• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.435-451
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• 2015

Evaluation of the performance of aging structures is essential in the oil and gas industry, where the inaccurate prediction of structural performance can have significantly hazardous consequences. The effects of structure failure due to the significant reduction in wall thickness, which determines the burst strength, make it very complicated for pipeline operators to maintain pipeline serviceability. In other words, the serviceability of gas pipelines and elbows needs to be predicted and assessed to ensure that the burst or collapse strength capacities of the structures remain less than the maximum allowable operation pressure. In this study, several positions of the corrosion in a subsea elbow made of API X42 steel were evaluated using both design formulas and numerical analysis. The most hazardous corrosion position of the aging elbow was then determined to assess its serviceability. The results of this study are applicable to the operational and elbow serviceability needs of subsea pipelines and can help predict more accurate replacement or repair times.

• 대한건축학회논문집:계획계
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• 제34권8호
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• pp.31-41
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• 2018

This research examines pioneering works of two representative Western modern architects which played a significant role in constructing modernity in the early 20th century: Frank Lloyd Wright's Florida Southern College and Ludwig Mies van der Rohe's Illinois Institute of Technology. These two campuses were constructed and developed at the similar period by two named architects, and these were considered the collections of iconic modern buildings in the States. However, design approaches and principles of these buildings were totally opposite ways: Frank Lloyd Wright's Florida Southern College was in the roof of organic architecture drawn from a great Chinese sage, Laotze, which have more five hundred years history. On the other hand, Ludwig Mies van der Rohe's Illinois Institute of Technology was well embodied the International Style which originated from European tradition in the early 20th century, and Mies was one of the leaders of the International Style. These different approaches could be understood in the discussion of the meaning of the Greek concept of paradoxa which was mentioned by a German philosopher Martin Heidegger. Comparing the paradoxical gestures of these two campuses can reveal the truth of each campus master plans and expand the discourse of modern architectures.

• Structural Engineering and Mechanics
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• 제52권3호
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• pp.613-632
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• 2014

In the early design stage of ships, the two most important structural analyses are performed to identify the structural capacity and safety. The first step is called global strength analysis (longitudinal strength analysis or hull girder strength analysis) and the second step is local buckling analysis (stiffened panel strength analysis). This paper deals with the ultimate strength performance of Arctic Sea Route-going commercial ships considering the effect of low temperature. In this study, two types of structural analyses are performed in Arctic sea conditions. Three types of ship namely oil tanker, bulk carrier and container ship with four different sizes (in total 12 vessels) are tested in four low temperatures (-20, -40, -60 and $-800^{\circ}C$), which are based on the Arctic environment and room temperature ($20^{\circ}C$). The ultimate strength performance is analysed with ALPS/HULL progressive hull collapse analysis code for ship hulls, then ALPS/ULSAP supersize finite element method for stiffened panels. The obtained results are summarised in terms of temperature, vessel type, vessel size, loading type and other effects. The important insights and outcomes are documented.

• International Journal of Railway
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• 제1권3호
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• pp.83-88
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• 2008

Since the 1990's the fleet of the Dutch Railways showed a dramatic decrease in wheel tyre life. This lifetime reduction led to an unacceptable increase in life cycle costs. Therefore Lloyd's Register Rail has proposed to NedTrain to investigate the possibilities of improving the wheel tyre life. Three improvements were determined as most promising and relatively easy to achieve: - Profile optimisation for Rolling Contact Fatigue (RCF) reduction - a new wheel profile has been developed with a better resistance against rolling contact fatigue of the wheel tread. The profile has been implemented on single deck intercity trains and shows an increase in wheel tyre life of 30%. - Selection of improved wheel tyre materials - combining information from literature and experiences of manufacturers five alternative wheel tyre materials have been selected and are now being tested in practice. - Optimisation of the maintenance strategy - an alternative, preventative maintenance regime has been developed. With this Scraping regime, during short term maintenance every wheel is reprofiled. Higher mileages are reached and savings on life cycle costs up to 50% and more have been achieved. Unplanned maintenance goes down with $30{\sim}60%$. The results from field tests, using a reference group for comparison, and preliminary results after implementation show that the increase in wheel tyre life that is achieved with this project is significant. The results will continue to be monitored using the asset management tool 'Wheel Watch', that was specially developed for this project and is also described in this paper.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2010년도 추계학술대회
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• pp.72-73
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• 2010

본 논문에서는 안테나 당 전력제한 조건 하의 다중 입출력 빔포밍 시스템을 위한 위상 추적 코드북을 제안한다. 위상 추적 빔포밍 방식은 인접한 프레임 정보의 차이만을 활용한다는 점에서 기존의 위상 조정 방식과 차별화 되며, 궤환 정보량의 감소 이득을 얻을 수 있다. 이러한 위상 추적 코드북 구성을 위하여 위상 조정 코드북의 목적함수를 새롭게 변형하여 Lloyd-Max 알고리듬에 적용한다. 성능평가를 위하여 위상 조정 코드북과의 신호 대 잡음비의 비교 수행하며, 이를 이용하여 제안하는 코드북의 효율성을 입증한다.

• 건축역사연구
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• 제14권3호
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• pp.89-102
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• 2005

Frank Lloyd Wright and Mies van der Rohe are two of the most influential architects in modern architecture. In spite of the different values in their architectural lives, the design of high-rise building had been a continuous matter of primary concern for them. The purpose of this study is to compare the architectural characteristics of the two master architects in terms of building form, structure, function, and envelop skin. glass. Both of them shared with the principle of organic architecture even in the design of high-rise buildings. However, the specific approaches to realize it in high-rise buildings are significantly different. Although they emphasized the integration of building form and structure, Wright regarded the reinforced concrete structure as an organic form-giver, while Mies introduced the steel skeleton structure only as an efficient and flexible building frame. As primary finishing materials for high-rise buildings, glass was used for functional purpose by Wright, but for visual purpose by Mies.

• KIEAE Journal
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• 제10권3호
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• pp.17-26
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• 2010

This study aims at exploring the characteristics of the Usonian houses of Frank Lloyd Wright from an ecological viewpoint. After considering the definition and application of ecological architecture through literature review, 28 Usonian houses were selected and analyzed for the study. Also, nine Usonian houses, which clearly have ecological and historical importance, were visited and more thoroughly analyzed. The result shows that Usonian houses are ecological in terms of 1) the relationship among nature, landscape and house, 2) the orientation, natural light and natural ventilation, 3) the use of natural local materials including wood, stones and bricks, 4) the use of floor heating (the On-dol system inKorea), 5) the human scale, 6) the use of the board and batten unit (an early system of prefabrication), and 7) the openness and flexibility of floor plans.

• 대한조선학회논문집
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• 제51권5호
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• pp.380-387
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• 2014

Piper Alpha disaster drew attention to the damage likely to arise from explosions and fires on an offshore platform. And great concerns have been increased to prevent these hazards. Blast wall is one of the passive safety systems; it plays a key part of minimizing the consequences. However, a buckling due to explosion loads is a factor which can reduce the strength of blast wall. The buckling often occurs between web and flange at the center of blast wall. This study aims to find a solution for reinforcing its strength by installing a flat plate at the spot where the buckling occurs. First of all, ANSYS finite element method is adopted to numerically compute the structural resistance characteristic of blast wall by using a quasi-static approach. Sequentially, the impact response characteristics of blast wall are investigated the effect on thickness of flat plate by using ANSYS/LS-DYNA. Finally, pressure-impulse diagrams (P-I diagram) are presented to permit easy assessment of structural response characteristics of stiffened blast wall. In this study, effective use is made to increase structural intensity. of blast wall and acquired important insights have been documented.

• 전자공학회논문지B
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• 제31B권7호
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• pp.26-32
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• 1994

The Lloyd-Max algorithm is an iterative scheme for design of the minimum mean square error quantizer. It is very simple in concept and easy to program into a computer. However its convergence and accuracy are primarily dependent upon the accuracy of the initial parameter. In this paper, a new initial parameter which converges to a specific value when the number of output levels becomes large is selected. And an estimator using curve fitting techique is suggested. In addition, performance of the proposed method is shown to be superior to that of the existing methods in accuracy and convergence.

• 건축사
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• 통권540호
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• pp.94-101
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• 2014