• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.750-753
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• 1998

This paper gives a simple parameterization of all stable unbiased filters to solve the suboptimal mixed $H_2/H_{\infty}$ filtering problem. Using the central filter, mixed $H_2/H_{\infty}$ filter is designed which minimizes the upper bound for the $H_2$ norm of the transfer matrix from a white noise to the estimation error subject to an $H_{\infty}$ norm constraint on the transfer matrix from an energy-bounded noise to the estimation error. The problem of finding suitable estimator gain can be converted into a convex optimization problem involving linear matrix inequalities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.5
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• pp.398-410
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• 2001

The flow and heat transfer characteristics for three-dimensional mixed convection flows in a radiator flat tube with U--shaped grooves are analyzed numerically. The flow and temperature fields are calculated by using the modified SIMPLE algorithm for irregular geometry. One tube specification among the various flat tube exchangers is recommended by considering the heat transfer and pressure drop. The effects of variation of coolant flow conditions and external air conditions on the flow and the thermal characteristics for the selected tube are investigated. the results show that inlet velocity of coolant flow is the very important factor in heat transfer and pressure drop, and top side is better position than the others as fin cleave to tube.

• Journal of the Korean Ceramic Society
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• v.55 no.1
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• pp.1-20
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• 2018

Semiconducting nanomaterials have attracted considerable interest in recent years due to their high sensitivity, selectivity, and fast response time. In addition, for portable applications, they have low power consumption, lightweight, simple in operation, a low maintenance cost. Furthermore, it is easy to manufacture microelectronic sensor structures with metallic oxide sensitive thin layers. The use of semiconducting metal oxides to develop highly sensitive chemiresistive sensing systems remains an important scientific challenge in the field of gas sensing. According to the sensing mechanisms of gas sensors, the overall sensor conductance is determined by surface reactions and the charge transfer processes between the adsorbed species and the sensing material. The primary goal of the present study is to explore the possibility of using semiconducting mixed metal oxide nanostructure as a potential sensor material for selective gases.

• Structural Engineering and Mechanics
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• v.20 no.4
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• pp.405-420
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• 2005

In this paper, a hybrid/mixed nonlinear shell element is developed in polar coordinate system based on Hellinger/Reissner variational principle and the large-deflection theory of plate. A numerical solution scheme is formulated using the hybrid/mixed finite element method (HMFEM), in which the nodal values of bending moments and the deflection are the unknown discrete parameters. Stability of the present element is studied. The large-deflection analyses are performed for simple supported and clamped circular plates under uniformly distributed and concentrated loads using HMFEM and the traditional displacement finite element method. A parametric study is also conducted in the research. The accuracy of the shell element is investigated using numerical computations. Comparisons of numerical solutions are made with theoretical results, finite element analysis and the available numerical results. Excellent agreements are shown.

• Journal of Korea Multimedia Society
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• v.24 no.10
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• pp.1358-1368
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• 2021

A research on agricultural automation is a main issues to overcome the shortage of labor in Korea. A sweet persimmon farmers need much time and labors for classifying profitable sweet persimmon and ill profitable products. In this paper, we propose a mixed two-step synthetic neural network model for efficiently classifying sweet persimmon images. In this model, we suggested a surface direction classification model and a quality screening model which constructed from image data sets. Also we studied Class Activation Mapping(CAM) for visualization to easily inspect the quality of the classified products. The proposed mixed two-step model showed high performance compared to the simple binary classification model and the multi-class classification model, and it was possible to easily identify the weak parts of the classification in a dataset.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.40-48
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• 2009

In this article, scheduling of a casting sequence is studied in a casting foundry which must deliver products according to the Just-in-time(JIT) production policy of a customer. When a foundry manufactures a variety of casts with an identical alloy simultaneously, it frequently faces the task of production scheduling. An optimal casting schedule should be emphasized in order to maximize the production rate and raw material efficiency under the constraints of limited resources; melting furnaces and operation time for a casting machine. To solve this practical problem-fulfilling the objectives of casting the assigned mixed orders for the highest raw material efficiency in a way specified by the customer's JIT schedule, we implement simple integer programming. A simulation to solve a real production problem in a typical casting plant proves that the proposed method provides a feasible solution with a high accuracy for a complex, multi-variable and multi-constraint optimization problem. Employing this simple methodology, a casting foundry having an automated casting machine can produce a mixed order of casts with a maximum furnace utilization within the due date, and provide them according to their customer's JIT inventory policy.

• Journal of Pharmacopuncture
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• v.24 no.3
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• pp.142-151
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• 2021

Objectives: Although Korean Medicine (KM) subsidized by the National Health Insurance (NHI) has been used for a long time, there has been no active analysis using claims data. Therefore, the purpose of this study was to examine the NHI KM utilization trend using NHI statistics and to measure the level of market concentration by year. Methods: By restructuring the contents of NHI Statistics for Pharmaceuticals for 2010-2019, the claim cases, costs, and annual growth rates of KM were demonstrated by year, sex, age group, region, therapeutic group, and KM treatment. The proportion of highly used k treatments in cost was calculated as the concentration ratio (CR) k and its trend by year was investigated. Results: In 2019, the NHI cost on KM amounted to ₩38.2 billion KRW, increasing by 11.6% per year on average in 2010-2019. Notably, KM was used more frequently among women and patients aged ≥ 65 years, and the mixed formulation accounted for 95% of the total cost of KM. The CR of the simple formulation increased rapidly, whereas that of the mixed formulation remained constant. In 2019, three simple formulation treatments- peony, licorice, and ginseng- accounted for 93.8% of the total cost for KM (CR3 = 93.8%). Conclusion: NHI KM is rapidly increasing. Investigating the CR of KM confirmed that KM prescriptions have been concentrated in small numbers over the past 10 years.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.843-854
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• 1997

Sixteen mammary gland tumors were collected from Seoul National University and Kangwon National University. The average age of the bitches with mammary gland tumor was 10 years. Total 17(60.7%) out of 28 tumor masses observed in 4th and 5th glands. Classification of these tumors according to Hampe and Misdorp were simple adenoma, complex adenoma, benign mixed tumor, papillary adenocarcinoma, solid adenocarcinoma and malignant mixed tumor. Immunohistochemical reaction of the intermediate filaments against normal canine mammary gland showed as followed; anti-cytokeratin 18 was strong and anti-cytokeratin 14 was moderate to the luminal epithelium. Anti-cytokeratin 14 and anti-pancytokeratin to the myoepithelium were showed strong, but anti-vimentin was weak in reactivity. Anti-vimentin to the interstitial cells was represented strong reactivity. The origin of cartilage in mixed tumor of canine mammary gland was studied immunohistochemically with antibodies against intermediate filament. In mammary gland mixed tumors, cartilage tumor tissues were surrounded with the irregularly demarcated three zones composed of adjacent star shaped cells in myxoid areas, proliferative spindle shaped cells and basal located proliferated cells. From basal proliferated cells to star shaped cells, the immunohistochemical reactivity of myoepithelium specific anti-pancytokeratin was decreased gradually and the reactivity of interstitial cell specific anti-vimentin was increased gradually. Based on these immunohistochemical staining patterns, we suggested that the origin of cartilagenous components in canine mammary gland mixed tumor is most likely to the proliferation and metaplsia of myoepithelium.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1120-1122
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• 1995

This paper presents a 2-stage, simple, power-efficient 3V CMOS operational amplifier and its equation based design optimization. Because of its simple structure, it is very suitable as a VLSI library cell in analog/digital mixed-mode systems. The op-amp, which contains a constant-$g_m$ rail-to-rail input stage and a simple feedforward class-AB rail-to-rail output stage, is analyzed and the results are presented in the form of design equations and procedures, which provide an insight into the trade-offs among performance requirements. The results of SPICE simulations are shown to agree very welt with the use of design equations.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.1
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• pp.27-32
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• 2002

In this study, estimate of Mechanical Properties depending on Injected direction in Polymer for Automobile Application. The used materials is polyamid(nylon6), polypropylene(PP) of a simple component and its mixed, reinforced glass fiber(15%) in polyamid. One side direction of a simple component is highest strength and the two sides direction of multicomponent appear lowest strength. This is caused by effects of weldline, imperfect fusion and impregnation of multicomponent. To improve mechanical properties, it is necessary to minimize of weldline, compatibility, perfect fusion and impregnation in multicomponent polymer.