• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1851-1863
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• 2014

Many countries are increasing their investments in smart grid technology to enhance energy efficiency, address climate change, and trigger a green energy revolution. In addition to these goals, Korea also seeks to promote national competitiveness, prepare for the growth of the renewable energy industry, and export industrialization through its strategic promotion of the smart grid. Given its inherent representativeness for Korean implementation of the smart grid and its growth potential, Jeju Island was selected by the Korean government as the site for smart grid testing in June 2009. This paper presents a new design for the electricity market and an operational scheme for testing Smart Electricity Services in the Jeju smart grid demonstration project. The Jeju smart grid test-bed electricity market is constructed on the basis of day-ahead and real-time markets to provide two-way electricity transaction environments. The experience of the test-bed market operation shows that the competitive electricity market can facilitate the smart grid deployment in Korea by allowing various demand side resources to be active market players.

• 한국정보통신학회논문지
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• 제2권3호
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• pp.335-341
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• 1998

본 논문에서는 CS-ACELP(Conjugate Structure Algebraic Code Excited Linear prediction) 음성부호화기의 실시간 구현에 관하여 논한다. CS-ACELP 알고리즘은 ITU-T에서 G.729로 표준화되었다. CS-ACELP 음성부호화 알고리즘의 실시간 구현은 16비트 정수형 DSP 칩을 사용하였다. 16비트 정수형 DSP 칩상에 구현하기 위하여, CS-ACELP 알고리즘의 정수형 시뮬레이션을 사용하였다. CS-ACELP 음성부호화기에 포함된 입출력기능과 통신 기능을 설명한다. DSP Evaluation board를 사용하여 CS-ACELP 음성부호화기를 개발하였고 IMT-2000 Test-bed를 사용하여 검증하였다.

• International journal of advanced smart convergence
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• 제12권1호
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• pp.208-219
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• 2023

Recently, as mega-urbanization progresses, urban logistics centered on large cities is growing rapidly, and logistics transportation is increasing due to the lack of logistics infrastructure and the operation of a delivery system using cargo trucks in the city center. being cited as a cause. In order to solve this problem, domestic researchers are conducting research on the development of " Urban Underground railway Logistics System" that minimizes the initial infrastructure construction cost by utilizing the existing urban railway facilities in the city. Therefore, this paper analyzed the usage environment of the actual urban railway station to which the system will be applied in order to derive candidates for the test bed selection of "Urban Underground railway Logistics System". The evaluation criteria for test bed candidate role selection were established, and the candidate group derived from the Brown & Gibson model was used to evaluate the candidate group and derive the candidate role. A review of the results was conducted to contribute to the establishment of a test bed for the " Urban Underground railway Logistics System" under development.

• 한국전기전자재료학회논문지
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• 제36권2호
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• pp.151-157
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• 2023

Integrating dielectric materials into LTCC is a convenient method to increase the integration density in electronic circuits. To enable co-firing of the high-k and low-k dielectric LTCC materials in a multi-material hetero-laminate, the shrinkage characteristics of both materials should be similar. Moreover, thermal expansion mismatch between materials during co-firing should be minimized. The alternating stacking of an LTCC with silica filler and that with calcium-zirconate filler was observed to examine the use of the same glass in different LTCCs to minimize the difference in shrinkage and thermal expansion coefficient. For the LTCC of silica filler with a low dielectric constant and that of calcium zirconate filler with a high dielectric constant, the amount of shrinkage was examined through a thermomechanical analysis, and the predicted appropriate fraction of each filler was applied to green sheets by tape casting. The green sheets of different fillers were alternatingly laminated to the thickness of 500 ㎛. As a result of examining the junction, it was observed through SEM that a complete bonding was achieved by constrained sintering in the structure of 'calcium zirconate 50 vol%-silica 30 vol%-calcium zirconate 50 vol%'.

• Earthquakes and Structures
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• 제26권5호
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• pp.363-382
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• 2024

In India's north-eastern region, low-strength autoclaved aerated concrete (AAC) blocks are widely used for constructing masonry structures, making them susceptible to lateral forces due to their low tensile and shear strengths and brittleness nature. The absence of earthquake-resistant attributes further compromises their resilience during seismic events. An economically viable solution to enhance the structural integrity of these masonry structures involves integrating steel wire mesh within the masonry mortar joints. This study investigates the in-plane shear behaviour of AAC masonry by employing two approaches: incorporating steel wire mesh within the masonry bed joint "BJ" and the masonry bed and head joint "BHJ". These approaches aim to augment strength and ductility, potentially serving as earthquake-resistant attributes in masonry structures. Three distinct variations of steel wire mesh and three reinforcing arrangements, i.e. (-), (L) and (Z) arrangement were employed to reinforce the two approaches. The test result reveals a significant enhancement in structural performance upon inclusion of steel wire mesh in both reinforcing approaches, with the "BHJ" approach outperforming the "BJ" approach and the unreinforced masonry, along with increase in capacity as the wire mesh size increases. Furthermore, the effectiveness of the reinforcing arrangement is ranked with the (Z) arrangement showing the largest performance, followed by the (L) and (-) arrangement.

• 한국ITS학회 논문지
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• 제15권4호
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• pp.115-128
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• 2016

전 세계적으로 도로 상에서의 교통사고를 줄이고 교통 효율을 향상시키기 위한 많은 연구가 수행되어 왔으며, 최근에는 특히 C-ITS(Cooperative Intelligent Transportation System, 협력형 지능형교통체계) 기술을 기반으로 한 연구가 활발히 진행되고 있다. C-ITS 기술의 핵심은 인프라, 차량, 사람 등 도로시스템을 구성하는 요소들이 서로 간에 정보를 공유하고 재생성함으로써 도로안전 및 교통효율의 향상을 도모하는 것이며, 이를 위해 차량용 무선통신기술인 V2X(Vehicle-to-X) 통신기술이 적용되고 있다. 국내에서는 스마트하이웨이 연구를 통해 V2X 통신기술에 대한 연구가 진행되어 왔으며, 실제 고속도로 환경에서의 기술성능을 검증하기 위해 테스트베드를 구축하여 운영하고 있다. 본 논문에서는 스마트하이웨이 테스트베드에 대해 간략히 소개하고, 테스트베드 상에서의 성능 분석 절차 및 결과에 대해 기술한다.

• 한국전자파학회논문지
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• 제11권4호
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• pp.523-533
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• 2000

본 논문에서는 국내 광대역 CDMA WLL(Wireless Local Loop) 규격올 적용한 스마트안테나 시스템의 빔 형성모듈을 설계, 제작하여 본 연구실에서 제안한 빔형성 알고리즘의 수신신호 성능을 실시간으로 분석할 수 있는 시연시스템을 제안하였다. 본 논문에서 소개되는 시연시스템은 범형성모듈뿐 아니라, 빔형성모듈의 성능을 확인 . 평가. 분석하기 위한 PC와 인터페이스 장치인 테스트 모률(신호생성모률)이 포함된다. 빔형성모율 에서는 자체 개발한 CGM(Conjugate Gradient Meth떠)알고리즘을 이용하여 최적의 웨이트 벡터를 생성시켜 주며, 계산된 웨이트 빽터는 PC로 전달되어 다양한 성능분석을 수행하게 한다. 스마트 안테나 시스템을 직접 구현 하여 성능을 분석한 결과, CDMA WLL 기지국에 스마트 안테나를 사용함으로써 대폭적인 통신품질 향상 및 용량 증대가 될 것으로 판단된다.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.180-189
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• 2023

We measured the heat load to a reactor vessel with and without the in-vessel debris bed under an IVR-ERVC condition. Mass transfer methodology was adopted based on heat and mass transfer analogy to achieve high Ra'_H of order ~10¹⁵ with compact test rigs. We postulated the in-vessel debris bed has a flat top and particulate debris was simulated as an identical diameter spheres. We conducted experiments varying the height of the debris bed and the results showed that Nusselt numbers decreased in both uppermost and curved surfaces with the increasing bed height. Once the debris bed is formed, it acts as an obstacle to the natural convective flow, which reduces the buoyancy. The reduction of driving force results in the impaired heat transfer in both upward and downward heat transfers.

• Geomechanics and Engineering
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• 제4권2호
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• pp.79-90
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• 2012

Air pluviation method is widely adopted for preparation of large, uniform and repeatable sand beds of desired densities for laboratory studies to simulate in-situ conditions and obtain test results which are highly reliable. This paper presents details of a portable traveling pluviator recently developed for model sand bed preparation. The pluviator essentially consisted of a hopper, orifice plates for varying deposition intensity, combination of flexible and rigid tubes for smooth travel of material, and a set of diffuser sieves to obtain uniformity of pluviated sand bed. It was observed that sand beds of lower relative density can be achieved by controlling height of fall, whereas, denser sand beds could be obtained by controlling deposition intensity. Uniformity of pluviated sand beds was evaluated using cone penetration test and at lower relative densities minor variation in density was observed with depth. With increase in relative density of sand bed higher repeatability of uniform pluviation was achieved.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.63-63
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• 2021

Bed shear stress is important variable in river flow analysis. The bed shear stress has an effects on bed erosion, sediment transport, and mean flow characteristics. Quadratic formula to estimate bed shear stress is widely used, 𝜏=𝜌c_fu|u| in which friction coefficient, c_f, needs to be assigned to numerical models. The aim of this study is to estimate Chezy coefficient using bathymetry data measured by ADCP. Bed form geometry variables will be estimated form bed profile, then Chezy coefficient will be determined using estimated bed form geometry variables in order to set friction coefficient to numerical model. From the probability density function obtained from the bathymetry data, Chezy coefficient will be randomly generated since Chezy coefficient is not uniform over the space and it does not depend on spatial variables such as water depth and distance from river bank. Numerical test will be performed to find to demonstrate randomly extracted Chezy coefficient is appropriate. The result of this study is valuable in that the friction coefficient is estimated in consideration of the bed profile, and as a result, uncertainty of the friction coefficient can be reduced.