Particle swarm optimization : understanding order-2 stability guarantees

This paper’s primary aim is to provide clarity on which guarantees about particle stability can actually be made. The particle swarm optimization algorithm has undergone a considerable amount of theoretical analysis. However, with this abundance of theory has come some terminological inconstancies, and as a result it is easy for a practitioner to be misguided by overloaded terminology. Specifically, the criteria for both order-1 and order-2 stability are well studied, but the exact definition of order-2 stability is not consistent amongst researchers. A consequence of this inconsistency in terminology is that the existing theory may in fact misguide practitioners instead of assisting them. In this paper it is theoretically and empirically demonstrated which practical guarantees can in fact be made about particle stability. Specifically, it is shown that the definition of order-2 stability which accurately reflects PSO behavior is that of convergence in second order moment to a constant, and not to zero.http://link.springer.combookseries/5582020-03-30hj2020Computer Scienc

Solving large 0–1 multidimensional knapsack problems by a new simplified binary artificial fish swarm algorithm

The artificial fish swarm algorithm has recently been emerged in continuous global optimization. It uses points of a population in space to identify the position of fish in the school. Many real-world optimization problems are described by 0-1 multidimensional knapsack problems that are NP-hard. In the last decades several exact as well as heuristic methods have been proposed for solving these problems. In this paper, a new simpli ed binary version of the artificial fish swarm algorithm is presented, where a point/ fish is represented by a binary string of 0/1 bits. Trial points are created by using crossover and mutation in the different fi sh behavior that are randomly selected by using two user de ned probability values. In order to make the points feasible the presented algorithm uses a random heuristic drop item procedure followed by an add item procedure aiming to increase the profit throughout the adding of more items in the knapsack. A cyclic reinitialization of 50% of the population, and a simple local search that allows the progress of a small percentage of points towards optimality and after that refines the best point in the population greatly improve the quality of the solutions. The presented method is tested on a set of benchmark instances and a comparison with other methods available in literature is shown. The comparison shows that the proposed method can be an alternative method for solving these problems.The authors wish to thank three anonymous referees for their comments and valuable suggestions to improve the paper. The first author acknowledges Ciˆencia 2007 of FCT (Foundation for Science and Technology) Portugal for the fellowship grant C2007-UMINHO-ALGORITMI-04. Financial support from FEDER COMPETE (Operational Programme Thematic Factors of Competitiveness) and FCT under project FCOMP-01-0124-FEDER-022674 is also acknowledged

Human Mesenchymal Stem Cells Self-Renew and Differentiate According to a Deterministic Hierarchy

BACKGROUND:Mesenchymal progenitor cells (MPCs) have been isolated from a variety of connective tissues, and are commonly called "mesenchymal stem cells" (MSCs). A stem cell is defined as having robust clonal self-renewal and multilineage differentiation potential. Accordingly, the term "MSC" has been criticised, as there is little data demonstrating self-renewal of definitive single-cell-derived (SCD) clonal populations from a mesenchymal cell source. METHODOLOGY/PRINCIPAL FINDINGS:Here we show that a tractable MPC population, human umbilical cord perivascular cells (HUCPVCs), was capable of multilineage differentiation in vitro and, more importantly, contributed to rapid connective tissue healing in vivo by producing bone, cartilage and fibrous stroma. Furthermore, HUCPVCs exhibit a high clonogenic frequency, allowing us to isolate definitive SCD parent and daughter clones from mixed gender suspensions as determined by Y-chromosome fluorescent in situ hybridization. CONCLUSIONS/SIGNIFICANCE:Analysis of the multilineage differentiation capacity of SCD parent clones and daughter clones enabled us to formulate a new hierarchical schema for MSC self-renewal and differentiation in which a self-renewing multipotent MSC gives rise to more restricted self-renewing progenitors that gradually lose differentiation potential until a state of complete restriction to the fibroblast is reached

The Effective Medicinal plants in Cataract Treatment: An Inquiry in Persian Medicine Resources (4-13th century AH)

BACKGROUND AND OBJECTIVE: Cataract is a kind of eye disease that starts with blurriness of eye lens and the vision is disrupted as the opacity and cloudiness of the lens increases. Iranian people knew cataract as "Nozoul-al-ma" (water fall) and they believed that this disease was an effect of the moisture that accumulates between lens and cornea. Currently, surgery is the only way to restore vision in people with cataract. However, effective medical therapy can reduce the costs and risks of surgery. The purpose of this study is to find the effective medicinal plants in cataract treatment. METHODS: This review article based on library research methods was conducted in three steps (keyword determination, analysis of resources, scoring and arrangement) by investigating Persian medicine references. In this study, seven books from 4-13th century AH were studied. The results were scored from 1 to 3 based on implicit or undecided statement, single citation, direct statement and emphatic effect statement. FINDINGS: 36 medicinal plants were found and 11 plants (Ferula assafoetida, Ferula Persica, Foeniculum Vulgare, Cyclamen europaeum, Allium cepa, Euphorbia resinifera, Isatis tinctoria, Zataria multiflora , Olea europaea, Caesalpinia bonduc, Commiphora opobalsamum) obtained the highest scores. CONCLUSION: The plants that obtained the highest scores were probably the most prominent drugs for the treatment of cataract in 4-13th century AH. Frequent use of these drugs in recent centuries may indicate their appropriate effect on cataract. However, more clinical researches are required to confirm that

Improved exploration and exploitation in particle swarm optimization

Exploration and exploitation are analyzed in Particle Swarm Optimization (PSO) through a set of experiments that make new measurements of these key features. Compared to analyses on diversity and particle trajectories, which focus on particle motions and their potential to achieve exploration and exploitation, our analysis also focuses on the pbest positions that reflect the actual levels of exploration and exploitation that have been achieved by PSO. A key contribution of this paper is a clear criterion for when restarting particles can be expected to be a useful strategy in PSO

Metaheuristics for Discovering Favourable Continuous Intravenous Insulin Rate Protocols from Historical Patient Data

Metaheuristic search algorithms are used to develop new protocols for optimal intravenous insulin infusion rate recommendations in scenarios involving hospital in-patients with Type 1 Diabetes. Two metaheuristic search algorithms are used, namely, Particle Swarm Optimization and Covariance Matrix Adaption Evolution Strategy. The Glucose Regulation for Intensive Care Patients (GRIP) serves as the starting point of the optimization process. We base our experiments on a methodology in the literature to evaluate the favorability of insulin protocols, with a dataset of blood glucose level/insulin infusion rate time series records from 16 patients obtained from the Waikato District Health Board. New and significantly better insulin infusion strategies than GRIP are discovered from the data through metaheuristic search. The newly discovered strategies are further validated and show good performance against various competitive benchmarks using a virtual patient simulator

Optimising tours for the weighted traveling salesperson problem and the traveling thief problem: a structural comparison of solutions

The Traveling Salesperson Problem (TSP) is one of the bestknown combinatorial optimisation problems. However, many real-world problems are composed of several interacting components. The Traveling Thief Problem (TTP) addresses such interactions by combining two combinatorial optimisation problems, namely the TSP and the Knapsack Problem (KP). Recently, a new problem called the node weight dependent Traveling Salesperson Problem (W-TSP) has been introduced where nodes have weights that influence the cost of the tour. In this paper, we compare W-TSP and TTP. We investigate the structure of the optimised tours for W-TSP and TTP and the impact of using each others fitness function. Our experimental results suggest (1) that the W-TSP often can be solved better using the TTP fitness function and (2) final W-TSP and TTP solutions show different distributions when compared with optimal TSP or weighted greedy solutions.Jakob Bossek, Aneta Neumann, and Frank Neuman

Ricerca per lo sviluppo di un modulo abitativo di emergenza sostenibile a carattere provvisorio

PROGETTO DI RICERCA La ricerca ha lo scopo di sviluppare e definire un sistema residenziale trasferibile basato su moduli di base assemblabili, facilmente trasportabili interamente costruiti in materiale plastico e progettati per poter acquistare peso e massa attraverso il riempimento in opera con acqua o altri materiali, garantendo una ampia adattabilità alle diverse condizioni geografiche e climatiche. Il progetto prevede il ricorso ad elementi accessori destinati alla produzione di energia elettrica tramite l'utilizzo di fonti di energia rinnovabili (impianto fotovoltaico da 1,5 kwhp in modalità stand-alone) che consentano sin dalla prima installazione una parziale autosufficienza energetica al modulo, nonchè l'utilizzo di materiali e tecnologie che garantiscano un consumo energetico complessivo tale da rendere possibile una certificazione energetica del manufatto in categoria 'A' o 'B', secondo gli standard prestazionali fissati dall'Agenzia Casa Clima in relazione alle diverse zone climatiche del territorio nazionale, in ottemperanza alla normativa vigente in materia di risparmio energetico. DEFINIZIONE DEL PROGETTO DI RICERCA Il progetto prevede un approfondimento progettuale il cui risultato consentirà di condurre degli approfondimenti tecnici e delle simulazione attraverso l'utilizzo di software specifici e di un modello virtuale al fine di verificare e meglio definire il comportamento del modulo abitativo rispetto ai parametri prestazionali che la ricerca si prefigge di raggiungere in termini di sostenibilità ed efficienza energetica. sul medesimo modello verrà condotta la verifica per la certificazione energetica secondo i parametri e attraverso l'applicazione delle procedure imposte dallo standard Casaclima. AMBITI COMMERCIALI DI DIFFUSIONE DEL PRODOTTO Il modulo abitativo è pensato per fronteggiare le emergenze abitative connesse a calamità naturali, ma puòovare un facile impiego anche nei campi della ricettività turistico-alberghiera, nell'ambito degli insediamenti da cantiere e dei servizi pubblici e privati a carattere mobile. PARTNER ISTITUZIONALI: -Università degli Studi di Roma Tre: la ricerca rientra nell'attività di ricerca sviluppata dalla Scuola dottorale XXI ciclo, Culture della Trasformazione e della città e del territorio, Sezione Progetto Urbano e Sostenibile del DIPSA (Dipartimento di Progettazione e Studio dell'Architettura) Facoltà di Architettura dell'Università degli Studi di Roma Tre. PARTNER INDUSTRIALI: -GPS Srl: Azienda specializzata nella costruzione di stampi e attrezzature per la produzione di articoli in plastica (tecnopolimeri e termoindurenti), si occuperà della produzione del prototipo, la cui scocca è realizzata interamente in materiale plastico. -DEA Srl: azienda operante a livello nazionale nel campo delle energie alternative per la commercializzazione, l'installazione e il collaudo di prodotti altamente specializzati sia in funzione del risparmio energetico che per la salvaguardia dell'ambiente. Si occuperà della fornitura dell'impianto fotovoltaico a servizio del modulo abitativo