• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1377-1399
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• 2020

In search and rescue mission, micro aerial vehicles (MAVs) are typically used to capture image and video from an aerial perspective and transfer the data to the ground station. Because of the power limitation, a cluster of MAVs are required for a large search area, hence an ad-hoc wireless network must be maintained to transfer data more conveniently and fast. However, the unstable link and the intermittent connectivity between the MAVs caused by MAVs' movement may challenge the packet forwarding. This paper proposes a delay tolerant packet forwarding algorithm based on location estimation for MAV networks, called DTN_est algorithm. In the algorithm, ferrying MAVs are used to transmit data between MAVs and the ground station, and the locations of both searching MAVs and ferrying MAVs are estimated to compute the distances between the MAVs and destination. The MAV that is closest to the destination is selected greedy to forward packet. If a MAV cannot find the next hop MAV using the greedy strategy, the packets will be stored and re-forwarded once again in the next time slot. The experiment results show that the proposed DTN_est algorithm outperforms the typical DTN_geo algorithm in terms of packet delivery ratio and average routing hops.

• IE interfaces
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• v.22 no.3
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• pp.234-242
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• 2009

It is most important for distribution center in retail business to delivery commodities in a timely manner. Accordingly, many companies try to make distribution center effective using the Warehouse Management System(WMS) integrated legacy system. Also, the Customer Relationship Management(CRM) is the most typical paradigm in management lately. Even though the WMS and CRM are independent system of each other, WMS, coupled with CRM makes customer satisfied more effectively. In this paper, we proposed the methodology for inventory location after analyzing and applying customer buying pattern data in the CRM through the MBA(Market Basket Analysis), which is part of data mining. We used an example modeling a real distribution center in retail through a 3D simulation tool and examined correlation between commodities using customer buying pattern. After that, we applied it to the inventory location system through the MBA in an example. Finally, we identified decrease in the time for picking, which is the majority of distribution center. Besides, we proposed a simulation methodology before applying new methodology. Consequently, it removes potential errors in advance and makes a optimized inventory location system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.178-182
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• 2005

The proposed system in this paper is designed to provide users with a means of global location information using Orbcomm satellite communication and X.400 protocol. The system's two-way data transmission capabilities allow users to track mobile or fixed objects anywhere in the world via Internet. This study utilizes the X.400 protocol, and the SIP(Serial Interface Protocol) and self defined control protocol to implement data communication link in this paper. Data processor board connected to SC(Subscriber Communicator) is also designed and implemented to interface with GPS receiver. The experimental results of the proposed global position location system is evaluated through real-time experiments, and we have confirmed it works well according to the protocol designed in this paper.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.42-50
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• 2018

The majority of existing falling recognition techniques provide service by recognizing only that the falling occurred. However, it is important to recognize not only the occurrence of falling but also the situation before and after the falling, as well as the location of the falling. In this paper, we design and propose the falling notification service system to recognize and provide service. This system uses the acceleration sensor of the smartphone to recognize the occurrence of a falling and the situation before and after the falling. In order to check the location of falling, GPS sensor data is used in the Google Map API to map to the map. Also, a crosswalk map converted into grid-based coordinates based on the longitude and latitude of the crosswalk is stored, and the locations before and after falling are mapped. In order to reduce the connection speed and server overload for real-time data processing, fog computing and cloud computing are designed to be distributed processing.

• Journal of Environmental Impact Assessment
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• v.15 no.1
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• pp.45-52
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• 2006

The purpose of this study is to assess spatiotemporal variation of coastal water quality according to time and location changes. For this we developed numerical marine trophic index base on four water quality components (chlorophyll, suspended solids, dissolved inorganic nitrogen and phosphorus) and applied this index to the water quality data measured in the korean coastal zone for the 7-years period from 1997 to 2003. Water quality data are obtained only at selected sites even though they are potentially available at any location. Therefore, in order to estimate spatial variation of coastal water quality, it is necessary to estimate the unknown values at unsampled locations based on observation data. In this study, we used IDW (Inverse Distance Weighted) method to predict water quality components at unmeasured locations and applied marine trophic index to predicted values obtained by IDW interpolation. The results of this study indicate that marine trophic index and spatial interpolation are useful for understanding spatiotemporal characteristics of coastal water quality.

• Journal of Digital Contents Society
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• v.17 no.2
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• pp.81-88
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• 2016

The general frequent pattern mining considers frequency and support of items. To extract useful information, it is necessary to consider frequency and weight of items that reflects the changing of user interest as time passes. The suitable services considering time or location is requested by user so that the weighted mining method is necessary. We propose a method of weighted frequent pattern mining based on service ontology. The weight considering time and location is given to service items and it is applied to association rule mining method. The extracted rule is combined with stored service rule and it is based on timely service to offer for user.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.137-142
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• 2019

This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1689-1694
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• 2011

There are increasing customer's needs for safe operation and comfort of trains for the passengers as trains are getting fast and developed with advanced components. To meet the needs we developed the system which is able to prevent possible risk elements by transverse vibrations during the train operation. System records the amplitude data of trains vibration and location data from GPS antenna in real time. The system is composed of 5 different functioning modules as following GCPU, GGWD, GIFD, GAID and GPSD. GAID module is detecting amplitude value of vibration which is sensed by bogie hunting sensor's. GFID gets location information where vibration data is detected with GPS Antenna. Once those data is prepared, GCPU testify it's amplitude and decides whether it send those data. When it sends those recorded data, those data are sent to control unit by MVB communication. we expect that this information will help operation and maintenance engineers improve the safety train services. This paper explains train transverse Vibrations data recording system and its major functions which can measure the amplitude of trains's data during the operation and introduces the configuration for the system setup.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.3
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• pp.31-44
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• 2000

The purpose of this study is to show how could GIS along with digital maps and census data be used for scientific urban analysis and location analysis for a proposed project. Results are summarized as follows. First. after digital maps being completed, the census tract system being adopted, and major urban data being inputted in the computer file, GIS could be used intensively for various reliable urban analysis. With graphic statistical, and overlay functions of GIS, various physical and socio-economic characteristics of urban areas could be presented for analysis in the form of thematic and datapoint maps on the computer screen. Second, the locational analysis for a proposed project is a major part in the building permit review process, which tends to become disputable and time consuming as society become pluralized. Along with various GIS functions scientific decision-making methods could be developed, and the methods could play an important role for faster and scientific location analysis. As such, GIS would play an important role for faster and reliable urban analysis and location analysis and these functions finally would play important roles to improve public services and administration of local governments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.2
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• pp.160-167
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• 1987

This paper proposes a CS/MLBP(carrier sence/message and location based priority) reservation sheme in integrated data/voice local area networks. In this sceme reservation can be done with only 2 reservation bits regardless of the total number of stations in the network. Thus the reservation time is shorter than that of DSMA scheme(6) where reservation time is proportional to the logarithm of the total number of stations. Simulation results show that, as compared to DSMA scheme, this control scheme improves th delay-throughput characteristics of both the data and the voice traffic, reduces the lossrate of voice packet at heavy load. Results also show that the performance of the propoxed scheme is independant of the total number of the stations allowed.