Artificial intelligence (AI) and robotics in travel,hospitality and leisure

Electronic Markets -     

A real time cost effective geometry calibration method for isocenter tracking of a rotating gantry using optical vision sensors

In this paper, a real time and cost effective deformation sensor system is proposed to verify isocenter sphere of a dual-head radiation imaging device within its driving range. For the effectiveness in sensing, installation point was decided according to the finite element deformation analysis of the device model. The proposed sensor was implemented to the device, and then the result was evaluated by comparison with an optical tracker position data. In this method, attachable optical system were designed and implemented to the dedicated radiography system. From the attachment test relative deformation data of two orthogonal X-Ray tube and detector sets were obtained simultaneously by two image sensors attached on each of them. Laser spot orbits were obtained as a result, and were compared with optical tracker data results for verification. The proposed method significantly reduces costs and time spent for calibration process while satisfying micro scale precision requirements and it is applicable to other rotation mechanical system. Comprising devices costs much less than the manufacturing or purchasing a dedicated geometry phantoms, because this method only requires a low powered spot laser and a CMOS Camera plus additional optical devices.

     

Verification on spray simulation of a pintle injector for liquid rocket engine

The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.     

An incentive-compatible mechanism for efficient distribution of bulk contents on peer-to-peer networks

In recent years, the rapid growth of peer-to-peer (P2P) networks has provided a new paradigm for content distribution. To improve the efficiency of a P2P system, it is important to provide incentives for the peers to participate and contribute their resources. Various attempts have been made to reward/penalize peers by providing service differentiation based on a requesting peer’s history or reputation. However, in a truly distributed, non-cooperative environment, maintaining and preventing the untruthful revealing of such information within the community impose larger computation and communication overheads to the system. These problems are further magnified when large-volume contents are being distributed because of the length distribution processes and the update of history or reputation has to keep up with the distribution process. In this paper, we address the incentive provisioning problem for distribution of large-volume content in P2P networks, and present a “seeing-is-believing” incentive-compatible mechanism (protocol) in which a peer will decide how much resources will be assigned to which neighbors based on what it has experienced. The protocol applies a utility-based resource-trading concept where peers will maximize their contributions for a fair or better return, and we show that by adopting this protocol, the system will achieve Cournot Equilibrium. Furthermore, our protocol is lightweight, completely decentralized, and cheat-proof. Experimental results illustrate significant improvements on the distribution efficiency of our protocol over other adopted alternatives. Simon G. M. Koo is currently an Assistant Professor of Mathematics and Computer Science at the University of San Diego. H received his B. Eng. (Hons) in Information Engineering from the Chinese University of Hong Kong in 1997, M.S.E.E. from Polytechnic University, Brooklyn, in 1999, M.S. in Operations Research from Columbia University, NY, in 2001, and his Ph.D. from the School of Electrical and Computer Engineering, Purdue University, West Lafayette, in 2005. His current research include peer-to-peer networks, distributed mechanism design, performance modeling, and location-aware wireless applications. He is a member of IEEE, ACM and Sigma Xi. He is also listed in Who's Who of Emerging Leaders in 2007. C. S. George Lee received the B.S. and M.S. degrees in Electrical Engineering from Washington State University in 1973 and 1974, respectively, and the PhD degree from Purdue University, West Lafayette, IN in 1978.In 1978–1979, he taught at Purdue University, and in 1979–1985, at the University of Michigan. Since 1985, he has been with the School of Electrical and Computer Engineering, Purdue University, where he is currently Professor of Electrical and Computer Engineering.His current research focuses on humanoid robotics, distributed mobile robots, and neuro-fuzzy systems. He has authored or co-authored over 150 publications in these areas, in addition to 20 book chapters and two graduate textbooks. Dr. Lee was an IEEE Computer Society Distinguished Visitor in 1983–1986, the Organizer and Chairman of the 1988 NATO Advanced Research Workshop on Sensor-Based Robots: Algorithms and Architectures. He also served as Secretary and Vice-President for Technical Affairs of the IEEE Robotics and Automation Society (RAS) in 1988–1990 and 1990–1995, respectively. He was Program Chair of the 1996 IEEE International Conference on Robotics and Automation in Minneapolis, MN and the 1998 IEEE/RSJ International Conference on Intelligent Robots and Systems in Victoria, B.C., Canada. Dr. Lee served as an Administrative Committee member and a Distinguished Lecturer of the IEEE RAS, and the General Chair of the 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems held in Las Vegas, Nevada, on October 26–31, 2003. He currently serves as General Co-Chair of the 2006 IEEE International Conference on Robotics and Automation to be held in Orlando, Florida, on May 15–19, 2006. Dr. Lee has directed over 20 Ph.D. dissertations. He is an IEEE Fellow and a recipient of the IEEE Third Millennium Medal Award.     

Remote Switching of Elastic Movement of Decorated Ligand Nanostructures Controls the Adhesion-Regulated Polarization of Host Macrophages

Design of materials with remote switchability of the movement of decorated nanostructures presenting cell-adhesive Arg-Gly-Asp ligand can decipher dynamic cell-material interactions in decorated ligand nanostructures. In this study, the decoration of ligand-bearing gold nanoparticles (ligand-AuNPs) on the magnetic nanoparticle (MNP) with varying ligand-AuNP densities is demonstrated, which are flexibly coupled to substrate in various MNP densities to maintain constant macroscopic ligand density. Magnetic switching of upward (“Upper Mag”) or downward (“Lower Mag”) movement of varying ligand-AuNPs is shown via stretching and compression of the elastic linker, respectively. High ligand-AuNP densities promote macrophage adhesion-regulated M2 polarization that inhibits M1 polarization. Remote switching of downward movement (“Lower Mag”) of ligand-AuNPs facilitates macrophage adhesion-regulated M2 polarization, which is conversely suppressed by their upward movement (“Upper Mag”), both in vitro and in vivo. These findings are consistent with human primary macrophages. These results provide fundamental understanding into designing materials with decorated nanostructures in both high ligand-AuNP density and downward movement of the ligand-AuNPs toward the substrate to stimulate adhesion-regulated M2 polarization of macrophages while suppressing pro-inflammatory M1 polarization, thereby facilitating tissue-healing responses.     

Analysis and design of phase shift full bridge converter with series-connected two transformers

A new phase shift full bridge (PSFB) converter with series-connected two transformers is proposed. The proposed converter shows wide zero voltage switching (ZVS) ranges and no output inductor is needed since each transformer individually acts as an inductor or a transformer during different times of the switching cycle. The operational principle, large signal modeling, and design equations are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency for a 100W (5 V, 20 A) telecommunication on-board power supply.