• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.3
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• pp.1-17
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• 2004

The focus of this study is the promotion of green area volumes and their naturalness, water circulation system, decline of entropy, creation of biological habitats and linkage of separated urban green space. Re-presentative urban biotope survey sites were categorized as urban biotope, semi-natural biotope, and natural forest. In the urban biotope, a residential biotope was constructed near the Han river and in mountain areas. The green-area ratio at the housing complex was about 25%. GVZ(Grunvolumenzahl) was 0.35m$^3$/m$^2$ at the 5∼10-story housing complex, and 1.53m$^3$/m$^2$ over the 11-story. As for the green-area structure of the housing complex, canopy layer, understory layer, and shrub layer were not differentiated and the green-area volume was not high enough. The green-area ratio of school areas as a public area biotope was 5∼20%. GVZ was 1.12m$^3$/m$^2$ at Myungduk High School, and 1.78m$^3$/m$^2$ at Jeonggok Elementary School. In order to convert the urban biotope into an ecological area, green areas around the buildings should be connected to urban buffer green areas, and multi-layer structures should be established with natural plant species. In the semi-natural biotope, neighbor parks were created park in the vicinity of the natural forests. GVZ was 0.28m$^3$/m$^2$, and plantation was established with single layer structure and was definitely insufficient for the area. The urban buffer green areas have been established in strip corridors with the width of 20∼123m. In those areas, GVZ was 0.16∼0.27m$^3$/m$^2$ and had a deficient canopy layer, understory layer, and shrub layer. Soil conditions were not favorable for tree growth. In the natural biotope, GVZ of the plantation was 1.03∼1.5m$^3$/m$^2$ but the high crown closure of this area reduces the chance of species change and succession. GVZ of natural forest was 2.53∼2.57m$^3$/m$^2$. It is desirable to plant diverse plants and the natural forest should be succeeded by broad-leaf deciduous tree species. To improve the value of biotope at Kangseo-Gu, building height needs to be limited to reduce the environmental deterioration in the city. In order to maintain the water circulation system, water-permeable material is recommened when the urban surface areas are paved. The establishment of a water circulation system will improve ground water levels, soil moisture, water quality, and habitats. In order to improve biological diversity, it is desirable to have multi-layer structures in urban green areas with native species.

• Structural Engineering and Mechanics
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• v.49 no.5
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• pp.537-554
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• 2014

In this paper, free vibration of a sandwich curved beam with a functionally graded (FG) core was investigated. Closed-form formulations of two-dimensional (2D) refined higher order beam theory (RHOBT) without neglecting the amount of z/R was derived and used. The present RHOBT analysis incorporated a trapezoidal shape factor that arose due to the fact that stresses through the beam thickness were integrated over a curved surface. The solutions presented herein were compared with the available numerical and analytical solutions in the related literature and excellent agreement was obtained. Effects of some dimensionless parameters on the structural response were investigated to show their effects on fundamental natural frequency of the curved beam. In all the cases, variations of the material constant number were calculated and presented. Effect of changing ratio of core to beam thickness on the fundamental natural frequency depended on the amount of the material constant number.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.36-44
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• 2013

This study investigates life, damage and durability through the analyses of fatigue load and vibration on disk brake models of A, B and C. Maximum equivalent stress is happened at the inside of disk brake on these models. As there are A, B and C models by order of life, model A has the most stable strength on fatigue analysis, The deformations at 3 kinds of models become nearly same on natural frequency analysis. The maximum total deformation and equivalent stress is shown at 1617Hz by harmonic vibration analysis on these models. As there are A, B and C models by order of deformation and stress, model A becomes lowest and safest. This study result can be effectively utilized with the design of brake disk in order to improve durability and prevention against its fatigue damage and vibration.

• Journal of KSNVE
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• v.5 no.3
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• pp.403-411
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• 1995

Square beam type piezoelectric vibrating gyro is developed for the measurement of angular velocity, which is compact, small in size and mass- producible. It features that three pieces of piezoelectric ceramics and bonded onto one face of equilateral square bar type gyro head. Two of them are used as sentuators which drive the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head with its fundamental natural frequency. Matching two fundamental natural frequencies in the gyro head with its driving frequency is found critical in the design of vibration gyro. Calibration results show that the vibrating gyro developed has the dynamic characteristics of first-order system within the frequency range of interest, which can be easily compensated by a lead compensator.

• Bulletin of the Korean Mathematical Society
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• v.47 no.6
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• pp.1285-1296
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• 2010

We give criterions for a submanifold to be an extrinsic sphere and to be a totally geodesic submanifold by observing some Frenet curves of order 2 on the submanifold. We also characterize constant isotropic immersions into arbitrary Riemannian manifolds in terms of Frenet curves of proper order 2 on submanifolds. As an application we obtain a characterization of Veronese embeddings of complex projective spaces into complex projective spaces.

• Structural Engineering and Mechanics
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• v.48 no.3
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• pp.415-434
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• 2013

This work is concerned with transverse vibrations of axially traveling nanobeams including strain gradient and thermal effects. The strain gradient elasticity theory and the temperature field are taken into consideration. A new higher-order differential equation of motion is derived from the variational principle and the corresponding higher-order non-classical boundary conditions including simple, clamped, cantilevered supports and their higher-order "offspring" are established. Effects of strain gradient nanoscale parameter, temperature change, shape parameter and axial traction on the natural frequencies are presented and discussed through some numerical examples. It is concluded that the factors mentioned above significantly influence the dynamic behaviors of an axially traveling nanobeam. In particular, the strain gradient effect tends to induce higher vibration frequencies as compared to an axially traveling macro beams based on the classical vibration theory without strain gradient effect.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.1
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• pp.67-73
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• 2002

This paper presents a new design method of optimal continuous deadbeat controller by using second-order smoothing elements. The continuous deadbeat controller is made of a serial integral compensator and a local feedback compensator introduced into the state feedback loop. The decision method of the damping factor and the natural angular frequency of the smoothing element is described. A numerical example is given to show how well input-output characteristics are improved. Especially according to the variable input and disturbance, corresponding CDBC design method is suggested. By computer simulations, control inputs and system outputs are shown to have desirable property such as smoothness.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.2
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• pp.39-52
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• 1994

Existing natural resources were analyzed in regional scale in order to suggest natural park guidelines as a previous step of conservation plan. Results of both existing natural resources and land potentiality in preceding paper were combined to suggest comprehensive and qualitative method for understanding of natural land. Regional characteristics of natural park were, then, analyzed by this method, and specific planning guidelines were discussed. The existing natural resources were analyzed by the degree of location quotient, which were found by comparison of the grade of vegetation naturalness and the bio-physical land unit in preceding paper. Then, allowance of existing natural resources was identified, and importance of protection was described based on this result. The bio-physical land unit on Tokyo Province was found to be composed by smaller land units, which had a variety of relationship with grade of vegetation naturalness: from the specific(1st) to many stages(5th). This meant a characteric of each land unit. By this combined approach, the characteristics and spatial distribution of natural land were discussed in the regional scale, and characteristic of nateral park were analyzed in terms of natural location. National park were located in the land unit where both land capability and importance of portection were the 6th. Quasi national park and 1 province natural park were located in the land unit where land capability was the 6th and importance of protection were the 5th. Seven province natural parks were located in the land unites were both criteria under the 5th were mixed. based on the results of this study, the followings were suggested for specific planning guidelines in the case of Takao quasi nation park: (a) conservative land use within the limit of carrying capacity of this area by the conservation of biotic and abiotic natural resources, (b) conservation of both natural and semi-natural vegetation, (c) utilization of this area as a urban forest.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.295-302
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• 1989

This study was carried out as a preliminary test to investigate the improvement of soysauce and soybean paste for natural food. The soybean was treated on raw, soaked, roasted, and steamed condition and it was maked that rice koji was inoculated by Asp. oryzae, Asp. niger, Asp. awamori and on natural condition fermented. They were maked raw soybean-soypaste $(S_0)$, soaked soybean-soypaste $(S_1)$, roasted soybean-soypaste $(S_2)$, and steamed soybean-soypaste $(S_3)$ from soybean (60%), rice koji (30%) and salt (10%) respectively in order to investigate the changes of enzymes activity(amylase, protease, lipase and lipoxygenase activity) during fermentation of them. The results obtained were summarized as follows; Amylase activity was in the order of natural fermented microorganisms>Asp. oryzae>Asp. awamori>Asp. niger in the microorganisms, and $S_0>S_1>S_2>S_3$ in the soybean treatments. Protease activity was in the order of natural fermented microorganisms>Asp. niger>Asp. oryzae>Asp. awamori in the microorganisms, and $S_3>S_2>S_1>S_0$ in the soybean treatments. Lipase activity was a similar tendency in the microorganisms, but it was in the order of $S_0>S_1>S_3>S_2$ in the soybean treatments. Lipoxygenase activity was in the order of natural fermented microorganisms>Asp. oryzae>Asp. awamori>Asp. niger in the microorganisms, and $S_0>S_1>S_3>S_2$ in the treatments.

• Journal of the Korean School Mathematics Society
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• v.20 no.2
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• pp.141-161
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• 2017

As it's important to understand the order of operation in the mixed calculation of natural number and perform it, mathematics curriculums and textbooks focused that students can calculate with understanding the order of operation and its principles. For attaining the implications of teaching about the mixed calculations, this study analyzed the problem solving abilities and error types of 67 elementary students and 57 pre-service teachers using questionnaire which was developed in this study and composed of numeric expressions and word problems. The conclusions drawn from this study were as follows: Students were revealed the correct rates(86.2% and 73.5%) in numeric expressions and word problems, but they were showed the paradigmatic error types-the errors of the order of operation and the composition of numeric expression from word problems. Even though the correct rates of the preservice teachers were extremely high, the result of problem solving processes required that it's needed to be interested in teaching the principles of the order of operation in the mixed calculations. In addition, subjects were revealed the problems about using parentheses and equal sign.