An improved medium access control protocol for real-time applications in WLANs and its firmware development

The IEEE 802.11 Wireless Local Area Network (WLAN), commonly known as Wi-Fi, has emerged as a popular internet access technology and researchers are continuously working on improvement of the quality of service (QoS) in WLAN by proposing new and efficient schemes. Voice and video over Internet Protocol (VVoIP) applications are becoming very popular in Wi-Fi enabled portable/handheld devices because of recent technological advancements and lower service costs. Different from normal voice and video streaming, these applications demand symmetric throughput for the upstream and downstream. Existing Wi-Fi standards are optimised for generic internet applications and fail to provide symmetric throughput due to traffic bottleneck at access points. Performance analysis and benchmarking is an integral part of WLAN research, and in the majority of the cases, this is done through computer simulation using popular network simulators such as Network Simulator ff 2 (NS-2) or OPNET. While computer simulation is an excellent approach for saving time and money, results generated from computer simulations do not always match practical observations. This is why, for proper assessment of the merits of a proposed system in WLAN, a trial on a practical hardware platform is highly recommended and is often a requirement. In this thesis work, with a view to address the abovementioned challenges for facilitating VoIP and VVoIP services over Wi-Fi, two key contributions are made: i) formulating a suitable medium access control (MAC) protocol to address symmetric traffic scenario and ii) firmware development of this newly devised MAC protocol for real WLAN hardware. The proposed solution shows signifocant improvements over existing standards by supporting higher number of stations with strict QoS criteria. The proposed hardware platform is available off-the-shelf in the market and is a cost effective way of generating and evaluating performance results on a hardware system

Study of seroprevalence of antibodies to SARS-COV-2 among the healthy blood donors of Jammu region

Background: SARS‑CoV‑2 emerged in China and spread throughout the world due to its rapid transmission. The exposure rate in the healthy population is unknown, mainly in resource‑limited countries. Herein, we estimated the seroprevalence of anti‑SARS‑CoV‑2 antibodies and risk factors among blood donors at our blood bank and to describe some characteristics of those that test positive. The objective of the study was to measure the levels of IgG antibodies targeting the SARS-CoV2 during the peak period of the COVID-19 pandemic in Jammu State, India to know the magnitude of SARS-CoV-2 exposure, the prevalence of herd immunity in the population.Methods: This is prospective observational study of COVID-19 seroprevalence among blood donors that complied with blood donation protocol. Participation in study was voluntary after taking proper consent on the consent form.Results: A total of 750 random blood donors who voluntarily participated, were enrolled in this study after obtaining their proper consent on the consent form. Out of 750 donors, 287 (38.2%) were positive for IgG antibodies and 463 (61.7%) were negative for IgG antibodies. In our study, male donors (745) outnumbered the female donors but on the other hand female donors showed a higher prevalence of covid antibodies i.e., 60% as compared to male donors i.e., 38% which is a statistically significant difference (p<0.005).Conclusions: A high prevalence of SARS-CoV-2 antibodies was detected among blood donors which indicated a high level of exposure to the virus within the population and development of innate immunity against the virus. This could help us to introduce a protocol of antibody testing in the screening of blood donors to enhance the number of plasma donation cases for the treatment of serious COVID patients

Impact of COVID-19 outbreak on the blood donation and utilization and strategies adopted to combat it in a tertiary care center of Jammu province

Background: The COVID-19 pandemic has major implications for blood transfusion. There are uncertain patterns of demand, and transfusion institutions need to plan for reductions in donations and loss of crucial staff because of sickness and public health restrictions. A range of strategies need to be planned to maintain ongoing equitable access to blood for transfusion during the pandemic, in addition to providing new therapies such as convalescent plasma. The main role of transfusion institutions during this period, is the monitoring of supply and demand so that sufficient blood stocks are maintained to support ongoing critical needs. The main aim of our study was to study the impact of COVID-19 outbreak on blood transfusion services (BTS) and to identify the challenges faced by our blood center and mitigation strategies adopted to combat it.Methods: Total number of donations and total number of blood and its components issued were noted from the donor and issue registers respectively, both during the pre-COVID and COVID-19 pandemic and the results were compared thereafter. Various strategies were adopted during the COVID pandemic in order to maintain balance between demand and supply of blood and its products.Results: There has been sudden decrease in the number of blood donations in the month of April 2020 (35%) in the COVID pandemic as compared to pre-COVID time with percentage difference of 65%. This was followed by gradual decrease in the no. of donations in COVID pandemic when compared with donations in the pre-COVID time. The percentage difference in blood donation gradually improved over a period of time from 65% in April 2020 to 7% in April 2021. Similarly, no. of blood units issued also decreased from 1147 in April 2019 to 553 units in April 2020.Conclusions: The BTS need to provide an uninterrupted blood supply, and this stays true even in the face of a pandemic. The plan of action has to be started early so that the supply can be maintained and monitored effectively. Health-care workers being one of the main pillars in the fight against COVID-19 have to be supported and protected.

Effectiveness of buffy coat leucoreduced packed red blood cells in decreasing febrile non-hemolytic transfusion reactions in thalassemic patients

Background: Blood transfusions have always been associated with a number of adverse outcomes which have steadily decreased over years owing to new discoveries and technical advancements. Thalassemic patients are more prone to transfusions related complications owing to repeated transfusions. Study of these reactions and correlating them with the leucodepletion status of the transfused packed red blood cells (PRBCs) reduces transfusion complications due to the transfused leukocytes.Methods: This is a prospective study carried out on 1750 transfusions in 138 thalassemic patients at our institute between August 2015 and March 2016. The total transfusions were classified into four categories depending on the leucodepletion status of the PRBC’s. The clinical records and the reaction workup done to rule out the hemolytic reactions were recorded.Results: Reactions were recorded in 17 (0.97%) out of a total of 1750 transfusions. 14 (4.1%) reactions were recorded on transfusions of non-leukoreduced PRBCs whereas only 2 (0.16%) reactions were recorded in leucoreduced (buffy coat) PRBCs. 1 (0.8%) reaction was recorded on transfusion of leucodepleted PRBCs done by bedside filter. No reaction was documented when buffy coat leucoreduced PRBCs were used along bedside filter.Conclusions: Elimination of WBCs from donor packed cells results in reduction of adverse reactions following blood transfusion. Various methods of leucoreduction have been successfully employed in the past and shown to reduce transfusion reactions in multi transfused thalassemic patients. In resource limited settings, leukoreduction using the buffy-coat method is an effective intervention in reducing the transfusion reactions

A Hybrid Secure Cloud Platform Maintenance Based on Improved Attribute-Based Encryption Strategies

In the modern era, Cloud Platforms are the most needed port to maintain documents remotely with proper security norms. The concept of cloud environments is similar to the network channel. Still, the Cloud is considered the refined form of network, in which the data can easily be stored into the server without any range restrictions. The data maintained into the remote server needs a high-security feature, and the processing power of data should be high to retrieve the data back from the respective server. In the past, there were several security schemes available to protect the remote cloud server reasonably. However, the attack possibilities over the cloud platform remain; only all the researchers continuously work on this platform without any delay. This paper introduces a hybrid data security scheme called the Improved Attribute-Based Encryption Scheme (IABES). This IABES combines two powerful data security algorithms: Advanced Encryption Standard (AES) and Attribute-Based Encryption (ABE) algorithm. These two algorithms are combined to provide massive support to the proposed approach of data maintenance over the remote cloud server with high-end security norms. This hybrid data security algorithm assures the data cannot be attacked over the server by the attacker or intruder in any case because of its robustness. The essential generation process generates a credential for the users. It cannot be identified or visible to anyone as well as the generated certificates cannot be extracted even if the corresponding user forgets the credentials. The only way to get back the certification is resetting the credential. The obtained results prove the accuracy level of the proposed cypher security schemes compared with the regular cloud security management scheme, and the proposed algorithm essential generation process is unique. No one can guess or acquire it. Even the person may be the service provider or server administrator. For all, the proposed system assures data maintenance over the cloud platform with a high level of security and robustness in Quality of Service

High-spin spectroscopy in 207^{207}At: Evidence of a 29/2+^{+} isomeric state

Yrast and near-yrast states above the known 25/2$^{+}$ isomer in $^{207}$At are established for the first time. The level scheme is extended up to 47/2$\hbar$ and 6.5 MeV with the addition of about 60 new $\gamma$-ray transitions. The half-life of the 25/2$^{+}$ isomer is revisited and a value of $T_{1/2}$ = 107.5(9) ns is deduced. Evidence of a hitherto unobserved 29/2$^{+}$ isomer in $^{207}$At is presented. A systematic study of $B(E3)$ values for the transitions de-exciting the 29/2$^{+}$ isomer in the neighboring odd-$A$ At isotopes suggests a half-life in the 2$-$4 $\mu$s range for this state in $^{207}$At. The experimental results are compared with large-scale shell-model calculations performed using the KHM3Y effective interaction in the $Z$ = 50$-$126, $N$ = 82$-$184 model space and an overall good agreement is noted between the theory and the experiment. A qualitative comparison of the excited states and the isomers with analogous states in neighboring nuclei provides further insight into the structure of $^{207}$At.Comment: 15 pages, 13 figure

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe