Forgetting in Answer Set Programming with Anonymous Cycles

FORGET (PTDC/CCI-INF/32219/2017). NOVA LINCS (UID/CEC/04516/2019).It is now widely accepted that the operation of forgetting in the context of Answer Set Programming [10, 18] is best characterized by the so-called strong persistence, a property that requires that all existing relations between the atoms not to be forgotten be preserved. However, it has been shown that strong persistence cannot always be satisfied. What happens if we must nevertheless forget? One possibility that has been explored before is to consider weaker versions of strong persistence, although not without a cost: some relations between the atoms not to be forgotten are broken in the process. A different alternative is to enhance the logical language so that all such relations can be maintained after the forgetting operation. In this paper, we borrow from the recently introduced notion of fork [1] – a conservative extension of Equilibrium Logic and its monotonic basis, the logic of Here-and-There – which has been shown to be sufficient to overcome the problems related to satisfying strong persistence. We map this notion into the language of logic programs, enhancing it with so-called anonymous cycles, and we introduce a concrete syntactical forgetting operator over this enhanced language that we show to always obey strong persistence.publishe

Advanced Material Models for Stamping of AW 5754 Aluminum Alloy

Predictions by numerical simulations are strongly influenced by availability and reliability of input data. In the most used computational models, the material behavior during deformation is described only by static tensile test in combination with Lankford coefficients of anisotropy. However, for some specific materials like highly anisotropic aluminum alloys, such description of material behavior is insufficient and, in many cases, the calculated results are not in good agreement with the measured ones. In this paper, the implementation of advanced material model for deep-drawing process to explicit FE code and the procedure of measurement of the most important input material data for calculations on the aluminum alloy AW 5754 are discussed. Results of the numerical simulation are compared with the experimental ones and exhibit a close correlation

Experimental and Numerical Analysis of Springback Behavior of Aluminum Alloys

Presented work deals with springback behavior of two different aluminum alloys, one falling into 5th series (AW-5754 H22) with a thickness of 0.8 mm and other from 6th series (AW-6082 T6) with 1.0 mm thickness. These materials are used for their various applications and hardening process. The springback behavior was investigated by U-bending test. Bending tool was graduated jig with rollers and experiment was performed on R11 and R17 radii. The first series of specimens were oriented in a parallel direction and the other in a direction perpendicular to the rolling direction. Experimental results were measured with MATLAB measuring method and compared with finite element calculation carried out in PAM-STAMP. Influence of different yield functions was also examined.Рассматривается характеристика упругой отдачи двух различных алюминиевых сплавов: AW-5754 H22 толщиной 0,8 мм, принадлежащего к 5-й серии, и AW-6082 T6 толщиной 1,0 мм, принадлежащего к 6-й серии. Эти материалы используются для разнообразного применения, включая процесс упрочнения. Характеристика упругой отдачи исследовалась при испытаниях на U-образный изгиб. В качестве гибочного инструмента использовалось приспособление с роликами, и эксперимент проводился на радиусах R11 и R17. Одна группа образцов была ориентирована в направлении, параллельном направлению прокатки, другая в перпендикулярном. Экспериментальные результаты, полученные с использованием программного комплекса MAТLAB, сравнивались с расчетом методом конечных элементов с помощью программы PAM-STAMP. Исследовалось также влияние различных функций текучести

Is Power Grasping Contact Continuous or Discrete?

During power grasp, the number of local force maxima reflects either the central nervous system's preferential use of particular hand regions, or anatomical constraints, or both. Previously, both bimodal and trimodal force maxima have been hypothesized for power grasp of a cylindrical handle. Here we measure the number of local force maxima, with a resolution of 4.8 degrees, when performing pushing and pulling efforts in the plane perpendicular to the cylinder's long axis. Twelve participants produced external forces to eight targets. The number of contacts was defined as the number of local maxima exceeding background variance. A minimum of four and a maximum of five discrete contacts were observed in all subjects at the distal phalanges and metacarpal heads. We thus reject previous hypotheses of bimodal or trimodal force control for cylindrical power grasping. Since we presently observed only 4-5 contacts, which is rather low considering the hand's kinematic flexibility in the flexion plane, we also reject hypotheses of continuous contact, which are inherent to current grasping taxonomy. A modification to current grasping taxonomy is proposed wherein power grasp contains separate branches for continuous and discrete contacts, and where power and precision grasps are distinguished only by grasp manipulability.ArticleJOURNAL OF APPLIED BIOMECHANICS. 29(5):554-562 (2013)journal articl

An indoor test methodology for solar-powered wireless sensor networks

Repeatable and accurate tests are important when designing hardware and algorithms for solar-powered wireless sensor networks (WSNs). Since no two days are exactly alike with regard to energy harvesting, tests must be carried out indoors. Solar simulators are traditionally used in replicating the effects of sunlight indoors - however, solar simulators are expensive, have lighting elements that have short lifetimes, and are usually not designed to carry out the types of tests that hardware and algorithm designers require. As a result, hardware and algorithm designers use tests that are inaccurate and not repeatable (both for others and also for the designers themselves). In this article we propose an indoor test methodology which does not rely on solar simulators. The test methodology has its basis in astronomy and photovoltaic (PV) cell design. We present a generic design for a test apparatus which can be used in carrying out the test methodology. We also present a specific design which we use in implementing an actual test apparatus. We test the efficacy of our test apparatus and, to demonstrate the usefulness of the test methodology, perform experiments akin to those required in projects involving solar-powered WSNs. Results of the said tests and experiments demonstrate that the test methodology is an invaluable tool for hardware and algorithm designers working with solar-powered WSNs

Модель оценивания уровня опасности ситуаций в задачах функционирования сложных объектов

Запропоновано модель оцінювання інформаційного забезпечення особи, що приймає рішення (ОПР), яка ґрунтується на дослідженні якісних показників інформованості: повноти, достовірності та своєчасності інформованості ОПР. На основі цих показників сформовано рівень небезпеки ситуації під час функціонування складних об’єктів. Для реалізації моделі використовувалися методи однопараметричної класифікації з операціями перетину нечітких множин і сильного перетину, методи інтервальної класифікації з операціями об'єднання і перетину нечітких множин, а також з операціями сильного об'єднання і перетину нечітких множин. Запропоновані методи дозволяють класифікувати ситуації для інформування ОПР про обгрунтованість і безпеку прийняття рішення за наявного інформаційного забезпечення. Розроблена модель базується на дослідженні якісних показників інформованості ОПР і може бути застосована для оцінювання рівня небезпеки ситуацій в задачах функціонування складних об'єктів.The model of information support estimation of the decision maker (DM) based on a study of qualitative indicators of informedness, which characterizes the completeness, accuracy and timeliness of DM informedness , is presented. On the basis of these characteristics the level of danger situations in the operation of complex objects is formed. In implementing the model are used the methods of one-parameter classification with operations of fuzzy sets and strong intersections, as well as methods of interval classification with the operations of union and intersection of fuzzy sets, and also with operations of strong union and intersection of fuzzy sets. The proposed methods allow classifying the situation to inform DM about the validity and security of the decision with the available information support. The proposed model is based on a study of qualitative characteristics of informedness of DM and can be used to estimate the level of danger situations in the problems of the complex objects operation.Предложена модель оценивания информационного обеспечения лица, принимающего решения (ЛПР), основанная на исследовании качественных показателей информированности: полноты, достоверности и своевременности информированности ЛПР. На основе этих показателей сформирован уровень опасности ситуаций при функционировании сложных объектов. Для реализации модели использовались методы однопараметрической классификации с операциями пересечения нечетких множеств и сильного пересечения, методы интервальной классификации с операциями объединения и пересечения нечетких множеств, а также с операциями сильного объединения и пересечения нечетких множеств. Предложенные методы позволяют классифицировать ситуации для информирования ЛПР об обоснованности и безопасности принятия решения при имеющемся информационном обеспечении. Разработанная модель базируется на исследовании качественных показателей информированности ЛПР и может быть применена для оценивания уровня опасности ситуаций в задачах функционирования сложных объектов

The scope of application of incremental rapid prototyping methods in foundry engineering

Abstract The article presents the scope of application of selected incremental Rapid Prototyping methods in the process of manufacturing casting models, casting moulds and casts. The Rapid Prototyping methods (SL, SLA, FDM, 3DP, JS) are predominantly used for the production of models and model sets for casting moulds. The Rapid Tooling methods, such as: ZCast-3DP, ProMetalRCT and VoxelJet, enable the fabrication of casting moulds in the incremental process. The application of the RP methods in cast production makes it possible to speed up the prototype preparation process. This is particularly vital to elements of complex shapes. The time required for the manufacture of the model, the mould and the cast proper may vary from a few to several dozen hours

Application of ¹⁴C analyses to source apportionment of carbonaceous PM_2.5 in the UK

Determination of the radiocarbon (<sup>14</sup>C) content of airborne particulate matter yields insight into the proportion of the carbonaceous material derived from fossil and contemporary carbon sources. Daily samples of PM<sub>2.5</sub> were collected by high-volume sampler at an urban background site in Birmingham, UK, and the fraction of <sup>14</sup>C in both the total carbon, and in the organic and elemental carbon fractions, determined by two-stage combustion to CO<sub>2</sub>, graphitisation and quantification by accelerator mass spectrometry. OC and EC content was also determined by Sunset Analyzer. The mean fraction contemporary TC in the PM<sub>2.5</sub> samples was 0.50 (range 0.27–0.66, n = 26). There was no seasonality to the data, but there was a positive trend between fraction contemporary TC and magnitude of SOC/TC ratio and for the high values of these two parameters to be associated with air-mass back trajectories arriving in Birmingham from over land. Using a five-compartment mass balance model on fraction contemporary carbon in OC and EC, the following average source apportionment for the TC in these PM<sub>2.5</sub> samples was derived: 27% fossil EC; 20% fossil OC; 2% biomass EC; 10% biomass OC; and 41% biogenic OC. The latter category will comprise, in addition to BVOC-derived SOC, other non-combustion contemporary carbon sources such as biological particles, vegetative detritus, humic material and tyre wear. The proportion of total PM<sub>2.5</sub> at this location estimated to derive from BVOC-derived secondary organic aerosol was 9–29%. The findings from this work are consistent with those from elsewhere in Europe and support the conclusion of a significant and ubiquitous contribution from non-fossil biogenic sources to the carbon in terrestrial aerosol