• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.839-841
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• 2013

LTE 환경에서 초기 망 접속을 위한 UE와 MME 간의 사용자의 정보에 대한 인증을 위하여 IMSI, GUTI 등의 정보를 요청, 승인 하게 된다. 이 과정에서 사용자의 유일한 식별값인 IMSI를 새로운 MME로 전송하는 경우 별도의 암호화 과정 없이 평문의 IMSI 값이 전송되어진다. 이로 인하여 평문으로 전송되는 IMSI값에 대한 보안 위협이 발생하고, 이로 인하여 사용자 추적, 단말 추적 등 사용자의 Privacy에 대한 침해 및 가장 공격 등이 발생된다. 본 논문에서는 UE와 MME간 초기 통신과정에서 IMSI에 대한 암호화를 통하여 안전성 강화에 대한 제안을 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6C
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• pp.645-650
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• 2006

GSM(Global System for Mobile communications) provides mobile users with portability and convenience as the most popular standard for mobile phones in the world. However, GSM system has the problem that can't normally authenticate a user by the exposure of IMSI(International Mobile Subscriber Identity) of Ms(Mobile station) during the user authentication procedure. In this paper, we propose secure user authentication by preventing the exposure if IMSI via transfer the encrypted IMSI from the HLR(Home Location Register) and making the only network entities verified from the HLR use the IMSI value, as the modified mechanism based on the original user authentication protocol to solve this authentication problem. Also the proposed mechanism provides fast user authentication without changing the architecture between new VLR and old VLR in the original GSM user authentication protocol as well as user's anonymity by using a temporary ID.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.1
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• pp.9-14
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• 2014

Objective: The aim of this study was to evaluate the efficiency of the intracytoplasmic morphologically selected sperm injection (IMSI) technique compared with conventional ICSI and previous ICSI attempts in oligo-astheno-teratozoospermia (OAT) patients. Methods: The sperms were selected under high magnification ($6,600{\times}$) and used to induce fertilization in previous ICSI patients by IMSI. These results were compared with previous conventional ICSI cycles in patients with OAT infertility. Results: These results demonstrated no significant difference in the fertilization rate between IMSI and previous ICSI cycles (67.7% vs. 65.0%). However, the pregnancy and implantation rates with IMSI were significantly higher than those of the ICSI cycles (33.3% vs. 12.5% and 14.6% vs. 5.4%, respectively; p<0.05). The miscarriage rate among pregnant patients (18.2% vs. 37.5%) showed no statistically significant difference between groups. Conclusion: Compared to conventional ICSI, this study found that IMSI increased the IVF-ET success rates in patients with OAT.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.10
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• pp.361-372
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• 2016

Identity Privacy issues such as exposures of IMSIs(International Mobile Subscriber Identities) in access network have been consistently raised throughout GSM, UMTS, LTE in 3GPP. The 3GPP specification uses temporary identities instead of IMSI to ensure anonymity of the user. Even if temporary identities are disclosed, Identity Privacy may be maintained at a safe level by security policies such as no linkability and periodic update. But in case of IMSI, it cannot be changed even though it is exposed. There still exist some situations that IMSI is used in clear text for the authentication. Therefore, a protective mechanism for the identity confidentiality is needed. In this paper we propose a protocol based on IBE(Identity-based Encryption) to protect permanent identities in access network. By simplifying the scheme, this protocol has minimized the system impact on current 3GPP environment. And this scheme can be applied to all kind of permanent identities and 3GPP AKA(Authentication and Key Agreement) protocols in access network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.75-81
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• 2011

The UMTS is the most widely used specifications to deploy a mobile system and it supports an automatic roaming function. Users in the UMTS can use their phone numbers even in foreign countries without having to change their mobile phones. Also some users want to use other phone numbers which are allocated in foreign countries. To meet such requirements, many methods have been proposed. However, those require much cost to adopt or are not easy to use. In this paper, we propose a software framework that provides multiple MSISDNs with a single IMSI. The roaming SCP is adopted to modify the procedure of the location update and the mobile-terminated call. In the performance evaluation, we compared the proposed scheme with the standard scheme and the schemes in the related works. The results showed that the proposed scheme has 7.6% lower signaling cost than the mobile-station-based scheme and 9.7% lower cost than the telecommunication-network-based scheme.

• Clinical and Experimental Reproductive Medicine
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• v.41 no.3
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• pp.137-139
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• 2014

The effect of artificial oocyte activation (AOA) with a calcium ionophore on intracytoplasmic morphologically selected sperm injection (IMSI) was examined in patients with histories of repeated failed implantation attempts. Four singleton pregnancies and one twin pregnancy were obtained after embryos transfer (5/14, 35.7%). Therefore, AOA combined with IMSI can be considered an option for cycles with a fertilization defect and recurrent implantation failures.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.759-762
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• 2012

This paper is for EPC(Evolved Packet Core) network to share the load balance by IMSI(International Mobile Subscriber Identity) prefix in MME(Mobility Management Entity). For the telecommunication, it needs to choose the anchoring gateway to use the specific gateway to avoid the traffic load to support the efficient telecommunication service. We propose the way to choose the effective gateway to avoid the traffic load in order for good qualify service. We compare the load between the gateways which are the general gateway and the specific gateway used by proposed concept.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.3
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• pp.81-90
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• 2007

In the UMTS (Universal Mobile Telecommunication System), which is one of 3G mobile communication standards, the protocol called UMTS AKA (Authentication and Key Agreement) is used to authenticate mobile stations. However, the UMTS AKA protocol has some weakness, including network bandwidth consumption between a SN (Serving Network) and a HN (Home Network) and SQN (SeQuence Number) synchronization. In this paper, we propose a new improved protocol for UMTS that overcomes UMTS AKA weakness. Our protocol solves the privacy problem caused by IMSI (International Mobile Subscriber Identity)'s disclosure and provides perfect forward secrecy using ECDH (Elliptic Curve Diffie Hellman).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.157-161
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• 2006

GSM(Global System for Mobile communications) that is the most popular standard for mobile phones, has more than 70% users in the world and the number of users increase continuously. However GSM system has the problem that cannot normally authenticate a user by the exposure of IMSI that is able to uniquely authenticate MS? during the user authentication procedure. In this paper? we provide security enhancement and user privacy by adopting a temporary id and an encryption scheme. Moreover we provide fast user authentication via architecture modification of the conventional GSM user authentication protocol.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.257-260
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• 1998

In this paper, we describe an IMT-2000 system architecture, a protocol stack, and basic MAP scenarios(e.g., registration, call delivery) based on the IS-41 and IS-41 and IS-751. This paper focuses on the MAP scenarios to support the IMSI which is defined for the global roaming between GSM and IS-41 Networks through the Family of System approach. This paper also deals with the design of the MAP protocol stack transported over the ATM networks and introduces the software structure of MAP in IMT-2000 MSC.