• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.131-134
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• 2020

스마트시티로 가는 첫걸음이자 핵심이라 할 수 있는 IoT 기술이 우리의 삶을 변화시키고 있다. 원격에서 집 내부의 상태를 확인하며 조정할 수 있고, 집 내부의 상황도 영상을 통해 확인할 수 있게 되었다. 이처럼 IoT 기술은 우리 삶의 편리함을 제공하고 중요한 요소가 되었지만, IoT 환경 관리의 주체가 사용자 개인이거나 IoT 환경상태를 모니터링하며 관리할 수 있는 수단이 없어 관리가 되지 않고 있고 공격을 받아도 사용자가 알 수 없다는 특성 때문에 IoT 보안에 있어 심각한 문제를 일으킬 수 있다. 이러한 문제에도 불구하고 IoT 보안에 대한 인식과 IoT 환경에 특화된 관리 시스템은 갖춰지지 않고 있다. 본 논문에서는 오픈 소스 데이터 분석 및 시각화 솔루션인 Elastic Stack을 활용하여 손쉽게 IoT 환경을 관리하고 상태를 시각화하여 제공하는 IoT 환경 관리 시스템을 제안한다.

• Transactions of Materials Processing
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• v.26 no.4
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• pp.228-233
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• 2017

In flat rolling mills, demands for precise process set-up and control are increasing than ever before. Consequently, it is imperative to establish a novel approach, which would provide valuable information regarding the detailed aspects of deformation behavior of the strip, and rolls during rolling. In this paper, we present a finite element (FE) approach for 3-D coupled analysis of the elastic-plastic deformation of the strip and the elastic deformation of rolls in the roll-stack of a mill stand.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.77-85
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• 2016

This study was conducted to solve the problem such as damage of completed compaction ground using the conventional compaction control method. In this study, a TDR system equipped with a flat type probe has been developed. Also, the Piezoelectric stack, which is an instrument for measuring the elastic wave on the ground, has been added to the developed flat type probe. In this study, the strength variation of reinforced soil with time was determined by using the TDR system. The value of compression and shear modulus increased from 198.65MPa to 541.80MPa and from 125.55MPa to 302.02MPa with time, respectively. Based on the test results, it has been confirmed that the developed TDR system can be used as reinforced effect analysis of soil and compaction control.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.97-100
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• 2007

Fuel Cell Stack performance, which is influenced by the maintenance of a constant internal environment, requires high levels of air tightness. Used for analysis, gasket for fuel cell is made of elastic rubber materials and placed over separator, and shape of deformation of a gasket affects the transformation separator and airtightness while fastening structure. Separator as made of steel sheet isn't broken under pressure but can affect gas and cool water flow by the plastic deformation process. Therefore， it is understood that assembly process is well developed in case distribution of stress and shape of deformation is shown uniformly. This study is conducted on the assumption that a fuel cell maintenance is advantageous in that conditions. In this paper, analyses of unit cell and partial model were performed and distribution of stress and shape of deformation of Gasket and separator were analyzed to evaluate the airtightness while fastening structure.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.562-577
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• 2014

A reliable steady/transient hydro-elastic analysis is developed for flexible (composite) marine propeller blade design which deforms according to its environmental load (ship speed, revolution speed, wake distribution, etc.) Hydro-elastic analysis based on CFD and FEM has been widely used in the engineering field because of its accurate results however it takes large computation time to apply early propeller design stage. Therefore the analysis based on a boundary element method-Finite Element Method (BEM-FEM) Fluid-Structure Interaction (FSI) is introduced for computational efficiency and accuracy. The steady FSI analysis, and its application to reverse engineering, is designed for use regarding optimum geometry and ply stack design. A time domain two-way coupled transient FSI analysis is developed by considering the hydrodynamic damping ffects of added mass due to fluid around the propeller blade. The analysis makes possible to evaluate blade strength and also enable to do risk assessment by estimating the change in performance and the deformation depending on blade position in the ship's wake. To validate this hydro-elastic analysis methodology, published model test results of P5479 and P5475 are applied to verify the steady and the transient FSI analysis, respectively. As the results, the proposed steady and unsteady analysis methodology gives sufficient accuracy to apply flexible marine propeller design.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.115-130
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• 2015

Extended elastic impedance (EEI) is an extension of elastic impedance (EI) which is a generalization of acoustic impedance (AI) for nonzero angles of incidence and can be tuned to be proportional to reservoir properties. In this study, we evaluated EEI inversion by estimating the P-($V_p$) and S-wave velocities ($V_s$), P-wave to S-wave velocity ratio ($V_p/V_s$), and Poisson's ratio of the Second Wall Creek Sand of the Teapot Dome field, Wyoming, USA. We also applied the EEI inversion technique to estimate porosity, gamma-ray values, and density of the Second Wall Creek Sand. Data used in the study include 3-D pre-stack seismic data from the southern part of the field and four wells, selected from a large well database. The $V_s$ logs at the wells were constructed from the $V_p$ logs using the empirical relationships. The percent prediction errors for the four velocity properties are less than about 5% except for Poisson's ratio at one well, supporting that the EEI inversion can be used in the prediction of rock properties. However, the results from the EEI inversion analysis of porosity, gamma-ray values, and density at the wells were unsatisfactory and thus these properties, which are not directly computed from velocities, may not be suitable for EEI inversion.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.198-201
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• 1999

An automated storage and retrieval machinery for high rack warehouse systems is developed in order to stack the various kinds of productions. However, according to increase in the rack height, the long lead time should be taken. In stacker crane systems, the variations of the lifting height and the load generate the vibration of lifting machine, and it makes a Position control to be difficult Therefore, the reduction of vibration will be important factor for saving the lead time and the damage of Productions. This paper deals with a position control of stacker crane in automated high rack warehouse system by using a gain-scheduled control algorithm via a LMI method, where the variations of elastic coefficient of the stacker crane's post are considered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.503-509
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• 2019

The demand for smaller, faster, and multi-functional mobile devices in increasing at a rapidly increasing rate. In response to these trends, Stacked Chip Scale Package (SCSP) is used widely in the assembly industry. A film type adhesive called die attach film (DAF) is used widely for bonding chips in SCSP. The DAF requires high flowability at high die attachment temperatures for bonding chips on organic substrates, where the DAF needs to feel the gap depth, or for bonding the same sized dies, where the DAF needs to penetrate bonding wires. In this study, the mixture design of experiment (DOE) was performed for three raw materials to obtain the optimized DAF recipe for low elastic modulus at high temperature. Three components are acrylic polymer (SG-P3) and two solid epoxy resins (YD011 and YDCN500-1P) with different softening points. According to the DOE results, the elastic modulus at high temperature was influenced greatly by SG-P3. The elastic modulus at $100^{\circ}C$ decreased from 1.0 MPa to 0.2 MPa as the amount of SG-P3 was decreased by 20%. In contrast, the elastic modulus at room temperature was dominated by YD011, an epoxy with a higher softening point. The optimized DAF recipe showed approximately 98.4% pickup performance when a UV dicing tape was used. A DAF crack that occurred in curing was effectively suppressed through optimization of the cure accelerator amount and two-step cure schedule. The imizadole type accelerator showed better performance than the amine type accelerator.

• Transactions of Materials Processing
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• v.23 no.3
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• pp.171-177
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• 2014

The current collector for the molten carbonate fuel cell (MCFC) which has sheared protrusions is manufactured by the three-stage forming process that integrates slitting, preforming and final forming. Due to the repetition of sheared protrusions, an effective simulation method is required to predict the mechanical behavior. In the current study, a sheet with sheared protrusions was assumed to be an orthotropic plate, which has the same length, width and height. FEM simulations were conducted to evaluate the homogenized properties of the current collector, which has 4 (longitudinal direction) x 4 (transverse direction) sheared protrusions. The simulation model was constructed using hexahedral mesh coarsening. From the verification examples, it was found that the proposed simulation method was efficient within reasonable accuracy. The calculated homogenized properties can be applied to the design of a stack for molten carbonate fuel cells and the prediction of mechanical behavior for other applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.749-766
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• 2021

Cyber powers around the world are conducting cyber information-gathering activities in cyberspace, a global domain within the Internet-based information environment. Accordingly, it is imperative to obtain the latest information through the cyber intelligence preparation of the battlefield (IPB) process to prepare for future cyber operations. Research utilizing the cyber battlefield visualization method for effective cyber IPB and situation awareness aims to minimize uncertainty in the cyber battlefield and enable command control and determination by commanders. This paper designed architecture by classifying cyberspace into a physical, logical network layer and cyber persona layer to visualize the cyber battlefield using BGP archive data, which is comprised of BGP connection information data of routers around the world. To implement the architecture, BGP archive data was analyzed and pre-processed, and cyberspace was implemented in the form of a Di-Graph. Information products that can be obtained through visualization were classified for each layer of the cyberspace, and a visualization method was proposed for performing cyber IPB. Through this, we analyzed actual North Korea's BGP and OSINT data to implement North Korea's cyber battlefield centered on the Internet network in the form of a prototype. In the future, we will implement a prototype architecture based on Elastic Stack.