• Journal of the Korea Convergence Society
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• v.3 no.3
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• pp.7-12
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• 2012

mVoIP (mobile Voice over Internet Protocol) service is a technology to transmit voice data through an IP network using mobile device. mVoIP provides various supplementary services with low communication cost. It can maximize the availability and efficiency by using IP-based network resources. In addition, the users can use voice call service at any time and in any place, as long as they can access the Internet on mobile device easily. However, SIP on mobile device is exposed to IP-based attacks and threats. Observed cyber threats to SIP services include wiretapping, denial of service, and service misuse, VoIP spam which are also applicable to existing IP-based networks. These attacks are also applicable to SIP and continuously cause problems. In this study, we analysis the threat and vulnerability on mVoIP service and propose several possible attack scenarios on existing mobile VoIP devices. Based on a proposed analysis and vulnerability test mechanism, we can construct more enhanced SIP security mechanism and stable mobile VoIP service framework after eliminating its vulnerability on mobile telephony system.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.143-151
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• 2008

Execute IP traceback at this paper as target an intruder's attacking that Bypass Attack in order to avoid an exposure of own Real IP address Design IP traceback server and agent module, and install in Internet network system for Real IP traceback. Set up detection and chase range aggressive loop around connection arbitrariness, and attack in practice, and generate Real IP data cut off by fatal attacks after data and intrusion detection accessed general IP, and store to DB. Generate the Forensic data which Real IP confirms substance by Whois service, and ensured integrity and the reliability that buy to early legal proof data, and was devoted to of an invader Present the cyber criminal preventive effect that is dysfunction of Ubiquitous Information Society and an effective Real IP traceback system, and ensure a Forensic data generation basis regarding a judge's robe penalty through this paper study.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2109-2112
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• 2003

Diameter-MIPV4 프로토콜은 기존 Mobile IP(MIP)의 취약한 키 분배 문제를 해결하고 이동노드에 대해 인증 및 권한 검증, 과금 서비스 등을 지원함으로써 보다 개선된 보안 메커니즘을 제안하고 있다. 그러나 흠 망의 Diameter 서버에 의해 인증 및 등록이 수행된 후 공중망을 통해서 이동노드에게 세션키를 분배하는 것은 많은 보안상 공격에 노출될 수 있으며 원격지 도메인간의 빈번한 등록 메시지 교환은 통신 지연을 야기 시킬 수 있다. 본 논문에서는 안전한 세션키 분배를 위해서, 이동 노드의 등록 수행 과정 중 홈 망과 방문 망 사이에 IPsec(IP security) 터널을 구축함으로써 공중망에서의 세션키 유출 위협을 감소시켰다. 또한 네트워크의 계층성과 Micro-Mobility MIP 메커니즘을 이용하여 동일 도메인 내에서의 핸드오프 시 이동 노드의 인증 및 등록, 세션키 분배를 지역화 함으로써 통신 지연 문제를 효율적으로 개선하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.91-98
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• 2021

In most hacking attacks, hackers tend to access target systems in a variety of circumvent connection methods to hide their original IP. Therefore, finding the attacker's IP(Internet Protocol) from the defender's point of view is one of important issue to recognize hackers. If an attacker uses a proxy, original IP can be obtained through a program other than web browser in attacker's computer. Unfortunately, this method has no effect on the connection through VPN(Virtual Private Network), because VPN affects all applications. In an academic domain, various IP traceback methods using network equipments such as routers have been studied, but it is very difficult to be realized due to various problems including standardization and privacy. To overcome this limitation, this paper proposes a practical way to use client's network configuration temporarily until it can detect original IP. The proposed method does not only restrict usage of network, but also does not violate any privacy. We implemented and verified the proposed method in real internet with various VPN tools.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.273-279
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• 2013

The purpose of the study was to present basic data to evaluation of the spatial resolution for exposure class(EC) in computed radiography(CR) by using the modulation transfer function(MTF). In this study, MTF was measured the edge method by using image plate(IP) of $100{\mu}mm$ pixels. A standard beam quality RQA5 based on an international electro-technical commission(IEC) standard was used to perform the X-ray imaging studies. Digital imaging began to set the sensitivity to EC 50, 100, 200, 300, 400, 600, 800, 1200 in X-ray irradiated to IP. The MTF 50% and 10% in the final images was analysis by using an authorized image analysis program the Origin 8.0 and the image J. As a results, the EC 200 was the best spatial resolution at MTF 50% ($1.979{\pm}0.114lp/mm$) and MTF 10% ($3.932{\pm}0.041$). Therefore, the EC 200 could be useful for the diagnosis of diseases that require high spatial resolution such as fractures.

• The KIPS Transactions:PartA
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• v.14A no.1 s.105
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• pp.1-14
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• 2007

MPICH-G2 is an MPI implementation to solve complex computational problems by utilizing geographically dispersed computing resources in grid environments. However, the computation nodes in MPICH-G2 are exposed to the external network due to the lack of supporting the private IP clusters, which raises the possibility of malicious security attacks. In order to address this problem, we propose MPICH-GP with a new relay scheme combining NAT(Network Address Translation) service and an user-level proxy. The proxy running on the front-end system of private IP clusters forwards the incoming connection requests to the systems inside the clusters. The outgoing connection requests out of the cluster are forwarded through the NAT service on the front-end system. Through the connection path between the pair of processes, the requested MPI jobs can be successfully executed in grid environments with various clusters including private IP clusters. By simulations, we show that the performance of MPICH-GP reaches over 80% of the performance of MPICH-G2, and over 95% in ease of using RANK management method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.281-284
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• 2011

Smart phone is being used in the job as the ubiquitous society will Without being restricted by the time and place and devices. The rapid increase in the use of smart phones has brought the activation of the mobile job. And government agencies have brought in the transition to a smart society. In this paper, using a Voice over Internet protocol(VoIP) service for your smart phones to enhance security is the study of encryption technologies. External and internal signals, and call encryption and security standards of administrative agencies is the study of VoIP. Smart phone VoIP service is a study that security of equipment certificate, the internal signal and call encryption. This paper will contribute what using smart phone VoIP security and usability In smart generation.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.573-579
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• 2019

The purpose of this study is predicted easily the entrance surface dose (ESD) in chest digital radiography. We used two detector type such as flat-panel detector (FP) and IP (Imaging plate detector). ESD was measured at each exposure condition combined tube voltage with tube current using dosimeter, after attaching on human phantom, it was repeated 3 times. Phantom images were evaluated independently by three chest radiologists after blinding image. Dose-area product (DAP) or exposure index (EI) was checked by Digital Imaging and Communications in Medicine (DICOM) header on phantom images. Statistical analysis was performed by the linear regression using SPSS ver. 19.0. ESD was significant difference between FP and IP($85.7{\mu}Gy$ vs. $124.6{\mu}Gy$, p=0.017). ESD was positively correlated with image quality in FP as well as IP. In FP, adjusted R square was 0.978 (97.8%) and linear regression model was $ESD=0.407+68.810{\times}DAP$. DAP was 4.781 by calculating the $DAP=0.021+0.014{\times}340{\mu}Gy$. In IP, adjusted R square was 0.645 (64.5%) and linear regression model was $ESD=-63.339+0.188{\times}EI$. EI was 1748.97 by calculating the $EI=565.431+3.481{\times}340{\mu}Gy$. In chest digital radiography, the ESD can be easily predicted by the DICOM header information.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.239-241
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• 2006

This research implemented VoIP phone for Advertisement service that used display(LCD) of internet telephone. If it is advertised using this advertisement service model, We don't make payment printing cost and delivering cost for advertisement. And the advertisement using VoIP phone can deliver to customers in real-time that high grade advertising exposure. The customer can use information about opening and closing store in real-time. Hence, in this paper we suggest more efficient advertisement technique using VoIP phone for Advertisement service.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.37-48
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• 2008

VoIP service is a transmission of voice data using SIP protocol on IP based network, The SIP protocol has many advantages such as providing IP based voice communication and multimedia service with cheap communication cost and so on. Therefore the SIP protocol spread out very quickly. But, SIP protocol exposes new forms of vulnerabilities on malicious attacks such as Message Flooding attack and protocol parsing attack. And it also suffers threats from many existing vulnerabilities like on IP based protocol. In this paper, we propose a new Virtual Proxy Server system in front of the existed Proxy Server for anomaly detection of SIP attack and stateful management of SIP session with enhanced security. Based on stateful virtual proxy server, out solution shows promising SIP Message Flooding attack verification and detection performance with minimized latency on SIP packet transmission.