Kyu Hyoung Lee 교수

System-level audit logs capture the interactions between applications and the runtime environment. They are highly valuable for forensic analysis that aims to identify the root cause of an attack, which may occur long ago, or to determine the ramifications of an attack for recovery from it. A key challenge of audit log-based forensics in practice is the sheer size of the log files generated, which could grow at a rate of Gigabytes per day. In this paper, we propose LogGC, an audit logging system

An important aspect of cyber attack forensics is to understand the provenance of suspicious events, as it discloses the root cause and ramifications of cyber attacks. Traditionally, this is done by analyzing audit log. However, the presence of long running programs makes a live process receiving a large volume of inputs and produce many outputs and each output may be causally related to all the preceding inputs, leading to dependence explosion and making attack investigations almost infeasible.

Abstract Band engineering is an effective strategy to improve the electronic transport properties of semiconductors. In thermoelectric materials research, density‐of‐states effective mass is an undoubted key factor in verifying the band engineering effect and establishing a strategy for enhancing thermoelectric performance. However, estimation of the effective mass is demanding or inaccurate depending on the methods taken. A simple equation is proposed, valid for all degeneracy: Log 10 ( m d * T

A class of materials known as superlattices has shown substantial promise for potential thermoelectric (TE) applications because of its low thermal conductivity. We have investigated natural superlattice Ruddlesden-Popper (RP) phases [S. N. Ruddlesden and P. Popper, Acta Crystallogr. 10, 538 (1957)] to elucidate their potential as TE materials. The TE properties of Nb-doped SrO(SrTiO3)n (n=1,2) with a RP structure were measured, and the origin of the TE properties is discussed from the viewpoint

Herein, we report on a scalable synthesis of Au nanodot (Au-ND)/Bi₂Te₃ nanotube (BT-NT) nanocomposites by the bottom-up synthesis of hybrid raw materials and subsequent spark plasma sintering, and their thermoelectric properties were systematically compared with those of Au-doped Bi₂Te₃ compounds.

A dual catalyst containing Pd and CuFe(2)O(4) nanoparticles in a silica shell exhibits >98% conversion of arylacetylenes to related styrenes with selectivity greater than 98%, which are better than those obtained using a commercial Lindlar catalyst. The excellent synergy was likely a result of the proximal interaction between Pd and CuFe(2)O(4) nanoparticles.

Traditional auditing techniques generate large and inaccurate causal graphs. To overcome such limitations, researchers proposed to leverage execution partitioning to improve analysis granularity and hence precision. However , these techniques rely on a low level programming paradigm (i.e., event handling loops) to partition execution , which often results in low level graphs with a lot of redundancy. This not only leads to space inefficiency and noises in causal graphs, but also makes it difficu

Abstract Taming electronic and thermal transport properties is the ultimate goal in the quest to achieve unprecedentedly high performance in thermoelectric (TE) materials. Most state‐of‐the‐art TE materials are inherently narrow bandgap semiconductors, which have an inevitable contribution from minority carriers, concurrently decreasing Seebeck coefficient and increasing thermal conductivity. Nevertheless, the restraint control of minority carrier transport is seldom considered as a key element

We herein report the significantly improved thermoelectric performance of n-type Bi₂Te_2.7Se_0.3 polycrystalline bulks through band structure engineering achieved by Au-doping.