MS, University of Cincinnati, 2018, Engineering and Applied Science: Civil Engineering

This paper presents an evaluation of the shear lag factor for HSS tension members connected with two side plate gussets with longitudinal welds as given in Case 6 of Table D3.1 of AISC 360-16. The current AISC Specification for Case 6 does not permit weld lengths less than the perpendicular distance between the welds, and has the potential of producing negative shear lag factors. Similar issues previously existed for members given in Case 4 of Table 3.1. However, the AISC 360-16 Specification has adopted a mathematical model proposed by Fortney and Thornton for Case 4 of Table D3.1. The work presented in this paper offers: (1) a mathematical model for calculating the shear lag factor for Case 6 derived by repurposing the model adopted by AISC for Case 4 of Table D3.1; (2) the results of a parametric study comparing the results of the new mathematical model to the results using the current AISC method, and; (3) discusses the protocols developed for use in finite element analysis to evaluate the effectiveness of the proposed mathematical model. The proposed new mathematical model will permit longitudinal weld lengths less than the perpendicular distance between the welds, and removes the possibility of calculating a negative shear lag factor, while better representing the redistribution of cross-sectional stress near the connection region.

Committee: Gian Andrea Rassati Ph.D. (Committee Chair); Patrick Fortney Ph.D. (Committee Member); Bahram Shahrooz Ph.D. (Committee Member) Subjects: Civil Engineering

Master of Science in Electrical Engineering, Cleveland State University, 2021, Washkewicz College of Engineering

In this thesis, we draw attention to the problem of cross-service attacks, that is, attacks that exploit information collected about users from one service to launch an attack on the same users on another service. With the increased deployment and use of what fundamentally are integrated-services networks, such as 4G/LTE networks and now 5G, we expect that cross-service attacks will become easier to stage and therefore more prevalent. As running example to illustrate the effectiveness and the potential impact of cross-service attacks we will use the problem of account association in 4G/LTE networks. Account association attacks aim at determining whether a target mobile phone number is associated with a particular online account. In the case of 4G/LTE, the adversary launches the account association attacks by sending SMS messages to the target phone number and analyzing patterns in traffic related to the online account. We evaluate the proposed attacks in both a local 4G/LTE testbed and a major commercial 4G/LTE network. Our extensive experiments show that the proposed attacks can successfully identify account association with close-to-zero false negative and false positive rates. Our experiments also illustrate that the proposed attacks can be launched in a way that the victim receives no indication of being under attack.

Committee: Ye Zhu (Committee Chair); Yongjain Fu (Committee Member); Sui-Tung Yau (Committee Member) Subjects: Computer Engineering; Computer Science; Electrical Engineering; Information Technology; Technology

MS, University of Cincinnati, 2017, Engineering and Applied Science: Civil Engineering

This study examines a variation on the prequalified double tee seismic moment connection as a candidate for use in seismic special moment frames using hollow columns. T-stubs are attached to the column by very long bolts passing clear through the hollow center. The column is then filled with grout in the connection region only. The grout surrounds the long bolt shanks inside and provides resistance to local failures. Fourteen connections were designed according to the double tee connection design procedure, for beams from 24 to 33 inches deep and columns from 14 to 22 inches wide. The connections were modeled with a monotonic displacement in Abaqus to find the moment-rotation response. All of the connections maintained adequate strength at the level of rotation required for special moment frames. Seven of the connections exhibited adequate initial stiffness to be considered fully restrained at some service moment. A cyclic analysis similar to the one to be used for prequalification testing was performed for one design. The results showed enough similarity to the monotonic analysis that cyclic analyses were considered unnecessary for preliminary evaluation; the monotonic analyses were considered good approximations of the connections' behavior under cyclic loading.

Committee: Gian Rassati Ph.D. (Committee Chair); Thomas M. Burns Ph.D. (Committee Member); James Swanson Ph.D. (Committee Member) Subjects: Civil Engineering