• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.71-75
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• 2008

Many sensor operating systems have memory limitation constraint; therefore, stack memory areas of threads resides in a single memory space. Because most target platforms do not have hardware MMY (Memory Management Unit), it is difficult to protect each stack area. The method to solve this problem is to exchange original stack handling instructions in binary code for wrapper routines to protect stack area. In this exchanging phase, instruction corruption problem occurs due to difference of each instruction length between stack handling instructions and branch instructions. In this paper, we propose the algorithm to call a target routine without instruction corruption problem. This algorithm can reach a target routine by repeating branch instructions to have a short range. Our solution makes it easy to apply security patch and maintain upgrade of software of sensor node.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.405-410
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• 2013

Due to the enforcement of a law about disability nondiscrimination and rights protection in 2008, the web accessibility has become an obligation. According to a survey targeting public sectors such as central administrative organization, local autonomous entity and etc., the level of compliance with web accessibility appeared to be improved every year. However, such legal mechanism focuses on the improvement of convenience for disabled people only and does not meet the concept of universal design that aims to satisfy every user. Therefore, this study verifies the status of web accessibility on 17 homepages of metropolitan and provincial offices of education. The status survey was carried out with 3 steps: 1) Verification through automated verification tool by National Information Society Agency, 2) Verification through Web Content Accessibility Guidelines(UD-WCAG) that adopts the concept of universal design, 3) Verification by using screen reader. Compared to the verification through automated verification tool, the overall compliance rate verified through UD-WCAG was reported lower.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.159-172
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• 2018

This study searched and analyzed online tracking technologies. It tried to understand what to consider when establishing policies related to online tracking. Online tracking technologies were classified into 'general cookies', 'super cookies', 'fingerprinting', 'device ID tracking' and 'cross-device tracking'. Political considerations should include the layers of online tracking, the subjects of tracking technology, purpose of use, duration and storage format of information, and development of technology. The implications of this study are as follows: first, policy makers and industry should be aware that the degree of risk perceived by users may vary according to the characteristics of online tracking technology. Secondly, it is necessary to understand factors that affect the classification of online tracking technology. Finally, in the industry, preemptive measures such as building an integrated privacy system are needed to relieve anxiety of users and to build trust.

• Journal of KIISE
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• v.44 no.10
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• pp.1005-1018
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• 2017

Recently, virtualization has become an essential component of cloud computing due to its various strengths, including maximizing server resource utilization, easy-to-maintain software, and enhanced data protection. However, since virtualization allows sharing physical resources among the VMs, the system performance can be deteriorated due to device contentions. In this paper, we first investigate the I/O overhead based on the number of VMs on the same server platform and analyze the block I/O process of the KVM hypervisor. We also propose an in-memory block cache mechanism, called QBic, to overcome I/O virtualization latency. QBic is capable of monitoring the block I/O process of the hypervisor and stores the data with a high access frequency in the cache. As a result, QBic provides a fast response for VMs and reduces the I/O contention to physical devices. Finally, we present a performance measurement of QBic to verify its effectiveness.

• KIISE Transactions on Computing Practices
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• v.23 no.8
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• pp.504-509
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• 2017

Preserving the integrity of the booting process is important. Recent rootkit attacks and subverting OS attacks prove that any post-OS security mechanism can be easily circumvented if the booting process is not properly controlled. Using an actual case as an example, the hacker of the Se-jong government office simply bypassed the user's password authentication by compromising the normal booting process. This paper analyzes existing pre-OS protection using secure boot and measured boot, and proposes another bootloader that overcomes the limitations. The proposed bootloader not only guarantees the integrity of all the pre-OS binaries, bootloaders, and kernel, it also makes explicit records of integrity in the booting process to the external TPM device, so that we can track modifications of BIOS configurations or unintended booting process modifications.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.323-330
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• 2007

Recently, due to the effective land utilization and environmental protection, the construction of 2-arch tunnel has been gradually increased. In spite of this tendency, the mechanical information for the 2-arch tunnel, especially such as its behavior characteristics and mechanism are not enough. Therefore in this study, the theoretical and numerical studies on the behavior characteristics of 2-arch tunnel are carried out and longitudinal optimum separated distance of tunnel face is proposed by considering the analysis results from the behavior of advanced excavation of tunnel and stress of central pillar. As a result, longitudinal optimum separated distance of tunnel face is in 0.5D for the better safety of 2-arch tunnel by rapidly decreasing the stress concentration of central pillar.

• Convergence Security Journal
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• v.15 no.4
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• pp.35-41
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• 2015

Internet of Things has a wide range of vulnerabilities are exposed to information security threats. However, this does not deal with the basic solution, the vaccine does not secure encryption for the data transmission. The encryption and authentication message transmitted from one node to the construction of the secure wireless sensor networks is required. In order to satisfy the constraint, and security requirements of the sensor network, lightweight encryption and authentication technologies, the light key management technology for the sensor environment it is required. Mandatory sensor network security technology, privacy protection technology subchannel attack prevention, and technology. In order to establish a secure wireless sensor networks encrypt messages sent between the nodes and it is important to authenticate. Lightweight it shall apply the intrusion detection mechanism functions to securely detect the presence of the node on the network. From the sensor node is not involved will determine the authenticity of the terminal authentication technologies, there is a need for a system. Network security technology in an Internet environment objects is a technique for enhancing the security of communication channel between the devices and the sensor to be the center.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.12
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• pp.714-723
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• 2003

In order to guarantee system survivability against attacks based on new methodology, we need a solution to recognize important resources for essential services and to adapt the urgent situation properly. In this paper, we present a dynamic resource reallocation scheme which is one of the core technologies for the implementation of intrusion tolerant systems. By means of resource reallocation within a node, this scheme enables the essential services to survive even after the occurrence of a system attack. If the settlement does not work within the node, resource reallocation among nodes takes places, thus the essential services are transferred to another prepared server node. Experimental result obtained on a testbed reveals the validity of the proposed scheme for resource reallocation. This scheme may work together with IDS(Intrusion Detection System) to produce effective responsive mechanism against attacks.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.05a
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• pp.8-13
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• 2003

Historically, IP-based internets have been able to provide a simple best-effort delivery service to all applications they carry. Best effort treats all packets equally, with no service level, packet loss, and delay. But the needs of users have changed. The want to use the new real-time, multimedia, and multicasting applications. Thus, there is a strong need to be able to support a variety of traffic with a variety of quality-of-service requirements. The DiffServ architecture, proposed by the Internet Engineering Task Force(IETF), has become the most viable solution for provising QoS over IP networks. The DiffServ architecture does not specify any handling method between AF out-profile packets and BE packets. This paper propose a mechanism for supporting inter class fairness in the DiffServ architecture. Ⅰ proposed a modified Weighted Round Robin method to protect the BE traffic from AF out-profile packets in the core routers. The proposed technique is evaluated through simulation. Simulation results indicate that the proposed method provides better protection not only for BE packets from AF out-profile packets, but also for the AF in-profile packets in congested networks.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.449-460
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• 2012

Plants have versatile detoxification systems to encounter the phytotoxicity of the wide range of natural and synthetic compounds present in the environment. Glutathione S-transferase (GST) is an enzyme that detoxifies natural and exogenous toxic compounds by conjugation with glutathione (GSH). Recently, several roles of GST giving stress tolerance in plants have demonstrated, but little is known about the role of ginseng GSTs. Therefore, this work aimed to provide further information on the GST gene present in Panax ginseng genome as well as its expression and function. A GST cDNA (PgGST) was isolated from P. ginseng cDNA library, and it showed the amino acid sequence similarity with theta type of GSTs. PgGST in ginseng plant was induced by exposure to metals, plant hormone, heavy metals, and high light irradiance. To improve the resistance against environmental stresses, full-length cDNA of PgGST was introduced into Nicotiana tabacum. Overexpression of PgGST led to twofold increase in GST-specific activity compared to the non-transgenic plants, and the GST overexpressed plant showed resistance against herbicide phosphinothricin. The results suggested that the PgGST isolated from ginseng might have a role in the protection mechanism against toxic materials such as heavy metals and herbicides.