• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.397-404
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• 2006

Successful software attacks require both injecting malicious code into a program's address space and altering the program's flow control to the injected code. Code section can not be changed at program's runtime, so malicious code must be injected into data section. Detoured flow control into data section is a signal of software attack. We propose a new software attack detection method which verify the target address of CALL, JMP, RET instructions, which alter program's flow control, and detect a software attack when the address is not in code section. Proposed method can detect all change of flow control related data, not only program's return address but also function pointer, buffer of longjmp() function and old base pointer, so it can detect the more attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6B
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• pp.387-395
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• 2005

In this paper, we propose an end-to-end mobility management and TCP flow control scheme which considers different link characteristics for vertical handover environments. The end-to-end mobility management is performed by using SIP protocol. When a mobile node moves to a new network, it informs its movement of the correspondent node by sending SIP INFO message containing a new IP address which will be used in the new network. And then the corresponding node encapsulates all packets with the new IP address and sends them to the mobile node. in general, RTT of WLAN is shorter than RTT of cdma2000. when the MN moves from WLAN network to cdma2000 network, TCP retransmission timeout will be occurred in spite of non congestion situations. Thus, TCP congestion window size will be decreased and TCP throughput will be also decreased. To prevent this phenomenon, we propose a method using probe packets after handover to estimate a link delay of the new network. We also propose a method using bandwidth ratio of each network to update RTT. It is shown through NS-2 simulations that the proposed schemes can have better performance than the previous works.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5344-5356
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• 2018

Nowadays with the help of Location-Based Social Networks (LBSNs), users of Point-of-Interest (POI) recommendation service in LBSNs are able to publish their geo-tagged information and physical locations in the form of sign-ups and share their experiences with friends on POI, which can help users to explore new areas and discover new points-of-interest, and promote advertisers to push mobile ads to target users. POI recommendation service in LBSNs is attracting more and more attention from all over the world. Due to the sparsity of users' activity history data set and the aggregation characteristics of sign-in area, conventional recommendation algorithms usually suffer from low accuracy. To address this problem, this paper proposes a new recommendation algorithm based on a novel Preference-Content-Region Model (PCRM). In this new algorithm, three kinds of information, that is, user's preferences, content of the Point-of-Interest and region of the user's activity are considered, helping users obtain ideal recommendation service everywhere. We demonstrate that our algorithm is more effective than existing algorithms through extensive experiments based on an open Eventbrite data set.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.689-697
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• 2005

The IETF has created the v6ops Working Group to assist IPv6 transition and propose technical solutions to achieve it. But it's quite problem which security consideration for a stage of IPv4/IPv6 transition and co-existence. There are new security problem threat that it caused by the characteristics of heterogeneity. In this paper, we describe IPv6 transition mechanisms and analyze security problem for IPv6 transition mechanism. also we propose security consideration and new security mechanism. We analyzed DoS and DRDoS in 6to4 environment and presented a address sanity check as a solution. We also showed an attack of address exhaustion in address allocation server. To solve this problem, we proposed challenge-response mechanism in DSTM.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.446-465
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• 2015

In this modern era of technology and information, e-learning approach has become an integral part of teaching and learning using modern technologies. There are different variations or classification of e-learning approaches. One of notable approaches is Personal Learning Environment (PLE). In a PLE system, the contents are presented to the user in a personalized manner (according to the user's needs and wants). The problem arises when a new user enters the system, and due to the lack of information about the new user's needs and wants, the system fails to recommend him/her the personalized e-learning contents accurately. This phenomenon is known as cold-start problem. In order to address this issue, existing researches propose different approaches for recommendation such as preference profile, user ratings and tagging recommendations. In this research paper, the implementation of a novel interaction-based approach is presented. The interaction-based approach improves the recommendation accuracy for the new-user cold-start problem by integrating preferences profile and tagging recommendation and utilizing the interaction among users and system. This research work takes leverage of the interaction of a new user with the PLE system and generates recommendation for the new user, both implicitly and explicitly, thus solving new-user cold-start problem. The result shows the improvement of 31.57% in Precision, 18.29% in Recall and 8.8% in F1-measure.

• Journal of Information Processing Systems
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• v.13 no.2
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• pp.348-359
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• 2017

Nowadays most vehicles are equipped with a variety of electronic devices to improve user convenience as well as its performance itself. In order to efficiently interconnect these devices with each other, Controller Area Network (CAN) is commonly used. However, the CAN requires reconfiguration of the entire network when a new device, which is capable of supporting both of transmission and reception of data, is added to the existing network. In addition, since CAN is based on the collision avoidance using address priority, it is difficult that a new node is assigned high priority and eventually it results in transmission delay of the entire network. Therefore, in this paper we propose a new system component, called CAN coordinator, and design a new CAN framework capable of supporting plug and play functionality. Through experiments, we also prove that the proposed framework can improve real-time ability based on plug and play functionality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.875-887
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• 2010

The workgroup of IEEE 802 proposed the IEEE 802.16 standard, also known as WiMAX, to provide broadband wireless access (BWA). The standard specifies two operational modes, one is popular PMP mode, and the other is optional mesh mode. In the mesh mode, the network entry process-NetEntry is the pivotal procedure for mesh network topology formulation and thus, influences the accessibility of whole mesh network. Unfortunately, the NetEntry process suffers from the hidden neighbor problem, in which new neighborship emerges after a new node comes in and results in possible collisions. In this paper, we propose a new SN-protected NetEntry process to address the problem. Simulation results show that the new proposed NetEntry process is more stable compared with the standard-based NetEntry process.

• Journal of KIISE:Software and Applications
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• v.27 no.4
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• pp.327-341
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• 2000

This paper presents a method for procedure-based on-line program replacement for user applications and illustrates the method in the SUN Solaris environment. In addition to developing procedures for directly changing the address space of a running process, the paper provides solutions on how to allocate space for the new version procedure and how to make the new version procedure work correctly in the old version process address space, when the size of new version procedure is different from that of old version, and thus facilitates procedure-based on-line software replacement. The method performs on-line program replacement using services provided by existing operating systems. Also, the method supports a small, procedure-based replacement and directly modifies necessary parts of a process address space, which results in small performance loss.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.540-543
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• 2004

Address Resolution Protocol (ARP) cache poisoning is a MAC layer attack that can only be carried out when an attacker is connected to the same local network as the target machines. ARP is not a new problem, but wireless network introduces a new attack point and more vulnerable to the attack. The attack on wireless network cannot be detected by current detection tool installed on wired network. In order to detect the ARP poisoning attack, there must be a ARP poisoning detection tool for wireless LAN environment. This paper proposes linux-based ARP poisoning detection system equipped with wireless LAN card and Host AP device driver

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2434-2454
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• 2021

This paper developed the software testing factory-cloud testing platform (STF-CTP) to address the software compatible issues in various smart devices. Software developers who only require uploading the application under test (AUT) and test script can test plenty of smart devices in STF-CTP. The challenge for the cloud test platform is how to optimize the resource and increase the performance in the limited resource. This paper proposed a new scheduling mechanism and a new process of the system operation which is based on the OpenStack platform. We decrease about 40% memory usage of OpenStack server, increase 3% to 10% Android device usage of STF-CTP, enhance about 80% test job throughput and reduces about 40% test job average waiting time.