Construct validity of scores from the Connor-Davidson Resilience Scale in a sample of postsecondary students with disabilities

Although theory posits a multidimensional structure of resilience, studies have supported a unidimensional solution for data obtained from the commonly used Connor–Davidson Resilience Scale (CD-RISC). This study investigated the latent structure of CD-RISC responses in a sample of postsecondary students with disabilities. Furthermore, the validity of CD-RISC scores was examined with respect to career optimism and well-being. The analyses were conducted using confirmatory factor analysis and exploratory structural equation modeling (ESEM). Results supported a bifactor-ESEM representation of the CD-RISC data that accounts for construct-relevant multidimensionality in scores due to the presence of general and specific factors and the fallibility of indicators as pure reflections of the constructs they measure. Although three specific factors showed meaningful residual specificity over and above the general factor, two specific factors were weakly defined with little meaningful residual specificity. However, these factors may retain some utility in the bifactor-ESEM model insofar as they control for limited levels of residual covariance in items. Evidence was also obtained for relations of the general and substantively interpretable specific factors with career optimism and well-being. The results of the study provide validation data for the CD-RISC and clarify recent research converging on seemingly disparate unidimensional and multidimensional solutions

pBWT: Achieving succinct data structures for parameterized pattern matching and related problems

The fields of succinct data structures and compressed text indexing have seen quite a bit of progress over the last two decades. An important achievement, primarily using techniques based on the Burrows-Wheeler Transform (BWT), was obtaining the full functionality of the suffix tree in the optimal number of bits. A crucial property that allows the use of BWT for designing compressed indexes is order-preserving suffix links. Specifically, the relative order between two suffixes in the subtree of an internal node is same as that of the suffixes obtained by truncating the furst character of the two suffixes. Unfortunately, in many variants of the text-indexing problem, for e.g., parameterized pattern matching, 2D pattern matching, and order-isomorphic pattern matching, this property does not hold. Consequently, the compressed indexes based on BWT do not directly apply. Furthermore, a compressed index for any of these variants has been elusive throughout the advancement of the field of succinct data structures. We achieve a positive breakthrough on one such problem, namely the Parameterized Pattern Matching problem. Let T be a text that contains n characters from an alphabet , which is the union of two disjoint sets: containing static characters (s-characters) and containing parameterized characters (p-characters). A pattern P (also over ) matches an equal-length substring S of T i the s-characters match exactly, and there exists a one-to-one function that renames the p-characters in S to that in P. The task is to find the starting positions (occurrences) of all such substrings S. Previous index [Baker, STOC 1993], known as Parameterized Suffix Tree, requires (n log n) bits of space, and can find all occ occurrences in time O(jPj log +occ), where = jj. We introduce an n log +O(n)-bit index with O(jPj log +occlog n log ) query time. At the core, lies a new BWT-like transform, which we call the Parame- terized Burrows-Wheeler Transform (pBWT). The techniques are extended to obtain a succinct index for the Parameterized Dictionary Matching problem of Idury and Schaer [CPM, 1994]

Structural Pattern Matching - Succinctly

Let T be a text of length n containing characters from an alphabet Sigma, which is the union of two disjoint sets: Sigma_s containing static characters (s-characters) and Sigma_p containing parameterized characters (p-characters). Each character in Sigma_p has an associated complementary character from Sigma_p. A pattern P (also over Sigma) matches an equal-length substring $S$ of T iff the s-characters match exactly, there exists a one-to-one function that renames the p-characters in S to the p-characters in P, and if a p-character x is renamed to another p-character y then the complement of x is renamed to the complement of y. The task is to find the starting positions (occurrences) of all such substrings S. Previous indexing solution [Shibuya, SWAT 2000], known as Structural Suffix Tree, requires Theta(nlog n) bits of space, and can find all occ occurrences in time O(|P|log sigma+ occ), where sigma = |Sigma|. In this paper, we present the first succinct index for this problem, which occupies n log sigma + O(n) bits and offers O(|P|logsigma+ occcdot log n logsigma) query time

Preparing Australian Special Educators: Courses and Content

: The characteristics and content of post-graduate courses in special and/or inclusive teacher education in Australian universities were examined using publicly available material on university websites. Content analysis was guided by a set of content area elements covering desirable skills and knowledge for special educators that were identified in the Australian literature. The presence or absence of these content elements in each course and in core or elective units was coded for 28 courses from 21 universities. All or most courses covered generic content such as teaching strategies and evaluating and using research. However, more specialist content, such as explicit teaching strategies and instruction in literacy and numeracy, was absent from over half the courses. The implications of these findings are discussed in the context of the limitations necessarily imposed by the inclusion of only publicly available online information

Forbidden Extension Queries

Document retrieval is one of the most fundamental problem in information retrieval. The objective is to retrieve all documents from a document collection that are relevant to an input pattern. Several variations of this problem such as ranked document retrieval, document listing with two patterns and forbidden patterns have been studied. We introduce the problem of document retrieval with forbidden extensions. Let D={T_1,T_2,...,T_D} be a collection of D string documents of n characters in total, and P^+ and P^- be two query patterns, where P^+ is a proper prefix of P^-. We call P^- as the forbidden extension of the included pattern P^+. A forbidden extension query asks to report all occ documents in D that contains P^+ as a substring, but does not contain P^- as one. A top-k forbidden extension query asks to report those k documents among the occ documents that are most relevant to P^+. We present a linear index (in words) with an O(|P^-| + occ) query time for the document listing problem. For the top-k version of the problem, we achieve the following results, when the relevance of a document is based on PageRank: - an O(n) space (in words) index with O(|P^-|log sigma+ k) query time, where sigma is the size of the alphabet from which characters in D are chosen. For constant alphabets, this yields an optimal query time of O(|P^-|+ k). - for any constant epsilon > 0, a |CSA| + |CSA^*| + Dlog frac{n}{D} + O(n) bits index with O(search(P)+ k cdot tsa cdot log ^{2+epsilon} n) query time, where search(P) is the time to find the suffix range of a pattern P, tsa is the time to find suffix (or inverse suffix) array value, and |CSA^*| denotes the maximum of the space needed to store the compressed suffix array CSA of the concatenated text of all documents, or the total space needed to store the individual CSA of each document

The experiences of students with mental health difficulties at an Australian regional university: overcoming barriers to successful educational and employment outcomes

Educational achievement is consistently linked to better employment outcomes for individuals, but navigating through higher education can be particularly challenging for regional, rural, and remote students. Some individuals face additional difficulties linked to personal disability, and a particularly vulnerable group are those individuals with an identified mental health issue. Flexibility in study options can enable many students to access higher education, with distance education, a choice for many living regionally, providing both opportunities and challenges for study. The research presented here is part of a project funded by the National Centre for Student Equity in Higher Education (NCSEHE), which explored the lived experiences of individuals with a disability at a regional Australian university. The overall focus for the research was to understand individual resilience and what enables some students with mental health problems to be successful in their educational achievement. The present research draws on findings from semi-structured interviews with nine individuals identifying with mental health difficulties. Subsequent analysis followed Braun and Clarke’s (2006) approach to thematic analysis. The key themes identified were those of disclosure and the decision to register or not with disability services; interactions with ‘faculty’; and strategies for positive educational engagement. We concluded that a major challenge in the higher education sector relates to building disability support services that are responsive to the needs of students with a psychological disability. The findings from this study advance knowledge in understanding what strategies a successful student with a mental health issue draws upon in order to succeed, and what implications this may have for the shaping of student support services

Space-Time Trade-Offs for the Shortest Unique Substring Problem

Given a string X[1, n] and a position k in [1, n], the Shortest Unique Substring of X covering k, denoted by S_k, is a substring X[i, j] of X which satisfies the following conditions: (i) i leq k leq j, (ii) i is the only position where there is an occurrence of X[i, j], and (iii) j - i is minimized. The best-known algorithm [Hon et al., ISAAC 2015] can find S k for all k in [1, n] in time O(n) using the string X and additional 2n words of working space. Let tau be a given parameter. We present the following new results. For any given k in [1, n], we can compute S_k via a deterministic algorithm in O(n tau^2 log n tau) time using X and additional O(n/tau) words of working space. For every k in [1, n], we can compute S_k via a deterministic algorithm in O(n tau^2 log n/tau) time using X and additional O(n/tau) words and 4n + o(n) bits of working space. For both problems above, we present an O(n tau log^{c+1} n)-time randomized algorithm that uses n/ log c n words in addition to that mentioned above, where c geq 0 is an arbitrary constant. In this case, the reported string is unique and covers k, but with probability at most n^{-O(1)}may not be the shortest. As a consequence of our techniques, we also obtain similar space-and-time tradeoffs for a related problem of finding Maximal Unique Matches of two strings [Delcher et al., Nucleic Acids Res. 1999]

Categorical Range Reporting with Frequencies

In this paper, we consider a variant of the color range reporting problem called color reporting with frequencies. Our goal is to pre-process a set of colored points into a data structure, so that given a query range Q, we can report all colors that appear in Q, along with their respective frequencies. In other words, for each reported color, we also output the number of times it occurs in Q. We describe an external-memory data structure that uses O(N(1+log^2D/log N)) words and answers one-dimensional queries in O(1 +K/B) I/Os, where N is the total number of points in the data structure, D is the total number of colors in the data structure, K is the number of reported colors, and B is the block size. Next we turn to an approximate version of this problem: report all colors sigma that appear in the query range; for every reported color, we provide a constant-factor approximation on its frequency. We consider color reporting with approximate frequencies in two dimensions. Our data structure uses O(N) space and answers two-dimensional queries in O(log_B N +log^*B + K/B) I/Os in the special case when the query range is bounded on two sides. As a corollary, we can also answer one-dimensional approximate queries within the same time and space bounds