• Geomechanics and Engineering
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• v.11 no.2
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• pp.211-234
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• 2016

A total of 99 full-scale field load tests at 22 sites were compiled for this study to elucidate several issues related to the load-displacement behaviour of belled piers under axial uplift loading, including (1) interpretation criteria to define various elastic, inelastic, and "failure" states for each load test from the load-displacement curve; (2) generalized correlations among these states and determinations to the predicted ultimate uplift resistances; (3) uncertainty in the resistance model factor statistics required for reliability-based ultimate limit state (ULS) design; (4) uncertainty associated with the normalized load-displacement curves and the resulting model factor statistics required for reliability-based serviceability limit state (SLS) design; and (5) variations of the combined ULS and SLS model factor statistics for reliability-based limit state designs. The approaches discussed in this study are practical and grounded realistically on the load tests of belled piers with minimal assumptions. The results on the characterization and uncertainty of uplift load-displacement behaviour of belled piers could be served as to extend the early contributions for reliability-based ULS and SLS designs.

• Journal of Magnetics
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• v.16 no.2
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• pp.192-195
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• 2011

The phase transition of vortex matter from solid to liquid was studied in iron-based superconductors. Based on the traditional vortex glass theory, we have examined the magnetoresistivity data of iron-based superconductors using our extended thermal activation model: $\rho(B,T)=\rho((T-T_g(B))/(T_c(0)-T_g(B)))^{v(z-1)}$. We predict that the magnetic field-dependent area S + $S_0$ which integrates $\rho$ with T is proportional to $B^{\beta}$, where ${\beta}$ is the vortex glass transition exponent. From our calculation, the vortex glass transition exponent is 0.33, close to the exponent of area $S_0$ + S is 0.31 in $SmO_{0.9}F_{0.1}FeAs$; the exponent of area S is 0.63, which is close to the irreversibility line exponent 2/3. Both of the results show the validity of our model. In addition, our model is shown to be effective in describing irreversibility behavior in layered superconductors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6116-6132
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• 2017

The proxy re-encryption allows an intermediate proxy to convert a ciphertext for Alice into a ciphertext for Bob without seeing the original message and leaking out relevant information. Unlike many prior identity based proxy re-encryption schemes which are based on the number theoretic assumptions such as large integer factorization and discrete logarithm problem. In this paper, we first propose a novel identity based proxy re-encryption scheme which is based on the hardness of standard Learning With Error(LWE) problem and is CPA secure in the standard model. This scheme can be reduced to the worst-case lattice hard problem that is able to resist attacks from quantum algorithm. The key step in our construction is that the challenger how to answer the private query under a known trapdoor matrix. Our scheme enjoys properties of the non-interactivity, unidirectionality, anonymous and so on. In this paper, we utilize primitives include G-trapdoor for lattice and sample algorithms to realize simple and efficient re-encryption.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.247-249
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• 2008

There are many types of grid-connected inverter controllers; Synchronous Reference Frame (SRF)-based controller is the most popular methods. SRF-based controller is capable for reducing both of zero-steady state error and phase delay. However, SRF-based controller has a complex algorithm to apply in real application such as digital processor. Resonant controller is also reduced zero-steady state error, but its transfer function has a high order. In this paper, a simple proportional control is applied for grid connected inverter with LCL filter. LCL filter is a third order system. Applying a simple proportional controller is not increased the order of closed loop transfer function. By this technique, the single phase model is easily obtained. To reduce steady state error, proportional gain is set as high as possible, but it may produce instability. To compromise between a minimum steady state error and stability, the single phase model is evaluate through Root Locus and Bode diagram. PSIM simulation is used to verify the analysis.

• Journal of the Korean Society of Safety
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• v.9 no.4
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• pp.125-131
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• 1994

This paper proposes a dynamic recursive model with the effect analysis of machine state considering human factor(human skillfulness) In a single lot man-machine production system. This model obtained using Kalman Filtering Algorithm Is based on input state, output state, machine state. For sensitivity analysis, this model constructed is examined according to the impact of human skillfulness with computer simulation. The model studied in this paper has a great advance from the point of view a combination of three factors( human engineering, dynamic control theory, quality control ) and can also be extended in several applications.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.290-302
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• 2000

In this paper, we study on the identification of discrete-time state-space model for robust control of tandem cold mill, using a MOESP(MIMO output-error state-space model identification) algorithm based on subspace method. It is shown that the identified model is well adapted to input-output data sets, which are obtained from nonlinear mathematical equations of tandem cold mill. Furthermore, deterministic H$\infty$ norm bounds on uncertainties including modeling errors and disturbances are quantitatively identified in the frequency domain. Finally, the results give a basic idea to determine weighting functions included in formulating some robust control problems of tandem cold mill.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1219-1225
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• 2017

In this work, a scalable algorithm for model calibration in nuclear engineering applications is presented and tested. The algorithm relies on the construction of surrogate models to replace the original model within the region of interest. These surrogate models can be constructed efficiently via reduced order modeling and subspace analysis. Once constructed, these surrogate models can be used to perform computationally expensive mathematical analyses. This work proposes a surrogate based model calibration algorithm. The proposed algorithm is used to calibrate various neutronics and thermal-hydraulics parameters. The virtual environment for reactor applications-core simulator (VERA-CS) is used to simulate a three-dimensional core depletion problem. The proposed algorithm is then used to construct a reduced order model (a surrogate) which is then used in a Bayesian approach to calibrate the neutronics and thermal-hydraulics parameters. The algorithm is tested and the benefits of data assimilation and calibration are highlighted in an uncertainty quantification study and requantification after the calibration process. Results showed that the proposed algorithm could help to reduce the uncertainty in key reactor attributes based on experimental and operational data.

• Journal of Distribution Science
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• v.22 no.3
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• pp.59-70
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• 2024

Purpose: This study aimed to develop a strategic business conceptual model for large state plantations in West Java Province and Banten Province, Indonesia. The model was built through causal relationships and interrelationships between marketing strategies and business strategies that affect business performance on large state plantations. The plantation sector provides the largest contribution to gross domestic product and is an important part of national food distribution efforts. Research design, data, and methodology: This study used a literature review adapted from Pret and Logan (2019), which followed the guidelines of Tranfield et al. (2003), derived from the Scopus website with Q1/Q2 quartiles and inclusion/exclusion criteria published from 2012 to 2021. Results: Based on a systematic literature review approach, we constructed the strategic business conceptual model for large state plantations based on a combination of four causal and interrelationship variables that affect business performance, namely, industry attractiveness, unique capabilities, innovation management, and collaboration strategy. Conclusions: This research explains the relationship between industry attractiveness variables and unique capability as independent variables that can affect business performance through collaboration strategy and innovation management as intervening variables in the plantation sector, especially large state plantations, which have not been found in previous studies.

• Journal of Korean Academy of Nursing
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• v.34 no.3
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• pp.515-524
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• 2004

Purpose: The purpose of this study was to develop and test a model to explain the transition state for Korean middle-aged women focusing on the transition concept. Method: A hypothetical model was constructed based on the transition model of Schumacher & Meleis(1994) and tested. Thehypothetical model consisted of 5 latent variables and 11 observed variables. Exogenous variables were demographic characteristics, obstetric characteristics, and health behavior. Endogenous variables were transition state and quality of life with 6 paths. The data from 221 middle-aged women selected by convenience was analyzed using covariance structure analysis. Result: The final model which was modified from the hypotheticalmodel improved to GFI=0.97, AGFI=0.94, NFI=0.94, and NNFI=0.95. The transition state was influenced directly by demographic characteristics, quality of life, and also indirectly by health behaviors. However, the influence of obstetric characteristics was not significant. The transition state was accountable for 68% of the variance by these factors. Conclusion: These results suggest that enhancing health behaviors of the women are necessary to increase quality of life and it consequently contributes toimproving the transition state. This model could be used to explain the health related vulnerability in these ages and to diagnosis individual women.

• New & Renewable Energy
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• v.4 no.4
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• pp.65-71
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• 2008

Considering the world's environmental problem, HEVs are projected as one of the solution. The keys of the HEV cruise control are expanding the use of electric motor and operating the internal combustion engine in the efficient region. This paper presents a new structure of SOC sustaining model where state-machine control is used. The proposed model defines battery charging and discharging as states and SOC of the battery as control variables. In this paper, we introduce various methods in deterministic rule-based control for HEV and describe a new SOC sustaining controller used by state-machine.