38 resultados para complexity in spatiotemporal evolution
Resumo:
This research considers information systems development (ISD) projects as complex adaptive systems. We investigate the question whether complex adaptive systems (CAS) theory is relevant as a theoretical foundation for understanding ISD, and if so, which kind of understanding can be achieved by utilizing the theory? We introduce key concepts of CAS theory such as interaction, emergence, interconnected autonomous agents, selforganization, co-evolution, poise at the edge of chaos, time pacing, and poise at the edge of time to analyse and understand ISD in practice. We demonstrate the strength of such a CAS approach through an empirical case study presentation and analysis. While our work contributes to a complexity theory of ISD, the case examination also provides practical advice derived from this perspective to successfully cope with complexity in ISD in an adaptive manner.
Resumo:
This paper considers GSD projects as designed artefacts, and proposes the application of an Extended Axiomatic Design theory to reduce their complexity in order to increase the probability of project success. Using an upper bound estimation of the Kolmogorov complexity of the so-called ‘design matrix’ (as a proxy of Information Content as a complexity measure) we demonstrate on two hypothetical examples how good and bad designs of GSD planning compare in terms of complexity. We also demonstrate how to measure and calculate the ‘structural’ complexity of GSD projects and show that by satisfying all design axioms this ‘structural’ complexity could be minimised.
Resumo:
Liquid chromatography–mass spectrometry (LC–MS) methods using either aqueous normal phase (ANP) or reversed phase (RP) columns are routinely used in small molecule or metabolomic analyses. These stationary phases enable chromatographic fractionation of polar and non-polar compounds, respectively. The application of a single chromatographic stationary phase to a complex biological extract results in a significant proportion of compounds which elute in the non-retained fraction, where they are poorly detected because of a combination of ion suppression and the co-elution of isomeric compounds. Thus coverage of both polar and non-polar components of the metabolome generally involves multiple analyses of the same sample, increasing the analysis time and complexity. In this study we describe a novel tandem in-line LC–MS method, in which compounds from one injection are sequentially separated in a single run on both ANP and RP LC-columns. This method is simple, robust, and enables the use of independent gradients customized for both RP and ANP columns. The MS signal is acquired in a single chromatogram which reduces instrument time and operator and data analysis errors. This method has been used to analyze a range of biological extracts, from plant and animal tissues, human serum and urine, microbial cell and culture supernatants. Optimized sample preparation protocols are described for this method as well as a library containing the retention times and accurate masses of 127 compounds.
Resumo:
Surface passivation of AZNd Mg alloy with Pr(NO3)3 is studied using scanning electrochemical microscopy (SECM) in surface generation/tip collection (SG/TC) and AC modes. Corrosion protection afforded by the Pr treatment and the degradation mechanism in a simulated biological environment was examined on a local scale and compared with non-treated AZNd. SG/TC mode results revealed a drastic decrease in H2 evolution due to the Pr treatment. Mapping the local insulating characteristics using AC-SECM showed higher conductivity of the surface where H2 evolution was most favorable.
Resumo:
Recently, a renewed attention has been drawn into the dart-thrower's motion as the radiocarpal joint is unique to humans and this is believed to have played a pivotal role in human evolution. Considering the importance of the motion and the complexity of the wrist joint, there have been many articles discussing the kinematics behind this movement. CT scan techniques have been used in a number of these research activities. Due to limitations in the speed of the image acquisition, the positions of the wrist were recorded in static postures. To our knowledge, a data acquisition for the motion with realtime capturing has not been reported. This paper presents the use of a 3D vision-based motion capture device. Leap Motion Controller (LMC), for measuring the radiocarpal joint angles during the dart-thrower's motion in a real-time analysis. The practical capability of the LMC in measuring dart-thrower's motion was examined in a trial involving four subjects and the angles were compared to the angles acquired from an inertial measurement unit (IMU). The results confirmed the LMC can successfully be used in the application of measuring radiocarpal kinematics" of dart-thrower's motion.
Resumo:
Bonegilla, Australia's largest post-war migrant processing and reception centre, re-emerged in the public sphere from the late 1980s. A reunion festival was staged on the grounds of the former centre in 1987. Widely attended by former residents, it was considered a success by its organisers, a grass-roots committee of former residents. Another reunion was held ten years later, this time by a committee led by local council members. Both these reunions are important moments in the formation of Bonegilla's public history and its orientation to a narrative of progress and Australian multiculturalism. Analysing them highlights wider changes in heritage discourses and management, and in the evolution of multiculturalism in Australia. Many recent studies of public commemorations in Australia have argued that vernacular or participatory commemorations can be, and almost inevitably are, overtaken and dominated by state-sanctioned narratives. In this article, I will focus on these two reunions in order to argue that despite the progressive dominance of official or institutional powers over Bonegilla's public history, participants’ voices endure within or alongside official frameworks. Despite the obvious differences between the 1987 and 1997 reunions, collective and individual recollections from ex-residents and their families creatively operate within established and seemingly official narrative frameworks. These are not restrictive, nor do they silence alternative articulations. Some ex-residents actively draw on the narrative frameworks available to them to attribute new significance to their experiences, whether melancholy or fond, and consequently include alternative stories that add further to Bonegilla's public multi-vocality.
Resumo:
The Utopian (R)evolution proposes that the utopian fantasy precedes ideology and that utopian literature has evolved from being a tool of wish-fulfilment to becoming one of traversal. Into the Machine combines an electronic reading environment, psychometric testing, and a branching utopian narrative to imagine the next step in this evolution.
Resumo:
Ageing influences gait patterns which in turn can affect the balance control of human locomotion. Entropy-based regularity and complexity measures have been highly effective in analysing a broad range of physiological signals. Minimum toe clearance (MTC) is an event during the swing phase of the gait cycle and is highly sensitive to the spatial balance control properties of the locomotor system. The aim of this research was to investigate the regularity and complexity of the MTC time series due to healthy ageing and locomotors' disorders. MTC data from 30 healthy young (HY), 27 healthy elderly (HE) and 10 falls risk (FR) elderly subjects with balance problems were analysed. Continuous MTC data were collected and using the first 500 data points, MTC mean, standard deviation (SD) and entropy-based complexity analysis were performed using sample entropy (SampEn) for different window lengths (m) and filtering levels (r). The MTC SampEn values were lower in the FR group compared to the HY and HE groups for all m and r. The HY group had a greater mean SampEn value than both HE and FR reflecting higher complexity in their MTC series. The mean SampEn values of HY and FR groups were found significantly different for m = 2, 4, 5 and r = (0.1-0.9) × SD, (0.3-0.9) × SD and (0.3-0.9) × SD, respectively. They were also significant difference between HE and FR groups for m = 4-5 and r = (0.3-0.7) × SD, but no significant differences were seen between HY and HE groups for any m and r. A significant correlation of SampEn with SD of MTC was revealed for the HY and HE groups only, suggesting that locomotor disorders could significantly change the regularity or the complexity of the MTC series while healthy ageing does not. These results can be usefully applied to the early diagnosis of common gait pathologies.