김주환 교수

Activated carbon (AC) is used in commercial electric double-layer capacitors (EDLC) as electrode active material owing to its favorable properties. However, oxygen functional groups (OFGs) present in AC reduce the lifespan of EDLCs. Thus, we investigated the correlation between the OFGs in AC and their electrochemical characteristics. Samples were prepared by heat-treating commercial AC at 300 °C-900 °C for 1 h under two gas atmospheres (N₂ and 4% H₂/N₂ mixed gas

This study presents the first investigation of cellulose-based activated carbon fibers (RACFs) prepared as electrode materials for the electric double-layer capacitor (EDLC) in lieu of activated carbon, to determine its efficacy as a low-cost, environmentally friendly enhancement alternative to nanocarbon materials. The RACFs were prepared by steam activation and their textural properties were studied by Brunauer-Emmett-Teller and non-localized density functional theory equations with N<sub>2</s

Demand for hybrid energy storage systems is growing, but electric double-layer capacitors (EDLCs) have insufficient output characteristics because of the microporous structure of the activated carbon electrode material. Commercially, activated carbon is prepared from coconut shells, which yield an activated carbon material (YP-50F) rich in micropores, whereas mesopores are desired in EDLCs. In this study, we prepared mesoporous activated carbon (PB-AC) using a readily available, environmentally

With the growing prevalence of the Internet of Things (IoT), related security threats have kept pace. The need to dynamically detect vulnerabilities in IoT devices cannot be overstated. In this work, we present FIRM-COV, the first high coverage-oriented greybox fuzzer for IoT firmware. FIRM-COV leverages newly optimized process emulation by targeting IoT programs and mining real-world vulnerabilities. FIRM-COV focuses on solving problems of IoT fuzzing based on empirical analyses, using the requ

Hybrid fuzzers combine both fuzzing and concolic execution with the wish that the fuzzer will quickly explore input spaces and the concolic execution will solve the complex path conditions. However, existing hybrid fuzzers such as Driller cannot be effectively directed, for instance, towards unsafe system calls or suspicious locations, or towards functions in the call stack of a reported vulnerability that we wish to reproduce. In this poster, we propose DrillerGO, a directed hybrid fuzzing syst

Sonar sensors are widely utilized underwater because they can observe long-ranged objects and are tolerant to measurement conditions, such as turbidity and light conditions. However, sonar images have low quality and hard to collect, so development and application of sonar-based algorithms are difficult. This paper proposes a method to generate realistic sonar images or to segment real sonar image, to better utilize the sonar sensors. A simple sonar image simulator was implemented using a ray-tr

This study used a physical activation method to prepare asphalt-pitch-derived activated carbon (Pitch AC) for an electric double-layer capacitor (EDLC) electrode. X-ray diffraction analysis and Raman spectroscopy were used to estimate the change in the crystal structure of Pitch AC with activation time. In addition, the textural properties of Pitch AC were studied by Brunauer-Emmett-Teller (BET), Dubinin-Radushkevich (DR) and non-localized density functional theory (NLDFT) equations with N2/77K

Virtual reality and augmented reality are increasingly used for immersive engagement by utilizing information from real environments. In particular, three-dimensional model data, which is the basis for creating virtual places, can be manually developed using commercial modeling toolkits, but with the advancement of sensing technology, computer vision technology can also be used to create virtual environments. Specifically, a 3D reconstruction approach can generate a single 3D model from image in