• Journal of Environmental Science International
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• v.7 no.6
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• pp.745-751
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• 1998

The well-mixed room model has been traditionally used to predict the concentrations of contaminants in indoor environments. However, this is inappropriate because the flow fields in many indoor environments distribute contaminants non-uniformly, due to imperfect air mixing. Thus, some means used to describe an imperfectly mixed room are needed. The simplest model that accounts for imperfect air mixing is a two-zone model. Therefore, this study on development of computer program far the two-zone model is carried out to propose techniques of estimating the concentration of contaminants in the room. To do this, an important consideration is to divide a room into two-zone, i.e. the lower and upper zone assuming that the air and contaminants are well mixed within each zone. And between the zones the air recirculation is characterized through the air exchange parameter. By this basic assumption, the equations for the conservation of mass are derived for each zone. These equations are solved by using the computational technique. The language used to develope the program is a VISUAL BASIC. The value of air exchange coefficient($f_12$) is the most difficult to forecast when the concentrations of contaminants in an imperfectly mixed room are estimated by the two-zone model. But, as the value of $f_12$ increases, the air exchange between each zone increases. When the value of $f_12$ is approximately 15, the concentrations in both zone approach each other, and the entire room may be approximately treated as a single well-mixed room. Therefore, this study is available for designing of the ventilation to improve the air quality of indoor environments. Also, the two-zone model produces the theoretical base which may be extended to the theory for the multi-zone model, that will be contributed to estimate the air pollution in large enclosures, such as shopping malls, atria buildings, atria terminals, and covered sports stadia.

• Journal of Korean Society of Rural Planning
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• v.22 no.1
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• pp.25-35
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• 2016

This study targets Korean culture theme park in Yeongju-Zone and World confucian scholar culture park in Bonghwa-Zone among the Three Major Cultural Areas Projects supervised by Ministry of Culture, Sports and Tourism. The study analyzes the Historical and Cultural Authenticity of each project on the basis of the reports and the report materials for meeting with related organizations. The results of the study are drawn as follows. First, through the theoretical consideration, this study drew the types of authenticity: originality, identity, specificity and visibility, which are evaluation items on the Historical and Cultural Authenticity. Second, Bonghwa-Zone succeeded in acquiring originality with tangible cultural properties but Yeongju-Zone chose a project site without it. Third, with originality, Bonghwa-zone was evaluated as having resources and concept with high traditional culture connectivity and fulfilled identity. It led the feature showing the high affinity between originality and identity. Fourth, compared to the projects of Andong-Zone in the Three Major Cultural Areas Projects, these two projects failed to acquire the distinctions since the primary and the secondary influence area and major facilities & programs coincided with those of the projects of Andong-Zone. Fifth, compared to Bonghwa-Zone, Yeongju-Zone realized visibility faithfully by the conceptual flexibility of "Korean Culture" and a large-scale development. Sixth, in terms of the Historical and Cultural Authenticity of project plan, it is evaluated that Yeongju-Zone and Bonghwa-Zone only fulfilled visibility and specificity respectively.

• Journal of KIISE:Information Networking
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• v.33 no.4
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• pp.299-309
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• 2006

In Mobile ad hoc networks, AODV is one of the famous on-demand routing protocol, which use the routing tables in the nodes if possible, or Route Discovery Process (RDP) is triggered to find a new route. However increasing the traffic of RDP causes dropping of the network performance in the large size of ad hoc networks. In this paper, we propose a novel routing protocol, named as AOZDV (Ad hoc On-demand Zone and Distance-Vector Routing), which enhances the AODV protocol with zone routing. AOZDV creates a Zone with neighbor nodes of the source/destination using traffic and power information, and utilizes Destination-Vector Table for internal routing in the Zone. We show by simulations that AOZDV can reduce the occurrence rate of route fail and RDP caused by route fail compared to existing routing protocols such as DSR and AODV.

• Journal of Ecology and Environment
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• v.37 no.4
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• pp.185-194
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• 2014

Seasonal monitoring was implemented to understand the influence of macrophyte bed structure on the composition and trophic interaction of aquatic organisms (algae, zooplankton, macro-invertebrate, and fish) in a shallow wetland (Upo Wetland, South Korea). Distinct division of the plant assemblage (reed zone and mixed plant zone) was observed. The reed zone was composed solely of Phragmites communis, whereas the mixed plant zone comprised a diverse macrophyte assemblage (Salvinia natans, Spirodela polyrhiza, Trapa japonica, Ceratophyllum demersum, and Hydrilla verticillata). Most of the aquatic organisms were more abundant in the mixed plant zone than in the reed zone, and this was positively associated with the seasonal development of macrophyte cover. Stable isotope analysis showed seasonal interactions among aquatic organisms. The majority of aquatic animal (zooplankton, Odonata, and Ephemeroptera) were dependent on epiphytic particulate organic matter (EPOM), and the dependence on EPOM gradually increased toward autumn. Interestingly, Lepomis macrochirus consumed Ephemeroptera and zooplankton in both macrophyte zones, but Micropterus salmoides depended on different food items in the reed zone and the mixed plant zone. Although, M. salmoides in the reed zone showed food utilization similar to L. macrochirus, it consumed Odonata or small L. macrochirus in the mixed plant zone. Based on these results, it appears that differences in the structure of the two macrophyte zones support different assemblages of aquatic organisms, strongly influencing the trophic interactions between the aquatic organisms.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.561-567
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• 2009

The distribution of benthic macroinvertebrates of Shinbulsan wetland was investigated. This study was focused on the degree of recovery of habitat by comparing the community structure of benthic macro invertebrates of zone D to that of zone A, intact habitat. The zone D was destructed due to the construction of a golf club and the survey was performed in zone A and zone D of Shinbulsan wetland. The seasonal survey was performed in April, July and September from 2006 to 2007. From the sampling, 2 phyla, 3 classes, 9 orders, 31 families, 69 species and 1155 individuals of benthic macroinvertebrates were collected. From zone A, 2 phyla, 3 classes, 9 orders, 23 families, 54 species and 678 individuals were identified. From zone D, 2 phyla, 3 classes, 9 orders, 23 families, 43 species and 477 individuals were identified. Species diversity and species richness were higher in zone A than in zone D. The recovery of zone D was inefficient as humidity of soil was not enough to live macroinvertebrates. Also, an endangered species of macroinvertebrates, Nannophya pygmaea was found during this investigation.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.340-345
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• 2006

A potato (Solanum tuberosum L. cv. Superior) cultivar was grown in aeroponic cultivation system to investigate the effect of root zone cooling in summer. Based on their nutrient uptake, growth responses, and tuberization, the possibilities for potato seed production were determined. Although shoot growth and early tuberization increased in the conventional non-cooling root zone system (root zone temperature of $25\pm2^{\circ}C$), stolen growth, photosynthesis, transpiration rate and number of tubers produced were higher in the cooling root zone system ($20\pm2^{\circ}C$) than in the non-cooling system. Increasing root zone temperature above $25^{\circ}C$ stimulated absorption of K more than T-N, P, Ca, Fe and Mn. On the other hand, root zone temperatures in the range of $20^{\circ}C$ to $25^{\circ}C$ did not affect Mg contents. The lower uptake and supply to leaves of T-N, Fe and Mn at the high root zone temperature promoted early tuberization and advanced haulm senescence. The results stress the importance of keeping root zone temperature to as low as below 20, particularly in summer under temperate Bone.

• Journal of Welding and Joining
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• v.20 no.5
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• pp.87-92
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• 2002

Weldability of Friction Stir Welded(FSW) AZ31B-H24 Mg alloy sheet with 4m thick was evaluated by changing welding speed. The sound welding conditions mainly depended on the suffiicient welding heat input during the process. The insufficient heat input resulted in the void like defect in the weld zone. Higher welding speed caused a larger inner void or lack of bonding. The defects were distributed at the stir zone or the transition region between stir zone and thermo-mechanical affected zone (UE). The size of defects slightly increased with increasing welding speed. These defects had a great effect on the joint strength of weld zone. The weld zone was composed of stir zone, TMAZ and heat affected zone. The stir zone was cosisted of fine recrystallized structure with $5-8\mu\textrm{m}$ in the mean grain size. The hardness of weld zone was near the 60HV, which was slightly lower than that of base metal. The maximum joint strength was about 219MPa that was 75% of that of base metal and the yield strength was also lower than that of base metal partly due to the existance of defects.

• Journal of Powder Materials
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• v.25 no.4
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• pp.331-335
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• 2018

This study investigates the directional recrystallization behavior of Ni based oxide dispersion strengthened (ODS) alloy according to the zone annealing velocity. The zone annealing temperature is set as $1390^{\circ}C$, while the zone velocities are set as 2.5, 4, 6, and 10 cm/h, respectively. The initial microstructure observation of the as-extruded sample shows equiaxed grains of random orientation, with an average grain size of 530 nm. On the other hand, the zone annealed samples show a large deviation in grain size depending on the zone velocities. In particular, grains with a size of several millimeters are observed at 2.5-cm/h zone velocity. It is also found that the preferred orientation varies with the zone annealing velocity. On the basis of these results, this study discusses the role of zone velocities in the directional recrystallization of Ni base ODS alloy.

• Journal of KIISE
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• v.42 no.5
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• pp.551-557
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• 2015

The technology using ARM TrustZone draws attention as a new embedded virtualization approach. The ARM TrustZone defines two virtual execution environment, the secure world and the normal world. In such an environment, the inter-world communication is important to extend function of software. However, the current monitor software does not sufficiently support the inter-world communication. This paper presents a new inter guestOS communication scheme, for each world, for the ARM TrustZone virtualization. The proposed communication scheme supports bidirectional inter-world communication for single core and multicore environment. In this paper, It is implemented on a NVIDIA Tegra3 processor based on the ARM Cortex-A9 MPCore and it showed a bandwidth of 30MB/s.

• Water for future
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• v.22 no.3
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• pp.289-298
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• 1989

A review is made of transient phenomena ralation to flow in the vadose zone. Reviewed topics include rapid water table response to rainfall, pulsating flow due to pressure perturbations in the vasoes zone, and the wave-like propagation of increased soil moisture caused by intermittent rainfall. As a basis of interpreting these phenomena, zoning of the vadose zone into a residual water zone, an unsaturated capillaty zone, and a saturated capillary zone are proposed. Possible implications with respect to hydrological processes relating to these phenomena are discussed.