Lost Oscillations: Exploring a City’s Space and Time With an Interactive Auditory Art Installation

Presented at the 22nd International Conference on Auditory Display (ICAD-2016)Lost Oscillations is a spatio-temporal sound art installation that allows users to explore the past and present of a city's soundscape. Participants are positioned in the center of an octophonic speaker array; situated in the middle of the array is a touch-sensitive user interface. The user interface is a stylized representation of a map of Christchurch, New Zealand, with electrodes placed throughout the map. Upon touching an electrode, one of many sound recordings made at the electrode's real-world location is chosen and played; users must stay in contact with the electrodes in order for the sounds to continue playing, requiring commitment from users in order to explore the soundscape. The sound recordings have been chosen to represent Christchurch's development throughout its history, allowing participants to explore the evolution of the city from the early 20th Century through to its post-earthquake reconstruction. This paper discusses the motivations for Lost Oscillations before presenting the installation's design, development, and presentation

Modeling the optimal factors affecting combine harvester header losses

Combine header loss comprises more than 50% of wheat harvesting losses.  Therefore, decline in this part of the loss to the extent allowed amount is an important step in reducing of crop wastes.  Combine header is a complex system in which several factors are involved in its work.  And, if these factors can be adjusted and controlled to suit the working conditions, to a large extent of crop loss can be prevented during the harvest.  In this study, reel index, cutting height of crop and horizontal and vertical distance of reel from cutter bar were selected as the effective factors in header loss.  In response surface method, central composite design was used to modeling and finding optimal levels of mentioned factors.  The results showed that power model was the best model to describe the dependence of the independent variables and the dependent variable.  The optimum conditions for minimum combine header loss (103 kg/ha) were obtained 1.2, 25 and 5 for reel index, cutting height of crop and horizontal and vertical distances of reel from cutter bar, respectively

Temporal Evolution of Flow in Pore-Networks: From Homogenization to Instability

We study the dynamics of flow-networks in porous media using a pore-network model. First, we consider a class of erosion dynamics assuming a constitutive law depending on flow rate, local velocities, or shear stress at the walls. We show that depending on the erosion law, the flow may become uniform and homogenized or become unstable and develop channels. By defining an order parameter capturing these different behaviors we show that a phase transition occurs depending on the erosion dynamics. Using a simple model, we identify quantitative criteria to distinguish these regimes and correctly predict the fate of the network, and discuss the experimental relevance of our result.Comment: 5 pages, 4 figures, plus S

Using a hedging network to minimize portfolio risk

This paper develops a useful tool based on hedging networks that allows portfolio managers to allocate capital so as to build portfolios with low risk. We apply a popular measure from the network literature, the Katz centrality measure, to summarize how a security relates to other securities in the network (hedging relations) and to itself (unhedgeable component). We generate empirical evidence that picking stocks with the lowest value of the Katz centrality measure leads to portfolios with a low variance. We show that these portfolios achieve lower variance than other classical portfolio strategies, both in-sample and out-of-sample

Improving the performance of mechanical stirring in biogas plant by computational fluid dynamics (CFD)

Stirring of material in biogas plant needs to be done to provide desirable contact between microorganisms and substrate which can improve digestion process. In the present study, computational fluid dynamics (CFD) was used to determine a suitable mechanical stirrer for biogas plant and simulate the flow pattern. In order to select optimum design of impeller, three types of impeller including six-blade turbine, four-blade turbine and six-flat-blade disc turbine were evaluated. Simulations were undertaken utilizing Fluent 15.0 software with a multiple reference frame approach via standard k-ε turbulence model under steady-state conditions. According to the simulation results, six-blade turbine impeller is more appropriate than the two other impellers. The results further indicated that, this type of stirrer offers suitable mixing both at the center and on the lateral walls of the reactor, reducing dead spaces and improving mass and heat transfers inside the reactor