The eigenvalues of isolated bridges with transverse restrains at the end abutments

This paper examines the eigenvalues of multi-span seismically isolated bridges in which the transverse displacement of the deck at the end-abutments is restricted. With this constraint the deck is fully isolated along the longitudinal direction, while along the transverse direction the deck is a simple supported beam at the end abutments which enjoys concentrated restoring forces from the isolation bearings at the center piers. For moderate long bridges the first natural period of the bridge is the first longitudinal period, while the first transverse period is the second period, given that the flexural rigidity of the deck along the transverse direction shortens the isolation period offered by the bearings in that direction. This paper shows that for isolated bridges longer than a certain critical length, the first transverse period becomes longer than the first longitudinal period despite the presence of the flexural rigidity of the deck. This critical length depends on whether the bridge is isolated on elastomeric bearings or on spherical sliding bearings. This result is also predicted with established commercially available numerical codes only when several additional nodes are added along the beam elements which are modeling the deck in-between the bridge piers. On the other hand this result can not be captured with the limiting idealization of a beam on continuous distributed springs (beam on Wrinkler foundation) –a finding that has practical significance in design and system identification studies. Finally, the paper shows that the normalized transverse eigenperiods of any finite-span deck are self-similar solutions that can be represented by a single master curve and are independent of the longitudinal isolation period or on whether the deck is supported on elastomeric or spherical sliding bearings

Role of the Counselor with Computers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89449/1/j.1556-6676.1984.tb02783.x.pd

Cross-platform development frameworks : overview of contemporary technologies and methods for cross-platform application development

This is paper provides an overview of the technologies currently (2016) available and in development which allow the development of cross-platform applications. Both server-side and client-side applications are considered, as well as applications for web, desktop and mobile devices such as smartphones and tablets. A web-based approach is recommended for the development of truly cross-platform applications across devices and operating system. Topics discussed include the contemporary background within which cross-platform technologies are developing, full-stack web development using a MEAN stack, cross-platform mobile development methodologies and web-based desktop application development.peer-reviewe

Mobile language learning : providing tools that allow the asynchronous, casual and sometimes gamified learning of languages on mobile devices

This paper provides an overview of progress being made within the field of mobile language learning. A brief discussion of leading mobile language learning applications ensues, together with a gap analysis providing scope for further research.peer-reviewe

Reasoning About a Service-oriented Programming Paradigm

This paper is about a new way for programming distributed applications: the service-oriented one. It is a concept paper based upon our experience in developing a theory and a language for programming services. Both the theoretical formalization and the language interpreter showed us the evidence that a new programming paradigm exists. In this paper we illustrate the basic features it is characterized by

A Lifetime-based Garbage Collector for LISP Systems on General-Purpose Computers

Garbage collector performance in LISP systems on custom hardware has been substantially improved by the adoption of lifetime-based garbage collection techniques. To date, however, successful lifetime-based garbage collectors have required special-purpose hardware, or at least privileged access to data structures maintained by the virtual memory system. I present here a lifetime-based garbage collector requiring no special-purpose hardware or virtual memory system support, and discuss its performance

Extension of direct displacement-based design methodology for bridges to account for higher mode effects

An improvement is suggested to the direct displacement-based design (DDBD) procedure for bridges to account for higher mode effects, the key idea being not only the proper prediction of a target-displacement profile through the effective mode shape (EMS) method (wherein all significant modes are considered), but also the proper definition of the corresponding peak structural response. The proposed methodology is then applied to an actual concrete bridge wherein the different pier heights and the unrestrained transverse displacement at the abutments result in an increased contribution of the second mode. A comparison between the extended and the 'standard' DDBD is conducted, while further issues such as the proper consideration of the degree of fixity at the pier’s top and the effect of the deck’s torsional stiffness are also investigated. The proposed methodology and resulting designs are evaluated using nonlinear response-history analysis (NLRHA) for a number of spectrum-compatible motions. Unlike the 'standard' DDBD, the extended procedure adequately reproduced the target-displacement profile providing at the same time a good estimate of results regarding additional design quantities such as yield displacements, displacement ductilities etc., closely matching the results of the more rigorous NLRHA. However, the need for additional iterations clearly indicates that practical application of the proposed procedure is feasible only if it is fully 'automated', i.e. implemented in a software package

Metaverse education : opportunities and challenges for immersive learning in virtual environments

This research identifies key terms related to the Metaverse. It investigates the pros and cons of using this immersive technology for educational purposes. The findings suggest that the Metaverse provides multi sensory experiences in three-dimensional (3D) environments and enables individuals to interact with other users and physical objects in virtual worlds. Yet, they also indicate that there are a number of challenges that have to be dealt with, including the cost of the infrastructure; the degree of freedom of its users; regulatory concerns, privacy and security of the personal data; as well as possible addictions and mental health issues if individuals are exposed to prolonged use, among others. This contribution implies that there is scope for educators to continue developing the Metaverse’s virtual spaces as it can create infinite possibilities for the development of the students’ knowledge, competences and abilities. At the same time, educators and students ought to be warned and properly informed about its possible dangers.peer-reviewe