Synthetic Micro-Doppler Signatures of Non-Stationary Channels for the Design of Human Activity Recognition Systems

The main aim of this dissertation is to generate synthetic micro-Doppler signatures and TV-MDSs to train the HACs. This is achieved by developing non-stationary fixed-tofixed (F2F) indoor channel models. Such models provide an in-depth understanding of the channel parameters that influence the micro-Doppler signatures and TV-MDSs. Hence, the proposed non-stationary channel models help to generate the micro-Doppler signatures and the TV-MDSs, which fit those of the collected measurement data. First, we start with a simple two-dimensional (2D) non-stationary F2F channel model with fixed and moving scatterers. Such a model assumes that the moving scatterers are moving in 2D geometry with simple time variant (TV) trajectories and they have the same height as the transmitter and the receiver antennas. The model of the Doppler shifts caused by the moving scatterers in 2D space is provided. The micro-Doppler signature of this model is explored by employing the spectrogram of which a closed-form expression is derived. Moreover, we demonstrate how the TV-MDSs can be computed from the spectrograms. The aforementioned model is extended to provide two three-dimensional (3D) nonstationary F2F channel models. Such models allow simulating the micro-Doppler signatures influenced by the 3D trajectories of human activities, such as walking and falling. Moreover, expressions of the trajectories of these human activities are also given. Approximate solutions of the spectrograms of these channels are provided by approximating the Doppler shifts caused by the human activities into linear piecewise functions of time. The impact of these activities on the micro-Doppler signatures and the TV-MDSs of the simulated channel models is explored. The work done in this dissertation is not limited to analyzing micro-Doppler signatures and the TV-MDSs of the simulated channel models, but also includes those of the measured channels. The channel-state-information (CSI) software tool installed on commercial-off-theshelf (COTS) devices is utilized to capture complex channel transfer function (CTF) data under the influence of human activities. To mitigate the TV phase distortions caused by the clock asynchronization between the transmitter and receiver stations, a back-to-back (B2B) connection is employed. Models of the measured CTF and its true phases are also shown. The true micro-Doppler signatures and TV-MDSs of the measured CTF are analyzed. The results showed that the CSI tool is reliable to validate the proposed channel models. This allows the micro-Doppler signatures and the TV-MDSs extracted from the data collected with this tool to be used to train the HACs.publishedVersio

Doppler Power Characteristics Obtained from Calibrated Channel State Information for Human Activity Recognition

Author's accepted manuscript.© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.acceptedVersio

A non-stationary relay-based 3D MIMO channel model with time-variant path gains for human activity recognition in indoor environments

Extensive research showed that the physiological response of human tissue to exposure to low-frequency electromagnetic fields is the induction of an electric current in the body segments. As a result, each segment of the human body behaves as a relay, which retransmits the radio-frequency (RF) signal. To investigate the impact of this phenomenon on the Doppler characteristics of the received RF signal, we introduce a new three-dimensional (3D) non-stationary channel model to describe the propagation phenomenon taking place in an indoor environment. Here, the indoor space is equipped with a multiple-input multiple-output (MIMO) system. A single person is moving in the indoor space and is modelled by a cluster of synchronized moving point scatterers, which behave as relays. We derive the time-variant (TV) channel transfer function (CTF) with TV path gains and TV path delays. The expression of the TV path gains is obtained from the instantaneous total received power at the receiver side. This TV total received power is expressed as the product of the TV power of the RF signal initially transmitted and received by a body segment and the TV received power of the redirected signal. These TV powers are determined according the free-space path-loss model. Also, a closed-form approximate solution to the spectrogram of the TVCTF is derived. Here, we analyse the effect of the motion of the person and the validity of the relay assumption on the spectrogram, the TV mean Doppler shift (MDS), and the TV Doppler shift (DS) of the TVCTF. Simulation results are presented to illustrate the proposed channel model.publishedVersio

A Trajectory-Driven 3D Channel Model for Human Activity Recognition

publishedVersio

MIMO Antenna Systems for Wireless Handheld Devices

Mobile communications have seen tremendous growths in the last decades in the form of smartphones, watches, wireless enabled Personal Digital Assistants (PDAs) and so on. The current and future wireless communication systems require high data-rate capabilities to support high speed needs of users in modern applications. Multiple-input multiple-output (MIMO) antenna systems have become the most promising candidate to support the increased data demand. Therefore, they have emerged as an integral part of the new 5G wireless standard. One key challenge regarding MIMO systems for the handheld is to be able to successfully accommodate multiple miniature platform integrated antennas within a small device. Associated with that challenge comes undesirable increased mutual coupling, efficiency and capacity degradation, human body effects etc. Innovative designs and techniques that can overcome these challenges for MIMO antennas for handheld devices are studied and developed in this dissertation. First, due to the overarching importance of MIMO system performance, a detailed methodology to evaluate MIMO antennas is developed and presented. Second, new isolation improvement techniques between MIMO antenna elements using electromagnetic band gap (EBG) and defected ground structures is investigated and developed. High isolation between MIMO elements leads to decreased correlation resulting in significant enhancement of MIMO system performance which was the driving factor for the above effort. The efficacy of including these structures in improving MIMO performance is evaluated and demonstrated through simulations and experiments. Third, printed dipole MIMO antennas with pattern/polarization diversity within a handheld device are designed and analyzed for operation in free-space and next to head and hand phantoms. Pattern and polarization diversity have been found to be proven techniques to enhance MIMO system capacity. Forth, various frequency and/or pattern reconfigurable MIMO antennas are investigated and developed. A novel frequency reconfigurable MIMO antenna array is designed, developed and tested that consists of four slot elements that are reconfigured using chip varactor diodes. The slots’ resonance frequency can be electronically tuned by varying the effective length of the resonant slot by integrating varactor diodes on the slots. The antenna was optimized for 5-GHz Wi-Fi operation with a relative frequency tuning range of 15% extending from 5.1 GHz to 5.9 GHz. MIMO performance analysis and effect of mobile phone components were also investigated demonstrating performance

On the influence of walking people on the Doppler spectral characteristics of indoor channels

acceptedVersionNivå

On the Influence of Walking People on the Doppler Spectral Characteristics of Indoor Channels

Author´s accepted manuscript© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.When modelling mobile radio channels with moving scatterers, it is generally assumed that the angles of departure (AODs), angles of arrival (AOAs), and the speed of the scatterers are time-invariant. However, this assumption is violated as the AODs and AOAs vary with the positions of the moving scatterers. Also, the speed of the moving scatterers might vary with time due to acceleration/deceleration. In this paper, we model the time-variant Doppler frequencies by taking into account the time-variant AODs, AOAs, and the variations of the speed of the moving scatterers. Furthermore, the complex channel gain of non-stationary single-input-single-output (SISO) fixed-to-fixed (F2F) indoor channels with moving and fixed scatterers is presented. The spectrogram of the complex channel gain using a Gaussian window is provided. The correctness of the analytical solutions is confirmed by simulations. The contribution of this paper paves the way towards the development of a passive in-home activity tracking system.acceptedVersio

Features of the species composition of pathogens suppurative inflammatory processes in patients of surgical department of ternopil university hospital

Nowadays the risk of purulent-inflammatory infections of postsurgical wounds is remained in the spotlight among health care practitioners. After all, postoperative complications are the reason for a longer and more expensive treatment of surgical diseases, and an increase in mortality. According to the WHO (2014) report, the resistance of microorganisms to antibiotics is one of the most significant problems and the most serious threats to human healt

Стратегічний підхід до управління закладом охорони здоров’я (на прикладі “Ain Shams Hospitals”)

The importance of strategic management in healthcare institutions lies in its ability to adapt to changes in the market environment and enhance the organization's competitiveness. The functional activities of the Ain Shams University Hospital (El-Demerdash) are focused on meeting the population's needs for qualified and accessible medical care, as well as integrating and effectively utilizing resources to achieve optimal outcomes in outpatient, polyclinic, and inpatient healthcare services. The implementation of the main management functions in the investigated medical institution, particularly strategic planning, forecasting, and planning, rests upon its administrative service. The organizational structure of the administrative service of the Ain Shams University Hospital (El-Demerdash) is focused on strategic development, effective utilization of financial, material-technical, informational, and organizational resources, as well as enhancing and strengthening the human resource potential of the institution. Effective analysis of the medical institution's functioning requires a significant amount of statistical, financial, and economic data. The main object of analysis is the costs that contribute to the cost of medical services provided by the institution. The secondary-level medical services provided by the institution are high-tech and resource-intensive. The lack of resources for providing this category of medical services is critical for delivering quality standardized medical care. The proportion of material and financial resources in the cost of services provided by a hospital offering secondary-level medical care is much higher than in primary care institutions. Therefore, the management staff of the medical institution needs to carry out continuous analysis, monitoring, and search for sources and means of resource provision. To streamline the planning processes of healthcare institutions, it is advisable to utilize technical, software, and other tools. In general, the process of strategic planning in healthcare institutions should be based on the concepts of program-target, functional, institutional (process-organizational), and situational approaches. The possibility of a comprehensive reorganization of the Egyptian’s healthcare system is determined by the need to consider a combination of factors: societal factors (lack of attention to health issues from both individuals and government structures; overall economic instability and lack of state funding for the sector; challenging socio-economic conditions) and sectoral factors (imperfections in the legislative framework for reforming medical institutions, particularly communal ownership; lack of a unified long-term reform program for the national healthcare system; shortage of trained professionals in the field of healthcare economics and management; lack of strategic planning skills among the managerial and administrative staff of medical institutions; slow and inert management of healthcare facilities; inefficient utilization of systemic resources in the sector). The healthcare reform in Egypt has initiated the planning and calculation of funding for healthcare institutions that provide secondary (specialized) and tertiary (highly specialized) inpatient medical care through state and local budgets based on a basic rate per treated case according to diagnostic-related groups. Significant cost savings can be achieved through optimization of the economic aspect of the investigated medical institution, specifically by replacing the head of the economic department with a manager responsible for broader economic duties. By analyzing the vehicle fleet and available heating area, conclusions can also be drawn regarding the feasibility of adjusting the functional load of certain support staff and hospital services.The explanatory note to the master's qualification work consists of 68 pages, 2 illustrations, 7 tables. The structure of the work consists of an introduction, four chapters, conclusions to each section, general conclusions, a list of sources used, which consists of 19 items and appendices. The work is devoted to develop theoretical foundations and practical recommendations for improving the application of a strategic approach in managing a healthcare institution (“Ain Shams Hospitals” case study). To implement the tasks in the study, the following research methods were used: analysis of scientific sources, comparative analysis, statistical method, method of own observations, method of generalization.INTRODUCTION. CHAPTER 1. THEORETICAL AND METHODOLOGICAL FOUNDATIONS OF APPLYING THE STRATEGIC APPROACH TO MANAGING HEALTHCARE.1.1. The Essence and Features of Applying the Strategic Approach to Managing Healthcare Institutions.1.2. Forms and Methods of Strategic Management in Healthcare Institutions. Conclusions for Chapter 1. CHAPTER 2: SYSTEM ANALYSIS AND EVALUATION OF APPLYING THE STRATEGIC APPROACH TO MANAGING AIN SHAMS HOSPITAL (EL-DEMERDASH). 2.1. General information about the hospital. 2.2. Analysis of the Activities of the Investigated Healthcare Institution in the Context of Meeting the Healthcare Requirements of the District Population. 2.3. Evaluation of Institutional and Resource Provision for Applying a System Approach to Managing the Investigated Medical Institution. 2.4. Analysis of the Effectiveness of Applying Strategic Management Tools in "Ain Shams Hospitals. Conclusions for Chapter 2. CHAPTER 3. DIRECTIONS FOR IMPROVING THE IMPLEMENTATION OF THE STRATEGIC APPROACH TO MANAGING THE HEALTHCARE INSTITUTION. 3.1. Formation of Hospital Districts as a Strategic Direction for Reforming the Activities of Healthcare Institutions. 3.2. Enhancement of Resource Provision for Strategic Management of the Medical Institution. Conclusions for Chapter 3. CHAPTER 4. LABOR PROTECTION AND SAFETY IN EMERGENCIES. 4.1. Instruction general sanitary and hygienic requirements to cleaning, care on the equipment of drugstores. 4.2. Emergency plan at workplace. CONCLUSION. REFERENCES. APPENDICES