333 resultados para TCP connection


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The social media statistics of South Africa reveal an exponential increase in the use of social media. Libraries, as part of a community, cannot ignore this! Social media provide libraries instant and direct connection with their members regardless their geographical location. This paper explores social media use in libraries. The establishment of social media for the SABC Media Libraries is discussed to demonstrate a practical implementation of social media in libraries and archives. Tips and resources, with specific mention to Twitter and Facebook, as well as social media etiquette and social media policy guidelines are supplied. The literature of published articles and Infographic show the changing role of librarians in the social media era and the need for librarians to keep learning and update their skills to accommodate users’ needs. The focus should now be on how well we do social media for the library, not on whether we should do it or not! Keywords: Social Media, Libraries, Web 2.0, Librarians, Archives, SABC, South Africa.

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Organizations are increasingly seeking stakeholder support through engagement to demonstrate their corporate social responsibility (CSR) credentials. These credentials are in turn used to support claims of legitimacy for organizational operations. This paper uses a process model of antecedents, implementation, and consequences to study the connection between engagement and CSR. CSR reports show organizations perceive engagement in CSR as both communication and activities between organizations and their stakeholders; and as a second, meta-level of communication about that engagement with stakeholders beyond those directly involved, thereby broadening the scope of organizational claims to legitimacy. Understanding what engagement is and how and why it is carried out in CSR provides a framework for understanding engagement in public relations.

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The social media statistics of South Africa reveal an exponential increase in the use of social media. Libraries, as part of a community, cannot ignore this! Social media provide libraries instant and direct connection with their members regardless their geographical location. This paper explores social media use in libraries. The establishment of social media for the SABC Media Libraries is discussed to demonstrate a practical implementation of social media in libraries and archives. Tips and resources, with specific mention to Twitter and Facebook, as well as social media etiquette and social media policy guidelines are supplied. The literature of published articles and Infographic show the changing role of librarians in the social media era and the need for librarians to keep learning and update their skills to accommodate users’ needs. The focus should now be on how well we do social media for the library, not on whether we should do it or not!

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Battery-supercapacitor hybrid energy storage systems are becoming popular in the renewable energy sector due to their improved power and energy performances. These hybrid systems require separate dc-dc converters, or at least one dc-dc converter for the supercapacitor bank, to connect them to the dc-link of the grid interfacing inverter. These additional dc-dc converters increase power losses, complexity and cost. Therefore, possibility of their direct connection is investigated in this paper. The inverter system used in this study is formed by cascading two 3-level inverters, named as the “main inverter” and the “auxiliary inverter”, through a coupling transformer. In the test system the main inverter is connected with the rectified output of a wind generator while the auxiliary inverter is directly attached to a battery and a supercapacitor bank. The major issues with this approach are the dynamic changes in dc-link voltages and inevitable imbalances in the auxiliary inverter voltages, which results in unevenly distributed space vectors. A modified SVM technique is proposed to solve this issue. A PWM based time sharing method is proposed for power sharing between the battery and the supercapacitor. Simulation results are presented to verify the efficacy of the proposed modulation and control techniques.

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The human right to water has recently been recognised by both the United Nations General Assembly and the Human Rights Council. As the mining industry interacts with water on multiple levels, it is important that these interactions respect the human right to water. Currently, a disconnect exists between mine site water management practices and the recognition of water from a human rights perspective. The Minerals Council of Australia (MCA) Water Accounting Framework (WAF) has previously been used to strengthen the connection between water management and human rights. This article extends this connection through the use of a Social Water Assessment Protocol (SWAP). The SWAP is scoping tool consisting of a set of questions classified into taxonomic themes under leading topics with suggested sources of data that enable mine sites to better understand the local water context in which they operate. Three of the themes contained in the SWAP – gender, Indigenous peoples and health – are discussed to demonstrate how the protocol may be useful in assisting mining companies to consider their impacts on the human right to water.

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An offshore wind turbine usually has the grid step-up transformer integrated in the nacelle. This increases mechanical loading of the tower. In that context, a transformer-less, high voltage, highly-reliable and compact converter system for nacelle installation would be an attractive solution for large offshore wind turbines. This paper, therefore, presents a transformer-less grid integration topology for PMSG based large wind turbine generator systems using modular matrix converters. Each matrix converter module is fed from three generator coils of the PMSG which are phase shifted by 120°. Outputs of matrix converter modules are connected in series to increase the output voltage and thus eliminate the need of a coupling step-up transformer. Moreover, dc-link capacitors found in conventional back-to-back converter topologies are eliminated in the proposed system. Proper multilevel output voltage generation and power sharing between converter modules are achieved through an advanced switching strategy. Simulation results are presented to validate the proposed modular matrix converter system, modulation method and control techniques.

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With the rapid development of world-wide wind energy generation using doubly fed induction generations (DFIGs), low voltage ride through (LVRT) has become a great concern. This paper focuses on a unique topology of DFIG called IG connection mode to help the DFIG ride through grid faults smoothly. Transient analysis of IG connection mode is carried out to derive the generator currents. With this analysis, the control strategy for IG connection mode DFIG was developed. From the simulation results, it is clearly visible that IG mode could work in both normal and low grid voltage conditions. Simulation results clearly show that the DFIG with the proposed mode switching control could smoothly ride through low voltage grid faults while satisfying grid code requirements.

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Les Murray and Judith Wright are two Australian poets who are widely read as landscape poets. While this framing offers valuable insights into their work it often fails to bring the importance into a contemporary context or to recognise the long tradition Australia has had with , to use Leo Marx’ term, “the complex pastoral”. As Ruth Blair reminds us in her chapter “Hugging the Shore: The Green Mountains of South-East Queensland” in The Littoral Zone: Australian Contexts and their Writers it is accepted that North America has a tradition of the complex pastoral mode but it should be remembered that Australia also has a long history of this form. Both Judith Wright’s and Les Murray’s poetry encourages active campaigning for the environment .These Australian poets are eco-pastoral poets whose poetry encourages active reading rather than passive reflections. Their poetry speaks to the strong connection between the lived everyday landscape and the imagination of past, present and future. Their work is imbued with a strong sense of ecocritical awareness while at the same time drawing on pastoral conventions. These two Australian poets do not offer idealistic pastoral notions but rather reveal the complexities of lived human/nonhuman relationships. This paper will discuss these complexities and how poetry can be experienced as literature in action—ways for readers to connect with and negotiate with the land they inhabit. The research for this paper was, in part, drawn from the responses that local community library groups offered after reading the works of these poets. What became evident from this research was the way the poetry made the readers think not only of landscape as a place of refuge from the urban technological world but also as a contemporary place with connection to agency that motivates readers into active change.

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Battery-supercapacitor hybrid energy storage systems can achieve better power and energy performances compared to their individual use. These hybrid systems require separate dc-dc converters, or at least one dc-dc converter for the supercapacitor bank, to connect them to the dc-link of the grid connecting inverter. However, the use of such dc-dc converters introduces additional cost and power losses. Therefore, the possibility of direct connection of energy storage systems, to the dc-link of a diode clamped 3-level inverter is investigated in this paper. Even though the proposed topology does not use dc-dc converters, a vector selection method is proposed to produce a similar control flexibility that is found in the separate dc-dc converter topology. The major issue with the proposed system is the imminent imbalance of the neutral point potential. A PWM technique with modified carriers is used to solve this problem. Simulations are carried out using MATLAB/SIMULINK to verify the efficacy of the proposed system.

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This paper explores the possibility of connecting two Wind Turbine Generators (WTG) to the grid using a single three level inverter. In the proposed system the rectified output of one WTG is connected across the upper dc-link capacitor of a standard diode clamped three level inverter. Similarly the rectified output of the other WTG is connected across the lower capacitor. This particular combination has several advantages such as, direct connection to the grid, reduced parts count, improved reliability and high power capacity. However, the major problem in the proposed system is the imminent imbalance of dc-link voltages. Under such conditions conventional modulation methods fail to produce desired voltage and current waveforms. A detailed analysis on this issue and a novel space vector modulation method, as the solution, are proposed in this paper. To track the Maximum power point of each WTG a power sharing algorithm is proposed. Simulation results are presented to attest the efficacy of the proposed system.

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This paper presents a new direct integration scheme for supercapacitors that are used to mitigate short term power fluctuations in wind power systems. The proposed scheme uses the popular dual inverter topology for grid connection as well as interfacing a supercapacitor bank. The dual inverter system is formed by cascading two 2-level inverters named as the “main inverter” and the “auxiliary inverter”. The main inverter is powered by the rectified output of a wind turbine coupled permanent magnet synchronous generator. The auxiliary inverter is directly connected to a super capacitor bank. This approach eliminates the need for an interfacing dc-dc converter for the supercapacitor bank and thus improves the overall efficiency. A detailed analysis on the effects of non-integer dynamically changing voltage ratio is presented. The concept of integrated boost rectifier is used to carry out the Maximum Power Point Tracking (MPPT) of the wind turbine generator. Another novel feature of this paper is the power reference adjuster which effectively manages capacitor charging and discharging at extreme conditions. Simulation results are presented to verify the efficacy of the proposed system in suppressing short term wind power fluctuations.

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The purpose of this study is to understand a small e-support firm’s response to the local e-readiness and the global e-business environment in a developing context. E-Support firms provide Web development and consultancy services to user organizations, assisting them in their uptake and maintenance of their Internet applications. Within the e-readiness research area, little is known about e-support firms, particularly in connection with their interaction with their local and the global e-business environment. As yet the emphasis on e-readiness studies has been at the national level. Nevertheless, the e-support sector is very significant in the successful adoption and diffusion of the Internet and related applications in any economy. It is thus important to understand how such firms relate to their e-business environments.That said, this study draws on the interpretive case study of a small e-support firm in Ghana, a developing context, to investigate the firm’s response to the e-readiness level of the local and the global e-business environment. Findings show that the firm could employ resources from the global environment to address most of the infrastructural challenges posed by a relatively poor local e-readiness context. However, its attempt to transfer advanced e-business technologies from the global e-business environment to the local e-business context did not succeed. This chapter offers implications for practice and research concerning the notion of reconciling local and global e-business environments in the small e-support sector.

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Heliothine moths (Lepidoptera: Heliothinae) include some of the world's most devastating pest species. Whereas the majority of nonpest heliothinae specialize on a single plant family, genus, or species, pest species are highly polyphagous, with populations often escalating in size as they move from one crop species to another. Here, we examine the current literature on heliothine host-selection behavior with the aim of providing a knowledge base for research scientists and pest managers. We review the host relations of pest heliothines, with a particular focus on Helicoverpa armigera (Hubner), the most economically damaging of all heliothine species. We then consider the important question of what constitutes a host plant in these moths, and some of the problems that arise when trying to determine host plant status from empirical studies on host use. The top six host plant families in the two main Australian pest species (H. armigera and Helicoverpa punctigera Wallengren) are the same and the top three (Asteraceae, Fabaceae, and Malvaceae) are ranked the same (in terms of the number of host species on which eggs or larvae have been identified), suggesting that these species may use similar cues to identify their hosts. In contrast, for the two key pest heliothines in the Americas, the Fabaceae contains approximate to 1/3 of hosts for both. For Helicoverpa zea (Boddie), the remaining hosts are more evenly distributed, with Solanaceae next, followed by Poaceae, Asteraceae, Malvaceae, and Rosaceae. For Heliothis virescens (F.), the next highest five families are Malvaceae, Asteraceae, Solanaceae, Convolvulaceae, and Scrophulariaceae. Again there is considerable overlap in host use at generic and even species level. H. armigera is the most widely distributed and recorded from 68 plant families worldwide, but only 14 families are recorded as a containing a host in all geographic areas. A few crop hosts are used throughout the range as expected, but in some cases there are anomalies, perhaps because host plant relation studies are not comparable. Studies on the attraction of heliothines to plant odors are examined in the context of our current understanding of insect olfaction, with the aim of better understanding the connection between odor perception and host choice. Finally, we discuss research into sustainable management of pest heliothines using knowledge of heliothine behavior and ecology. A coordinated international research effort is needed to advance our knowledge on host relations in widely distributed polyphagous species instead of the localized, piecemeal approaches to understanding these insects that has been the norm to date.

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By 2012 mobile devices had become the main interface for people to access information about anything from their current GPS position to the latest book reviews. What was less accessible were tools and techniques for writers to leverage this new technology to construct and distribute located stories. This project began with a series of master classes for local Brisbane writers to demonstrate processes and techniques for imagining, constructing and distributing stories. Most significantly, this project equipped writers with how to identify and adopt various mobile services and applications to research, produce and deliver packaged multi-modal content for readers to access and experience stories in the very locations from which they were inspired. Four stories by four writers were selected to be developed and published as location-based events in four different neighbourhoods across Brisbane. These writers were mentored throughout the writing process and a model was developed for them to simply upload several multi-modal chapters for access on location by readers using QR codes. These activities culminated in a major 25 day event presented by Brisbane City Council and supported by Brisbane Writers Festival and Queensland Writers Centre. The 'Street Reads' event presented the four stories on location in Cannon Hill, Darra, Toowong and West End. The significance of the Street Reads project went beyond extending the capacity for writers to access mobile technologies as a new platform for distributing stories. This event also motivated readers to travel to neighbourhoods to experience them in ways that had not previously imagined possible. These located stories were fictionalisations of actual events and characters that have current and historic importance to these places. These histories are hidden from view and yet can provide locals and visitors with a new found appreciation for the past and set an example for how neighbourhoods can become active stages for the sharing of stories inspiring a deeper connection with each other and an agency for participating in the development of the identity of the local places they inhabit together. Due to the success of the project and by employing more advanced tools now available, Street reads has been further developed by Brisbane City Council and is now available as a the Story City App available for download at itunes.

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Marsupials exhibit great diversity in ecology and morphology. However, compared to their sister group, the placental mammals, our understanding of many aspects of marsupial evolution remains limited. We use 101 mitochondrial genomes and data from 26 nuclear loci to reconstruct a dated phylogeny including 97% of extant genera and 58% of modern marsupial species. This tree allows us to analyze the evolution of habitat preference and geographic distributions of marsupial species through time. We found a pattern of mesic-adapted lineages evolving to use more arid and open habitats, which is broadly consistent with regional climate and environmental change. However, contrary to the general trend, several lineages subsequently appear to have reverted from drier to more mesic habitats. Biogeographic reconstructions suggest that current views on the connectivity between Australia and New Guinea/Wallacea during the Miocene and Pliocene need to be revised. The antiquity of several endemic New Guinean clades strongly suggests a substantially older period of connection stretching back to the Middle Miocene, and implies that New Guinea was colonized by multiple clades almost immediately after its principal formation.