• ETRI Journal
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• v.22 no.3
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• pp.27-40
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• 2000

Recently, advanced information technologies have opened new possibilities for collaborative designs. In this paper, a web-enabled collaborative design environment is proposed, where the product data based on STandard for the Exchange of Product model data (STEP) is managed in a hierarchical database and the product metadata is used to efficiently search and utilize information scattered over the network. Several integrity constraints are depicted using EXPRESS to validate the combination of data from different sources. The knowledge represented as metadata and constraints on the interacting features differentiate this environment from previous ones. The collaborative conferencing system is also introduced to communicate and collaborate simultaneously among the related designed. As a result, the proposed environment allows the distributed designers to more efficiently obtain, exchange and communicate the design information throughout the design process.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.47-53
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• 2012

Sensor networks and car networks that have different structure from that of conventional TCP/IP network require extreme network environment due to frequent change of connectivity. Because such extreme network environment has characteristics like unreliable link connectivity, long delay time, asymmetrical data transfer rate, and high error rate, etc., it is difficult to perform normally with the conventional TCP/P-based routing. DTNs (delay and disruption tolerant network) was designed to support data transfer in extreme network environment with long delay time and no guarantee for continuous connectivity between terminals. This study suggests an algorithm that limits the maximum number of copying transferred message to L by improving the spray and wait routing protocol, which is one of the conventional DTNs routing protocols, and using the azimuth and density data of the mobile nods. The suggested algorithm was examined by using ONE, a DTNs simulator. As a result, it could reduce the delay time and overhead of unnecessary packets compared to the conventional spray and wait routing protocol.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.04a
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• pp.572-578
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• 1999

The product information is defined as the information that is obtained in the whole life cycle of a product from design and manufacturing to marketing and it carries out the important role under the changeful environment. It is necessary to use computers for efficient product data sharing. But, in practice, because of various product data types and heterogeneous computing environment, it is difficult to share the product information among different computer systems. This paper presents the methodology for sharing the product information without a hitch in he-terogeneous computing environment by using the international standard of the product information ISO-10303 STEP and CORBA.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.648-654
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• 2011

We can model marine uplink channel environment as time-correlated rician fading channel that has direct path and time varying reflected path. In this channel, error performance of uncoded system can be seriously degraded by multipath inteference. In this paper, we propose Concatenated Zigzag(CZZ) coded binary FSK signaling with noncoherent detection to improve error performance of uplink data in marine environment. CZZ code is a kind of channel coding scheme that is fast decodable as well as fast encodable. We have confirmed error performance of uplink data in marine environment can be improved dramatically through applying CZZ code.

• Korean Journal of Remote Sensing
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• v.31 no.4
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• pp.331-336
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• 2015

In this study, a numerical model developed for sunshine duration based on GIS data was used. This model considers blocking caused by topography and buildings and it is properly applicable to evaluation of sunshine duration environment in urban areas. The model reasonably well predicted the solar altitude and azimuth angels, compared to those provided by Korea Astronomy and Space Science Institute (KASI). The developed model was applied to evaluation of sunshine duration environment around the Seonleung Park located near a building-congested area in Seoul. The model well reproduced shadow caused by buildings and/or topography in the numerical domain at 09:00 on August 1, 2015. In addition, the model was applied to finding a suitable measurement sites for pyrheliometer around the Seonleung Park. The model was also usefully applied to finding a suitable site for pyrheliometer in an urban area.

• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.13-17
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• 2004

As the usage of wireless LAN becomes common in working environment, the number of database systems that support both wired and wireless users increases rapidly. The characteristics of wireless LAN that its speed is slow relatively comparing to wired network and the users in its environment connects to different communication points as they moves creates another challenge to be resolved in database systems. In the environment of hybrid communication systems, wired and wireless for voluminous data amount and a number of users, the two layer architecture of the conventional client-server database systems has limitation in the system performance. This is due to that server is the only point of data service in client-server database systems. In this paper, we discuss a new extended database system architecture that data services are distributed among servers and clients based on user database access patterns in order to improve system performance. We analyze the expected system performance by using simulation technique and prove the practical utilization of the system by demonstrating experimental results.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.701-702
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• 2006

In this paper, we embodied the environment monitoring system that can acquire correct data in real-time. And we used module that is 2.4GHz IEEE 802.15.4 / Zigbee network for radio communication between nodes. The nodes sense the data of temperature, humidity, illumination periodically. The nodes store the data in their buffer and transmit. We confirmed that the system is in real-time as it is changed instantly due to the varying environment by the simulation Therefore, we can construct the efficient and correct system as applied this system to monitor the environment.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1452-1455
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• 2008

In order to establish active and effective recycling plans on construction wastes, the study seeks to built unit generation data per construction waste types on each sector, prepare units data on urban construction waste generation and serve as meaningful data on the establishment of policies on construction waste recycling targeting urban regions. The significance of the study is on the establishment of construction waste recycling plan prior to generation, not as complementary measures on construction waste generated.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.375-379
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• 2016

Recently derived energy dissipation equation by Chamani(2008) and the profile function of the free overfall by Marchi(1993) were verified with present experiment data. The experiment was conducted in hydraulic laboratory, Hanyang University where the flume is 7m long and 0.44m wide, and the height of the drop structure is 0.205m. Water depth and free overfall profile data were collected using an ultra sonic distance sensor and photographic images. The time-averaged water depth data and the free overfall profile were analyzed to examine the energy dissipation pattern over the drop structure

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.75-78
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• 2017

This paper compares operational and network analysis of centralized and distributed repository for big data solutions in the IoT enabled Smart Grid environment. The comparative analysis clearly depicts that centralize repository consumes less memory consumption while distributed locality-based repository reduce network complexity issues than centralize repository in state-of-the-art Big Data Solution.