Cross-Layer Treatment of Mobility for Mobile Ad Hoc Networks

The current era of mobile communication is passing through the days of rapidly changing technologies. Such an evolving promising technology is mobile ad hoc networks (MANETs). The communications in ad hoc networks are adversely affected by the link failures in the network layer, and by the hidden station, mobile hidden station, neighborhood capture and asymmetric radio link problems in the MAC layer. All the problems are highly affected by mobility of the stations. If the degree of mobility of any station in a route increases, the route life time decreases. That causes frequent link failures, and results packet retransmissions, additional latency and packet loss. An algorithm to include mobility in a routing protocol to reduce packet losses in a MANET is proposed in this thesis. The proposed algorithm estimates the number of packets that can traverse through the route before it breaks because of mobility. The algorithm is implemented in dynamic source routing protocol, and simulated in Network Simulator-2. The MHS problem arises if a station is hidden due to mobility. Asymmetric/unequal radio links in can occur in MANETs/VANETs for many reasons such as hardware limitations, power saving protocols, shadowing effects, dynamic spectrum managements. A MAC protocol named extended reservation Aloha (ERA) is proposed which partially solves these problems. Then, using the concept of ERA, another MAC protocol named extended sliding frame reservation Aloha (ESFRA), which addresses all the above mentioned MAC problems, is proposed in this thesis. As safety critical information dissemination in DSRC/WAVE systems requires reliability and robustness, a network-MAC cross-layer information dissemination protocol is proposed in this thesis to address those issues. Although the layered architecture is still a good candidate for any design of wireless networks, the researchers are looking for some optimizations by interaction between neighbor layers which is called cross-layer design. So I proposed a network-MAC cross-layer algorithm, cross-layer extended sliding frame reservation Aloha (CESFRA), which solves mobility related problems, confirms low and deterministic end-to-end delay, and is robust and reliable in safety critical information dissemination up to 3rd hop. Discrete time Markov chain (DTMC) and OMNeT++ are used for all the MAC layer analyses

COVID-19 and Tuberculosis: A perspective of Bangladesh

Tuberculosis is our old enemy while COVID-19 (Coronavirus disease 2019) is a novel one. Both diseases have many similarities in terms of target organ affected, transmission, clinical presentations. COVID-19 is a fast-track novel pandemic while tuberculosis is a slow-moving pandemic. As control measures, countries all over the globe have enforced lockdown to halt the spread of the SARS-CoV-2 virus, but this stringent method has a negative impact on access to the health care delivery system. It seems that there is a dropping of new case findings, but modeling projection by WHO estimates that the total number of tuberculosis cases will rise by 2025. Bangladesh is a high Tuberculosis burden country in the south Asia region. Worldwide COVID-19 has a negative impact on tuberculosis diagnosis and management strategy. Bangladesh has impending threat to rise in tuberculosis case in future because of lockdown process, densely populated nation, poverty, reallocation of tuberculosis diagnostic facility and trained staff to diagnose COVID-19 and collapse of DOTS (directly observed treatment, short-course) program of NTP (national tuberculosis control program), rampant use of immunosuppressant’s including steroid, biologics. Prompt tuberculosis case detection, digital supervised drug delivery, avoidance of injudicious use of steroids, biologics to treat COVID-19, and testing for both COVID-19 and tuberculosis should be simultaneously undertaken to tackle this overwhelming situation. Eradication of psycho-social stigma about these two diseases is essential for preventing a perfect storm. BSMMU J 2022; 15(1): 54-5

A clinical study of arrhythmias associated with acute coronary syndrome: a hospital based study of a high risk and previously undocumented population

Background: ACS represents a global epidemic. Arrhythmia in ACS is common. Careful investigation may lead to further improvement of prognosis. Retrospectively analyzed the year- round data of our center. Study was undertaken to analyze the incidence, frequency and type of arrhythmias in ACS. This is to aid timely intervention and to modify the outcome. Identification of the type of arrhythmia is of therapeutic and prognostic importance.Methods: This cross sectional analytical study was conducted in the Department of Cardiology, Apollo Hospitals Dhaka, from January 2019 to January 2020 with ACS patients. Enrolled consecutively and data analyzed.Results: There were 500 patients enrolled considering inclusion and exclusion criteria. Sample was subdivided into 3 groups on the type of ACS. Group-I with UA, Group-II with NSTE - ACS and Group-III with STE - ACS. Different types of arrhythmia noted. Types of arrhythmia were correlated with type of ACS. 500 patients included. Mean age 55.53±12.70, 71.6% male and 28.4% female. 60.4% hypertensive, 46.2% diabetic, 20.2% positive family history of CAD, 32.2% current smoker, 56.4% dyslipidaemic and 9.6% asthmatic. 31.2% UA, 39.2% NSTE-ACS and 29.6% STE-ACS. Type of arrhythmias noted. 22% sinus tachycardia, 20.2% sinus bradycardia, 9% atrial fibrillation, 5.2% ventricular ectopic, 4.8% supra ventricular ectopic, 2.8% bundle branch block, 2.2% atrio-ventricular block, 1% broad complex tachycardia, 0.4% narrow complex tachycardia, 0.2% sinus node dysfunction and 32.2% without any arrhythmia. Significant incidences of arrhythmia detected - respectively 29.8%, 39.2% and 31%, p<0.001.Conclusions: In conclusion, arrhythmias in ACS are common. More attention should be paid to improve their treatment and prognosis

Evaluation of the Current RE Methods against the Typical Requirements of Wearable Computer

Abstract. Day by day, computing is going to be more punctilious in size and functionalities, faster in communication, more effective and reliable in awareness, more flexible and user friendly in behaviour and very much constant in operation and interaction. Such a computer which fulfils all the above requirements is wearable computer, a computer that is subsumed in the personal space of the user. Though the entry of wearable computer into the computer world was not so remarkable and admirable, it is getting attracted by the current civilization day by day for the realization of its requirements for the future world. A person busy with several workloads at the same time likes to acquire much more output from the same span of time and wearable computer substantiates this type of un-restriction. This is one of the most important and salient features of wearable computer and this type of typical, goal oriented requirements of wearable computer are the point of discussion of this paper. An empirical study of the requirements of wearable computer has been done in the SoftWEAR project led by University of Hohenheim and IAO, Fraunhofer, Stuttgart. This paper will organise these requirements according to current RE methods. This kind of requirement analysis based on current RE methods might identify important research issues for the enthusiastic researchers in this field and ascertain potentially fruitful future research directions in a conducing environment.

Elevated concentrations of serum matrix metalloproteinase-2 and -9 and their associations with circulating markers of cardiovascular diseases in chronic arsenic-exposed individuals

Background: Cardiovascular diseases (CVDs) and cancers are the major causes of chronic arsenic exposure-related morbidity and mortality. Matrix metalloproteinase-2 (MMP-2) and −9 (MMP-9) are deeply involved in the pathogenesis of CVDs and cancers. This study has been designed to evaluate the interactions of arsenic exposure with serum MMP-2 and MMP-9 concentrations especially in relation to the circulating biomarkers of CVDs. Methods: A total of 373 human subjects, 265 from arsenic-endemic and 108 from non-endemic areas in Bangladesh were recruited for this study. Arsenic concentrations in the specimens were measured by inductively coupled plasma mass spectroscopy (ICP-MS) and serum MMPs were quantified by immunoassay kits. Results: Serum MMP-2 and MMP-9 concentrations in arsenic-endemic population were significantly (p &lt; 0.001) higher than those in non-endemic population. Both MMPs showed significant positive interactions with drinking water (rs = 0.208, p &lt; 0.001 for MMP-2; rs = 0.163, p &lt;0.01 for MMP-9), hair (rs= 0.163, p &lt; 0.01 for MMP-2; rs = 0.173, p &lt; 0.01 for MMP-9) and nail (rs= 0.160, p &lt; 0.01 for MMP-2; rs = 0.182, p &lt; 0.001 for MMP-9) arsenic of the study subjects. MMP-2 concentrations were 1.02, 1.03 and 1.05 times, and MMP-9 concentrations were 1.03, 1.06 and 1.07 times greater for 1 unit increase in log-transformed water, hair and nail arsenic concentrations, respectively, after adjusting for covariates (age, sex, BMI, smoking habit and hypertension). Furthermore, both MMPs were increased dose-dependently when the study subjects were split into three (≤10, 10.1-50 and &gt; 50 μg/L) groups based on the regulatory upper limit of water arsenic concentration set by WHO and Bangladesh Government. MMPs were also found to be significantly (p &lt; 0.05) associated with each other. Finally, the concentrations of both MMPs were correlated with several circulating markers related to CVDs. Conclusions: This study showed the significant positive associations and dose–response relationships of arsenic exposure with serum MMP-2 and MMP-9 concentrations. This study also showed the interactions of MMP-2 and MMP-9 concentrations with the circulating markers of CVDs suggesting the MMP-2 and MMP-9 -mediated mechanism of arsenic-induced CVDs