Novelty search for soft robotic space exploration

The use of soft robots in future space exploration is still a far-fetched idea, but an attractive one. Soft robots are inherently compliant mechanisms that are well suited for locomotion on rough terrain as often faced in extra-planetary environments. Depending on the particular application and requirements, the best shape (or body morphology) and locomotion strategy for such robots will vary substantially. Recent developments in soft robotics and evolutionary optimization showed the possibility to simultaneously evolve the morphology and locomotion strategy in simulated trials. The use of techniques such as generative encoding and neural evolution were key to these findings. In this paper, we improve further on this methodology by introducing the use of a novelty measure during the evolution process. We compare fitness search and novelty search in different gravity levels and we consistently find novelty-based search to perform as good as or better than a fitness-based search, while also delivering a greater variety of designs. We propose a combination of the two techniques using fitness-elitism in novelty search to obtain a further improvement. We then use our methodology to evolve the gait and morphology of soft robots at different gravity levels, finding a taxonomy of possible locomotion strategies that are analyzed in the context of space-exploration

SLA-mechanisms for electricity trading under volatile supply and varying criticality of demand (Extended Abstract)

The increasing adoption of renewable power generation makes volatile quantities of electricity available, the delivery of which cannot be guaranteed, if sold. However, if not sold, the electricity might need to be curtailed, thus foregoing potential profits. In this paper we adapt service level agreements (SLAs) for the future smart electricity grid, where generation will primarily depend on volatile and istributed renewable power sources, and where buyers' ability to cope with uncertainty may vary significantly. We propose a contracting framework through SLAs to allocate uncertain power generation to buyers of varying preferences. These SLAs comprise quantity, reliability and price. We define a characterization of the value degradation of tolerant and critical buyers with regards to the uncertainty of electricity delivery (generalizing the Value of Lost Load, VoLL). We consider two mechanisms (sequential second-price auction and VCG) that allocate SLAs based on buyer bids. We further study the incentive compatibility of the proposed mechanisms, and show that both mechanisms ensure that no buyer has an incentive to misreport its valuation. We experimentally compare their performance and demonstrate that VCG dominates alternative allocations, while vastly improves the efficiency of the proposed system when compared to a baseline allocation considering only the VoLL. This article lays the ground work for distributed energy trading under uncertainty, thereby contributing an essential component to the future smart grid

A multi-scale energy demand model suggests sharing market risks with intelligent energy cooperatives

In this paper, we propose a multi-scale model of energy demand that is consistent with observations at a macro scale, in our use-case standard load profiles for (residential) electric loads. We employ the model to study incentives to assume the risk of volatile market prices for intelligent energy cooperatives at different aggregation scales of energy consumption. Next to scale, we investigate the benefits of demand response, more precisely intelligent scheduling of time-shiftable electric processes, and virtual storage intraday and between days. Results show that the increasing electrification and introduction of flexibilities (electric vehicles, thermal applications, storage, etc.) is going to make market participation viable for smaller groups of consumers. Retailers may thus introduce innovative tariffs for intelligent energy cooperatives to share the risk of volatility in wholesale markets for electricity

Forecast-based mechanisms for demand response

We study mechanisms to incentivize demand response in smart energy systems. We assume agents that can respond (reduce their demand) with some probability if they prepare prior to the real-ization of the demand. Both preparation and response incur costs to agents. Previous work studies truthful mechanisms that select a minimal set of agents to prepare and respond such that a fixed demand reduction target is achieved with high probability. In this work we additionally consider the balancing responsibility of a retailer under a given demand forecast and imbalance price: The retailer is responsible to purchase additional reserve capacity at a high imbalance price to cover any excess in the demand. In this extended setting we study mechanisms that request only a subset of prepared agents to respond since the reduction target depends on the realization of the demand: We propose: (i) a sequential mechanism that in each round embeds a second-price auction and is truthful under some mild assumptions for the setting, and (ii) a truthful combinatorial mechanism that runs in polynomial time and uses VCG payments. We show that both mechanisms guarantee non-negative utility in expectation for both agents and the retailer (mechanism), and can further be used for simultaneous downward and upward flexibility. Last, we verify our theoretical findings in an empirical evaluation over a wide range of mechanism parameters

Agent Interactions & Mechanisms in Markets with Uncertainties: Electricity Markets in Renewable Energy Systems

Electricity consumption is highly correlated with the level of human development,which alongside electrification is expected to significantly increase global demandfor electricity in the coming decades. In current electricity systems, most of the electricity is generated by large fossil-fuel power plants on-demand and it is distributed by centrally-managed electricity grids. The increasing demand for electricity, however, should not go hand in hand with the simultaneous intensification of fossil-fuel mine and use, which is a driving cause of rising average temperatures on Earth’s surface. Natural sources such as the sun and wind are expected to replace conventional sources of electricity, such as coal and gas power plants, in the near future, providing a key measure to address climate change and abate the effects of global warming. However, the intermittent and distributed nature of renewable electricity sources requires a redesign of conventional electricity grids that were originally designed following a top-down approach.Intelligent Electrical Power Grid

Construction of a simple optical sensor based on air stable lipid film with incorporated urease for the rapid detection of urea in milk

This work describes the construction of a simple optical sensor for the rapid, selective and sensitive detection of urea in milk using air stable lipid films with incorporated urease. The lipid film is stabilized on a glass filter by polymerization using UV (ultra-violet) radiation prior its use. Methacrylic acid was the functional monomer, ethylene glycol dimethacrylate was the crosslinker and 2,2'-azobis-(2-methylpropionitrile) was the initiator. Urease is incorporated within this mixture prior to the polymerization. The presence of the enzyme in these films quenched this fluorescence and the colour became similar to that of the filters without the lipid films. A drop of aqueous solution of urea provided a "switching on" of the fluorescence which allows the rapid detection of this compound at the levels of 10-8M concentrations. The investigation of the effect of potent interferences included a wide range of compounds usually found in foods and also of proteins and lipids. These lipid membranes were used for the rapid detection of urea in milk. © 2010 Elsevier B.V

Spectroscopic studies on the anticancer antibiotic Altromycin H and the interaction with copper(II) ions

The antitumor antibiotic Altromycin H was studied using electronic absorption (UV-Vis.) and circular dichroism (CD) spectroscopy. The dissociation constants of the phenolic groups on C(5) and C(11) were estimated as pK 1 = 6.7 and pK 2 = 11.8 at 25°C, respectively, and a complete assignment of the CD and UV-Vis. bands is proposed. The interaction of Cu(II) ions with the Altromycin H has been also investigated by UV-Vis., CD and electron paramagnetic resonance (EPR) spectroscopy. A pH depended stepwise complex formation was observed. At pH < 4 no copper-Altromycin H interactions were detected. At the 4 < pH < 8 the Cu(II) ions coordinate to Altromycin H via the C(4)O and C(5)OH groups atoms of the chromophore ring and the [Cu(AltroH) 2] complex (formation constant, K f, 4.00 ± 0.9 × 10 11 M -2 at 25°C) is the predominant species. In alkaline solution the hydroxo-bridged complex, [Cu(OH)(AltroH)] 2, is proposed to be as the unique present species. © 2004 Elsevier Inc. All rights reserved

Polymers with Amino Acids in Their Side Chain: Conformation of Polymers Derived from Glycylglycine and Phenylalanine

Two polymethacrylamides bearing glycylglycine (PGlyGly) and phenylalanine (PPhe) in the side chain were synthesized by free radical polymerization of the corresponding monomers (general formulas: -[CH2-C(CH3)-CO-NH-CH2-CO-NH-CH2-COOH]-n and -[CH2-C(CH3)-CO-NH-CH(COOH)-CH2-C6H5]-n, respectively). PGlyGly behaves as a normal polyelectrolyte in relation with its hydrophilic nature. On the contrary PPhe takes a compact conformation in water. The free enthalpy of stabilization of this conformation is high as revealed by potentiometric titrations. The influence of some additives (metal ion, urea, organic solvent) on the compact conformation and the pH-induced conformational transition was investigated. It was concluded that the main factor responsible for the existence of this structure consists of hydrophobic domains with nonpolar interactions between the aromatic side chains. © 1994, American Chemical Society. All rights reserved