• Journal of KIISE:Information Networking
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• v.37 no.2
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• pp.122-134
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• 2010

With the rapidly increasing demand of traffic applications, the need to support seamless and robust multimedia services in the Vehicular Ad hoc Network is growing. Fast handover for the MIPv6 (FMIPv6) developed to solve the MIPv6's problem as well as Mobile IPv6 (MIPv6) for basic mobility protocol have been developed to support seamless handover in mobile environment. However, MIPv6 and FMIPv6 are useless for Quality-of-Service (QoS) services such as multimedia applications due to the long handover latency and the packet loss problem. In this paper, we propose a seamless and robust handover scheme that supports multimedia services in Vehicular Ad hoc Network using oCoA and background DAD. Through performance evaluation, we show that the proposed scheme is more proper for Vehicular Ad hoc Network than other schemes.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.1
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• pp.7-14
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• 2014

The rapid increase of mobile devices such as smart phone and smart pad have raised the needs for seamless multimedia services during moving at anytime and anywhere. Current 4G mobile devices are equipped with both 4G (LTE) and WLAN (WiFi) interfaces, and mobile services operators provide wireless Internet services using 4G network with a wider coverage and WiFi zone. Generally users prefer to use the Internet services through WLAN rather than LTE in the coverage of WLAN. However, since WLAN has a long L2 handover latency, it is difficult to support seamless services during a handover. In this paper, we proposed an efficient handover scheme based on flow mobility for WLANs to support a seamless service during handovers by using the overlaid 4G network with a wider coverage. Also, we showed the outperformance of the proposed scheme on a testbed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.54-57
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• 2007

Much researches have studied for seamless mobility service. Those focused on minimizing the delay time due to the handover. In this paper, we suggest seamless mobility service with the network-based preemptive operations. With these operations, if it's found that the MT(Mobile Terminal)'s handover using L2-trigger event, old access network buffers the delivering data. Therefore this can decrease the data drop rates. And also, this can deal with the ping-pong's phenomenon of MT. At the end of MT's movement, these operations can provide seamless mobility service sending buffered data after checking the MT's movement. This mechanism uses MPLS-LSP(MultiProtocol Label Switching-Label Switched Path) in core network for fast process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.909-918
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• 2006

Recently, the qualities of the call and QoS of data service in mobile wireless IP networks inclusive of internet wired networks are very challenging issues. IntServ, DiffServ and MPLS model for supporting QoS in wired networks are representative models which are investigated generally up to now. While, MIPv4(Mobile IPv4) and MIPv6 are proposed to support mobility management for mobile wireless internet networks. But, MIPv4 and MIPv6 based UDP and TCP/IP protocol have many issues to be solved like efficient QoS and frequent handover management. In this paper, we propose a efficient management platform to support seamless data services and end-to-end QoS management in IP-based wireless mobility environments using transport layer protocol, SCTP which support multi-homing and multi-streaming. We used SCTP protocol and IntServ technology for end-to-end communications to support multi-homing and seamless QoS management in the IP-based mobile wireless networks.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.51-62
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• 2006

The load of this kind of gores, which is heavier than that of any other precedent, and on enormous seamless virtual world characterize the MMORPG(Massively Multiplayer Online Role-Playing Game) genres. In this seamless environment, gamers can usually accept a set of independent spaces, which is being held by independent game servers, os a single big virtual world. Despite the efforts of some developers, gamers are suffered from huge message traffic which comes from the interaction between client and server and the interaction between fold sowers. In this paper, new gore server architecture using MigAgent is proposed which tries to reduce message traffic. Usually, message traffic reaches the climax when a PC(Player Character) is moving to other field server. MigAgent, designed in this thesis, tries to manage this kind of PCs and to ploy o role of user's agent to prepare for the unexpected situation. Improvement of this system is shown by the analysis of the effect of the size ratio of AOI (Area of Interest) and AC (Adjacent Cell).

• Corrosion Science and Technology
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• v.16 no.6
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• pp.305-316
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• 2017

Austenitic stainless steels have been widely used for various systems of nuclear power plants. Among these stainless steels, small pipes with diameter less than 14 inch have been produced in the form of seamless pipe. Annealing and cooling process during the manufacturing process can affect corrosion properties of seamless stainless steels. Therefore, 12 inch-diameter of as-received 304L stainless steel pipe was annealed and aged in this study. Intergranular corrosion resistance was evaluated by ASTM A262 Practice A, C, and E methods. The degree of sensitization was determined using a DL-EPR test. U-bend method in an autoclave was used to evaluate the SCC resistance in 0.01 M $Na_2S_4O_6$ or 40% NaOH solution at $340^{\circ}C$. As-received specimen showed relatively high degree of sensitization and intergranular corrosion rate. Carbon segregation was also observed near grain boundaries. Annealing treatment could give the dissolution of segregated carbon into the matrix. Aging treatment could induce segregation of carbon and finally form carbides. Microstructural analysis confirmed that high intergranular corrosion rate of the as-received seamless pipe was due to micro-galvanic corrosion between carbon segregation and grains.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.4
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• pp.113-125
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• 2012

This study, as one on the neck design of seamless knitwears, set out to make experimental clothes applying various knitting methods to the hem of round neck, seek the knitting methods of finishing touches on the ending part of round neck to enhance function and aesthetic appreciation through measuring tensile strength and assessing wearing sensation, and provide basic data that would be of practical help to developing the design of seamless knitwears and mass production in the national knit industry. The ending part of neck of the seamless knitwear is not only the last stage in making knitwear but also affects the function and appearance of the clothes. The investigator, thus made six different pieces of experimental clothes according to the finishing methods of knitting on the neck, then measured tensile strength and put them to the test by a group of experts for the assessment of wearing sensation. The results were analyzed based on variance analysis(ANOVA), and the items with similar results were put to the Duncan test for intergroup comparison. According to the analysis results of measuring tensile strength, Experimental Clothes B received the highest evaluation, Experimental Clothes E the lowest. Also Experimental Clothes B was ranked the highest in almost every evaluation criteria, whereas Experimental Clothes E was ranked the lowest in the assessment of wearing sensation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.217-219
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• 2018

The method on reconfiguring job priority in service queue has been developed to provide seamless service and to enhance operability of Data Service Platform(DSP) in Korean e-Navigation project that performed by Ministry of Oceans and Fisheries(MOF) since 2016. It plays a critical role for providing seamless services of DSP to expect which services ships request to DSP and how much time it costs to make services for responding them to ships in advance. Therefore, as developing a method on reconfiguring jobs in service queue of DSP with a noble algorithm to analyse priority index in parallel, DSP can provide seamless services to ships regardless of data volume and the number of requests that stacked in service queue.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.117-124
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• 2009

Recently, the application of network technology extends to all areas because of development of digital information technology. Thus, networks are being evolved towards a next-generation communication environments where all information devices, home appliances, and object are connected and interoperated. In order to provide adequate convergence services in IMS-based networks that are the core technology of the next-generation communication environments, seamless service should be possible although the underlying network and the device in use may change in the networks. In this paper, we propose an efficient architecture, algorithm, and protocol of service session control for seamless service in such networks.

• The KIPS Transactions:PartC
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• v.19C no.1
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• pp.71-82
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• 2012

In Next Generation Wireless Networks (NGWN), lots of information, such as voice and video data, will be used in All-IP networks. It is important note that seamless service for users and handoff between heterogeneous networks must be taken into account in such environments. Therefore, in this paper, we propose a SePH(Seamless Proxy based Handoff) using PMIPv6-based proxy model which is enable to improve the performance of handoff in NGWN. The SePH can efficiently support seamless and IP-based mobility by reducing the search process. The performance results show that our proposed scheme outperforms in terms of QoS (Quality of Service) such as throughput, handoff latency, packet loss, and signaling overhead comparing to the existing schemes.