• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.325-338
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• 2004

As the recent rapid development of internet technology and the wide spread of multimedia communication, massive increase of network traffic causes some problems such as the lack of network paths and the bad quality of service. To resolve these problems, this paper presents a traffic control agent that can perform the dynamic resource allocation by controlling traffic flows on a DiffServ network. In addition, this paper presents a router that can support DiffServ on Linux to support selective QoS in IP network environment. To implement a method for selective traffic transmission based on priority on a DiffServ router, this paper changes the queuing discipline in Linux, and presents the traffic control agent so that it can efficiently control routers, efficiently allocates network resources according to service requests, and relocate resources in response to state changes of the network. Particularly for the efficient processing of Assured Forwarding(AF) Per Hop Behavior(PHB), this paper proposes an ACWF$^2$Q$^{+}$ packet scheduler on a DiffServ router to enhance the throughput of packet transmission and the fairness of traffic services.s.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.97-100
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• 2003

This paper propose a simple and efficient scheme to deliver frames between TDM interfaces and IP interfaces in NGTSs. Next Generation Transport Systems (NGTSs) are new conceptual transmission equipments fur next generation network. They consist of TDM interfaces and IP interfaces. NGTSs are suitable fur high-speed transmission links such as SONET/SDH and Gigabit Ethernet. The proposed VLAN scheme for NGTSs is implemented successfully.

• Journal of the Korea Society of Computer and Information
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• v.27 no.9
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• pp.113-120
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• 2022

In this paper, we analyze the feasibility of the IP spoofing attack exploiting null security algorithms in 5G networks based on 3GPP standard specifications. According to 3GPP standard specifications, the initial Registration Request message is not protected by encryption and integrity. The IP spoofing attack exploits the vulnerability that allows a malicious gNB (next generation Node B) to modify the contents of the initial Registration Request message of a victim UE (User Equipment) before forwarding it to AMF (Access and Mobility Management Function). If the attack succeeds, the victim UE is disconnected from the 5G network and a malicious UE gets Internet services, while the 5G operator will charge the victim UE. In this paper, we analyze the feasibility of the IP spoofing attack by analyzing whether each signaling message composing the attack conforms to the 3GPP Rel-17 standard specifications. As a result of the analysis, it is determined that the IP spoofing attack is not feasible in the 5G system implemented according to the 3GPP Rel-17 standard specifications.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.438-443
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• 2020

To transfer files between nodes on network based on Ethernet, file transfer protocol (FTP) on TCP/IP and trivial file transfer protocol (TFTP) on UDP/IP are mostly used. Due to the lack of resources (processor, memory and so on) in the embedded system where we generally use for simple works with small firmware like ones; many of the systems implement only UDP/IP for their network stacks. Thus, TFTP is greatly to be preferred. For examples, environmental sensor devices for sensor networks, Boot Loader for general embedded device and preboot execution environment (PXE) boot for PC provide the TFTP. The logic of TFTP is simple for file transmission but, there is Stop-And-Wait problem during the process which occurs long blocking time. In this paper, we propose an algorithm which called QuTFTP(Quick UDP Trivial File Transfer Protocol) to reduce the length of the blocking time and to be compatible with the legacy TFTP.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.205-218
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• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.2
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• pp.116-122
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• 2007

System management application system is one of the most interesting fields in Ubiquitous Sensor Networks. It conforms to the property of Ubiquitous Sensor Networks very well, and it is the closest application for commercial use. We have two kinds of system management technology, such as the one which is accessed by web browser at anytime, anywhere and another one which is for local accessed system. In this paper, our purpose is implementation of system management application system which provides Mesh Sensor Networks topology with IP based agent platform and system management server. Furthermore we introduce the functions used for our recent implementation and propose several future issues about system management application system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.787-793
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• 2008

3GPP evolved packet system (EPS) is an all-IP based system that supports various access networks such LTE, HSPA/HSPA+, and non-3GPP networks. Recently, the support of IP flows with packet level QoS profiles was added to the requirements of the EPS. This paper proposes an adaptive modulation and coding (AMC) scheme that supports the QoS of such IP flows in the 3G LTE access network of the EPS. Defining the retransmission as a critical factor for QoS, the proposed scheme applies different maximum packet error probability $P_{max}$ to each packet when selecting the AMC transmission mode. In determining $P_{max}$, the QoS constraints and NACK-to-ACK error as well as channel condition are considered, balancing two objectives: the satisfaction of the QoS and the maximization of spectral efficiency. The simulation results show that it is able to reduce both delay violation and status report by 10%, while improving the throughput 10% in comparison with an existing scheme.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.401-415
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• 2019

Recently, there has been a lot of studies and efforts to strengthen the stability of critical infrastructures against increasing cyber attacks to critical infrastructures. In this thesis, I defined what cyber threats are, after showing you various definitions about what cyber threats are and what the types are. After studying about significant cyber threats from China, I showed you the realities of cyber threats with the analysis about starting points, types of cyber threats, ratios of attacks and so on. At last, I defined guidelines about unnecessary oversea IP range blocking. Also, I proposed unnecessary oversea IP range blocking methodologies with per information system and per network system. Furthermore, I proposed blocking characteristics per security equipment and security operation improvement and blocking effects and service process to normal oversea users.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.360-367
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• 2005

Corporation's computerization developed by diffusion of internet, and dysfunction of Information is increasing greatly with virus, computing network infringement. Therefore, the today, corporation security is more and more emphasized. Security solution by that importance of security rises so is developing together Security solution is developing to ESM system in existing single system and important thing is function of each security solution and optimizing design of policy. Existent security policy taking a serious view security from external invasion but security of interior the importance rise the today. Accordingly, must construct ESM system of new structure for this. This paper proposes and embodied integration security administration system that solidify interior security utilizing IDS. Experiment external IP and ID access and analyzed the result.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.531-535
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• 2002

This paper presents a real-time collaborative system for distributed design. The aim of the system is to provide designers with a virtual workspace where they can collaborate and exchange their design knowledge in distributed environment. The system consists of two subsequent modules. One is for the visualization of design data including CAD data, documents, images, and the other is real-time collaboration module. They make it possible for distributed designers to review the design data collaboratively and to share their design knowledge. The system was implemented by using the Internet protocols such as TCP/IP and IP multicast on the peer-to-peer based network. An example is presented and discussed to validate the proposed system.