Search results for " Cluster"

Ca impurity in small mixed He-4-He-3 clusters

2009

The structure of small mixed helium clusters doped with one calcium atom has been determined within the diffusion Monte Carlo framework. The results show that the calcium atom sits at the He-4-He-3 interface. This is in agreement with previous studies, both experimental and theoretical, performed for large clusters. A comparison between the results obtained for the largest cluster we have considered for each isotope shows a clear tendency of the Ca atom to reside in a deep dimple at the surface of the cluster for He-4 clusters, and to become fully solvated for He-3 clusters. We have calculated the absorption spectrum of Ca around the 4s4p <- 4s(2) transition and have found that it is bluesh…

Efficient distributed average consensus in wireless sensor networks

2020

International audience; Computing the distributed average consensus in Wireless Sensor Networks (WSNs) is investigated in this article. This problem, which is both natural and important, plays a significant role in various application fields such as mobile agents and fleet vehicle coordination, network synchronization, distributed voting and decision, load balancing of divisible loads in distributed computing network systems, and so on. By and large, the average consensus' objective is to have all nodes in the network converged to the average value of the initial nodes' measurements based only on local nodes' information states. In this paper, we introduce a fully distributed algorithm to a…

Emotions and visitors’ satisfaction at a museum

2014

Purpose – This research aims to investigate whether emotions can be considered as a suitable variable to segment visitors at a museum. Furthermore, it seeks to analyse whether emotions influence visitor satisfaction and whether this depends on objective variables (such as age, gender and level of education) or not. Design/methodology/approach – A structured questionnaire was developed and data were collected at the National Museum of Archaeology “G.A. Sanna” in Sardinia (Italy) via 410 face-to-face interviews. Hierarchical and non-hierarchical cluster analyses and a series of chi-squared tests were run for the purpose of the study. Findings – Two segments were identified. The cluster with …

A Comparative Study on Fuzzy-Clustering-Based Lip Region Segmentation Methods

2011

As the first step of many lip-reading or visual speaker authentication systems, lip region segmentation is of vital importance. And fuzzy clustering based methods have been widely used in lip segmentation. In this paper, four fuzzy clustering based lip segmentation methods have been elaborated with their underlying rationale. Experiments have been carried out evaluate their performance comparatively. From the experimental results, SFCM has the best efficiency and FCMST has the best segmentation accuracy.

Sequential Lip Region Segmentation Using Fuzzy Clustering with Spatial and Temporal Information

2012

For many visual speech recognition and visual speaker authentication systems, lip region extraction is of vital important. In order to segment the lip region accurately and robustly from a lip sequence, a new fuzzy-clustering based algorithm is proposed. In the proposed method, a new dissimilarity measure is introduced to take all the color, spatial and temporal information into consideration. An iterative optimization method is employed to derive the optimal lip region membership map and the final segmentation result. From the experimental results, it is observed that the proposed algorithm can provide superior results compared with other traditional methods.

The structure and biosynthesis of heinamides A1-A3 and B1-B5, antifungal members of the laxaphycin lipopeptide family.

2021

Laxaphycins are a family of cyclic lipopeptides with synergistic antifungal and antiproliferative activities. They are produced by multiple cyanobacterial genera and comprise two sets of structurally unrelated 11- and 12-residue macrocyclic lipopeptides. Here, we report the discovery of new antifungal laxaphycins from Nostoc sp. UHCC 0702, which we name heinamides, through antimicrobial bioactivity screening. We characterized the chemical structures of eight heinamide structural variants A1-A3 and B1-B5. These variants contain the rare non-proteinogenic amino acids 3-hydroxy-4-methylproline, 4-hydroxyproline, 3-hydroxy-d-leucine, dehydrobutyrine, 5-hydroxyl beta-amino octanoic acid, and O-c…

MULTI-OBJECTIVE OPTIMISATION OF BUILDINGS AND BUILDING CLUSTERS PERFORMANCE: A LIFE CYCLE THINKING APPROACH

2021

Construction of Disjoint Virtual Backbones for Wireless Sensor Networks

2020

A wireless sensor network is a wireless network of sensors aimed at monitoring physical events. It has ingratiated itself into almost all areas of human endeavors. Data dissemination in these networks is quite challenging and is generally accomplished by flooding. But flooding introduces broadcast storm problem due from implosion and overlap. To overcome this, topology management can prescribe a virtual backbone network to which routing is confined. In this paper we propose an algorithm that constructs multiple disjoint virtual backbone networks, using only nodes' locations. The disjointedness makes routing more robust and the network exploitation energy efficient. Simulations show our algo…

Coupled-cluster techniques for computational chemistry: The CFOUR program package

2020

An up-to-date overview of the CFOUR program system is given. After providing a brief outline of the evolution of the program since its inception in 1989, a comprehensive presentation is given of its well-known capabilities for high-level coupled-cluster theory and its application to molecular properties. Subsequent to this generally well-known background information, much of the remaining content focuses on lesser-known capabilities of CFOUR, most of which have become available to the public only recently or will become available in the near future. Each of these new features is illustrated by a representative example, with additional discussion targeted to educating users as to classes of …

A statistical model for predicting the inter-annual variability of birch pollen abundance in Northern and North-Eastern Europe

2018

The paper suggests a methodology for predicting next-year seasonal pollen index (SPI, a sum of daily-mean pollen concentrations) over large regions and demonstrates its performance for birch in Northern and North-Eastern Europe. A statistical model is constructed using meteorological, geophysical and biological characteristics of the previous year). A cluster analysis of multi-annual data of European Aeroallergen Network (EAN) revealed several large regions in Europe, where the observed SPI exhibits similar patterns of the multi-annual variability. We built the model for the northern cluster of stations, which covers Finland, Sweden, Baltic States, part of Belarus, and, probably, Russia and…