• The KIPS Transactions:PartD
• /
• v.10D no.3
• /
• pp.521-530
• /
• 2003

Various multimedia application services have been developed with techniques of high speed networks and computer. Among these services, a video-conference system over internet is useful and important, and its standardization has been shown in ITU-T H.323 and IETF SIP. H.323 standardization is currently used in many products, but two standardizations will coexist for a long time. Since the interoperability is needed between two standardizations, H.323-SIP gateway is developed for it. In audition, a video-conference system supporting two standardizations is necessary to be developed. We have implemented the video-conference terminal supporting both ITU-T H.323 and IETF SIP standardizations over internet. The system implementation has been designed using the common modules of two standardizations maximally, and the interoperability among different systems is satisfied through experiments.

• Korean Journal of Cognitive Science
• /
• v.16 no.4
• /
• pp.243-254
• /
• 2005

Pulfrich effect implies the possibility that motion information is processed by the system that processes depth information, and this possibility by supported by various neurophysiological studies. Although Pulfrich effect is processed by the system that processes binocular disparity, the representative depth information, there has not been a psychophysical research to determine the characteristics of the interaction between Pulfrich effect and binorular disparity using a stimulus containing the two information sources. Present research examined the characteristics of the interacation between Pulfrich effect and binocular disparity by nenuring the depth and rotation direction of a rotating cylinder comprised of random dots under two different conditions: 1) consistent rendition where the Pulfrich effect and binocular disparity depth the depth and rotation direction of the cylinder in a consistent manner 2) inconsistent rendition where they did not. , The perceived depth of the cylinder in the consistent condition was larger than that in disparity/Pulfrich effect only condition. Interestingly, the perceived rotation direction of the cylinder in the inconsistent condition was modulated by the relative strength of the disparity and the Pulfrich effect. These results imply that binocular disparity and Pulfrich effect are processed by a common neurophysiological methanism.

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

• Journal of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.483-494
• /
• 1988

The adsorption behavior of aromatic acids on Amberlite XAD-4 resin was investigated by measuring the distribution coefficient by batch method. The adsorption of solutes on XAD-4 was affected by the several factors such as, analyte concentration, the pH of solution and concentration of pairing ion. The enhanced adsorption of solutes on XAD-4 in the presence of tetraalkylammonium salt as an ion pairing reagent, referred to as ion interaction, was suggested to follow a double layer model where the pairing ion occupies a primary layer at the adsorbent while the solute anion and other anions in the system comlpete for the secondary layer. Therefore, the ability of an ion pairing reagent to enhance solute adsorption depended significantly on the type and concentration of counter-ion and co-anion accompanying the ion pairing reagent or salt used for ionic strength control. In addition, a good linear relationship between the logarithm of capacity factors measured by batch and elution method as a function of the concentration of ion pairing reagent and methanol can be used to predict the retention in elution method on the basis of capacity factors measured by batch method.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.163-168
• /
• 2011

The variations of molar conductivity of various surfactants such as sodium caprylate, sodium laurate, sodium palmitate, sodium stearate, sodium oleate, sodium dodecyl sulphate, and lithium dodecyl sulphate with concentrations of the surfactants for each of the solutions consisting of mixtures of varying concentrations of N-methyl acetamide in water at constant temperature of $30{\pm}0.2^{\circ}C$ were studied. The critical micelle concentration (CMC) for each surfactant is measured. It is found that the CMC values in mixtures of N-methyl acetamide and water solutions of various surfactants are lower than the CMC values in water, and the driving force for micelle formation correlates with solvophobicity. The surfactant-solvent interactions that drive amphiphilic self-organization in N-methyl acetamide in water are discussed. Thermodynamic parameters were evaluated for micellar system to explain the results.

• Polymer(Korea)
• /
• v.29 no.1
• /
• pp.1-7
• /
• 2005

Interpenetrating polymer network (PN) is a mixture of network polymers. The characteristics of IPN material is the control of morphology during the IPN synthesis. By controlling the relative kinetics of chemical reaction (as well as gellation) and phase separation, the morphology of IPN can be controlled to obtain materials with nano-scale domain and also the co-continuous phase. Other important advantage is the fact that the morphology is permanent due to the presence of the physical interlocking between the networks. The combination of hydrophilic polyurethane and hydrophobic polystyrene in IPN form provides enhanced blood compatibility due to the co-existence of the hydrophilic and hydrophobic domains in nano-scale on the surface. The reaction temperature, reaction pressure and the degree of crosslinking were varied during the IPN synthesis and the morphology and blood compatibility of the resulting IPN materials were studied.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.1
• /
• pp.58-71
• /
• 2019

This paper proposes architecture of a cognitive radio engine platform and the allowable frequency channel reasoning method that enables acquisition of the allowable channels for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary radio frequency to ensure that multiple wireless networks for different military wireless devices coexist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper presents the allowable frequency channel reasoning method based on cognitive radio engine for realizing DSA(Dynamic Spectrum Access) as an optimal available frequency channel. To this end, a case-based allowable frequency channel reasoning method for cognitive radio devices is proposed through modeling of primary user's traffic status and calculation of channel occupancy probability. Also through the simulation of the performance analysis, changing rate of collision probability between the primary users' occupancy channel and the available channel acquisition information that can be used by the cognitive radio device was analysed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.2
• /
• pp.255-260
• /
• 1996

증편반죽의 발효에 따른 해면상의 조직(망상구조)형성능의 mechanism을 조사하기 위하여 반죽의 구성성분의 경시적 물성 및 효소(diastase 및 protease) 활성의 변화, 구성 전분 분획의 glucose chain length 변화 및 1% SDS에 의해서 용출되는 단백질 분획의 변화에 대해서 검토하였다. 발효가 진행됨에 따라 증편반죽의 pH는 감소한 반면 점성 및 부피는 발효경과 10시간가지 증가하다가 그 이후로는 약간 감소하는 경향을 보였다. 발효의 진행과 더불어 diastase의 활성은 증가하였으며, 쌀전분 분획 중 amylose의 함량은 약간 감소하였다. 그리고 전분분자의 $\alpha-1,6-glucoside$ 결합을 isoamylase(debranching enzyme)로 가수분해시킨 후 Sephadex G-75를 이용한 chromatogram 분석에 의하면 쌀가루 전분 분획과 증편반죽 전분 분획의 glucose chain length 분포는 거의 유사하지만 발효가 진행됨에 따라 중합도가 낮은 부분이 우선적으로 diastase의 작용을 받은 것이라고 생각되어진다. 한편, 발효가 진행된에 따라 protease의 활성은 증가하고 있었음에도 불구하고 증편반죽의 당에 의한 단백질 분획의 고분자화가 Suprose CL-12 column chromatogram 상에서 관찰되었는데, 이것은 아마도 발효과정 중 증편반죽에 공존하는 미생물들의 발효산물인 당질(gum질)을 매개로 한 단백질 분자의 회합에 의한 결과라고 생각되어진다. 따라서 이러한 결과를 미루어 볼 때 증편반죽의 망상구조 형성능은 발효과정 중 일어나는 당과 단백질간의 상호작용에 의한 결과라 생각되어진다.

• Journal of the Korean Institute of Educational Facilities
• /
• v.3 no.2
• /
• pp.25-35
• /
• 1996

This study is to find countermeasures of facility space according to the development of new educational program and the opening of education market from the renewal of existing facilities. The renewal is consider as the worldwide trend for enhancing added value of the facilities in economic side of educational facilities as well as educational contents. This study selects six from 94 elementary schools in Kwangju-city to examine our educational conditions, understand using conditions and recognition of existing space and possibility of the recycle. The hypothesis that recognition of existing facility space in school may be varied according to physical conditions of children is made in four sides, six elements and two trends are extracted and then life pattern, size, sense of materials and cognition of three types of passage space are analyzed. Accordingly, this study obtains such results that passage space is life space having strong place concept and there is the possibility of renewal of existing school building facilities corresponding to multipurpose of school facilities.

• Proceedings of the Korea Contents Association Conference
• /
• 2011.05a
• /
• pp.519-520
• /
• 2011

웹 3D 환경을 기반으로 하고 있는 가상현실 분야의 연구들은 대부분 가상공간을 구축해놓고 사용자들로 하여금 가상공간을 항해함으로서 각종 정보들을 시각적으로 확인할 수 있는 정도의 기본 기능만을 지원하고 있는 것들이 많다. 본 논문은 이와 같은 기존 연구들의 단조로움을 보완하기 위한 하나의 방법으로 실제 캠퍼스 건물 하나를 그대로 가상공간에 구축하고 인공지능을 가진 아바타로 하여금 사용자가 필요로 하는 건물 정보를 시청각 데이터와 아바타의 동작으로 직접 보여줄 수 있는 캠퍼트 건물 정보 안내 시스템을 설계 및 구현하였다. 특히 인공지능을 가진 아바타는 사용자와 상호작용을 하도록 설계되었으며, 가상공간은 현실세계에서는 제공해줄 수 없는 각종 정보를 다양하게 제공해줄 수 있다는 장점을 최대한 활용하였다. 이를 사용자 인터페이스로 구축하여 논리적 타당성과 유효성을 검증하기 위해 실험적인 적용을 시도하고자 한다. 향후에는 본 시스템을 캠퍼스 전체 건물로 확장하여 현실과 가상이 공존하는 증강현실의 기능을 가진 캠퍼스 건물 정보 안내 시스템을 구축할 수 있을 것이다.