• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.4
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• pp.375-382
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• 2015

The dome and neck part of a vessel is generally formed by a hot spinning process with a seamless tube. However, as studies on and design data from the hot spinning process are insufficient, this process has been performed based on trial and error and the experiences of field engineers. Changes in the inner diameter from the bottom to the top of the neck have occurred mainly because of the characteristics of the hot spinning process due to the high-speed rotation of the rollers. In this study, a theoretical and finite element analysis of the vessel is conducted with different material(Cr-13)-supplemented screw threads for tapping and to reduce shape errors. Based on the results, tne structural safety under the operating conditions is evaluated.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.677-683
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• 2009

In this study, we designed and implemented testbed for localization algorithm by using a area reduction method in outdoor environment. The proposed algorithm used 3 steps of area reduction method, which estimated blind nodes position. Also, we have experimented with using a Zigbee module for 5 fixed reference nodes and 4 blind nodes in sensor field of $60m{\times}23m$. The results show that our algorithm is improved the localization accuracy even at the number of ref. node is fixed and the number of blind node is increased. In future research, we will be adding the function of seamless localization in indoor and NLOS(non-line of sight) environment.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.701-708
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• 2006

Since different kinds of home network technologies coexist, seamless connections between different kinds of network protocols are essential for home computing environments. Several kinds of home network middleware have been developed and OSGi(Open Service Gateway Initiative) was initiated mainly for interoperability support with service distribution between various middleware environments. Framework, OSGi service platform, has weaknesses of passive service bundle management, user management and device management. Therefore, this paper resolves passive management parts which are critical weaknesses of OSGi Specification Version 3 and proposes SBM (Service Bundle Manager) to effiently manage various service bundles. Additionally, we verify practical effects of SBM through experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.512-518
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• 2006

Very large-area multi-projector display systems have wide applications since they provide immersible environments. The brightness of projectors in the system is different due to the design and aging of the bulbs, and optical properties of the projectors. Therefore it is imperative to match the brightness characteristics of projectors in the system. This issue has been addressed by many researchers. The state of the art solution considers characteristic of projector's brightness only. In this paper, we propose a method that takes into account brightness of projector as well as the dynamic range of the input image. We increase the dynamic range of the input image to utilize the maximum possible brightness of a projector while satisfying the spatial smoothness constraint. This achieves a seamless multi-display with dramatic brightness improvement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.544-550
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• 2006

Next-generation wireless/mobile networks are envisioned to have an IP-based infrastructure. One of the research challenges for next-generation all IP-based networks is the design of intelligent mobility management technologies that have a seamless mobility and minimal signaling overhead. Recently, HMIPv6 was proposed by the IETF for efficient mobility management. HMIPv6 reduces the amount of signaling and improves the performance of MIPv6 in terms of handover latency. However the MAP can be a single point of performance bottleneck when there are a lot of local movements. HMIPv6 can cause signaling overhead due to the unnecessary location update of idle mobile nodes. Therefore, in this paper, we propose the dynamic paging Mobile IPv6 that reduces the signaling cost of the unnecessary location updates using IP paging and organizes dynamically optimal MAP area according to user's mobility and traffic. We show performance results that are obtained from the average total location update cost and packet delivery cost.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.89-97
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• 2017

The substation is a critical node in the power network where power is transformed in the power generation, transmission and distribution system. The IEC 61850 is a global standard which proposes efficient substation automation by defining interoperable communication and data modelling techniques. In order to achieve this level of interoperability and automation, the IEC 61850 (Part 6) defines System Configuration description Language (SCL). The SCL is an XML based file format for defining the abstract model of primary and secondary substation equipment, communications systems and also the relationship between them. It enables the interoperable exchange of data during substation engineering by standardizing the description of applications at different stages of the engineering process. To achieve the seamless interoperability, multi-vendor devices are required to adhere completely to the IEC 61850. This paper proposes an efficient algorithm required for verifying the interoperability of multi-vendor devices by checking the adherence of the SCL file to specifications of the standard. Our proposed SCL validation algorithm consists of schema validation and other functionalities including information model validation using UML data model, the Vendor Defined Extension model validation, the User Defined Rule validation and the IED Engineering Table (IET) consistency validation. It also integrates the standard UCAIUG (Utility Communication Architecture International Users Group) Procedure validation for quality assurance testing. Our proposed algorithm is not only flexible and efficient in terms of ensuring interoperable functionality of tested devices, it is also convenient for use by system integrators and test engineers.

• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.177-191
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• 2007

Supplier relationship management (SRM) is an important contributor to a company's efficiency and credibility. Although several ways are used to provide SRM functionality, these are often not easily integrated with existing procurement systems. We designed and implemented a practical SRM system called BestChoice SRM and present its design and architecture. It has the core functionality of SRM with the simple adaptability of BestChoice which is a decision support system for evaluating suppliers with the aid of visualized analysis It allows seamless integration with existing systems and permits flexible strategy changes as market conditions shift. The key to this flexibility is template-based segmentation. Ease of integration was demonstrated through the installation of BestChoice SRM at a major Korean commercial e-procurement agency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2985-2991
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• 2013

Train radio system has been constructed in the second stage of Kyung-bu high speed railway adopting TETRA(Terrestial trunk radio) standard at 851MHz frequency band. The base stations of the train radio system should be located along railway track to ensure seamless communication between train and wayside taking the path loss of train radio propagation into consideration. This paper provides a quantitative analysis of the path loss characteristics based on the measurement results of the train radio propagation along the high speed railway. The free space propagation model and Okumura-Hata model are generally used for base station design, but they predicted 10dB lower or 20dB higher than the measured path loss. Linear regression of the field measured data by applying the log-distance model shows path loss exponent is in the 2.8-3.2 range, which can be used to predict the path loss of the train radio propagation.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.69-77
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• 2013

This research validates the correlation between usability and functional attributes whilst comparing the degree of satisfaction of information framework used in museum mobile apps via usability evaluation in pre-visit setting. In cases of Bilbao Guggenheim and American Natural History Museum apps, the degree of satisfaction measured for information service, functional attributes, motivation for actual museum visit and during-visit usability of the apps were all highly evaluated. Such evaluation data indicates the increased usability of apps when mobile applications take user-friendly design that intuitively reflect users' interests and needs. After thorough analysis of correlation between usability and fictional attributes, data pointed to more meaning relationships existed in non-intrusiveness and personalization than other functional attributes. In conclusion, we were able to acknowledge the usability of museum mobile apps depends upon the interaction between content and functional attributes rather than entertainment factor and technology.

• Journal of Digital Contents Society
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• v.16 no.6
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• pp.871-882
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• 2015

AIS-ASM is one of the studies to provide a variety of maritime safety information as well as the information on a ship's position that is their own function, and AIS-ASM has been implemented with adjustment of the relevant regulations since 2004. However, it was reported that the increased use of ASM message on the existing AIS channel affects the part of the existing AIS own function such as the transmission of the ship's position and safe-related information. Also, seamless MSP service is difficult to provide at a low transmission rate of the existing AIS channel. This study aims to reduce the marine officer's workload through automating captain's mandatory reporting items using the one of the next maritime digital communication technology (ASM2.0). For this purpose, we designed and realized the ASM2.0 protocol through analyzing domestic regulations about passenger flight and AIS-ASM message.