title: Applying Wikipedia to Interactive Information Retrieval

authors: Milne, David N.

subjects: Interactive Information Retrieval

abstract: There are many opportunities to improve the interactivity of information retrieval systems beyond the ubiquitous search box. One idea is to use knowledge bases—e.g. controlled vocabularies, classification schemes, thesauri and ontologies—to organize, describe and navigate the information space. These resources are popular in libraries and specialist collections, but have proven too expensive and narrow to be applied to everyday webscale search. Wikipedia has the potential to bring structured knowledge into more widespread use. This online, collaboratively generated encyclopaedia is one of the largest and most consulted reference works in existence. It is broader, deeper and more agile than the knowledge bases put forward to assist retrieval in the past. Rendering this resource machine-readable is a challenging task that has captured the interest of many researchers. Many see it as a key step required to break the knowledge acquisition bottleneck that crippled previous efforts. This thesis claims that the roadblock can be sidestepped: Wikipedia can be applied effectively to open-domain information retrieval with minimal natural language processing or information extraction. The key is to focus on gathering and applying human-readable rather than machine-readable knowledge. To demonstrate this claim, the thesis tackles three separate problems: extracting knowledge from Wikipedia; connecting it to textual documents; and applying it to the retrieval process. First, we demonstrate that a large thesaurus-like structure can be obtained directly from Wikipedia, and that accurate measures of semantic relatedness can be efficiently mined from it. Second, we show that Wikipedia provides the necessary features and training data for existing data mining techniques to accurately detect and disambiguate topics when they are mentioned in plain text. Third, we provide two systems and user studies that demonstrate the utility of the Wikipedia-derived knowledge base for interactive information retrieval.

text: Applying Wikipedia to Interactive Information Retrieval There are many opportunities to improve the interactivity of information retrieval systems beyond the ubiquitous search box. One idea is to use knowledge bases—e.g. controlled vocabularies, classification schemes, thesauri and ontologies—to organize, describe and navigate the information space. These resources are popular in libraries and specialist collections, but have proven too expensive and narrow to be applied to everyday webscale search. Wikipedia has the potential to bring structured knowledge into more widespread use. This online, collaboratively generated encyclopaedia is one of the largest and most consulted reference works in existence. It is broader, deeper and more agile than the knowledge bases put forward to assist retrieval in the past. Rendering this resource machine-readable is a challenging task that has captured the interest of many researchers. Many see it as a key step required to break the knowledge acquisition bottleneck that crippled previous efforts. This thesis claims that the roadblock can be sidestepped: Wikipedia can be applied effectively to open-domain information retrieval with minimal natural language processing or information extraction. The key is to focus on gathering and applying human-readable rather than machine-readable knowledge. To demonstrate this claim, the thesis tackles three separate problems: extracting knowledge from Wikipedia; connecting it to textual documents; and applying it to the retrieval process. First, we demonstrate that a large thesaurus-like structure can be obtained directly from Wikipedia, and that accurate measures of semantic relatedness can be efficiently mined from it. Second, we show that Wikipedia provides the necessary features and training data for existing data mining techniques to accurately detect and disambiguate topics when they are mentioned in plain text. Third, we provide two systems and user studies that demonstrate the utility of the Wikipedia-derived knowledge base for interactive information retrieval.

year: 2010

title: Oxidation of surface sediment: effects of disturbance depth and seawater flow speed

authors: Vopel, Kay

subjects: cohesive sediment

abstract: Periodic disturbance of surface sediment is a natural feature of marine environments. Following exposure to oxygenated seawater, the disturbed sediment oxidises leading to the recovery of its surface chemistry. Despite its importance for the ecology of the sediment–water interface, the dynamics of this recovery is not well known. We studied the effects of disturbance depth and seawater flow speed on the oxidation of estuarine cohesive sediment in a laboratory flume with microelectrodes. We removed surface sediment to 2 depths (5 and 50 mm) and then observed changes in sediment O₂ distribution and consumption over 1 h under conditions of slow and fast flow (3.5 and 7.5 cm s–1). Measurements were repeated 1 d later. The consumption of O₂ in the treated sediments reached a ‘quasi stable state’ within 7 h (50 mm depth) and 16 h (5 mm depth) characterised by very slow changes due to slow oxidation of reduced solids. Faster flow increased the rate at which sediment from 50 mm depth oxidised but not that of the sediment from 5 mm depth. After 20 to 24 h, sediments disturbed to 50 and 5 mm depths still differed in O₂ distribution and consumption, both from each other and from the pre-treatment sediment. Differences in the response of pore water O₂ distribution to an abrupt increase in flow speed (3.5 to 7.5 cm s–1) were also still evident at this time. Our measurements confirmed the results of previous theoretical analyses in that they indicate that the duration of the recovery of the surface sediment chemistry from disturbance and the chemical properties of the recovering sediment are controlled by the kinetics of solute and solid oxidation. Oxidation of reduced solids in disturbed sediment can result in a characteristic chemical signature at the sediment surface that lasts in the order of at least days.

text: Oxidation of surface sediment: effects of disturbance depth and seawater flow speed Periodic disturbance of surface sediment is a natural feature of marine environments. Following exposure to oxygenated seawater, the disturbed sediment oxidises leading to the recovery of its surface chemistry. Despite its importance for the ecology of the sediment–water interface, the dynamics of this recovery is not well known. We studied the effects of disturbance depth and seawater flow speed on the oxidation of estuarine cohesive sediment in a laboratory flume with microelectrodes. We removed surface sediment to 2 depths (5 and 50 mm) and then observed changes in sediment O₂ distribution and consumption over 1 h under conditions of slow and fast flow (3.5 and 7.5 cm s–1). Measurements were repeated 1 d later. The consumption of O₂ in the treated sediments reached a ‘quasi stable state’ within 7 h (50 mm depth) and 16 h (5 mm depth) characterised by very slow changes due to slow oxidation of reduced solids. Faster flow increased the rate at which sediment from 50 mm depth oxidised but not that of the sediment from 5 mm depth. After 20 to 24 h, sediments disturbed to 50 and 5 mm depths still differed in O₂ distribution and consumption, both from each other and from the pre-treatment sediment. Differences in the response of pore water O₂ distribution to an abrupt increase in flow speed (3.5 to 7.5 cm s–1) were also still evident at this time. Our measurements confirmed the results of previous theoretical analyses in that they indicate that the duration of the recovery of the surface sediment chemistry from disturbance and the chemical properties of the recovering sediment are controlled by the kinetics of solute and solid oxidation. Oxidation of reduced solids in disturbed sediment can result in a characteristic chemical signature at the sediment surface that lasts in the order of at least days.

year: 2010

title: Supervising research in Māori cultural contexts: a decolonizing, relational response

authors: Berryman, Mere

abstract: We have collaborated for 25 years as indigenous Māori and non- Māori researchers undertaking research with Māori families, their schools and communities. We have endeavored to meet our responsibilities to the Māori people (indigenous inhabitants of New Zealand) and communities with whom we have researched, as well as meet the requirements and responsibilities of our academic institutions. In this paper, we reflect on the implications of these responsibilities for our work as supervisors of master’s and doctoral students (Māori and non-Māori) who seek to draw on decolonizing methodologies as they undertake research in Māori cultural contexts. We draw on the experiences and interactions we have had with four different postgraduate students whose research on improving educational outcomes for Māori students has required them to engage and participate in Māori cultural contexts.

text: Supervising research in Māori cultural contexts: a decolonizing, relational response We have collaborated for 25 years as indigenous Māori and non- Māori researchers undertaking research with Māori families, their schools and communities. We have endeavored to meet our responsibilities to the Māori people (indigenous inhabitants of New Zealand) and communities with whom we have researched, as well as meet the requirements and responsibilities of our academic institutions. In this paper, we reflect on the implications of these responsibilities for our work as supervisors of master’s and doctoral students (Māori and non-Māori) who seek to draw on decolonizing methodologies as they undertake research in Māori cultural contexts. We draw on the experiences and interactions we have had with four different postgraduate students whose research on improving educational outcomes for Māori students has required them to engage and participate in Māori cultural contexts.

year: 2017