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نویسنده: 

Ramazany A. | GHIYASVAND M.

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    5
تعامل: 
  • بازدید: 

    106
  • دانلود: 

    0
چکیده: 

Network virtualization IS AN IMPORTANT CONCEPT TO OVERCOME THE OSSIFICATION OF TODAY’S INTERNET AS IT FACILITATES INNOVATION ALSO IN THE Network CORE AND AS IT PROMISES A MORE EFFICIENT USE OF THE GIVEN RESOURCES AND INFRASTRUCTURE. VIRTUAL NetworkS (VNETS) PROVIDE AN ABSTRACTION OF THE PHYSICAL Network: MULTIPLE VNETS MAY COHABIT THE SAME PHYSICAL Network, BUT CAN BE BASED ON COMPLETELY DIFFERENT PROTOCOL STACKS (ALSO BEYOND IP). ONE OF THE MAIN CHALLENGES IN Network virtualization IS THE EFFICIENT ADMISSION CONTROL AND EMBEDDING OF VNETS. THE DEMAND FOR VIRTUAL NetworkS (E.G., FOR A VIDEO CONFERENCE) CAN BE HARD TO PREDICT, AND ONCE THE REQUEST IS ACCEPTED, THE SPECIFICATION / QOS GUARANTEES MUST BE ENSURED THROUGHOUT THE VNET’S LIFETIME. THIS REQUIRES AN ADMISSION CONTROL ALGORITHM WHICH ONLY SELECTS HIGH-BENEFIT VNETS IN TIMES OF SCARCE RESOURCES, AND AN EMBEDDING ALGORITHM WHICH REALIZES THE VNET IN SUCH A WAY THAT THE LIKELIHOOD THAT FUTURE REQUESTS CAN BE EMBEDDED AS WELL IS MAXIMIZED. IN THIS DOCUMENT, WE SURVEY VARIOUS ALGORITHMS PROPOSED FOR VIRTUAL NetworkS THAT ARE AVAILABLE. WE HERE TRY NOT TO BE EXHAUSTIVE BUT ANALYZE THE IMPORTANT TECHNIQUES IN THE LITERATURE. PRESENT SURVEY WOULD HELP TO GIVE A NEW DIRECTION TO THE RESEARCH IN THIS REALM.

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

بازدید 106

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نویسندگان: 

A. Hammoudeh Mohammad Ali

اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    12
  • شماره: 

    2
  • صفحات: 

    79-89
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    125
  • دانلود: 

    0
چکیده: 

As mobile data traffic increases, and the number of services provided by the mobile Network increases, service load flows as well, which requires changing in the principles, models, and strategies for media transmission streams serving to guarantee the given nature of giving a wide scope of services in Flexible and cost-effective. Right now, the fundamental question remains what number of Network slices will be cost effective for slice managing and giving the required functionality. So, the aim is to improve the efficiency of mobile Network by forming an ideal slice in a multi-service communication Network. In this paper, we propose a model to demonstrate Network resource allocation system that forms devoted Network slices to serve particular types of services independently on shared infrastructure. This model solves the problem of creating a strategy to form multi-service core mobile communication Network slices, which allow the providing of a wide scope of services with certain quality indicators according to the effective dynamic configuration of the system. A resource management system model is created, to provide a method that considers costs related with excessive resource allocation, and also reduces the number of Network recalculations, allowing for a reasonable proportion of management costs and Qualities of Service.

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

بازدید 125

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اطلاعات دوره: 
  • سال: 

    2023
  • دوره: 

    9
تعامل: 
  • بازدید: 

    59
  • دانلود: 

    0
چکیده: 

Denial-of-service attacks are always one of the most widespread security attacks at the enterprise Network level. In DDOS attacks, a large amount of false demand is intentionally sent to the target Network to disable the service. In DDoS attacks, the target server faces many demands, not from a specific source, but from different locations of the attack, which makes detection and defense more difficult. With the introduction of Network functions virtualization and Software-defined Networking, a new route, for Network design and management, has been created. The purpose of this research is to investigate and compare DDoS attack defense methods using NFV and SDN. The details provided will help researchers in this field familiarize themselves with DDoS attack defense methods and choose the appropriate design for their actual implementations.

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

بازدید 59

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    24
  • شماره: 

    63 (مسلسل 95)
  • صفحات: 

    111-139
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    87
  • دانلود: 

    17
چکیده: 

مصرف رسانه های نوین یکی از مهم ترین عرصه های فرهنگی در زندگی روزمره است. گسترش و رواج ارتباطات آنی و پیوسته به سرعت عرصه های مختلف زندگی روزمره را تحت تأثیر قرار داده است. امروزه حضور دائم فناوری های مجازی در محیط های دانشگاهی به سختی قابل انکار است. در این میان، دانشگاه نیز ماهیت و معنای پیشین خود را از دست داده است و همین امر به ویژه سبب تغییر در کارکرد و نسبت دانشگاه شده است. هدف این مقاله، بررسی رابطه بین مجازی شدن کلاس درس و فرهنگ دانشگاهی در دوران کروناست. پارادایم پژوهش کمی و روش تحقیق، پیمایش بوده است. جامعۀ آماری تحقیق، دانشگاه های دولتی شهر تهران در سه دسته دانشگاه حضوری، نیمه حضوری و غیرحضوری است. حجم نمونه تحقیق برابر با 385 نفر می باشد. در این پژوهش ابتدا از نمونه گیری تصادفی خوشه ای و سپس از نمونه گیری احتمالی متناسب با حجم استفاده شده است. مدل پژوهش با استفاده از نرم­افزار لیزرل آزمون شد. نتایج بیانگر آن است که فرایند مجازی شدن از طریق تأثیر بر متغیر ارتباطات به عنوان متغیر میانی بر فرهنگ دانشگاهی و ابعاد آن همچون سبک زندگی، فرهنگ سازمانی و ... تأثیر معناداری دارد. باید گفت، ارتباطات واسطه ای است که بین مجازی شدن و ابعاد مختلف فرهنگ دانشگاهی میانجی گری می کند. آنچه از یافته­ ها برداشت می­شود این است که این فرایند، دگرگونی بنیادینی را در تعاملات و ارتباطات انسانی ایجاد کرده است و این دگرگونی در تعاملات به سایر ابعاد زندگی و فرهنگ دانشگاهی نیز سرایت کرده است.

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

بازدید 87

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 17 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
اطلاعات دوره: 
  • سال: 

    2018
  • دوره: 

    17
  • شماره: 

    39
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    167
  • دانلود: 

    0
چکیده: 

The study is to rank the indicators that affect the sale of sports products through cyberspace from the perspective of physical education students of Payam-e-Noor University of Tehran. The statistical population included all female and male physical education students of Payam-e-Noor University of Tehran, whose total number was 1302 (635 women and 667 men). According to Morgan table, 302 individuals were selected by cluster and random sampling from south Tehran, Tehran west, Lavasan, Shahriar, Varamin and Pakdasht branches. A researcher-made questionnaire was used to collect data. Its validity was confirmed by 10 sport management experts and its reliability was calculated by Cronbach's alpha (0. 81). To assess the validity of the questionnaire, content validity and confirmatory factor analysis were used. This research is an applied survey and its information was provided on gathering method. In order to investigate the relationship between variables, the correlation between the types of research is measured. For data analysis, one-sample t-test and two samples, ANOVA test, Pearson correlation test, and Friedman test for ranking the factors were used by SPSS20 software. Factors such as the quality of content and website design, the amount of Internet access, the method of receiving goods and how to pay, the speed and ease of using the website, the reliability of the store, the side services and its effective advertising are factors affecting the sales of goods. On the other hand, it was found that the age and education are important factors in the attitude of individuals towards the impact of store promotions on its sales growth.

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

بازدید 167

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اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    11
  • شماره: 

    3
  • صفحات: 

    131-137
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    225
  • دانلود: 

    0
چکیده: 

Data virtualization (DV) has become an important method to store and handle data cost-efficiently. However, it is unclear what kind of data and when data should be virtualized or not. We applied a design science approach in the first stage to get a state of the art of DV regarding data integration and to present a concept matrix. We extend the knowledge base with a systematic literature review resulting in 15 critical success factors for DV. Practitioners can use these critical success factors to decide between DV and Extract, Transform, Load (ETL) as data integration approach.

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

بازدید 225

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مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    33-54
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    173
  • دانلود: 

    22
چکیده: 

Improving participation in voluntary activities in Iran is important because increasing productivity among young people, given the country's young population, contributes to community sustainability. Therefore, a better understanding of volunteer motivation in Iranian youth is needed. The Volunteer functions Inventory (VFI) for assessing volunteer motivations has good psychometric properties and is adapted to several languages, but no validated Iranian translation yet exists. The purpose of this study was to investigate the psychometric Characteristics of voluntary functions inventory in members of Iranian Red Crescent Society. Sample size was 595 members of Youth Organization of Iranian Red Crescent Society from 31 provinces and 175 cities of Iran that were selected by multi-stage cluster sampling method and responded to voluntary functions inventory. Data were collected using a demographic sample and voluntary functions inventory (VFI). Confirmatory factor analysis using principal components method was used for data analysis. The results of the present study showed that the voluntary functions inventory had validity and reliability. Also, the factor structure showed that 29 items and 6 factors well assess people's attitudes to volunteering, and the structure of this inventory was well-fitted and confirmed all goodness of fit models. The present study provides the use of the Iranian translation of the Voluntary functions Inventory (6 scales and 29 items) to assess volunteer motivation among young Iranian volunteers.

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

بازدید 173

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نویسندگان: 

فراستخواه مقصود

نشریه: 

برگ فرهنگ

اطلاعات دوره: 
  • سال: 

    1389
  • دوره: 

    جدید
  • شماره: 

    21
  • صفحات: 

    86-102
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1409
  • دانلود: 

    419
کلیدواژه: 
چکیده: 

ظهور محیط های مجازی و غیرحضوری یادگیری، امکانات و آفاق تازه ای برای دسترسی شهروندان جهانی به اطلاعات و کسب دانش فراهم می آورد. این محیط نوپدید، البته پشتگرم به دگرگونی های تکنولوژیک ناشی از انقلاب الکترونیکی دو سه دهه پایانی قرن بیستم بوده است، انقلابی که در قرن بیست و یکم نیز همچنان با شتاب فراوان در حال رشد و بالندگی است. اما عمق وابعاد قضیه بسی ورای سطح فنی و تکنیکی و ظاهری آن است بلکه دگرگونی ژرف و گسترده پارادایمی را در امر یاددهی ویادگیری بازنمایی می کند. در واقع این تغییر در اکولوژی آموزش، سطح ظاهری تحولاتی است که در فرهنگ ارتباطی و اندیشگی و یاددهی و یادگیری بشر در حال وقوع و بسط و توسعه است (بیتس، 1999؛ ردی و مانجولیکا، 2002).

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بازدید 1409

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 419 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    13
  • شماره: 

    25
  • صفحات: 

    126-144
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    16
  • دانلود: 

    0
چکیده: 

In this paper, an alternative approach in operational modal analysis is presented, utilizing image processing technique and transmissibility functions. Imaging sensors do not impose additional mass on the structure due to their non-contact nature, while transmissibility functions, independent of excitation type, can directly extract mode shapes. The innovation of this research lies in combining these two techniques to record dynamic responses and identify modal properties. To capture the temporal response history from video signals, the block-matching method with sub-pixel accuracy was employed. Validation was conducted by recording the response of the tip of a cantilevered steel beam subjected to impact excitation, using a high-speed camera and a laser vibrometer, simultaneously. The RMSE plots in the time domain and the PSD in the frequency domain indicate high accuracy of this method. Using this approach, the displacement time histories of various points on the structure were extracted from the video signals, and the modal properties, including natural frequencies, damping ratios, and mode shapes, were identified using the transmissibility matrix method. The results obtained from the proposed method were compared with the stochastic subspace identification (SSI) method and analytical solutions. The findings reveal the accuracy of the modal identification approach introduced in this article. The highest relative error in estimating the natural frequencies of the first and second modes, compared to the values from the laser method, are 0.19% and 0.13%, respectively, and in comparison to the analytical values, they are 0.34% and 1.5%, respectively.

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

بازدید 16

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همکاران: 

اطلاعات : 
  • تاریخ پایان: 

    1395
تعامل: 
  • بازدید: 

    236
کلیدواژه: 
چکیده: 

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

بازدید 236

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