• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.228-235
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• 2016

Nitrite accumulation is essential for constructing an anammox process. As the pH in the reactor exerts a complicated and strong influence on the reaction rate, we investigated its effects upon treatment of an ammonic wastewater (2,000 mgN/L) through modeling and experiment. The modeling results indicated that the reaction stability is strongly affected by pH, which results in a severe reduction of the 'stable region' of operation under alkaline environments. On a coordinate of the total ammonia nitrogen (TAN) concentration vs. pH, the maximal stable reaction rates and the maximal nitrite accumulation potentials could be found on the 'stability ridge' that separates the stable region from the unstable region. We achieved a stable and high ammonia oxidation rate (${\sim}6kgN/m^3-d$) with a nitrite accumulation ratio of ~99% when operated near the 'stability ridge'. The optimum pH that can be observed in experiments varies with the TAN concentrations utilized, although the intrinsic optimum pH is fixed. The direction of change is that the optimum operational pH falls as the TAN concentration increases, which is in excellent accordance with the observations in the literature. The optimum operational pH for 95% nitritation was predicted to be ~8.0, whereas it was ~7.2 for 55% partial nitritation to produce an anammox feed in our experimental conditions.

• Journal of the Korean association of regional geographers
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• v.8 no.2
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• pp.170-183
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• 2002

Recently it is supposed to be a shift to regional geography. To understand the emergence of the new regional geography, It must be remarked that the progress of capitalist production and consumption change our conceptional apparatus such as representation of space. Region is one of the important mode of representations of space and time. In the Fordist capitalism of 20th century, development is regarded as diffusion of capitalist expansion of western worlds. State must support capitalist growth through regional policies which include constructing of infrastructure and regionalization of spatial division of labour. The regional development theories contributed as ideology and policy tools for state intervention. The region was simply one of the most logical classification tools of organizing geographical informations. In the theories of regional development, the concept of region was reduced to the formal unit of classification. As the transition from Fordism to flexible accumulation, the region is again acquiring its 'identity' and 'authenticity'. In this tendency of the revival of region, it is expected that good achievement could be made in the field of regional geography through relevant research methods. It is also believed one of the available means are historical approaches to the cultural and ecological regions. The historical approaches to cultural and ecological regions are not only correspondent with cultural development strategies of local governments, but also could convey regional identities through both narrativization of place and aestheticization of landscape.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.149-156
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• 1997

This study extracts the several informations by computerizing the maps of the new city, i.e. Yang-San, MuI-Gum. This cities are being constructed by Land Coporation, and a map of province based on 1:50,000 scales were digitalized depending on topography by digitizer. Several information was taken, by computerizing a existing design maps, with digitalized maps used. Also, there is map number based on each scale, and measure a settlement of the foundation for constructing a facility in a study region, then intend to use information. This paper aims at using old data such as ancient writing books by computerization permanently.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1004-1008
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• 2003

Near-filed optical storage using cantilever aperture tip is a promising way fer next generation optical data storage. To enhance the speed of reading and writing data, gap between tip and media should be controlled fast and precisely within near field region. In this paper, several PZT actuators are analyzed far constructing dual servo control algorithm: coarse actuators(stact. PZT, bimorph PZI) for media surface inclination and One actuator(film PZT) for media surface roughness. Dynamic analysis of stack PZT, bimorph PZT, and film PZT are performed through the frequency response. Based on the frequency response and mathematical model, fast analog controller is designed.

• 한국전산유체공학회:학술대회논문집
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• 2007.04a
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• pp.17-22
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• 2007

Chimera grid Method is widely used in Computational Fluid Dynamics due to its simplicity in constructing grid system over complex bodies. Especially, Chimera grid method is suitable for unsteady flow computations with bodies in relative motions. However, interpolation procedure for ensuring continuity of solution over overlapped region fails when so-call orphan cells are present. We have adopted MLS(Moving Least Squares) method to replace commonly used linear interpolations in order to alleviate the difficulty associated with orphan cells. MSL is one of interpolation methods used in mesh-less methods. A number of examples with MLS are presented to show the validity and the accuracy of the method.

• Smart Structures and Systems
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• v.16 no.1
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• pp.27-46
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• 2015

Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.

• Journal of the Korean Home Economics Association
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• v.17 no.4
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• pp.1-14
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• 1979

The functional problems of the basic pattern of clothing are a matter of the first importance to clothing construction. Therefore, the ergonomic analysis of the expansion and contraction of the upper body surface, due to motion, has become required. thus in order to obtain the measurements and rate of expansion and contraction of the upper body surface following from its motions, the development figure of " Shell" and somatometry were employed. The results obtained through the investigation can be summarized as follows : 1) According to the developmental figures of "Shell" the latitudes centering around the shoulder line present contractive tendencies by arm movement. The longitudes around the center back waist length are expansive tendencies when bent forward. In the case of a 15$^{\circ}$ lean backward posture, the longitudes around the center front waist length are expansive tendencies. 2) By somatometry, the region from the scapula to the axilla point the upper back with presents the greatest expansion (more than 30%). The region from scapla to arm presents the maximum rate of contraction. In considering the longitude , under the axilla waist length and the bust point waist length generally shows the greatest rate of expansion. 3) The bust point waist length and under the axilla waist length are of great importance to the basic pattern of clothing. and have expansive tendencies(6.3cm). Among the latitudes, the upper back width has the greatest tendency for expansion (7.83 cm). 4) The region which presents the greatest rate of the expansion and contraction is in the proximity of the arm. These results testify that the amount of room of the back width must be given consideration in constructing the basic pattern of clothing.pattern of clothing.

• Journal of Hydrogen and New Energy
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• v.32 no.6
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• pp.551-564
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• 2021

The use of clean energy based on the hydrogen economy is increasing rapidly due to the greenhouse gas reduction policies and the increase in the need for hydrogen. Currently, South Korea government have been considering a plan to construct hydrogen refueling stations at expressway service area for the purpose of supplying hydrogen vehicles. In the case of a hydrogen refueling stations, a quantitative risk assessment (QRA) must be performed because it includs and uses a high pressurized hydrogen storage tank. In this study, QRA was conducted using societal risk and F-N curve by the consequence assessment (CA) of jet fire and explosion according to the population density, capacity of the high pressurized hydrogen storage tank and frequency assessment (FA) data to the general hydrogen refueling stations systems in expressway service area. In the cases of jet with a leak diameter of 7.16 mm, regardless of expressway service area location, the societal risk was over 1E-04 that was acceptable for as Low As reasonably practicable (ALARP) region (workforce), but unacceptable for ALARP region (public). In the cases of gas explosion, all expressway service area satisfy ALARP region. In the case of the population density is over 0.0727, QRA for constructing the hydrogen refueling stations, must be conducted.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.485-489
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• 2003

The region of Kochang(Chollabuk-Do) located in the west-southern area of the Korea and passed by the West Coast Expressway has the yellow collar soil(Hwang-To) primarily containing clay. Hwang-To serves as a soil appropriate for growing the watermelon and yam, but as a subgrade material not strong for constructing the roads. Particularly, the subgrade material of this study site was not qualified for the standard of the subgrade material quality. The properties of the subgrade layer showed that the strength of the subgrade material was not strong enough to sustain the subgrade strength in constructing the roads since the passing ratio of the No. 200 sieve was about 25％ to 82％ and the ground water level was early equal to subgrade one. Thus, the objective of this study was to present the methods obtaining the proper subgrade strength of cutting area to construct the secure and solid expressways in the fragile area.

• Geomechanics and Engineering
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• v.36 no.6
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• pp.601-618
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• 2024

The joint probability distribution of uncertain geomechanical parameters of geotechnical strata is a crucial aspect in constructing the reliability functional function for roof structures. However, due to the limited number of on-site exploration and test data samples, it is challenging to conduct a scientifically reliable analysis of roof geotechnical strata. This study proposes a Copula method based on small sample exploration and test data to construct the intensity characteristics of roof geotechnical strata. Firstly, the theory of multidimensional copula is systematically introduced, especially the construction of four-dimensional Gaussian copula. Secondly, data from measurements of 176 groups of geomechanical parameters of roof geotechnical strata in 31 coal mines in China are collected. The goodness of fit and simulation error of the four-dimensional Gaussian Copula constructed using the Pearson method, Kendall method, and Spearman methods are analyzed. Finally, the fitting effects of positive and negative correlation coefficients under different copula functions are discussed respectively. The results demonstrate that the established multidimensional Gaussian Copula joint distribution model can scientifically represent the uncertainty of geomechanical parameters in roof geotechnical strata. It provides an important theoretical basis for the study of reliability functional functions for roof structures. Different construction methods for multidimensional Gaussian Copula yield varying simulation effects. The Kendall method exhibits the best fit in constructing correlations of geotechnical parameters. For the bivariate Copula fitting ability of uncertain parameters in roof geotechnical strata, when the correlation is strong, Gaussian Copula demonstrates the best fit, and other Copula functions also show remarkable fitting ability in the region of fixed correlation parameters. The research results can offer valuable reference for the stability analysis of roof geotechnical engineering.