957 resultados para explicit formulas


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By a standard application of Jones's method associated with the Wiener-Hopf technique an explicit solution is obtained for the temperature distribution inside a cylindrical rod with an insulated inner core when the rod is allowed to enter into a fluid of large extent with a uniform speed, and a simple integral expression is derived for the value of the sputtering temperature of the rod at the points of entry. Numerical results under certain special circumstances are also obtained and presented in the form of a table.

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Approximate closed-form solutions of the non-linear relative equations of motion of an interceptor pursuing a target under the realistic true proportional navigation (RTPN) guidance law are derived using the Adomian decomposition method in this article. In the literature, no study has been reported on derivation of explicit time-series solutions in closed form of the nonlinear dynamic engagement equations under the RTPN guidance. The Adomian method provides an analytical approximation, requiring no linearization or direct integration of the non-linear terms. The complete derivation of the Adomian polynomials for the analysis of the dynamics of engagement under RTPN guidance is presented for deterministic ideal case, and non-ideal dynamics in the loop that comprises autopilot and actuator dynamics and target manoeuvre, as well as, for a stochastic case. Numerical results illustrate the applicability of the method.

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The thesis is about Finnish freestyle-rap, a modern form of oral poetry producing improvised rap lyrics at the moment of performance. The research material consists of interviews with seven freestyle experts and a DVD from Finnish Rap Championships 2005 containing freestyle-rap. The thesis has three goals: describing the different variations or subgenres of freestyle, outlining the esthetics and register of freestyle, and examining the composition of freestyle. The research material acts a central role in the thesis but the theoretical framework is also wide: cornerstones are John Miles Foley's register analysis, oral formulaic theory and William Levelt's psycholinguistic theory on planning of speech. Freestyle is divided into three partially overlapping genres with slight variation in conventions. The genres are freestyle battle, cypher, and live freestyle. Freestyle's esthetics are composed of certain qualities and preferences: the rhyme is a syllabically repeating vocal rhyme. The rapping must be synchronised with the background rhythm and the rhyme comes in the end of the line. The lyrics must be somehow anchored to the surroundings and the moment of performance. The style of rapping, ie. flow, has to be personal one way or the other. Individual formulas are used to some extent in freestyle compostition. When planning the lines, all other content is subordinate to the rhyme, whose phonetic processing is the primary act in the planning of freestyle. This discovery sets Levelt's theory open to doubt.

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In this paper we consider the third-moment structure of a class of time series models. It is often argued that the marginal distribution of financial time series such as returns is skewed. Therefore it is of importance to know what properties a model should possess if it is to accommodate unconditional skewness. We consider modeling the unconditional mean and variance using models that respond nonlinearly or asymmetrically to shocks. We investigate the implications of these models on the third-moment structure of the marginal distribution as well as conditions under which the unconditional distribution exhibits skewness and nonzero third-order autocovariance structure. In this respect, an asymmetric or nonlinear specification of the conditional mean is found to be of greater importance than the properties of the conditional variance. Several examples are discussed and, whenever possible, explicit analytical expressions provided for all third-order moments and cross-moments. Finally, we introduce a new tool, the shock impact curve, for investigating the impact of shocks on the conditional mean squared error of return series.

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Maila Pylkkönen (1931 1986) was one of the most important modernist poets in Finland and a central figure in developing the dramatic monologue in Finnish literature. The study examines Pylkkönen s poetic work Arvo. Vanhaäiti puhuu runonsa (Value. An old woman speaks her poem, 1959) as an example of the dramatic monologue, approaching it from three perspectives: its generic features and background, and the poetic framework to which it connects in the context of Pylkkönen s poetry. In addition to methods of literary scholarship, the poetic analysis benefits from a linguistic approach. The study shows that the dramatic monologue genre drives Pylkkönen s first work, Klassilliset tunteet (Classical feelings, 1957), in a context of finding poetic identity, characterised by the expression to be the words of a living creature . The study demonstrates that important generic features of the dramatic monologue, namely, a poem representing a speech-event and a hierarchical structure, are also Arvo s most significant generic features. Arvo s poems as speech-events are examined for their internal progressive, pragmatic unity constructed through single line units; for their function as narratives dealing with the life story of an old woman, Arvo s speaker; and from the perspective of the communication between the old woman and the poems other characters. Arvo s speech-events can also be seen as semantic shifts from one poem to another: the poems construct semantic stages representing different phases of the old woman s life. The study demonstrates that analysis of Arvo s hierarchical structure, that is, the relationship between the speaker and the rhetorical levels, reveals the work s structural and ideological wholeness by focusing on the old woman s emotions: longing, loneliness and alienation from the world. In other words, the contradictions between the explicit level of the speaker and an implied rhetorical level open up the tragedy of an old woman s daily life. Study of Arvo s hierarchical structure also highlights the special position of the reader in the framework of a dramatic monologue. The elements of a dramatic present in which the old woman s emotions are conveyed, an italicized opening poem, and the work s title Value invite the reader to consider Arvo as a structural and ideological whole. The function of Arvo s hierarchical structure is to ask the reader to recognise the hopelessness of the old woman s situation, understand it, and even identify with it.

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This paper is concerned the calculation of flame structure of one-dimensional laminar premixed flames using the technique of operator-splitting. The technique utilizes an explicit method of solution with one step Euler for chemistry and a novel probabilistic scheme for diffusion. The relationship between diffusion phenomenon and Gauss-Markoff process is exploited to obtain an unconditionally stable explicit difference scheme for diffusion. The method has been applied to (a) a model problem, (b) hydrazine decomposition, (c) a hydrogen-oxygen system with 28 reactions with constant Dρ 2 approximation, and (d) a hydrogen-oxygen system (28 reactions) with trace diffusion approximation. Certain interesting aspects of behaviour of the solution with non-unity Lewis number are brought out in the case of hydrazine flame. The results of computation in the most complex case are shown to compare very favourably with those of Warnatz, both in terms of accuracy of results as well as computational time, thus showing that explicit methods can be effective in flame computations. Also computations using the Gear-Hindmarsh for chemistry and the present approach for diffusion have been carried out and comparison of the two methods is presented.

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The effectiveness of any trapping system is highly dependent on the ability to accurately identify the specimens collected. For many fruit fly species, accurate identification (= diagnostics) using morphological or molecular techniques is relatively straightforward and poses few technical challenges. However, nearly all genera of pest tephritids also contain groups of species where single, stand-alone tools are not sufficient for accurate identification: such groups include the Bactrocera dorsalis complex, the Anastrepha fraterculus complex and the Ceratitis FAR complex. Misidentification of high-impact species from such groups can have dramatic consequences and negate the benefits of an otherwise effective trapping program. To help prevent such problems, this chapter defines what is meant by a species complex and describes in detail how the correct identification of species within a complex requires the use of an integrative taxonomic approach. Integrative taxonomy uses multiple, independent lines of evidence to delimit species boundaries, and the underpinnings of this approach from both the theoretical speciation literature and the systematics/taxonomy literature are described. The strength of the integrative approach lies in the explicit testing of hypotheses and the use of multiple, independent species delimitation tools. A case is made for a core set of species delimitation tools (pre- and post-zygotic compatibility tests, multi-locus phylogenetic analysis, chemoecological studies, and morphometric and geometric morphometric analyses) to be adopted as standards by tephritologists aiming to resolve economically important species complexes. In discussing the integrative approach, emphasis is placed on the subtle but important differences between integrative and iterative taxonomy. The chapter finishes with a case study that illustrates how iterative taxonomy applied to the B. dorsalis species complex led to incorrect taxonomic conclusions, which has had major implications for quarantine, trade, and horticultural pest management. In contrast, an integrative approach to the problem has resolved species limits in this taxonomically difficult group, meaning that robust diagnostics are now available.

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This research deals with direct speech quotations in magazine articles through two questions: As my major research question, I study the functions of speech quotations based on a data consisting of six literary-journalistic magazine articles. My minor research question builds on the fact that there is no absolute relation between the sound waves of the spoken language and the graphemes of the written one. Hence, I study the general thoughts on how utterances should be arranged in the written form based on a large review of literature and textbooks on journalistic writing as well as interviews I have made with magazine writers and editors, and the Council of Mass Media in Finland. To support my main research questions, I also examine the reference system of the Finnish language, define the aspects of the literary-journalistic article and study vernacular cues in written speech quotations. FUNCTIONS OF QUOTATIONS. I demonstrate the results of my analysis with a six-pointed apparatus. It is a continuum which extends from the structural level of text, all the way through the explicit functions, to the implicit functions of the quotation. The explicit functions deal with the question of what is the content, whereas the implicit ones base mainly on the question how the content is presented. 1. The speech quotation is an distinctive element in the structure of the magazine article. Thereby it creates a rhythm for the text, such as episodes, paragraphs and clauses. 2. All stories are told through a plot, and in magazine articles, the speech quotations are one of the narrative elements that propel the plot forward. 3. The speech quotations create and intensify the location written in the story. This location can be a physical one but also a social one, in which case it describes the atmosphere and mood in the physical environment and of the story characters. 4. The quotations enhance the plausibility of the facts and assumptions presented in the article, and moreover, when a text is placed between quotation marks, the reader can be assured that the text has been reproduced in the authentic verbatim way. 5. Speech quotations tell about the speaker's unique way of using language and the first-hand experiences of the person quoted. 6. The sixth function of speech quotations is probably the most essential one: the quotations characterize the quoted speaker. In other words, in addition to the propositional content of the utterance, the way in which it has been said transmits a lot of the speaker's character (e.g. nature, generation, behaviour, education, attitudes etc.). It is important to notice, that these six functions of my speech quotation apparatus do not exlude one another. It means that every speech quotation basically includes all of the functions discussed above. However, in practice one or more of them have a principal role, while the others play a subsidiary role. HOW TO MAKE QUOTATIONS? It is not suprising that the field of journalism (textbooks, literature and interviews) holds heterogeneous and unestablished thoughts on how the spoken language should be arranged in written quotations, which is my minor research question. However, the most frequent and distinctive aspects can be depicted in a couple of words: serve the reader and respect the target person. Very common advice on how to arrange the quotations is − firstly, to delete such vernacular cues (e.g. repetitions and ”expletives”) that are common in spoken communication, but purposeless in the written language. − secondly, to complete the phonetic word forms of the spoken language into a more reader-friendly form (esim. punanen → punainen, 'red'), and − thirdly, to enhance the independence of clauses from the (authentic) context and to toughen reciprocal links between them. According to the knowledge of the journalistic field, utterances recorded in different points in time of an interview or a data-collecting session can be transferred as consecutive quotations or even merged together. However, if there is any temporal-spatial location written in the story, the dialogue of the story characters should also be situated in an authentic context – chronologically in the right place in the continuum of the events. To summarize, the way in which the utterances should be arranged into written speech quotations is always situationally-specific − and it is strongly based on the author's discretion.

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Discarding in commercially exploited fisheries has received considerable attention in the last decade, though only more recently in Australia. The Reef Line fishery (RLF) of the Great Barrier Reef (GBR) in Australia is a large-scale multi-sector, multi-species, highly regulated hook and line fishery with the potential for high levels of discarding. We used a range of data sources to estimate discard rates and discard quantities for the two main target groups of the RLF, the coral trout, Plectropomus spp, and the red throat emperor, Lethrinus miniatus, and investigated possible effects on discarding of recent changes in management of the fishery. Fleet-wide estimates of total annual quantities discarded from 1989 to 2003 were 292-622 t and 33-95 t for coral trout and red throat emperor, respectively. Hypothetical scenarios of high-grading after the introduction of a total allowable commercial catch for coral trout resulted in increases in discard quantities up to 3895 t, while no high-grading still meant 421 t were discarded. Increasing the minimum size limit of red throat emperor from 35 to 38 cm also increased discards to an estimated 103 t. We provide spatially and temporally explicit estimates of discarding for the two most important species in the GBR RLF of Australia to demonstrate the importance of accounting for regional variation in quantification of discarding. Effects of management changes on discarding are also highlighted. This study provides a template for exploring discarding levels for other species in the RLF and elsewhere.

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Computer modelling promises to be an important tool for analysing and predicting interactions between trees within mixed species forest plantations. This study explored the use of an individual-based mechanistic model as a predictive tool for designing mixed species plantations of Australian tropical trees. The `spatially explicit individually based-forest simulator' (SeXI-FS) modelling system was used to describe the spatial interaction of individual tree crowns within a binary mixed-species experiment. The three-dimensional model was developed and verified with field data from three forest tree species grown in tropical Australia. The model predicted the interactions within monocultures and binary mixtures of Flindersia brayleyana, Eucalyptus pellita and Elaeocarpus grandis, accounting for an average of 42% of the growth variation exhibited by species in different treatments. The model requires only structural dimensions and shade tolerance as species parameters. By modelling interactions in existing tree mixtures, the model predicted both increases and reductions in the growth of mixtures (up to +/-50% of stem volume at 7 years) compared to monocultures. This modelling approach may be useful for designing mixed tree plantations.

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Design embraces several disciplines dedicated to the production of artifacts and services. These disciplines are quite independent and only recently has psychological interest focused on them. Nowadays, the psychological theories of design, also called design cognition literature, describe the design process from the information processing viewpoint. These models co-exist with the normative standards of how designs should be crafted. In many places there are concrete discrepancies between these two in a way that resembles the differences between the actual and ideal decision-making. This study aimed to explore the possible difference related to problem decomposition. Decomposition is a standard component of human problem-solving models and is also included in the normative models of design. The idea of decomposition is to focus on a single aspect of the problem at a time. Despite its significance, the nature of decomposition in conceptual design is poorly understood and has only been preliminary investigated. This study addressed the status of decomposition in conceptual design of products using protocol analysis. Previous empirical investigations have argued that there are implicit and explicit decomposition, but have not provided a theoretical basis for these two. Therefore, the current research began by reviewing the problem solving and design literature and then composing a cognitive model of the solution search of conceptual design. The result is a synthetic view which describes recognition and decomposition as the basic schemata for conceptual design. A psychological experiment was conducted to explore decomposition. In the test, sixteen (N=16) senior students of mechanical engineering created concepts for two alternative tasks. The concurrent think-aloud method and protocol analysis were used to study decomposition. The results showed that despite the emphasis on decomposition in the formal education, only few designers (N=3) used decomposition explicitly and spontaneously in the presented tasks, although the designers in general applied a top-down control strategy. Instead, inferring from the use of structured strategies, the designers always relied on implicit decomposition. These results confirm the initial observations found in the literature, but they also suggest that decomposition should be investigated further. In the future, the benefits and possibilities of explicit decomposition should be considered along with the cognitive mechanisms behind decomposition. After that, the current results could be reinterpreted.

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[Excerpt] This book is about restoring the upward mobility of U.S. workers. Specifically it is about the one workforce-development strategy that is currently aimed at exactly that goal – the strategy of creating (or re-creating) not just jobs but also career ladders. Career-ladder strategies aim to devise explicit pathways of occupational advancement.

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We demonstrate a chain length dependent crossover in the structural properties of linear hydrocarbon (n-alkane) chains using detailed atomistic simulations in explicit water. We identify a number of exotic structures of the polymer chain through energy minimization of representative snapshots collected from molecular dynamics trajectory. While the collapsed state is ring-like (circular) for small chains (CnH2n+2; n <= 20) and spherical for very long ones (n = 100), we find the emergence of ordered helical structures at intermediate lengths (n similar to 40). We find different types of disordered helices and toroid-like structures at n = 60. We also report a sharp transition in the stability of the collapsed state as a function of the chain length through relevant free energy calculations. While the collapsed state is only marginally metastable for C20H42, a clear bistable free energy surface emerges only when the chain is about 30 monomers long. For n = 30, the polymer exhibits an intermittent oscillation between the collapsed and the coil structures, characteristic of two stable states separated by a small barrier.

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For the quasi-static, Rayleigh-fading multiple-input multiple-output (MIMO) channel with n(t) transmit and n(r) receive antennas, Zheng and Tse showed that there exists a fundamental tradeoff between diversity and spatial-multiplexing gains, referred to as the diversity-multiplexing gain (D-MG) tradeoff. Subsequently, El Gamal, Caire, and Damen considered signaling across the same channel using an L-round automatic retransmission request (ARQ) protocol that assumes the presence of a noiseless feedback channel capable of conveying one bit of information per use of the feedback channel. They showed that given a fixed number L of ARQ rounds and no power control, there is a tradeoff between diversity and multiplexing gains, termed the diversity-multiplexing-delay (DMD) tradeoff. This tradeoff indicates that the diversity gain under the ARQ scheme for a particular information rate is considerably larger than that obtainable in the absence of feedback. In this paper, a set of sufficient conditions under which a space-time (ST) code will achieve the DMD tradeoff is presented. This is followed by two classes of explicit constructions of ST codes which meet these conditions. Constructions belonging to the first class achieve minimum delay and apply to a broad class of fading channels whenever n(r) >= n(t) and either L/n(t) or n(t)kslashL. The second class of constructions do not achieve minimum delay, but do achieve the DMD tradeoff of the fading channel for all statistical descriptions of the channel and for all values of the parameters n(r,) n(t,) L.

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Miconia calvescens (Melastomataceae) is a serious invader in the tropical Pacific, including the Hawaiian and Tahitian Islands, and currently poses a major threat to native biodiversity in the Wet Tropics of Australia. The species is fleshy-fruited, small-seeded and shade tolerant, and thus has the potential to be dispersed widely and recruit in relatively intact rainforest habitats, displacing native species. Understanding and predicting the rate of spread is critical for the design and implementation of effective management actions. We used an individual-based model incorporating a dispersal function derived from dispersal curves for similar berry-fruited native species, and life-history parameters of fecundity and mortality to predict the spatial structure of a Miconia population after a 30 year time period. We compared the modelled population spatial structure to that of an actual infestation in the rainforests of north Queensland. Our goal was to assess how well the model predicts actual dispersion and to identify potential barriers and conduits to seed movement and seedling establishment. The model overpredicts overall population size and the spatial extent of the actual infestation, predicting individuals to occur at a maximum 1,750 m from the source compared with the maximum distance of any detected individual in the actual infestation of 1,191 m. We identify several characteristic features of managed invasive populations that make comparisons between modelled outcomes and actual infestations difficult. Our results suggest that the model’s ability to predict both spatial structure and spread of the population will be improved by incorporating a spatially explicit element, with dispersal and recruitment probabilities that reflect the relative suitability of different parts of the landscape for these processes.