Energy saving in agricultural buildings through fan motor control by variable frequency drives

A comparison was conducted between ON–OFF and variable frequency drive (VFD) systems to control ventilation fans of greenhouses and poultry houses. The study aimed to determine the effect of each system on the energy consumption and resulting microclimate within the houses. The experiments were carried out in a commercial-size greenhouse in which pepper was grown and in commercial poultry houses. Reducing the fan speed with the VFD system resulted in reductions in the airflow rate through the houses and energy consumption, the latter being much more significant. The study showed that VFD control can reduce electricity consumption compared with ON–OFF operation. In the present study, the average energy consumption with the VFD control system was about 0.64 and 0.75 of that with an ON–OFF system in the greenhouse and poultry houses, respectively. The average greenhouse daily air temperatures and humidity ratios obtained with each control system between 07:00 and 18:00 were nearly equal. The results obtained in the greenhouse further showed that the VFD system has a greater potential than the ON–OFF, to reduce the range of amplitude variations in the air temperature and humidity ratio within the greenhouse. The average air temperatures over day and night, in the poultry houses, with each control system were nearly equal. The relative humidity, however, was slightly lower with VFD than with ON–OFF. Reductions in the range of amplitude variations of the air temperature and humidity were also observed in the poultry houses.     

Localization of primitives using adaptive projections

An application of an active method in order to compute highly accurate 3D localization of point features from few projections is presented. The angle of projection of the image is controlled by the system and directed to extract 3D information from the environment in a manner leading to accurate location in less computation.This model is relevant for tomographic reconstruction, for feature based stereo and for model based robot registration.     

Economic determination of specification levels and allocation priorities of semiconductor products

We construct and analyze an economically efficient way of pricing and allocating semiconductor chips of which production technology is characterized by persistent quality variations and of which production capacity is exceeded by potential demand. In our model, specification levels and allocation priorities of competing orders from customers are systematically determined for a single profit maximizing producer. In the proposed scheme, the producer offers a 'product line' of priority classes under an allocation rule that always supplies higher priority classes with higher spec, level chips. This product line design and allocation rule enable us to cast the producer's profit maximization problem as a nonlinear programming formulation. Also, we investigate the optimality of the proposed allocation rule and derive conditions under which the profitability of downgrading is determined.     

Attentive transmission

A simple attention-based model is proposed for efficient transmission of visual information using multiresolution structures. Images are sampled nonuniformly in space and time, such that sampling is dense at the focus of attention and sparse in the periphery (retinal-like). Assuming that the focus of attention usually corresponds to eye position while scanning an image, image features which are “eye catching” (such as sharp edges, motion, and high flicker rate) are used to drive the dense center of sampling. The transmitted image is reconstructed by combining each new sample with previous samplings to give progressive transmission. The selection of sampling points depends only on previously transmitted information, and only sampled values without their location need to be transmitted.     

A Combinatorial Library of Lipid Nanoparticles for RNA Delivery to Leukocytes

Lipid nanoparticles (LNPs) are the most advanced nonviral platforms for small interfering RNA (siRNA) delivery that are clinically approved. These LNPs, based on ionizable lipids, are found in the liver and are now gaining much attention in the field of RNA therapeutics. The previous generation of ionizable lipids varies in linker moieties, which greatly influences in vivo gene silencing efficiency. Here novel ionizable amino lipids based on the linker moieties such as hydrazine, hydroxylamine, and ethanolamine are designed and synthesized. These lipids are formulated into LNPs and screened for their efficiency to deliver siRNAs into leukocytes, which are among the hardest to transfect cell types. Two potent lipids based on their in vitro gene silencing efficiencies are also identified. These lipids are further evaluated for their biodistribution profile, efficient gene silencing, liver toxicity, and potential immune activation in mice. A robust gene silencing is also found in primary lymphocytes when one of these lipids is formulated into LNPs with a pan leukocyte selective targeting agent (β₇ integrin). Taken together, these lipids have the potential to open new avenues in delivering RNAs into leukocytes.     

Opportunistic information dissemination in mobile ad-hoc networks: the profit of global synchrony

The topic of this paper is the study of information dissemination in mobile ad-hoc networks by means of deterministic protocols. We assume a weak set of restrictions on the mobility of nodes, parameterized by α, the disconnection time, and β, the link stability time, such that the mobile ad-hoc networks considered are connected enough for dissemination. Such a connectivity model generalizes previous models in that we assume much less connectivity, or make explicit the assumptions in previous papers. The protocols studied are classified into three classes: oblivious (the transmission schedule of a node is only a function of its ID), quasi-oblivious (the transmission schedule may also depend on a global time), and adaptive. The main contribution of this work concerns negative results. Contrasting the lower and upper bounds derived, interesting complexity gaps among protocol-classes are observed. These results show that the gap in time complexity between oblivious and quasi-oblivious (hence, adaptive) protocols is almost linear. This gap is what we call the profit of global synchrony since it represents the gain the network obtains from global synchrony with respect to not having it. We note that the global synchrony required by the efficient quasi-oblivious protocol proposed is simply achieved by piggybacking in the messages sent the time at the source node, as a global reference.     

Sensation Seeking and the Aversive Motivational System.

Sensation seeking (SS) has traditionally been viewed as a phenomenon of the appetitive motivational system. The limited SS research exploring contributions from the aversive motivational system reveals greater anxious reactivity to dangerous activities among low sensation seekers. The present study extends this line of work by comparing levels of fear and anxiety during anticipation of predictable and unpredictable aversive stimuli across high- and low-SS groups. Low sensation seekers displayed greater fear-potentiated startle (FPS) to predictable aversive stimuli, and only those low on SS showed FPS and skin conductance response effects during experimental contexts in which aversive stimuli were delivered unpredictably. Findings implicate enhanced apprehensive anticipation among those low on SS as a potential deterrent for their participation in intense and threatening stimulus events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coordinated motion planning for two independent robots

We present anO(n ²) algorithm for planning a coordinated collision-free motion of two independent robot systems of certain kinds, each having two degrees of freedom, which move in the plane amidst polygonal obstacles having a total ofn corners. We exemplify our technique in the case of two planar Stanford arms, but also discuss the case of two discs or convex translating objects. The algorithm improves previous algorithms for this kind of problems, and can be extended to a fairly simple general technique for obtaining efficient coordinated motion planning algorithms.