• The KIPS Transactions:PartC
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• v.8C no.5
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• pp.573-584
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• 2001

Policy-Based Network Management (PBNM) architecture is to meet various needs of network users and to provide effective management facilities in distributed and large scale networks to network managers. In PBNM, network managers perform network management operations by stipulating a set of rules rather than control each network component. On the other hand, providing security services such as authentication, privacy of messages as well as a new flexible and extensible administration framework, SNMPv3 enables network managers to monitor and control the operation of network components more secure way than ever before. Despite of its enhanced security services, SNMPv3 has difficulties in managing distributed, large-scaled network because it does not provide centralized security management facilities. In this paper, we propose a new security model called Role-based Security Management model (RSM) with security management policy to support scalable and centralized security management for SNMP-based networks. Also, the structure and the operation of the security system as well as the efficiency analysis of RSM in terms of security management are also described.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.3
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• pp.113-120
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• 2018

In this study, we proposed a monitoring system for identifying and handling faulty sensing stream data on manufacturing equipments where low-cost sensors can be safely used. Low cost sensors will lessen the cost of implementing distributed monitoring system, but suffer from sensor noises and inaccurate sensed data. Therefore, a distributed monitoring system with low cost sensors should identify faulty signal data as either of sensor fault or machine fault, and filter out faulty signals from sensing fault. To this end, we adopted a fourier transform based diagnostic approach mixed with a weighed moving averaging method, in order to identify faulty signals. We measured how effective our approach is and found out our approach can filter out one-third faulty signals from our experimental environment. In addition, we attached wireless communication modules to reduce sensor and network installation cost. To handle massive sensor data efficiently, we employed unstructured data format with NoSQL based database.

• Korean Journal of Remote Sensing
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• v.29 no.2
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• pp.263-274
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• 2013

In this study we evaluated the hydrological applicability of multi-satellite precipitation estimates. Three high-resolution global multi-satellite precipitation products, the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), the Global Satellite Mapping of Precipitation (GSMaP), and the Climate Precipitation Center (CPC) Morphing technique (CMORPH), were applied to the Coupled Routing and Excess Storage (CREST) model for the evaluation of their hydrological utility. The CREST model was calibrated from 2002 to 2005 and validated from 2006 to 2009 in the Chungju Dam watershed, including two years of warm-up periods (2002-2003 and 2006-2007). Areal-averaged precipitation time series of the multi-satellite data were compared with those of the ground records. The results indicate that the multi-satellite precipitation can reflect the seasonal variation of precipitation in the Chungju Dam watershed. However, TMPA overestimates the amount of annual and monthly precipitation while GSMaP and CMORPH underestimate the precipitation during the period from 2002 to 2009. These biases of multi-satellite precipitation products induce poor performances in hydrological simulation, although TMPA is better than both of GSMaP and CMORPH. Our results indicate that advanced rainfall algorithms may be required to improve its hydrological applicability in South Korea.

• Journal of Korea Spatial Information System Society
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• v.8 no.2 s.17
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• pp.91-107
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• 2006

To handling the extreme situation that must manage positional information of a very large volume, at least millions of moving objects. A cluster-based sealable distributed computing system architecture, called the GALIS which consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone, was proposed. In this paper, we proposed a valid time management and time-zone shifting scheme, which are essential in realizing the long-term location data subsystem of GALIS, but missed in our previous prototype development. We explain how to manage valid time of moving objects to avoid ambiguity of location information. We also describe time-zone shifting algorithm with three variations, such as Real Time-Time Zone Shifting, Batch-Time Zone Shifting, Table Partitioned Batch-Time Zone Shifting, Through experiments related with query processing time and CPU utilization, we show the efficiency of the proposed time-zone shifting schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1094-1103
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• 2012

Recently, software industry regarding national defense increases system development of distributed simulation system of M&S based to overcome limit of resource and expense. It is one of key technologies for offering of mutual validation among objects and reuse of objects which are discussed for developing these systems. RTI, implementation of HLA interface specification as software providing these technologies uses Federation Object Model for exchanging information with joined federates in the federation and each federate has a characteristic that is supposed to have identical FOM in the federation. This technology is a software which is to provide the core technology which was suggested by the United state's military M&S standard framework. Simulator, virtual simulation, and inter-connection between military weapons system S/W which executes on network which is M&S's core base technology, and it is a technology which also can be used for various inter-connection between S/W such as game and on-line phone. These days although RTI is used in military war game or tactical training unit field, there is none in Korea. Also, it is used in mobile-game, distribution game, net management, robot field, and other civilian field, but the number of examples are so small and informalized. Through this developing project, we developed the core technique and RTI software and provided performance of COTS level to improve communication algorithms.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.2
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• pp.85-97
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• 2011

Wireless sensor networks have emerged as one of the key enabling technologies for ubiquitous computing since wireless intelligent sensor nodes connected by short range communication media serve as a smart intermediary between physical objects and people in ubiquitous computing environment. We recognize the wireless sensor network as a massively distributed and deeply embedded system. Such systems require concurrent and asynchronous event handling as a distributed system and resource-consciousness as an embedded system. Since the operating environment and architecture of wireless sensor networks, with the seemingly conflicting requirements, poses unique design challenges and constraints to developers, we propose a very new operating system for sensor nodes based on finite state machine. In this paper, we clarify the design goals reflected from the characteristics of sensor networks, and then present the heart of the design and implementation of a compact and efficient state-driven operating system, SenOS. We describe how SenOS can operate in an extremely resource constrained sensor node while providing the required reactivity and dynamic reconfigurability with low update cost. We also compare our experimental results after executing some benchmark programs on SenOS with those on TinyOS.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.1-22
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• 2018

The purpose of this study is to provide the baseline data for conservation and management of Korean forest ecosystem by surveying and analyzing the vascular plants distributed from Gitdaebaegibong to Cheonghwasan in Baekdudaegan Mountains. The results are as follows. The numbers of vascular plants in the whole survey section were summarized as 771 taxa including 103 families, 379 genera, 623 species, 4 subspecies, 121 varieties and 23 forms. There were 377 taxa in A-section, 395 taxa in B-section, 278 taxa in C-section, 325 taxa in D-section, 534 taxa in E-section, and 406 taxa in F-section. The rare plants were 32 taxa including Megaleranthis saniculifolia, Rodgersia podophylla, Iris ensata var. spontanea, and Gastrodia elata. In IUCN Red List categories, there were 1 taxon of CR, EN, and DD each, 11 taxa of the VU, and 18 taxa of the LC. The Korean endemic plants were 26 taxa including Asarum versicolor, Clematis fusca var. coreana, Vicia chosenensis, Stewartia pseudocamellia, Carex okamotoi, and Luzula sudetica var. nipponica. The specific plants by floristic region were 143 taxa including 3 taxa of grade V, 12 taxa of grade IV, 41 taxa of grade III, 42 taxa of grade II, and 45 taxa of grade I. The naturalized plants were 41 taxa including Rumex crispus, Ailanthus altissima, Erechtites hieracifolia, Erigeron annuus, and Poa pratensis. The invasive alien plants were 4 taxa including Rumex acetocella, Sicyos angulatus, Ambrosia artemisiifolia, and Aster pilosus. The plants adaptable to climate change were 43 taxa including 14 taxa of endemic plants, 2 taxa of southern plants, and 27 taxa of northern plants.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.79-91
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• 2008

Recently, with highly Interest In Location-Based Service(LBS) utilizing location data of moving objects, the GALIS(Gracefully Aging Location Information System) which is a cluster-based distributed computing architecture was proposed as a more efficient location management system of moving objects. In the SLDS(Short-term location Data Subsystem) which Is a subsystem of the GALIS, since the SDP(Short-term Data Processor) Master transmits current location data and queries to every SDP Worker, the SDP Master reassembles and sends query results produced by SDP Workers to the client. However, the services are suspended during the SDP Master under failure and the response time to the client is increased if the load is concentrated on the SDP Master. Therefore, in this paper, the extended SLDS was designed and implemented to solve these problems. Though one SDP Master is under failure, the other can provide the services continually, and so the extended SLDS can guarantee the high reliability of the SLDS. The extended SLDS also can reduce the response time to the client by enabling two SDP Masters to perform the distributed query processing. Finally, we proved high reliability and high availability of the extended SLDS by implementing the current location data storage, query processing, and failure takeover scenarios. We also verified that the extended SLDS is more efficient than the original SLDS through the query processing performance evaluation.

• Journal of Environmental Impact Assessment
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• v.28 no.4
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• pp.347-372
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• 2019

The purpose of this study is to provide the basic data for management of the ecosystem of Baekdudaegan Mountains by surveying and analysing the vascular plants distributed from Hyangrobong area to Guryongryeong area. The numbers of vascular plants in the whole survey areas were summarized as 633 taxa including 95 families, 321 genera, 549 species, 4 subspecies, 70 varieties, and 10 forms. There were 285 taxa in Hyangrobong area, 256 taxa in Masanbong area, 318 taxa in Mt. Seoraksan area, 281 taxa in Mt. Jeombongsan area, 173 taxa in Bukamryeong and Ohsaekcheon valley area, 197 taxa in Soenadeuri area, 203 taxa in Yeongarigol area, and 168 taxa in Guryongryeong area. The endangered species were 2 taxa including Leontice microrrhyncha and Smilacina bicolor. The rare plants were 39 taxa including Pinus pumila, Halenia corniculata, Juniperus chinensis var. sargentii, and so forth. In IUCN Red List categories, there were 2 taxa of CR, 7 taxa of EN, 10 taxa of VU, 18 taxa of LC, and 2 taxa of DD. The Korean endemic plants were 23 taxa including Salix koriyanagi, Anemone koraiensis, Lespedeza maritima, Cirsium setidens, Saussurea seoulensis, Carex okamotoi, and so forth. The plants adaptable to climate change were 48 taxa including 17 taxa of endemic plants, 1 taxon of southern plant, and 30 taxa of northern plants. The naturalized plants were 32 taxa including Fallopia dumetorum, Cerastium glomeratum, Papaverrhoeas, Bidensfrondosa, Lolium perenne, and so forth. The invasive alien plants were 3 taxa including Rumex acetocella, Ambrosia artemisiifolia, and Ambrosia trifida.

• Journal of Internet Computing and Services
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• v.23 no.3
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• pp.21-33
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• 2022

This paper is to suggest the secure secret sharing system in order to outstandingly reduce the damage caused by the leakage of the corporate secret. This research system is suggested as efficient P2P distributed system kept from the centrally controlled server scheme. Even the bitcoin circulation system is also based on P2P distribution scheme recenly. This research has designed the secure circulation of the secret shares produced by Threshold Shamir Secret Sharing scheme instead of the shares specified in the torrent file using the simple, highly scalable and fast transferring torrent P2P distribution structure and its protocol. In addition, this research has studied to apply both Shamir Threshold Secret Sharing scheme and the securely strong multiple user authentication based on Collaborative Threshold Autentication scheme. The secure transmission of secret data is protected as using the efficient symmetric encryption with the session secret key which is safely exchanged by the public key encryption. Also it is safer against the leakage because the secret key is effectively alive only for short lifetime like a session. Especially the characteristics of this proposed system is effectively to apply the threshold secret sharing scheme into efficient torrent P2P distributed system without modifying its architecture of the torrent system. In addition, this system guaranttes the confidentiality in distributing the secret file using the efficient symmetric encryption scheme, which the session key is securely exchanged using the public key encryption scheme. In this system, the devices to be taken out can be dynamically registered as an user. This scalability allows to apply the confidentiality and the authentication even to dynamically registerred users.