• Title, Summary, Keyword: Deng(2007)

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Applications of fiber optic sensors in civil engineering

  • Deng, Lu;Cai, C.S.
    • Structural Engineering and Mechanics
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    • v.25 no.5
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    • pp.577-596
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    • 2007
  • Recent development of fiber optic sensor technology has provided an excellent choice for civil engineers for performance monitoring of civil infrastructures. Fiber optic sensors have the advantages of small dimensions, good resolution and accuracy, as well as excellent ability to transmit signal at long distances. They are also immune to electromagnetic and radio frequency interference and may incorporate a series of interrogated sensors multiplexed along a single fiber. These advantages make fiber optic sensors a better method than traditional damage detection methods and devices to some extent. This paper provides a review of recent developments in fiber optic sensor technology as well as some applications of fiber optic sensors to the performance monitoring of civil infrastructures such as buildings, bridges, pavements, dams, pipelines, tunnels, piles, etc. Existing problems of fiber optic sensors with their applications to civil structural performance monitoring are also discussed.

Sliding mode control based on neural network for the vibration reduction of flexible structures

  • Huang, Yong-An;Deng, Zi-Chen;Li, Wen-Cheng
    • Structural Engineering and Mechanics
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    • v.26 no.4
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    • pp.377-392
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    • 2007
  • A discrete sliding mode control (SMC) method based on hybrid model of neural network and nominal model is proposed to reduce the vibration of flexible structures, which is a robust active controller developed by using a sliding manifold approach. Since the thick boundary layer will reduce the virtue of SMC, the multilayer feed-forward neural network is adopted to model the uncertainty part. The neural network is trained by Levenberg-Marquardt backpropagation. The design objective of the sliding mode surface is based on the quadratic optimal cost function. In course of running, the input signal of SMC come from the hybrid model of the nominal model and the neural network. The simulation shows that the proposed control scheme is very effective for large uncertainty systems.

Tension and impact behaviors of new type fiber reinforced concrete

  • Deng, Zongcai;Li, Jianhui
    • Computers and Concrete
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    • v.4 no.1
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    • pp.19-32
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    • 2007
  • This paper is concentrated on the behaviors of five different types of fiber reinforced concrete (FRC) in uniaxial tension and flexural impact. The complete stress-strain responses in tension were acquired through a systematic experimental program. It was found that the tensile peak strains of concrete with micro polyethylene (PEF) fiber are about 18-31% higher than that of matrix concrete, those for composite with macro polypropylene fiber is 40-83% higher than that of steel fiber reinforced concrete (SFRC). The fracture energy of composites with micro-fiber is 23-67% higher than that of matrix concrete; this for macro polypropylene fiber and steel fiber FRCs are about 150-210% and 270-320% larger than that of plain concrete respectively. Micro-fiber is more effective than macro-fiber for initial crack impact resistance; however, the failure impact resistance of macro-fiber is significantly larger than that of microfiber, especially macro-polypropylene-fiber.

Mechanical behaviors of concrete combined with steel and synthetic macro-fibers

  • Deng, Zongcai;Li, Jianhui
    • Computers and Concrete
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    • v.4 no.3
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    • pp.207-220
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    • 2007
  • In this paper, hybrid fibers including high elastic modulus steel fiber and low elastic modulus synthetic macro-fiber (HPP) as two elements were used as reinforcement materials in concrete. The flexural toughness, flexural impact and fracture performance of the composites were investigated systematically. Flexural impact strength was analyzed with statistic analyses method; based on ASTM and JSCE method, an improved flexural toughness evaluating method suitable for concrete with synthetic macro-fiber was proposed herein. The experimental results showed that when the total fiber volume fractions ($V_f^a$) were kept as a constant ($V_f^a=1.5%$), compared with single type of steel or HPP fibers, hybrid fibers can significantly improve the toughness, flexural impact life and fracture properties of concrete. Relative residual strength RSI', impact ductile index ${\lambda}$ and fracture energy $G_F$ of concrete combined with hybrid fibers were respectively 66-80%, 5-12 and 121-137 N/m, which indicated that the synergistic effects (or combined effects) between steel fiber and synthetic macro-fiber were good.

Classification Rule for Optimal Blocking for Nonregular Factorial Designs

  • Park, Dong-Kwon;Kim, Hyoung-Soon;Kang, Hee-Kyoung
    • Communications for Statistical Applications and Methods
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    • v.14 no.3
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    • pp.483-495
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    • 2007
  • In a general fractional factorial design, the n-levels of a factor are coded by the $n^{th}$ roots of the unity. Pistone and Rogantin (2007) gave a full generalization to mixed-level designs of the theory of the polynomial indicator function using this device. This article discusses the optimal blocking scheme for nonregular designs. According to hierarchical principle, the minimum aberration (MA) has been used as an important criterion for selecting blocked regular fractional factorial designs. MA criterion is mainly based on the defining contrast groups, which only exist for regular designs but not for nonregular designs. Recently, Cheng et al. (2004) adapted the generalized (G)-MA criterion discussed by Tang and Deng (1999) in studying $2^p$ optimal blocking scheme for nonregular factorial designs. The approach is based on the method of replacement by assigning $2^p$ blocks the distinct level combinations in the column with different blocks. However, when blocking level is not a power of two, we have no clue yet in any sense. As an example, suppose we experiment during 3 days for 12-run Plackett-Burman design. How can we arrange the 12-runs into the three blocks? To solve the problem, we apply G-MA criterion to nonregular mixed-level blocked scheme via the mixed-level indicator function and give an answer for the question.

Evaluating Service System Alternatives via a Computer Simulation-enabled MCDM Framework

  • Deng, Wei-Jaw;Pei, Wen;Tsai, Chih-Hung
    • International Journal of Quality Innovation
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    • v.8 no.2
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    • pp.100-114
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    • 2007
  • Decision makers in the service industry must effectively cope with queuing problems, service capacity optimization, service efficiency and service quality problems. This study proposes a computer simulation-enabled MCDM framework that integrates computer simulation analysis, Taguchi method, expert opinion and multiple criteria decision making (MCDM) to assist decision makers in coping with decision problems. In this framework, Taguchi method is adopted to reduce the time required for the simulation experiment. Computer simulation analysis is adopted to obtain useful information for rapid decision-making without interrupting actual production. MCDM is used to select the optimal alternative. The illustrative result is extremely promising.

Urban Culture Construction in Modern Landscape Architecture;Take the Design of South Bank Linear Park in Meizhou City, Guangdong Province as an Example

  • Wugong, Deng;Jianzhong, Jia;Bingyue, Han
    • Proceedings of the Korean Institute of Landscape Architecture Conference
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    • pp.30-37
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    • 2007
  • Modern cities are weak in traditional culture with the lack of characteristics and the problem of environmental deterioration. As the important carrier of urban culture, landscape architecture should be responsible for solving these problems. The urban need is paid much attention in the design of South Bank Linear Park in Meizhou city. Following the principle of inheriting and developing urban traditional culture, the design of the whole park is integrated with Hakka culture in Meizhou, which forms the landscape with local features and modern landscape architecture culture, and promotes the urban culture construction.

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Comparison between Traditional IPA and Revised IPA; The Suncheon Bay Wetland Reserve (전통적 IPA(Importance-Performance Analysis)와 수정된 IPA의 비교연구; 순천만 습지를 대상으로)

  • Kim, Bo-Mi;Lee, Dong-Kun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.45 no.2
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    • pp.40-50
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    • 2017
  • Compared to the traditional format, the revised IPA is an effective method for selecting a management strategy as compared to the traditional IPA. Comparison between the traditional IPA and revised IPA with a management strategy has been, however, limited. Therefore, the difference between the traditional IPA and revised IPA was compared to select an effective management strategy in the Suncheon Bay Wetland Reserve. First of all, related papers were reviewed to select an appropriate revised IPA. It was found that Deng (2007)'s revised IPA was appropriate for quantifying service quality and a management strategy that affects the measurable satisfaction of visitors in the space. Second, the results of the traditional IPA were compared with the revised IPA in the Suncheon Bay Wetland Reserve and the management strategy of the revised IPA and the changes of management factors were discussed. It was found that some management factors deviated from the order of the quadrant "low priority for managers", "Concentrate management here", "Keep up the good work" were moved to the order of the quadrants "Concentrate management here", "low priority for managers" and "Possible overkill" in the revised IPA grid. The complexity as a management factor resulted in higher demand management than the traditional IPA, which moved from "low priority for managers" to "Concentrate management here". Management factors resulted in lower demand management than the traditional IPA moved from "Concentrate management here" to "low priority for managers"; these consisted of shade trees, exhibition exteriors, programs, and a guided tour. Also, management factors moved from "Keep up the good work" to "Possible overkill" consisted of relaxation facilities, glow of the setting sun, a hedge, and an exhibition interior. Over all, the revised IPA responded properly to changes in the measurable satisfaction of visitors to the Suncheon Bay Wetland Reserve. Therefore, a revised IPA should be provided for accurate and reliable guidelines when decision makers establish management strategies.

Feature Voting for Object Localization via Density Ratio Estimation

  • Wang, Liantao;Deng, Dong;Chen, Chunlei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.12
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    • pp.6009-6027
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    • 2019
  • Support vector machine (SVM) classifiers have been widely used for object detection. These methods usually locate the object by finding the region with maximal score in an image. With bag-of-features representation, the SVM score of an image region can be written as the sum of its inside feature-weights. As a result, the searching process can be executed efficiently by using strategies such as branch-and-bound. However, the feature-weight derived by optimizing region classification cannot really reveal the category knowledge of a feature-point, which could cause bad localization. In this paper, we represent a region in an image by a collection of local feature-points and determine the object by the region with the maximum posterior probability of belonging to the object class. Based on the Bayes' theorem and Naive-Bayes assumptions, the posterior probability is reformulated as the sum of feature-scores. The feature-score is manifested in the form of the logarithm of a probability ratio. Instead of estimating the numerator and denominator probabilities separately, we readily employ the density ratio estimation techniques directly, and overcome the above limitation. Experiments on a car dataset and PASCAL VOC 2007 dataset validated the effectiveness of our method compared to the baselines. In addition, the performance can be further improved by taking advantage of the recently developed deep convolutional neural network features.