4,944 research outputs found
Taming a non-convex landscape with dynamical long-range order: memcomputing Ising benchmarks
Recent work on quantum annealing has emphasized the role of collective
behavior in solving optimization problems. By enabling transitions of clusters
of variables, such solvers are able to navigate their state space and locate
solutions more efficiently despite having only local connections between
elements. However, collective behavior is not exclusive to quantum annealers,
and classical solvers that display collective dynamics should also possess an
advantage in navigating a non-convex landscape. Here, we give evidence that a
benchmark derived from quantum annealing studies is solvable in polynomial time
using digital memcomputing machines, which utilize a collection of dynamical
components with memory to represent the structure of the underlying
optimization problem. To illustrate the role of memory and clarify the
structure of these solvers we propose a simple model of these machines that
demonstrates the emergence of long-range order. This model, when applied to
finding the ground state of the Ising frustrated-loop benchmarks, undergoes a
transient phase of avalanches which can span the entire lattice and
demonstrates a connection between long-range behavior and their probability of
success. These results establish the advantages of computational approaches
based on collective dynamics of continuous dynamical systems
The Impact of Exogenous Shocks on Business Models and Business Relationships: An Empirical Analysis of the Italian Music Industry
Purpose: Scholars have been increasingly interested in understanding business models. However, little attention has been paid to how business models change in reaction to exogenous circumstances and how business relationships alter be-cause of business model changes. This paper investigates how the business model paradigm of the Italian music industry altered in response to two major exogenous influences that impacted the sector: the digital revolution and the COVID-19 pandemic. Design/methodology/approach: As the purpose of this study is to investigate phenomena in a real-world setting, qualitative research methodology has been selected as the most appropriate one. It was decided to conduct sixteen semi-structured interviews with professionals active in the Italian music business, selected through a combination of snowball and convenience sampling. Findings: The empirical findings indicate that the digital revolution and COVID-19 pushed Italian music companies to revise their business models by either reducing or adding the number of linkages to the existing ones. This was done in order for the companies to remain competitive in an environment that is constantly changing and to outcompete rivals. Originality/value: Few studies have evaluated how business relationships alter in response to the many business models emerging in the music industry due to external causes. This research is one of the first to examine music companies’ reactions to exogenous events such as crises or disruptive advances that affect the competitive landscap
CT-based tumour response criteria compared after combined treatment for liver metastases of colorectal cancer
open6noPurpose: The aim of this analysis is to compare different tumour response
criteria (TRC) after chemotherapy combined with bevacizumab in liver
metastases from colorectal cancer (mCRC) to ascertain the best early
prognostic indicator of response.
Methods and Materials: 103 target liver metastases from 65 mCRC patients
treated with chemoterapy plus bevacizumab were examined at the Istituto
Oncologico Veneto IOV-IRCSS (March 2008-January 2013). All patients had
baseline CT and at least one follow-up scan. Tumour response was
retrospectively analyzed by two radiologists using RECIST1.1, modified Choi,
and Chun morphologic criteria. Tumour response, classified as good (complete
or partial response) or poor (stable or progressive disease), was compared
with progression-free survival (PFS) at first follow-up (t1) and time of best
response. Interobserver agreement and concordance between TRC were
measured.
Results: At t1, 32.31% showed a good response according to RECIST1.1
(median PFS 11.1), 84.62% according to Choi (median PFS 10.8). These
percentages rose to 49.23% (median PFS 12.1) and 87.69% (median PFS
10.8), respectively, at the time of best response. According to Chun, 67.69%
showed a good response at the time of best response (median PFS 10.8). The
Choi criteria detected a higher proportion of good responders at t1, showing a
better correlation with PFS; all methods correlated with PFS at the time of best
response.
Conclusion: The Choi criteria proved more consistent in the early detection of
response in mCRC treated with chemotherapy plus bevacizumab,
underscoring the importance of using these criteria in the early assessment of
response to combined treatment.openopenVarotto, A.; Di Grazia, L.; Aliberti, C.; Bergamo, F.; Nardin, M.; Pomerri, F.Varotto, A.; Di Grazia, L.; Aliberti, C.; Bergamo, F.; Nardin, M.; Pomerri, Fabi
Editorial: From Meaning of Working to Meaningful Lives: The Challenges of Expanding Decent Work
This Research Topic explores issues that are central to the continued relevance of organizational and vocational psychology, and equally central to the well-being of individuals and communities. The cohering theme of this publication revolves around the question of how people can establish meaningful lives and meaningful work experiences in light of the many challenges that are reducing access to decent work. Another essential contextual factor that is explored in this volume is the Decent Work Agenda (International Labour Organization, 2008), which represents an initiative by the International Labour Organization. In this book, we hope to enrich the Decent Work Agenda by infusing the knowledge and perspectives of psychology into contemporary discourses about work, and well-being. Another inspiration for this project emerged from the UNESCO Chair in Lifelong guidance and counseling, recently established in Poland in 2013 under the leadership of Jean Guichard, which has focused on advancing research and policy advocacy about decent work. This new era calls for an innovative perspective in constructing decent work and decent lives: the passage from the paradigm of motivation to the paradigm of meaning, where the sustainability of the decent life project is anchored to a meaningful construction. During this period when work is changing so rapidly, leaving people yearning for a sense of connection and meaning, it’s fundamental to create a framework for an explicitly psychological analysis of decent work
MemComputing Integer Linear Programming
Integer linear programming (ILP) encompasses a very important class of
optimization problems that are of great interest to both academia and industry.
Several algorithms are available that attempt to explore the solution space of
this class efficiently, while requiring a reasonable compute time. However,
although these algorithms have reached various degrees of success over the
years, they still face considerable challenges when confronted with
particularly hard problem instances, such as those of the MIPLIB 2010 library.
In this work we propose a radically different non-algorithmic approach to ILP
based on a novel physics-inspired computing paradigm: Memcomputing. This
paradigm is based on digital (hence scalable) machines represented by
appropriate electrical circuits with memory. These machines can be either built
in hardware or, as we do here, their equations of motion can be efficiently
simulated on our traditional computers. We first describe a new circuit
architecture of memcomputing machines specifically designed to solve for the
linear inequalities representing a general ILP problem. We call these
self-organizing algebraic circuits, since they self-organize dynamically to
satisfy the correct (algebraic) linear inequalities. We then show simulations
of these machines using MATLAB running on a single core of a Xeon processor for
several ILP benchmark problems taken from the MIPLIB 2010 library, and compare
our results against a renowned commercial solver. We show that our approach is
very efficient when dealing with these hard problems. In particular, we find
within minutes feasible solutions for one of these hard problems (f2000 from
MIPLIB 2010) whose feasibility, to the best of our knowledge, has remained
unknown for the past eight years
- …