Waltenegus Dargie

Waltenegus Dargie
Technische Universität Dresden | TUD · Institute of Systems Architecture

Doctor of Philosophy
Working on Indoor Localization. Self-navigation of mobile robots. Joint deployment of UAVs, mobile robots, WSN.

About

175
Publications
53,925
Reads
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Introduction
I am currently working on two topics: Indoor localisation of mobile robots and Characterisation of air-to-air and air-to-ground links interfacing wireless sensor networks and Unmanned Aerial Vehicles. These systems will be useful for monitoring extensive, inaccessible, and dangerous areas. For the first topic we investigate the usefulness of Hidden Markov Models, Kalman Filters, and Particle Filters to localise mobile robots based on the analysis of data from UWB and inertial sensors.
Additional affiliations
November 2005 - June 2010
Technische Universität Dresden
Position
  • Researcher
September 2002 - December 2005
Universität Kassel
Position
  • Researcher
March 2001 - April 2002
Fraunhofer Institute for Experimental Software Engineering IESE
Position
  • Research Assistant
Education
September 2002 - June 2006
Technische Universität Dresden
Field of study
  • Computer Engineering
October 2000 - July 2002
Technische Universität Kaiserslautern
Field of study
  • Electrical Engineering
September 1994 - July 1997
Nazareth Technical College
Field of study
  • Electrical and Electronics Technology

Publications

Publications (175)
Book
Full-text available
Sensors have always been essential elements of all intelligent systems. Biological systems, for example, are equipped with millions of simple and unobtrusive yet indispensable sensors. Indeed the trillions nerve cells populating the cerebral cortex of a human brain are essentially sensors, for they responds to and generate action potentials in the...
Conference Paper
Full-text available
As the global IP traffic and its demand for computation increase in a rapid and sustained manner, processor, server, and network architectures are also undergoing a considerable evolution. Two of the manifestations of this evolution are the integration of a large number of computing nodes in a single server and the interconnection of many servers v...
Article
Full-text available
Quantitatively estimating the relationship between the workload and the corresponding power consumption of a multicore processor is an essential step towards achieving energy proportional computing. Most existing and proposed approaches use Performance Monitoring Counters (Hardware Monitoring Counters) for this task. In this paper we propose a comp...
Conference Paper
Full-text available
Wireless electrocardiograms are useful for several practical applications in the healthcare domain. However, their usefulness is often limited by the quality of data that can be extracted from them. One of the main factors affecting the quality of ECG data is the inclusion of movement induced artefacts. In this paper we propose an adaptive filter t...
Article
Full-text available
Self-organizing protocols and algorithms in wireless sensor networks rely on knowledge of the topology of the network they manage. In most practical cases, establishing the topology prior to actual deployment is not possible, as the exact placement of nodes and the existence of a reliable link between any two individual nodes cannot be guaranteed....
Chapter
Gas accidents frequently turn industrial or civil structures into extremely dangerous environments. Disasters like the Ahrtal flood in summer 2021 destroy infrastructures such as the gas grid and the power grid, so that people loose control and suddenly find themselves confronted with explosions, suffocation, and death. This paper presents a case s...
Conference Paper
The increasing population size of the elderly is fostering the development of telehealth and assisted living systems. In this respect, monitoring vital biophysical conditions using wireless devices, such as the wireless electrocardiogram (WECG), plays a pivotal role in telemonitoring. However, the freedom of movement brings with it motion artifacts...
Preprint
div>Self-organizing protocols and algorithms require knowledge of the underlying topology of the network. The topology can be represented by a graph or an adjacency matrix. In most practical cases, establishing the topology prior to a deployment is not possible because the exact placement of nodes and the existence of a reliable link between any tw...
Preprint
Full-text available
div>Self-organizing protocols and algorithms require knowledge of the underlying topology of the network. The topology can be represented by a graph or an adjacency matrix. In most practical cases, establishing the topology prior to a deployment is not possible because the exact placement of nodes and the existence of a reliable link between any tw...
Article
Full-text available
The energy consumption of large-scale data centers or server clusters is expected to grow significantly in the next couple of years contributing to up to 13% of the worldwide energy demand in 2030. As the involved processing units require a disproportional amount of energy when they are idle, underutilized, or overloaded, balancing the supply of an...
Conference Paper
Full-text available
The future, in which mobile robots and human beings intermingle in industrial complexes, shopping malls, airports, and similar areas, is not far. The condition, however , requires the realization of several features, including self-localization, self-navigation, identification and avoidance of obstacles , and dynamic route discovery. Indoor localiz...
Conference Paper
Full-text available
Wireless electrocardiograms (WECGs) allow longterm monitoring of patients in their residential and work environments. However, the measurements are easily affected by motion artifacts. To reason about and remove the artifacts, reference models (signals) are needed. One way to construct these models is by employing motion sensors that pick up the mo...
Conference Paper
Full-text available
The electrocardiogram (ECG) is a reliable tool for monitoring cardiac conditions non-invasively. Its use is nowadays widespread and extends beyond purely medical purposes. Nevertheless, its application in residential settings comes with drawbacks. Non-stationary noise caused by motion reduces the signal’s quality and alters the signal’s characteris...
Conference Paper
Full-text available
In the past two decades, several applications have been proposed for Wireless Sensor Networks (WSNs). Some of these applications, such as habitat monitoring, active volcano monitoring, and toxic gas detection, exclude the involvement of human presence because the environments are either dangerous, inaccessible, or too extensive. The scope of these...
Article
Full-text available
Wireless sensor networks accommodating the mobility of nodes will play important roles in future. In residential, rehabilitation, and clinical settings, sensor nodes can be attached to the body of patients for long-term and uninterrupted monitoring of vital biomedical signals. Likewise, in industrial settings, workers as well as mobile robots can c...
Article
Full-text available
A wireless sensor network (WSN) assisted by Unmanned Aerial Vehicles (UAVs) can be used to monitor various phenomena in remote, extensive, inaccessible, or dangerous places. The WSN on the ground can provide close-to-the-scene sensing, in-network data processing, and multi-hop communication. The UAVs can interface the ground network with a remote c...
Article
Full-text available
In multi-hop wireless networks, such as wireless sensor networks, some nodes are more important than others due to their physical and topological significance, their degree of connectivity, communication load, or simply physical placement. Expressing their significance in a measurable way can be useful for communication protocols to assign particul...
Conference Paper
Full-text available
The joint use of Unmanned Aerial Vehicles (UAVs) and wireless sensor networks (WSN) enables to monitor dangerous and inaccessible places. However, the success of this deployment depends on the quality of the wireless links connecting the sensor nodes on the ground with one another and with the UAVs. These links are affected by several factors inclu...
Chapter
Full-text available
The energy consumption of large-scale data centers or server clusters is expected to grow significantly in the next couple of years contributing to up to 13% of the worldwide energy demand in 2030. As the involved processing units require a disproportional amount of energy when they are idle, underutilized or overloaded, balancing the supply of and...
Conference Paper
Full-text available
Wireless electrocardiograms (WECG) facilitate the long-term monitoring of patients in their residential environment. However, the freedom of movement provokes motion artifacts in the measurements of the useful signals, which significantly affect the quality of the data. In this paper, we propose a tensor decomposition method to combine data from he...
Conference Paper
Full-text available
A certain class of wireless devices such as elec-trocardiogram (ECG), electromyogram (EMG) and electroen-cephalogram (EEG), are very useful for telemedicine because they enable the free movement of patients while vital biophysical measurements are taken from them. However, these devices are very sensitive to motion artifacts-electric potentials gen...
Article
Full-text available
Organising nodes into efficient clusters in wireless sensor networks facilitates data aggregation and command dissemination. But clustering is a complex and costly process, since it has to be carried out in a distributed and periodic manner. In this paper we propose a simple clustering strategy employing an adjacency matrix which encodes nodes' nei...
Presentation
Full-text available
In this presentation the usefulness of tensor decomposition as a tool for unsupervised learning is illustrated. The analysis of resource utilisation in large-scale data centre is taken as an application.
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Data
A 24-hour resource utilisation traces from the Enterprise Cloud Infrastructure(ECI) @ TU Dresden. At the time we took measurement, the ECI was interconnecting 59 compute servers and 29 storage servers organised into 9 clusters and hosting 1190 commercial virtual machines. This data sets consists of 14 key performance indicators (CPU utilisation in...
Conference Paper
Full-text available
The introduction of virtualization and cloud computing has enabled a large number of containers/virtual machines to share computing resources. Nevertheless, the number and size of data centres are still on the rise, partly on account of an ever increasing amount of generated data and workloads worldwide. On the other hand, independent studies indic...
Article
Full-text available
The reliability of a wireless sensor network is often associated with its capacity to maintain an end-to-end connection in the presence of unreliable links or node failure []. It is also associated with the level of partitioning the network suffers when some nodes fail or exhaust their batteries. Despite being a critical feature, often it is not cl...
Article
Full-text available
Based on an application in the field of server consolidation, we consider the one-dimensional cutting stock problem with nondeterministic item lengths. After a short introduction to the general topic we investigate the case of normally distributed item lengths in more detail. Within this framework, we present two lower bounds as well as two heurist...
Conference Paper
Full-text available
Wireless electrocardiograms facilitate long-term and affordable monitoring of patients in their residential and work environments. However, the measurements are often affected by motion artifacts whose statistical properties are difficult to model or estimate. In this paper we employ tensor decomposition to model motion artifacts. Our approach is b...
Conference Paper
Full-text available
The worldwide workload of the public cloud infrastructure has been increasing steadily for the past many years and the latest statistics indicate that it will remain so for the coming years. At the same time, the energy consumption of the cloud infrastructure is considerably high. In this respect, the efficient utilisation of computing resources is...
Conference Paper
Full-text available
The use of wireless electrocardiograms, wearable as well as implants, enable long-term and unobtrusive monitoring of patients in their everyday living and working environments. If enriched by environmental contexts, these devices can be vital for early detection of cardiovascular diseases. Often cardiologists encourage patients to keep medical jour...
Conference Paper
Full-text available
Cardiovascular diseases (CVD) claim tens of millions of lives worldwide every year. About one-third of these die before they reach 70. For decades, a considerable effort has been made to supplement clinical treatments with telemedicine. In this respect, wireless electrocardiograms play a vital role, since affordable, unobtrusive, and long-term moni...
Conference Paper
Full-text available
The energy consumption of large-scale data centers or server clusters is expected to grow significantly in the next couple of years contributing to up to 13 percent of the worlwide energy demand in 2030. As the involved processing units require a disproportional amount of energy when they are idle, underutilized or overloaded, balancing the supply...
Chapter
Full-text available
The sensing and design principles we considered so far can have another and crucial application, which is the harvesting of energy from the environment to power the sensors themselves. You may recall that in Chapter 1 I defined sensors as devices that transform one form of energy to another (often to electrical energy). You can see that I have alre...
Chapter
Full-text available
Designing a good sensor is the first step towards interfacing the physical world with the virtual world. Two additional steps are required before the data obtained from a sensor can be useful. The first step deals with determining whether the data represent the physical reality and the second step deals with understanding the meaning of the sensed...
Conference Paper
Full-text available
One of the strategies employed to deal with resource inefficiency in data centres is dynamic virtual machine/container consolidation. The idea behind is, by populating physical servers with an optimal number of virtual machines, all the server's resources (CPU, memory, network bandwidth, etc.) can be utilised effectively. This approach requires (1)...
Conference Paper
Full-text available
Wireless electrocardiograms can be useful for a wide range of applications including early detection of seizures onset, West Syndrome, sleep apnoea, Temporal Lobe Epilepsy (TLE), supra-ventricular tachycardia, atrial flutter, and atrial fibrillation. One of the advantages of using wireless sensing platforms in telemedicine is that patients can free...
Conference Paper
Full-text available
Wireless sensor networks are useful for a large number of healthcare applications which require mobile nodes. Most existing applications rely on body area networks (BAN) which require the presence of additional devices, such as mobile phones, to transfer data from the BAN to a remote base station or a server. In this paper we propose to extend BAN...
Conference Paper
Full-text available
Wireless sensor networks supporting the free mobility of nodes can be useful for several applications. For example, in residential areas and rehab centres, sensors can be attached to subjects to monitor their movements, body exertions, and cardiac activities. These benefits, however, are also challenged by the difficulty of establishing reliable an...
Article
Full-text available
Data centres and similar sever clusters consume a large amount of energy. However, not all consumed energy produces a useful work. Servers consume a disproportional amount of energy when they are idle, underutilised, or overloaded. The effect of these conditions can be minimised by attempting to balance the demand for and the supply of resources th...
Preprint
Full-text available
Data centres and similar server clusters consume a large amount of energy. However, not all consumed energy produces useful work. Servers consume a disproportional amount of energy when they are idle, underutilised, or overloaded. The effect of these conditions can be minimised by attempting to balance the demand for and the supply of resources thr...
Book
This book constitutes the proceedings of the First International Conference on Information and Communication Technology for Development for Africa, ICT4DA 2017, held in Bahir Dar, Ethiopia, in September 2017. The 31 revised full papers presented were carefully reviewed and selected from 72 submissions. The papers address the impact of ICT in foster...
Conference Paper
Wireless sensor networks that support the mobility of nodes are finding applications in different areas such as healthcare, elderly care, and rehabilitation from total knee and hip replacement. However, these application areas also require reliable and high throughput networks. Considering the high fluctuation of link quality during mobility, proto...
Conference Paper
Recently, bulk-data or burst transmission has been the focus of research in wireless sensor networks. The aim is to benefit applications which require high throughput but small scale deployment. Healthcare applications and applications which are intended to support independent living for the elderly are typical examples. The main idea is to exclusi...
Conference Paper
Full-text available
The ever increasing demand for Internet traffic, storage and processing requires an ever increasing amount of hardware resources. In addition to this, infrastructure providers over-provision system architectures to serve users at peak times without performance delays. Over-provisioning leads to underuti-lization and thus to unnecessary power consum...
Conference Paper
Full-text available
Emerging mobile platforms integrate heterogeneous, multi-core processors to eciently deal with the heterogeneity of data (in magnitude , type, and quality). The main goal is to achieve a high degree of energy-proportionality which correspond with the nature and uctua-tion of mobile workloads. Most existing power and energy consumption analyses of t...
Book
Full-text available
Very few twenty‐century scientists made as a lasting influence on modern society as Albert Einstein and Sigmund Freud. Physicists routinely use the theories Einstein developed a century ago to analyse and comprehend cosmological and quantum phenomena. Similarly, some of the vital models contemporary psychologists routinely apply in order to explain...
Chapter
Full-text available
The amount of data that are computed, stored, and communicated by data centres has been increasing for years and will keep on increasing. One of the consequences of this phenomenon is the deployment of a considerable number of high-capacity servers each year. In contrast, several independent studies reveal that resources (including energy) are not...
Data
Synchronously measured data from a wireless ECG (using the Shimmer Platform) and 3d accelerometer sensor. The accelerometer was deployed on the ECG platform and approximated the movement of the five leads measuring the ECG signal.
Conference Paper
One of the fundamental tasks of a smart-grid is achieving an optimal balance between the supplied and consumed energy in the grid. The optimal balance avoids underutilisation as well as overloading of energy sources; minimises the cost of energy transportation and storage; and reduces the price of energy. In this paper we propose a stochastic model...
Conference Paper
Full-text available
This paper addresses link quality fluctuation and its impact on the packet delivery capacity of wireless sensor networks. Independent studies have previously confirmed that link quality fluctuates even in a static deployment and understanding stable durations, go o d and bad alike, can contribute to the efficient transmission of packets. We propose...
Conference Paper
Full-text available
Dynamic server consolidation in data centres enables the efficient usage of resources, because it aims to minimise the underutilisation or overloading of physical servers, both of which produce a dispropor-tional amount of energy consumption. Server consolidation takes place by migrating virtual machines from one server to another while the virtual...
Conference Paper
Full-text available
The amount of data that are computed, stored, and shared over the Internet is rising at an unprecedented scale. This has necessitated more servers to be deployed and drastic improvement in the capacity of individual servers. However, several independent studies also reveal that resources are not optimally utilised in most existing data centres and...
Article
Full-text available
Several applications have been proposed for mobile wireless sensor networks. Some of these applications require the transfer of a large amount of data in a short period of time. This is challenging, since mobility can lead to a deterioration in the quality of an established link. Frequent link disconnection may in turn require a mobile node to repe...
Conference Paper
Full-text available
Understanding fluctuations of link quality in a wireless sensor network is useful for different reasons. For example, nodes can determine when and for how long they should transmit packets, so that they can reduce packet loss rate and the cost of retransmission (delay as well as power consumption). However, because the quality of a link depends on...