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This work presents the analysis of data recorded by an eye tracking device in the course of evaluating a foveated rendering approach for head-mounted displays (HMDs). Foveated rendering methods adapt the image synthesis process to the user’s gaze and exploiting the human visual system’s limitations to increase rendering performance. Especially, foveated rendering has great potential when certain requirements have to be fulfilled, like low-latency rendering to cope with high display refresh rates. This is crucial for virtual reality (VR), as a high level of immersion, which can only be achieved with high rendering performance and also helps to reduce nausea, is an important factor in this field. We put things in context by first providing basic information about our rendering system, followed by a description of the user study and the collected data. This data stems from fixation tasks that subjects had to perform while being shown fly-through sequences of virtual scenes on an HMD. These fixation tasks consisted of a combination of various scenes and fixation modes. Besides static fixation targets, moving tar- gets on randomized paths as well as a free focus mode were tested. Using this data, we estimate the precision of the utilized eye tracker and analyze the participants’ accuracy in focusing the displayed fixation targets. Here, we also take a look at eccentricity-dependent quality ratings. Comparing this information with the users’ quality ratings given for the displayed sequences then reveals an interesting connection between fixation modes, fixation accuracy and quality ratings.
Studienverläufe von Studenten weichen nicht selten vom offiziell geplanten Curriculum ab. Für eine den Studienerfolg verbessernde Planung und Weiterentwicklung von Studiengängen und Curricula fehlen den Verantwortlichen häufig Erkenntnisse über tatsächliche sowie typischerweise erfolgreiche und weniger erfolgreiche Studienverlaufsmuster. Process-Mining-Techniken können helfen, mehr Transparenz bei der Auswertung von Studienverläufen zu schaffen und so die Erkennung typischer Studienverlaufsmuster, die Überprüfung der Übereinstimmung der konkreten Studienverläufe mit dem vorgegebenen Curriculum sowie eine zielgerechte Verbesserung des Curriculums zu unterstützen.
Real-World Performance of current Mesh Protocols in a small-scale Dual-Radio Multi-Link Environment
(2017)
Two key questions motivated the work in this paper: What is the impact of different usage schemes for multiple channels in a dual-radio Wireless Mesh Network (WMN), and what is the impact of some popular WMN routing protocols on its performance. These two questions were evaluated in a small and simple real-world scenario. A major concern was reproducibility of the results. We show that it is beneficial to use both radios on different frequencies in a fully meshed environment with four routers. The routing protocols Babel, B.A.T.M.A.N. V, BMX7 and OLSRv2 recognize a saturated channel and prefer the other one. We show that in our scenario all of the protocols perform equally well since the protocol overhead is comparably low not influencing the overall performance of the network.
Comparación de perfiles de ansiedad matemática entre estudiantes mexicanos y estudiantes alemanes
(2017)
Se determinan los perfiles de ansiedad matemática de estudiantes mexicanos y estudiantes alemanes por medio de la aplicación de un cuestionario desarrollado ex profeso. La ansiedad matemática se define en términos de tres descriptores: creencias, actitudes y emociones. Los autores definen un Índice de Ansiedad Matemática, al aplicarlo encuentran que los estudiantes alemanes presentan un valor mayor de dicho Índice, lo que significa que tienen una mayor nivel de ansiedad matemática. Las diferencias en los valores del Índice de Ansiedad Matemática se interpretan en términos de diferencias culturales. La interpretación parece ser consistente con las diferencias culturales y se ajusta a los resultados obtenidos.
Political economic analyses of recent social protection reforms in Asian, African or Latin American countries have increased throughout the last few years. Yet, most contributions focus on one social protection mechanism only and do not provide a comparative approach across policy areas. In addition, most studies are empirical studies, with no or very limited theoretical linkages. The paper aims to explain multiple trajectories of social protection reform processes looking at cash transfers and social health protection policies in Kenya. It develops a taxonomy and suggest a conceptual framework to assess and explain reform dynamics across different social protection pillars. In order to allow for a more differentiated typology and enable us to understand different reform dynamics, the article uses the approach on gradual institutional change. While existing approaches to institutional change mostly focus on institutional change prompted by exogenous shocks or environmental shifts, this approach takes account of both, exogenous and endogenous sources of change.
In recent years, there has been a growing interest in the start-up scene in sub-Saharan Africa. "Silicon Savannah" is today widely used to describe the thriving IT industry in and around Nairobi. Kenya's geographical advantage, its favorable economic reforms, and mature start-up ecosystem makes it stands out positively. Since a lot of hype exists around the start-up scene many investors are drawn to it, but in reality very few start-ups are investment-ready. The increasing start-up requirements and needs force incubators to diversify their offer. In contrast, to traditional incubators, an Innovation Hub (Hub) is characterized based on the concept of open innovation and collaboration. A Hub nurtures an enabling environment where a community of entrepreneurs can grow. At the same time, it serves as a nexus point for the local start-up community, investors, academia, technology companies and the wider private sector. It aims to create a structure where people serendipitously interact with others that they would not typically meet. Considering the great interest for and the large amounts of money invested in Hubs by governments, universities, private companies and other interested parties, not only researchers have been raising the question of the actual benefit of Hubs. This research study aims to investigate to what extent the support offered by the Hubs is tackling the challenges faced by start-ups in Nairobi, Kenya. The analysis can serve as a basis for identifying strength and weaknesses in the Hub models.
Impact of atmospheric aerosols on photovoltaic energy production - Scenario for the Sahel zone
(2017)
Photovoltaic (PV) energy is one option to serve the rising global energy need with low environmental impact. PV is of particular interest for local energy solutions in developing countries prone to high solar insolation. In order to assess the PV potential of prospective sites, combining knowledge of the atmospheric state modulating solar radiation and the PV performance is necessary. The present study discusses the PV power as function of atmospheric aerosols in the Sahel zone for clear-sky-days. Daily yields for a polycrystalline silicon PV module are reduced by up to 48 % depending on the climatologically-relevant aerosol abundances.
Service robots performing complex tasks involving people in houses or public environments are becoming more and more common, and there is a huge interest from both the research and the industrial point of view. The RoCKIn@Home challenge has been designed to compare and evaluate different approaches and solutions to tasks related to the development of domestic and service robots. RoCKIn@Home competitions have been designed and executed according to the benchmarking methodology developed during the project and received very positive feedbacks from the participating teams. Tasks and functionality benchmarks are explained in detail.
RoCKIn@Work was focused on benchmarks in the domain of industrial robots. Both task and functionality benchmarks were derived from real world applications. All of them were part of a bigger user story painting the picture of a scaled down real world factory scenario. Elements used to build the testbed were chosen from common materials in modern manufacturing environments. Networked devices, machines controllable through a central software component, were also part of the testbed and introduced a dynamic component to the task benchmarks. Strict guidelines on data logging were imposed on participating teams to ensure gathered data could be automatically evaluated. This also had the positive effect that teams were made aware of the importance of data logging, not only during a competition but also during research as useful utility in their own laboratory. Tasks and functionality benchmarks are explained in detail, starting with their use case in industry, further detailing their execution and providing information on scoring and ranking mechanisms for the specific benchmark.
Universities, Entrepreneurship and Enterprise Development in Africa – Conference Proceedings 2016
(2017)
These proceedings are the outcome of the 5th annual joint conference on “Universities Entrepreneurship and Enterprise Development in Africa” between the University of Nairobi, Kenya, the University of Cape Coast, Ghana, and Bonn-Rhein-Sieg University of Applied Sciences, Germany, held on 10-11 November 2016 on Campus Sankt Augustin, Bonn-Rhein-Sieg University of Applied Sciences.
Dare – Democracy and Science
(2017)
Das Cutting sticks-Problem ist in seiner allgemeinen Formulierung ein NP-vollständiges Problem mit Anwendungspotenzialen im Bereich der Logistik. Unter der Annahme, dass P ungleich NP (P != NP) ist, existieren keine effizienten, d.h. polynomiellen Algorithmen zur Lösung des allgemeinen Problems.
In diesem Papier werden für eine Reihe von Instanzen effiziente Lösungen angegeben.
Das Cutting sticks-Problem ist in seiner allgemeinen Formulierung ein NP-vollständiges Problem mit Anwendungspotenzialen im Bereich der Logistik. Unter der Annahme, dass P ungleich NP (P != NP) ist, existieren keine effizienten, d.h. polynomiellen Algorithmen zur Lösung des allgemeinen Problems.
In diesem Papier werden Ansätze aufgezeigt, mit denen bestimmte Instanzen des Problems effizient berechnet werden können. Für die Berechnung wichtige Parameter werden charakterisiert und deren Beziehung untereinander analysiert.
These times are very troubled ones. Not only do wars and political unrest seem to prevail in different regions of the world, but, corruption and fraud have reached an incredible dimension, too. It seems that societies have, to a large extent, lost values in which they had formerly believed in. These issues may be the background why at the moment Corporate Social Responsibility (CSR) as a voluntary commitment is discussed in public that intensively. However, one gets the impression that this rather often seems to be superficial. Therefore, it is time to do some in-depth research to identify whether there is real substance behind these discussions or not. Latin America is a big continent with a greater number of countries which are running through difficult times as to corruption and fraud. Consequently, the author studied the policy of the central employers association Consejo Empresarial de America Latina (CEAL) with respect to the role of CSR. On the basis of statements, news and results of studies being regularly published, conclusions were drawn to which extent social and environmental aspects, along the line of ISO 26000, are playing a relevant role.
In order to avoid a too narrow view of the issue, a holistic approach concerning the generalsituation of Latin America has been selected using parameters such as economic growth, increase of population, poverty, inequality, and the global responsibility for environment. Furthermore, apart from the central organization CEAL, regional and national institutions with a specific mission for spreading and implementing CSR and two communal projects were analyzed as well. The conclusion of the paper is that there are some CSR "lighthouses" but an urgent need exists to spread the idea of CSR more intensively across the continent. Corresponding recommendations about how to increase the relevance of CSR in Latin America are given at the end of the paper.
The combination of Software-Defined Networking (SDN) and Wireless Mesh Network (WMN) is challenging due to the different natures of both concepts. SDN describes networks with homogeneous, static and centralized controlled topologies. In contrast, a WMN is characterized by a dynamic and distributed network control, and adds new challenges with respect to time-critical operation. However, SDN and WMN are both associated with decreasing the operational costs for communication networks which is especially beneficial for internet provisioning in rural areas. This work surveys the current status for Software-Defined Wireless Mesh Networking. Besides a general overview in the domain of wireless SDN, this work focuses especially on different identified aspects: representing and controlling wireless interfaces, control-plane connection and topology discovery, modulation and coding, routing and load-balancing and client handling. A complete overview of surveyed solutions, open issues and new research directions is provided with regard to each aspect.
In January 2015, German trade and industry announced to support the national animal welfare initiative "Initiative Tierwohl" (ITW) which stands for a more sustainable and animal-friendly meat production. A web content analysis shows that the ITW initiative has been widely picked up and discussed by online media and that user comments are quite heterogeneous. The current study identifies different types of consumers through factor and cluster analysis and is based on an online survey as well as face-to-face interviews. According to our results, the identified consumer groups demonstrate a rather passive comment behaviour on the internet. In fact, the internet was hardly mentioned as an information source for meat production; consumers more frequently referred to brochures, leaflets and personal contacts with sales personnel.
Argentina substantially contributes to the global organic agriculture and food sector due to its large areas of organically managed agricultural land. However, most of the organic production is foreseen for export. Overall, food supply for the domestic organic market is hardly tapped. This study investigates the current importance of organic agriculture and food production as well as its consumption within the country. The novelty of the study also lies in the observation, documentation and analysis of latest stakeholder-driven developments towards organic agriculture and food. The publication allows to make the Argentinian organic market significantly more visible for the international audience.
Food losses occur for many reasons at all stages of supply chains for fruits, vegetables and potatoes. They cause immense economic, environmental and social costs – not only in developing countries but also in developed countries. According to the European Commission, about 90 million tonnes of food are wasted annually in Europe alone. However, particularly for the early stages of supply chains for fruits, vegetables and potatoes there is still a lack of reliable data. Thus, one objective of this study is to contribute to the quantification of food losses between field and retail, where the main focus is set on potatoes, apples, carrots, strawberries and asparagus. Furthermore, neither reasons why products are removed from the supply chains nor their alternative uses are fully examined yet. This is why, the study takes a look on those issues, too. Results are based on data from an online survey among producers of fruits, vegetables and potatoes in North-Rhine Westphalia, Germany and on interviews with producers and other supply chain experts. Findings suggest that the products’ size and form, their storage capabilities and food safety issues have big impacts on food losses. Despite a small sample size, these findings are in line with recent studies.
Das Thema Nachhaltigkeit hat sich in der heutigen Zeit in vielerlei Hinsicht weiterentwickelt. Auch bei der Entwicklung von Produkten ist der Aspekt der Nachhaltigkeit angekommen und wird vermehrt umgesetzt. Dies hat zur Folge, dass auch der Konsument sich mit der Nachhaltigkeit seines Produkts auseinandersetzt.
Die vorliegende Arbeit behandelt die Fragestellung, ob der Aspekt der Nachhaltigkeit auch bei der Kaufentscheidung eine Rolle spielt. Fokussiert wurden besonders die Aspekte: Nachhaltigkeit und Marketing, Wahrnehmung von nachhaltigen Aspekten der Unternehmen, sowie der Produkte, Vertrauen der Konsumenten in Siegel und die soziale Erwartungshaltung der Konsumenten.
Die Analyse resultiert auf der Basis eines durchgeführten Experiments sowie einer schriftlichen Befragung der 73 Probanden, bestehend aus Studenten der Hochschule Bonn-Rhein-Sieg.
Die Ergebnisse dieser Studie zeigen nicht nur den Handlungsbedarf der Unternehmen, sondern auch die Wahrnehmung der Konsumenten zu Produkten und Unternehmen und dass der Aspekt der Nachhaltigkeit auch bei täglichen Kaufentscheidungen eine Rolle spielen kann.
Viele Bereiche des Wirtschaftslebens werden heute durch die Digitalisierung beeinflusst. Sowohl auf Grundlage neuer technischer Möglichkeiten und der damit einhergehenden Vernetzung, als auch mit einem Wandel im Konsumverhalten hat sich die Sharing Economy entwickelt. Auf dem Gebiet der urbanen Mobilität ergibt sich für Anbieter und Nachfrager eine Vielzahl neuer Möglichkeiten im Rahmen der Sharing Economy. Die Arbeit setzt sich sowohl mit den aktuellen Mobilitätstrends, als auch mit dem Wandel im Konsumverhalten auseinander. Im Fokus steht hierbei das Ridesourcing, also die entgeltlichen Personenbeförderung von privaten Fahrern mit eigenem Fahrzeug, bei der der Fahrgast das Fahrziel bestimmt und die Vorteile die ein Markteintritt dieser Anbieter mit sich bringt.
In Zeiten deutlicher Auswirkungen des Klimawandels und gravierender sozialer Missstände in Teilen der Welt drängen sich dringender denn je für die Weltgemeinschaft die Fragen nach Handlungsoptionen zum Erreichen nachhaltiger Entwicklung auf. Dementsprechend ist auch der öffentliche Sektor gefragt seinen Beitrag zu leisten. Als ein wirkungsvoller Beitrag ist die Etablierung nachhaltiger öffentlicher Beschaffung zu nennen. Um diesen Beitrag adäquat umzusetzen, müssen unter anderem die Richtlinien und Gesetze, die die öffentliche Beschaffung regeln, ausreichend Umsetzungsmöglichkeiten dafür bieten. Mit der jüngsten europäischen Vergaberechtsreform und der daraufhin verabschiedeten deutschen Anpassung der Gesetze ist der Grundstein dafür gelegt worden. Welche erfolgsversprechenden Umsetzungsmöglichkeiten diese rechtliche Basis nun den Kommunen in Deutschland als Hauptakteuren öffentlicher Beschaffung bietet und welche weiteren Erfolgsfaktoren für die Umsetzung nachhaltiger öffentlicher Beschaffung auf kommunaler Ebene entscheidend sind, ist Thema dieses Arbeitspapiers. Ein Praxischeck der Erfolgsfaktoren wird am Beispiel der Stadt Bonn, stellvertretend für die kommunale Ebene in NRW vorgenommen.
Wissen für die Wirtschaft
(2017)
Es gehörte zum Gründungsauftrag der Hochschule Bonn-Rhein-Sieg, Wissenschaft und Wirtschaft zusammenzubringen und gemeinsam Neues zu entwickeln. Die hier vorgestellte Broschüre ist vor allem als Anregung gedacht: Sie zeigt, welche Erfolge aus einer Zusammenarbeit erwachsen und erleichtert es Unternehmen, den ersten Schritt hin zu einer Kooperation mit der H-BRS zu gehen.
Solid-Phase Microextraction (SPME) is a very simple and efficient, solventless sample preparation method, invented by Pawliszyn and coworkers at the University of Waterloo (Canada) in 1989. This method has been widely used in different fields of analytical chemistry since its first applications to environmental and food analysis. SPME integrates sampling, extraction, concentration and sample introduction into a single solvent-free step. The method saves preparation time, disposal costs and can improve detection limits. It has been routinely used in combination with gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) and successfully applied to a wide variety of ompounds, especially for the extraction of volatile and semi-volatile organic compounds from environmental, biological and food samples.
Since the last twenty years, SPME in headspace (HS) mode is used as a valuable sample preparation technique for identifying degradation products in polymers and for determination of rest monomers and other light-boiling substances in polymeric materials. For more than ten years, our laboratory has been involved in projects focused on the application of HS-SPME-GC/MS for the characterization of polymeric materials from many branches of manufacturing and building industries. This book chapter describes the application examples of this technique for identifying volatile organic compounds (VOCs), additives and degradation products in industrial plastics, rubber, and packaging materials.
Emotional communication is a key element of habilitation care of persons with dementia. It is, therefore, highly preferable for assistive robots that are used to supplement human care provided to persons with dementia, to possess the ability to recognize and respond to emotions expressed by those who are being cared-for. Facial expressions are one of the key modalities through which emotions are conveyed. This work focuses on computer vision-based recognition of facial expressions of emotions conveyed by the elderly.
Although there has been much work on automatic facial expression recognition, the algorithms have been experimentally validated primarily on young faces. The facial expressions on older faces has been totally excluded. This is due to the fact that the facial expression databases that were available and that have been used in facial expression recognition research so far do not contain images of facial expressions of people above the age of 65 years. To overcome this problem, we adopt a recently published database, namely, the FACES database, which was developed to address exactly the same problem in the area of human behavioural research. The FACES database contains 2052 images of six different facial expressions, with almost identical and systematic representation of the young, middle-aged and older age-groups.
In this work, we evaluate and compare the performance of two of the existing imagebased approaches for facial expression recognition, over a broad spectrum of age ranging from 19 to 80 years. The evaluated systems use Gabor filters and uniform local binary patterns (LBP) for feature extraction, and AdaBoost.MH with multi-threshold stump learner for expression classification. We have experimentally validated the hypotheses that facial expression recognition systems trained only on young faces perform poorly on middle-aged and older faces, and that such systems confuse ageing-related facial features on neutral faces with other expressions of emotions. We also identified that, among the three age-groups, the middle-aged group provides the best generalization performance across the entire age spectrum. The performance of the systems was also compared to the performance of humans in recognizing facial expressions of emotions. Some similarities were observed, such as, difficulty in recognizing the expressions on older faces, and difficulty in recognizing the expression of sadness.
The findings of our work establish the need for developing approaches for facial expression recognition that are robust to the effects of ageing on the face. The scientific results of our work can be used as a basis to guide future research in this direction.