• KIEAE Journal
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• 제3권1호
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• pp.21-29
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• 2003

Scale model measurements should be conducted under an actual sky or in a simulated sky where conditions can be held constant. A number of successful attempts have been made to develop artificial sky domes with man-made sun emulators. With reference to formerly-developed examples, sky simulator facility has recently been activated in oder to provide desirable sky conditions for teaching and studies. The structure is a 6m-diameter dome and promises to set various condition for energy related and lighting research activities. The sky dome is also equipped a heliodon, the tilt table, to facilitate additive direct sun impact under clear skies. Shading studies, using scale models with the heliodon, reveal how a building's design blocks or permits light's passage to the interior; solar access studies, and tests of the reflection and transmittance characteristics of new daylighting technologies. The design and construction specification and the initial operating experience with a building configuration are reported.

• Tribology and Lubricants
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• 제20권1호
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• pp.33-40
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• 2004

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper, show that there is a sharp change in viscosity drop and moderate additive depletion when viscosity index of hydraulic oil is very high. For the extension of hydraulic fluid life, it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Performance of newly developed hydraulic oil based on used oil analysis is compared with previously used one. The properties of new formulation are the viscosity index of 140 and improved thermal stability consists of VHVI base oil. Field test results showed the possibility of extension of fluid life. Additionally, for development of high performance product, new required propertied and performances were discussed.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.390-393
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• 2002

Many researchers have studied for the barrier liner in the landfill that is mixed with clay mineral, native soils and solidified agent. However, they have a littel but problems for safety construction and maintenance as a bottom liner systems in the landfill. In this paper the authors studied the effects on hydraulic conductivity by electric-chemical ion-exchange agent that is a soil stabilization agent(Sulphonated Oil), The application of the soil stabilization agent to meet the hydraulic conductivity of clay liner in landfill is possible if the additive quantity and a proper reaction time is determined relevantly in the laboratory test.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 Lecture Notes by Two Distinguished Scholars
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• pp.1.1-16
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• 1997

This lecture summarizes the progress of the development of the different ground improvement techniques in Bangkok Plain and is reviewed in relation to the extensive deep wen pumping and the resulting piezometric drawdown at deeper depths. Case records of test embankments with sand drains, sand wicks and PVD are presented to inustrate the effectiveness of different types of vertical drains with surcharge. The use of prefsbicated drain seems more superior than the other types of sand drain. Construction of test embaxlkment, criteria for PVD selection and relevant laboratory testing techniques are discussed for formulating the specif'ication. Alternative teckuuque, such in, the use of deep chemical mixing is reviewed in terms of the efficiency of cement, lime and flyash as additive. Vacuum pre-loading with surcharge and elctro- osmotic consolidation are also explored as possible tectmiques to improve the engineering properties of soft Bangkok clay.

• Journal of Communications and Networks
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• 제7권1호
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• pp.13-20
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• 2005

In this paper, a new multi carrier, direct sequence code division multiple access (MC-DS-CDMA) system is proposed. Our new signal construction is based on convolutional encoding of the transmitted data, serial-to-parallel (S/P) conversion of the encoded data, Walsh-Hadamard-transformation (WHT), a second S/P conversion of the WHT outputs, spread spectrum (SS) modulation with a common pseudo-noise (PN) sequence, and then multicarrier transmission. The system bit error rate (BER) performance in frequency selective fading channel in the presence of additive white Gaussian noise (AWGN) and a jamming tone is analyzed and simulated. The numerical results are compared with those from an orthogonal MC-DS-CDMA system of Sourour and Nakagawa [7]. It is shown that the two systems have almost the same BER performance, but the proposed scheme has better anti-jamming ability.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2001년도 춘계학술발표논문집 (상)
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• pp.375-378
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• 2001

본 논문에서는 선형 MACA의 0-트리의 한 경로를 기본 경로로 하여 나머지 다른 트리를 구성하고 여원벡터를 선형 MACA의 하나의 상태로 해석하였을 때 상태전이그래프에서 놓이는 위치에 따라 선형 MACA로부터 유도된 여원을 갖는 CA의 모든 트리를 구성하는 알고리즘을 제안한다. 주어진 전이행렬과 여원벡터를 가지는 additive CA의 트리를 구성함에 있어 보다 빠르게 구성할 수 있는 알고리즘을 제시한다.

• Advances in concrete construction
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• 제8권3호
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• pp.199-206
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• 2019

High performance sandcretes (HPS) are new concretes characterized by particles having a diameter less than 5 mm, as well as very high mechanical strength and durability. This work consists in finding solutions to make sandcretes with good physico-mechanical and durability properties for this new generation of micro-concrete. However, upgrading ordinary sandcrete into high performance sandcrete (HPS) requires a thorough study of formulation parameters (equivalent water/binder ratio, type of cement and its dosage, kind and amount of super plasticizer, and gravel/sand ratio). This research study concerns the formulation, characterization and durability, in a sulphate environment, of a high performance sandcrete (HPS), made from local materials. The obtained results show that the rheological properties of fresh concrete and mechanical strength differ with the mineralogy, density and grain size distribution of sands and silica fume used.

• Geomechanics and Engineering
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• 제34권4호
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• pp.425-435
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• 2023

Granite and marble are widely produced and utilized in the construction industry, resulting in significant waste production. It is essential to manage this waste appropriately and repurpose it in recycling processes to ensure sustainability. The utilization of waste materials such as marble and granite waste (MGW) has become increasingly important in geotechnical engineering to improve the physical and mechanical properties of weak soils. This study investigated the applicability of utilizing MGW and cement (C)-MGW mixtures to improve clayey soil. A series of model plate loading tests were carried out in a specialized circular test tank to assess the influence of MGW and C-MGW mixing ratios on clayey soil samples. The samples were prepared by blending MGW and C-MGW in predetermined proportions. It is found that the bearing capacity of clay soil increased by approximately 71% when using MGW and C additives. Moreover, the consolidated settlement values of the clay soil decreased up to 6 times compared to the additive-free case.

• 대한교통학회지
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• 제34권6호
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• pp.570-579
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• 2016

Stepwise 환승계수(이하 STC)는 환승회수 증가에 따라 환승비용을 실제보다 많게 인식하도록 한다. 통행시간과 최소환승회수 정보를 제공하는 것은 이러한 경향을 감안하는 취지이다. STC가 포함된 경로탐색문제는 비가산성비용을 포함하며 최적조건의 비성립으로 경로열거가 요구된다. 따라서 대중교통망에서 STC를 고려하는 경로탐색에 대한 이론적 검토를 통해서 경로탐색의 실패를 우회하는 방안이 요구된다. 본 연구는 STC가 포함되는 대중교통망에서 확률적 통행배정모형에 대하여 검토한다. 비가산성 경로문제를 완화하는 방안으로 유입링크기반 전체경로삭제기법을 활용하는 방안을 제안한다. 전체경로삭제기법은 출발지에서 도착지까지 서로 상이한 경로의 구성된 가능경로집합을 구축하기 용이하다. STC를 반영한 경로기반 Logit 모형을 대중교통통행배정기법으로 구축한다.

• 한국구조물진단유지관리공학회 논문집
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• 제24권5호
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• pp.143-149
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• 2020

본 연구에서는 금속 적층 제조로 출력한 격자 구조체의 내부 공극에 반응성 아크릴 화합물을 충진시켜, 밀도 제어가 가능한 밀실 복합 격자 구조체를 제작하는 것을 목표로 한다. 또한 본 격자 구조체를 건설분야에 적용하기 위하여 반응성 아클릴 화합물에 보통 포틀랜드 시멘트를 첨가함으로써 콘크리트와의 부착성능을 향상시킨 부착력 증진 반응성 아크릴 화합물을 검토하였다. 최종적으로 제조한 부착력 증진 반응성 아크릴 화합물을 격자 구조체 내부에 충진하여 밀도 제어형 기능성 복합 격자 구조체(Hybrid Lattice structure)의 비중, 흡수율 및 부착강도를 검토하였다. 그 결과, 밀도 제어 가능, 흡수율 1.0 % 이하 및 재령 1일 부착강도 1.78 MPa ~ 1.98 MPa의 결과물을 도출하였다.