• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1493-1500
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• 2004

Today's Commercial security server system which provide secrecy, integrity and availability may still be vulnerable to denial-of-service attacks. Authentication system whith use a public key cryptography and process RSA encryption is relatively slow and the slowness has become a major security threat specifically in service flooding attacks caused by authentication requests. The service flooding attacks render the server incapable of providing its service to legitimitive clients. Therefore the importance of implementing systems that prevent denial of service attacks and provide service to legitimitive users cannot be overemphasized. In this paper, we propose a puzzle protocol which applies to authentication model. our gradually strengthening authentication model improves the availability and continuity of services and prevent denial of service attacks and we implement flooding of service tolerance system to verify the efficiency of our model. This system is expected to be ensure in the promotion of reliability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1912-1921
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• 2015

In this paper, we introduce a testbed for testing the RF energy transfer technology in the Internet of Things (IoT) environment, and provide experimental results obtained by using the testbed. The IoT environment considered in this paper consists of a power beacon, which is able to wirelessly transfers energy via microwave, and multiple sensor nodes, which makes use of the energy received from the power beacon. We have implemented the testbed to experiment the RF energy transfer in such IoT environment. We have used off-the-shelf hardware components to build the testbed and have made the tesbed controlled by software so that various energy and data transmission protocol experiments can easily be conducted. We also provide experimental results and discuss the future research direction.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.225-232
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• 2008

Overload vehicles operate damage to road, bridge, and then increasing in maintenance and repair cost because structures are reduced durability. The existing regulation systems have many problems and need coping measure. Therefore, this paper organized Ubiquitous sensor network system for development of intelligent auto overload vehicle regulation system about high speed vehicles, also axial load WIM sensor was selected by indoor experiment through wireless protocol. And we examined possibility U-load auto overload vehicle regulation system through experiment of the transmission and reception distance. If this system will apply to road and bridge, might be effective for economy and convenience through establishment of U-IT system. And high speed vehicle that was amalgamate IT technology and existing overload regulation problems, also tested wireless sensor for USN organization. This experiment aim to organize system interface for user through perfection man-less, wireless system of Internal/External Network from high speed WIN sensor with USN organization. Accordingly, it is necessary experimentation through Test Bed for constitution External network and application of actually regulations using WCDMA/HSDPA.

• IMMUNE NETWORK
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• v.13 no.1
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• pp.34-41
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• 2013

Interleukin-18 (IL-18) has been known to induce interferon-${\gamma}$ (IFN-${\gamma}$) production and promote Th1 immunity. Although mammalian IL-18 has been characterized in great detail, the properties and application of chicken IL-18 remain largely uninvestigated as of yet. In this study, we evaluated the immunomodulatory properties of Salmonella enterica serovar Typhimurium expressing chicken interleukin-18 (chIL-18) on immune responses induced by avian influenza (AI) and Newcastle disease (ND) vaccines. After oral administration of S. enterica serovar Typhimurium expressing chIL-18, chickens were vaccinated intramuscularly with the recommended dose of either inactivated AI H9N2 vaccine or ND (B1 strain) vaccine. Chickens receiving a primary vaccination were boosted using the same protocol 7 days later. Humoral and cell-mediated immune responses were evaluated in terms of HI antibody titers and proliferation and mRNA expression of IFN-${\gamma}$ and IL-4 of peripheral blood mononuclear cells (PBMC) in response to specific antigen stimulation. According to our results, oral administration of S. enterica serovar Typhimurium expressing chIL-18 induced enhanced humoral and Th1-biased cell-mediated immunity against AI and ND vaccines, compared to that of chickens received S. enterica serovar Typhimurium harboring empty vector. Therefore, we conclude that our proposed vaccination regimen using inactivated AI and ND viruses along with oral administration of S. enterica serovar Typhimurium expressing chIL-18 may provide a novel approach in protecting chicken from currently circulating AI and ND virus strains.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.373-383
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• 2016

With mobile-epoch and emerging of Fin-tech, Bio-recognition technology utilizing bio-information in secure method has spread. Specially, In order to change convenient payment services and transportation cards, the combination of biometrics and mobile services are being expanded. The basic concept of authentication such as access control, IA&A, OpenID, OAuth 1.0a, SSO, and Biometrics techniques are investigated, and the protocol stack for security API platform, FIDO, SCIM, OAuth 2.0, JSON Identity Suite, Keystone of OpenStack, Cloud-based SSO, and AIM Agent are described detailed in aspect of application of AIM. The authentication technology in domestic and foreign will accelerate technology development and research of standardization centered in the federated FIDO Universal Authentication Framework(UAF) and Universal 2 Factor Framework(U2F). To accommodate the changing needs of the social computing paradigm recently in this paper, the trends of various authentication technology, and design and function of AIM framework was defined.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.167-173
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• 2006

The embryos of marine bivalves have been commonly used in bioassays for quality assessments of marine environments. Although several standard protocols for the developmental bioassay of bivalves have been proposed, only a few trials for application of these protocols in environmental assessments or for the development of a new protocol with Korean species have been conducted. As such, there is a strong need to establish standard bioassay protocols with bivalves commonly found in Korean waters. To determine the sensitivity of Mytilus galloprovincialis to establish a standard bioassay, their fertilized eggs were exposed to six metals (Ag, Cd, Cr, Cu, Ni, and Zn). The order of biological impact was Ag > Cu > Ni > Zn > Cr > Cd and their lowest observed effective concentration were 5, 16.4, 25.4, 142, 187 and 1,500${\mu}g/l$, respectively. The proportion of normal larvae appeared to decrease linearly with the logarithm of each toxicant concentration within the tested range. The average values of median effective concentrations $(EC_{50})$ from the triplicate experiments for Ag, Cd, Cr, Cu, Ni, and Zn were 6.8, 1,797, 786, 16.6, 68.1, and 139.2${\mu}g/l$, respectively. There was a more than 100-fold difference in $EC_{50}$ values of Cu and Cd. The value of $EC_{50}$ or median lethal concentration of Cu was within the range observed for other bivalve developmental bioassays. The overall sensitivity of M. galloprovincialis in the present developmental bioassay was also similar to that of other marine organisms commonly used in aquatic bioassays (e.g. sea urchins, oysters). Hence, the bioassay using the embryo of M. galloprovincialis is considered to be a useful tool to monitor and evaluate the quality of marine aquatic environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.210-217
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• 2005

With rapid advance in wireless communication technologies, many researches are conducted for providing Internet data services while users are roaming around. Efficient management of mobility of mobile nodes is essential as the use of real-time application program grows. In this paper, we propose a multicast-based localized mobility support scheme in IPv6 networks. The proposed scheme utilizes a class of multicast routing protocol for the localized mobility support. Features of the proposed scheme are use of join to a multicast group and leave from that group to localize binding update information and provision of an extended multicast group management mechanism to reduce leave latency. The results of simulation show that the proposed scheme out-performs Mobile IPv6 and Hierarchical Mobile IPv6 in UDP and TCP traffic performance and in wasted bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1348-1356
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• 1991

The need for MAN(Metropolitan Area Network)has been increased by demands for high performance comuter communication. According to the definition of MAN by IEEE 802.6 MANs have diameter of about 50km, bandwidth of more than 1Mbps, and limited delay, Because optical fibers have unique characteristics that make them attractive for the implementation of MANs several fiber optic networks suitable for MAN application have been proposed. Those networks have drawbacks such as unlimited delay, many processing nodes and limited number of stations. Also IEEE 802.6 proposals and oters improved networks were proposed, but they have complicated access procedures and data buffering and difficulties in implementation. This paper descrives the design of Fiber Optic Metropolitan Area Network in Seoul(Seoul FOMAN) to overcome the drawback, Seoul FOMAN is hierarchical MAN and designed based on the topology of 43 end offices in Seoul. We propose MAN topology, proper access protocol and analyze the performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1167-1176
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• 2014

In this paper, a relay communication scheme for enhancing the WiMedia network performance by device's mobility is proposed. WiMedia protocol is suitable for the application that supports the real-time multimedia service in Ship Area Network since it supports high speed data transfer. However, the device's mobility is caused the dramatic change of link state and network topology, and is occurred the degradation of network performance. Therefore, a relay communication scheme for WiMedia network is proposed in this paper. The proposed technique can intelligently treat the change of link state, and solve the degradation of network performance.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.165-176
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• 2015

Clock or time synchronization protocol is one of the crucial factors that could determine the quality of the communication. With the rapid development of the network technology, more robust clock synchronization algorithm is required. IEEE 1588 is one of the possible solutions for a robust clock synchronization algorithm; however, there are still some challenges that need to be concerned in IEEE 1588 in term of reducing and stabilizing the PDV value. This survey paper shows several solutions that could improve the performance of IEEE 1588, including modifying the PTP message transmission, optimizing PTP method, filtering techniques, and using the hardware timestamp instead of application layer timestamp, and so on. Despite the improvement that is created with these techniques, the clock synchronization algorithm is still an open issue in the network communication.