• Advances in concrete construction
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• 제2권1호
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• pp.13-27
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• 2014

The principal objective of this study is to deepen the characterization studies already led on sand concretes in previous works. Indeed, it consists in studying the effect of the sand type on the main properties of sand concrete: fracture and mechanical properties. We particularly insist on the determination of the fracture characteristics of this material which apparently have not been studied. To carry out this study, four different types of sand have been used: dune sand (DS), river sand (RS), crushed sand (CS) and river-dune sand (RDS). These sands differ in mineralogical nature, grain shape, angularity, particle size, proportion of fine elements, etc. The obtained results show that the particle size distribution of sand has marked its influence in all the studied properties of sand concrete since the sand having the highest diameter and the best particle size distribution has given the best fracture and mechanical properties. The grain shape, the angularity and the nature of sand have also marked their influence: thanks to its angularity and its limestone nature, crushed sand yielded good results compared to river and dune sands which are characterized by rounded shape and siliceous nature. Finally, it should further be noted that the sand concrete presents values of fracture and mechanical properties slightly lower than those of ordinary concrete. Compared to mortar, although the mechanical strength is lower, the fracture parameters are almost comparable. In all cases, the sand grains are debonded from the paste cement during the fracture which means that the crack goes through the paste-aggregate interface.

• 한국주거학회논문집
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• 제17권4호
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• pp.145-153
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• 2006

Ubiquitous space can be described as a combined space of physical space and digital space. Ubiquitous space possesses new possibilities by combining the two. The concept of ubiquitous home will bring new changes in residential space design. First of all, it makes possible for more convenient and secure home. It has to be developed along with city and town level changes as ubiquitous environment. Secondly, concept of extended space as an extension of living space becomes possible by linking with outside spaces. Thirdly, as consumer requirements for residential spaces will become more versatile by social changes, ubiquitous home can be a good means to meet these versatile consumer requirements by accommodating concept of multi-functional space and flexible space. It is quite important to predict user requirements in rapidly changing social environment and versatile personal inclinations. Instead of POE methodology which can analyze and evaluate in exiting types of designs, storytelling methodology can be used to predict and direct for future requirements of living. The methodology makes scenarios of space usage for future living and extracts design requirements for the living. The concept of intelligent space has to be introduced. It is different from digital home that only accomodate digital devices in space. In intelligent space, space itself has to be recognized as an identity that interacts human directly. Intelligent space recognize human requirements and control digital devices as a response. Multi-functional space is closely related with intelligent space that can changes for business, entertainments as well as for rests by user requirements instantly. Flexible space that also intends to meet requirements of mobility and versatility can be attained through the integration of digital technology into current physical mobile systems. Interaction design becomes integral part for ubiquitous space design along with physical design. For the residential space design, digital illiteracy has to be considered for interaction design. Instead of the concept of passive existence, space itself has to be recognized as active subsistence that reacts with human. Intuitive and natural interaction for human will be a key design element for space-human interface design.

• 한국통신학회논문지
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• 제2권1호
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• pp.2-13
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• 1977

政治. 經濟. 文化등 社會現象과 함께 社會作用 또는 社會課題의 하나로서 通信은 合理的 屬性을 지닌 한 개 領域의 科學으로 發展하고 있다. 이 科學은 1950年代에 美國에서 形成되어 世界的으로 擴大傳播되고 있다. 우리의 社會開發과 國家發展을 위하여 우리에게도 이것이 受容되어야 한다고 인정되어 1975年2月에는 學術團 로서 韓國通信學會가 結成된 바 있다. 通信科學이란 그 內部的 各要素 및 그 要素間의 科學性과 相關性을 分析 追求하는 것과 通信機能을 중심으로 한 周邊諸科學과의 관계의 系化하고 效率化하여 通信機能으로 하여금 人類福祉를 위하여 最大의 貢猷을 導出하는 學域이다. 다시 말하면 通信科學은 通信實際를 기반으로 그 原理와 學說을 論理的으로 系化하고 이것을 最大로 應用하는 理論과 方法을 探求하는 일이며 無窮한 將來可能性을 안고 있다. 따라서 關係學者 敎育者 從事者 미 管理者 등 通信內部의 當事者는 먼저 通信에 대한 意識과 認識등 通信觀을 새로운 것 또는 科學的인 것으로 革新할 것과 通信의 科學的 및 自主性을 '||'&'||'#20307;得하여야 함이 先行되어야 하겠다.

• Journal of Advanced Marine Engineering and Technology
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• 제12권2호
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• pp.21-34
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• 1988

Machinery enclosures are widely adopted to reduce the noise emission in various fields of application. Emitted noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound with different path of propagation. One is the "structure-borne sound", while the other is "air-borne sound". In order to get a most efficient machinery enclouser a prudent consideration upon the above structure-borne and air-borne sound is required, as the guiding principle of contermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subjects for the structure-borne sound, and the specifications of absorbing members and damping panels are the major related matters for the air-borne sound. Hence, it seems very efficient to separate the total sounds into two categories with a great accuracy when one think of further reduction of noise from the existing enclosure, although its separating methods have not been made clear for many years. Author proposes an application method of experimental modal analysis to extract the structure-borne sound from the measured total radiation sound, as the air-borne sound is deduced by the vectorial difference between the measured total radiation sound and the calculated structure-borne sound. In order to calculate the correct structure-borne sound by the excitation at an arbitrary point on the enclosure structure, it is important to decide 1) how to estimate the enclosure's surface vibration velocity and 2) how to compute the radiation sound which is considered as the effect of vibration modes of enclosure surface. The former can be solved with total frequency response function calculated by the application of experimental modal analysis. The latter is to be solved by the author's new approaches for radiation sound computation by means of the Rayleigh's integral equation and the boundary-element method applied complex surface vibration velocity. As a first step, structure-borne sound by the excitation at an arbitry point on the rectangular plate with fixed edges, has been calculated to verified the reliability of the developed computation methods. The results of calculation show good agreements with those of the actual measurements.actual measurements.

• Structural Engineering and Mechanics
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• 제72권6호
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• pp.675-687
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• 2019

As the bridges are an integral part of the transportation network, their function as one of the most important vital arteries during an earthquake is fundamental. In a design point of view, the bridges piers, and in particular the wall piers, are considered as effective structural elements in the seismic response of bridge structures due to their cantilever performance. Owing to reduced seismic load during design procedure, the response of these structural components should be ductile. This ductile behavior has a direct and decisive correlation to the development of plastic hinge region at the base of the wall pier. Several international seismic design codes and guidelines have suggested special detailing to assure ductile response in this region. In this paper, the parameters which affect the length of plastic hinge region in the reinforced concrete bridge with wall piers were examined and the sensitivity of these parameters was evaluated on the length of the plastic hinge region. Sensitivity analysis was accomplished by independently variable parameters with one standard deviation away from their means. For this aim, the Monte Carlo simulation, tornado diagram analysis, and first order second moment method were used to determine the uncertainties associated with analysis parameters. The results showed that, among the considered design variables, the aspect ratio of the pier wall (length to width ratio) and axial load level were the most important design parameters in the plastic hinge region, while the yield strength of transverse reinforcements had the least effect on determining the length of this region.

• 한국멀티미디어학회논문지
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• 제16권4호
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• pp.483-492
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• 2013

SURF는 영상의 특징점을 추출하고 서술자를 생성하는 알고리즘으로 객체인식 및 추적, 파노라마 이미지 생성 등 여러 영상처리 시스템에 응용되고 있다. SURF 알고리즘은 영상의 크기, 회전, 시점 등의 변화에 강인한 특징을 갖지만 복잡하고 반복적인 연산이 많아 실시간 처리가 어렵다. 실제 PC(Pentium, 3.3GHz) 환경에서 1000개 정도의 특징점이 추출되는 VGA($640{\times}480$) 해상도의 영상을 이용하여 실험한 결과 특징점 추출 및 서술자 생성에 총 240ms 이상이 걸려 약 4frame/sec로 실시간 처리가 불가능한 것을 확인하였다. 본 논문에서는 SURF 알고리즘의 메모리 접근 패턴을 분석하여 라인 메모리를 효율적으로 구성해 메모리 사용을 최소화하고 반복적으로 수행되는 연산을 병렬처리 하는 방법으로 하드웨어를 설계하였다. 하드웨어 설계 검증 결과 Xilinx사의 Virtex5LX330 FPGA를 타겟으로 합성 시 101,348LUTs(66%)와 1,367KB의 내부 메모리를 사용하고, 100MHz 동작 클록에서 30 frame/sec로 실시간 처리가 가능함을 볼 수 있었다.

• 복식
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• 제51권1호
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• pp.5-20
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• 2001

The purpose of this study suggest the fashion of communication for 21th century fashion. Especially, Memphis fashion have the possibility of communicating through objects. The results of this study are as follows : First, Memphis idea is to make design into a sophisticated, conscious instrument of communication. As the Memphis fashion points out : design is an extraordinary tool for communicating because its intrinsic characteristic is the fact that it is used and distributed anyway, even without communicating anything. The Memphis fashion is trying to connect design and industry to the broader culture within which fashion moves. Second, Using different materials provides not only new structural Possibilities. but - above all - new semantic and metaphoric possibilities, order modes of communication, another language, and even a change of direction, broadening of perspective, appropriation and digestion of new values and the concomitant rejection of traditional structures that renewal always Involves. The memphis fashion works on the fabric of contemporaneity (lurex yarn, latex, chrome metal and steel) and contemporaneity means computers, electronics, a new awareness of the body. mass exercise and tourism. Third, color in Memphis has never been an ideological vehicle. As with decoration it is born tilth the design, forming an integral part of the structure. It alters the objects molecules. It works as a mass, as an intrinsic feature of a certain form and volume. The Memphis fashion was realized the introduction of ultramodern science into such experimental and creative implementation as optical motive, brilliancy of colour of electronic medium in audition to metallic fabric and high technical synthetic fiber. A color tilth pop culture connotations that weaver between technological allusions and Mcdonald's.

• 한국생산제조학회지
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• 제22권3_1spc호
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• pp.573-579
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• 2013

Once-through helically coiled steam generator tubes subjected to external pressure are of interest because of their application to advanced small- and medium-sized integral reactors, in which a primary coolant with a relatively higher pressure flows outside the tubes, while secondary water with a relatively lower pressure flows inside the tubes. Another notable point is that the values of the mean radius to thickness ratio of these steam generator tubes are very small, which means that a thick-walled cylinder is employed for these steam generator tubes. In the present paper, the maximum allowable pressure of helically coiled and thick-walled steam generator tubes with through-wall cracks under external pressure is investigated based on a detailed nonlinear three-dimensional finite element analysis. In terms of the crack orientation, either circumferential or axial through-wall cracks are considered. In particular, in order to quantify the effect of the crack location on the maximum external pressure, these cracks are assumed to be located in the intrados, extrados, and flank of helically coiled cylinders. Moreover, an evaluation is also made of how the maximum external pressure is affected by the ovality, which might be inherently induced during the tube coiling process used to fabricate the helically coiled steam generator tubes.

• 대한기계학회논문집A
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• 제36권7호
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• pp.797-803
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• 2012

비례솔레노이드밸브는 코일전류에 비례하는 전자기력을 이용하여 밸브 변위를 연속적으로 가변시키는 밸브이다. 대용량 비례유량제어밸브는 발전소나 화학 플랜트에서 물, 스팀, 가스 등과 같은 공정유체의 대용량 유량제어에 사용되며 공압이나 모터를 이용하는 밸브에 비하여 우수한 응답성능과 소형화의 장점을 가진다. 본 연구에서는 비례제어밸브를 대상으로 밸브의 동적 특성을 식별한 후 목표 성능이 만족되도록 위치제어기의 비례적분이득을 자동으로 조정하는 기능을 설계하였다. 동특성 식별은 릴레이 피드백을 통하여 한계 안정 상태에서의 임계이득과 임계주기로 파악하였으며, 비례적분이득 결정에는 Ziegler-Nichols 방법을 적용하였다. 구현된 기능은 시험을 통하여 성능을 검증하였으며 밸브 작동점과 릴레이 제어기 변수가 자동조정에 미치는 영향을 분석하였다.

• Journal of Communications and Networks
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• 제13권6호
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• pp.552-566
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• 2011

The Internet is a very successful modern technology and is considered to be one of the most important means of communication. Despite that success, fundamental architectural and business limitations exist in the Internet's design. Among these limitations, we focus on a specific issue, the lack of manageability, in this paper. Although it is generally understood that management is a significant and important part of network and service design, it has not been considered as an integral part in their design phase. We address this problem with our future Internet management architecture called highly manageable network and service architecture for new generation (HiMang), which is a novel architecture that aims at integrating management capabilities into network and service design. HiMang is highly manageable in the sense that it is autonomous, scalable, robust, and evolutionary while reducing the complexity of network management. Unlike any other management framework, HiMang provides management support for the revolutionary networks of the future while maintaining backward compatibility for existing networks.