• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.717-723
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• 2020

Determination of local tie vectors between the space geodetic techniques such as VLBI (Very Long Baseline Interferometer), SLR (Satellite Laser Ranging), DORIS (Doppler Orbit determination and Radiopositioning Integrated on Satellite), GNSS (Global Navigation Satellite System) is essential for combination of ITRF (International Terrestrial Reference Frame). Therefore, it is required to compute IVP (Invariant Point) position of each space geodetic technique with high accuracy. In this study, we have computed Sejong VLBI IVP position by using updated mathematical model for adjustment computation so that the improvement on efficiency and reliability in computation are obtained. The measurements used for this study are the coordinates of reflective targets on the VLBI antenna and their accuracies are set to 1.5 mm for each component. The results show that the position of VLBI IVP together with its standard deviation is successfully estimated when they are compared with those of the results from previous study. However, it is notable that additional terrestrial surveying should be performed so that realistic measurement errors are incorporated in the adjustment computation process.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1679-1686
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• 2019

The main purpose of this research is to propose an approach for solving the packet loss problem by quickly adapting to topology change when nodes move in RPL-based IoT environment. In order to enhance mobility, every node is aware of the mobility of its neighbor nodes and quantifies the mobility level based on the number of control messages and all received packets. According to the mobility level, the DIO timer is changed. The proposed approach allows nodes to change their DIO timers according to their mobility levels to adapt topology changes and update paths to the sink. The performance of the proposed approach is evaluated using a Contiki-based Cooja simulator in various moving speeds. The simulation results show that the proposed approach copes with mobility scenarios better than the standard RPL by ascertaining that the packet delivery ratio is improved by 31.03%.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.5
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• pp.7-18
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• 2018

Recently, serverless computing is spotlighted. Because it supports the development of application based on micro-service. Micro-service means a small-scale service that can operate independently. Applications with micro-service units have the advantage of enabling individual updates, easy and fast deployment. In addition, it has the advantage of supporting various languages and platforms for each service. Therefore many enterprise are trying to change from monolithic architecture to micro-service based architecture. However, there is a lack of research on methods and baseline for micro-service construction. In this paper, a method is proposed to construct the micro-service unit by analyzing UML design in monolithic application. It also shows the proposed approach can reconstruct monolithic application into micro-service based unit by implementing the constructed micro-services in a real serverless platform environment. In addition, the results of the comparative evaluation with the related studies are presented.

• The Journal of Korean Institute of Next Generation Computing
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• v.14 no.6
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• pp.15-29
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• 2018

This paper proposes an enhanced object tracking algorithm to compensate the lack of temporal information in existing particle swarm optimization based object trackers using the trajectory of the target object. The proposed scheme also enables the tracking and documentation of the location of an online updated set of distractions. Based on the trajectories information and the distraction set, a rule based approach with adaptive parameters is utilized for occlusion detection and determination of the target position. Compare to existing algorithms, the proposed approach provides more comprehensive use of available information and does not require manual adjustment of threshold values. Moreover, an effective weight adjustment function is proposed to alleviate the diversity loss and pre-mature convergence problem in particle swarm optimization. The proposed weight function ensures particles to search thoroughly in the frame before convergence to an optimum solution. In the existence of multiple objects with similar feature composition, this algorithm is tested to significantly reduce convergence to nearby distractions compared to the other existing swarm intelligence based object trackers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.43-53
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• 2007

Internet becomes more and more popular, and most companies and institutes use web services for e-business and many other purposes. With the explosion of Internet, the occurrence of cyber terrorism has grown very rapidly. Simulation is one of the most widely used method to study internet worms. But, it is quite challenging to simulate very large-scale worm attacks because of various reasons. In this paper, we propose a hybrid modeling method for RCS(Random Constant Spreading) worm simulation. The proposed hybrid model simulates worm attacks by synchronizing modeling network and packet network. So, this model will be both detailed enough to generate realistic packet traffic, and efficient enough to model a worm spreading through the Internet. Moreover, our model have the capability of dynamic updates of the modeling parameters. Finally, we simulate the hybrid model with the CodeRed worm to show validity of our proposed model for RCS worm simulation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.145-156
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• 2010

Now a days, the development of TV and internet like communicational technique makes IPTV service which combines internet with multimedia contents increase. But when a user gets service in specific place, the certification process and user's ID check in IPTV service is complicate so that there occurs communicational difficulty like increasing illegal users and service delay etc. This paper proposes communication security mechanism to prevent Clone attack which happens in wireless section by efficiently extracting illegal user. The proposed mechanism performs key distribution procedure, inter certification procedure, and key initiation procedure by putting security agent in RFID-USB for RFID tags users use to perform plug-and-plug function. Also, the proposed mechanism updates the hased token value by its ID and the random number which RFID-USB creates whenever a user accesses in the area of RFID-USB so that it protects reply attack and man-in-the-middle attack which happen often in the area of wireless section.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.101-110
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• 2011

Recently, an attack to an application incapacitates the intrusion detection rule, the defense policy for a network and database and induces intrusion incidents. Thus, it is necessary to study integration security to ensure the security of an internal network and database from that attack. This article is about building an integration security system to prevent an attack to an application set with intrusion detection rules. It responds to network-based attack through detection, disperses attack with the internal integration security system through virtual clustering and load balancing, and sets up defense policy for attacking destination packets, analyzes and records attack packets, and updates rules through monitoring and analysis. Moreover, this study establishes defense policy according to attacking types to settle access traffic through virtual machine partition policy and suggests an integration security system applied to prevent attack and tests its defense. The result of this study is expected to provide practical data for integration security defense for hacking attack from outside.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.3
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• pp.433-441
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• 2021

Android applications are released across various categories, including productivity apps and games, and users are exposed to various applications and even malware depending on their usage patterns. On the other hand, most analysis engines train using existing datasets and do not reflect user patterns even if periodic updates are made. Thus, the detection rate for known malware is high, while types of malware such as adware are difficult to detect. In addition, existing engines incur increased service provider costs due to the cost of server farm, and the user layer suffers from problems where availability and real-timeness are not guaranteed. To address these problems, we propose an analysis system that performs on-device malware detection through transfer learning, which requires only one-time communication with the server. In addition, The system has a complete process on the device, including decompiler, which can distribute the load of the server system. As an evaluation result, it shows 90.3% accuracy without transfer learning, while the model transferred with adware catergories shows 95.1% of accuracy, which is 4.8% higher compare to original model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.703-713
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• 2022

Accurate and rapid establishment of mobile communication is important in mobile communication system. Currently, the base station parameters to establish a network are determined by cell planning tool. However, it is necessary to perform new cell planning for each new installation of the base station, and there may be a problem that parameters are not suitable for the actual environment are set, such as obstacle information that is not applied in the cell planning tool. In this paper, we proposed methods for path loss prediction using DNN and topographical division using CNN in SON server. After topography classification, a SON server configures the base station parameters according to topography, and update parameters for each topography. The proposed methods can configure the base station parameters automatically that are considered topography information and environmental changes.

• Journal of The Korean Association of Information Education
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• v.26 no.1
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• pp.23-34
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• 2022

Teachers should be able to reorganize the curriculum according to the student level, reorganize textbooks freely, and distribute them to students. However, current paper-textbooks are difficult to modify or edit some contents and distribute them to students, also current digital textbooks are grouped into units, so the order or educational resources cannot be reconstructed. In addition, The digital textbooks are difficult to update external links or the latest resources, and to contain various multimedia materials or high-definition realistic content due to capacity limitations. Therefore, this study presented functions: teaching and learning and evaluation functions, resources search and sharing functions, learning records and analysis functions, screen showing and printing functions, so that teachers can provide customized learning by level to students using digital textbooks. Through the expert Delphi survey, detailed functions for each area were divided into teachers and students. We proposed expanding and developing digital textbooks to various subjects, and distributing various teaching and learning models using digital textbooks.