Effective Memory Diversification in Legacy Systems

Memory corruption error is one of the critical security attack vectors against a wide range of software. Addressing this problem, modern compilers provide multiple features to fortify the software against such errors. However, applying compiler-based memory defense is problematic in legacy systems we often encounter in industry or military environments because source codes are unavailable. In this study, we propose memory diversification techniques tailored for legacy binaries to which we cannot apply state-of- the-art compiler-based solutions. The basic idea of our approach is to automatically patch the machine code instructions of each legacy system differently (e.g., a drone, or a vehicle firmware) without altering any semantic behavior of the software logic. As a result of our system, attackers must create a specific attack payload for each target by analyzing the particular firmware, thus significantly increasing exploit development time and cost. Our approach is evaluated by applying it to a stack and heap of multiple binaries, including PX4 drone firmware and other Linux utilities

Associations of reproductive factors with incidence of myocardial infarction and ischemic stroke in postmenopausal women: a cohort study

Background To assess the association between the reproductive factors of age at menarche, age at menopause, and reproductive span and the incidence of myocardial infarction (MI) and ischemic stroke (IS). Methods We used a population-based retrospective cohort study from the National Health Insurance Service database of Korea including a total of 1,224,547 postmenopausal women. Associations between age at menarche (≤ 12, 13–14 [reference], 15, 16, and ≥ 17years), age at menopause (< 40, 40–45, 46–50, 51–54 [reference], and ≥ 55years), and reproductive span (< 30, 30–33, 34–36, 37–40 [reference], and ≥ 41years) and the incidence of MI and IS were assessed by Cox proportional hazard models with adjustment for traditional cardiovascular risk factors and various reproductive factors. Results During a median follow-up of 8.4years, 25,181 MI and 38,996 IS cases were identified. Late menarche (≥ 16years), early menopause (≤ 50years), and short reproductive span (≤ 36years) were linearly associated with a 6%, 12–40%, and 12–32% higher risk of MI, respectively. Meanwhile, a U-shaped association between age at menarche and risk of IS was found, with a 16% higher risk in early menarche (≤ 12years) and a 7–9% higher risk in late menarche (≥ 16years). Short reproductive span was linearly associated with an increased risk of MI, whereas both shorter and longer reproductive spans were associated with an increased risk of IS. Conclusions This study demonstrated different patterns of association between age at menarche and incidence of MI and IS: a linear association for MI versus a U-shaped association for IS. Female reproductive factors in addition to traditional cardiovascular risk factors should be considered when assessing overall cardiovascular risk in postmenopausal women

Doctoral Recitals

Recital presented at the UNT College of Music Voertman Hall in partial fulfillment of the Doctor of Musical Arts (DMA) degree

Fuzzability Testing Framework for Incomplete Firmware Binary

Fuzzing is a practical approach for finding bugs in various software. So far, a number of fuzzers have been introduced based on new ideas towards enhancing the efficiency in terms of increasing code coverage or execution speed. The majority of such work predicates under the assumption that they have sound executable binary or source code to transform the target program as a whole. However, in legacy systems, source codes are often unavailable and even worse, some binaries do not provide a sound executable environment (e.g., partially recovered firmware). In this paper, we provide FT-Framework: fuzzability testing framework based on forced execution for binaries such as firmware chunks recovered in abnormal way so that they are hard to execute/analyze from intended booting phase. The essence of our work is to automatically classify functions inside a binary which we can apply coverage-guided fuzzing via forced execution. We evaluate FT-Framework using PX4 and ArduPilot firmwares which is based on 32-bit ARM architecture and demonstrate the efficacy of this approach and limitations

Fabrication of wafer-scale free-standing quantum dot/polymer nanohybrid films for white-light-emitting diodes using an electrospray method

Wafer-scale free-standing quantum dot (QD)/polymer nanohybrid (NHB) based down-conversion (DC) phosphor films for remote-type white-light-emitting diodes (W-LEDs) are developed. Organic-soluble and nontoxic dodecanethiol-capped AgIn5S8/ZnS QDs and a thermoplastic polymer, poly(methyl methacrylate) (PMMA), are used as a DC material and a matrix respectively. The NHB based DC films are successfully fabricated by an electrospray (e-spray) method and the extraordinarily high concentration of QDs are able to be loaded in the resulting e-sprayed NHB films. The wafer-scale free-standing NHB films are also achieved by using a delamination method with which the e-sprayed films on a thin interlayer of a water-soluble polymer are detached from the substrates. Finally, the free-standing e-sprayed QD/polymer NHB films are successfully applied on top of conventional blue LEDs for remote-type W-LEDs. The W-LED shows the luminous efficacy of 49 lm W-1 and color rendering index (CRI) of 64 with an applied current of 60 mA

Preparation of copper-loaded porous carbons through hydrothermal carbonization and ZnCl2 activation and their application to selective CO adsorption: Experimental and DFT calculation studies

CO is used as a raw material to produce valuable chemicals. Adsorption using solid materials can be employed to separate and recover CO from gas mixtures. In this study, cellulose-based, porous carbons were prepared via hydrothermal carbonization and ZnCl2 activation. The prepared porous carbons were used for CO separation after CuCl loading by a facile solid-state dispersion method to induce ??-complexation and eventually enhance the affinity toward CO. The sample with the highest CO uptake of 3.62 mmol g???1 at 298 K and 101 kPa had a carbon:CuCl loading ratio of 1:1. This is the highest reported CO adsorption on porous carbons using CuCl as a ??-complexation-inducing material. In addition, several factors, including the selectivity of CO against CO2 and the cyclic stability using vacuum regeneration, demonstrated the potential for industrial applications. Density functional theory (DFT) calculations theoretically elucidated that the presence of small and well-dispersed CuCl clusters induce excellent CO-selective adsorption performance, which is in accordance with the experimental results

Solving two environmental issues simultaneously: Waste polyethylene terephthalate plastic bottle-derived microporous carbons for capturing CO2

The treatment of plastic waste is a global issue, and the demand for technologies to reuse or upgrade plastic waste is increasing. In this study, waste polyethylene terephthalate (PET) plastic bottles were used to prepare cost-effective porous carbons, and the prepared carbon materials were tested for capturing CO2. PET plastic bottles were carbonized and activated using KOH or NaOH to develop porous carbons, and their CO2 adsorption behaviors were investigated from both equilibrium and kinetic perspectives. Varying the activation temperature had a significant effect on the textural properties of the prepared carbons. PET-KOH-973, which was prepared by activation with KOH at 973 K, exhibited the highest CO2 uptake of 4.42 mol kg(-1) at 298 K and 101.3 kPa among the tested samples. The experimental adsorption data were well fitted to the Langmuir isotherm and pseudo second-order kinetic models, and the CO2 adsorption on the PET-derived porous carbons was mainly related to the pore volumes of the narrow pores under 0.8 nm in diameter. Grand canonical Monte Carlo simulation and density functional theory calculation were also performed to understand adsorption mechanism and selectivity, and the theoretical calculation agreed well with experimental data. The PET-derived porous carbons exhibited not only high CO2 uptake, but also good selectivity of CO2 over N-2 and CO, simple regeneration, excellent cyclic stability, and fast CO2 adsorption and desorption kinetics

Hf-Doping Effect on the Thermoelectric Transport Properties of n-Type Cu0.01Bi2Te2.7Se0.3

Polycrystalline bulks of Hf-doped Cu0.01Bi2Te2.7Se0.3 are prepared via a conventional melt-solidification process and subsequent spark plasma sintering technology, and their thermoelectric performances are evaluated. To elucidate the effect of Hf-doping on the thermoelectric properties of n-type Cu0.01Bi2Te2.7Se0.3, electronic and thermal transport parameters are estimated from the measured data. An enlarged density-of-states effective mass (from ~0.92 m0 to ~1.24 m0) is obtained due to the band modification, and the power factor is improved by Hf-doping benefitting from the increase in carrier concentration while retaining carrier mobility. Additionally, lattice thermal conductivity is reduced due to the intensified point defect phonon scattering that originated from the mass difference between Bi and Hf. Resultantly, a peak thermoelectric figure of merit zT of 0.83 is obtained at 320 K for Cu0.01Bi1.925Hf0.075Te2.7Se0.3, which is a ~12% enhancement compared to that of the pristine Cu0.01Bi2Te2.7Se0.3

The Role of ZNF143 in Breast Cancer Cell Survival Through the NAD(P)H Quinone Dehydrogenase 1–p53–Beclin1 Axis Under Metabolic Stress

Autophagy is a cellular process that disrupts and uses unnecessary or malfunctioning components for cellular homeostasis. Evidence has shown a role for autophagy in tumor cell survival, but the molecular determinants that define sensitivity against autophagic regulation in cancers are not clear. Importantly, we found that breast cancer cells with low expression levels of a zinc-finger protein, ZNF143 (MCF7 sh-ZNF143), showed better survival than control cells (MCF7 sh-Control) under starvation, which was compromised with chloroquine, an autophagy inhibitor. In addition, there were more autophagic vesicles in MCF7 sh-ZNF143 cells than in MCF7 sh-Control cells, and proteins related with the autophagic process, such as Beclin1, p62, and ATGs, were altered in cells with less ZNF143. ZNF143 knockdown affected the stability of p53, which showed a dependence on MG132, a proteasome inhibitor. Data from proteome profiling in breast cancer cells with less ZNF143 suggest a role of NAD(P)H quinone dehydrogenase 1(NQO1) for p53 stability. Taken together, we showed that a subset of breast cancer cells with low expression of ZNF143 might exhibit better survival via an autophagic process by regulating the p53&#8211;Beclin1 axis, corroborating the necessity of blocking autophagy for the best therapy

Risk of incident mental disorders in hypertrophic cardiomyopathy: a nationwide propensity-matched study

Aims We sought to determine the risk of mental disorders in patients with hypertrophic cardiomyopathy (HCM) compared with those without HCM. Methods and results This is a retrospective propensity score-matched cohort study using nationwide population-based data from the Korean National Health Insurance Service. Overall, 4046 patients with HCM and 12138 matched individuals were followed up until the first diagnosis of mental disorders or the end of the follow up. The primary outcome was a composite of incident mood, anxiety, stress-related, or somatoform disorders. Secondary outcomes included two components of the primary outcome (i.e. mood disorders and anxiety/stress-related/somatoform disorders). During a median follow-up period of 4.1 years, the incidence rate of the primary outcome was 54.4 and 31.5/1000 person-years among the HCM and control groups, respectively, resulting in a hazard ratio (HR) of 1.719 (95% confidence interval: 1.589-1.860). Within the first month after HCM diagnosis, the HR for the primary outcome was 3.074 (2.096-4.508). Beyond 1 month, the HRs decreased, ranging from 2.281 (1.952-2.665) during 1-12 months, to 2.087 (1.831-2.380) during 12-36 months and 1.258 (1.090-1.452) after 36 months of follow up. Similar results were observed for the secondary outcomes. In sensitivity analysis, the risk of the specific categories of mental disorders, including single or recurrent depressive episodes and anxiety disorders, was also higher in patients with HCM than matched controls. Conclusion HCM was significantly associated with the risk of incident mental disorders, particularly within 1 year after HCM diagnosis, underscoring the importance of screening mental health problems, including mood and anxiety disorders, in patients with HCM.N