• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1623-1631
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• 2022

Since oil spills can be a significant threat to the marine ecosystem, it is necessary to obtain information on the current contamination status quickly to minimize the damage. Satellite-based detection of marine oil spills has the advantage of spatiotemporal coverage because it can monitor a wide area compared to aircraft. Due to the recent development of computer vision and deep learning, marine oil spill detection can also be facilitated by deep learning. Unlike the existing studies based on Synthetic Aperture Radar (SAR) images, we conducted a deep learning modeling using PlanetScope optical satellite images. The blind test of the DeepLabV3+ model for oil spill detection showed the performance statistics with an accuracy of 0.885, a precision of 0.888, a recall of 0.886, an F1-score of 0.883, and a Mean Intersection over Union (mIOU) of 0.793.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.41-48
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• 2012

Objective: Companies want to expand their business by providing their services at other devices and new services based upon existing services. Therefore, they look for building brand identity by providing same experience throughout devices and services. Background: Many services are available to use at multiple devices including mobile phones, tablet, personal computers, and televisions, thanks to proliferation of n-screen and cloud technology. Method: It was discussed that consistency, which emphasizes the regularity and has been one of essential aspects of user interface design, seems not effective to be applied to n-screen services, owing to different screen size, input and output peripherals, usage environment and users' attitude. Results: A new definition of same experience among different devices and services, called coherence, was introduced and abstraction levels of user interfaces were proposed as the denominator of defining coherence. Then types of users' task knowledge at each abstraction level were discussed with examples. Conclusion: This paper concluded by discussing design requirements for designing coherent user interfaces among devices and services.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.446-459
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• 2016

In this paper, we propose virtual direction multicast (VDM) for video multicast applications on peer-to-peer overlay networks. It locates the end hosts relative to each other based on a virtualized orientation scheme using real-time measurements. It builds multicast tree by connecting the nodes, which are estimated to be in the same virtual direction. By using the concept of directionality, we target to use minimal resources in the underlying network while satisfying users' quality expectations. We compare VDM against host multicast tree protocol.We simulated the protocol in a network simulator and implemented in PlanetLab. Results both from simulation and PlanetLab implementation show that our proposed technique exhibits good performance in terms of defined metrics.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.61-67
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• 2011

Smart TV System will lead to drastic change of communication and media industries as one of the emerging next generation network services. However, when the number of concurrent users increases rapidly, the issue of service quality degradation occurs because providing services to many users simultaneously stresses both the server and the network. The server limitation can be circumvented by deploying server clusters. but the network limitation is far less easy to cope with, due to the difficulty in determining the cause and location of congestion and in provisioning extra resources. In order to alleviate these problems, a number of schemes have been developed. Prior works mostly focus on reducing user-centric performance metrics of individual connection, such as the round-trip time(RTT), downloading time or packet loss rate, but tend to ignore the network loads caused by the concurrent connections or global network load balance. In this work, we make an in-depth investigation on the issue of user grouping for massive Smart TV services through simulations on actual Internet test-bed, PlanetLab.

• Information Systems Review
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• v.17 no.3
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• pp.135-157
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• 2015

Mobile giving platform is a new type of giving platform which offers donation service through mobile application. Mobile giving platform has developed differently from offline giving platform in the way that induces continuous donation. The purpose of this study is to investigate why mobile giving platform has adopted different strategy, and how it leads to continuous contribution. We conducted a case study with two successful mobile giving platforms; Bigwalk and Tree Planet. The analysis of the strategy is based on the construal level theory which explains the relationship between psychological distance and construal level. The result shows that the users' psychological distance toward giving platform has decreased with the environmental change, offline to mobile. Consequently the mobile giving platform offers services which form low level of construal for encouraging continuous participation. This finding suggests the importance of offering suitable construal level in services, and design guideline for mobile giving platforms.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.06a
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• pp.29-29
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• 2004

Long term observational analysis by climatologists has confirmedthat the global warming is no longer a topic of debate among scientists andpolicy makers. According to the report of IPCC-2001 (Intergovernmental Panelon Climate Change), the global mean surface air temperature is increasinggradually. The reported increase of mean temperature is by 0.6 degree in the end of twentieth century. This could represent severe threat for propertylosses especially due to increase in the number of extreme weather arising out of global warming. period of model integration from 2001 to 2100 using output of ECHAM4/HOPE-G of Max Planet Institute of Meteorology (MPI) for IPCC SRES (Special Report on Emission Scenarios). The main results of this study indicate increase of surface air temperature by 6.20C and precipitation by 2.6% over Korea in the end of 21st century. Simulation results also show that there is increase in daily maximum and minimum temperatures while decrease in diurnal temperature range (DTR). DTR changes are diminished mainly due to relatively rapid increase of daily minimum temperature than that of daily maximumtemperature. It has been observed that increase in precipitation amount anddecrease in the number of rainy days lead to increase of pre precipitationintensity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.730-739
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• 2013

More than 30% of energy in Korea was spent in lighting part and then the consumption level and $CO_2$ emission will be increase from now. In this like situation, control-system construction for street-lamp of a smart grid-based that it has important meaning. Nowadays as a result, as an trying to utilize using Power-line-network communication modem and application a terminal in industrial fields, in this paper, we are want to implement the Power-line-network communication control system of PC-based. Therefore it will be use varied communication test-equipment and tools through the system. For experimentation, using the MODEM was able to use Planet production of based on the ZIC protocol and then the application program use the LabView. The result is primarily focused on equipments control by the PLC, and that we are able to perform each test with PLC equipment for experiment it.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.125-130
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• 2012

Objective: This paper discusses how service design is related to two well-known disciplines, interaction design and cognitive systems engineering, which are applied to the design of software, websites and mobile phones, and the design of control room of nuclear power plants and cockpit control, respectively. Background: Service design has been spotlighted recently due to its promisingness to service industry. Successful cases of service design are widely shared among designers. Service design, however, is treated as practice rather than a discipline. Method: It was discussed that it is important to consider the interaction between customers and services as in interaction design, and some domains are complex enough and have functional limitation as in cognitive systems engineering. Results: Models and design tools of the disciplines are introduced and applied to service design practices. Conclusion: It was concluded that service design has the characteristics of both interaction design and cognitive systems engineering.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.384-386
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• 2012

최근 네트워크 상의 패킷은 대부분 컨텐츠가 주를 이룬다. 이러한 추세를 네트워크 계층에서 지원하기 위해 미래 인터넷 환경으로써 여러 가지 컨텐츠 중심의 아키텍쳐들이 제안되었다. 제안된 아키텍쳐들은 컨텐츠가 저장된 위치보다는 컨텐츠 자체에 초점을 둔 미래지향적인 인터넷 환경이다. 대표적인 미래 인터넷 환경으로는 컨텐츠 중심 네트워킹 (CCN)이 있다. 하지만 지금까지 제안된 컨텐츠 중심의 아키텍쳐들은 링크나 노드의 불량문제에 대해서는 다루지 않고 있다. 특히, 컨텐츠 중싱 네트워킹 (CCN)에서는 패킷이 전송되는 정해진 경로에서 링크나 노드의 불량이 발생하면 그 경로를 거쳐야 하는 모든 패킷의 손실이 발생한다. 제안하는 기법에서는 이를 막기 위해 노드들이 불량을 감지하고, 불량이 발생하는 즉시 새로운 경로로 패킷을 우회하게 함으로써 불량에 대한 대비가 가능하도록 한다. 제안하는 기법의 효율성을 증명하기 위해 전세계적인 오버레이 네트워크인 PlanetLab에 적용하여 성능 평가를 수행한다.

• ETRI Journal
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• v.28 no.6
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• pp.709-720
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• 2006

In this paper, we suggest a simple and efficient multiple-forwarder-based file distribution method which can work with a tree-based application layer multicast. Existing multiple-forwarder approaches require high control overhead. The proposed method exploits the assumption that receivers join a session at different times. In tree-based application layer multicast, a set of data packets is delivered from its parent after a receiver has joined but before the next receiver joins without overlapping that of other receivers. The proposed method selects forwarders from among the preceding receivers and the forwarder forwards data packets from the non-overlapping data packet set. Three variations of forwarder selection algorithms are proposed. The impact of the proposed algorithms is evaluated using numerical analysis. A performance evaluation using PlanetLab, a global area overlay testbed, shows that the proposed method enhances throughput while maintaining the data packet duplication ratio and control overhead significantly lower than the existing method, Bullet.