• Journal of Information Processing Systems
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• v.17 no.2
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• pp.242-252
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• 2021

Following the intuition that the local information in time instances is hardly incorporated into the posterior sequence in long short-term memory (LSTM), this paper proposes an attention augmented mechanism for fault diagnosis of the complex chemical process data. Unlike conventional fault diagnosis and classification methods, an attention mechanism layer architecture is introduced to detect and focus on local temporal information. The augmented deep network results preserve each local instance's importance and contribution and allow the interpretable feature representation and classification simultaneously. The comprehensive comparative analyses demonstrate that the developed model has a high-quality fault classification rate of 95.49%, on average. The results are comparable to those obtained using various other techniques for the Tennessee Eastman benchmark process.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.481-493
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• 2021

Regional brands are recognized for their importance as one of the local public relations policies, but only the methods promoted by local government officials and outside experts are revealing limitations in self-reliance and sustainability. In order for a regional brand to succeed, it is necessary to develop and manage a brand that fits the characteristics of the region together with various stakeholders including residents. In this study, it was confirmed that regional brand evaluation indicators may vary depending on the stage of co-creation in the design process for regional brand development, and the type of value co-creation was determined through a classification method using the results of the evaluation index. According to the results of the study, the type of value co-creation that fits the local situation and characteristics can be derived by adjusting the stage of co-creation execution in the design process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.130-135
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• 2008

An aerodynamic optimization design process of multistage axial turbine is presented in this article: first, applying quasi-three dimensional(Q3D) design methods to conduct preliminary design and then adopting modern optimization design methods to implement multistage local optimization. Quasi-three dimensional(Q3D) design methods, which mainly refer to S2 flow surface direct problem calculation, adopt the S2 flow surface direct problem calculation program of Harbin Institute of Technology. Multistage local optimization adopts the software of Numeca/Design3D, which jointly adopts genetic algorithm and artificial neural network. The major principle of the methodology is that the successive design evaluation is performed by using an artificial neural network instead of a flow solver and the genetic algorithms may be used in an efficient way. Flow computation applies three-dimensional viscosity Navier Stokes(N-S) equation solver. Such optimization process has three features: (i) local optimization based on aerodynamic performance of every cascade; (ii) several times of optimizations being performed to every cascade; and (iii) alternate use of coarse grid and fine grid. Such process was applied to optimize a three-stage axial turbine. During the optimization, blade shape and meridional channel were respectively optimized. Through optimization, the total efficiency increased 1.3% and total power increased 2.4% while total flow rate only slightly changed. Therefore, the total performance was improved and the design objective was achieved. The preliminary design makes use of quasi-three dimensional(Q3D) design methods to achieve most reasonable parameter distribution so as to preliminarily enhance total performance. Then total performance will be further improved by adopting multistage local optimization design. Thus the design objective will be successfully achieved without huge expenditure of manpower and calculation time. Therefore, such optimization design process may be efficiently applied to the aerodynamic design optimization of multistage axial turbine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.301-306
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• 2009

High strength steels are widely used for lightweight automobile parts and the control of springback is very important in sheet metal forming. The object of this study is to develop the forming process for stair type side sill made of high strength steel, DP780. Stair type side sill with local formed area and geometry change area can improve stiffness and design freedom but there are a few studies for forming process. The forming technology considered in this paper is form type process, which have many advantages for farming of high strength steel compared with draw type process. Finite element analysis is carried out to predict formability and springback. It is shown that angle calibration of die is essential for reducing springback, and local forming involving bead is effective to control springback also. The effectiveness of local forming and angle calibration is verified by experimental.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1451-1469
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• 2019

This paper proposes a residual stress mitigation of a nuclear safety-related austenitic stainless steel TP304 pipe bended by local induction heating process via performing elastic-plastic finite element analysis. Residual stress distributions of the pipe bend were calculated by performing finite element analysis. Validity of the finite element analysis procedure was verified via comparing with temperature histories measured by using thermocouples, ultrasonic thickness measurement results, and residual stress measurement results by a hole-drilling method. Parametric finite element stress analysis was performed to investigate effects of the process and geometric shape variables on the residual stresses on inner surfaces of the pipe by applying the verified procedure. As a result of the parametric analysis, it was found that it is difficult to considerably reduce the inner surface residual stresses by changing the existing process and geometric shape variables. So, in order to mitigate the residual stresses, effect of an additional process such as cooling after the bending on the residual stresses was investigated. Finally, it was identified that the additional heating after the bending can significantly reduce the residual stresses while other variables have insignificant effect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.536-564
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• 2019

Soft faults are inherent in wireless sensor networks (WSNs) due to external and internal errors. The failure of processes in a protocol stack are caused by errors on various layers. In this work, impact of errors and channel misbehavior on process execution is investigated to provide an error classification mechanism. Considering implementation of WSN protocol stack, inter-process correlations of stacked and peer layer processes are modeled. The proposed model is realized through local and global decision trees for fault diagnosis. A hybrid framework is proposed to implement local decision tree on sensor nodes and global decision tree on diagnostic cluster head. Local decision tree is employed to diagnose critical failures due to errors in stacked processes at node level. Global decision tree, diagnoses critical failures due to errors in peer layer processes at network level. The proposed model has been analyzed using fault tree analysis. The framework implementation has been done in Castalia. Simulation results validate the inter-process correlation model-based fault diagnosis. The hybrid framework distributes processing load on sensor nodes and diagnostic cluster head in a decentralized way, reducing communication overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1106-1111
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• 2002

This paper presents a new watermarking scheme to reduce the detection error probability through removal of local mean values of an original signal equivalently. At first, we show that the error probability is reduced by the removal of the local mean values. In the removal process, we are in need of a method that equivalently removes the local mean values without modification of the original signal since the process changes the original signal. The method is based on the principle that as the watermark with zero local mean values is embedded, the local mean values of the original signal is equivalently removed in detection of the watermark. The principle are analytically proven, and the superiority of the proposed method is verified by experiments for variety of watermarks.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.112-117
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• 2000

A numerical study on natural convection in a vertical square cavity filled with a porous medium is carried out with Brinkman-Forchheimer-extended Darcy flow model, and the validity of local thermodynamic equilibrium assumption is studied. The local thermodynamic equilibrium refers to the state in which a single temperature can be used to describe a heat transfer process in a multiphase system. With this assumption, the analysis is greatly simplified because only one equation is needed to describe the heat transfer process. But prior to using this assumption, it is necessary to know in what conditions the assumption can be used. The numerical results of this study reveal that large temperature difference between fluid phase and solid phase exists near wall region, paticularily when the convection becomes dominant over conduction. And the influence of flow parameters such as fluid Rayleigh number, fluid Prandtl number, dimensionless particle diameter and conductivity ratio are investigated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.407-410
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• 2002

Optical fiber is a kind of local loop types. Local loop unbundling(LLU) has been understood as a way to facilitate competition in the access and local telephone service markets. Major countries such as US, Germany, Canada and UK are currently implementing LLU and many other countries are considering its introduction. The purpose of this paper is to review the opening process of optical fiber network in major countries, and to discuss the implication of case study.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.5
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• pp.139-150
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• 2018

This paper aims to elaborate the role and availability of the community enterprise as a form of methodology in local regeneration, dealing with urban social problems generated in the process of urban development. In a situation of the increasing skepticism in the capitalism, the instability in public welfare system and disintegration of community, social economy has come to the fore as an alternative. The community enterprise, especially, has shown the potential to form a virtuous cycle in local regeneration system; residents recognize local problems by themselves; discover and utilize the local resources and assets in the process of solving the problems as an entrepreneurial form; and consequently create social and economic capital which can be reinvested in the local community. Given these aspects, Korean government has implemented supporting policies for the promotion of community enterprises, and new government's "Urban Regeneration New Deal Project" are putting more importance on the role of social and community enterprises as a propulsion unit. In this regard, this paper first explores the concept and features of community enterprise in economic and social aspects, whereby it analyzes the capacity of community enterprises as principal agencies or implements in local development. Then, the development status and institutional supports for community enterprises in the UK is revealed, and investigates case studies which are playing a revolutionary role in urban regeneration or local economic revitalization. Based on this analysis, it draws the main factors for the sustainable and autogenous community enterprise as follows: flexibility in legal forms, community owned assets, diverse fund streams and invigorating social investment market, active partnership between public and private sectors, ardent enterprisers and intermediate support organizations.