• Proceedings of the Korean Geotechical Society Conference
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• 2002.06a
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• pp.57-76
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• 2002

As piling works in urban area increasing, SIP which is low noise & vibration piling method is taking place of driven pile which has good bearing charateristics and economics. Since SIP has been used for more than 15 years and it's application is increasing year by year, however, accurate analysis of bearing mechanism of SIP is not enough. So the design of SIP is much more conservative than driven pile. This paper is aimed to analyse the bearing charateristics of 103 SIPs constructed in Korea to give rational design criteria. Research result shows that bearing capacity of SIP is 40% lower than that of driven pile and conservative Meyerhof(equation omitted) method produced closer result to load test results than other design method. And this result show that to use optimised design criteria for the economic SIP design, quality control criteria must be settled down to produce high in-situ bearing capacity.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1285-1288
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• 2010

SIP 프로토콜은 멀티미디어 통신 세션을 생성, 삭제, 변경할 수 있는 프로토콜로 높은 간결성, 확장성 등 장점을 가지고 있다. 최근 인터넷전화의 대부분이 SIP 프로토콜을 사용하는 등 SIP 프로토콜의 사용이 많이 보편화 되었으나 그만큼 보안에 대한 위협 또한 중요한 문제가 되고있다. SIP는 응용계층 프로토콜로, 기존의 IP기반 보안 기술로는 공격 탐지/차단에 한계가 있을 수 있어 SIP 전용의 보안 기술 및 장비의 개발이 필요하다. 본 논문에서는 SIP 트래픽의 응용계층 정보 통계를 통하여 DDoS 공격트래픽 행위 특성을 분석하고 이를 정상 트래픽과 구분, 탐지하는 탐지 기법을 제안한다. 제안된 기법은 자체 테스트 망 구축과 SIP DDoS 공격 에뮬레이션을 통해 검증한다.

• The Journal of the Korea Contents Association
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• v.8 no.2
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• pp.67-73
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• 2008

Recently, due to the rapid advances of mobile communication, multimedia service can be provided by mobile devices. Cellular network tends to uses SIP as a call setup protocol in order to provide various multimedia service to consumers. Cellular network holds the characteristic of higher BER(Bit Error Rate), narrower bandwidth than the wired network. The value of SIP RTI(Retransmission Time interval) based on the wired network decreases a network efficiency and increases a call setup delay over cellular network. By using NS-2 simulator, we show new SIP RTI value adequate over cellular network. We design and implement home network by using the modified SIP that is suitable for cellular network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.331-334
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• 2002

According as internet service diffusion is popularized by internet user's increase, internet telehpony technology is becoming main issue of Internet Service Providers. Standardization issue about technologies related VoIP is discussed keeping in step on market's fast change and request in IETF. Specially, Standardizaiton is working through discussion on MMUSIC WG, SIP WG, SIPPING WG about SIP that is proposed by the alternative of ITU-T's H.323. Therefore in this Paper, introduce SIP standard that is established through several reconsideration revision works, and examine about IETF's trend for SIP based internet telephony service.

• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.51-60
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• 2003

As piling works in urban area are increasing, SIP which has low noise & vibration piling method takes the place of driven pile which has good bearing charateristics and is economical. Although SIP has been used far more than 15 years and it's use is increasing year by year, accurate analysis of bearing mechanism of SIP is not enough. So the design of SIP is much more conservative than driven pile. This paper is aimed at analysing the bearing charateristics of 103 SIPs constructed in Korea to give rational design criteria. Research result shows that bearing capacity of SIP is 40% lower than that of driven pile and conservative Meyerhof(20$\bar{N}_b'A_b$) method produced closer result to load test results than any other design method. And this result shows that in order to use optimised design criteria for the economical SIP design, quality control criteria must be settled down to produce high bearing capacity.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.55-64
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• 2007

Behind the popularity of VoIP in these days, it may present significant security challenges in privacy and accounting. Authentication and message encryption are considered to be essential mechanisms in VoIP to be comparable to PSTN. SIP is responsible for setting up a secure call in VoIP. SIP employs TLS, DTLS or IPSec combined with TCP, UDP or SCTP as a security protocol in VoIP. These security mechanisms may introduce additional overheads into the SIP performance. However, this overhead has not been understood in detail by the community. In this paper we present the effect of the security protocol on the performance of SIP by comparing the call setup delays among security protocols. We implement a simulation of the various combinations of three security protocols and three transport layer protocols suggested for SIP. UDP with any combination of security protocols performs a lot better than the combination of TCP. TLS over SCTP may impose higher impact on the performance in average because TLS might have to open secure channels as the same number of streams in SCTP. The reasons for differences in the SIP performances are given.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.797-804
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• 2009

Recently, SIP(Session Initiation Protocol) is used to set up and manage sessions for multimedia applications such as VoIP(Voice over IP) and IMS(IP Multimedia Subsystem). However, because SIP operates over the Internet, it is exposed to pre-existed internet security threats such as service degradation or service disruptions. Multimedia applications which are delay sensitive even suffers more from the threats mentioned above. The proposed methods so far to detect SIP INVITE flooding are CUSUM(Cumulative Sum), Hellinger distance and adaptive threshold, but among methods only take normal state into consideration. So, it is not capable of adapting the condition of the network congestion which are dynamically changing. In this paper, SIP INVITE flooding detection algorithm considering network congestion which enables efficient detections of such attacks is proposed. The proposed algorithm is expected to detect other types of attacks such as BYE and CANCEL more precisely compared to other methods.

• Journal of Pharmaceutical Investigation
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• v.30 no.4
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• pp.235-239
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• 2000

Ipriflavone (3-phenyl-7-isopropoxy-4H-1-benzopyran-4-one, IP) is a well-known antiosteoporotic drug with poor bioavailability. In the previous study, we reported that the IP formulation prepared by spray-drying method with polyvinylpyrrolidone (PVP) (SIP) was very effective in improving the bioavailability of IP. In this study, we examined the effects of molecular weight and mixture ratios of PVP to IP on the systemic absorption of IP following oral administration of SIP at a dose of 50 mg/kg to rats. In the effect of molecular weight, the Cmax of spray-dried IP with PVP K30 (SIP-K30) was significantly higher than those of spray-dried IP with PVP 360 (SIP-360), spray-dried IP with PVP K90 (SIP-K90), and spray-dried IP with PVP K17 (SIP-K17) (p<0.05). The AUC of SIP-K30 was about 2, 3, and 5.5 times higher than those of SIP-360, SIP-K90, and SIP-K17, respectively. The AUC value of SIP-K30 was significantly greater than those of SIP-K17 and SIP-K90 (p<0.05) except for SIP-360. In the ratio of PVP K30 to drug, the $C_{max}$ and the AUC value of 3 : 7 IP-PVP solid dispersion were similar to those of 5 : 5 IP-PVP and significantly higher than those of the other solid dispersions (p<0.05). It was concluded that the spray-dried IP with PVP K30 at the ratio of 3:7 (w/w) was the best formulation for improving the bioavailability of IP.

• Journal of the Korean GEO-environmental Society
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• v.5 no.3
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• pp.5-15
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• 2004

SIP has been widely used as a low noise and vibration piling method in Korea. But the quality control of SIP was not properly settled down and field workers did not fully understand the principle of SIP method. So not a less troubles were raised at construction site and bearing capacity was not fully mobilized. To settle these problems, Korea National Housing Corporation amended the construction and load test criteria of SIP in 2002. After load tests on the SIPs installed in field according to the new criteria, we found that the bearing capacity in field vs the design load ratio increased and bearing characteristics was enhanced than that installed by the former criteria. To consider the enhanced bearing characteristics in the pile design and determine the adequate design criteria, this paper analyzed the accuracy of design criterion which were commonly used in Korea comparing with the load test results. Analysis result shows that Meyerhof criteria(1976) properly simulates the bearing capacity of SIP installed by the new construction and load test criteria.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.73-80
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• 2007

This paper presents an approach to support dynamic QoS(Quality of Service) requirements of largely emerging SIP(Session Initiation Protocol) multimedia applications in broadband access networks. The topology of QoS-enabled broadband access networks and its operational model to support SIP QoS are firstly suggested. And then the procedures to bind QoS-enabled SIP signaling into an IP QoS mechanism are presented. In this paper, DiffServ-based IP QoS architecture is deployed due to the complexity problem of the other IntServ architecture, and COPS(Common Open Policy Service) and COPS-PR protocol based signaling mechanisms are used to support dynamic DiffServ QoS, correspondent with dynamic SIP QoS. The broadband access network is assumed to support rapidly expanding Metro Ethernet 802.1 D/Q QoS, and how to translate SIP QoS parameters into IP DiffServ classes and DiffServ classes into 802.1 D/Q QoS parameters is also presented in this paper.