Guidance and flight control law development for hypersonic vehicles

During the third reporting period our efforts were focused on a reformulation of the optimal control problem involving active state-variable inequality constraints. In the reformulated problem the optimization is carried out not with respect to all controllers, but only with respect to asymptotic controllers leading to the state constraint boundary. Intimately connected with the traditional formulation is the fact that when the reduced solution for such problems lies on a state constraint boundary, the corresponding boundary layer transitions are of finite time in the stretched time scale. Thus, it has been impossible so far to apply the classical asymptotic boundary layer theory to such problems. Moreover, the traditional formulation leads to optimal controllers that are one-sided, that is, they break down when a disturbance throws the system on the prohibited side of the state constraint boundary

Le témoignage du Vaticanus gr. 163 pour la période entre 945-963

  A. Μαρκόπουλος Ἡ συμβολὴ  τοῦ  χειρογράφου Vaticanus gr. 163 γιὰ τὴ χρονικὴ περίοδο 945-963 Τὸ χειρόγραφο Vaticanus gr. 163 παραδίδει, ἀνάμεσα σὲ ἄλλα ἱστορικά κείμενα, καὶ μία μορφὴ τῆς χρονογραφίας τοῦ Συμεὼν Λογοθέτη. Ἡ ἰδιαιτερότητα τῆς μορφῆς αὐτῆς εἶναι ὅτι ἡ διήγηση δὲ διακόπτεται μὲ τὸ θάνατο τοῦ Ρωμανοῦ Λακαπηνοῦ, ὅπως συνήθως συμβαίνει μὲ τὰ χειρόγραφα τοῦ Λογοθέτη, ἀλλὰ συνεχίζεται μέχρι τὴν ἀναγόρευση στὸ θρόνο τοῦ Νικηφόρου Φωκᾶ (963). Ἀποτελεῖ ἔτσι σημαντικὴ ἱστορικὴ πηγή για τα γεγονότα αὐτῆς τῆς περιόδου.  Ἡ μελέτη περιλαμβάνει ἔκδοση τῶν φφ. 58ν-61 τοῦ χειρογράφου Vaticanus gr. 163 ποὺ καλύπτουν τὸ χρονικὸ διάστημα μεταξὺ τῶν ἐτῶν 945-963. Ἡ ἔκδοση συνοδεύεται ἀπὸ ἱστορικὸ σχολιασμό.  A. Μαρκόπουλος Ἡ συμβολὴ  τοῦ  χειρογράφου Vaticanus gr. 163 γιὰ τὴ χρονικὴ περίοδο 945-963 Τὸ χειρόγραφο Vaticanus gr. 163 παραδίδει, ἀνάμεσα σὲ ἄλλα ἱστορικά κείμενα, καὶ μία μορφὴ τῆς χρονογραφίας τοῦ Συμεὼν Λογοθέτη. Ἡ ἰδιαιτερότητα τῆς μορφῆς αὐτῆς εἶναι ὅτι ἡ διήγηση δὲ διακόπτεται μὲ τὸ θάνατο τοῦ Ρωμανοῦ Λακαπηνοῦ, ὅπως συνήθως συμβαίνει μὲ τὰ χειρόγραφα τοῦ Λογοθέτη, ἀλλὰ συνεχίζεται μέχρι τὴν ἀναγόρευση στὸ θρόνο τοῦ Νικηφόρου Φωκᾶ (963). Ἀποτελεῖ ἔτσι σημαντικὴ ἱστορικὴ πηγή για τα γεγονότα αὐτῆς τῆς περιόδου.  Ἡ μελέτη περιλαμβάνει ἔκδοση τῶν φφ. 58ν-61 τοῦ χειρογράφου Vaticanus gr. 163 ποὺ καλύπτουν τὸ χρονικὸ διάστημα μεταξὺ τῶν ἐτῶν 945-963. Ἡ ἔκδοση συνοδεύεται ἀπὸ ἱστορικὸ σχολιασμό

Rapid near-optimal aerospace plane trajectory generation and guidance

Effort was directed toward the problems of the real time trajectory optimization and guidance law development for the National Aerospace Plane (NASP) applications. In particular, singular perturbation methods were used to develop guidance algorithms suitable for onboard, real time implementation. The progress made in this research effort is reported

Assessing the effectiveness of usability evaluation methods for children

The comparison of three Usability Evaluation Methods (UEM's) is reported with respect to the number of problems uncovered on software products, by children participants. The UEM's compared require different levels of verbalisation of the child that is performing the evaluation. Age of the children, gender, verbal competence, and extroversion level are things that could influence which UEM works best. The outcome of the experiment was that a UEM that requires the children to verbalise a lot is the most effective, and that girls find more problems in the program than boys

Understanding How Users Engage in an Immersive Virtual Reality-Based Live Event

Virtual Reality combined with social functioning is a lucrative business direction. Due to COVID-19, a need for better social interaction is identified urgently both in education institutes and the business sector. In this paper, we will show two business cases where social functioning is needed. The first one illustrates how the business sector can use Virtual Reality Social Platform (VRSP) in remote events. As a case study, we have selected Spinverse’s Summer Day organized in Microsoft AltspaceVR. The second business case, in turn, classifies requirements for Virtual Reality Social platforms. This has been studied in close cooperation with XR Presence. Results show that current technologies offer many features to be used, but at the same time, there are needs for further development. In addition, more studies are needed in technology acceptance, usability, user experience, and business impact

Democratic Organizational Culture for SMEs Innovation Transformation and Corporate Entrepreneurship

The contribution of the Small and Medium Size Enterprises (SMEs) in every economy is undeniably significant. Still, their existence relies on their leadership’s ability to respond to the continuous challenges utilizing best their limited resources. This paper introduces a Democratic Leadership Change Integration Model (DLCIM) that can be used globally to support and institutionalize SMEs’ innovation by maximizing their human intellectual capital’s effectiveness democratically. Knowledge democratization is a crucial stage in knowledge generation. Its benefits encourage both the employees and the organization to create innovative products and services under ethical management values and principles. The proposed framework helps organizations and SMEs achieve a knowledge-based democratic company-employee relationship. It encapsulates the integration of The Company Democracy Model as the tool and base for innovation, the ADKAR model for change management, and the Self-Determination Theory as a leadership principle

An efficient feti based solver for elasto-plastic problems of mechanics

This paper illustrates how to implement effectively solvers for elasto-plastic problems. We consider the time step problems formulated by nonlinear variational equations in terms of displacements. To treat nonlinearity and nonsmoothnes we use semismooth Newton method. In each Newton iteration we have to solve linear system of algebraic equations and for the numerical solution of the linear systems we use TFETI algorithm. In our benchmark we compute von Misses plasticity with isotropic hardening and use return mapping concept

Avatar Based Multiplayer Functionalities in Next Generation Communication and Learning in Virtual Reality Social Platforms – Case MarISOT Room

Virtual Reality Social Platforms are increasingly in use in conferences, and exhibitions. COVID19 pandemic is the main reason for a rapid growth but there are reasons such as climate change to believe these technologies will be used widely once we will enter to the post pandemic era. In this paper, we will introduce our vision to combine social functioning and hands-on-training features in one package. We have participated in and organized various events using existing virtual reality social platforms. We will analyze in this paper their pros and cons plus introduce our own technology trials. As a result, we have better understanding what development tools and how much resources would be needed to be able to create the first minimal viable product combining social functioning and hands-on-training features