126 research outputs found
Association of Wilms Tumor with Crossed Fused Renal Ectopia in Children: A Case Report
No full textIntroduction: Wilms tumor is the most common renal malignancy in children. The occurrence of Wilms tumor with various congenital genitourinary anomalies has been reported, particularly in horseshoe kidneys, hypospadias, disorder of sexual development, and double collecting system. However, Wilms tumor with crossed renal ectopia is a rare finding.
Case Description: We are reporting a case report of Wilms tumor in a 3-year-old girl who presented with a huge left flank mass with cross-fused renal ectopia. After the initial workup and triphasic computed tomography (CT) scan of the chest, abdomen, and pelvis for confirmation of diagnosis and metastasis, the patient underwent image-guided tissue biopsy followed by neo-adjuvant chemotherapy, left radical nephrectomy with separation of fused right ectopic renal moiety and adjuvant chemoradiation.
Practical Implication: This report shows an association of Wilms tumor with cross-fused renal ectopia, a rare combination. Unusual findings on imaging with unilateral flank mass should be considered as part of the differential diagnosis for this rare finding. Adjuvant chemotherapy and modern imaging helped delineate the anatomy and ease the surgery for safe resection, improving the overall outcome
Statistical analysis of received signal strength in fog using sliding window technique for FSO links
No full textTime Synchronization in Photon-Limited Deep Space Optical Communications
No full textRandom jitter or offset between the transmitter/receiver clocks is an important parameter that has to be accurately estimated for optimal detection of pulse position modulation (PPM) symbols for high-data-rate optical communications. This parameter, in general, is modeled as an unknown random quantity that depends on the clock drift between the transmitter/receiver clocks and the random motion between the transmitter and receiver stations. In this paper, we have modeled the time jitter for two scenarios - phase modulation jitter and frequency modulation jitter. The phase modulation jitter is modeled as a Gaussian random variable which is estimated with the help of a maximum a posteriori probability (MAP) estimator. The frequency modulation jitter is characterized as a random walk, and this leads to the modeling of the jitter as a state space variable in the context of a dynamical system. Since the observations are the photon counts in each slot of a PPM symbol (for both MAP estimation and tracking), the resulting dynamical model is highly nonlinear, and particle filters are employed for tracking the frequency modulation jitter. We evaluate the performance of both the maximum a posteriori estimators and the particle filters in terms of the relative mean-square error and probability of error. We conclude that with MAP estimation and particle filters that estimate/track the time offset, we achieve a significant performance gain in terms of probability of error as compared to systems that do not have a time synchronization system in place
Analysis of Continental Fog Micro-physical Parameters: Effect of PSA on Optical Attenuation
No full textDeterminants of Bank Liquidity: Evidence from Local, Foreign and Islamic Commercial Banks in Pakistan
No full textThe purpose of this paper is to investigate the effects of bank-specific variables (i.e. bank size, profitability, deposits, cost of funds and capital ratio) on liquidity of local, foreign and Islamic commercial banks in Pakistan. Data was obtained from the publications of SBP titled ‘Financial Statement Analysis of Financial Firms’. Data of 26 banks found completed during 2007-2015 (i.e. 19 local banks, 02 foreign banks and 05 Islamic banks). Pooled OLS method used to analyze the effects of internal variables on liquidity. Descriptive statistics show that foreign banks are far better than local and Islamic commercial banks in terms of profitability and liquid assets. Alternatively, Islamic banks are in a better position than local conventional banks in terms of liquid assets, deposit ratio and capital ratio. In contrast, local conventional banks are better than Islamic banks in terms of size and profitability. More importantly, Islamic commercial banks are younger than local conventional banks but amazingly having higher deposit ratio due to strong equity-base and sufficient liquid assets. Notably, the trend toward Islamic banking is increasing day-by-day which posed threats to the conventional commercial banks, and resultantly a number of conventional banks have either introduced the ‘window’ of Islamic banking or completely started the Islamic banking operations. Regression results indicate that profitability is positively while bank size, deposits, cost of fund and capital ratio is negatively related to liquidity in a sample of all banks. Deposits are positively while cost of fund is negatively linked to liquidity in a sample of local banks. Finally, bank size is the only variable that is negatively linked to liquidity of foreign and Islamic commercial banks
Residential Solar options in Karachi: comparative analysis and decision factors
No full textThe purpose of this research is to identify the factors driving the decision of potential customers in installing a solar power system in Karachi. Pakistan is currently facing an energy crisis along with economic instability leading to highest inflation rates of all times. Subsequently, the people are looking at alternatives to mitigate the inflation effects and reduce the dependency on the electricity grid, which is not only expensive but also unreliable. Solar power system is an alternative that is highly popular and has the potential to resolve these issues.
The research used interviews to collect data from customers who had already installed solar power systems at their residences to identify the factors. These interviews also brought the opportunity to understand the challenges and advantages of the solar power systems that the customers experienced firsthand. The analysis produced six decision factors that are considered by the customers when going for a solar power system installation.
It was also important to understand and test these factors with a wider audience. For this reason, data from residents of Karachi was collected using a survey questionnaire to gauge the relative importance of the identified decision factors. Out of the six factors, the top three factors were high energy bills, load shedding and energy independence.
The research also included development of a financial model that can be used in real- life scenarios for decision making on the basis of financial metrics such as payback, return on investment and internal rate of return. The model takes various economic and technical inputs into consideration and outputs a detailed sensitivity analysis that allows the customers to base their decisions on.
Based on the combined knowledge gained from this research, it is recommended that policy making should be done by the government to allow easy access to the solar power systems to the common people, especially those who belong to the lower socio-economic classes. Adequate policies cannot only support the national grid by reducing the burden on it but can also help in alleviating poverty, fight inflation, and boost the overall economic conditions of the country
Survey on limitations, applications and challenges for machine learning aided hybrid FSO/RF systems under fog and smog influence
No full textThis paper provides a concise overview of hybrid Free Space Optical (FSO)/Radio Frequency (RF) systems operating under fog and smog channels. With the rapid growth of wireless communication and the emergence of the Internet of Things (IoT) have brought about unprecedented connectivity and transformed various aspects of our daily lives. However, certain environmental conditions pose significant challenges to wireless communication systems like FSO and RF technologies. Fog and smog with its dense moisture-laden atmosphere and presence of particulate matter cause absorption and scattering of light, leading to reduced link quality and limited range for FSO communication system. Whereas, RF systems are although less affected by fog/smog as compared to rain but still have inherent limitations in terms of bandwidth and capacity. To overcome these challenges and ensure reliable communication, researchers have turned their attention to hybrid FSO/RF systems which can combine the strengths of FSO and RF technologies and mitigate the limitations of each technology. This work summarizes and explores the hybrid system architecture and machine learning techniques used to enhance the performance and adaptability of wireless communication systems. Additionally, we present the existing experimental research on hybrid FSO/RF systems, performance evaluation metrics, and future research directions to pave the way for further advancement
Optical Signal Attenuation through Smog in Controlled Laboratory Conditions
No full textFree-space optical (FSO) communication is a line-of-sight (LOS) communication technology that uses light, typically lasers, to transmit data through the atmosphere. FSO can provide high data transfer rates, but factors like weather conditions can affect its performance. Like fog, smog also degrades the availability and reliability of FSO links, as the particulate matter (PM) present in smog scatters the light beam, causing perceptible attenuation. In this paper, we have investigated the attenuation of an optical signal under laboratory-controlled smog conditions, using both theoretical and experimental approaches. A 6 m long acrylic chamber is used to contain artificial smog and measure the optical attenuation through it. The experimental result shows that smog attenuation is approximately 1.705 times more than fog attenuation. The findings of this study offer valuable insights into the effects of smog on optical links and can contribute to the development and optimization of these systems in regions with high levels of smog
- …
