919 resultados para Hydropower scheduling
Resumo:
Changes in mature forest cover amount, composition, and configuration can be of significant consequence to wildlife populations. The response of wildlife to forest patterns is of concern to forest managers because it lies at the heart of such competing approaches to forest planning as aggregated vs. dispersed harvest block layouts. In this study, we developed a species assessment framework to evaluate the outcomes of forest management scenarios on biodiversity conservation objectives. Scenarios were assessed in the context of a broad range of forest structures and patterns that would be expected to occur under natural disturbance and succession processes. Spatial habitat models were used to predict the effects of varying degrees of mature forest cover amount, composition, and configuration on habitat occupancy for a set of 13 focal songbird species. We used a spatially explicit harvest scheduling program to model forest management options and simulate future forest conditions resulting from alternative forest management scenarios, and used a process-based fire-simulation model to simulate future forest conditions resulting from natural wildfire disturbance. Spatial pattern signatures were derived for both habitat occupancy and forest conditions, and these were placed in the context of the simulated range of natural variation. Strategic policy analyses were set in the context of current Ontario forest management policies. This included use of sequential time-restricted harvest blocks (created for Woodland caribou (Rangifer tarandus) conservation) and delayed harvest areas (created for American marten (Martes americana atrata) conservation). This approach increased the realism of the analysis, but reduced the generality of interpretations. We found that forest management options that create linear strips of old forest deviate the most from simulated natural patterns, and had the greatest negative effects on habitat occupancy, whereas policy options that specify deferment and timing of harvest for large blocks helped ensure the stable presence of an intact mature forest matrix over time. The management scenario that focused on maintaining compositional targets best supported biodiversity objectives by providing the composition patterns required by the 13 focal species, but this scenario may be improved by adding some broad-scale spatial objectives to better maintain large blocks of interior forest habitat through time.
Resumo:
Interdependency and Care over the Lifecourse draws upon theories of time and space to consider how informal care is woven into the fabric of everyday lives and is shaped by social and economic inequalities and opportunities. The book comprises three parts. The first explores contrasting social and economic contexts of informal care in different parts of the world. The second looks at different themes and dynamics of caring, using fictional vignettes of illness and health, child care, elderly care and communities of care. The book examines the significance to practices of care throughout the lifecourse of: understandings and expectations of care emotional exchanges involved in care memories and anticipations of giving and receiving care the social nature of the spaces and places in which care is carried out the practical time-space scheduling necessary to caring activities. Finally the authors critically examine how the frameworks of caringscapes and carescapes might be used in research, policy and practice. A working example is provided. This book will be of interest to students and researchers of care work, health and social care, geography, sociology of the family and social policy as well as those in business and policy communities trying to gain an understanding of how work and informal care interweave
Resumo:
The regional population of the Grey-headed Fish-Eagle (Ichthyophaga ichthyaetus) in Southeast Asia is thought to be in recent decline and its conservation status Linder threat. We undertook a systematic survey in a flooded swamp forest at the Tonle Sap Lake in Cambodia and recorded 32 pairs of eagles in an area of approximately 80 km(2). Three species of water snakes were identified as eagle prey items, previously unrecorded for this species. We suggest that this eagle population has significant regional importance and discuss potential anthropogenic threats to population stability, such as water snake harvesting and construction Of upstream hydropower dams.
Resumo:
Improving plant quality and the uniformity of a crop are major objectives for growers of ornamental nursery stock. The potential to control excess vigour and to improve quality through regulated deficit irrigation (RDI) was investigated using a range of woody ornamental species. RDI regimes reduced vegetative growth consistently across different species and growing seasons. Plants adapted to reduced water supplies primarily via stomatal control, but also by osmotic adjustment when grown under the most severe RDI regimes. Only plants exposed to <= 25% of potential evapo-transpiration demonstrated any evidence of leaf injury, and the extent was slight. Growth inhibition increased as the severity of RDI increased. Improvements in quality were attained through a combination of shorter internodes and final shoot lengths, yet the number of 'formative' primary shoots remained unaffected. Compact, well-branched plants could be formed without a requirement for mid-season pruning. In addition to severity, the timing of RDI also influenced growth responses. Applying 50% ETp for 8 weeks during July-August resulted in the formation of good quality plants, which retained their shape until the following Spring. Re-positioning irrigation drippers within the pots of well-watered plants, in an attempt to induce a partial root drying (PRD) treatment, reduced growth, but not significantly. The adoption of irrigation scheduling, based on 50-100% ETp, has the potential to improve commercial crop quality across a range of ornamental species.
Resumo:
Extending the season of production and improving the scheduling of ornamental crops are key commercial objectives for nurserymen. In some woody species, the period in which cuttings can be rooted successfully is transient, thus limiting the opportunities for scheduled production. Optimum rooting often occurs in early- to mid-summer coinciding with periods of active shoot growth. The relationship between this shoot activity and root initiation was investigated in Cotinus coggygria 'Royal Purple'. Shoot growth on stock plants was manipulated by altering the photoperiod or light quality. Results indicated there were seasonal effects on rooting, but the importance of shoot activity varied with harvest time. Cuttings harvested in August had high rooting percentages, irrespective of photoperiod, and despite shoot growth terminating in response to the short-day treatment. In contrast, by September, rooting percentage was highest in cuttings from plants under long-days, which had maintained greatest shoot growth activity. Cotinus shoots grown in vitro under 16 h days showed reduced shoot growth and increased rooting competence compared with shoots grown under 8 h days. Growing stock plants under polythene films, which altered the amount and quality of the incident light, influenced the rooting of cuttings harvested in August, but no consistent relationship with shoot activity was apparent. From a practical viewpoint, maintaining shoot activity late in the season may prolong the period for propagation by cuttings; but, from a scientific viewpoint, processes associated with an active shoot apex do not provide a complete explanation of seasonal variation in rooting.
Resumo:
Very large scale scheduling and planning tasks cannot be effectively addressed by fully automated schedule optimisation systems, since many key factors which govern 'fitness' in such cases are unformalisable. This raises the question of an interactive (or collaborative) approach, where fitness is assigned by the expert user. Though well-researched in the domains of interactively evolved art and music, this method is as yet rarely used in logistics. This paper concerns a difficulty shared by all interactive evolutionary systems (IESs), but especially those used for logistics or design problems. The difficulty is that objective evaluation of IESs is severely hampered by the need for expert humans in the loop. This makes it effectively impossible to, for example, determine with statistical confidence any ranking among a decent number of configurations for the parameters and strategy choices. We make headway into this difficulty with an Automated Tester (AT) for such systems. The AT replaces the human in experiments, and has parameters controlling its decision-making accuracy (modelling human error) and a built-in notion of a target solution which may typically be at odds with the solution which is optimal in terms of formalisable fitness. Using the AT, plausible evaluations of alternative designs for the IES can be done, allowing for (and examining the effects of) different levels of user error. We describe such an AT for evaluating an IES for very large scale planning.
Resumo:
This paper describes the design, implementation and testing of an intelligent knowledge-based supervisory control (IKBSC) system for a hot rolling mill process. A novel architecture is used to integrate an expert system with an existing supervisory control system and a new optimization methodology for scheduling the soaking pits in which the material is heated prior to rolling. The resulting IKBSC system was applied to an aluminium hot rolling mill process to improve the shape quality of low-gauge plate and to optimise the use of the soaking pits to reduce energy consumption. The results from the trials demonstrate the advantages to be gained from the IKBSC system that integrates knowledge contained within data, plant and human resources with existing model-based systems. (c) 2005 Elsevier Ltd. All rights reserved.
Resumo:
This paper presents a queue-based agent architecture for multimodal interfaces. Using a novel approach to intelligently organise both agents and input data, this system has the potential to outperform current state-of-the-art multimodal systems, while at the same time allowing greater levels of interaction and flexibility. This assertion is supported by simulation test results showing that significant improvements can be obtained over normal sequential agent scheduling architectures. For real usage, this translates into faster, more comprehensive systems, without the limited application domain that restricts current implementations.
Resumo:
The academic discipline of television studies has been constituted by the claim that television is worth studying because it is popular. Yet this claim has also entailed a need to defend the subject against the triviality that is associated with the television medium because of its very popularity. This article analyses the many attempts in the later twentieth and twenty-first centuries to constitute critical discourses about television as a popular medium. It focuses on how the theoretical currents of Television Studies emerged and changed in the UK, where a disciplinary identity for the subject was founded by borrowing from related disciplines, yet argued for the specificity of the medium as an object of criticism. Eschewing technological determinism, moral pathologization and sterile debates about television's supposed effects, UK writers such as Raymond Williams addressed television as an aspect of culture. Television theory in Britain has been part of, and also separate from, the disciplinary fields of media theory, literary theory and film theory. It has focused its attention on institutions, audio-visual texts, genres, authors and viewers according to the ways that research problems and theoretical inadequacies have emerged over time. But a consistent feature has been the problem of moving from a descriptive discourse to an analytical and evaluative one, and from studies of specific texts, moments and locations of television to larger theories. By discussing some historically significant critical work about television, the article considers how academic work has constructed relationships between the different kinds of objects of study. The article argues that a fundamental tension between descriptive and politically activist discourses has confused academic writing about ›the popular‹. Television study in Britain arose not to supply graduate professionals to the television industry, nor to perfect the instrumental techniques of allied sectors such as advertising and marketing, but to analyse and critique the medium's aesthetic forms and to evaluate its role in culture. Since television cannot be made by ›the people‹, the empowerment that discourses of television theory and analysis aimed for was focused on disseminating the tools for critique. Recent developments in factual entertainment television (in Britain and elsewhere) have greatly increased the visibility of ›the people‹ in programmes, notably in docusoaps, game shows and other participative formats. This has led to renewed debates about whether such ›popular‹ programmes appropriately represent ›the people‹ and how factual entertainment that is often despised relates to genres hitherto considered to be of high quality, such as scripted drama and socially-engaged documentary television. A further aspect of this problem of evaluation is how television globalisation has been addressed, and the example that the issue has crystallised around most is the reality TV contest Big Brother. Television theory has been largely based on studying the texts, institutions and audiences of television in the Anglophone world, and thus in specific geographical contexts. The transnational contexts of popular television have been addressed as spaces of contestation, for example between Americanisation and national or regional identities. Commentators have been ambivalent about whether the discipline's role is to celebrate or critique television, and whether to do so within a national, regional or global context. In the discourses of the television industry, ›popular television‹ is a quantitative and comparative measure, and because of the overlap between the programming with the largest audiences and the scheduling of established programme types at the times of day when the largest audiences are available, it has a strong relationship with genre. The measurement of audiences and the design of schedules are carried out in predominantly national contexts, but the article refers to programmes like Big Brother that have been broadcast transnationally, and programmes that have been extensively exported, to consider in what ways they too might be called popular. Strands of work in television studies have at different times attempted to diagnose what is at stake in the most popular programme types, such as reality TV, situation comedy and drama series. This has centred on questions of how aesthetic quality might be discriminated in television programmes, and how quality relates to popularity. The interaction of the designations ›popular‹ and ›quality‹ is exemplified in the ways that critical discourse has addressed US drama series that have been widely exported around the world, and the article shows how the two critical terms are both distinct and interrelated. In this context and in the article as a whole, the aim is not to arrive at a definitive meaning for ›the popular‹ inasmuch as it designates programmes or indeed the medium of television itself. Instead the aim is to show how, in historically and geographically contingent ways, these terms and ideas have been dynamically adopted and contested in order to address a multiple and changing object of analysis.
Resumo:
In this article, an overview is given of some of the more common approaches taken in applying adaptive control. Gain scheduling, model reference control and self-tuning control are all discussed and in each case suggestions are given for further reading.
Resumo:
A new generation of advanced surveillance systems is being conceived as a collection of multi-sensor components such as video, audio and mobile robots interacting in a cooperating manner to enhance situation awareness capabilities to assist surveillance personnel. The prominent issues that these systems face are: the improvement of existing intelligent video surveillance systems, the inclusion of wireless networks, the use of low power sensors, the design architecture, the communication between different components, the fusion of data emerging from different type of sensors, the location of personnel (providers and consumers) and the scalability of the system. This paper focuses on the aspects pertaining to real-time distributed architecture and scalability. For example, to meet real-time requirements, these systems need to process data streams in concurrent environments, designed by taking into account scheduling and synchronisation. The paper proposes a framework for the design of visual surveillance systems based on components derived from the principles of Real Time Networks/Data Oriented Requirements Implementation Scheme (RTN/DORIS). It also proposes the implementation of these components using the well-known middleware technology Common Object Request Broker Architecture (CORBA). Results using this architecture for video surveillance are presented through an implemented prototype.
Resumo:
This is a comprehensive textbook for students of Television Studies, now updated for its third edition. The book provides students with a framework for understanding the key concepts and main approaches to Television Studies, including audience research, television history and broadcasting policy, and the analytical study of individual programmes. The book includes a glossary of key terms used in the television industry and in the academic study of television, there are suggestions for further reading at the end of each chapter, and chapters include suggested activities for use in class or as assignments. The case studies in the book include analysis of advertisements, approaches to news reporting, television scheduling, and challenges to television in new contexts of viewing on computers and mobile devices. The topics of individual chapters are: studying television, television histories, television cultures, television texts and narratives, television genres and formats, television production, television quality and value, television realities and representation, television censorship and regulation, television audiences, and the likely future for television.
Resumo:
In today's global economic conditions, improving the productivity of the construction industry is becoming more pressing than ever. Several factors impact the efficiency of construction operatives, but motivation is among the most important. Since low productivity is one of the significant challenges facing the construction industry in the State of Kuwait, the objective of this case study is to identify, explore, and rank the relative importance of the factors perceived to impact the motivational level of master craftsmen involved in primary construction trades. To achieve this objective, a structured questionnaire survey comprising 23 factors, which were shortlisted based on relevant previous research on motivation, the input of local industry experts, and numerous interviews with skilled operatives, was distributed to a large number of master craftsmen. Using the “Relative Importance Index” technique, the following prominent factors are identified: (1) payment delay; (2) rework; (3) lack of a financial incentive scheme; (4) the extent of change orders during execution; (5) incompetent supervisors; (6) delays in responding to Requests For Information (RFI); (7) overcrowding and operatives interface; (8) unrealistic scheduling and performance expectation; (9) shortage of materials on site; and (10) drawings quality level. The findings can be used to provide industry practitioners with guidance for focusing, acting upon, and controlling the critical factors influencing the performance of master craftsmen, hence, assist in achieving an efficient utilization of the workforce, and a reasonable level of competitiveness and cost effective operation.