[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

A scheme is developed for classifying the types of motion perceived by a humanlike robot. It is assumed that the robot receives visual images of the scene using a perspective system model. Equations, theorems, concepts, clues, etc., relating the objects, their positions, and their motion to their images on the focal plane are presented. >

http://ieeexplore.ieee.org/iel2/815/3148/00100651.pdf

Robot vision

/pdf/remote-sensing-of-the-environment-4yfxjaaswe.pdf

Remote sensing of the environment

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.

/pdf/principles-of-physical-layer-security-in-multiuser-wireless-3w4jvwpgy4.pdf

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

In this paper, we propose a unified framework to generate a pleasant and high-quality street-view panorama by stitching multiple panoramic images captured from the cameras mounted on the mobile platform. Our proposed framework is comprised of four major steps: image warping, color correction, optimal seam line detection and image blending. Since the input images are captured without a precisely common projection center from the scenes with the depth differences with respect to the cameras to different extents, such images cannot be precisely aligned in geometry. Therefore, an efficient image warping method based on the dense optical flow field is proposed to greatly suppress the influence of large geometric misalignment at first. Then, to lessen the influence of photometric inconsistencies caused by the illumination variations and different exposure settings, we propose an efficient color correction algorithm via matching extreme points of histograms to greatly decrease color differences between warped images. After that, the optimal seam lines between adjacent input images are detected via the graph cut energy minimization framework. At last, the Laplacian pyramid blending algorithm is applied to further eliminate the stitching artifacts along the optimal seam lines. Experimental results on a large set of challenging street-view panoramic images captured form the real world illustrate that the proposed system is capable of creating high-quality panoramas.

A Unified Framework for Street-View Panorama Stitching.

THz time-domain spectroscopy has evolved as a noncontact, safe, and efficient technique for paper characterization Our previous work adopted peak amplitude and delay time as features to determine paper basis weight using terahertz time-domain spectroscopy However, peak amplitude and delay time tend to suffer from noises, resulting in degradation of accuracy and robustness This paper proposes a noise-robust phase-shift based method to enhance measurements of paper basis weight Based on Fresnel Formulae, the physical relationship between phase shift and paper basis weight is formulated theoretically neglecting multiple reflections in the case of normal incidence The established formulation indicates that phase shift correlates linearly with paper basis weight intrinsically Subsequently, paper sheets were stacked to fabricate the samples with different basis weights, and experimental results verified the developed mathematical formulation Moreover, a comparison was made between phase shift, peak amplitude, and delay time with respect to linearity, accuracy, and noise robustness The results show that phase shift is superior to the others

/pdf/enhanced-measurement-of-paper-basis-weight-using-phase-shift-53mlral2gu.pdf

Enhanced Measurement of Paper Basis Weight Using Phase Shift in Terahertz Time-Domain Spectroscopy

In this paper, a new triple-octahedron variable-geometry truss manipulator is presented. Its inverse kinematic solutions in closed form are studied. An input-output displacement equation in one output variable is derived. The solution procedure is given in detail. A numerical example is illustrated.

/pdf/inverse-kinematic-analysis-for-triple-octahedron-variable-2sll3h10sh.pdf

Inverse kinematic analysis for triple octahedron variable geometry truss manipulators

Considering the global aging of pipelines and demand for new ones in more and more hostile environments, in-line inspection (ILI) based on the Non-Destructive Testing(NDT) was essential for pipeline operating company to protect their asset efficiently. This paper reviewed kinds of state of the art of ILI techniques and equipments, including geometry pig (GP), magnetic flux leakage pig (MFL PIG), ultrasonic pig (UT PIG), electromagnetic acoustic pig (EMAT PIG), eddy current pig (EC PIG), integrated function pig and specific function pig. Through the review of kinds of techniques, different approaches were compared, challenges and problems were highlighted and future research and direction was suggested.

/pdf/comparative-analysis-of-in-line-inspection-equipments-and-2o9rpikqlu.pdf

Comparative Analysis of In-line Inspection Equipments and Technologies

In this work, an improved model-based method is proposed to infer the thickness of up to four layers of coatings on metallic substrates using reflected terahertz pulse echoes. Firstly, an analytical model is formulated based on Rouard method. Considering that the surface and the interfaces of coatings are basically rough rather than smooth, the roughness of surface and interfaces is taken into account with Kirchhoff approximation due to scattering when developing the model. The samples with multilayer coatings are prepared by stacking paper sheets on a metallic substrate. Through simulations, it is found that the reflected terahertz signals decrease significantly due to the scattering with an increase of surface roughness, whereas the interface roughness has slight effect on the reflected terahertz signals. Finally, experiments are carried out to validate the formulated model and the proposed improved method. By considering the effect of surface and interfaces roughness, the residuals reduce obviously and the measurement errors decrease to 1% or less.

Noncontact Thickness Measurement of Multilayer Coatings on Metallic Substrate Using Pulsed Terahertz Technology

This paper presents the development of a newly designed wireless piezoelectric PZT sensor platform for distributed large-scale structure health monitoring, where real-time data acquisition with high sampling rate up to 12.5 Msps sample per second and distributed lamb-wave data processing are implemented. In the proposed wireless PZT network, a set of PZT transducers are deployed at the surface of the structure, a lamb-wave is excited, and its propagation characteristics within the structure are inspected to identify damages. The developed wireless node platform features a digital signal processor DSP of TMS320F28335 and an improved IEEE 802.15.4 wireless data transducer RF233 with up to 2 Mbps data rate. Each node supports up to 8 PZT transducers, one of which works as the actuator generating the lamb-wave at an arbitrary frequency, while the responding vibrations at other PZT sensors are sensed simultaneously. In addition to hardware, embedded signal processing and distributed data processing algorithm are designed as the intelligent “brain” of the proposed wireless monitoring network to extract features of the PZT signals, so that the data transmitted over the wireless link can be reduced significantly.

Gui Yun Tian

Papers

Enhanced Measurement of Paper Basis Weight Using Phase Shift in Terahertz Time-Domain Spectroscopy

Inverse kinematic analysis for triple octahedron variable geometry truss manipulators

Comparative Analysis of In-line Inspection Equipments and Technologies

Noncontact Thickness Measurement of Multilayer Coatings on Metallic Substrate Using Pulsed Terahertz Technology

High-Performance Wireless Piezoelectric Sensor Network for Distributed Structural Health Monitoring