• Title/Summary/Keyword: Spencer method

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A Review of the Characteristics of Early Apparatus and Methods for Hemoglobin Estimation (Hemoglobin 평가를 위한 초기 기구의 특성 및 측정법 고찰)

  • Kwon, Young-Il
    • Korean Journal of Clinical Laboratory Science
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    • v.48 no.4
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    • pp.401-410
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    • 2016
  • Since the late 19th century, scientific logic and techniques have been used extensively in the field of clinical pathology, including many laboratory tests utilizing various apparatuses and instruments. Among the techniques to measure hemoglobin, the visual color comparison method was most popular around this time; the specific gravity method and gasometric method were not widely adopted. Instruments that use the visual color comparison method include Gowers' hemoglobinometer, von Fleischl's hemoglobinometer, Dare's hemoglobinometer, Oliver's hemoglobinometer, Haden-Hausser hemoglobinometer, and Spencer Hb meter. Initially, the visual color comparison methods were used to diluate and hemolyze blood with distilled water and then to measure its color. Later, these methods were further developed to measure hemoglobin without dilution, and improved with the formation of acid or alkaline hematin ensuring the stability of color development. Hammerschlag's method as well as the Schmaltz and Peiper's methods were based on specific gravity measurement, but they were not widely used. The gasometric method used the Van Slyke gasometer, indirectly measuring the hemoglobin concentration. This method provides the most accurate results. This survey examined the characteristics and limitations of hemoglobinometers and methods used to measure hemoglobin from the late 19th century to the early-and mid-20th century. Moreover, this study aims to improve the understanding and applicability of the current methods and emerging technologies used in measuring hemoglobin. It is also expected that this investigation is the starting point to promote awareness of the need to organize historical data for a variety of historical relics of the diagnostic laboratory tests.

A Study on Used Colors Characteristic of Case Study for Children Play Therapy Center (국내.외 놀이치료 시설의 사례분석을 통한 사용 색채 특성에 관한 연구)

  • Choi, Jin-Hee
    • Korean Institute of Interior Design Journal
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    • v.20 no.4
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    • pp.29-36
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    • 2011
  • This study aims to be the useful resources for selecting play therapy facility in the future by analysis of used colors in the play therapy facility as the subsequent studies of the thesis of KIID in 2010, titled 'Study on the planning factors of case study for children's play therapy center'. As research method of this study, the overall understanding about play therapy facility was improved through theoretical considerations, and it was about the Moon-Spencer's theory of color harmony which will be used for the framework of case study. In Section 3, the field trips at 6 facilities were conducted as the case research and the data research through website was conducted for case study. Moon-Spencer's theory of color harmony used the Munsell's color Order System, so after measuring CMYK value of the picture for the case research through photo shop, the color, brightness and saturation were measured through Munsell Conversion program. The following three kinds of features were drawn by research of the harmony and disharmony of used colors for the cases after substituting the theory of color harmony through the measured color. brightness, and saturation. First. series Y and YR were used mainly for warm image as the concept of play therapy room. Second, the various colors were used for comfortable image like home. But the various patterns were used by mixing for the therapy room F, so it gives confusing impression. Third, series YR and achromatic color as the color of wood were used unavoidably for using materials of manufactured goods.

A Document-Driven Method for Certifying Scientific Computing Software for Use in Nuclear Safety Analysis

  • Smith, W. Spencer;Koothoor, Nirmitha
    • Nuclear Engineering and Technology
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    • v.48 no.2
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    • pp.404-418
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    • 2016
  • This paper presents a documentation and development method to facilitate the certification of scientific computing software used in the safety analysis of nuclear facilities. To study the problems faced during quality assurance and certification activities, a case study was performed on legacy software used for thermal analysis of a fuelpin in a nuclear reactor. Although no errors were uncovered in the code, 27 issues of incompleteness and inconsistency were found with the documentation. This work proposes that software documentation follow a rational process, which includes a software requirements specification following a template that is reusable, maintainable, and understandable. To develop the design and implementation, this paper suggests literate programming as an alternative to traditional structured programming. Literate programming allows for documenting of numerical algorithms and code together in what is termed the literate programmer's manual. This manual is developed with explicit traceability to the software requirements specification. The traceability between the theory, numerical algorithms, and implementation facilitates achieving completeness and consistency, as well as simplifies the process of verification and the associated certification.

Stochastic DLV method for steel truss structures: simulation and experiment

  • An, Yonghui;Ou, Jinping;Li, Jian;Spencer, B.F. Jr.
    • Smart Structures and Systems
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    • v.14 no.2
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    • pp.105-128
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    • 2014
  • The stochastic damage locating vector (SDLV) method has been studied extensively in recent years because of its potential to determine the location of damage in structures without the need for measuring the input excitation. The SDLV method has been shown to be a particularly useful tool for damage localization in steel truss bridges through numerical simulation and experimental validation. However, several issues still need clarification. For example, two methods have been suggested for determining the observation matrix C identified for the structural system; yet little guidance has been provided regarding the conditions under which the respective formulations should be used. Additionally, the specific layout of the sensors to achieve effective performance with the SDLV method and the associated relationship to the specific type of truss structure have yet to be explored. Moreover, how the location of truss members influences the damage localization results should be studied. In this paper, these three issues are first investigated through numerical simulation and subsequently the main results are validated experimentally. The results of this paper provide guidance on the effective use of the SDLV method.

Feedforward actuator controller development using the backward-difference method for real-time hybrid simulation

  • Phillips, Brian M.;Takada, Shuta;Spencer, B.F. Jr.;Fujino, Yozo
    • Smart Structures and Systems
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    • v.14 no.6
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    • pp.1081-1103
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    • 2014
  • Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.

Real-time hybrid testing using model-based delay compensation

  • Carrion, Juan E.;Spencer, B.F. Jr.
    • Smart Structures and Systems
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    • v.4 no.6
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    • pp.809-828
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    • 2008
  • Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.

Optimized finite element model updating method for damage detection using limited sensor information

  • Cheng, L.;Xie, H.C.;Spencer, B.F. Jr.;Giles, R.K.
    • Smart Structures and Systems
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    • v.5 no.6
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    • pp.681-697
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    • 2009
  • Limited, noisy data in vibration testing is a hindrance to the development of structural damage detection. This paper presents a method for optimizing sensor placement and performing damage detection using finite element model updating. Sensitivity analysis of the modal flexibility matrix determines the optimal sensor locations for collecting information on structural damage. The optimal sensor locations require the instrumentation of only a limited number of degrees of freedom. Using noisy modal data from only these limited sensor locations, a method based on model updating and changes in the flexibility matrix successfully determines the location and severity of the imposed damage in numerical simulations. In addition, a steel cantilever beam experiment performed in the laboratory that considered the effects of model error and noise tested the validity of the method. The results show that the proposed approach effectively and robustly detects structural damage using limited, optimal sensor information.

A Study on In-Situ Slope Reinforcement Methods Using Nailed Geotextiles (네일 및 지오텍스타일을 이용한 원위치 사면보강공법에 관한 연구)

  • 김홍택
    • Geotechnical Engineering
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    • v.10 no.4
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    • pp.133-152
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    • 1994
  • In the present study, an economic design of Anchored Geosynthetic(AG) System applied mainly to reinforce unstable soil slopes is investigated. For this purpose methods of stability analysis are developed to determine the optimum installation angle, required minimum length and maximum spacing of nails. Anchorage of nails within the soil mass is achieved by frictional resistance to pull out along the effective length of the nails. Cases of infinite slope and finite slope are dealt with individually. Silce methods of stability analysis developed in the present study are limit-equilibrium-based. For the case of finite slope Spencer method which considers interslice force is modified to evalyate the overall stability. In addition, the effects of various design parameters on requried length and spacing of nails corresponding to the optimum orientation of nails are analyzed. Based on the analysis, a simplified equation is given for the optimum nail orientation. Also the importance of optimum nail orientation is illustrated throughout design example, and the appropriateness of judgment criterion are examined.

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Experimental verification of a distributed computing strategy for structural health monitoring

  • Gao, Y.;Spencer, B.F. Jr.
    • Smart Structures and Systems
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    • v.3 no.4
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    • pp.455-474
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    • 2007
  • A flexibility-based distributed computing strategy (DCS) for structural health monitoring (SHM) has recently been proposed which is suitable for implementation on a network of densely distributed smart sensors. This approach uses a hierarchical strategy in which adjacent smart sensors are grouped together to form sensor communities. A flexibility-based damage detection method is employed to evaluate the condition of the local elements within the communities by utilizing only locally measured information. The damage detection results in these communities are then communicated with the surrounding communities and sent back to a central station. Structural health monitoring can be done without relying on central data acquisition and processing. The main purpose of this paper is to experimentally verify this flexibility-based DCS approach using wired sensors; such verification is essential prior to implementation on a smart sensor platform. The damage locating vector method that forms foundation of the DCS approach is briefly reviewed, followed by an overview of the DCS approach. This flexibility-based approach is then experimentally verified employing a 5.6 m long three-dimensional truss structure. To simulate damage in the structure, the original truss members are replaced by ones with a reduced cross section. Both single and multiple damage scenarios are studied. Experimental results show that the DCS approach can successfully detect the damage at local elements using only locally measured information.

Design formulas for vibration control of taut cables using passive MR dampers

  • Duan, Yuanfeng;Ni, Yi-Qing;Zhang, Hongmei;Spencer, Billie.F. Jr.;Ko, Jan-Ming;Fang, Yi
    • Smart Structures and Systems
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    • v.23 no.6
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    • pp.521-536
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    • 2019
  • Using magnetorheological (MR) dampers in multiswitch open-loop control mode has been shown to be cost-effective for cable vibration mitigation. In this paper, a method for analyzing the damping performance of taut cables incorporating MR dampers in open-loop control mode is developed considering the effects of damping coefficient, damper stiffness, damper mass, and stiffness of the damper support. Making use of a three-element model of MR dampers and complex modal analysis, both numerical and asymptotic solutions are obtained. An analytical expression is obtained from the asymptotic solution to evaluate the equivalent damping ratio of the cable-damper system in the open-loop control mode. The individual and combined effects of the damping coefficient, damper stiffness, damper mass and stiffness of damper support on vibration control effectiveness are investigated in detail. The main thrust of the present study is to derive a general formula explicitly relating the normalized system damping ratio and the normalized damper parameters in consideration of all concerned effects, which can be easily used for the design of MR dampers to achieve optimal open-loop vibration control of taut cables.