Photoplethysmography and its application in clinical physiological measurement

Photoplethysmography (PPG) is an uncomplicated and inexpensive optical measurement method that is often used for heart rate monitoring purposes. PPG is a non-invasive technology that uses a light source and a photodetector at the surface of skin to measure the volumetric variations of blood circulation. Recently, there has been much interest from numerous researchers around the globe to extract further valuable information from the PPG signal in addition to heart rate estimation and pulse oxymetry readings. PPG signal's second derivative wave contains important health-related information. Thus, analysis of this waveform can help researchers and clinicians to evaluate various cardiovascular-related diseases such as atherosclerosis and arterial stiffness. Moreover, investigating the second derivative wave of PPG signal can also assist in early detection and diagnosis of various cardiovascular illnesses that may possibly appear later in life. For early recognition and analysis of such illnesses, continuous and real-time monitoring is an important approach that has been enabled by the latest technological advances in sensor technology and wireless communications. The aim of this article is to briefly consider some of the current developments and challenges of wearable PPG-based monitoring technologies and then to discuss some of the potential applications of this technology in clinical settings.

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A review on wearable photoplethysmography sensors and their potential future applications in health care.

Water pipeline leakage detection is still an important issue, particularly for the development of smart cities. Thus, this paper reviews water pipeline leakage detection techniques, which can be classified into three different categories, namely, software-based, hardware-based, and conventional methods. We compare the advantages and disadvantages for all the methods in the groups and thoroughly discuss the hardware-based method, which is our focus. Specifications on water pipeline testbeds used in the previous works are also highlighted. Since many recent techniques are based on accelerometer or vibration sensors, a comparative study that includes the cost and accuracy in identifying the pipeline leaks is presented. The theoretical computation of the vibration induced from our water pipeline testbed is also demonstrated and compared with the actual vibration data collected from the experimental works using three different sensors, namely, MPU6050, MMA7361, and ADXL335.

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A Review of Vibration Detection Methods Using Accelerometer Sensors for Water Pipeline Leakage

Photoplethysmography has been routinely used for health monitoring in the past decades. Even though in daily medical practice, photoplethysmograms (PPGs) are recorded at red and near infra-red light (rPPGs), during the last decade, PPGs obtained at green light (gPPGs) have been widely used in wearable devices, such as wristbands and smartwatches, thus providing highly usable and accessible daily health monitoring. It is well recognized that PPG signals obtained at NIR light contain sufficient information about a person's health; furthermore, they are well-studied and highly complex. By contrast, green light PPGs have not been sufficiently studied; thus, it is not clear whether the provided information is as valuable as that obtained by rPPGs, as green light photoplethysmography is formed at papillary dermis and higher skin levels. However, the gPPG signal is recognized to be more robust to motion artifacts compared with rPPGs. As rPPG dynamics has been recognized as chaotic, this study is aimed at investigating the properties of gPPGs and compare them with those of rPPGs to determine whether gPPG dynamics is chaotic as well. The motivation for this question was not only to investigate whether gPPGs can be used for the same range of applications as rPPGs but also to obtain insight into whether the complexity of rPPGs is solely due to processes in deeper layers of the tissue or it is influenced by the higher-skin layers processes that create gPPGs. The obtained results demonstrated that gPPGs, as well as rPPGs, are chaotic, which implies that processes in the upper layers create chaos in PPG data, whereas the contribution of arterial blood volume changes is not completely clear.

Photoplethysmogram at green light: Where does chaos arise from?

Forest fires are a significant threat to the ecological system’s stability. Several attempts have been made to detect forest fires using a variety of approaches, including optical fire sensors, and satellite-based technologies, all of which have been unsuccessful. In today’s world, research on flying ad hoc networks (FANETs) is a thriving field and can be used successfully. This paper describes a unique clustering approach that identifies the presence of a fire zone in a forest and transfers all sensed data to a base station as soon as feasible via wireless communication. The fire department takes the required steps to prevent the spread of the fire. It is proposed in this study that an efficient clustering approach be used to deal with routing and energy challenges to extend the lifetime of an unmanned aerial vehicle (UAV) in case of forest fires. Due to the restricted energy and high mobility, this directly impacts the flying duration and routing of FANET nodes. As a result, it is vital to enhance the lifetime of wireless sensor networks (WSNs) to maintain high system availability. Our proposed algorithm EE-SS regulates the energy usage of nodes while taking into account the features of a disaster region and other factors. For firefighting, sensor nodes are placed throughout the forest zone to collect essential data points for identifying forest fires and dividing them into distinct clusters. All of the sensor nodes in the cluster communicate their packets to the base station continually through the cluster head. When FANET nodes communicate with one another, their transmission range is constantly adjusted to meet their operating requirements. This paper examines the existing clustering techniques for forest fire detection approaches restricted to wireless sensor networks and their limitations. Our newly designed algorithm chooses the most optimum cluster heads (CHs) based on their fitness, reducing the routing overhead and increasing the system’s efficiency. Our proposed method results from simulations are compared with the existing approaches such as LEACH, LEACH-C, PSO-HAS, and SEED. The evaluation is carried out concerning overall energy usage, residual energy, the count of live nodes, the network lifetime, and the time it takes to build a cluster compared to other approaches. As a result, our proposed EE-SS algorithm outperforms all the considered state-of-art algorithms.

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Wildfire Monitoring Based on Energy Efficient Clustering Approach for FANETS

Providing an identity solution is essential for a reliable blockchain-based land registry system. A secure, privacy-preserving, and efficient identity solution is essential but challenging. This paper examines the current literature and provides a systematic literature review in three stages based on the three research questions (RQ) that show the assessment and interpretation process step by step. Based on the parameters and RQ specified in the research methodology section, a total of 43 primary articles have been selected from the 251 articles extracted from various scientific databases. The majority of these articles are concerned with evaluating the existing self-sovereign identity (SSI) solutions and their role in the blockchain-based land registry system to address the compliance issues in the existing SSI solutions with SSI principles and find the best possible SSI solution to address the identity problems in the land registry. The existing digital identity solutions cannot handle the requirements of the identity principle and are prone to various limitations like centralization and dependency on third parties that further augment the chance of security threats. SSI has been designed to overcome these limitations and provide a secure, reliable, and efficient identity solution that gives complete control to the users over their personal identity information (PII). This paper reviews the existing SSI solutions, evaluates them based on the SSI principles, and comes up with the best possible SSI solution for a blockchain-based land registry system. It further provides a detailed investigation of each SSI solution to present its functionalities and limitations for further improvement.

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Self-Sovereign Identity Solution for Blockchain-Based Land Registry System: A Comparison

The photoplethysmography (PPG) is a non invasive technique in measuring blood volume change This technique is cheap and very convenient to use with the PPG device being applied to patients' fingers In this study the aging index of the second derivative method of PPG (SDPPG-AI) is used for monitoring the arterial condition The vascular response in resistance arteries plays an important role in blood pressure and the SDPPG-AI can be used to evaluate the vascular aging and screening of atherosclerotic patients In this study the correlation between premature vascular aging and atherosclerosis of eight atherosclerotic patients is examined Results showed that the patients recorded higher index of vascular aging compared to eight healthy subjects

Second derivatives of photoplethysmography (PPG) for estimating vascular aging of atherosclerotic patients

Providing a system user with a unique and secure identity is a prerequisite for authentication and authorization aspects of a security system. It is generally understood that the existing digital identity systems store the identity details in centralized databases, and users store the identity details in centralized databases in which users do not have any control over them. These vulnerabilities in the traditional digital identities make them susceptible to various malicious assaults and modifications. Users’ personally identifiable information (PII) may leak through these identity solutions that can consequently affect other applications being used by the users, and they have no control over them. Land registration is a major domain of governance that defines civilians’ well-being and needs to be handled properly to avoid conflict and to support Environmental Sustainability. These traditional land registry applications also lack identity parameters due to weaknesses in identity solutions. A secure and reliable digital identity solution is the need of the hour. Self-sovereign identity (SSI), a new concept, is becoming more popular as a secure and reliable identity solution for users based on identity principles. SSI provides users with a way to control their personal information and consent for it to be used in various ways. In addition, the user’s identity details are stored in a decentralized manner, which helps to overcome the problems with digital identity solutions. This article reviews existing SSI solutions and analyzes them using SSI principles. It also assesses the SSI components required for constructing SSI frameworks that adhere to the SSI principles. Furthermore, it defines the procedures for establishing an SSI ecosystem, explores the laws governing digital identity that governments have adopted, and identifies SSI applications in several fields. Finally, a review of SSI applications in the domain of land registry systems is given in order to propose an SSI-based land registry framework for a secure and reliable land registry system.

https://www.mdpi.com/2071-1050/14/9/5400/pdf?version=1651303975

Land Registry Framework Based on Self-Sovereign Identity (SSI) for Environmental Sustainability

Non-invasive studies using photoplethysmography(PPG) have great potential to be used for a wide range of clinical measurements. In this study, we propose that arterial stiffness may be measured using an approach based on a pulse contour analysis of PPG. The area under the curve (auc-PPG) was compared between patients with HbA1c<8% (Group 1) and HbA1c>10% (Group 2). The auc-PPG was significantly higher in diabetic subjects with HbA1c<8% than in those with HbA1c>10%. To investigate the association between the first and repeated measurements, a paired t-test was conducted. There was no significant difference in auc-PPG between the first and repeated measurements for either group of diabetic patients. These results indicated that the arterial stiffness in patients with different levels of HbA1c can be approximated using auc-PPG. [Usman S, Reaz MBI, Ali MAM. Repeated measurement analysis of the area under the curve of photoplethysmogram among diabetic patients. Life Sci J 2013;10(4):532-539]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 69

Repeated measurement analysis of the area under the curve of photoplethysmogram among diabetic patients

Diabetes mellitus is a group of metabolic diseases associated with the production and/or reaction of insulin leading to hyperglycemia. Glycated hemoglobin (HbA1c) level is generally measured for hyperglycemia. Hyperglycemia and the duration of having diabetes are two factors that contribute to developing complications. A trend of increasing arterial stiffness has been identified in Type 2 diabetes. Photoplethysmograph (PPG) pulse wave provides a ‘window’ into the properties of small arteries whereas stiffening of these arteries will alter the PPG waveform. In this research, the potential of PPG in discriminating type 2 diabetic patients between two different levels of HbA1c has been investigated (diabetic patient with HbA1c 10% as unhealthy group). Contour analysis of PPG signal and second derivative photoplethysmograph (SDPPG) techniques have been used to identify the feasible parameter for this research. From this study, it shows that there is no significant difference for both group of diabetic patient for ratio of b/a, which extracted from SDPPG. The mean ratio for controlled group is 0.5692 and 0.6067 for unhealthy group, p=0.180. Other than that, the results show that there is a statistical significant different for the some variables extracted.

Sahnius Usman

Papers

Self-Sovereign Identity Solution for Blockchain-Based Land Registry System: A Comparison

Second derivatives of photoplethysmography (PPG) for estimating vascular aging of atherosclerotic patients

Land Registry Framework Based on Self-Sovereign Identity (SSI) for Environmental Sustainability

Repeated measurement analysis of the area under the curve of photoplethysmogram among diabetic patients

Second Derivative and Contour Analysis of PPG for Diabetic Patients