Applying the GWO Model to Relaxed Collaborative Systems

Building collaborative applications is still a challenging task. A collaborative application can be viewed as a class of distributed shared memory system. A distinctive property of these systems is their memory consistency model. In this paper, we argue that there is a relationship between different collaboration styles, on the one hand, and different memory consistency models, on the other. In particular, we propose a practical collaboration style, exemplified by a collaborative electronic organizer, that can be supported by the GWO memory consistency model, a rather relaxed model stricter only than local consistency. The advantage of the proposed style is that it reduces the amount of information that must be exchanged among the processors. Because there have been no propositions of the specific rules---i.e., the protocol---that the processors in a system must follow to implement the GWO model, we also propose a protocol that exactly matches the properties of the model

The Replica Consistency Problem in Data Grids

Fast and reliable data access is a crucial aspect in distributed computing and is often achieved using data replication techniques. In Grid architectures, data are replicated in many nodes of the Grid, and users usually access the "best" replica in terms of availability and network latency. When replicas are modifiable, a change made to one replica will break the consistency with the other replicas that, at that point, become stale. Replica synchronisation protocols exist and are applied in several distributed architectures, for example in distributed databases. Grid middleware solutions provide well established support for replicating data. Nevertheless, replicas are still considered read-only, and no support is provided to the user for updating a replica while maintaining the consistency with the other replicas. In this thesis, done in collaboration with the Italian National Institute of Nuclear Physics (INFN) and the European Organisation for Nuclear Research (CERN), we study the replica consistency problem in Grid computing and propose a service, called CONStanza, that is able to synchronise both files and heterogeneous (different vendors) databases in a Grid environment. We analyse and implement a specific use case that arises in high energy Physics, where conditions databases are replicated using databases of different makes. We provide detailed performance results, and show how CONStanza can be used together with Oracle Streams to provide multitier replication of conditions databases using Oracle and MySQL databases

Nuclear versus Coal plus CCS: A Comparison of Two Competitive Base-load Climate Control Options

In this paper we analyze the relative importance and mutual behavior of two competing base-load electricity generation options that each are capable of contributing significantly to the abatement of global CO2 emissions: nuclear energy and coal-based power production complemented with CO2 capture and storage (CCS). We also investigate how, in scenarios from an integrated assessment model that simulates the economics of a climate-constrained world, the prospects for nuclear energy would change if exogenous limitations on the spread of nuclear technology were relaxed. Using the climate change economics model WITCH we find that until 2050 the resulting growth rates of nuclear electricity generation capacity become comparable to historical rates observed during the 1980s. Given that nuclear energy continues to face serious challenges and contention, we inspect how extensive the improvements of coal-based power equipped with CCS technology would need to be if our model is to significantly scale down the construction of new nuclear power plants.Economic Competition, Electricity Sector, Nuclear Power, Coal Power, CCS, Renewables, Climate Policy

Simulatore per un servizio di consistenza su architetture Grid

Integrazione di CONStanza e OptorSim al fine di ottenere un simulatore per il servizio di consistenza per la replicazione dei dati

The relationship between students and teachers' use of language learning strategies at univercity level

Tesis (Profesor de Inglés para la Enseñanza Básica y Media y al grado académico de Licenciado en Educación)This case study aims to explore the field of LLS in Chile, specifically in the English language learning area. The purposes of this research are: to identify which LLS were fostered by the teacher through class tasks, discover which LLS were used by the students and know if there is a relation between fostered LLS by the teacher and used LLS by the students. The participants who collaborated with this research were a group of students from the second year of a TEFL program in a private Chilean university, and their teacher from the grammar module of an English Language course. A quantitative approach was chosen because it provided hard data, that is, results showed frequency of fostering and use of LLS, which allowed the investigators to objectively compare the results. In order to obtain the results, the employed instruments were: an adapted version of the Strategy Inventory for Language Learning (SILL) created by Rebecca Oxford (1990), which was applied to the teacher by observing him during three lessons, and a questionnaire created in function of the SILL - which was answered by the students. The findings evidenced the existence of a relation between some of the LLS fostered by the teacher and the ones used by the students, these were cognitive and metacognitive strategies. However, in other categories of LLS, such as in compensation strategies, there was not any relation whatsoever. Also, not all strategies were observed in both groups. The last step of the investigation showed that LLS are fostered and used with different priorities, its results revealed that some LLS were the 30% of the total number of categories while others obtained 0%.El presente estudio de caso aspiró a explorar el campo de las estrategias de aprendizaje de idiomas en Chile, específicamente referido al área del aprendizaje de inglés. Parte del propósito fue identificar cuáles estrategias de aprendizaje de idiomas eran promovidas por el profesor a través de tareas realizadas en clases. También, se intentó descubrir cuáles estrategias eran usadas por los estudiantes. Finalmente, se pretendió saber si existía una relación entre las estrategias promovidas por el profesor y aquellas usadas por los estudiantes. Los participantes que colaboraron con esta investigación fueron: un grupo de estudiantes cursando segundo año de pedagogía en inglés en una universidad privada en Chile, y su profesor del módulo de gramática correspondiente a un ramo de inglés (compuesto por más módulos como fonética y uso de inglés en general). El enfoque escogido fue cuantitativo, ya que proveyó datos duros, los resultados arrojaron la frecuencia de promoción y uso de las estrategias de aprendizaje del idioma. Ésto permitió comparar los resultados objetivamente. Los instrumentos empleados fueron: una adaptación del SILL (Strategy Inventory for Language Learning) que consistía en una lista de estrategias creada por Rebecca Oxford en 1990 cuyo propósito era observar la promoción de estrategias, y un cuestionario que fue respondido por los alumnos. Los resultados reflejaron la existencia de una relación entre algunas estrategias tales como cognitivas y metacognitivas. Sin embargo, en otras categorías, como en las estrategias de compensación, no se encontró ninguna relación. Además, no todas las estrategias fueron observadas en ambos grupos. El último paso de la investigación mostró que las estrategias son promovidas y usadas con diferentes prioridades. Los resultados arrojaron que la promoción y uso de algunas estrategias obtuvieron 30% entre el número total de estrategias, mientras que otras obtuvieron 0% de promoción. Esta investigación se podría extender al explorar el uso de estrategias específicas. También podría ser aplicado a contextos con diferentes realidades a través del país

Does Social Capital Create Trust? Evidence from a Community of Entrepreneurs

Which kind of social capital fosters the diffusion of development-oriented trust? This paper carries out an empirical investigation into the causal relationships connecting four types of social capital (i.e. bonding, bridging, linking, and corporate), and different forms of trust (knowledge-based trust, social trust, trust towards public services and political institutions), in a community of entrepreneurs located in the Italian industrial district of the Tuscia. Our results suggest that the main factors fostering the diffusion of social trust among entrepreneurs are the perception that the local community is a safe place, and the establishment of corporate ties through professional associations. Trust in people is positively and significantly correlated also to higher levels of satisfaction and confidence in public services. Participation in voluntary organizations does not appear to increase trust in people. Rather, we find evidence of the other way round: interpersonal trust seems to encourage civic engagement.Trust, Social capital, Safety, Professional associations, Entrepreneurship, Corporate ties, Group and Interpersonal Processes, Social Perception and Cognition

Filogenia y biogeografía del Clado Antillattus (Araneae: Salticidae: Euophryini)

The Euophryini tribe is currently one of the most diverse groups of salticidae. Within this group, the neotropic is represented by 11 clades, included the Antillattus clade (Antillattus 13 spp, Truncattus 5 spp, Petemathis 5 spp, possibly Allodecta 1 spp and Caribatus 1 spp). To clarify the phylogeny and biogeography of the Antillattus clade, we amplified and sequenced three genes (nuclear: 28S rDNA; mitochondrial: 16S, COI) corresponding to species belonging to the study group and outgroups (68 terminals). In addition, a total of 125 morphological characters were used, which in combination with the molecular evidence, helped to clarify the relationships between genera and species. Additionally, the GAARlandia hypothesis and the non-GAARlandia hypothesis are tested as possible routes of colonization and diversification of the Antillattus clade. The combined working hypothesis (DNA + morphology) supports the monophyly of the Antillattus clade. The results indicate that the genus Antillattus sensus Zhang and Maddison (2015), is not monophyletic, and it is divided into the genus Pensacolatus, Antillattus and Bryanattus gen. nov.. The results also supported the transferences of species to the genera Truncattus, Bryanattus gen. nov., Cobanus, Compsodecta, and the description of the genus Paracobanus gen. nov.. The detailed review provides new limits of genera and species, 19 comb. nov., 2 gen. nov., 11 sp. nov.. Finally, the results also suggest that the radiation of the group occurred in the last period of GAARlandia and that diversification within the Greate Antilles is the result of vicariance and founder-event. Additionally, evidence suggest that Hispaniola played a role as a point of dispersion to other Antillean islands.La tribu Euophryini resulta en la actualidad, una de las más diversas dentro de la familia salticidae. Dentro de este grupo, los representantes neotropicales conforman 11 clados, de los cuales, el clado Antillattus (Antillattus 13 spp, Truncattus 5 spp, Petemathis 5 spp, posiblemente Allodecta 1 spp, Caribatus 1 spp) resulta exclusivo del Caribe insular. Para aclarar la filogenia y biogeografía del clado Antillattus, amplificamos y secuenciamos tres genes (nuclear: 28S rDNA; mitocondrial: 16S, COI) correspondientes a especies pertenecientes al grupo de estudio y a grupos hermanos (68 terminales en total) dentro de gran parte del Caribe biogeográfico. Además, se utilizó un total de 125 caracteres morfológicos, que en combinación con la evidencia molecular, ayudó a aclarar las relaciones entre los géneros y especies. Se estudió en mayor detalle los caracteres morfológicos de los géneros y especies del clado Antillattus así como de sus grupos relacionados con el objetivo de profundizar en la comprensión de filogenética desde una panorámica morfológica. Adicionalmente, para comprender el origen y el momento de la colonización del grupo, se pone a prueba la hipótesis de GAARlandia y la hipotesis no-GAARlandia como posibles vías de colonización y diversificación del cladoAntillattus en las Antillas Mayores. La hipotesis combinada (ADN+morfología) de trabajo, apoya la monofilia del clado Antillattus. Los resultados indican que el género Antillattus sensus Zhang y Maddison (2015), no es monofilético, y para el presente estudio se divide en los géneros Pensacolatus, Antillattus y Bryanattus gen. nov.. La filogenia combinada de datos morfológicos y moleculares, también apoyó la transferencia de especies a los géneros Truncattus, Bryanattus, Cobanus, Compsodecta y la descripción del género Paracobanus gen. nov.. La revisión detallada proporciona nuevos limites de géneros y especies, 19 comb. nov., 2 gen. nov., 11 sp. nov.. Finalmente, los resultados también sugieren que la radiación del grupo tuvo lugar en el último periodo de GAARlandia y que la diversificación dentro del Caribe insular, es el resultado de vicarianza y eventos fundadores. Adicionalmente, se encontró evidencia que sugiere que La Española jugó un papel como punto de distribución hacia Cuba y Puerto Rico.Doctorad

Countering Groupthink: The Inner-Circle of Influence

As noted by research journalists, Hart, Stern & Sundelius (1997), foreign policy decisions "...are shaped in relatively small groups and informal face-to-face interaction" (p 4). This study explores the influence of small groups on the effectiveness of decision-making techniques and examines how to counter the new forms of groupthink such as an inner-circle of influence.This project utilizes an experimental design study to test the relative efficiency of two decision-making models in a pre-scripted scenario in countering this new inner-circle form of groupthink. Using a cross-over research design, participants responded to each scenario with random assignment into one of two decision-making models: the Delphi model and an iterative feedback technique referred to in this paper as the Continuous Group Problem Solving (CGPS) model. After completing two decision-making scenarios, participants identified the most effective decision-making model overall and potential for this method to counter dominance by an inner-circle of influence.The results from this study are significant since the findings reconceptualize the term groupthink as a simpler term implying inner-circle influence that preempts thorough decision-making. The findings also provide insight for future application in countering the deleterious control of an "inner-circle." These exploratory research results are ripe for replication in large corporate or Government organizations, The desire to have a voice in the decision process and to overcome inner-circle influence will be of value to those conducting future research

Forward Together: Building a Field that Works for Families

The coronavirus pandemic revealed the necessity, the complexity, and the tremendous value of building strong ties between schools and families. To ensure continuity of learning, schools were forced to rely heavily on families and caregivers to support learning in the home. But the conversation around family engagement is not new. The value of family involvement in education has been clear for decades, with strong evidence establishing this engagement as a critical driver of student academic and socioemotional outcomes. Building on this robust research base, the Carnegie Corporation of New York (CCNY) in 2016 began to explore a strategy of building the home-to-school connection. CCNY partnered with EY-Parthenon to study the role of philanthropy in bringing strong family engagement practices to schools and districts. EY-Parthenon found that funders actively supported family engagement, but the field lacked clear definitions of what constituted engagement and needed to create infrastructure to allow for shared learning and field building

Uses of National Accounts; History, International Standardization and Applications in the Netherlands

The national accounts is commonly known by its key-aggregates (e.g. GDP and saving) and their role in public debate and decision-making. However, the national accounts plays many different roles for many different uses. This paper provides an overview of the development of these roles and uses since the seventeenth century. Three periods are distinguished: the early estimates (1660-1930), revolutionary decades (1930-1950) and the era of the international guidelines (1950-present). The paper discusses these roles and uses also much more in detail for one country: the Netherlands, a country which played an important role in modern national accounting and where expert data users, like the CPB, SCP and the Dutch central bank, have developed several interesting applications of the national accounts.Uses of the national accounts, history of national accounting, history of taxation, economic growth, Dutch national accounts, relevance and reliability of the national accounts, Petty, King, Vauban, Quesnay, Keynes, Clark, Kuznets, Leontief, Tinbergen, Hicks, van Cleeff, Stone, Meade, guidelines on national accounting, European unification, macro-economic modeling and forecasting, CPB, SCP, Dutch central bank, fiscal policy, productivity analysis, performance management, national accounts and welfare, measurement in economics