561 resultados para Predictability
Resumo:
Artifact selection decisions typically involve the selection of one from a number of possible/candidate options (decision alternatives). In order to support such decisions, it is important to identify and recognize relevant key issues of problem solving and decision making (Albers, 1996; Harris, 1998a, 1998b; Jacobs & Holten, 1995; Loch & Conger, 1996; Rumble, 1991; Sauter, 1999; Simon, 1986). Sauter classifies four problem solving/decision making styles: (1) left-brain style, (2) right-brain style, (3) accommodating, and (4) integrated (Sauter, 1999). The left-brain style employs analytical and quantitative techniques and relies on rational and logical reasoning. In an effort to achieve predictability and minimize uncertainty, problems are explicitly defined, solution methods are determined, orderly information searches are conducted, and analysis is increasingly refined. Left-brain style decision making works best when it is possible to predict/control, measure, and quantify all relevant variables, and when information is complete. In direct contrast, right-brain style decision making is based on intuitive techniques—it places more emphasis on feelings than facts. Accommodating decision makers use their non-dominant style when they realize that it will work best in a given situation. Lastly, integrated style decision makers are able to combine the left- and right-brain styles—they use analytical processes to filter information and intuition to contend with uncertainty and complexity.
Resumo:
Online communities are prime sources of information. The Web is rich with forums and Question Answering (Q&A) communities where people go to seek answers to all kinds of questions. Most systems employ manual answer-rating procedures to encourage people to provide quality answers and to help users locate the best answers in a given thread. However, in the datasets we collected from three online communities, we found that half their threads lacked best answer markings. This stresses the need for methods to assess the quality of available answers to: 1) provide automated ratings to fill in for, or support, manually assigned ones, and; 2) to assist users when browsing such answers by filtering in potential best answers. In this paper, we collected data from three online communities and converted it to RDF based on the SIOC ontology. We then explored an approach for predicting best answers using a combination of content, user, and thread features. We show how the influence of such features on predicting best answers differs across communities. Further we demonstrate how certain features unique to some of our community systems can boost predictability of best answers.
Resumo:
Detection and interpretation of adverse signals during preclinical and clinical stages of drug development inform the benefit-risk assessment that determines suitability for use in real-world situations. This review considers some recent signals associated with diabetes therapies, illustrating the difficulties in ascribing causality and evaluating absolute risk, predictability, prevention, and containment. Individual clinical trials are necessarily restricted for patient selection, number, and duration; they can introduce allocation and ascertainment bias and they often rely on biomarkers to estimate long-term clinical outcomes. In diabetes, the risk perspective is inevitably confounded by emergent comorbid conditions and potential interactions that limit therapeutic choice, hence the need for new therapies and better use of existing therapies to address the consequences of protracted glucotoxicity. However, for some therapies, the adverse effects may take several years to emerge, and it is evident that faint initial signals under trial conditions cannot be expected to foretell all eventualities. Thus, as information and experience accumulate with time, it should be accepted that benefit-risk deliberations will be refined, and adjustments to prescribing indications may become appropriate. © 2013 by the American Diabetes Association.
Resumo:
Artifact selection decisions typically involve the selection of one from a number of possible/candidate options (decision alternatives). In order to support such decisions, it is important to identify and recognize relevant key issues of problem solving and decision making (Albers, 1996; Harris, 1998a, 1998b; Jacobs & Holten, 1995; Loch & Conger, 1996; Rumble, 1991; Sauter, 1999; Simon, 1986). Sauter classifies four problem solving/decision making styles: (1) left-brain style, (2) right-brain style, (3) accommodating, and (4) integrated (Sauter, 1999). The left-brain style employs analytical and quantitative techniques and relies on rational and logical reasoning. In an effort to achieve predictability and minimize uncertainty, problems are explicitly defined, solution methods are determined, orderly information searches are conducted, and analysis is increasingly refined. Left-brain style decision making works best when it is possible to predict/control, measure, and quantify all relevant variables, and when information is complete. In direct contrast, right-brain style decision making is based on intuitive techniques—it places more emphasis on feelings than facts. Accommodating decision makers use their non-dominant style when they realize that it will work best in a given situation. Lastly, integrated style decision makers are able to combine the left- and right-brain styles—they use analytical processes to filter information and intuition to contend with uncertainty and complexity.
Resumo:
Everyday human behaviour relies on our ability to predict outcomes on the basis of moment by moment information. Long-range neural phase synchronization has been hypothesized as a mechanism by which ‘predictions’ can exert an effect on the processing of incoming sensory events. Using magnetoencephalography (MEG) we have studied the relationship between the modulation of phase synchronization in a cerebral network of areas involved in visual target processing and the predictability of target occurrence. Our results reveal a striking increase in the modulation of phase synchronization associated with an increased probability of target occurrence. These observations are consistent with the hypothesis that long-range phase synchronization plays a critical functional role in humans' ability to effectively employ predictive heuristics.
Resumo:
Motivation: The immunogenicity of peptides depends on their ability to bind to MHC molecules. MHC binding affinity prediction methods can save significant amounts of experimental work. The class II MHC binding site is open at both ends, making epitope prediction difficult because of the multiple binding ability of long peptides. Results: An iterative self-consistent partial least squares (PLS)-based additive method was applied to a set of 66 pep- tides no longer than 16 amino acids, binding to DRB1*0401. A regression equation containing the quantitative contributions of the amino acids at each of the nine positions was generated. Its predictability was tested using two external test sets which gave r pred =0.593 and r pred=0.655, respectively. Furthermore, it was benchmarked using 25 known T-cell epitopes restricted by DRB1*0401 and we compared our results with four other online predictive methods. The additive method showed the best result finding 24 of the 25 T-cell epitopes. Availability: Peptides used in the study are available from http://www.jenner.ac.uk/JenPep. The PLS method is available commercially in the SYBYL molecular modelling software package. The final model for affinity prediction of peptides binding to DRB1*0401 molecule is available at http://www.jenner.ac.uk/MHCPred. Models developed for DRB1*0101 and DRB1*0701 also are available in MHC- Pred
Resumo:
Although people and events that disconfirm observers' expectancies can increase their creativity, sometimes such social schema violations increase observers' rigidity of thought and undermine creative cognition. Here we examined whether individual differences in the extent to which people prefer structure and predictability determine whether social schema violations facilitate or hamper creativity. Participants in Study 1 formed impressions of a schema-inconsistent female mechanic (vs. a schema-consistent male mechanic). Following schema-inconsistent rather than -consistent information, participants low (high) in need for structure showed better (impeded) creative performance. Participants in Study 2 memorized a series of images in which individuals were placed on a schema-inconsistent (vs. consistent) background (e.g., an Eskimo on the desert vs. on a snowy landscape). Following schema-inconsistent imagery, participants low (high) in need for structure increased (decreased) divergent thinking. © 2014 by the Society for Personality and Social Psychology, Inc.
Resumo:
This chapter explores ways in which rigorous mathematical techniques, termed formal methods, can be employed to improve the predictability and dependability of autonomic computing. Model checking, formal specification, and quantitative verification are presented in the contexts of conflict detection in autonomic computing policies, and of implementation of goal and utility-function policies in autonomic IT systems, respectively. Each of these techniques is illustrated using a detailed case study, and analysed to establish its merits and limitations. The analysis is then used as a basis for discussing the challenges and opportunities of this endeavour to transition the development of autonomic IT systems from the current practice of using ad-hoc methods and heuristic towards a more principled approach. © 2012, IGI Global.
Resumo:
I examine the predictability of dividend cuts based on the time interval between dividend announcement dates using a large dataset of US firms from 1971 to 2014. The longer the time interval between dividend announcements, the larger the probability of a cut in the dividend per share, consistent with the view that firms delay the release of bad news.
Resumo:
The primary research question was: What is the nature and degree of alignment between the tenets of learning organizations and the policies and practices of a community college concerning adjunct instructors? I investigated the employment experiences of 8 adjunct instructors at a large community college in the Southeastern U.S. to (a) describe and explain the perspectives of the adjuncts, (b) describe and explain my own adjunct employment experience at the same college, (c) determine how the adjunct policies and practices collectively encountered were congruent with or at variance with the tenets of learning organizations, and (d) to use this framework to support recommendations that may help the college achieve more favorable alignment with these tenets. ^ Data on perceived adjunct policies and practices were reduced into 11 categories and, using matrices, were compared with 5 major categories of learning organization tenets. The 5 categories of tenets were: (a) inputs, (b) information flow/communication, (c) employee inclusion/value, (d) teamwork, and (e) facilitation of change. The 11 categories of the college's policies and practices were (a) becoming an adjunct, (b) full-time employment aspirations, (c) salary, (d) benefits, (e) job security and predictability, (f) job satisfaction, (g) respect, (h) support services, (i) professional development, (j) institutional inclusion, and (k) future role of adjuncts. The reflective journal component relied on a 5-year (1995–2000) personal and professional journal maintained by me during employment with the same college as the participants. ^ Findings indicate that the college's adjunct policies and practices were most incongruent with 25 of the 70 learning organization tenets. These incongruencies spanned the 5 categories, although most occurred in the Employee/Inclusion/Value category. Adjunct instructors wanted inclusion, respect, value, trust, and empowerment in decision making processes that affect adjunct policies and practices of the college, but did not perceive this to be a part of the present situation. ^
Resumo:
This dissertation addressed two broad problems in international macroeconomics and conflict analysis. The first problem in the first chapter looked at the behavior of exchange rate and its interaction with industry-level tradable goods prices for three countries, USA, UK and Japan. This question has important monetary policy implications. Here, I computed to what extent changes in exchange rate affected prices of consumer, producer, and export goods. I also studied the timing of these changes in these prices. My results, based on thirty-four industrial prices for USA, UK and Japan, supported the view that changes in exchange rates significantly affect prices of industrial and consumer goods. It also provided an insight to the underlying economic process that led to changes in relative prices. ^ In the second chapter, I explored the predictability of future inflation by incorporating shocks to exchange rates and clearly specified the transmission mechanisms that link exchange rates to industry-level consumer and producer prices. Employing a variety of linear and state-of-the-art nonlinear models, I also predicted growth rates of future prices. Comparing levels of inflation obtained from the above approaches showed superiority of the structural model incorporating the exchange rate pass-through effect. ^ The second broad issue addressed in the third chapter of the dissertation investigated the economic motives for conflict, manifested by rebellion and civil war for seventeen Latin American countries. Based on the analytical framework of Garfinkel, Skaperdas and Syropoulos (2004), I employed ordinal regressions and Markov switching for a panel of seventeen countries to identify trade and openness factors responsible for conflict occurrence and intensity. The results suggested that increased trade openness reduced high intensity domestic conflicts but overdependence on agricultural exports, along with a lack of income earning opportunities lead to more conflicts. Thereafter, using the Cox Proportional Hazard model I studied “conflict duration” and found that over-reliance on agricultural exports explained a major part of the length of conflicts in addition to various socio-political factors. ^
Resumo:
To help lawyers uncover jurors' attitudes and predict verdict, litigation experts recommend that attorneys encourage jurors to repeatedly express their attitudes during voir dire. While social cognitive literature has established that repeated expression of attitudes increases accessibility and behavior predictability, the persuasive twist on the method exercised in trials deserves empirical investigation. Only one study has examined the use of repeated expression within a legal context with the results finding that the tactic increased accessibility, but did not influence the attitude verdict relationship. This dissertation reexamines the ability of civil attitudes to predict verdict in a civil trial and investigates the use of repeated expression as a persuasive tactic utilized by both parties (Plaintiff and Defense) within a civil voir dire in an attempt to increase attitudinal strength, via accessibility, and change attitudes to better predict verdict. This project also explores potential moderators, repetition by the opposing party and the use of a forewarning, to determine their ability to counter the effects of repeated expression on attitudes and verdict.^ This dissertation project asked subjects to take on the role of jurors in a civil case. During the voir dire questioning session, the number of times the participants were solicited to express their attitudes towards litigation crisis by both parties was manipulated (one vs. five). Also manipulated was the inclusion of a forewarning statement from the plaintiff, within which mock jurors were cautioned about the repeated tactics that the defense may use to influence their attitudes. Subsequently, participants engaged in a response latency task which measured the accessibility of their attitudes towards various case-related issues. After reading a vignette of a fictitious personal injury case, participants rendered verdict decisions and responded to an attitude evaluation scale. Exploratory factor analyses, Probit regressions, and path analyses were used to analyze the data. Results indicated that the act of repeated expression influenced both the accessibility and value of litigation crisis attitudes thus increasing the attitude-verdict relationship, but only when only one party engaged in it. Furthermore, the forewarning manipulation did moderate the effect of repeated expression on attitude change and verdict, supporting our hypothesis.^
Resumo:
A challenge facing nutrition care providers and the Chinese community is how to improve and maintain dietary adequacy (DA) and quality of life (QoL) in older Chinese Americans. Little is known about the factors contributing to DA and the relationships between DA and QoL among community-dwelling older Chinese adults in South Florida. A DA model and a QoL model were hypothesized. ^ Structured interviews with 100 Chinese Floridians, ages ≥60, provided data to test the hypothesized models, using structured equation modeling. Participants (mean age ± SD = 70.9 + 6.8 years) included 59% females, 98% foreign-born, 23% non-English speakers, and 68% residents of Florida for 20 years or more. The findings supported the study hypotheses: an excellent goodness-of-fit of the DA model (χ2/DF (7) = .286; CFI = 1.000; TLI = 1.704; NFI = .934; RMSEA < .001, 90% CI < .0001 to < .001; SRMR = .033; AIC = 30.000; and BIC = 66.472) and an excellent goodness-of-fit of the QoL model (χ2/DF (6) = .811; CFI = 1.000; TLI = 1.013; NFI = .979; RMSEA < .001, 90% CI < .001 to .116; SRMR = .0429; AIC = 34.869; and BIC = 73.946). ^ The DA model consisted of a structure of four indicators (i.e. Body Mass Index, food practices, diet satisfaction, and appetite) and one intervening variable (i.e. combining nutrient adequacy with nutritional risk). BMI was the strongest, most reliable indicator of DA with the highest predictability coefficient (.63) and the ability to differentiate between participants with different DA levels. The QoL model consisted of a two-dimensional construct with one indicator (i.e. physical function) and one intervening variable (i.e. combining loneliness with social resources, depression, social function, and mental health). Physical function had the strongest predictability coefficient (.89), while other indicators contributed to QoL indirectly. When integrating the DA model to the QoL model, DA appears to influence QoL via indirect pathways. ^ It is necessary to include a precise measure of BMI as the basis for assessing DA in this population. Important goals of dietary interventions should be improving physical function and alleviating social and emotional isolation. ^
Resumo:
After the end of the Cold War, democratization and good governance became the organizing concepts for activities of the United Nations, regional organizations and states in the fields of peace, development and security. How can this increasing interest in democratization and its connection with international security be explained? This dissertation applies the theoretical tools developed by Michel Foucault in his discussions of disciplinarity and government to the analysis of the United Nations debate on democracy in the 1990s, and of two United Nations pro-democracy peacekeeping operations and their aftermath: the United Nations interventions in Haiti and Croatia. It probes “how” certain techniques of power came into being and describes their effects, using as data the texts that elaborate the United Nations understanding of democracy and the texts that constitute peacekeeping. ^ In the face of the proliferation of unpredictable threats in the last decades of the twentieth century a new form of international power emerged. Order in the international arena increasingly was maintained through activities aimed at reducing risk and increasing predictability through the normalization of “rogue” states. The dissertation shows that in the context of these activities, which included but were not limited to UN peacekeeping, normality was identified with democracy, non-democratic regimes with international threats, and democratization with international security. “Good governance” doctrines translated the political debate on democracy into the technical language of functioning state institutions. International organizations adopted good governance as the framework that made democratization a universal task within the reach of their expertise. In Haiti, the United Nations engaged in efforts to transform punishment institutions (the judiciary, police and the prison) into disciplined and disciplinary machines. In Croatia, agreements signed in the context of peacekeeping established in detail the rules of functioning of administrations and the monitoring mechanisms for their implementation. However, in Haiti, the institutions promoted were not sustainable. And in Croatia reforms are stalled by lack of consensus. ^ This dissertation puts efforts to bring about democracy through peacekeeping in the context of a specific modality of power and suggests caution in engaging in universal normalizing endeavors. ^
Resumo:
Hydrophobicity as measured by Log P is an important molecular property related to toxicity and carcinogenicity. With increasing public health concerns for the effects of Disinfection By-Products (DBPs), there are considerable benefits in developing Quantitative Structure and Activity Relationship (QSAR) models capable of accurately predicting Log P. In this research, Log P values of 173 DBP compounds in 6 functional classes were used to develop QSAR models, by applying 3 molecular descriptors, namely, Energy of the Lowest Unoccupied Molecular Orbital (ELUMO), Number of Chlorine (NCl) and Number of Carbon (NC) by Multiple Linear Regression (MLR) analysis. The QSAR models developed were validated based on the Organization for Economic Co-operation and Development (OECD) principles. The model Applicability Domain (AD) and mechanistic interpretation were explored. Considering the very complex nature of DBPs, the established QSAR models performed very well with respect to goodness-of-fit, robustness and predictability. The predicted values of Log P of DBPs by the QSAR models were found to be significant with a correlation coefficient R2 from 81% to 98%. The Leverage Approach by Williams Plot was applied to detect and remove outliers, consequently increasing R 2 by approximately 2% to 13% for different DBP classes. The developed QSAR models were statistically validated for their predictive power by the Leave-One-Out (LOO) and Leave-Many-Out (LMO) cross validation methods. Finally, Monte Carlo simulation was used to assess the variations and inherent uncertainties in the QSAR models of Log P and determine the most influential parameters in connection with Log P prediction. The developed QSAR models in this dissertation will have a broad applicability domain because the research data set covered six out of eight common DBP classes, including halogenated alkane, halogenated alkene, halogenated aromatic, halogenated aldehyde, halogenated ketone, and halogenated carboxylic acid, which have been brought to the attention of regulatory agencies in recent years. Furthermore, the QSAR models are suitable to be used for prediction of similar DBP compounds within the same applicability domain. The selection and integration of various methodologies developed in this research may also benefit future research in similar fields.