Search results for " Complexity"

Self-organization of repetitive spike patterns in developing neuronal networks in vitro

2010

The appearance of spontaneous correlated activity is a fundamental feature of developing neuronal networks in vivo and in vitro. To elucidate whether the ontogeny of correlated activity is paralleled by the appearance of specific spike patterns we used a template-matching algorithm to detect repetitive spike patterns in multi-electrode array recordings from cultures of dissociated mouse neocortical neurons between 6 and 15 days in vitro (div). These experiments demonstrated that the number of spiking neurons increased significantly between 6 and 15 div, while a significantly synchronized network activity appeared at 9 div and became the main discharge pattern in the subsequent div. Repetiti…

Semiglobal practical integral input-to-state stability for a family of parameterized discrete-time interconnected systems with application to sampled…

2015

Abstract Semiglobal practical integral input-to-state stability (SP-iISS) for a feedback interconnection of two discrete-time subsystems is given. We construct a Lyapunov function from the sum of nonlinearly-weighted Lyapunov functions of individual subsystems. In particular, we consider two main cases. The former gives SP-iISS for the interconnected system when both subsystems are semiglobally practically integral input-to-state stable. The latter investigates SP-iISS for the overall system when one of subsystems is allowed to be semiglobally practically input-to-state stable. Moreover, SP-iISS for discrete-time cascades and a feedback interconnection including a semiglobally practically i…

An LMI Approach to Exponential Stock Level Estimation for Large-Scale Logistics Networks

2013

This article aims to present a convex optimization approach for exponential stock level estimation problem of large-scale logistics networks. The model under consideration presents the dependency and interconnections between the dynamics of each single location. Using a Lyapunov function, new sufficient conditions for exponential estimation of the networks are driven in terms of linear matrix inequalities (LMIs). The explicit expression of the observer gain is parameterized based on the solvability conditions. A numerical example is included to illustrate the applicability of the proposed design method.

Clustering-Based Protocol Classification via Dimensionality Reduction

2015

We propose a unique framework that is based upon diffusion processes and other methodologies for finding meaningful geometric descriptions in high-dimensional datasets. We will show that the eigenfunctions of the generated underlying Markov matrices can be used to construct diffusion processes that generate efficient representations of complex geometric structures for high-dimensional data analysis. This is done by non-linear transformations that identify geometric patterns in these huge datasets that find the connections among them while projecting them onto low dimensional spaces. Our methods automatically classify and recognize network protocols. The main core of the proposed methodology…

2014

Large data sets classification is widely used in many industrial applications. It is a challenging task to classify large data sets efficiently, accurately, and robustly, as large data sets always contain numerous instances with high dimensional feature space. In order to deal with this problem, in this paper we present an online Logdet divergence based metric learning (LDML) model by making use of the powerfulness of metric learning. We firstly generate a Mahalanobis matrix via learning the training data with LDML model. Meanwhile, we propose a compressed representation for high dimensional Mahalanobis matrix to reduce the computation complexity in each iteration. The final Mahalanobis mat…

Repeated evolution of soldier sub-castes suggests parasitism drives social complexity in stingless bees

2016

The differentiation of workers into morphological castes represents an important evolutionary innovation that is thought to improve division of labor in insect societies. Given the potential benefits of task-related worker differentiation, it is puzzling that physical worker castes, such as soldiers, are extremely rare in social bees and absent in wasps. Following the recent discovery of soldiers in a stingless bee, we studied the occurrence of worker differentiation in 28 stingless bee species from Brazil and found that several species have specialized soldiers for colony defence. Our results reveal that worker differentiation evolved repeatedly during the last ~ 25 million years and coinc…

Genome-Wide Association Study for Incident Myocardial Infarction and Coronary Heart Disease in Prospective Cohort Studies: The CHARGE Consortium

2016

Background Data are limited on genome-wide association studies (GWAS) for incident coronary heart disease (CHD). Moreover, it is not known whether genetic variants identified to date also associate with risk of CHD in a prospective setting. Methods We performed a two-stage GWAS analysis of incident myocardial infarction (MI) and CHD in a total of 64,297 individuals (including 3898 MI cases, 5465 CHD cases). SNPs that passed an arbitrary threshold of 5×10−6 in Stage I were taken to Stage II for further discovery. Furthermore, in an analysis of prognosis, we studied whether known SNPs from former GWAS were associated with total mortality in individuals who experienced MI during follow-up. Res…

Absorb Bioresorbable Scaffold Versus Xience Metallic Stent for Prevention of Restenosis Following Percutaneous Coronary Intervention in Patients at H…

2019

Abstract Background The advent of bioresorbable vascular scaffolds (BVS) was considered as a potential improvement in percutaneous coronary intervention (PCI) after the groundbreaking development of drug eluting stents (DES). However, the clinical performance, long-term safety and efficacy of BVS in complex coronary lesions remain uncertain. COMPARE ABSORB, a multicenter, single blind, prospective randomized trial, aims to compare the clinical outcomes between the Absorb BVS and Xience everolimus-eluting metallic stent (EES) in patients with coronary artery disease and a high risk of restenosis. Design COMPARE ABSORB is designed to enroll 2100 patients at up to 45 European sites. Enrolled p…

Individual versus provided constructs, cognitive complexity and extremity of ratings in person perception.

1975

.— Bruner & Tagiuri's (1954) concept of implicit personality theory, and Kelly's (1955) theory of personal constructs were used as a basis for a hypothesis that an individual's own constructs mediate more differentiated perceptions of other people than constructs provided by the experimenter. The hypothesis was tested by using four indices of cognitive complexity and one index of extremity of ratings to measure differentiation. The individual constructs were derived by using Reptest. The provided constructs were Semantic Differential and Personality Differential scales. The subjects were 36 psychology students. Two experimenters were employed to control experimenter effects. The data did no…

The convergent validity of four indices of congnitive complexity in person perception. A multi-index multimethod and factor analytical approach.

1975

.— An application of the Campbell and Fiske multimethod-multitrait analysis and factor analysis was used to study the convergent validity of the following indices of cognitive complexity: Bieri's Index, Vannoy's Interaction Variance Measure, Number of Factors, and First Factor Percentage. In the analysis the individual constructs elicited by Reptest were contrasted with two sets of provided constructs, namely Semantic Differential and Personality Differential scales. The subjects were 36 psychology students. The results indicated that the convergent validity of the indices over construct type was low and that the construct type had an effect upon the intercorrelations of different indices o…