A quantum information retrieval approach to memory

As computers approach the physical limits of information storable in memory, new methods will be needed to further improve information storage and retrieval. We propose a quantum inspired vector based approach, which offers a contextually dependent mapping from the subsymbolic to the symbolic representations of information. If implemented computationally, this approach would provide exceptionally high density of information storage, without the traditionally required physical increase in storage capacity. The approach is inspired by the structure of human memory and incorporates elements of Gardenfors’ Conceptual Space approach and Humphreys et al.’s matrix model of memory.

A methodological approach to modelling design led innovation across secondary education : an Australian case study

Incorporating design thinking as a generic capability at a school level is needed to ensure future generations are empowered for business innovation and active citizenship. This paper describes the methodology of an investigation into modelling design led innovation approaches from the business sector to secondary education, as part of a larger study. It builds on a previously discussed research agenda by outlining the scope, significance and limitations of currently available research in this area, examining an action research methodology utilising an Australian design immersion program case study, and discussing implications and future work. It employs a triangulated approach encompassing thematic analysis of qualitative data collection from student focus groups, semi-structured convergent interviews with teachers and facilitators, and student journals. Eventual outcomes will be reviewed and analysed within the framework of a proposed innovation matrix model for educational growth, synthesising principles responding to 21st century student outcomes. It is anticipated this research will inform a successful design led secondary education innovation model, facilitating new engagement frameworks between tertiary and secondary education sectors, as well as providing new insight into the suitability of action research in prototyping social innovation in Australia.

Community interventions for physical activity : the role of a new Cochrane systematic review

Introduction: Systematic reviews are essential in summarising the results of a range of research studies on a specific topic into a single report. They serve as a key source of evidence-based information to support and develop policy and practice for healthy communities. This presentation will examine a new review of community-wide strategies to increase population levels of physical activity and compare it to an earlier Community Guide Review (CGR) of Community-wide campaigns to increase physical activity which recommended community wide interventions. Methods: We registered a Cochrane Systematic Review (CSR) title, published a protocol and recently completed the review of Community-wide interventions to increase physical activity. We compared the definitions, design and findings of the CSR to the CGR. Results: The two reviews differed remarkably in their conclusions with the CGR recommending “strong evidence exists that community-wide campaigns are effective in increasing levels of physical activity”, and the new CSR stating “The body of evidence in this review does not support the hypothesis that multi-component community wide interventions effectively increase population levels of physical activity”. We observed that both reviews examined multi-component interventions as a “combined package”. Possible explanations for the different conclusions may be due to the definition of community (CSR defined community as “comprising those persons residing in a geographically defined community, such as a village, town, or city”, excluding interventions which were whole of state or country, and CGR as “a group of individuals who share one or more characteristics. The CSR utilised a logic model at various stages of the review process and explicitly defined a combination of strategies encompassed within the intervention. The CSR included 25 and CGR 10 studies, respectively. Six of the 10 studies that were included in CGR were excluded from the CSR due to issues relating to study design, intervention definition or duration. The two reviews also differ in function as the CSR seeks to summarise global evidence and included 7 studies in low-income countries, where as the CGR contained only studies deemed relevant to the USA context. Discussion: Differences in the findings between older and newer reviews can be due to a variety of factors. For example, in updating a review the definition of an intervention can be changed. Further, differences may also be due to improvements in the standards and methodologies for systematic reviews as well as the inclusion of newer studies. These factors need to be understood whenever differences between newer and older reviews are considered.

Subpopulation triage: How to allocate conservation effort among populations

Threatened species often exist in a small number of isolated subpopulations. Given limitations on conservation spending, managers must choose from strategies that range from managing just one subpopulation and risking all other subpopulations to managing all subpopulations equally and poorly, thereby risking the loss of all subpopulations. We took an economic approach to this problem in an effort to discover a simple rule of thumb for optimally allocating conservation effort among subpopulations. This rule was derived by maximizing the expected number of extant subpopulations remaining given n subpopulations are actually managed. We also derived a spatiotemporally optimized strategy through stochastic dynamic programming. The rule of thumb suggested that more subpopulations should be managed if the budget increases or if the cost of reducing local extinction probabilities decreases. The rule performed well against the exact optimal strategy that was the result of the stochastic dynamic program and much better than other simple strategies (e.g., always manage one extant subpopulation or half of the remaining subpopulation). We applied our approach to the allocation of funds in 2 contrasting case studies: reduction of poaching of Sumatran tigers (Panthera tigris sumatrae) and habitat acquisition for San Joaquin kit foxes (Vulpes macrotis mutica). For our estimated annual budget for Sumatran tiger management, the mean time to extinction was about 32 years. For our estimated annual management budget for kit foxes in the San Joaquin Valley, the mean time to extinction was approximately 24 years. Our framework allows managers to deal with the important question of how to allocate scarce conservation resources among subpopulations of any threatened species. © 2008 Society for Conservation Biology.

Heritability analysis of surface-based cortical thickness estimation on a large twin cohort

The aim of this paper is to assess the heritability of cerebral cortex, based on measurements of grey matter (GM) thickness derived from structural MR images (sMRI). With data acquired from a large twin cohort (328 subjects), an automated method was used to estimate the cortical thickness, and EM-ICP surface registration algorithm was used to establish the correspondence of cortex across the population. An ACE model was then employed to compute the heritability of cortical thickness. Heritable cortical thickness measures various cortical regions, especially in frontal and parietal lobes, such as bilateral postcentral gyri, superior occipital gyri, superior parietal gyri, precuneus, the orbital part of the right frontal gyrus, right medial superior frontal gyrus, right middle occipital gyrus, right paracentral lobule, left precentral gyrus, and left dorsolateral superior frontal gyrus.

An efficient algorithm for linear programming

A simple but efficient algorithm is presented for linear programming. The algorithm computes the projection matrix exactly once throughout the computation unlike that of Karmarkar’s algorithm where in the projection matrix is computed at each and every iteration. The algorithm is best suitable to be implemented on a parallel architecture. Complexity of the algorithm is being studied.

Assessment of cobia, Rachycentron canadum, in the waters of the U.S. Gulf of Mexico

This assessment applies to cobia (Rachycentron canadum) located in the territorial waters of the U.S. Gulf of Mexico. Separation of the Gulf of Mexico and Atlantic Ocean is defined by the seaward extension of the Dade/Monroe county line in south Florida. Mixing of fish between the Atlantic and Gulf of Mexico occurs in the Florida Keys during winter months. Cobia annually migrate north in early spring in the Gulf to spawning grounds in the northern Gulf of Mexico, returning to the Florida Keys by winter. Catches of cobia in the Gulf of Mexico are dominated by recreational landings, accounting for nearly 90% of the total. Since 1980, the landings of cobia in the recreational fishery have remained fairly stable at around 400-600 mt with a slight peak of 1,014 mt in 1997. The recreational fishery was estimated to have landed 471 mt in 2000. The landings from the commercial fishery have shown a steady increase from 45 mt in 1980 to a peak of 120 mt in 1994, followed by a decline to 62 mt in 2000. The previous assessment of cobia occurred in 1996 using a virtual population analysis (VPA) model. For this analysis a surplus-production model (ASPIC) and a forward-projecting, age-structured population model programmed in the AD Model Builder (ADMB) software were applied to cobia data from the Gulf of Mexico. The primary data consisted of four catch-per-unit-effort (CPUE) indices derived from the Marine Recreational Fisheries Statistics Survey (MRFSS) (1981-1999), Southeast region headboat survey (1986-1999), Texas creel survey (1983-1999), and shrimp bycatch estimates (1980-1999). Length samples were available from the commercial (1983-2000) and recreational (1981-2000) fisheries. The ASPIC model applied to the cobia data provided unsatisfactory results. The ADMB model fit described the observed length composition data and fishery landings fairly well based on graphical examination of model residuals. The CPUE indices indicated some disagreement for various years, but the model fit an overall increasing trend from 1992-1997 for the MRFSS, headboat, and Texas creel indices. The shrimp bycatch CPUE was treated as a recruitment index in the model. The fit to these data followed an upward trend in recruitment from 1988-1997, but did not fit the 1994-1997 data points very well. This was likely the result of conflicting information from other data sources. Natural mortality (M) for cobia is unknown. As a result, a range of values for M from 0.2-0.4, based on longevity and growth parameters, were selected for use in the age-structured model. The choice of natural mortality appears to greatly influence the perceived status of the population. Population status as measured by spawning stock biomass in the last year relative to the value at maximum sustainable yield (SSB2000/SSBMSY), spawning stock biomass in the last year relative to virgin spawning stock biomass (SSB2000/S0), and static spawning stock biomass per recruit (SSBR) all indicate the population is either depleted, near MSY, or well above MSY depending on the choice of M. The variance estimates for these benchmarks are very large and in most cases ranges from depleted to very healthy status. The only statement that can be made with any degree of certainty about cobia in the Gulf of Mexico is that the population has increased since the 1980s. (PDF contains 61 pages)

Panama City Fisheries Resources Office: FY 2008 Annual Report

HIGHLIGHTS FOR FY 2008 1. Completed the first of a two-year Gulf sturgeon population study on the Choctawhatchee River, Florida. The sub adult and adult Gulf sturgeon population was estimated at 2,800 fish. 2. Gulf sturgeon eggs were collected at three hard bottom sites in the Apalachicola River, Florida; two sites were previously confirmed spawning areas and one was a newly confirmed spawning area. 3. Documented 55 potential environmental threats to Gulf sturgeon spawning habitat in the Pea River, Florida and Alabama. 4. Assigned the Eglin AFB Road-Stream Crossing Working Group to guide the closure, repair and maintenance of roads and road stream crossings that impact threatened and endangered species. 5. Conducted 81 assessments of fish and stream invertebrates on and in watersheds surrounding Eglin AFB. 6. Provided technical support for the 5-year status review and reclassification proposed rule for the Okaloosa darter. 7. Initiated an intensive population genetic analysis of the Okaloosa darter throughout its range. Tissues from over 200 Okaloosa darters were collected and analyzed. 8. Established a GIS database to serve as a host for data from any sites sampled for mussels in Northeast Gulf of Mexico drainages. 9. Conducted habitat surveys at 115 locations in the Apalachicola River to assess the effects of drought-related mussel mortality and strandings, evaluate habitat conditions, and assess population demography. 10. A land use/aerial imagery threats assessment data analysis was completed for the Chipola River. A total of 266 impoundments/borrow pits and 471 unpaved road crossings were identified among the threats. 11. Okaloosa darters marked with elastomeric dyes were monitored in Mill Creek, Eglin AFB, to determine movement and habitat use following completion of a fish passage project. 3 12. Partners for Fish and Wildlife funded a streambank and riparian restoration project on Econfina Creek consisting of 3,900 feet of streambank fencing to exclude cattle access. One acre of riparian floodplain was planted with native trees. 13. We provided design and on-the-ground assistance for restoring surface hydrology at St. Vincent NWR. The project restored approximately 1.5 miles of tidal stream and 100 acres of wetlands. 14. A study was completed on 11 coastal streams to document large wood debris relationships with fluvial geomorphic characteristics. 15. We developed a Population Viability Analysis model for the fat threeridge mussel to determine current and future risk of extinction. 17. A Gulf Sturgeon Friends Group, “Gulf Sturgeon Preservation Society” was organized in FY 08. 18. Multiple outreach projects were completed to detail aquatic resource conservation needs and opportunities, including National Fishing Week, Earth Day, several festivals and school outreach.

Fabrication of silicon-on-reflector for Si-based resonant-cavity-enhanced photodetectors

A novel silicon-on-reflector substrate for Si-based resonant-cavity-enhanced photodetectors has been fabricated by using Si-based sol-gel and smart-cut techniques. The Si/SiO2 Bragg reflector is controlled in situ by electron beam evaporation and the thickness can be adjusted to get high reflectivity. The reflectance spectra of the silicon-on-reflector substrate with five pairs of Si/SiO2 reflector have been measured and simulated by transfer matrix model. The reflectivity at operating wavelength is close to 100%. Based on the silicon-on-reflector substrate, SiGe/Si multiple quantum wells resonant-cavity-enhanced photodetectors for 1.3 mu m wavelength have been designed and simulated. Ten-fold enhancement of the quantum efficiency of resonant-cavity-enhanced photodetectors compared with conventional photodetectors is predicted.

一种基于投影矩阵M的机器人手眼标定线性化方法

提出了一种基于投影矩阵M的机器人手眼标定方法,即将AX=XB转换为MY=M′YB求解形式,避免了矩阵分解.同时,采用矩阵直积运算和矩阵特征向量运算相结合的方法,将传统的非线性问题转换成线性问题,构成了可利用最小二乘法求解运算的解析形式,提高了机器人手眼标定的精度和稳定性.通过实验验证了该方法的可行性.

一种基于线性模型的机器人手眼标定新方法

针对基于传统手眼标定模型AX=XB的标定问题,引入了由摄像机投影矩阵M构成的数学模型MY=M'YB,并针对该模型提出了一种新解法。该方法运用矩阵直积和特征向量理论,将关于机器人手眼关系矩阵X的问题描述转换成关于关联矩阵Y的线性方程,运用最小二乘法求得线性闭解。该方法消除了传统方法多次分解摄像机传感器系统的内外参数而引入的摄像机传感器系统的固有误差和随机误差的影响。实验表明该方法可以提高手眼系统标定精度。

统计不相关最佳鉴别矢量集的本质研究

对统计不相关最佳鉴别矢量集的本质进行研究 ,在基于总体散布矩阵特征分解的基础上 ,构造了一种白化变换 ,使得变换后的样本空间中的总体散布矩阵为单位矩阵 ,这样使得传统的最佳鉴别矢量集算法得到的均是具有统计不相关的最佳鉴别矢量集 ,从而揭示了统计不相关最佳鉴别变换的本质———白化变换加普通的线性鉴别变换。该方法的最大优点在于所获得的最优鉴别矢量同时具有正交性和统计不相关性。该方法对代数特征抽取具有普遍适用性。用ORL人脸数据库的数值实验 ,验证了该方法的有效性

一种新的图像特征抽取方法研究

对最佳鉴别矢量的求解方法进行了研究，根据矩阵的分块理论和优化理论，在一定的条件下，从理论上得到类间散布矩阵和总体散布矩阵的一种简洁表示方法，提出了求解最佳鉴别矢量的一种新算法，该算法的优点是计算量明显减少。ORL人脸数据库的数值实验，验证了上述论断的正确性。实验结果表明，虽然识别率与分块维数之间存在非线性关系，但可以通过选择适当的分块维数来获得较高的识别率。类间散布矩阵和总体散布矩阵的一种简洁表示方法适合于一切使用Fisher鉴别准则的模式识别问题。

Propagation of the degree of polarisation in a few-mode optical fibre: Experimental results

R. Zwiggelaar and M.G.F. Wilson, 'Propagation of the degree of polarisation in a few-mode optical fibre: Experimental results', International Journal of Optoelectronics 10 (4), 295-297 (1996)

Communications inspired linear discriminant analysis

We study the problem of supervised linear dimensionality reduction, taking an information-theoretic viewpoint. The linear projection matrix is designed by maximizing the mutual information between the projected signal and the class label. By harnessing a recent theoretical result on the gradient of mutual information, the above optimization problem can be solved directly using gradient descent, without requiring simplification of the objective function. Theoretical analysis and empirical comparison are made between the proposed method and two closely related methods, and comparisons are also made with a method in which Rényi entropy is used to define the mutual information (in this case the gradient may be computed simply, under a special parameter setting). Relative to these alternative approaches, the proposed method achieves promising results on real datasets. Copyright 2012 by the author(s)/owner(s).