University of Cyprus

About: University of Cyprus is a education organization based out in Nicosia, Cyprus. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 3624 authors who have published 15157 publications receiving 412135 citations.

ACLP: Abductive Constraint Logic Programming

Abstract: This paper presents the framework of Abductive Constraint Logic Programming (ACLP), which integrates Abductive Logic Programming (ALP) and Constraint Logic Programming (CLP). In ACLP, the task of abduction is supported and enhanced by its non-trivial integration with constraint solving. This integration of constraint solving into abductive reasoning facilitates a general form of constructive abduction and enables the application of abduction to computationally demanding problems. The paper studies the formal declarative and operational semantics of the ACLP framework together with its application to various problems. The general characteristics of the computation of ACLP and of its application to problems are also discussed. Empirical results based on an implementation of the ACLP framework on top of the CLP language of ECLiPSe show that ACLP is computationally viable, with performance comparable to the underlying CLP framework on which it is built. In addition, our experiments show the natural ability for ACLP to accommodate easily and in a robust way new or changing requirements of the original problem. ACLP thus combines the advantages of modularity and flexibility of the high-level representation afforded by abduction together with the computational effectiveness of low-level specialised constraint solving.

Is one performing the treatment data of adsorption kinetics correctly

Abstract: In the literature, the linear form of the pseudo-first-order (PFO) and pseudo-second-order (PSO) models are often applied for fitting the data of adsorption kinetics. Many authors have applied the linear form of the PSO model and concluded that such a kinetics is better fitted, based on the values of adsorption capacity at the equilibrium (qe) and the high value (which should be close to 1.0) of the coefficient of determination (R2). The linearized PFO model is usually ruled-out because the values of qe and R2 are worse than those obtained by the linearized PSO. On the other hand, the nonlinear fitting of data is highly recommended for the use of equations that are not typically linear such as kinetics data. In this communication, the data of 52 articles (containing 225 experiments of adsorption kinetics) were collected, and the kinetic data were treated using the linear and nonlinear PFO and PSO models. Results indicated that the values of k2 (the rate constant of the PSO model) calculated from the nonlinear fitting method were quite different from those acquired from the linear one. However, the values of qe2 (adsorption capacity at the equilibrium of the PSO model) are in complete agreement, which induces users to an erroneous decision. Using a linearized kinetic model, all the 225 values of R2 of the PSO model were closer to 1.0 than PFO. However, when nonlinearized fitting of the data was used, 122 out of 225 cases (54.22%) showed that the nonlinear PFO is better fitted than the PSO kinetic model.

Using any surface to realize a new paradigm for wireless communications

Abstract: Programmable wireless environments use unique customizable software processes rather than traditional rigid channel models.

A New Hybrid PLL for Interconnecting Renewable Energy Systems to the Grid

Abstract: There is a need to develop new control strategies for interconnecting renewable energy systems (RESs) to the power grid due to the continuously increasing penetration of RES and, in particular, of wind power systems. The control strategies are typically based on a fast and accurate detection of the phase angle of the grid voltage which may be estimated by using a phase-locked loop (PLL) control circuit. The performance of the PLL under normal and abnormal operational conditions is a crucial aspect, since the RES is desired to operate accurately to support the power system under grid fault conditions. This paper investigates the performance of three different PLLs: a synchronous reference frame (SRF) PLL, a stationary reference frame PLL, and a decoupled double SRF PLL. The results of this investigation motivate the development of a new hybrid PLL which is a combination of the aforementioned PLLs and uses the advantages of each PLL. The proposed decoupled stationary reference frame PLL (dαβPLL) may be an appropriate solution to use in an interconnected RES with fault ride through (FRT) capability, since it prevails the other PLLs with regard to its accuracy under unbalanced faults. Furthermore, it has a lower deviation of the estimated phase after the fault occurs. This could be depicted as a faster response of the dαβPLL within the same frequency limits. The performance of the new hybrid dαβPLL is verified through simulations and experiments. Furthermore, the new PLL is used in an interconnected RES through experiments under normal and FRT operations.