• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.534-539
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• 2009

Reaction Bonded Silicon Carbide(RBSC) has been used for engineering ceramics due to low-temperature fabrication and near-net shape products with excellent structural properties such as thermal shock resistance, corrosion resistance and mechanical strength. Recently, attempts have been made to develop hot gas filter with gradient pore structure by RBSC to overcome weakness of commercial clay-bonded SiC filter such as low fracture toughness and low reliability. In this study a fabrication process of porous RBSC with multi-layer pore structure with gradient pore size was developed. The support layer of the RBSC with multi-layer pore structure was fabricated by conventional Si infiltration process. The intermediate and filter layers consisted of phenolic resin and fine SiC powder were prepared by dip-coating of the support RBSC in slurry of SiC and phenol resin. The temperature of $1550^{\circ}C$ to make Si left in RBSC support layer infiltrate into dip-coated layer to produce SiC by reacting with pyro-carbon from phenol resin.

• Journal of Conservation Science
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• v.34 no.6
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• pp.557-568
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• 2018

The manufacturing techniques were studied by investigating a precise analysis on wall structure, features of materials and the painting layer of the bracket mural paintings at Daeungbojeon Hall in Naesosa temple. The wall frame is a single-branch structure, and The mural paintings are composed of 3 layers which are a support layer, a finishing layer and a painting layer. The support layer and the finishing layer are an earth wall that sand and clay such as Quartz, Feldspar, and etc. are mixed. The support and the finishing layers have a combination of medium particle sand and smaller than fine particle sand in the approximate ratios of 0.8:9.2 and 6:4, respectively. Therefore, the aforementioned ratio of sand with medium or large particles is relatively higher in the finishing layer than the support layer. As a result of a precise analysis on the painting layer, it has a relatively thick ground layer for painting which is maximum $456.15{\mu}m$ by using Celadonite or Glauconite and the paintings were colored by using pigments such as Atacamite, Kaolinite or Halloysite, Oxidized steel, and etc. on it. The manufacturing style and the painting techniques of an earth wall are included in the category of the Joseon Dynasty style that have been studied up to now, but the facts that the finishing layer has a high content of sand and a middle layer and chopped straw have not been identified. These are remarkable points in terms of structure and materials, and can be crucial in the evaluation of the state of conservation of mural paintings or preparation of a conservation plan.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.57-65
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• 2010

Recently, the character recognization technique is strongly needed to enable the mobile communication devices with cameras to gather input information from the users. In general, it is not easy to reuse a CBOCR(Camera Based Optical Character Recognizer) module because of its dependency on a specific platform. In this paper, we propose a software architecture for CBOCR module providing the easy adaptability to various mobile communication platforms. The proposed architecture is composed of the platform dependency support layer, the interface layer, the engine support layer, and the engine layer. The engine layer adopts a plug-in data structure to support various hardware endian policies. We show the effectiveness of the proposed method by applying the architecture to a practical product.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.233-243
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• 2021

Rib spalling is a major issue affecting the safety of steeply inclined coal seam. And the failure coal face and support system can be affected with each other to generate a vicious cycle along with inducing large-scale collapse of surrounding rock in steeply inclined coal seam. In order to analyze failure mechanism and propose the corresponding prominent control measures of steeply inclined coal working face, mechanical model based on coal face-support-roof system and mechanical model of coal face failure was established to reveal the disaster mechanism of rib spalling and the sensitive analysis of related factors was performed. Furthermore, taking 3402 working face of Chen-man-zhuang coal mine as engineering background, numerical model by using FLAC3D was built to illustrate the propagation of displacement and stress fields in steeply inclined coal seam and verify the theory analysis as mentioned in this study. The results show that the coal face slide body in steeply inclined working face can be observed as the failure height of upper layer smaller than that of lower layer exhibiting with an irregular quadrilateral pyramid shape. Moreover, the cracks were originated from the upper layer of sliding body and gradually developed to the lower layer causing the final rib spalling. The influence factors on the stability of coal face can be ranked as overlying strata pressure (P) > mechanical parameters of coal body (e.g., cohesion (c), internal fraction angle (φ)) > support strength (F) > the support force of protecting piece (F') > the false angle of working face (Θ). Moreover, the corresponding control measures to maintain the stability of the coal face in the steeply inclined working face were proposed.

• The Journal of Korean Institute of Information Technology
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• v.15 no.12
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• pp.165-171
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• 2017

This paper proposes a method of support-generation using morphological image processing instead of geometric calculations. The geometric computational cost is dependent on the shape, but our method is independent on the shape. For obtaining the external support area for extrusion shape, we represents morphological operations between two sliced layer images and shows results of each operation stages. Internal support area is evaluated from erosion and opening operations with the sliced-layer image. In these support areas, the supporter image is generated using the designed support structures. Also, we made a DLP printer and the STL model included supporter-structure is printed by the DLP printer. We confirmed the necessity of support-generation method with the support structures individually dependent on materials by looking at the printed results.

• ETRI Journal
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• v.35 no.6
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• pp.990-1000
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• 2013

This paper describes the scalable extension of High Efficiency Video Coding (HEVC) to provide flexible high-quality digital video content services. The proposed scalable codec is designed on multi-loop decoding architecture to support inter-layer sample prediction and inter-layer motion parameter prediction. Inter-layer sample prediction is enabled by inserting the reconstructed picture of the reference layer (RL) into the decoded picture buffer of the enhancement layer (EL). To reduce the motion parameter redundancies between layers, the motion parameter of the RL is used as one of the candidates in merge mode and motion vector prediction in the EL. The proposed scalable extension can support scalabilities with minimum changes to the HEVC and provide average Bj${\o}$ntegaard delta bitrate gains of about 24% for spatial scalability and of about 21% for SNR scalability compared to simulcast coding with HEVC.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.827-833
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• 2016

In this paper, we propose a deep least squares support vector machine (LS-SVM) for regression problems, which consists of the input layer and the hidden layer. In the hidden layer, LS-SVMs are trained with the original input variables and the perturbed responses. For the final output, the main LS-SVM is trained with the outputs from LS-SVMs of the hidden layer as input variables and the original responses. In contrast to the multilayer neural network (MNN), LS-SVMs in the deep LS-SVM are trained to minimize the penalized objective function. Thus, the learning dynamics of the deep LS-SVM are entirely different from MNN in which all weights and biases are trained to minimize one final error function. When compared to MNN approaches, the deep LS-SVM does not make use of any combination weights, but trains all LS-SVMs in the architecture. Experimental results from real datasets illustrate that the deep LS-SVM significantly outperforms state of the art machine learning methods on regression problems.

• Smart Structures and Systems
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• v.13 no.3
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• pp.453-471
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• 2014

The fault diagnosis of rolling element bearings has drawn considerable research attention in recent years because these fundamental elements frequently suffer failures that could result in unexpected machine breakdowns. Artificial intelligence algorithms such as artificial neural networks (ANNs) and support vector machines (SVMs) have been widely investigated to identify various faults. However, as the useful life of a bearing deteriorates, identifying early bearing faults and evaluating their sizes of development are necessary for timely maintenance actions to prevent accidents. This study proposes a new two-layer structure consisting of support vector regression machines (SVRMs) to recognize bearing fault patterns and track the fault sizes. The statistical parameters used to track the fault evolutions are first extracted to condense original vibration signals into a few compact features. The extracted features are then used to train the proposed two-layer SVRMs structure. Once these parameters of the proposed two-layer SVRMs structure are determined, the features extracted from other vibration signals can be used to predict the unknown bearing health conditions. The effectiveness of the proposed method is validated by experimental datasets collected from a test rig. The results demonstrate that the proposed method is highly accurate in differentiating between fault patterns and determining their fault severities. Further, comparisons are performed to show that the proposed method is better than some existing methods.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.67-74
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• 2010

Single layer latticed domes which have a mechanics property, a functional property, a aesthetic property and so on, occupies one part of long span space structures and after this, the using parts will be extended. The frame network pattern of single-layer latticed domes can be infinitely taken into account. The typical network patterns are triangular, square, hexagon, lamella and rib etc. It would take long time and cost too much to erect large roof structures with traditional erection techniques due to require of large number of temporary bracing and supports. The erection of large roof structures requires special techniques. As one of these special techniques is the Step-Up election method that utilizes jack-up supports and this will extremely saves time and cost to erect large roof structures. The objective of this study is to analysis the buckling characteristics of single-layer lamella domes according to the support number and position. From the result of this study, we obtained the fundamental data for the structural engineers who design the temporary support of large roof structures.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.393-404
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• 2004

Recently, mSCTP (Mobile SCTP) has been proposed as a transport layer approach for supporting mobility. mSCTP is based on the ‘multi-homing’ feature of Stream Control Transmission Protocol(SCTP), and utilize the functions to dynamically add or delete IP addresses of end points to or from the existing connectionin order to support mobility. In this paper, we propose a mechanism to determine when to add or delete an W address, utilizing the link layer radio signal strength information in order to enhance the performance of mSCTP We also propose a mechanism for a mobile node to initiate the change of data delivery path based on link layer radio signal strength information. In addition, if it takes long time to acquire new data path, we propose an approach for reducing handover latency. The simulation results show that the performance of proposed transport layer mobility support mechanism is competitive compared to the traditional network layer mobility supporting approach. Especially, when the moving speed of mobile node is fast, it shows better performance than the traditional network layer approaches.