title: Online Isolation Forest

authors: Leveni, F

abstract: The anomaly detection literature is abundant with offline methods, which require repeated access to data in memory, and impose impractical assumptions when applied to a streaming context. Existing online anomaly detection methods also generally fail to address these constraints, resorting to periodic retraining to adapt to the online context. We propose ONLINE-IFOREST, a novel method explicitly designed for streaming conditions that seamlessly tracks the data generating process as it evolves over time. Experimental validation on real-world datasets demonstrated that ONLINE-IFOREST is on par with online alternatives and closely rivals state-of-the-art offline anomaly detection techniques that undergo periodic retraining. Notably, ONLINE-IFOREST consistently outperforms all competitors in terms of efficiency, making it a promising solution in applications where fast identification of anomalies is of primary importance such as cybersecurity, fraud and fault detection.

text: Online Isolation Forest The anomaly detection literature is abundant with offline methods, which require repeated access to data in memory, and impose impractical assumptions when applied to a streaming context. Existing online anomaly detection methods also generally fail to address these constraints, resorting to periodic retraining to adapt to the online context. We propose ONLINE-IFOREST, a novel method explicitly designed for streaming conditions that seamlessly tracks the data generating process as it evolves over time. Experimental validation on real-world datasets demonstrated that ONLINE-IFOREST is on par with online alternatives and closely rivals state-of-the-art offline anomaly detection techniques that undergo periodic retraining. Notably, ONLINE-IFOREST consistently outperforms all competitors in terms of efficiency, making it a promising solution in applications where fast identification of anomalies is of primary importance such as cybersecurity, fraud and fault detection.

year: 2024

title: Microstructure and thermal stability of nanostructured Cu-7.5vol.%Al₂O₃ composite powders produced by high energy mechanical milling

authors: Mukhtar, Aamir

subjects: engineering

abstract: Nanostructured Cu-7.5vol.%Al₂O₃ composite powders were produced from a mixture of Cu powder and Al₂O₃  nanopowder using two routes of high energy mechanical milling. The milled composite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the microstructure and corresponding micohardness change of the powder particles as a function of the annealing temperature. For the nanocomposite powder produced with 12 hours of milling (Route 1), heat treatment at 150°C did not change the microstructure, increasing the annealing temperature from 150 to 500°C caused the Cu grain sizes to increase due to grain coarsening. For the composite powder produced with 24 hours milling (Route 2), the grain sizes of the Cu matrix also increased due to grain coarsening with increasing the annealing temperature from 150 to 500°C. Average microhardness decreased significantly for both the nanocomposite powders but the degree of grain size increase was smaller with increasing the annealing temperature from 400 to 500°C.

text: Microstructure and thermal stability of nanostructured Cu-7.5vol.%Al₂O₃ composite powders produced by high energy mechanical milling Nanostructured Cu-7.5vol.%Al₂O₃ composite powders were produced from a mixture of Cu powder and Al₂O₃  nanopowder using two routes of high energy mechanical milling. The milled composite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the microstructure and corresponding micohardness change of the powder particles as a function of the annealing temperature. For the nanocomposite powder produced with 12 hours of milling (Route 1), heat treatment at 150°C did not change the microstructure, increasing the annealing temperature from 150 to 500°C caused the Cu grain sizes to increase due to grain coarsening. For the composite powder produced with 24 hours milling (Route 2), the grain sizes of the Cu matrix also increased due to grain coarsening with increasing the annealing temperature from 150 to 500°C. Average microhardness decreased significantly for both the nanocomposite powders but the degree of grain size increase was smaller with increasing the annealing temperature from 400 to 500°C.

year: 2009

title: Visualising Mātauranga Māori for iwi outcomes

authors: Hudson, Maui

subjects: Mätauranga Mäori

abstract: Ko te Mätauranga Mäori he puna nö te katoa, he mea äta whakatipu hoki e ngä whänau, e ngä hapü, e ngä iwi hoki o tënä, o tënä o ngä whakareanga maha. He mätauranga nö te hapori, he mea äta whakatö hoki ki roto i ngä wheako o te ia rä, he mea kawe ki te pürakau, ki te waiata, ki ngä karangahanga whenua, ki te kani, ki te kawa, ki te whakapapa, ki te pümahara, ki te whakakitenga, ki te matakite, ki te whakaakoranga me te tohu pütake, hei tirohanga, ka mutu he mea äta ako mä te tirohanga, mä tängata kë atu ränei o te hapori. Tënei mea te Mätauranga Mäori, he pünaha whakatipu möhiohio, he nukurau, he nanakia anö hoki, kua hangä mai ki te mätauranga ä-whänau, ä-hapü, ä-iwi anö hoki.
Kei te whakatau tikanga, kei te whakamahere, kei te whakamahi hoki ëtahi hunga tangata i te Mätauranga Mäori, ka mutu kei tënä öna anö whaihuatanga. Ko te aho e whakakotahi nei i ngä röpü käwanatanga me ngä kaunihera ä-rohe, ko te whakaaro e hängai pü ana te mätauranga Mäori ki te Mäori, he mea whakahängai hoki, ka mutu he rerekë i tënä, i tënä o ngä rohe. Ki tä te nuinga o ngä hunga tangata, ko te whakapakarihia o ö rätou ake märamatanga ki te mätauranga Mäori tëtahi tino whäinga ä-rautaki, kei reira hoki he äwhina i te ärahi whakataunga, i te whakahaerenga, i te tikanga mätai anö hoki, me te takoha atu ki te nanakia e taea nei e te mätauranga Mäori, kia waihangatia mai ai he tatauranga tika mä tënei whakareanga.
He maha ngä kauwaka e kawe atu nei i tënei mea i te Mätauranga Mäori. E körero nei ngä mana whenua i ö rätou hiahia ki te whakamahinga o ngä taputapu wähi ä-nuku hei whakakitenga atu i te mätauranga Mäori i te taha o te raraunga pütaiao, kia tautokohia ai ngä whakataunga ki ngä hua ä-taiao nei. I tënei pepa, ka körerohia e mätou ko Takiwa, koia he Geo-spatial Visualisation Tool e whakatakoto nei i te papa whakatü mö Takiwa Lakes, e hängai nei ki ngä kaupapa wähi ä-nuku e toru. Kua whai hononga te taputapu ki ëtahi kaitiaki, e tika ai te horopaki, ngä kiko, me te whakahaere o te mätauranga Mäori i töna papa whakatü. He tino take ënei i tënei wä e aro pü nei ngä ohu tangata kia nui ake te whakamahinga o te mätauranga Mäori i ngä whakataunga. Ko te whäinga o ngä hononga kaitiaki ko te whakatinana ake i ngä mahere whakahaere mä roto anö i te whakamatihiko i ngä raraunga me ngä körero i ngä mahere, me te whakaatu i ërä i te taha o ngä raraunga pütaiao. E whakamana nei tënei papa whakatü i ngä mana whenua mä roto i te whakaatu i ngä tohunga pütaiao pënei me te kounga, te nui ränei o te wai (te wäwahi ränei) i roto i te horopaki o te raraunga mätauranga Mäori, pënei anö me ngä whenua hirahira ki te Mäori me ngä mahinga kai. Heoi, he take whakatü pihi te whakamahinga o te mätauranga Mäori i ëtahi wä, nö reira me whai whakaaro ki te whakangungu i te mana, i te tüturu, i te ngäkau tapatahi ä-ahurea nei anö hoki o ngä hapori ka whai wähi mai.
Mätauranga Mäori is the shared intellectual capital generated by whänau, hapü and iwi over multiple generations. It is community knowledge embedded in lived experience and carried in stories, song, place names, dance, ceremonies, genealogies, memories, visions, prophesies, teachings and original instructions, as learnt through observation and via other community members. Mätauranga Mäori is a dynamic, innovative, and generative system of knowledge constituted from mätauranga ä-whänau, mätauranga ä-hapü, and mätauranga ä-iwi.
Mätauranga Mäori is being defined, framed, and operationalised with varying success by a range of institutions. The general premise is that government agencies and regional councils acknowledge mätauranga Mäori as Mäori-specific knowledge that is adaptive and regionally distinct. For most institutions, improving their understanding of mätauranga Mäori is an important strategic aim that can help guide their decision-making, management, and monitoring procedures as well as contribute to the innovative potential of Mäori knowledge in order to create culturally appropriate data for this generation.
Mätauranga Mäori is transmitted through a number of mediums. Mana whenua are expressing interest in how geospatial tools can visualise mätauranga Mäori alongside science data to support decision-making for environmental outcomes. In this paper we discuss Takiwa, a geospatial visualisation tool that provides the platform for Takiwa Lakes, in relation to three geospatial initiatives. This tool has developed kaitiaki layers to provide an appropriate context, content and control of mätauranga Mäori within its platform. These are critical factors as agencies focus on increasing the use of mätauranga Mäori for decision-making. The aim of the kaitiaki layers is to bring iwi management plans to life by digitising the data and information within the plans and presenting them alongside scientific data. This platform empowers mana whenua by presenting scientific indicators such as water quality and quantity (e.g. allocation) within the context of mätauranga Mäori data such as sites of cultural significance and mahinga kai. However, the use of mätauranga Mäori can be a sensitive issue and it is important that consideration is given to protecting the cultural authority, cultural authenticity, and cultural integrity of the participating communities.

text: Visualising Mātauranga Māori for iwi outcomes Ko te Mätauranga Mäori he puna nö te katoa, he mea äta whakatipu hoki e ngä whänau, e ngä hapü, e ngä iwi hoki o tënä, o tënä o ngä whakareanga maha. He mätauranga nö te hapori, he mea äta whakatö hoki ki roto i ngä wheako o te ia rä, he mea kawe ki te pürakau, ki te waiata, ki ngä karangahanga whenua, ki te kani, ki te kawa, ki te whakapapa, ki te pümahara, ki te whakakitenga, ki te matakite, ki te whakaakoranga me te tohu pütake, hei tirohanga, ka mutu he mea äta ako mä te tirohanga, mä tängata kë atu ränei o te hapori. Tënei mea te Mätauranga Mäori, he pünaha whakatipu möhiohio, he nukurau, he nanakia anö hoki, kua hangä mai ki te mätauranga ä-whänau, ä-hapü, ä-iwi anö hoki.
Kei te whakatau tikanga, kei te whakamahere, kei te whakamahi hoki ëtahi hunga tangata i te Mätauranga Mäori, ka mutu kei tënä öna anö whaihuatanga. Ko te aho e whakakotahi nei i ngä röpü käwanatanga me ngä kaunihera ä-rohe, ko te whakaaro e hängai pü ana te mätauranga Mäori ki te Mäori, he mea whakahängai hoki, ka mutu he rerekë i tënä, i tënä o ngä rohe. Ki tä te nuinga o ngä hunga tangata, ko te whakapakarihia o ö rätou ake märamatanga ki te mätauranga Mäori tëtahi tino whäinga ä-rautaki, kei reira hoki he äwhina i te ärahi whakataunga, i te whakahaerenga, i te tikanga mätai anö hoki, me te takoha atu ki te nanakia e taea nei e te mätauranga Mäori, kia waihangatia mai ai he tatauranga tika mä tënei whakareanga.
He maha ngä kauwaka e kawe atu nei i tënei mea i te Mätauranga Mäori. E körero nei ngä mana whenua i ö rätou hiahia ki te whakamahinga o ngä taputapu wähi ä-nuku hei whakakitenga atu i te mätauranga Mäori i te taha o te raraunga pütaiao, kia tautokohia ai ngä whakataunga ki ngä hua ä-taiao nei. I tënei pepa, ka körerohia e mätou ko Takiwa, koia he Geo-spatial Visualisation Tool e whakatakoto nei i te papa whakatü mö Takiwa Lakes, e hängai nei ki ngä kaupapa wähi ä-nuku e toru. Kua whai hononga te taputapu ki ëtahi kaitiaki, e tika ai te horopaki, ngä kiko, me te whakahaere o te mätauranga Mäori i töna papa whakatü. He tino take ënei i tënei wä e aro pü nei ngä ohu tangata kia nui ake te whakamahinga o te mätauranga Mäori i ngä whakataunga. Ko te whäinga o ngä hononga kaitiaki ko te whakatinana ake i ngä mahere whakahaere mä roto anö i te whakamatihiko i ngä raraunga me ngä körero i ngä mahere, me te whakaatu i ërä i te taha o ngä raraunga pütaiao. E whakamana nei tënei papa whakatü i ngä mana whenua mä roto i te whakaatu i ngä tohunga pütaiao pënei me te kounga, te nui ränei o te wai (te wäwahi ränei) i roto i te horopaki o te raraunga mätauranga Mäori, pënei anö me ngä whenua hirahira ki te Mäori me ngä mahinga kai. Heoi, he take whakatü pihi te whakamahinga o te mätauranga Mäori i ëtahi wä, nö reira me whai whakaaro ki te whakangungu i te mana, i te tüturu, i te ngäkau tapatahi ä-ahurea nei anö hoki o ngä hapori ka whai wähi mai.
Mätauranga Mäori is the shared intellectual capital generated by whänau, hapü and iwi over multiple generations. It is community knowledge embedded in lived experience and carried in stories, song, place names, dance, ceremonies, genealogies, memories, visions, prophesies, teachings and original instructions, as learnt through observation and via other community members. Mätauranga Mäori is a dynamic, innovative, and generative system of knowledge constituted from mätauranga ä-whänau, mätauranga ä-hapü, and mätauranga ä-iwi.
Mätauranga Mäori is being defined, framed, and operationalised with varying success by a range of institutions. The general premise is that government agencies and regional councils acknowledge mätauranga Mäori as Mäori-specific knowledge that is adaptive and regionally distinct. For most institutions, improving their understanding of mätauranga Mäori is an important strategic aim that can help guide their decision-making, management, and monitoring procedures as well as contribute to the innovative potential of Mäori knowledge in order to create culturally appropriate data for this generation.
Mätauranga Mäori is transmitted through a number of mediums. Mana whenua are expressing interest in how geospatial tools can visualise mätauranga Mäori alongside science data to support decision-making for environmental outcomes. In this paper we discuss Takiwa, a geospatial visualisation tool that provides the platform for Takiwa Lakes, in relation to three geospatial initiatives. This tool has developed kaitiaki layers to provide an appropriate context, content and control of mätauranga Mäori within its platform. These are critical factors as agencies focus on increasing the use of mätauranga Mäori for decision-making. The aim of the kaitiaki layers is to bring iwi management plans to life by digitising the data and information within the plans and presenting them alongside scientific data. This platform empowers mana whenua by presenting scientific indicators such as water quality and quantity (e.g. allocation) within the context of mätauranga Mäori data such as sites of cultural significance and mahinga kai. However, the use of mätauranga Mäori can be a sensitive issue and it is important that consideration is given to protecting the cultural authority, cultural authenticity, and cultural integrity of the participating communities.

year: 2020