A Praxical Solution of the Symbol Grounding Problem

Peer reviewe

Experimental investigation of fuel-cooled combustor: Cooling efficiency and coke formation

Scramjet is an air-breathing engine designed to propel advanced aircrafts in the atmosphere, suitable, according to various studies, to thrust high-speed hypersonic flights (over Mach 5). The thermal protection of vehicles flying at hypersonic velocities is a critical problem; as at supersonic speeds the incoming air is at too high temperature to be used as a coolant, the fuel becomes the only adequate source of cooling for the vehicle. Regenerative cooling is a well-known cooling technique using the fuel as coolant. As the development of regeneratively cooled engines faces many difficulties, an empirical study of this cooling technology and of its complex dynamics is of high interest. In this context, a remotely controlled fuel-cooled combustor, suitable for the experimental analysis of the pyrolysis-combustion coupling characterizing a fuel-cooled combustion chamber when a hydrocarbon propellant is used, has been designed. Tests are realized under both stationary and transient conditions using ethylene as fuel and air as oxidizer. Two operating parameters, i.e. fuel mass flow rate (between 0.010 and 0.040 g.s-1) and equivalence ratio (between 1.0 and 1.5), have been investigated. It has been observed that fuel mass flow rate increases always result in the raise of the heat flux density passing from the combustion gases to the combustor walls. It has been seen that mass flow rate raises between 16 and 20 % lead to increases in the thermal energy evacuated by the fuel-coolant in the range from 30.4 to 48.5 %, depending on equivalence ratio and pressure. The dependence of the cooling system heat exchange efficiency on the two operating parameters has been demonstrated. The consequences of the coking activity of the fuel have also been investigated. For applied interest, a monitoring method for carbon deposits formation has been developed and validated

The digital services act: an analysis of its ethical, legal, and social implications

In December 2020, the European Commission issued the Digital Services Act (DSA), a legislative proposal for a single market of digital services, focusing on fundamental rights, data privacy, and the protection of stakeholders. The DSA seeks to promote European digital sovereignty, among other goals. This article reviews the literature and related documents on the DSA to map and evaluate its ethical, legal, and social implications. It examines four macro-areas of interest regarding the digital services offered by online platforms. The analysis concludes that, so far, the DSA has led to contrasting interpretations, ranging from stakeholders expecting it to be more challenging for gatekeepers, to others objecting that the proposed obligations are unjustified. The article contributes to this debate by arguing that a more robust framework for the benefit of all stakeholders should be defined

AI Risk Assessment: A Scenario-Based, Proportional Methodology for the AI Act

The EU Artificial Intelligence Act (AIA) defines four risk categories for AI systems: unacceptable, high, limited, and minimal. However, it lacks a clear methodology for the assessment of these risks in concrete situations. Risks are broadly categorized based on the application areas of AI systems and ambiguous risk factors. This paper suggests a methodology for assessing AI risk magnitudes, focusing on the construction of real-world risk scenarios. To this scope, we propose to integrate the AIA with a framework developed by the Intergovernmental Panel on Climate Change (IPCC) reports and related literature. This approach enables a nuanced analysis of AI risk by exploring the interplay between (a) risk determinants, (b) individual drivers of determinants, and (c) multiple risk types. We further refine the proposed methodology by applying a proportionality test to balance the competing values involved in AI risk assessment. Finally, we present three uses of this approach under the AIA: to implement the Regulation, to assess the significance of risks, and to develop internal risk management systems for AI deployers

Analysis of Ozone (O3) and Erythemal UV (EUV) measured by TOMS in the equatorial African belt

We presented time series of total ozone column amounts (TOCAs) and erythemal UV (EUV) doses derived from measurements by TOMS (Total Ozone Mapping Spectrometer) instruments on board the Nimbus-7 (N7) and the Earth Probe (EP) satellites for three locations within the equatorial African belt for the period 1979 to 2000. The locations were Dar-es-Salaam (6.8° S, 39.26° E) in Tanzania, Kampala (0.19° N, 32.34° E) in Uganda, and Serrekunda (13.28° N, 16.34° W) in Gambia. Equatorial Africa has high levels of UV radiation, and because ozone shields UV radiation from reaching the Earth’s surface, there is a need to monitor TOCAs and EUV doses. In this paper we investigated the trend of TOCAs and EUV doses, the effects of annual and solar cycles on TOCAs, as well as the link between lightning and ozone production in the equatorial African belt. We also compared clear-sky simulated EUV doses with the corresponding EUV doses derived from TOMS measurements. The TOCAs were found to vary in the ranges 243 DU − 289 DU, 231 DU − 286 DU, and 236 DU − 296 DU, with mean values of 266.9 DU, 260.9 DU, and 267.8 DU for Dar-es-Salaam, Kampala and Serrekunda, respectively. Daily TOCA time series indicated that Kampala had the lowest TOCA values, which we attributed to the altitude effect. There were two annual ozone peaks in Dar-es-Salaam and Kampala, and one annual ozone peak in Serrekunda. The yearly TOCA averages showed an oscillation within a five-year period. We also found that the EUV doses were stable at all three locations for the period 1979−2000, and that Kampala and Dar-es-Salaam were mostly cloudy throughout the year, whereas Serrekunda was mostly free from clouds. It was also found that clouds were among the major factors determining the level of EUV reaching the Earth´s surface. Finally, we noted that during rainy seasons, horizontal advection effects augmented by lightning activity may be responsible for enhanced ozone production in the tropics.publishedVersio

Regulate artificial intelligence to avert cyber arms race

This paper argues that there is an urgent need for an international doctrine for cyberspace skirmishes before they escalate into conventional warfare

Impact of Novel Sorghum Bran Diets on DSS-Induced Colitis.

We have demonstrated that polyphenol-rich sorghum bran diets alter fecal microbiota; however, little is known regarding their effect on colon inflammation. Our aim was to characterize the effect of sorghum bran diets on intestinal homeostasis during dextran sodium sulfate (DSS)-induced colitis. Male Sprague-Dawley rats (N = 20/diet) were provided diets containing 6% fiber from cellulose, or Black (3-deoxyanthocyanins), Sumac (condensed tannins) or Hi Tannin Black (both) sorghum bran. Colitis was induced (N = 10/diet) with three separate 48-h exposures to 3% DSS, and feces were collected. On Day 82, animals were euthanized and the colon resected. Only discrete mucosal lesions, with no diarrhea or bloody stools, were observed in DSS rats. Only bran diets upregulated proliferation and Tff3, Tgfβ and short chain fatty acids (SCFA) transporter expression after a DSS challenge. DSS did not significantly affect fecal SCFA concentrations. Bran diets alone upregulated repair mechanisms and SCFA transporter expression, which suggests these polyphenol-rich sorghum brans may suppress some consequences of colitis

The semantics of untrustworthiness

We offer a formal treatment of the semantics of both complete and incomplete mistrustful or distrustful information transmissions. The semantics of such relations is analysed in view of rules that define the behaviour of a receiving agent. We justify this approach in view of human agent communications and secure system design. We further specify some properties of such relations

Aerobic training and angiogenesis activation in patients with stable chronic heart failure: a preliminary report.

The pathophysiology of chronic heart failure (CHF) involves multiple hystologic and molecular alterations. To determine the effects of physical training on circulating endothelial progenitor cells (EPCs), angiogenesis (angiogenin, angiopoietin-1 and -2, VEGF, Tie-2, SDF-1α) and inflammation (IL-6, CRP), we compared data obtained from 11 CHF pts before and after 3 months aerobic exercise training, to those from 10 non trained CHF pts (CHF-C group, age 64 + 2 years, NYHA 2). At the end of the study, EPCs count and AP-2 serum levels significantly increased in the CHF-TR group. These preliminary data suggest a significant effect of even a short program of physical training on angiogenic activation and endothelial dysfunction

Applying spatial reasoning to topographical data with a grounded geographical ontology

Grounding an ontology upon geographical data has been pro- posed as a method of handling the vagueness in the domain more effectively. In order to do this, we require methods of reasoning about the spatial relations between the regions within the data. This stage can be computationally expensive, as we require information on the location of points in relation to each other. This paper illustrates how using knowledge about regions allows us to reduce the computation required in an efficient and easy to understand manner. Further, we show how this system can be implemented in co-ordination with segmented data to reason abou