• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.21-28
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• 2007

Along with the development of telecommunication technology, educational role has been considerably changed and NEIS is introduced and operated for the digital educational administration. However, the function of NEIS is so limited when operated in each school. As a result, Korean government prepares the plan to install and operate a new School Affairs System by separating 3 areas from 27 areas of NEIS. School Affairs System has been used in schools since March, 2006. In this regard, this study attempts to analyze the current status and tasks of using the system in elementary schools. The result of the study shows that about 67% teachers use the system once or twice a day. Most of teachers answer that they get help from other teachers if they have any problem in operating the system. Many teachers affirmatively answer to the design and function of the system, and they are satisfied with the convenience and efficiency of the system. However, they feel difficulty to be familiar with the system sue to the frequent change. The importance of electronic certificate and personal information is well recognized and managed in terms of the security of the system. Facilities need to be well equipped, and information exchange system need to be developed to accept each school's request to improve the function of the system. In addition, applicable laws need to be arranged, clear guideline of educational administration agency and principal's strong intention are required to relieve teachers' work load.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.607-616
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• 2008

By the advancement of computer & network technology, the paridigm of 'Network Computer' has been realizing`. In what is called network computer, computer system and computing resource is incomparably seem to be expanded compared with conventional network technology[1]. Network connected computer system consitute a massive virtual computer, it is possible for people to use an enourmous amout of computing resource distributed widely through the network. It is also possible that we make client lightweight by the use of computer system & all shared computing resources on the network in our computer processing and we call this type of client system as thin-client. Thin-client and network computer are on and the same network paradigm in that both paradigm featuring the active use of computer system and resource on the network[2]. In network computer paragem, network itself is regarded as a basic platform for the transfer of application, so it is possible that client access remote serve system to run remote applications through the network[3]. In this paper, we propose the system architecture for the implementation of network computer by the use of Web browser, X window system and Pyjamas. By the use of network computer proposed in this paper, it is possible for people to run application on the server system as if he run local application, and it is expected to improve the security and maintenance efficiency.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.415-426
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• 2005

Wireless internet, which becomes a hot social issue, has limitations due to the following characteristics, as different from wired internet. It has low bandwidth, frequent disconnection, low computing power, and small screen in user terminal. Also, it has technical issues to Improve in terms of user mobility, network protocol, security, and etc. Wireless internet server should be scalable to handle a large scale traffic due to rapidly growing users. In this paper, wireless internet proxy server clusters are used for the wireless Internet because their caching, distillation, and clustering functions are helpful to overcome the above limitations and needs. TranSend was proposed as a clustering based wireless internet proxy server but it has disadvantages; 1) its scalability is difficult to achieve because there is no systematic way to do it and 2) its structure is complex because of the inefficient communication structure among modules. In our former research, we proposed the All-in-one structure which can be scalable in a systematic way but it also has disadvantages; 1) data sharing among cache servers is not allowed and 2) its communication structure among modules is complex. In this paper, we proposed its improved scheme which has an efficient communication structure among modules and allows data to be shared among cache servers. We performed experiments using 16 PCs and experimental results show 54.86$\%$ and 4.70$\%$ performance improvement of the proposed system compared to TranSend and All-in-one system respectively Due to data sharing amount cache servers, the proposed scheme has an advantage of keeping a fixed size of the total cache memory regardless of cache server numbers. On the contrary, in All-in-one, the total cache memory size increases proportional to the number of cache servers since each cache server should keep all cache data, respectively.

• Archives of design research
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• v.11 no.1
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• pp.291-302
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• 1998

This paper covers the development process of multimedia evaluation system, especially focused on customer satisfactory factors while customers navigating net-based Interactive multimedia system. Customers usually experience new level of interaction cased by newly developed web-based technology In ordinary multimedia system. However, if it gives customers satisfactory experience is a matter of question. To find out the relationship between customer satisfaction and interactivity factors exposed by multimedia system, a model has been developed which describes the structure of web-based multimedia system and its relation to customer satisfactory factors. Five different experiments, including 'semantic differential', 'focus group interview', and 'expert review', has been conducted and four customer satisfactory factors were identified. Those are 'customery value', 'structural perfectness', 'visual perfectness', and 'contemporaneity'. With these factors and newly delveoped evaluation system, 7 different web-site has been evaluated and analyzed at the end of this report.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.91-102
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• 2011

Smart work is deeply embedded in our contemporary lives. This is called Smart Life. The expansion of communication, caused by smart life is utilized for the political purposes of politicians, political candidates, and political policies. Chiefly, smart life includes improvement in awareness, personal relations, and policy advocacy. Socially, smart life leads the proliferation of issues and civil movement. In particular, smart life has a significant effect on culture. In the case of K-POP, it is disseminated going beyond space time. It enhances economic value added by joining and sharing at the same time. Smart life has numerous advantages such as improving the quality of life, but it might cause inconvenience depending on users because there are differences in acceptance according to generations. Due to the heavy weight on the device, there are some side-effects such as lacking in human thinking, disclosure in private life, lacking in basic securities, increase in information addicts who are anxious when they do not get on the Internet or SNS, and interference with work. However, this inconvenience can change into convenience when users are accustomed to it. Like this, smart life influences politics, economy, society, and culture a lot. Working environment of smart life is a new paradigm, which can generate high performance through working in an exciting and bright atmosphere with easy economy and putting value on results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.255-258
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• 2011

Wi-Fi is a rapidly spreading communications network with Smart phone's publication, the technology has become Ubiquitous-based core network which is connected to personal computers, laptops, and tablet PC. Wi-Fi can send currently a variety of data standard due to developed wireless LAN communications network. One of Wi-Fi standard protocols, which is IEEE 802.11n, use 2.4GHz and 5GHz band. 2.4GHz band is used for 802.11b/g protocol because wavelength is long, diffraction and receiving distance is enough to connect other device. 5GHz band has more available channels to use than 2.4GHz band, so there is no frequency interference of other wireless device such as Bluetooth, RFID. Moreover, there is low interference between channels due to small users in each bandwidth level. In the thesis, we are going to analyze 802.11a/b/g protocol which has used since the beginning of Wi-Fi protocol and 802.11n protocol which is used lately. Furthermore, we look into development and direction for standardization of the next generation wireless LANs which are 802.11ac and 802.11ad. In addition, we will consider for the security, vulnerabilities and its countermeasure in Wireless LAN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.730-737
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• 2003

In this paper, we present an efficient authentication proxy for IEEE 802.1x systems based on the port-based access control mechanism. An IEEE 802.1x system consists of PC supplicants, a bridge with authentication client functions, and an authentication server. For the network security and user authentication purposes, a supplicant who wants to access Internet should be authorized to access the bridge port using the Extended Authentication Protocol (EAP) over LAN. The frame of EAP over LAN is then relayed to the authentication server by the bridge. After several transactions between the supplicant and the server via the bridge, the supplicant may be either authorized or not. Noting that the transactions between the relaying bridge and the server will be increased as the number of supplicants grows in public networks, we propose a scheme for reducing the transactions by employing an authentication proxy function at the bridge. The proxy is allowed to cache the supplicant's user ID and password during his first transaction with the server. For the next authentication procedure of the same supplicant, the proxy function of the bridge handles the authentication transactions using its cache on behalf of the authentication server. Since the main authentication server handles only the first authentication transaction of each supplicant, the processing load of the server can be reduced. Also, the authentication transaction delay experienced by a supplicant can be decreased compared with the conventional 802.1x system.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.165-182
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• 2009

Mobile IPv6 spends considerable bandwidth considering that its signal volume is proportional to the mobile and also it should be strengthened to support the binding signal volume, the traffic, and effective mobility. So, the study in NEMO(Network Mobility), an extended version of Mobile IPv6, has been conducted. NEMO provides its mobility by putting several mobiles and more than one portable router into one unit called as mobile network. Because nodes access Internet via the portable router at this time, it receives transparency without any additional work and that much reduces binding signal while solving binding storm. By supporting mobility, NEMO is able to have various mobile structures which realize several networks hierarchically and it is necessary to improve its safety and security by authenticating among the upper networks or the lower ones while moving. Also, it is extremely required to begin a study in the device to improve efficiency accompanied with mobility, which is executed by the fast hand-off as well as the safe authentication. For those reasons, this paper not only classifies various NEMO mobile scenarios into 7 ways, but also provides AAA authentication of each scenario, the authentication through the safety authentication and fast handoff authentication using F+HMIPv6 and the way to reduce both signaling volume and packet delays efficiently during the handoff.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.585-600
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• 2012

Security issues in online games are increasing as the online game industry grows. Real money trading (RMT) by online game users has become a security issue in several countries including Korea because RMT is related to criminal activities such as money laundering or tax evasion. RMT-related activities are done by professional work forces, namely gold-farmers, and many of them employ the automated program, bot, to gain cyber asset in a quick and efficient way. Online game companies try to prevent the activities of gold-farmers using game bots detection algorithm and block their accounts or IP addresses. However, game bot detection algorithm can detect a part of gold-farmer's network and IP address blocking also can be detoured easily by using the virtual private server or IP spoofing. In this paper, we propose a method to detect gold-farmer groups by analyzing their connection patterns to the online game servers, particularly information on their routing and source locations. We verified that the proposed method can reveal gold-farmers' group effectively by analyzing real data from the famous MMORPG.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.153-166
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• 2011

Recent trends in mobile device market whose services are rapidly expanding to provide wireless internet access are drawing people's attention to mobile security. Especially, since threats to information leakage are reaching to the critical level due to the frequent interchange of important data such as personal and financial information through wireless internet, various encryption algorithms has been developed to protect them. The encryption algorithms confront the serious threats by the appearance of side channel attack (SCA) which uses the physical leakage information such as timing, and power consumption, though the their robustness to threats is theoretically verified. Against the threats of SCA, researches including the performance and development direction of SCA should precede. Among tile SCA methods, the power analysis (PA) attack overcome this misalignment problem. The conventional methods require large computational power and they do not effectively deal with the delay changes in a power trace. To overcome the limitation of the conventional methods, we proposed a novel alignment method using peak matching. By computer simulations, we show the advantages of the proposed method compared to the conventional alignment methods.