• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.59-67
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• 2012

It was reported that the latest sensor technology allow an 65536 conductive polymer sensor array to be made with broad but overlapping selectivity to different families of chemicals emulating the characteristics found in biological olfaction. However, the supernumerary redundancy always accompanies great error and risk as well as an inordinate amount of computation time and local minima in signal processing, e.g. neural networks. In this paper, we propose a new method to reduce the number of sensor for analysis by reducing redundancy between sensors and by removing unstable sensors using the cosine similarity method and to decide on representative sensor using FCM(Fuzzy C-Means) algorithm. The representative sensors can be just used in analyzing. And, we introduce DWT(Discrete Wavelet Transform) for data compression in the time domain as preprocessing. Throughout experimental trials, we have done a comparative analysis between gas sensor data with and without reduced redundancy. The possibility and superiority of the proposed methods are confirmed through experiments.

• Journal of Sensor Science and Technology
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• v.22 no.2
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• pp.162-173
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• 2013

The purpose of this paper is to classify VOC gases by emulating the characteristics found in biological olfaction. For this purpose, we propose new signal processing method based a polymeric chemical sensor array consisting of 4096 sensors which is created by NEUROCHEM project. To remove unstable sensors generated in the manufacturing process of very large scaled chemical sensor array, we used discrete wavelet transformation and cosine similarity. And, to remove the supernumerary redundancy, we proposed the method of selecting candidates of representative sensor representing sensors with similar features by Fuzzy c-means algorithm. In addition, we proposed an improved algorithm for selecting representative sensors among candidates of representative sensors to better enhance classification ability. However, Classification for very large scaled sensor array has a great deal of time in process of learning because many sensors are used for learning though a redundancy is removed. Throughout experimental trials for classification, we confirmed the proposed method have an outstanding classification ability, at transient state as well as steady state.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.11-18
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• 2013

In this paper, we propose a new design scheme of N-Screen emulator based on Cloud and then implement the emulator, in order to solve the critical point of N-Screen emulator based on Cloud. This method, without the emulator in the server, will be able to confirm the features of the emulator with a browser using Web Service. This means that the identical service is possible without regard to personal computer or mobile environment. Also, in order to emulating each different web browser engine of the various devices separately, we revise and manage the WebKit engine to be suitable to the characteristics of each device. In the previous design method, the number of emulators which can be shown in a monitor is restricted to 2 or 3. However, we show that the proposed design method can improve the performance of server to the extent that this method could operate more than 100 emulators per each server.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.57-63
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• 2008

As diverse memory cards based on NAND flash memory are getting popularity with consumer electronics such as digital camera, camcorder and MP3 player the compatibility problems between a newly developed memory card and existent host systems have become a main obstacle to time-to-market delivery of product. The common practice for memory card compatibility test is to use a real host system as a test bed. As an improved solution, an FPGA-based prototyping board can be used for emulating host systems. However, the above approaches require a long set-up time and have limitations in representing various host and device systems. In this paper, we propose a co-validation environment for compatibility test between memory card and host system using formal modeling based on Esterel language and co-simulation methodology. Finally, we demonstrate the usefulness of the proposed environment with a case study of real memory card development.

• Journal of the Korean Geotechnical Society
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• v.27 no.11
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• pp.55-69
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• 2011

The importance of unsaturated state in various geo-engineering problems has led to the advance of mechanical constitutive model emulating behavior of unsaturated soils in response to thermo-hydro-mechanical loading. Elasto-plastic mechanical constitutive model for unsaturated soil is formulated based on Bishop's effective stress. Effective stress and temperature are main variables in constitutive equation, and incremental formulation of constitutive relationship is derived to compute stress update and stiffness tensor. Numerical simulations involving coupled THM processes are conducted to discuss numerical stability and applicability of developed constitutive model: one-dimensional test, tri-axial compression test, and clay-buffering at high level radioactive waste disposal. Numerical results demonstrated that developed model can predict very complex behavior of coupled THM phenomena and is applicable to geo-engineering problems under various environmental conditions, as well as interpret typical behavior of unsaturated soils.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1225-1234
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• 2019

The security of the firmware is more important because embedded devices have become popular. Network devices such as routers can be attacked by attackers through web application vulnerabilities in embedded firmware. Therefore, they must be found and removed quickly. The Firmadyne framework proposes a dynamic analysis method to find vulnerabilities after emulating firmware. However, it only performs vulnerability checks according to the analysis methods defined in the tool, thus limiting the scope of vulnerabilities that can be found. In this paper, fuzzing is performed in emulation-based environment through fuzzing, one of the software security test techniques. We also propose a Fabfuzz tool for efficient emulation based fuzzing. Experiments have shown that in addition to the vulnerabilities identified in existing tools, other types of vulnerabilities have been found.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.95-105
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• 2002

This paper describes an efficient method to implement a hardware circuit of RSA public key cryptographic algorithm, which is important to public-key cryptographic system for an authentication, a key exchange and a digital signature. The RSA algorithm needs a modular exponential for its cryptographic operation, and the modular exponential operation is consists of repeated modular multiplication. In a numerous algorithm to compute a modular multiplication, the Montgomery algorithm is one of the most widely used algorithms for its conspicuous efficiency on hardware implementation. Over the past a few decades a considerable number of studies have been conducted on the efficient hardware design of modular multiplication for RSA cryptographic system. But many of those studies focused on the decrease of operating time for its higher performance. The most important thing to design a hardware circuit, which has a limit on a circuit area, is a trade off between a small circuit area and a feasible operating time. For these reasons, we modified the Montgomery algorithm for its efficient hardware structure for a system having a limit in its circuit area and implemented the refined algorithm in the IESA system developed for ETRI's smart card emulating system.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.390-399
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• 2022

Cyber security and resilience are phrases that describe safeguards of ICTs (information and communication technologies) from cyber-attacks or mitigations of cyber event impacts. The sole purpose of Risk models are detections, analyses, and handling by considering all relevant perceptions of risks. The current research effort has resulted in the development of a new paradigm for safeguarding services offered online which can be utilized by both service providers and users. customers. However, rather of relying on detailed studies, this approach emphasizes task selection and execution that leads to successful risk treatment outcomes. Modelling intelligent CSGs (Cyber Security Games) using MLTs (machine learning techniques) was the focus of this research. By limiting mission risk, CSGs maximize ability of systems to operate unhindered in cyber environments. The suggested framework's main components are the Threat and Risk models. These models are tailored to meet the special characteristics of online services as well as the cyberspace environment. A risk management procedure is included in the framework. Risk scores are computed by combining probabilities of successful attacks with findings of impact models that predict cyber catastrophe consequences. To assess successful attacks, models emulating defense against threats can be used in topologies. CSGs consider widespread interconnectivity of cyber systems which forces defending all multi-step attack paths. In contrast, attackers just need one of the paths to succeed. CSGs are game-theoretic methods for identifying defense measures and reducing risks for systems and probe for maximum cyber risks using game formulations (MiniMax). To detect the impacts, the attacker player creates an attack tree for each state of the game using a modified Extreme Gradient Boosting Decision Tree (that sees numerous compromises ahead). Based on the findings, the proposed model has a high level of security for the web sources used in the experiment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.253-266
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• 2023

The Null Pointer Dereference vulnerability is a significant vulnerability that can cause severe attacks such as denial-of-service. Previous research has proposed methods for detecting vulnerabilities, but large and complex programs pose a challenge to their efficiency. In this paper, we present a lightweight tool for detecting specific functions in large binaryprograms through symbolizing variables and emulating program execution. The tool detects vulnerabilities through data dependency analysis and heuristics in each execution path. While our tool had an 8% higher false positive rate than the bap_toolkit, it detected all existing vulnerabilities in our dataset.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.5
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• pp.721-736
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• 2023

The Command and Control Framework was developed for penetration testing and education purposes, but threat actors such as cybercrime groups are abusing it. From a cyber threat hunting perspective, identifying Command and Control Framework servers as well as proactive responding such as blocking the server can contribute to risk management. Therefore, this paper proposes a methodology for tracking the Command and Control Framework in advance. The methodology consists of four steps: collecting a list of Command and Control Framework-related server, emulating staged delivery, extracting botnet configurations, and collecting certificates that feature is going to be extracted. Additionally, experiments are conducted by applying the proposed methodology to Cobalt Strike, a commercial Command and Control Framework. Collected beacons and certificate from the experiments are shared to establish a cyber threat response basis that could be caused from the Command and Control Framework.