• Proceedings of the KSME Conference
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• 2003.04a
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• pp.163-169
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• 2003

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to 30% of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.493-496
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• 2000

We study the problem of designing at minimum cost a two-connected network topology such that the shortest cycle to which each edge belongs does not exceed a given maximum number of hops. This problem is considered as part of network planning and arises in the design of backbone networks. We propose a genetic algorithm approach that uses a solution representation, in which the connectivity and ring constraints can be easily encoded. We also propose a crossover operator that ensures a generated solution is feasible. By doing so, the checking of constraints is avoided and no repair mechanism is required. We carry out experimental evaluations to investigate the solution representation issues and GA operators for the network design problem.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1130-1135
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• 2004

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Vertical roller mill is subjected to the cyclic bending stress by rollers load. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to 30% of total maintenance. Therefore, this study shows optimal design for vertical roller mill using DOE and neural network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1575-1581
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• 2005

Recently, further study is being done on the affect of crack on concrete structure and many people have made every endeavor not to leave it unsettled but to minimize it by repair works. In this paper we propose the image processing method that do not remain manual but automatically process the length, the direction and e width of cracks on concrete surface. First, we calibrate light's affect from image by using closing operation, one of morphology methods that can extract the feature of oracle and we extract the edge of crack image by sobel mask. After it, crack image is binarized by iteration binarization. And we extract the edge of cracks using noise elimination method that use an average of adjacent pixels by 3${\times}$3 mask and Glassfire Labeling algorithm. on, in this paper we propose an image processing method which can automatically measure the length, the direction and the width of cracks using the extracted edges of cracks. The results of experiment showed that the proposed method works better on the extraction of concrete cracks. Also our method showed the possibility that inspector's decision is unnecessary.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.597-603
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• 2009

Background: Atrioventricular valve regurgitation in pediatric patients with a functional single ventricles (FSV) - has been known as one of the important risk factors for death and unfavorable long-term results after a Fontan operation. We evaluated early and mid-term results of bivalvation valvuloplasty in FSV patients. Material and Method: We retrospectively evaluated 11 patients with a functional single ventricle who underwent bivalvationvalvuloplasty between 1999 and 2007. The degree of common atrioventricular valve regurgitation (CAVVR) was determined by color Doppler echocardiography (regurgitation grade scoring, trivial; 1, mild; 2, moderate; 3, severe; 4). Mean age at valve surgery was $6.9{\pm}7.0$ months (median 4 months, 24 days$\sim$21 months)and mean body weight was $6.2{\pm}2.8\;kg$ ($3.1{\sim}11.3\;kg$). Nine patients had isomerism heart and two of them had TAPVC. The concomitant procedures were performed in all but one patient. Additional commissural closure was performed in 3 patients and commissural annuloplasty in another 3 patients. Result: There was one hospital death after. surgery. A 32-day old patient who had been preoperatively dependent on a ventilator died of air way and lung problems 4.3 months after pulmonary artery banding and bivalvation valvuloplasty. Mean follow-up duration was 40 months ($4.3{\sim}114$ months). Mean preoperative CAVVR score was $3.3{\pm}0.6$, which decreased to $1.9{\pm}0.7$ postoperatively (p<0.0001). This residual regurgitation slightly increased to $2.2{\pm}0.4$ (no statistical significance) after a mean follow-up of 1.4.3 months. Six patients (60%) required re-operations for residual regurgitation at a subsequent bidirectionalcavopulmonary shunt or Fontan operation. One patient with Ebsteinoid malformation of the right sided atrioventricular valve required valve replacement due to stenoinsufficiency. Another patient required edge-to-edge repair at the right sided AV valve (between the right mural leaflet and the bridging leaflets). The remaining 4 patients required additional suture placements between bridging leaflets with or without commissural annuloplasty. All survivor had trivial or mild CAVVR at the latest follow-up. Conclusion: Bivalvation valvuloplasty for CAVVR in FSV patients is. an effective and safe procedure. However, significant numbers of the patients have small residual regurgitation and require additional valve procedures at subsequent operations. Long-term observations to monitor progression of the CAVVR is mandatory.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.70-73
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• 2001

The layup optimization by genetic algorithm (GA) for the interlaminar strength of laminated composites with free edge is presented. For the calculation of interlaminar stresses of composite laminates with free edges, extended Kantorovich method is applied. In the formulation of GA, repair strategy is adopted for the satisfaction of given constraints. In order to consider the bounded uncertainty of material properties, convex modeling is used. Results of GA optimization with scattered properties are compared with those of optimization with nominal properties. The GA combined with convex modeling can work as a practical tool for maximum interlaminar strength design of laminated composite structures, since uncertainties are always encountered in composite materials and the optimal results can be changed.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.923-924
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• 2008

Image completion is to repair a portion of removed image automatically. In this paper, we propose an image completion technique with inner structure estimation. Our method consists of two steps. An inner structure is first estimated by using sobel edge detector. Then, the removed pixels are repaired using similar patches in the known region. By experimental results, it is shown that our approach works well on natural images.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.652-657
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• 2008

A stress distribution of composite laminates patches is obtained by using the Kantorovich method when the substrate is under uniaxial load. The analysis is based on the stress function approach and uses the complementary virtual work principle. The three-dimensional stresses satisfy the traction free conditions at the free edges and the top surfaces of the patch. The stress of the bottom surfaces of the patch is obtained from equilibrium equation of patch and substrate. To demonstrate the efficiency and validity of the proposed analysis, numerical examples for cross-ply and quasi-isotropic laminates are included. The present method provides accurate stresses in the interior and near the free edges of composite laminate patches.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.105-114
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• 2018

The use of post installed anchors with bond type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post-installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with bond type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on pull-out strength of resin anchors embedded into plain concrete by pull-out experiment of resin anchors with variables such as anchor diameter, anchor interval, embedment depth and edge distance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.21-29
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• 2017

The use of post installed anchors with adhesive type has lately been increasing when it is necessary to repair, reinforce, or remodel structures. This method provides flexibility and simplicity for construction of structural members that require adhering or fixing. Meanwhile, strength evaluation of anchors with expansion type among post installed anchors systems has nearly reached setting up stage like design code through continual experimental studies for the last ten years, but analyses or experimental studies on anchor system with adhesive type are not yet sufficient. Accordingly, the designers and builders of korea depend on foreign design codes since there are no exact domestic design code they could credit. In this study, the objectives are investigating the effects on adhesive strength of anchors embedded into plain concrete by shear experiments of anchors with variables such as edge distance, anchor interval, and load direction and supplying basic data for enactment of domestic design code.