• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.1-9
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• 1993

In this paper, a new digital mobile channel has been modeled. And concatenated code systems have been proposed to transmit information reliably in the newly modeled mobile fading channels. The BCH code has been used as the outer code and the convolutional code as the inner code. We have modeled the channels which have multipath fading phenomena and additive white Gaussian noise. As a result, the characteristics of the channels are identical to that of the mobile fading channel. To find the best code system, we have tested (7, 4), (63, 45), (63, 57) and (31.26) BCH codes as an outer code. Results show that the concatenated code with (7, 4) outer code gives the best performance. And if we use the soft decision, we can improve about 2 -6 dB in the SNR

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.959-966
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• 2015

In this paper, we propose an indoor visible light communication(VLC) localization using Walsh code which can identify overlapped signals transmitted from the different LED sources as each of orthogonal signal at a receiver and using Manchester code which can eliminate the flicker of LED light and maintain a constant brightness. The proposed system can estimate the relative position of the receiver by using Lambertian radiation properties and trilateration method that are applied to the location information of fixed LED sources and the received signals from them. In order to verify the feasibility of the proposed system, we carried out the simulation in an indoor space with $6{\times}6{\times}1.5m^3$ installed LED lamps of 16. The simulation result shows that the proposed method achieves an average positioning error of 0.0536 m and a maximum positioning error of 0.2977 m.

• Journal of Internet Computing and Services
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• v.19 no.3
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• pp.15-23
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• 2018

A code reuse attack is an attack technique that can execute arbitrary code without injecting code directly into the stack by combining executable code fragments existing in program memory and executing them continuously. ROP(Return-Oriented Programming) attack is typical type of code reuse attack and serveral defense techniques have been proposed to deal with this. However, since existing methods use Rule-based method to detect attacks based on specific rules, there is a limitation that ROP attacks that do not correspond to previously defined rules can not be detected. In this paper, we introduce a method to detect ROP attack by learning command pattern used in ROP attack code using RNN(Recurrent Neural Network). We also show that the proposed method effectively detects ROP attacks by measuring False Positive Ratio, False Negative Ratio, and Accuracy for normal code and ROP attack code discrimination.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.279-285
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• 2011

The next generation wireless communication systems are required high BER performance better than present performance. Double binary Turbo code have error floor at high SNR, so it cannot be used in next generation wireless communication system. Therefore, many methods are proposed for overcome error floor at DVB-RCS NG(next generation). In this paper, we analysis structure of third-dimension Turbo code(3D-turbo code). 3D-Turbo code overcomes error flow by additive post-encoder in conventional DVB-RCS Turbo code. Performance of 3D-Turbo code is changed by post-encoder form, interleaving method, value of ${\lambda}$. So we are simulated by those parameter and proposed optimal form. By a result, performance of 3D-Turbo is better than conventional DVB-RCS Turbo code and it overcome error floor of conventional DVB-RCS Turbo code.

• Smart Media Journal
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• v.2 no.3
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• pp.39-46
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• 2013

According to popularization of smart phones, we can easily see the QR code attached to products. Restaurants also provide customers with store information using QR code. Sixteen years have passed since QR code was developed. In Korea, QR code has been widely utilized in the field of marketing because of easiness of technique implementation and channel expansion to mobile. However, to recognize QR code, we should run the proper application and focus on it during loading time. To address this problem, this paper proposes the app to manage store information using NFC technology. The proposed app saves easily store information through the name card of a store and facilitates its management obtained by a smart phone.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.99-117
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• 2006

Consumers keep demanding for diversified high quality products, valuable services and safety. With this in mind, Distribution Industry is being updated rapidly to accomodate this demand. Meanwhile, Distribution Information Technology of agricultural products has been in slow progress with little in-depth studies. In this study, it has been analyzed the usage of Bar code which is the key element for agricultural Distribution Information Technology. The analysis was conducted through a survey utilizing questionnaire covering 5 Hypermarkets(Super-centers) including big 3 companies. Also, Japanese market trends have been studied to visit a Japan Government Organization concerned, GS1 Japan, an Agricultural Cooperative, an Agricultural Wholesale Market, and a Retail Company. If we could use KAN code for all agricultural products, we could collect and analyze the information of price and trade quantity of them. It opens a new era to understand the agricultural products supply and demand easily. This will certainly make a great contribution to the evolution of agricultural products distribution. From this research, it is suggested that collective efforts by suppliers, wholesalers, retailers and Government Officers are needed to make large scale mutual marketing Organizations, which specialize in sending out agricultural products. The Organization is recommended to standardize and pack every final agricultural products, to promote the use of KAN code.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.4
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• pp.511-517
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• 1998

In this paper a new technique to generate spreading code sequences in the CDMA communication is introduced. It is an effective method to generate optimal code sequences using the orthogonality of wavelet packet basis set of subspaces. With a three-stage Quadrature Mirror Filter(QMF), generation of optimal code sequences has been demonstrated. Since these generated optimal code sequences are non-binary and have an arbitrary waveform which is different from that of the conventional PN-based Gold code sequences, a strong security against the intended interceptor is feasible. Encouraging good correlation properties are also achieved with this new method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1302-1310
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• 1997

In this paper, we propose a dynamic code allocation strategy using voice activity detection and evaluate the performance of a dynamic code allocation strategy using voice activeity detection in DS-CDMA system. Proposed method allocates code to mobile terminal according to the residual capacity computed by SIR in the base station. In hot spot traffic loading cell, we find that the performance of proposed method is better than that of a fixed code assignment strategy using voice activity detection. Also, we find that the proposed method provide much improvement in blocking probability against the dynamic code assignment strategy withoug voice activity detection.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1541-1544
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• 2001

Java virtual machine의 성능을 향상시키기 위해 "JIT(Just-in-Time)"code generator가 고안되었다[3], JIT code generator는 스택기반의 자바 바이트 코드를 레지스터 기반의 native machine code로 변환해 주는 역할을 수행하여 바이트 코드의 번역시간을 줄여준다. 그러나 JIT 는 많은 레지스터의 사용을 야기시키므로 효율적인 레지스터 allocation 정책이 필요하고 스택과 레지스터 간의 traffic 을 가중시킨다. 그러므로 본 논문에서는 자바 바이트 코드의 효율적인 stack allocation 정책을 JIT code generator에 적용함으로 레지스터와의 traffic을 줄이는 방법을 제시하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.633-636
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• 2017

This paper presents a cloud service called CDLint for checking and analyzing the Javascript code dynamically. The correctness of Javascript code is becoming more important since it can also run on the server side as well as the client side. There are several analysis systems for checking the bad code in JavaScript but they seem like have one or more weaknesses. CDLint is developed based on an existing work named DLint which is a powerful bad JavaScript checker. Compared with similar systems, CDLint shows the best performances with respect to the system extensibility, the freedom to use without installation, the automatic parsing of JavaScript code from website, and the environment configuration for JavaScript code checking.