• Wind and Structures
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• v.22 no.3
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• pp.349-368
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• 2016

A preconditioning technique is presented for a simultaneous solution to wind-membrane interaction. In the simultaneous equations, a linear elastic model was employed to deal with the fluid-structure data transfer at the interface. A Lagrange multiplier was introduced to impose the specified boundary conditions at the interface and strongly coupled simultaneous equations are derived after space and time discretization. An initial linear elastic model preconditioner and modified one were derived by treating the linearized elastic model equation as a saddle point problem, respectively. Accordingly, initial and modified fluid-structure interaction (FSI) preconditioner for the simultaneous equations were derived based on the initial and modified linear elastic model preconditioners, respectively. Wind-membrane interaction analysis by the proposed preconditioners, for two and three dimensional membranous structures respectively, was performed. Comparison was made between the performance of initial and modified preconditioners by comparing parameters such as iteration numbers, relative residuals and convergence in FSI computation. The results show that the proposed preconditioning technique greatly improves calculation accuracy and efficiency. The priority of the modified FSI preconditioner is verified. The proposed preconditioning technique provides an efficient solution procedure and paves the way for practical application of simultaneous solution for wind-structure interaction computation.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.852-857
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• 1990

The purpose of this paper is to design a robust controller for a class of time-varying systems with bounded disturbance described by the differential equation. The robust desiging method proposed in this paper, called "incentive design method" is different from developed designing methods in the past, and has following properties. The robust control law designed by this method can guarantee a certain value of the cost functional no matter how the disturbance vary within the given bounds. Here, the certain value of the cost functional may not be a saddle-point value, but is the value selected by a system designer. Therefore, the bounded disturbance has at least no bad effect on the value of the cost functional during finite interval of time. The method is based on the theory of incentive differential games. In addition, the form of control law is constructed by the system designer ahead of time. A numerical illustrative example is given in this paper. It is shown from this derivation and this numerical example that the approach developed in this paper is effective and feasible for some practical control problem.l problem.

• Journal of the Korean Regional Science Association
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• v.14 no.2
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• pp.65-75
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• 1998

Education is widely recognized one of main sources for growth. This paper attempts to incorporate the general recognition into formal regional growth model. The model structure is largely neoclassical. It produces a single good with the two factors, educated labor and non-educated labor, via a constant return production migrating to the region with the higher real wage. The educated labor in a region is accumulated by two sources, migration and physical education capital, while the non-educated labor is by only migration. The paper shows that regional growth equilibrium is characterized as a saddle point. This indicates the presence of the minimum threshold size that must be overcome before a region may grow. It contrasts sharply with results obtained in regional growth models. The paper suggests that regional growth is determined less by the technical characteristics of regional production function characteristics of regional production function but by the stock combination of educated function but by the stock combination of education labor and non-educated labor. Based on this result, the impact of agglomeration economies on regional growth is explored. It is by phase diagram demonstrated that the presence of agglomeration economies do not always lead a region to growth since there still exists the minimum threshold even in the presence of agglomeration economies.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.675-687
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• 2009

In general, the forming process of the curved hull plates consists of sub tasks, such as roll bending, line heating, and triangle heating. In order to complement the automated curved hull forming system, it is necessary to develop an algorithm to classify the curved hull plates of a ship into standard shapes with respect to the techniques of forming task, such as the roll bending, the line heating, and the triangle heating. In this paper, the curved hull plates are classified by four standard shapes and the combination of them, or saddle, convex, flat, cylindrical shape, and the combination of them, that are related to the forming tasks necessary to form the shapes. In preprocessing, the Gaussian curvature and the mean curvature at the mid-point of a mesh of modeling surface by Coon's patch are calculated. Then the nearest neighbor method to classify the input plate type is applied. Tests to verify the developed algorithm with sample plates of a real ship data have been performed.

• Journal of the korean academy of Pediatric Dentistry
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• v.5 no.1
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• pp.64-75
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• 1978

In order to know cephalometric norms for the preschool children, this roentgeno cephalometric study was undertaken in each 50 Korean male and female children of primary dentition age from 4 to 5 year. The following results were obtained. 1. In the skeletal analysis, there was no significant difference between male and female in angular measurement and the linear measument of the male was generally greater than that of the female. 2. Saddle angle was $122.3^{\circ}$, articular angle was $147.6^{\circ}$, gonial angle was $119.4^{\circ}$ and the sum of each angle was $396.1^{\circ}$ in male and $396.6^{\circ}$ in female. 3. The ratio of mandibular body to anterior cranial base was about 1 : 0.91. 4. In the primary dentition, suggested that the nasion and point A move forward relative to sella turcica in a fashion, pogonion and point B are equal in angular position relative to plan S-N, bony chin and chin button was yet underdeveloped, and the forward growth of mandible was seen rapid than maxilla after 4 years. 5. Suggested that the percentage of anterior facial height to the posterior facial height were 64.4% in male and 64.1% in female. 6. Maxillary primary incisors was more upright than the permanent incisors, mandibular primary incisors was inclined lingually relative to the permanent incisor, and primary incisors was more upright than the permanent incisors. 7. Maxillary primary incisors in female was inclined labially than male. 8. In the the relationship of the upper lip and lower lip to the esthetic line, the upper lip was 2.11mm and the lower lip was 2.33mm front of the esthetic line.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.3
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• pp.186-195
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• 2010

This study has attempted to suggest a proper reinforcement method by strengthening unbonded post -tensioning through height of an anchorage hole, form of a saddle, and loading time point as parameters and evaluating the reinforcement method through a bending experiment. The result of this experiment indicated effects of reinforcement since the maximum strength ratio(the ratio of an experimental value to theoretical value) of SC composite beams before prestressed was 0.97 and after prestress were 1.00~1.21. As a result of analysis on displacement and strain, irrespective of height of an anchorage hole and loading time point, the D120-series specimen where an anchorage hole was installed on the neutral axis after reinforcement showed that its deflection continuously increased without sudden load reduction after maximum load and it stably behaved with relatively low strain of each part. In terms of reinforcement effects, the maximum strength of SCR-UD120 specimen prestressed after pre-loading was increased 1.72 times comparing to SC composite beams so SCR-UD120 specimen prestressed after pre-loading was shown to be the best.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.669-683
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• 2017

The objective of this study is to propose a modification of the previously proposed drainage system for catching the partial leakage of underground concrete structures. Two techniques were proposed for applying the drainage system only to the leaking parts. One was for conveying leaking groundwater to the collection point in the drainage system and the other was for conveying the collected groundwater to the primary drainage system of the underground concrete structure. Four waterproofing materials for conveying leaking groundwater to the catchment point of the drainage system, Durkflex made of porous rubber material, KE-45 silicone adhesive with super strong adhesion, Hotty-gel made of polymeric materials and general silicone adhesive were evaluated for waterproofing performance. Hotty-gel only showed perfect waterproof performance and the other three waterproof materials leaked. The modified drainage system with Hotty-gel and drainage pipe with fixed saddle to convey the leaking groundwater from the catchment point to the primary drainage system were tested on the concrete retaining wall. The waterproof performance and the drainage performance were evaluated by injecting 1,000 ml of water in the back of the modified drainage system at the 7-day, 14-day, 21-day, 28-day, 2-month and 3-month. There was no problem in waterproof performance and drainage performance of the modified drainage system during 3 months. In order to evaluate the construction period and construction cost of the modified drainage system, it was compared with the existing leaching repair method in surface cleaning stage, leakage treatment stage, and protective barrier stage. Total construction period and construction cost were compared in considering the contents of work, repair material, construction equipment, working time, and total number of workers. As a result of comparing and analyzing in each construction stage, it was concluded that the modified drainage system could save construction period and construction cost compared to the existing leaching repair method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1349-1353
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• 2008

Size-segregated mass and ion concentrations of atmospheric aerosols in Cheonan City were measured using a high volume air sampler equipped with a 5-stage cascade impactor and a ion chromatography between March 2006 and April 2007. The mean values of 24-hr average concentrations of TSP, PM10, PM2.5, and PM1 were 61.7, 55.2, 43.7, $33.2{\mu}g/m^3$, respectively. Mass size distributions of atmospheric aerosols were bimodal distributions with a saddle point in $1.5\;{\sim}\;3.0{\mu}m$ range in diameter separating coarse and fine particle modes. Fine particles, PM2.5 were 70.8% of the total mass of aerosols. Major ion components in aerosols were ${NH_{4}}^+$, $Na^+$, $K^+$, $Ca^{2+}$, $Mg^{2+}$ for cations, and ${SO_{4}}^{2-}$, ${NO_{3}}^-$, $Cl^-$ for anions. ion components occupied 37.4% of coarse particles and 46.2% of fine particles in mass.

• Food Science and Preservation
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• v.17 no.1
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• pp.84-90
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• 2010

We investigated methods to minimize patulin content during processing of apple juice in Korea. Ascorbic acid concentration (100, 200, 300, and 400 ppm) and activated carbon concentration (50, 100, 150, and 200 ppm) were the parameters assessed by response surface methodology. Residual patulin was lowest in the presence of 237.77 ppm ascorbic acid and 106.58 ppm activated carbon, and increased as these levels increased. Sugar content was affected more byascorbic acid concentration than by activated carbon level, and the total phenol content was revealed to be the saddle point. In addition, the expected total flavonoid content was maximized with increased levels of ascorbic acid and activated carbon. The data showed that 246-274 ppm (v/v) ascorbic acid and 93-122 ppm (v/v) activated carbon were optimal for juice extraction, and the $R^2$ quality factor for juice processing was significant and within the range of 1-10% for all tested parameters.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.514-527
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• 2005

The purposes of this study were firstly to optimize the recipe for iced cookies by cooking with five different ingredient levels of $Jinuni\;bean(X_1),\;butter(X_2)\;&\;sugar(X_3)$ and secondly to analyze the chemical and sensory test results by using RSM(Response Surface Methodology). As a result of this test, water activity decreased with increasing contents of butter or sugar, while hydrophilic browning decreased independently with increasing sugar content. There was a positive correlation(p<.001) between specific gravity and hardness, although the result was not uniform due to the interaction of each factor. There was a negative correlation(p<.001) between the spread ratio and gravity or hardness, and it tended to increase with increasing each content. Color value L and color value a had positive correlation (p<.001) and the value tended to decrease with increasing the quantity of Jinuni bean. Generally, the strength of the cookies showed a saddle point at the peak of the 3d graph. As a result of sensory evaluation, the color was sensitive to the contents of sugar and Jinuni bean, the texture was sensitive to the contents of butter and sugar, and the taste and overall quality were sensitive to all three factors. Color had a positive correlation(p<.05) with the taste, texture and overall quality. There were high positive correlations(p<.001) between the taste, texture and overall quality. The preference data showed an up-swollen, parabolic shape in the center of the 34 graph, which enabled the optimum value to be determined and the optimum mixture ratio which fulfilled all sensory items was Jinuni bean 93g, butter 188.5g and sugar 155g, indicating a substitution of flour by $44\%$.