• The Korean Journal of Ecology
• /
• v.16 no.1
• /
• pp.75-91
• /
• 1993

Structure and dynamics of Abies koreana community in Mt. Gaya were studied to provide the basic data for conservation of Abies koreana community, an endemic species in Korea. A. koreana community of this study site was composed of tree layer (4~7m), subtree layer (2~4m), shrub layer (1~2m), and herb layer (below 1m). The heights of tree and subtree layers were low. Floristic composition showed that this study site was subalpine and dry site. In frequency distribution diagram of diameter classes of major species consisting of A. koreana community, those of both A. koreana and other species showed reverse J-shaped types. From these results, it was estimated that A. koreana community of this site might be maintained continuously as a stable climax state like present state. In the spatal distribution diagram of major species, saplings of A. koreana were established under the canopy of A. koreana and Pinus koraiensis and under the dead tree of A. koreana. From these results, it was known that A. koreana saplings were recruited before the community was disturbed and regeneration was accomplished by advance regeneration pattern, in which these saplings established before occurrence of disturbance fill with open site originated from death of mature tree. Growth of annual rings was variable among individuals, it was estimated that such variation was originated in that growth of each individual relates to microclimatic conditions rather than macroclimatic ones. Ecological longevity of A. koreana in this study site estimated by disturbance types and age of dead trees was about 120 years.

• The Journal of Information Technology and Database
• /
• v.7 no.2
• /
• pp.17-32
• /
• 2000

As XML emerging as the Internet electronic document language standard of the next generation, the number of XML documents which contain vast amount of Information is increasing substantially through the transformation of existing documents to XML documents or the appearance of new XML documents. Consequently, XML document retrieval system becomes extremely essential for searching through a large quantity of XML documents that are storied in and managed by DBMS. In this paper we describe the design and implementation of BADA-IV/XML query processor that supports content-based, structure-based and attribute-based retrieval. We design XML query language based upon XQL (XML Query Language) of W3C and tightly-coupled with OQL (a query language for object-oriented database). XML document is stored and maintained in BADA-IV, which is an object-oriented database management system developed by ETRI (Electronics and Telecommunications Research Institute) The storage data model is based on DOM (Document Object Model), therefore the retrieval of XML documents is executed basically using DOM tree traversal. We improve the search performance using Node ID which represents node's hierarchy information in an XML document. Assuming that DOW tree is a complete k-ary tree, we show that Node ID technique is superior to DOM tree traversal from the viewpoint of node fetch counts.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.4
• /
• pp.613-624
• /
• 2003

This paper proposes a design for efficient and accurate retrieval of similar image subsequences using the multi-dimensional time warping distance as similarity evaluation tool in image sequence database after building of two indexing structures implemented with priority queue and suffix tree respectively. Receiving query image sequence, at first step, the proposed method searches the candidate set of similar image subsequences in priory queue index structure. If it can not get satisfied results, it retrieves another candidate set in suffix tree index structure at second step. The using of the low-bound distance function can remove the dissimilar subsequence without false dismissals during similarity evaluating process between query image sequence and stored sequences in two index structures.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.2S
• /
• pp.678-691
• /
• 2000

A variety of multimedia applications require multimedia database management systems to manage multimedia data, such as text, image, and video, as well as t support content-based image or video retrieval. In this paper we design and implement a content-based image retrieval system, BADA-IV/I$^2$R(Image Information Retrieval), which is developed based on BADA-IV multimedia database management system. In this system image databases can be efficiently constructed and retrieved with the visual features, such as color, shape, and texture, of image. we extend SQL statements to define image query based on both annotations and visual features of image together. A high-dimensional index structure, called CIR-tree, is also employed in the system to provide an efficient access method to image databases. We show that BADA-IV/I$^2$R provides a flexible way to define query for image retrieval and retrieves image data fast and effectively: the effectiveness and performance of image retrieval are shown by BEP(Bull's Eye Performance) that is used to measure the retrieval effectiveness in MPEG-7 and comparing the performance of CIR-tree with those of X-tree and TV-tree, respectively.

• The KIPS Transactions:PartD
• /
• v.9D no.4
• /
• pp.543-554
• /
• 2002

GIS (Geographic Information Systems) need faster access and better visualization. For faster access and better visualization in GIS, map generalization and levels of detail are needed. Existing spatial indexing methods do not support map generalization. Also, a few existing spatial indexing methods supporting map generalization do not support ail map generalization operations. We propose a new index structure, i.e. the LR-tree, supporting ail map generalization operations. This paper presents algorithms for the searching and updating the LR-tree and the results of performance evaluation. Our index structure works better than other spatial indexing methods for map generalization.

• Journal of Korean Society of Forest Science
• /
• v.96 no.5
• /
• pp.572-579
• /
• 2007

Tree species diversity is an important aspect of forest ecosystem stability. Tree species inventories at defined sites and in minimum diameter classes give a reliable indicator of the diversity level as well as the structural stability level of a study site. This study was conducted to investigate the species composition and the stand structure of the natural forest, timber-harvested forest (logged-over forest) and degraded forest of the Oak-twin Township in the Bago Yoma Region of Myanmar. Natural forest showed the highest family and species richness in all the investigated forests. At the family level, Verbenaceae occupied the highest importance value index (IVI) in all the forest stands while teak (Tectona grandis Linn. f.) occupied the highest IVI at the species level. However, the small diameter classes of T. grandis and other commercial species were less than those of big diameter classes in all the investigated forests. This abnormal pattern of diameter distribution could be a problem for the sustainable production of commercial timber species in the near future.

• Journal of Korea Multimedia Society
• /
• v.11 no.10
• /
• pp.1420-1426
• /
• 2008

The most recent programs tend to use picture or audio files which need mass storage resources. For these mass storages, the performance of automatic management decreases as the sizes of these resources increases. Moreover, the more the number of resources increases, the more the management of resources gets difficult. This paper suggests a resource management system to which the interface of tree-structure file system is applied in order to increase convenience and efficiency. The system uses the access technique based on character string path to have more compatibility, and supports tree structure which is more systematic. Further, it supports virtual nodes to show high performance. The system can be used to control resources from outside as well as inside of processes.

• Journal of Korea Game Society
• /
• v.11 no.2
• /
• pp.39-44
• /
• 2011

Computer games need game formulas which express game rules by mathematical functions because the game rules are automatically processed by computers. The game formulas are usually multi-variable functions. So the design of a game formula is a complex and difficult problem because it is the same problem of the design of a multi-variable function which should satisfy the related game rules. In this paper we propose a new method which can systematically design game formulas. The purposed method is the decomposing of tree structure for a game formula by analyzing the tree structure of the operands which have single-variable functions on the lowest levels. So the design method can change the complex and difficult problem of the design of a multi-variable function to the simple and easy problem of the design of the single-variable function which should satisfy the related game rules.

• Journal of Ecology and Environment
• /
• v.29 no.1
• /
• pp.17-22
• /
• 2006

Since the demands not only for value-added timber but the environmental functions of forests had been increased, native tree species has been, and is rapidly being replaced by foreign tree species in many parts of the world. However, the studies on population structure and regeneration characteristics of native tree species were not conducted enough. Regeneration of Kalopanax septemlobus growing among other hardwoods in natural forests is very difficult because of its low seed viability and germination rate. The study examined the distribution of mature trees of K. septemlobus and their regeneration pattern at the 1.12 ha study plot in natural deciduous broad-leaved forest of Mt. Jeombong. The density and mean DBH of K. septemlobus was 97 trees per ha and 32 cm, respectively. The spatial distribution of K. septemlobus showed a random pattern (aggregation index is 0.935) in the 1.12 ha study plot. The age of 90 trees among 99 sample trees of K. septemlobus ranged from 90 to 110 years and represented a single cohort, thus suggesting that K. septemlobus in advance regeneration has regenerated as a result of disturbances such as canopy opening.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.2
• /
• pp.382-388
• /
• 2011

This paper proposes a mechanism that guarantees secured performance against DDoS attack to protect data from free-roaming agent. Also, as it makes up QCRT(query chain relationship tree) structure which is an enhanced chain relation of existing chain relations that improves extension, It also finds malicious elements. The proposed mechanism extends chain relationship of agent as well by checking chain relation structure as a structure according to the route of agent. For it complements existing weakness with single-side chain relation extension, it guarantees secure performance against DDoS and truncation attacks from mobile agent.