5,627 research outputs found

    Applying the Open Source Development Model to Knowledge Work

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    This paper introduces a distinction between two different types of information goods in order to analyse the processes governing the review and integration of multi-authored contributions to information goods such as those produced through collaborations using the Internet as well as modular information goods such as open source software. It is argued that these distinctions are important because they suggest different organisational arrangements for producing such information goods. This method of analysing the nature of the information goods is employed to examine different organisational arrangements using the analogy of collaboration for traditional publication to identify actors and processes. The analysis of 'contributors' is extended from authorship to collectors and researchers. The paper examines a small survey of the governance procedures employed in projects that employ open source methods for collecting various types of information. We noted the prime role of the recruitment process in the relative success of the examples that we examined (ODP, Wikipedia, Nupedia, MathLearning, VRoma, and Web of Life). For these 'collection' efforts, the role of hierarchy in editing and review of project submissions appears to be important than in open source communities and may be an impediment to recruitment and project development. A number of directions for further research are identified.open source software, collaboration, hierarchies, trust, teams, co-operation

    The Open Source Way of Working: a New Paradigm for the Division of Labour in Software Development?

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    The interest the Open Source Software Development Model has recently raised amongst social scientists has resulted in an accumulation of relevant research concerned with explaining and describing the motivations of Open Source developers and the advantages the Open Source methodology has over traditional proprietary software development models. However, existing literature has often examined the Open Source phenomenon from an excessively abstract and idealised perspective of the common interests of open source developers, therefore neglecting the very important organisational and institutional aspects of communities of individuals that may, in fact, have diverse interests and motivations. It is the aim of this paper to begin remedying this shortcoming by analysing the sources of authority in Open Source projects and the hierarchical structures according to which this authority is organised and distributed inside them. In order to do so, a theoretical framework based on empirical evidence extracted from a variety of projects is built, its main concerns being the description and explanation of recruitment, enculturation, promotion and conflict resolution dynamics present in Open Source projects. The paper argues that 'distributed authority' is a principal means employed by such communities to increase stability, diminish the severity and scope of conflicts over technical direction, and ease the problems of assessing the quality of contributions. The paper also argues that distributed authority is principally derived from interpersonal interaction and the construction of trust between individuals drawn to the project by diverse interests that are mediated and moderated through participants' common interest in the project's successful outcome. The paper presents several conclusions concerning the governance of open source communities and priorities for future research.open source software, hierarchies, trust, teams, co-operation.

    Forecasting stock prices using Genetic Programming and Chance Discovery

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    In recent years the computers have shown to be a powerful tool in financial forecasting. Many machine learning techniques have been utilized to predict movements in financial markets. Machine learning classifiers involve extending the past experiences into the future. However the rareness of some events makes difficult to create a model that detect them. For example bubbles burst and crashes are rare cases, however their detection is crucial since they have a significant impact on the investment. One of the main problems for any machine learning classifier is to deal with unbalanced classes. Specifically Genetic Programming has limitation to deal with unbalanced environments. In a previous work we described the Repository Method, it is a technique that analyses decision trees produced by Genetic Programming to discover classification rules. The aim of that work was to forecast future opportunities in financial stock markets on situations where positive instances are rare. The objective is to extract and collect different rules that classify the positive cases. It lets model the rare instances in different ways, increasing the possibility of identifying similar cases in the future. The objective of the present work is to find out the factors that work in favour of Repository Method, for that purpose a series of experiments was performed.Forecasting, Chance discovery, Genetic programming, machine learning

    Glass in the submarine section of the HSDP2 drill core, Hilo, Hawaii

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    The Hawaii Scientific Drilling Project recovered ~3 km of basalt by coring into the flank of Mauna Kea volcano at Hilo, Hawaii. Rocks recovered from deeper than ~1 km were deposited below sea level and contain considerable fresh glass. We report electron microprobe analyses of 531 glasses from the submarine section of the core, providing a high-resolution record of petrogenesis over ca. 200 Kyr of shield building of a Hawaiian volcano. Nearly all the submarine glasses are tholeiitic. SiO2 contents span a significant range but are bimodally distributed, leading to the identification of low-SiO2 and high-SiO2 magma series that encompass most samples. The two groups are also generally distinguishable using other major and minor elements and certain isotopic and incompatible trace element ratios. On the basis of distributions of high- and low-SiO2 glasses, the submarine section of the core is divided into four zones. In zone 1 (1079–~1950 mbsl), most samples are degassed high-SiO2 hyaloclastites and massive lavas, but there are narrow intervals of low-SiO2 hyaloclastites. Zone 2 (~1950–2233 mbsl), a zone of degassed pillows and hyaloclastites, displays a continuous decrease in silica content from bottom to top. In zone 3 (2233–2481 mbsl), nearly all samples are undegassed low-SiO2 pillows. In zone 4 (2481–3098 mbsl), samples are mostly high-SiO2 undegassed pillows and degassed hyaloclastites. This zone also contains most of the intrusive units in the core, all of which are undegassed and most of which are low-SiO2. Phase equilibrium data suggest that parental magmas of the low-SiO2 suite could be produced by partial melting of fertile peridotite at 30–40 kbar. Although the high-SiO2 parents could have equilibrated with harzburgite at 15–20 kbar, they could have been produced neither simply by higher degrees of melting of the sources of the low-SiO2 parents nor by mixing of known dacitic melts of pyroxenite/eclogite with the low-SiO2 parents. Our hypothesis for the relationship between these magma types is that as the low-SiO2 magmas ascended from their sources, they interacted chemically and thermally with overlying peridotites, resulting in dissolution of orthopyroxene and clinopyroxene and precipitation of olivine, thereby generating high-SiO2 magmas. There are glasses with CaO, Al2O3, and SiO2 contents slightly elevated relative to most low-SiO2 samples; we suggest that these differences reflect involvement of pyroxene-rich lithologies in the petrogenesis of the CaO-Al2O3-enriched glasses. There is also a small group of low-SiO2 glasses distinguished by elevated K2O and CaO contents; the sources of these samples may have been enriched in slab-derived fluid/melts. Low-SiO2 glasses from the top of zone 3 (2233–2280 mbsl) are more alkaline, more fractionated, and incompatible-element-enriched relative to other glasses from zone 3. This excursion at the top of zone 3, which is abruptly overlain by more silica-rich tholeiitic magmas, is reminiscent of the end of Mauna Kea shield building higher in the core

    Multi-Agent Narrative Experience Management as Story Graph Pruning

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    In this thesis I describe a method where an experience manager chooses actions for non-player characters (NPCs) in intelligent interactive narratives through story graph representation and pruning. The space of all stories can be represented as a story graph where nodes are states and edges are actions. By shaping the domain as a story graph, experience manager decisions can be made by pruning edges. Starting with a full graph, I apply a set of pruning strategies that will allow the narrative to be finishable, NPCs to act believably, and the player to be responsible for how the story unfolds. By never pruning player actions, the experience manager can accommodate any player choice. This experience management technique was first implemented on a training simulation, where participants’ performance improved over repeated sessions. This technique was also employed on an adventure game where players generally found the NPCs’ behaviors to be more believable than the control

    Stratigraphy of the Hawai'i Scientific Drilling Project core (HSDP2): Anatomy of a Hawaiian shield volcano

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    The Hawai'i Scientific Drilling Project (HSDP2) successfully drilled ∌3.1 km into the island of Hawai'i. Drilling started on Mauna Loa volcano, drilling 247 m of subaerial lavas before encountering 832 m of subaerial Mauna Kea lavas, followed by 2019 m of submarine Mauna Kea volcanic and sedimentary units. The 2.85 km stratigraphic record of Mauna Kea volcano spans back to ∌650 ka. Mauna Kea subaerial lavas have high average olivine contents (13 vol.%) and low average vesicle abundances (10 vol.%). Most subaerial Mauna Kea flows are ‘a‘ā (∌63%), whereas the Mauna Loa section contains nearly equal amounts of pāhoehoe and ‘a‘ā (like its current surface). The submarine Mauna Kea section contains an upper, ∌900 m thick, hyaloclastite-rich section and a lower, ∌1100 m thick, pillow-lava-dominated section. These results support a model that Hawaiian volcanoes are built on a pedestal of pillow lavas capped by rapidly quenched, fragmented lava debris. The HSDP2 section is compared here to a 1.7 km deep hole (SOH1) on Kilauea's lower east rift zone. Differences in the sections reflect the proximity to source vents and the lower magma supply to Kilauea's rift zone. Both drill core sections are cut by intrusions, but the higher abundance of intrusions in SOH1 reflects its location within a rift zone, causing more extensive alteration in the SOH1 core. The HSDP2 site recovered a relatively unaltered core well suited for geochemical analyses of the single deepest and most complete borehole ever drilled through a Hawaiian or any other oceanic island volcano

    Assessing the Profitability of Guava Production in South Florida Under Risk and Uncertainty

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    This article discusses an assessment of the profitability of operating a 5-acre Thai guava orchard in South Florida. The assessment used simulation techniques to incorporate yield and price risks. The article also demonstrates the use of a stoplight chart, an approach Extension agents might adopt to aid clients\u27 decision making. The stoplight chart presents the results of the analysis, which indicate a 2% chance that the grower would experience a negative return/loss (red), a 21% chance that the return would be greater than 0butlessthan0 but less than 8,450 (yellow), and a 77% chance that the return would be greater than $8,450 (green)

    Preoperative Evaluation Prior to High-Risk Vascular Surgery

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    UNA PROPUESTA DEL MÉTODO DE ANÁLISIS DEL DESARROLLO ECONÓMICO LOCAL: EL CASO DE ALGUNOS TERRITORIOS LOCALES DEL ESTADO DE MÉXICO

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    El desarrollo econĂłmico local se ha considerado como una opciĂłn para fortalecer la armonĂ­a entre el espacio global y local, asĂ­ como un proceso que permite rescatar la importancia del espacio local para fomentar el desarrollo econĂłmico en un territorio. Para Marmolejo (2005), es un proceso consciente, basado en el aprovechamiento de los recursos, que conduce al crecimiento de la economĂ­a y al mejoramiento de las condiciones de vida de la poblaciĂłn. Con base en estos preceptos, el autor afirma que los nuevos procesos de desarrollo econĂłmico local buscan: 15 Generar mayor bienestar a la poblaciĂłn del municipio; estimular la participaciĂłn democrĂĄtica y activa de los ciudadanos. Promover el apoyo de los gobiernos locales a las actividades econĂłmicas en su territorio. Promover iniciativas locales para atraer inversiones, nuevas empresas y actividades econĂłmicas. Iniciar y/o ampliar la colaboraciĂłn entre el sector pĂșblico y el privado. Expandir y diversificar la base econĂłmica local; el crecimiento de la inversiĂłn, del empleo y de los ingresos. Fortalecer la competitividad de los sectores econĂłmicos instalados en el municipio.De manera tradicional, los paĂ­ses de AmĂ©rica Latina han establecido polĂ­ticas de desarrollo macroeconĂłmicas sin considerar el papel de los actores locales ni los objetivos de desarrollo sobre los que se basa una visiĂłn futura del paĂ­s. Sin embargo, algunos paĂ­ses del mundo han optado por aplicar una serie de polĂ­ticas sustentadas en el fortalecimiento del proceso de descentralizaciĂłn desde el punto de vista polĂ­tico-administrativo y territorial, tal es el caso de Europa, Asia y parte de AmĂ©rica Latina, donde se pueden identificar las caracterĂ­sticas de las polĂ­ticas pĂșblicas que, segĂșn Alburquerque (2004)
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