فیلترها/جستجو در نتایج    

فیلترها

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متن کامل


نویسندگان: 

Chowthri V. | Uma A. | Kalpana P.

اطلاعات دوره: 
  • سال: 

    2021
  • دوره: 

    12
  • شماره: 

    Special Issue
  • صفحات: 

    1827-1833
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    35
  • دانلود: 

    0
چکیده: 

An adaptive filter is a real-time computational device that iteratively simulates the relationship between a filter's input and output signals. It is based on an adaptive algorithm that iteratively self-adjusts the linear filter coefficients to decrease the power of e. (n). The LMS method is one of the most widely used adaptive algorithms for adjusting the coefficients of adaptive filters, among others. The error-computation block and the weight-update block, which determine the filter's efficiency, are the two key computing blocks of the direct-form LMS adaptive filter. In this paper, adaptive filter is implemented in two different architectures namely, zero adaptation delay adaptive filter and two adaptations delay adaptive filter which results in low power consumption and less area complexity. Zero adaptation delay adaptive filter provides nearly 52\% savings in the area and the delay decreases by 26\% in two adaptations delay adaptive filter over the conventional adaptive filter. Hence based on the required speed and area for the application, any one of the proposed structures can be used.

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نویسندگان: 

TAVAFI M.

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    2
  • شماره: 

    1
  • صفحات: 

    59-62
تعامل: 
  • استنادات: 

    2
  • بازدید: 

    227
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 227

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اطلاعات دوره: 
  • سال: 

    2025
  • دوره: 

    11
  • شماره: 

    1
  • صفحات: 

    264-273
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    0
  • دانلود: 

    0
چکیده: 

This study proposes a numerical investigation for assessing the primary design parameters influencing the efficiency of a Darrieus type vertical axis wind turbine. The methodology consists in the numerical solution of the continuity and momentum equations utilizing the Unsteady Reynolds Averaged Navier-Stokes (URANS) approach. The turbulence closure model is the SST k-ω, and the Finite Volume Method is applied to solve the three-dimensional geometries. The findings confirm that variations in solidity and aspect ratio of twisted blade turbines, in comparison to straight blade configurations, exert a similar influence on the torque coefficient, surpassing the impact of blade torsion angle variations. Results corroborated previous findings of literature about the fluctuations in the torque coefficient (Cm) being smoothed in 55% when helical blades are used in comparison with straight configuration. However, the increase in blade torsion angle corresponded to a decrease in the torque coefficient, with maximum difference of 37% when solidity (σ) is σ = 0. 75 and the ratio between height and radius of the turbine is H/R = 1. 5. Results also demonstrated that the increase in the solidity from σ = 0. 4 to 0. 8 reduced the effect of the ratio H/R on the Cm. The increase of σ allowed a gain in Cm of nearly 60%. For constant σ and tip speed ratio (λ), the increase of H/R from 2. 5 to 7. 5 led to an increase of 79% in Cm. In general, results supplied a guideline on the influence of λ, twisted angle, σ, and H/R on the performance of helical Darrieus turbines.

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اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    52
  • شماره: 

    3
  • صفحات: 

    189-194
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    127
  • دانلود: 

    38
چکیده: 

Intracytoplasmic sperm injection (ICSI) is one of the most successful techniques of Assisted Reproductive Technology (ART) and is mostly in use for the treatment of infertility with male factors. In this method, before injecting sperm into the intracytoplasmic of the oocyte, cumulus cells around the oocyte must be stripped to facilitate the injection process. To achieve this, both enzymatic and mechanical methods are used in embryological laboratories for denudation, which has major deficiencies, including the possibility of damaging the oocyte prior to the injection process. In this research, a microfluidic-based device is introduced for the separation of cumulus cells around the oocyte with minimum manual operations. The results prove high efficiency, and non-destructive denudation of the oocyte with the reduced amount of culture medium leads to the low-cost preparation process of oocytes. The process can also be integrated with ICSI chips under development and will be reported shortly.

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نشریه: 

هویت شهر

اطلاعات دوره: 
  • سال: 

    1396
  • دوره: 

    10
  • شماره: 

    28
  • صفحات: 

    5-18
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1526
  • دانلود: 

    595
چکیده: 

انسجام کالبدی کیفیتی است که در کالبد شهرهای معاصر به سختی یافت می شود. در پاسخ به این مساله، هدف این پژوهش دستیابی به راهکارهای طراحی شهری است که با استفاده از آنها بتوان به کالبدی منسجم تر و پاسخگو به نیازهای معاصر شهروندان دست یافت. در این راستا، در قالب یک تحقیق کیفی و با مرور اسناد کتابخانه ای و پیمایش میدانی، اصول فرم شهر بر پایه نظریه سیستم های پیچیده در بافت تاریخی شهر شیراز مورد سنجش قرار می گیرد تا از این طریق امکان به کارگیری این اصول به عنوان پایه ای نظری برای راهنمای طراحی مورد ارزیابی قرار گیرد. نتایج حاصل نشان می دهد که محدوده قدیمی شهر شیراز بر اساس اصول فرم شهر در نظریه پیچیدگی از انسجام کالبدی برخوردار بوده و بنابراین اصول مذکور قابل تعمیم به این محدوده است و می توان بر اساس آنها، راهکارهایی را برای افزایش انسجام کالبدی شهرهای معاصر با توجه به شرایط زندگی امروز ارائه کرد.

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نویسندگان: 

, , ,

نشریه: 

اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

  • شماره: 

  • صفحات: 

    41-48
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    24
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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نویسندگان: 

Hanaee Toktam | Farhangdoust Hadi

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    11
  • شماره: 

    2
  • صفحات: 

    133-152
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    202
  • دانلود: 

    30
چکیده: 

ABSTRACT The attention of contemporary planners to environmental factors and increasing awareness and communication of man with his surrounding environment has increased the layers and defining factors of design and planning concepts. In such a way, a common problem with the issue of environmental capabilities to respond was put in front of the planners. The collection of ideas presented in this era was in the form of responsive planning, focusing on the maximum use of environmental capabilities. The necessity of the emergence of a comprehensive discourse to overcome the plurality of factors, definitions and design methods in the environmental fields has been given less attention. Based on this, the current research aims to organize the leading theories in this field in a targeted manner and seeks to improve them based on their synergy. The structural question of this research is the meanings, examples and meaningful contexts of flexibility in various aspects and scales of urban planning. The research method used is qualitative thematic analysis with the help of artificial intelligence in MAXQDA software in a 6-step processing process. The important application of this research is to structure the minds of the planners of this field to reduce the scattered and interdisciplinary problems of the resources. The results of this research revealed dimensions such as identification and recognizability, diversity and changeability, adaptability and expandability, distribution, separation and continuity, organization and compatibility in the field of flexibility and related to the corresponding parts in urban planning   Extended Abstract Introduction Responsiveness-based design and planning emphasizing the maximum use of environmental capacities to meet users' needs implicitly cause a targeted improvement of environmental quality. As the environmental awareness of contemporary man has expanded and the platforms have become more diverse, many challenges are raised in the field of environment-oriented in the field of infrastructure quality and service provision. Urban developments and new developments in cities should be interpreted with integrated conceptualization. The conceptualization of interpretive flexibility in the planning and designing of public spaces in the city is used as an interdisciplinary perspective in urban space design to open and discuss its connection and potential as an approach to strengthening social cohesion and inclusion. The general definition of flexibility is that it can create places with new forms of meaning and be used for different groups to strengthen its coherence and multidisciplinary inclusion in terms of design and planning of space and body. On this basis, the concept of flexibility is proposed as a principle in the context of design and planning due to its wide range of effects on background phenomena. The history of such a role can be seen in the diversity of users' needs. In such a way, it is impossible to express the specific time and area of the need to pay attention to this concept. This is in line with Oldenburg's theory of "social public spaces," in which being in public space, communicating with people and the environment through observing the streets, sidewalks, squares, and parks of the city is a necessary step for people as a part of their social life. The meaningfulness of the design of the artificial environment was considered. In any case, in the contemporary era, on the one hand, at the same time as the quantitative and qualitative increase of human environmental awareness, there is no longer any phenomenon in the eyes of contemporary man arising from a unique aspect and range of factors. On the other hand, his life needs in the individual and collective dimensions have seen a high diversity, which has led to the formation of multiple semantic domains of past flexibility. The meaning of flexibility in such an interdisciplinary platform and basic design refers to the concept of understanding and responding quickly and efficiently to environmental changes. Such a holistic definition for this broad field of environmental design means the implicit acceptance of the role of scale in the meaningful domain of these concepts. On a macro scale, it means making design options to increase the presence, participation, and power of choices of users of the environment in participatory urban planning and design methods, and on a small scale, it means making design options to increase spatial quality and, as a result, the quality of activities. The daily activities of environmental users are through selection against the "dominant space." Flexibility at different scales is crucial for dimensional optimization, shaping, and structuring spatial features, leading to improved performance of space components and spaces. The development of the concept of "flexibility" from various studies in metropolitan to micro scales, such as interior architecture, allows it to pass the discourse of responsiveness to provide a broad approach to environmental design in which different values, interests, and priorities are prioritized. As a result, the issue of flexibility in environmental design has been raised as a multi-dimensional field in the design and planning of the basic environment. The breadth and complexity of this concept have made the researchers of this field deal with it in one or more ways, and it has been avoided to provide a comprehensive framework about the nature and structuring processes. The current research presents a structured view of flexibility in architecture and urban planning with an environmental approach.   Methodology The methodology to achieve this goal is to use the macro research method and achieve a comprehensive framework by combining categorized interpretations. In such a way that by sorting and categorizing these concepts and bases in a new way, he has found a new level of theoretical findings, which will be a suitable answer for the gaps in scientific knowledge and scientific methods created in this field. In this context, the research method "thematic analysis" has been used with a qualitative approach and the use of library resources. Also, to overcome the breadth and complexity of these concepts and the multi-layer networking of concepts in this research method, artificial intelligence has been used in MAXQDA research assistance software.   Results and discussion In the meantime, attention should also be paid to the fields of influence and application of the results of this research because designers refer to flexibility as the creator of environmental qualities, including dynamism. Also, since flexibility, along with the principles of readability and adaptability, affect the lifestyle and behavioral patterns of the audience of environmental design in architecture and urban planning, it will also be effective in dealing with the challenge of complexity in environmental design factors. One of the key questions for achieving research goals on this issue is how flexibility in environmental design impacts the relationship between flexibility and scale.   Conclusion The most important finding of this research suggests that first, it requires a focus on the conditions under which the processes of perceiving human abilities and discovering the needs of the human audience can manifest. The theoretical framework arises from a comparative approach between design disciplines. These conditions are independent of the final state of the design product, and strengthening the environmental capacities will lead to a direction and an area that includes environmental flexibility. By responding to new situations, the construction of the space and the body within a space building can be adapted to various configurations. Even though the environment may remain constant, the designed place will continue functioning as a strong living system over time.  It also seems that the nature of issues related to flexibility has complexity. Considering that the quality of flexibility in urban planning and architecture is significant in multilevel and multifaceted scales from micro to macro, it is important to pay attention to the scale of different variables. In order to reduce this problem, the consistency and adjustment of the scale of the variables measured in a specific analysis should be considered in the first step.   Funding There is no funding support.   Authors’ Contribution All of the authors approved the content of the manuscript and agreed on all aspects of the work.   Conflict of Interest Authors declared no conflict of interest.   Acknowledgments We are grateful to all the scientific.

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اطلاعات دوره: 
  • سال: 

    2024
  • دوره: 

    15
  • شماره: 

    2
  • صفحات: 

    71-86
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    9
  • دانلود: 

    0
چکیده: 

The paper aims at developing a model for improving service productivity in public organizations based on the service complexity approach. This is an applied, descriptive qualitative and, quantitative paper. The population in the qualitative section (grounded theory) includes 16 experts in the field of productivity in the university and managers of government organizations in Tehran province who were selected by theoretical sampling method as a method of targeted sampling. The statistical population in the structural equations section includes three categories: 1) Managers and experts of government service organizations; 2) Experts and deputies of government service organizations and, 3) Consultants and experts of government service organizations. In this section, we used multi-stage relative stratified sampling, which according to Cochran's formula, a total of 384 samples acceptable. Thus, the questionnaires were randomly distributed in each of the five regions of the country and, the data from 390 questionnaires were completed through the data analysis algorithm in PLS software. Having analyzed the interviews based on the grounded theory method and in NVivo Plus 2020 software and by open coding, we obtained 143 items as basic concepts from the text of the interviews, which were classified into 31 sub-indices and 11 main indices and five dimensions. Then, we validated and approved the results of the qualitative section through the data analysis algorithm in the PLS software. Given the research findings, we presented and fitted the model of improving service productivity in public organizations based on service complexity in a paradigm model.

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اطلاعات دوره: 
  • سال: 

    1399
  • دوره: 

    50
  • شماره: 

    3 (پیاپی 93)
  • صفحات: 

    1315-1328
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    190
  • دانلود: 

    89
چکیده: 

ساختار سخت افزاری سیستم اعداد مانده ای متشکل از چندین واحد شامل مبدل مستقیم، واحدهای محاسباتی مجزا برای انجام جمع و ضرب پیمانه ای و مبدل معکوس است. مبدل های مستقیم و معکوس که برای ارتباط سیستم اعداد مانده ای با دیگر مدارهای دیجیتال نیاز است، در واقع سربار سیستم می باشند زیرا باعت افزایش سطح تراشه و توان مصرفی می شوند. این مقاله، برای اولین بار، یک مبدل ترکیبی برای سیستم اعداد مانده ای پیشنهاد می دهد که مبدل های مستقیم و معکوس را از طریق اشتراک سخت افزار، یک پارچه می کند. برای رسیدن به این هدف، از الگوریتم تبدیل درهم مبنا استفاده شده است تا روابط حسابی تبدیل معکوس در یک قالب مشابه با روابط حسابی تبدیل مستقیم قرار گیرند. سپس با استفاده از مالتی پلکسرها و تنظیم ورودی ها، از سخت افزار مبدل معکوس، برای انجام تبدیل مستقیم استفاده شده است. نتایج حاصل از پیاده سازی VLSI مبدل ترکیبی پیشنهادی مبتنی بر تکنولوژی TSMC-65nm، برای مجموعه پیمانه {2n-1, 22n, 2n+1-1}، نشانگر کاهش حداکثر 19 درصدی سطح تراشه در مقایسه با مجموع مبدل های مستقیم و معکوس است. این در حالی است که تاخیر مبدل ترکیبی پیشنهادی حداکثر 10 درصد از تاخیر مبدل معکوس مجزا بیش تر شده است.

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اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    1
  • شماره: 

    2
  • صفحات: 

    243-268
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    23
  • دانلود: 

    0
چکیده: 

رشد شتابان شهرها در غیاب ضوابط کنترلی مؤثر، پاسخگویی شهرها به نیازهای شناختی و فیزیولوژیکی شهروندان را با بحران مواجه نموده است. نوروشهرسازی به عنوان رویکردی نوظهور، با ادغام شهرسازی، روان شناسی محیطی و عصب شناسی، به تحلیل بازخوردهای عصبی مغز نسبت به محیط های شهری می پردازد تا تعامل مثبت انسان و محیط بازسازی شود. در این میان پیچیدگی بصری بعنوان عاملی که عدم تعادل در آن مستقیما با فیزیولوژی انسان در ارتباط است، در چارچوب این رویکرد می تواند از منظری جدید مورد مطالعه قرارگیرد. پژوهش حاضر پس از بررسی مفهوم پیچیدگی بصری در طراحی شهری، به طیف بهینه پیچیدگی بصری پرداخته و به معرفی امکانات نوروشهرسازی در بررسی این فاکتور محیطی می پردازد. مطالعات اخیر در حوزه نوروشهرسازی نشان داده اند که رابطه میان وحدت و تنوع در محیط های شهری را می توان از طریق تحلیل سرعت پردازش عصبی داده های بصری بررسی کرد. شواهد تجربی حاکی از آن است که امواج بتا با میزان پیچیدگی فرم های فراکتال ارتباط مستقیم دارند؛ داده های حاصل از الکتروانسفالوگرافی (EEG) نشان می دهند که این ابزار می تواند به عنوان راهکاری مؤثر برای بررسی تجربیات شناختی مرتبط با وحدت و تنوع و همچنین سرعت پردازش عصبی به کار رود. علاوه بر این، نوسانات فرکانس تتا در نواحی پیشانی و بالای پیشانی با عملکردهای شناختی نظیر حافظه کاری، حافظه اپیزودیک و جهتیابی ارتباط معناداری دارند. افزایش دامنه فعالیت سیگنال های EEG اغلب بیانگر کاهش نمایانی عناصر محیطی است، در حالی که کاهش دامنه این سیگنال ها به افزایش نمایانی این عناصر اشاره دارد. در نهایت، محدودیت های فنی ابزارهای نقشه برداری عصبی در محیط های واقعی، از جمله حساسیت به نویزهای محیطی و حرکت، به عنوان چالش های اصلی شناسایی شده اند. به همین دلیل، استفاده از محیط های واقعیت مجازی (VR) به عنوان ابزاری نوین برای کنترل متغیرهای محیطی و کاهش اثر محدودیت های فنی پیشنهاد می شود. این رویکرد امکان دستکاری سیستماتیک متغیرهای مرتبط با پیچیدگی بصری و بهبود دقت در ثبت داده های عصبی را فراهم می آورد.

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

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