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21.
This review of the SAD hypothesis of Kamstra et al. (2003), hereafter KKL (2003), isolates four new problems. First, the KKL (2003) statistical model does not test the KKL (2003) SAD hypothesis. Second, KKL (2003) do not properly interpret their results. Third, KKL (2003) incorrectly specify the sign of the SAD effect in the winter. The revised SAD hypothesis is that hours of night have a negative influence on stock returns in the fall and in the winter. Fourth, the statistical tests do not support either the KKL (2003) hypothesis or the revised SAD hypothesis. 相似文献
22.
Khaled Moustafa 《Accountability in research》2013,20(4):246-248
A strong trend to move from print to online publication is largely perceived in scientific and nonscientific fields. A growing number of publishers increasingly opt for online publication as an option or a compulsory alternative. From readers’ perspective, this is a highly appreciated facility, but from the author’s, things are different mainly because of excessive article processing charges (APC) that make the open access system sometimes as a hindrance for many authors but a lucrative enterprise for many shareholders, enticing the most traditional and conservative publishers. 相似文献
23.
AbstractThis paper develops a tailored case study design for strategic asset management research. It draws on the notions of ‘contextualist approach’ and ‘retroductive strategy’ used in case study research, and follows the multiple embedded-case design advocated within qualitative research. Using a published asset management research study as a primer, it demonstrates the application of the proposed research design and its methodological rigour. This research design could serve as a reference framework, as well as a research instrument, for guiding asset management research. As such, it facilitates the development of theory that accounts for the multi-faceted nature and current priorities of asset management. Overall, this research design helps determine what activities to be incorporated into an asset management program to enhance an organization’s ability to capture value from its operations system. In so doing, it promotes a holistic perspective on asset management that is currently lacking in the literature. 相似文献
24.
Khaled Moustafa 《Accountability in research》2016,23(4):230-244
Multiple inherent biases related to different citation practices (for e.g., self-citations, negative citations, wrong citations, multi-authorship-biased citations, honorary citations, circumstantial citations, discriminatory citations, selective and arbitrary citations, etc.) make citation-based bibliometrics strongly flawed and defective measures. A paper can be highly cited for a while (for e.g., under circumstantial or transitional knowledge), but years later it may appear that its findings, paradigms, or theories were untrue or invalid anymore. By contrast, a paper may remain shelved or overlooked for years or decades, but new studies or discoveries may actualize its subject at any moment. As citation-based metrics are transformed into “commercial activities,” the “citation credit” should be considered on a commercial basis too, in the sense that “citation credit” should be shared out as a “citation dividend” by shareholders (coauthors) averagely or proportionally to their contributions but not fully appropriated by each of them. At equal numbers of citations, the greater number of authors, the lower “citation credit” should be and vice versa. Overlooking the presence of distorted and subjective citation practices makes many people and administrators “obsessed” with the number of citations to such an extent to run after “highly cited” authors and to create specialized citation databases for commercial purposes. Citation-based bibliometrics, however, are unreliable and unscientific measures; citation counts do not mean that a more cited work is of a higher quality or accuracy than a less cited work because citations do not measure the quality or accuracy. Citations do not mean that a highly cited author or journal is more commendable than a less cited author or journal. Citations are not more than countable numbers: no more, no less. 相似文献
25.
Khaled Hassine Aurore Marcouyeux Thouraya Annabi-Attia Ghozlane Fleury-Bahi 《Social indicators research》2014,119(3):1603-1612
The objective of this paper is to study the quality of life in the neighborhood by developing a scale to measure the perceived environmental quality of life. Items of the scale were produced using semi-structured interviews. Three main dimensions of environmental quality of life (EQL) were recognized by an exploratory factor analysis applied on 732 participants. This factor structure was then subjected to a confirmatory factor analysis performed on a second sample of 791 people. The satisfactory internal consistency of the three EQL dimensions, the good fit of the measurement model to the data and the stability of the factorial structure all confirm the excellent psychometric qualities of the designed scale. 相似文献
26.
UNICEF commissioned a qualitative evaluation of a program in which two partners conducted prevention activities concerning HIV/AIDS and STIs amongst youth in Madagascar. The evaluation assessed project activities and conducted a practical exercise in focus group methodology, following a workshop on evaluation techniques. Information was collected from a wide range of people, including 441 participants in 46 focus groups in nine sites. Six sites were areas of project activities and three sites were targeted for future activities. Clubs that integrated HIV/AIDS and STI information into their regular activities were most successful in their information, education and communication activities. A more participatory approach is recommended, to achieve a better match between target groups and messages delivered, and to foster trust and support. Another challenge remaining is to address fears and stigma through advocacy for the care and support of affected people. 相似文献
27.
ABSTRACTThe sum of independent exponential random variables – the hypoexponential random variables – plays an important role of modeling in many domains. Khuong and Kong in (2006) were concerned in evaluating the performance of some diversity scheme, which deals with the problem of finding the probability density function of this hypoexponential random variable. They considered a particular case of m independent exponential random variable, when l random variables have the same mean and m ? l remaining random variables of different means and they found a closed expression of its probability density function. In this paper, we consider the general case of the hypoexponential random variable when the means do not have to be distinct. We find a more simple and general closed expression of its probability density function than that of Khuong and Kong. This expression is obtained using a new defined matrix called the Kad matrix, which is similar to the general Vandermonde matrix. Eventually, we present an application illustrating our work. 相似文献
28.
Khaled Elbassioni Kazuhisa Makino Imran Rauf 《Journal of Combinatorial Optimization》2011,22(3):293-304
Golumbic et al. (Discrete Appl. Math. 154:1465–1477, 2006) defined the readability of a monotone Boolean function f to be the minimum integer k such that there exists an ∧−∨-formula equivalent to f in which each variable appears at most k times. They asked whether there exists a polynomial-time algorithm, which given a monotone Boolean function f, in CNF or DNF form, checks whether f is a read-k function, for a fixed k. In this paper, we partially answer this question already for k=2 by showing that it is NP-hard to decide if a given monotone formula represents a read-twice function. It follows also from
our reduction that it is NP-hard to approximate the readability of a given monotone Boolean function f:{0,1}
n
→{0,1} within a factor of
O(n)\mathcal{O}(n)
. We also give tight sublinear upper bounds on the readability of a monotone Boolean function given in CNF (or DNF) form,
parameterized by the number of terms in the CNF and the maximum size in each term, or more generally the maximum number of
variables in the intersection of any constant number of terms. When the variables of the DNF can be ordered so that each term
consists of a set of consecutive variables, we give much tighter logarithmic bounds on the readability. 相似文献