460 research outputs found
Evolutionary squeaky wheel optimization: a new framework for analysis
Squeaky wheel optimization (SWO) is a relatively new metaheuristic that has been shown to be effective for many real-world problems. At each iteration SWO does a complete construction of a solution starting from the empty assignment. Although the construction uses information from previous iterations, the complete rebuilding does mean that SWO is generally effective at diversification but can suffer from a relatively weak intensification. Evolutionary SWO (ESWO) is a recent extension to SWO that is designed to improve the intensification by keeping the good components of solutions and only using SWO to reconstruct other poorer components of the solution. In such algorithms a standard challenge is to understand how the various parameters affect the search process. In order to support the future study of such issues, we propose a formal framework for the analysis of ESWO. The framework is based on Markov chains, and the main novelty arises because ESWO moves through the space of partial assignments. This makes it significantly different from the analyses used in local search (such as simulated annealing) which only move through complete assignments. Generally, the exact details of ESWO will depend on various heuristics; so we focus our approach on a case of ESWO that we call ESWO-II and that has probabilistic as opposed to heuristic selection and construction operators. For ESWO-II, we study a simple problem instance and explicitly compute the stationary distribution probability over the states of the search space. We find interesting properties of the distribution. In particular, we find that the probabilities of states generally, but not always, increase with their fitness. This nonmonotonocity is quite different from the monotonicity expected in algorithms such as simulated annealing
Cardiovascular Risk in Patients with Psoriatic Arthritis
Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. In addition to skin and joint involvement, there is increasing evidence suggesting that patients with PsA also have an increase in risk of clinical and subclinical cardiovascular diseases, mostly due to accelerating atherosclerosis. Both conventional and nonconventional cardiovascular risk factors contribute to the increased cardiovascular risk in PsA. Chronic inflammation plays a pivotal role in the pathogenesis of atherosclerosis in PsA, acting independently and/or synergistically with the conventional risk factors. In this paper, we discuss the current literature indicating that patients with PsA are at risk of cardiovascular diseases
AaKOS: Aspect-adaptive Knowledge-based Opinion Summarization
The rapid growth of information on the Internet has led to an overwhelming
amount of opinions and comments on various activities, products, and services.
This makes it difficult and time-consuming for users to process all the
available information when making decisions. Text summarization, a Natural
Language Processing (NLP) task, has been widely explored to help users quickly
retrieve relevant information by generating short and salient content from long
or multiple documents. Recent advances in pre-trained language models, such as
ChatGPT, have demonstrated the potential of Large Language Models (LLMs) in
text generation. However, LLMs require massive amounts of data and resources
and are challenging to implement as offline applications. Furthermore, existing
text summarization approaches often lack the ``adaptive" nature required to
capture diverse aspects in opinion summarization, which is particularly
detrimental to users with specific requirements or preferences. In this paper,
we propose an Aspect-adaptive Knowledge-based Opinion Summarization model for
product reviews, which effectively captures the adaptive nature required for
opinion summarization. The model generates aspect-oriented summaries given a
set of reviews for a particular product, efficiently providing users with
useful information on specific aspects they are interested in, ensuring the
generated summaries are more personalized and informative. Extensive
experiments have been conducted using real-world datasets to evaluate the
proposed model. The results demonstrate that our model outperforms
state-of-the-art approaches and is adaptive and efficient in generating
summaries that focus on particular aspects, enabling users to make
well-informed decisions and catering to their diverse interests and
preferences.Comment: 21 pages, 4 figures, 7 table
A Component Based Heuristic Search Method with Evolutionary Eliminations
Nurse rostering is a complex scheduling problem that affects hospital
personnel on a daily basis all over the world. This paper presents a new
component-based approach with evolutionary eliminations, for a nurse scheduling
problem arising at a major UK hospital. The main idea behind this technique is
to decompose a schedule into its components (i.e. the allocated shift pattern
of each nurse), and then to implement two evolutionary elimination strategies
mimicking natural selection and natural mutation process on these components
respectively to iteratively deliver better schedules. The worthiness of all
components in the schedule has to be continuously demonstrated in order for
them to remain there. This demonstration employs an evaluation function which
evaluates how well each component contributes towards the final objective. Two
elimination steps are then applied: the first elimination eliminates a number
of components that are deemed not worthy to stay in the current schedule; the
second elimination may also throw out, with a low level of probability, some
worthy components. The eliminated components are replenished with new ones
using a set of constructive heuristics using local optimality criteria.
Computational results using 52 data instances demonstrate the applicability of
the proposed approach in solving real-world problems.Comment: 27 pages, 4 figure
Immunopathological Roles of Cytokines, Chemokines, Signaling Molecules, and Pattern-Recognition Receptors in Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown etiology affecting more than one million individuals each year. It is characterized by B- and T-cell hyperactivity and by defects in the clearance of apoptotic cells and immune complexes. Understanding the complex process involved and the interaction between various cytokines, chemokines, signaling molecules, and pattern-recognition receptors (PRRs) in the immune pathways will provide valuable information on the development of novel therapeutic targets for treating SLE. In this paper, we review the immunopathological roles of novel cytokines, chemokines, signaling molecules, PRRs, and their interactions in immunoregulatory networks and suggest how their disturbances may implicate pathological conditions in SLE
Video-rate centimeter-range optical coherence tomography based on dual optical frequency combs by electro-optic modulators
Imaging speed and range are two important parameters for optical coherence tomography (OCT). A conventional video-rate centimeter-range OCT requires an optical source with hundreds of kHz repetition rate and needs the support of broadband detectors and electronics (>1 GHz). In this paper, a type of video-rate centimeter-range OCT system is proposed and demonstrated based on dual optical frequency combs by leveraging electro-optic modulators. The repetition rate difference between dual combs, i.e. the A-scan rate of dual-comb OCT, can be adjusted within 0~6 MHz. By down-converting the interference signal from optical domain to radio-frequency domain through dual comb beating, the down-converted bandwidth of the interference signal is less than 22.5 MHz which is at least two orders of magnitude lower than that in conventional OCT systems. A LabVIEW program is developed for video-rate operation, and the centimeter imaging depth is proved by using 10 pieces of 1-mm thick glass stacked as the sample. The effective beating bandwidth between two optical comb sources is 7 nm corresponding to ~108 comb lines, and the axial resolution of the dual-comb OCT is 158 µm. Dual optical frequency combs provide a promising solution to relax the detection bandwidth requirement in fast long-range OCT systems
Predictors of functional deterioration in Chinese patients with Psoriatic arthritis: A longitudinal study.
10.1186/1471-2474-15-284BMC Musculoskeletal Disorders15128
Temporal and Spatial Variability of Precipitation from Observations and Models
Principal component analysis (PCA) is utilized to explore the temporal and spatial variability of precipitation from GPCP and a CAM5 simulation from 1979 to 2010. In the tropical region, the interannual variability of tropical precipitation is characterized by two dominant modes (El Niño and El Niño Modoki). The first and second modes of tropical GPCP precipitation capture 31.9% and 15.6% of the total variance, respectively. The first mode has positive precipitation anomalies over the western Pacific and negative precipitation anomalies over the central and eastern Pacific. The second mode has positive precipitation anomalies over the central Pacific and negative precipitation anomalies over the western and eastern Pacific. Similar variations are seen in the first two modes of tropical precipitation from a CAM5 simulation, although the magnitudes are slightly weaker than in the observations. Over the Northern Hemisphere (NH) high latitudes, the first mode, capturing 8.3% of the total variance of NH GPCP precipitation, is related to the northern annular mode (NAM). During the positive phase of NAM, there are negative precipitation anomalies over the Arctic and positive precipitation anomalies over the midlatitudes. Over the Southern Hemisphere (SH) high latitudes, the first mode, capturing 13.2% of the total variance of SH GPCP precipitation, is related to the southern annular mode (SAM). During the positive phase of the SAM, there are negative precipitation anomalies over the Antarctic and positive precipitation anomalies over the midlatitudes. The CAM5 precipitation simulation demonstrates similar results to those of the observations. However, they do not capture both the high precipitation anomalies over the northern Pacific Ocean or the position of the positive precipitation anomalies in the SH
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