747 research outputs found

    Guidance and flight control law development for hypersonic vehicles

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    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

    Rapid near-optimal aerospace plane trajectory generation and guidance

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    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

    A Fintech Approach Towards Resolving the Young Adult Home Ownership Challenge

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    Housing prices globally remain very expensive for young adults while financial instruments to obtain them become more complicated, demanding, and discouraging, especially in the modern post global financial crisis (2007–2017). The way people acquire homes haven’t change over the last 100 years, maintaining the three classic and dominant alternatives which is either thorough mortgages, cash payments, or combination of these. Young adults have been underserved by financial institutions and their products have not yet met young adults’ conditions. This research has been directed to utilize today’s technology and contribute with innovative financing solutions that can addresses the young adults’ needs. The proposed Fintech approach presents the architecture of a technology-based platform whereby Co-sharing agreements between real estate developers and young adults can be created. Such agreements can be integrated into the financial institutions processes to efficiently address and serve this significant target group by delivering creative innovative financing alternatives

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

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    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

    Analytical investigations in aircraft and spacecraft trajectory optimization and optimal guidance

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    A collection of analytical studies is presented related to unconstrained and constrained aircraft (a/c) energy-state modeling and to spacecraft (s/c) motion under continuous thrust. With regard to a/c unconstrained energy-state modeling, the physical origin of the singular perturbation parameter that accounts for the observed 2-time-scale behavior of a/c during energy climbs is identified and explained. With regard to the constrained energy-state modeling, optimal control problems are studied involving active state-variable inequality constraints. Departing from the practical deficiencies of the control programs for such problems that result from the traditional formulations, a complete reformulation is proposed for these problems which, in contrast to the old formulation, will presumably lead to practically useful controllers that can track an inequality constraint boundary asymptotically, and even in the presence of 2-sided perturbations about it. Finally, with regard to s/c motion under continuous thrust, a thrust program is proposed for which the equations of 2-dimensional motion of a space vehicle in orbit, viewed as a point mass, afford an exact analytic solution. The thrust program arises under the assumption of tangential thrust from the costate system corresponding to minimum-fuel, power-limited, coplanar transfers between two arbitrary conics. The thrust program can be used not only with power-limited propulsion systems, but also with any propulsion system capable of generating continuous thrust of controllable magnitude, and, for propulsion types and classes of transfers for which it is sufficiently optimal the results of this report suggest a method of maneuvering during planetocentric or heliocentric orbital operations, requiring a minimum amount of computation; thus uniquely suitable for real-time feedback guidance implementations

    Safety Culture and Collective Commitment in Organizational Context

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    In nuclear power plants and process industry safety is the number one priority over profitability and productivity. In such high-risk environments where individuals work independently their decisions can lead to dangerous situations to coworkers, organizations or even to society. In many cases, a loose commitment to occupational role causes individual to perceive safety culture as something too much detailed which makes them to lose focus on what is important regarding the safety culture. In our view, this is a problem for collective safety culture to raise to a higher level. To understand organizations collective safety culture and safety consciousness it is important to analyze employees individually to see what are their internal feelings, understanding and aims. This paper presents a joint analysis of organization’s safety culture and commitment towards their organization by utilizing also Company Democracy Model (CDM)

    Tetramic and Tetronic Acids as Scaffolds in Bioinorganic and Bioorganic Chemistry

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    Tetramic and tetronic acids are naturally occurring molecules with a variety of biological activities. In this review article, we present the general strategies for the synthesis of these compounds and we reveal the functionalized groups that are responsible for their properties. We also set out their coordinating modes with up-to-date bibliographical references

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

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    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

    Measuring Student Engagement and Commitment on Private Academic Institutions Using Fuzzy Logic Expert System Metrics Applications

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    Even though academic knowledge is provided to academic institutions under very specific academic standards in teaching and research, the instruction’s management can impact significantly the student engagement and commitment on receiving and utilizing such knowledge. To analyse this challenge, a Fuzzy Logic, expert system-based software application has been developed and applied on a private academic institution. In this research the institution participated with 40 undergraduate students, from 24 different countries from two different semesters on the same course. The technology measures the student engagement and commitment via the co-evolute methodology for knowledge elicitation. By utilizing this approach, the management of academic institutions can make development analysis based on concrete bottom-up results. The collective analysis of the test results clearly identifies where students see the needs for greatest development and how they view their current state of engagement

    Phronetic leadership style evaluation with a fuzzy logic application

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    The purpose of leadership style assessments is to determine the basic features and characteristics of leadership behaviours and to reveal the leader’s personality traits and abilities and to increase their self-awareness. The style can be, for example, democratic, autocratic, bureaucratic, laissez-faire, strategic, visionary, transformational, or transactional. However, ordinary assessments do not help leaders analyze their knowledge and wisdom behind their behaviours. The Wisdom Cube seeks to explain wisdom through the four dimensions of wisdom and provides a practical way of understanding the knowledge and wisdom in leadership. By utilising the dimensions and planes of the Wisdom Cube, we can find the way from data handling, information processing, and knowledge creation to wisdom generation. The aim of this research is, therefore, to reveal the ontology of the phronetic leader and to create a practical evaluation tool for leaders. The content of the article covers the elements of the Wisdom Cube, presents related efforts to measure and analyze phronetic leadership characteristics, and shows the practical results of the first test runs with the fuzzy logic-based application. The personal deep understanding of the leadership traits may then help the leaders to turn their current leadership styles more phronetic
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