Multiple Person Localization Based on Their Vital Sign Detection Using UWB Sensor

In the past period, great efforts have been made to develop methods for through an obstacle detection of human vital signs such as breathing or heart beating. For that purpose, ultra-wideband (UWB) radars operating in the frequency band DC-5 GHz can be used as a proper tool. The basic principle of respiratory motion detection consists in the identification of radar signal components possessing a significant power in the frequency band 0.2–0.7 Hz (frequency band of human respiratory rate) corresponding to a constant bistatic range between the target and radar. To tackle the task of detecting respiratory motion, a variety of methods have been developed. However, the problem of person localization based on his or her respiratory motion detection has not been studied deeply. In order to fill this gap, an approach for multiple person localization based on the detection of their respiratory motion will be introduced in this chapter

The crossing numbers of join products of paths with three graphs of order five

The main aim of this paper is to give the crossing number of the join product $G^∗ + P_n$ for the disconnected graph G^∗ of order five consisting of the complete graph $K_4$ and one isolated vertex, where $P_n$ is the path on n vertices. The proofs are done with the help of a lot of well-known exact values for the crossing numbers of the join products of subgraphs of the graph $G^∗$ with the paths. Finally, by adding new edges to the graph $G^∗$, we are able to obtain the crossing numbers of the join products of two other graphs with the path $P_n$

Multiple moving person tracking by UWB sensors: the effect of mutual shielding persons and methods reducing its impacts

Abstract Ultra-wideband (UWB) radars are sensors allowing to track people in critical environments and situations. The results reached by single UWB sensors for such applications have shown that they are able to detect and track a person very well in a single person scenario. However, in multiple moving person scenarios, the ability of a single UWB sensor to detect several persons is usually significantly reduced. This is caused by a mutual shielding among people. In this paper, we will deal with the mutual shielding effect and its impacts, as well as with the methods of improving multiple moving person tracking by UWB radars. Firstly, we will provide a comprehensive description of the mutual shielding effect. Then, based on its analyses, we will state three complementary approaches created by the authors of this paper to reduce its impacts. They include an enhancement of the low-level echo of the targets, radar antenna array positioning at a convenient height, UWB sensor network application and, finally, their mutual combinations. The properties of those approaches will be demonstrated by two experimental measurements aimed at through wall tracking of two and three people, respectively. The results obtained in the experiments will illustrate the mutual shielding effect and the potential of the methods we have proposed to reduce its impacts

UWB Radar Signal Processing for Localization of Persons with the Changing Nature of Their Movement

In the last decade, it has been shown that short-range ultra-wide band radars (sensors) can provide the efficient solution for human being localization for line-of-sight and non-line-of-sight scenarios. To localize people correctly using this technology, the corresponding detection and localization methods have to be selected according to the nature of person motion state. In this respect, two basic kinds of persons can be identified. They are so-called moving and static persons. In this paper, we will introduce a radar signal processing procedure allowing a joint detection and localization of moving and static persons. Good performance properties of this procedure will be confirmed by its application for an experimental scenario represented by a through-the-wall detection and localization of a single person with changing nature of his/her movement

Through-the-Wall Localization of a Moving Target by Two Independent Ultra Wideband (UWB) Radar Systems

In the case of through-the-wall localization of moving targets by ultra wideband (UWB) radars, there are applications in which handheld sensors equipped only with one transmitting and two receiving antennas are applied. Sometimes, the radar using such a small antenna array is not able to localize the target with the required accuracy. With a view to improve through-the-wall target localization, cooperative positioning based on a fusion of data retrieved from two independent radar systems can be used. In this paper, the novel method of the cooperative localization referred to as joining intersections of the ellipses is introduced. This method is based on a geometrical interpretation of target localization where the target position is estimated using a properly created cluster of the ellipse intersections representing potential positions of the target. The performance of the proposed method is compared with the direct calculation method and two alternative methods of cooperative localization using data obtained by measurements with the M-sequence UWB radars. The direct calculation method is applied for the target localization by particular radar systems. As alternative methods of cooperative localization, the arithmetic average of the target coordinates estimated by two single independent UWB radars and the Taylor series method is considered

Numerical Investigation of the Time Discretization Impact on the Accuracy of a Point Target Localization by UWB Radar

UWB radar technologies enable localization of moving persons (targets) situated behind nonmetallic obstacles. Under exact knowledge of the propagation times, from the transmitting to the receiving antennas, of the radar emitted electromagnetic wave (time of arrival, TOA), a highly accurate target localization can be achieved. Since TOA estimates only are available, their use for target localization may result in a sizeable target localization error. In this paper we study the influence of TOA quantization on the point target localization accuracy using numerical simulation methods

Numerical Investigation of the Time Discretization Impact on the Accuracy of a Point Target Localization by UWB Radar

UWB radar technologies enable localization of moving persons (targets) situated behind nonmetallic obstacles. Under exact knowledge of the propagation times, from the transmitting to the receiving antennas, of the radar emitted electromagnetic wave (time of arrival, TOA), a highly accurate target localization can be achieved. Since TOA estimates only are available, their use for target localization may result in a sizeable target localization error. In this paper we study the influence of TOA quantization on the point target localization accuracy using numerical simulation methods

The Effect of Iron Content on Microstructure and Porosity of Secondary AlSi7Mg0.3 Cast Alloy

In the present study, microstructure and porosity of AlSi7Mg0.3 cast alloy including various amounts (0.123; 0.454 and 0.655 wt. %) of iron were investigated. The alloys were produced as secondary (scrap-based - recycled). Iron leads to the formation of complex intermetallic phases during solidification, and how these phases can adversely affect mechanical properties, especially ductility, and also lead to the formation of excessive shrinkage porosity defects in castings. In order to determine the effect of iron addition to AlSi7Mg0.3 alloy, optical and SEM microscopy with EDX were used for microstructural examinations. Image analysis was conducted in order to determine effect of the Fe content on phases and porosity. It was found that increasing Fe content from 0.123 to 0.655 wt. % has no effect on SDAS but the morphology of Al-Si eutectic became finer. From EDX examinations, different Fe-based intermetallic phases (β-Al5FeSi and α-Al15(FeMg)3Si2) were observed. It was also observed that as Fe content increased, α-Al15(FeMg)3Si2 phases was transformed into Al5FeSi and the size and the number of Al5FeSi phases increases. The image analysis results revealed that porosity values were by increasing Fe content increased too. We can to predict, that with the increasing amount of Fe decreasing the mechanical properties (first of all) ductility (through long β-Al5FeSi intermetallic and high porosity)

Employing various metallography methods at high temperature alloy fatigue tests evaluation

. Microstructures of superalloys have dramatically changed throughout the years, as modern technology of its casting or forging has become more sophisticated. The first superalloys have polyedric microstructure consisting of gamma solid solution, some fraction of gamma prime and of course grain boundaries. As demands on higher performance of aero jet engine increases, the changes in superalloys microstructure become more significant. A further step in microstructure evolution was directionally solidified alloys with columnar gamma prime particles. The latest microstructures are mostly monocrystalline, oriented in [001] direction of FCC gamma matrix. All microstructure changes bring necessity of proper preparation and evaluation of microstructure. Except for the already mentioned structures have gamma double prime and various carbides form can be seen. These structural parameters have mainly positive influence on important mechanical properties of superalloys. The paper deals with a microstructural evaluation of both groups of alloys – cast and as well as wrought. Microstructure evaluation helps to describe mechanism at various loading and failure of progressive superalloys. Such an example where microstructure evaluation is employed is fractography of failure surfaces after fatigue tests, which are examples of metallography evaluation described in this paper as a secondary objective