• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.883-891
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• 2008

In 2006, Lee and Ahn proposed a matrix-based RFID authentication protocol which eliminates the security problems in HB and $HB^+$ RFID authentication protocols. Their proposed protocol provides the following three merits: (1) it reduces the computational costs of the RFID tag. (2) it reduces the communication overhead between the reader and the tag. (3) it protects the user privacy. However, this paper points out that Lee and Ahn's proposed protocol is insecure to various attacks because it does not provide mutual authentication which the RFID tag does not authenticate the legality of the RFID reader unlike their claims. In addition, this paper proposes an improved matrix-based RFID mutual authentication protocol that can provide the mutual authentication. As a result, the proposed protocol not only can provide strong security and but also guarantee high efficiency because it reduces the communication rounds compare with Lee-Ahn's protocol.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.874-882
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• 2008

To test the current collection characteristics between overhead contact lines and pantograph in a real speed scale costs too much, therefore, it is very difficult to be realized especially in a high speed region. As a alternative, the speed scale-downed tests is proposed. In this paper, the experimental methodology and effectiveness of the speed scale-downed tests are discussed through the dynamic simulation evaluations. To get a more precise test results to the real speed scale test in the 1/2 and 1/4 speed scale-downed tests, various experimental conditions are discussed. Throughout the simulation in a various conditions the effectiveness are evaluated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.107-119
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• 2013

This paper reinforced security under the network evaluation of wire wireless integration of NEMO (NEwork MObility) supporting mobility and network-based PMIPv6 (Proxy Mobile IPv6). It also proposes $SK-L^2AS$ (Symmetric Key-Based Local-Lighted Authentication Scheme) based on simple key which reduces code calculation and authentication delay costs. Moreover, fast handover technique was also adopted to reduce handover delay time in PMIPv6 and X-FPMIPv6 (eXtension of Fast Handover for PMIPv6) was used to support global mobility. In addition, AX-FPMIPv6 (Authentication eXtension of Fast Handover for PMIPv6) is proposed which integrated $SK-L^2AS$ and X-FPMIPv6 by applying Piggybacks method to reduce the overhead of authentication and signaling. The AX-FPMIPv6 technique suggested in this paper shows that this technique is better than the existing schemes in authentication and handover delay according to the performance analysis.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.108-113
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• 2004

Marinas are often located in prime port side locations. hi Korea these locations are already developed and reclamation of the existing properties poses many difficulties and financial overhead. Also, to develop a standard marina in Korea with tide ranges up to 6 meters would require considerable dredging and reclamation works needing long lead times and large SOC costs. The Ocean Space's floating marina system is an independent offshore floating static level system that does not require fixed location breakwaters. The entire marina floats with the tide giving a calm consistent berthing condition for vessels irrespective of the surrounding tide and weather conditions. The floating marina system provides also for all of functions needed to marina comprising a breakwater to protect the vessels, the pontoon system to house the vessels, a dub house and retail tourism precinct, fuel reservoir and associated support facilities in a turn key self contained unit. The modular nature of the system will mean that initial demand can be met with simple units and then further modules can be added quite easily without the related expansion difficulties or infrastructure. This paper contains the main characteristics of the floating marina system and tire design process of the structure. The mooring, motion & stability analysis, the overall & local structural design and the mooring & anchor system design are introduced in this paper.

• Convergence Security Journal
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• v.15 no.5
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• pp.3-8
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• 2015

Most mobile cloud computing system use public key cryptography to provide data security and mutual authentication. A variant of traditional public key technologies called Identity-Based Cryptography(IBC) has recently received considerable attention. The certificate-free approach of IBC may well match the dynamic qualities of cloud environment. But, there is a need for a lightweight secure framework that provides security with minimum processing overhead on mobile devices. In this paper, we propose to use hierarchical ID-Based Encryption in mobile cloud computing. It is suitable for a mobile network since it can reduce the workload of root Public Key Generators by delegating the privilege of user authentication and private key generation. The Identity-Based Encryption and Identity-Based Signature are also proposed and an ID-Based Authentication scheme is presented to secure data processing. The proposed scheme is designed by one-way hash functions and XOR operations, thus has low computation costs for mobile users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.337-349
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• 2013

In this paper, we propose a new mobility management scheme, called i-FP(intelligent Fast PMIPv6). Our proposed i-FP scheme is addressed for solving the existing local mobility management problems from legacy frameworks. To move MN(Mobile Node) to other networks in one domain, i-FP employs three network entities which are extended from PMIPv6(Proxy Mobile IPv6), LMA(Local Mobility Anchor), MAG(Mobile Access Gateway) and MN. In i-FP, the three network entities can reduce the handover delay time of MNs. Also, i-FP uses an IP header swapping mechanism to avoid the traffic overhead and improve the throughput of network. To evaluate the performance of i-FP, we analyze our i-FP, HMIPv6(Hierarchical Mobile IPv6) and PMIPv6 which are legacy protocols of local mobility management in terms of various parameters. Finally, our i-FP scheme shows good performance(reduction of routing hops 10.2%, signaling costs 58.5% and handover delay 16.3%) than other network schemes for the total cost.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.193-204
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• 2012

This paper specifies a low-cost global mobility management architecture and protocol procedure called LC-$GM^2$, which is based on Proxy Mobile IPv6. In LC-$GM^2$, mobility management is performed by the network entity. The benefit is the elimination of the wireless link data delivery tunnel overhead between a mobile node and the access router. To compare with the well-known Hierarchical Mobile IPv6 mobility management protocol and GPMIP, the location update, packet delivery, and total cost functions generated by a mobile node during its average domain residence time are formulated for each protocol based on Fluid-flow mobility model. Then, the impacts of various system parameters on the cost functions are analyzed. The analytical results indicate that the proposed global mobility management protocol can guarantee lower total costs.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.958-969
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• 2002

No one doubts that textile and apparel industries have contributed to economic miracles of the export-led growth in Korea. However, by the turning of 1990′s, these sectors have encountered many problems such as decreasing of domestic production and exports mainly due to wage rise and shortage. Therefore, foreign direct investment to the low labor cost countries has been enlarged for a way of improving its competitiveness and increasing exports. However, no intensive study has been made exploring current investments and future directions. This study focuses Vietnam as one of the promising overseas investment countries. The purposes of this study are to analyze current investment status of Korean textiles and apparel firms in Vietnam, to explore merits and problems Vietnam has, and to present useful implications and strategies for Korean textiles and apparel companies. Analysis of current secondary data suggests that Korean apparel industry, rather than textiles industry, have invested more in Vietnam, mostly in southern Ho Chi Minh City. Investments of Korean apparel and textile firms have shown steady increase from 1990 but have turned to a decrease from 1995. Findings suggested that Vietnam has merits for attracting foreign investment since it provides relatively cheap labor and outstanding skillful hands suitable for apparel and textiles industries. In addition, because of EU quota increase and the trade agreement between Vietnam and USA it is likely for firms in Vietnam to increase exports to EU and USA Rapid expansion of domestic apparel market and "Korean trend (Han Rue)" in Vietnam resulted from successful star marketing of Korean firms are another merits Vietnam has to the Korean fm. However, regulations of central government, low efficiency of bureaucratic and stiff administrative process, difficulty of making decision in case of joint venture, lack of social overhead capital, high factory construction costs, weak construction condition, and the excessive competition among investment enterprises have found to be problems. Based on pros and cons of investment to Vietnam, marketing strategies, practical implications and future directions were suggested.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.2827-2848
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• 2021

Mobile Crowdsourcing (MCS) has become an emerging paradigm evolved from crowdsourcing by employing advanced features of mobile devices such as smartphones to perform more complicated, especially spatial tasks. One of the key procedures in MCS is to collect answers from mobile users (workers), which may face several security issues. First, authentication is required to ensure that answers are from authorized workers. In addition, MCS tasks are usually location-dependent, so the collected answers could disclose workers' location privacy, which may discourage workers to participate in the tasks. Finally, the overhead occurred by authentication and privacy protection should be minimized since mobile devices are resource-constrained. Considering all the above concerns, in this paper, we propose a lightweight and privacy-preserving answer collection scheme for MCS. In the proposed scheme, we achieve anonymous authentication based on traceable ring signature, which provides authentication, anonymity, as well as traceability by enabling malicious workers tracing. In order to balance user location privacy and data availability, we propose a new concept named current location privacy, which means the location of the worker cannot be disclosed to anyone until a specified time. Since the leakage of current location will seriously threaten workers' personal safety, causing such as absence or presence disclosure attacks, it is necessary to pay attention to the current location privacy of workers in MCS. We encrypt the collected answers based on timed-release encryption, ensuring the secure transmission and high availability of data, as well as preserving the current location privacy of workers. Finally, we analyze the security and performance of the proposed scheme. The experimental results show that the computation costs of a worker depend on the number of ring signature members, which indicates the flexibility for a worker to choose an appropriate size of the group under considerations of privacy and efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.565-586
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• 2022

Cloud storage's elastic expansibility not only provides flexible services for data owners to store their data remotely, but also reduces storage operation and management costs of their data sharing. The data outsourced remotely in the storage space of cloud service provider also brings data security concerns about data integrity. Data integrity verification has become an important technology for detecting the integrity of remote shared data. However, users without data access rights to verify the data integrity will cause unnecessary overhead to data owner and cloud service provider. Especially malicious users who constantly launch data integrity verification will greatly waste service resources. Since data owner is a consumer purchasing cloud services, he needs to bear both the cost of data storage and that of data verification. This paper proposes a verification control algorithm in data integrity verification for remotely outsourced data. It designs an attribute-based encryption verification control algorithm for multiple verifiers. Moreover, data owner and cloud service provider construct a common access structure together and generate a verification sentinel to verify the authority of verifiers according to the access structure. Finally, since cloud service provider cannot know the access structure and the sentry generation operation, it can only authenticate verifiers with satisfying access policy to verify the data integrity for the corresponding outsourced data. Theoretical analysis and experimental results show that the proposed algorithm achieves fine-grained access control to multiple verifiers for the data integrity verification.