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متن کامل


اطلاعات دوره: 
  • سال: 

    1401
  • دوره: 

    12
  • شماره: 

    47
  • صفحات: 

    7-32
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    199
  • دانلود: 

    39
چکیده: 

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

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اطلاعات دوره: 
  • سال: 

    1387
  • دوره: 

    32
  • شماره: 

    ب-3
  • صفحات: 

    265-277
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    855
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

کاربرد مفهوم معادل شبکه برای نمایش سیستم خارجی در تحلیل گذراهای سیستم قدرت به خوبی شناخته شده است. اما بهرحال، مورد چالش برانگیز در استفاده از یک معادل، تقریب زده شده با یک تابع گویا، تضمین پسیو بودن مدل مربوطه می باشد. در این رابطه، تکنیکهای ویژه ای برای تامین پسیوبودن مدل معادل از طریق یک روش post processing که تاثیراتش را روی مشخصات مدل اصلی مینیمم می کند، مورد نیاز است. در این مقاله، پسیوبودن ابتدا بوسیله تبیین مساله در ترمهایی از یک مساله اپتیمم سازی Convex که حل بهینه تام را تضمین می کند، اعمال می گردد. مساله اپتیمم سازی Convex بطور موثری بوسیله روشهای عددی interior-point که اخیرا توسعه داده شده، حل می گردد. این اعمال پسیو بودن نیز تام بوده، بدین معنی که اعمال پسیو بودن در یک ناحیه منجر به تخطی از پسیو بودن در نواحی دیگر نمی گردد.

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اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    53
  • شماره: 

    4
  • صفحات: 

    291-297
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    45
  • دانلود: 

    5
چکیده: 

In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing method.

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اطلاعات دوره: 
  • سال: 

    1388
  • دوره: 

    1
  • شماره: 

    4
  • صفحات: 

    3-10
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1324
  • دانلود: 

    331
چکیده: 

درخت مدل خطی محلی یا LOLIMOT که در آن از نوعی مدل فازی عصبی خطی محلی استفاده شده است، الگوریتمی بر اساس استراتژی تقسیم و حل می باشد که در آن حل مساله پیچیده از طریق تقسیم مساله به تعدادی زیر مساله کوچک تر (و از این رو ساده تر) صورت می پذیرد. بنابراین مشخصات این مدل فازی - عصبی (زیرمساله های کوچک تر شده) به مقدار زیادی به ساختار الگوریتم به کار برده شده جهت تقسیم بندی وابسته می باشد. الگوریتم LOLIMOT برای رسیدن به خروجی با خطای کمتر فضای مساله را به تعدادی مدل خطی محلی یا LLM تقسیم می نماید و پس از پیدا کردن بدترین LLM) LLM با خطای بیشتر) با تقسیم آن به دو LLM الگوریتم را ادامه می دهد. در این الگوریتم در هر تکرار از آن بدترین LLM با نرخ تقسیم 1/2 در جهت های متعامد بر فضای ورودی تقسیم می شود. در این مقاله به کمک الگوریتم بهینه سازی حدی به بهینه سازی نرخ تقسیم می پردازیم، نتایج پیاده سازی حاکی از آن است که کارایی نسخه جدید الگوریتم LOLIMOT از نظر شاخص میانگین مربعات خطا بهتر از الگوریتم اولیه است.

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نویسنده: 

حیدری علیرضا

اطلاعات دوره: 
  • سال: 

    1394
  • دوره: 

    1
تعامل: 
  • بازدید: 

    467
  • دانلود: 

    1452
چکیده: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

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اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    11
  • شماره: 

    2
  • صفحات: 

    61-74
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    176
  • دانلود: 

    27
چکیده: 

ABSTRACTDuring the last century, ports of Persian Gulf become the most important storage, refining and transportation of crude oil, oil derivation, petrochemical products and also, business activities. Nowadays, due to functional diversity between ports, the impact of port activities on the development of urban spaces will be different, and this issue leads to structural differences of port cities. The purpose of this research is to identify the key variables affecting the relations and spatial structure of port-city in Dubai as the most thriving and successful port-city in the Persian Gulf. This research is based on deductive reasoning and carried out by analysis of cross effects with secondary data (results of other prominent articles) and also primary data (questionnaire). sampling method is based on purposive sampling and Micmac software was used to analyze the data. Output of Micmac software shows the position of the instability of the system. Therefore, the position of each variables in the conceptual model can be categorized to driver, linkage, dependent, and autonomous factors. The research findings indicate 4 variables (like as “income, cost and investmnets in port-city”) can be introduced as a driver factor, 5 variables (like as “advanced multimodal transportation in the port”) can be introduced as a linkage factor, 6 variables (like as “quality of living environment and desirable city”) can be introduced as a dependent factor, 3 variables (like as “environmental protection and sustainable development of the city-port”) can be introduced as an autonomous factor. The rapid development of Dubai can be explained by the purposeful distribution of revenues from trade and tourismExtended AbstractIntroductionDuring the last century, ports of Persian Gulf become the most important storage, refining and transportation of crude oil, oil derivation, petrochemical products and also, business activities. The global increase in oil demand since the 1950s led to the creation of discovery of new oil wells and large industrial areas. With the construction of new oil or gas facilities in the port areas, increasing oil revenues contributed to the countries of the Persian Gulf region and form a new geographical relationship between ports and coastal cities which had an impact on the spatial structure and relation of them. Nowadays, due to functional diversity between ports, the impact of port activities on the development of urban spaces will be different, and this issue leads to structural differences of port cities. In the 1950s, Containerization (container loading technology) was based in some of the world's ports and created a huge transformation in the shipping industry, which had a significant impact on the development of ports. Although the ports of the Persian Gulf have made a significant contribution to the economic growth and physical development of other ports in the world, but few researches have been done on the variables and factors affecting the development of the spatial structure of the important ports of the Persian Gulf. This region, due to its unique geographical location, has always been considered as a most important corridor in the field of economic and transportation throughout history. Some of the most important energy and commercial ports in this region are: Dubai, Manama, Kuwait, Dammam, Doha, Bushehr, Bandar-Abbas and Assaluyeh. In this regard, the purpose of this research is to identify the key variables affecting the relations and spatial structure of port-city in Dubai as the most thriving and successful port-city in the Persian Gulf. MethodologyThis research is based on deductive reasoning and carried out by analysis of cross effects with secondary data (results of other prominent articles) and also primary data (questionnaire). The method used in this research is quantitative and the sampling method is based on purposive sampling. the variables affecting the spatial structure of port-city relations were identified in the form of a review of 31 prominent articles. 25 experts (who had comprehensive knowledge and information about the development process of the city-port of Dubai) participated to determine the effectiveness or influence of variables. Finally, the output of data analysis was done by the Micmac software. Results and discussionOutput of Micmac software shows the position of the variables in the diagram that it indicates their status in the system and their role in the dynamics and changes of the system. The method of distribution and dispersion of the variables in the spatial structure of port-city relations indicates the instability of the system. Therefore, based on the output of the system, the position of each variables in the conceptual model can be identified in five categories (driver, linkage, dependent, autonomous and regulatory variables). According to the results, some variables such as “the changes in the strategic positions” and “geopolitics of port-city”, “the modification of the management method” and “regional planning of the ports”, “the promotion of local governance in the relations between port-city” and “the way of national and international management of ports have been introduced as driver variables. On the other hand, five variables consist of “advanced multimodal transportation in the port” and “income, cost and investment in the port-city”, “the contrast and physical integration of the port - city space”, “the development of various industrial and production activities in the ports and their local hinterland” and “their qualities Financial and commercial policies of ports” have been introduced as linkage variables. Findings of research also shows that some variables consist of “quality of living environment and desirable city”, “quantity and quality of transit corridors (rail, road and air) to hinterland”, “construction and launching the new port (sea port or dry port)”, “terminal facilities and infrastructure and warehousing”, “conflict or convergence between the city and the port” and “increase in population growth rate and migration to the port - city” categorized as dependent variables. Three variables including “cultural and historical background of ports”, “use of cheaper energy, Less-polluted, clean and renewable energies in the city-port” and “environmental protection and sustainable development of the city-port” categorized as autonomous variables. Finally, a variable with the title of “improvement in management and information technology and development in loading, unloading and storage of commodities” have been introduced as regulatory variables. The findings of this research have a remarkable similarity with other researches carried out in the field of city-port relation and clearly emphasize the direct impact of the "investment in port-city" in the development of them. For example, Grossmann (2008) emphasized that city-port of Hamburg has become one of the largest ports in Northern Europe during the last few decades due to huge domestic and foreign investment. ConclusionThis research carried out in order to introduce and explain the key variables affecting the development of the spatial structure of the port-city of Dubai. On this basis, 21 variables have been extracted by systematic reviews of prominent articles. In the following, 25 experts were selected with the purposive sampling method. Among the 21 variables extracted, 4 variables (like as “geopolitics of port-city”) introduced as a driver factor, 5 variables (like as “advanced multimodal transportation in the port”) introduced as a linkage factor, 6 variables (like as “quality of living environment and desirable city”) introduced as a dependent factor, 3 variables (like as “environmental protection and sustainable development of the city-port”) introduced as an autonomous factor. The rapid development of Dubai can be explained by the purposeful distribution of revenues from trade and tourism. A part of these revenues has been directed towards investment in important transportation infrastructures such as airports and ports of this city. These strategies have a wide impact on improving the economic growth of the city and the development of the port in order to adapt with the global trade and advanced technologies. FundingThere is no funding support. Authors’ ContributionAuthors contributed equally to the conceptualization and writing of the article. All of the authors approved the content of the manuscript and agreed on all aspects of the work declaration of competing interest none. Conflict of InterestAuthors declared no conflict of interest. Acknowledgments We are grateful to all the scientific consultants of this paper.

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نویسندگان: 

Azizi Mahdi | Baghalzadeh Shishehgarkhaneh Milad | Basiri Mahla

اطلاعات دوره: 
  • سال: 

    2022
  • دوره: 

    6
  • شماره: 

    2
  • صفحات: 

    205-220
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    14
  • دانلود: 

    0
چکیده: 

Optimization is an act of decision-making to reach a point in which the overall behavior of the considered system is acceptable by the field's experts. In recent decades, construction companies have been willing to provide housing services with lower construction costs that people of different kinds can afford. Although academics have introduced form-dominant methods, using artificial intelligence (AI) in structural design has been one of the most critical challenges in recent years. In the current study, the applicability of the Crystal Structure Algorithm (CryStAl) as one of the recently developed metaheuristic algorithms is investigated in the optimum design of truss structures, in which the basic concepts of crystals, including the lattice and basis, are in perspective. For numerical purposes, the 10-bar, 72-bar, and 200-bar truss structures are considered as design examples. Furthermore, for constraint-handling purposes, a simple penalty approach is implemented in CryStAl. A complete statistical analysis is conducted through multiple optimization runs for comparative purposes; at the same time, other metaheuristic approaches have been derived from the literature. Based on the results of the CryStAl and other methods in dealing with truss optimization problems, the utilized method can provide better and more competitive results in most cases.

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اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    44
  • شماره: 

    1
  • صفحات: 

    43-52
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    319
  • دانلود: 

    0
چکیده: 

A new structure learning approach for Bayesian networks (BNs) based on asexual reproduction optimization (ARO) is proposed in this letter. ARO can be essentially considered as an evolutionary based algorithm that mathematically models the budding mechanism of asexual reproduction. In ARO, a parent produces a bud through a reproduction operator, thereafter the parent and its bud compete to survive according to a performance index obtained from the underlying objective function of the optimization problem, this leads to the fitter individual. The convergence measure of ARO is analyzed. The proposed method is applied to real-world and benchmark applications, while its effectiveness is demonstrated through computer simulations. Results of simulation show that ARO outperforms GA because ARO results in good structure and fast convergence rate in comparison with GA.

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نویسندگان: 

LAMBERTI L. | PAPPALETTERE C.

اطلاعات دوره: 
  • سال: 

    2009
  • دوره: 

    -
  • شماره: 

    20
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    182
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    24
  • شماره: 

    8
  • صفحات: 

    485-498
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    18
  • دانلود: 

    0
چکیده: 

این پژوهش به بهینه سازی توپولوژی مسائل اندرکنش سیال-سازه به روش مجموعه سطوح تراز می¬پردازد. به-منظور جفت کردن معادلات سیال-سازه از روش توصیف لاگرانژی-اویلری دلخواه (ALE) در فرمول بندی یکپارچه استفاده شده است. استفاده از توصیف ALE تحت فرمول¬بندی یکپارچه برای مسائل FSI، ضمن حذف ناپایداری¬¬های عددی ناشی از ترم همرفت، باعث افزایش سرعت و دقت حل اجزای محدود مسائل اندرکنش سیال-سازه خواهد شد. همچنین در نظر گرفتن سیال در حالت ناپایا (Unstaedy) امکان تفسیر توپولوژی بهینه را در هر لحظه از تحلیل فراهم می¬آورد. تابع هدف مسئله طراحی بهینه توپولوژی سازه، به حداقل رساندن نرمی سازه در حالت خشک تحت حجم معینی از دامنه طراحی سازه در نظر گرفته شده است. به منظور یافتن سرعت نرمال معادله واکنش- انتشار (RDE) از آنالیز حساسیت الحاقی مبتنی بر گرادیان نقطه ای استفاده شده است. نتایج حاصله از این رویکرد در مقایسه با سایر رویکردهای بهینه¬سازی توپولوژی موجود در ادبیات فنی نشان از دقت بالاتر و تشکیل مرزهای سازه ای واضح تر دارد.

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