title: Using the online cross-entropy method to learn relational policies for playing different games

authors: Sarjant, Samuel

subjects: computer science

abstract: By defining a video-game environment as a collection of objects, relations, actions and rewards, the relational reinforcement learning algorithm presented in this paper generates and optimises a set of concise, human-readable relational rules for achieving maximal reward. Rule learning is achieved using a combination of incremental specialisation of rules and a modified online cross-entropy method, which dynamically adjusts the rate of learning as the agent progresses. The algorithm is tested on the Ms. Pac-Man and Mario environments, with results indicating the agent learns an effective policy for acting within each environment.

text: Using the online cross-entropy method to learn relational policies for playing different games By defining a video-game environment as a collection of objects, relations, actions and rewards, the relational reinforcement learning algorithm presented in this paper generates and optimises a set of concise, human-readable relational rules for achieving maximal reward. Rule learning is achieved using a combination of incremental specialisation of rules and a modified online cross-entropy method, which dynamically adjusts the rate of learning as the agent progresses. The algorithm is tested on the Ms. Pac-Man and Mario environments, with results indicating the agent learns an effective policy for acting within each environment.

year: 2011

title: Changes in carbon and nitrogen stocks following conversion of plantation forest to dairy pasture on pumice soils, in the Central North Island

authors: Lewis, Riki Windsor

subjects: Carbon

abstract: Since 1990 approximately 36,000 ha of land in the Waikato has been converted from pine plantation to dairy farms. By changing land use from plantation forest to pasture there is potential to change soil properties. The property of interest, due to international discussion (Kyoto Protocol), is the potential for soils to store carbon. My main objective was to determine the rate and magnitude of change in soil carbon, soil nitrogen, and C:N ratio following land conversion from pine plantation to pasture. My study examined three areas (Atiamuri, Tokoroa and Wairakei) in the Central North Island of New Zealand. At each study area sites ranging from pine plantation, through 2, 3, 4, 5 and 11 years since conversion, to long-term (>40 years) dairy or sheep/beef pasture, were identified. Three transects were established at each site and 7 soil core samples each to a depth of 60 cm, were taken at random intervals along each transect. Soil cores were split into horizons with samples from each horizon bulked together for each transect. At the midpoint of each transect a pit was dug and soil dry bulk density samples were taken from each horizon. At one pit from each site a sample of each soil horizon was taken. In the laboratory all soil samples were passed through a 2 mm sieve and air dried. Air dried samples were crushed and analysed for total carbon and total nitrogen with a TruSpec CN Carbon/Nitrogen Determinator. Soil dry bulk density was lower (P<0.05) in the pine sites Ap horizons (0.47 to 0.54 g cm-3) than the Ap horizon for all other sites (0.59 to 0.76 g cm-3) at the Atiamuri, Tokoroa and Wairakei areas. There was no significant difference in Ap horizon depths between pine forest, recent conversion and long-term pasture sites at any of the study areas. Carbon concentration in the Ap horizon (5.5 to 9 %) showed few significant differences between land-use sites. The total soil carbon at Atiamuri and Wairakei was higher (P<0.05) in the long-term pastures (88 to 100 t/ha) than in the pine (42 to 54 t/ha), however there was no significant difference between pine and long-term pasture at Tokoroa and data from recently converted sites were variable with no apparent significant differences. Total soil nitrogen at all three study areas was higher (P<0.05) in the long-term pasture sites (5 to 8 t/ha) than in the pine sites (9 to 12 t/ha). The C:N ratio in the Ap horizon was higher (P<0.05) in pine sites (mean of 16) than in the long-term pasture sites (mean of 10). The variability in the recently converted sites meant that generally no short-term changes in carbon, nitrogen or C:N ratio, following conversion from pine forest to dairy pasture were discernable.

text: Changes in carbon and nitrogen stocks following conversion of plantation forest to dairy pasture on pumice soils, in the Central North Island Since 1990 approximately 36,000 ha of land in the Waikato has been converted from pine plantation to dairy farms. By changing land use from plantation forest to pasture there is potential to change soil properties. The property of interest, due to international discussion (Kyoto Protocol), is the potential for soils to store carbon. My main objective was to determine the rate and magnitude of change in soil carbon, soil nitrogen, and C:N ratio following land conversion from pine plantation to pasture. My study examined three areas (Atiamuri, Tokoroa and Wairakei) in the Central North Island of New Zealand. At each study area sites ranging from pine plantation, through 2, 3, 4, 5 and 11 years since conversion, to long-term (>40 years) dairy or sheep/beef pasture, were identified. Three transects were established at each site and 7 soil core samples each to a depth of 60 cm, were taken at random intervals along each transect. Soil cores were split into horizons with samples from each horizon bulked together for each transect. At the midpoint of each transect a pit was dug and soil dry bulk density samples were taken from each horizon. At one pit from each site a sample of each soil horizon was taken. In the laboratory all soil samples were passed through a 2 mm sieve and air dried. Air dried samples were crushed and analysed for total carbon and total nitrogen with a TruSpec CN Carbon/Nitrogen Determinator. Soil dry bulk density was lower (P<0.05) in the pine sites Ap horizons (0.47 to 0.54 g cm-3) than the Ap horizon for all other sites (0.59 to 0.76 g cm-3) at the Atiamuri, Tokoroa and Wairakei areas. There was no significant difference in Ap horizon depths between pine forest, recent conversion and long-term pasture sites at any of the study areas. Carbon concentration in the Ap horizon (5.5 to 9 %) showed few significant differences between land-use sites. The total soil carbon at Atiamuri and Wairakei was higher (P<0.05) in the long-term pastures (88 to 100 t/ha) than in the pine (42 to 54 t/ha), however there was no significant difference between pine and long-term pasture at Tokoroa and data from recently converted sites were variable with no apparent significant differences. Total soil nitrogen at all three study areas was higher (P<0.05) in the long-term pasture sites (5 to 8 t/ha) than in the pine sites (9 to 12 t/ha). The C:N ratio in the Ap horizon was higher (P<0.05) in pine sites (mean of 16) than in the long-term pasture sites (mean of 10). The variability in the recently converted sites meant that generally no short-term changes in carbon, nitrogen or C:N ratio, following conversion from pine forest to dairy pasture were discernable.

year: 2011

title: A Pilot investigation into the assessment of changes in the psycholinguistic abilities of new-entrant Māori school children using the Illinois Test of Psycholinguistic Abilities

authors: St George, William Vivian Ross

abstract: The role of language as the principal medium of instruction within the New Zealand (N .Z.) educational system has recently received increasing attention both from researchers and those responsible for the formulation of our national educational policy. In particular, much attention has been directed toward the Maori pupil and the use of the English language as the medium for his instruction. The range of literature on this question includes controlled research studies on English usage by Maori children, educational policy statements concerning the - medium of instruction to be employed in New Zealand schools and writings of a more speculative, and potentially political nature, questioning educational policy and the role of language in "Maori education".

text: A Pilot investigation into the assessment of changes in the psycholinguistic abilities of new-entrant Māori school children using the Illinois Test of Psycholinguistic Abilities The role of language as the principal medium of instruction within the New Zealand (N .Z.) educational system has recently received increasing attention both from researchers and those responsible for the formulation of our national educational policy. In particular, much attention has been directed toward the Maori pupil and the use of the English language as the medium for his instruction. The range of literature on this question includes controlled research studies on English usage by Maori children, educational policy statements concerning the - medium of instruction to be employed in New Zealand schools and writings of a more speculative, and potentially political nature, questioning educational policy and the role of language in "Maori education".

year: 1969