1,041 research outputs found
On Time-sensitive Control Dependencies
We present efficient algorithms for time-sensitive control dependencies (CDs). If statement y is time-sensitively control dependent on statement x, then x decides not only whether y is executed but also how many timesteps after x. If y is not standard control dependent on x, but time-sensitively control dependent, then y will always be executed after x, but the execution time between x and y varies. This allows us to discover, e.g., timing leaks in security-critical software.
We systematically develop properties and algorithms for time-sensitive CDs, as well as for nontermination-sensitive CDs. These work not only for standard control flow graphs (CFGs) but also for CFGs lacking a unique exit node (e.g., reactive systems). We show that Cytron’s efficient algorithm for dominance frontiers [10] can be generalized to allow efficient computation not just of classical CDs but also of time-sensitive and nontermination-sensitive CDs. We then use time-sensitive CDs and time-sensitive slicing to discover cache timing leaks in an AES implementation. Performance measurements demonstrate scalability of the approach
PetroSurf3D - A Dataset for high-resolution 3D Surface Segmentation
The development of powerful 3D scanning hardware and reconstruction
algorithms has strongly promoted the generation of 3D surface reconstructions
in different domains. An area of special interest for such 3D reconstructions
is the cultural heritage domain, where surface reconstructions are generated to
digitally preserve historical artifacts. While reconstruction quality nowadays
is sufficient in many cases, the robust analysis (e.g. segmentation, matching,
and classification) of reconstructed 3D data is still an open topic. In this
paper, we target the automatic and interactive segmentation of high-resolution
3D surface reconstructions from the archaeological domain. To foster research
in this field, we introduce a fully annotated and publicly available
large-scale 3D surface dataset including high-resolution meshes, depth maps and
point clouds as a novel benchmark dataset to the community. We provide baseline
results for our existing random forest-based approach and for the first time
investigate segmentation with convolutional neural networks (CNNs) on the data.
Results show that both approaches have complementary strengths and weaknesses
and that the provided dataset represents a challenge for future research.Comment: CBMI Submission; Dataset and more information can be found at
http://lrs.icg.tugraz.at/research/petroglyphsegmentation
Book Reviews
Reviews of the following books: Kennebunkport: The Evolution of An American Town, Volume One, 1603-1923 by Joyce Butler; Patriot on the Kennebec: Major Reuben Colburn, Benedict Arnold and the March ot Quebec, 1775 by Mark A. York; Canoe Indians of Down East Maine by William A. Havilan
Методика прогноза дождевых паводков в бассейне Верхнего Амура (на примере р. Онон)
Актуальность работы. Бассейн Амура относится к паводкоопасному региону. Дождевые наводнения в бассейне верхнего Амура, носящие катастрофический характер, наблюдались за последнее столетие 8 раз. Они охватывали одновременно огромные территории, сопровождались человеческими жертвами, разрушением жилых и производственных зданий, инженерных коммуникаций. Эффективным способом борьбы с наводнениями является регулирование речного стока путем создания водохранилищ. Существующих водохранилищ в речной системе Амура не хватает, чтобы эффективно регулировать сток воды. Их строительство предусмотрено в планах дальнейшего освоения региона. Прогнозы притока паводковых вод являются одной из ключевых задач, позволяющих минимизировать ущерб от паводков и определить наиболее рациональный режим эксплуатации существующих и вновь создаваемых водохранилищ. Цель работы: на примере реки Онон исследовать процессы формирования наводнений и разработать методику их краткосрочного прогноза в бассейне верхнего Амура. Методы исследования: методы водного баланса, географо-гидрологические, статистические, математическое моделирование процессов формирования стока. Результаты. Для реализации прогноза ежедневных расходов (уровней) воды дождевых паводков адаптирована концептуальная модель Д.А. Буракова, используемая в сибирских подразделениях Росгидромета. В качестве ландшафтно-гидрологической основы построения модели принято деление бассейна на районы и высотные зоны. Исходной территориальной единицей осреднения гидрометеорологических характеристик в бассейнах горных рек является высотная зона. В пределах высотной зоны территориальная неравномерность распределения запасов снега и емкостного поглощения воды учитывается с помощью распределений вероятности. Отрезки времени, в течение которых суточное поступление воды на поверхность бассейна превышает суточное испарение и просачивание, образуют последовательные паводкообразующие периоды. Для каждых суток паводкообразующего периода рассчитывается водоотдача высотных зон на основе инфильтрационно-емкостной модели Е.Г. Попова, гравитационный запас воды на склонах и приток в русловую сеть. В основу модели расчета добегания притока воды по русловой сети положен интеграл свёртки (генетическая формула паводка). В результате выполненных исследований разработана методика прогноза ежедневных уровней воды в русловой системе р. Онон. Испытания методики в оперативном режиме в Читинском гидрометеорологическом центре показали ее эффективность.Relevance. The Amur basin is situated in a flood-inclined region. Over the course of the past century the disastrous pluvial flooding have occurred in the basin eight times. They covered huge territories, took peopleґs lives and caused considerable damage to residential and industrial buildings, engineering systems. One of the efficient methods to struggle the floods is to regulate the river run-off developing flood-control reservoirs. The number of existing reservoirs on the Amur river system is insignificant to control efficiently the river run-off. Their building is tied with further region development. The forecast of flood water inflow allows minimizing damage and identifying the most rational reservoir release rules for the existing and expected reservoirs. Aim of the research is to investigate the floods formation by the example of the Onon river and to develop the methods for short-term forecast of floods in the upper Amur basin. Research methods: water balance method, geographical and hydrological methods, statistical method, mathematical modeling of run-off formation. Results. The Burakovґs conceptual model is adapted to forecast daily rain floods water flows. This model is used by the Siberian department of the Federal Service for Hydrometeorology and Environmental Monitoring of Russia. The landscape and hydrological basis for this model is the basin division into areas and altitudinal zones. The altitudinal zone is an initial territorial unit of averaging the hydrological characteristics of mountain rivers. Within the altitudinal zone, territorial irregularity of snow cover distribution and capacitive water absorption are taken into account by probability distribution. The periods, when the diurnal water entry to the surface of the basin exceeds the diurnal evaporation and infiltration, compose successive flood-forming periods. For each day of a flood-forming period, the water yield is estimated using the Popovґs infiltration capacitive model. Besides, the gravitational water storage on the slopes and the inflow in the channel network are calculated. The method, describing water lag along the river channels, is based on applying the convolution integral (the genetic flood formula). As a result of the research, the author has developed the method of forecasting daily water levels in the Onon riverbed system. The method was applied by the Chita department of the Federal Service for Hydrometeorology and Environmental Monitoring of Russia and proved its efficiency
Endocrinology: Clinical significance of invisible or partially visible luteinizing hormone
It is well known that luteinizing hormone (LH), like many other glycoproteins, is heterogeneous and presents several circulating isoforms. Recently, new sensitive immunometric assays measuring intact LH were developed. These assays have been found to underestimate or to be incapable of recognizing LH in some patients. This study was undertaken to determine the prevalence of such cases and to define their clinical characteristics. We compared three LH assays using as capture antibodies either a monoclonal antibody that reacts exclusively with intact LH (ES 600 Boehringer, Stratus Baxter) or a monoclonal antibody against the β subunit of LH (IMX Abbott). In 17% of 90 patients tested, ES 600 measured > 50% lower LH concentrations when compared with the EVIX. Moreover, in two cases LH was not detectable by ES 600 or Stratus, whereas it was normal with the EVIX. We found another five such cases and discuss here the clinical data and results of different hormone measurements in these seven cases of ‘invisible LH'. Although bioactive LH (mouse Leydig cell assay) was normal, the existence of low or even undetectable LH was clinically confusing and led to expensive complementary investigations such as gonadotrophin-releasing hormone analogue tests and magnetic resonance imaging. The uses and limitations of these assays are illustrated by different clinical situations in which the results of the different assays have been misleadin
Encoding of naturalistic optic flow by motion sensitive neurons of nucleus rotundus in the zebra finch ( )
Eckmeier D, Kern R, Egelhaaf M, Bischof H-J. Encoding of naturalistic optic flow by motion sensitive neurons of nucleus rotundus in the zebra finch ( ). Frontiers in Integrative Neuroscience. 2013;7:68.The retinal image changes that occur during locomotion, the optic flow, carry information about self-motion and the three-dimensional structure of the environment. Especially fast moving animals with only little binocular vision depend on these depth cues for maneuvering. They actively control their gaze to facilitate perception of depth based on cues in the optic flow. In the visual system of birds, nucleus rotundus neurons were originally found to respond to object motion but not to background motion. However, when background and object were both moving, responses increased the more the direction and velocity of object and background motion on the retina differed. These properties may play a role in representing depth cues in the optic flow. We therefore investigated, how neurons in nucleus rotundus respond to optic flow that contains depth cues. We presented simplified and naturalistic optic flow on a panoramic LED display while recording from single neurons in nucleus rotundus of anaesthetized zebra finches. Unlike most studies on motion vision in birds, our stimuli included depth information. We found extensive responses of motion selective neurons in nucleus rotundus to optic flow stimuli. Simplified stimuli revealed preferences for optic flow reflecting translational or rotational self-motion. Naturalistic optic flow stimuli elicited complex response modulations, but the presence of objects was signaled by only few neurons. The neurons that did respond to objects in the optic flow, however, show interesting properties
Die Außenpolitik gegenüber den Vereinigten Staaten und Kanada
Die österreichische Außenpolitik gegenüber den Vereinigten Staaten ist gekennzeichnet durch das Verhältnis eines Kleinstaates zur hegemonialen Supermacht. Das
Verhältnis zur Mittelmacht Kanada fndet hingegen eher auf Augenhöhe statt. Zwar
sind die Beziehungen zu den USA durchwegs gut, jedoch hat die Relevanz Österreichs für die USA stetig abgenommen. In den Beziehungen zu Kanada gibt es
wichtige Schnittmengen, vor allem im Bereich des Engagements in internationalen
Institutionen, jedoch ebenfalls Spannungspunkt
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