• Title/Summary/Keyword: Kaiser effect

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A Training Intervention for Supervisors to Support a Work-Life Policy Implementation

  • Laharnar, Naima;Glass, Nancy;Perrin, Nancy;Hanson, Ginger;Anger, W. Kent
    • Safety and Health at Work
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    • v.4 no.3
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    • pp.166-176
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    • 2013
  • Background: Effective policy implementation is essential for a healthy workplace. The Ryan-Kossek 2008 model for work-life policy adoption suggests that supervisors as gatekeepers between employer and employee need to know how to support and communicate benefit regulations. This article describes a workplace intervention on a national employee benefit, Family and Medical Leave Act (FMLA), and evaluates the effectiveness of the intervention on supervisor knowledge, awareness, and experience with FMLA. Methods: The intervention consisted of computer-based training (CBT) and a survey measuring awareness and experience with FMLA. The training was administered to 793 county government supervisors in the state of Oregon, USA. Results: More than 35% of supervisors reported no previous training on FMLA and the training pre-test revealed a lack of knowledge regarding benefit coverage and employer responsibilities. The CBT achieved: (1) a significant learning effect and large effect size of d = 2.0, (2) a positive reaction to the training and its design, and (3) evidence of increased knowledge and awareness regarding FMLA. Conclusion: CBT is an effective strategy to increase supervisors' knowledge and awareness to support policy implementation. The lack of supervisor training and knowledge of an important but complex employee benefit exposes a serious impediment to effective policy implementation and may lead to negative outcomes for the organization and the employee, supporting the Ryan-Kossek model. The results further demonstrate that long-time employees need supplementary training on complex workplace policies such as FMLA.

A Dynamically Segmented DCT Technique for Grid Artifact Suppression in X-ray Images (X-ray 영상에서 그리드 아티팩트 개선을 위한 동적 분할 기반 DCT 기법)

  • Kim, Hyunggue;Jung, Joongeun;Lee, Jihyun;Park, Joonhyuk;Seo, Jisu;Kim, Hojoon
    • KIPS Transactions on Software and Data Engineering
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    • v.8 no.4
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    • pp.171-178
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    • 2019
  • The use of anti-scatter grids in radiographic imaging has the advantage of preventing the image distortion caused by scattered radiation. However, it carries the side effect of leaving artifacts in the X-ray image. In this paper, we propose a grid line suppression technique using discrete cosine transform(DCT). In X-ray images, the grid lines have different characteristics depending on the shape of the object and the area of the image. To solve this problem, we adopt the DCT transform based on a dynamic segmentation, and propose a filter transfer function for each individual segment. An algorithm for detecting the band of grid lines in frequency domain and a band stop filter(BSF) with a filter transfer function of a combination of Kaiser window and Butterworth filter have been proposed. To solve the blocking effects, we present a method to determine the pixel values using multiple structured images. The validity of the proposed theory has been evaluated from the experimental results using 140 X-ray images.

Effect of the incoherent earthquake motion on responses of seismically isolated nuclear power plant structure

  • Ahmed, Kaiser;Kim, Dookie;Lee, Sang H.
    • Earthquakes and Structures
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    • v.14 no.1
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    • pp.33-44
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    • 2018
  • Base-isolated nuclear power plant (BI-NPP) structures are founded on expanded basemat as a flexible floating nuclear island, are still lacking the recommendation of the consideration of incoherent motion effect. The effect of incoherent earthquake motion on the seismic response of BI-NPP structure has been investigated herein. The incoherency of the ground motions is applied by using an isotropic frequency-dependent spatial correlation function to perform the conditional simulation of the reference design spectrum compatible ground motion in time domain. Time history analysis of two structural models with 486 and 5 equivalent lead plug rubber bearing (LRB) base-isolators have been done under uniform excitation and multiple point excitation. two different cases have been considered: 1) Incoherent motion generated for soft soil and 2) Incoherent motion generated for hard rock soil. The results show that the incoherent motions reduce acceleration and the lateral displacement responses and the reduction is noticeable at soft soil site and higher frequencies.

A Study on Design and Fabricate of a Intermediate Frequency Band SAW Filter (IF 대역 SAW 필터 설계 및 제작)

  • 유일현;권희두;정양희
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.1
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    • pp.10-15
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    • 1999
  • We have studied a method to design and fabricate the Intermediate Frequency(IF) band pass filter with low shape factor which is used for CDMA base station on the 35°Y-cut X-propagation Quartz substrate. In order to fabricate a device of the low shape factor for the IF SAW filter on this substrate, we employed apodization weighted type interdigital transducer(IDT) as an input and withdrawal weighted type IDT as an output by using impulse modelling method. Also, using the Kaiser-Bessel window function, we have adopted 2200pairs and 1000pairs of input and oueut IDT respectively to minimize the effect of ripple. Furthermore, the width and the space of IDT finger are 3.6 ㎛ and 3.5 ㎛ respectively. Thus, we can have optimal results when the IDT thickness is 6000Å in consideration of the ratio of SAW's wavelength while it's aperture is 2mm for impedance matching. The fabricated SAW filter for CDMA had the property of almost 115.2MHz of a center frequency, less then 1.27MHz of bandwidth, less than 1.3 of shape factor, - l5dB of out band attenuation insertion loss and -45dB of rejection band.

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Crack Source location Technique for nam Concrete Beam using Acoustic Emission (음향방출을 이용한 무근콘크리트 보의 균열 발생원 탐사기법)

  • 한상훈;이웅종;조홍동;김동규
    • Journal of the Korea Concrete Institute
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    • v.13 no.2
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    • pp.107-113
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    • 2001
  • This study was conducted preliminarily to develop the crack source location technique for plain concrete beam using acoustic emission(AE). Before the main experiment, the test of virtual An source location was achieved in plain concrete block. The sensor layout was mutually compared between triangular layout and rectangular layout. As the results of test, AE source location by triangular layout was evaluated more effective than that by rectangular layout. The specimen to apply he source location technique was man in total nine specimens (each three in 40 %, 50%, 60% of W/C ratio) which the experiment variable was the compressive strength level(W/C ratio). The bending loading method is selected by cyclic loadings to evaluate the degree of concrete damage. It is seen that Kaiser effect and Felicity effect exists through analysis of AE parameters in coming failure experiment. As a result of analyzing the felicity ratio(FR) values, it is shown that this values can be used for evaluating the degree of concerto damage. AE activity is started highly at the 70% of failure load without the compressive strength level. Thus considered by a index in constructing the system of the failure warning at application of the field structure. And the results compared the real cracking location with the source location has perceived by AE monitoring before it is appeared the primary crack by visual observation.

Application of Acoustic Emission Technique for Crack Source Location Search in Plain Concrete (무근 콘크리트에서 균열 발생원 탐사를 위한 AE 기법의 적용)

  • 한상훈;이웅종;조홍동;김동규
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.793-798
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    • 1999
  • This study was conducted to evaluate structural integrity and crack source location of plain concrete beams using acoustic emission. Three point bending tests were carried out plain concrete specimen under cyclic loadings. The variable is W/C of concrete. From the tests it was shown that a breakdown of the kaiser effect and high AE activities during unloading could be effective indices to estimate the level of deterioration in plain concrete structures. The time and location and propagation of crack could be easily determined by monitoring AE, which concludes that AE technique can be a very useful tool to evaluate structural integrity of concrete plain beams.

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Responses of Ultrasonic Backscattered Energy and AE Charateristics on the Progressive Damage of Crossply Composite Laminates (초음파와 음향 방출법을 이용한 복합재료 직교적층판의 점진적 손상과정에 관한 연구)

  • Jeon, Heung-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.5 s.176
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    • pp.1084-1092
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    • 2000
  • Responses of ultrasonic back scattered energy and AE (Acoustic Emission) characteristics related to the progressive damage of $[0/90-{2}]_s$ and $[0/90-{4}]_s$ crossply laminates were studied. It was found that the ultrasonic backscattered energy was sensitive to the matrix cracking but not sensitive to other failure mechanisms. However, AE was proved to be sensitive to matrix cracking as well as other failure mechanisms.AE signals were analyzed by investigating the amplitude and number of counts per event for corresponding applied strain. Loading and unloading tests were conducted separately. AE results showed Kaiser effect in the crossply composite laminates and ultrasonic results supported the AE results.

A Study on the Dynamic Fracture Toughness of Welding Structural Steels by Instrumented Impact Testing (계장화 충격시험법에 의한 구조용강 용접부의 동적 파괴인성에 관한 연구)

  • 김헌주;김경민;윤의박
    • Journal of Welding and Joining
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    • v.11 no.1
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    • pp.42-51
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    • 1993
  • In this study, investigations were conducted in calculating parameters of elastic-plastic fracture mechanics using single specimen. The validity of these testing methods was judged by the confirmation of multiple specimen method of stop block test. The results were as follows: In order to measure a fracture toughness using the instrumented impact test, two general requirement must be considered; One, setting up proper impact velocity considered the effect of loading and the other, the necessity of low blow test for obtaining true energy by the compliance correction. It was possible to detect a crack initiation point by calculating the compliance changing rate from a load-defection curve. Criterion of a stable crack growth, $T_{mat}$ could be estimated by using key-curve method for a base metal. and combining Kaiser's rebound compliance with Paris-Hutchison's $T_{appl}$ equation for the brittled zone of welding heat affected.at affected.d.

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Quantitative Damage Evaluation of Fiber-Reinforced Cement Composite Using Acoustic Emission Technique (음향방출 기법을 이용한 섬유보강 시멘트 복합체의 정량적 손상평가)

  • Lee, Young-Oh;Yun, Yeo-Jin;Yun, Hyun-Do
    • Journal of the Korea Concrete Institute
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    • v.21 no.4
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    • pp.457-464
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    • 2009
  • Fiber is an important ingredient in fiber-reinforced cement composite (FRCC) which can control fracture of cement composite by bridging action. In compliance with the action of the fiber and the aggregate size, it also showed a different failure mechanism. For practical application, it is needed to investigate the fracture behavior of the FRCC and to understand the micro-mechanism of cement matrix with reinforcing fiber. In order to evaluate a characteristics of fracture process in the FRCC, acoustic emission (AE) technique was used for the analysis and evaluation of FRCC damage by acoustic emission under flexural and cyclic compressive loadings. The AE signals were monitored by AMSY4 AE instrument during the entire loading period. The specimens are reinforced with 0, 1.0, 1.5 and 2.0% (by volume) Polyvinyl alcohol (PVA) fiber. The test results showed that the damage progress of the FRCC was characteristic for the fiber replacement ratio. As a result of analyzing the felicity ratio (FR) values, it is shown that this values can be used for evaluating the degree of FRCC damage. On the whole the felicity ratio values of FRCC are shown between 0.4 and 1.1. And, the AE kaiser effect was shown in the all FRCC specimen. In addition, the damage behavior and the microscopic fracture process of the FRCC are evaluated using the AE parameters, such as calm ratio, b-value and felicity ratio. The purpose of this reserch was to advance the state of knowledge regarding the applicability of acoustic emission as an evaluation method for FRCC.

Objective Effects and Satisfaction of Mouth Gymnastics Program (입체조 프로그램의 객관적 효과와 만족도 조사)

  • Jang, Kyeung-Ae;Hwang, In-Chul
    • The Journal of the Korea Contents Association
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    • v.11 no.10
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    • pp.388-395
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    • 2011
  • This study was performed to grasp the relation between the effect and the satisfaction of a mouth gymnastics program on the promotion of oral function of old persons. The experimental group of 47 old persons conducted a mouth gymnastics exercise two times every week for 12 weeks, while the control group of 39 old persons carrying out physical examinations. The mean salivary secretion in the experimental group was 0.075 ml and more than 0.046 ml in the control group. Maximum mouth opening in the experimental group, 4.12 cm, was higher than 3.92 cm in the control. Oral diadochokinesis in experimental and control group was 1.69 times per second and 1.65, respectively. The result of principal component analysis by Quartimax method with Kaiser normalization showed that program prevalence prediction of mouth-gymnastics exercise was high, and it is estimated that this exercise program would be more popular for health promotion of old persons. From the correlation analysis, mouth gymnastics exercise made salivary flow increase(r=.592), this exercise should be recommended actively for improving mouth health of old persons. Also more modification is required for old persons with difficulty in mouth gymnastics exercise. Some movements of the mouth gymnastics exercise need be modified, and then the exercise should be publicized as one of the ways to improve holistic health of the aged.