Collaborative Exploration and Sensemaking of Big Environmental Sound Data

Many ecologists are using acoustic monitoring to study animals and the health of ecosystems. Technological advances mean acoustic recording of nature can now be done at a relatively low cost, with minimal disturbance, and over long periods of time. Vast amounts of data are gathered yielding environmental soundscapes which requires new forms of visualization and interpretation of the data. Recently a novel visualization technique has been designed that represents soundscapes using dense visual summaries of acoustic patterns. However, little is known about how this visualization tool can be employed to make sense of soundscapes. Understanding how the technique can be best used and developed requires collaboration between interface, algorithm designers and ecologists. We empirically investigated the practices and needs of ecologists using acoustic monitoring technologies. In particular, we investigated the use of the soundscape visualization tool by teams of ecologists researching endangered species detection, species behaviour, and monitoring of ecological areas using long duration audio recordings. Our findings highlight the opportunities and challenges that ecologists face in making sense of large acoustic datasets through patterns of acoustic events. We reveal the characteristic processes for collaboratively generating situated accounts of natural places from soundscapes using visualization. We also discuss the biases inherent in the approach. Big data from nature has different characteristics from social and informational data sources that comprise much of the World Wide Web. We conclude with design implications for visual interfaces to facilitate collaborative exploration and discovery through soundscapes.     

Enzymic oxidation of linolenic acid to 1,Z-5-octadien-3-ol,Z-2,Z-5-octadien-1-ol and 10-oxo-E-8-decenoic acid by a protein fraction from mushrooms (Psalliota bispora)

The pathway for the oxidative cleavage of linolenic acid was investigated using a protein fraction from mushrooms (Psalliota bispora) as the enzyme source. Incubation of the protein fraction with linolenic acid resulted in 1,Z-5-octadien-3(R)-ol and Z-2,Z-5-octadien-1-ol (in a 3∶2 ratio) and 10-oxo-E-8-decenoic acid (10-ODA). Experiments with molecular oxygen-18 indicated that the oxygen in the hydroxy group of both octadienols originates from the gaseous phase and not from water. The protein fraction was incubated with the individual 9-, 10-, 12-, 13-, 15- and 16-hydroperoxide isomers of linolenic acid. Only the 10-hydroperoxy-E-8,Z-12,Z-15-octadecatrienoic acid (10-HPOT) served as substrate, and was cleaved into the two octadienols and the 10-ODA. This result suggests that in the oxidation of linolenic acid by the mushroom fraction the 10-HPOT is an intermediate cleaved by a hydroperoxide lyase into the octadienols and the 10-ODA. Model experiments in which the methyl esters of both 10-hydroperoxy-E-8,Z-12-octadecadienoic acid (10-HPOD) and 10-HPOT were treated with the Lewis acid BF₃ yielded only various C₉ compounds. It was therefore concluded that the reactions of the mushroom hydroperoxide lyase cannot be explained by the heterolytic rearrangement mechanism, which was proposed for the corresponding plant enzyme. β-Scission of the 10-HPOD and the 10-HPOT explains the reactions of the mushroom hydroperoxide lyase and is discussed in detail.     

Modelling and optimization of power consumption in wireless access networks

The power consumption of wireless access networks will become an important issue in the coming years. In this paper, the power consumption of base stations for mobile WiMAX, fixed WiMAX, UMTS, HSPA, and LTE is modelled and related to the coverage. A new metric, the power consumption per covered area PC_area, is introduced, to compare the energy efficiency of the considered technologies for a range of bit rates. Assuming the model parameters are correct, the conclusions are then as follows. For a 5 MHz channel, UMTS is the most energy-efficient technology until a bit rate of 2.8 Mbps, LTE between 2.8 Mbps and 8.2 Mbps, fixed WiMAX between 8.2 Mbps and 13.8 Mbps and finally mobile WiMAX for bit rates higher than 13.8 Mbps. Furthermore, the influence of MIMO is investigated.For a 2 × 2 MIMO system, PC_area decreases by 36% for mobile WiMAX and by 23% for HSPA and LTE compared to the SISO system, resulting in a higher energy efficiency.The power consumption model for base stations is used in the deployment tool GRAND (Green Radio Access Network Design) for green wireless access networks. GRAND uses a genetic based algorithm and is applied on an actual case for the Brussels Capital Region, showing the possibilities of energy-efficient planning.     

Using Value-Focused Thinking to Improve Watersheds

This article presents a process for making decisions about how best to improve the quality of watersheds. Value-focused thinking is an approach to structuring decisions by concentrating on the decision makers' values and preferences rather than the limited alternatives at hand. We describe how we used value-focused thinking to construct a model for measuring the current condition of an urban watershed, Upham Brook, in Richmond, Virginia. The model reflected the values of a 16-member panel and used readily available and commonly collected data as inputs. The results for Upham Brook were compared to those for a hypothetical perfect watershed to reveal gaps or shortcomings that could be targeted for improvement. We also discuss how this process may be applied by planners elsewhere seeking to improve the quality of other watersheds.     

Methodology to estimate the threshold in-cylinder temperature for self-ignition of fuel during cold start of Diesel engines

Cold startability of automotive direct injection (DI) Diesel engines is frequently one of the negative features when these are compared to their closest competitor, the gasoline engine. This situation worsens with the current design trends (engine downsizing) and the emerging new Diesel combustion concepts, such as HCCI, PCCI, etc., which require low compression ratio engines. To mitigate this difficulty, pre-heating systems (glow plugs, air heating, etc.) are frequently used and their technologies have been continuously developed. For the optimum design of these systems, the determination of the threshold temperature that the gas should have in the cylinder in order to provoke the self-ignition of the fuel injected during cold starting is crucial. In this paper, a novel methodology for estimating the threshold temperature is presented. In this methodology, experimental and computational procedures are adequately combined to get a good compromise between accuracy and effort. The measurements have been used as input data and boundary conditions in 3D and 0D calculations in order to obtain the thermodynamic conditions of the gas in the cylinder during cold starting. The results obtained from the study of two engine configurations -low and high compression ratio- indicate that the threshold in-cylinder temperature is a single temperature of about 415 °C.     

Hydrogeochemische Entwicklung in einem pleistoz?nen Porengrundwasserleiter beeinflusst durch Leckage

At a former industrial site in north-western Germany, the lower Quaternary aquifer was investigated with respect to hydrogeology and hydrogeochemistry. The upper aquifer was contaminated by chlorinated hydrocarbons (CHCs) from a chemical factory and remediation attempts have been carried out for over 10 years. The hydraulic conditions of both aquifers were characterized with hydraulic head measurements in March 2012. In addition, three sampling campaigns in 2009, 2011 and 2012 helped to describe the geochemistry of the lower aquifer. In the lower aquifer downstream of the remediation area, influence of contamination as well as the remediation measures should also be visible. In order to demonstrate leakage from the upper aquifer and to show the development of the geochemical characteristics, a transport and reaction model was developed using PhreeqeC. These simulations strengthen the assumption of a leakage scenario. This leads to unexpected nitrate concentrations, products of degradation of organic substances and signals of former input of waters with high sodium contents. Ion exchange and degradation of organic substances were identified as the most important processes that improve groundwater quality in the lower aquifer downstream of the remediation area.     

Dependence of gold nanoparticle production on pulse duration by laser ablation in liquid media

The dependence on laser fluence and laser pulse duration of size, size distribution and concentration of gold nanoparticles synthesized by laser ablation in liquid media was investigated. It was demonstrated that increasing laser energy from 1 to 5 mJ/pulse enhances the ablation rate by a factor of 100. The behavior of the ablation rate, hence of the nanoparticle concentration, as a function of pulse duration (varied from 40 fs to 200 ps) was found to strongly differ from that in air, which can be explained by photoionization and important losses of laser energy in the femtosecond regime. The optimal pulse duration for maximum ablation rate in liquid media was found to be equal to 2 ps.