Browsing by Author "Fu, Bo"
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Item Accountable logging and its applications to intrusion detection(University of Alabama Libraries, 2013) Fu, Bo; Xiao, Yang; University of Alabama TuscaloosaToday's computer and network systems were not originally designed for accountability which plays a crucial role in information assurance systems. To assure accountability, each entity in the system should be held responsible for its own behaviors so that the entity is a part of larger chains of the system's accountability. To achieve accountability, a flow-net methodology that records events as well as relations between events was proposed. The multi-layer feature of computer and network systems brings us the chance to achieve multiple degrees of accountability, which means we are able to acknowledge the system's behaviors at different levels of accountability. In this dissertation, a multi-resolution flow-net is proposed for achieving multi-layer accountability. Moreover, Intrusion Detection Systems that monitor malicious behaviors in computer and network systems play an important role in assuring system security. Flow-net that builds comprehensive logs and helps track events is able to order to record system and user behaviors. In this dissertation, an Intrusion Detection Scheme by Flow-Net Based Fingerprint (IDS-FF) scheme is proposed for detecting fingerprints of malicious behaviors. As an application of the IDS-FF scheme, we use it to detect intrusions in TCP/IP networks. Furthermore, in order to detect the intrusions that disguise themselves as regular behaviors in networks, we apply the IDS-FF scheme with cryptography techniques in TCP/IP networks.Item Bioimpedance Applied on Skeletal Muscle Assessing to Resistance Training Effects(University of Alabama Libraries, 2020) Fu, Bo; Freeborn, Todd J.; University of Alabama TuscaloosaElectrical impedance measurements of biological tissues, termed as bioimpedance, quantify the passive electrical properties of biological tissues including skeletal muscles. Resistance training is important to skeletal muscle in terms of strength gaining, but could introduce fatigue and damage with improper training protocols. For this dissertation, the effect of bicep curl exercise is studied using bioimpedance measurement on localized bicep tissue. Several research tasks are set for this dissertation. Firstly, the accuracy and limitations of impedance measurements with Keysight E4990A impedance analyzer under high residual impedance were studied, with OSL compensation, tetrapolar configuration and 10 kHz to 100 kHz recommended for bioimpedance measurement for maximum accuracy. Secondly, localized bioimpedance was used to assess the changes of bicep tissue of healthy young adults participating in isotonic exercise designed to induce skeletal muscle fatigue with significant changes of pre- and post-exercise impedances observed, caused by the change of muscle property. Next, bioimpedance experiment was further performed on bicep tissue of healthy young adults participating and recovering from eccentric bicep curls exercise with significant change of impedance observed 72 and 96 hours post-exercise, different from isotonic experiment result in terms of recovery time potentially due to the delayed-onset feature of eccentric exercise. Lastly, the use of an equivalent electrical circuit, the Cole-impedance model, to represent bicep tissue bioimpedance was evaluated by fitting the data collected from isotonic and eccentric exercises. Significant changes in Cole impedance parameters, Rinf, R1 and C were observed in isotonic eccentric exercise, proposed to be related to muscle swelling and architecture alteration, respectively. Conclusions and contributions of the current study were shown at the end, as well as limitations and future improvements.Item Cole-impedance parameters representing biceps tissue bioimpedance in healthy adults and their alterations following eccentric exercise(Elsevier, 2020) Fu, Bo; Freeborn, Todd J.; University of Alabama TuscaloosaThe purpose of this study is to identify if participation in an eccentric exercise protocol altered the Cole-impedance model parameters that represent localized bicep tissue bioimpedance. This supports continued efforts to identify which features of tissue bioimpedance may be effective markers to non-invasively identify skeletal muscle damage. Here, the Cole-impedance model parameters that best fit the localized electrical impedance of exercised (using an eccentric stimulus) and unexercised biceps of 6 participants (collected before, immediately after and at 24 h, 48 h, 72 h and 96 h) are determined using a numerical optimization technique. Statistical tests comparing the pre-exercise and post-exercise model parameters report significant decreases in R-infinity and R-1 with significant increases in Cat 72 h and 96 h post-exercise for exercised biceps (aligning with noted periods of peak swelling). These changes in R-infinity, R-1, and C were not observed in the unexercised biceps. These results support that the C parameter of the Cole-impedance model fit to bioimpedance data may be a suitable marker for identifying skeletal muscle damage. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Cairo University.Item Fatigue-Induced Cole Electrical Impedance Model Changes of Biceps Tissue Bioimpedance(MDPI, 2018) Freeborn, Todd J.; Fu, Bo; University of Alabama TuscaloosaBioimpedance, or the electrical impedance of biological tissues, describes the passive electrical properties of these materials. To simplify bioimpedance datasets, fractional-order equivalent circuit presentations are often used, with the Cole-impedance model being one of the most widely used fractional-order circuits for this purpose. In this work, bioimpedance measurements from 10 kHz to 100 kHz were collected from participants biceps tissues immediately prior and immediately post completion of a fatiguing exercise protocol. The Cole-impedance parameters that best fit these datasets were determined using numerical optimization procedures, with relative errors of within approximately +/- 0.5% and +/- 2% for the simulated resistance and reactance compared to the experimental data. Comparison between the pre and post fatigue Cole-impedance parameters shows that the R-infinity, R-1, and f(p) components exhibited statistically significant mean differences as a result of the fatigue induced changes in the study participants.