Spatial Identification Methods and Systems for RFID Tags

Disertační práce je zaměřena na metody a systémy pro měření vzdálenosti a lokalizaci RFID tagů pracujících v pásmu UHF. Úvod je věnován popisu současného stavu vědeckého poznání v oblasti RFID prostorové identifikace a stručnému shrnutí problematiky modelování a návrhu prototypů těchto systémů. Po specifikaci cílů disertace pokračuje práce popisem teorie modelování degenerovaného kanálu pro RFID komunikaci. Detailně jsou rozebrány metody měření vzdálenosti a odhadu směru příchodu signálu založené na zpracování fázové informace. Pro účely lokalizace je navrženo několik scénářů rozmístění antén. Modely degenerovaného kanálu jsou simulovány v systému MATLAB. Významná část této práce je věnována konceptu softwarově definovaného rádia (SDR) a specifikům jeho adaptace na UHF RFID, která využití běžných SDR systémů značně omezují. Diskutována je zejména problematika průniku nosné vysílače do přijímací cesty a požadavky na signál lokálního oscilátoru používaný pro směšování. Prezentovány jsou tři vyvinuté prototypy: experimentální dotazovač EXIN-1, měřicí systém založený na platformě Ettus USRP a anténní přepínací matice pro emulaci SIMO systému. Závěrečná část je zaměřena na testování a zhodnocení popisovaných lokalizačních technik, založených na měření komplexní přenosové funkce RFID kanálu. Popisuje úzkopásmové/širokopásmové měření vzdálenosti a metody odhadu směru signálu. Oba navržené scénáře rozmístění antén jsou v závěru ověřeny lokalizačním měřením v reálných podmínkách.The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.

A Framework for Seamless Variant Management and Incremental Migration to a Software Product-Line

Context: Software systems often need to exist in many variants in order to satisfy varying customer requirements and operate under varying software and hardware environments. These variant-rich systems are most commonly realized using cloning, a convenient approach to create new variants by reusing existing ones. Cloning is readily available, however, the non-systematic reuse leads to difficult maintenance. An alternative strategy is adopting platform-oriented development approaches, such as Software Product-Line Engineering (SPLE). SPLE offers systematic reuse, and provides centralized control, and thus, easier maintenance. However, adopting SPLE is a risky and expensive endeavor, often relying on significant developer intervention. Researchers have attempted to devise strategies to synchronize variants (change propagation) and migrate from clone&own to an SPL, however, they are limited in accuracy and applicability. Additionally, the process models for SPLE in literature, as we will discuss, are obsolete, and only partially reflect how adoption is approached in industry. Despite many agile practices prescribing feature-oriented software development, features are still rarely documented and incorporated during actual development, making SPL-migration risky and error-prone.Objective: The overarching goal of this PhD is to bridge the gap between clone&own and software product-line engineering in a risk-free, smooth, and accurate manner. Consequently, in the first part of the PhD, we focus on the conceptualization, formalization, and implementation of a framework for migrating from a lean architecture to a platform-based one.Method: Our objectives are met by means of (i) understanding the literature relevant to variant-management and product-line migration and determining the research gaps (ii) surveying the dominant process models for SPLE and comparing them against the contemporary industrial practices, (iii) devising a framework for incremental SPL adoption, and (iv) investigating the benefit of using features beyond PL migration; facilitating model comprehension.Results: Four main results emerge from this thesis. First, we present a qualitative analysis of the state-of-the-art frameworks for change propagation and product-line migration. Second, we compare the contemporary industrial practices with the ones prescribed in the process models for SPL adoption, and provide an updated process model that unifies the two to accurately reflect the real practices and guide future practitioners. Third, we devise a framework for incremental migration of variants into a fully integrated platform by exploiting explicitly recorded metadata pertaining to clone and feature-to-asset traceability. Last, we investigate the impact of using different variability mechanisms on the comprehensibility of various model-related tasks.Future work: As ongoing and future work, we aim to integrate our framework with existing IDEs and conduct a developer study to determine the efficiency and effectiveness of using our framework. We also aim to incorporate safe-evolution in our operators

Queuing analysis and optimization of public vehicle transport stations: A case of South West Ethiopia region vehicle stations

Modern urban environments present a dynamically growing field where, notwithstanding shared goals, several mutually conflicting interests frequently collide. However, it has a big impact on the city's socioeconomic standing, waiting lines and queues are common occurrences. This results in extremely long lines for vehicles and people on incongruous routes, service coagulation, customer murmuring, unhappiness, complaints, and looking for other options, sometimes illegally. The root cause is corruption, which leads to traffic jams, stops and packs vehicles beyond their safe carrying capacity, and violates passengers' human rights and freedoms. This study focused on optimizing the time passengers had to wait in public vehicle stations. This applied research employed both data-gathering sources and mixed approaches. Then, 166 samples of key informants of transport stations were taken using the Slovin sampling formula. The time vehicles, including the drivers and auxiliary drivers ‘Weyala', had to wait was also studied. To maximize the service level at vehicle stations, a queuing model was subsequently devised ‘Menaharya’. Time, cost, and quality encompass performance, scope, and suitability for the intended purposes. The study also focused on determining the minimal response time required for passengers and vehicles queuing to reach their ultimate destinations within the transportation stations in Tepi, Mizan, and Bonga. A new bus station system was modeled and simulated by Arena simulation software in the chosen study area. 84% improvement on cost reduced by 56.25%, time 4 hours to 1.5 hours, quality, safety and designed load performance calculations employed. Stakeholders are asked to implement the model and monitor the results obtained

An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

The 1990 Johnson Space Center bibliography of scientific and technical papers

Abstracts are presented of scientific and technical papers written and/or presented by L. B. Johnson Space Center (JSC) authors, including civil servants, contractors, and grantees, during the calendar year of 1990. Citations include conference and symposium presentations, papers published in proceedings or other collective works, seminars, and workshop results, NASA formal report series (including contractually required final reports), and articles published in professional journals

A systematic comparison of roundtrip software engineering approaches

Model-based software engineering contemplates several software development approaches in which models play an important role. One such approach is round-trip engineering. Very briefly, round-trip engineering is code generation from models, and models are updated whenever a code change occurs. The objective of this dissertation is to benchmark the comparative analysis of the round-trip engineering capability of the UML, Papyrus, Modelio and Visual Paradigm modeling tools. In more detailed terms, the work will focus on evaluating tools to automatically or semi-automatically support round-trip engineering processes for each selected diagram. Collaterally, this dissertation will allow us to gain insight into the current round-trip engineering landscape, establishing the state-of-the-art UML modeling tool support for this approach. Qualitative and quantitative analysis of the round-trip engineering capabilities of the tools show that the Papyrus, Modeling and Visual Paradigm tools yielded satisfactory results by applying the Reverse and Forward Engineering scenarios without changing the models and codes but applying the Round-trip engineering scenario with changes in model and code presented results with some gaps in model and code coherence. It was concluded that they arose because the semantic definition of the models was done informally. The conclusions drawn throughout the dissertation will answer the questions: How effective are current code generation tools for documenting application evolution? Where will it support the decision made? objectives and will support the recommendations of the best tools that address the round-trip engineering method.A engenharia de software baseada em modelo contempla várias abordagens de desenvolvimento de software nas quais os modelos desempenham um papel importante. Uma dessas abordagens é a Round-trip engineering. Muito brevemente, a Round-trip engineering é a geração de código a partir de modelos, e os modelos são atualizado sempre que ocorre uma alteração no código. O objetivo desta dissertação é a realização de um benchmarking da análise comparativa da capacidade de Round-trip engineering das ferramentas de modelação UML, Papyrus, Modelio e Visual Paradigm. Em termos mais detalhados, o trabalho se concentrará na avaliação de ferramentas para dar suporte automático ou semiautomático a processos de Round-trip engineering (engenharia direta e engenharia reversa) para cada diagrama selecionado. Colateralmente, esta dissertação permitirá alcançar uma visão do panorama atual da Round-trip engineering, estabelecendo o estado da arte do suporte de ferramentas de modelação em UML à dita abordagem. A analise qualitativa e quantitativamente da capacidade de Round-trip engineering das ferramentas mostro que, as ferramentas Papiro, Modelagem e Paradigma Visual apresentaram resultados satisfatórios aplicando os cenários de Reverse e Forward Engineering sem alterar os modelos e códigos e com alterações, mas aplicando o cenário Round-trip engineering com alterações nos modelo e código apresentaram resultados com algumas lacunas nomeadamente na coerência dos modelos e código. Concluiu-se que as mesmas surgiram por causa da definição semântica dos modelos ser feita de forma informal. As conclusões tiradas ao longo do trabalho respondera as perguntas: Qual a eficácia das ferramentas atuais de geração de código para documentar a evolução dos aplicativos? Onde apoiará a decisão tomada? que foram definidas nos objetivos e apoiarão as recomendações das melhores ferramentas que aborda o método Round-trip engineering

The implications of digitalization on business model change

Context: Digitalization brings new opportunities and also challenges to software companies. Objective: Software companies have mostly focused on the technical aspects of handing changes and mostly ignoring the business model changes and their implications on software organization and the architecture. In this paper, we synthesize implications of the digitalization based on an extensive literature survey and a longitudinal case study at Ericsson AB. Method: Using thematic analysis, we present six propositions to be used to facilitate the cross-disciplinary analysis of business model dynamics and the effectiveness and efficiency of the outcome of business modeling, by linking value, transaction, and organizational learning to business model change. Conclusions: Business model alignment is highlighted as a new business model research area for understanding the relationships between the dynamic nature of business models, organization design, and the value creation in the business model activities