فهرست مطالب ali tavakoligolpaygani

Uncertainty evaluation is an important task in almost all activities in the field of calibration and standard conformity assessment. Evaluation of uncertainty is a process in which the statistical characteristics (mainly the first and second moments; i.e. the average and the standard deviation) of the result of a measurement are estimated based on those of contributing factors. The result of this process is used to determine how appropriate a measurement is for a specific application. The measurement uncertainty influences the result of binary decisions made on conformity assessment, calibration and many other applications in the fields of jurisdiction, commerce, law enforcement or healthcare. Another important application of uncertainty evaluation, is to evaluate and validate mathematical or computer models simulating real world phenomena. For example, an uncertainty evaluation process can be utilized to quantify the error characteristics of a simulation software. Many techniques have been introduced and practiced for uncertainty evaluation. The applicability of each method relies upon the measurement model, possibility of performing repeated simulations and availability of statistical data. In this paper, we examine a celebrated uncertainty propagation method, namely; the Polynomial Chaos Expansion in the uncertainty evaluation of measurements described by a rigorous mathematical model. These measurement processes have been conventionally studied using sensitivity coefficients which can be calculated via partial derivatives. The two approaches are compared in an illustrative example.

Medical devices play a pivotal role in modern healthcare, contributing to improved patient outcomes and enhanced quality of life. However, with their growing complexity and integration into various medical practices, there is a pressing need to address potential risks associated with their use. This implies that the device should be safe and effective and risk analysis plays a key role in the development of medical devices design. The goal is to minimize related use hazards and, assure the final users are able to use medical devices safely and effectively throughout the product life cycle.By identifying and addressing potential risks throughout the device's lifecycle, stakeholders can collectively work towards the goal of providing safer and more effective medical devices for the betterment of healthcare worldwide.This note highlights the significance of risk management in the medical device industry and explores how effective risk management strategies can ensure the safety and efficacy of medical devices, ultimately benefiting both patients and healthcare provider.

Keratoconus is a non-inflammatory ocular disorder in which the cornea bulges in the shape of a cone. Therefore, this progressive disease will cause visual impairment. The precise aetiology of keratoconus is not well understood. Investigating the pathogenesis of keratoconus from a biomechanical point of view will determine which biomechanical factor plays the dominant role in keratoconus formation. In this study, using the finite element method, a three-dimensional model of the human cornea with anatomical dimensions was created, and hyperelastic isotropic properties were assigned to it. Then, the inner surfaces of the model were subjected to physiological intraocular pressure. This model was regarded as a healthy cornea and as a reference model. Then, two symmetric and asymmetric states of keratoconus were simulated. For this purpose, a circular region was created in the center of the cornea (for the symmetric state) or in one of its quarters (for the asymmetric state), and then, in this circular region (i.e., locally), the following operations were performed with three different intensities to simulate three different stages of symmetric/asymmetric keratoconus: 1) reducing the thickness, 2) weakening the mechanical properties, and 3) reducing the thickness and weakening the mechanical properties, simultaneously. By analyzing the displacements, it was found that the local weakening of the mechanical properties makes the cornea significantly steep in the area affected by the disease and causes keratoconus formation. Therefore, in keratoconus formation, the weakening of mechanical properties plays a primary role, and the reduction of thickness plays a secondary and auxiliary role.

Nowadays, based on the spreading of information technology, food consumers especially organic food increasingly want to be informed about the history of food products that they are buying. They want to know about the origin of food, the condition of storage, transporting, etc. besides the information are printed on the packages. In this paper, we are proposing a back and forth supervision system on organic products supply chain based on blockchain technology to ensure data integrity and allow data tracing. The proposed system as a decentralized and secure infrastructure database improves food security and safety, and reduces fraud by verifying the quality and the origin of the products throughout the entire their agricultural supply chain. A unique Quick Response code was used to identify each product within the supply chain. Automated protocols on validation each transaction and events related to a product by peers of the Blockchain system enable data transmitted on the network to be verified and stored immutably and minimizing the risk of data corruption.

Nowadays, based on the spreading of information technology, food consumers especially organic food increasingly want to be informed about the history of food products that they are buying. They want to know about the origin of food, the condition of storage, transporting, etc. besides the information are printed on the packages. In this paper, we are proposing a back and forth supervision system on organic products supply chain based on blockchain technology to ensure data integrity and allow data tracing. The proposed system as a decentralized and secure infrastructure database improves food security and safety, and reduces fraud by verifying the quality and the origin of the products throughout the entire their agricultural supply chain. A unique Quick Response code was used to identify each product within the supply chain. Automated protocols on validation each transaction and events related to a product by peers of the Blockchain system enable data transmitted on the network to be verified and stored immutably and minimizing the risk of data corruption.

Micromixing has a practical application in analyzing of many biochemical and biologicals detection devices of lab-on-a-chip (LOC). The conventional static micromixers require the channel with more lengths and also require times to reach to complete mixing owing to its dependence on transverse diffusion. However, in the electrokinetic micromixers, as the surface properties of the microchannel run the electro-osmotic flow characteristics, surface heterogeneity (non-uniform zeta potentials) can be seen to make vortices or specific flow structures for better mixing performance. This study aims to use computational fluid dynamics (CFD) to numerically compare the concentration rate of the various electrokinetic micromixers in in the presence of the electric conductor. The results revealed that the off-center microchannel design in a micromixer can augment the rate of concentration. In addition, circular microchannel design showed better mixing compared to the triangular and square designs. These results are useful not only for understanding of the profiles of concentration in the electrokinetic micromixers, but also for providing a comprehensive information on the design of the microchannels, which may result in better mixture in the fluids

Today’s, more than 10000 types of different medical devices are currently employed in medium and large hospitals. These devices have an important role in the diagnosis, treatment, and monitoring processes in health centers. An efficient preventative maintenance program of these devices is essential to guarantee the correct functioning and ensure the safe and reliable operation of them. As the maintenance activities increase as increasing the variety of medical devices, the need for a better maintenance management system become more essential than the past. In this paper a new multi-criteria decision-making approach of system engineering to lifecycle management and preventive maintenance priority of medical devices based on a kind of quality function deployment is presented. The model was implemented and tested in three public hospitals in one of the western provinces of Iran. None of the three hospitals had established a proper assessment management program processes to identify their equipment needs and required maintenance priority based on their annual budgets. Our suggested model solved one of the big decision problems in their management system, the results helped them to have a priority list of the medical devices that should be replaced and the preventative maintenance priority of critical devices based on the wards, type and number of them according to the available budget. Implementation of our proposed model in medical centers can maximize the reliability of equipment and systems among the limitation of organizational resources and budgets

International competitiveness is the key to Iran’s participation in global trade. Iran’s success in achieving the goals of economic diversification and trade competitiveness will correlate highly with the coherence of its national quality infrastructure. A well-functioning quality infrastructure in Iran that helps firms in priority sectors meet the requirements of export markets and supports them in demonstrating conformity with the requirements in a holistic manner, will act as a catalyst to improve the competitiveness of Iran’s economy, its ability to participate in global trade and increase the value of trade.The aim of this study is to introduce the Iran National Quality Infrastructure (NQI) and its position in the Global Quality Infrastructure Index (GQII) programme. The GQII plays as a good indicator to measure the growth and the performance of QI of any economy. It provides valuable data that can be used for different types of analysis by QI body representatives, policymakers and other leaders to informed business decisions making.In this paper, first, the concept and overall framework of a national quality system is mentioned; then the Iran NQI system framework is explained in detail. Finally, based on the International ranking of Iran in GQII, strengths and weaknesses of the Iran NQI system are pointed and the possible solutions for improvement on the overall construction and each element of it are proposed. The study would be very helpful for the government agencies, industry, academia, and enterprises for future decisions and policymaking related to strong and robust QI.

Nowadays, medical implants are widely used around the world. Medical implant device safety is closely related to public health and national security. With all the governmental considerations, issues such as selling or distributing an unapproved, defective, or expired implant and record fraud are still widespread in medical device supply chains. Blockchain, the next generation of information technology, is designed to provide better trust and transparency in information management systems.  This paper presents the development of a “Medical Implant blockchain” system based on blockchain technology. This system can provide good traceability and transparency throughout the value chains of implants in a national supply chain. This study provides evidence for the necessity of a blockchain system development for the medical implants supply chain to increase trust and equity between various stakeholders. It shows that legal organizations can create a safe and reliable trading environment by using an information management system based on blockchain technology. Implementing a blockchain medical implants management system enables verified information transmission and immutably data storage on the network. This system could provide valuable information with higher transparency by minimizing the risk of data corruption for all the beneficiaries, such as legal authorities, medical centers, specialists, and patients.

Nowadays, medical implants are widely used in treating, monitoring, and restoring limb function. These implants are made of biocompatible artificial materials and are planted in patients’ bodies for medical purposes usually for a long time. One reason for the boost in the applications of these devices is the increase in the elderly population given the rise in life expectancy, especially in developed countries. Implantation of fake implant can cause infection and pain in the patient who use the implant. Therefore, the existence of a reliable supply chain is necessary. Blockchain is a good candidate as a platform for supply chain. blockchain transactions are irreversible in that, once they are recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks. Also register of new information should be done conditionally by nodes consensus, so the trustworthiness can be improved. The aim of this study is to develop a “Medical Implants Blockchain” as a national tracking supply chain system based on blockchain technology. This system is designed to support medical implants traceability and can be used to address the problems of implants expiration and record fraud. Registering and monitoring medical implants in an integrated system plays a key role in improving consumer safety. The system could provide valuable information for various levels of users, such as supervisory bodies, manufacturers, and consumers. Based upon blockchain information, design of a secure recommender system with preserving privacy is possible.

Hemodialysis serves as a therapy for patients with kidney malfunction. Kidney malfunction results in the accumulation of toxins and excess fluid in the body, leading to the patient’s death if not removed. Hemodialysis adequacy can be quantified by analyzing dialysate conductivity at the dialyzer inlet and outlet.

In this paper, the authors presented a non-invasive and low-cost monitoring system of hemodialysis adequacy, which can continuously measure the conductivity of soluble in dialysis machines, allowing the delivery of more acceptable treatment.

An online measurement indicated that the presented system could easily show ionic dialysance and the patient's plasma conductivity at two different parts of the dialysate route. This technique can be an effective way to decide about terminating the dialysis according to plasma sodium concentration. The proposed system can be used as an easy-to-use impedance spectroscopy system to measure the patient's plasma conductivity on a dialysis machine. The designed system was tested and validated experimentally in actual dialysis sessions. This technique does not require any disposables or reagents, reducing patient anxiety and cost by decreasing blood sampling and laboratory analysis.

The operation and development of this system on dialysis machines will effectively prevent dialysis-induced complications.

Artificial intelligence plays an important role in medicine. Specially, expert systems can be designed for diagnosis of disease. Artificial intelligence can be used for diagnosis of disease. This study proposes an expert system for diagnosis of Multiple Sclerosis based on clinical symptoms and demographic characteristics. Specially, it recommends patients to refer to a specialist for further investigation. In this empirical study, some symptoms of Multiple Sclerosis are mapped to fuzzy sets. Moreover, several rules are defined for prediction of Multiple Sclerosis. The fuzzy sets and rules form the knowledge base of the expert system. Patients enter their symptoms and demographic information via a user interface and Mamdani method is used in inference engine to produce the appropriate recommendation. The precision, recall, and F-measure are used as criteria to analyze the efficiency of the expert system. The results show that the designed expert system can recommend patients for further investigation as effective as specialists. Specially, while the proposed expert system recommended referring to a doctor for some healthy users, most of the MS patients are diagnosed. The proposed expert system in this study can analyze the symptoms of patients to predict the Multiple Sclerosis disease. Therefore, it can investigate initial status of patients in a rapid and cost-effective manner. Moreover, this system can be applied in situations and places, which human experts are unavailable.

A medical device is any instrument, apparatus, implement, machine, appliance, software, material, which is intended material, to be utilized, either alone or in combination, for medical purpose. These devices should work precisely and the maintenance program of them has also a key role to achieve this goal. Many of the maintenance programs have not considered important functional parameters such as equipment type, risk factors, and expert opinion.

The purpose of this study is to present a novel fuzzy method for medical device risk assessment. The obtained values for risk could be used to prioritize maintenance operations by considering allocation budget.

This experimental study aims to make a new application of Ordered-Weighted Average operator in aggregation of different parameters for calculating Risk Priority Number. This model is a fuzzy multi-criteria decision making approach based on risk maintenance framework for medical device prioritization.

A limited budget is one of the barrier in medical centers. The suggested framework presents a simple and reliable method to choose the best maintenance strategy for each kind of medical device by considering budget limitation. Based on obtained results from numerical model, defibrillators and surgical suction have respectively the highest and the lowest priority in mentioned example.

Risk prioritization of medical devices is valuable because the medical centers can prioritize maintenance operations and thereby to establish preference of maintenance strategy. Implementation of our proposed maintenance program has many effective results in medical center budgets.

Breast cancer is the second cause of death among women. Ultrasound (US) imaging is the most common technique for diagnosing breast cancer; however, detecting breast lesions in US images is a difficult task, mainly, because it provides low-quality images. Consequently, identifying lesions in US images is still a challenging task and an open problem in US image processing. This study aims to develop an automated system for the identification of lesions in US images

We proposed an automatic method to assist radiologists in inspecting and analyzing US images in breast screening and diagnosing breast cancer. In contrast to previous research, this work focuses on fusing information extracted from different frames. The developed method consists of template matching, morphological features extraction, local binary patterns, fuzzy C-means clustering, region growing, and information fusion-based image segmentation technique. The performance of the system was evaluated using a database composed of 22 US videos where 10 breast US films were obtained from patients with breast lesions and 12 videos belonged to normal cases.

The sensitivity, specificity, and accuracy of the system in detecting frames with breast lesions were 95.7%, 97.1%, and 97.1%, respectively. The algorithm reduced the vibration of the physician’s hands’ while probing by assessing every 10 frames regardless of the results of the prior frame; hence, lowering the possibility of missing a lesion during an examination.

The presented system outperforms several existing methods in correctly detecting breast lesions in a breast cancer screening test. Fusing information that exists in frames of a breast US film can help improve the identification of lesions (suspect regions) in a screening test.

Sudden cardiac arrest and heart diseases are the leading causes of death globally, but cardiopulmonary resuscitation (CPR) may prevent multitude of death if being performed timely and accurately. Since in many cases of cardiac arrest there is not a trained rescuer and conventional CPR method is difficult and may being performed incorrectly, various equipment has been produced for this purpose. In this study, by reviewing of previous important studies on automated chest compression devices and comparing their effectiveness in returning of spontaneous circulation (ROSC), a novel, portable, programmable, flexible and automated chest compression system is introduced. For prototyping of this device, first required data were extracted from studies on CPR, then mechanical components for compression system and chassis, and electronic components for controlling unit were designed and produced. The novel device which is developed in this research could be installed easily and perform the chest compression according to the patient’s condition and guidelines automatically. It also enables chest compression even during patient transport. Furthermore, because of user-friendly design, everybody could use it easily. Eventually comparison between this device and other similar automated devices indicates that this device has more benefits and more reasonable price as well.

The risk effect of long-term occupational exposure to extremely low-frequencyelectromagnetic fields (ELF-EMFs) has been studied extensively. However,due to several experimental issues such as exposure measurement error and thelack of standard ELF-EMFs exposing devices, the obtained results are controversial.The inconsistent reported results preclude clear conclusions on the evidenceof an association between EMF exposure and the disorders reported. To assist withresolving these issues, a digital–low cost ELF-EMFs generator to produce EMFswith desired magnitude and frequency is proposed. A sinusoidal waveform with adjustable amplitude and frequency controlledby a microprocessor is generated and then is applied to a coil with a U-shapecore. To increase the accuracy of the instrument, three coils with 250 turns; 500turns; and 1200 turns were designed and used in the instrument. The amplitude andfrequency of the voltage delivered to each of these coil are controlled by turningoff and on TRIAC transistors controlled by a microprocessor–based system. The designed instrument provided EMF with magnitude of 0.55 mTeslato 1.56 mTesla with error rate < 5.9% and frequency of 10 Hz to 50 Hz with errorrate <1%. The provided EMF was sufficiently homogeneous over a given volumeand was stable over time. The quantitative and qualitative experimental results showed that the designedinstrument is reliable and accurate to be used in research laboratories for furtherinvestigation of the health effect of long-term occupational exposure to ELF-EMFs.

There is considerable evidence that vascular fluid dynamics plays an important role in the development and prevalence of atherosclerosis which is one of the most widespread disease in humans. The onset and prevalence of atherosclerosis hemodynamic parameter are largely affected by geometric parameters. If any obstacle interferes with the blood flow, the above parameters change dramatically. Most of the arterial diseases, such as atherosclerosis, occur in the arteries with complex patterns of fluid flow where the blood dynamics plays an important role. Arterial stenosis mostly occurs in an area with a complex pattern of fluid flow, such as coronary artery, aorta bifurcation, carotid and vessels of lower limbs. During the past three decades, many experimental studies have been performed on the hemodynamic role of the blood in forming sediment in the inner wall of the vessels. It has been shown that forming sediment in the inner wall of vessels depends on the velocity of fluid and also on the amount of wall shear stress. We have examined the effect on the blood flow of local stenosis in carotid artery in numerical form using the incompressible Navier-Stockes equations. The profile of the velocity in different parts and times in the pulsatile cycle, separation and reattachment points on the wall, the distance stability of flow and also alteration caused by the wall shear stress in entire vessel were shown and compared with two behaviors flow (Newtonian and Non-Newtonian).Finally we describe the influence of the severity of the stenosis on the separation and reattachment points for a Non-Newtonian fuid. In the present study, we have pointed very low and high oscillating WSS (Wall Shear Stress) values play a significant role in the development of forming sediment in the inner wall of vessels. Also, we obtain this probability is higher for Newtonian than Non-Newtonian fluid behavior. Based on our results, the possibility of the endothelium destruction is greater with the Newtonian fluid behavior and in the regions where WSS are beyond the range of 10-420 dyne/cm2.