• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.3
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• pp.81-90
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• 2012

Recently, with an increased social interest in new and renewable energy resources, together with rapid advancement in IT(information technology) and spatial information technology, there have recently been a lot of attempts to find out methods to make systematic and scientific use of information technology and spatial information technology, depending upon a fusion with GIS(Geographic Information System) spatial information technology in the field of new and renewable energy. This paper developed a suitability analysis system to conduct a correct and precise analysis of an ideal place for wind energy facilities in comprehensive consideration of topographic, economic, and cultural environments. It also used recent spatial information technology including 3D GIS to develop a supportive system for an analysis and decision making of an ideal place for 3D Web GIS-based wind energy facilities like a precise field information implementation, a 3D result display, a 3D object implementation, simulation, and so on. These systems make it possible to build scientific new-renewable energy facilities, to collect, manage and analyze information in an accurate and quantitative manner. In addition, they help serve as a turning point for the construction of a real-time information supply system. Furthermore, they can support rational decision making by making it possible to analyze a variety of forms of field information through building a system for the management of 3D image-based information on new-renewable energy resources.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.323-335
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• 2016

The main reason of marine casualties is the human error in respect of ship's operation. The human error of officers in charge of a navigational watch is related to their abilities to handle of navigational equipment. Navigational devices play a key role to help officers decide what to do for safe navigation. Thus, the abilities to handle of navigational equipment mean not only operation of devices but also entire understanding of the system such as interpretation of information obtained from devices, appropriate use of information considering navigational circumstance. Qualification of seafarers is in accordance with STCW and detailed training courses for their qualification are provided by IMO model course series. Recently, ships engaged on international voyages shall be fitted with an ECDIS not later than the first survey on or after 1 July 2018. As increasing use of ECDIS on ships, marine casualties related to ECDIS are on the rise. The primary causes of the accidents are lacking understanding of ECDIS system, wrong presentation of information on display, wrong safety setting by seafarers who use ECDIS, using small-scale chart and missing charts update. As a result of these primary causes, some problems like wrong route planning and use of limited or omitted information occur. It could be happening by inappropriate seafarers' training which is not sufficient to support improving abilities of officers to handle navigational equipment. For efficient training, it is need to develop training courses. Applying full mission simulation system to seafarers' training courses with case studies and best practices which are well-constructed scenarios based on true marine casualties can increase the effect of training. To use the simulation system, it is possible that seafarers are trained under condition that closely resemble real situation. It should be considered that IMO model course be revised depending on the level of seafarers also. It could be helpful for increasing seafarers' abilities of equipment operation in place of accumulation of experience spending much time. In the short term, effort of training courses improvement for seafarers is needed and long term, it should be tried to provide stable system and services relate to ECDIS.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.171-174
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• 2005

According as marine leisure industry has developed and the demand of leisure culture has increased rapidly, a desire about service which supply marine safety and connect marine information is enlarging. The performance of personal mobile device has improved and been evolved by composition terminal. So, it became possible that storage and expression of multimedia information as well as simple communication facility. Domestic wireless internet has given development strain to developer and contents Provider(CP) because of different platform. And this has become hindrance factor of wireless internet activation. But, recently, the use of WIPI(Wireless Internet Platform for Interoperability), the wireless internet standard platform, could use different wireless application programs and also guarantee the independency for hardware. We wish to develop contents of download form that supply geographic information of Electronic Navigational Chart(ENC) in the marine that is digitalized to carrying along terminal of WIPI base and various informations for marine leisure. For this, DB that offer ENC and additional information should be constructed. Also, we need server (CPS; Contents provider Server) that offer required contents. In this paper, we design web retrieval agent which store request information to database. When consumer required necessary information through personal mobile device, CPS can inform that by real time. So, we wish to develop agent component that parse informations in various World Wide Webs, and store to database.

• The KIPS Transactions:PartD
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• v.17D no.1
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• pp.1-8
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• 2010

Association rule mining techniques enable us to acquire knowledge concerning sales patterns among individual items from voluminous transactional data. Certainly, one of the major purposes of association rule mining is utilizing the acquired knowledge to provide marketing strategies such as catalogue design, cross-selling and shop allocation. However, this requires too much time and high cost to only extract the actionable and profitable knowledge from tremendous numbers of discovered patterns. In currently available literature, a number of interest measures have been devised to accelerate and systematize the process of pattern evaluation. Unfortunately, most of such measures, including support and confidence, are prone to yielding impractical results because they are calculated only from the sales frequencies of items. For instance, traditional measures cannot differentiate between the purchases in a small basket and those in a large shopping cart. Therefore, some adjustment should be made to the size of market baskets because there is a strong possibility that mutually irrelevant items could appear together in a large shopping cart. Contrary to the previous approaches, we attempted to consider market basket's size in calculating interest measures. Because the devised measure assigns different weights to individual purchases according to their basket sizes, we expect that the measure can minimize distortion of results caused by accidental patterns. Additionally, we performed intensive computer simulations under various environments, and we performed real case analyses to analyze the correctness and consistency of the devised measure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.637-644
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• 2004

This paper proposed and implemented the adaptive transmission middleware for video streaming, which is able to support the adaptive transmission of video data to the fluctuating changes of network environment in the packet-based network and the properties of transmitted video data. The adaptive transmission middleware is made up SR-RTP-based transfer module and TFRC(TCP Friendly Rate Control)-based transfer-rate control module. The SR-RTP-based transfer module supports RTP-based real-time transfer of video data and packet retransmission scheme retransmitting the high-priority packets selectively in the damaged video data to reduce the error induced by the packet loss. Sharing the transmission bandwidth of network with the TCP-based data transfer, the TFRC-based transfer-rate control module controls the transfer rate of video data according to the most allowable transmission bandwidth in the network, so that the transfer rate is controlled adaptively to the fluctuating changes of transmission bandwidth. This paper, for the experiment, applied the adaptive transmission middleware to video streaming in the external Internet environment, and analyzed the effective frame transfer rate and the degree of the streaming jitter to evaluate the performance of packet-loss recovery and adaptive transfer rate control. In the external Internet environment where the packet-loss rate is high a bit, the relatively high streaming performance was showed compared with the case that didn't apply the adaptive transmission middleware.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1021-1030
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• 2010

In the sensor network, many tiny nodes construct Ad-Hoc network using wireless interface. As this type of system consists of thousands of nodes, managing each sensor node in real world after deploying them is very difficult. In order to install the sensor network successfully, it is necessary to verify its software using a simulator beforehand. In fact Sensor network simulators require high fidelity and timing accuracy to be used as a design, implementation, and evaluation tool of wireless sensor networks. Cycle-accurate, instruction-level simulation is the known solution for those purposes. In this paper, we developed an instruction-level sensor network simulator for Telos sensor node as named TeloSlM. It consists of MSP430 and CC2420. Recently, Telos is the most popular mote because MSP430 can consume the minimum energy in recent motes and CC2420 can support Zigbee. So that TeloSlM can provide the easy way for the developers to verify software. It is cycle-accurate in instruction-level simulator that is indispensable for OS and the specific functions and can simulate scalable sensor network at the same time. In addition, TeloSlM provides the GUI Tool to show result easily.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.831-838
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• 2001

Mobile information service aims to provide some degree of effective information for real life activities of mobile users. Due to the user mobility and actual realism, it becomes very important technical issue to support an adaptive information service methodology to current situations of the terminal and/or user. This paper deals with a prefetching scheme for location-aware, out of the various context-aware which can be considered in mobile information service. It makes use of the velocity-based mobility model to shape the terminal and/or user's mobility behavior. Based on the moving speed and direction, the prefetching zone is proposed to define the number of prefetched information, so as to limit effectively the prefetched information whilst to preserve the location-aware adaptability. Using a simulator, the proposed scheme has been evaluated in the effectiveness point of view. The idea in this paper is expected to be able to extended to the other mobile service contexts, such as service time, I/O types of mobile terminals, network bandwidth.

• ALGAE
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• v.35 no.1
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• pp.45-59
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• 2020

To investigate the spatio-temporal distributions of the mixotrophic dinoflagellate Yihiella yeosuensis in Korean coastal waters and its grazing impact on prey populations, water samples were seasonally collected from 28 stations in the East, West, and South Seas of Korea and Jeju Island from April 2015 to October 2018. The abundances of Y. yeosuensis in the water samples were quantified using quantitative real-time polymerase chain reaction (qPCR). Simultaneously, the physical and chemical properties of water from all sampled stations were determined, and the abundances of the optimal prey species of Y. yeosuensis, the prasinophyte Pyramimonas sp. and the cryptophyte Teleaulax amphioxeia, were quantified using qPCR. Y. yeosuensis has a wide distribution, as is reflected by the detection of Y. yeosuensis cells at 23 sampling stations; however, this distribution has a strong seasonality, which is indicated by its detection at 22 stations in summer but only one station in winter. The abundance of Y. yeosuensis was significantly and positively correlated with those of Pyramimonas sp. and T. amphioxeia, as well as with water temperature. The highest abundance of Y. yeosuensis was 48.5 cells mL^-1 in Buan in July 2017, when the abundances of Pyramimonas sp. and T. amphioxeia were 917.6 and 210.4 cells mL^-1, respectively. The growth rate of Y. yeosuensis on Pyramimonas sp., calculated by interpolating the growth rates at the same abundance, was 0.49 d^-1, which is 37% of the maximum growth rate of Y. yeosuensis on Pyramimonas sp. obtained in the laboratory. Therefore, the field abundance of Pyramimonas sp. obtained in the present study can support a moderate positive growth of Y. yeosuensis. The maximum grazing coefficient for Y. yeosuensis on the co-occurring Pyramimonas sp. was 0.42 d^-1, indicating that 35% of the Pyramimonas sp. population were consumed in 1 d. Therefore, the spatio-temporal distribution of Y. yeosuensis in Korean coastal waters may be affected by those of the optimal prey species and water temperature. Moreover, Y. yeosuensis may potentially have considerable grazing impacts on populations of Pyramimonas sp.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.5
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• pp.401-415
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• 2005

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. Transcoding servers transcode the source media to the target media within corresponding grades and provide QoS in real-time. In particular, an effective load balancing policy for transcoding servers is inevitable to support QoS for large scale mobile users. In this paper, the resource weighted load distribution policy is proposed for a fair load balance and a more scalable performance in cluster-based transcoding servers. Our proposed policy is based on the resource weighted table and number of maximum supported users, which are pre-computed for each pre-defined grade. We implement the proposed policy on cluster-based transcoding servers and evaluate its fair load distribution and scalable performance with the number of transcoding servers.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.146-154
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• 2019

Recently, a system has been developed and applied to establish and utilize HD maps through R&D. The biggest problem, however, is the lack of a proper HD map update system, which requires the development and adoption of such a system as soon as possible. In addition, in the case of updating HD maps for automated driving, integrity and accuracy of maps are required for safe driving, so an test of these technologies and data quality is required. In April 2018, the Ministry of Land, Infrastructure and Transport implemented a project to 'Develop Technology to Demonstrate and Share the Instant Road Change Detection and Update Technology for automated driving. This paper analyzed the technology for updating map based on the investigation and analysis of relevant technology trends for the development of integrated demonstration and sharing technology of road change rapid detection and updating map technology, and put forward the criteria for road change rapid detection, integrated quality verification of update technology. It is expected that the results of this study will contribute to quality assurance of HD maps that support safety driving for automated vehicles.