988 resultados para Jensen, Sid


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8 hojas : fotografías baja calidad.

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96 hojas : ilustraciones, fotografías a color.

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This paper explores reasons for the high degree of variability in the sizes of ASes that have recently been observed, and the processes by which this variable distribution develops. AS size distribution is important for a number of reasons. First, when modeling network topologies, an AS size distribution assists in labeling routers with an associated AS. Second, AS size has been found to be positively correlated with the degree of the AS (number of peering links), so understanding the distribution of AS sizes has implications for AS connectivity properties. Our model accounts for AS births, growth, and mergers. We analyze two models: one incorporates only the growth of hosts and ASes, and a second extends that model to include mergers of ASes. We show analytically that, given reasonable assumptions about the nature of mergers, the resulting size distribution exhibits a power law tail with the exponent independent of the details of the merging process. We estimate parameters of the models from measurements obtained from Internet registries and from BGP tables. We then compare the models solutions to empirical AS size distribution taken from Mercator and Skitter datasets, and find that the simple growth-based model yields general agreement with empirical data. Our analysis of the model in which mergers occur in a manner independent of the size of the merging ASes suggests that more detailed analysis of merger processes is needed.

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Recent studies have noted that vertex degree in the autonomous system (AS) graph exhibits a highly variable distribution [15, 22]. The most prominent explanatory model for this phenomenon is the Barabási-Albert (B-A) model [5, 2]. A central feature of the B-A model is preferential connectivity—meaning that the likelihood a new node in a growing graph will connect to an existing node is proportional to the existing node’s degree. In this paper we ask whether a more general explanation than the B-A model, and absent the assumption of preferential connectivity, is consistent with empirical data. We are motivated by two observations: first, AS degree and AS size are highly correlated [11]; and second, highly variable AS size can arise simply through exponential growth. We construct a model incorporating exponential growth in the size of the Internet, and in the number of ASes. We then show via analysis that such a model yields a size distribution exhibiting a power-law tail. In such a model, if an AS’s link formation is roughly proportional to its size, then AS degree will also show high variability. We instantiate such a model with empirically derived estimates of growth rates and show that the resulting degree distribution is in good agreement with that of real AS graphs.

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Tugann an staidéar taighde aghaidh ar an dátheangachas i bPoblacht na hÉireann agus go háirithe ar thuairimí dhaoine óga dátheangacha sa 21ú haois. Is é cuspóir an staidéir ná iniúchadh a dhéanamh ar mheonta déagóirí Éireannacha dátheangacha i leith na Gaeilge agus a gcuid aitheantais mar dhéagóirí dátheangacha. Déanann an staidéar anailís ar mheonta daltaí a fhreastalaíonn ar iar-bhunscoileanna lán-Ghaeilge. Féachtar ar thuairimí tuismitheoirí, múinteoirí agus iar-scoláirí freisin. Is í príomhcheist an staidéir seo ná: Cad iad meonta déagóirí Éireannacha dátheangacha i leith teanga na Gaeilge agus cad iad a n-aitheantais mar Éireannaigh óga dátheangacha? Baineadh úsáid as modhanna cáilíochtúla idir agallaimh, agallamh grúpa, scríbhneoireacht phearsanta agus ríomhphoist chun eolas a bhailiú i scoil an staidéir cháis. Roghnaíodh modh cainníochtúil an cheistneora náisiúnta chun cur leis an eolas. Tugann an taighde le tuiscint go mothaíonn déagóirí Éireannacha dearfach faoi theanga na Gaeilge agus faoin a gcuid aitheantais mar dhaoine dátheangacha. Léiríonn torthaí an taighde gurb ionann teanga na Gaeilge dóibh agus seoid luachmhar a sholáthraíonn buntáistí, deiseanna agus féidearthachtaí dóibh. Maidir le cruthú aitheantais, chuaigh formhór na ndéagóirí i scoil an staidéir cháis i dtreo a ndá ghrúpa teangeolaíochta agus chruthaigh siad “linguistic brokerage” (Shenk, 2008) a tharraing a taobh Gaelach is Béarla le chéile. Mothaíonn formhór na ndéagóirí dátheangacha seo go bhfuil aitheantas amháin acu ach go bhfuil an dá theanga, an dá chultúr agus an dá pháirt dá saoil mar pháirt den gcomhaitheantas sin. Ach ba léir go raibh éagsúlachtaí i measc na rannpháirtithe freisin. Tacaíonn torthaí an taighde le gnéithe den litríocht ar a rinneadh athbhreithniú chun ról lárnach na teanga i gcruthú aitheantais an déagóra a léiriú. Cuireann an taighde seo leis an réimse toisc go soláthraíonn sé eolas luachmhar agus fiúntach faoin dátheangachas agus aitheantas i bPoblacht na hÉireann sa 21ú haois.

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Is é atá sa tráchtas ná staidéar ar logainmneacha agus dinnseanchas ceantair Ghaeltachta Bhéal Átha an Ghaorthaidh. Ins na léarscáileanna a cruthaíodh tá iarracht ar na logainmneacha a líonadh isteach chomh cruinn is ab fhéidir agus furasta iad a aimsiú mar go bhfuil iomlán an eolais ar leathanach amháin. Cuireadh leis an eolas seo trí úsáid foinsí béaloidis a bhain leis an gceantar nó baile fearainn agus is iad Páipéir Uí Dhonnchadha agus Cnuasach Bhéaloideas Éireann is mó a úsáideadh. Tá a lán eolas a bhailigh An tAth Ó Donnchadha faoin nGuagán scríte anseo agus tugann sé le fios a lán dúinn ar an áit agus imeachtaí na haimsire sin.

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This paper presents a design science approach to solving persistent problems in the international shipping eco system by creating the missing common information infrastructures. Specifically, this paper reports on an ongoing dialogue between stakeholders in the shipping industry and information systems researchers engaged in the design and development of a prototype for an innovative IT-artifact called Shipping Information Pipeline which is a kind of “an internet” for shipping information. The instrumental aim is to enable information seamlessly to cross the organizational boundaries and national borders within international shipping which is a rather complex domain. The intellectual objective is to generate and evaluate the efficacy and effectiveness of design principles for inter-organizational information infrastructures in the international shipping domain that can have positive impacts on global trade and local economies.

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Is éard atá curtha romham agam sa tráchtas seo ná an t-úrscéal iar-nua-aoiseach sa Ghaeilge a phlé; chun aitheantas a thabhairt don seánra mar rud ar leith; chun a fhréamhacha a aimsiú agus a thréithe sainiúla a léiriú. Féachaim anseo lena léiriú go bhfuil baint shainiúil ag an úrscéal iar-nua-aoiseach sa Ghaeilge le stair shochteangeolaíoch agus liteartha na hÉireann. Chruthaigh scríbhneoirí Béarla na hÉireann, ar nós Joyce, Beckett agus Flann O’Brien (Brian Ó Nualláin), cur chuige liteartha a raibh toradh ollmhór aige ar chúrsaí liteartha an domhain – go háirithe sa chomhthéacs (iar)-nua-aoiseach. Léireoidh mé gur tháinig an cur chuige seo chun cinn de bharr an choibhnis shainiúil atá ag muintir na hÉireann le teanga – coibhneas atá ginte i nguagacht faoin rud is teanga féin ann. Áitím gur eascair an ghuagacht seo as an athrú stádais – ó phríomhtheanga go mionteanga – a tharla don Ghaeilge. Áitím gur cruthaíodh feasacht ar fholús i bhféiniúlacht na tíre nuair a tharla an t-athrú sin agus go raibh tionchar ag an bhfeasacht seo ar litríocht na hÉireann – idir Ghaeilge agus Bhéarla. Is minic a fhéachann an túrscéal iar-nua-aoiseach, i ngach teanga ina gcleachtar a leithéid, le staidéar a dhéanamh ar na slite ina gcruthaítear brí sa saol trí theanga agus trí reacaireacht. Murab ionann is a mbíonn i gceist san úrscéal ‘traidisiúnta’ – an t-úrscéal ‘réadach’ mar a tuigtear leis – glacann iar-nua-aoiseachas leis go bhfuil solúbthacht agus saorgacht i ngach léiriú ar an mbrí seo. Léiríonn na húrscéalta atá faoi chaibidil sa tráchtas seo an-doimhneacht liteartha. Is saothair fhéinchomhfhiosacha agus mheitificseanúla iad a thaispeánann éiginnteacht i leith brí absalóidigh. Oibríonn siad mar léiriú ar fheidhm na teanga sa saol agus ar na slite ina gcruthaíonn gach reacaireacht a fírinne féin. Cé gur tréithe iar-nua-aoiseacha iad siúd, is tréithe iad chomh maith a bhaineann le stádas na mionteanga.

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This longitudinal study tracked third-level French (n=10) and Chinese (n=7) learners of English as a second language (L2) during an eight-month study abroad (SA) period at an Irish university. The investigation sought to determine whether there was a significant relationship between length of stay (LoS) abroad and gains in the learners' oral complexity, accuracy and fluency (CAF), what the relationship was between these three language constructs and whether the two learner groups would experience similar paths to development. Additionally, the study also investigated whether specific reported out-of-class contact with the L2 was implicated in oral CAF gains. Oral data were collected at three equidistant time points; at the beginning of SA (T1), midway through the SA sojourn (T2) and at the end (T3), allowing for a comparison of CAF gains arising during one semester abroad to those arising during a subsequent semester. Data were collected using Sociolinguistic Interviews (Labov, 1984) and adapted versions of the Language Contact Profile (Freed et al., 2004). Overall, the results point to LoS abroad as a highly influential variable in gains to be expected in oral CAF during SA. While one semester in the TL country was not enough to foster statistically significant improvement in any of the CAF measures employed, significant improvement was found during the second semester of SA. Significant differences were also revealed between the two learner groups. Finally, significant correlations, some positive, some negative, were found between gains in CAF and specific usage of the L2. All in all, the disaggregation of the group data clearly illustrates, in line with other recent enquiries (e.g. Wright and Cong, 2014) that each individual learner's path to CAF development was unique and highly individualised, thus providing strong evidence for the recent claim that SLA is "an individualized nonlinear endeavor" (Polat and Kim, 2014: 186).

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Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.