ISPITIVANJE UTJECAJA PRUŽANJA DISKONTINUITETA NA REGIONALNI PROTOK FLUIDA U ŠUPLJIKAVOJ STIJENI UPORABOM HIBRIDNE METODE KONAČNIH VOLUMENA I MREŽE DISKRETNIH PUKOTINA TE SIMULACIJOM STRUJNICA

Understanding the fluid behaviour in rock masses is of great importance in various rock mass-related engineering projects, such as seepage in tunnels, geothermal reservoirs, and hazardous waste disposal. Different approaches have been implemented to study the flow pattern in fractured porous rock masses. Laboratory experiments can provide good information regarding this issue, but high expenses aside, they are time-consuming and suffer the lack of ability to study field scale mediums. Numerical methods are beneficial in simulating such mediums with the Discrete Fracture Network (DFN) method in terms of costs and time as they offer sufficient flexibility and creativity. In this paper, a Matlab code was extended to study the flow regime in a Dual Permeability Media (DPM) with two point sources in the right and left side of the model as an injector and a producer well, respectively. A high permeability discontinuity with different angles was embedded in a very low-permeability limestone matrix. Pressure equations were solved implicitly with a two-point flux approximation scheme of the Finite Volume Method (FVM). Streamlines were traced in the medium and used to analyse the model’s hydraulic behaviour with the aid of Time Of Flight (TOF) for each point. The results show that the FVM-DFN hybrid method can be used as a fast method for fluid flow in DPM with the aid of streamline simulation to study the fluid flow in a large model with discontinuity.Razumijevanje ponašanja fluida u stijenskoj masi izrazito je važno kod različitih inženjerskih projekata kao što su procjeđivanje u tunelima, geotermalna ležišta te odlaganje opasnoga otpada. U proučavanju obrasca protoka fluida kroz raspucanu, šupljikavu stijensku masu korišteni su različiti pristupi. Laboratorijska istraživanja mogu pomoći u izučavanju takvih problema, međutim, osim što su skupa, zahtijevaju puno vremena i teško ih je primijeniti u makrostrukturama. Numeričke simulacije mogu opisati takve prostore metodom mreže diskretnih pukotina smanjujući troškove i vrijeme jer nude dovoljnu prilagodljivost i kreativnost. Ovdje je prikazano proširenje koda u Matlabu s ciljem izučavanja protoka u stijenskome prostoru s dvostrukom propusnošću, tj. s izvorima fluida na desnoj i lijevoj strani modela koji predstavljaju utisnu i proizvodnu bušotinu. Vrlo propusni diskontinuiteti s različitim kutovima smješteni su unutar slabopropusnoga vapnenačkog matriksa. Jednadžbe tlaka aproksimiraju izravan shematski tok između dviju točaka metodom konačnih volumena. Strujnice su praćene kroz simulirani volumen te je njima analizirano hidrauličko ponašanje modela izračunom brzine protoka u svakoj točki. Rezultati pokazuju kako hibridna metoda konačnih volumena i mreža diskretnih pukotina mogu biti korištene kao brz način opisivanja protoka fluida u prostoru s dvostrukom propusnošću, tj. uz pomoć simulacije strujnica unutar makromodela s diskontinuitetima

Diagnostic Accuracy of CT Scan for Detection of Cervical Lymph Node Metastasis in Oral Squamous Cell Carcinoma in Comparison with Histopathological Analysis After Neck Dissection

Objectives: Presence/absence of cervical lymph node metastasis plays a critical role in prognosis and survival of patients with oral squamous cell carcinoma (SCC). This study was designed to assess the diagnostic accuracy of computed tomography (CT) scan for detection of cervical lymph node metastasis in oral SCC in comparison with histopathological analysis after neck dissection.Methods: In this retrospective cross-sectional study, pathology and CT reports of 50 patients with oral SCC were retrieved from the archives of Taleghani and Shariati Hospitals and data regarding the site of involvement, lymph node metastasis, level of cervical involvement and size of involved lymph node were retrieved from patient files. The results of CT scan and pathology reports were compared and the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CT scan were calculated compared to the gold standard (pathology report). Basic statistics was meed for analyz the data.Results: The sensitivity of CT scan for detection of metastatic cervical lymph nodes was 69.23% compared to the pathology report (gold standard). The specificity, PPV and NPV were 27.02%, 25% and 71.42%, respectively. The diagnostic accuracy of CT scan was 38%.Conclusion: Based on the results, CT scan is not reliable for detection of metastatic cervical lymph nodes in oral SCC, and more advanced techniques may be indicated for assessment of cervical lymph node involvement and deciding on the most efficient surgical approach in patients with oral SCC

Comparing the Effectiveness of Acceptance and Commitment Therapy (ACT), Drug Therapy, and the Combination of These Two Methods in the Treatment of Major Depression

Introduction: A large number of people are afflicted with major depressive disorder, leading to high societal costs. In addition, the treatment remains one of the most challenging and controversial issues in mental health. The main purpose of this study is to compare the effectiveness of acceptance and commitment therapy (ACT), pharmacotherapy, and a blend of the two methods in treating major depressive disorder. Methods: A sample of 60 subjects was selected randomly from the middle-aged patients suffering from major depressive disorder (based on DSM-V criteria) with illness duration of one year that referred to all outpatient clinics of the Modares hospital in Isfahan. The patients were divided into four experimental groups including: acceptance and commitment therapy (ACT), Drug Therapy, blend of the two aforementioned methods and control group. Statistical analysis was conducted using analysis of covariance. Results: Findings showed a significant difference in terms of depression among the three treatment groups. While the mean scores of depression in the posttest were 44.60 for the control group, the results for pharmacotherapy, ACT and combination group were 17.66, 26.53 and 15.13 respectively (p˂0.05). Discussion: Although, Pharmacotherapy and combined treatment are more effective than ACT alone, the combination of ACT and pharmacotherapy is the most effective with longer-lasting results in the treatment of adults with major depressive disorder in middle-aged Iranian patients. Declaration of Interest: None

Analysis of longitudinal binary outcomes in clinical trials with low percentage of missing values

In interventional or observational longitudinal studies, the issue of missing values is one of the main concepts that should be investigated. The researcher's main concerns are the impact of missing data on the final results of the study and the appropriate methods that missing values should be handled. Regarding the role and the scale of the variable that missing values have been occurred and the structure of missing values, different methods for analysis have been presented. In this article, the impact of missing values on a binary response variable, in a longitudinal clinical trial with three follow up sessions has been investigated Propensity Score, Predictive Model Based and Mahalanobis imputation strategies with complete case and available data methods have been used for dealing with missing values in the mentioned study. Three models; Random intercept, Marginal GEE and Marginalized Random effects models were implemented to evaluate the effect of covariates. The percentage of missing responses in each of the treatment groups, throughout the course of the study, differs from 6.8 to 14.1. Although, the estimate of variance component in random intercept and marginalized random effect models were highly significant (p <0.001) the same results were obtained for the effect of independent variables on the response variable with different imputation strategies. In our study according to the low missing percentage, there were no considerable differences between different methods that were used for handling missing data

Lithium-ion battery prognostics through reinforcement learning based on entropy measures

Lithium-ion is a progressive battery technology that has vastly been used in different electrical systems. Failure in the battery can lead to failure in the entire system where the battery is embedded and cause irreversible damage. To avoid the probable damages, research is actively conducted, and data-driven methods are proposed based on prognostics and health management (PHM) systems. PHM can use multiple time-scale data and stored information from battery capacities over cycles to determine the battery state of health (SOH) and its remaining useful life (RUL). This results in battery safety, stability, reliability, and longer lifetime. In this paper, we propose different data-driven approaches to battery prognostics that rely on: Long Short-Term Memory (LSTM), Autoregressive Integrated Moving Average (ARIMA) and Reinforcement Learning (RL) based on the Permutation Entropy of battery voltage sequences at each cycle since they take into account the vital information from the past data and result in high accuracy

Late clinical events of drug eluting versus bare metal stenting; OPCES' ancillary study

Objective: To compare one year clinical outcomes of patients with chronic stable angina who underwent implantation of bare metal stent (BMS) or drug eluting stent (DES). Methodology: Four hundred forty two (442) participants of OPCES study (Osvix versus Plavix in Cardiovascular Events after Stenting) were included in this sub-study. After evaluation of exclusion criteria (combined DES and BMS stenting (n=31) and incomplete data (n=48) patients were divided in two groups according to selected stent(DES or BMS). Follow-up was conducted by a structured telephone interview after 6 and 12 months. The patients' documents were reviewed by the Study Event Committee in the Isfahan Cardiovascular Research Center to evaluate the occurrence of study endpoints which consisted of clinical success rate and major adverse cardiac events (Major Adverse Cardiac Events (MACE), cardiac death, non-fatal MI, target vessel revascularization and stroke) in hospital, after 6 and 12 months. Results: One hundred sixty six (45.7%) patients were in the DES and 197(54.3%) were in the BMS group. Procedural complications were seen more frequently in the DES group (1.0% vs. 4.8%, P=0.027), the prevalence of the in-hospital MACE, angiographic and clinical success rate were the same between both the groups. There was no significant difference regarding 6 and 12 months MACE rate in patients treated by BMS or DES (6 months: 1.1% vs. 0.6%, p>0.999 12 month: 3.4% vs 2.6%, P = 0.755). Conclusion: Considering the same clinical outcome and the economical parameters, use of the BMS after proper patient selection are recommended

A multilayer feedforward perceptron model in neural networks for predicting stock market short-term trends

Stock market prediction is important for investors seeking a return on the capital invested, though this prediction is a challenging task, due to the complexity of stock price time-series. This task can be performed by conducting two primary analyses: fundamental and technical. In this paper, we examine the predictability of these two analyses using a Multilayer Feedforward Perceptron Neural Network (MLP) and determine whether MLP is capable of accurately predicting stock market short-term trends. We utilize stock prices (2013/03 – 2018/06) and twelve financial ratios of Technology companies selected through a feature selection preprocess. Our model uses Self-Organizing Maps (SOM) for clustering the historical prices and produces a low-dimensional discretized representation of the input space. The best results are obtained through hyper-parameter optimizations using a three-hidden layer MLP. The models are integrated using a Nonlinear Autoregressive structure with Exogenous Input (NARX). We find that the hybrid model successfully predicts the short-term stock trends. The hybrid model yields the greatest directional accuracy (70.36%) as compared to fundamental and technical analyses (64.38% and 62.85%) and state-of-the-art models. The results indicate that the market is not fully efficient. Our model will be useful to practitioners seeking investing and trading opportunities, and others interested in the study of financial markets

Influence of coping and veneer thickness on the color of zirconia-based restorations on different implant abutment backgrounds

Statement of problem: The effects of coping and veneer thickness on the color of zirconia-based restorations are unknown. Purpose: The purpose of this in vitro study was to evaluate the influence of coping and veneer thickness on the color of zirconia-based restorations on different implant abutment backgrounds and to define minimum coping and veneer thicknesses for the backgrounds investigated to achieve a target color. Material and methods: Thirty zirconia disk specimens with thicknesses of 0.4, 0.6, and 0.8 mm and 30 veneering ceramic disk specimens with thicknesses of 0.8, 1.0, and 1.2 mm were fabricated. Three backgrounds were prepared: titanium alloy, zirconia ceramic, and base metal alloy. The zirconia specimens were placed on the backgrounds, and the veneering ceramic specimens were located on the zirconia specimens. Spectrophotometric measurements were made to determine CIELab values. Color difference (ΔE) values were calculated to measure color differences between the specimens and the A2 VITA classical shade tab. ΔE values were compared with a perceptibility threshold (ΔE=2.6). Repeated measures ANOVA, Bonferroni test, and 1-sample t test were used to analyze data (α=.05). Results: Mean ΔE values ranged from 2.0 to 9.8. Coping thickness, veneer thickness, and their combination significantly affected ΔE (P<.001). Conclusions: To achieve the target color with zirconia-based restorations, regardless of the backgrounds tested, the minimum thickness of zirconia coping should be 0.6 mm, and the minimum thickness of veneering ceramic should be 1.2 mm

Information sharing systems and teamwork between sub-teams: a mathematical modeling perspective

Abstract Teamwork contributes to a considerable improvement in quality and quantity of the ultimate outcome. Collaboration and alliance between team members bring a substantial progress for any business. However, it is imperative to acquire an appropriate team since many factors must be considered in this regard. Team size may represent the effectiveness of a team and it is of paramount importance to determine what the ideal team size exactly should be. In addition, information technology increasingly plays a differentiating role in productivity and adopting appropriate information sharing systems may contribute to improvement in efficiency especially in competitive markets when there are numerous producers that compete with each other. The significance of transmitting information to individuals is inevitable to assure an improvement in team performance. In this paper, a model of teamwork and its organizational structure are presented. Furthermore, a mathematical model is proposed in order to characterize a group of sub-teams according to two criteria: team size and information technology. The effect of information technology on performance of team and sub-teams as well as optimum size of those team and sub-teams from a productivity perspective are studied. Moreover, a quantitative sensitivity analysis is presented in order to analyze the interaction between these two factors through a sharing system

Assessment of Sound Loudness Using Self-Assessment Profile of Aided Loudness (PAL) Questionnaire in Young Individuals and Elderlies with Moderate and Severe Hearing Loss Using Hearing Aid

Introduction: Common audiometric tests can assess if there is any hearing injury or not, but they can not assess the impact of disability due to hearing loss, individual's satisfaction level from rehabilitation services, and the impact of disability on life, due to hearing loss. These items can be assessed using self-assessment questionnaires. This study aimed to use self-assessment Profile of Aided Loudness (PAL) questionnaire to compare satisfaction and loudness levels of sounds in young individuals and elderlies with moderate and severe hearing loss using hearing aid. Materials and Methods: In this cross-sectional study, 20 young individuals with age range of 20 to 40 years and 20 elderlies with age range from 60 to 80 years were enrolled. Satisfaction and sound loudness levels of the hearing aid were assessed using self-assessment PAL questionnaire. Data were collected and analyzed using computer statistical information analysis software. Results: Loudness level had no significant differences among young individuals and elderlies, and women and men. Loudness level had no significant differences for soft sounds, but for average and loud sounds, the differences were significant. Satisfaction levels did not show any significant differences between moderate and severe hearing loss, and between women and men; but the difference between young individuals and elderlies was significant. Conclusion: PAL index is efficient to assess the understood sound loudness in an individual with and without hearing aid. Comparing the outcomes of this questionnaire with normal levels is used to select and adjust the hearing aid. The results of this study show that loudness understanding is affected by the level of hearing loss, and satisfaction level is affected by age factor