A novel framework to improve motion planning of robotic systems through semantic knowledge-based reasoning

The need to improve motion planning techniques for manipulator robots, and new effective strategies to manipulate different objects to perform more complex tasks, is crucial for various real-world applications where robots cooperate with humans. This paper proposes a novel framework that aims to improve the motion planning of a robotic agent (a manipulator robot) through semantic knowledge-based reasoning. The Semantic Web Rule Language (SWRL) was used to infer new knowledge based on the known environment and the robotic system. Ontological knowledge, e.g., semantic maps, were generated through a deep neural network, trained to detect and classify objects in the environment where the robotic agent performs. Manipulation constraints were deduced, and the environment corresponding to the agent’s manipulation workspace was created so the planner could interpret it to generate a collision-free path. For reasoning with the ontology, different SPARQL queries were used. The proposed framework was implemented and validated in a real experimental setup, using the planning framework ROSPlan to perform the planning tasks. The proposed framework proved to be a promising strategy to improve motion planning of robotics systems, showing the benefits of artificial intelligence, for knowledge representation and reasoning in robotics.info:eu-repo/semantics/publishedVersio

Potential biological sources of long chain alkyl diols in a lacustrine system

Long chain alkyl diols (LCDs) have been detected in a range of marine and lacustrine environments, as well as in several algal cultures. However, the identity of the producers, their preferred ecological niche and seasonality are uncertain. We applied a gene-based approach to determine the identity and abundance of Eustigmatophyceae 18S rRNA genes and compared the data with the distribution of LCDs in the water column of Lake Challa (East Africa). Gene-based analysis revealed three known and two novel Eustigmatophyceae groups. Maxima in the number of gene copies and LCD concentration coincided at 9 m water depth, signifying Eustigmatophyceae as important producers of LCDs. In addition, seasonal changes in LCD abundance in sedimenting particles revealed several blooms of LCD producers over the annual cycle

Sea surface temperature variations in the western Mediterranean Sea over the last 20 kyr: A dual-organic proxy (U<super>K'</super>₃₇ and LDI) approach

A high-resolution sea surface temperature (SST) reconstruction of the western Mediterranean was accomplished using two independent, algae-based molecular organic proxies, i.e., the U-37(K) index based on long-chain unsaturated ketones and the novel long-chain diol index (LDI) based on the relative abundances of C-28 and C-30 1,13- and 1,15-diols. Two marine records, from the western and eastern Alboran Sea basin, spanning the last 14 and 20kyr, respectively, were studied. Results from the surface sediments suggest that the two proxies presently reflect seasons with similar SST or simply annual mean SST. Both proxy records reveal the transition from the Last Glacial Maximum to the Holocene in the eastern Alboran Sea with an SST increase of approximately 7 degrees C for U-37(K) and 9 degrees C for LDI. Minimum SSTs (10-12 degrees C) are reached at the end of the Last Glacial Maximum and during the last Heinrich event with a subsequent rapid SST increase in LDI-SST toward the beginning of the Bolling period (20 degrees C), while U-37(K)-SST remains constantly low (similar to 12 degrees C). The Bolling-Allerod period is characterized by a rapid increase and subsequent decrease in U-37(K)-SST, while the LDI-SST decrease continuously. Short-term fluctuations in U-37(K)-SST are probably related to the availability of nutrients and seasonal changes. The Younger Dryas is recorded as a short cold interval followed by progressively warmer temperatures. During the Holocene, the general lower U-37(K)-derived temperature values in the eastern Alboran (by approximately 1.5-2 degrees C) suggest a southeastward cold water migration by the western Alboran gyre and divergence in the haptophyte blooming season between both basins.<br>Key Points<br><list list-type="bulleted" id="palo20073-list-0001"> <list-item id="palo20073-li-0001">High-resolution SST reconstruction is performed in the westernmost Mediterranean <list-item id="palo20073-li-0002">Two algae-based proxies show the temperature evolution for the last 20 kyr <list-item id="palo20073-li-0003">Derived SSTs suggest different growth seasons of alkenone and diol producer

Self-consistent scattering description of transport in normal-superconductor structures

We present a scattering description of transport in several normal-superconductor structures. We show that the related requirements of self-consistency and current conservation introduce qualitative changes in the transport behavior when the current in the superconductor is not negligible. The energy thresholds for quasiparticle propagation in the superconductor are sensitive to the existence of condensate flow ($v_s\neq 0$). This dependence is responsible for a rich variety of transport regimes, including a voltage range in which only Andreev transmission is possible at the interfaces, and a state of gapless superconductivity which may survive up to high voltages if temperature is low. The two main effects of current conservation are a shift towards lower voltages of the first peak in the differential conductance and an enhancement of current caused by the greater availability of charge transmitting scattering channels.Comment: 31 pages, 10 PS figures, Latex file, psfig.sty file is added. To appear in Phys. Rev. B (Jan 97

Phenomenological constraints on SUSY SU(5) GUTs with non-universal gaugino masses

We study phenomenological aspects of supersymmetric SU(5) grand unified theories with non-universal gaugino masses. For large tan beta, we investigate constraints from the requirement of successful electroweak symmetry breaking, the positivity of stau mass squared and the b to s gamma decay rate. In the allowed region, the nature of the lightest supersymmetric particle is determined. Examples of mass spectra are given. We also calculate loop corrections to the bottom mass due to superpartners.Comment: 10 pages, 2 figures (8 eps files), uses REVTeX. Replaced to match the version to be published in PRD: minor corrections and addition

Sa Nitja. Gestió del patrimoni Mediterrani: Resultats de les campanyes de prospecció a la ciutat romana de Sanisera (Es Mercadal - Menorca)

Exemplar dedicat a: Homenatge al Dr. Pere de Palol/

A Milestone in the Chemical Synthesis of Fe3O4 Nanoparticles Unreported Bulklike Properties Lead to a Remarkable Magnetic Hyperthermia

Among iron oxide phases, magnetite Fe3O4 is often the preferred one for nanotechnological and biomedical applications because of its high saturation magnetization and low toxicity. Although there are several synthetic routes that attempt to reach magnetite nanoparticles NPs , they are usually referred as IONPs iron oxide NPs due to the great difficulty in obtaining the monophasic and stoichiometric Fe3O4 phase. Added to this problem is the common increase of size shape polydispersity when larger NPs D gt; 20 nm are synthesized. An unequivocal correlation between a nanomaterial and its properties can only be achieved by the production of highly homogeneous systems, which, in turn, is only possible by the continuous improvement of synthesis methods. There is no doubt that solving the compositional heterogeneity of IONPs while keeping them monodisperse remains a challenge for synthetic chemistry. Herein, we present a methodical optimization of the iron oleate decomposition method to obtain Fe3O4 single nanocrystals without any trace of secondary phases and with no need of postsynthetic treatment. The average dimension of the NPs, ranging from 20 to 40 nm, has been tailored by adjusting the total volume and the boiling point of the reaction mixture. Mössbauer spectroscopy and DC magnetometry have revealed that the NPs present a perfectly stoichiometric Fe3O4 phase. The high saturation magnetization 93 2 A m2 kg at RT and the extremely sharp Verwey transition at around 120 K shown by these NPs have no precedent. Moreover, the synthesis method has been refined to obtain NPs with octahedral morphology and suitable magnetic anisotropy, which significantly improves the magnetic hyperthemia performance. The heating power of properly PEGylated nano octahedrons has been investigated by AC magnetometry, confirming that the NPs present negligible dipolar interactions, which leads to an outstanding magnetothermal efficiency that does not change when the NPs are dispersed in environments with high viscosity and ionic strength. Additionally, the heat production of the NPs within physiological media has been directly measured by calorimetry under clinically safe conditions, reasserting the excellent adequacy of the system for hyperthermia therapies. To the best of our knowledge, this is the first time that such bulklike magnetite NPs with minimal size shape polydispersity, minor agglomeration, and exceptional heating power are chemically synthesize