True-Time Delay-Based Hybrid Precoding Under Time Delay Constraints in Wideband THz Massive MIMO Systems

The beam squint effect that arises in the wideband Terahertz (THz) massive multiple-input multiple-output (MIMO) communication produces a serious array gain loss. True-time delay (TTD)-based hybrid precoding has been considered to compensate for the beam squint effect. By fixing the phase shifter (PS) precoder, a common strategy has been designing TTD precoder under the assumption of unbounded time delay values. In this paper, we present a new approach to the problem of beam squint compensation, based on the joint optimization of the TTD and PS precoders under per TTD device time delay constraints. We first derive a lower bound of the achievable rate and show that in the large system limit the ideal analog precoder that completely compensates for the beam squint is equivalent to the one that maximizes the achievable rate lower bound. Unlike the prior approaches, our approach does not require the unbounded time delay assumption; the range of time delay values that a TTD can produce is strictly limited in our approach. Instead of focusing on the design of TTD values only, we jointly optimize both the TTD and PS values to effectively cope with the practical time delay constraints. Taking the advantage of the proposed joint TTD and PS precoder optimization approach, we quantify the minimum number of TTDs required to produce a predefined array gain performance. The simulation results illustrate the substantially improved performance with the array gain performance guarantee of the proposed joint optimization method

Joint Delay and Phase Precoding Under True-Time Delay Constraints for THz Massive MIMO

A new approach is presented to the problem of compensating the beam squint effect arising in wideband terahertz (THz) hybrid massive multiple-input multiple-output (MIMO) systems, based on the joint optimization of the phase shifter (PS) and true-time delay (TTD) values under per-TTD device time delay constraints. Unlike the prior approaches, the new approach does not require the unbounded time delay assumption; the range of time delay values that a TTD device can produce is strictly limited in our approach. Instead of focusing on the design of TTD values, we jointly optimize both the TTD and PS values to effectively cope with the practical time delay constraints. Simulation results that illustrate the performance benefits of the new method for the beam squint compensation are presented. Through simulations and analysis, we show that our approach is a generalization of the prior TTD-based precoding approaches

The Pulse Of Impulse Buying: An experimental study on the effects of background music tempo on impulse buying

Considering the importance of e-commerce, very little research has examined how marketing stimuli like music affect impulse buying behavior online. In general, the effect of music on impulse buying is not entirely understood yet. Prior research leads us to suggest that music may influence consumers’ ability to exert self-control and thus their receptiveness to product offers in a shopping situation. Most research has been done in offline settings via surveys or field studies, which often makes it difficult to measure traits, attitudes and cognitive resource and to control confounding factors. Our study aims to contribute to research on impulse buying in three ways: 1) observing impulse buying in an e-commerce setting, 2) exploring the relationship between self-control, background music and impulse buying, and 3) proposing an experimental design to study impulse buying in the lab

Democratic Dialogue as a Process to Inform Public Policy

An exploration of the collaborative reconceptualization of a provincial Supervisory Officer’s Qualification Program (SOQP) through the use of dialogic approaches is the focus of this inquiry. The stories, perspectives, and lived experiences of supervisory officers, principals, teachers, parents, students, and members of the public in Ontario were included as essential voices and information sources within policy development conversations. These narratives of experience revealed the forms of knowledge, skills, dispositions, and ethical commitments necessary for effective supervisory officers today and in the future. They also illustrated the transformative nature of narrative dialogue to enlighten, deepen understanding, and alter perspectives. The policy development processes used in this publicly shared educational initiative serve as a model of democratic dialogue. The inclusive and dialogic methods employed to collectively reconceptualize a supervisory officer formation program illustrate an innovative framework for developing policies governing the public good

See It, Say It: Encouraging Citizen Reporting of Sustainability and Inclusivity Infrastructure Issues in Cities

Citizen reporting apps are becoming increasingly popular in smart cities to help local authorities identify, prioritize and resolve issues with public infrastructure faster and according to citizen needs. However, soliciting and sustaining high-quality incident reports is challenging since free riding is an attractive option. Another challenge is making such apps equally open and accessible to less affluent and vulnerable groups. We model citizen reporting as a public good game to investigate how two potential non-monetary, non-competitive interventions affect contributions: increasing the salience of the citizen’s group identity, and increasing the salience of the expressive values. We conducted an online experiment to test our hypotheses. Our results reveal that neither salience of group identity nor expressive values increased contributions toward the public good