نتایج جستجو برای: given tec time series

تعداد نتایج: 2577805  

2007
Suqin Wu Kefei Zhang Yunbin Yuan Falin Wu

The atmospheric effects, especially the ionosphere, are the key limiting factors for real-time high accuracy positioning using the network RTK technique with a medium-to-long-range baseline separation. To investigate suitable approaches to improve ionospheric modeling towards a real-time CMlevel positioning using the Victorian continuously operating reference stations network (i.e. GPSnet) syst...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده علوم 1392

در نظر گرفتن یک فرض کلاسیک در ساختمان سری ها موجب شده است، مشاهدات را با یک الگوی خطی که ضرایبش با زمان تغییر نمی کند در نظر گیرند. اما بسیاری از سری های زمانی دارای میانگین و واریانس ثابتی در طول زمان نیستند در این شرایط مدل های اتورگرسیو مشروط به ناهمسانی واریانس اغلب به نتایج مطلوبی منجر می شوند. تحقیقات نشان داده اند مدل های شبکه عصبی برای نمایش رفتار غیرخطی داده ها نیز از عملکرد قابل توجهی...

Journal: :journal of arthropod-borne diseases 0
afshin ostovar epidemiology and biostatistics department, school of public health, tehran university of medical sciences, tehran, iran ali akbar haghdoost research center for modeling in health, institute for future studies in health, kerman university of medical sciences, kerman, iran abbas rahimiforoushani epidemiology and biostatistics department, school of public health, tehran university of medical sciences, tehran, iran ahmad raeisi malaria control office of moh and me, tehran university of medical sciences, tehran, iran reza majdzadeh knowledge utilization research center, tehran university of medical sciences, tehran, iran

background: the malaria early warning system is defined as the use of prognostic variables for predicting the occurrence of malaria epidemics several months in advance. the principal objective of this study was to provide a malaria prediction model by using meteorological variables and historical malaria morbidity data for malaria-en­demic areas in south eastern iran. methods: a total of 2002 l...

ژورنال: فیزیک زمین و فضا 2020

لایه یون‌سپهر از لایه‌های مهم جو زمین است که در اثر جذب تابش ماوراءبنفش و ایکس خورشیدی و برخورد ذرات باردار با اتم‌ها و مولکول‌های جو زمین و برهمکنش فوتوشیمیایی بین ترکیبات آن تشکیل می­شود. الکترون‌های آزاد در این لایه بر مسیر امواج رادیویی تأثیر می‌گذارد و هرگونه اختلال احتمالی در این لایه، تأثیر جدی در ارتباطات ماهواره‌ای، ارتباطات دقیق ناوبری و ارتباطات دوربرد می‌گذارد. پس شناخت مقادیر میانگ...

Journal: :journal of medical signals and sensors 0
saeedeh mobasheri hamid behnam parisa rangraz jahan tavakkoli

high‑intensity focused ultrasound (hifu) is a novel treatment modality used by scientists and clinicians in the recent decades. this modality has had a great and significant success as a noninvasive surgery technique applicable in tissue ablation therapy and cancer treatment. in this study, radio frequency (rf) ultrasound signals were acquired and registered in three stages of before, during, a...

Journal: :اقتصاد و توسعه کشاورزی 0
رضا مقدسی میترا ژاله رجبی

abstract autoregressive integrated moving average (arima) has been one of the widely used linear models in time series forecasting during the past three decades. recent studies revealed the superiority of artificial neural network (ann) over traditional linear models in forecasting. but neither arima nor anns can be adequate in modeling and forecasting time series since the first model cannot d...

Journal: :journal of computer and robotics 0
sahifeh poor ramezani kalashami faculty of engineering, department of artificial intelligence, mashhad branch, islamic azad university, mashhad, iran seyyed javad seyyed mahdavi chabok faculty of engineering, department of artificial intelligence, mashhad branch, islamic azad university, mashhad, iran

clustering is one of the known techniques in the field of data mining where data with similar properties is within the set of categories. k-means algorithm is one the simplest clustering algorithms which have disadvantages sensitive to initial values of the clusters and converging to the local optimum. in recent years, several algorithms are provided based on evolutionary algorithms for cluster...

Journal: :journal of advances in computer research 2014
haleh nazari homayun motameni babak shirazi

since the pioneering work of zadeh, fuzzy set theory has been applied to amyriad of areas. song and chissom introduced the concept of fuzzy time series andapplied some methods to the enrolments of the university of alabama. thereafter weapply fuzzy techniques for system identification and apply statistical techniques tomodelling system. an automatic methodology framework that combines fuzzytech...

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