Models of atypical development must also be models of normal development

Functional magnetic resonance imaging studies of developmental disorders and normal cognition that include children are becoming increasingly common and represent part of a newly expanding field of developmental cognitive neuroscience. These studies have illustrated the importance of the process of development in understanding brain mechanisms underlying cognition and including children ill the study of the etiology of developmental disorders

Are developmental disorders like cases of adult brain damage? Implications from connectionist modelling

It is often assumed that similar domain-specific behavioural impairments found in cases of adult brain damage and developmental disorders correspond to similar underlying causes, and can serve as convergent evidence for the modular structure of the normal adult cognitive system. We argue that this correspondence is contingent on an unsupported assumption that atypical development can produce selective deficits while the rest of the system develops normally (Residual Normality), and that this assumption tends to bias data collection in the field. Based on a review of connectionist models of acquired and developmental disorders in the domains of reading and past tense, as well as on new simulations, we explore the computational viability of Residual Normality and the potential role of development in producing behavioural deficits. Simulations demonstrate that damage to a developmental model can produce very different effects depending on whether it occurs prior to or following the training process. Because developmental disorders typically involve damage prior to learning, we conclude that the developmental process is a key component of the explanation of endstate impairments in such disorders. Further simulations demonstrate that in simple connectionist learning systems, the assumption of Residual Normality is undermined by processes of compensation or alteration elsewhere in the system. We outline the precise computational conditions required for Residual Normality to hold in development, and suggest that in many cases it is an unlikely hypothesis. We conclude that in developmental disorders, inferences from behavioural deficits to underlying structure crucially depend on developmental conditions, and that the process of ontogenetic development cannot be ignored in constructing models of developmental disorders

Cargo Logistics Airlift Systems Study (CLASS). Volume 3: Cross impact between the 1990 market and the air physical distribution systems, book 1

The interrelations between the infrastructure and the forecast future market are discussed. Also, using forecasts of market growth for a base, future aircraft and air service concepts were evaluated

Nonmodularity index for capacity identifying with multiple criteria preference information

Nonmodularity is a more general concept than nonadditivity which provides a more inclusive reflection of the relationship between subsets of criteria in multicriteria decision making. In this paper, we construct the nonmodularity index to describe the kind and intensity of interaction within a subset of criteria associated with the nonmodularity, and introduce the total nonmodularity and nonadditivity (amount) index to reflect the interactions within a capacity as a whole. We prove some fundamental properties of the nonmodularity index, develop its expression in Möbius representation and prove that both nonmodularity and nonadditivity indices can serve as alternative representations of a capacity in terms of matrix form. We also discuss in detail the explicit reciprocal transform representations of the nonmodularity index, as well as the nonadditivity index with the capacity and the Möbius representation. In view of these explicit interaction indices and their intuitive merits, we develop specialized capacity identification methods in terms of nonmodularity and nonadditivity indices and formulate the corresponding linear programming problems to represent and aggregate the decision makers’ preference information. © 201

Auditory processing in patients with structural lesions of the brain.

This thesis investigated structure versus function in the central auditory nervous system (CANS) by using the lesion study approach and by utilising a validated clinical test battery for the assessment of auditory processing as well as self- or parent report measures. The central auditory test results were correlated with the macroscopical appearance of the CANS on brain MRI and with patient reported hearing difficulties. The two regions of interest for this study were the insula (first group of studies) and the interhemispheric pathway, comprised by the corpus callosum and the anterior commissure (second group of studies). First group of studies: Patients with a history of ischemic or haemorrhagic cerebral stroke of the CANS were identified by their scans. Exclusion criteria were significant psychiatric or expressive language disorders. Second group of studies: Adults and children with congenital aniridia and abnormality of the interhemispheric pathway due to a PAX6 mutation were recruited. The assessment included questionnaire of auditory capabilities, baseline audiometry (pure tone audiometry, tympanometry and otoacoustic emissions) and central auditory tests (speech and non-speech). The brain MRIs of these patients were visually inspected (1st and 2nd group of studies). The corpus callosum area was measured in the children participants of the 2nd group of studies

Socio-cognitive analysis of engineering systems design : shared knowledge, process, and product

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 213-222).This research is based on the well-known but seldom stated premise that the design of complex engineered systems is done by people -- each with their own knowledge, thoughts, and views about the system being designed. To understand the implications of this social dimension, the Integrated Concurrent Engineering (ICE) environment, a real-world setting for conceptual space mission design, is examined from technical and social perspectives. An integrated analysis demonstrates a relationship among shared knowledge, process, and product. The design process is analyzed using a parameter-based Design Structure Matrix (DSM). This model, consisting of 682 dependencies among 172 parameters, is partitioned (reordered) to reveal a tightly coupled design process. Further analysis shows that making starting assumptions about design budgets leads to a straightforward process of well-defined and sequentially executed design iterations. To analyze the social aspects, a network-based model of shared knowledge is proposed. By quantifying team members' common views of design drivers, a network of shared mental models is built to reveal the structure of shared knowledge at a snapshot in time. A structural comparison of pre-session and post-session networks is used to compute a metric of change in shared knowledge. Based on survey data from 12 design sessions, a correlation is found between change in shared knowledge and each of several system attributes, including technological maturity, development time, mass, and cost. Integrated analysis of design process and shared knowledge yields three interdisciplinary insights.(cont.) First, certain features of the system serve a central role both in the design process and in the development of shared knowledge. Second, change in shared knowledge is related to the design product. Finally, change in shared knowledge and team coordination (agreement between expected and reported interactions) are positively correlated. The thesis contributes to the literature on product development, human factors engineering, and organizational and social psychology. It proposes a rigorous means of incorporating the socio cognitive aspects of design into the practice of systems engineering. Finally, the thesis offers a set of recommendations for the formation and management of ICE design facilities and discusses the applicability of the proposed methodology to the full-scale development of complex engineered systems.by Mark Sean Avnet.Ph.D