Early aspects: aspect-oriented requirements engineering and architecture design

This paper reports on the third Early Aspects: Aspect-Oriented Requirements Engineering and Architecture Design Workshop, which has been held in Lancaster, UK, on March 21, 2004. The workshop included a presentation session and working sessions in which the particular topics on early aspects were discussed. The primary goal of the workshop was to focus on challenges to defining methodical software development processes for aspects from early on in the software life cycle and explore the potential of proposed methods and techniques to scale up to industrial applications

Perception-motivated parallel algorithms for haptics

Negli ultimi anni l\u2019utilizzo di dispositivi aptici, atti cio\ue8 a riprodurre l\u2019interazione fisica con l\u2019ambiente remoto o virtuale, si sta diffondendo in vari ambiti della robotica e dell\u2019informatica, dai videogiochi alla chirurgia robotizzata eseguita in teleoperazione, dai cellulari alla riabilitazione. In questo lavoro di tesi abbiamo voluto considerare nuovi punti di vista sull\u2019argomento, allo scopo di comprendere meglio come riportare l\u2019essere umano, che \ue8 l\u2019unico fruitore del ritorno di forza, tattile e di telepresenza, al centro della ricerca sui dispositivi aptici. Allo scopo ci siamo focalizzati su due aspetti: una manipolazione del segnale di forza mutuata dalla percezione umana e l\u2019utilizzo di architetture multicore per l\u2019implementazione di algoritmi aptici e robotici. Con l\u2019aiuto di un setup sperimentale creato ad hoc e attraverso l\u2019utilizzo di un joystick con ritorno di forza a 6 gradi di libert\ue0, abbiamo progettato degli esperimenti psicofisici atti all\u2019identificazione di soglie differenziali di forze/coppie nel sistema mano-braccio. Sulla base dei risultati ottenuti abbiamo determinato una serie di funzioni di scalatura del segnale di forza, una per ogni grado di libert\ue0, che permettono di aumentare l\u2019abilit\ue0 umana nel discriminare stimoli differenti. L\u2019utilizzo di tali funzioni, ad esempio in teleoperazione, richiede la possibilit\ue0 di variare il segnale di feedback e il controllo del dispositivo sia in relazione al lavoro da svolgere, sia alle peculiari capacit\ue0 dell\u2019utilizzatore. La gestione del dispositivo deve quindi essere in grado di soddisfare due obbiettivi tendenzialmente in contrasto, e cio\ue8 il raggiungimento di alte prestazioni in termini di velocit\ue0, stabilit\ue0 e precisione, abbinato alla flessibilit\ue0 tipica del software. Una soluzione consiste nell\u2019affidare il controllo del dispositivo ai nuovi sistemi multicore che si stanno sempre pi\uf9 prepotentemente affacciando sul panorama informatico. Per far ci\uf2 una serie di algoritmi consolidati deve essere portata su sistemi paralleli. In questo lavoro abbiamo dimostrato che \ue8 possibile convertire facilmente vecchi algoritmi gi\ue0 implementati in hardware, e quindi intrinsecamente paralleli. Un punto da definire rimane per\uf2 quanto costa portare degli algoritmi solitamente descritti in VLSI e schemi in un linguaggio di programmazione ad alto livello. Focalizzando la nostra attenzione su un problema specifico, la pseudoinversione di matrici che \ue8 presente in molti algoritmi di dinamica e cinematica, abbiamo mostrato che un\u2019attenta progettazione e decomposizione del problema permette una mappatura diretta sulle unit\ue0 di calcolo disponibili. In aggiunta, l\u2019uso di parallelismo a livello di dati su macchine SIMD permette di ottenere buone prestazioni utilizzando semplici operazioni vettoriali come addizioni e shift. Dato che di solito tali istruzioni fanno parte delle implementazioni hardware la migrazione del codice risulta agevole. Abbiamo testato il nostro approccio su una Sony PlayStation 3 equipaggiata con un processore IBM Cell Broadband Engine.In the last years the use of haptic feedback has been used in several applications, from mobile phones to rehabilitation, from video games to robotic aided surgery. The haptic devices, that are the interfaces that create the stimulation and reproduce the physical interaction with virtual or remote environments, have been studied, analyzed and developed in many ways. Every innovation in the mechanics, electronics and technical design of the device it is valuable, however it is important to maintain the focus of the haptic interaction on the human being, who is the only user of force feedback. In this thesis we worked on two main topics that are relevant to this aim: a perception based force signal manipulation and the use of modern multicore architectures for the implementation of the haptic controller. With the help of a specific experimental setup and using a 6 dof haptic device we designed a psychophysical experiment aimed at identifying of the force/torque differential thresholds applied to the hand-arm system. On the basis of the results obtained we determined a set of task dependent scaling functions, one for each degree of freedom of the three-dimensional space, that can be used to enhance the human abilities in discriminating different stimuli. The perception based manipulation of the force feedback requires a fast, stable and configurable controller of the haptic interface. Thus a solution is to use new available multicore architectures for the implementation of the controller, but many consolidated algorithms have to be ported to these parallel systems. Focusing on specific problem, i.e. the matrix pseudoinversion, that is part of the robotics dynamic and kinematic computation, we showed that it is possible to migrate code that was already implemented in hardware, and in particular old algorithms that were inherently parallel and thus not competitive on sequential processors. The main question that still lies open is how much effort is required in order to write these algorithms, usually described in VLSI or schematics, in a modern programming language. We show that a careful task decomposition and design permit a mapping of the code on the available cores. In addition, the use of data parallelism on SIMD machines can give good performance when simple vector instructions such as add and shift operations are used. Since these instructions are present also in hardware implementations the migration can be easily performed. We tested our approach on a Sony PlayStation 3 game console equipped with IBM Cell Broadband Engine processor

A study of children learning multicolumn addition with microcomputer software support.

Three computer-aided tutoring procedures were devised to teach multicolumn addition according to the standard school algorithm, one procedure to each of three groups of 2nd-grade children. The key differences between groups were the demands placed on short term memory and the amount of conceptual understanding the procedures attempted to teach. Each child solved a sequence of two-digit problems on a computer screen by touching each digit with a light pen in the correct sequence. The control group did not receive on-screen number-fact assistance. One treatment ( assisted ) group did receive on-screen number-fact assistance, testing the hypothesis that the algorithm is learned more effectively when learned first as a sequence of procedural steps alone, without subjects\u27 need to recall number-facts. A second treatment ( simulation ) group received the same on-screen assistance along with an additional display of simulated blocks which, like concrete manipulative materials, represented symbol manipulations. The simulation group tested a second hypothesis that a concurrent display of the meaning of procedural steps contributes to even more effective algorithmic learning. T-tests (one-tailed, 5% level) applied pair-wise to pretest/posttest difference scores indicated support for the first hypothesis but not for the second, an indication that 2nd-grade children learn the addition algorithm more effectively if demand on short term memory is temporarily lifted. A descriptive framework called superposition of frames is proposed to account for anomalies in findings and for the rich diversity of errors generally manifested by children in multidigit addition. Drawing on current concepts in cognitive psychology and mathematics education, this description suggests that children\u27s mathematical knowledge is fragmented into isolated, unstable, and sometimes entrenched frames of knowledge. When a child finds appropriate correspondences between frames and initiates a superposition of frames, the child\u27s procedural and conceptual knowledge, previously in disarray, may then become integrated. Implications for elementary mathematics instruction are discussed

Energy efficient hardware acceleration of multimedia processing tools

The world of mobile devices is experiencing an ongoing trend of feature enhancement and generalpurpose multimedia platform convergence. This trend poses many grand challenges, the most pressing being their limited battery life as a consequence of delivering computationally demanding features. The envisaged mobile application features can be considered to be accelerated by a set of underpinning hardware blocks Based on the survey that this thesis presents on modem video compression standards and their associated enabling technologies, it is concluded that tight energy and throughput constraints can still be effectively tackled at algorithmic level in order to design re-usable optimised hardware acceleration cores. To prove these conclusions, the work m this thesis is focused on two of the basic enabling technologies that support mobile video applications, namely the Shape Adaptive Discrete Cosine Transform (SA-DCT) and its inverse, the SA-IDCT. The hardware architectures presented in this work have been designed with energy efficiency in mind. This goal is achieved by employing high level techniques such as redundant computation elimination, parallelism and low switching computation structures. Both architectures compare favourably against the relevant pnor art in the literature. The SA-DCT/IDCT technologies are instances of a more general computation - namely, both are Constant Matrix Multiplication (CMM) operations. Thus, this thesis also proposes an algorithm for the efficient hardware design of any general CMM-based enabling technology. The proposed algorithm leverages the effective solution search capability of genetic programming. A bonus feature of the proposed modelling approach is that it is further amenable to hardware acceleration. Another bonus feature is an early exit mechanism that achieves large search space reductions .Results show an improvement on state of the art algorithms with future potential for even greater savings

Business Governance Best Practices of Virtual Project Teams

The steady increase in project failure rates is leaving businesses searching for better integration techniques to virtualize their project environments. Through virtualization, organizations may have positive impacts on communities across geographical boundaries and resource constraints. The focus of this phenomenological study was to explore, via the experiences of successful project management practitioners, best practice strategies for integrating virtual project teams through data analysis. The conceptual framework included von Bertalanffy\u27s general systems theory, decomposition model of business process and project management frameworks, and the recomposition approach. Twenty-two senior project managers with more than 5 years of experience managing virtual project environments participated in semistructured telephone interviews. The van Kaam process employing normalization and bracketing approaches in data analysis resulted in the emergence of 10 thematic categories. The 10 themes culminated in the identification of strategies for implementing best practices relevant to the integration of successful virtual project teams. The major themes pertained to 3 broad areas: (a) structure that accommodates skills and technology for virtual team success, (b) governance leading to efficient virtual project team management, and (c) collaboration practices across diverse environments. Findings may help leaders improve project management leadership practices involved in adopting a virtual project management framework for business infrastructure. Suggestions for future research include additional attention to virtualization problems with respect to the transferability of the systems theory models

Algorithmic Reason

Are algorithms ruling the world today? Is artificial intelligence making life-and-death decisions? Are social media companies able to manipulate elections? As we are confronted with public and academic anxieties about unprecedented changes, this book offers a different analytical prism to investigate these transformations as more mundane and fraught. Aradau and Blanke develop conceptual and methodological tools to understand how algorithmic operations shape the government of self and other. While disperse and messy, these operations are held together by an ascendant algorithmic reason. Through a global perspective on algorithmic operations, the book helps us understand how algorithmic reason redraws boundaries and reconfigures differences. The book explores the emergence of algorithmic reason through rationalities, materializations, and interventions. It traces how algorithmic rationalities of decomposition, recomposition, and partitioning are materialized in the construction of dangerous others, the power of platforms, and the production of economic value. The book shows how political interventions to make algorithms governable encounter friction, refusal, and resistance. The theoretical perspective on algorithmic reason is developed through qualitative and digital methods to investigate scenes and controversies that range from mass surveillance and the Cambridge Analytica scandal in the UK to predictive policing in the US, and from the use of facial recognition in China and drone targeting in Pakistan to the regulation of hate speech in Germany. Algorithmic Reason offers an alternative to dystopia and despair through a transdisciplinary approach made possible by the authors’ backgrounds, which span the humanities, social sciences, and computer sciences

Insightful analysis of historical sources at scales beyond human capabilities using unsupervised Machine Learning and XAI

Historical materials are abundant. Yet, piecing together how human knowledge has evolved and spread both diachronically and synchronically remains a challenge that can so far only be very selectively addressed. The vast volume of materials precludes comprehensive studies, given the restricted number of human specialists. However, as large amounts of historical materials are now available in digital form there is a promising opportunity for AI-assisted historical analysis. In this work, we take a pivotal step towards analyzing vast historical corpora by employing innovative machine learning (ML) techniques, enabling in-depth historical insights on a grand scale. Our study centers on the evolution of knowledge within the `Sacrobosco Collection' -- a digitized collection of 359 early modern printed editions of textbooks on astronomy used at European universities between 1472 and 1650 -- roughly 76,000 pages, many of which contain astronomic, computational tables. An ML based analysis of these tables helps to unveil important facets of the spatio-temporal evolution of knowledge and innovation in the field of mathematical astronomy in the period, as taught at European universities

Laser powder bed fusion-centred approach to enable local drug delivery from a cementless hip stem

ENGLISH ABSTRACT: Periprosthetic joint infection (PJI) resulting from colonisation of implant surfaces by pathogenic bacteria and subsequent biofilm formation is a devastating complication following total hip arthroplasty. It significantly reduces a patient’s quality of life and, in severe cases, can result in amputation or mortality. Treatment of PJI is associated with a substantial burden on healthcare and economic resources. The importance of research towards innovations in PJI prevention and treatment is emphasised. Local delivery of antimicrobial drugs is an effective approach to prevent and treat PJI as it enables high local drug concentrations while avoiding systemic side effects. Current practice is considered sub-optimal and appreciable research exists on the improvement of local drug delivery strategies. For cementless hip stems the focus tends to be on coatings and conditioning of the external implant surface. A significant research gap exists between external and internal drug delivery strategies where ‘internal’ refers to the incorporation of reservoir structures within the implant. Therefore, a prototype strategy utilising the internal volume of a cementless stem for a reservoir from which an antimicrobial drug can be delivered directly to the implant surface was investigated. The challenge of fabricating a cementless hip stem with intricate internal geometries can be effectively addressed through metal additive manufacturing (MAM). Industry is steadily incorporating MAM into process chains as the main production technology for the fabrication of high-value functional components. Laser powder bed fusion (LPBF) was applied in this study as MAM technology to fabricate a Ti6Al4V ELI demonstrator cementless hip stem with local drug delivery functionality. This required an interdisciplinary approach, for which a problem solving framework has been synthesised to aid in process chain development from an LPBF-centred perspective. The overall problem was decomposed into integrated partial and single problems which were systematically investigated through literature study and experimentation. An LPBF-centred solution was developed for the direct integration of permeable structures in a dense part using an in-process assembly method. Different levels of porosity were induced into permeable thin walls according to a systematically identified window for ranges of the process parameters, laser power and scanning speed. This resulted in tailorable release profiles for the model antibiotic vancomycin from an aqueous formulation. Released vancomycin retained its antibiotic efficacy against Staphylococcus aureus Xen 36 (methicillin sensitive) and Staphylococcus aureus Xen 31 (methicillin resistant), representing two of the most frequent pathogens in PJI. Solutions for single problems were recomposed for integrated solutions to partial problems, and subsequently for an overall prototype solution. The overall solution cementless hip stem prototype effectively prevented surface colonisation by Staphylococcus aureus Xen 31, confirming the efficacy of the developed local drug delivery strategy. These results were used to inductively refine the LPBF-centred interdisciplinary problem solving framework. The original contribution of the research corresponds to the experimentation and framework development phases respectively. This involves the systematic investigation of LPBF to enable local drug delivery and an LPBF-centred approach for interdisciplinary problem solving. Lastly, it contributes to the advancement of LPBF by demonstrating the application efficacy of the prototype solution.AFRIKAANSE OPSOMMIMG: Periprostetiese gewrigsinfeksie (PJI) as ‘n gevolg van implantaatoppervlak kolonisasie deur patogeniese bakterieë en biofilm formasie is ’n ernstige komplikasie na totale heupartroplastiek. Dit verlaag ’n pasiënt se lewenskwaliteit merkwaardig en kan in ernstige gevalle lei tot amputasie of sterfte. Behandeling van PJI word geassosieer met ’n substansiële las op gesondheids- en ekonomiese middele. Die belangrikheid van navorsing vir innovasies in PJI voorkoming en behandeling word benadruk. Lokale toediening van antimikrobiese medikamente is ‘n effektiewe benadering om PJI te voorkom en te behandel deurdat hoë lokale antimikrobiese konsentrasies gehandhaaf kan word sonder sistemiese newe- effekte. Huidige praktyk word beskou as suboptimaal en veel navorsing bestaan vir die verbetering van lokale toedieningsstrategieë. Vir ongesementeerde heupstamme is die fokus op bedekkings en kondisionering van die eksterne implantaatoppervlak. ’n Beduidende gaping bestaan tussen eksterne en interne lokale toedieningsstrategieë waar ‘intern’ verwys na die inkorporasie van reservoirstrukture binne die implantaat. Daarom was ’n prototipestrategie vir die benutting van die interne volume van ’n ongesementeerde heupstam vir ’n reservoir waar vanuit medikamente direk na die implantaatoppervlak toegedien kan word ondersoek. Die uitdaging om ’n ongesementeerde heupstam met ingewikkelde interne geometrieë te vervaardig kan effektief aangespreek word deur metaal toevoegingsvervaardiging (MAM). ndustrie is stelselmatig besig om MAM in proseskettings te inkorporeer as die hoof produksietegnologie vir die vervaardiging van hoë-waarde funksionele komponente. Laser poeierbed fusie (LPBF) is toegepas in hierdie studie as MAM-tegnologie om ’n Ti6Al4V ELI demonstrasie ongesementeerde heupstam met lokale medikament toedieningsfunksie te vervaardig. Dit het ’n interdissiplinêre benadering vereis waarvoor ’n probleemoplossingsraamwerk gesintetiseer was om die proseskettingontwikkeling vanuit ’n LPBF-gesentreerde perspektief te ondersteun. Die algehele probleem was opgebreek in geïntegreerde deel- en enkelprobleme wat sistematies ondersoek was deur literatuur studie en eksperimentasie. ’n LPBF-gesentreerde oplossing was ontwikkel vir die direkte integrasie van poreuse strukture in ’n digte part met ’n in-proses monteermetode. Verskeie vlakke van porositeit was geïnduseer in deurlaatbare dun wande volgens ’n stelselmatige geïdentifiseerde venster vir waardes vir die prosesparameters laser sterkte en skandeer spoed. Dit het geresulteer in aanpasbare vrystellingsprofiele vir die modelantibiotika vankomisien vanuit ’n wateroplossing. Vrygestelde vankomisien het antibiotiese effektiwiteit behou teen Staphylococcus aureus Xen 36 (metisillien sensitief) en Staphylococcus aureus Xen 31 (metisillien weerstandig), verteenwoordigend van twee van die mees frekwente patogene in PJI. Oplossings vir enkelprobleme was geherkombineer tot geïntegreerde oplossings vir deelprobleme, en gevolglik vir ’n algehele prototipe-oplossing. Die algehele oplossing ongesementeerde heupstam prototipe het oppervlakkolonisasie deur Staphylococcus aureus Xen 31 effektief verhoed wat die funksionaliteit van die ontwikkelde lokale medikament toedieningsstrategie bevestig. Die resultate was induktief gebruik om die LPBF-gesentreerde interdissplinêre probleemoplossingsraamwerk te verfyn. Die oorspronklike bydrae van die navorsing korrespondeer respektiewelik tot die eksperimentele- en raamwerkontwikkelingsfases. Dit betrek die sistematiese ondersoek van LPBF om lokale medikamenttoediening te bewerkstellig en ’n LPBF-gesentreerde raamwerk vir interdissiplinêre probleemoplossing. Laastens dra dit by tot die bevordering van LPBF deur die toepassingseffektiwiteit van die prototipe-oplossing te demonstreer.Doctora