• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.378-383
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• 2000

Pinus sylvestris plantations in the Eifel mountains, Germany, were studied and classified phytosociologically. Ecological characteristics(soil, natural regeneration & succession) of the plant communities classified were analyzed and described with emphasis on the forest management. According to soil and topographic characteristics, this plantations were divided into four categories ; Vaccinium myrtillus-Pinus sylvestris community of the adequate moisture area, Pteridium aquilium-Pinus sylvestris community of the moisture area, Molinia caerulea-Pinus sylvestris community of the hardened soil layer B and Festuca tenuifolia-Pinus sylvestris of the dry area. Tree species growing below the shrub layer was analyzed. The results were considered as Vaccinium mytillus-Pinus sylvestris, Pteridium aquline-Pinus sylvestris and Molinia caerulea-Pinus sylvestris will be changed into Fagus sylvatica forest following Quercus forest, and Festuca tenuifilia-Pinus sylvestris will be changed into Pinus sylvestris-dominated climax forest.

• Convergence Security Journal
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• v.15 no.7
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• pp.75-84
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• 2015

In an "NTFS Index Record Data Hiding" method messages are hidden by using file names. Windows NTFS file naming convention has some forbidden ASCII characters for a file name. When inputting Hangul with the Roman alphabet, if the forbidden characters for the file name and binary data are used, the codes are convert to a designated unicode point to avoid a file creation error due to unsuitable characters. In this paper, the problem of a file creation error due to non-admittable characters for the file name is fixed, which is used in the index record data hiding method. Using Hangul with Roman alphabet the characters cause a file creation error are converted to an arbitrary unicode point except Hangul and Roman alphabet area. When it comes to binary data, all 256 codes are converted to designated unicode area except an extended unicode(surrogate pairs) and ASCII code area. The results of the two cases, i.e. the Hangul with Roman alphabet case and the binary case, show the applicability of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.1-10
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• 2003

An EPON which is going on standardization in IEEE 802.3ah, is tree topology consists of a OLT and multiple ONU using passive optical components, so this network is susceptible to variable security threats - eavesdropping, masquerading, denial of service and so on. In this paper, we design a security protocol supporting authentication and confidentiality services in MAC layer in order to prevent these security threats and to guarantee secure data exchange The designed security protocol introduce public-key based authentication and key management protocols for efficient key management, and choose Rijndael algorithm, which is recent standard of AES, to provide the confidentiality of EPON Proposed authentication and key management protocols perform authentication and public-key exchange at a time, and are secure protocols using derived common cipher key by exchanging public random number To implement the designed security protocol, we propose the procedures of authentication and public-key exchange, session key update, key recovery. This proposed protocol is verified using unknown session key, forward secrecy, unknown key-share, key-compromise impersonation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1295-1304
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• 2010

This paper proposes a fault-tolerant data aggregation which provides energy efficient and reliable data collection in wireless sensor networks. The traditional aggregation scheme does not provide the countermeasure to packet loss or the countermeasure scheme requires a large amount of energy. The proposed scheme applies caching and re-transmission based on the track topology to the adaptive timeout scheduling. The proposed scheme uses a single-path routing based on the traditional tree topology at normal, which reduces the dissipated energy in sensor nodes without any countermeasure against packet loss. The proposed scheme, however, retransmits the lost packet using track topology under event occurrences in order to fulfill more accurate data aggregation. Extensive simulation work under various workloads has revealed that the proposed scheme decrease by 8% in terms of the dissipated energy and enhances data accuracy 41% when the potential of event occurrence exists as compared with TAG data aggregation. And the proposed scheme decrease by 53% in terms of the dissipated energy and shows a similar performance in data accuracy when the potential of event occurrence exists as compared with PERLA data aggregation.

• Korean Journal of Plant Taxonomy
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• v.40 no.3
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• pp.186-191
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• 2010

Four unrecorded species (Barbella flagellifera, Isothecium hakkodense, Mnium orientale and Fissidens gardneri) and with one unrecorded genus, Barbella, are reported new to the Korean moss flora. B. flagellifera (Meteoriaceae) was found on a tree at alt. 300-350 m of parasitic Seogeomun-oreum Volcano on Jeju Island. The species are mainly distributed in subtropic regions. I. hakkodense (Lembophyllaceae) was found around the top of Seongin-bong on Ulleung Island. This species is similar to I. subdiversiforme, however, it can be distinguished by the morphologies of branch leaves and alar cells. M. orientale (Mniaceae) was collected from Mt. Jiri. This is similar to M. heterophyllum, however, it can be distinguished by plant size, number of teeth in leaf margin and cell size on leaf. F. gardneri (Fissidentaceae) was found along the valley of Mt. Palyeong, Jeollanam Province. This species is similar to F. obscurirete, but distinguished by the size of the plants and their leaves as well as the costal lengths of the leaves.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.71-79
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• 2006

Address lookup is an essential function in the Internet routers, and it determines overall router performance. In this paper, we have thoroughly investigated the binary-search-based address lookup algorithms and proposed a new algorithm based on binary search on prefix lengths. Most of the existing binary search schemes perform binary search on prefix values, and hence the lookup speed is proportional to the length of prefixes or the log function of the number of prefixes. The previous algorithm based on binary search on prefix lengths has superior lookup performance than others. However, the algorithm requires very complicated pre-computation of markers and best matching prefixes in internal nodes since naive binary search is not possible in their scheme. This complicated pre-computation makes the composition of the routing table and incremental update very difficult. By using leaf-pushing, the proposed algorithm in this paper removes the complicated pre-computation of the Previous work in performing the binary search on prefix lengths. The performance evaluation results show that the proposed scheme has very good performance in lookup speed compared with previous works.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.349-359
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• 2004

To provide multicasting service, several multicast protocols for mobile hosts have been proposed. But they include glitches such as a non-optimal delivery route, data loss when hosts move another network, therefore they have some insecure problems about multicast data transmission. In this paper, we consider these problems and propose a new reliable and efficient multicast routing protocol for Mobile If networks. The proposed protocol provides reliable multicast transmission by compensating data loss from the previous agent when a mobile host moves another network. Also it provides additional function that is directly to connect a multicast tree according to the status of agents. It provides more efficient and optimal multicast path. The performance of the proposed protocol is proved by simulation of various conditions.

• Journal of the Korea Furniture Society
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• v.19 no.4
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• pp.273-282
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• 2008

Increasing demand for timber and the depletion of natural forest have encouraged utilization of many non-popular species. The understanding of wood properties and behavior is important to evaluate the potential of these species to produce high quality end products. This study determines the anatomical and physical properties of Hevea species viz Hevea pauciflora, Hevea guianensis, Hevea spruceana, Hevea benthamiana and Hevea brasiliensis. Each sample tree was cut into three different portions along the height (bottom- B, middle- M and upper -T parts) and two radial samples (outer- O and inner- I parts). H. brasiliensis clone RRIM 912 exhibited the longest fibre with $1214{\mu}m$, followed by H. benthamiana (HB, $1200{\mu}m$), H. pauciflora (HP, $1189{\mu}m$), H. spruceana (HS, $1158{\mu}m$) and H. guianensis (HG, $1145{\mu}m$). Fibre length has a positive correlation with specific gravity. The largest fibre diameter ($24.9{\mu}m$) and lumen diameter ($12.5{\mu}m$) were recorded in H. guianensis. The highest moisture content was obtained from H. spruceana (64.34%) compared to the lowest with 60.01% (Clone RRIM912). The higher moisture content is normally associated with lower strength. Overall, the properties of clone RRIM 912 is found to be comparatively better because of higher strength due to longer fibre length, thicker cell walls and higher specific gravity than the other Hevea species. Therefore, this species can be used as a general utility timber.

• Journal of Computing Science and Engineering
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• v.1 no.2
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• pp.177-194
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• 2007

Index selection is one of the most important decisions to take in the physical design of relational data warehouses. Indices reduce significantly the cost of processing complex OLAP queries, but require storage cost and induce maintenance overhead. Two main types of indices are available: mono-attribute indices (e.g., B-tree, bitmap, hash, etc.) and multi-attribute indices (join indices, bitmap join indices). To optimize star join queries characterized by joins between a large fact table and multiple dimension tables and selections on dimension tables, bitmap join indices are well adapted. They require less storage cost due to their binary representation. However, selecting these indices is a difficult task due to the exponential number of candidate attributes to be indexed. Most of approaches for index selection follow two main steps: (1) pruning the search space (i.e., reducing the number of candidate attributes) and (2) selecting indices using the pruned search space. In this paper, we first propose a data mining driven approach to prune the search space of bitmap join index selection problem. As opposed to an existing our technique that only uses frequency of attributes in queries as a pruning metric, our technique uses not only frequencies, but also other parameters such as the size of dimension tables involved in the indexing process, size of each dimension tuple, and page size on disk. We then define a greedy algorithm to select bitmap join indices that minimize processing cost and verify storage constraint. Finally, in order to evaluate the efficiency of our approach, we compare it with some existing techniques.

• Korean Journal of Veterinary Service
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• v.39 no.4
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• pp.259-266
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• 2016

Porcine epidemic diarrhea virus (PEDV) causes an acute and lethal watery diarrhea in piglets that is great economic losses to the swine country worldwide. The spike (S) glycoprotein is an important determinant for PEDV biological properties. In the present study, we determined the full-length S gene sequences of five Chung-nam PEDV field isolates collected in 2016. The S gene was amplified by RT-PCR, purificated, sequenced, analyzed and then compared with published sequences of other PEDV strains. 5 field strains share 98.5%~99.9% homologies with each other at the nucleotide sequence level and 96.7%~99.9% homologies with each other at the amino acids sequence level. Most field strains have nucleotide insertions, deletions and mutation regions, and show lower homologies (93.1~93.8%) with classical and vaccine strains, however higher homologies (99.1%~99.5%) with US PEDV isolates in 2013. By phylogenetic tree analysis based on nucleotide sequence, five PEDV field isolates were clustered into Genogroup 2b but differ genetically from the vaccine strains (SM-98 and DR-13).