Sample Kurtosis, GARCH-t and the Degrees of Freedom Issue

Econometric modeling based on the Student’s t distribution introduces an additional parameter — the degree of freedom. In this paper we use a simulation study to investigate the ability of (i) the GARCH-t model (Bollerslev, 1987) to estimate the true degree of freedom parameter and (ii) the sample kurtosis coefficient to accurately determine the implied degrees of freedom. Simulation results reveal that the GARCH-t model and the sample kurtosis coefficient provide biased and inconsistent estimates of the degree of freedom parameter. Moreover, by varying ó2, we find that only the constant term in the conditional variance equation is affected, while the other parameters remain unaffected.Student’s t distribution, Degree of freedom, Kurtosis coefficient, GARCH t model

Ambidexterity as practice : individual ambidexterity through paradoxical practices

Following the turn to practice in organization theory and the emerging interest in the microfoundations of ambidexterity, understanding the role of individuals in realizing ambidexterity approaches becomes crucial. Drawing insights from Greek philosophy on paradoxes, and practice theory on paradoxes and ambidexterity, we propose a view of individual ambidexterity grounded in paradoxical practices. Existing conceptualizations of ambidexterity are largely based on separation strategies. Contrary to this perspective, we argue that individual ambidexterity can be accomplished via paradoxical practices that renegotiate or transcend boundaries of exploration and exploitation. We identify three such paradoxical practices at the individual level that can advance understanding of ambidexterity: engaging in “hybrid tasks,” capitalizing cumulatively on previous learning, and adopting a mindset of seeking synergies between the competing demands of exploration and exploitation

Testing for Structural Breaks and other forms of Non-stationarity: a Misspecification Perspective

In the 1980s and 1990s the issue of non-stationarity in economic time series has been in the context of unit roots vs. mean trends in AR(p) models. More recently this perspective has been extended to include structural breaks. In this paper we take a much broader perspective by viewing the problem as one of misspecification testing: assessing the stationarity of the underlying process. The proposed misspecification testing procedure relies on resampling techniques to enhance the informational content of the observed data in an attempt to capture heterogeneity `locally' using rolling window estimators of the primary moments of the stochastic process. The effectiveness of the testing procedure is assessed using extensive Monte Carlo simulationsMaximum Entropy Bootstrap, Non-Stationarity

Cued Speech: A visual communication mode for the Deaf society

International audienceCued Speech is a visual mode of communication that uses handshapes and placements in combination with the mouth movements of speech to make the phonemes of a spoken language look different from each other and clearly understandable to deaf individuals. The aim of Cued Speech is to overcome the problems of lip reading and thus enable deaf persons to wholly understand spoken language. In this study, automatic phoneme recognition in Cued Speech for French based on hidden Markov model (HMMs) is introduced. The phoneme correct for a normal-hearing cuer was 82.9%, and for a deaf 81.5%. The results also showed, that creating cuer-independent HMMs should not face any specific difficulties, other than those occured in audio speech recognition

Organization change failure, deep structures and temporality : appreciating Wonderland

Organization change failure has typically been viewed as occurring when expected outcomes of change have not been met. This view downplays key, but frequently hidden organizational dimensions such as deep structures and temporality. In this paper, drawing inspiration from the story of Alice in Wonderland (Carroll, 2011), we distinguish between surface level intervention approaches to change, deeper process approaches and, deeper yet structuration approaches and suggest the different ways they approach change failure as well as the implications of these. On the basis of our exploration we propose a three-fold way forward: adopting a process-based, empirically grounded and reflective approach to understanding change and its often-failed outcomes; adopting methodologies that can capture deep structures and temporal dimensions; and incorporating expanded conceptions of time as a multi-level, nested construct. We illustrate our ideas of deep structures and temporality by drawing from a particularly important illustration of long term successful change that includes multiple short term failures, that of the National Aeronautics and Space Administration in the United States (NASA)

No lost generation: refugee children education in Cyprus

Education is a right for every child and a critical opportunity. For refugee children and adolescents, it holds the key to a life with less poverty, better health and an increased ability to take the future into their own hands. This research paper aims to investigate the current situation in Cyprus in regard to the integration of refugee children in the educational system and suggest strategies and policies that will have an impact on the educational chances of these children. It combines data from desk research, interviews with key actors and educators, as well as interviews with refugee children and parents. Findings address the main barriers to integration in the educational system for refugee children and provide the background for recommendations to be made that will increase the educational success of these children

Cued Speech Automatic Recognition in Normal Hearing and Deaf Subjects

International audienceThis article discusses the automatic recognition of Cued Speech in French based on hidden Markov models (HMMs)

In pursuit of ambidexterity : managerial reactions to innovation-efficiency tensions

Whereas tensions arising from the pursuit of ambidexterity have been documented, how these are interpreted and managed by actors themselves remains largely unexplored. Based on in-depth case research in a large Scandinavian based telecommunications organization pursuing ambidexterity, we identify a path-dependent process of tension interpretation and tension management at different levels of the organization. Our findings suggest that in the context of an ambidextrous strategy, actors are actively involved in managing arising tensions based on their differing interpretations of these tensions (where ambidextrous demands are seen as complementary, conflicting or interrelated). We find that these interpretations are influenced by actors’ strategic orientation and organizational level. Our study extends understanding of the pursuit of ambidexterity in practice, offering a pluralist, path-dependent perspective of how actors perceive and deal with ambidexterity tensions

How do innovators stay innovative? A longitudinal case analysis

Purpose – How can some companies be the innovation leader in their industry over prolonged periods of time, while others cannot? The purpose of this study is to understand a firm’s capability to be a successful serial innovator and to generate a constant stream of industry-leading innovations. Design/Methodology/Approach – The paper uses a longitudinal case study approach to gain an understanding of what and how Singapore Airlines (SIA) sustained service innovation for over 30 years. The study uses triangulation, whereby the core data from in-depth interviews with senior and middle management, and frontline employees were complemented with academic research, case studies, annual reports, observations, and archival documents. 240 single-spaced pages of interview transcripts with over 130,000 words were analyzed and coded using MAXQDA for identifying repeated patterns of meaning. Findings – We identified three key institutional foundations for service innovation: (1) innovation climate (i.e., leadership and service culture), (2) human capital (i.e., recruitment, training and development, and engagement and incentives), and (3) resource configurations (i.e., systems, structure, and processes). These foundations enabled the organization to build the following four service innovation-related dynamic capabilities: (1) embrace ambidexterity, (2) institutionalize learning and knowledge integration, (3) orchestrate collaboration, and (4) reinvent customer value. Interestingly, these institutional foundations and capabilities remained largely stable across 30 years; what changed were the contexts and specifics, not the foundations and capabilities. Research Limitations and Implications – Data were collected only from one company. Due to the method of thematic analysis the generalizability of our findings needs further investigation. Originality/ValueOriginality/Value – This study is the first to investigate the drivers of industry-leading sustained service innovation over a prolonged period of time. The proposed framework provides a fuller and more integrated picture of sustained service innovation than past cross-sectional studies