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You searched for subject:(Clock AND cube drawing performance). Showing records 1 – 2 of 2 total matches.

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Texas Tech University

1. Liu, Yin. A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations.

Degree: Human Development and Family Studies, 2011, Texas Tech University

This study is a secondary data analysis focusing on describing elders’ intra-individual variability in their initial level of cognitive performance and their rate of cognitive change, as well as elders’ inter-individual variability in their initial level of cognitive performance and their rate of cognitive change in relation to the covariates of gender, college education, self-reported memory decline, and functional impairment. A multilevel model was fit into two waves of supplementary data in years 2000 and 2004 from the larger Longitudinal Studies of Generations (LSOG) using HLM software. Cases with missing data were deleted, leaving 180 (N) elders aged 55 and over for 2 sets of 2-level analysis with outcome variables of the clock drawing performance score, and the cube drawing performance score. All the covariates in the level-2 equations were dichotomized. In the analysis with the clock score as outcome variable, no significant effect was found for any of the covariates. In the analysis with the cube score as outcome variable, functional impairment was found to be significantly related to both elders’ cognitive function at age 70, and predicted elders’ rate of cognitive change in a 4-year period. Specifically, other things being equal, for people who had some functional impairment, their cube drawing performance was .034 logits lower than those who did not have any functional impairment at age 70. However, having at least some functional impairment was associated with a .004 logits increment to the growth rate of cube drawing performance. Possible reasons for both non-significant and significant effects’ of covariates on clock and cube drawing performance were discussed in light of findings from prior studies, characteristics of the present sample, and limitations of clock and cube drawing tasks as valid and reliable measures of cognitive performance. Directions for future research were suggested. Advisors/Committee Members: Feng, Du (Committee Chair), Bell, Nancy J. (committee member), Cong, Zhen (committee member).

Subjects/Keywords: Cognitive performance; Clock and cube drawing performance; Multilevel model; Longitudinal study of generations (LSOG)

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Liu, Y. (2011). A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations. (Thesis). Texas Tech University. Retrieved from http://hdl.handle.net/2346/ETD-TTU-2011-08-1679

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Liu, Yin. “A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations.” 2011. Thesis, Texas Tech University. Accessed October 26, 2020. http://hdl.handle.net/2346/ETD-TTU-2011-08-1679.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Liu, Yin. “A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations.” 2011. Web. 26 Oct 2020.

Vancouver:

Liu Y. A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations. [Internet] [Thesis]. Texas Tech University; 2011. [cited 2020 Oct 26]. Available from: http://hdl.handle.net/2346/ETD-TTU-2011-08-1679.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Liu Y. A multilevel analysis of elders’ cognitive performance using data from the longitudinal study of generations. [Thesis]. Texas Tech University; 2011. Available from: http://hdl.handle.net/2346/ETD-TTU-2011-08-1679

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Indian Institute of Science

2. Pillai, N Rajesh. New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers.

Degree: PhD, Faculty of Engineering, 2015, Indian Institute of Science

Algebraic attacks constitute an effective class of cryptanalytic attacks which have come up recently. In algebraic attacks, the relations between the input, output and the key are expressed as a system of equations and then solved for the key. The main idea is in obtaining a system of equations which is solvable using reasonable amount of resources. The new approaches proposed in this work and experimental studies on the existing algebraic attacks on stream ciphers will be presented. In the first attack on filter generator, the input-output relations are expressed in conjunctive normal form. The system of equations is then solved using modified Zakrevskij technique. This was one of the earliest algebraic attacks on the nonlinear filter generator. In the second attack, we relaxed the constraint on algebraic attack that the entire system description be known and the output sequence extension problem where the filter function is unknown is considered. We modeled the problem as a multivariate interpolation problem and solved it. An advantage of this approach is that it can be adapted to work for noisy output sequences where as the existing algebraic attacks expect the output sequence to be error free. Adding memory to filter/combiner function increases the degree of system of equations and finding low degree equations in this case is computeintensive. The method for computing low degree relations for combiners with memory was applied to the combiner in E0 stream cipher. We found that the relation given in literature [Armknecht and Krause] was incorrect. We obtained the correct equation and verified its correctness. A time-data size trade off attack for clock controlled filter generator was developed. The time complexity and the data requirements are in between the two approaches used in literature. A recent development of algebraic attacks - the Cube attack was studied. Cube attack on variants of Trivium were proposed by Dinur and Shamir where linear equations in key bits were obtained by combining equations for output bit for same key and a set of Initialization Vectors (IVs). We investigated the effectiveness of the cube attack on Trivium. We showed that the linear equations obtained were not general and hence the attack succeeds only for some specific values of IVs. A reason for the equations not being general is given and a modification to the linear equation finding step suggested. Advisors/Committee Members: Shankar, Priti (advisor), Veni Madhavan, C E (advisor).

Subjects/Keywords: Cryptography; Algebraic Attacks; Stream Ciphers; Cube Attacks; Stream Ciphers - Algebraic Attacks; Filter Generators - Algebraic Attacks; Trivium; Nonlinear Filter Generator; Nonlinear Feedforward Generator; Clock Controlled Filter Generator; Computer Science

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Pillai, N. R. (2015). New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers. (Doctoral Dissertation). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/2436

Chicago Manual of Style (16th Edition):

Pillai, N Rajesh. “New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers.” 2015. Doctoral Dissertation, Indian Institute of Science. Accessed October 26, 2020. http://etd.iisc.ac.in/handle/2005/2436.

MLA Handbook (7th Edition):

Pillai, N Rajesh. “New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers.” 2015. Web. 26 Oct 2020.

Vancouver:

Pillai NR. New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers. [Internet] [Doctoral dissertation]. Indian Institute of Science; 2015. [cited 2020 Oct 26]. Available from: http://etd.iisc.ac.in/handle/2005/2436.

Council of Science Editors:

Pillai NR. New Approaches And Experimental Studies On - Alegebraic Attacks On Stream Ciphers. [Doctoral Dissertation]. Indian Institute of Science; 2015. Available from: http://etd.iisc.ac.in/handle/2005/2436

.