Learning organisations: A literature review and critique

Approved for Public Release - UnclassifiedA literature review on the Learning Organisation field was conducted, examining the dominant assumptions and creating a solid foundation for the practical application of the learning organisation concept to the Australian Army. In order to examine the literature's dominant assumptions, we asked the following questions: (i) What are the various meanings attributed to learning organisations?; (ii) What sorts of learnings are privileged within the literature?; (iii) What are the key characteristics or "building blocks" that make up a learning organisation? We discovered that the learning organisation construct represents an evolution from bureaucratic and performance-based organisational form to innovative and flexible organisations. In surveying the literature, other factors found to impact on learning organisations included cognitive, social, cultural, technological and structural elements. For example, learning organisations apply increasingly sophisticated understanding of knowledge and personnel management to best exploit their social, intellectual and knowledge capital. In contrast, some factors are not adequately explored in the literature; for example, the significance of power relations, hierarchy and authority on learning within and by organisations has not been fully elucidated. There is an increasing number of studies investigating the direct impact of developing a learner-centric approach on organisational outcomes; the number of studies linking learning to improved organisational performance is growing. There are real, significant and measureable benefits of developing the learning capabilities of an organisation.Steven Talbot, Christina Stothard, Maya Drobnjak and Denise McDowal

Quality evaluation of digital topographic maps

Квалитет просторних података представља скуп њихових карактеристика које одражавају способност просторних података да испуне одређене, унапред формулисане захтеве и/или захтеве који се подразумевају. Сврха описивања квалитета просторних података је да омогући поређење и избор података који најбоље одговара потребама, примени или захтевима корисника. Комплетан опис квалитета једног податка ће подстицати дељење, размену и коришћење одговарајућих скупова просторних података. У овом раду се, на основу теоријских разматрања и спроведеног експеримента, оцењује квалитет дигиталних топографских карата и дефинише оптимална методологија њеног испитивања и оцењивања, која се може применити на целокупан размерни низ дигиталних топографских, прегледнотопографских и географских карата издања Војногеографског института. Поред дефинисања оптималног методолошког поступка за оцену квалитета просторних података дигиталних топографских карата разрађени су облици и обим оцене квалитета у различитим етапама производног процеса израде дигиталних топографских карата. Теоријска разматрања укључују, анализу савремених достигнућа у области контроле квалитета и њене стандардизације, преглед најзачајнијих стандарда дизајнираних за оцену квалитета просторних података дигиталних карата. Дисертацијом се предлаже коришћење методологије, која се заснива на међународном стандарду ISO 19157. Просторни подаци који се израђују у Војногеографском институту (ВГИ), организовани су у Централној Геопросторној бази података. Она представља основу за генерисање свих дигиталних топографских карата целокупног размерног низа топографских карата који се производе у ВГИ-у. Због тога један део дисертације садржи кратак опис модела и организације просторних података у оквиру Централне Геопросторне базе података, где су описани концептуални, логички и физички модели просторних података...The quality of spatial data represent a set of characteristics that reflect to their ability to spatial data to fulfill certain, pre-formulated requirements and/or requirements are considered. The purpose of describing the quality of spatial data is to facilitate the comparison and selection of dataset best suited to application needs or user requirements. A complete description of the data quality shall encourage the sharing, exchange and use of appropriate spatial datasets. This paper, based on theoretical considerations and completing the experiment, analyze the quality of digital topographic maps and define the optimal methodology for its testing and evaluation, which can be applied to the entire range of digital topographic, overview-topographic and geographic maps of Military Geographical Institute. In addition, to defining the optimal methodological procedure for analyzing spatial data quality digital topographic maps were developed forms and scope of the analysis of quality in the various stages of the production process of making digital topographic maps. Theoretical considerations include analysis of contemporary developments in the field of quality control and its standardization, the most significant review of standards designed to analyze the quality of spatial data in digital maps. Dissertation proposes the use of the methodology, which is based on the International standard ISO 19157. Spatial data that are produced in the Military Geographical Institute, organized in Central geospatial database. It is the basis for the generation of digital topographic maps of the entire scale series of topographic maps produced in MGI. Therefore, one chapter of the dissertation contains a brief description of the model and organization of spatial data within the Central Geospatial database, where they described the conceptual, logical and physical models of spatial data..

Oscillations in a maturation model of blood cell production.

We present a mathematical model of blood cell production which describes both the development of cells through the cell cycle, and the maturation of these cells as they differentiate to form the various mature blood cell types. The model differs from earlier similar ones by considering primitive stem cells as a separate population from the differentiating cells, and this formulation removes an apparent inconsistency in these earlier models. Three different controls are included in the model: proliferative control of stem cells, proliferative control of differentiating cells, and peripheral control of stem cell committal rate. It is shown that an increase in sensitivity of these controls can cause oscillations to occur through their interaction with time delays associated with proliferation and differentiation, respectively. We show that the characters of these oscillations are quite distinct and suggest that the model may explain an apparent superposition of fast and slow oscillations which can occur in cyclical neutropenia. © 2006 Society for Industrial and Applied Mathematics

Deformation behavior of two continuously cooled vanadium microalloyed steels at liquid nitrogen temperature

The aim of this work was to establish deformation behaviour of two vanadium microalloyed medium carbon steels with different contents of carbon and titanium by tensile testing at 77 K. Samples were reheated at 1250°C/30 min and continuously cooled at still air. Beside acicular ferrite as dominant morphology in both microstructures, the steel with lower content of carbon and negligible amount of titanium contains considerable fraction of grain boundary ferrite and pearlite. It was found that Ti-free steel exhibits higher strain hardening rate and significantly lower elongation at 77 K than the fully acicular ferrite steel. The difference in tensile behavior at 77 K of the two steels has been associated with the influence of the pearlite, together with higher dislocation density of acicular ferrite. [Projekat Ministarstva nauke Republike Srbije, br. OI174004

Towards a comprehensive framework for movement and distortion correction of diffusion MR images: Within volume movement

Most motion correction methods work by aligning a set of volumes together, or to a volume that represents a reference location. These are based on an implicit assumption that the subject remains motionless during the several seconds it takes to acquire all slices in a volume, and that any movement occurs in the brief moment between acquiring the last slice of one volume and the first slice of the next. This is clearly an approximation that can be more or less good depending on how long it takes to acquire one volume and in how rapidly the subject moves. In this paper we present a method that increases the temporal resolution of the motion correction by modelling movement as a piecewise continous function over time. This intra-volume movement correction is implemented within a previously presented framework that simultaneously estimates distortions, movement and movement-induced signal dropout. We validate the method on highly realistic simulated data containing all of these effects. It is demonstrated that we can estimate the true movement with high accuracy, and that scalar parameters derived from the data, such as fractional anisotropy, are estimated with greater fidelity when data has been corrected for intra-volume movement. Importantly, we also show that the difference in fidelity between data affected by different amounts of movement is much reduced when taking intra-volume movement into account. Additional validation was performed on data from a healthy volunteer scanned when lying still and when performing deliberate movements. We show an increased correspondence between the “still” and the “movement” data when the latter is corrected for intra-volume movement. Finally we demonstrate a big reduction in the telltale signs of intra-volume movement in data acquired on elderly subjects

Why should standard eddy-current distortion correction techniques be avoided even for moderately high b-value data?

This work highlights issues with the current practice for correcting eddy-current distortions on moderately high b-value data and demonstrates their mitigation with a simple alternative. Both techniques are evaluated on real and simulated data, and the importance of EC correction for estimating microstructure is illustrated with the NODDI model. We demonstrate that correcting moderately high b-value data with standard EC correction techniques introduces distortion that compromises the anatomical correspondence between the DWIs and leads to questionable estimates of microstructural features. We show our alternative circumvents these issues and provides good correction

The Role of MRI Physics in Brain Segmentation CNNs: Achieving Acquisition Invariance and Instructive Uncertainties

Being able to adequately process and combine data arising from different sites is crucial in neuroimaging, but is difficult, owing to site, sequence and acquisition-parameter dependent biases. It is important therefore to design algorithms that are not only robust to images of differing contrasts, but also be able to generalise well to unseen ones, with a quantifiable measure of uncertainty. In this paper we demonstrate the efficacy of a physics-informed, uncertainty-aware, segmentation network that employs augmentation-time MR simulations and homogeneous batch feature stratification to achieve acquisition invariance. We show that the proposed approach also accurately extrapolates to out-of-distribution sequence samples, providing well calibrated volumetric bounds on these. We demonstrate a significant improvement in terms of coefficients of variation, backed by uncertainty based volumetric validation

Quantitative assessment of the susceptibility artefact and its interaction with motion in diffusion MRI

In this paper we evaluate the three main methods for correcting the susceptibility-induced artefact in diffusion-weighted magnetic-resonance (DW-MR) data, and assess how correction is affected by the susceptibility field’s interaction with motion. The susceptibility artefact adversely impacts analysis performed on the data and is typically corrected in post-processing. Correction strategies involve either registration to a structural image, the application of an acquired field-map or the use of additional images acquired with different phase-encoding. Unfortunately, the choice of which method to use is made difficult by the absence of any systematic comparisons of them. In this work we quantitatively evaluate these methods, by extending and employing a recently proposed framework that allows for the simulation of realistic DW-MR datasets with artefacts. Our analysis separately evaluates the ability for methods to correct for geometric distortions and to recover lost information in regions of signal compression. In terms of geometric distortions, we find that registration-based methods offer the poorest correction. Field-mapping techniques are better, but are influenced by noise and partial volume effects, whilst multiple phase-encode methods performed best. We use our simulations to validate a popular surrogate metric of correction quality, the comparison of corrected data acquired with AP and LR phase-encoding, and apply this surrogate to real datasets. Furthermore, we demonstrate that failing to account for the interaction of the susceptibility field with head movement leads to increased errors when analysing DW-MR data. None of the commonly used post-processing methods account for this interaction, and we suggest this may be a valuable area for future methods development

Altered patterns of retinoblastoma gene product expression in adult soft-tissue sarcomas.

Altered expression of the retinoblastoma (RB) tumour-suppressor gene product (pRB) has been detected in sporadic bone and soft-tissue sarcomas. Earlier studies, analysing small cohorts of sarcoma patients, have suggested that these alterations are more commonly associated with high-grade tumours, metastatic lesions and poorer survival. This study was designed to re-examine the prevalence and clinical significance of altered pRB expression in a large and selected group of soft-tissue sarcomas from 174 adult patients. Representative tissue sections from these sarcomas were analysed by immunohistochemistry using a well-characterised anti-pRB monoclonal antibody. Tumours were considered to have a positive pRB phenotype only when pure nuclear staining was demonstrated, and cases were segregated into one of three groups. Group 1 (n = 36) were patients whose tumours have minimal or undetectable pRB nuclear staining (< 20% of tumour cells) and were considered pRB negative. Patients with tumours staining in a heterogeneous pattern (20-79% of tumour cells) were classified as group 2 (n = 99). The staining of group 3 (n = 39) was strongly positive with a homogeneous pRB nuclear immunoreactivity (80-100% of tumour cells). pRB alterations were frequently observed in both low- and high-grade lesions. Altered pRB expression did not correlate with known predictors of survival and was not itself an independent predictor of outcome in the long-term follow-up. These findings support earlier observations that alterations of pRB expression are common events in soft-tissue sarcomas; nevertheless, long-term follow-up results indicate that altered patterns of pRB expression do not influence clinical outcome of patients affected with soft-tissue sarcomas. It is postulated that RB alterations are primary events in human sarcomas and may be involved in tumorigenesis or early phases of tumour progression in these neoplasias