• 한국콘텐츠학회논문지
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• 제6권2호
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• pp.105-116
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• 2006

첨단 IT 기술의 발전으로 유무선 통신망을 통하여 다양한 환경에서 사용되는 대용량 디지털콘텐츠들이 급증하고 있다. 이와 함께 불시의 사고에 의한 디지털콘텐츠의 손실을 방지하기위해서 지속적인 데이터백업의 필요성이 증가하고 있다. 본 논문에서는 디지털콘텐츠의 특성을 고려하여 동일한 데이터가 중복되어 저장되는 것을 방지하기 위해 콘텐츠를 입출력 I/O크기 단위로 객체화하고, 유일한 n를 부여하여 백업장치에 저장하는 백업 시스템을 설계하고 구현한다. 제안하는 백업 시스템은 중복되어 발생하는 데이터에 대해 하나의 사본만 백업함으로써 백업되는 데이터의 양을 효과적으로 감소시켜 디지털 콘텐츠를 한정된 저장 공간에 효율적인 백업이 가능하도록 하였다.

• 대한조선학회논문집
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• 제53권1호
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• pp.10-17
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• 2016

When a planing hull straightly runs and turns, its floating position and pitch angle are changed depending on its speed, and large transient motion happens. In this paper, six degrees of freedom(6 DOF) equations of motion, which could simulate the motion of a planing hull, are established. Static and dynamic forces in vertical plane are modeled using pre-calculated displacements and metacentric heights depending on various draft, lift under bottom, and vertical damping coefficients which are used to tune the final motion. Hydrodynamic coefficients in horizontal plane at various equilibrium state are calculated by using Lewandowski's empirical formula and the speed-dependent equilibrium state are calculated beforehand by Savitsky's formula. The speed effects are considered by curve-fitting the coefficients at various speed to the polynomials. Accelerating, decelerating and backing, turning, and zig-zag are simulated and compared with the sea trial results, and it is confirmed that the speed reduction, roll, and pitch during such maneuvers of sea trial and simulation are well consistent.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.670-686
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• 2017

MapReduce (MRV1), a popular programming model, proposed by Google, has been well used to process large datasets in Hadoop, an open source cloud platform. Its new version MapReduce 2.0 (MRV2) developed along with the emerging of Yarn has achieved obvious improvement over MRV1. However, MRV2 suffers from long finishing time on certain types of jobs. Speculative Execution (SE) has been presented as an approach to the problem above by backing up those delayed jobs from low-performance machines to higher ones. In this paper, an adaptive SE strategy (ASE) is presented in Hadoop-2.6.0. Experiment results have depicted that the ASE duplicates tasks according to real-time resources usage among work nodes in a cloud. In addition, the performance of MRV2 is largely improved using the ASE strategy on job execution time and resource consumption, whether in a multi-job environment.

• 한국해양공학회지
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• 제16권2호
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• pp.53-59
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• 2002

This paper shows the experimental results controlling the height of surface and back bead in GMAW by analyzing the unexpected gaps between base metals produced in welding and by controlling welding velocity due to the variation of the gap between base metals in thin-plate welding. The back bead behavior and burn-through in I-type butt joint $CO_2$ welding of thin mild steel are analyzed in the views of short circuit time ratio and short circuit frequency. It is shown through experimental consideration that the short circuit time ratio method is more reasonable than the short circuit frequency method in analyzing the formulation of back bead under changing the gap between base metals. Based on the these results, welding manipulator is designed so as to satisfy the bead height control in real time by measuring the short circuit time ratio. To show the effectiveness of the developed bead formulation control system, the experiment is implemented under two welding conditions such as increasing gap from 0mm to 0.8mm and gradually increasing gap from 0mm to 1.2mm. The experimental results show that the bead formulation can be controlled uniformly in spite of the variation of the gap between base metals.

• Journal of information and communication convergence engineering
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• 제11권2호
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• pp.95-102
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• 2013

This paper presents a stochastic driver behavior modeling framework which takes into account both individual and general driving characteristics as one aggregate model. Patterns of individual driving styles are modeled using a Dirichlet process mixture model, as a non-parametric Bayesian approach which automatically selects the optimal number of model components to fit sparse observations of each particular driver's behavior. In addition, general or background driving patterns are also captured with a Gaussian mixture model using a reasonably large amount of development data from several drivers. By combining both probability distributions, the aggregate driver-dependent model can better emphasize driving characteristics of each particular driver, while also backing off to exploit general driving behavior in cases of unseen/unmatched parameter spaces from individual training observations. The proposed driver behavior model was employed to anticipate pedal operation behavior during car-following maneuvers involving several drivers on the road. The experimental results showed advantages of the combined model over the model adaptation approach.

• 동아시아경상학회지
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• 제9권4호
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• pp.103-111
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• 2021

Purpose - We attempt to provide a background, a review of current development of the digital technologies and their effect on the digital transformation process, and then offer our recommendations for identifying and taking strategic actions to exploit them. More importantly, we also aim to offer important recommendations for policymakers and practitioners how to better advance the innovation system by facilitating the development of digital technologies and take advantage of improvements in digital technologies. Research design, data, and methodology - This study undertakes an extensive and critical review of the digital transformation literature and identifies several important issues with relevant practical examples of best practices in the transition to digital transformation process. Results - This paper finds that digital technologies with strong technological backing have brought technological spillovers to the economy while also generating shocks. Conclusion - To maintain a healthy and developing market order, it is necessary for governments to innovate regulatory models. This study offers several important suggestions for government regulatory innovation that we believe should help to better deploy digital transformation initiatives and enhance the efficiency and effectiveness of government regulation in contributing more to the high-quality and healthy development of the digital economy.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 춘계학술발표대회
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• pp.572-575
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• 2011

It is well known that spanning tree protocol (STP) is the most commonly used protocol in switching networks for smart grid. STP selectively blocks redundancy links of the network to prevent layer 2 loops in network, and it also has a functionality of backing up links. As with the other protocols, STP has been updated with the continuing development of the network. STP is a broad concept and it does not just refer in particular to defined STP protocol in IEEE 802.1D standards, it refers to updated spanning tree protocol based on STP. Because of uneven distribution of communication traffic in root bridge, STP cannot satisfy fast converge nce while the failure occurs near the root bridge or on the root bridge in tree topologies of STP. In this paper, we propose a novel method --- Hyper Cube Spanning Tree Protocol (HCSTP) to solve uneven distribution of communication traffic. Theoretically, hyper cube in our protocol increases throughput and improves the utilization of communication. The simulation results show that HCSTP can achieve comparative and considerably higher performance than other STP protocols in terms of reconnection.

• 헤리티지:역사와 과학
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• 제56권2호
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• pp.100-121
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• 2023

본 논문은 조선 후기 설립된 영희전 감실 및 이안소의 공간 구성과 이곳에 사용된 오봉산병풍의 특징을 고찰하였다. 이 과정에서 18세기 중엽 태조진전이 영희전의 예를 따라 오봉산병풍을 배설한 내용과 18세기 이전 태조진전의 감실 모습을 확인할 수 있었으며 영희전 감실 구성의 연원도 살펴보았다. 영희전 감실은 태조진전 및 선원전과 달리, 당가 없이 온돌바닥 위로 난간이 달린 평상 형태를 한 대형의 용상을 놓았다. 이 용상 위로 4첩 오봉산병풍을 가운데 2첩은 뒤로 펴고 좌우 각 1첩은 나누어 펴 '⊓' 형태로 배설하였다. 난간을 단 평상 위로 첩병풍을 펼치는 배설 방식은 영희전 감실 조성 당시 태조진전이 아닌, 빈전 영침의 구성을 참조했을 가능성을 시사했다. 한편, 어진의 이안 시에는 용상보다 규모와 장식을 간략하게 한 난간평상을 사용했다. 이안소에는 감실과 같이 4첩 오봉산병풍을 '⊓' 형태로 설치했으나 평상 위에 올리지 않고 뒤편에서 난간평상을 감싼 형태로 펼친 후 어진을 봉안한 흑장궤를 그 위에 올렸다. 이 같은 배설 방식이 반영된 감실과 이안 소용 오봉산병풍은 모두 대형의 4첩 왜장 병풍으로 가운데 두 폭이 넓고 좌우로 접어 펴는 1·4폭이 좁은 형태였다. 장황은 별도의 하회장 없이 병풍 가장자리를 따라 회장을 둘렀다. 감실과 이안 소용 오봉산병풍은 장황과 배접 등의 재료에 일부 차이를 두어 배설 장소의 위상을 반영하였다. 문헌 기록에 대한 고찰을 통해 근현대기를 거치며 본래의 이력과 기능을 잃은 채 전하는 병풍 중 국립고궁박물관 소장 <일월오봉도>와 <인정전오봉산병풍>이 영희전 병풍임을 추정할 수 있었다. 두 병풍은 배설 방식을 고려해 세 개의 봉우리와 해·달 등을 가운데 2·3폭에 대칭으로 배치하고 나머지 두 봉우리와 적송을 1·4폭에 그렸다. 한편, <인정전 오봉산병풍>은 병풍틀의 배접지로 1840년 답안 일부를 포함한 감시낙폭지를 사용해, 1858년 영희전 증건 시 향후 순조어진의 이안을 대비해 만든 이안청 병풍으로 추정되었다.

• 대한기계학회논문집A
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• 제28권12호
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• pp.1958-1967
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• 2004

This paper describes the method to rapidly fabricate the large-sized physical model with the envelope model size of more than 600 mm${\times}$ 600 mm${\times}$ 600 mm using two type semi-automatic VLM-ST processes in connection with the reverse engineering technology. The fabrication procedure of the large-sized solid shape is as follows: (1) Generation of STL data from 3D scan data using 3D scanner, (2) generation of shell-type STL data by Boolean operation, (3) division of shell-type STL data into several pieces by solid splitting, (4) generation of USL data for each piece with VLM-Slicer, (5) fabrication of each piece by cutting and stacking according to USL data using VLM-ST apparatus, (6) completion of a shell-type prototype by zigzag stacking and assembly for each piece, (7) completion of a 3D solid shape by foam backing, (8) surface finish of a completed 3D solid shape by coating and sanding. In order to examine the applicability of the proposed method, the miniature of the Mount Rushmore Memorial has been fabricated. The envelope model size of the miniature of the Mount Rushmore Memorial is 1,453 mm${\times}$ 760 mm${\times}$ 853 mm in size. From the result of the fabricated miniature of the Mount Rushmore Memorial, it has been shown that the method to fabricate the large object using two type semi-automatic VLM-ST processes in connection with the reverse engineering technology are very fast and efficient.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1516-1519
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• 1997

With disseminationof Distributed Control Systems(DCS), the huge amounts of process operation data could have been available and led to figure out process behaviors better on the statistical basis. Until now, the statistical modeling technology has been susally applied to process monitoring and fault diagnosis. however, it has been also thought that these process information, extracted from statistical analysis, might serve a great opportunity for process operation improvements and process improvements. This paper proposed a general methodolgy for process operation improvements including data analysis, backing up the result of analysis based on the methodology, and the mapping physical physical phenomena to the Principal Components(PC) which is the most distinguished feature in the methodology form traditional statistical analyses. The application of the proposed methodology to the Balst Furnace(BF) process has been presented for details. The BF process is one of the complicated processes, due to the highly nonlinear and correlated behaviors, and so the analysis for the process based on the mathematical modeling has been very difficult. So the statisitical analysis has come forward as a alternative way for the useful analysis. Using the proposed methodology, we could interpret the complicated process, the BF, better than any other mathematical methods and find the direction for process operation improvement. The direction of process operationimprovement, in the BF case, is to increase the fludization and the permeability, while decreasing the effect of tapping operation. These guide directions, with those physical meanings, could save fuel cost and process operator's pressure for proper actions, the better set point changes, in addition to the assistance with the better knowledge of the process. Open to set point change, the BF has a variety of steady state modes. In usual almost chemical processes are under the same situation with the BF in the point of multimode steady states. The proposed methodology focused on the application to the multimode steady state process such as the BF, consequently can be applied to any chemical processes set point changing whether operator intervened or not.