• Title/Summary/Keyword: cyclical test

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Behavioral Patterns of Quits and Layoffs

  • Yun, Jungyoll
    • Journal of Labour Economics
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    • v.22 no.2
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    • pp.243-262
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    • 1999
  • This paper demonstrates both theoretically and empirically that there are industry-specific factors as well as the cyclical ones that affect quit and layoff incidences and that the industry-specific effects are positively correlated between the two incidences across industries while the cyclical effects are negatively correlated over time. We first set up a theoretical model to analyze how its parameters affect quits and layoffs through the corresponding change in the optimal wage for the employer and the worker, and then derive from the theoretical separation behaviors the two testable hypotheses - that quits and layoffs are positively correlated to each other across industries, and that quits move procyclically while layoffs move countercyclically. We analyze the two sets of data, BLS establishment data on turnover rates and PSID, to empirically test and confirm each of the two hypotheses.

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Behavior of FRP bonded to steel under freeze thaw cycles

  • Toufigh, Vahab;Toufigh, Vahid;Saadatmanesh, Hamid
    • Steel and Composite Structures
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    • v.14 no.1
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    • pp.41-55
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    • 2013
  • Fiber reinforced polymers (FRP) materials are increasingly being used for strengthening and repair of steel structures. An issue that concerns engineers in steel members which are retrofitted with FRP is stress experienced due to temperature changes. The changing temperature affects the interface bond between the FRP and Steel. This research focused on the effects of cyclical thermal loadings on the interface properties of FRP bounded to steel members. Over fifty tests were conducted to investigate the thermal effects on bonding between FRP and steel, which were cycled from temperature of $-11^{\circ}C$ ($12^{\circ}F$) to $60^{\circ}C$ ($140^{\circ}F$) for 21-36 days. This investigation consisted of two test protocols, 1) the tensile test of epoxy resin, tack coat, FRP and FRP-steel plate, 2) tensile test of each FRP compound and FRP with steel after going through thermal cyclic loading. This investigation reveals an extensive reduction in the composite's strength.

Characteristics Analysis of Single Phase Induction Motor via Equivalent Circuit Method and Considering Saturation Factor

  • Cho, Su-Yeon;Kim, Won-Ho;Jin, Chang-Sung;Kang, Dong-Woo;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.178-183
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    • 2014
  • This paper presents a motor characteristics analysis method using an equivalent circuit. Motor characteristics analysis via equivalent circuit is very important for designing a high efficiency single phase induction motor. The accuracy of the motor characteristics depends on the accuracy of the parameters, especially saturation factor, which determines the cyclical relationship in the analysis process. Therefore, using the proposed method, the saturation factor was calculated using the iteration routine and numerical technique. The proposed method was verified by comparing the finite element method results and the dynamo test results of manufactured prototype model.

Fatigue life curves of alloy 617 in the temperature range of 800-950℃

  • Injin Sah;Jaehwan Park;Eung-Seon Kim
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.546-554
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    • 2023
  • The cyclical behavior of Alloy 617 was examined at 25 ℃ and high temperatures of 800, 850, 900, and 950 ℃ in air to obtain its fatigue life curves. The specimens tested at 25, 800, and 850 ℃ cyclically hardened, whereas those tested above 900 ℃ cyclically softened from the first cycle, that is, their fatigue life was reduced at high temperatures owing to loss of strength. Parameters of the typical Coffin-Manson-Basquin relationship were determined for each test temperature. Interestingly, no significant difference in fatigue life was observed for the specimens tested in the range of 800-950 ℃. Owing to the similarity in fatigue life, we determined fatigue strength and fatigue ductility exponents that could be applied for this temperature range. The parameters obtained were close to the universal slopes, although the fatigue ductility exponent was slightly different. The proposed fatigue life curves were compared with those presented in ASME code.

Genetic and Environmental Trends for Milk Production Traits in Sheep Estimated with Test-day Model

  • Oravcova, Marta;Pesovicva, Dana
    • Asian-Australasian Journal of Animal Sciences
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    • v.21 no.8
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    • pp.1088-1096
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    • 2008
  • Data from milk performance testing were used to analyze genetic and environmental trends for purebred Tsigai, Improved Valachian and Lacaune sheep. 103,715 (Tsigai), 212,962 (Improved Valachian) and 2,196 (Lacaune) test-day records gathered by the State Breeding Institute of the Slovak Republic entered the analyses. The respective pedigree data comprised 23,724 (Tsigai), 51,401 (Improved Valachian) and 438 (Lacaune) records. The multiple-trait, mixed model methodology was used to predict the breeding values for daily milk yield, fat and protein content and to estimate the fixed and remaining random effects assumed to affect the above mentioned traits, separately for each breed. The breeding values for daily milk yield were adjusted for 150-day standardized lactation length by multiplying with the constant 150, as the breeding goal of the selection scheme in Slovakian sheep is to increase 150-day milk production and constant heritability throughout the whole lactation is assumed. The genetic trends were expressed as changes in averages of breeding values across birth years of animals. For Tsigai and Lacaune breeds, cumulative genetic changes over the analyzed period were 3.8 and 5.1 kg for 150-day milk, 0 and -0.16% for fat content and 0 and -0.12% for protein content. For Improved Valachian breed, either a low (1.6 kg for 150-day milk yield) or zero (fat and protein content) cumulative genetic change was found. The environmental trends were calculated as averages of solutions for flock-test day effect across years and months in which measurements were taken. A distinctive cyclical pattern which reflected short-time variation in milk production traits was found. Possible explanations for this phenomenon are given and discussed.

Gait Training Strategy by CPG in PNF with Brain Injured Patients (고유수용성 신경촉진법에서 CPG를 이용한 뇌손상자 보행훈련전략)

  • Bae Sung-soo
    • The Journal of Korean Physical Therapy
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    • v.17 no.1
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    • pp.108-122
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    • 2005
  • The gait training strategy in very important things for central nervous system(CNS) injury patients. There are many method and strategy for regaining of the gait who had CNS injury. A human being has central pattern generator(CPG) is spinal CPG for locomotion. It is a neural network which make the cyclical patterns and rhythmical activities for walking. Sensory input from loading and hip position is essential for CPG stimulation that makes the central neural rhythm and pattern generating structure. From sensory input, the proprioceptive information facilitate proximal muscles that controlled in voluntarily from cortical level and visual and / or acoustical information facilitate distal muscles that controlled voluntarily from subcortical level. Gait training method can classify that is functional level and structural level. Functional level includ level surface gait, going up and down the stair. It is important to facilitate a guide tempo in order to activate the central pattern generators. During the functional test or functional activities, can point out the poor period in gait that have to be facilitate in structural level. There are many access methods with patient position and potentiality. The methods are using of rhythmic initiation, replication and combination of isotonic with standing position. Clinically using it on weight transfer onto the stance leg, loading response, loading response and pre-swing, terminal stance, up and downwards stairs.

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Comparison and prediction of seismic performance for shear walls composed with fiber reinforced concrete

  • Zhang, Hongmei;Chen, Zhiyuan
    • Advances in concrete construction
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    • v.11 no.2
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    • pp.111-126
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    • 2021
  • Concrete cracking due to brittle tension strength significantly prevents fully utilization of the materials for "flexural-shear failure" type shear walls. Theoretical and experimental studies applying fiber reinforced concrete (FRC) have achieved fruitful results in improving the seismic performance of "flexural-shear failure" reinforced concrete shear walls. To come to an understanding of an optimal design strategy and find common performance prediction method for design methodology in terms to FRC shear walls, seismic performance on shear walls with PVA and steel FRC at edge columns and plastic region are compared in this study. The seismic behavior including damage mode, lateral bearing capacity, deformation capacity, and energy dissipation capacity are analyzed on different fiber reinforcing strategies. The experimental comparison realized that the lateral strength and deformation capacity are significantly improved for the shear walls with PVA and steel FRC in the plastic region and PVA FRC in the edge columns; PVA FRC improves both in tensile crack prevention and shear tolerance while steel FRC shows enhancement mainly in shear resistance. Moreover, the tensile strength of the FRC are suggested to be considered, and the steel bars in the tension edge reaches the ultimate strength for the confinement of the FRC in the yield and maximum lateral bearing capacity prediction comparing with the model specified in provisions.

A Study on the Impact of Business Cycle on Corporate Credit Spreads (글로벌 회사채 스프레드에 대한 경기요인 영향력 분석: 기업 신용스프레드에 대한 경기사이클의 설명력 추정을 중심으로)

  • Jae-Yong Choi
    • Asia-Pacific Journal of Business
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    • v.14 no.3
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    • pp.221-240
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    • 2023
  • Purpose - This paper investigates how business cycle impacts on corporate credit spreads since global financial crisis. Furthermore, it tests how the impact changes by the phase of the cycle. Design/methodology/approach - This study collected dataset from Barclays Global Aggregate Bond Index through the Bloomberg. It conducted multi-regression analysis by projecting business cycle using Hodrick-Prescott filtering and various cyclical variables, while ran dynamic analysis of 5-variable Vector Error Correction Model to confirm the robustness of the test. Findings - First, it proves to be statistically significant that corporate credit spreads have moved countercyclicaly since the crisis. Second, It indicates that the corporate credit spread's countercyclicality to the macroeconomic changes works symmetrically by the phase of the cycle. Third, the VECM supports that business cycle's impact on the spreads maintains more sustainably than other explanatory variable does in the model. Research implications or Originality - It becomes more appealing to accurately measure the real economic impact on corporate credit spreads as the interaction between credit and business cycle deepens. The economic impact on the spreads works symmetrically by boom and bust, which implies that the market stress could impact as another negative driver during the bust. Finally, the business cycle's sustainable impact on the spreads supports the fact that the economic recovery is the key driver for the resilience of credit cycle.

Procyclicality of Buffer Capital and Its Implications for Basel II: A Cross Country Analysis (은행 자기자본의 경기순응성에 대한 국제비교분석과 Basel II에 대한 시사점)

  • Kim, Hyeon-Wook;Lee, Hangyong
    • KDI Journal of Economic Policy
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    • v.29 no.1
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    • pp.177-196
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    • 2007
  • This paper investigates the cyclical patterns of buffer capital using an unbalanced panel data for the banks in 30 OECD countries and 7 non-OECD Asian countries. We test whether the relationships between buffer capital and business cycle are systematically different across country groups controlling for other potential determinants of bank capital. We find that the correlation is positive for developed countries while it is negative for Asian developing countries. These findings suggest that, once Basel II is implemented, developing countries are more likely to observe an increase in output volatility. We then review the policy recommendations to mitigate the procyclicality problem of Basel II.

An Impact Analysis on the Regeneration of Idle Space Affecting the Quality of Resident's Life and Local Economy Revitalization from Urban Regeneration Perspective (유휴공간의 재생이 주민 삶의 질 및 지역경제 활성화에 미치는 영향구조 분석)

  • Choi, Jin-Wook;Lee, Joo-Hyung
    • The Journal of the Korea Contents Association
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    • v.16 no.2
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    • pp.129-142
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    • 2016
  • This study evaluates the sectoral effects of the regeneration of the idle space and aims to analyze the impact relationship and structure with the quality of residents's life and local economy revitalization. this study verifies the 8 hypotheses from total 11 ones through the PLS structural equation model and suitability test for setting the hypothesis and statistical significance test. The results can be summarized into 3 parts. First, If physical, social and cultural aspects should be considered, Regeneration of idle space could meet the 2 pasts such as quality of residents life and local economy revitalization at the same time. Secondly, the regeneration of idle space from environmental aspect should be led by the local government and let it's effect leaded to local economy revitalization through the collaboration of private and public sector. Finally, it should promote the quality of resident's life and let the satisfaction linked to cyclical effects with local economy revitalization. This study has an significance that it provides the theoretical basis for regeneration of idle space and it is an empirical study for impact structure model.