• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.133-138
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• 1999

The structure of shoot apex in zygotic and somatic embryos of Daucus carota L. cv. Hongshim was observed by using SEM and longitudinal sections. Shoot apex of zygotic embryo was of an inverted boat shape, and these of two, three and four cotyledon somatic embryos were of an inverted boat shape, a pyramid shape and a convex diamond shape, respectively. In zygotic embryo shoot apex is consisted of small cells which are arranged in layers (tunica) and show corpus in central region. In somatic embryos shoot apices are consisted of somewhat large cells which are arranged in irregularly or slight regularly.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.9-13
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• 2014

Friction stir welding (FSW) was successfully performed about 900MPa grade Twinning Induced Plastisity (TWIP) steel. A PCBN tool with convex-type shoulder was applied. Optimal process conditions were deduced. Microstructure and mechanical properties such as hardness, tensile strength and impact absorbed energy were observed and evaluated, respectively. An optical microscope (OM) and a field emission scanning electron microscope (FE-SEM) was selected for observing the grain structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1249-1254
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• 2006

Existing adaptive observers may cause the parameter drifts due to disturbances even if state estimation errors remain small. To avoid the drift phenomena in the presence of bounded disturbances, several robust adaptive observers have been introduced addressing bounds in state and parameter estimates. However, it is not easy for these observers to manipulate the size of the bounds with the selection of the observer gain. In order to reduce estimation errors, this paper introduces the (equation omitted) gain minimization problem in the adaptive observer structure, which minimizes the (equation omitted) gain between disturbances and estimation errors. The stability condition of the adaptive observer is reformulated as a linear matrix inequality, and the observer gain is optimally chosen by solving the convex optimization problem. The estimation performance is demonstrated through a numerical example.

• International Journal of Control, Automation, and Systems
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• v.4 no.5
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• pp.645-652
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• 2006

In this paper a new type of filter, called the $H_2/H_{\infty}$ FIR filter, is proposed for discrete-time state space signal models. The proposed filter requires linearity, unbiased property, FIR structure, and independence of the initial state information in addition to the performance criteria in both $H_2$ and $H_{infty}$ sense. It is shown that $H_2,\;H_{\infty}$, and $H_2/H_{\infty}$ FIR filter design problems can be converted into convex programming problems via linear matrix inequalities (LMIs) with a linear equality constraint. Simulation studies illustrate that the proposed FIR filter is more robust against temporary uncertainties and has faster convergence than the conventional IIR filters.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.225-228
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• 2005

The purpose of this study is to investigate effects of the plastic/elastic deformation energy on wet etching characterization on the surface of material by using the nanoindentation and HF wet etching technique. Indents were made on the surface of Pyrex 7740 glass by the hyperfine indentation process with a Berkovich diamond indenter, and they were etched in $50\;wt\%$ HF solution. After etching process, convex structure was obtained due to the deformation-induced hillock phenomena. In this study, effects of indentation process parameters (normal load, loading rate) on the morphologies of the indented surfaces after isotopic etching were investigated from an angle of deformation energies.

• The Pure and Applied Mathematics
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• v.10 no.2
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• pp.127-132
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• 2003

The object of this paper is to extend and generalize the work of Brosowski ［Fixpunktsatze in der approximationstheorie. Mathematica Cluj 11 (1969), 195-200］, Hicks & Humphries ［A note on fixed point theorems. J. Approx. Theory 34 (1982), 221-225］, Khan & Khan ［An extension of Brosowski-Meinardus theorem on invariant approximation. Approx. Theory Appl. 11 (1995), 1-5］ and Singh ［An application of a fixed point theorem to approximation theory J. Approx. Theory 25 (1979), 89-90; Application of fixed point theorem in approximation theory. In: Applied nonlinear analysis (pp. 389-394). Academic Press, 1979］ in metric spaces having convex structure, and in metric linear spaces having strictly monotone metric.

• Journal of Life Science
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• v.8 no.5
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• pp.582-588
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• 1998

The male reproductive system of Macrobrachium nipponense consists of a pair of lobulate testes enveloped within a mesenteric sheath extending the length of the carapace. The paired vasa deferentia originated from the mid-lateral region of each testis and extended to the genital pores at the base of the fifth walking legs. The vas deferens has four morphologically distinct regions, i.e., a short and slender proximal region, a long convoluted region, an elongate distal region and an ejaculatory duct that terminates at the genital pore. The sperm mass produced in the testes is surrounded by a basophilic matrix adjacent to the high columnar epithelium and an eosinophilic matrix adjacent to the simple columnar epithelium. The sperm cord is stored in the ejaculatory duct until it is ejaculated. Androgenic gland is found near the subterminal region of the ejaculatory duct between the muscles of the coxopodite of the last thoracic leg. The cell of the androgenic gland is about 6~8 $\mu$m in length, characterized by with extended chromatin in the large nucleus that stained weakly with hematoxylin and there is a large quantity of cytoplasm. The sperm of M. nipponense are typical of the palaemonid type, having a convex, cup shaped head and an elongated spike extending from the centre of the convex head. The spermatophore consisted of an eosinophilic matrix, a basophilic matrix and paired sperm masses which was surrounded by the basophilic matrix. It generally shows a bilaterally symmetrical structure.

• Journal of IKEEE
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• v.11 no.4
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• pp.158-164
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• 2007

In this study, three types of a novel Trench IGBTs(Insulated Gate Bipolar Transistor) are proposed. The first structure has P-collector which is isolated by $SiO_2$ layer to enhance anode-injection-efficiency and enable the device to have a low on-state voltage drop(Von). And the second structure has convex P-base region between both gates. This structure may be effective to distributes electric-field crowded to gate edge. So this structure can have higher breakdown voltage(BV) than conventional trench-type IGBT(TIGBT). The process and device simulation results show improved on-state, breakdown and switching characteristics in each structure. The first one was presented lower on state voltage drop(2.1V) than that of conventional one(2.4V). Also, second structurehas higher breakdown voltage(1220V) and faster turn off time(9ns) than that of conventional structure. Finally, the last one of the proposed structure has combined the two structure (the first one and second one). This structure has superior electric characteristics than conventional structure about forward voltage drop and blocking capability, turnoff characteristics.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.82-89
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• 2010

The studies published up to now, related to the correlation between spatial structure and visitors' behavior in a museum are rather relatively lacking when it comes to the in-depth consideration for the effect of the actual exhibition environment. So the main purpose of this study is to define the correlation between the light environment and the visitors' behavior. Towards this end, this study uses 'space syntax' to quantify the spatial structure with 'integration', 'connectivity' and 'control value'. Meanwhile, 'tracking score' and 'tracking frequency' were selected as the scope among the indices of behavior's analysis. The results of this study are as follows; First, integration and correlation of tracking score and tracking frequency are lowest when it comes to the extra large historical museums where the difference of intensity of illumination by each convex space. Meanwhile, the most considerable effect is exerted by control value. Compared to tracking score, tracking frequency is closely related to 'syntactic variables'. Second, visitors do not take the short cut the dark exhibition space even when very dark exhibition spaces continue after passing through relatively bright space. Analysis of visitors' behavior by control value in the exhibition space composed of this type of intensity of illumination environment is not valid. Third, visitors move to relatively brighter transitional space compared to the exhibition space with low intensity of illumination when passing through dark exhibition continually. Meanwhile, when visitors pass through the exhibition space there is some difference intensity of illumination they move to relatively dark exhibition center among the subsequent exhibition spaces. Accordingly, when the composition of exhibition space that continues onto the environment of low intensity of illumination is inevitable, differentiating intensity of illumination appropriately would be effective in inducing visit to the subsequent exhibition space.

• Korean Institute of Interior Design Journal
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• v.21 no.3
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• pp.182-193
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• 2012

The percentage of senior citizens is increasing in Korea and it is expected to become an "aging society". Problems with the elderly are becoming a big concern, such as physical and mental illness, losing their jobs and having difficulties at home. But, the silver generation, as they are being known, has changed a lot these days. With the aid of medical developments, the elderly's lifespan has become longer, making them more independent and active. Senior Welfare Center's are places where the elderly can spend their golden years in comfort, meaningfully. Senior Welfare Center's these days provide many different programs, which naturally lead to an increase in elderly users. With the rise in welfare centers and users, research on the subject also grew. As this topic has only recently become an issue, there were not many spatial structure studies considering elderly movement. Therefore, there should be spatial structure research that considers older users space awareness and how it can be managed effectively. The goal of this study is to present basic resources for providing a comfortable senior welfare center for elders. This will be based on quantitative analysis derived from spatial structure research along with special construction characteristics based on the institution's general plan. As a research method, Senior Welfare Center's will be categorized into corridor type, hall type, and hybrid types which then be reproduced into a j-graph. Based on this, special structure characteristics and connection links will be comprehended. Then the connection link will be analyzed based on the space syntax result calculated from each type's integration, connectivity, control value, and intelligibility. The analysis result shows that Senior Welfare Center j-graph's average arrangement is hybrid>corridor>hall types. Those elders lacking awareness need easily perceivable spatial structure's and hall type's would be the best choice to increase their awareness as it has high articulation. However, hall type's would be difficult to construct with the size increase, so hybrid type would be the next logical solution. Space with relatively high articulation will need to be planned in hybrid type's where rest areas can be created within the halls in the Welfare Center in connection to its corridors.