Hierarchical forecasts for Australian domestic tourism

In this paper we explore the hierarchical nature of tourism demand time series and produce short-term forecasts for Australian domestic tourism. The data and forecasts are organized in a hierarchy based on disaggregating the data for different geographical regions and for different purposes of travel. We consider five approaches to hierarchical forecasting: two variations of the top-down approach, the bottom-up method, a newly proposed top-down approach where top-level forecasts are disaggregated according to forecasted proportions of lower level series, and a recently proposed optimal combination approach. Our forecast performance evaluation shows that the top-down approach based on forecast proportions and the optimal combination method perform best for the tourism hierarchies we consider. By applying these methods, we produce detailed forecasts for the Australian domestic tourism market.Australia, exponential smoothing, hierarchical forecasting, innovations state space models, optimal combination forecasts, top-down method, tourism demand.

Optimal combination forecasts for hierarchical time series

In many applications, there are multiple time series that are hierarchically organized and can be aggregated at several different levels in groups based on products, geography or some other features. We call these "hierarchical time series". They are commonly forecast using either a "bottom-up" or a "top-down" method. In this paper we propose a new approach to hierarchical forecasting which provides optimal forecasts that are better than forecasts produced by either a top-down or a bottom-up approach. Our method is based on independently forecasting all series at all levels of the hierarchy and then using a regression model to optimally combine and reconcile these forecasts. The resulting revised forecasts add up appropriately across the hierarchy, are unbiased and have minimum variance amongst all combination forecasts under some simple assumptions. We show in a simulation study that our method performs well compared to the top-down approach and the bottom-up method. It also allows us to construct prediction intervals for the resultant forecasts. Finally, we apply the method to forecasting Australian tourism demand where the data are disaggregated by purpose of visit and geographical region.Bottom-up forecasting, combining forecasts, GLS regression, hierarchical forecasting, Moore-Penrose inverse, reconciling forecasts, top-down forecasting.

Multi-input distributed classifiers for synthetic genetic circuits

For practical construction of complex synthetic genetic networks able to perform elaborate functions it is important to have a pool of relatively simple "bio-bricks" with different functionality which can be compounded together. To complement engineering of very different existing synthetic genetic devices such as switches, oscillators or logical gates, we propose and develop here a design of synthetic multiple input distributed classifier with learning ability. Proposed classifier will be able to separate multi-input data, which are inseparable for single input classifiers. Additionally, the data classes could potentially occupy the area of any shape in the space of inputs. We study two approaches to classification, including hard and soft classification and confirm the schemes of genetic networks by analytical and numerical results

Imperialism, Colonialism and Racism in Joseph Conrad's Heart of Darkness: A Postcolonial Approach

It is not easy to explore the inner side and the hidden nature of human beings. It is also what has strengthened the relationship between human beings and the issue of imperialism and colonialism and the final stage of colonialism which leads to racism. This paper deals with colonialism, imperialism, and racism in Joseph Conrad's novella, Heart of Darkness. The three stages colonizers implement during colonizing African countries.  Modern age and modern literature are shed light on in general and more particularly, modern novel is focused on as it is necessary for the analysis of the novel. Then the terms of colonialism, imperialism, and racism are explored in Heart of Darkness as these are interrelated words having close links to colonization. A postcolonial approach is used to analyze the novella

Bacterial chemotaxis towards the extracellular products of the toxic phytoplankton Heterosigma akashiwo

Marine bacteria exhibit positive chemotactic responses to the extracellular exudates of the toxic phytoplankton Heterosigma akashiwo. In the environment, this will support bacteria–algae associations with potential implications for harmful algal bloom dynamics.National Science Foundation (U.S.) (OCE-0526241)National Science Foundation (U.S.) (OCE-0744641 CAREER)Australian Research Council (Discovery Grant)Massachusetts Institute of Technology. Energy Initiative (Martin Family Society of Fellows for Sustainability Fellowship