Cooperative behavior arises from the interactions of single units that globally produce a complex dynamics in which the system acts as a whole. As an archetype I refer to a flock of birds. As a result of cooperation the whole flock gets special abilities that the single individuals would not have if they were alone. This research work led to the discovery that the function of a flock, and more in general, that of cooperative systems, surprisingly rests on the occurrence of organizational collapses. In this study, I used cooperative systems based on self-propelled particle models (the flock models) which have been proved to be virtually equivalent to sociological network models mimicking the decision making processes (the decision making model). The critical region is an intermediate condition between a highly disordered state and a strong ordered one. At criticality the waiting times distribution density between two consecutive collapses shows an inverse power law form with an anomalous statistical behavior. The scientific evidences are based on measures of information theory, correlation in time and space, and fluctuation statistical analysis. In order to prove the benefit for a system to live at criticality, I made a flock system interact with another similar system, and then observe the information transmission for different disturbance values. I proved that at criticality the transfer of information gets the maximal efficiency. As last step, the flock model has been shown that, despite its simplicity, is sufficiently a realistic model as proved via the use of 3D simulations and computer animations.

This study is about the conditions that may serve as prerequisites for the development of self-regulated learning (SRL). In the context of educational psychology, SRL is not only about the formal aspects of managing one's learning, but also the motivational and affective processes that drive learning, as well as the social and political arena which provide the context for learning. In this study, I will propose that personal, social and political factors can combine in complex ways to produce a learning situation which cannot be addressed adequately without addressing its inherent complexity. I examine some current issues in cognition and cognitive intervention and begin by drawing attention to some problematic aspects concerning children's thinking from an educational and psychological point of view. I review the sociopolitical context in which the conceptualisation and implementation of outcomes based education (OBE) and Curriculum 2005 takes place in South Africa and I also discuss some issues pertaining to the study of cognition from a more psychological point of view. I also address issues of complexity by examining how the meaning of the word has changed in response to changing paradigms in science and psychology and suggest that complexity theory is a metaphor that best fits current knowledge about cognition and problem-solving. Since this study is about the accommodation of complexity in cognitive intervention, an important feature of this study concerns a specific characteristic of complex systems, namely chaos. Chaos allows self-organisation in a complex system and is also the main reason why change in a chaotic system is non-linear and unpredictable. It is generally believed that complex systems need to be studied in an unrestricted context if one is to observe those features that lend the system its chaotic character. In the context of the present study, complexity and chaos are hypothesised to be necessary prerequisites for the development of children as self-regulated learners because they form the mechanisms by which cognitive change becomes possible. The research was carried out in two phases. In Phase One of the research, classroom observations were made and the Mediational Behaviour Observation Scale (MBOS) was especially designed for this purpose. Phase Two of the research was carried out in an intervention context by means of a design experiment. Verbatim transcriptions were made of the interaction between the researcher and the learners in nine group sessions which formed part of the design experiment. To enhance the reliability and validity of the data, re-coding and intra-coding consistencies were calculated before the data were analysed. The re-coding consistencies ensured that the subsequent analysis of patterns would enable reliable conclusions to be drawn, whereas the intra-coding consistencies helped to refine the MBOS by indicating which categories may have been flawed, poorly described or impure. As such, the examination of the intra-code consistencies could perhaps be likened to factor analysis which resulted in some codes being merged and others being rejected. These data were used to construct a revised and shortened version of the MBOS. Some of the more important results of the data-analysis on the design experiment indicated that when complexity and chaos are encouraged in cognitive intervention, some of the mediator behaviours that are most likely to be observed are (i) guidance of the way in which learners execute tasks, (ii) attempts to engage learners in group discussions, (iii) modelling or requiring learners to explore tasks systematically, (iv) positive interactions such as acknowledging responses or praising learners, (v) modelling analytical thinking and (vi) probing of learners' responses. / Dissertation (PhD(Educational Psychology))--University of Pretoria, 2003. / Educational Psychology / unrestricted

Executive Functioning (EF) such as planning, organization, attention, and self-control, has a high impact on quality of life, but is vulnerable to aging.  One factor that may help to maintain and strengthen EF is Occupational Complexity (OC), the degree of complexity in one’s primary occupation in life.  Higher OC has been associated with higher EF performance in old age.  However, few of these findings were based on the latest occupational taxonomy (Occupational Network Information; O*NET) that may best reflect todays jobs.  The current study adds to this scarce body of knowledge by examining EF, as conceptualized by Miyake, et al. (2000), and OC, using O*NET.  Data from the Umeå Healthy Aging longitudinal study database was analyzed using Structural Equation Modeling to test the relationship between EF, OC, and their component constructs.  Results from 227 participants showed that individuals with higher OC had higher EF in late life, but this association was not statistically significant (nearly all p values &lt;.05), suggesting that there was no such association in the current sample. / Executive Functioning (EF) som planering, organisation, uppmärksamhet och självkontroll har stor inverkan på livskvaliteten, men är sårbara för åldrande. En faktor som kan bidra till att upprätthålla och stärka EF är Occupational Complexity (OC), graden av komplexitet i ens främsta yrke i livet. Högre OC har förknippats med högre EF-prestanda i ålderdom. Emellertid var få av dessa resultat baserade på den senaste yrkes taxonomin (Occupational Network Information; O*NET) som bäst kan återspegla dagens jobb. Den nuvarande studien ökar denna knappa kunskapskomponent genom att undersöka EF, som konceptualiserats av Miyake, et al. (2000) och OC med O*NET. Data från Umeå Healthy Aging longitudinell studiedatabas analyserades med hjälp av strukturell ekvationsmodellering för att testa förhållandet mellan EF, OC och deras komponentkonstruktioner. Resultat från 227 deltagare visade att individer med högre OC hade högre EF under sent liv, men denna förening var inte statistiskt signifikant (nästan alla p-värden &lt;0,05), vilket tyder på att det inte fanns någon sådan associering i det aktuella urvalet. / <p>Due to the Coronavirus crisis, in-person meetings were replaced with video conferences, via a computer program called Zoom.</p>

NR 20140805

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The problem of extending partial representations for an interval graph asks, whether it is possible to extend a given representation of some vertices to a valid representation of the entire graph. In this thesis we extend the recent result of Klavík et al. who proved REPEXT can be decided for proper and unit interval graphs in polynomial time. We describe properties of PI± and U± graphs and their representations and present algorithms deciding REPEXT for these classes in polynomial time. In the process, we characterize relations between the K1,3's in a graph and show that we can decide the open vertex of every K1,3. We also define notions of representation of the same order type and locally similar representations as well as intervals forced and locally forced to be closed (open) that are essential for extending partial representations when multiple types of intervals can occur in the same representation. We characterize intervals forced and locally forced to be closed (open) in a U± graph using integer gaps in the pre-representation and we construct lower bounds for the rightmost endpoint of a component in polynomial time.

In this thesis, we study the discrete logarithm problem in the context of TFNP - the complexity class of search problems with a syntactically guaranteed existence of a solution for all instances. Our main results show that suitable variants of the discrete logarithm problem, which we call Index and DLog, are complete for the classes PPP and PWPP, respectively. Additionally, our reductions provide new structural insights into PWPP by establishing two new PWPP-complete problems. First, the problem Dove, a relaxation of the PPP-complete problem Pigeon. Dove is the first PWPP-complete problem not defined in terms of an explicitly shrinking function. Second, the problem Claw, a total search problem capturing the computational complexity of breaking claw-free permuta- tions. In the context of TFNP, the PWPP-completeness of Claw matches the known intrinsic relationship between collision-resistant hash functions and claw-free permuta- tions established in the cryptographic literature. 1

The thesis formulates and proves a witnessing theorem for SPV -provable formulas in the form ∀x∃yA(x, y) where A corresponds to a polynomial time decidable relation. By SPV we understand an extension of the theory TPV (the universal theory of N in the language representing polynomial algorithms) by additional axioms ensuring the existence of a minimum of a linear ordering defined by a polynomial time decidable relation on an initial segment. As these additional axioms are not universal sentences, the theory SPV requires nontrivial use of witnessing Herbrand's and KPT theorems which have direct application only for universal theories. Based on the proven witnessing theorem, we derive a NP search problem characterizing complexity of finding y for a given x such that A(x, y). A part of the thesis is dedicated to arguments supporting the conjecture that SPV is strictly stronger than TPV . 1

Conflict researchers have validated many different theories on the causes of organized violence, but there are significant gaps in knowledge concerning how these theories interact with one another. In this thesis, I identify a body of the most prominent theories of organized violence and model them in an environment suitable for capturing these complex interactions. I formulate six causal categories to which these theories belong: Geography; Economy; Conflict History &amp; Insecurity; Liberty &amp; Inclusion; Natural Resources; and Structures of Governance. I then construct a cross-national, time-series sample of country-year observations and create a general model of organized violence using a machine learning technique called Classification and Regression Trees (CART). The results from this first model indicates a substantial negative effect owing to Peace Years, a count of the number of years since the country last experienced an internal conflict. Subsequently, I construct three more models, each investigating different subsets of country-year observations based on their Peace Years value. My models indicate that the country-years most likely to experience a high number of deaths from organized violence are those where conflict occurred in the previous year, the population size is high, and the net rate of male secondary school enrollment is low. The models also reveal several novel results under the presence of certain conditions, including: nonlinear relationships between deaths from organized violence and both oil exports and mass education; and a negative relationship between economic inequality and deaths from organized violence, wherein higher inequality results in fewer deaths. These findings highlight the importance of complexity-based modeling for both future conflict research and policymaking oriented towards violence reduction.

Under what configuration of conditions do ethno-territorial conflicts escalate, and under what configurations of conditions is conflict avoided between a minority and the centre in multi- ethnic states? This dissertation employs qualitative comparative analysis (QCA) in order to capture the causal patterns of conflict escalation and peace preservation. By simultaneously analysing the causes of conflict and the conditions of peace, this dissertation bridges a significant gap in the existing literature that assumes causal linearity and unifinality. The QCA analysis this dissertation conducts is grounded in empirical evidence from the South Caucasus where, after the disintegration of the Soviet Union, three newly independent states emerged and grappled with the accommodation of ethnic-minorities and their evolving identities. The QCA analysis reveals that, contrary to the popular premise that regional autonomy is "an effective antidote" for ethno-territorial wars, autonomy in the South Caucasus was conducive to conflict and the lack of autonomy was conducive to peace. Nevertheless, this dissertation does not suggest that autonomy on its own can explain the complexity of inter-ethnic relations. Rather, it argues that there were multiple configurations of conditions that interacted to produce...