Proceedings of the 12th International Conference on Digital Preservation

The 12th International Conference on Digital Preservation (iPRES) was held on November 2-6, 2015 in Chapel Hill, North Carolina, USA. There were 327 delegates from 22 countries. The program included 12 long papers, 15 short papers, 33 posters, 3 demos, 6 workshops, 3 tutorials and 5 panels, as well as several interactive sessions and a Digital Preservation Showcase

Proceedings of the 12th International Conference on Digital Preservation

The 12th International Conference on Digital Preservation (iPRES) was held on November 2-6, 2015 in Chapel Hill, North Carolina, USA. There were 327 delegates from 22 countries. The program included 12 long papers, 15 short papers, 33 posters, 3 demos, 6 workshops, 3 tutorials and 5 panels, as well as several interactive sessions and a Digital Preservation Showcase

Migration Performance for Legacy Data Access

We present performance data relating to the use of migration in a system we are creating to provide web access to heterogeneous document collections in legacy formats. Our goal is to enable sustained access to collections such as these when faced with increasing obsolescence of the necessary supporting applications and operating systems. Our system allows searching and browsing of the original files within their original contexts utilizing binary images of the original media. The system uses static and dynamic file migration to enhance collection browsing, and emulation to support both the use of legacy programs to access data and long-term preservation of the migration software. While we provide an overview of the architectural issues in building such a system, the focus of this paper is an in-depth analysis of file migration using data gathered from testing our software on 1,885 CD-ROMs and DVDs. These media are among the thousands of collections of social and scientific data distributed by the United States Government Printing Office (GPO) on legacy media (CD-ROM, DVD, floppy disk) under the Federal Depository Library Program (FDLP) over the past 20 years

I Am Error

I Am Error is a platform study of the Nintendo Family Computer (or Famicom), a videogame console first released in Japan in July 1983 and later exported to the rest of the world as the Nintendo Entertainment System (or NES). The book investigates the underlying computational architecture of the console and its effects on the creative works (e.g. videogames) produced for the platform. I Am Error advances the concept of platform as a shifting configuration of hardware and software that extends even beyond its ‘native’ material construction. The book provides a deep technical understanding of how the platform was programmed and engineered, from code to silicon, including the design decisions that shaped both the expressive capabilities of the machine and the perception of videogames in general. The book also considers the platform beyond the console proper, including cartridges, controllers, peripherals, packaging, marketing, licensing, and play environments. Likewise, it analyzes the NES’s extension and afterlife in emulation and hacking, birthing new genres of creative expression such as ROM hacks and tool-assisted speed runs. I Am Error considers videogames and their platforms to be important objects of cultural expression, alongside cinema, dance, painting, theater and other media. It joins the discussion taking place in similar burgeoning disciplines—code studies, game studies, computational theory—that engage digital media with critical rigor and descriptive depth. But platform studies is not simply a technical discussion—it also keeps a keen eye on the cultural, social, and economic forces that influence videogames. No platform exists in a vacuum: circuits, code, and console alike are shaped by the currents of history, politics, economics, and culture—just as those currents are shaped in kind

Thwarting Attacks in Malcode-Bearing Documents by Altering Data Sector Values

Embedding malcode within documents provides a convenient means of attacking systems. Such attacks can be very targeted and difficult to detect to stop due to the multitude of document-exchange vectors and the vulnerabilities in modern document processing applications. Detecting malcode embedded in a document is difficult owing to the complexity of modern document formats that provide ample opportunity to embed code in a myriad of ways. We focus on Microsoft Word documents as malcode carriers as a case study in this paper. To detect stealthy embedded malcode in documents, we develop an arbitrary data transformation technique that changes the value of data segments in documents in such a way as to purposely damage any hidden malcode that may be embedded in those sections. Consequently, the embedded malcode will not only fail but also introduce a system exception that would be easily detected. The method is intended to be applied in a safe sandbox, the transformation is reversible after testing a document, and does not require any learning phase. The method depends upon knowledge of the structure of the document binary format to parse a document and identify the specific sectors to which the method can be safely applied for malcode detection. The method can be implemented in MS Word as a security feature to enhance the safety of Word documents

Spatial-Temporal distribution of phytoplankton biomass during a coastal upwelling episode obtained from remote sensing and in situ data

Tese de mestrado, Ciências do Mar, Universidade de Lisboa, Faculdade de Ciências, 2022Nos últimos anos, os blooms de algas nocivas tornaram-se um objeto de estudo importante para a comunidade científica devido ao crescimento mundial do fenómeno. Contudo, os blooms de algas não são necessariamente tóxicos, apesar de nocivos. Existem dois modos para serem consideradas nocivos: a primeira é pela produção de toxinas pelas próprias algas; a segunda pela acumulação de biomassa que, por morte das células, provocam condições de anoxia (ausência de oxigénio), lesivas para o ecossistema. No entanto, os mecanismos físicos e biológicos que os desencadeiam não são totalmente conhecidos. Os mecanismos físicos (a temperatura da superfície do mar, a estratificação da coluna de água, o forçamento do vento, entre outros) controlam a biomassa fitoplanctónica possibilitando, em certos casos, uma acumulação da mesma devido à disponibilidade de nutrientes na coluna de água. Daí, é importante compreender de que forma os mecanismos físicos podem produzir as condições favoráveis ao aparecimento de blooms de algas nocivas. Um destes é o afloramento costeiro, mecanismo abordado na dissertação. O objetivo da tese é o estudo da variação espácio-temporal da biomassa fitoplanctónica no Noroeste da Península Ibérica (Figueira da Foz, Portugal) durante um episódio de afloramento costeiro. De forma a avaliar a distribuição espácio-temporal do fitoplâncton recorreu-se a dados de deteção remota e dados in situ (concentração em clorofila-a, Chl-a, índice de biomassa do fitoplâncton), obtidos durante uma campanha oceanográfica de 12 a 19 de setembro de 2019. O presente trabalho foca as duas primeiras semanas de setembro de 2019, período no qual ocorreu uma campanha oceanográfica. Esta tese foi realizada no âmbito do Projeto HabWAVE, com o objetivo de estudar a formação dos blooms de algas nocivas no noroeste da costa portuguesa através de processos físicos e biológicos, aplicando os dados de deteção remota e in situ. A primeira etapa do trabalho consistiu em verificar quais as imagens de satélite disponíveis, de onde foram analisadas as concentrações da clorofila-a (Chl-a) e a temperatura da superfície do mar (SST- Sea Surface Temperature). Em diversos dias houve ausência de imagens devido à cobertura nebulosa presente durante o mês de setembro de 2019. A SST foi igualmente obtida a partir da solução numérica do modelo ROMS. Recorreu-se a produtos de satélites com resoluções espaciais iguais ou inferiores a 1 km, para a concentração de clorofila-a e para a temperatura da superfície do mar. Por turno, o forçamento do vento e as correntes oceânicas foram obtidas a partir das soluções numéricas de diferentes modelos: o ECMWF-IFS e o ROMS, respetivamente. No caso dos produtos de clorofila-a fez-se uma análise prévia dos algoritmos disponíveis através da sua comparação com os dados in situ existentes (matchups). A análise dos matchups foi efetuada a partir de dois parâmetros estatísticos, o erro quadrático médio e o viés, que permitiram averiguar qual o produto de Chl-a mais apropriado para representar a sua variabilidade espacial na região de estudo. Com base nestes critérios foi selecionado o algoritmo de Chl-a “Piscismod Iberia” em relação aos algoritmos da Chl_NN e Chl_OC4Me (provenientes do sensor Ocean and Land Colour Instrument – OLCI), e do Ocean Colour Climate Change Iniciative (OC - CCI). O produto de SST selecionado é proveniente do sensor Sea and Land Surface Temperature Radiometer (SLSTR), do Group of High Resolution Sea Surface Temperature (GHRSST). Este sensor permite estimar a temperatura da superfície do mar através da calibração altamente precisa de três canais infravermelhos (S7-S8-S9). Os resultados mostram sucessivos ciclos de intensificação e relaxamento do forçamento do vento favorável ao afloramento (componente along-shore) nas duas primeiras semanas de setembro de 2019. A variabilidade no campo do vento afeta a distribuição espacial da SST, ou seja, a intensificação da componente along-shore do vento produzirá uma intensificação do afloramento costeiro e um relaxamento do vento causará uma regressão do afloramento costeiro. A comparação entre as soluções do modelo hidrodinâmico para a temperatura da superfície mostrou que o modelo reproduz valores semelhantes aos do satélite, no entanto, com uma subestimação dos valores da SST. A análise das distribuições de concentração de clorofila-a mostrou uma forte correlação com a distribuição espacial da SST, com elevados valores de Chl-a associados a baixos valores de SST. Contudo, a partir do dia 10 de setembro de 2019 em diante, observa-se que os valores elevados de clorofila-a não se associam necessariamente a temperaturas mais frias e em algumas áreas de baixa temperatura os valores de clorofila-a também são baixos. De forma a compreender este fenómeno estudou-se a variabilidade da costa para o largo (cross-shore), de onde se observou que a fraca concentração de clorofila-a está dependente da intensificação do forçamento do vento que, por sua vez, fortalece a componente cross shore do transporte de Ekman. De acordo com a literatura, a interpretação sobre o desfasamento visual entre a Chl-a e a SST, observadas no dia 11 de setembro, dever-se-á à forte divergência, e consequentemente afloramento de águas subsuperficiais, induzida pelo aumento da componente along shore do vento. Posteriormente, analisaram-se, em pormenor, os dias 5, 10 e 11 de setembro, por apresentarem os maiores picos de ventos favoráveis ao afloramento costeiro. Nestes dias, a concordância visual entre as correntes oceânicas (modeladas pelo modelo ROMS) com a distribuição espacial da Chl-a e da SST mostraram que o modelo tem um melhor desempenho com as imagens de satélite para a distribuição espacial na região costeira, facto não verificado para o oceano aberto. De seguida, calcularam-se e comparam-se os campos da divergência horizontal que permitem inferir os locais onde o maior afloramento costeiro é mais intenso. O máximo de divergência costeira offshore observada é coincidente com as baixas concentrações clorofila-a, na mesma faixa de latitudes e longitudes. De seguida, três latitudes distintas (40.30°N, 40.19°N e 40.11°N) foram representadas em profundidade, para as correntes oceânicas e para a temperatura do mar. Com o decorrer do tempo foi visualizada uma progressão das camadas mais frias, associadas a uma intensificação do campo do vento. No caso das correntes oceânicas, uma componente maioritariamente para sul é observada em todos os dias. Contudo, nos dias 10 e 11, que correspondem aos dias de máxima intensidade do vento, verifica-se a formação de um jato costeiro confinado na região costeira. Logo, a baixa concentração de clorofila-a é justificada pela intensificação da componente along-shore do forçamento do vento que produz um máximo de divergência costeira. O máximo de divergência costeira observado não se encontra junto da linha costeira devido à interação entre a camada de Ekman da superfície e a camada de Ekman do fundo nas regiões menos profundas. Com a persistência do forçamento do vento, o campo de divergência vai progredir para fora com a evolução do afloramento costeiro. Por sua vez, permite a formação de um jato costeiro para sul coincidente com o sinal de baixa concentração de clorofila-a observada pelos dados de satélites.In recent years, harmful algal blooms have become an important object of study for the scientific community due to the worldwide growth of the phenomenon. However, algal blooms are not necessarily toxic, albeit harmful. There are two ways to be considered harmful: the first is by the production of toxins by the algae themselves; the second is due to the accumulation of biomass which, due to cell death, causes conditions of anoxia (lack of oxygen), which are harmful to the ecosystem. However, the physical and biological mechanisms that trigger them are not fully understood. Physical mechanisms (sea surface temperature, water column stratification, wind forcing, among others) control the phytoplankton biomass, enabling, in certain cases, its accumulation due to the availability of nutrients in the water column. Hence, it is important to understand how physical mechanisms can produce the conditions favourable for the emergence of harmful algal blooms. One of these is the coastal upwelling, a mechanism addressed in the dissertation. The aim of this thesis is to study the spatiotemporal variation of phytoplankton biomass in the Northwest of the Iberian Peninsula (Figueira da Foz, Portugal) during an episode of coastal upwelling. In order to assess the spatiotemporal distribution of phytoplankton, remote sensing data and in situ data (chlorophyll-a, concentration, Chl-a, phytoplankton biomass index) were used, obtained during an oceanographic campaign from 12 to 19 September of 2019. The present work focuses on the first two weeks of September 2019, a period in which an oceanographic campaign took place. This thesis was carried out within the scope of the HabWAVE Project, with the aim of studying the formation of harmful algal blooms in the northwest of the Portuguese coast through physical and biological processes, applying remote sensing and in situ data. The first stage of the work consisted of verifying which satellite images were available, from which the concentrations of chlorophyll-a (Chl-a), and the sea surface temperature (SST) were analysed. For several days there was an absence of images due to the cloudy coverage present during the month of September 2019. The SST was also obtained from the numerical solution of the ROMS model. Satellite products with spatial resolutions equal to or less than 1 km were used for the concentration of chlorophyll-a and for the temperature of the sea surface. In turn, the wind forcing, and ocean currents were provided by numerical solutions of different models, ECMWF-IFS, and ROMS, respectively. In the case of chlorophyll-a products, the available algorithms were previously analysed by comparing them with existing in situ data (matchups). The matchup analysis was performed using two statistical parameters (mean square error and bias) that allow us to determine which Chl-a product is most appropriate to represent its spatial variability in the study region. Based on these criteria, the Chl-a algorithm of Piscismod Iberia was selected in relation to the algorithms of Chl_NN and Chl_OC4Me (derived from the sensor Ocean and Land Colour Instrument - OLCI), and the Ocean Colour Climate Change Initiative (OC - CCI). The selected SST product comes from the Group of High-Resolution Sea Surface Temperature (GHRSST) sensor Sea, and Land Surface Temperature Radiometer (SLSTR). This sensor allows the estimation of sea surface temperature measurements through the highly accurate calibration of three infrared channels (S7-S8-S9). The results show successive upwelling-favourable wind forcing intensification and relaxation cycles (along-shore component) in the first two weeks of September 2019. The variability in the wind field affects the spatial distribution of the SST, that is, the intensification of the along-shore component. shore wind will produce an intensification of the coastal upwelling and a relaxation of the wind will cause a regression of the coastal upwelling. The comparison between the hydrodynamic model solutions for surface temperature showed that the model reproduces values similar to those of the satellite, however, with an underestimation of the SST values. The concentration of chlorophyll-a was shown to correlate with the spatial distribution of SST, with high Chl-a concentrations associated to low SST values. However, from September 10, 2019, onwards, it was observed that high chlorophyll-a concentrations are not necessarily associated with cooler temperatures, and that in some areas with low temperature the Chl-a values are also low. In order to understand this phenomenon, the variability of the coast to the sea (cross-shore) was studied, from which it was observed that the weak concentration of chlorophyll-a is dependent on the intensification of the wind forcing which, in turn, strengthens the cross-shore component of Ekman's transport. According to the literature, the interpretation of the visual lag between Chl-a and SST, observed on September 11th , should be due to the strong coastal divergence, and consequent upwelling of subsurface waters, induced by the increase in the along-shore component of the wind. Subsequently, the 5th, 10th and 11th of September were analysed in detail, as they presented the highest peaks of favourable winds for the coastal upwelling. These days, the visual agreement between ocean currents (modelled by the ROMS model) with the spatial distribution of Chl-a and SST showed that the model performs better with satellite images for the spatial distribution in the coastal region, which is not true, for the ocean. Then, the horizontal divergence fields were calculated and compared, allowing to infer the places where coastal upwelling is stronger. The maximum observed offshore coastal divergence coincides with the low concentrations of chlorophyll-a, in the same range of latitudes and longitudes. Then, three distinct latitudes (40.30°N, 40.19°N and 40.11°N) were plotted in depth, for ocean currents and for sea temperature. Over time, a progression of the cooler layers was seen, associated with an intensification of the wind field. In the case of ocean currents, a mostly southerly component is observed every day. However, on days 10 and 11, corresponding to peak wind intensifies, a coastal jet confined to the coastal region is formed. Therefore, the low concentration of chlorophyll-a is justified by the intensification of the along-shore component of the wind forcing that produces a maximum of coastal divergence. The maximum observed coastal divergence is not found near the shoreline due to the interaction between the surface Ekman layer, and the bottom Ekman layer in the shallower regions. With the persistence of the wind forcing, the divergence field will progress offshore with the evolution of the coastal upwelling. In turn, it allows the formation of a coastal jet to the south coincident with the signal of low concentration of chlorophyll-a observed by satellite data

ViPEr-HiSS: A Case for Storage Design Tools

The viability of large-scale multimedia applications, depends on the performance of storage systems. Providing cost-effective access to vast amounts of video, image, audio, and text data, requires (a) proper configuration of storage hierarchies as well as (b) efficient resource management techniques at all levels of the storage hierarchy. The resulting complexities of the hardware/software co-design in turn contribute to difficulties in making accurate predictions about performance, scalability, and cost-effectiveness of a storage system. Moreover, poor decisions at design time can be costly and problematic to correct in later stages of development. Hence, measurement of systems after they have been developed is not a desirable approach to predicting their performance. What is needed is the ability to evaluate the system's design while there are still opportunities to make corrections to fundamental design flaws. In this paper we describe the framework of ViPEr-HiSS, a tool which facilitates design, development, and subsequent performance evaluation of designs of multimedia storage hierarchies by providing mechanisms for relatively easy experimentation with (a) system configurations as well as (b) application- and media-aware resource management techniques. (Also cross-referenced as UMIACS-TR-99-69

An investigation into the management of electronic records in the public sector in Lesotho.

Thesis (MIS)-University of KwaZulu-Natal, Pietermaritzburg, 2004.Government computers are generating enormous volumes of e-records such as e-mails, word processed documents and databases. The immediate challenge of the public sector is therefore to preserve these digital records and make them accessible to future generations. The present study was conducted to investigate the management of e-records in the public sector in Lesotho. The objectives of the study guided the researcher to find out what IT infrastructure and resources existed. The study looked at which records were currently being created and strategies and policies used in managing those records. The archival legislation was reviewed to assess how it affected e-records. An e-records model suitable for managing e-records in Lesotho was suggested. The study adopted the descriptive research by utilizing the case study approach. Interview schedules were employed for data gathering, together with observations. The literature review guided the content of the interview schedule. Data was analyzed according to the objectives of the study. The overall findings revealed that the public sector in Lesotho was not managing its e­-records satisfactorily. The public sector did not have legislation that specifically dealt with managing e-records, there were no written policies, strategies and guidelines were non-existent. The study also revealed that there were no qualified personnel with expertise and skills in the management of e-records in the public sector. The study's conclusions and recommendations were that the public sector be allocated more resources and IT infrastructure. Staff should be trained, policies should be formulated, legislation should be amended to accommodate e-records and, lastly, the study recommended that the public sector in Lesotho should adopt the South African e­-records management model