Reduction of the Long-Term Inaccuracy from the AVHRR–Based NDVI Data

This paper investigated the normalized difference vegetation index (NDVI) stability in the NOAA/NESDIS Global Vegetation Index (GVI) data during 1982-2003, which was collected from five NOAA series satellites. An empirical distribution function (EDF) was developed to eliminate the long-term inaccuracy of the NDVI data derived from the AVHRR sensor on NOAA polar orbiting satellite. The instability of data results from orbit degradation as well as from the circuit drifts over the life of a satellite. Degradation of NDVI over time and shifts of NDVI between the satellites were estimated using the China data set, because it includes a wide variety of different ecosystems represented globally. It was found that the data for the years of 1988, 1992, 1993, 1994, 1995 and 2000 are not stable compared to other years because of satellite orbit drift, AVHRR sensor degradation, and satellite technical problems, including satellite electronic and mechanical satellite systems deterioration. The data for NOAA-7 (1982, 1983), NOAA-9 (1985, 1986), NOAA-11 (1989, 1990), NOAA-14 (1996, 1997), and NOAA-16 (2001, 2002) were assumed to be standard because the crossing time of satellite over the equator (between 1330 and 1500 hours) maximized the value of the coefficients. These years were considered as the standard years, while in other years the quality of satellite observations significantly deviated from the standard. The deficiency of data for the affected years were normalized or corrected by using the method of EDF and comparing with the standard years. These normalized values were then utilized to estimate new NDVI time series which show significant improvement of NDVI data for the affected years

Исследование влияния поляризации на метрологические характеристики сенсора кислорода

В роботі проводилося дослідження різних чинників, які впливають на метрологічні характеристики сенсору. Підвищення метрологічних характеристик приладів може бути досягнуто при використанні імпульсних методів поляризації електродів сенсорів. Новизна роботи полягає в застосуванні імпульсної поляризації сенсорів кисню та розробці нових методів обробки вихідних сигналів з метою підвищення метрологічних характеристик приладів. Досліджено кінетику процесів відновлення кисню на катодах сенсорів при поляризації імпульсною напругою. Застосування нових методів поляризації приводить до мінімального впливу роботи сенсора на рівноважні процеси в біологічних об’єктах, що підвищує точність вимірювання та забезпечує швидку реакцію приладу на зміну впливу зовнішніх чинників.The research of different factors influencing on the metrological characteristics of the sensor was conducted in the paper. The elevation of the devices’ metrological characteristics can be achieved by using pulsed methods of polarization of sensors’ electrodes. Novelty of work consists in application of pulse polarization of sensors of oxygen and development of new methods of processing of target signals for the purpose of increase of metrological characteristics of devices. Kinetics of the processes of oxygen reduction on sensors’ cathode under polarization of the pulse voltage is researched. Application of the new methods of polarization leads to minimal influence on the work of sensor on equilibrium processes in biological objects which increases accuracy of measurement and provides quick reaction of the device on the alteration of the effect of external factors.В работе проводились исследования различных факторов, влияющих на метрологические характеристики сенсора. Повышение метрологических характеристик приборов может быть достигнуто при использовании импульсных методов поляризации электродов сенсоров. Новизна работы заключается в применении импульсной поляризации сенсоров кислорода и разработке новых методов обработки выходных сигналов с целью повышения метрологических характеристик приборов. Исследована кинетика процессов восстановления кислорода на катодах сенсоров при поляризации импульсным напряжением. Применение новых методов поляризации приводит к минимальному влиянию работы сенсора на равновесные процессы в биологических объектах, что повышает точность измерения и обеспечивает быструю реакцию прибора на изменение воздействия внешних факторов

Fast Fencing

We consider very natural "fence enclosure" problems studied by Capoyleas, Rote, and Woeginger and Arkin, Khuller, and Mitchell in the early 90s. Given a set $S$ of $n$ points in the plane, we aim at finding a set of closed curves such that (1) each point is enclosed by a curve and (2) the total length of the curves is minimized. We consider two main variants. In the first variant, we pay a unit cost per curve in addition to the total length of the curves. An equivalent formulation of this version is that we have to enclose $n$ unit disks, paying only the total length of the enclosing curves. In the other variant, we are allowed to use at most $k$ closed curves and pay no cost per curve. For the variant with at most $k$ closed curves, we present an algorithm that is polynomial in both $n$ and $k$. For the variant with unit cost per curve, or unit disks, we present a near-linear time algorithm. Capoyleas, Rote, and Woeginger solved the problem with at most $k$ curves in $n^{O(k)}$ time. Arkin, Khuller, and Mitchell used this to solve the unit cost per curve version in exponential time. At the time, they conjectured that the problem with $k$ curves is NP-hard for general $k$. Our polynomial time algorithm refutes this unless P equals NP

Fast Fencing

International audienceWe consider very natural ”fence enclosure” problems studied by Capoyleas, Rote, and Woeginger and Arkin, Khuller, and Mitchell in the early 90s. Given a set S of n points in the plane, we aim at finding a set of closed curves such that (1) each point is enclosed by a curve and (2) the total length of the curves is minimized. We consider two main variants. In the first variant, we pay a unit cost per curve in addition to the total length of the curves. An equivalent formulation of this version is that we have to enclose n unit disks, paying only the total length of the enclosing curves. In the other variant, we are allowed to use at most k closed curves and pay no cost per curve.For the variant with at most k closed curves,we present an algorithm that is polynomialin bothn andk. For the variant with unit cost per curve, or unit disks, we presenta near-linear time algorithm.Capoyleas, Rote, and Woeginger solved the problem with at most k curves in nO(k) time. Arkin, Khuller, and Mitchell used this to solve the unit cost per curve version in exponential time. At the time, they conjectured that the problem with k curves is NP-hard for general k. Our polynomial time algorithm refutes this unless P equals NP

Robot-assisted pyeloplasty: outcomes for primary and secondary repairs, a single institution experience

INTRODUCTION: Robotic Pyeloplasty (RAP) is a technique for management of uretero-pelvic junction obstruction (UPJO). PURPOSE: To report outcomes of RAP for primary and secondary (after failed primary treatment) UPJO. MATERIALS AND METHODS: Single institution data of adult RAP performed from 2007 to 2009 was collected retrospectively following approval by our IRB. Database analysis including patient age, race, pre and post-operative imaging studies and perioperative variables including operative time, blood loss, pain and complications. RESULTS: Fifty-five adult patients underwent RAP (26 left/29 right) for UPJO including 9 secondary procedures from 2007 to 2009. Average follow-up was 16 months (1-36). Mean age was 41 years (18-71) with an average BMI of 27 (17-42), 32 were female. Majority were diagnosed with preoperative diuretic renal scintigraphy with obstructed side demonstrating mean function of 41% and t1/2 of 70 minutes. Mean operative time was 194 minutes with average blood loss less than 100 mL. Mean hospital stay was 1.7 days with an average narcotic equivalent dose of 15 mg. RAP for secondary UPJO took longer with more blood loss and had a lower success rate. Failure was defined as necessitating another procedure due to persistent pain and/or obstruction on diuretic renal imaging. One patient (2%) with primary UPJO failed and 2 patients (22%) with secondary UPJO failed. One major complication occurred. CONCLUSION: RAP is a good option for the treatment of patients with UPJO. Reported series have established that endopyelotomy has inferior success as a treatment for primary UPJO which compromises the success of subsequent treatment as demonstrated in our higher failure rate with secondary UPJO repair

Fast fencing

We consider very natural fence enclosure problems studied by Capoyleas, Rote, and Woeginger and Arkin, Khuller, and Mitchell in the early 90s. Given a set $S$ of $n$ points in the plane, we aim at finding a set of closed curves such that (1) each point is enclosed by a curve and (2) the total length of the curves is minimized. We consider two main variants. In the first variant, we pay a unit cost per curve in addition to the total length of the curves. An equivalent formulation of this version is that we have to enclose $n$ unit disks, paying only the total length of the enclosing curves. In the other variant, we are allowed to use at most $k$ closed curves and pay no cost per curve. For the variant with at most $k$ closed curves, we present an algorithm that is polynomial in both $n$ and $k$. For the variant with unit cost per curve, or unit disks, we present a near-linear time algorithm. Capoyleas, Rote, and Woeginger solved the problem with at most $k$ curves in $n^{O(k)}$ time. Arkin, Khuller, and Mitchell used this to solve the unit cost per curve version in exponential time. At the time, they conjectured that the problem with $k$ curves is NP-hard for general $k$. Our polynomial time algorithm refutes this unless P equals NP

Defending Financial Infrastructures Through Early Warning Systems: The intelligence cloud approach

Recent evidence of successful Internet-based attacks and frauds involvingnancial institutions highlights the inadequacy of the existing protection mechanisms, in which each instutition implements its own isolated monitoring and reaction strategy. Analyzing on-line activity and detecting attacks on a large scale is an open issue due to the huge amounts of events that should be collected and processed. In this paper, we propose a large-scale distributed event processing system, called intelligence cloud, allowing the nancial entities to participate in a widely distributed monitoring and detection effort through the exchange and processing of information locally available at each participating site. We expect this approach to be able to handle large amounts of events arriving at high rates from multiple domains of the financial scenario. We describe a framework based on the intelligence cloud where each participant can receive early alerts enabling them to deploy proactive countermeasures and mitigation strategies. Copyright © 2009 ACM