10,059 research outputs found

    Nineteen Figures and Counting: Contextualization and Conservation Treatment of a Jacob Spoel Painting

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    This study focuses on the research, technical analysis, and treatment of an 1852 Jacob Spoel painting (Untitled, acc.62.28, 80cm H x 105cm W x 1.75cm D) owned by the Memorial Art Gallery and described as a ‘family gathering.’ When received by the department, the painting was not in a fit state for display; it was not structurally sound and had a disfiguring varnish reducing the readability of the composition. Technical research, multimodal imaging, radiography, and instrumental analysis, including x-ray fluorescence spectroscopy, Raman spectroscopy, cross-sectional analysis, and Fourier transform infrared spectroscopy, were carried out to understand the materials and techniques used by the artist. Results played a part in shaping the treatment strategy, and the painting was successfully stabilized and returned to a suitable condition for exhibition

    On the real world practice of Behaviour Driven Development

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    Surveys of industry practice over the last decade suggest that Behaviour Driven Development is a popular Agile practice. For example, 19% of respondents to the 14th State of Agile annual survey reported using BDD, placing it in the top 13 practices reported. As well as potential benefits, the adoption of BDD necessarily involves an additional cost of writing and maintaining Gherkin features and scenarios, and (if used for acceptance testing,) the associated step functions. Yet there is a lack of published literature exploring how BDD is used in practice and the challenges experienced by real world software development efforts. This gap is significant because without understanding current real world practice, it is hard to identify opportunities to address and mitigate challenges. In order to address this research gap concerning the challenges of using BDD, this thesis reports on a research project which explored: (a) the challenges of applying agile and undertaking requirements engineering in a real world context; (b) the challenges of applying BDD specifically and (c) the application of BDD in open-source projects to understand challenges in this different context. For this purpose, we progressively conducted two case studies, two series of interviews, four iterations of action research, and an empirical study. The first case study was conducted in an avionics company to discover the challenges of using an agile process in a large scale safety critical project environment. Since requirements management was found to be one of the biggest challenges during the case study, we decided to investigate BDD because of its reputation for requirements management. The second case study was conducted in the company with an aim to discover the challenges of using BDD in real life. The case study was complemented with an empirical study of the practice of BDD in open source projects, taking a study sample from the GitHub open source collaboration site. As a result of this Ph.D research, we were able to discover: (i) challenges of using an agile process in a large scale safety-critical organisation, (ii) current state of BDD in practice, (iii) technical limitations of Gherkin (i.e., the language for writing requirements in BDD), (iv) challenges of using BDD in a real project, (v) bad smells in the Gherkin specifications of open source projects on GitHub. We also presented a brief comparison between the theoretical description of BDD and BDD in practice. This research, therefore, presents the results of lessons learned from BDD in practice, and serves as a guide for software practitioners planning on using BDD in their projects

    Language Design for Reactive Systems: On Modal Models, Time, and Object Orientation in Lingua Franca and SCCharts

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    Reactive systems play a crucial role in the embedded domain. They continuously interact with their environment, handle concurrent operations, and are commonly expected to provide deterministic behavior to enable application in safety-critical systems. In this context, language design is a key aspect, since carefully tailored language constructs can aid in addressing the challenges faced in this domain, as illustrated by the various concurrency models that prevent the known pitfalls of regular threads. Today, many languages exist in this domain and often provide unique characteristics that make them specifically fit for certain use cases. This thesis evolves around two distinctive languages: the actor-oriented polyglot coordination language Lingua Franca and the synchronous statecharts dialect SCCharts. While they take different approaches in providing reactive modeling capabilities, they share clear similarities in their semantics and complement each other in design principles. This thesis analyzes and compares key design aspects in the context of these two languages. For three particularly relevant concepts, it provides and evaluates lean and seamless language extensions that are carefully aligned with the fundamental principles of the underlying language. Specifically, Lingua Franca is extended toward coordinating modal behavior, while SCCharts receives a timed automaton notation with an efficient execution model using dynamic ticks and an extension toward the object-oriented modeling paradigm

    Block by block: developments in NMR methodology

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    Due to its high information content and a non-destructive nature, NMR is a versatile and widely used analytical technique. A large variety of different NMR experiments exist, each providing specific information about the system being studied. Over the years a number of building blocks of NMR experiments have been designed, with new still appearing. When combined they can address issues such as spectral complexity, low sample concentrations or signal overlap. This thesis presents work in which several NMR building blocks have been modified and combined creatively to enhance their performance and to produce new, powerful NMR experiments. The first building block to be utilised is DISPEL (Destruction of Interfering Satellites by Perfect Echo Low-pass filtration),1 a pulse sequence element that suppresses one-bond 13C satellites in 1D 1H spectra. So far it has been utilised to declutter spectra and identify low concentration impurities in samples. In our work, the DISPEL pulse sequence has been combined with a 2D TOCSY experiment to enable the removal of one-bond 13C satellites in 2D correlation spectra. Through comparisons of four DISPEL-TOCSY spectra that can be obtained by varying when the DISPEL elements are active, it was possible to obtain information about site-specific 13C enrichment within molecules. This work has been applied to a sample of partially 13C-labeled amino acids obtained by a digest of E. coli proteins prepared by using 13C-labeled glucose as the carbon source. The DISPEL pulse sequence has also been combined with the JRES experiment aiding the identification of individual peaks and their multiplicity. This work widens the potential of NMR in studies of metabolic pathways. The second building block explored is the SHARPER (Sensitive, Homogeneous And Resolved PEaks in Real time)2 acquisition technique. This “pure-shift” method removes all heteronuclear and homonuclear couplings from a single signal, reducing the peak to a single singlet with a greatly increased signal to noise ratio, in part due to its inherent capability to compensate for magnetic field inhomogeneity. The original SHARPER pulse sequence was adapted for use on benchtop spectrometers accounting for varying levels of spectrometer hardware and sample requirements. Although equally applicable to high field instruments, this work is particularly beneficial to lower sensitivity, lower magnetic field homogeneity benchtop systems, e. g. for the purpose of reaction monitoring. By shortening the spin-echo intervals and using non-selective pulses, the SHARPER pulse sequence was modified to remove chemical shift dispersion of all, or a selected group of 1H resonances. This produced a possibility of collapsing an entire spectrum into a single intense and narrow signal that can act as a reporter of molecular properties of studied compounds. This modification was used to design a SHARPER-DOSY (Diffusion-Ordered SpectroscopY) pulse sequence for the measurement of diffusion coefficients of pure compounds. When applied to small and medium size molecules, the sensitivity of this experiment is 10 to 100-fold higher than that of the original DOSY experiment. It was demonstrated that using cryogenically cooled probes on high-field NMR spectrometers, ÎŒM sample concentrations, prepared using as little as 1 ÎŒg of a compound, can yield a diffusion coefficient in several minutes. Finally, SHARPER has been combined with a chemical-shift-selective-filter (CSSF), a technique that enables selective excitation of a single multiplet from a heavily overlapped spectral region, with chemical shift differences as small as 1-2 Hz. The CSSF building block was combined with the DOSY experiment to produce a CSSF-SHARPER-DOSY experiment that enables the determination of diffusion coefficients from highly overlapped spectra

    Symmetries of Riemann surfaces and magnetic monopoles

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    This thesis studies, broadly, the role of symmetry in elucidating structure. In particular, I investigate the role that automorphisms of algebraic curves play in three specific contexts; determining the orbits of theta characteristics, influencing the geometry of the highly-symmetric Bring’s curve, and in constructing magnetic monopole solutions. On theta characteristics, I show how to turn questions on the existence of invariant characteristics into questions of group cohomology, compute comprehensive tables of orbit decompositions for curves of genus 9 or less, and prove results on the existence of infinite families of curves with invariant characteristics. On Bring’s curve, I identify key points with geometric significance on the curve, completely determine the structure of the quotients by subgroups of automorphisms, finding new elliptic curves in the process, and identify the unique invariant theta characteristic on the curve. With respect to monopoles, I elucidate the role that the Hitchin conditions play in determining monopole spectral curves, the relation between these conditions and the automorphism group of the curve, and I develop the theory of computing Nahm data of symmetric monopoles. As such I classify all 3-monopoles whose Nahm data may be solved for in terms of elliptic functions

    Analysis and Design of Non-Orthogonal Multiple Access (NOMA) Techniques for Next Generation Wireless Communication Systems

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    The current surge in wireless connectivity, anticipated to amplify significantly in future wireless technologies, brings a new wave of users. Given the impracticality of an endlessly expanding bandwidth, there’s a pressing need for communication techniques that efficiently serve this burgeoning user base with limited resources. Multiple Access (MA) techniques, notably Orthogonal Multiple Access (OMA), have long addressed bandwidth constraints. However, with escalating user numbers, OMA’s orthogonality becomes limiting for emerging wireless technologies. Non-Orthogonal Multiple Access (NOMA), employing superposition coding, serves more users within the same bandwidth as OMA by allocating different power levels to users whose signals can then be detected using the gap between them, thus offering superior spectral efficiency and massive connectivity. This thesis examines the integration of NOMA techniques with cooperative relaying, EXtrinsic Information Transfer (EXIT) chart analysis, and deep learning for enhancing 6G and beyond communication systems. The adopted methodology aims to optimize the systems’ performance, spanning from bit-error rate (BER) versus signal to noise ratio (SNR) to overall system efficiency and data rates. The primary focus of this thesis is the investigation of the integration of NOMA with cooperative relaying, EXIT chart analysis, and deep learning techniques. In the cooperative relaying context, NOMA notably improved diversity gains, thereby proving the superiority of combining NOMA with cooperative relaying over just NOMA. With EXIT chart analysis, NOMA achieved low BER at mid-range SNR as well as achieved optimal user fairness in the power allocation stage. Additionally, employing a trained neural network enhanced signal detection for NOMA in the deep learning scenario, thereby producing a simpler signal detection for NOMA which addresses NOMAs’ complex receiver problem

    A Delphi Study to Strengthen Research-Methods Training in Undergraduate Psychology Programs

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    Psychology programs often emphasize inferential statistical tests over a solid understanding of data and research design. This imbalance may leave graduates underequipped to effectively interpret research and employ data to answer questions. We conducted a two-round modified Delphi to identify the research-methods skills that the UK psychology community deems essential for undergraduates to learn. Participants included 103 research-methods instructors, academics, students, and nonacademic psychologists. Of 78 items included in the consensus process, 34 reached consensus. We coupled these results with a qualitative analysis of 707 open-ended text responses to develop nine recommendations for organizations that accredit undergraduate psychology programs—such as the British Psychological Society. We recommend that accreditation standards emphasize (1) data skills, (2) research design, (3) descriptive statistics, (4) critical analysis, (5) qualitative methods, and (6) both parameter estimation and significance testing; as well as (7) give precedence to foundational skills, (8) promote transferable skills, and (9) create space in curricula to enable these recommendations. Our data and findings can inform modernized accreditation standards to include clearly defined, assessable, and widely encouraged skills that foster a competent graduate body for the contemporary world

    A Delphi study to strengthen research-methods training in undergraduate psychology programs

    Get PDF
    Psychology programs often emphasize inferential statistical tests over a solid understanding of data and research design. This imbalance may leave graduates underequipped to effectively interpret research and employ data to answer questions. We conducted a two-round modified Delphi to identify the research-methods skills that the UK psychology community deems essential for undergraduates to learn. Participants included 103 research-methods instructors, academics, students, and nonacademic psychologists. Of 78 items included in the consensus process, 34 reached consensus. We coupled these results with a qualitative analysis of 707 open-ended text responses to develop nine recommendations for organizations that accredit undergraduate psychology programs—such as the British Psychological Society. We recommend that accreditation standards emphasize (1) data skills, (2) research design, (3) descriptive statistics, (4) critical analysis, (5) qualitative methods, and (6) both parameter estimation and significance testing; as well as (7) give precedence to foundational skills, (8) promote transferable skills, and (9) create space in curricula to enable these recommendations. Our data and findings can inform modernized accreditation standards to include clearly defined, assessable, and widely encouraged skills that foster a competent graduate body for the contemporary world

    FARC musicians' musical identities and political identities through their music: analysis of their narratives, musical practices and songs in the Colombian peace post-agreement

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    The Colombia Revolutionary Army Forces (FARC) was the largest and most important guerrilla movement in the long and persistent Colombian internal armed conflict. In November 2016, after overcoming significant difficulties, the Colombian government and FARC signed and ratified a Final Peace Agreement; nowadays, FARC has become a lawful political party: Los Comunes. For over fifty years, the movement stimulated cultural and musical activities; FARC's musicians created, composed, arranged, recorded, performed and distributed thousands of songs, initially as part of a guerrilla and now as political party members. This research studies the musical identities of FARC musicians and their political identities as constructed through their music, based on social and cultural perspectives from the field of musical identities, the music and social movements theoretical framework and the transformation of conflict approach. This study observes how musical identities are negotiated as a force for transformative political and cultural changes at the personal and collective levels. The FARC musicians' narratives are a primary source for analysing the sociocultural transformation of identities and how they negotiate their musical and political identities. Based on a phenomenological perspective and qualitative methods, this research applied an ethnographic approach and narrative analysis based on the Listening Guide Method (LGM) to undertake a qualitative study of two narratives: life histories and songs-as-narratives. The life histories and the songs-as-narratives can be understood as sociocultural performances with multiple and continuous constructions of selfhood. The analysis of (5) FARC musicians' musical biographies (life histories), obtained through three in-depth semi-structured interviews each, and four (4) songs-as-narratives, based on music video material, allows us to observe the relationship between their music and the social movement and the role of their music in the conflict transformation process. The analysis reveals how the negotiation of musical and political identities interacts mutually and intertwined during conflict transformation experiences involving personal and collective changes. The life histories and song-as-narratives analysis provide evidence about the relationship between Identities in Music (IIM) and their Music in Identities (MII). The IIM and MII are inseparable dimensions of the self. The former is narrated through ex-combatant musicians' experiences as songwriters, singers, instrumentalists, producers, and music teachers committed to their political ideas. The latter emerges in ideological terms, but mainly through personal and collective experiences, emotionally significant, expressing their belonging to the peasantry, indigenous and popular musical cultures. At individual and collective levels, their musical knowledge, interactions and experiences construct new social roles, particularly in transitioning from guerrilla combatants to political party members. The results reveal that music is a sociocultural resource developed by musicians and the entire movement throughout the decades. The ex-combatant musicians' narratives reveal how they employ their musical experiences to explore the possibilities of the moral imagination, changing lyrics, musical production and distribution processes. Exploring new musical genres or affirming their belonging to some of them, they build different social (political) and cultural (musical) realities in their contexts. The transformation of the conflict is a profound identity negotiation process. During the transformation of the conflict, musical and political identities support each other based on ex-combatant musicians' emotional competence or emotional capital, their different uses of "I" and "we", their personal and collective relationships and connections with broader socioeconomic, political and cultural structures

    Resource-aware scheduling for 2D/3D multi-/many-core processor-memory systems

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    This dissertation addresses the complexities of 2D/3D multi-/many-core processor-memory systems, focusing on two key areas: enhancing timing predictability in real-time multi-core processors and optimizing performance within thermal constraints. The integration of an increasing number of transistors into compact chip designs, while boosting computational capacity, presents challenges in resource contention and thermal management. The first part of the thesis improves timing predictability. We enhance shared cache interference analysis for set-associative caches, advancing the calculation of Worst-Case Execution Time (WCET). This development enables accurate assessment of cache interference and the effectiveness of partitioned schedulers in real-world scenarios. We introduce TCPS, a novel task and cache-aware partitioned scheduler that optimizes cache partitioning based on task-specific WCET sensitivity, leading to improved schedulability and predictability. Our research explores various cache and scheduling configurations, providing insights into their performance trade-offs. The second part focuses on thermal management in 2D/3D many-core systems. Recognizing the limitations of Dynamic Voltage and Frequency Scaling (DVFS) in S-NUCA many-core processors, we propose synchronous thread migrations as a thermal management strategy. This approach culminates in the HotPotato scheduler, which balances performance and thermal safety. We also introduce 3D-TTP, a transient temperature-aware power budgeting strategy for 3D-stacked systems, reducing the need for Dynamic Thermal Management (DTM) activation. Finally, we present 3QUTM, a novel method for 3D-stacked systems that combines core DVFS and memory bank Low Power Modes with a learning algorithm, optimizing response times within thermal limits. This research contributes significantly to enhancing performance and thermal management in advanced processor-memory systems
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