Assessing the Utility of Item Response Models: Computerized Adaptive Testing

How has Item Response Theory helped solve problems in the development and use of computer-adaptive tests? Do we need to balance item content with computer-adaptive tests? Could we use IRT to evaluate unusual responses to computer-delivered tests?     

Constructing a Landscape for Postwar Science: Roger Revelle,the Scripps Institution and the University of California,San Diego

This paper explores Roger Revelle's activities in oceanography and institution-building during and after the Second World War. In particular, it explores his shift from a wartime acceptance of science serving mission-oriented objectives, to a defence ofthe distinction between basic and applied science. For Revelle, the Federal government, and especially the military, became theguarantor of basic research in oceanography. This understanding led him to privilege military sponsorship over contract research,and the physical over the biological sciences. He drew upon that understanding to construct a unique institutional geography for science in southern California.     

Institutional Repositories: Faculty Deposits,Marketing, and the Reform of Scholarly Communication

This study explores faculty deposits in institutional repositories (IR) within selected disciplines and identifies the diverse navigational paths to IR sites from library Web site homepages. The statistical relationship between the development of an IR and the presence of a Web site dedicated to the reform of traditional scholarly communication is also explored. The implications for the development of institutional repositories are highlighted.     

Infinite sequences and their h-type indices

Starting from the notion of h-type indices for infinite sequences we investigate if these indices satisfy natural inequalities related to the arithmetic, the geometric and the harmonic mean. If f denotes an h-type index, such as the h- or the g-index, then we investigate inequalities such as min(f(X),f(Y)) ≤ f((X?+?Y)/2) ≤ max(f(X), f(Y)). We further investigate if: f(min(X,Y)) = min(f(X),f(Y)) and if f(max(X,Y)) = max(f(X),f(Y)). It is shown that the h-index satisfies all the equalities and inequalities we investigate but the g-index does not always, while it is always possible to find a counterexample involving the R-index. This shows that the h-index enjoys a number of interesting mathematical properties as an operator in the partially ordered positive cone (R⁺)^∞ of all infinite sequences with non-negative real values.In a second part we consider decreasing vectors X and Y with components at most at distance d. Denoting by D the constant sequence (d,d,d, …) and by Y-D the vector (max(y_r-d), 0)_r, we prove that under certain natural conditions, the double inequality h(Y-D) ≤ h(X) ≤ h(Y?+?D) holds.     

网络信息检索中利用the Staceys测度方法提高逻辑运算效率的思考

网络信息检索中,逻辑运算符AND连接检索词的顺序很大程度上会影响检索效率.论文首先分析、介绍了the Staceys测度方法在改善AND检索效率中发挥的作用,并在此基础上提出简化了的测度算法,最后通过实例说明其实现步骤.