Performance analysis of Poisson and exponential distribution queuing model in local area network

Performance analysis of network queuing model is very important due to delay and latency that may be caused by using inappropriate model. It also impacts the utilization and throughput of the network. Many network queuing models have been proposed to be used in the network such as Poisson distribution model and Exponential distribution model. The first step in using a suitable queuing model is to know about the performance of that specific model. It means that a model with less delay and maximum utilization should be chosen to implement in the network. In this paper, performances of Poisson distribution and Exponential distribution methods in a queuing model are compared by OPNET Simulator. The behavior of these two queuing models is analyzed to find the best model in terms of queuing delay, utilization, throughput, and network load. Finally, a mathematical method is used to prove the result of simulation and find the model that performs well in the network. The results of this study show a better performance of Exponential distribute queuing model than Poisson distribute queuing model. In Exponential distribution queuing model not only does the network experience a higher throughput, but the network using Exponential distribution queuing model also maintains a less delay in the network

Non-overshooting PD and PID controllers design

This paper involves the design of non-overshooting PD and PID controllers for some special plants. The PID controller parameters are determined to reach a stable closed-loop system with monotonically decreasing frequency response. Thus specific regions in the controller parameters space are obtained. Gain crossover frequency and phase isodamping property are employed to choose an appropriate solution among the obtained solutions. The performance of the proposed PD and PID controllers in position and velocity control of a laboratory DC servomechanism system is investigated through experimental tests

An Investigation into the English Language Needs of Bank Employees of Saderat Bank in Mashhad

With the increase in marketing and trading, recognition of the need for improved English communication skills has been growing among Banking professionals. Need analysis is a chief point to consider in English for Specific Purposes (ESP ) courses for syllabus design and materials development. This study was done in order to understand to what extend Bank employees of Saderat bank in Mashhad  need to use English at the present time and future and also to find out what problems in using English they have during their work This research was done in Saderat Banks in Mashhad, in some parts of the central office such as: management department, inspection department, financial marketing and 10 branches with Foreign Exchange departments, Accounting department, Transfer department and Loan department. The participants included 70 bank employees with different job positions. They were asked to answer a questionnaire which included 33 closed questions and 1 open-ended question to identify English skills that they need in their job, the problems they have in using English and their desire for taking an English training course. Based on the data analysis it became clear that they need speaking skill the most and they have problems with all the skills. They stated that Bank should provide English training courses for them

Coupled Lattice Boltzmann Modeling Framework for Pore-Scale Fluid Flow and Reactive Transport

In this paper, we propose a modeling framework for pore-scale fluid flow and reactive transport based on a coupled lattice Boltzmann model (LBM). We develop a modeling interface to integrate the LBM modeling code parallel lattice Boltzmann solver and the PHREEQC reaction solver using multiple flow and reaction cell mapping schemes. The major advantage of the proposed workflow is the high modeling flexibility obtained by coupling the geochemical model with the LBM fluid flow model. Consequently, the model is capable of executing one or more complex reactions within desired cells while preserving the high data communication efficiency between the two codes. Meanwhile, the developed mapping mechanism enables the flow, diffusion, and reactions in complex pore-scale geometries. We validate the coupled code in a series of benchmark numerical experiments, including 2D single-phase Poiseuille flow and diffusion, 2D reactive transport with calcite dissolution, as well as surface complexation reactions. The simulation results show good agreement with analytical solutions, experimental data, and multiple other simulation codes. In addition, we design an AI-based optimization workflow and implement it on the surface complexation model to enable increased capacity of the coupled modeling framework. Compared to the manual tuning results proposed in the literature, our workflow demonstrates fast and reliable model optimization results without incorporating pre-existing domain knowledge

The comparison of predictive value of cervical length in singleton spontaneous preterm labor with in vitro fertilization pregnancies: A cohort study

Background: Preterm labor (PTL) is one of the most important factors in neonatal mortality. Some studies have revealed a reverse relationship between cervical length (CL) and PTL, however, further evidence is needed to confirm it. Objective: To investigate the predictive value of CL in spontaneous and in vitro fertilization (IVF) pregnancies. Materials and Methods: This prospective cohort study was performed on 154 pregnant women from 16-26 wk of gestation with a singleton fetus in spontaneous delivery (n = 77) and IVF pregnancies (n = 77) and followed up until delivery. Women with multiple pregnancy, placenta previa, cerclage, and congenital anomalies were excluded from the study. The cut-off determination was done according to the Roc analysis. Results: The mean CL in term delivery and PTL groups were 37 ± 7 mm and 31 ± 6 mm, respectively (p < 0.001). The frequency of PTL in spontaneous and IVF pregnancies were 7.8% and 23.27%, respectively (p = 0.007). According to the Roc analysis, the best cut-off for normal pregnancy was ≤ 36 mm with the negative predictive value of 97.9%, the positive predictive value of 11.4%, sensitivity 83.3%, and specificity of 46.5%. While for the IVF group, the cut off was ≤ 30 mm, with a negative predictive value of 88.4%, a positive predictive value of 57.8%, sensitivity of 63.2%, and a specificity of 86%. Conclusion: In this study, IVF had a significant direct correlation with PTL. CL also had a significant indirect relationship with PTL. Key words: Cervix, IVF, Preterm delivery, PTL