Extreme events and event size fluctuations in biased random walks on networks

Random walk on discrete lattice models is important to understand various types of transport processes. The extreme events, defined as exceedences of the flux of walkers above a prescribed threshold, have been studied recently in the context of complex networks. This was motivated by the occurrence of rare events such as traffic jams, floods, and power black-outs which take place on networks. In this work, we study extreme events in a generalized random walk model in which the walk is preferentially biased by the network topology. The walkers preferentially choose to hop toward the hubs or small degree nodes. In this setting, we show that extremely large fluctuations in event-sizes are possible on small degree nodes when the walkers are biased toward the hubs. In particular, we obtain the distribution of event-sizes on the network. Further, the probability for the occurrence of extreme events on any node in the network depends on its 'generalized strength', a measure of the ability of a node to attract walkers. The 'generalized strength' is a function of the degree of the node and that of its nearest neighbors. We obtain analytical and simulation results for the probability of occurrence of extreme events on the nodes of a network using a generalized random walk model. The result reveals that the nodes with a larger value of 'generalized strength', on average, display lower probability for the occurrence of extreme events compared to the nodes with lower values of 'generalized strength'

On Performance of Integrated Satellite HAPS Ground Communication: Aerial IRS Node vs Terrestrial IRS Node

With a motive of ubiquitous connectivity over the globe with enhanced spectral efficiency, intelligent reflecting surfaces (IRS) integrated satellite-terrestrial communications is a topic of research interest in an infrastructure-deficient remote terrains. In line with this vision, this paper entails the performance analysis of satellite-terrestrial networks leveraging both aerial and terrestrial IRS nodes, with the support of high altitude platforms over diverse fading channels including shadowed Rician, Rician, and Nakagami-$m$ fading channels. The merits of IRS in enhancing spectral efficiency is analyzed through closed-form expressions of outage probability and ergodic rate. Further, the average symbol error rate analysis for the higher-order quadrature amplitude modulation (QAM) schemes such as hexagonal QAM, rectangular QAM, cross QAM, and square QAM is performed. Practical constraints like antenna gains, path loss, and link fading are considered to characterize the satellite terrestrial links. Finally, a comparison between the high-altitude platforms based IRS node and terrestrial IRS nodes is performed and various insights are drawn under various fading scenarios and path loss conditions. This paper contribute towards understanding and potential implementation of IRS-integrated satellite-terrestrial networks for efficient and reliable communication

Dosimetric impact of Acuros XB on cervix radiotherapy using RapidArc technique: a dosimetric study

BACKGROUND: Acuros XB (AXB) may predict better rectal toxicities and treatment outcomes in cervix carcinoma. The aim of the study was to quantify the potential impact of AXB computations on the cervix radiotherapy using the RapidArc (RA) technique as compared to anisotropic analytical algorithm (AAA) computations. MATERIALS AND METHODS: A cohort of 30 patients previously cared for cervix carcinoma (stages II–IIIB) was selected for the present analysis. The RA plans were computed using AAA and AXB dose computation engines under identical beam setup and MLC pattern. RESULTS: There was no significant (p > 0.05) difference in D95% and D98% to the planning target volume (PTV); moreover, a significant (p < 0.05) rise was noticed for mean dose to the PTV (0.26%), D50% (0.26%), D2% (0.80%) and V110% (44.24%) for AXB computation as compared to AAA computations. Further, AXB estimated a significantly (p < 0.05) lower value for maximum and minimum dose to the PTV. Additionally, there was a significant (p < 0.05) reduction observed in mean dose to organs at risk (OARs) for AXB computation as compared to AAA, though the reduction in mean dose was non-significant (p > 0.05) for the rectum. The maximum difference observed was 4.78% for the rectum V50Gy, 1.72%, 1.15% in mean dose and 2.22%, 1.48% in D2% of the left femur and right femur, respectively, between AAA and AXB dose estimations. CONCLUSION: For similar target coverage, there were significant differences observed between the AAA and AXB computations. AAA underestimates the V50Gy of the rectum and overestimates the mean dose and D2% for femoral heads as compared to AXB. Therefore, the use of AXB in the case of cervix carcinoma may predict better rectal toxicities and treatment outcomes in cervix carcinoma using the RA technique

Order and information in the patterns of spinning magnetic micro-disks at the air-water interface.

The application of the Shannon entropy to study the relationship between information and structures has yielded insights into molecular and material systems. However, the difficulty in directly observing and manipulating atoms and molecules hampers the ability of these systems to serve as model systems for further exploring the links between information and structures. Here, we use, as a model experimental system, hundreds of spinning magnetic micro-disks self-organizing at the air-water interface to generate various spatiotemporal patterns with varying degrees of order. Using the neighbor distance as the information-bearing variable, we demonstrate the links among information, structure, and interactions. We establish a direct link between information and structure without using explicit knowledge of interactions. Last, we show that the Shannon entropy by neighbor distances is a powerful observable in characterizing structural changes. Our findings are relevant for analyzing natural self-organizing systems and for designing collective robots

Low earth orbit satellite communications and services studies

The research grant was essentially for the development of datal communication terminals for LEO satellite systems. The services provided by LEO satellite systems are a variety. In this R&D work we have paid attention to services related to data acquisition from the ground or/and from the 0ceans.A particular service that we have focused relates to the oceanographic data collection. This data acquisition will support the characterization of the maritime environment in terms of salinity, temperature at various depths across the oceans in the world. Currently this service is referreed to as Array for Real-time Geostrophic Oceanography (ARGO). This ARGO system is supported by a number of international maritime organizations and countries. There are limitations on the present service and the R&D work initiated here is in collaboration with Institute of Telecommunication Research (ITR) Australia to extend the capability of the present ARGO system. This report essentially contains the design description and considerations for various hardware developed by ITR

To Evaluate the causes of Bleeding per Vagina in first Trimester of Pregnancy by Ultrasonography

Background &Method: This prospective study was done in the Department of Radiodiagnosis & Obstetrics and Gynaecology of Mahatma Gandhi Medical College & M.Y. Hospital, Indore, Madhya Pradesh, India after getting approval by ISRB (Institutional Scientific Review Board).A total of 100 patients who were referred to our department with clinical history of positive urine pregnancy test and vaginal bleeding during first trimester of pregnancy from April 2019 to October 2020 after written consent and PCPNDT registration were assessed. Various causes of vaginal bleeding confirmed by transabdominal and transvaginal ultrasound and beta human chorionic gonadotropin testing aid was done.Result:Age ranged from 18 to 35 years which show that most of the patients belongs to age group of 21 to 25 years making 42%. 31(31%) patients belongs to 26 to 30 years, 15(15%) patients to 17 to 20 years and the least common age group was between 31 to 35 years constituting 12(12%) patients. The mean age group is 24.00 (SD= 3.16).On the basis of clinical diagnosis in patients with bleeding per vaginum during first trimester of pregnancy maximum 40(40%) patients were diagnosed as threatened abortion, while 17(17%) patients as incomplete abortion , 13(13%) patients as missed abortion , 11(11%) patients as complete abortion , 7(7%) patients as inevitable abortion, 6(6%) patients as molar pregnancy, 6(6%) patients as ectopic pregnancy.the study of 95 patients with intrauterine pregnancy showing G-sac in 62(65.26%) cases and was absent in 33(34.74%) cases. 44(46.31%) shows yolk sac and were absent in 51(53.68%). CRL was found 38(40%) and were absent in 57(60%). Cardiac activity was seen in 9(9.48%) patients and 86(90.52%) patients had absent cardiac activity.Conclusion:Vaginal bleeding in the first trimester of pregnancy is a common obstetric problem. Ultrasound has become a valuable aid in the diagnosis and prognosis of various causes of bleeding per vaginum in first trimester of pregnancy. Ultrasound positively helps in accessing the continuation of pregnancy, timely intervention for abnormal pregnancy and avoiding unnecessary intervention in those cases who do not need them. In the above study it was demonstrated that it played an important part in diagnosing the causes of vaginal bleeding during first trimester of pregnancy

Modelling and simulation for high speed optical fiber receiver performance analysis

This report describes a model suitable for simulation of optical fiber communication system for transmission of digital data. The model is based on the idea of defining the spectral function for each of the sub-system like transmitter, fiber and receiver.RP 18/8

Do socio-demographic factors still predict the choice of place of delivery: A cross-sectional study in rural North India

Improving maternal health is one of the goals to be achieved under the Millennium Development Goal (MDG), especially MDG-5. One of the predictors of maternal health is place of child birth. This study was carried out to determine the prevalence of home delivery and different socio-demographic factors associated with them. This study was a community-based cross-sectional study. Women who delivered a baby in the past 1 year were included in this study. A total of 300 women responded (93.2%) and gave consent to participate in the study. Prevalence of home delivery was 37.7%. Bivariate analysis showed that religion, caste, education of women and their partners, occupation of the spouse, monthly family income and socioeconomic status had a significant association with the choice of place of delivery. But multivariate regression analysis showed only religion, caste, education of spouse and monthly income to be significant factors in determining place of delivery. The findings of this study suggest that individual countries have to formulate interventions which will target marginalized or vulnerable populations with reference to caste, religion and wealth. A significant improvement in reaching the 5th MDG can be achieved if the first three MDG goals are focused on, i.e., eradication of poverty, achieving universal education and women empowerment