• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.471-479
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• 2009

In this paper, we proposed an improved ray tracing method with an amelioration of visible tree structure, a visible face determination method, and non-uniform random test point method. In a proposed visible tree structure, it reduces tree nodes by means of merging similar nodes. In a visible face determination method, it shows that a ray hit test with a packet ray method can reduce a test time. A ray tracing method involving with a packet ray hit test method can improve a tree construction time up to 3.3 times than a ray tracing method with a single ray hit test method. Furthermore, by seeding a non-uniform and random test point on a face, tree construction time is improved up to 1.11 times. Received powers from the proposed ray tracing results and measured results have good agreement with 1.9 dB RMS error.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.34-37
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• 2002

Two experiments were conducted to evaluate the nutritional value of common fodder tree leaves with goats fed at 50% of total ration. In experiment 1, leaves from six fodder tree species i.e., Ailanthus aitissima, Elaeagnus angustifolic, Morus alba (Mulberry), Populus spp, Robina pseudoacacia and Salix babylonia were harvested in spring and winter from northern areas of Pakistan. Chemical composition and apparent in situ dry matter digestibility (DMD) of fodder tree leaves were measured. Results showed that crude protein (CP) values were higher (p<0.05) in all the species during spring compared to winter (17.9% vs 12.0%). The concentration of NDF in Elaeagnus and Robinia was higher in spring, whereas no seasonal difference was found in other species. In situ DMD was higher (p<0.05) in Ailanthus and Populus at spring while it was higher (p<0.05) in Elaeagnus, Mulberry and Robinia at winter. There was no (p<0.05) seasonal effect on in situ DMD of Salix. In experiment II, four iso-nitrogenous and iso-caloric rations viz., A, B, C and D were prepared containing 50% (winter harvested) sun dried leaves of Salix, Robinia, Mulberry and Elaeagnus, respectively and 50% concentrate. Dry matter and crude protein intakes were higher (p<0.05) given ration A (Salix) whereas DM and CP digestibility was lowest (p<0.05) given ration B. Nitrogen retention was higher (p<0.05) given ration A. Goats fed on fodder tree leaves and concentrate showed moderate intake and digestibility.

• Journal of Forest and Environmental Science
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• v.34 no.4
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• pp.338-351
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• 2018

This study was conducted in a long-term experimental forest in the central hardwoods region of southwestern Michigan to retrospectively examine the role of past forest management practices and climate on red oak (Quercus rubra L.) productivity. Initially, in 1971, plots within the experimental forest were treated separately with a clearcut and shelterwood regeneration harvest in an attempt to increase red oak regeneration. From 1987-1989, a new study was initiated within a portion of the clearcut and shelterwood plots to evaluate the effectiveness of additional oak crop tree release using mechanical and chemical applications. Cumulative diameter and mortality rates of 719 red oaks were monitored across the four silvicultural treatments: Clearcut-A (clearcut without additional release treatment), Clearcut-B (clearcut with additional release treatment), Shelterwood-A (shelterwood without additional release), and Shelterwood-B (shelterwood with additional release) plus an untreated control. Increment cores were obtained from red oak trees and neighboring competitor species. Tree-ring analyses (dendrochronology) were applied to examine the effect of these silvicultural treatments and climatic factors (temperature and precipitation) on red oak productivity. The results indicated that crop tree release following a clearcut or shelterwood harvest reduced mortality rates and thus increased survival of red oak. Red oak in control plots or plots only receiving the initial regeneration harvesting treatment and no additional competition release were negatively affected by climatic stress, which included summer moisture stress. In contrast, red oak in plots that received the competition release treatment from shade tolerant tree species not only had higher tree level productivity (i.e., tree basal area) and lower mortality rates, but were also relatively more resilient to climatic stress by showing limited or no associations between climate and growth.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.19-25
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• 2010

In this paper, digital watermarking method using quad-tree algorithm is proposed. The proposed algorithm searches the significant coefficient of the watermark by using quad-tree algorithm and inserts the watermark by the Cox's algorithm. The simulation for performance analysis of the proposed algorithm is implemented about the effect of quad-tree algorithm in wavelet domain and that of embedding watermark in each subband coefficient (HH, LH, HL) and each DWT level, and that of embedding in the lowest frequency band (LL). As a simulation result, digital watermarking using quad-tree algorithm improves the watermarking performance in comparison with inserting watermark in the significant coefficients of fixed frequency band. The watermarking performance of simultaneously embedding in HH, LH, and HL band of DWT(6 level) is better than that of different cases. In addition, insertion the watermark to the LL band about 30~60% of all watermarks improves the correlation value while PSNR performance decreases 1~3dB.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4B
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• pp.323-332
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• 2011

In order to properly manage trees in rivers, the impact of trees on flooding and their ecological characteristics need to be considered and a plan needs to be established. The hydraulic impact by trees is reduction of conveyance and hydraulic structure's function due to overturn arising from flow force. A field pulling test was carried out to measure the critical resistance force for when trees break in order to discover the level of resistance that trees inside the river have to external force. The relevant factors for discovering the critical breaking moment for trees include tree species, which determines the external characteristic of trees, tree diameter at breast height, and tree height. In this study, the correlation between critical breaking moment and diameter at breast height were used. The tree's limit or critical breaking moment was tested using 100 shrubs and tall trees with a breast height diameter of 4.9 to 32.8 cm. It was difficult to derive a correlation between diameter at breast height and critical breaking moment when shrubs and tall trees were being considered together, but when only tall trees were considered, a consistent correlation was found between them.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.435-445
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• 2013

One of the most challenging issues in radio frequency identification (RFID) and near field communications (NFC) is to correctly and quickly recognize a number of tag IDs in the reader's field. Unlike the probabilistic anti-collision schemes, a query tree based protocol guarantees to identify all the tags, where the distribution of tag IDs is assumed to be uniform. However, in real implements, the prefix of tag ID is uniquely assigned by the EPCglobal and the remaining part is sequentially given by a company or manufacturer. In this paper, we propose an enhanced M-ary query tree protocol (EMQT), which effectively reduces unnecessary query-response cycles between similar tag IDs using m-bit arbitration and tag expectation. The theoretical analysis and simulation results show that the EMQT significantly outperforms other schemes in terms of identification time, identification efficiency and communications overhead.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.758-762
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• 2008

Embedded systems usually utilize Flash Memories with very nice characteristics of non-volatility, low access time, low power and so on. For the multimedia database systems, R-tree is an indexing tree with nice characteristics for multimedia access. MR-tree, which is an upgraded version of R-tree, has shown better performance in searching, inserting and deleting operations than R-tree. Flash memory has sectors and blocks as a unit of read, write and delete operations. Especially, the delete is done on a unit of 512 byte blocks with very large operation time and it is also known that read and write operations on a unit of block matches caching nature of MT-tree. Our research optimizes MR-tree operations in a unit of Flash memory blocks. Such an adjusting leads in better indexing performance in database accesses. With MR-tree on a 512B block units we achieved fast search time of database indexing with low height of MR-tree as well as faster update time of database indexing with the best fit of flash memory blocks. Thus MR-tree with optimized operations shows good characteristics to be a database index schemes on any systems with flash memory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1475-1482
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• 2009

In ZigBee network, using energy efficiently is necessary because ZigBee node works by battery. To use energy efficiently, it is one of the way to reduce unnecessary network traffic. In this paper, it presents efficient shortcut routing algorithm using depth of destination node in ZigBee network. In traditional tree routing, each node transfers data only to its own parent or child node, which is inefficient way. Efficient shortcut routing algorithm is also based on tree routing. However, we suggests the algorithm with using neighbor table and depth of destination that is able to transfer data to other neighbor node, not only to parent or child node. It minimizes coordinator bottleneck state and unnecessary intermediate routing path which happens in traditional tree routing.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.421-428
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• 2020

Tamarind (Tamarindus indica L.) is one of the multipurpose tree species distributed in the tropical and sub-tropical climates. It is an important fruit yielding tree that supports the livelihood and has high social and cultural values for rural communities. The vegetative, reproductive, qualitative, and quantitative traits of tamarind vary widely. Characterization of phenotypic and genetic structure is essential for the selection of suitable accessions for sustainable cultivation and conservation. This study aimedto examine the genetic relationship among the collected accessions of sweet, red, and sour tamarind by using Random Amplified Polymorphic DNA (RAPD) primers. Nine accessions were collected from germplasm gene banks and subjected to marker analysis. Fifteen highly polymorphic primers generated a total of 169 fragments, out of which 138 bands were polymorphic. The polymorphic information content of RAPD markers varied from 0.10 to 0.44, and the Jaccard's similarity coefficient values ranged from 0.37 to 0.70. The genetic clustering showed a sizable genetic variation in the tamarind accessions at the molecular level. The molecular and biochemical variations in the selected accessions are very important for developing varieties with high sugar, anthocyanin, and acidity traits in the ongoing tamarind improvement program.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.1
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• pp.18-23
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• 2003

This study was conducted to compare physiological responses of Pinus densiflora, Populus ${\times}$ tomentiglandulosa, Quercus acutissima and Eleutherococcus sessiliflorus exposed to SO$_2$, by measuring photosynthetic pigment contents and SOD activity. Four woody plants were exposed to relatively high SO$_2$ concentration (500 ppb, 800 ppb) for 8h day$^{-1}$ for 7 days in a chamber. Photosynthetic pigment contents in the leaves of four species decreased with increase of SO$_2$ concentration; also chlorophyll a, chlorophyll b and total carotenoid content were significantly different among tree species and treatments. The ratio of chlorophyll b to chlorophyll a of E. sessiliflorus and Q. acutissima increased for 500 ppb treatment but decreased at 800 ppb. This result showed that chlorophyll a was destroyed by 500 ppb SO$_2$ and chlorophyll b by 800 ppb SO$_2$. Therefore, the sensitivity of chlorophyll a to SO$_2$ may be higher than that of chlorophyll b. SOD activity differed significantly between species and treatments. SOD activity of E. sessiliflorus and Q. acutissima increased at 500 ppb but decreased at 800 ppb, but P. densiflora and P ${\times}$tomentiglandulosa maintained high SOD activity at both 500 ppb and 800 ppb. Based on the photosynthetic pigment contents and SOD activity in the leaves of four tree species, the tolerance of P. ${\times}$ tomentiglandulosa to SO$_2$ was the highest of four tree species.