• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.109-116
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• 2002

Through the increment of requirement for group oriented communication services, on the open network, the multicast infrastructure has become a widely discussed researching topic. However the research of the security properties that safety, efficiency and scaleability in a multicast structure, has not been enough. In this study, we discuss conventional multicast key management structures and propose a scalable secure multicast key management structure based on PKI(Public Key Infrastructure), IPSec, domain subgroup and structural two mode scheme. Also we certify to the usability of new proposed scheme from comparing it with conventional schemes in the part of safety, efficiency and scaleability.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.67-75
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• 2004

In this paper, we design an authentication model based mobile PKI (Public Key Infrastructure). The authentication mood consists of Root-CA Home-network agent and Foreign-network agent. CA will going to gave the delegation ticket to Home-Agent or Foreign-Agent when they request. The authentication mode information security is various characteristic more then high speed, mobile network and low cost more then previous structure of assure information security.

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1295-1309
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• 2007

A wireless access point is used for all communications in the infrastructure mode wireless home networking, including communication between mobile nodes in the same service area. When a mobile station in the infrastructure mode wireless home networking moves into a dead zone, the communication between the mobile station and the access point is disconnected. To solve this problem, the existing wireless home network platforms focus on the ad hoc mode wireless home networking. However, the performance of an ad hoc network is poorly decreased when the number of mobile participating in the ad hoc network increases. In addition, although the ad hoc routing technique is necessary to support seamless communication of mobile nodes, the existing routing protocols, such as AODV and DSR, do not consider that a wireless channel state could affect performance significantly. Therefore, we propose a wireless home networking platform based on the ESCOD (End-to-end Seamless multi-hop COnnection based on Dual network mode) technique incorporating the VLR (Virtual Link Routing) scheme that supports end-to-end seamless connections. Extensive experiments show that the proposed wireless home networking platform incorporating the VLR scheme outperforms wireless home networking platforms based on the AODV and the DSR routing protocols respectively in terms of low packet transmission failure rate, fast packet transmission time, high TCP performance, and a wider coverage area of wireless home networks.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.257-260
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• 2005

In this paper we design and evaluate Hybrid Wireless Mesh Networks on IEEE 802.11-based network. So we analysis the CWMNs and BWMNs to integrate them. The CWMNs of Ad hoc Mode cannot be directly connected to the BWMNs of Infrastructure Mode because they have different frame types. We propose the new effective HWMNs scheme using DYMO than OLSR protocol for the inter-operability and the mobility

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.2
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• pp.94-100
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• 2010

The reliable multicast MAC (Medium Access Control) protocol is needed to guarantee the recipients' nonerroneous reception of the multicast data frames, which can be transmitted by the AP (Access Point) in infrastructure mode IEEE 802.11 wireless LANs. Enhancing the BMMM (Batch Mode Multicast MAC) protocol, in the literature, the connectivity-based reliable multicast MAC protocol was proposed to reduce the RAK (Request for ACKnowledgement) frame transmissions and enhance the multicast MAC performance. However, the number of necessary RAK frame transmissions increases as the number of multicast recipients increases. To alleviate the problem of the larger number of RAK frame transmissions with the larger number of multicast recipients, we propose the clustering algorithm for partitioning the recipients into a small number of clusters, so that the recipients are connected each other within the same clusters. Numerical examples are presented to show the reliable multicast MAC performance improvement by the clustering algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.124-126
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• 2004

본 논문은 CAM(Constant Awake Mode), 및 PSM(Power Saving Mode)을 지원하는 IEEE 802.l1b[1] Infrastructure 환경에서 전송 프로토콜이 이동기기의 WNIC(Wireless Network Interface Card) 에너지 소비에 미치는 영향을 분석하고 단위 시간 동안 전송되는 데이터 양에 기반한 IEEE 802.l1b WNIC 에너지 모델을 제안한다. 제안하는 에너지 모델은 IEEE 802.l1b 환경에서 CAM 및 PSM 모드를 사용할때, 실제 측정한 값을 기반으로 설계되었다. 제안된 에너지 모델은 실험을 통하여 정확성을 검증하고, IEEE 802.l1b를 기반으로한 저전력 통신 관련 연구에서 시뮬레이션 시 사용 가능한 에너지 모델임을 밝힌다.

• Journal of information and communication convergence engineering
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• v.18 no.4
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• pp.245-253
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• 2020

The human body and nervous system transmit information through electric charges. After the electric charge transmits information to the brain, we can feel pain, numbness, comfort, and other feelings. Electric therapy is currently used widely in clinical practice because the field of examination is more representative of electrocardiogram, and in the field of treatment is more representative of electrotherapy. In this study, we design a system for neurophysiological therapy and conduct parameter calculation and model selection for the components of the system. The system is based on a discontinuous conduction mode (DCM) boost circuit, and controlled and regulated by a single-chip microcomputer. The system does not only have a low cost but also fully considers the safety of use, convenience of the human-computer interface, adjustment sensitivity, and waveform diversity in the design. In future, it will have strong implications in the field of electrotherapy.

• Journal of Korean Society of Transportation
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• v.31 no.1
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• pp.15-24
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• 2013

To accommodate urban concentration of population, multi-purpose super-tall buildings have been introduced, but they induce many travel demands causing regional traffic problems. While several travel demand management policies such as transit promotion or parking limits are presented to alleviate such problems, transportation infrastructure are still insufficient to meet high demands. In this study, super-tall buildings are categorized by scale and purpose, then mode-specific derived demand is estimated using modal share of each category. Optimal transportation infrastructure level is determined by condition-based average changing amount yielded by street network delay (in case of road) or the number of transit routes (in case of transit).

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.211-211
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• 2022

The marketization reform from the open-door policy in 1978 was not only booming export-oriented industries with foreign investment but also expanding the role of private actors in the Chinese water sector. Private Sector Participation (PSP) has become an important element in developing urban infrastructure by providing better services with advanced facilities. The rapid development of PSP-driven urban water infrastructure in China has a positive impacted on Chinese economic development, particularly in coastal areas. PPPs in some coastal areas have successfully spread out over China since China applied the first Build-Operate-Transfer (BOT) mode in the water sector in the early 1990s. The market-oriented water and wastewater, Public-Private Partnership (PPP) mechanism in the initial period of China has been transformed into a state-dominated PPP mechanism. The development pattern of the water and wastewater PPPs in China has been divided in four stages: the first period from 1984 to 2002, the second period from 2003 to 2008, the third period from 2009 to 2014, and the last period after 2015. The study aims to investigate the successful process of water and wastewater PPPs in local areas through five socioeconomic elements: export-oriented economic strategy, urbanization, cheap land policy, infrastructure investment, and water issues and climate change. In addition, the study focuses on analyzing the extent to which the Chinese government re-asserted its control over the PPP mechanism by classifying five elements in three different development Phases from early 2000 to 2020. The Jiangsu Province in the estern coastal area has actively invited PPP projects in the water and wastewater sectors. The successful introduction and rapid growth of PPPs in the urban water infrastructure has made the province an attractive area for a foreign investor.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.165-173
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• 2014

The method of emission inspection for Heavy-duty diesel vehicles has been engine speed type Lug-down 3mode. This method could bring damage to decrepit vehicles under high speed and high load condition and it could not apply the driving pattern on the road. For these reasons, this study has started to create new emission inspection which is appropriate for Korea's road infrastructure. KD 147 would be applied to light-duty diesel vehicles from july 2010 after model operations. Therefore, this study has investigated new emission inspection system for heavy-duty diesel vehicles, except for light-duty diesel vehicles. In consideration of domestic conditions to meet the new load test method in this study, the Lug-down3 mode vehicle speed method was developed for the first time in korea.