• 제목/요약/키워드: FDB

검색결과 49건 처리시간 0.027초

Ensemble techniques and hybrid intelligence algorithms for shear strength prediction of squat reinforced concrete walls

  • Mohammad Sadegh Barkhordari;Leonardo M. Massone
    • Advances in Computational Design
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    • 제8권1호
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    • pp.37-59
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    • 2023
  • Squat reinforced concrete (SRC) shear walls are a critical part of the structure for both office/residential buildings and nuclear structures due to their significant role in withstanding seismic loads. Despite this, empirical formulae in current design standards and published studies demonstrate a considerable disparity in predicting SRC wall shear strength. The goal of this research is to develop and evaluate hybrid and ensemble artificial neural network (ANN) models. State-of-the-art population-based algorithms are used in this research for hybrid intelligence algorithms. Six models are developed, including Honey Badger Algorithm (HBA) with ANN (HBA-ANN), Hunger Games Search with ANN (HGS-ANN), fitness-distance balance coyote optimization algorithm (FDB-COA) with ANN (FDB-COA-ANN), Averaging Ensemble (AE) neural network, Snapshot Ensemble (SE) neural network, and Stacked Generalization (SG) ensemble neural network. A total of 434 test results of SRC walls is utilized to train and assess the models. The results reveal that the SG model not only minimizes prediction variance but also produces predictions (with R2= 0.99) that are superior to other models.

HDD용 유체동압베어링 성능평가 시스템 설계 및 동적거동 측정 (Design of Performance Evaluation System and Measurement of Dynamic Behavior for Fluid Hydrodynamic Bearing in HDD)

  • 강정우;이태휘;이형욱;박성준
    • 한국정밀공학회지
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    • 제28권10호
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    • pp.1159-1165
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    • 2011
  • The recording density of HDD is increasing in ratio of 100% each year. Because the increasing of recording density requires the feature of high rotation, fixation and low-noise, fluid hydrodynamic bearing(FDB) has been paid attention to overcome a limitation in ball bearing. Most of researches related to improving performance of FDB have been studied in Japan which has 80% more market share of HDD spindle motor assembly. Main subject of studies are about for the design of the groove shape, manufacturing process of fluid dynamic bearing, performance evaluation and measurement. In HDD, non-repeatable runout(NRRO) is most important parameter which determines the performance of HDD spindle system because NRRO is unpredictable that cannot be compensated in head/slider servo system. In this study, performance evaluation system can measure dynamic behaviors were designed and methodology for calculating imbalance, RRO, and NRRO were proposed.

CORBA 기반의 CALS 통합 데이터베이스 설계 (A CALS Integrated Database Design Utilizing CORBA)

  • 우훈식;정석찬
    • 한국전자거래학회지
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    • 제2권2호
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    • pp.155-169
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    • 1997
  • The CALS integrated database is a key information technology in which CALS implements an information sharing system to enable digital data transfers for technical and non-technical information in distributed and heterogeneous environments. Such heterogeneously distributed CALS information needs to be systematically incorporated so that it can provide a global data view for CALS users. In this paper, we investigated the technologies of CALS integrated database, and proposed a system prototype to implement an integrated data environment (IDE) utilizing distributed object environments CORBA (Common Object Request Broker Architecture).

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Development of High Performance Multi-lobe Fluid Dynamic Bearings Using a Sintered Material

  • Tokushima, Hidekazu
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.379-380
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    • 2006
  • Recently, in spindle motors for hard disk drive (HDD) devices, fluid dynamic bearings (FDB) with herringbone grooves have come to be used instead of ball bearings due to the demand for high density recording of the devices etc. In this study, a 5-lobe bearing with high bearing stiffness using a sintered material was developed, and the bearing performance was examined by simulated calculations and experiments. As a result, it was clarified that the 5-lobe bearing had the required performance for practical use in the spindle motor for HDD

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Fragrance Composition in Six Tree Peony Cultivars

  • Zhao, Jing;Hu, Zeng-Hui;Leng, Ping-Sheng;Zhang, Hui-Xiu;Cheng, Fang-Yun
    • 원예과학기술지
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    • 제30권6호
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    • pp.617-625
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    • 2012
  • Tree peony is a traditional famous flower of China, and plays an important role in Chinese traditional culture. But the floral scent of tree peony in vivo is little known. In this study, in order to explore the floral composition of tree peony, floral volatiles of six cultivars, including Paeonia suffruticosa 'Zhaofen' (ZF), P. suffruticosa 'Luoyanghong' (LYH), P. ostii 'Fengdanbai' (FDB), P. ${\times}$ lemonei 'High noon' (HN), P. ${\times}$ lemonei 'Renown' (R), and P. rockii 'Gaoyuanshenghuo' (GYSH) were collected by dynamic headspace and then identified by Automated Thermal Desorption-Gas Chromatography/Mass Spectometry. The results showed that floral fragrances of the six cultivars were qualitatively and quantitatively distinct. A total of 105 volatiles involving ten categories were detected. But not all volatile categories were emitted from these cultivars. The six peony cultivars emitted some shared compounds and peculiar compounds. The total released amounts of volatiles emitted from six cultivars were found significantly different, which was greatest for 'GYSH'. The most abundant volatile compounds detected from 'ZF', 'LYH', 'FDB', 'HN', 'R', and 'GYSH' were respectively ${\alpha}$-pinene, 2,3-dihydroxy propanal, 3-methyl-1-butanol, 2-ethyl-1-hexanol, acetic acid 1-methylethyl ester, and 5-ethyl-2,2,3-trimethyl heptane. This result may contribute to exploring the biosynthesis and emission mechanism of floral scent in tree peony.

공개된 토지피복도를 활용한 위성영상 분류 (Image Classification for Military Application using Public Landcover Map)

  • 홍우용;박완용;송현승;정철훈;어양담;김성준
    • 한국군사과학기술학회지
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    • 제13권1호
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    • pp.147-155
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    • 2010
  • Landcover information of access-denied area was extracted from low-medium and high resolution satellite image. Training for supervised classification was performed to refer visually by landcover map which is made and distributed from The Ministry of Environment. The classification result was compared by relating data of FACC land classification system. As we rasterize digital military map with same pixel size of satellite classification, the accuracy test was performed by image to image method. In vegetation case, ancillary data such as NDVI and image for seasons are going to improve accuracy. FACC code of FDB need to recognize the properties which can be automated.

이동 평균 방법을 이용한 4배속 스핀들 모터의 제어 성능 향상 방법 (A 4X Spin Control Method with Moving Average for Improvement of Control Accuracy in HDD)

  • 김진석;오경환;이병국
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2010년도 추계학술대회
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    • pp.329-330
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    • 2010
  • 과거 볼베어링을 이용하던 하드 디스크 드라이브(HDD: Hard Disk Drive)의 스핀들 모터는 유체 동역학 베어링(FDB: Fluid Dynamic Bearing) 장착으로 저전력 소비 및 고속 구동이 가능하게 되었다. 하드 디스크 드라이브에서 스핀들 모터의 제어는 주된 읽기 쓰기 동작을 위한 가장 기본적인 제반 여건이며, 단위 면적당 데이터(BPI)가 증가함에 따라서 스핀들 모터의 제어 성능은 드라이브 성능과 직결되는 더욱 중요한 인자중의 하나가 되었다. 본 논문에서는 스핀들 모터의 샘플링 주기를 기존 대비 4배 증가하여 제어 성능 향상하는 4배속 스핀들 모터 제어 방법을 제시하고 있다.

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쑥을 첨가한 곤약국수의 제조 및 특성 (Preparation and Characteristics of Konjac Noodle-added Mugwort)

  • 김석지
    • 동아시아식생활학회지
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    • 제23권5호
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    • pp.613-619
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    • 2013
  • 본 연구는 저칼로리 식품으로 알려져 있는 곤약과 약리작용이 뛰어난 쑥을 첨가한 곤약국수를 제조하고자 쑥의 건조방법에 따른 색도 변화와 곤약분말 농도, pH, 응고제의 종류에 따른 곤약 겔의 제조조건과 쑥의 첨가량에 따른 최적의 곤약국수의 제조방법을 조사하였다. 곤약국수에 사용할 쑥의 건조방법별 색도 변화 조사 결과, 1% $NaHCO_3$ 용액에 데친 후 건조한 방법(HADB, FDB)은 데치지 않은 방법(HAD, FD)에 비하여 쑥의 녹색유지에 효과적이었고 데친 후 동결건조한 방법(FDB)은 데친 후 열풍건조한 방법(HADB)에 비하여 선명한 녹색을 띄고 있었다. 따라서 쑥 가공처리에 있어서 1% $NaHCO_3$ 알칼리 용액에 데친 후, 동결건조방법이 쑥의 녹색을 유지하는데 가장 효과적이었다. 곤약 겔의 최적의 제조조건을 조사하고자 곤약분말의 농도, pH, 응고제의 종류에 따른 곤약 겔의 물성(견고성, 탄력성, 응집성, 점착성)을 측정하였으며, 그 결과, 분말농도는 9%, pH는 12, 응고제는 $Na_3PO_4$를 사용했을 때 물성치가 우수하게 나타났다. 쑥의 첨가량의 영향을 분석한 결과, 곤약분말에 대하여 1.5% 첨가가 색, 향, 맛 등 전반적인 기호도가 높게 나타나, 1.5% 첨가하는 것이 바람직할 것으로 판단되었다. 이상의 결과로부터 제시한 곤약의 제조 방법과 적절한 농도의 쑥을 첨가한 곤약국수를 제조하여 영양적, 물성적, 관능적으로 소비자들에게 긍정적인 반응을 보일 수 있는 제품이 제조될 수 있는 기초자료로 활용될 수 있다고 사료된다.

천공형 티타늄막을 이용한 골유도재생술 시 수종의 골이식재가 골재생에 미치는 영향 (Effect of bone graft materials on bone formation in guided bone regeneration using perforated titanium membrane)

  • 홍승범;권영혁;박준봉;허익;정종혁
    • Journal of Periodontal and Implant Science
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    • 제36권1호
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    • pp.223-237
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    • 2006
  • The purpose of the present study was to evaluate the effect of bone graft materials including deproteinized bovine bone(DBB), demineralized freeze-dried bone(DFDB), freeze-dried bone(FDB) on bone formation in guided bone regeneration using perforated titanium membrane(TM). 16 adult male rabbits(mean BW 2kg) were used in this study and 4 rabbits allotted to each test group. Intramarrow penetration(diameter 6.5mm) was done with round carbide bur on calvaria to promote blood supply and clot formation in the wound area. The test groups were devided into 4 groups as follows: TM only(test 1), TM +DBB(test 2), TM +DFDB(test 3), TM +FDB(test 4). Perforated titanium membrane was contoured in rectangular parallelepiped shape(0.5mm pore diameter, 10mm in one side, 2mm in inner height), filled the each graft material and placed on the decorticated carvaria. Perforated titanium membrane was fixed with resorbable suture materials. The animals were sacrificed at 2, 8 weeks after the surgery. Non-decalcified preparations were routinely processed for histologic analysis. The results of this study were as follows: 1. Perforated titanium membrane was biocompatible. 2. Perforated titanium membrane had capability of maintaining the space during the healing period but invasion of soft tissue through the perforations of titanium membrane decreased the space available for bone formation. 3. In test 1 group without bone graft material, the amount of bone formation and bone maturation was better than other test groups. 4. Among the graft materials, the effect of freeze-dried bone on bone formation was best. 5. In the test groups using deproteinized bovine bone, demineralized freeze-dried bone, bone formation was a little. The spacemaking capability of the membrane may be crucial for bone formation. The combined treatment with the perforated titanium membrane and deproteinized bovine bone or demineralized freeze-dried bone failed to demonstrate any added effect in the bone formation. Minimization of size and numbers of perforations of titanium membrane or use of occlusive titanium membrane might be effective to acquire predictable results in the vertical bone formation.