• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.796-804
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• 2010

It is important to use the comb type pilot allocation for the continuous channel and efficient processing. And DFT-spreading OFDM is used a lot to solve high PAPR problem of OFDM system. However, PAPR is increased again when comb type pilot is used to estimate channel characteristics. So, in this paper, we employ a new SLM method to DFT-spreading OFDM system to reduce increased high PAPR. And we suggest an effective method to transmit side information without additional bandwidth. Pilot and side information must be preserved from jamming or intentional interferences since those are very important in DFT spread OFDM system using SLM. So, in this paper, we like to analyze and simulate the performance of DFT spread OFDM system based on SLM against jamming signal. To remedy the vulnerable shortcomings of DFT spread OFDM about jamming or intentional interferences, we employ FH(Frequency Hopping) method and analyze system performance under the several jamming conditions such as MTJ(Multi Tone Jamming) and PBJ(Partial Band Jamming).

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1153-1166
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• 2011

Detecting misbehavior in vehicular ad-hoc networks is very important problem with wide range of implications including safety related and congestion avoidance applications. Most misbehavior detection schemes are concerned with detection of malicious nodes. In most situations, vehicles would send wrong information because of selfish reasons of their owners. Because of rational behavior, it is more important to detect false information than to identify misbehaving nodes. In this paper, we propose the variable precision rough sets based misbehavior detection scheme which detects false alert message and misbehaving nodes by observing their action after sending out the alert messages. In the proposed scheme, the alert information system, alert profile is constructed from valid actions of moving nodes in vehicular ad-hoc networks. Once a moving vehicle receives an alert message from another vehicle, it finds out the alert type from the alert message. When the vehicle later receives a beacon from alert raised vehicle after an elapse of time, then it computes the relative classification error by using variable precision rough sets from the alert information system. If the relative classification error is lager than the maximum allowable relative classification error of the alert type, the vehicle decides the message as false alert message. Th performance of the proposed scheme is evaluated as two metrics: correct ratio and incorrect ratio through a simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.440-446
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• 2016

Military secrets or confidential data of any organization are extremely important assets. They must be discluded from outside. To do this, methods for detecting anomalous attacks and intrusions inside the network have been proposed. However, most anomaly-detection methods only cover aspects of intrusion from outside and do not deal with internal leakage of data, inflicting greater damage than intrusions and attacks from outside. In addition, applying conventional anomaly-detection methods to data exfiltration creates many problems, because the methods do not consider a number of variables or the internal network environment. In this paper, we describe issues considered in data exfiltration detection for anomaly detection (DEDfAD) to improve the accuracy of the methods, classify the methods as profile-based detection or machine learning-based detection, and analyze their advantages and disadvantages. We also suggest future research challenges through comparative analysis of the issues with classification of the detection methods.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.19-33
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• 2012

Ministry of Land, Transport and Maritime Affairs prepared the method to update traffic connection system by amending "National Transport System Efficiency Act(hereinafter Act)". The key is a development of Intermodal Transfer Center. The law and guideline related with Intermodal Transfer Center requires the installation and operation of transfer information guide facility to improve user's convenience. However, there are no sufficient studies that can be used as references for the method to construct transfer support information system related with user's preference. The study performed the research about user's service satisfaction in relation with transfer support information service, which was embodied in model operation process, on the basis of transfer support information system of Intermodal Transfer Center applied to Gimpo Airport. The analysis result about service preference, importance of each supplied information, service satisfaction and consideration for service embodiment can be used as a guideline to embody the user information service of Intermodal Transfer Center. In addition, through CVM, the study estimated and proposed the service valuation of smart intermodal transfer service that provides customized information to cope with user's situation and traffic means operation status among transfer support information service. It is determined that the study will measure the benefit of Intermodal Transfer Center user by using monetary value when smart intermodal transfer service is supplied and provide the ground to expand high-tech transfer information service with high usefulness and convenience.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.10
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• pp.391-398
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• 2021

Since the leased line is a structure that exclusively uses two connected areas for data transmission, a stable quality level and security are ensured, and despite the rapid increase in the number of switched lines, it is a line method that is continuously used a lot in companies. However, because the cost is relatively high, one of the important roles of the network operator in the enterprise is to maintain the optimal state by properly arranging and utilizing the resources of the network leased line. In other words, in order to properly support business service requirements, it is essential to properly manage bandwidth resources of leased lines from the viewpoint of data transmission, and properly predicting and managing leased line usage becomes a key factor. Therefore, in this study, various prediction models were applied and performance was evaluated based on the actual usage rate data of leased lines used in corporate networks. In general, the performance of each prediction was measured and compared by applying the smoothing model and ARIMA model, which are widely used as statistical methods, and the representative models of deep learning based on artificial neural networks, which are being studied a lot these days. In addition, based on the experimental results, we proposed the items to be considered in order for each model to achieve good performance for prediction from the viewpoint of effective operation of leased line resources.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.1-10
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• 2019

In terms of realizing the future e-government such as intelligent government, this paper attempts to provide an earnest and insightful reflection and suggests desirable strategies with regard to the four different crucial elements including electronic voting, electronic contract, resident registration/electronic document management, and real-estate registration as an operating strategy of intelligent government and the fourth industrial revolution regarding. The 4th industrial revolution is aimed at concentrating information or data characterized with sharing, opening, communicating and releasing in cloud computing system, analyzing big data, collecting information, and flourishing people's well-being by information and communications technology with utilizing the smart devices. Therefore, reliability of the pivotal information or data is critical and it is important for the participants being transparently shared, without the data or information being forged. In this respect, introduction or application of block chain technology is essential. This paper will review preceding studies, discuss the aspect of the 4th industrial revolution and intelligent government, then suggest operating strategies in the field of electronic voting, electronic contract, management of resident registration and electronic document and real-estate registration.

• The Korean Journal of Archival Studies
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• no.38
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• pp.3-35
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• 2013

The physical access or control of records with material entities is relatively easy. However, in the case of electronic records, due to its heightened applicative aspect that allows anyone with the authority to have access over the data, it requires an appropriate standard and stability to ensure the authenticity and integrity of electronic records. This study performed functional evaluation by extracting the minimum critical items from the national functional requirements documents and standards to explore the access control function that play an important role for the standard records management system to maintain quality requirements of electronic records. Based on this checklist, it evaluates whether the standard records management system properly carries out the access control function and investigates the current condition of application to practical records management work. Records managers generally do not use access control function, which may be because they do not feel the necessity, since the application of records management system is not yet actively promoted. In order for the standard records management system to be developed to become a more active system, it requires system improvement as well as considerations for below factors: First, although the necessity of establishing access control conditions is already recognized, it requires a clear stipulation of the regulation. Second, measures must be taken to implement access control in the records management system through document security solution. Third, it requires self-reflection of records manager, who utilizes the records management system. Instead of placing all responsibility on the National Archives, which established the system, professionals must further develop the system through continuous evaluation and improvement. Finally, a general discussion is required to publicize the issue of functional improvement of records management system. Although there is a bulletin board already created for this purpose, its users are extremely limited and it only deals with current problems. A space in online as well as in offline is required to solve the fundamental problems and exchange opinions.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.53-65
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• 2021

C-ITS(Cooperative Intelligent Transport System) that pursues traffic safety and convenience uses various sensors to generate traffic information. Therefore, it is necessary to improve the sensor-related technology to increase the efficiency and reliability of the traffic information. Recently, the role of CCTV in collecting video information has become more important due to advances in AI(Artificial Intelligence) technology. In this study, we propose to identify and track dynamic objects(vehicles, people, etc.) in CCTV images, and to analyze and provide information about them in various environments. To this end, we conducted identification and tracking of dynamic objects using the Yolov4 and Deepsort algorithms, establishment of real-time multi-user support servers based on Kafka, defining transformation matrices between images and spatial coordinate systems, and map-based dynamic object visualization. In addition, a positional consistency evaluation was performed to confirm its usefulness. Through the proposed scheme, we confirmed that CCTVs can serve as important sensors to provide relevant information by analyzing road conditions in real time in terms of road infrastructure beyond a simple monitoring role.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.139-149
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• 2010

Internet was designed for network scalability and best-effort service which makes all hosts connected to Internet to be vulnerable against attack. Many papers have been proposed about attack detection algorithms against the attack using IP spoofing and DoS/DDoS attack. Purpose of DoS/DDoS attack is achieved in short period after the attack begins. Therefore, DoS/DDoS attack should be detected as soon as possible. Attack detection algorithms using false alarm rates consist of the false negative rate and the false positive rate. Moreover, they are important metrics to evaluate the attack detections. In this paper, we analyze the performance of the attack detection algorithms using the impact of false negative rate and false positive rate variation to the normal traffic and the attack traffic by simulations. As the result of this, we find that the number of passed attack packets is in the proportion to the false negative rate and the number of passed normal packets is in the inverse proportion to the false positive rate. We also analyze the limits of attack detection due to the relation between the false negative rate and the false positive rate. Finally, we propose a solution to minimize the limits of attack detection algorithms by defining the network state using the ratio between the number of packets classified as attack packets and the number of packets classified as normal packets. We find the performance of attack detection algorithm is improved by passing the packets classified as attacks.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.73-80
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• 2010

A wireless sensor network which is deployed in hostile environment can be easily compromised by attackers. The selective forwarding attack can jam the packet or drop a sensitive packet such as the movement of the enemy on data flow path through the compromised node. Xiao, Yu and Gao proposed the checkpoint-based multi-hop acknowledgement scheme(CHEMAS). In CHEMAS, each path node enable to be the checkpoint node according to the pre-defined probability and then can detect the area where the selective forwarding attacks is generated through the checkpoint nodes. In this scheme, the number of hops is very important because this parameter may trade off between energy conservation and detection capacity. In this paper, we used the fuzzy rule system to determine adaptive threshold value which is the number of hops for the ACK packets. In every period, the base station determines threshold value while using fuzzy logic. The energy level, the number of compromised node, and the distance to each node from base station are used to determine threshold value in fuzzy logic.