The Acrobot, a two-link arm that is unactuated at the first joint, is challenging to control because it is an under actuated, nonlinear, continuous system. We describe a direct search algorithm for finding swingup trajectories for the Acrobot. The algorithm uses a Iookahead search that maximizes the Acrobot’s totaf energy in an N-step window. Because the controls are extremal and the number of ...

Introduction: Myocardial perfusion imaging is a nuclear medicine imaging method that is used to detect coronary artery diseases. One of the main sources of error in this imaging method is the detection of Compton scattered photons in the photopeak energy window used for data acquisition. This results in the degradation of the image contrast, and therefore decreases the...

1077-3142/$ see front matter 2012 Elsevier Inc. A http://dx.doi.org/10.1016/j.cviu.2012.12.005 q This paper has been recommended for acceptance ⇑ Corresponding author. Address: Dept. of EECS Gwanak, P.O. Box 34, Seoul 151-600, Republic of Kore E-mail addresses: [email protected] (H.Y. (K.M. Lee), [email protected] (S.U. Lee). The pixel labeling problems in computer vision are often for...

Draft is one of the most common complaints in the indoor environment. It may be caused by convective air currents along windows and other cold surfaces providing air movement in the occupied zone of heated spaces. The present paper comprises measurements of airflow characteristics (mean velocity, turbulence intenSity, energy spectra of the velocity fluctuations, etc.) in a wide range of spaces ...

In this paper, a novel dynamic contention window control scheme is presented to improve the performance and energy efficiency of IEEE 802.11-based CSMA/CA DCF wireless networks operating in ad-hoc mode. The number of competing nodes in physical carrier sense systems has a major influence on the probability of collisions and a subsequent impact on DCF performance and on the energy consumed. A ne...

The laser-driven MiniFlyer system is used to launch a small, thin flyer plate for impact on a target. Consequently, it is an indirect drive technique that de-couples the shock from the laser beam profile. The flyer velocity can be controlled by adjustment of the laser energy. The upper limits on the flyer velocity involve the ability of the substrate window to transmit the laser light without a...

A YAP(YAlO3 : Ce)-scintillating window, coated on its inner surface with an S20-photocathode, seals a cross-focusing hybrid photomultiplier tube (HPMT) equipped with a small p-i-n anode of 2-mm diameter. This new radiation detector separates X-ray lines down to about 2-keV peak energy from the HPMT noise. Its detection efficiency for high gamma energies depends on the YAP-window thickness and a...

OBJECTIVES Use of a positron emission tomography (PET)/single-photon emission computed tomography (SPECT) system facilitates the simultaneous acquisition of images with fluorine-18 fluorodeoxyglucose ((18)F-FDG) and technetium ((99m)Tc)-tetrofosmin. However, (18)F has a short half-life, and 511 keV Compton-scattered photons are detected in the (99m)Tc energy window. Therefore, in this study, we...

We theoretically and numerically investigate the nonparaxial self-accelerating beams in a Λ-type three-level energy system of rubidium atomic vapor in the electromagnetically induced transparency (EIT) window. In the EIT window, the absorption of the atomic vapor is small, and robust nonparaxial self-accelerating beams can be generated. The reason is that the energy of the tail transfers to the...

Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-o...