Sehun Kim

Bio: Sehun Kim is an academic researcher from KAIST. The author has contributed to research in topics: Intrusion detection system & Scanning tunneling microscope. The author has an hindex of 22, co-authored 74 publications receiving 1954 citations.

A novel hybrid intrusion detection method integrating anomaly detection with misuse detection

Abstract: In this paper, a new hybrid intrusion detection method that hierarchically integrates a misuse detection model and an anomaly detection model in a decomposition structure is proposed. First, a misuse detection model is built based on the C4.5 decision tree algorithm and then the normal training data is decomposed into smaller subsets using the model. Next, multiple one-class SVM models are created for the decomposed subsets. As a result, each anomaly detection model does not only use the known attack information indirectly, but also builds the profiles of normal behavior very precisely. The proposed hybrid intrusion detection method was evaluated by conducting experiments with the NSL-KDD data set, which is a modified version of well-known KDD Cup 99 data set. The experimental results demonstrate that the proposed method is better than the conventional methods in terms of the detection rate for both unknown and known attacks while it maintains a low false positive rate. In addition, the proposed method significantly reduces the high time complexity of the training and testing processes. Experimentally, the training and testing time of the anomaly detection model is shown to be only 50% and 60%, respectively, of the time required for the conventional models.

DDoS attack detection method using cluster analysis

Abstract: Distributed Denial of Service (DDoS) attacks generate enormous packets by a large number of agents and can easily exhaust the computing and communication resources of a victim within a short period of time. In this paper, we propose a method for proactive detection of DDoS attack by exploiting its architecture which consists of the selection of handlers and agents, the communication and compromise, and attack. We look into the procedures of DDoS attack and then select variables based on these features. After that, we perform cluster analysis for proactive detection of the attack. We experiment with 2000 DARPA Intrusion Detection Scenario Specific Data Set in order to evaluate our method. The results show that each phase of the attack scenario is partitioned well and we can detect precursors of DDoS attack as well as the attack itself.

Covalent Functionalization of Epitaxial Graphene by Azidotrimethylsilane

Abstract: Chemically modified epitaxial graphene (EG) by azidotrimethylsilane (ATS) was investigated using high-resolution photoemission spectroscopy (HRPES). Through the spectral analysis, we clearly confirmed that EG is modified by thermally generated nitrene radicals and found that the bonding nature between the nitrene radicals and EG is covalent. As we observe bonding nature of N 1s peaks, we found that two distinct N peaks can be clearly distinguished in the spectra. Using a covalently bound stretched graphene (CSG) model, we elucidated that nitrene radicals adsorb on the graphene layer at two different adsorption sites. Moreover, we were able to control the band gap of EG using valence band spectra as we change the amount of the dosing of nitrene.

A two-phase algorithm for frequency assignment in cellular mobile systems

Abstract: In this paper, we consider the frequency assignment problem (FAP) in a cellular mobile communication system under the assumption that there is no channel interference between two cells separated by more than a certain distance. This special structure is observed in most cellular systems. To handle the considered FAP, we use the pattern approach which fits naturally to the problem. Based on this approach, we are able to formulate the considered FAP into a manageable optimization problem and propose a two-phase heuristic algorithm for the problem. Computational experiments show that our algorithm performs much better in both solution quality and computational time than the recently developed algorithms for FAP. Since the considered FAP well reflects most cellular systems, our algorithm can be applied to many practical situations. >

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Abstract: Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Reality mining: sensing complex social systems

Abstract: We introduce a system for sensing complex social systems with data collected from 100 mobile phones over the course of 9 months. We demonstrate the ability to use standard Bluetooth-enabled mobile telephones to measure information access and use in different contexts, recognize social patterns in daily user activity, infer relationships, identify socially significant locations, and model organizational rhythms.

The Self-Organizing Map

Abstract: An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

Graphene-Based Materials: Synthesis, Characterization, Properties, and Applications

Abstract: Graphene, a two-dimensional, single-layer sheet of sp(2) hybridized carbon atoms, has attracted tremendous attention and research interest, owing to its exceptional physical properties, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Other forms of graphene-related materials, including graphene oxide, reduced graphene oxide, and exfoliated graphite, have been reliably produced in large scale. The promising properties together with the ease of processibility and functionalization make graphene-based materials ideal candidates for incorporation into a variety of functional materials. Importantly, graphene and its derivatives have been explored in a wide range of applications, such as electronic and photonic devices, clean energy, and sensors. In this review, after a general introduction to graphene and its derivatives, the synthesis, characterization, properties, and applications of graphene-based materials are discussed.

[서평]「Applied Cryptography」

Abstract: The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.