108 resultados para Lot sizing and scheduling problems


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Recent developments in sensor networks and cloud computing saw the emergence of a new platform called sensor-clouds. While the proposition of such a platform is to virtualise the management of physical sensor devices, we foresee novel applications being created based on a new class of social sensors. Social sensors are effectively a human-device combination that sends torrents of data as a result of social interactions. The data generated appear in different formats such as photographs, videos, or short texts, etc. Unlike other sensor devices, social sensors operate on the control of individuals via their mobile devices like smart phones, tablets or laptops. Further, they do not generate data at a constant rate or format like other sensors do. Instead, data from social sensors are spurious and varied, often in response to social events, or a news announcement of interests to the public. This collective presence of social data creates opportunities for novel applications never experienced before. This paper discusses three such applications utilising social sensors within a sensor-cloud environment. Consequently, the associated research problems are also presented.

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Recent developments in sensor networks and cloud computing saw the emergence of a new platform called sensor-clouds. While the proposition of such a platform is to virtualise the management of physical sensor devices, we are seeing novel applications been created based on a new class of social sensors. Social sensors are effectively a human-device combination that sends torrent of data as a result of social interactions and social events. The data generated appear in different formats such as photographs, videos and short text messages. Unlike other sensor devices, social sensors operate on the control of individuals via their mobile devices such as a phone or a laptop. And unlike other sensors that generate data at a constant rate or format, social sensors generate data that are spurious and varied, often in response to events as individual as a dinner outing, or a news announcement of interests to the public. This collective presence of social data creates opportunities for novel applications never experienced before. This paper discusses such applications as a result of utilising social sensors within a sensor-cloud environment. Consequently, the associated research problems are also presented.

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Objective
To evaluate a prevention program for infant sleep and cry problems and postnatal depression.

Methods
Randomized controlled trial with 781 infants born at 32 weeks or later in 42 well-child centers, Melbourne, Australia. Follow-up occurred at infant age 4 and 6 months. The intervention including supplying information about normal infant sleep and cry patterns, settling techniques, medical causes of crying and parent self-care, delivered via booklet and DVD (at infant age 4 weeks), telephone consultation (8 weeks), and parent group (13 weeks) versus well-child care. Outcomes included caregiver-reported infant night sleep problem (primary outcome), infant daytime sleep, cry and feeding problems, crying and sleep duration, caregiver depression symptoms, attendance at night wakings, and formula changes.

Results
Infant outcomes were similar between groups. Relative to control caregivers, intervention caregivers at 6 months were less likely to score >9 on the Edinburgh Postnatal Depression Scale (7.9%, vs 12.9%, adjusted odds ratio [OR] 0.57, 95% confidence interval [CI] 0.34 to 0.94), spend >20 minutes attending infant wakings (41% vs 51%, adjusted OR 0.66, 95% CI 0.46 to 0.95), or change formula (13% vs 23%, P < .05). Infant frequent feeders (>11 feeds/24 hours) in the intervention group were less likely to have daytime sleep (OR 0.13, 95% CI 0.03 to 0.54) or cry problems (OR 0.27, 95% CI 0.08 to 0.86) at 4 months.

Conclusions
An education program reduces postnatal depression symptoms, as well as sleep and cry problems in infants who are frequent feeders. The program may be best targeted to frequent feeders.

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 Investigation parent and family factors associated with service use for adolescent emotional and behavioural problems, finding that parent problem recognition, sociodemographic variables, prior service use, and parental overcontrol were significantly associated with service use longitudinally. Predictors of parent problem perception were also identified, extending existing research and models.

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Background: This study investigated the relationship among negative affect, body image disturbances (BID), and interpersonal problems, and the mediating effect of self-esteem in a group of treatment-seeking obese individuals. Methods: Four hundred twenty-two obese patients (85 males and 337 females) completed standardised measures that assessed negative affect, BID, self-esteem, and interpersonal problems. Results: Structural equation modelling showed that obese individuals with greater negative affect and BID reported higher interpersonal problems and that self-esteem mediated the relationships among negative affect, BID, and interpersonal problems. Conclusions: The mediating role of self-esteem in the relationship between interpersonal functioning and psychological distress needs to be considered when selecting psychologically based interventions that aim to improve the well-being of treatment-seeking obese patients. © 2014 The Australian Psychological Society.

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OBJECTIVE: To examine (a) physical and daily functioning in children with ADHD and autism spectrum disorder (ASD) compared with ADHD alone and (b) whether decreased physical quality of life (QoL) is associated with increased emotional and behavioral problems in children with ADHD-ASD. METHOD: Cross-sectional study comprising 392 children with confirmed ADHD (ADHD-ASD, n = 93; ADHD alone, n = 299) recruited from 21 pediatric practices in Victoria, Australia. Data were collected via parent and teacher surveys. Key measures included the Strengths and Difficulties Questionnaire (SDQ) and Pediatric Quality of Life Inventory (PedsQL). RESULTS: Children with ADHD-ASD had poorer QoL across both psychosocial and physical health domains, and also had greater parent-reported behavioral, emotional, and peer problems, compared with children with ADHD alone. Poorer physical QoL partially mediated the relationship between comorbid ASD status and poorer emotional and behavioral functioning. CONCLUSION: The comorbid overlay of ASD in ADHD appears to influence not only problems in physical functioning but also the severity of problems relating to areas of emotional and behavioral functioning.

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There has been a resurgence in activity by non-traditional donors (NTDs) since 2000. These flows of foreign development assistance (FDA) are a reflection of the global shift in production and income towards semi-peripheral economies, above all the People’s Republic of China (PRC). The PRC has also adopted its “peaceful rise” and “non-interference” policies with a strong emphasis on South-South cooperation. Some even foresee these changes as opening the space for more public-investment focused development policies, with NTDs providing ready access to capital with few conditionalities. Little attention, however, has been focused how these changes are already impacting in Southeast Asia. The PRC has now become the second largest source of FDA in the Philippines, funding major rail and other infrastructure projects and this trend is set to continue. The experience so far, however, suggests that the Philippine “soggy state” – where the state lacks autonomy from elite classes and processes that hinder development processes - has meant little benefit has accrued from the availability of concessional finance. Despite the rhetoric of “non-interference” in PRC policy, there is evidence that these FDA flows may indeed be aggravating processes of social and political exclusion.

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Over the last three decades, community and professional views of what constitutes significant cultural heritage have broadened in many countries around the world. Heritage practice has moved from a narrowly technical or fabric focus to a values-based approach engaging all stakeholders, including indigenous communities. While much Western heritage knowledge and practice remains indispensable, gaps can be filled in by drawing on other knowledge areas and ethical considerations, including links between heritage practice and human rights. These new directions require new approaches in the preparation of practitioners as well as others engaged in heritage processes. In addition to education and training, a third concept – capacity-building – is overarching and potentially powerful in reaching new heritage actors. The aim of giving heritage a valued role in the life of the community, which applies at global, national, and local levels, represents the greatest challenge for educators, trainers, and capacity-builders in the contemporary world.

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The Kidney Exchange Problem (KEP) is a combinatorial optimization problem and has attracted the attention from the community of integer programming/combinatorial optimisation in the past few years. Defined on a directed graph, the KEP has two variations: one concerns cycles only, and the other, cycles as well as chains on the same graph. We call the former a Cardinality Constrained Multi-cycle Problem (CCMcP) and the latter a Cardinality Constrained Cycles and Chains Problem (CCCCP). The cardinality for cycles is restricted in both CCMcP and CCCCP. As for chains, some studies in the literature considered cardinality restrictions, whereas others did not. The CCMcP can be viewed as an Asymmetric Travelling Salesman Problem that does allow subtours, however these subtours are constrained by cardinality, and that it is not necessary to visit all vertices. In existing literature of the KEP, the cardinality constraint for cycles is usually considered to be small (to the best of our knowledge, no more than six). In a CCCCP, each vertex on the directed graph can be included in at most one cycle or chain, but not both. The CCMcP and the CCCCP are interesting and challenging combinatorial optimization problems in their own rights, particularly due to their similarities to some travelling salesman- and vehicle routing-family of problems. In this paper, our main focus is to review the existing mathematical programming models and solution methods in the literature, analyse the performance of these models, and identify future research directions. Further, we propose a polynomial-sized and an exponential-sized mixed-integer linear programming model, discuss a number of stronger constraints for cardinality-infeasible-cycle elimination for the latter, and present some preliminary numerical results.

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One of the core ideas that animate neo-liberal globalization is the promise that with increased integration there will be a concomitant decline in the power of the nation state and a decline and dissipation of issues such as ethnic hatred, nationalist extremism which can be overcome by the spread of enlightened self interest. Competition based on individual merit and the prevalence of markets over politics signals a new neo-liberal order. According to its supporters neo-liberal globalization heralds a new era of cosmopolitanism individualism, choice and the breakdown of barriers to the peoples of the world. Freedom, free markets, open competition, democracy and development are said to follow in the wake of neoliberal globalization. The powerful discourse of competition and economic development provides neo-liberal globalization with a critical and central driver

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Scientific workflow offers a framework for cooperation between remote and shared resources on a grid computing environment (GCE) for scientific discovery. One major function of scientific workflow is to schedule a collection of computational subtasks in well-defined orders for efficient outputs by estimating task duration at runtime. In this paper, we propose a novel time computation model based on algorithm complexity (termed as TCMAC model) for high-level data intensive scientific workflow design. The proposed model schedules the subtasks based on their durations and the complexities of participant algorithms. Characterized by utilization of task duration computation function for time efficiency, the TCMAC model has three features for a full-aspect scientific workflow including both dataflow and control-flow: (1) provides flexible and reusable task duration functions in GCE;(2) facilitates better parallelism in iteration structures for providing more precise task durations;and (3) accommodates dynamic task durations for rescheduling in selective structures of control flow. We will also present theories and examples in scientific workflows to show the efficiency of the TCMAC model, especially for control-flow. Copyright©2009 John Wiley & Sons, Ltd.

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Over the years many researchers have been investigating the area of MRP production planning and still is an area of high interest today. This paper look at production planning where there is unpredictable demands due to the type of product and market a company produces for. Production planning becomes difficult when demand fluctuates unpredictably, and hence a historical sales forecast is used as the initial data for production planning. The sales from previous years, especially in a seasonal market, don't necessarily correlate well to the current and future sales for the next year. A planner working in such environment would have himself frustrating to create a feasible production plan that not only needs to meet customer's demands but also to built up the 'correct' amount of stock for that peak sell season. To overcome some of these problems, This work describes a production planning methodology that can be implemented robustly and quickly. This paper has studied two multi-item lot-sizing problems. We detailed the development of the planning problem mathematically and highlight some solutions to initial problems investigated.