3,163 research outputs found
Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake: Data collection/analysis techniques
The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed
Winter Wheat Test Results for South Dakota, 2002
The winter wheat variety recommendations for 2003 are listed in table 1. Comments: The dominant issue facing South Dakota agriculture in the 2002 crop season was the lack of moisture in the fall of 2001 and the winter and spring of 2002. Limited moisture led to a large deficit in subsoil moisture in many cropping regions of the state. This in turn resulted in many acres of winter wheat and other small grains being harvested for hay. The average winter wheat yield in the South Dakota Crop Performance Testing (CPT) Program was 39 bu/A for year 2002 and 48 bu/A for the 3-year period (2000-2002). Compared to 2001, this was a drop of 7 bu/A in both the 1- and 3-year CPT yield averages
Soybean Variety Trial Archive
This report features the available soybean variety trial data from 2003-2017. Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU
Corn Hybrid Trial Archive
This report features the available corn data from 2003-2017. Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU
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Using safety and liveness properties to drive learning in a multi-agent system
One of the strongest results in temporal logic is Chang, Manna and Pnueli's partitioning of reactive system properties into the classes of safety and liveness[1]. Safety and liveness properties state, intuitively and respectively, that something bad will not happen and that something good will eventually happen. In this paper we show how, in a multi-agent world, this safety/liveness partitioning can be used to drive learning. If an agent is introduced to a world and given a set of descriptions of system safety an liveness properties then how is it to discover how to behave in such a way as to satisfy them? Safety and liveness properties will influence agent behaviour, safety properties are cast as system norms exerting a restraining influence whilst liveness properties are cast as desires which exert a driving influence. Agents will randomly gather a set of atomic behaviours-simple actions which may be used individually, in combination or in conjunction with other agents. In order to discover behaviours which satisfy these system properties agents must have a "mischevious" element in their behaviour. Future worlds are given a preference ordering, when this ordering fails to provide clear guidance an agent may "mischeviously" select any available action not proscribed by safety norms. Undesirable world states are described by these safety norms and agents will be obliged to prevent these states by either refraining from actions which are known to bring them about or acting so as to attempt to clear these states if they are detected. A small number of dedicated coaching agents will assist "normal" agents in refining any behaviours they have developed. Coaches will also try to ensure that successful behaviours are propagated as quickly as possible. The mechanism for achieving these combined behaviours is a novel combination of belief update and belief revision. This arrangement provides a belief management framework which is capable of identifying factors governing the behaviour of the agent's world with no requirement for prior knowledge. The resulting set of beliefs will be filtered by an agent's desires and intentions so as to produce a partially ordered set of plausible worlds and, hence, a partial order on sets of available actions to control the agent's behaviour
Spring Wheat Variety Trial Archive
Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU
Oats Variety Trial Archive
This report features the available oats data from 2003-2017. Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU
Field Pea Variety Trial Archive
This report features the available pea data from 2003-2017. Crop performance testing results are released annually through the activities of SDSU Extension and the South Dakota Agricultural Experiment Station at SDSU
Noninvasive assessment of arterial compliance of human cerebral arteries with short inversion time arterial spin labeling
A noninvasive method of assessing cerebral arterial compliance (AC) is introduced in which arterial spin labeling (ASL) is used to measure changes in arterial blood volume (aBV) occurring within the cardiac cycle. Short inversion time pulsed ASL (PASL) was performed in healthy volunteers with inversion times ranging from 250 to 850 ms. A model of the arterial input function was used to obtain the cerebral aBV. Results indicate that aBV depends on the cardiac phase of the arteries in the imaging volume. Cerebral AC, estimated from aBV and brachial blood pressure measured noninvasively in systole and diastole, was assessed in the flow territories of the basal cerebral arteries originating from the circle of Willis: right and left middle cerebral arteries (RMCA and LMCA), right and left posterior cerebral arteries (RPCA and LPCA), and the anterior cerebral artery (ACA). Group average AC values calculated for the RMCA, LMCA, ACA, RPCA, and LPCA were 0.56%±0.2%, 0.50%±0.3%, 0.4%±0.2%, 1.1%±0.5%, and 1.1%±0.3% per mm Hg, respectively. The current experiment has shown the feasibility of measuring AC of cerebral arteries with short inversion time PASL
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