235 research outputs found
The Development and Validation of a Sentence-Completion Method: a Semi-Structured Projective Technique Designed for Personality Study
Problem. There are very few objective instruments available for use in the psychological diagnosis of emotional impairment at the elementary-school level. The determination of emotional impairment has often been based on clinical judgment and subjectivity. In addition, psychological instruments have been attacked from the standpoint of reliability and validity. Major concerns relate to the seriousness of misclassification and the limited success-rate of rehabilitation efforts. The sentence-completion method is popularly used by clinicians. However, the available incomplete-sentence blanks used at the elementary-school level rely almost entirely on face validity. Public Legislation 94-142 and the Rehabilitation Act of 1973 specifically require that psychological instruments be validated for the purposes for which they are used. Therefore the purpose of this investigation was to develop and validate an objective sentence-completion method. The ability of theinstrument to discriminate among special education groups, the sensitivity of theinstrument to long-term treatment effects, and the consistency of scores produced by school psychologists using the objective scoring device were the important factors analyzed.
Method. Based on a review of the previous research done on this method of personality study, an initial list of sentence-completion stems was developed. A more refined list ofstems was developed through two field tests using the Chi-square method of analysis to determine which stems exhibited a tendency to discriminate between the emotionally impaired and regular-education youngsters. Feedback from test administrators pertaining to language comprehension difficulty, as well as analysis for disproportionate numbers ofresponses were also useful guides to final stem selection. The final form consisted oftwenty stems. A personality adjustment scale of Negative, Denial, Neutral, Acceptance, and Positive was devised and the quantitative values 1,2,3,4, and 5, respectively, were assigned. The final administration to determine the ability of the instrument to segregate groups was conducted on emotionally impaired, educable mentally impaired, learning impaired, and regular-education youngsters and analyzed by a nonparametric sign test of differences between medians. Tests of inter-scorer reliability using school psychologists trained on thescoring system were conducted. In addition, the changes in performance on the instrument were compared to personality-adjustment changes over a one-year period as evaluated by an experienced teacher of the emotionally impaired.
Results. Inner-city special-education groups were placed on the Personality Adjustment Continuum in the order: emotionally impaired--2.3, educable mentally impaired--2.6, learning impaired--2.7, regular education--3.2. A statistically significant difference in performance on the instrument was seen between all special-education groups and regular-education youngsters (p \u3c .05). Six correlation coefficients of inter-scorer reliability, ranging from .96 to 1.00, were obtained by school psychologists using the scoring device, suggesting that theinstrument can be scored with relatively high consistency. The instrument was able to measure significant (t = 5.08, dt = 7, p \u3c .05), long-term, personality-adjustment changes which correctly corresponded to teacher evaluation.
Conclusion. The instrument produced responds to personality-adjustment changes and can be consistently scored. The instrument was able to distinguish special-education from regular-education pupils. However, special-education youngsters in this population appear to be similar in emotional status even though they are statistically significantly different from regular-education youngsters. The Bacchus Sentence-Completion Method, produced from this investigation, represents a major tool that can be used in the non-biased assessment of emotional impairment at the elementary-school level
The role of the agent's outside options in principal-agent relationships
We consider a principal-agent model of adverse selection where, in order to trade with the principal,
the agent must undertake a relationship-specific investment which affects his outside option to trade,
i.e. the payoff that he can obtain by trading with an alternative principal. This creates a distinction
between the agentâs ex ante (before investment) and ex post (after investment) outside options to trade.
We investigate the consequences of this distinction, and show that whenever an agentâs ex ante and ex
post outside options differ, this may equip the principal with an additional tool for screening among
different agent types, by randomizing over the probability with which trade occurs once the agent
has undertaken the investment. In turn, this may enhance the efficiency of the optimal second-best
contract
Researching domestic violence and abuse in healthcare settings: challenges and issues
Domestic violence and abuse (DVA) is now recognised as a significant global health and societal issue. Conducting DVA research in healthcare contexts requires the consideration and understanding of a number of practical, methodological and ethical issues. Based on their experiences of working as clinicians and researchers, the authors aim to explore some of the pertinent issues and challenges associated with DVA research conducted in healthcare settings involving patients and/or healthcare professionals or both. A number of ethical, methodological and practical challenges, particularly those associated with research design and data collection, and ethical challenges related to participants and researchers, are explored
Randomisation and Derandomisation in Descriptive Complexity Theory
We study probabilistic complexity classes and questions of derandomisation
from a logical point of view. For each logic L we introduce a new logic BPL,
bounded error probabilistic L, which is defined from L in a similar way as the
complexity class BPP, bounded error probabilistic polynomial time, is defined
from PTIME. Our main focus lies on questions of derandomisation, and we prove
that there is a query which is definable in BPFO, the probabilistic version of
first-order logic, but not in Cinf, finite variable infinitary logic with
counting. This implies that many of the standard logics of finite model theory,
like transitive closure logic and fixed-point logic, both with and without
counting, cannot be derandomised. Similarly, we present a query on ordered
structures which is definable in BPFO but not in monadic second-order logic,
and a query on additive structures which is definable in BPFO but not in FO.
The latter of these queries shows that certain uniform variants of AC0
(bounded-depth polynomial sized circuits) cannot be derandomised. These results
are in contrast to the general belief that most standard complexity classes can
be derandomised. Finally, we note that BPIFP+C, the probabilistic version of
fixed-point logic with counting, captures the complexity class BPP, even on
unordered structures
On QBF Proofs and Preprocessing
QBFs (quantified boolean formulas), which are a superset of propositional
formulas, provide a canonical representation for PSPACE problems. To overcome
the inherent complexity of QBF, significant effort has been invested in
developing QBF solvers as well as the underlying proof systems. At the same
time, formula preprocessing is crucial for the application of QBF solvers. This
paper focuses on a missing link in currently-available technology: How to
obtain a certificate (e.g. proof) for a formula that had been preprocessed
before it was given to a solver? The paper targets a suite of commonly-used
preprocessing techniques and shows how to reconstruct certificates for them. On
the negative side, the paper discusses certain limitations of the
currently-used proof systems in the light of preprocessing. The presented
techniques were implemented and evaluated in the state-of-the-art QBF
preprocessor bloqqer.Comment: LPAR 201
Event by event analysis of collision induced cluster ion fragmentation: sequential monomer evaporation versus fission reactions
IP
Improving MCS Enumeration via Caching
Enumeration of minimal correction sets (MCSes) of conjunctive normal form formulas is a central and highly intractable problem in infeasibility analysis of constraint systems. Often complete enumeration of MCSes is impossible due to both high computational cost and worst-case exponential number of MCSes. In such cases partial enumeration is sought for, finding applications in various domains, including axiom pinpointing in description logics among others. In this work we propose caching as a means of further improving the practical efficiency of current MCS enumeration approaches, and show the potential of caching via an empirical evaluation.Peer reviewe
Logic, Probability and Action: A Situation Calculus Perspective
The unification of logic and probability is a long-standing concern in AI,
and more generally, in the philosophy of science. In essence, logic provides an
easy way to specify properties that must hold in every possible world, and
probability allows us to further quantify the weight and ratio of the worlds
that must satisfy a property. To that end, numerous developments have been
undertaken, culminating in proposals such as probabilistic relational models.
While this progress has been notable, a general-purpose first-order knowledge
representation language to reason about probabilities and dynamics, including
in continuous settings, is still to emerge. In this paper, we survey recent
results pertaining to the integration of logic, probability and actions in the
situation calculus, which is arguably one of the oldest and most well-known
formalisms. We then explore reduction theorems and programming interfaces for
the language. These results are motivated in the context of cognitive robotics
(as envisioned by Reiter and his colleagues) for the sake of concreteness.
Overall, the advantage of proving results for such a general language is that
it becomes possible to adapt them to any special-purpose fragment, including
but not limited to popular probabilistic relational models
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