• Journal of KIISE:Computing Practices and Letters
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• v.16 no.8
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• pp.873-877
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• 2010

CAPTCHA is a security tool that prevents the automatic sign-up by a spam or a robot. This CAPTCHA usually depends on the smart readability of humans. However, the common and plain CAPTCHA with text-based system is not difficult to be solved by intelligent web-bot and machine learning tools. In this paper, we propose a new sub-image based CAPTCHA system totally different from the text based system. Our system offers a set of cropped sub-image from a whole digital picture and asks user to identify the correct orientation. Though there are some nice machine learning tools for this job, but they are useless for a cropped sub-images, which was clearly revealed by our experiment. Experiment showed that our sub-image based CAPTCHA is easy to human solver, but very hard to all kinds of machine learning or AI tools. Also our CAPTCHA is easy to be generated automatical without any human intervention.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.470-485
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• 2003

The steganography is one of methods that users can hide data. Some steganography softwares use audio data among multimedia data. However, these commercialized audio steganography softwares have disadvantages that the existence of hidden messages can or easily recognized visually and only certain-sized data can be hidden. To solve these problems, this study suggested, designed and implemented Dynamic Message Embedding (DME) algorithm. Also, to improve the security level of the secret message, the file encryption algorithm has been applied. Through these, StegoWaveK system that performs audio steganography was designed and implemented. Then, the suggested system and the commercialized audio steganography system were compared and analyzed on criteria of the Human Visilable System (HVS), Human Auditory System (HAS), Statistical Analysis (SA), and Audio Measurement (AM).

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.625-630
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• 2016

This paper contributes to the development of an early detection system to detect the alteration of a target ship during early stages using the steering wheel signal via AIS communication. The feasibility of this system is also verified with a real ship trial. It was confirmed that the rudder angle on ECDIS was ordinarily marked green or red by the used rudder angle after the steering wheel operation. We were able to detect intentions for a change in course by a target ship quickly and efficiently avoid collisions. This system will contribute to more active VTS services and the analysis of marine accidents using the General Information Center On Maritime Safety & Security (GICOMS).

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.792-797
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• 2015

Effective profiling diagnoses the failure of the system and informs risk. If a failure in the target system occurs, it is impossible to diagnose more than one of the exiting tools. In this respect, monitoring of the system based on virtualization is useful. We present in this paper a monitoring framework that uses the characteristics of hardware virtualization to prevent side-effects from a target guest, and uses dynamic binary instrumentation with instruction-level trapping based on hardware virtualization to achieve efficiency and flexibility. We also present examples of some applications that use this framework. The framework provides tracing of guest kernel function, memory dump, and debugging that uses GDB stub with GDB remote protocol. The experimental evaluation of our prototype shows that the monitoring framework incurs at most 2% write memory performance overhead for end users.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.327-331
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• 2004

The new cyber world has created by Internet that is prosperous rapidly. But with the expansion of Internet the hacking and intrusion are also increased very much. Actually there were many incidents in Internet, but the damage was restricted within a local area and local system. However, the Great 1.25 Internet Disturbance has paralyzed the national wide Internet environment. It because the Slammer Worm. The worm is a malformed program that uses both of the hacking and computer virus techniques. It autonomously attacks the vulnerability of Windows system, duplicates and spreads by itself. Jus like the Slammer Worm, almost every worms attack the vulnerability of Windows systems that installed in personal PC. Therefore, the vulnerability in personal PC could destroy the whole Internet world. So, in this paper we propose a Internet Worm Expanding Prevention System that could be installed in personal PC to prevent from expanding the Internet Worm. And we will introduce the results of developed system.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.291-301
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• 2018

The purpose of this study is to investigate the factors that affect the perceived awareness and the intention of continuous use by FinTech users and system characteristics. Data collection was carried out by targeting and surveying 600 people living in Gwangju, and office workers using smartphones. As a result, first, self-efficacy, innovation, and fitness for Fin-Tech services were found to influence the degree of perceptual awareness and intent to use of Fin-tech service users. Second, the system characteristics have a positive effect on perceived awareness and intention of using FinTech service. Third, the hypothesis about the dangers in the user attributes and system properties were dismissed. It seems that the priority concern was regarding the leakage of personal information and security as privacy and the increasing damage cases of financial fraud by electronic financial transactions spill. Therefore, in order to spread FinTech services, it would be effective if a Fin-Tech service strategy could eliminate inconveniences such as the risk of hindering convenience and intention to use by the marketing strategy established by the company.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.400-407
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• 2003

In this paper an optical encryption system, which can decrypt the original image by using the autocorrelation terms of a JTC, is proposed. Unlike the classical JTC, the joint input plane of the proposed system is composed in a frequency domain not a spatial domain, thus it needs only one Fourier transformation. To use like this, the phase component appeared in the output plane of JTC should be considered. We presents the effect of phase and provides the solution. An original image is encrypted to a complex-valued random image. The original image is reconstructed using the autocorrelation terms which is the main drawback of JTC, therefore the proposed system is more suitable for JTC and real time processing. By computer simulation and optical experiment, the analysis for the phase effect and the performance of the proposed system are confirmed.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.33-42
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• 2011

In this paper we designed and implemented a wireless communication circuit which can control the remote devices integrating RFID and ZigBee. This system unifies transmit part and receive part. And this system recognizes RFID tag data, then the recognized information is controlled by MCU, and transmitted to a remote device through the ZigBee. This is operated on TinyOS. If this system is applied to a entrance security system, it can permit/deny one's entrance as well as control the personal computer or other electronic devices. Our experiment shows the result of the recognized data transmission is very different according to a opened playground and a closed place. The data transmission time is stable in the indoor and the data transmission distance is long in the outdoor. We anticipate that our system be applied the various office oriented domains by connecting to the Wired LAN or the WLAN of IEEE 802.11x category.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.101-112
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• 2010

The recent trend of the hacking deals with all the IT infrastructure related to the profit of the companies. Presently, they attack the service itself, the source of the profit, while they tried to access to the service infrastructure through the non-service port in the past. Although they affect the service directly, it is difficult to block them with the old security solution or the old system and they threaten more and more companies with the demand of money menacing the protection of customers and the sustainable management. This paper aims to design and implement multi-platform network packet scanner targeting the exception handling network intrusion detection system which determines normal, abnormal by traffic. Linux and unix have the various network intrusion detection and packet management tools like ngrep, snort, TCPdump, but most of them are based on CUI (Character based User Interface) giving users discomfort who are not used to it. The proposed system is implemented based on GUI(Graphical User Interface) to support the intuitive and easy-to-use interface to users, and using Qt(c++) language that supports multi-platform to run on any operating system.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.47
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• pp.185-212
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• 2010

This study aims to derive practical suggestions to apply application methods by auxiliary costs, especially application of logistics and customs clearance areas in order to establish EPS support system of auxiliary cost occurred from export/import. For the propose, this study has analyzed types and situation of auxiliary costs, application method by auxiliary costs, payment situation of logistics auxiliary costs and clearance auxiliary costs and suggested the relevant problems and their application methods. Especially, in case of logistics auxiliary costs through connection to the attached general documents required for negotiation by reflecting characteristics of B2B transactions. In addition, it has suggested that those services by the said system should be conveniently used commonly by the export companies and logistics companies through provision of various payment measures, support of foreign currency payment, etc. and security of reliability/system stability, etc. for the compatible payment with other systems as the prerequisite for the successful settlement of the auxiliary costs EPS. It is expected that satisfaction of the uTradeHub users such as export/import companies and logistics companies will be increased, user-oriented customized information services such as raw cost prediction service through calculation of auxiliary costs could be available in the future and efficiency of work processes related to auxiliary costs will be increased, by providing the EPS through various single window based payment measures through establishment of the export/import auxiliary costs payment system.