16 resultados para Adaptiveness


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When proposing primary control (changing the world to fit self)/secondary control (changing self to fit the world) theory, Weisz et al. (1984) argued for the importance of the “serenity to accept the things I cannot change, the courage to change the things I can” (p. 967), and the wisdom to choose the right control strategy that fits the context. Although the dual processes of control theory generated hundreds of empirical studies, most of them focused on the dichotomy of PC and SC, with none of these tapped into the critical concept: individuals’ ability to know when to use what. This project addressed this issue by using scenario questions to study the impact of situationally adaptive control strategies on youth well-being. To understand the antecedents of youths’ preference for PC or SC, we also connected PCSC theory with Dweck’s implicit theory about the changeability of the world. We hypothesized that youths’ belief about the world’s changeability impacts how difficult it was for them to choose situationally adaptive control orientation, which then impacts their well-being. This study included adolescents and emerging adults between the ages of 18 and 28 years (Mean = 20.87 years) from the US (n = 98), China (n = 100), and Switzerland (n = 103). Participants answered a questionnaire including a measure of implicit theories about the fixedness of the external world, a scenario-based measure of control orientation, and several measures of well-being. Preliminary analyses of the scenario-based control orientation measures showed striking cross-cultural similarity of preferred control responses: while for three of the six scenarios primary control was the predominately chosen control response in all cultures, for the other three scenarios secondary control was the predominately chosen response. This suggested that youths across cultures are aware that some situations call for primary control, while others demand secondary control. We considered the control strategy winning the majority of the votes to be the strategy that is situationally adaptive. The results of a multi-group structural equation mediation model with the extent of belief in a fixed world as independent variable, the difficulties of carrying out the respective adaptive versus non-adaptive control responses as two mediating variables and the latent well-being variable as dependent variable showed a cross-culturally similar pattern of effects: a belief in a fixed world was significantly related to higher difficulties in carrying out the normative as well as the non-normative control response, but only the difficulty of carrying out the normative control response (be it primary control in situations where primary control is normative or secondary control in situations where secondary control is normative) was significantly related to a lower reported well-being (while the difficulty of carrying out the non-normative response was unrelated to well-being). While previous research focused on cross-cultural differences on the choice of PC or SC, this study shed light on the universal necessity of applying the right kind of control to fit the situation.

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A major challenge in the engineering of complex and critical systems is the management of change, both in the system and in its operational environment. Due to the growing of complexity in systems, new approaches on autonomy must be able to detect critical changes and avoid their progress towards undesirable states. We are searching for methods to build systems that can tune the adaptability protocols. New mechanisms that use system-wellness requirements to reduce the influence of the outer domain and transfer the control of uncertainly to the inner one. Under the view of cognitive systems, biological emotions suggests a strategy to configure value-based systems to use semantic self-representations of the state. A method inspired by emotion theories to causally connect to the inner domain of the system and its objectives of wellness, focusing on dynamically adapting the system to avoid the progress of critical states. This method shall endow the system with a transversal mechanism to monitor its inner processes, detecting critical states and managing its adaptivity in order to maintain the wellness goals. The paper describes the current vision produced by this work-in-progress.

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A major challenge in the engineering of complex and critical systems is the management of change, both in the system and in its operational environment. Due to the growing of complexity in systems, new approaches on autonomy must be able to detect critical changes and avoid their progress towards undesirable states. We are searching for methods to build systems that can tune the adaptability protocols. New mechanisms that use system-wellness requirements to reduce the influence of the outer domain and transfer the control of uncertainly to the inner one. Under the view of cognitive systems, biological emotions suggests a strategy to configure value-based systems to use semantic self-representations of the state. A method inspired by emotion theories to causally connect to the inner domain of the system and its objectives of wellness, focusing on dynamically adapting the system to avoid the progress of critical states. This method shall endow the system with a transversal mechanism to monitor its inner processes, detecting critical states and managing its adaptivity in order to maintain the wellness goals. The paper describes the current vision produced by this work-in-progress.

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Behavioral adaptiveness to different situations as well as behavioral individuality result from the interrelations between environmental sitmuli and the responses of an organism.These kind of interrelationships also shape the neural circuits as well as characterize the plasticity and the neural individuality of the organism. Studies on neural plasticity may analyze changes in neural circuitry after environmental manipulations or changes in behavior after lesions in the nervous system. Issues on neural plasticity and recovery of function refer both to physiology and behavior as well as to the subjacent mechanisms related to morphology, biochemistry and genetics. They may be approached at the systemic, behavioral, cellular and molecular levels. This work intends to characterize these kinds of studies pointing to their relations with the analyis of behavior and learning.The analysis of how the environmental-organismic interrelationships affect the neural substrates of behavior is pointed as a very stimulating area for investigation.

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Ways to enhance research into coping have been suggested by Lazarus (2000). The issues of adaptiveness and conceptual structure of coping (Cramer, 1998; Skinner et al., 2003) are particularly relevant; thus, this study addresses them in a clinical research setting. A total of 30 inpatients presenting with Bipolar Affective Disorder (BD) have been interviewed twice, as well as the participants of a matched control group (N = 30). Self-report (CISS) and observerrater methods (CAP) of coping have been applied: low correlations were found between the instruments. Coping specificities in BD have been identified: opposition and support-seeking are most frequently practiced by BD patients, in comparison with controls. No significant link has been found between coping processes, symptom level and the therapeutic alliance. This study lends support for a quantitative definition of coping adaptiveness which is discussed, along with clinical implications on psychological treatments of BD (German J Psychiatry 2009; 12: 19-27).

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Abstract This thesis proposes a set of adaptive broadcast solutions and an adaptive data replication solution to support the deployment of P2P applications. P2P applications are an emerging type of distributed applications that are running on top of P2P networks. Typical P2P applications are video streaming, file sharing, etc. While interesting because they are fully distributed, P2P applications suffer from several deployment problems, due to the nature of the environment on which they perform. Indeed, defining an application on top of a P2P network often means defining an application where peers contribute resources in exchange for their ability to use the P2P application. For example, in P2P file sharing application, while the user is downloading some file, the P2P application is in parallel serving that file to other users. Such peers could have limited hardware resources, e.g., CPU, bandwidth and memory or the end-user could decide to limit the resources it dedicates to the P2P application a priori. In addition, a P2P network is typically emerged into an unreliable environment, where communication links and processes are subject to message losses and crashes, respectively. To support P2P applications, this thesis proposes a set of services that address some underlying constraints related to the nature of P2P networks. The proposed services include a set of adaptive broadcast solutions and an adaptive data replication solution that can be used as the basis of several P2P applications. Our data replication solution permits to increase availability and to reduce the communication overhead. The broadcast solutions aim, at providing a communication substrate encapsulating one of the key communication paradigms used by P2P applications: broadcast. Our broadcast solutions typically aim at offering reliability and scalability to some upper layer, be it an end-to-end P2P application or another system-level layer, such as a data replication layer. Our contributions are organized in a protocol stack made of three layers. In each layer, we propose a set of adaptive protocols that address specific constraints imposed by the environment. Each protocol is evaluated through a set of simulations. The adaptiveness aspect of our solutions relies on the fact that they take into account the constraints of the underlying system in a proactive manner. To model these constraints, we define an environment approximation algorithm allowing us to obtain an approximated view about the system or part of it. This approximated view includes the topology and the components reliability expressed in probabilistic terms. To adapt to the underlying system constraints, the proposed broadcast solutions route messages through tree overlays permitting to maximize the broadcast reliability. Here, the broadcast reliability is expressed as a function of the selected paths reliability and of the use of available resources. These resources are modeled in terms of quotas of messages translating the receiving and sending capacities at each node. To allow a deployment in a large-scale system, we take into account the available memory at processes by limiting the view they have to maintain about the system. Using this partial view, we propose three scalable broadcast algorithms, which are based on a propagation overlay that tends to the global tree overlay and adapts to some constraints of the underlying system. At a higher level, this thesis also proposes a data replication solution that is adaptive both in terms of replica placement and in terms of request routing. At the routing level, this solution takes the unreliability of the environment into account, in order to maximize reliable delivery of requests. At the replica placement level, the dynamically changing origin and frequency of read/write requests are analyzed, in order to define a set of replica that minimizes communication cost.

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Catholicism has built up a legalistic religion based on two pillars: salvation by works and 'auricular' confession of sins to a priest with judicial functions. Since the Reformation, many consider auricular confession inferior to less institutional and more individual conceptions of faith. This article analyzes how all these historical solutions trade off specialization advantages against exchange costs to produce moral enforcement. After showing the behavioral foundations of confession and the adaptiveness of its historical evolution, it tests hypotheses on its efficacy, exploitation and opportunity cost. Econometric evidence supports the efficacy but not the exploitative character of Catholic confession. It also explains its secular decline as a consequence of two factors. First, the rise in education, which makes moral self-enforcement less costly. Second, the productivity gap suffered by confession, given its necessarily interpersonal nature.

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This PhD thesis addresses the issue of scalable media streaming in large-scale networking environments. Multimedia streaming is one of the largest sink of network resources and this trend is still growing as testified by the success of services like Skype, Netflix, Spotify and Popcorn Time (BitTorrent-based). In traditional client-server solutions, when the number of consumers increases, the server becomes the bottleneck. To overcome this problem, the Content-Delivery Network (CDN) model was invented. In CDN model, the server copies the media content to some CDN servers, which are located in different strategic locations on the network. However, they require heavy infrastructure investment around the world, which is too expensive. Peer-to-peer (P2P) solutions are another way to achieve the same result. These solutions are naturally scalable, since each peer can act as both a receiver and a forwarder. Most of the proposed streaming solutions in P2P networks focus on routing scenarios to achieve scalability. However, these solutions cannot work properly in video-on-demand (VoD) streaming, when resources of the media server are not sufficient. Replication is a solution that can be used in these situations. This thesis specifically provides a family of replication-based media streaming protocols, which are scalable, efficient and reliable in P2P networks. First, it provides SCALESTREAM, a replication-based streaming protocol that adaptively replicates media content in different peers to increase the number of consumers that can be served in parallel. The adaptiveness aspect of this solution relies on the fact that it takes into account different constraints like bandwidth capacity of peers to decide when to add or remove replicas. SCALESTREAM routes media blocks to consumers over a tree topology, assuming a reliable network composed of homogenous peers in terms of bandwidth. Second, this thesis proposes RESTREAM, an extended version of SCALESTREAM that addresses the issues raised by unreliable networks composed of heterogeneous peers. Third, this thesis proposes EAGLEMACAW, a multiple-tree replication streaming protocol in which two distinct trees, named EAGLETREE and MACAWTREE, are built in a decentralized manner on top of an underlying mesh network. These two trees collaborate to serve consumers in an efficient and reliable manner. The EAGLETREE is in charge of improving efficiency, while the MACAWTREE guarantees reliability. Finally, this thesis provides TURBOSTREAM, a hybrid replication-based streaming protocol in which a tree overlay is built on top of a mesh overlay network. Both these overlays cover all peers of the system and collaborate to improve efficiency and low-latency in streaming media to consumers. This protocol is implemented and tested in a real networking environment using PlanetLab Europe testbed composed of peers distributed in different places in Europe.

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As a consequence of the deleterious effects of parasites on host fitness, hosts have evolved responses to minimize the negative impact of parasite infection. Facultative parasite-induced responses are favoured when the risk of infection is unpredictable and host responses are costly. In vertebrates, induced responses are generally viewed as being adaptive, although evidence for fitness benefits arising from these responses in natural host populations is lacking. Here we provide experimental evidence for direct reproductive benefits in flea-infested great tit nests arising from exposure during egg production to fleas. In the experiment we exposed a group of birds to fleas during egg laying (the exposed group), thereby allowing for induced responses, and kept another group free of parasites (the unexposed group) over the same time period. At the start of incubation, we killed the parasites in both groups and all nests were reinfested with fleas. If induced responses occur and are adaptive, we expect that birds of the exposed group mount earlier responses and achieve higher current reproductive success than birds in the unexposed group. In agreement with this prediction, our results show that birds with nests infested during egg-laying have (i) fewer breeding failures and raise a higher proportion of hatchlings to hedging age; () offspring that reach greater body mass, grow longer feathers, and hedge earlier, and (iii) a higher number of recruits and first-year grandchildren than unexposed birds. Flea reproduction and survival did not differ significantly between the two treatments. These results provide the first evidence for the occurrence and the adaptiveness of induced responses against a common ectoparasite in a wild population of vertebrates. [References: 50]

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Primary control is defined as changing the world to fit the self, while secondary control is defined as changing the self to fit the world. To understand why different individuals prefer different kinds of control processes, we proposed a research project looking at US, German and Indian young adults. We hypothesize that theories of self and the world (fixed vs. malleable; Dweck, 1999) affect the prevailing mode of control used. Furthermore, adolescents’ cultural background is assumed to affect their self-world theories as well as the adaptiveness of specific modes of control. For example, in the US, where the self is tended to be seen as fixed and the world as malleable, primary control prevails and is more adaptive than secondary control while the reverse is expected for India. We present the theoretical outline and methodology of the study as well as first results.

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This paper analyses the adaptiveness of the Public Agricultural Extension Services (PAES) to climate change. Existing literature, interviews and group discussions among PAES actors in larger Makueni district, Kenya, provided the data for the analyses. The findings show that the PAES already have various elements of adaptiveness in its policies, approaches and methods of extension provision. However, the hierarchical structure of the PAES does not augur well for self-organisation at local levels of extension provision, especially under conditions of abrupt change which climate change might trigger. Most importantly, adpativeness presupposes adaptive capacity but the lack of resources in terms of funding for extension, limited mobility of extension officers, the low extension staff/farmer ratio, the aging of extension staff and significant dependence on donor funding limits the adaptiveness of the PAES. Accordingly criteria and indicators were identified in literature with which an initial assessement of the adaptiiveneess of PAES was conducted. However this assessment framework needs to be improved and future steps will integrate more specific inputs from actors in PAES in order to make the framework operational.

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The radiation of cichlid fishes in the African great lakes is often described as adaptive, because, at a superficial level, cichlid fishes seem adapted to the ecological niches they occupy. However, adaptiveness has rarely been studied. We investigated to what extent island populations of three species of the rock-dwelling genus Neochromis, endemic to Lake Victoria, are adapted anatomically to exploit locally abundant resources. Specifically, we asked whether different resource environments were reflected in differences in the feeding apparatus, both within species and between species. In populations of two specialized biters, the algae scrapers N. rufocaudalis and N. omnicaeruleus, the biting force of the lower jaw increased with increasing amount of items that require biting in the diet. N. greenwoodi is a less specialized biter; we found differences between two populations in the hyoid position and in the premaxilla that enhance suction feeding. These adaptations were related to the amount of items requiring suction. Comparing across three sympatric pairs of species, in each case different diets were reflected in differences in anatomy.

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The software underpinning today’s IT systems needs to adapt dynamically and predictably to rapid changes in system workload, environment and objectives. We describe a software framework that achieves such adaptiveness for IT systems whose components can be modelled as Markov chains. The framework comprises (i) an autonomic architecture that uses Markov-chain quantitative analysis to dynamically adjust the parameters of an IT system in line with its state, environment and objectives; and (ii) a method for developing instances of this architecture for real-world systems. Two case studies are presented that use the framework successfully for the dynamic power management of disk drives, and for the adaptive management of cluster availability within data centres, respectively.

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Heuristics, simulation, artificial intelligence techniques and combinations thereof have all been employed in the attempt to make computer systems adaptive, context-aware, reconfigurable and self-managing. This paper complements such efforts by exploring the possibility to achieve runtime adaptiveness using mathematically-based techniques from the area of formal methods. It is argued that formal methods @ runtime represents a feasible approach, and promising preliminary results are summarised to support this viewpoint. The survey of existing approaches to employing formal methods at runtime is accompanied by a discussion of their challenges and of the future research required to overcome them. © 2011 Springer-Verlag.

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In the discussion - World-Class Service - by W. Gerald Glover, Associate Professor, Restaurant, Hotel and Resort Management at Appalachian State University and Germaine W. Shames, Hilton International, New York, Glover and Shames initially state: “Providing world-class service to today's traveler may be the key for hospitality managers in the current competitive market. Although an ideal, this type of service provides a mandate for culturally aware managers. The authors provide insight into several areas of cultures in collision.” Up to the time this essay is written, the authors point to a less-than-ideal level of service as being the standard in the hospitality industry and experience. “Let's face it - if we're ever to resurrect service, it will not be by going back to anything,” Glover and Shames exclaim. “Whatever it was we did back then has contributed to the dilemma in which we find ourselves today, handicapped by a reactive service culture in an age that calls for adaptiveness and global strategies,” the authors fortify that thought. In amplifying the concept of world-class service Glover and Shames elaborate: “World-class service is an ideal. Proactive and adaptive, world-class service feels equally right to the North American dignitary occupying the Presidential Suite, and the Japanese tourist staying in a standard room in the same hotel.” To bracket that model the authors offer: “At a minimum, it is service perceived by each customer as appropriate and adequate. At its best, it may also make the customer feel at home, among friends, or pampered. Finally, it is service as if culture matters,” Glover and Shames expand and capture the rule of world-class service. Glover and Shames consider the link between cultures and service an imperative one. They say it is a principle lost on most hospitality managers. “Most [managers] have received service management education in the people are people school that teaches us to disregard cultural differences and assume that everyone we manage or serve is pretty much like ourselves,” say Glover and Shames. “Is it any wonder that we persist in setting service standards, marketing services, and managing service staff not only as if culture didn't matter, but as if it didn't exist?!” To offer legitimacy to their effort Glover and Shames present the case of the Sun and Sea Hotel, a 500-room first class hotel located on the outskirts of the capital city of a small Caribbean island nation. It is a bit difficult to tell whether this is a dramatization or a reality. It does, however, serve to illustrate their point in regard to management’s cognizance, or lack thereof, of culture when it comes to cordial service and guest satisfaction. Even more apropos is the tale of the Palace Hotel, “…one of the grande dames of hospitality constructed in the boom years of the 1920s in a mid-sized Midwestern city in the United States.” The authors relate what transpired during its takeover in mid-1980 by a U.S.-based international hotel corporation. The story makes for an interesting and informative case study.