Flexible Evaluation of RFID System Parameters using Rapid Prototyping

Abstract-Today's RFID systems are dependent on a wide range of different parameters, that influence the overall performance. Such system parameters can for example be the selected data rate, encoding scheme, modulation setting, transmit power or different hardware configurations, like one or two antenna scenarios. Furthermore, it is often desired to optimise several performance goals, like read-out range, read-out quality, throughput, etc., which are often contradicting each other. In order to achieve a desired performance of an RFID system, it is essential to understand the influences of the individual parameters of interest and their interconnection. Due to the multitude, wide range and interdependencies of influencing factors, this however is a complex task. Simulations offer insights in these relations but rely on the correct modeling of the dependencies of-and between the parameters. With our established prototyping system for RFID, we are able to flexibly and accurately explore the influence and interconnection of such parameters in a wide range on a basis of real-time measurements. Results on the evaluation of read-out quality depending on the transmit power and the data rate are presented

Feasibility, psychological outcomes and practical use of a stress-preventive leadership intervention in the workplace hospital:The results of a mixed-method phase-II study

OBJECTIVES: Hospitals are psychologically demanding workplaces with a need for context-specific stress-preventive leadership interventions. A stress-preventive interprofessional leadership intervention for middle management has been developed. This phase-II study investigates its feasibility and outcomes, including work-related stress, well-being and transformational leadership. DESIGN: This is a mixed-methods study with three measure points (T0: baseline, T1: after the last training session, T2: 3-month follow-up). Additionally, focus groups were conducted to assess participants’ change in everyday work. SETTING: A tertiary hospital in Germany. PARTICIPANTS: N=93 leaders of different professions. INTERVENTION: An interactive group setting intervention divided in five separate sessions ((1) self-care as a leader, (2) leadership attitudes and behaviour, (3) motives, needs and stressors of employees, (4) strengthen the resource ‘team’, (5) reflection and focus groups). The intervention was conducted between June 2018 and March 2020 in k=5 runs of the intervention. OUTCOME MEASURES: Feasibility and acceptance were measured with a self-developed intervention specific questionnaire. Psychological outcomes were assessed with the following scales: work-related strain with the Irritation Scale, well-being with the WHO-5 Well-being Index and transformational leadership with the Questionnaire of Integrative Leadership. RESULTS: After the intervention at T2, over 90% of participants reported that they would recommend the intervention to another coworker (92.1%, n=59) and all participants (n=64) were satisfied with the intervention and rated the intervention as practical relevant for their everyday work. Participants’ self-rated cognitive irritation was reduced, whereas their well-being and transformational leadership behaviour were improved over time. Focus group discussions revealed that participants implemented intervention contents successfully in their everyday work. CONCLUSIONS: This intervention was feasible and showed first promising intraindividual changes in psychological outcomes. Participants confirmed its practical relevance. As a next step, the intervention will be evaluated as part of a multicentre—randomised controlled trial within the project SEEGEN (SEElische GEsundheit am Arbeitsplatz KrankeNhaus)

Renewable Energy in the Context of Sustainable Development

Historically, economic development has been strongly correlated with increasing energy use and growth of greenhouse gas (GHG) emissions. Renewable energy (RE) can help decouple that correlation, contributing to sustainable development (SD). In addition, RE offers the opportunity to improve access to modern energy services for the poorest members of society, which is crucial for the achievement of any single of the eight Millennium Development Goals. Theoretical concepts of SD can provide useful frameworks to assess the interactions between SD and RE. SD addresses concerns about relationships between human society and nature. Traditionally, SD has been framed in the three-pillar model—Economy, Ecology, and Society—allowing a schematic categorization of development goals, with the three pillars being interdependent and mutually reinforcing. Within another conceptual framework, SD can be oriented along a continuum between the two paradigms of weak sustainability and strong sustainability. The two paradigms differ in assumptions about the substitutability of natural and human-made capital. RE can contribute to the development goals of the three-pillar model and can be assessed in terms of both weak and strong SD, since RE utilization is defined as sustaining natural capital as long as its resource use does not reduce the potential for future harvest. The relationship between RE and SD can be viewed as a hierarchy of goals and constraints that involve both global and regional or local considerations. Though the exact contribution of RE to SD has to be evaluated in a country specifi c context, RE offers the opportunity to contribute to a number of important SD goals: (1) social and economic development; (2) energy access; (3) energy security; (4) climate change mitigation and the reduction of environmental and health impacts. The mitigation of dangerous anthropogenic climate change is seen as one strong driving force behind the increased use of RE worldwide. The chapter provides an overview of the scientific literature on the relationship between these four SD goals and RE and, at times, fossil and nuclear energy technologies. The assessments are based on different methodological tools, including bottom-up indicators derived from attributional lifecycle assessments (LCA) or energy statistics, dynamic integrated modelling approaches, and qualitative analyses. Countries at different levels of development have different incentives and socioeconomic SD goals to advance RE. The creation of employment opportunities and actively promoting structural change in the economy are seen, especially in industrialized countries, as goals that support the promotion of RE. However, the associated costs are a major factor determining the desirability of RE to meet increasing energy demand and concerns have been voiced that increased energy prices might endanger industrializing countries’ development prospects; this underlines the need for a concomitant discussion about the details of an international burden-sharing regime. Still, decentralized grids based on RE have expanded and already improved energy access in developing countries. Under favorable conditions, cost savings in comparison to non-RE use exist, in particular in remote areas and in poor rural areas lacking centralized energy access. In addition, non-electrical RE technologies offer opportunities for modernization of energy services, for example, using solar energy for water heating and crop drying, biofuels for transportation, biogas and modern biomass for heating, cooling, cooking and lighting, and wind for water pumping. RE deployment can contribute to energy security by diversifying energy sources and diminishing dependence on a limited number of suppliers, therefore reducing the economy’s vulnerability to price volatility. Many developing countries specifically link energy access and security issues to include stability and reliability of local supply in their definition of energy security. Supporting the SD goal to mitigate environmental impacts from energy systems, RE technologies can provide important benefits compared to fossil fuels, in particular regarding GHG emissions. Maximizing these benefits often depends on the specific technology, management, and site characteristics associated with each RE project, especially with respect to land use change (LUC) impacts. Lifecycle assessments for electricity generation indicate that GHG emissions from RE technologies are, in general, considerably lower than those associated with fossil fuel options, and in a range of conditions, less than fossil fuels employing carbon capture and storage (CCS). The maximum estimate for concentrating solar power (CSP), geothermal, hydropower, ocean and wind energy is less than or equal to 100 g CO2eq/kWh, and median values for all RE range from 4 to 46 g CO2eq/kWh. The GHG balances of bioenergy production, however, have considerable uncertainties, mostly related to land management and LUC. Excluding LUC, most bioenergy systems reduce GHG emissions compared to fossil-fueled systems and can lead to avoided GHG emissions from residues and wastes in landfill disposals and co-products; the combination of bioenergy with CCS may provide for further reductions. For transport fuels, some first-generation biofuels result in relatively modest GHG mitigation potential, while most next-generation biofuels could provide greater climate benefits. To optimize benefits from bioenergy production, it is critical to reduce uncertainties and to consider ways to mitigate the risk of bioenergy-induced LUC. RE technologies can also offer benefits with respect to air pollution and health. Non-combustion-based RE power generation technologies have the potential to significantly reduce local and regional air pollution and lower associated health impacts compared to fossil-based power generation. Impacts on water and biodiversity, however, depend on local conditions. In areas where water scarcity is already a concern, non-thermal RE technologies or thermal RE technologies using dry cooling can provide energy services without additional stress on water resources. Conventional water-cooled thermal power plants may be especially vulnerable to conditions of water scarcity and climate change. Hydropower and some bioenergy systems are dependent on water availability, and can either increase competition or mitigate water scarcity. RE specific impacts on biodiversity may be positive or negative; the degree of these impacts will be determined by site-specific conditions. Accident risks of RE technologies are not negligible, but the technologies’ often decentralized structure strongly limits the potential for disastrous consequences in terms of fatalities. However, dams associated with some hydropower projects may create a specific risk depending on site-specific factors. The scenario literature that describes global mitigation pathways for RE deployment can provide some insights into associated SD implications. Putting an upper limit on future GHG emissions results in welfare losses (usually measured as gross domestic product or consumption foregone), disregarding the costs of climate change impacts. These welfare losses are based on assumptions about the availability and costs of mitigation technologies and increase when the availability of technological alternatives for constraining GHGs, for example, RE technologies, is limited. Scenario analyses show that developing countries are likely to see most of the expansion of RE production. Increasing energy access is not necessarily beneficial for all aspects of SD, as a shift to modern energy away from, for example, traditional biomass could simply be a shift to fossil fuels. In general, available scenario analyses highlight the role of policies and finance for increased energy access, even though forced shifts to RE that would provide access to modern energy services could negatively affect household budgets. To the extent that RE deployment in mitigation scenarios contributes to diversifying the energy portfolio, it has the potential to enhance energy security by making the energy system less susceptible to (sudden) energy supply disruption. In scenarios, this role of RE will vary with the energy form. With appropriate carbon mitigation policies in place, electricity generation can be relatively easily decarbonized through RE sources that have the potential to replace concentrated and increasingly scarce fossil fuels in the building and industry sectors. By contrast, the demand for liquid fuels in the transport sector remains inelastic if no technological breakthrough can be achieved. Therefore oil and related energy security concerns are likely to continue to play a role in the future global energy system; as compared to today these will be seen more prominently in developing countries. In order to take account of environmental and health impacts from energy systems, several models have included explicit representation of these, such as sulphate pollution. Some scenario results show that climate policy can help drive improvements in local air pollution (i.e., particulate matter), but air pollution reduction policies alone do not necessarily drive reductions in GHG emissions. Another implication of some potential energy trajectories is the possible diversion of land to support biofuel production. Scenario results have pointed at the possibility that climate policy could drive widespread deforestation if not accompanied by other policy measures, with land use being shifted to bioenergy crops with possibly adverse SD implications, including GHG emissions. 712 Renewable Energy in the Context of Sustainable Development Chapter 9 The integration of RE policies and measures in SD strategies at various levels can help overcome existing barriers and create opportunities for RE deployment in line with meeting SD goals. In the context of SD, barriers continue to impede RE deployment. Besides market-related and economic barriers, those barriers intrinsically linked to societal and personal values and norms will fundamentally affect the perception and acceptance of RE technologies and related deployment impacts by individuals, groups and societies. Dedicated communication efforts are therefore a crucial component of any transformation strategy and local SD initiatives can play an important role in this context. At international and national levels, strategies should include: the removal of mechanisms that are perceived to work against SD; mechanisms for SD that internalize environmental and social externalities; and RE strategies that support low-carbon, green and sustainable development including leapfrogging. The assessment has shown that RE can contribute to SD to varying degrees; more interdisciplinary research is needed to close existing knowledge gaps. While benefi ts with respect to reduced environmental and health impacts may appear more clear-cut, the exact contribution to, for example, social and economic development is more ambiguous. In order to improve the knowledge regarding the interrelations between SD and RE and to fi nd answers to the question of an effective, economically effi cient and socially acceptable transformation of the energy system, a much closer integration of insights from social, natural and economic sciences (e.g., through risk analysis approaches), refl ecting the different (especially intertemporal, spatial and intra-generational) dimensions of sustainability, is required. So far, the knowledge base is often limited to very narrow views from specifi c branches of research, which do not fully account for the complexity of the issue

Design and exploration of Radio Frequency Identification systems by Rapid Prototyping

Zsfassung in dt. SpracheDie vorliegende Dissertation befasst sich mit dem Aufbau und Design einer flexiblen Rapid Prototyping Umgebung für RFID Systeme. Diese Testumgebung erlaubt die experimentelle Evaluierung von RFID Systemen sowie deren Erforschung in Echtzeit in verschiedenen Versuchsanordnungen. Zusätzlich wird diese Testumgebung benutzt, um neuartige Signalverarbeitungsalgorithmen für RFID Lesegeräte zu testen, welche eine Verbesserung der Leistungsfähigkeit von Empfängern versprechen. Drei verschiedene Szenarien werden in dieser Dissertation betrachtet:1. Das erste Szenario betrachtet die Kommunikation eines einzelnen RFID Tags mit dem Lesegerät. Die Effienz des optimalen Maximum-Likelihood Empfängers wird gezeigt und Verluste durch Kanalschätzung und Synchronisation werden diskutiert.Wegen der großen Abweichung von der nominalen Datenrate in der Tag-Reader Kommunikation zeigt sich, dass Synchronisation den kritischsten Aspekt im Empfängerdesign darstellt.2. Im zweiten Szenario kommuniziert das RFID Tag mit einem Lesegerät mit mehreren Empfangsantennen. Das Verwenden mehrerer Empfangsantennen ermöglicht zwei Vorteile: Erstens zeigt die Dissertation, dass eine Richtungslokalisierung mit nur zwei Empfangsantennen am Lesegerät möglich ist, sofern der Übertragungskanal geringem Schwund ausgesetzt ist. Zweitens können mehrere Empfangsantennen in einer Umgebung, die stark von Mehrwegeausbreitung geprägt ist, für Diversitätsempfang benutzt werden. Dieses Szenario adressiert das wichtige Thema der Zuverlässigkeit von RFID Systemen in Schwundkanälen.3. In einem dritten Szenario wird die gleichzeitige Kommunikation eines Lesegeräts mit mehreren RFID Tags untersucht. Solche Signalkollisionen werden modelliert, und verschieden Empfängerstrukturen werden entwickelt, um die einzelnen Signalkomponenten der Kollision separieren zu können. Dieses Thema adressiert den Datendurchsatz in RFID Systemen.Es wird gezeigt, dass ein Lesegerät, welches Kollisionen von zwei Tags auflösen kann, eine Datendurchsatzerhöhung um den Faktor 1,6 erreicht.Die Leistungsfähigkeit der einzelnen Empfänger wird gezeigt.Für alle drei Szenarios wurden Modelle von Signalkonstellationen im Basisband des Lesegeräts entwickelt, welche auch durch Messdaten unterstützt werden. Implementierungsaspekte werden diskutiert, und die Leistungsfähigkeit wird in Simulation und Messung verglichen.In this thesis I describe the setup and design of a flexible rapid prototyping platform for RFID systems to provide an experimental veri fication environment for RFID systems, that allows their real-time exploration in distinct measurement setups. Furthermore, I use this system to test the feasibility of novel signal processing algorithms for RFID reader receivers, which promise a performance increase to state-of-the-art-receivers. Three different scenarios are considered:1. In the first scenario, a single tag communicates with a single receive antenna reader. The performance of the optimal maximum likelihood sequence decoder is identifi ed, and losses due to channel estimation and synchronisation are discussed. Due to the wide deviation from the nominal data rate in the uplink communication, especially synchronisation shows to be a critical issue.2. In the second scenario, the single tag communicates with a multiple receive antenna RFID reader. This multiple receive antenna system allows for mainly two advances: in a strong line of sight environment I demonstrate that a direction of arrival estimation of the tag signal is feasible, while for an environment with strong multipath components, I propose a maximum ratio combining for diversity combining at the reader receiver. Hence, in the line of sight case I address localisation of RFID tags, while the diversity combining addresses the topic of reliability of the communication in a high fading environment.3. Finally, in the third scenario multiple tags communicate with the reader simultaneously and generate a collision. Such collisions are modeled on the physical layer, and different receivers using either a single or multiple receive antennas are proposed to recover from a collision at the physical layer. Hence, the topic of throughput in multiple tag communications is addressed here, which is shown to increase by a factor of 1.6 compared to the throughput of a conventional system, in the case a reader can recover from collisions of up to two tags. Moreover, performance tradeoffs regarding throughput, reliability and receiver complexity are shown.For all three scenarios, models for the signal constellations at the reader receiver are developed and supported by measurement data.Implementation aspects of the receivers are discussed, and performance comparisons not only by means of simulations but also by measurements are presented.14