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Assessing influence in survival data with a cure fraction and covariates

ORTEGA, Edwin M. M.; CANCHO, Vicente G.; LACHOS, Victor Hugo
Fonte: INST ESTADISTICA CATALUNYA-IDESCAT Publicador: INST ESTADISTICA CATALUNYA-IDESCAT
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.01%
Diagnostic methods have been an important tool in regression analysis to detect anomalies, such as departures from error assumptions and the presence of outliers and influential observations with the fitted models. Assuming censored data, we considered a classical analysis and Bayesian analysis assuming no informative priors for the parameters of the model with a cure fraction. A Bayesian approach was considered by using Markov Chain Monte Carlo Methods with Metropolis-Hasting algorithms steps to obtain the posterior summaries of interest. Some influence methods, such as the local influence, total local influence of an individual, local influence on predictions and generalized leverage were derived, analyzed and discussed in survival data with a cure fraction and covariates. The relevance of the approach was illustrated with a real data set, where it is shown that, by removing the most influential observations, the decision about which model best fits the data is changed.

The generalized log-gamma mixture model with covariates: local influence and residual analysis

ORTEGA, Edwin M. M.; RIZZATO, Fernanda B.; DEMETRIO, Clarice G. B.
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.98%
In a sample of censored survival times, the presence of an immune proportion of individuals who are not subject to death, failure or relapse, may be indicated by a relatively high number of individuals with large censored survival times. In this paper the generalized log-gamma model is modified for the possibility that long-term survivors may be present in the data. The model attempts to separately estimate the effects of covariates on the surviving fraction, that is, the proportion of the population for which the event never occurs. The logistic function is used for the regression model of the surviving fraction. Inference for the model parameters is considered via maximum likelihood. Some influence methods, such as the local influence and total local influence of an individual are derived, analyzed and discussed. Finally, a data set from the medical area is analyzed under the log-gamma generalized mixture model. A residual analysis is performed in order to select an appropriate model.

Influence diagnostics for polyhazard models in the presence of covariates

FACHINI, Juliana B.; ORTEGA, Edwin M. M.; LOUZADA-NETO, Francisco
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.01%
In this paper, we present various diagnostic methods for polyhazard models. Polyhazard models are a flexible family for fitting lifetime data. Their main advantage over the single hazard models, such as the Weibull and the log-logistic models, is to include a large amount of nonmonotone hazard shapes, as bathtub and multimodal curves. Some influence methods, such as the local influence and total local influence of an individual are derived, analyzed and discussed. A discussion of the computation of the likelihood displacement as well as the normal curvature in the local influence method are presented. Finally, an example with real data is given for illustration.

The impact of life stage and societal culture on subordinate influence ethics: A study of Brazil, China, Germany, and the US

RALSTON, David A.; EGRI, Carolyn P.; CASADO, Tania; FU, Pingping; WANGENHEIM, Florian
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.02%
In this paper, we investigate the effects of societal values and life stage on subordinate influence ethics. Based on the evolving crossvergence theory of macro-level predictors of values evolution, we demonstrate the applicability of crossvergence theory in the micro-level context. Furthermore, our study provides the first empirical multi-level analysis of influence ethics utilizing a multi pie-country sample. Thus, we illustrate how the breath of crossvergence can be expanded to provide a multi-level theoretical foundation of values and behavior evolution across cultures. Specifically, we integrate micro-level life stage theory and macro-level societal culture theory to concurrently assess the contributions of each theory in explaining subordinate influence ethics across the diverse societies of Brazil. China, Germany and the U.S. Consistent with previous research, we found significant societal differences in influence ethics. However, we also found that life stage theory played a significant role in understanding influence ethics. Thus, our findings expand the crossvergence perspective on societal change, indicating that key micro-level predictors (e.g., life stage) should be included in cross-cultural research. (C) 2009 Elsevier Inc. All rights reserved.

Influence diagnostics in nonlinear mixed-effects elliptical models

RUSSO, Cibele M.; PAULA, Gilberto A.; AOKI, Reiko
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.01%
In this work we propose and analyze nonlinear elliptical models for longitudinal data, which represent an alternative to gaussian models in the cases of heavy tails, for instance. The elliptical distributions may help to control the influence of the observations in the parameter estimates by naturally attributing different weights for each case. We consider random effects to introduce the within-group correlation and work with the marginal model without requiring numerical integration. An iterative algorithm to obtain maximum likelihood estimates for the parameters is presented, as well as diagnostic results based on residual distances and local influence [Cook, D., 1986. Assessment of local influence. journal of the Royal Statistical Society - Series B 48 (2), 133-169; Cook D., 1987. Influence assessment. journal of Applied Statistics 14 (2),117-131; Escobar, L.A., Meeker, W.Q., 1992, Assessing influence in regression analysis with censored data, Biometrics 48, 507-528]. As numerical illustration, we apply the obtained results to a kinetics longitudinal data set presented in [Vonesh, E.F., Carter, R.L., 1992. Mixed-effects nonlinear regression for unbalanced repeated measures. Biometrics 48, 1-17], which was analyzed under the assumption of normality. (C) 2009 Elsevier B.V. All rights reserved.; FAPESP; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq...

Influence diagnostics in Birnbaum-Saunders nonlinear regression models

LEMONTE, Artur J.; PATRIOTA, Alexandre G.
Fonte: ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD Publicador: ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.04%
We consider the issue of assessing influence of observations in the class of Birnbaum-Saunders nonlinear regression models, which is useful in lifetime data analysis. Our results generalize those in Galea et al. [8] which are confined to Birnbaum-Saunders linear regression models. Some influence methods, such as the local influence, total local influence of an individual and generalized leverage are discussed. Additionally, the normal curvatures for studying local influence are derived under some perturbation schemes. We also give an application to a real fatigue data set.; FAPESP (Brazil); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental research on the influence of the air humidity conditions in an air conditioning system

Sobrinho, Pedro Magalhães; Tuna, Celso Eduardo
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 152-159
ENG
Relevância na Pesquisa
35.98%
The factors that have influence on the energy consumption of a small air conditioning system that are worth mentioning are the efficiencies of the compressor, evaporator and condenser, the form that the refrigerant flow is controlled, the fan model used, and climatic conditions. Within the climate issue, an interesting factor is that the relative humidity when it comes to the effect that it causes, especially in the performance of the air condenser, which generally is not considered in the projects. This study aims to evaluate the influence of humidity on the coefficient of system performance (COP), seeking to quantify their influence when it happens. The tests were performed on a testing bench, mounted at the Laboratory for Energy Efficiency (LAMOTRIZ) UNESP-Campus Guaratinguetá. In the study, the wet bulb temperature was ranged, keeping the rotation of the scroll compressor with application of a frequency inverter in its best performance. The test bench is provided with a supervisory system of data collection that is also able to control all functions of the bench. In the results, there was a significant influence, particularly when comparing high humidity conditions with low humidity, noting that only over 65% relative humidity is that significant changes are observed in the COP of the system. © 2013 Elsevier Inc.

Assessing influence in survival data with a cure fraction and covariates

ORTEGA, Edwin M. M.; CANCHO, Vicente G.; LACHOS, Victor Hugo
Fonte: INST ESTADISTICA CATALUNYA-IDESCAT Publicador: INST ESTADISTICA CATALUNYA-IDESCAT
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.98%
Diagnostic methods have been an important tool in regression analysis to detect anomalies, such as departures from error assumptions and the presence of outliers and influential observations with the fitted models. Assuming censored data, we considered a classical analysis and Bayesian analysis assuming no informative priors for the parameters of the model with a cure fraction. A Bayesian approach was considered by using Markov Chain Monte Carlo Methods with Metropolis-Hasting algorithms steps to obtain the posterior summaries of interest. Some influence methods, such as the local influence, total local influence of an individual, local influence on predictions and generalized leverage were derived, analyzed and discussed in survival data with a cure fraction and covariates. The relevance of the approach was illustrated with a real data set, where it is shown that, by removing the most influential observations, the decision about which model best fits the data is changed.

Methodology to control the influence of processing factors during composite stone fabrication

Lameiras,Fernando Soares; Silva,Glaucia Danielle Leirose da
Fonte: Escola de Minas Publicador: Escola de Minas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
Relevância na Pesquisa
35.98%
Composite stone is made of crushed materials bound by a polymer resin. A design of experimental techniques was used to evaluate the influence of factors (resin type, use of adhesion promoter, compaction pressure, vibration duration, use of a vacuum, and cure program) on the manufacturing of composite stone. The response variable was flexural strength. A 2IV6-2 fractional factorial design with five replications was initially used, which showed that resin type, use of adhesion promoter, and a cure program were factors of significant influence, as well as the interaction between them and the interaction between the resin type and the use of adhesion promoter. The data was re-arranged into a full 23 factorial design with ten replications to calculate the influence of these factors. The lack of influence of the other factors suggests that lower pressures should be used to improve the process by employing the surface response methodology.

Political Influence, Economic Interests and Endogenous Tax Structure in a Computable Equilibrium Framework: with Applicatioon to the United States, 1973 and 1983

HOTTE, Louis; WINER, Stanley L.
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Artigo de Revista Científica Formato: 48605 bytes; application/pdf
Relevância na Pesquisa
36.01%
A full understanding of public affairs requires the ability to distinguish between the policies that voters would like the government to adopt, and the influence that different voters or group of voters actually exert in the democratic process. We consider the properties of a computable equilibrium model of a competitive political economy in which the economic interests of groups of voters and their effective influence on equilibrium policy outcomes can be explicitly distinguished and computed. The model incorporates an amended version of the GEMTAP tax model, and is calibrated to data for the United States for 1973 and 1983. Emphasis is placed on how the aggregation of GEMTAP households into groups within which economic and political behaviour is assumed homogeneous affects the numerical representation of interests and influence for representative members of each group. Experiments with the model suggest that the changes in both interests and influence are important parts of the story behind the evolution of U.S. tax policy in the decade after 1973.; Si l’on aspire à une meilleure compréhension des choix publics, il est impératif de pouvoir faire la distinction entre les préférences de chaque électeur et l’influence qu’exerce chacun de ces électeurs...

Einfluss der Buckminsterfullerene auf Zellen des Immunsystems; The Influence of Buckminsterfullerenes on immunocompetent cells

Bunz, Hanno Friedemann Rüdiger
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
36.01%
Seit ihrer Entdeckung wecken Fullerene auf Grund ihrer chemischen Struktur große Hoffnungen. Zunehmend werden Fullerene besser verstanden und in der Medizin eingesetzt. Dabei können sie vielfältige Rollen einnehmen: Sei es als Transporter, als Verbindungsstück zwischen Medikament und Targeting-Protein, als Kontrastmittel oder als eigenständiges Medikament. Viele bisherige Studien schließen einen generell toxischen Effekt der Fullerene aus. Mehrere Studien beschreiben den Effekt von Fullerenen als Medikament oder als Kontrastmittel. Es gibt jedoch (außer den Zelltoxizitätsstudien) wenige Arbeiten, die sich mit der Interaktion dieser Stoffgruppe mit dem menschlichen Körper selbst beschäftigen. Für das Immunsystem gibt es nur vereinzelte Studien. Auf Grund der geringen Datenlage und der Erkenntnis, dass Fullerene Einfluss auf die angeborene Immunantwort zu haben scheinen, sowie der zunehmenden Anwendung im klinischen Sektor ist es von großer Wichtigkeit, den Einfluss der Fullerene auf den Körper und das Immunsystem besser zu verstehen. In diesem Kontext untersuchte die vorliegende Arbeit den Einfluss von zwei Vertretern der Fullerene (Polyhydroxy-C60 und N-ethyl-polyamin-C60) auf das Immunsystem. Dazu wurden die PBM Zellen aus dem Blut von 20 gesunden Probanden isoliert und kultiviert. In einem in-vitro Testsystem wurde der Einfluss der Fullerene auf diese Zellen getestet. Verschiedene Antigene (BCG...

The impact of prepersuasion and social influence tactics on military decision making

Greenlees, Andrew J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xiv, 73 p. : ill., map
Relevância na Pesquisa
36.07%
Approved for public release; distribution is unlimited.; Military decision making is influenced by a commander's perception of the physical environment. The information presented in the physical domain and how it is processed may be altered to persuade an adversary into making predetermined decisions. Prepersuasion social influence tactics may be used to structure a situation to establish a favorable climate for influence. Examples of how prepersuasion influence has impacted the military decision making process have been demonstrated in several international conflicts. One goal of prepersuasion influence is to have an adversary choose a predetermined course of action, on his own accord, that best suits the needs of the communicator. A second goal is to have an individual use prepersuasion to influence a large audience to support their decisions. Prepersuasion influence has been used effectively in the past because communicators, individuals or groups, have successfully impacted their audience's cognitive domain and shaped their perceptions. The ability to identify and resist the social influence tactics used to influence the military decision making process will benefit future commanders. What impact do prepersuasion influence tactics have on the military decision making process? This paper will answer this research question and offer recommendations on how military decision makers can resist prepersuasion influence.

Operational social influence in the Vietnam War an analysis of influence tactics used by the U.S. Marine's combined action program and the Viet Cong in South Vietnam

Pavlik, Thomas F.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xviii, 79 p. : ill.
Relevância na Pesquisa
36.07%
Approved for public release; distribution is unlimited.; Shortly after Marine forces landed in Vietnam in March, 1965, leaders in the field began experimenting with pacification/combined action. Although this concept went directly against the military strategy of the top leaders, which involved unlimited combat operations, four Combined Action Platoons were formed into a Combined Action Company in the summer of 1965. The Marine Corps Combined Action Program was viewed by many as one of the only successful pacification programs conducted in South Vietnam during the Vietnam War. The CAP concept in Vietnam combined a squad of Marines and a platoon of South Vietnamese Popular Forces to assist villages in resisting VC influence. By combining forces and living inside the villages, the Marines believed they could win the "hearts and minds" of the villagers. Although they may not have been aware that the science of social influence even existed, the Marines who were part of the CAP used several social influence tactics in their effort to gain the trust of the villagers and deny influence attempts from the VC. What they accomplished by chance should not be lost to history; it should be studied within the context of established social influence theory so future operations may benefit from their experience. This study views the Combined Action Program conducted by the U.S. Marines in South Vietnam through a lens of the science of social influence. A social influence analysis is conducted using cognitive Centers of Gravity and specific social influence tactics. The analysis results provide an insight into which social influence tactics can be applied during counterinsurgency operations.

Soft power and its impact on U.S. influence in Latin America

Cronin, Jason William
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: x, 85 p. ;
Relevância na Pesquisa
36.01%
Approved for public release; distribution in unlimited.; The role of Latin America in U.S. foreign policy has ebbed and flowed for over 100 years. Over the last 15 years, the relationship between the United States and Latin America has seen a precipitous drop in both cooperation and cordiality. The amicable relationships that the United States once enjoyed with Brazil and Venezuela specifically have become acrimonious. With the United States' increased interest in completing a Free Trade Area of the Americas agreement by January, relations with Brazil are vital. The United States' continued dependence on imported petroleum from Venezuela and America's concern over Venezuela's growing relationship with Cuba make this country also important to U.S. foreign policy. The thesis focuses on the United States' ability to use its cultural influence (soft power) to positively effect U.S. relations with Brazil and Venezuela. By analyzing past and present effects of U.S. cultural influence in these two countries, the U.S. can better understand and appreciate the influence it wields as the world's only remaining super power. This thesis finds that despite historic evidence, the U.S. has had and continues to have a propensity to use soft power influence tactically...

Influence : the new weapon in the battle for Southeast Asia

Manning, Richard W.R.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Formato: xii, 65 p. ; 28 cm.
Relevância na Pesquisa
36.01%
This thesis will provide a background look at China's recent history from World War II to present day to examine how they are gaining influence in the South Pacific and Southeast Asia. China is determined to become a global power and increase its international standing in term of influence and Southeast Asia is the start point. This thesis will also examine different approaches the United States and China use to gain Influence and resources. In particular, this thesis will use math modeling and game theory to explore linkages between assistance and Southeast Asian influence. This thesis examines how Chinese assistance is countering the U.S. efforts in Southeast Asia and why the United States must win the battle. This thesis will look at the current U.S. policies toward China and Southeast Asia and explore possible options for the United States in the future. Also how China may try to take control of the South China Sea. This thesis will make recommendations how the United States could more effectively utilize its resources to keep China in check. The thesis will conclude with recommendation for future policy based on the research to determine if the United States can win the battle for Southeast Asia using influence.; US Army (USA) author

Implicit Social Influence

Mason, Winter
Fonte: [Bloomington, Ind.] : Indiana University Publicador: [Bloomington, Ind.] : Indiana University
Tipo: Doctoral Dissertation
EN
Relevância na Pesquisa
36.07%
Thesis (PhD) - Indiana University, Psychology, 2007; Previous research has shown that people hold two kinds of attitudes, explicit attitudes, which are voluntary evaluations of things, and implicit attitudes, which are automatic evaluations that occur spontaneously and are difficult or impossible to control. Prior work has shown that social influence, whether it is intentional persuasion or incidental influence, usually leads the recipient of the influence to change his or her attitudes to be closer to the attitudes of the source of the influence. This work has focused on the effect of the explicit attitudes of the source of influence but ignored the possible effect of the source's implicit attitudes. Three studies examine the independent effect of the source's implicit attitude on a recipient in different social influence settings. In the first study, the implicit and explicit attitudes of a source towards a target were measured, and in the second two studies the implicit and explicit attitudes of the source were manipulated. In the first study, the recipient watched the source give a persuasive message about the target, in the second study the source described the target directly to the recipient, and in the third study, the recipient watched the source interacting with the target. Results revealed that implicit attitudes have an influence on a recipient...

How consumers persuade each other: rhetorical strategies of interpersonal influence in online communities

Scaraboto,Daiane; Rossi,Carlos Alberto Vargas; Costa,Diego
Fonte: ANPAD - Associação Nacional de Pós-Graduação e Pesquisa em Administração Publicador: ANPAD - Associação Nacional de Pós-Graduação e Pesquisa em Administração
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
Relevância na Pesquisa
36.01%
Persuasive messages are central to interpersonal influence in online communities, where consumers interact mainly through text. We employed a combination of netnography and computer-mediated discourse analysis to investigate how consumers exchange information related to products and brands in an online community. We identified a set of rhetorical strategies used by community members, including setting expectations, claiming expertise, prescribing, and celebrating acquiescence. Consumers employ these rhetorical strategies to influence each other's consumption decisions, report consumption decisions back to the community, and to gauge their influence on each other's choices. We compare this process to traditional types of interpersonal influence and discuss how our findings contribute to advancing the burgeoning literature on interpersonal influence in online contexts.

Influence maximization on families of graphs

Mouravski, Andrei
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
36.01%
We examine computing the maximum expected influence on paths and trees using the independent cascade model. We designed a polynomial time method for determining the expected influence from any initial state on the independent cascade model on acyclic influence graphs in O(|V(G)|² · max {|V(G)|,|V(E)|}) time. We designed a polynomial time program that would computes the maximum expected influence and optimal initially selected nodes on arbitrary paths in O(|V(T)|⁶/[epsilon]) on approximating the maximum expected influence on arbitrary trees with absolute error of at most ([epsilon] · 2|V(T)|).

Social network influence on romantic relationship commitment: do friends and family dictate our love lives?

Brummett, Erin
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
36.01%
Caplan, Scott; The purpose of this study was to assess the unique influences that different social network members have on individuals’ perceived social influence and ultimately their romantic relationship commitment. The research additionally sought to determine other predictors of the social network influence process including one’s disclosure to network members and one’s adult attachment style. Two hundred and eight undergraduate students in romantic relationships (n = 208) completed questionnaires measuring their frequency of disclosure, subjective norms, attachment style, and romantic commitment. Results indicated that participants were more motivated to comply with their parents than their friends and thus their subjective norms for their parents were more influential than those for their friend network members. The results also suggested that one’s attachment style, specifically avoidance, was a significant predictor of both disclosure and subjective norms. The model in the current study contributes to social network influence research by offering an examination of friends and parents as separate network members with distinct effects on individuals’ perceived social influence. Additionally, the model illustrates the effect of several predictors on both the social influence process and romantic commitment.; University of Delaware...

Percepção da influência no contexto do poder organizacional; Influence perception and power in organizations

Neiva, Elaine Rabelo; UnB - Brasília - DF; da Paz, Maria das Graça Torres; UnB - Brasília - DF
Fonte: Revista Psicologia: Organizações e Trabalho Publicador: Revista Psicologia: Organizações e Trabalho
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/01/2005 POR
Relevância na Pesquisa
36.07%
Este estudo considera a distinção entre poder organizacional e influência pessoal e apresenta como objetivos: 1) identificar as configurações de poder de duas organizações públicas; 2) verificar o quanto os indivíduos se percebem como usuários dos sistemas de influência organizacionais e o grau em que se percebem como influenciadores da unidade em que trabalham (autopercepção); 3) verificar o grau em que os indivíduos são percebidos como influenciadores da unidade em que trabalham (hetero-percepção); 4) estabelecer relações entre as variáveis anteriormente citadas e as variáveis demográficas. Foram aplicadas, a 202 funcionários de duas organizações, as escalas de Configuração de Poder Organizacional e de Autopercepção do uso dos sistemas de influência organizacionais e uma escala de Percepção de Influência no setor de trabalho. Os resultados retrataram que as organizações têm configurações semelhantes e que os sujeitos se consideraram exercendo mais influência do que realmente exercem de acordo com a percepção dos colegas.; There is a lack of clarity on the definitions of power and personal influence. Power and personal influence have been studied as separated phenomena in Social and Organizational Psychology...