59 resultados para Integrated agricultural systems
em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast
Resumo:
Despite the substantial organisational benefits of integrated IT, the implementation of such systems – and particularly Enterprise Resource Planning (ERP) systems – has tended to be problematic, stimulating an extensive body of research into ERP implementation. This research has remained largely separate from the main IT implementation literature. At the same time, studies of IT implementation have generally adopted either a factor or process approach; both have major limitations. To address these imitations, factor and process perspectives are combined here in a unique model of IT implementation. We argue that • the organisational factors which determine successful implementation differ for integrated and traditional, discrete IT • failure to manage these differences is a major source of integrated IT failure. The factor/process model is used as a framework for proposing differences between discrete and integrated IT.
Resumo:
The research on integrated energy system technology meets the major national strategic needs of China. Focusing on the vital theory of planning and optimal operation of integrated energy system, six fundamental problems in the study of integrated energy system are proposed systematically, including the common modeling technology for integrated energy system, the integrated simulation of integrated energy system, the planning theory and method of integrated energy system, the security theory and method of integrated energy system, the optimal operation and control of integrated energy system, the benefit assessment and operational mechanisms of integrated energy system. The status of domestic and foreign research directions related to each scientific problems are surveyed and anticipated.
Resumo:
ntegrated organisational IT systems, such as enterprise resource planning (ERP), supply chain management (SCM) and digital manufacturing (DM), have promised and delivered substantial performance benefits to many adopting firms. However, implementations of such systems have tended to be problematic. ERP projects, in particular, are prone to cost and time overruns, not delivering anticipated benefits and often being abandoned before completion. While research has developed around IT implementation, this has focused mainly on standalone (or discrete), as opposed to integrated, IT systems. Within this literature, organisational (i.e., structural and cultural) characteristics have been found to influence implementation success. The key aims of this research are (a) to investigate the role of organisational characteristics in determining IT implementation success; (b) to determine whether their influence differs for integrated IT and discrete IT projects; and (c) to develop specific guidelines for managers of integrated IT implementations. An in-depth comparative case study of two IT projects was conducted within a major aerospace manufacturing company.
Resumo:
This paper discusses the importance of integrated sensing systems comprising techniques that give different types of data from a structure exposed to the marine environment so that its service life could reliably be predicted. For this purpose, a novel sensor combination was designed and installed in concrete panels which were exposed to Hangzhou Bay Bridge in China. The integrated sensor probe was used to monitor the cover concrete as well as the reinforcement. The sensor probes were connected to a monitoring station, which enabled access and control of the data remotely from Belfast, UK. The initial data obtained from the monitoring station gives interesting information on the early age properties of concrete and distinct variations in these properties with different types of concrete. This paper also reports the variation in electrical properties of different concrete samples and environmental data in response to the marine exposure condition at Hangzhou bay bridge.
Resumo:
Gas fired generation currently plays an integral support role ensuring security of supply in power systems with high wind power penetrations due to its technical and economic attributes. However, the increase in variable wind power has affected the gas generation output profile and is pushing the boundaries of the design and operating envelope of gas infrastructure. This paper investigates the mutual dependence and interaction between electricity generation and gas systems through the first comprehensive joined-up, multi-vector energy system analysis for Ireland. Key findings reveal the high vulnerability of the Irish power system to outages on the Irish gas system. It has been shown that the economic operation of the power system can be severely impacted by gas infrastructure outages, resulting in an average system marginal price of up to €167/MWh from €67/MWh in the base case. It has also been shown that gas infrastructure outages pose problems for the location of power system reserve provision, with a 150% increase in provision across a power system transmission bottleneck. Wind forecast error was shown to be a significant cause for concern, resulting in large swings in gas demand requiring key gas infrastructure to operate at close to 100% capacity. These findings are thought to increase in prominence as the installation of wind capacity increases towards 2020, placing further stress on both power and gas systems to maintain security of supply.
Resumo:
This paper presents the first multi vector energy analysis for the interconnected energy systems of Great Britain (GB) and Ireland. Both systems share a common high penetration of wind power, but significantly different security of supply outlooks. Ireland is heavily dependent on gas imports from GB, giving significance to the interconnected aspect of the methodology in addition to the gas and power interactions analysed. A fully realistic unit commitment and economic dispatch model coupled to an energy flow model of the gas supply network is developed. Extreme weather events driving increased domestic gas demand and low wind power output were utilised to increase gas supply network stress. Decreased wind profiles had a larger impact on system security than high domestic gas demand. However, the GB energy system was resilient during high demand periods but gas network stress limited the ramping capability of localised generating units. Additionally, gas system entry node congestion in the Irish system was shown to deliver a 40% increase in short run costs for generators. Gas storage was shown to reduce the impact of high demand driven congestion delivering a reduction in total generation costs of 14% in the period studied and reducing electricity imports from GB, significantly contributing to security of supply.
Resumo:
Many insect species vary in their degree of foraging specialisation, with many bee species considered polyphagic (polylectic). Wild, non-managed bee species vary in their conservation status, and species-specific biological traits such as foraging specialisation may play an important role in determining variance in population declines. Current agri-environment schemes (AESs) prescribe the introduction of flower seed mixes for agricultural systems to aid the conservation of wild bees. However, the extent to which flower combinations adequately meet bee foraging requirements is poorly known. We quantitatively assessed pollen use and selectivity using two statistical approaches: Bailey's Intervals and Compositional Analysis, in an examplar species, a purportedly polylectic and rare bee, Colletes floralis, across 7 sites through detailed analysis of bee scopal pollen loads and flower abundance. Both approaches provided good congruence, but Compositional Analysis was more robust to small sample sizes. We advocate its use for the quantitative determination of foraging behaviour and dietary preference. Although C. floralis is polylectic, it showed a clear dietary preference for plants within the family Apiaceae. Where Apiaceae was uncommon, the species exploited alternative resources. Other plant families, such as the Apiaceae, could be included, or have their proportion increased in AES seed mixes, to aid the management of C. floralis and potentially other wild solitary bees of conservation concern. © 2011 The Authors. Insect Conservation and Diversity © 2011 The Royal Entomological Society.
Resumo:
1. The population characteristics and distribution of wood mice Apodemus sylvaticus (L.) were investigated along field margins of farmland dominated by grass production. 2. Turnover, sex ratio, breeding season, spatial density dependence and density dependence in reproductive activity indicated that the population ecology of A. sylvaticus is consistent in different habitats in the same geographical region. 3. Spatial variation in the abundance of A.sylvaticus was related negatively to percentage of land under pasture and distance from woodland and positively related to variables associated with food supply and cover. 4. Variation in numbers of overwintered mice at the start of the breeding season was related more closely to breeding opportunity than to environmental factors. This was particularly so in males. 5. The association of overwintered male and female A. sylvaticus remained evident in the later half of the breeding season. Young males and females of the year, however, were distributed more with respect to physical and biological features than towards adults or reproductive opportunity. 6. A. sylvaticus is an important species of field margins, even where these are poorly developed and agriculture is pastoral rather than arable. Further studies of this species in a wider range of agricultural systems are desirable.
Resumo:
The term `laser cooling' is applied to the use of optical means to cool the motional energies of either atoms and molecules, or micromirrors. In the literature, these two strands are kept largely separate; both, however suffer from severe limitations. Laser cooling of atoms and molecules largely relies on the internal level structure of the species being cooled. As a result, only a small number of elements and a tiny number of molecules can be cooled this way. In the case of micromirrors, the problem lies in the engineering of micromirrors that need to satisfy a large number of constraints---these include a high mechanical Q-factor, high reflectivity and very good optical quality, weak coupling to the substrate, etc.---in order to enable efficient cooling. During the course of this thesis, I will draw these two sides of laser cooling closer together by means of a single, generically applicable scattering theory that can be used to explain the interaction between light and matter at a very general level. I use this `transfer matrix' formalism to explore the use of the retarded dipole--dipole interaction as a means of both enhancing the efficiency of micromirror cooling systems and rendering the laser cooling of atoms and molecules less species selective. In particular, I identify the `external cavity cooling' mechanism, whereby the use of an optical memory in the form of a resonant element (such as a cavity), outside which the object to be cooled sits, can potentially lead to the construction of fully integrated optomechanical systems and even two-dimensional arrays of translationally cold atoms, molecules or even micromirrors.
Resumo:
The application of slurry nutrients to land can be associated with unintended losses to the environment depending on soil and weather conditions. Correct timing of slurry application, however, can increase plant nutrient uptake and reduce losses. A decision support system (DSS), which predicts optimum conditions for slurry spreading based on the Hybrid Soil Moisture Deficit (HSMD) model, was investigated for use as a policy tool. The DSS recommendations were compared to farmer perception of suitable conditions for slurry spreading for three soil drainage classes (well, moderate and poorly drained) to better understand on farm slurry management practices and to identify potential conflict with farmer opinion. Six farmers participated in a survey over two and a half years, during which they completed a daily diary, and their responses were compared to Soil Moisture Deficit (SMD) calculations and weather data recorded by on farm meteorological stations. The perception of land drainage quality differed between farmers and was related to their local knowledge and experience. It was found that the allocation of grass fields to HSMD drainage classes using a visual assessment method aligned farmer perception of drainage at the national scale. Farmer opinion corresponded to the theoretical understanding that slurry should not be applied when the soil is wetter than field capacity, i.e. when drainage can occur. While weather and soil conditions (especially trafficability) were the principal reasons given by farmers not to spread slurry, farm management practices (grazing and silage) and current Nitrates Directive policies (closed winter period for spreading) combined with limited storage capacities were obstacles to utilisation of slurry nutrients. Despite the slightly more restrictive advice of the DSS regarding the number of suitable spreading opportunities, the system has potential to address an information deficit that would help farmers to reduce nutrient losses and optimise plant nutrient uptake by improved slurry management. The DSS advice was in general agreement with the farmers and, therefore, they should not be resistant to adopting the tool for day to day management.
Resumo:
In the areas adjacent to the drowned Pleistocene continent of Sunda – present-day Mainland and Island SE Asia – the Austronesian Hypothesis of a diaspora of rice cultivators from Taiwan ∼4200 years ago has often been linked with the start of farming. Mounting evidence suggests that these developments should not be conflated and that alternative explanations should be considered, including indigenous inception of complex patterns of plant food production and early exchange of plants, animals, technology and genes. We review evidence for widespread forest disturbance in the Early Holocene which may accompany the beginnings of complex food-production. Although often insubstantial, evidence for incipient and developing management of rainforest vegetation and of developing complex relationships with plants is present, and early enough to suggest that during the Early to mid-Holocene this vast region was marked by different approaches to plant food production. The trajectory of the increasingly complex relationships between people and their food organisms was strongly locally contingent and in many cases did not result in the development of agricultural systems that were recognisable as such at the time of early European encounters. Diverse resource management economies in the Sunda and neighbouring regions appear to have accompanied rather than replaced a reliance on hunting and gathering. This, together with evidence for Early Holocene interaction between these neighbours, gives cause for us to question some authors continued adherence to a singular narrative of the Austronesian Hypothesis and the ‘Neolithisation’ of this part of the world. It also leads us to suggest that the forests of this vast region are, to an extent, a cultural artefact.
Resumo:
Integrated "ICT chromophore-receptor" systems show ion-induced shifts in their electronic absorption spectra. The wavelength of observation can be used to reversibly configure the system to any of the four logic operations permissible with a single input (YES, NOT, PASS 1, PASS 0), under conditions of ion input and transmittance output. We demonstrate these with dyes integrated into Tsien's calcium receptor, 1-2. Applying multiple ion inputs to 1-2 also allows us to perform two- or three-input OR or NOR operations. The weak fluorescence output of 1 also shows YES or NOT logic depending on how it is configured by excitation and emission wavelengths. Integrated "receptor(1)-ICT chromophore-receptor(2)" systems 3-5 selectively target two ions into the receptor terminals. The ion-induced transmittance output of 3-5 can also be configured via wavelength to illustrate several logic types including, most importantly, XOR. The opposite effects of the two ions on the energy of the chromophore excited state is responsible for this behaviour. INHIBIT and REVERSE IMPLICATION are two of the other logic types seen here. Integration of XOR logic with a preceding OR operation can be arranged by using three ion inputs. The fluorescence output of these systems can be configured via wavelength to display INHIBIT or NOR logic under two-input conditions. The superposition or multiplicity of logic gate configurations is an unusual consequence of the ability to simultaneously observe multiple wavelengths.