Recent research on collective adaptive systems and macro-programming has shown the importance of programming abstractions for expressing the self-organising behaviour of ensembles, large and dynamic ...sets of collaborating devices. These generally leverage the interplay between the execution model and the program logic to steer the global-level emergent behaviour of the system. One notable example is the aggregate process abstraction: in an asynchronous round-based computational model, it allows to specify how aggregate-level computations are spawned, take form or spread on a domain of devices, and ultimately quit. Previous presentations of aggregate processes, however, are given in the formal framework of the field calculus, requiring knowledge of its syntax and articulated semantics. To provide a more accessible and language-agnostic presentation of such an abstraction, in this paper we introduce a general formal framework of collective computational processes (CCP). Specifically, as key contribution, we model and describe the programming interface (spawn construct) and dynamics of CCPs on event structures. Furthermore, we also propose novel algorithms for efficient propagation and termination of CCPs, based on statistics on the information speed and a notion of progressive wave-like closure. Crucially, thanks to our theoretical framework, we can provide optimality guarantees for the proposed algorithms, whose performance, superior to the state of the art, is assessed by simulation. Finally, to show applicability of CCPs, we provide a case study of situated service discovery in peer-to-peer networks.
•Collective computational processes (CCP) are abstractions for IoT-like systems.•CCPs model progressive collaborative activities on dynamic ensembles.•Controlling the domain and dynamics of CCPs require distributed algorithms.•Algorithms based on information speed enable optimal CCP propagation/termination.•CCPs can support decentralised service discovery/access.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The vegetated biofiltration systems (VBS), also known as bioretentions or rain gardens, are well-established technology for treatment of urban stormwater and recently greywater, offering multiple ...benefits to urban environments. However, the impact of high ammonium strength wastewater (60 mg/L) on the nitrification process in these systems is not well understood. Hence, a laboratory-based column study was conducted to uncover dominant nitrification mechanisms, based on the learnings from similar onsite wastewater treatment systems. The experimental columns tested the effect of contact time (filter media depth, 150 mm, 300 mm and 700 mm), media oxygenation (active and passive) and alkalinity/pH (marble chips 5 % weight), as well as optimal operational conditions (inflow loading, concentrations, and dissolved oxygen (DO)). All nitrogen species (NH4+, NO3−, NO2−), chemical oxygen demand (COD) and physical parameters (DO, pH, electrical conductivity) were monitored across seven events over thirteen weeks. The results show that dosing with 30 and 60 mg/L of NH4+ resulted in 700 mm sand column depth to perform almost complete nitrification of NH4+ to NO3− (< 90 %), while 300 mm designs achieved partial nitrification of NH4+ to NO2−, likely due to limited contact time and inefficient nitrite oxidizing bacteria activity. Nitrification potential of all designs further supported that appropriate aerobic contact time is necessary for effective nitrification. Inflow concentration of NH4+ and DO did not significantly impact nitrification performance, while reducing daily volume loading reduced NO3− and NO2− leaching. Active and passive aeration and alkalinity buffering did not positively affect ammonium removal. While there is a potential to apply both nitrification-denitrification and anammox processes to future VBS design, further understanding of aeration and alkalinity on microbially driven nitrification processes is needed.
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•Complete nitrification of 60 mg/L NH4+ was achieved in 700 mm deep sand columns.•Limited by contact time, partial nitrification to NO2− was seen in 300 mm columns.•Inflow concentration and DO change did not significantly affect nitrification.•Added aeration and alkalinity buffer somewhat hindered nitrification potential.•Nitrification-denitrification and anammox processes show promise in VBS application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The spatial distribution of infrastructure plays a key role in shaping the levels of social acceptance in future energy systems. Here, I evaluate the cost impact and changes in the system composition ...when development of infrastructure is more evenly shared among countries and regions in a fully renewable European power system. I deliberately deviate from the resource-induced cost optimum towards more equitable and self-sufficient solutions in terms of power generation. The analysis employs the open optimization model PyPSA-Eur. I show that purely cost-optimal solutions lead to very inhomogeneous distributions of capacities, but more uniform expansion plans can be achieved on a national level at little additional expense below 4%. However, completely autarkic solutions, without power transmission, appear much more costly across a variety of technology cost assumptions.
•Cost-optimal solutions lead to inhomogeneous distribution of capacities.•More regionally equitable solutions increase costs by merely 4% on a national level.•Autarkic solutions without power transmission are much more costly but feasible.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The development of microbial source tracking methods has resulted in an array of genetic faecal markers for assessing human health risks posed from surface water pollution. However, their use as ...performance metrics at wastewater treatment plants (WWTPs) has not been explored extensively. Here we compared three Bacteroides (HF183, HumM2, AllBac) and two E. coli (H8, RodA) genetic markers for summer and winter performance monitoring at twelve small rural (<250 PE) and three larger WWTPs in NE England. Small WWTPs are of interest because they are poorly understood and their impact on surface water quality may be underestimated. Overall, genetic marker data showed significant differences in treatment performance at smaller versus larger WWTPs. For example, effluent abundances of HF183 and HumM2 were significantly higher in smaller systems (p = 0.003 for HumM2; p = 0.02 for HF183). Genetic markers also showed significant differences in performance between seasons (p < 0.01, n = 120), with human-specific markers (i.e., HF183, HumM2, H8) being generally better for summer WWTP monitoring. In contrast, Bacteroides markers were much more suitable for winter monitoring, possibly because the E. coli markers are less sensitive to differences in temperature and sunlight conditions. Overall, Bacteroides markers best described WWTP treatment performance across all samples, although seasonal differences suggest caution is needed when markers are used for performance monitoring. Genetic markers definitely provide rapid and new information about WWTP performance, but more spatially diverse studies are needed to refine their use for routine WWTP monitoring.
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•Removal rates of genetic faecal markers are compared between small vs large WWTPs.•Performance was significantly poorer lower in small WWTPs, especially reliability.•Human-specific genetic markers describe performance better in summer operations.•Bacteroides markers are generally better across seasons, especially HF183 and HumM2.•Genetic markers are a useful addition to WWTP monitoring, especially for small systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The results of a comparative study of two different technological solutions applicable to decentralised domestic wastewater treatment systems are presented. A hybrid reactor with activated sludge and ...mobile biofilm carriers moving in wastewater is one of them, and an innovative quasi-technical combination of a biological reactor with a sprinkled bed filled with sintered clay granules, followed in the process line by an innovative slope type filtration bed, is the other one. The study has shown a significant advantage of filter bed installations in functional quality, expressed in low values of indicators and pollutant concentrations. In the comparison of technological reliability and probability of exceeding the requirement values of BOD5 = 40 mg/L, Facility 1 achieved technological reliability of 70% and probability of exceeding was 23%. Technological reliability of Facility 2 in this component was 100% and P = 0%. Both facilities presented 100% technological reliability in the COD indicators, with zero probability of exceeding the required value of 150 mg/L. The reliability of TSS removal was similarly high in both facilities: 91% and 100%. The higher functional quality of Facility 2 was evident in TN and PO4–P parameters, where the period of its operation with exceeded values did not exceed 20% and 13%, respectively, with a low probability of exceeding the value of 18% and 2.5%, respectively. However, Facility 1 was unreliable in this regard in 90% and 84%, with a very high probability of exceeding the required values of these parameters: 88% and 72%. This facility does not meet the required criteria in this respect and may cause a risk to the aquatic environment if wastewater is discharged directly into open watercourses, or if it enters shallow groundwater. The use of a suitable, biologically active soil-plant receiver can eliminate this risk.
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•Removal efficiency of organic pollutants is lower in activated sludge plants than in biological beds.•Removal efficiency of nutrient compounds is lower in activated sludge plants than in biological beds.•Cost of wastewater treatment in biological treatment plants is significantly lower than in activated sludge plants.•For the treatment of small volumes of wastewater (eg from a single building), sprinklered biological beds are recommended.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Reclaimed water can achieve 100 % tap water savings when used for irrigation.•Decentralized systems can reduce a resident's carbon footprint by 20–23 %.•Capital costs are about 98 % higher, but ...operational costs are reduced by 66–77 % in decentralised systems.•Decentralised systems are cost-effective provided energy and reclaimed water are valorised.
The planning and construction of large-scale wastewater infrastructure, such as sewerage networks and wastewater treatment plants, is undertaken by the public sector or by publicly regulated monopolies. Only on smaller scales can infrastructure be managed by private companies or through local collective initiatives. Within this framework of water cycle management, there is an increasing movement of the population towards cities where economic activity is concentrated. This scenario is particularly pronounced in certain regions of the world and makes it necessary to rethink whether decentralised treatment offers a way of ensuring the servicing of wastewater treatment in new urban developments, alleviating pressure on facilities that are at the limit of their capacity.
In this study four systems were evaluated: two centralised and two decentralised configurations, from an environmental and economic perspective, posing as working hypothesis how different wastewater treatment schemes influence the carbon footprint of the population living in a neighbourhood. The analysis of the results identifies that the decentralised systems present a reduction in the carbon footprint of residents of around 20–23 % depending on the technology considered. In addition, reclaimed water can meet the water quality requirements for irrigation of the green areas in the neighbourhood. Although decentralised systems have higher construction costs, they can be amortised due to lower energy consumption, so the payback time is estimated to be 8–9 years, lower than that of centralised systems. Considering the problems associated with changing and replacing existing networks, decentralised wastewater treatment systems is especially recommended for new dwelling developments, based on its environmental and economic indicators.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The rise in milk adulteration and contamination, fraud incidents and improper handling necessitates effective traceability systems in the Indian dairy industry. Thus, this review investigates current ...trends, associated challenges, traceability and its fundamental applications to address food safety and quality issues. The paper covers the evolution of milk adulteration and contamination detection techniques from conventional to emerging. Such information and analytical technologies can improve transparency and safety in the dairy industry by implementing effective traceability systems. This review will explore the challenges and future opportunities associated with the current situation in the Indian dairy industry.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•There are both benefits and risks associated with rainwater harvesting.•Mosquitoes in rainwater harvesting systems is a serious problem.•In our study we found that more than 20% of tanks had ...mosquitoes in them.•We have explored data to see prevalence of mosquitoes.•We show that risk mitigation is possible but requires some effort.
Rainwater harvesting in residential homes is emerging as an important complement to centralized water supplies in urban centres around the world. Domestic rainwater harvesting systems provide a variety of benefits for water management and contribute to sustainable and integrated urban water management. There are however risks associated with rainwater harvesting that requires appropriate mitigation. One such risk is that systems can become breeding grounds for mosquitoes. This can constitute a significant health risk through the spread of mosquito-borne diseases (i.e. arbovirus and malaria). This paper explores the extent to which mosquitoes breed in rainwater harvesting systems as well as the effectiveness of different risk mitigation actions. Data were sourced from a large-scale domestic rainwater tank inspection survey undertaken in Melbourne and were analysed using simple Bayesian Network models. The observed rate of mosquito breeding was too high and was identified as a serious concern for health officials and water managers. The most common access routes into the tank system were found to be through the tank inlet or overflow. By exploring different system set-ups it was found that in order to mitigate the risk of mosquito breeding in tanks, all potential access routes must be adequately sealed. The complete eradication of mosquitos in rainwater tanks, however, may need further investigation, as 4% of systems with adequate protection at the inlet and overflow were still found to have mosquitoes in them.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The widespread adoption of the new generation of decentralised architectures, leveraged by blockchain and decentralised file storage (DFS) systems, enables a myriad of new applications and ...opportunities. Nevertheless, their remarkable features, namely auditability, availability and, among all, immutability, do not come without a cost. In this article, we examine blockchain and the most widely used DFS systems and discuss their main challenges and opportunities, with special regard to their immutability and its impact on their GDPR compliance. A description of current and prospective threats is also provided, along with an analysis of the features that each threat exploits. In addition, we discuss several measures to address the identified threats, and we provide a fertile common ground for further research.
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