• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.675-682
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• 2003

Attackers collect vulnerabilities of a target computer system to intrude into it. And using several attack methods, they acquire root privilege. They steal and alter information in the computer system, or destroy the computer sysem. So far many intrusion detection systems and firewallshave been developed, but recently attackers go round these systems and intrude into a computer system . In this paper, we propose security kernel module to prevent attackers having acquired root privilege from doing illegal behaviors. It enhances administrator authentication with additional password, so prevents attackers from doing illegal behaviors such as modification of important files and installation of rootkits. It sends warning mail about sttacker's illegal behaviors to administrators by real time. So using information in the mail, they can estabilish new security policies.

• Journal of Korea Water Resources Association
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• v.32 no.2
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• pp.143-152
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• 1999

South-eastern part of Kyungbuk Province is suffering from lack of suitable water development sources due to geographic condition and insufficient water sources condition. In order to find an appropriate solution, extensive studies are carried out such as investigation of new dam sites, regional water supply system, modification of existing water supply system, rehabilitation of old water resources structures and development of off-stream reservoirs. The network optimization model is applied for evaluation of the newly suggested water development alternatives. The results show that if water supply system is constructed until 2011, the reliability of water supply to Pohang and Kyungju region will be more than 95% and the network optimization model can be used to analyse the management of water resources system considering water rights or priority orders.

• 대한공업교육학회지
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• v.32 no.2
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• pp.47-68
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• 2007

The purpose of this research was on the operation activation for specialized high schools in Chungcheongbuk-do, and conducted a survey of chief teachers of Practical Art Subject and heads of each subjects in 32 specialized high schools in district about the system reform of vocational high school, promotion of characterization for each subject, modification of curriculum, reinforcement of direction guide, of which results were analyzed. Also, another survey of small and middle businesses was conducted to investigate the demand for human resources for industrial businesses in Chungcheongbuk-do and specialized abilities required by companies. Through the study, the reform of operation activation for specialized high schools in Chungcheongbuk-do were suggested as follows. First, Specialized high schools should more focus on educating application of a computer and the basic abilities in foreign language at the request of industry. Second, If more than 80% of vocational high school graduates go to junior colleges or universities, specialized high schools should reform their operation like general high schools. Third, Specialized high schools should expand the operation of customized curriculum for neighboring industry to raise employment rate. Fourth, Specialized high schools in Chungcheongbuk-do should reform their courses which can provide students with fundamental knowledge to work in industry related to BT and IT, as Osong medical complex and Ochang IT industrial complex are expanding gradually. Fifth, Employees in companies should be applied as guest teachers, and the principal should have a right to autonomy to operate their own curriculum. Sixth, 5 years rotation system for public schools should be revised to more than 10 years rotation system for special subjects in specialized high schools. Therefore, teachers will have ownership of the school by the revised system.

• Membrane Journal
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• v.18 no.3
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• pp.206-213
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• 2008

Poly(vinylidene fluoride) (PVDF) membrane surfaces were modified using surface modifying macromolecules (SMMs). The Zonyl BA-L as SMM was used and the various PVDF membranes containing 0 to 2 wt% SMM were prepared. The resulting membranes were characterized through SEM, contact angle measurements and pervaporation separation of water-ethanol system. SMM layers were created in the surface regions of PVDF membranes by SEM images and the contact angles were increased more than untreated PVDF membranes. The pervaporation was carried out at 50, 60 and $70^{\circ}C$, and the PVDF membranes containing 1 and 2 wt% SMM were used for 10, 20, 50 wt% water in the binary water/ethanol mixtures and pure water. PVDF/2 wt% Zrlnyl BA-L membrane showed the permeability 5.3 $g/m^2hr$ and separation factor 287 at $50^{\circ}C$ for water : ethanol = 10 : 50 solution.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.141-151
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• 2013

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.563-572
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• 1997

E-mail has been eidely used for unformation delivery as an Inernet serive. As multimedia etchnologies are developed rapidly, most of the recent Unternet infornation servies support multimedia data. E-mail system also needs to suport multimedia nesage. But Internet mail servise using simple maiol transfer protocol(SMTP) speci-fied in RFC 821/822 handles only ASCII text messages repressented with 7-bit code. Each line the message has the length limitation as well. Those are why it cannot satisfy the diverse user'w demands. Multipuepose Unternet mail extensions(MIMZE), which is a modification and supplement of RFC 822,was proposed for supporting transportation of multimedia data.It can solve the limitations of sizes and types in contents of a message. In this study the E-mail system has been designed and implemented according to the MIME standard in order to solve the limitations of transpotation of messages regardless of the message content type. Hypertext markup language(HTML)syntax is applied to the mail system, and so it is possible to display a message consisting of differnt media as an intergrated from for the purpose of better understanding a message. No application program is needed for displaying a message including image data,and convenience for user is considered in the system. The futuer work is to improve the E-mail system so that it may support motion pictures and sound information,Thereby tge perfor multimeda E-mail system providing inergrated user's wiew will be developed.

• Cartoon and Animation Studies
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• s.36
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• pp.493-510
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• 2014

From game consoles to TV and Hollywood films, 3D rendering technology is involved in various fields. Up until the late 90s, the computer image rendering method was rasterization that mainly used Phong Shading, and up until recently it was the go-to method for movies and film animation. In the 21st century, the quality provided by Ray Tracing and the development of Global Illumination was much more realistic and thus became popularized. However, despite its growing use in architectural rendering to the markets, Global Illumination in film animation and movies was limited due to its long render time. So, in this thesis, if one were to take the concept from each rendering method and consider it from a mathematical perspective, one could adapt the Ambient Occlusion's equation to the illumination loop equation used in rasterization. This algorithm modification has the capability to reflect the lighting of a diverse array of colors, like in Global Illumination, with a fast render time, as in rasterization, and the example RenderMan Shader is based upon this new algorithm. In conclusion, with Global Illumination's naturalistic lighting and rasterization's rendering speed, the combination of the best points of each is a new method with a short rendering time while producing good quality. I hope animations and films can benefit from this algorithm by the reduction of budget with an overall better quality output in VFX production.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.5
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• pp.191-198
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• 2022

Zirconia and titanium alloys, which are mainly used for dental implant materials, have poor osseointegration and osteogenesis abilities due to their bioinertness with low bioactivity on surface. In order to improve their surface bioinertness, surface modification with a bioactive material is an easy and simple method. In this study, akermanite (Ca₂MgSi₂O₇), a silicate-based bioceramic material with excellent bone bonding ability, was synthesized by a solid-state reaction and investigated its bioactivity from the analysis of surface dissolution and precipitation of hydroxyapatite particles in SBF solution. Calcium carbonate (CaCO₃), magnesium carbonate (MgCO₃), and silicon dioxide (SiO₂) were used as starting materials. After homogeneous mixing of starting materials by ball milling and the drying of at oven, uniaxial pressing was performed to form a compacted disk, and then heat-treated at high temperature to induce the solid-state reaction to akermanite. Bioactivity of synthesized akermanite disk was evaluated with the reaction temperature from the immersion test in SBF solution. The higher the reaction temperature, the more pronounced the akermanite phase and the less the surface dissolution at particle surface. It resulted that synthesized akermanite particles had high bioactivity on particle surface, but it depended on reacted temperature and phase composition. Moderate dissolution occurred at particle surfaces and observed the new precipitated hydroxyapatite particles in synthetic akermanite with solid-state reaction at 1100℃.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.2
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• pp.104-113
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• 2009

Gyeong Po in Gangneung is highly recognized as a scenic area that is home to twelve traditional pavilions which are still in existence today. Since the modification of the Natural Park Act in 2007, there has been serious concern about the regulation of the heights of buildings surrounding Gyeong Po. In light of this, the present study aims to provide some guidelines for the regulation of building height in the modified Natural Park Act on the basis of investigations of landscape characteristics of Gyeong Po and the psychological influences of changing building heights. The analysis of the view from the pavilions located around Gyeong Po Lake indicated that the strategic landscape control points were Gyeong Po Dae and Bang Hae pavilions in terms of landscape management. These two landscape control points were considered as points from which people could view the greatest part of the landscape surrounding Gyeong Po Lake. The results of a preference analysis revealed that the views from Gyeong Po Dae to Juk Do were of relatively higher preference than the view from Bang Hae pavilion. This finding emphasized the importance of landscape management in Juk Do and its surroundings. A factor analysis resulted in three factors including attractiveness, tranquility, and orderliness. A comparison of the magnitude of influence of these three factors showed that the order of influence to preference was: attractiveness>tranquility>orderliness. These results highlight the need to introduce landmarks or unique buildings into the areas because the panoramic views of Gyeong Po Lake are relatively flat as lake views go. There should also be a variety of skylines harmonizing with the natural landscapes and landscape management for building groups, rather than individual building control, to enhance tranquility. Analysis of the psychological effects of building height suggests that, regardless of view points, preference was split at a 30 meter building height. This was indicative that viewer preference would drop when building heights are controlled to allow heights over 30 meters. The present study was not able to take varying view points and story heights into account. A more detailed study considering building types, the arrangement of buildings and the number of building stories is needed for effective landscape management in the Gyeong Po Dae area.

• Development and Reproduction
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• v.12 no.1
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• pp.1-8
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• 2008

Specific protocols to increase the differentiation of neuronal cells from embryonic stem (ES) cells have been well established, such as retinoic acid induction and lineage selection of neuronal cells. For the neuropathological studies, ES-derived neurons (ES neurons) must show normal physiological characteristics related to cell death and survival and should be maintained in vitro for a sufficient time to show insults-specific cell death without spontaneous death. When mouse ES cells were plated onto astrocytes monolayer after retinoic acid induction, most ES cells differentiated into neuronal cells, which were confirmed by the presence of specific neuronal markers, and the cultures were viable for at least four weeks. When these cultures were examined for vulnerability to glutamate excitotoxicity, ES neurons were vulnerable to excitotoxic insults mediated by agonist-specific receptors. The vulnerability to excitotoxic death increased with developmental age of ES neurons in vitro. Specific receptors for Neurotrophin and GDNF family ligands were present in ES neurons. GDNF and NT-3 could modulate the survival and excitotoxic vulnerability of ES neurons. The vulnerability and resistance to toxic insults, which are essential requirements of model culture systems for neuropathological studies, make ES neurons to a useful model culture system. Especially ES cell are highly amenable to genetic modification unlikely to primary neuronal cells, which will give us a chance to answer more complicated neurophysiological questions. Recently there was an outstanding attempt to explore the cellular toxicity using human ES cells (Schrattenholz & Klemm, 2007) and it suggested that ES cells could be a new model system for neurophysiological studies soon and go further a large-scale screening system for pharmacological compounds in the future.