Assessing the geographic resolution of exhaustive tabulation for geolocating Internet hosts

peer reviewedGeolocation of Internet hosts relies mainly on exhaustive tabulation techniques. Those techniques consist in building a database, that keeps the mapping between IP blocks and a geographic location. Relying on a single location for a whole IP block requires using a coarse enough geographic resolution. As this geographic resolution is not made explicit in databases, we try in this paper to better understand it by comparing the location estimates of databases with a well-established active measurements-based geolocation technique. We show that the geographic resolution of geolocation databases is far coarser than the resolution provided by active measurements for individual IP addresses. Given the lack of information in databases about the expected location error within each IP block, one cannot havemuch confidence in the accuracy of their location estimates. Geolocation databases should either provide information about the expected accuracy of the location estimates within each block, or reveal information about how their location estimates have been built, unless databases have to be trusted blindly.FP6-FET ANA (FP6-IST- 27489

Circulate and observe: a case study in the Cantanhede Traveling Library

Dissertação de Mestrado em Ciência da Informação apresentada à Faculdade de LetrasAs bibliotecas itinerantes prestam um importante serviço à sociedade, principalmente àqueles que residem em zonas mais longínquas das bibliotecas fixas. Nesta dissertação propusemo-nos a fazer um estudo de caso de uma delas: a Biblioteca Itinerante de Cantanhede. Pretendeu-se compreender o seu funcionamento, através da realização de visitas a essa biblioteca (para observar pessoas, serviços e meios), entrevistas aos responsáveis pelo funcionamento da biblioteca itinerante e, numa fase final, descrição e análise aos aspetos observados, tendo em conta os documentos padrão nessa temática (Diretrizes da IFLA para Bibliotecas Itinerantes). Para atingir estes objetivos, utilizámos o método qualitativo, implementando como estratégia o estudo de caso (à biblioteca itinerante) e como técnicas a observação (direta e não participante), a entrevista e a análise documental, sendo que a observação se traduziu em seis visitas à Biblioteca itinerante, percorrendo (quase) todas as paragens que estão programadas para cada uma delas (excluindo uma, por impossibilidade da própria instituição). Durante todas as seis visitas foram feitas paragens em 19 instituições. Foram observados um total de 416 utilizadores, na sua maioria do sexo masculino (212), representando 50,96% da amostra. Foi registado um número bastante significativo de utilizadores do sexo feminino (204), que representa um total de 49,04% da amostra. A escola que registou um maior número de alunos foi a Escola Garcia Bacelar (Tocha), com um total de 78 utilizadores. As conclusões do estudo revelam que a Biblioteca Itinerante presta um importante serviço a muitas escolas básicas e jardins de infância das zonas rurais de Cantanhede, levando literatura a quem, por motivos de distância da biblioteca fixa de Cantanhede, dificilmente teria acesso. Por tudo aquilo que foi observado (pessoas, serviços e meios), podemos dizer que esta Biblioteca cumpre as Diretrizes da IFLA para Bibliotecas Itinerantes (2014).The traveling libraries provide an important service to society, especially to those who live in remote areas of fixed libraries. In this dissertation we proposed to make a case study of one of them: the Cantanhede Itinerant Library. It was intended to understand how this specific Itinerant Library works, through visitations (to observe people, services and means), interviewing those responsible for the operation of the traveling library and, in a final phase, describing and analyzing the aspects observed, taking into account the standard documents in this theme (IFLA Guidelines for Traveling Libraries). To achieve these objectives, we used the qualitative method, implementing as a strategy the case study (to the itinerant library) and as observation techniques (direct and non-participant), interview and documentary analysis, and the observation was translated into six visits to the itinerant Library, traveling (almost) all the stops that are programmed for each of them (excluding one, due to the impossibility of the institution itself). In all six visits, stops were made at 19 institutions. A total of 416 users were observed, mostly males (212), representing 50.96% of the sample. A significant number of female users (204) were registered, representing a total of 49.04% of the sample. The school that registered the largest number of students was the Garcia Bacelar School (Tocha), with a total of 78 users. The findings of the study reveal that the Traveling Library provides an important service to many elementary schools and kindergartens in rural Cantanhede, bringing literature to those who, for reasons of distance from the Cantanhede fixed library, would hardly have access. For all that has been observed (people, services and media), we can say that this Library complies with the IFLA Guidelines for Itinerant Libraries (2014)

IP Geolocation Databases: Unreliable?

The most widely used technique for IP geolocation con- sists in building a database to keep the mapping between IP blocks and a geographic location. Several databases are available and are frequently used by many services and web sites in the Internet. Contrary to widespread belief, geolo- cation databases are far from being as reliable as they claim. In this paper, we conduct a comparison of several current geolocation databases -both commercial and free- to have an insight of the limitations in their usability. First, the vast majority of entries in the databases refer only to a few popular countries (e.g., U.S.). This creates an imbalance in the representation of countries across the IP blocks of the databases. Second, these entries do not re- flect the original allocation of IP blocks, nor BGP announce- ments. In addition, we quantify the accuracy of geolocation databases on a large European ISP based on ground truth information. This is the first study using a ground truth show- ing that the overly fine granularity of database entries makes their accuracy worse, not better. Geolocation databases can claim country-level accuracy, but certainly not city-level