• 방송공학회논문지
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• 제24권1호
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• pp.132-141
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• 2019

매우 제한된 전송 대역을 이용하여 비디오 데이터를 전송해야 하는 필요성은, 광대역을 통한 비디오 서비스가 활성화되어 있는 현 시점에서도 꾸준히 존재한다. 본 논문에서는 초협대역 네트워크를 통한 저해상도 비디오 전송을 위해, 공간 확장형 스케일러블 비디오 코딩 프레임워크에서 기본 계층의 부호화된 프레임을 심층 신경망 기반 초해상화 기법을 이용하여 업스케일링 하여 향상 계층 부호화 시에 예측 영상으로 활용하여 부호화 효율을 높이는 방법을 제안한다. 기존의 스케일러블 HEVC (High efficiency video coding) 표준에서는 고정된 필터로 업스케일링을 하는데 비해, 본 논문에서는 초해상화 수행을 위해 학습된 심층신경망을 기존의 고정 업스케일링 필터를 대체하여 적용하는 스케일러블 비디오 코딩 프레임워크를 제안한다. 이를 위해 스킵 연결과 잔차 학습 기법 등이 적용된 심층 콘볼루션 신경망 구조를 제안하고, 비디오 코딩 프레임워크의 실제 응용 상황에 맞추어 학습시켰다. 입력 해상도가 $352{\times}288$이고 프레임율이 8fps인 영상을 110kbps로 부호화 하는 응용 상황에서, 기존의 스케일러블 HEVC 프레임워크에 비해 제안하는 스케일러블 비디오 코딩 프레임워크의 화질이 더 높고 부호화 효율이 우수함을 확인할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제41권1호
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• pp.21-30
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• 2017

현재 국내에서 공장 보수용접이 가장 많이 이루어지고 있는 선박 엔진 부품은 피스톤 크라운과 배기밸브이다. 또한 선박 엔진 밸브와 크랭크 축 등의 경우에는 신규 부품에서도 성능향상을 위해 표면개질방법으로 오버레이 용접이 시공되고 있다. 용착률을 높이는 고능률 오버레이 용접 공정으로 Hot Wire GTAW, Cold Tandem GMAW, Band Arc SAW, Tandem SAW법이 개발되어 있고, 용사방법으로 PTA공정이 현장에서 많이 시공되고 있다. 입열량 제어가 용이한 공정으로 GMAW-Pulse, CMT 용접공정이 있다. 엔진 배기밸브의 보수를 위한 오버레이공정에서 열영향부에 가까운 모재 내에 액화균열이 발생하는 경우가 있어 주의를 요한다. GMAW-Pulse 공정과 CMT공정에서는 입열량 제어가 용이하여 높은 용착속도를 유지하면서도 액화균열의 발생 없이 엔진 밸브의 보수 또는 표면 개질 목적으로 시공이 가능하다. 최근에 국내에서 고능률 용접 공정으로 선박엔진의 보수 또는 표면 개질 목적으로 사용 가능한 Super-TIG 용접공정이 개발되어 있다. 이 공정은 아크를 플라즈마 스트림이라고 보고 전류증가에 따라 커지는 아크압력을 막으면서도 용가재의 용융 효율이 극대화 되도록 폭이 큰 C형의 오목한 용가재를 발명하여 용착률을 획기적으로 향상시킨 용접공정이다.

• 한국수산과학회지
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• 제20권2호
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• pp.114-118
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• 1987

단순만곡형과 Super-V형 전개판의 성능을 비교하기 위하여 모형실험을 실시하였다. 모형전개판은 두께 1mm되는 철판으로써 제작하였으며, 단순만곡형은 만곡도 $12\%$, 평면투영면적 $432cm^2$되게, Super V형은 횡단면의 양곡도가 어디서나 $12\%$되고 평면 투영면적은 $436cm^2$되게 하였다. 실험은 측정의 결과, 단순만곡형은 최대 유교진행각도가 $25^{\circ}$이고, 그 때의 전개력계수는 1.47, 항력계수는 0.42이며, Super-V형은 그것이 각각 $20^{\circ},\;1.40,\;0.40$으로서 유체역학적성능은 단순만곡형이 다소 우수하다고 판단된다.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.9-16
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• 2013

The comparisons of performance characteristics between the super-mirror face grinding machine using variable air pressure developed in this laboratory to grind precisely the sliding face of a surface hardened workpiece with thermal spray and the conventional one are investigated by measuring the surface roughness and hardness for a SCM440. To process variously workpiece according to shape, size and materials, the rotating and contacting forces of the developed grinding machine can be changed by air pressure. The surface roughness of processed workpiece can be also attained to state of mirror face by grinding precisely the sliding face with changing the rotating speed of diamond wheel. It is possible to be attached to the various machine tools because the super-mirror face grinding machine using variable air pressure is a small size. The grinding efficiency is elevated because it can be worked by two or more grinding machines attached to concurrently a machine tool for the large workpiece. In this study, results show that the cusp height of the super-mirror face grinding machine for the particle size of 100 and $1500No./mm^2$ is lower than that of the conventional one because the vibration is reduced by rotating very fast the diamond wheel with a pressed air and it can be processed by rotating the diamond wheel with a constantly varied air pressure perpendicular to workpiece surface, and that the workpiece in the super-mirror face grinding machine for the particle size of $3000No./mm^2$ can be processed to state of mirror face that is rarely seen by the cusp height. It is also found that the surface hardness of both the conventional and the super-mirror face grinding machines are increased as the particle size of diamond wheel is reduced, and the surface hardness of the super-mirror face grinding machine is HRC 1.1 ~ 1.8 higher than that of the conventional one.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1911-1930
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• 2017

Overlay routing has emerged as a promising approach to improve reliability and efficiency of the Internet. The key to overlay routing is the placement and maintenance of the overlay infrastructure, especially, the selection and placement of key relay nodes. Spurred by the observation that a few relay nodes with high betweenness centrality can provide more optimal routes for a large number of node pairs, we propose a resilient routing overlay network construction method by introducing Super-Relay nodes. In detail, we present the K-Minimum Spanning Tree with Super-Relay nodes algorithm (SR-KMST), in which we focus on the selection and connection of Super-Relay nodes to optimize the routing quality in a resilient and scalable manner. For the simultaneous path failures between the default physical path and the overlay backup path, we also address the selection of recovery path. The objective is to select a proper one-hop recovery path with minimum cost in path probing and measurement. Simulations based on a real ISP network and a synthetic Internet topology show that our approach can provide high-quality overlay routing service, while achieving good robustness.

• Journal of Construction Engineering and Project Management
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• 제3권3호
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• pp.17-22
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• 2013

In many urban cities, super-tall buildings have been being constructed around New York and Chicago as the center since 1930 to improve the efficiency of land use and respond to new residential type. In terms of energy consumption, super-tall buildings are classified as a top energy consumption building. Also, as time passed, the degradation of energy performance occurs in super-tall buildings like general things so that these cannot show the initial performance planned in the design phase. Accordingly, building owners need to make a plan to apply energy saving measures to existing building during the operation phase. In order to select energy saving measures, calculus-based methods and enumerative schemes have been typically used. However, these methods are time-consuming and previous studies which used these methods have problems with not considering the initial construction cost. Consequently, this study proposes a model for selecting an optimal combination of energy saving measures which derives maximum energy saving within allowable cost using genetic algorithms. As a contribution of this research, it would be expected that a model is utilized as one of the decision-making tools during the planning stage for energy saving.

• 국제초고층학회논문집
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• 제10권3호
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• pp.203-210
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• 2021

With the development of urbanization, the increasing of buildings density in urban core areas result in the complexity of construction environment. High-rise landmark building is always preferred in the construction of urban core areas. Super high-rise buildings construction are facing construction management difficulties due to the complex working conditions and enormous building system, especially with the complex surrounding environment of the urban core area, the construction management of super high-rise buildings in the area requires higher, refined and detailed standard. Based on a super high-rise project in a core area of Shanghai which has 370 m building height and 772,643 m² building area, with complex surrounding environment, narrow construction site and many super-high-altitude crossing works. With the application of BIM technology, the Internet of Things, the LAN communication and other various intelligent mechanical equipment, information management systems, the efficiency and refinement of construction management are improved, ensuring the smooth implementation of the project while effectively controlling the impact on the surrounding environment.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.294-299
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• 2013

In many urban cities, super-tall buildings have been being constructed around New York and Chicago as the center since 1930 to improve the efficiency of land use and respond to new residential type. In terms of energy consumption, super-tall buildings are classified as a top energy consumption building. Also, as time passed, the degradation of energy performance occurs in super-tall buildings like general things so that these cannot show the initial performance planned in the design phase. Accordingly, building owners need to make a plan to apply energy saving measures to existing building during the operation phase. In order to select energy saving measures, calculus-based methods and enumerative schemes have been typically used. However, these methods are time-consuming and previous studies which used these methods have problems with not considering the initial construction cost. Consequently, this study proposes a model for selecting an optimal combination of energy saving measures which derives maximum energy saving within allowable cost using genetic algorithms. As a contribution of this research, it would be expected that a model is utilized as one of the decision-making tools during the planning stage for energy saving.

• Wind and Structures
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• 제14권3호
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• pp.253-283
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• 2011

This paper presents the field measurement results of wind effects on a super-tall building (CITIC Plaza, 391 m high) located in Guangzhou. The field data such as wind speed, wind direction and acceleration responses were simultaneously and continuously recorded from the tall building by a wind and vibration monitoring system during two typhoons. The typhoon-generated wind characteristics including turbulence intensity, gust factor, peak factor, turbulence integral length scale and power spectral density of fluctuating wind speed were presented and discussed. The dynamic characteristics of the tall building were determined based on the field measurements and compared with those calculated from a 3D finite element model of the building. The measured natural frequencies of the two fundamental sway modes of the building were found to be larger than those calculated. The damping ratios of the building were evaluated by the random decrement technique, which demonstrated amplitude-dependent characteristics. The field measured acceleration responses were compared with wind tunnel test results, which were found to be consistent with the model test data. Finally, the serviceability performance of the super-tall building was assessed based on the field measurement results.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.527-538
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• 2021

The purpose of the study is to determine the efficiency, position, and partner selection of securities companies via the negative super-SBM model used in data envelopment analysis (DEA). This model utilizes a variety of inputs, including current assets, non-current assets, fixed assets, liabilities, owner's equity and charter capital, and outputs including net revenue, gross profit, operating profit, and net profit after tax collected from the financial reports (Vietstock, 2020) of 32 securities companies, operating during the period from 2016 to 2019, negative data are collected as well. Empirical results determined both efficient and inefficient terms, and then further determined the position of each securities firm under consideration of every term. The overall score arrived at discovered a large performance change realizing a maximum score able to reach 20.791. In the next stage, alliancing inefficient companies was carried out based on the 2019 scores to seek out optimal partners for the inefficient companies. The tested result indicated that AAS was the best partner selection when its partners received a good result after alliancing, as with FTS (11.04469). The partner selection is deemed as a solution helpful to inefficient securities companies in order to improve their future efficiency scores.