نتایج جستجو برای: estimation precision improvement

تعداد نتایج: 666828  

Journal: :محیط زیست طبیعی 0
امیرحسین حمیدیان استادیار گروه محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران مجید آتشگاهی کارشناس ارشد محیط زیست، دانشکدۀ منابع طبیعی، دانشگاه تهران محمدرضا حاجی‏هاشمی‏جزی کارشناس ارشد بیابان زدایی، دانشکدۀ منابع طبیعی، دانشگاه تهران ابوالحسن فتح آبادی دانشجوی دکتری آبخیزداری، دانشکدۀ منابع طبیعی، دانشگاه تهران، ایران

groundwater resources are the most important sources of water consumption (agriculture, industry and drinking water) in arid and semi-arid regions. the management of these water resources is more expensive and difficult than surface waters; therefore more complicated and economic methods are needed for determination of their quality and quantity. in this study geostatistical methods of kringing...

2010
Saeedeh Momtazi Matthew Lease Dietrich Klakow

A well-known challenge of information retrieval is how to infer a user’s underlying information need when the input query consists of only a few keywords. Question Answering (QA) systems face an equally important but opposite challenge: given a verbose question, how can the system infer the relative importance of terms in order to differentiate the core information need from supporting context?...

Journal: :EURASIP J. Adv. Sig. Proc. 2013
Jia Duan Lei Zhang Mengdao Xing

With the development of multi-functional radar systems, inverse synthetic aperture radar (ISAR) imaging with sparse-aperture (SA) data has drawn considerable attention in the recent years. Motion compensation and imaging are among the most significant challenges that SA-ISAR imaging frequently faces. In this paper, we focus on the autofocus scheme, in which a modified eigenvector-based autofocu...

Journal: :IEEE transactions on ultrasonics, ferroelectrics, and frequency control 2015
Elyas Shaswary Jahan Tavakkoli Yuan Xu

Time-delay estimation determines the relative displacement between two ultrasound echo signals. In this paper, we propose a new time-delay estimation algorithm which uses only the sign function to obtain the corresponding timedelay estimate. The performance of the proposed algorithm was compared with two established algorithms, i.e., normalized cross-correlation (NCC) and sum of squared differe...

1994
Peter Teunissen Paul de Jonge Christiaan Tiberius

One of the major problems in processing GPS phase observations is estimating the double-difference (DD) ambiguities as integers. Based on carrier phase data only, short observational time spans result in strongly correlated ambiguities and in very elongated ambiguity confidence ellipsoids. As a result the estimation of the integer least-squares ambiguities becomes an extremely time consuming ta...

2013
B. Jutzi M. Weinmann J. Meidow

In this paper, a new method for fusing optical and laserscanner data is presented for improved UAV-borne 3D mapping. We propose to equip an unmanned aerial vehicle (UAV) with a small platform which includes two sensors: a standard low-cost digital camera and a lightweight Hokuyo UTM-30LX-EW laserscanning device (210 g without cable). Initially, a calibration is carried out for the utilized devi...

2007
Adam Trendowicz Michael Ochs Axel Wickenkamp Jürgen Münch Yasushi Ishigai Takashi Kawaguchi

Managing software development productivity and effort are key issues in software organizations. Identifying the most relevant factors influencing project performance is essential for implementing business strategies by selecting and adjusting proper improvement activities. There is, however, a large number of potential influencing factors. This paper proposes a novel approach for identifying th...

Abbas Maghsoudi Nasser Madani Peyman Afza Shahrokh Paravarzar

Estimation of gold reserves and resources has been of interest to mining engineers and geologists for ages. The existence of outlier values shows the economic part of the deposits subject to the fact that don’t depend on the human or technical errors. The presence of these high values causes a pseudo dramatically increment in variance estimation of economical blocks when applying conventional m...

2014
Jieci Wang Zehua Tian Jiliang Jing Heng Fan

We study the quantum metrology for a pair of entangled Unruh-Dewitt detectors when one of them is accelerated and coupled to a massless scalar field. Comparing with previous schemes, our model requires only local interaction and avoids the use of cavities in the probe state preparation process. We show that the probe state preparation and the interaction between the accelerated detector and the...

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