Point-of-Interest Recommender Systems based on Location-Based Social Networks: A Survey from an Experimental Perspective

Point-of-Interest recommendation is an increasing research and developing area within the widely adopted technologies known as Recommender Systems. Among them, those that exploit information coming from Location-Based Social Networks (LBSNs) are very popular nowadays and could work with different information sources, which pose several challenges and research questions to the community as a whole. We present a systematic review focused on the research done in the last 10 years about this topic. We discuss and categorize the algorithms and evaluation methodologies used in these works and point out the opportunities and challenges that remain open in the field. More specifically, we report the leading recommendation techniques and information sources that have been exploited more often (such as the geographical signal and deep learning approaches) while we also alert about the lack of reproducibility in the field that may hinder real performance improvements.

Stability Assessment of Rock Mass System under Multiple Adjacent Structures

Numerical modeling is important for exploring the fundamental processes occurring in rock and for evaluating the real performance of structures built on and in rock mass system, and thus for supporting the design of rock engineering problems. Estimating the stability of rock mass foundation systems entirely based on a theoretical approach is a complicated task if there exists overlapping of their potential collapse modes. This paper applies finite element limit analysis to evaluate the bearing capacity of equally spaced multiple strip footings resting on rock mass obeying the modified non-linear Hoek–Brown failure criterion. Numerical solutions are expressed in terms of the efficiency factor that is dependent on the spacing between footings, as well as the rock mass properties. In addition, the effects of surface surcharge and footing roughness are quantified. The maximum spacing at which the interfering effect of adjacent footings becomes disappeared is evaluated and an algebraic expression for approximating the maximum spacing is proposed. Failure mechanisms for a few cases of rock mass under multiple strip footings are examined.

Is Synthetic The New Real? Performance Analysis of Time Series Generation Techniques with Focus on Network Load Forecasting

This paper explores whether Generative Adversarial Networks (GANs) can produce realistic network load data that can be utilized to train machine learning models in lieu of real data. In this regard, we evaluate the performance of three recent GAN architectures on the Telecom Italia data set across a set of qualitative and quantitative metrics. Our results show that GAN generated synthetic data is indeed similar to real data and forecasting models trained on this data achieve similar performance to those trained on real data.

Is Synthetic The New Real? Performance Analysis of Time Series Generation Techniques with Focus on Network Load Forecasting

This paper explores whether Generative Adversarial Networks (GANs) can produce realistic network load data that can be utilized to train machine learning models in lieu of real data. In this regard, we evaluate the performance of three recent GAN architectures on the Telecom Italia data set across a set of qualitative and quantitative metrics. Our results show that GAN generated synthetic data is indeed similar to real data and forecasting models trained on this data achieve similar performance to those trained on real data.

Residential Solar Thermal Performance Considering Self-Shading Incidence between Tubes in Evacuated Tube and Flat Plate Collectors

The performance of solar thermal technology under high-altitude equatorial climatic and solar path conditions has not been determined. Evacuated tube solar collectors are more efficient than flat plate collectors in cold and cloudy regions; however, due to their dependence on orientation, the irradiation incidence between the tubes of these collectors can be blocked. In this study, the performance of these types of collectors was analyzed to determine the implications of their orientation under these specific climate conditions. Four solar thermal systems were installed: two of the systems used evacuated tube collectors, and two used flat plate collectors. Each collector was connected to storage and discharge points to simulate residential consumption when observing the real performance of the four systems in terms of irradiation availability. The evacuated tube collectors were more efficient and reduced the backup energy requirement by up to 20.6% more on average than the flat plate collectors. In addition, the performance of the evacuated tube collectors increased by up to 9.8% when the tubes were arranged parallel to the solar path, compared to when they were arranged perpendicular to the solar path, verifying that the blockage effect is an important parameter to consider for evacuated tube technology. The main novelty of this research is the comparison of these two technologies under different orientations, with perpendicular and parallel dispositions toward the solar path, in a high-altitude equatorial location where solar collectors are not typically oriented in any particular orientation. To the best of our knowledge, this is the first complete analysis of real systems deployed under these conditions.

Spectral efficiency analysis of two-user Downlink PD-NOMA with LTE modulation and coding schemes

Non-orthogonal multiple access (NOMA) is a promising user multiplexing technique for future wireless networks that allows increasing their spectral efficiency (SE). Power-Domain NOMA (PD-NOMA) is one of the most perspective techniques in the NOMA group. It makes it possible to perform the transmission of information symbols of several users within the same time-frequency resource segment (RS) without a spreading code. Many research works show the high efficiency of PD-NOMA compared to the orthogonal multiple access (OMA). However, these results are obtained analytically using Shannon’s formula and not taking into account the real performance of existing modulation and coding schemes (MCS). The issue is that it is impossible to obtain the achievable practical performance of PD-NOMA systems in this way. We obtain the SE in RS of a PD-NOMA system with Long Term Evolution (LTE) MCS’s and compare it with OMA. As a result, we conclude that PD-NOMA gains the system SE when the multiplexed user’s signal-to-noise ratio (SNR) outreaches the threshold of the highest performing MCS provided for the transmission by a MCS table.

Illusions of Liveness: Producer as Composer

<p>The practise of creating music for the recorded medium has been a fluid and constantly changing enterprise since its inception. Emergences of new studio technologies over the last fifty years have spurred new cultures, philosophies and approaches to music production and composition, ultimately seeing a merging of the once disparate roles of producer and composer. It is this contemporary, technology-informed new role of producer-composer that brings with it discussion - for much of which there is no general consensus - over issues pertaining to perceived liveness, the producer-composer’s control over the resulting sound, and most contentiously the use of music technology itself: its transparency and its legitimacy as substitutions for real instruments. These are all fluid and complex issues and this paper does not attempt to provide answers for, nor take a definitive stance on them other than in the sharing of opinions formed from my own experiences in applying production as composition to the creative aspect of this project. In this paper I seek to share some of the current discussion regarding production-as-composition, in light of my own compositional experiment, which strives to create a simulation of real-performance via almost entirely artificial means within an idealised, hyper-musical sonic environment. By bringing together real musicians and virtual instruments within a recorded track and edited via music production technology, the experiment aimed to produce an illusion of liveness.</p>

Illusions of Liveness: Producer as Composer

<p>The practise of creating music for the recorded medium has been a fluid and constantly changing enterprise since its inception. Emergences of new studio technologies over the last fifty years have spurred new cultures, philosophies and approaches to music production and composition, ultimately seeing a merging of the once disparate roles of producer and composer. It is this contemporary, technology-informed new role of producer-composer that brings with it discussion - for much of which there is no general consensus - over issues pertaining to perceived liveness, the producer-composer’s control over the resulting sound, and most contentiously the use of music technology itself: its transparency and its legitimacy as substitutions for real instruments. These are all fluid and complex issues and this paper does not attempt to provide answers for, nor take a definitive stance on them other than in the sharing of opinions formed from my own experiences in applying production as composition to the creative aspect of this project. In this paper I seek to share some of the current discussion regarding production-as-composition, in light of my own compositional experiment, which strives to create a simulation of real-performance via almost entirely artificial means within an idealised, hyper-musical sonic environment. By bringing together real musicians and virtual instruments within a recorded track and edited via music production technology, the experiment aimed to produce an illusion of liveness.</p>

Analysis of construction sub-processes for the evaluation of the real performance of tower cranes

The productivity of work performed at construction sites is primarily dependent on the effective deployment and use of construction machinery. Nevertheless, manufacturers do not state the actual performance of their machinery because it is difficult to determine due to its dependence on the specific conditions present at each construction site. One of the most important machines used in the construction of buildings is the tower crane, which provides secondary transport of material onsite. In order to evaluate the effectiveness of the use of such machines using a deterministic or stochastic approach, a relatively extensive and exact set of data describing the activities of a given tower crane needs to be prepared. These data describe the real requirements of ongoing construction sub-processes with regard to the utilisation of tower cranes. This contribution concerns the analysis of key construction sub-processes during the building of monolithic reinforced concrete structures in connection with secondary transport at the construction site; in particular, it describes the preparation and processing of this data for the evaluation of real time requirements placed on tower cranes.

Study to Increase the TRL of Exoskeleton ERMIS Based on a Methodology to the Identification of Real Performance Parameters

Many exoskeletons in scientific communications and patents only reach a technology readiness level corresponding to an experimental physical model (EPM) or a low-fidelity prototype. While only operational in a laboratory environment, the increasing technology readiness level (TRL) in exoskeletons is not widely studied. This work presents a study to reach this aim based on a new methodology that includes two phases, eleven steps, and four case studies from EPM (TRL3) of ERMIS up to TRL 5 of ERMIS. The results of this article show the increase in TRL based on the analysis of the operational parameters of the ERMIS exoskeleton. The validation of the passive rehabilitation movements was made by characterizing the points of their trajectories assisted by an anthropomorphic mechanism used to measure the end-effector position of ERMIS by means of the acquisition of data, obtaining an error of 20 mm. In conclusion, the real performance parameters are detailed, explaining their causes according to the behavior of the exoskeleton in a real environment operating the four case studies. It presents the group of parameters that reach the TRL 5, which were validated in Computer-Aided Design (CAD) software.