Semilogarithmic Nonuniform Vector Quantization of Two-Dimensional Laplacean Source for Small Variance Dynamics

In this paper high dynamic range nonuniform two-dimensional vector quantization model for Laplacean source was provided. Semilogarithmic A-law compression characteristic was used as radial scalar compression characteristic of two-dimensional vector quantization. Optimal number value of concentric quantization domains (amplitude levels) is expressed in the function of parameter A. Exact distortion analysis with obtained closed form expressions is provided. It has been shown that proposed model provides high SQNR values in wide range of variances, and overachieves quality obtained by scalar A-law quantization at same bit rate, so it can be used in various switching and adaptation implementations for realization of high quality signal compression

Dilute magnetic semiconductor quantum-well structures for magnetic field tunable far-infrared/terahertz absorption

The design of ZnCdSe–ZnMnSe-based quantum wells is considered, in order to obtain a large shift of the peak absorption wavelength in the far infrared range, due to a giant Zeeman splitting with magnetic field, while maintaining a reasonably large value of peak absorption. A triple quantum-well structure with a suitable choice of parameters has been found to satisfy such requirements. A maximal tuning range between 14.6 and 34.7 meV is obtained, when the magnetic field varies from zero to 5 T, so the wavelength of the absorbed radiation decreases from 85.2 to 35.7 μm with absorption up to 1.25% at low temperatures. These structures might form the basis for magnetic field tunable photodetectors and quantum cascade lasers in the terahertz range

Development of a leakage target setting approach for South Korea based on Economic Level of Leakage

Published13th Computer Control for Water Industry Conference, CCWI 2015Leakage has become a crucial issue that needs to be addressed effectively by water suppliers in terms of economic management of water systems. A target setting method based on the ELL (Economic Level of Leakage) calculation is proposed in this paper. The methodology applied is developed specifically for the South Korean context to select a minimum achievable level of NRW (Non-Revenue Water) and verify the appropriateness of the current target within existing financial constraints by using limited available data. This approach is focused on the derivation of the NRW control cost curve by using the newly developed cumulative method that minimizes data fluctuation and enhances the cost curve reliability. This has been applied to a case study by using data collected from the water supplier information system. The results obtained in this case study show significant outcomes in respect of both identification of an economically optimal target and prevention of unnecessary investment to meet this aim. This advance in leakage management allows water suppliers to select a rational target and manage their system economically and efficiently.This work has been funded and supported by K-water which is the public water company in South Kore

Magnetic field tunable terahertz quantum well infrared photodetector

A theoretical model and a design of a magnetic field tunable CdMnTe/CdMgTe terahertz quantum well infrared photodetector are presented. The energy levels and the corresponding wavefunctions were computed from the envelope function Schr¨odinger equation using the effective mass approximation and accounting for Landau quantization and the giant Zeeman effect induced by magnetic confinement. The electron dynamics were modeled within the self-consistent coupled rate equations approach, with all relevant electron-longitudinal optical phonon and electron-longitudinal acoustic phonon scattering included. A perpendicular magnetic field varying between 0 T and 5 T, at a temperature of 1.5 K, was found to enable a large shift of the detection energy, yielding a tuning range between 24.1 meV and 34.3 meV, equivalent to 51.4 μm to 36.1 μm wavelengths. For magnetic fields between 1 T and 5 T, when the electron population of the QWIP is spin-polarized, a reasonably low dark current of ≤1.4×10–² A/cm² and a large responsivity of 0.36−0.64 A/W are predicted

On the coherence/incoherence of electron transport in semiconductor heterostructure optoelectronic devices

This paper compares and contrasts different theoretical approaches based on incoherent electron scattering transport with experimental measurements of optoelectronic devices formed from semiconductor heterostructures. The Monte Carlo method which makes no a priori assumptions about the carrier distribution in momentum or phase space is compared with less computationally demanding energy-balance rate equation models which assume thermalised carrier distributions. It is shown that the two approaches produce qualitatively similar results for hole transport in p-type Si1-xGex/Si superlattices designed for terahertz emission. The good agreement of the predictions of rate equation calculations with experimental measurements of mid- and far-infrared quantum cascade lasers, quantum well infrared photodetectors and quantum dot infrared photodetectors substantiate the assumption of incoherent scattering dominating the transport in these quantum well based devices. However, the paper goes on to consider the possibility of coherent transport through the density matrix method and suggests an experiment that could allow coherent and incoherent transport to be distinguished from each other

Effectiveness of smart-meter based consumption feedback in curbing household water use: Knowns and unknowns

This is the author accepted manuscript. The final version is available from the American Society of Civil Engineers via the DOI in this record.Adaptive approaches are required to counteract the mounting threats to water security. Demand management will feature centrally in such adaptation. The increase in use of smart meter technology offers an improved way for utilities to gauge consumer demand and to supply consumers with consumption feedback in (near) real-time. Such feedback can decrease the discrepancies between perceived and actual water usage. In contrast to the energy sector, however, where the advantages associated with smart meter consumption feedback are extensively documented, few studies have focused on the usefulness of such feedback when it comes to managing water consumption. This review assesses the evidence base for the effectiveness of water usage feedback technology in encouraging water conservation. The review highlights the potential value of high-granular smart-meter feedback technology in managing domestic water consumption. Findings from the papers included in this review (N = 21) indicate that feedback was associated with decreases of between 2.5% and 28.6% in water use, with an average of 12.15% (SD = 8.75). A single paper reported a 16% increase in consumption associated with smart-meter feedback. The benefits for water utilities are highlighted, but the costs for utilities need to be considered further. Overall, more work is needed to conclusively pinpoint the most effective type of feedback in terms of information content and granularity, frequency of delivery and medium, and how water consumption is linked to energy consumption. This information is needed to make concrete recommendations to the water industry about the costs and benefits of investment in smart metering and consumer feedback.This research received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under the iWIDGET project, grant agreement no. 318272. An earlier version of this paper was published in the conference proceedings of the 2014 Water Distribution Systems Analysis Conference (Sonderlund et al., 2014, Procedia Engineering, 89, 990-997)

Optimising wastewater treatment solutions for the removal of contaminants of emerging concern (CECs): A case study for application in India

This is the author accepted manuscript. The final version is available from IWA Publishing via the DOI in this record.The aim of this study was to produce optimal wastewater treatment solutions to calculate the removal of different CECs found in developing countries. A new methodology was developed for a decision support tool (WiSDOM), which focuses on producing treatment solutions suited to treating water for reuse to Indian Water Quality Standards. WiSDOM-CEC analyses the removal of CECs through different treatment solutions and was also used to evaluate the performance of each treatment train solution in terms of removal of conventional pollutants using multi-objective optimisation and multi criteria decision analysis. Information was collected on different CECs across different regions of India, and the removal of eighteen different CECs through 42 wastewater treatment unit processes for five different regions of India was analysed. Comparisons between similar categories of CECs, such as non-steroidal anti-inflammatory showed that emerging contaminants all react differently to individual treatment options. For example, the removal of Ibuprofen (IBP) and Naproxen (NPX) varied from >80% and 0%, respectively, for a solution in Karnataka involving sedimentation, submerged aerated filter, ultra-filtration and Nano filtration. In Tamil Nadu results ranged from 36.8% to 72% for Diclofenac, 10.7% to 66.5% for IBP and 0% for NPX.European CommissionNatural Environment Research Council (NERC)Engineering and Physical Sciences Research Council (EPSRC

Leak detection and localization based on search space reduction and hydraulic modelling

This is the final version. As published in 2018 WDSA / CCWI Joint Conference Proceedings, available online via the link in this record.Reducing the cost and time required to isolateleakages occurring in Water Distribution Networks (WDNs) is the main taskfor resilientand sustainable management of these systems. Thepaper presents a systematicmodel-based leak detection and localization frameworkusing optimization. Theapproach prerequisites a well calibrated WDNhydraulic model. The leakage localization model splits into two stages: (a) the search reduction stage where the number of decision variables and the range of possible valuesare reduced, and (b) the leak detection and localization stage for isolating the fault. The leakage localizationmethod is formulated to optimize the leakage node locations and their associated emitter coefficients,such that the differences between the model predicted and the field observed values for pressure and flow are minimized. The optimization problem is solved by using a non sorting genetic algorithm. Areal case from a UK system is presented with the outcome showingthat the method reducesthe leak search space within 10% of the WDN, while contributing to earlier leakage hotspot detection and localization. The frameworkfor predicting leakage hotspots can be effective despite the recognized challenges of model calibration and the physical measurement limitations from the collected pressure and flow data.Engineering and Physical Science Research Council (EPSRC

Emerging pollutants in developing countries: Optimising sustainable treatment solutions

This is the author accepted manuscriptOver the past decade the research surrounding the occurrence, source, fate and removal of emerging pollutants has been increasing. The aim of this study was to create an add-on program which analyses the removal of emerging pollutants, to an existing decision support tool (WiSDOM). The tool was also used to evaluate the performance of each optimal solution in terms of removal of conventional pollutants using Multi Objective Genetic Algorithms and Multi Criteria Decision Analysis. Information was collated regarding minimum and maximum concentrations of emerging pollutants for surface water, groundwater, untreated wastewater, drinking water and treated wastewater. This information was used to populate an Excel Spreadsheet Program (ESP) which analysed the removal efficiencies of 13 different emerging pollutants for 42 wastewater treatment unit processes. The ESP is incorporated into the WiSDOM tool to allow the tool to calculate the removal of emerging pollutants. Three main scenarios were created to test the application of the tool and ESP. Scenario 1 focussed on the removal of emerging pollutants from from areas effected by tourism at different scales. Scenario 2 looked at the treatment suited for the removal of emerging pollutants from different socio-economic regions. Lastly, Scenario 3 looked at removing emerging pollutants from hospital and industrial wastewater. The scenarios were focused on wastewater treatment in India and investigated the removal of 13 emerging pollutants commonly found in India.Engineering and Physical Sciences Research Council (EPSRC)European CommissionNatural Environment Research Council (NERC

Organic Lamb Meat Production in Serbia Based on Autochthonous Zackel Breed: Opportunities and Challenges

The global growing tendency of lamb and mutton meat production has been emphasized. The fastest growing meat production industry on a global level is lamb and mutton meat production. Lamb meat production increase is primarily based on genetic improvement of sheep breeds, reproduction management and disease reduction. The new Strategy for Agriculture and Rural Development in Serbia from 2014 to 2024 defines goals and priorities for further development of agriculture. One of priority topics is the promotion of organic production. Organic lamb production is a great opportunity for rural regions development. Botanical composition analyses, as well as plants nutrition value, have shown that natural resources of regions in Serbia have great potentials for organic lamb production. Basic principles of organic production promote well adapted, autochthonous breeds. Various types of Zackel sheep are important genetic resources, evolutionary adapted on specific conditions and extreme climate. The study evaluated the value of various types of Zackel sheep populations in the regions where they are traditionally reared with special emphasis on some traits such as health status and robustness, important for organic production. Disease frequency analysis in different Zackel type populations has shown that gastrointestinal parasitic infections represent the main health problem in sheep farming. The introduction of veterinary medicine standards in organic sheep production is a great challenge. Considering that conventional prevention and medication are forbidden in organic production, veterinary control of parasitic infections is not satisfying. Our investigations are focused on preventive measure and genetic resistance/tolerance to parasitic infections of various types of Zackel sheep as very important for organic lamb production