GSM based Communication-Sensor (CommSense) System

Using communication signals for radar applications has been a major area of research in radar engineering. In the recent years, due to the widely available wireless signals, a new area of research called commensal radars has emerged. Commensal radars use available wireless Radio Frequency (RF) signals to detect and track targets of interest. This is achieved by placing two antennas, one towards the transmitting base station and the other towards the surveillance area. The signal received by these two antennas are correlated to determine the location and velocity of the target. When a signal passes through a channel, it reflects off the obstacles within its path. These reflections usually degrade quality of the signal and cause interference to the telecommunication systems. To mitigate the effects of the channel on a signal these systems transmit a known bit sequence within each frame. Our goal, with this thesis, is to design and implement a working prototype of a novel architecture for the commensal radar system, which uses these known bit sequences to extract the channel information and determine events of interest. The major novelties of the system are as follows. Firstly, this system will be built upon existing communication systems using Software Defined Radio (SDR) technology. Secondly, this design eliminates the need for a reference antenna, which reduces the cost of the system and creates an opportunity to make the system portable. We name this system Communication-Sensing (CommSense). Since, our plan is to use Global System for Mobile Communication (GSM) as the parent system for the prototype development, we decide to update the name to GSM based Communication-Sensing (GSM-CommSense) system. This thesis begins with theoretical analysis of the feasibility of the GSM-CommSense system. First of all, we perform a link budget analysis to determine the power requirements for the system. Then we calculate the ambiguity function and Cram´er-Rao Lower Bound (CRLB) for a two-path received signal model. With encouraging theoretical results, we design a prototype of the system that can capture real GSM base station broadcast signals. After the design of the GSMCommSense system, we capture channel data from multiple locations with varying environmental conditions. The aim for this set of experiment is to be able to distinguish between different environmental conditions. Then, we performed statistical analysis on the data by means of Probability Density Function (PDF) fitting, a goodness-of-fit test called chi-square test and a clustering algorithm called Principal Components Analysis (PCA). We have presented the results from each analysis and discussed them in detail. Upon, receiving positive results in each step we have decided to move towards using learning algorithms to categorise the data captured by the system. We have compared two widely accepted supervised learning algorithms, called Support Vector Machines (SVM) and Multi-Layer Perceptron (MLP). The results showed that with the current hardware capabilities of the system and the amount of data available per GSM frame, the performance of SVM is better than MLP. Thus, we have used SVM to classify two events of detection and classification across a wall. We have presented our findings and discussed the results in detail. We conclude our current work and provide scope for future work in development and analysis of the GSM-CommSense system

Outcome of surgical management of ruptured Achilles tendon

Introductions: The incidence of Achilles tendon rupture has been increasing worldwide. The optimal management of this problem is controversial but the surgical intervention is being applied widely. Methods: We retrospectively analyzed patients who had Achilles tendon (AT) rupture treated surgically at Patan Academy of Health Sciences from January 2010 to December 2015. Functional outcome assessment of ankle was done by using American Orthopedic foot and Ankle Society Score (AOFAS). Results: Total 71 patients (male 45, female 26) had surgery for AT, 38 right and 33 left side. The mean age of the patient was 36.14 years (range 18-67 years). The mean AOFAS score was 83.32 (range 75-93) after first year follow up and 90.36 (range 80-99) after second year, difference was statistically significant (p<0.05). Conclusions: The study showed high AOFAS score for surgical management of ruptured Achilles tendon.   Key words: Achilles tendon rupture, American Orthopedic foot and Ankle Society Score (AOFAS

Orthopaedic services during COVID-19 lockdown at Patan Hospital, Nepal

Introduction: The COVID-19 pandemic has paralyzed the world, including elective health care services. To prevent the spread of infection, most countries have gone into lockdown and adjustments have been made to provide urgent medical care, including Orthopaedic services. In accordance with the guidelines from worst affected countries and neighboring India, Patan Hospital followed instructions from Ministry of Health and Population to provide only urgent and semi-urgent Orthopaedic services. This study aims to audit the patient profile during lockdown so as to have a clearer picture, which will enable us to be prepared for similar epidemic in the future. Method: All patients admitted to the Orthopaedic ward of Patan hospital from 24 March to 27 April 2020, during the lockdown, were included. Clinical profile, including cause of admission, management, hospital stay were descriptively analyzed. Ethical approval was obtained. Result: Out of 44 admissions, there were male 27 and female 17. Trauma cases were 38, and 18 were in age group 20-26 years. Admission due to infections were four. Conservative management were done in seven while 33 were treated surgically, out of which 30 accounted for trauma. Average 6.14 days hospital stay, range 1-22 days. Conclusion: Trauma comprised of major bulk of patients seeking urgent Orthopaedic care. Hospital needs to be prepared with necessary measures to ensure safety of health care workers and yet provide urgent Orthopaedic services. Keyword: COVID-19, lockdown, orthopaedic

Association of Panton Valentine Leukocidin (PVL) genes with methicillin resistant Staphylococcus aureus (MRSA) in Western Nepal: a matter of concern for community infections (a hospital based prospective study)

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. Panton Valentine leukocidin (PVL) is considered one of the important virulence factors of S. aureus responsible for destruction of white blood cells, necrosis and apoptosis and as a marker of community acquired MRSA. This study was aimed to determine the prevalence of PVL genes among MRSA isolates and to check the reliability of PVL as marker of community acquired MRSA isolates from Western Nepal. METHODS: A total of 400 strains of S. aureus were collected from clinical specimens and various units (Operation Theater, Intensive Care Units) of the hospital and 139 of these had been confirmed as MRSA by previous study. Multiplex PCR was used to detect mecA and PVL genes. Clinical data as well as antimicrobial susceptibility data was analyzed and compared among PVL positive and negative MRSA isolates. RESULTS: Out of 139 MRSA isolates, 79 (56.8 %) were PVL positive. The majority of the community acquired MRSA (90.4 %) were PVL positive (Positive predictive value: 94.9 % and negative predictive value: 86.6 %), while PVL was detected only in 4 (7.1 %) hospital associated MRSA strains. None of the MRSA isolates from hospital environment was found positive for the PVL genes. The majority of the PVL positive strains (75.5 %) were isolated from pus samples. Antibiotic resistance among PVL negative MRSA isolates was found higher as compared to PVL positive MRSA. CONCLUSION: Our study showed high prevalence of PVL among community acquired MRSA isolates. Absence of PVL among MRSA isolates from hospital environment indicates its poor association with hospital acquired MRSA and therefore, PVL may be used a marker for community acquired MRSA. This is first study from Nepal, to test PVL among MRSA isolates from hospital environment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-016-1531-1) contains supplementary material, which is available to authorized users

Statistická analýza pozemního clutterů z pasivního radaru založeného na FM

Statistical characterization of ground clutter information for radar systems is a topic that requires a detailed understanding. In this work, we characterize the ground clutter information from data captured by two Frequency Modulation (FM) based passive radar systems placed at different locations in the Czech Republic. Since the target models are statistically defined by the Swerling models, each of which is based on a particular distribution, we attempted to connect the ground clutter with some of the known distributions. The analysis is performed in three steps. The empirical distribution is fitted with some of the well-known distributions. Two different goodness-of-fit tests (named chi-squared test and Kolmogorov-Smirnov test) are performed on the obtained data by comparing the empirical distribution with the fitted distributions to determine which distribution is the best fit. The observations are analyzed and the results are considered in detail.Statistická charakterizace informací o pozemských clutterech pro radarové systémy je téma, které vyžaduje podrobné porozumění. V této práci charakterizujeme informace o pozemním clutteru z dat zachycených dvěma pasivními radarovými systémy založenými na frekvenčních modulacích (FM) umístěných na různých místech v České republice. Protože cílové modely jsou statisticky definovány Swerlingovými modely, z nichž každý je založen na konkrétní rozložení, pokusili jsme se propojit pozemní clutter s některými známými rozloženími. Analýza se provádí ve třech krocích. Empirické rozdělení je vybaveno některými známými rozloženími. Na základě získaných dat porovnáním empirického rozdělení s nasazeným rozdělením se provedou dva různé testy správnosti přizpůsobení (pojmenované chi-kvadrát a test Kolmogorov-Smirnov), aby se určilo, které rozdělení je nejvhodnější. Pozorování jsou analyzována a výsledky jsou podrobně zvažovány

Klasifikace dat CommSense pomocí učících algoritmů

In our previous work we have shown the design of a Communication based Sensing (CommSense) system. The current work presents analysis of the data captured by a CommSense system. Analysis is performed using Support Vector Machines (SVM) and a Multi-layer Perceptron (MLP) which are commonly used supervised learning algorithms. The predicted results are presented in the form of a confusion matrix and an analysis is presented showing the percentage of error in prediction.V dřívějších pracích jsme ukázali návrh komunikačního systému Sensing (CommSense). Současná práce představuje analýzu dat zachycených systémem CommSense. Analýza se provádí pomocí podpůrných vektorových strojů (SVM) a vícevrstvého perceptronu (MLP), které jsou běžně používané algoritmy pro dohled. Předpokládané výsledky jsou prezentovány ve formě tabulky a je prezentována analýza ukazující procentní podíl chyb v predikci

Statistical analysis of ground clutter from FM based passive radar

Statistical characterization of ground clutter information for radar systems is a topic that requires a detailed understanding. In this work, we characterize the ground clutter information from data captured by two Frequency Modulation (FM) based passive radar systems placed at different locations in the Czech Republic. Since the target models are statistically defined by the Swerling models, each of which is based on a particular distribution, we attempted to connect the ground clutter with some of the known distributions. The analysis is performed in three steps. The empirical distribution is fitted with some of the well-known distributions. Two different goodness-of-fit tests (named chi-squared test and Kolmogorov–Smirnov test) are performed on the obtained data by comparing the empirical distribution with the fitted distributions to determine which distribution is the best fit. The observations are analyzed and the results are considered in detail

Threat of multidrug resistant Staphylococcus aureus in Western Nepal

Objective: To determine the prevalence of methicillin resistant Staphylococcus aureus (MRSA) and antimicrobial susceptibility patterns of the isolates from Manipal Teaching Hospital, Pokhara, Nepal. Methods: This study was conducted over a period of 11 months (September 2012–August 2013) at the Manipal Teaching Hospital, Pokhara, Nepal. A total of 400 isolates were collected from various clinical specimens including hospital units (operation theaters and intensive care units). Antibiotic susceptibility testing was performed by Kirby-Bauer disc diffusion method. Primary screening for MRSA was performed using disc diffusion test by cefoxitin (30 μg) and oxacillin (1 μg) disc, further confirmation was done by detection of mecA gene using PCR. Results: Out of 400 Staphylococcus aureus strains, 139 (34.75%) were found to be MRSA. Among the MRSA isolates, 74 (53.2%) were from inpatient departments, 58 (41.7%) of the isolates were from outpatients and 7 (5.0%) isolates were from hospital units (operation theaters and intensive care units). Majority of MRSA (73.38%) isolates were multidrug resistant while less than 15% were resistant to amikacin, clindamycin and tetracycline. None of the isolate was resistant to vancomycin. Inducible clindamycin resistance was found in 54 (25.47%) isolates. Conclusions: This study showed a high prevalence of MRSA in our hospital. There is need of regular surveillance of antibiotic resistance, standardization of laboratory methods for detecting methicillin resistance and performing antibiotic susceptibility testing in developing countries like Nepal. Hospital acquired infections including prevalence of MRSA can be minimized by appropriate hygienic measures in patient care and management and by antibiotic stewardship. Screening of erythromycin resistant isolates would minimize clinical failures associated with clindamycin therapy