677 resultados para abstraction
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Un dels monuments més vistos pels turistes que van a Barcelona és la Sagrada Família. No és excepció: qualsevol lloc que visitem sens dubte amaga un monument religiós digne de ser vist: el monestir d'El Escorial; el Sagrat Cor de París; els temples hindús d'Ellora; l'estupa budista de Boudhanath a Kàtmandu; el mur de les Lamentacions i la mesquita d'Al-Aqsa a Jerusalem... Per què totes les cultures han tingut i tenen creences religioses, al marge de l'aparent augment de persones que es declaren agnòstiques o atees? És només una construcció cultural o el nostre cervell hi té alguna cosa a veure? I si fos així, tenir creences religioses té algun valor adaptatiu?
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This thesis is done as a complementary part for the active magnet bearing (AMB) control software development project in Lappeenranta University of Technology. The main focus of the thesis is to examine an idea of a real-time operating system (RTOS) framework that operates in a dedicated digital signal processor (DSP) environment. General use real-time operating systems do not necessarily provide sufficient platform for periodic control algorithm utilisation. In addition, application program interfaces found in real-time operating systems are commonly non-existent or provided as chip-support libraries, thus hindering platform independent software development. Hence, two divergent real-time operating systems and additional periodic extension software with the framework design are examined to find solutions for the research problems. The research is discharged by; tracing the selected real-time operating system, formulating requirements for the system, and designing the real-time operating system framework (OSFW). The OSFW is formed by programming the framework and conjoining the outcome with the RTOS and the periodic extension. The system is tested and functionality of the software is evaluated in theoretical context of the Rate Monotonic Scheduling (RMS) theory. The performance of the OSFW and substance of the approach are discussed in contrast to the research theme. The findings of the thesis demonstrates that the forged real-time operating system framework is a viable groundwork solution for periodic control applications.
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Technology scaling has proceeded into dimensions in which the reliability of manufactured devices is becoming endangered. The reliability decrease is a consequence of physical limitations, relative increase of variations, and decreasing noise margins, among others. A promising solution for bringing the reliability of circuits back to a desired level is the use of design methods which introduce tolerance against possible faults in an integrated circuit. This thesis studies and presents fault tolerance methods for network-onchip (NoC) which is a design paradigm targeted for very large systems-onchip. In a NoC resources, such as processors and memories, are connected to a communication network; comparable to the Internet. Fault tolerance in such a system can be achieved at many abstraction levels. The thesis studies the origin of faults in modern technologies and explains the classification to transient, intermittent and permanent faults. A survey of fault tolerance methods is presented to demonstrate the diversity of available methods. Networks-on-chip are approached by exploring their main design choices: the selection of a topology, routing protocol, and flow control method. Fault tolerance methods for NoCs are studied at different layers of the OSI reference model. The data link layer provides a reliable communication link over a physical channel. Error control coding is an efficient fault tolerance method especially against transient faults at this abstraction level. Error control coding methods suitable for on-chip communication are studied and their implementations presented. Error control coding loses its effectiveness in the presence of intermittent and permanent faults. Therefore, other solutions against them are presented. The introduction of spare wires and split transmissions are shown to provide good tolerance against intermittent and permanent errors and their combination to error control coding is illustrated. At the network layer positioned above the data link layer, fault tolerance can be achieved with the design of fault tolerant network topologies and routing algorithms. Both of these approaches are presented in the thesis together with realizations in the both categories. The thesis concludes that an optimal fault tolerance solution contains carefully co-designed elements from different abstraction levels
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The design methods and languages targeted to modern System-on-Chip designs are facing tremendous pressure of the ever-increasing complexity, power, and speed requirements. To estimate any of these three metrics, there is a trade-off between accuracy and abstraction level of detail in which a system under design is analyzed. The more detailed the description, the more accurate the simulation will be, but, on the other hand, the more time consuming it will be. Moreover, a designer wants to make decisions as early as possible in the design flow to avoid costly design backtracking. To answer the challenges posed upon System-on-chip designs, this thesis introduces a formal, power aware framework, its development methods, and methods to constraint and analyze power consumption of the system under design. This thesis discusses on power analysis of synchronous and asynchronous systems not forgetting the communication aspects of these systems. The presented framework is built upon the Timed Action System formalism, which offer an environment to analyze and constraint the functional and temporal behavior of the system at high abstraction level. Furthermore, due to the complexity of System-on-Chip designs, the possibility to abstract unnecessary implementation details at higher abstraction levels is an essential part of the introduced design framework. With the encapsulation and abstraction techniques incorporated with the procedure based communication allows a designer to use the presented power aware framework in modeling these large scale systems. The introduced techniques also enable one to subdivide the development of communication and computation into own tasks. This property is taken into account in the power analysis part as well. Furthermore, the presented framework is developed in a way that it can be used throughout the design project. In other words, a designer is able to model and analyze systems from an abstract specification down to an implementable specification.
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The 3-methylindole (3MI) oxygenation sensitized by psoralen (PSO) has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx) mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1) is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1) suggests that hydrogen abstraction is involved in the rate determining step. A high dependence of the chemical rate constant on water concentration in H2O/Dx mixtures was found showing that water molecules are absolutely essential for the success of the 3MI substrate oxidation by ¹O2* in water-rich solvent mixtures.
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The triplet excited state of xanthone was generated and characterized by laser flash photolysis in acetonitrile (λmax=620 nm; t=1.8 ms) and in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [bmim.PF6] (λmax=620 nm; t=3.0 ms). It reacts with phenols yielding the corresponding xanthone ketyl radical. Stern-Volmer plots for the reaction of triplet xanthone with phenols led to the determination of absolute rate constants for phenolic hydrogen abstraction in the order of ~10(9) Lmol-1s-1 in acetonitrile and ~10(8) Lmol-1s-1 in [bmim.PF6]. The lower diffusioncontrolled rate constant for [bmim.PF6] is responsible for the difference in the phenolic hydrogen abstraction rate constants in this solvent.
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Tämän tutkimuksen tavoitteena oli löytää vastauksia siihen, mikä on tärkeimpien avoimen lähdekoodin kirjastojen toteutuksen tämän hetkinen taso. Työssä tutkittiin WxWidgetsin, GTK+:n ja Qt:n toteutuksen tasoa käytämällä hyväksi McCaben, Henry&Kafuran ja Chidamberin & Kemererin esittelemiä staattisia menetelmiä. Lisäksi ikkunointikirjastojen lähdekoodin käännetty koko mitattiin eri käyttöjärjestelmissä. Tutkimuksessa esitellään valittujen kirjastojen arkkitehtuuri ja vertaillaan esiteltävien kirjastojen arkkitehtuurisia ratkaisuja toisiinsa. Tämän jälkeen arvioidaan staattisten menetelmien tuottamien tuloksien merkitystä kahdesta näkökulmasta: mitä tulokset kertovat kirjastoista kun niitä verrataan toisiinsa ja mitä silloin kun niitä verrataan kyseisen kirjaston ja muiden kirjastojen arkkitehtuurisiin ratkaisuihin. Tutkimuksessa havaittiin Qt:n sisältävän kaikkein vähiten kirjaston ulkopuolisia riippuvuuksia. Tämän lisäksi sen huomattiin sisältävän muista kirjastoista puuttuvia ominaisuuksia. Osittain edellämainitusta syystä johtuen Qt:n ongelmakohdaksi havaittiin joidenkin sen osien suuri monimutkaisuus ja tästä seuraava mahdollinen vaikeasti ylläpidettävä lähdekoodi. GTK+:n lähdekoodi sisältää muita kirjastoja vähemmän sisäisiä riippuvuuksia samaan kirjastoon, on korkeammalla abstraktiotasolla ja kirjaston osat ovat siirrettävissä ja erotettavissa toisistaan. Joissakin kohdissa GTK+:n ja etenkin sen C++-rajapinnan GTKmm:n lähdekoodi on kuitenkin tarpeettoman monimutkaista. WxWidgetsin toteutuksen havaittiin Qt:n tavoin olevan hyvin itsenäinen kokonaisuus, WxWidgetsin lähdekoodin monimutkaisuus on useimmiten jotakin GTK+:n ja Qt:n väliltä. WxWidgets on Qt:a vähemmän itsenäinen mutta kuitenkin itsenäisempi kuin GTK+. Kuten muutkin kirjastot myös wxWidgetsillä on omat kohtansa, joissa sen lähdekoodi on tarpeettoman monimutkaista.
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Systems biology is a new, emerging and rapidly developing, multidisciplinary research field that aims to study biochemical and biological systems from a holistic perspective, with the goal of providing a comprehensive, system- level understanding of cellular behaviour. In this way, it addresses one of the greatest challenges faced by contemporary biology, which is to compre- hend the function of complex biological systems. Systems biology combines various methods that originate from scientific disciplines such as molecu- lar biology, chemistry, engineering sciences, mathematics, computer science and systems theory. Systems biology, unlike “traditional” biology, focuses on high-level concepts such as: network, component, robustness, efficiency, control, regulation, hierarchical design, synchronization, concurrency, and many others. The very terminology of systems biology is “foreign” to “tra- ditional” biology, marks its drastic shift in the research paradigm and it indicates close linkage of systems biology to computer science. One of the basic tools utilized in systems biology is the mathematical modelling of life processes tightly linked to experimental practice. The stud- ies contained in this thesis revolve around a number of challenges commonly encountered in the computational modelling in systems biology. The re- search comprises of the development and application of a broad range of methods originating in the fields of computer science and mathematics for construction and analysis of computational models in systems biology. In particular, the performed research is setup in the context of two biolog- ical phenomena chosen as modelling case studies: 1) the eukaryotic heat shock response and 2) the in vitro self-assembly of intermediate filaments, one of the main constituents of the cytoskeleton. The range of presented approaches spans from heuristic, through numerical and statistical to ana- lytical methods applied in the effort to formally describe and analyse the two biological processes. We notice however, that although applied to cer- tain case studies, the presented methods are not limited to them and can be utilized in the analysis of other biological mechanisms as well as com- plex systems in general. The full range of developed and applied modelling techniques as well as model analysis methodologies constitutes a rich mod- elling framework. Moreover, the presentation of the developed methods, their application to the two case studies and the discussions concerning their potentials and limitations point to the difficulties and challenges one encounters in computational modelling of biological systems. The problems of model identifiability, model comparison, model refinement, model inte- gration and extension, choice of the proper modelling framework and level of abstraction, or the choice of the proper scope of the model run through this thesis.
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Memristive computing refers to the utilization of the memristor, the fourth fundamental passive circuit element, in computational tasks. The existence of the memristor was theoretically predicted in 1971 by Leon O. Chua, but experimentally validated only in 2008 by HP Labs. A memristor is essentially a nonvolatile nanoscale programmable resistor — indeed, memory resistor — whose resistance, or memristance to be precise, is changed by applying a voltage across, or current through, the device. Memristive computing is a new area of research, and many of its fundamental questions still remain open. For example, it is yet unclear which applications would benefit the most from the inherent nonlinear dynamics of memristors. In any case, these dynamics should be exploited to allow memristors to perform computation in a natural way instead of attempting to emulate existing technologies such as CMOS logic. Examples of such methods of computation presented in this thesis are memristive stateful logic operations, memristive multiplication based on the translinear principle, and the exploitation of nonlinear dynamics to construct chaotic memristive circuits. This thesis considers memristive computing at various levels of abstraction. The first part of the thesis analyses the physical properties and the current-voltage behaviour of a single device. The middle part presents memristor programming methods, and describes microcircuits for logic and analog operations. The final chapters discuss memristive computing in largescale applications. In particular, cellular neural networks, and associative memory architectures are proposed as applications that significantly benefit from memristive implementation. The work presents several new results on memristor modeling and programming, memristive logic, analog arithmetic operations on memristors, and applications of memristors. The main conclusion of this thesis is that memristive computing will be advantageous in large-scale, highly parallel mixed-mode processing architectures. This can be justified by the following two arguments. First, since processing can be performed directly within memristive memory architectures, the required circuitry, processing time, and possibly also power consumption can be reduced compared to a conventional CMOS implementation. Second, intrachip communication can be naturally implemented by a memristive crossbar structure.
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The modern society is getting increasingly dependent on software applications. These run on processors, use memory and account for controlling functionalities that are often taken for granted. Typically, applications adjust the functionality in response to a certain context that is provided or derived from the informal environment with various qualities. To rigorously model the dependence of an application on a context, the details of the context are abstracted and the environment is assumed stable and fixed. However, in a context-aware ubiquitous computing environment populated by autonomous agents, a context and its quality parameters may change at any time. This raises the need to derive the current context and its qualities at runtime. It also implies that a context is never certain and may be subjective, issues captured by the context’s quality parameter of experience-based trustworthiness. Given this, the research question of this thesis is: In what logical topology and by what means may context provided by autonomous agents be derived and formally modelled to serve the context-awareness requirements of an application? This research question also stipulates that the context derivation needs to incorporate the quality of the context. In this thesis, we focus on the quality of context parameter of trustworthiness based on experiences having a level of certainty and referral experiences, thus making trustworthiness reputation based. Hence, in this thesis we seek a basis on which to reason and analyse the inherently inaccurate context derived by autonomous agents populating a ubiquitous computing environment in order to formally model context-awareness. More specifically, the contribution of this thesis is threefold: (i) we propose a logical topology of context derivation and a method of calculating its trustworthiness, (ii) we provide a general model for storing experiences and (iii) we formalise the dependence between the logical topology of context derivation and its experience-based trustworthiness. These contributions enable abstraction of a context and its quality parameters to a Boolean decision at runtime that may be formally reasoned with. We employ the Action Systems framework for modelling this. The thesis is a compendium of the author’s scientific papers, which are republished in Part II. Part I introduces the field of research by providing the mending elements for the thesis to be a coherent introduction for addressing the research question. In Part I we also review a significant body of related literature in order to better illustrate our contributions to the research field.
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Abstract—This paper discusses existing military capability models and proposes a comprehensive capability meta-model (CCMM) which unites the existing capability models into an integrated and hierarchical whole. The Zachman Framework for Enterprise Architecture is used as a structure for the CCMM. The CCMM takes into account the abstraction level, the primary area of application, stakeholders, intrinsic process, and life cycle considerations of each existing capability model, and shows how the models relate to each other. The validity of the CCMM was verified through a survey of subject matter experts. The results suggest that the CCMM is of practical value to various capability stakeholders in many ways, such as helping to improve communication between the different capability communities.
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Today's networked systems are becoming increasingly complex and diverse. The current simulation and runtime verification techniques do not provide support for developing such systems efficiently; moreover, the reliability of the simulated/verified systems is not thoroughly ensured. To address these challenges, the use of formal techniques to reason about network system development is growing, while at the same time, the mathematical background necessary for using formal techniques is a barrier for network designers to efficiently employ them. Thus, these techniques are not vastly used for developing networked systems. The objective of this thesis is to propose formal approaches for the development of reliable networked systems, by taking efficiency into account. With respect to reliability, we propose the architectural development of correct-by-construction networked system models. With respect to efficiency, we propose reusable network architectures as well as network development. At the core of our development methodology, we employ the abstraction and refinement techniques for the development and analysis of networked systems. We evaluate our proposal by employing the proposed architectures to a pervasive class of dynamic networks, i.e., wireless sensor network architectures as well as to a pervasive class of static networks, i.e., network-on-chip architectures. The ultimate goal of our research is to put forward the idea of building libraries of pre-proved rules for the efficient modelling, development, and analysis of networked systems. We take into account both qualitative and quantitative analysis of networks via varied formal tool support, using a theorem prover the Rodin platform and a statistical model checker the SMC-Uppaal.
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The capabilities and thus, design complexity of VLSI-based embedded systems have increased tremendously in recent years, riding the wave of Moore’s law. The time-to-market requirements are also shrinking, imposing challenges to the designers, which in turn, seek to adopt new design methods to increase their productivity. As an answer to these new pressures, modern day systems have moved towards on-chip multiprocessing technologies. New architectures have emerged in on-chip multiprocessing in order to utilize the tremendous advances of fabrication technology. Platform-based design is a possible solution in addressing these challenges. The principle behind the approach is to separate the functionality of an application from the organization and communication architecture of hardware platform at several levels of abstraction. The existing design methodologies pertaining to platform-based design approach don’t provide full automation at every level of the design processes, and sometimes, the co-design of platform-based systems lead to sub-optimal systems. In addition, the design productivity gap in multiprocessor systems remain a key challenge due to existing design methodologies. This thesis addresses the aforementioned challenges and discusses the creation of a development framework for a platform-based system design, in the context of the SegBus platform - a distributed communication architecture. This research aims to provide automated procedures for platform design and application mapping. Structural verification support is also featured thus ensuring correct-by-design platforms. The solution is based on a model-based process. Both the platform and the application are modeled using the Unified Modeling Language. This thesis develops a Domain Specific Language to support platform modeling based on a corresponding UML profile. Object Constraint Language constraints are used to support structurally correct platform construction. An emulator is thus introduced to allow as much as possible accurate performance estimation of the solution, at high abstraction levels. VHDL code is automatically generated, in the form of “snippets” to be employed in the arbiter modules of the platform, as required by the application. The resulting framework is applied in building an actual design solution for an MP3 stereo audio decoder application.
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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Mothers represent the natural caring. Natural caring is the object of caring science and of research interest because it establishes the central core of professional caring. In this study, we encounter patients who are mothers in need of care in a psychiatric context. Motherhood involves taking responsibility that extends beyond one's own life, because the child represents possibilities in a yet unknown future. Understanding and knowledge about the mothers' struggle in health and suffering are of crucial importance to enable clinical practice to make provisions for and adapt to the individual patient. The overall purpose of this dissertation is to illuminate how the innermost essence of caring emerges in health and suffering in patients who are mothers in psychiatric care. The purpose of the study in a clinical sense is to seek to understand and illuminate the patient's inner world in health and suffering in terms of contextual, existential, ontological and ethical dimensions. The dissertation is exploratory and descriptive in nature and encompasses induction, deduction and abduction as logics tools of reasoning. A theoretical model of natural caring and a universal theoretical model of the innermost essence of caring is developed as seen from the patient's world in a psychiatric context. The dissertation is anchored in human science's view of the human being and the world and in caring science's perspective. Caring science's view of the human being as a unity comprising body, soul and spirit is central in the study's concept of the patient. This multi-dimensional conception of the human being encompasses the dissertation's basic values and is decisive for choice of methodology. Hermeneutic epistemology guided the interpretation of the empirical data, the paradigmatic theses and assumptions. The dialectical movement in interpretation moves back and forth between empirical data, caring science theory and philosophical theory and reveals deeper insight into meaningful content in the clinical context. The interpretation process comprises four levels of abstraction: rational, contextual, existential and ontological. Hermeneutic philosophy guides the inductive and deductive approach to interpretation, as well as the movement between the clinical context and the caring science paradigm. In this encounter between the visible and invisible reality, the image of natural caring – motherliness emerged. The dissertation consists of four studies. The first study is a systematic review of nineteen research articles. The three other studies are hermeneutical interpretations based on text materials from open interviews. Fifteen participants were interviewed, all of whom are mothers of children between 0 and 18 years of age. All were outpatients in the psychiatric specialist health service. In the interpretation process, the mothers' struggle in health and suffering emerges as a struggle between the inner and outer world. Being a mother and patient in health and suffering in a psychiatric context means to struggle to be oneself, to create oneself, to live and realize one's good deeds as a mother and human being. To be oneself, to possess oneself as a mother is not only a question of tending, playing and learning in order to master a practical situation or to survive. It involves constituting a deep, inner desire to courageously create oneself so that the child is able to realize his or her potential in health and suffering. Motherliness manifests itself in caring as a call to ministering humanity and life. The voice of motherliness is understood as the voice of life—the eternal, inner call of love and freedom. The inner call craves fulfilment. Motherliness in natural caring does not retreat. Motherliness defines the Other as freedom and proceeds without regard for all other exterior requirements to realizing wellbeing. The inner essence of caring is attentive, aware and heeds the call of the heart. The innermost essence of caring is to be and to make oneself responsible for the Other. Responsibility cannot be relinquished; free choice consists in whether or not to follow the call. To renounce the inner call to responsibility is to deny oneself and one's dignity as a human being. The theoretical models provide clinical and systematic caring science with knowledge and understanding based on the natural caring spirit inherent in the human being. The study elucidates and strengthens the ontological basic assumptions about the human being as a unity of body, soul and spirit, the sanctity of the human being and the core of caring, ethos. The results of the dissertation will provide clinical practice with knowledge about the inner movements of the mothers' souls in relation to their responsibility as mothers and human beings. Being able to understand the basic conditions for responsibility is crucial for developing care that encompasses mother and child and the mutual relationship between them. This is basic knowledge for developing attitudes and actions that meet and provide for the needs of the patient as mother and as a whole, suffering human being.