• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.229-239
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• 2014

Smartwork technology, using teleworking, smartwork centers and mobile terminal, provides a flexible work environments without constraints of time and space. Smartwork system to increase the work efficiency has the information protection threats according to their convenience. Thus, in order to build smartwork, it is proper to provide information protection audit to help ensure the information protection. In this paper, we have proposed an infortaion protection audit model at the practical and technical level for building a smartwork environment. We were classified as a terminal, network and server area for information protection, and derived a professional information protection check items. Further, by establishing a smartwork information protection audit time to map ISMS control items, we have proposed an audit model so that it is possible to improve the security and efficiency. It also verified whether the proposed model is suitable or not by doing a survey if deduced audit domain and check items correspond with the purpose of the smartwork information protection audit to auditors and IT specialists. As the result, this study was 97% satisfaction out of 13 check items.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.3
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• pp.131-140
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• 2007

A general medical information service in hospitals recently has been rapidly developed in the effective patient management due to the digitalization. In addition, the hospitals make an effort to support the medical information service in ubiquitous environment. A key requirement in ubiquitous environment is the ability to communicate between the image viewer system using the DICOM standard and a server system to support the medical information service. This paper describes a remote networking system based on the mobile terminal with RFID technology for the medical information service. In order to apply the overall configuration, we first implemented the DICOM viewer system, configured the database to store the patient information, and realized the server/client networking system in mobile terminal environment. In particular, this paper showed the capability for the medical image-based communication as well as the text-based communication.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.372-377
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• 2009

This paper evaluates the performance of three methods for predicting resources requested by mobile's calls and a call admission algorithm based on these predicting methods respectively in wireless networks. The first method is based on Wiener prediction model and the second method is based on the MMOSPRED algorithm and the third method is based on the neural network. The proposed call admission algorithm is based on prioritized handoff call in resource allocation. The resources for future handoff calls are therefore predicted and reserved in advance, and then new calls are admitted as long as the remaining resources are sufficient. We compare their performances in terms of prediction error, new call blocking and handoff dropping probabilities by simulation. Results show that the CAC based on Wiener prediction model performs favorably due to exact resources prediction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.131-140
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• 2011

Proxy Mobile IPv6 (PMIPv6) is designed to provide a network-based localized mobility management protocol, but it does not handle the global mobility of hosts. In this paper, we propose a location management scheme based on Domain Name System (DNS) for PMIPv6. In this proposed scheme, DNS as a location manager provides PMIPv6 for global mobility. In addition, a paging extension scheme is introduced to PMIPv6 in order to support large numbers of mobile terminals and enhance network scalability. To evaluate the proposed location management scheme, we establish an analytical model, formulate the location update and the paging cost, and analyse the influence of the different factors on the total signalling cost. The performance results show how the total signal cost changes under various parameters.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.145-157
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• 2017

Currently, the height of ships that can pass under Busan Harbor Bridge is limited to 60m or shorter, so that large-sized ships of 60m or taller cannot use Busan Harbor international passenger terminal. Accordingly, this study has developed a service which measures continuously the change of bridge height by water level changes and provides such in real-time for safe bridge passage of large-sized ships of 60m or taller. The measurement system comprised of high-precision laser distance measurement device, GPS sensor, optical module, and damping structure is used to measure the bridge height change according to tide level changes, and the measured information is provided in real-time through cloud-based mobile app. Also, in order to secure objective bridge height data for changes to height limits and navigation supports, the observation data was analyzed and forecast model was drawn. As a result, it became an objective evidence to revise the passage height rules of the Busan Port Bridge from 60 meters to 63 meters.