• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.519-526
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• 2016

As marine accidents happen frequently, it is required to establish a marine traffic monitoring system, which is designed to improve the safety and efficiency of navigation in VTS (Vessel Traffic Service). For this aim, recently, X-band marine radar is used for extracting the sea surface information and, it is necessary to retrieve wave information correctly and provide for the safe and efficient movement of vessel traffic within the VTS area. In this paper, three different current estimation algorithms including the classical least-squares (LS) fitting, a modified iterative least-square fitting routine and a normalized scalar product of variable current velocities are compared with buoy data and then, the iterative least-square method is modified to estimate wave information by improving the initial current velocity. Through several simulations with radar signals, it is shown that the proposed method is effective in retrieving the wave information compared to the conventional methods.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.222-228
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• 2010

In this paper, we propose a new approach to noise estimation incorporating spectral deviation with soft decision scheme to enhance the intelligibility of the degraded speech signal in non-stationary noisy environments. Since the conventional noise estimation technique based on soft decision scheme estimates and updates the noise power spectrum using a fixed smoothing parameter which was assumed in stationary noisy environments, it is difficult to obtain the robust estimates of noise power spectrum in non-stationary noisy environments that spectral characteristics of noise signal such as restaurant constantly change. In this paper, once we first classify the stationary noise and non-stationary noise environments based on the analysis of spectral deviation of noise signal, we adaptively estimate and update the noise power spectrum according to the classified noise types. The performances of the proposed algorithm are evaluated by ITU-T P. 862 perceptual evaluation of speech quality (PESQ) under various ambient noise environments and show better performances compared with the conventional method.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.77-85
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• 2007

According to the survey data during the Japanese Occupation Period, the length of South Korea's coastline is about 11,542 km, including the coastlines of land and islands. It will be very expensive and time-consuming to revise/renew accurately this coastline data through site survey, it will cost great money and time. Also, various development projects such as reclamation works on public waters, constructions of ports/harbors, etc. are frequently changing the coastal areas and coastlines, causing many renewal projects on coastal maps. For such reason, appropriate alternatives for site survey are necessary. This paper demonstrate the utilization of RTK-GPS survey data, qualitative analysis and 3D topographic analysis for extracting the change in five coastal areas (Songjeong, Haeundae, Kwanganri, Songdo and Dadaepo). The local experimental areas subjected for this research were limited to five coastal areas near Busan.

• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.543-548
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• 2014

Modern network has a complex structure that includes diverse and heterogeneous equipments to cope with multi-purpose functions. For proper administration of networks with complex structures, NETCONF protocol has been proposed. It still, however, has a few unresolved issues with each layer of the protocol. Tackling one of the less attended issues of NETCONF, this article suggests a technique which can efficiently update the configuration data of network equipments when multiple administrators are present. Specifically, for efficient updates of the network equipment configuration, we propose to add a pre-examination of the data dependent to algorithm in 오퍼레이션 layer and modify the data structure for managing XML documents for changing the configurations of network equipments. We have implemented and experimented with our method and confirmed that our approach brought an significant overall performance improvement to NETCONF.

• Journal of Internet Computing and Services
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• v.3 no.2
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• pp.87-95
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• 2002

Due to rapid development of high speed wire/wireless internet technologies, at the current age, it cares into being one phenomenon that the internet business is able to work on anyplace and anytime. In this environment, a technology of mobile agent provides very useful mechanism for personal handheld devices because of supporting migration as autonomously executable software object Instead of users. Therefore, this paper focuses on Implementing a mobile agent platform for personal handheld devices, which supports mobile agents in wire/wireless internet environment. To do this, we construct the system with modified JAMAS, based on Java, in our previous research. Based on our proposed system, we implement the browsing application in personal handheld devices to access the MIB(Management Information Base) on SNMP(Simple Network Management Protocol), which supervises network environment on wire/wireless internet. This proposed application system is easily to access the MIB managed by SNMP agent. then provides network map viewer and updates the MIB through the browser to network administrator. As a result, we can support application area of mobile agents such as hare network management. M-Commerce, integration of remote database systems, active message and active network with personal handheld devices.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.3
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• pp.191-198
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• 2007

According to the survey data during the Japanese Occupation Period, the length of South Korea's coastline is about 11,542km, including the coastlines of mainland and islands. To accurately revise/renew this coastline data through site survey, it will cost great money and time. Also, various development projects such as reclamation works on public waters, constructions of ports/harbors, etc. This paper used aerial photographs, satellite image data and GPS survey data with certain intervals to monitor the change in coastal areas of Songieong, Haeundae, Kwanganri, Songdo and Dadaepo. The local area subjected for this research was limited to areas near Busan. The specific contents of this research include. Launching qualitative/time series analyses on the change of coastal areas using aerial photographs, satellite image data and RTK-GPS surveys.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.9 no.1
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• pp.221-240
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• 1998

This study concerns information quality of the database which has been produced in the ASKERIC database. The measures used in this study were accuracy of the records. consistency, completeness and currency. Accuracy was measurred in terms of the keywords used in different ways in the US and Britain and the spelling errors in the records. Consistency was measured in terms of 'see also' and 'see reference' mechanism and character capitalization. Completeness was measured as follows： completeness of the search fields in the record and relevance of search fields. Currency was measured using the publication date. The experimental result showed that ERIC databases had some errors in terms of accuracy. consistency. completeness and currency. However, continuous striving for the automatic error checking functions and the policy of feedback from users have contributed to the improvement of the quality in ERIC databases.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.193-202
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• 2021

The update of a high-precision map was carried out by modifying the geometric information using ortho-images or point-cloud data as the source data and then reconstructing the relationship between the spatial objects. These series of processes take considerable time to process the geometric information, making it difficult to apply real-time route planning to a vehicle quickly. Therefore, this study proposed a method to update the road network for route planning using a graph data structure and storage type of graph data structure considering the characteristics of the road network. The proposed method was also reviewed to assess the feasibility of real-time route information transmission by applying it to actual road data.

• Journal of the Korea Society for Simulation
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• v.17 no.2
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• pp.21-29
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• 2008

The High Level Architecture(HLA) specifies a framework for interoperation between heterogeneous simulators, and Run-Time Infrastructure(RTI) is a implementation of the HLA Interface Specification. The Data Distribution Management(DDM) services, one category of IEEE 1516 HLA/RTI management services, control filters for data transmission and reception of data volume among simulators. In this paper, we propose design concept of DDM and show its implementation for light-weighted RTI. The design concept of DDM is to minimize total amount of message that each federate and a federation process generate using the rate of RTI service execution. The design of our proposed DDM follows that a data transfer mechanism is differently applied as the rate of RTI service execution. A federate usually publishes or subscribes data when it starts. The federate constantly updates the data and modifies associated regions while it continues to advance its simulation time. Therefore, the proposed DDM design provides fast update or region modification in exchange of complex publish and subscribe services. We describe how to process the proposed DDM in IEEE 1516 HLA/RTI and experiment variable scenarios while modifying region, changing overlap ratio, and increasing data volume.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.3 s.30
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• pp.69-78
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• 2004

Since 1995, One of the NGIS(National Geographic Information System) projects, the underground utilities project, has been finished in 2003. The 19 cities in korea for this project will use underground utilities management system using underground utilities database focusing on water and sewage system. However, special expert, technical and experience problem in computer environment has not been had in working department for water and sewage management and maintenance for each local government. The management and maintenance by underground utilities database by manual method is getting lowered a data qualify of underground utilities database because of the data omitting, error in writing and securing of the lasted database. Therefore, in this study, Application test for field workers using a mobile tool and environment analysis of wireless communication in Korea and application test of GPS receiver for mobile tools had been processed and made a mobile working environment. The efficient management and maintenance method for underground utilities database has been developed an off-line method for modification and update of database about general work which has a high working frequency because of the limitation of wireless communication environment. Also, the emergency working has been applied for on-line method.