[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.

Electromagnetic thermography and optical thermography are both important non-destructive testing (NDT) methods that have been widely used in the fields of modern aerospace, renewable energy, nuclear industry, etc. The excitation modes are crucial whose performances have a decisive effect on the detection results. Previous studies mainly focused on the physics mechanism, applications, and signal processing algorithms. However, the instrument configuration is rarely presented. This paper is to introduces the recently designed excitation sources of electromagnetic thermography and optical thermography detection systems, respectively. These instruments involved L-shaped and Shuttle-shaped sensor structures for electromagnetic thermography and multi-modes excitation for optical thermography. Besides, the topologies and operating principles are shown in detail. Experimental results are carried out to verify the practicability and reliability of the proposed systems.

/pdf/instrumental-configuration-of-electromagnetic-thermography-4ai8932w3o.pdf

Instrumental Configuration of Electromagnetic Thermography and Optical Thermography

When trains pass through damaged switch rails, rail head damage will change wheel–rail contact states from rolling frictions to unsteady contacts, which will result in impact vibrations and threaten structural safeties. In addition, under approaching and moving away rolling contact excitations and complex wheel–rail contacts, the non-stationary vibrations make it difficult to extract and analyze impact vibrations. In view of the above problems, this paper proposes a variational-mode-decomposition (VMD)-spectral-subtraction (SS)-based impact vibration extraction method. Firstly, the time domain feature analysis method is applied to calculate the time moments that the wheels pass joints, and to correct vehicle velocities. This can help estimate and confine impact vibration distribution ranges. Then, the stationary intrinsic mode function (IMF) components of the impact vibration are decomposed and analyzed with the VMD method. Finally, impact vibrations are further filtered with the SS method. For rail head damage with different dimensions, under different velocity experiments, the frequency and amplitude features of the impact vibrations are analyzed. Experimental results show that, in low-velocity scenarios, the proposed VMD–SS–based method can extract impact vibrations, the frequency features are mainly concentrated in 3500–5000 Hz, and the frequency and peak-to-peak features increase with the increase in excitation velocities.

/pdf/wheel-rail-contact-induced-impact-vibration-analysis-for-3gzwdntg.pdf

Wheel-Rail Contact-Induced Impact Vibration Analysis for Switch Rails Based on the VMD-SS Method

The principle of the inductance displacement sensor on optical aperture synthesis telescope is given with a measure- ment of mutual inductance to deduce the axial distance. It illustrates an effective modelling and calculation method based on Partial Element Equivalent Circuit (PEEC). PEEC is the method to calculate mutual inductances between coils utilizing partial parameter concept. Simulation for the change of mutual inductances is done which is prepared for the next step work.

A study of inductance displacement sensor on optical aperture synthesistelescope

Stress measurement and evaluation of ferromagnetic components using electromagnetic nondestructive testing (ENDT) are affected by the microstructure properties of the material, such as inhomogeneity and anisotropy. This leads to magnetic induction sensitivity in the variety of both the stress and microstructure. To address this challenge, a hybrid magnetic sensing structure for measuring eddy current (EC), alternating electromagnetic (EM) field, Barkhausen noise, and incremental permeability signals is designed and instrumented. Additionally, a stress detection verification test for oriented silicon steel samples is carried out, and a comparison with commercial instruments in terms of sensitivity and repeatability is performed. The results show that the proposed sensor has advantages in detection repeatability, good sensitivity as well as high signal-to-noise (SNR) for MBN features, which brings potential in stress characterization and assessment.

Stress Measurement of Ferromagnetic Materials Using Hybrid Magnetic Sensing

In this article, the frequency sensitivity of the Coil-interdigital electrode (IDE) sensor in different integrated topologies is studied. In particular, the expression of the resonance frequency of the Coil-IDE sensor both in series and parallel topological structure is derived. The sensitivity of frequency to IDE capacitance was analyzed, and two new results can be found 1) due to the existence of coil winding capacitance and grounding capacitance, the Coil-IDE topology circuit has been changed, which causes the Coil-IDE parallel topology structure has a higher frequency sensitivity than series and 2) not only the topology structure but also the parameters such as coil inductance and IDE capacitance have the regulatory effect on the frequency sensitivity. After analysis, an experiment of a Coil-IDE humidity sensor was applied to verify the presented results. The parallel frequency of the Coil-IDE parallel structure having a higher sensitivity was confirmed. The error of the proposed formula predicting the regulatory effect of parameters on frequency sensitivity was discussed. The error is as low as 7.57%, which shows the beneficial aspect of the integrated design of Coil-IDE sensor both in topological structure and parameters.

Gui Yun Tian

Papers

Instrumental Configuration of Electromagnetic Thermography and Optical Thermography

Wheel-Rail Contact-Induced Impact Vibration Analysis for Switch Rails Based on the VMD-SS Method

A study of inductance displacement sensor on optical aperture synthesistelescope

Stress Measurement of Ferromagnetic Materials Using Hybrid Magnetic Sensing

Frequency Sensitivity Analysis of Coil-IDE Resonance Topology Circuit and Its Humidity Sensor Applications