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(R2060) An M/G/1 Retrial Queue with Recurrent Customers, General Retrial Times and Working Vacation
Get PDFIn this article, we analyze an M/G/1 retrial queue with recurrent customers, general retrial times and working vacation. In this model, we use two types of customers. They are recurrent customers who rejoin the retrial queue after completion of their service and transit customers who leaves the system once their service complete. All the service times and retrial times for transit customers follows general distribution, retrial time for recurrent customers and working vacation time of the server are assumed to have an exponential distribution and also service time of the recurrent customers follows general distribution. We have used working vacation which means that server serves customer at low service rate. The supplementary variable technique is used to obtain the probability generating function for the number of customers in the orbit. Here, we compute the average number of customers and waiting time in the orbit. Some of the special cases are discussed. Some numerical examples are illustrated
Performance Analysis Of Attention Based Deep Learning Models On Named Entity Recognition In Electronic Health Records
Get PDFMining Clinical Notes for relevant information has attracted a lot of interest in Natural Language Processing (NLP). Medical documents contain language whose distributions vary from that of the general domain and have a vocabulary that evolves with time. Recently, attention based deep learning language models have become the new state-of-the-art in language modeling capturing strong representations of language with respect to the context it is in, improving on classic clinical NLP task such as medication detection, and medication classification.
In this thesis research, the Harvard Medical School’s 2022 National Clinical NLP Challenges (n2c2) is considered where the Contextualized Medication Event Dataset (CMED) has been given for the challenge. CMED is a dataset of unstructured Electronic Health Records (EHRs) and annotated notes that contain task relevant information about the EHRs. The goal of the challenge is to develop effective solutions for extracting contextual information related to medications from EHRs using data driven methods. In this thesis, variations of Google’s attention-based Bert architecture have been applied for this challenge, namely, Bert Base, BioBert, and two variations of Bio+Clinical Bert, that are pre-trained on general domain, biomedical domain, and clinical domain corpora, respectively. They are used to perform named entity recognition (NER) for medication extraction and medical event detection. Pre-processing methods have been developed for breaking down EHRs for compatibility with the Bert model on NER task, and the variations of Bert are fine-tuned with CMED for the n2c2 task. Performance analysis has been carried out using a script based on constructing medical terms from the evaluation portion of CMED with metrics including recall, precision, and F1-Score. The results demonstrate that Bio+Clinical Bert outperforms Bert Base and BioBert, as well as three of the top ten performers in the challenge.
Index terms: Bi-directional encoder representations from transformers, electronic health records, natural language processing, transforme
Qualitative analysis of TB transmission dynamics considering both the age since latency and relapse
No full textSince the beginning of time, tuberculosis (TB) has been a fatal illness that predominantly affects the human lungs before spreading to other organs including the brain, spine, etc. The main elements of TB mitigation are age-dependent heterogeneity, identifying those who are latently infected, and treating them using the right diagnostic strategy. In this present work, the complex transmission mechanism of this disease in a population is described by a coupled system of integro-partial differential equations (IDE-PDE). The system\u27s well-posedness requirement is confirmed. The proposed system\u27s basic reproduction number (R0) is obtained. This work provides a complete analysis of the qualitative properties of the model, including steady state existence, asymptotic smoothness of the solution semi-flow, uniform persistence of the endemic equilibrium, and the global asymptotic stability criterion. It is observed that in assessing the severity of the pandemic, the value of R0 is crucial. Additionally, the stability results are visually illustrated by solving the model equations numerically while assuming two hypothetical cases. The current work also suggests several methods for reducing the value of the basic reproductive number (R0) by manipulating a few parameter values, which may help to lessen the prevalence of TB in a community
Kashmiri Song (Five Songs of Laurence Hope)
No full texthttps://digitalcommons.pvamu.edu/choir/1008/thumbnail.jp
Wind Energy Harvesting System For Low Wind Speeds
Get PDFIn recent years, wind energy has been one of the fastest-growing renewable energy sources because it reduces the global economy’s dependence on fossil fuels for energy generation. Despite the tremendous growth in wind power generators, modern wind power generators are not effective at low wind speeds due to many shortcomings in their advanced design features, such as large blades, tall towers, and yaw control systems. It is desirable to design wind generators that operate at low wind speed environments for electric power generation.
This research work presents the design and fabrication of a wind energy harvesting system that captures and amplifies the natural wind at low speed for improved electrical power generation. The methods used in this work include: i) the application of the flow continuity equation to convert low wind speeds to higher speeds, ii) SolidWorks 3-D simulation of the wind generator system, and iii) prototypes built to obtain measurement results. The results from the three approaches were compared.
The designed system achieved a 91% area improvement by selecting a rectangular inlet and a circular outlet compared to using a square inlet and circular outlet that had an area improvement of 27%. SolidWorks was used to perform 3-D modeling and simulate the wind energy harvesting system. SolidWorks flow simulation results showed that wind velocities increased at the output of the wind generator system. The simulation results were close to those obtained using flow continuity equation. In addition, it was found through the 3-D simulation that the wind generators with diffusers had increased output wind speeds. Furthermore, the output wind speed slightly increased when the diffuser expansion angle was increased.
Small and large prototypes of the wind generator system were built. The prototypes operate omnidirectionally by rotating in the direction of the wind, while previously reported systems do not rotate in capturing low wind speeds. In addition, the large prototype system incorporates a controller for remote monitoring and data collection. The measurement results of the prototypes are close to those obtained from the 3-D simulations. The experimental results indicate that the wind energy harvesting system can capture and significantly boost low wind speeds for improved electrical power generation.
Keywords— Continuity equation, Electric power, Low wind speeds, Omnidirectional, Prototype, SolidWork
