARQ feedback intensity of the IEEE 802.16 ARQ mechanism
2008
The IEEE 802.16 standard defines the ARQ mechanism as a part of the MAC layer. The functioning of the ARQ mechanism depends on a number of parameters. The IEEE 802.16 specification defines them but it does not provide concrete values and solutions. We ran simulation scenarios to study how the ARQ feedback intensity impacts the performance of application protocols. The simulation results reveal that a low ARQ feedback intensity results only in a marginal improvement. Though it is possible to optimize the ARQ feedback intensity, it is reasonable to rely upon more frequent ARQ feedback messages as they do not result in a performance degradation. At the same time, ARQ connections, which work on…
Testing for Government Intertemporal Solvency: A Smooth Transition Error Correction Model Approach
2001
Applied macroeconomists have tested for the government intertemporal solvency condition by either testing for linear stationarity in the total government deficit series or testing for linear cointegration between total government spending and total tax revenues. A number of authors have focused, in particular, on structural breaks in the government deficit process. In this paper, we use a smooth transition error correction model to test and estimate a shift in the adjustment toward a linear cointegration relationship between the government spending to output ratio and the total tax revenues to output ratio. Estimation results show that government authorities react only to large (in absolute…
Assessing eco-efficiency: A metafrontier directional distance function approach using life cycle analysis
2017
Sustainability analysis requires a joint assessment of environmental, social and economic aspects of production processes. Here we propose the use of Life Cycle Analysis (LCA), a metafrontier (MF) directional distance function (DDF) approach, and Data Envelopment Analysis (DEA), to assess technological and managerial differences in eco-efficiency between production systems. We use LCA to compute six environmental and health impacts associated with the production processes of nearly 200 Spanish citrus farms belonging to organic and conventional farming systems. DEA is then employed to obtain joint economic-environmental farm's scores that we refer to as eco-efficiency. DDF allows us to deter…
A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo
2021
This paper presents the gravitational-wave measurement of the Hubble constant (H 0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H 0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H 0 = km s-1 Mpc-1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 (about 4%) over the GW170817-only value of km s-1 Mpc-1. A significant …
POSSIBILITIES OF THE HEALTH CARE PERFECTION IN LATVIA
2010
Characterizing the health care system from the sustainable point of view, it is important to evaluate the operational principles of the healthy society. It is necessary to evaluate the existing problems in the health care sector and to identify further development possibilities in order to be able to perform the high healthy society standard. The Latvian financial accessibility of the health care during the last years has been explored. The article provides the analysis of main development tendencies of the medical accessibility for inhabitants, where suggestions of potentialities for their further development are given.
Halogen bond directionality translates tecton geometry into self-assembled architecture geometry
2013
The structures of halogen-bonded infinite chains involving two diiodoperfluoroalkanes and a bent bis(pyrid-4′-yl)oxadiazole show that the geometry of the pyridyl pendant rings is translated into the angle between the formed halogen bonds.
A First-Principles Study of the Ag/a-Al2O3(0001) Interface
2001
Ab initio simulations of the Ag/a-Al2O3(0001) interface have been performed for periodic slab models. We have considered Al- and O-terminated corundum surfaces, low and high substrate coverages by silver, as well as the two preferred Ag adsorption sites. The two different terminations give rise to qualitatively different results: silver physisorption on the Al-terminated substrate and chemisorption on O-terminated one. The latter could be treated as a possible model for the defective Al-terminated substrate, where the outermost aluminium ions are removed (completely or partly). This makes O-terminated surface highly reactive towards a deposited metal, in order to restore initial corundum st…
Understanding frailty:a qualitative study of European healthcare policy-makers' approaches to frailty screening and management
2018
ObjectiveTo elicit European healthcare policy-makers’ views, understanding and attitudes about the implementation of frailty screening and management strategies and responses to stakeholders’ views.DesignThematic analysis of semistructured qualitative interviews.SettingEuropean healthcare policy departments.ParticipantsSeven European healthcare policy-makers representing the European Union (n=2), UK (n=2), Italy (n=1), Spain (n=1) and Poland (n=1). Participants were sourced through professional networks and the European Commission Authentication Service website and were required to be in an active healthcare policy or decision-making role.ResultsSeven themes were identified. Our findings re…