High-Power T/R circuits for a Multichannel VHF/UHF/HF Ice Imaging Radar

This thesis presents the design and implementation of high power, wide bandwidth transmit/receive (T/R) switches and modules for use in multi-channel ice-penetrating imaging radars. The switches were designed to address the lack of standard off-the shelf (COTS) devices that meet our technical requirements. The design of these switches was accomplished using electronic design automation (EDA) tools and implemented with quadrature hybrids and actively biased PIN diodes. Three different circuits were developed for three different frequency bands: 160-230 MHz (VHF band), 150-600 MHz (VHF/UHF), and 10-45 MHz (HF band). The circuits are capable of transmitting at least 1000 W of peak power and exhibit an insertion loss lower than 1.3 dB for 160-230 MHz, 1.6 dB for 150-600 MHz, and 2.39 dB for 10-45 MHz ranges. A fourth, miniaturized prototype for the 160-230 MHz range was implemented for use in future multi-channel systems. The circuits developed exhibit turn-on times better than 1.3 µs for the VHF/UHF circuits; and 1.5 µs for the HF circuits. The turn-off times were better than 200 ns for the first two bands and 1.36 µs for the HF band. Both the VHF and VHF/UHF have been demonstrated in field operations with two different radar systems

Telemedicine, Not The Panacea We Thought It Would Be. A Tale Of Caution

In the last few decades, the growing use of telemedicine has allowed access to healthcare at reduced costs and increased monitoring of chronic conditions, especially in underserved and rural areas. It is a tool of great value in low-income countries where there is a paucity of specialists. In the height of the COVID-19 pandemic, telemedicine was used to screen patients with COVID-19 like symptoms and send them to test sites directly. This helped minimize unnecessary healthcare staff and patient exposure to the infection and helped decompress ERs. Due to a lack of testing resources, many mildly symptomatic patients were presumed to have COVID-19 infection and advised to self-isolate at home. We present a case of delayed diagnosis of acute leukemia resulting in a life-threatening presentation with leukostasis. This case highlights the need for a physical exam, lab investigations, and close follow-up for new patient complaints seen over telemedicine. It also highlights the lack of evidence for the efficacy and safety of telemedicine in patients with new complaints

A review on optimization of vehicle frontal crashworthiness for passenger safety

In engineering and technology safety of human life has always been a top priority. With the increasing usage of vehicles in everyday life, probability of deaths and injuries has also increased. This paper provides a critical review on the optimization of vehicle frontal crashworthiness studied by researchers using various methods. They investigated the effects of crash at a defined speed using the method of FRB and ODB impact. It further discusses other methods that can be used to save passengers’ life. Also, the designing and manufacturing limitations faced by engineers in actual development processes. Finally, it is concluded that improved structure design and material composition can significantly increase the overall crashworthiness of the vehicle

Visualization representation benefits of pre-requirement specification tractability

Representation of Pre-RST information is very useful using visualization elements for realization of benefits of requirements tractability This improves the practitioners motivation to maintain Pre-RST information during life cycle processes. Few researchers proposed visualization for post-RST due to which many benefits of requirements tractability cannot be realized. This paper proposed an important visualization representing Pre-RST information that demonstrate various benefits of requirements tractability. In order to evaluate empirically an experiment is conducted and textual representation of tractability information is obtained. In order to strengthen our claim a survey is conducted to compare textual representation of tractability information with proposed visualization and results are compiled

Drinking water quality in Rohri City, Sindh, Pakistan

Groundwater and surface water samples from Rohri city were analyzed for the presence of total coliform (TC), E. coli (Ec) and heterotrophic plate count (HPC). The samples were collected before and after storage. The bacteriological analysis was carried out by membrane filtration and spread plate count (SPC) technique. The pre-storage ground water samples were found to be contaminated with TC (25%), Ec (12.5%) and HPC (45%). All post-storage groundwater samples were found to be contaminated with TC (100%), Ec (41.6%) and with HPC (100%); the number of TC, Ec and HPC in post-storage groundwater samples was very high. The difference in number of colony forming units (cfu/100ml) between pre and post-storage groundwater samples was significant (p= 0.0001). The pre-storage surface water samples from main storage reservoirs and post-storage surface water samples from households were also found to be contaminated with TC (100%), Ec (100%) and HPC (100%). A significant (p= 0.002) difference in the number of cfu/ 100ml of ground water and in surface water samples was recorded. The quality of surface water was very poor as compared to groundwater in terms of microbial content and further declined after storage indicating lack of hygiene in the study  populationKey words: Groundwater, households, gastroenteritis and waterborne

A comparison between solar thermal and photovoltaic/thermal (PV/T) systems for typical household in Libya

—The fossil fuel in Libya produces the most of the generated electricity. As the energy demand will escalate significantly in the near future, more oil and gas are consumed and hence more CO2 emission. Therefore, for a sustained development the renewable energy must share in the electricity market. The special location of Libya in the highest sunny belt makes the solar energy one of the best alternative energy supplier. This paper is aimed at proposing an effective solution to enhance continuous power availability and to reduce the peak load demand in Libyan electric grid through replacing the electric heaters with Domestic Solar Water Heating (DSWH). Two alternatives are analyzed; photovoltaic-solar water heating (PV-SWH) system and photovoltaic-photovoltaic/thermal (PVPV/T). The two options are compared in terms of the capital cost, maintenance cost, total cost, fuel cost and the CO2 emission. The results show that the total energy saving for the PV-SWH system is around 69.79% of the total energy required. Furthermore, the total energy saving for the PV-PV/T system is about 75.02% of the net energy need

An implementation of electroencephalogram signals acquisition to control manipulator through brain computer interface

Brain computer interface (BCI) technology can be used to design a robotic arm whose decision would be based on the brain activity and brain signals. This proposed design can be more beneficial for the paralyzed people and the patients who are suffering from Amyotrophic lateral sclerosis (ALS), Locked in syndrome (LIS), or neurodegenerative disease. Due to these disease patients would not be able to hold and grip the objects properly. Extensive literature review showed that various EEG signal analysis has been completed with the accuracy of 70% to 85%. The suggested solution would be beneficial to the patients in terms of performing every day functions easily like draws opening, holding dishes and opening and closing of doors as well with more accuracy. In the proposed research electroencephalogram signals were observed and used to classify the type of the motion. Data acquisition comprised of three stages amplification can be considered as cost effective signal conditioning. High pass filter, low pass filter and then converted from analog to digital. Open vibe software was used to design the basic neuron scenario for the brain signals and then classified into alpha and beta waves. Robotic arm movement was based on the alpha and beta waves were performed precisely. Simulated results proved that proposed EEG signals acquisition performed better and can be acknowledged as cost effective. Researchers showed the successful execution of the brain wave signal classification with less false alarm rate for the robotic arm movement by modulation, digitization of the brain signal. Moreover, comparative analysis has been performed of Quadratic Discriminant analysis, k-NN and Medium Gaussian SVM in terms of accuracy prediction speed and training time. Comparative analysis proved that Medium Gaussian SVM worked better than the other classifiers with the accuracy of 95.8%. It was also proved that Medium Gaussian classifier has the capability to predict 10000 observations per second in 0.75466 training time. © 2019 IEEE

Robotic exoskeleton control for lower limb rehabilitation of knee joint

Wearable devices such as exoskeletons are being opted frequently during rehabilitation processes for the post stroke recovery. Such de-vices are playing important role in the development of assistive rehabilitation robotic systems. In this paper three control strategies MPC and LQR and PID are introduced which were applied to knee joint of lower limb exoskeleton model for passive exercise. The two con-trols MPC and LQR are model based control which empowers them for stable responses. In this paper the analysis of robustness of con-trol is done under the noisy and disturbance conditions. The results showed good performance of the exoskeleton model with the applied controls in the provided condition. In the future work the applied controls will be implemented on hardware

Professionalism in medical students at a private medical college in Karachi, Pakistan

Objective: To determine levels of professionalism in undergraduate medical students at a private medical college and assess how changes emerge during their training. Methods: The study was conducted at Aga Khan University, a tertiary care teaching hospital, during November and December 2011. Freshmen, Year 3 and Year 5 students were requested to fill out a questionnaire. It was designed to assess the participants\\u27 levels of professionalism and how they perceived the professional environment around them by incorporating previously described scales. The questionnaire was re-validated on a random sample of practising clinicians at the same hospital. SPSS 17 was used for statistical analysis. Results: The study sample comprised 204 participants. The mean score for level of individual professionalism was 7.72±3.43. Only 13 (6.4%) students had a score one standard deviation above the faculty mean. About 24 (11.8%) were one standard deviation and 35 (17.2%) were 2 standard deviations below the faculty mean. The remaining 130 (63.7%) were \u3e2 standard deviations below the faculty mean. Considering the level of education, the mean score for level of professionalism was 8.00±3.39 for freshmen, 6.85±3.41 for year 3 students, and 8.40±3.34 for year 5 students. Conclusion: The currently employed teaching practices inculcating the values of professionalism in medical students are serving as a buffer to maintain the pre-training levels of professionalism from declining

What constitutes responsiveness of physicians: A qualitative study in rural Bangladesh

Responsiveness entails the social actions by health providers to meet the legitimate expectations of patients. It plays a critical role in ensuring continuity and effectiveness of care within people centered health systems. Given the lack of contextualized research on responsiveness, we qualitatively explored the perceptions of outpatient users and providers regarding what constitute responsiveness in rural Bangladesh. An exploratory study was undertaken in Chuadanga, a southwestern Bangladeshi District, involving in-depth interviews of physicians (n = 17) and users (n = 7), focus group discussions with users (n = 4), and observations of patient provider interactions (three weeks). Analysis was guided by a conceptual framework of responsiveness, which includes friendliness, respecting, informing and guiding, gaining trust and optimizing benefits. In terms of friendliness, patients expected physicians to greet them before starting consultations; even though physicians considered this unusual. Patients also expected physicians to hold social talks during consultations, which was uncommon. With regards to respect patients expected physicians to refrain from disrespecting them in various ways; but also by showing respect explicitly. Patients also had expectations related to informing and guiding: they desired explanation on at least the diagnosis, seriousness of illness, treatment and preventive steps. In gaining trust, patients expected that physicians would refrain from illegal or unethical activities related to patients, e.g., demanding money against free services, bringing patients in own private clinics by brokers (dalals), colluding with diagnostic centers, accepting gifts from pharmaceutical representatives. In terms of optimizing benefits: patients expected that physicians should be financially sensitive and consider individual need of patients. There were multiple dimensions of responsiveness- for some, stakeholders had a consensus; context was an important factor to understand them. This being an exploratory study, further research is recommended to validate the nuances of the findings. It can be a guideline for responsiveness practices, and a tipping point for future research