• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.107-119
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• 2021

The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.

• Nuclear Engineering and Technology
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• v.45 no.3
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• pp.385-392
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• 2013

Zirconium and zirconium alloys are widely used as nuclear reactor core materials such as fuel cladding and guide tubes because they have excellent corrosion- and radiation-resistant properties. In the reactor core, zirconium alloys are subjected to high-energy neutron fluence, causing radiation-induced dislocation and growth. To discern a possible correlation between radiation-induced dislocation and growth, characteristics of dislocation and growth in zirconium and its alloys are examined. The radiation-induced dislocation including and dislocation loops is reviewed in various temperature and fluence ranges, and their growth behavior is examined in the same way. To further a fundamental understanding, radiation-induced growth prediction models are briefly reviewed. This research will assist in the design of zirconium based components as well as the safety analysis of various reactor conditions, in both research and commercial reactors.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.154-157
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• 2010

현재 자동차 네비게이션의 위치검색 기능은 사용자가 해당 지역과 주유소 선택을 하면 사용자에게 리스트로 결과를 출력하는 일반적인 검색 방법을 사용한다. 그러나 대부분의 운전자들은 주로 이용하는 주유 업체가 정해져 있고 현재 자동차의 연료 잔량, 리터당 연료의 가격 등의 조건이 정해져 있다. 따라서 본 논문에서는 운전자가 주유소를 결정하는 상황정보 등, 몇 가지 주요 조건을 제시하고, 운전자에게 불필요한 주유소 정보를 제공하지 않도록 운전자의 개인정보에 의한 지능형 검색을 하게 한다. 최종적으로 GIS 분석을 통해 최적의 주유소 검색을 제공하는 시스템을 설계한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.11-13
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• 2023

의미론적 분할(Semantic Segmentation)은 이미지 내의 객체 및 배경을 픽셀 단위로 분류하는 작업으로 정밀한 탐지가 요구되는 분야에서 활발히 연구되고 있다. 기존 어텐션 기법은 의미론적 분할의 다운샘플링(Downsampling) 과정에서 발생하는 정보손실을 완화하기 위해 널리 사용됐지만 고정된 Convolution 필터의 형태 때문에 객체의 형태에 따라 유동적으로 대응하지 못했다. 본 논문에서는 이를 보완하고자 Deformable Convolution과 셀프어텐션(Self-attention) 구조기반 어텐션 모듈을 사용한 의미론적 분할 모델을 제안한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.164-165
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• 2012

집중호우 및 홍수로 인해 침수지역이 발생할 경우 이를 예측하기 위해 IT를 융합한 방재에 대한 연구가 필요하며 특히 본 논문에서는 도시 침수에 대비하여 교통 통제, 우회 도로 등을 제공하기 위해 정량적인 침수 위험 지수를 접목시키는 방안에 대하여 연구하였다.

• Smart Structures and Systems
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• v.1 no.1
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• pp.1-12
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• 2005

This paper describes the area of intelligent systems research as funded by the Civil and Mechanical Systems (CMS) Division of the National Science Foundation (NSF). With developments in computer science, information technology, sensing and control the design of typical machines and structures by civil and mechanical engineers is evolving toward intelligent systems that can sense, decide and act. This trend toward electro-mechanical design is well-established in modern machines (e.g. vehicles, robots, disk drives) and often referred to as mechatronics. More recently intelligent systems design is becoming an important aspect of structures, such as buildings and bridges. We briefly review recent developments in structural control, including the role that NSF has played in their development, and discuss on-going CMS activities in this area. In particular, we highlight the interdisciplinary initiative on Sensors and Sensor Networks and the Network for Earthquake Engineering Simulation (NEES). NEES is a distributed cyberinfrastructure to support earthquake engineering research, and provides the pioneering NEES grid computing environment for simulation, teleoperation, data collection and archiving, etc.

• International Journal of High-Rise Buildings
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• v.7 no.1
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• pp.47-64
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• 2018

The last decade has seen great design opportunities for tall building construction around the globe. The best designs represent a new generation of skyscrapers that go beyond willful preconceptions of building form and iconography, trying instead to simultaneously address interrelated issues of program space utility, structural efficiency, and environmentally sustainable systems. The resulting identities of these towers are unique because of their search for the intersection of spaces tuned to people's needs, expressive optimized structures, and high performance, site-responsive systems. This paper, through examples of recent SOM towers, both built and unbuilt, will discuss how a design becomes content-driven, how ideas create value, and how the typology of the tall building is advanced through the integration of architecture design and engineering systems.

• Transactions on Electrical and Electronic Materials
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• v.9 no.4
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• pp.163-168
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• 2008

Photonic crystal structures have been received considerable attention due to their high optical sensitivity. One of the techniques to construct their structure is the dip-pen lithography (DPN) process, which requires a nano-scale resolution and high reliability. In this paper, we propose a two dimensional photonic crystal array to improve the sensitivity of optical biosensor and DPN process to realize it. As a result of DPN patterning test, we have observed that the diffusion coefficient of the mercaptohexadecanoic acid (MHA) molecule ink in octanol is much larger than that in acetonitrile. In addition, we have designed and fabricated optical waveguides based on the mach-zehnder interferometer (MZI) for application to biosensors. The waveguides were optimized at a wavelength of 1550 nm and fabricated according to the design rule of 0.45 delta%, which is the difference of refractive index between the core and clad. The MZI optical waveguides were measured of the optical characteristics for the application of biosensor.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.335-342
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• 2023

Lunar Navigation Satellite System refers to a constellation of satellite providing PNT services on the moon. LNSS consists of main satellite and navigation satellites. Navigation satellites orbiting around the moon and a main satellite moves the area between the moon and the L2 point. The navigation satellite performs the same role as the Earth's GNSS satellite, and the main satellite communicates with the Earth for time synchronization. Due to the effect of the non-uniform shape of the moon, it is necessary to focus on the influence of the lunar gravitational field when designing the orbit simulation for navigation satellite. Since the main satellite is farther away from the moon than the navigation satellite, both the earth's gravity and the moon's gravity must be considered simultaneously when designing the orbit simulation for main satellite. Therefore, the main satellite orbit simulation must be designed through the three-body problem between the Earth, the moon, and the main satellite. In this paper, the orbit simulation tool for main satellite and navigation satellite required for LNSS was designed. The orbit simulation considers the environment characteristics of the moon. As a result of comparing long-term data (180 days) with the commercial program GMAT, it was confirmed that there was an error of about 1 m.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.331-337
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• 2009

This paper summarizes some of approaches that could be taken for data exchange in a non-interoperable work environment and reports lessons learned from the Dongdaemun Design Plaza and Park project. Today's widespread application of building information modeling (BIM) to the construction and architectural design industries requires a change in the cooperation between business organizations and their methods of communication. In particular, the interoperability of information between interdisciplinary organizations, which use specific programs for different purposes, has become a critical issue. More than just a technical problem, it is also highly related to an organization's collaboration culture and the particulars of a specific project. This paper describes the interoperability issue that occurred during the construction documentation phase of the irregularly shaped building project, Dongdaemun Design Plaza and Park, designed by Zaha Hadid Architects and Samoo Architects and Engineers, from the perspective of the technological problem and the collaborative organizations' communications. Although the perfect compatibility of information is not possible, this paper deals with a practical approach to the interoperability issue by examining the way the end-users of computer-aided design (CAD) resolved the interoperability problems in practice.