Analytical Model of Proportional Fair Scheduling in Interference-limited OFDMA/LTE Networks

Various system tasks like interference coordination, handover decisions, admission control etc. in upcoming cellular networks require precise mid-term (spanning over a few seconds) performance models. Due to channel-dependent scheduling at the base station, these performance models are not simple to obtain. Furthermore, upcoming cellular systems will be interference-limited, hence, the way interference is modeled is crucial for the accuracy. In this paper we present an analytical model for the SINR distribution of the \textit{scheduled} subcarriers of an OFDMA system with proportional fair scheduling. The model takes the precise SINR distribution into account. We furthermore refine our model with respect to uniform modulation and coding, as applied in LTE networks. The derived models are validated by means of simulations. In additon, we show that our models are approximate estimators for the performance of rate-based proportional fair scheduling, while they outperform some simpler prediction models from related work significantly.Comment: 7 pages, 6 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Expression of the Periplaneta americana\u27s α-adrenergic-like octopamine receptor in the yeast Saccharomyces cerevisiae: A high-throughput screening system in search of biorational insecticides

The use of conventional synthetic insecticides is facing increased scrutiny due to environmental and mammalian health concerns along with resistance to target insects. This has led to an investigation of alternative control measures to combat both economically and medically important arthropods. Octopamine, a biogenic amine, has significant physiological functions in invertebrates, including insects, and signals through G-protein-coupled receptors (GPCRs). Co-evolution of plants with insects has led to plants adapting defensive mechanisms to deter herbivore, microbial, or viral attack. This is sometimes accomplished via the production of essential oils that are composed of a variety of compounds, in particular monoterpenoids, sesquiterpenoids and aromatic compounds. Here we report on the functional coupling of a ligand-independent α-adrenergic-like octopamine receptor from the American cockroach and its expression in the yeast, Saccharomyces cerevisiae. This expression system allows us to screen a large number of compounds to determine efficacy at this octopamine receptor. We have found many monoterpenoids, sesquiterpenoids and aromatic compounds from essential oils that interact with this octopamine receptor and may account for their insecticidal action in this insect

Botanical pesticides: identification of a molecular target and mode of action studies

Mosquitoes and ticks are vectors of several diseases that affect both humans and animals. Control of mosquito-borne and tick-borne diseases has primarily been achieved with the use of chemical insecticides/acaricides. However, an increase in public concern about the safety of conventional synthetic compounds, along with growing insecticide/acaricide resistance, has resulted in a need to find alternatives to control ticks and mosquitoes. In this dissertation I report on the functional and pharmacological characterization of a tyramine receptor from the southern cattle tick (Rhipicephalus microplus). Additionally, I report on the role of botanical essential oil terpenoids to interact with the southern cattle tick\u27s tyramine receptor. Physiological studies of the southern cattle tick\u27s tyramine receptor, using post-transcription gene silencing, show that the southern cattle tick\u27s tyramine receptor is a target that can result in tick mortality. The significance of these results is the reclassification of the southern cattle tick\u27s tyramine receptor (previously thought to be an octopamine receptor), the identification of a potentially novel target of plant terpenoids in the southern cattle tick and an explanation for the potential role of formamidine resistance, which has been reported in the southern cattle tick. Finally, I present the ability of essential oils to enhance the toxicity and/or knockdown of the synthetic pyrethroid permethrin, against two mosquito species (Aedes aegypti and Anopheles gambiae). The enhancement of toxicity and knockdown is similar to, but in many cases, better than the commercial synergist piperonyl butoxide (PBO). The significance of these findings includes the ability to use natural control measures to replace PBO, which has been under scrutiny for non-target toxicological issues

Design as exploring constraints

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHBibliography: leaves 139-143.by Mark Donald Gross.Ph.D

Mesial temporal sclerosis is linked with more widespread white matter changes in temporal lobe epilepsy

AbstractTemporal lobe epilepsy patients with unilateral mesial temporal sclerosis (TLE+uMTS) have been demonstrated to have extensive white matter abnormalities both ipsilateral and contralateral to the seizure onset zone. However, comparatively less is known about the white matter integrity of TLE patients without MTS (non-lesional TLE, nl-TLE). The purpose of the study was to investigate the diffusion properties of thirteen major white matter tracts in patients with TLE+uMTS and nl-TLE. Diffusion tensor imaging (DTI) was performed on 23 TLE+uMTS (15 left MTS and 8 right MTS), 15nl-TLE and 21 controls. Thirteen tracts were delineated by tractography and their diffusion parameters compared for the two TLE groups relative to controls, with left and right hemispheres combined per tract. A subgroup analysis investigated left and right MTS separately. Compared to controls, reduced anisotropy was detected in ten tracts for TLE+uMTS, but only the parahippocampal cingulum and tapetum for nl-TLE. Right MTS subgroup showed reduced anisotropy in 7 tracts bilaterally (3 limbic, 3 association, 1 projection) and 2 tracts ipsilaterally (1 association, 1 projection) and the body of the corpus callosum whereas the left MTS subgroup showed reduced anisotropy in 4 tracts bilaterally (2 limbic, 1 association, 1 projection) and 2 tracts ipsilaterally (1 limbic, 1 association). Diffusion abnormalities in tracts were observed within and beyond the temporal lobe in TLE+uMTS and were more widespread than in nl-TLE. Patients with right MTS had more extensive, bilateral abnormalities in comparison to left MTS. These findings suggest different dysfunctional networks in TLE patients with and without MTS

Compact group actions, spherical bessel functions, and invariant random variables

The theory of compact group actions on locally compact abelian groups provides a unifying theory under which different invariance conditions studied in several contexts by a number of statisticians are subsumed as special cases. For example, Schoenberg’s characterization of radially symmetric characteristic functions on Iw” is extended to this general context and the integral representations are expressed in terms of the generalized spherical Bessel functions of Gross and Kunze. These same Bessel functions are also used to obtain a variant of the Lkvy-Khinchine formula of Parthasarathy, Ranga Rao, and Varadhan appropriate to invariant distributions

An Innovative Interactive Modeling Tool to Analyze Scenario-Based Physician Workforce Supply and Demand

Effective physician workforce management requires that the various organizations comprising the House of Medicine be able to assess their current and future workforce supply. This information has direct relevance to funding of graduate medical education. We describe a dynamic modeling tool that examines how individual factors and practice variables can be used to measure and forecast the supply and demand for existing and new physician services. The system we describe, while built to analyze the pathologist workforce, is sufficiently broad and robust for use in any medical specialty. Our design provides a computer-based software model populated with data from surveys and best estimates by specialty experts about current and new activities in the scope of practice. The model describes the steps needed and data required for analysis of supply and demand. Our modeling tool allows educators and policy makers, in addition to physician specialty organizations, to assess how various factors may affect demand (and supply) of current and emerging services. Examples of factors evaluated include types of professional services (3 categories with 16 subcategories), service locations, elements related to the Patient Protection and Affordable Care Act, new technologies, aging population, and changing roles in capitated, value-based, and team-based systems of care. The model also helps identify where physicians in a given specialty will likely need to assume new roles, develop new expertise, and become more efficient in practice to accommodate new value-based payment model