• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.277-281
• /
• 2011

In this study, past method and recent method for flood discharge with domestic multi-purpose dams in Korea were compared and analyzed with respect to the scale of watershed. Rainfall depth, temporal distribution, effective rainfall, rainfall-runoff model, parameter estimation and base flow were selected as the principal factors affecting flood discharge and effects on flood discharge were analyzed quantitatively by using sensitivity analysis. The results showed that the flood discharges calculated by past and recent method increased and decreased with a wide range of discharge with respect to the scale of watershed. The reason for decrease of flood discharge is the exchange of temporal distribution pattern of rainfall and the principal reason for increase of flood discharge are the increase of rainfall depth by unusual weather phenomena and the difference of estimation method of parameters of unit hydrograph.

• Korean Chemical Engineering Research
• /
• v.58 no.2
• /
• pp.176-183
• /
• 2020

In this study, synthesis of a hydrogel consisted of a coordination bond network between small organic molecules and transition metals had been carried out. By adding a tackifying material to the gel, the potential of the gel to be used as an adhesive material had been also confirmed. Synthesis of the adhesive had been done with simple mixing of 3 components: tannic acid, transition metal, and polymer. The tannic acid molecule possesses multiple hydroxyl groups that can form coordination bonds with the transition metals and hydrogen bonds with the hydrophilic polymers. Due to the morphology of the metal-organic complex and polymer dispersed in water, the fabricated material exhibited high adhesiveness and cohesiveness. Optimizing the rheological property had been conducted for use in adhesive by the synthesis with varying the transition metal (Fe³⁺, Ti⁴⁺), polymer, and treatment conditions. Rheological measurement results demonstrate the promising potential of the material as a bio-compatible and versatile pressure-sensitive adhesive with both high adhesiveness and cohesiveness.

• Journal of the Korean Institute of Educational Facilities
• /
• v.22 no.3
• /
• pp.21-29
• /
• 2015

Jinhae's educational facilities had been located in the most integrated area at the beginning. As Jinhae's spatial layout has been in a rapid growth by constructing new towns and experiencing major consolidations over years, it was argued that this morphological transformation inevitably brought to the change of the characteristics of educational facilities' arrangement. In this reason, a number of studies have discussed the ways of how they have been settled down from the beginning of Jinhae. However, they did not take into an account of both the first consolidation happened in 1985 and the second one in 2013. This paper therefore aims to investigate how Jinhae's urban structure has been transformed between the two consolidations from a syntactical perspective, and then to interpret characteristics of educational facilities arrangement accordingly. This study finds out that when Jinhae experienced the first consolidation, educational facilities were occupied in highly segregated areas in terms of both global and local integration values. However, their locations turned out to be more intelligible after the second consolidation. This suggests that they have a significant effect on the process of urban growth at local level. Although the educational facilities particularly in Pungho and Ungchun are in highly integrated spaces at global level, they are still less intelligible.

• Korean Journal of Materials Research
• /
• v.27 no.3
• /
• pp.144-148
• /
• 2017

The effects of an excess of Bi on the piezoelectric and dielectric properties of $0.60Bi_{1+x}FeO_3-0.40BaTiO_3$ (x = 0, 0.01, 0.03, 0.05, 0.07) were investigated. The ceramics were processed through a conventional solid state reaction method and then quenched after sintering at different temperatures in the range of $980{\sim}1070^{\circ}C$. A single perovskite structure without any secondary phase was confirmed for all compositions and temperatures. It was found that excess Bi reduced the sintering temperatures, acted as a sintering aid and enhanced the properties in combination with quenching. Curie temperature ($T_C$) was found to slightly increase due to the presence of excess Bi; electrical properties were also improved by quenching. At x = 0.03 and $1030^{\circ}C$, remnant polarization ($2P_r$) was as high as $45.4{\mu}C/cm^2$ and strain at 40 kV/cm was up to 0.176 %.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2133-2141
• /
• 2012

The Purpose of this study was to report magnetic resonance imaging(MRI) changes of six cases of Lumbar herniated disc which was treated with spinal decompression therapy, oriental medical therapy. 'Disc heights' were measured on sagittal view of $T_2$-weighted MRI. Size of the herniated disc was measured by MRI and 'disc herniations index'. The grading system and algorithm for 'disc degeneration' were based on MRI signal intensity, disc structure, distinction between nucleus and anulus, and disc height. Data for disc height, disc herniations index and disc degeneration grade were collected before and after the treatment together with calculation from the MRI. Case studies were showed that decompression therapy for the herniated disc has an positive effect on disc herniations index, disc regeneration, not disc heights. The clinical evidence for the use of decompression in herniated disc remains inconclusive because of limited researches. Further trials, which give attention to these areas, are needed before any firm conclusions may be made.

• Journal of Broadcast Engineering
• /
• v.15 no.2
• /
• pp.173-181
• /
• 2010

In this paper, we propose a new resource allocation scheme for an OFDMA relay network with multicells. In the proposed scheme, by sharing the channel state information (CSI) between base stations, resources are allocated to users and relays to maximize the overall sum of the achievable rate under fairness constraints. In order to reduce the computational complexity, a resource allocation scheme is proposed by separating subcarrier allocation and power allocation into two parts. First of all, by considering inter-cell interference (ICI), a subcarrier is allocated to a user-relay pair, and power is allocated relays. Simulation results show that the proposed scheme achieves higher spectral efficiency per subcarrier than the static scheme and reduces the outage probability compared to the static and greedy schemes.

• Journal of the Korea Institute of Building Construction
• /
• v.11 no.6
• /
• pp.547-556
• /
• 2011

The primary factors affecting concrete sulfate resistance are the chemical composition of the Portland cement, and the chemistry and quantity of mineral admixtures. To investigate the effect of those on the sulfate attack, the testing program involved several different mortar mixes using the standardized test, ASTM C1012. Four different cements were evaluated, including one Type I cement, two Type I-II cements, and one Type V cement. Mortar mixes were also made with mineral admixtures, as each cement was combined with three different types of mineral admixtures. One Class F fly ash, one Class C fly ash, and one ground granulated blast furnace slag (GGBFS) were added in various percent volumetric replacement levels. Expansion measurements were taken and investigated with the expansion criteria recommended by ASTM.

• Journal of Korean Association for Spatial Structures
• /
• v.8 no.1
• /
• pp.41-48
• /
• 2008

Spatial structure is an appropriate shape that resists external force only with in-plane forte by reducing the influence of bending moment, and it maximizes the effectiveness of structure system. the spatial structure should be analyzed by nonlinear analysis regardless static and dynamic analysis because it accompanys large deflection for member. To analyze the spatial structure geometrical and material nonlinearity should be considered in the analysis. In this paper, a geometrically nonlinear finite element model for plane truss structures is developed, and material nonlinearity is also included in the analysis. Arc-length method is used to solve the nonlinear finite element model. It is found that the present analysis predicts accurate nonlinear behavior of plane truss.

• The Journal of Society for e-Business Studies
• /
• v.17 no.2
• /
• pp.23-38
• /
• 2012

The purpose of this study is to find factors affecting knowledge sharing activities which have two aspects-quantity and quality. We surveyed the members of a virtual community of practice called "UPOW.com". It is dedicated to sharing knowledge about job related problems, questions, experience of educational official. This study derived factors from social cognitive theory and social capital theory. The findings of the study can be summarized as follows; first, quality of shared knowledge and quantity of knowledge sharing both have positive effect on knowledge utilization. Second, individual factors and social relations have positive effect on quantity of knowledge sharing. However, individual factors' effects on quantity of knowledge sharing are not significant. These results have academic implications to find factors affecting both side of knowledge sharing. Also these finding will give an insight to develop virtual community of practice for an organization's sustained competitiveness.

• Korean Journal of Veterinary Research
• /
• v.14 no.2
• /
• pp.159-171
• /
• 1974

Histological and histochemical studies were made on the lining epithelia of the various ducts in epidymis of the Rooster and absorptive function of the canal epithelial cells in the Rooster epididymis were also investigated after administration of India ink. The results obtained were summerized as follows; 1. Epihtelium lining the rate testis was mainaly composed of single later of cuboidal cells, and was partially composed of flattened squamous or low columnar cells. Efferential ductules were characterized by having many villous projections orrfolds which extened into the lumen, and were lined by stereociliated pseudostratified epithelium which consisted of manily ciliated columnar cells, a few scattered clear cells and basal cells. Connecting ductules were lined by ciliated pseudostriatified colummnar epithelium in which ciliated columnar cells, clear cells and basal cells were noted. Epididymal ducts were lined by pseudostratified epidhelium in which columnar and basal cells were noted. 2. PAS-granules, saliva resistant were noted mainly in the epithelial cells of efferential and connecting ductules. 3. Sudan black B stained heavily the granules in the epithelial cells of sufferential and connecting ductules. 4. The granules reactive to acid phosphatase most abundant in the epithelial cells of efferential ductules and were lesser amount in the epithelial cells of connecting ductules where as very few or no granules were seen in the rest of the ducts. 5. Alkaline phosphatase activity was most prominent but discontinuous in the luminal surface of the epithelium of efferential ductules and less marked in the connecting ductless. No enzyme activity was noted in the canal epithelium of epididyml duct. 6. India ink granules were most numerous in the epithlial cells of efferential ductules and were a few in connecting ductules. Very few or no granules of India ink were noted in the other types of the ducts. India ink granules in the epithelium increased gradually as the time after the administration of India ink (one up to twenty-nine hours) has proceeded. From those results it is suggested that epithelial cells of efferential and connecting ductules have active absorptive function, whereas the rest of duct system in the epididymis of the Rooster may be the mere pathway of the seminal fluid without significant modification of its constituents.