• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.565-568
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• 2011

Google Android framework consists of an operating system and software platform for mobile devices. Using a general-purpose Linux operating system in mobile device has some advantages but also security risks. Security-Enhanced Linux (SELinux) is a kernel-based protection approach which can help to reduce potential damage from successful attacks. However, there are some challenges to integrate SELinux in Android. In this research, we do a study on how to do the integration and find out four challenges. The first one is that the Android file system (yaff2) does not support security namespace for extended attribute (xattr) which is required by SELinux. The second one is that it's difficult to apply SELinux policy to Dalvik process on which an Android application runs on. The third one is that Android lacks methods, tools and libraries to interact with SELinux. The last one is how to update the SELinux policy automatically when installing or removing an application. In this paper, we propose solutions for the above limitations that make the SELinux more adaptive and suitable for Android framework.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.6
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• pp.1049-1055
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• 2013

Smartphones are rapidly growing because of easy installation of the apps (application software) that users actually want. There are increasingly many apps that require cryptographic suites to be installed, for instance, for protecting account and financial data. Android platform provides protection mechanisms for memory and storage based on Linux kernel, but they are vulnerable to rooting attacks. In this paper, we analyze security mechanisms of Android platform and point out security problems. We show the security vulnerabilities of several commercial apps and suggest appropriate countermeasures.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.162-162
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• 1998

Various natural compounds act as antioxidants in protection against lipid peroxidation. Lipid peroxidation yields a variety of decomposition products which have been implicated in not only decreasing the nutritional value of food, but also in developing an off-flavor and toxic substances. As a source of safer and more effective natural antioxidants of natural origin have been widely investigated. Some Indonesian plants have evaluated for their antioxidative activity, and suggested the possible existence of various antioxygenic compounds in them. We attempted to study such antioxygenic compounds with simple method evaluation. As we are interested in the natural product compounds, we examined of several sample such as edible sea-weeds, and some edible fruits. Sea-weed, Eisenia bicyclis, one of the edible brown algae, exhibited the activity. As a traditional food additive consumed by Indonesian, Garcinia parvifolia is used as taste supplement in region West Sumatra, have been studied. Our current studies on the semi-polar fractions shows the activity by the thiocyanate method test. Another sample, Garcinia mangostana, a famous fruit with sweet taste, the part kernel have also evaluated. The acidic fraction of the extract showed antioxidative activity. Some other active components were found in the neutral and BuOH fractions.

• Journal of Plant Biology
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• v.29 no.4
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• pp.295-315
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• 1986

Structure and differentiation mechanism of the seed coat of Panax ginseng are studied with light and electron microscopes to clarify the developmental processes of seed coat and the structural changes during the differentiation of the seed. The seed coat of ginseng is differentiated from the inner cell layers of ovary wall, which can be compared with the seed coat differentiated from integument(s) in other plants. The single integument is differentiated into endothelium, which is degenerated to one layer of 4${\mu}{\textrm}{m}$ in thickness, composed of remants of cell wall components in fully ripened seed. The ripened seed coat is composed of three layers; fringe layer, inner layer and palisade layer, and all of the them are crossed at right angles with one another. This may be the cause of protection of the kernel from other mechanical injuries. The thickness of fully ripened seed coat is about 300~600 ${\mu}{\textrm}{m}$, and arrangements of sclereids are irregular. However, the raphe region of seed coat is thin about 200 ${\mu}{\textrm}{m}$ in thickness and sclereids in that region are arranged regularly. This is the important cause for the cleavage of the seed coat during post-maturation process. The vascular bundles on the raphe are still remaining after sarcocarps are removed, and one of the branches of vascular bundles entered into the seed coat through the hilum and extended to chalazal region. During post-maturation process, the supply of water being necessary for growth of embryo may be accompolished by the vascular bundles entered into the seed coat through the opened hilum.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.971-974
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• 2002

일반적으로 악의적인 사용자는 시스템에 공격을 가해 관리자 권한을 취득한 후 그 시스템에 쉽게 침입하기 위해 백도어를 설치해 놓는다. 이전의 백도어는 대부분 사용자 영역에서 수행중인 응용 프로그램의 형태로 설치가 되었다. 그러나 최근에는 로더블 모듈과 같은 운영체제의 확장 방법을 이용하여 커널 영역에서 수행되는 백도어가 나타나게 되었다. 이러한 커널 백도어를 구현하는 방식은 크게 시스템 콜 테이블을 수정하는 방법과 시스템 콜 처리 루틴을 수정하는 방법의 두 가지로 나눌 수 있다. 본 논문에서는 기존에 구현된 커널 백도어의 특성 분석을 하였으며, 이를 기반으로 커널 백도어를 효율적으로 차단 및 탐지할 수 있는 방안을 제안하고 있다. 본 논문에서 언급하는 방안은 커널 메모리 영역에 대한 분석을 통하여 백도어가 시스템 콜 테이블을 수정하거나 시스템 콜 처리 루틴을 변경할 수 없도록 하는 보호 메커니즘을 적용하고 있다. 이를 통하여 커널 내부로 적재되어 백도어를 생성하는 악의적인 모듈의 가능성을 원천적으로 방지할 수 있다.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

• Journal of Ocean Engineering and Technology
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• v.27 no.4
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• pp.90-97
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• 2013

Oil booms are one of the most widely used types of equipment for the protection of coastal areas against oil spills. In some situations, however, there are several types of oil leaks from the oil boom. Important factors regarding these phenomena include the surrounding ocean environment, such as waves, the density and viscosity of oil, the length of the oil boom skirt, etc. To estimate the performance of the oil boom, it is necessary to predict the behavior of the spilled oil and oil boom. In the present study, the prediction of oil boom performance in waves was carried out using the Pusan-National-University-modified Moving Particle Semi-implicit (PNU-MPS) method, which is an improved version of the original MPS proposed by Koshizuka and Oka (1996). The governing equations, which consist of continuity and Navier-Stokes equations, are solved by Lagrangian moving particles, and all terms expressed by differential operators in the governing equations are replaced by the particle interaction models based on a kernel function. The simulation results were validated through a comparison with the results of Violeau et al. (2007)..

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1571-1574
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• 2014

In this paper, we propose a unidirectional transmission of critical information obtained by keyboard hacking or kernel and keyboard driver hacking even though the computer is not connected to the external network. We show the hacking can be attempted in the proposed method to show the way preventing such attempts in advance. Firewalls and other various methods are used to prevent the hacking from the external network but the hacking is also attempted in various ways to detour the firewall. One of the most effective way preventing from the hacking attack is physically disconnect the internal intranet systems from the external internet and most of the government systems, military systems and big corporate systems are using this way as on one of the protection method. In this paper, we show the feasibility of transmission of security codes, etc via the short message to the external network on the assumption that a hacking program such as Trojan Horse is installed on the computer systems separated from the external network. Previous studies showed that the letters on the monitor can be hijacked by electromagnetic analysis on the computer to obtain the information even though the system is not connected ti the network. Other studies showed that the security code hint can obtained by analyzing the power consumption distribution of CPU. In this paper, the power consumption distribution of externally accessible power line is analyzed to obtain the information and the information can be transmitted to the external network. Software controlling the CPU and GPU usage is designed to control the power supply of computer. The sensors such as the Rogowski coils can be used on the external power line to collect the data of power consumption change rates. To transmit the user password by short message, due to the capacitive components and the obstacle from other power supply, A very slow protocol are used.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.4
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• pp.35-42
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• 2010

This paper reviews the current studies about the current secure OS, security module and SELinux, and suggests Linux access control module that uses the user discriminating authentication, security authority inheritance of subjects and objects, reference monitor and MAC class process and real-time audit trailing using DB. First, during the user authentication process, it distinguishes the access permission IP and separates the superuser(root)'s authority from that of the security manager by making the users input the security level and the protection category. Second, when the subjects have access to the objects through security authority inheritance of subjects and objects, the suggested system carries out the access control by comparing the security information of the subjects with that of the objects. Third, this system implements a Reference Monitor audit on every current events happening in the kernel. As it decides the access permission after checking the current MAC security attributes, it can block any malicious intrusion in advance. Fourth, through the real-time audit trailing system, it detects all activities in the operating system, records them in the database and offers the security manager with the related security audit data in real-time.