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Issue Info: 
  • Year: 

    1383
  • Volume: 

    7
Measures: 
  • Views: 

    305
  • Downloads: 

    0
Abstract: 

پیشرفت روزافزون کامپیوترها و متعاقب آن توسعه نرم افزارهای طراحی صنعتی پروسه طاقت فرسای طراحی و ساخت ادوات و ماشین آلات حتی پیچیده را سهل و آسان نموده و با ایجاد فضائی قرین با واقعیت به مهندسین طراح امکان نگرش جامع بر ساخت و عملکرد ماشین آلات را پیش از آنکه عمل شکل دهی، ساخت و بهره برداری آنها به واقع آغاز گردد، فراهم می نماید.انتقال مواد در مراکز صنعتی بخش قابل ملاحظه ای از فعالیتهای روزمره را در بر می گیرد. طراحی و ساخت یک نمونه ماشین انتقال بار TRANSFER car با قابلیت جابجائی بر روی ریل در پروسه ساخت یک واحد صنعتی مد نظر بوده است. این عمل با تهیه مدل کامپیوتری و با استفاده از نرم افزارهای Solid Works، Cosmos Works و Design Star انجام شده است. انتخاب مواد و پروفیل فلزات مورد نیاز منطبق با محصولات موجود در بازارهای داخلی انجام پذیرفته و نتایج بر اساس استاندارد طراحی DIN تنظیم شده اند. همچنین معیارهای متداول در طراحی برای کنترل پروژه و حصول ضرایب اطمینان مناسب مورد استفاده قرار گرفته اند. طرح نهائی پس از گذراندن آزمونهای ضروری، تحت پروسه های لازم برای ساخت قرار گرفته است.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2023
  • Volume: 

    53
  • Issue: 

    1
  • Pages: 

    61-67
Measures: 
  • Citations: 

    0
  • Views: 

    173
  • Downloads: 

    31
Abstract: 

Face recognition from digital images is used for surveillance and authentication in cities, organizations, and personal devices. Internet of Things (IoT)-powered face recognition systems use multiple sensors and one or more servers to process data. All sensor data from initial methods was sent to the central server for processing, raising concerns about sensitive data disclosure. The main concern was that all data from all sectors that could contain confidential information was placed in a central server. Federated learning can solve this problem by using several local model training servers for each region and a central aggregation server to form a global model in IoT networks. This article presents a novel approach to optimize data TRANSFER and convergence time in federated learning for a face recognition task using Non-dominated Sorting Genetic Algorithm II (NSGA II). The aim of the study is to balance the trade-off between training time and model accuracy in a federated learning environment. The results demonstrate the effectiveness of the proposed approach in reducing data TRANSFER and convergence time, leading to improved performance in face recognition accuracy. This research provides insights for researchers and practitioners to enhance the efficiency of federated learning in real-world applications.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    0
  • Volume: 

    29
  • Issue: 

    2
  • Pages: 

    117-121
Measures: 
  • Citations: 

    3
  • Views: 

    1154
  • Downloads: 

    0
Abstract: 

"عامل اثرگذار" واژه ای آشنا برای اغلب جامعه علمی و پزشکی است، ولی با وجود استفاده گسترده و اغلب وسواسی، معدودی بطور کامل معنی یا کاربردهای آن در واقع مجادله های راجع به آن را درک می کنند. در این مقاله نحوه اندازه گیری و استخراج این شاخص موثر و برخی مسایل مربوط به آن (بویژه سو استفاده از آن به عنوان سنجشی از شایستگی نویسنده) بررسی می شود.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2022
  • Volume: 

    12
  • Issue: 

    47
  • Pages: 

    7-32
Measures: 
  • Citations: 

    0
  • Views: 

    186
  • Downloads: 

    39
Abstract: 

Nowadays, the fundamental role of having a purpose for life in physical and mental health has been confirmed. According to victor frankl, presence of a purpose in life gives life a meaning and increases resilience against pains and traumas. The importance of the purpose in life construct reveals the need for a reliable and valid tool to measure it. Crumbaugh and Maholick's purpose in life questionnaire is the first and one of the most applied tools for the assessment of life's purposefulness. The aim of this research is to determine the FACTOR structure of purpose in life questionnaire. The questionnaire was administered on 206 students who were selected through random stratified sampling at Ferdowsi University of Mashhad. Exploratory FACTOR analysis showed that there are two FACTORs "comprehension" and "purpose" and this finding were confirmed by confirmatory FACTOR analysis. Altogether results of this research showed FACTOR validity of the purpose in life questionnaire with a two FACTOR pattern

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2022
  • Volume: 

    52
  • Issue: 

    4
  • Pages: 

    281-291
Measures: 
  • Citations: 

    0
  • Views: 

    158
  • Downloads: 

    18
Abstract: 

Automatic topic detection seems unavoidable in social media analysis due to big text data which their users generate. Clustering-based methods are one of the most important and up-to-date categories in topic detection. The goal of this research is to have a wide study on this category. Therefore, this paper aims to study the main components of clustering-based-topic-detection, which are embedding methods, distance metrics, and clustering algorithms. TRANSFER learning and consequently pretrained language models and word embeddings have been considered in recent years. Regarding the importance of embedding methods, the efficiency of five new embedding methods, from earlier to recent ones, are compared in this paper. To conduct our study, two commonly used distance metrics, in addition to five important clustering algorithms in the field of topic detection, are implemented by the authors. As COVID-19 has turned into a hot trending topic on social networks in recent years, a dataset including one-month tweets collected with COVID-19-related hashtags is used for this study. More than 7500 experiments are performed to determine tunable parameters. Then all combinations of embedding methods, distance metrics and clustering algorithms (50 combinations) are evaluated using Silhouette metric. Results show that T5 strongly outperforms other embedding methods, cosine distance is weakly better than other distance metrics, and DBSCAN is superior to other clustering algorithms.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

Issue Info: 
  • Year: 

    2022
  • Volume: 

    39
  • Issue: 

    -
  • Pages: 

    1373-1381
Measures: 
  • Citations: 

    1
  • Views: 

    23
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • End Date: 

    دی 1386
Measures: 
  • Citations: 

    2
  • Views: 

    293
  • Downloads: 

    0
Keywords: 
Abstract: 

احراز هویت دوگانه به روز ترین روش تامین امنیت دسترسی به منابع شبکه می باشد. این روش در عین سادگی و کم هزینه بودن، امنیت دسترسی به منابع رایانه ای را تا حد قابل توجهی افزایش می دهد. این طرح راهکاری را ارائه خواهد داد که با بهره گیری از مزایای احراز هویت دوگانه روشی مقرون به صرفه جهت پیاده سازی انبوه این نوع از احراز هویت در سطح کشور ارائه خواهد کرد. از آنجایی که بیش از90 درصد از سیستم های احراز هویت در داخل و حتی خارج از کشور بر مبنای کلمات عبور ثابت، قابل استفاده مجدد و قابل حدس مورد استفاده قرار می گیرند که این مساله خود بزرگترین مشکل امنیتی در مورد آنها تلقی می شود. به دیگر سخن، با افزایش امنیت تمامی بخش های جانبی مرتبط با فرآیند احراز هویت نیز نمی توان این ضعف ذاتی سیستم های سنتی را نادیده انگاشت. در این پروژه مطالعات اولیه روی روش های احراز هویت دوگانه انجام و یکی از این روش ها به صورت نرم افزاری پیاده سازی گردید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

Sabohi Z. | Razmjooei M.

Issue Info: 
  • Year: 

    2021
  • Volume: 

    5
  • Issue: 

    1
  • Pages: 

    15-28
Measures: 
  • Citations: 

    0
  • Views: 

    71
  • Downloads: 

    14
Abstract: 

This paper investigates the heat TRANSFERs and ablation of thermal insulators used in motors and nozzles. The heat and mass TRANSFER equations are considered in two dimensions in a convergent-divergent nozzle. The finite volume method and the implicit method for time dependence have been used to solve these equations. We used the equations finite volume method with implicit formulation for time dependency to solve equations. The reaction equation, which is written in the form of Arrhenius, is solved using the Runge-Kutta method, and the density and the flux of the gas produced at each step are obtained. Also, we represent a model for the rate of recession. The validation of the model is compared with the experimental results in silica-phenolic ablation insulators and shows a good agreement of the simulation results with the experimental observations. After validation of the obtained results. The effect of the blowing correction coefficient has been investigated, the results show that this coefficient is very important for the accurate design of ablation insulators. The blowing correction FACTOR reduces the convection heat TRANSFER coefficient, reduces the surface recession, and thus, reduces the back temperature of the insulation. Therefore, in cases where the thickness of the insulation is significant or the heat of ablation is low. This parameter can be important and affect the final results and thus the final design.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Journal: 

Issue Info: 
  • End Date: 

    بهار 1380
Measures: 
  • Citations: 

    0
  • Views: 

    409
  • Downloads: 

    0
Abstract: 

مطالعه فوق یک مطالعه رتروسکوپتیو بوده که در مرکز تحقیقات ناباروری رویان انجام گرفته است.بیماران منتخب مربوط به آغاز سال 1377 تا اواخر سال 1379 می باشند. گروه Tubal FACTOR به عنوان گروه کنترل برگزیده شده اند. 33 بیمار مبتلا به PCO که قبلا حداقل 6 بار تحریک تخمک گذاری باکلومیفن سیترات قرار گرفته بودند با 76 بیمار مبتلا به نازایی بدلیل عامل لوله ای، از نظر نتایج IVF، مقایسه می شوند. در این مطالعه فقط سیکل اول IVF تحت بررسی قرار گرفته است.جهت استنباط آماری از آزمونهای پارامتری Fisher’s exact test, K2, Anov, T.student و در صورت نیاز از آزمونهای Non parametical (K.W) استفاده شده است.پروتکل انتخابی: long protocol (بوسرلین HMG/)بیماران مبتلا به PCO در این مطالعه دارای متوسط سنی کمتر از (4.2±28.5 در مقابل 5.3±32 روز)، مدت زمان فاز فولیکولی از شروع HMG تا HCG بیشتر (2.8±12.3 در مقابل 3.2±10.9 روز)، بروز OHSS بیشتر (17.6% در مقابل 2.7%) و pregnancy rate/Embryo TRANSFER بیشتری (20% در مقابل 1.4%) نسبت به گروه کنترل می باشند (P<0.05).اما در موارد زیر اختلاف واضحی بین دو گروه وجود ندارد: طول مدت گرفتن GnRHa تا شروع HMG (13.3 در مقابل 12.6)، وجود cyst بعد از دریافت بوسرلین (12.1% در مقابل 23%)، درصد موارد تخلیه cyst (3.03% در مقابل 10.5%)، تعداد آمپول HMG مصرفی (31.8% در مقابل 29.09)، تعداد oocyte بدست آمده (7.6 در مقابل 6.7)، تعداد جنین تشکیل شده در هر فرد (5.1 در مقابل 4.6)، تعداد جنین انتقال یافته در هر نفر (2.7 در مقابل 3.06) و cancel سیکل (0 در مقابل 5.9).در این مطالعه، فرض 1 (برابر بودن میزان P.R/E.T در دو گروه) رد شد و فرض 2 (بیشتر بودن میزان OHSS در گروه PCO نسبت به (Tubal FACTOR تایید گردید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2020
  • Volume: 

    18
  • Issue: 

    1
  • Pages: 

    157-166
Measures: 
  • Citations: 

    0
  • Views: 

    169
  • Downloads: 

    334
Abstract: 

Background: This work investigated the TRANSFER FACTOR of radionuclides from clay loam soil to sesame and cowpea plants. Materials and Methods: Twenty samples from the plant and twenty samples from its soil were collected from five different locations (farms). Gamma-ray spectrometry was used to determine the activity concentration for the samples. In addition, the soil physicochemical characteristics such as pH value, the amount of organic content and texture of soil were investigated by pH meter, Walkley-Black and particle size distribution (Pipette) methods, respectively. Results: The average activity concentrations, respectively, of 226Ra, 232Th, and 40K were 12. 75, 10. 20 and 131. 75 Bq kg-1 for the clay loam soil, 5. 20, 4. 15 and 171. 00 Bq kg-1 for sesame and 6. 70, 5. 60 and 182. 90 Bq kg-1 for cowpea. The TRANSFER FACTOR from soil to sesame and cowpea was discussed. The average values of TRANSFER FACTOR were 0. 51, 0. 53 and 1. 36 (for cowpea) and 0. 42, 0. 43 and 1. 33 (for sesame), respectively for 226Ra, 232Th and 40K. The results showed that the TRANSFER FACTOR in cowpea is much greater than that in sesame. As a result of the ingestion of the radionuclides from the plants, the average annual dose was lower than the 290 μ Sv y-1 world average. Conclusion: Accordingly, the radiological risk due to the intake of the natural radionuclides in these plants was immaterial.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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