• Journal of Ecology and Environment
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• v.32 no.4
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• pp.267-275
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• 2009

To investigate the possible applications of plants to remediate heavy-metal-contaminated soil, a pilot experiment was performed for four years in a reclaimed dredging area using two Alnus species, i.e., Alnus firma and Alnus hirsuta. In a comparison of phytomass of the two species at two different planting densities, the phytomass of Alnus planted at low density was twice as high as that of Alnus planted at high density after four years. The Alnus species showed active acclimation to the heavy-metal-contaminated soil in a reclaimed dredging area. A. hirsuta showed greater accumulation of phytomass than A. firma, indicating that it is the better candidate for the phytoremediation of heavy-metal-contaminated soils. In the pilot system, Alnus plants took metals up from the soil in the following order; Pb > Zn > Cu > Cr > As > Cd. Uptake rates of heavy metals per individual phytomass was higher for Alnus spp. planted at low density than those planted at high density in the pilot system. Low plant density resulted in higher heavy metal uptake per plant, but the total heavy metal concentration was not different for plants planted at low and high density, suggesting that the plant density effect might not be important with regard to total uptake by plants. The quantity of leached heavy metals below ground was far in excess of that taken up by plants, indicating that an alternative measurement is required for the removal of heavy metals that have leached into ground water and deeper soil. We conclude that Alnus species are potential candidates for phytoremediation of heavy-metal- contaminated surface soil in a reclaimed dredging area.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.446-453
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• 1999

In this study, the effects of stand planting density on parameters of stand height and basal area growth models were investigated. We used the Korf equation as the base model in estimating the parameters of the growth models for cryptomeria plantation forest stands. Then, in order to investigate the effects of the change in plantation density on the parameter estimates, the "extra sums of square" principle, which provided a reasonable statistical procedure for a performance test, was used. The results of the test coincide with the understandings that stand height growth is not affected significantly by the planting density and the growth curves of stand basal area approaches a common asymptote regardless of the stand density for a given site. However, the shapes of the basal area growth curves were affected significantly by the planting density. Based on the results of the test, we developed a basal area growth model to account for the effects of initial planting density in cryptomeria plantation forest stands.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.29-32
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• 2007

Tidal channel development is influenced by sediment type, grain size, composition and tidal current. Tidal channels are usually characterized by channel development, density and shape. Quantitative analysis of tidal channels using remotely sensed data have rarely been studied. The objective of this study is to quantify tidal channels in terms of fractal dimension and compare different inter-tidal channel patterns. For the fractal analysis, we used Box counting method which had been successfully applied to streams, coastlines and others linear features. For a study, the southern part of Ganghwado tidal flats was selected where is famous for high dynamics of tidal currents and vast tidal flats. This area has different widths and lengths of tidal channels. IKONOS and Komsat-2 MSC images were used for extracting tidal channels, and the Box counting method was applied to obtain fractal dimensions (D) for each tidal channel. Yeochari area possesses channels with linear pattern and less dense development and accordingly show low D values ranging from 1.037 to 1.038. On other hands, area (near Donggumdo and Yeongjongdo ) of dendrites channel pattern and dense development resulted in high D values from 1.2057 to 1.2667. Also, area possesses channels with linear pattern had low density about $18{\sim}24%$. Area of dendritic channel pattern had high density about $34{\sim}69%$. The difference of fractal dimensions about 0.2 according to channel development in tidal flats is relatively large enough to use as an index for tidal channel classification. Also, area where channels showed linear pattern had low density about $18{\sim}24%$. Area of dendritic channel pattern had high density about $34{\sim}69%$. Using fractal dimension and density, it would be possible to quantify the tidal channel development in association with surface characteristics.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.4
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• pp.40-47
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• 2007

The objective of this study is to analyze the propriety of the Biotope Area Factor's(BAF) application and propose an improvement plan. The BAP system, initially started by Seoul metropolitan city, is being settled in Korea. The BAF originated from the Biotop $Fl{\ddot{a}}chen$ Faktor(BFF) system of Berlin Germany. It was established as part of the Landscape Plan for the ecological function recovery in the high density built-up area with a sense of environmentally friendly urban management. The study compared the BAF's present condition of Ganddong-Gu, Seoul with Seoul's BAF system. Some problems appeared from the system application. Firstly, it may cause ecological damage if the site ranges are more than current BAF system limits. Secondly, the application of the current BAF system has the possibility of general redevelopment, but the partial improvement considering current standards of the high density built-up area's paving section is impossible. Lastly, division of the application object and application type are not divided well. In addition, the Seoul BAF which is currently applied across the board is based on the destruction of the natural area and low density built-up area. Accordingly, to improve these problems requires a complementary system protecting the ecological function prior to the application of the BAF and with restricted application to high density of BAF system built-up area.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.1
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• pp.62-72
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• 1997

As a site is built up, runoff increases inevitably. This results in water deficit in the site and possible downstream flooding. It may cause irreversible site ecosystem disturbance. This study examined some techniques of increasing infiltration rates in a site development. The possible effects of applying such techniques at a new town development are calculated for four types of land uses-business area, low/high density residential areas, and park area- of Bun-Dang New Town. If the higher infiltration drainage systems are introduced, there may be additional infiltration of the precipitation as much as 59.8% in business area, 74.6% in low density residential area, 51.4% in high density residential area and 32.7% in park area. This much increase of infiltration, or decrease of runoff, may improve site water balance, and thus keep the site ecosystem much healthier.

• The Korean Journal of Ecology
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• v.20 no.5
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• pp.355-365
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• 1997

Macrozoobenthic community structure was studied on the mud-tidalflat around Mokpo coastal area, Korea, from September 1995 to May 1996. Ten sampling stations were chosen along the 1km transect with a 100 m intervals. Triple macrozoobenthos sampling were conducted with a stainless box core sampler (size $13{\times}22{\times}30$ cm) at each station on the seasonal basis. A total of 119 species of macrobenthos was sampled with a mean density 2,357 $ind./m^2$ and biomass of 180. 94 $g/m^2$ during the study period. Of these species, there were 51 species of mollusce (43%), 36 of crustaceans (30%), 27 of polychaetes (23%). Molluscs were density-dominant faunal group with a mean density of 1,804 $ind./m^2$, comprising of 75% of the total density of the benthic animals. It was followed by polychaetes with 347 $ind./m^2$ (15% of the total density). Molluscs were biomass-dominant faunal group with a mean biomass of 147.51 $g/m^2$ (82% of the total biomass). The number of species, abundance and biomass showed increasing trends toward the lower intertidal stations from the higher stations. Major dominant species were Musculista senhousia (bivalve), Capitellidae spp. (polychaetes) with a density of 1,640 $ind./m^2$ and 179 $ind./m^2$ , respectively. The density of M. senhousia was more than 63% of the total density of benthic organism on the tidal area. Small gastropod Cerithideopsilla umumriensis was another dominant epifaunal species between st.1 and 2 with a mean density of 100 $ind./m^2$. Cluster analysis showed that the benthic community could be divided into three stational groups, that is, upper, middle and lower groups by the exposure duration.

• Journal of Plant Biology
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• v.15 no.2
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• pp.7-19
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• 1972

The studies of density effect or the effect of population density on plant growth have been done on basis of dry matter production with Raphanus acanthiformis var. simoodaeguen, Brassica campestris var. Pekinensis f. namsounsokoombecheu, Oryza sativa f. kimmajae and O. sativa f. mangyeng grown in the various spacing. 1. In the early period of plant growth in dry weight was not different each other among varying densities, but as time advanced the plant grown vast space grew sufficiently compared with those of narrow one. 2. Iogarithmic relation between the growth of plant (W) and the density (P), log W-log P in the material plants, were approximated by two straight lines, one was horizontal line and another inclined: the former showed non-competition density and the latter competition density addition to these the point interlinking both lines were implied of the optimum density per unit land area at certain growth period. 3. The values of relatvie growth rate (RGR) and net assimilation rate (NAR) were decreased as increase in the density, while those of leaf area ratio (LAR) were rather increased in the same condition, with minor exception. From these results and relation between the productive structure and due to lack of the recieved light intensity owing to the mutal shading among the plants.

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.58-64
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• 2000

Assuming that the performance of holographic storage media is ideal, we estimate the area storage density of disk-type holographic memories, when the method of either angle multiplexing, or rotational multiplexing, or both are used. The area storage density is strongly dependent on the f numbers (ratio of focal length to diameter) of both the Fourier transform lens in the signal arm, denoted by $F/#_2$, and the angle range over which the reference beam is incident (or, the equivalent f number corresponding to the angle range denoted by $F/#_1$). The area storage density is largely independent of the pixel pitch of the spatial light modulator when the Fourier plane holograms are recorded, while it is sensitive to the pixel pitch when the image plane holograms are recorded. In general, to obtain high area storage density, the Fourier or at least near Fourier plane holograms rather than the image plane holograms should be recorded. In addition, when the thickness of the recording materials are less than approximately $500\mu\extrm{m}$, rotational multiplexing gives higher area storage densities than angle multiplexing does. To increase the storage density further, however, it is desirable to use both of the two multiplexing methods in combination.nation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2170-2190
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• 2012

There are nowadays strong demands for intelligent surveillance systems, which can infer or understand more complex behavior. The application of crowd density estimation methods could lead to a better understanding of crowd behavior, improved design of the built environment, and increased pedestrian safety. In this paper, we propose a new crowd density estimation method, which aims at estimating not only a moving crowd, but also a stationary crowd, using images captured from surveillance cameras situated in various public locations. The crowd density of the moving people is measured, based on the moving area during a specified time period. The moving area is defined as the area where the magnitude of the accumulated optical flow exceeds a predefined threshold. In contrast, the stationary crowd density is estimated from the coarseness of textures, under the assumption that each person can be regarded as a textural unit. A multilayer neural network is designed, to classify crowd density levels into 5 classes. Finally, the proposed method is experimented with PETS 2009 and the platform of Gangnam subway station image sequences.

• Transactions of Materials Processing
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• v.31 no.5
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• pp.281-289
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• 2022

Presently, 3D printers manufactured by material extrusion are economical and easy to use, so they are being used in various fields. However, this study conducted a tensile test on the infill pattern and density of the PLA+ material, due to the limitations of long printing time as well as low mechanical strength. The infill area for the infill density change was measured, using a vision-measuring machine for four infill patterns (concentric, zigzag, honeycomb, and cross) in which the nozzle path was the same for each layer. The tensile strength/weight[MPa/g] and tensile strength/printing time[MPa/min] of the tensile specimens were analyzed. In this study, efficient infill density and patterns are suggested, for cost reduction and productivity improvement. Consequently, it was confirmed that the infill area and infill percentage of the four patterns, were not constant according to the infill pattern. And the tensile strength of the infill density 40% of the honeycomb pattern and infill density 20% of the cross pattern, tended to highly consider the weight and printing time. Honeycomb and cross patterns could reduce the weight of the tensile specimen by 19.11%, 28.07%, as well as the printing time by 29.56%, 52.25%. Tensile strength was high in the order of concentric, zigzag, honeycomb, and cross patterns, considering the weight and printing time.