• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.29-39
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• 1989

In this work, a numerical and experimental study was done to get an optimum cam profile considering dynamic characteristics of a cam-valve system. First of all, a four degree of freedom dynamic model was set up for an OHV type cam-valve acceleration while not modifying original cam shape greatly. Also another optimization which aims to enlarge the valve displacement area while reducing the peak valve acceleration, was tried. The optimized cam profile was tested experimentally and found that the measured valve displacement and pushrod force show only very small error from the analytically predicted model simulation results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.1
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• pp.73-82
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• 2018

Urban parks are important bird habitat in cities. Various studies have evaluated the habitat function of urban parks focused on field surveys. In this study, we performed applicability of NDVI obtained from Landsat 8 OLI image as a factor for spatial planning considered bird diversity. This study was classified with green boundary into three groups using NDVI's value. Environmental variables were calculated by the green area ratio of the surrounding area from 100m to 500m at each groups. The 20 environmental variables such as park area, park shape index, canopy of tree, etc. were derived, the regression analysis was performed as a dependent variable for the bird diversity of urban parks. As a result, the park area and the green area ratio of Group 3, classified high NDVI, within the 100m buffer were adopted as the variables in the regression model. In other words, it was confirmed that as the park becomes larger, the distribution of key green areas within a radius of 100m of the parks becomes higher, the diversity of bird species has increased. It was appropriate to use satellite image, NDVI to analyze species diversity in urban area.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.560-567
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• 2005

Three groups of exopolysaccharides (EPSs) (designated as Fr-I, Fr-II, and Fr-III) were isolated from the culture filtrates of Paecilomyces sinclairii by gel filtration chromatography on Sepharose CL-4B. Their molecular characteristics were examined by multi-angle laser light scattering (MALLS) connected online to a size exclusion chromatography (SEC) and refractive index (RI) detector system. The weight-average molar mass of Fr-I, Fr-II, and Fr-III of EPSs were determined to be $1.540{\times}10^6,\;6.302{\times}10^4$, and $9.389{\times}10^4\;g/mol$, respectively. All three EPSs showed a fairly low polydispersity indice, ranging from 1.008 to 1.059 (nearly mono disperse behavior), and showed different carbohydrates and amino acids compositions; all fractions of EPSs consisted of mainly cystine, valine, and arginine in the protein moiety, and mainly ribose, galactose, and glucose in the carbohydrate moiety. The determination of gyration radii of the EPSs in SEC/MALLS analysis revealed the molecular shape of the Fr-I to be a rod-like structure, whereas the Fr-II and Fr-III had a random-coil structure in an aqueous solution.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.109-110
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• 2018

Preloading Strut applied during installation of the wall jack, but additionally serves to minimize the displacement of soil pressure acting upon dissolution due to the difficulty. In this study, we developed an index of support for the release of stress to facilitate the dismantling of the strut uninstall. The refractive support the axial force acting on the strut are supportable, is refracted at minimum load, disassembly should be easy. In order to find the optimal shape and structural stability of the refractive support We have performed the numerical analysis and performance test to determine the final model. We carried out model tests and UTM test in order to understand the refractive performance and durability of the refractive support for optimal model. Results of the test UTM is refracted all shot 5 times within a target hit number, it was found that there is no problem of the refractive performance. Further, the results of model experiments, it was found that to ensure sufficient durability more than the performance target value of the pin joint support structure.

• Structural Engineering and Mechanics
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• v.38 no.6
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• pp.715-732
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• 2011

A novel structural damage detection method with a new damage index has been recently proposed by the authors based on the statistical moments of dynamic responses of shear building structures subject to white noise ground motion. The statistical moment-based damage detection (SMBDD) method is theoretically extended in this paper with general application. The generalized SMBDD method is more versatile and can identify damage locations and damage severities of many types of building structures under various external excitations. In particular, the incomplete measurements can be considered by the proposed method without mode shape expansion or model reduction. Various damage scenarios of two general forms of building structures with incomplete measurements are investigated in consideration of different excitations. The effects of measurement noise are also investigated. The damage locations and damage severities are correctly identified even when a high noise level of 15% and incomplete measurements are considered. The effectiveness and versatility of the generalized SMBDD method are demonstrated.

• Computational Structural Engineering
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• v.11 no.1
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• pp.261-274
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• 1998

In this paper, local and global error estimates for the element-free Galerkin (EFG) method are proposed. The essence of proposed error estimates is to use the difference between the values of the projected stress and these given directly by the EFG solution. The stress projection can be obtained simply by taking product of shape function based on a different domain of influence with the stresses at nodes. In this study, it was found that the effectivity index is optimized if the domain of influence in stress projection procedure is the smallest that retains regularity of the matrices in EFG. Numerical tests are shown for various 1D and 2D examples illustrating the good effectiveness of the proposed error estimator in the global energy norm and in the local error estimates.

• Journal of the Korean Graphic Arts Communication Society
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• v.23 no.2
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• pp.1-14
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• 2005

Generally, printing inks are composed of pigment, vehicle and additive. Among others, the vehicle transfers the pigment to substrate and then binds it on the surface. So, rheological properties of the vehicle are an important factor which has influence on printability. Thus, in this study, rheology of the vehicle was investigated by using rotational rheometer according to molecular weight of resin. Also, emlusion rheology of water in oil type and its microstructure were examined with increasing the shear rate. Consequently, the following results were obtained: (1) By viscometric flow test, zero shear viscosity and shear thinning index of vehicle increased with increasing the molecular weight of resin. (2) By relaxation and creep test, relaxation time and retardation time of vehicle increased with increasing the molecular weight of resin. (3) By frequency sweep test, crossover point of vehicle increased with increasing the molecular weight of resin. (4) G' and G" of emlusions increased with increasing the molecular weight by amplitude sweep test. (5) The shape of water drop in emlusions was changed to the capillary tube.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.445-452
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• 2006

The number of species and forest area has decreased as urbanization is progressed. The landscape degradation was examined by analyzing vegetation map, satellite image and characteristics of actual vegetation. The study was conducted in Mt. Baekja and its surroundings located on Gyeongsan city, southeastern Korea. As the result of landscape analysis, agricultural field was a characteristic attribute of the study area. Lowlands of this study area were occupied by agricultural field and various plantations. For 15 years from 1987 to 2002, forest area decreased from 2,072.9 ha to 1,853.2 ha, and shape index and fractal dimension of vegetation patches increased from 1.32 to 1.65 and from 1.05 to 1.09, respectively. Pinus densiflora Siebold & Zucco. community showed the highest species diversity, whereas Larix kaempferi (Lamb.) Carriere community showed the lowest species abundance. As forest management implications, monitoring of endangered plant species (Jeffersonia dubia (Maxim.) Benth. & Hook.f. ex Baker & S.Moore), and restoration of lowland forest from plantation to natural forest were discussed. Further, establishment of greenways utilizing existing streams, roadside, and public facilities were recommended.

• Journal of Aquaculture
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• v.12 no.1
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• pp.57-62
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• 1999

Experiments were performed to study the activity and fertility of grey mullet (Mugil cephalus) sperm after the courses of cold storage and cryopreservation. The head of spermatozoon showing spherical shape was sized $1.26{\pm}0.08 \{mu}textrm{m}$ in diameter and its nucleus contained numerous granular chromatins. Flagellum of tail showed typical 9＋2 structure. Preservation of grey mullet sperm was the most effective when it was stored with serum of the same species at $0^{\circ}C$ and sperm activity index was similar in egg-tris, 0.1 M, 0.3 M and 0.5 M glucose. When grey mullet sperm were cryopreserved in MFRS as diluent with 10% dimethyl sulfoxide was effective compared with other diluents. Some of post-thawed spermatozoa showed the enlarged head and ruptured plasma membrane compared with unfrozen spermatozoa.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.1
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• pp.125-129
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• 2007

The effects of Crataegus pinnatifida bunge powder(CP) on dough characteristics and bread quality were evaluated. Breads were prepared with the addition of 0, 3, 6 and 9% CP to the basic formulation. The pH of dough added with CP ranged from 5.26 to 5.34, while control dough had a pH of 5.80. The loaf volume index of bread prepared with $3{\sim}9%$ CP decreased by $5.4{\sim}16.9%$ Hardness increased with the addition of CP, but the cohesiveness and springiness decreased with the addition of 3 and 6% CP and increased with the addition of 9% CP. Color L value of the bread crust and crumb decreased with CP and color a and b values of the bread crumb increased with CP. The sensory quality of bread with 6 or 9% Crataegus pinnatifida bunge powder, as estimated by shape, flavor and overall quality, was worse than that of control bread, while bread with 3% Crataegus pinnatifida bungs powder had the best quality.