scholarly journals Sequential Recommender Systems: Challenges, Progress and Prospects

2019 ◽  
Author(s):  
Shoujin Wang ◽  
Liang Hu ◽  
Yan Wang ◽  
Longbing Cao ◽  
Quan Z. Sheng ◽  
...  
Keyword(s):  
Recommender Systems ◽  
Research Area ◽  
Research Progress ◽  
Important Research ◽  
Research Directions ◽  
User Behaviors ◽  
Precise Characterization ◽  
Content Based Filtering ◽  
Over Time

The emerging topic of sequential recommender systems (SRSs) has attracted increasing attention in recent years. Different from the conventional recommender systems (RSs) including collaborative filtering and content-based filtering, SRSs try to understand and model the sequential user behaviors, the interactions between users and items, and the evolution of users’ preferences and item popularity over time. SRSs involve the above aspects for more precise characterization of user contexts, intent and goals, and item consumption trend, leading to more accurate, customized and dynamic recommendations. In this paper, we provide a systematic review on SRSs. We first present the characteristics of SRSs, and then summarize and categorize the key challenges in this research area, followed by the corresponding research progress consisting of the most recent and representative developments on this topic. Finally, we discuss the important research directions in this vibrant area.

scholarly journals Graph Learning based Recommender Systems: A Review

2021 ◽  
Author(s):  
Shoujin Wang ◽  
Liang Hu ◽  
Yan Wang ◽  
Xiangnan He ◽  
Quan Z. Sheng ◽  
...  
Keyword(s):  
Systematic Review ◽  
Recommender Systems ◽  
Rapid Development ◽  
Research Area ◽  
Learning Approaches ◽  
Graph Learning ◽  
Promising Direction ◽  
Learning Techniques ◽  
Fast Development ◽  
Content Based Filtering

Recent years have witnessed the fast development of the emerging topic of Graph Learning based Recommender Systems (GLRS). GLRS mainly employ advanced graph learning approaches to model users’ preferences and intentions as well as items’ characteristics and popularity for Recommender Systems (RS). Differently from other approaches, including content based filtering and collaborative filtering, GLRS are built on graphs where the important objects, e.g., users, items, and attributes, are either explicitly or implicitly connected. With the rapid development of graph learning techniques, exploring and exploiting homogeneous or heterogeneous relations in graphs is a promising direction for building more effective RS. In this paper, we provide a systematic review of GLRS, by discussing how they extract knowledge from graphs to improve the accuracy, reliability and explainability of the recommendations. First, we characterize and formalize GLRS, and then summarize and categorize the key challenges and main progress in this novel research area.

A Physical Route to High Performance Heterojunction Composites: Experiments, Mechanism and Applications

MRS Advances ◽  
2016 ◽  
Vol 1 (6) ◽  
pp. 441-446
Author(s):  
Delong Li ◽  
Chengzhi Luo ◽  
Chunxu Pan
Keyword(s):  
High Temperature ◽  
Thermal Diffusion ◽  
High Performance ◽  
Diffusion Mechanism ◽  
Research Area ◽  
Research Progress ◽  
Photocatalytic Efficiency ◽  
Important Research ◽  
Oxide Semiconductors ◽  
Important Research Area

ABSTRACTIn order to enhance the photocatalytic efficiency of oxide semiconductors, variant processes have been proposed. The creation of the heterojunction composites has attracted considerable attentions and developed into an important research area for the high performance photocatalyst preparation. In this paper, we introduce the research progress on heterojunction composites which were prepared via a novel physical route with relatively high temperature treatments. It is hope that this mini-review can inspire research interest in the realm of heterojunction synthesis based on the thermal diffusion mechanism.

scholarly journals Network Brokerage: An Integrative Review and Future Research Agenda

2020 ◽  
Vol 46 (6) ◽  
pp. 1092-1120 ◽  
Author(s):  
Seok-Woo Kwon ◽  
Emanuela Rondi ◽  
Daniel Z. Levin ◽  
Alfredo De Massis ◽  
Daniel J. Brass
Keyword(s):  
Research Agenda ◽  
Research Area ◽  
Future Research ◽  
Important Research ◽  
Research Gaps ◽  
Comprehensive Review ◽  
Research Areas ◽  
Future Research Agenda ◽  
And Behavior ◽  
Over Time

Network brokerage research has grown rapidly in recent decades, spanning the boundaries of multiple social science disciplines as well as diverse research areas within management. Accordingly, we take stock of the literature on network brokerage and provide guidance on ways to move this burgeoning research area forward. We provide a comprehensive review of this literature, including crucial dimensions of the concept itself in terms of brokerage structure and behavior, a set of key categories of factors surrounding the brokerage concept (antecedents, outcomes, and moderators), and an overview of brokerage dynamics over time. We use these dimensions and categories to depict network brokerage’s theoretical and empirical underpinnings as well as evaluate prior research efforts. In so doing, we offer a means to summarize and synthesize this large, interdisciplinary literature, identify important research gaps, and offer promising directions for future research.

scholarly journals An Evaluation Framework of Trust Aware Recommender System

2018 ◽  
Vol 7 (4.33) ◽  
pp. 5
Author(s):  
S. Masrom ◽  
N. Khairuddin ◽  
A. Abdul Rahman ◽  
A. Azizan ◽  
A. S.A. Rahman
Keyword(s):  
Collaborative Filtering ◽  
Recommender Systems ◽  
Recommender System ◽  
Cold Start ◽  
Evaluation Framework ◽  
Research Progress ◽  
Comparison Study ◽  
Common Group ◽  
Common Problems ◽  
Content Based Filtering

To date, there exists a variety of prediction approaches have been used in recommender systems. Among the widely known approaches are Content Based Filtering (CBF) and Collaborative Filtering (CF). Based on literatures, CF with users rating element has been widely used but the approach faced two common problems namely cold start and sparsity. As an alternative, Trust Aware Recommender Systems (TARS) for the CF based users rating has been introduced.  The research progress on TARS improvement is found to be rapidly progressing but lacking in the algorithm evaluation has been started to appear. Many researchers that introduced their new TARS approach provides different evaluation of users’ views for the TARS performances. As a result, the performances of different TARS from different publications are not comparable and difficult to be analyzed. Therefore, this paper is written with objective to provide common group of the users’ views based on trusted users in TARS. Then, this paper demonstrates a comparison study between different TARS techniques with the identified common groups by means of the accuracy error, rating and users coverage. The results therefore provide a relative comparison between different TARS. 

Freedom of Research Area

2018 ◽  
Author(s):  
Brian Weatherson
Keyword(s):  
Academic Freedom ◽  
Research Area ◽  
Academic Departments ◽  
Research Focus ◽  
Disciplinary Boundaries ◽  
Freedom Of Research ◽  
Continued Employment ◽  
Over Time

Some writers have said that academic freedom should extend to giving academics complete freedom over what they choose to research. I argue against this: it is consistent with academic freedom for universities to hire people to research particular subjects, and to make continued employment conditional on at least some of the academic’s research being in the areas they were hired to work in. In practice, many academics think that their fellow academics should be free to choose to work on anything that’s within the disciplinary boundaries of the department they were hired into. I argue that’s both too narrow and too broad. Academic freedom implies that researchers should be allowed to have their research focus drift over time. But the boundaries of permissible drift do not correspond to anything like the boundaries of contemporary academic departments.

scholarly journals Clinical characterization of dysautonomia in long COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicolas Barizien ◽  
Morgan Le Guen ◽  
Stéphanie Russel ◽  
Pauline Touche ◽  
Florent Huang ◽  
...  
Keyword(s):  
Mixed Models ◽  
Repeated Measures ◽  
Physical Medicine ◽  
Persistent Symptoms ◽  
Index Changes ◽  
Changes Over Time ◽  
And Control ◽  
Testing Group ◽  
Over Time

AbstractIncreasing numbers of COVID-19 patients, continue to experience symptoms months after recovering from mild cases of COVID-19. Amongst these symptoms, several are related to neurological manifestations, including fatigue, anosmia, hypogeusia, headaches and hypoxia. However, the involvement of the autonomic nervous system, expressed by a dysautonomia, which can aggregate all these neurological symptoms has not been prominently reported. Here, we hypothesize that dysautonomia, could occur in secondary COVID-19 infection, also referred to as “long COVID” infection. 39 participants were included from December 2020 to January 2021 for assessment by the Department of physical medicine to enhance their physical capabilities: 12 participants with COVID-19 diagnosis and fatigue, 15 participants with COVID-19 diagnosis without fatigue and 12 control participants without COVID-19 diagnosis and without fatigue. Heart rate variability (HRV) during a change in position is commonly measured to diagnose autonomic dysregulation. In this cohort, to reflect HRV, parasympathetic/sympathetic balance was estimated using the NOL index, a multiparameter artificial intelligence-driven index calculated from extracted physiological signals by the PMD-200 pain monitoring system. Repeated-measures mixed-models testing group effect were performed to analyze NOL index changes over time between groups. A significant NOL index dissociation over time between long COVID-19 participants with fatigue and control participants was observed (p = 0.046). A trend towards significant NOL index dissociation over time was observed between long COVID-19 participants without fatigue and control participants (p = 0.109). No difference over time was observed between the two groups of long COVID-19 participants (p = 0.904). Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, that is reflected by the NOL index measurements, compared to control participants. Dysautonomia may explain the persistent symptoms observed in long COVID-19 patients, such as fatigue and hypoxia. Trial registration: The study was approved by the Foch IRB: IRB00012437 (Approval Number: 20-12-02) on December 16, 2020.

scholarly journals Recent Developments of Antimony-Based Anodes for Sodium- and Potassium-Ion Batteries

2021 ◽  
Author(s):  
Bochao Chen ◽  
Ming Liang ◽  
Qingzhao Wu ◽  
Shan Zhu ◽  
Naiqin Zhao ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Low Cost ◽  
Potassium Ion ◽  
Research Progress ◽  
Research Directions ◽  
Weak Charge ◽  
Recent Developments ◽  
High Theoretical Capacity ◽  
Further Development ◽  
Sodium And Potassium

AbstractThe development of sodium-ion (SIBs) and potassium-ion batteries (PIBs) has increased rapidly because of the abundant resources and cost-effectiveness of Na and K. Antimony (Sb) plays an important role in SIBs and PIBs because of its high theoretical capacity, proper working voltage, and low cost. However, Sb-based anodes have the drawbacks of large volume changes and weak charge transfer during the charge and discharge processes, thus leading to poor cycling and rapid capacity decay. To address such drawbacks, many strategies and a variety of Sb-based materials have been developed in recent years. This review systematically introduces the recent research progress of a variety of Sb-based anodes for SIBs and PIBs from the perspective of composition selection, preparation technologies, structural characteristics, and energy storage behaviors. Moreover, corresponding examples are presented to illustrate the advantages or disadvantages of these anodes. Finally, we summarize the challenges of the development of Sb-based materials for Na/K-ion batteries and propose potential research directions for their further development.

Highly precise characterization of the hydration state upon thermal denaturation of human serum albumin using a 65 GHz dielectric sensor

2020 ◽  
Vol 22 (35) ◽  
pp. 19468-19479 ◽  
Author(s):  
Keiichiro Shiraga ◽  
Mako Urabe ◽  
Takeshi Matsui ◽  
Shojiro Kikuchi ◽  
Yuichi Ogawa
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Thermal Denaturation ◽  
Hydration Water ◽  
Biological Functions ◽  
Dielectric Sensor ◽  
Hydration State ◽  
Precise Characterization

The biological functions of proteins depend on harmonization with hydration water surrounding them.

Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction

2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Rietveld Refinements ◽  
Space Group ◽  
X Ray ◽  
Precise Characterization

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

scholarly journals Fabrication of Superconducting Nanowires Using the Template Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1970
Author(s):  
Michael Rudolf Koblischka ◽  
Anjela Koblischka-Veneva
Keyword(s):  
High Temperature ◽  
High Temperature Superconductors ◽  
Sol Gel ◽  
Template Method ◽  
Aao Template ◽  
Superconducting Nanowires ◽  
Research Directions ◽  
Templating Method ◽  
Fabrication And Characterization

The fabrication and characterization of superconducting nanowires fabricated by the anodic aluminium oxide (AAO) template technique has been reviewed. This templating method was applied to conventional metallic superconductors, as well as to several high-temperature superconductors (HTSc). For filling the templates with superconducting material, several different techniques have been applied in the literature, including electrodeposition, sol-gel techniques, sputtering, and melting. Here, we discuss the various superconducting materials employed and the results obtained. The arising problems in the fabrication process and the difficulties concerning the separation of the nanowires from the templates are pointed out in detail. Furthermore, we compare HTSc nanowires prepared by AAO templating and electrospinning with each other, and give an outlook to further research directions.

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