• International Journal of Reliability and Applications
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• v.18 no.2
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• pp.45-63
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• 2017

In this paper, we have formulated optimum Accelerated Life Test (ALT) plan for a parallel system with two independent components using masked data with ramp-stress loading scheme and Type-I censoring. Consider a system of two independent and non-identical components connected in parallel. Such a system fails whenever all of its components has failed. The exact component that causes the system to fail is often unknown due to cost and time constraint. For each parallel system at test, we observe its system's failure time and a set of component that includes the component actually causing the system to fail. The stress-life relationship is modelled using inverse power law, and cumulative exposure model is assumed to model the effect of changing stress. The optimal plan consists in finding out the optimum stress rate using D-optimality criterion. The method developed has been explained using a numerical example and sensitivity analysis carried out.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.74-77
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• 2004

Porous membranes were prepared via thermally induced phase separation (TIPS) of (ethylene-co-vinyl alcohol) (EVOH)/glycerol mixtures. The liquid-liquid (L-L) phase boundaries are shifted to higher temperature when the ethylene contents in EVOH increase. Moreover, the kinetic study proved that the growth of droplets formed by the general liquid-liquid (L-L) phase separation obeyed a power-law scaling relationship in the later stage of spinodal decomposition (SD). A new phase separation mechanism was presented, in which the L-L phase separation could be resulted from the crystallization. The hollow fiber membranes were prepared. The membranes showed asymmetric structures with skin layer near the outer surface, the larger pores just below the skin layer and the smaller pores near the inner surface. The effect of ethylene content (EC) in EVOH, cooling water bath temperature and take-up speed on membrane performance was investigated.

• Korean System Dynamics Review
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• v.17 no.3
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• pp.31-50
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• 2016

This study examines the basic conditions of joint authorship research activities in the Korean System Dynamics Review and points out the structural co-author network characteristics among co-authored papers based on the social network analysis(SNA) techniques. In specific, this study identifies the cooperative relationship of research papers in the Korean System Dynamics Review, knowledge formation, and knowledge propagation paths. The study results imply that Korean System Dynamics Review has exhibited the typical 'Steven's power law,' which is repeatedly observed among complex systems, and that knowledge structure centered upon and propagated around couples of researchers. Additionally, the study results present that there have been active personal exchanges among major researchers. In contrast, personal contacts among research groups and within groups seem relatively weak.

• Structural Engineering and Mechanics
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• v.59 no.5
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• pp.885-899
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• 2016

The energy-based approach to predict the fatigue crack growth behavior under constant and variable amplitude loading (VAL) of the aluminum alloy 2024 T351 has been investigated and detailed analyses discussed. Firstly, the plastic strain energy was determined per cycle for different block load tests. The relationship between the crack advance and hysteretic energy dissipated per block can be represented by a power law. Then, an analytical model to estimate the lifetime for each spectrum is proposed. The results obtained are compared with the experimentally measured results and the models proposed by Klingbeil's model and Tracey's model. The evolution of the hysteretic energy dissipated per block is shown similar with that observed under constant amplitude loading.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.5
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• pp.60-68
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• 2010

The calculation method of induction voltage is abbreviately by the Ohm's law including Carson-Pollaczek's equation for mutual inductance estimation and various shielding effect coefficients. This method is mainly scoped to 60㎐. power source and the inducing/induced object positioned on the air, and the dimension of shielding material is not thoroughly reflected. In this paper, more general method of calculation is scrutinized through electromagnetic wave propagation principles. Electromagnetic force as a voltage in the spot generating from the source is evaluated according to the position of the source and object, especially their relationship with earth surface as boundary line and independent to source propagation frequency. And this method intends to consider the material specification of each object in the induction field.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.175-181
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• 2015

In this study, a lithium polymer battery (LiPB) is simply expressed by a primary RC equivalent model. The PI state observer is designed in Matlab/Simulink. The non-linear relationship with the OCV-SOC is represented to be linearized with 0.1 pu intervals by using battery parameters obtained by constant-current pulse discharge. A state equation is configured based on battery parameters. The state equation, which applied Peukert's law, can estimate SOC more accurately. SOC estimation capability was analyzed by utilizing reduced Federal Test Procedure (FTP-72) current profile and using a bi-directional DC-DC converter at temperature ($25^{\circ}C$). The PI state observer, which is designed in this study, indicated a SOC estimation error rate of ${\pm}2%$ in any of the initial SOC states. The PI state observer confirms a strong SOC estimation performance despite disturbances, such as modeling errors and noise.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.46-51
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• 2004

The cause for the variation of the initial permeability according to the Co substitution of Ni-Zn ferrite used in the LC resonance filter for the power line communication is studied. The initial permeability decreases as the quantity of Co diminishes, and the saturation magnetization increases as the quantity increases. Because the sintering density and the microstructure of ferrite show little change, the variation of the initial permeability can't be explained by the density, microstructure nor the saturation magnetization factor. The magnetocrystalline anisotropy increases, similar with the saturation magnetization, as the quantity of Co increases. The increase of magnetocrystalline anisotropy value makes the domain wall energy grow, which leads to the decrease of the initial permeability, because there's linear law between the magnetocrystalline anisotropy and the domain wall energy. The resonance frequency to Co substitution moved to high frequency band, due to the close relationship with domain wall energy, Initial permeability decreaed a little with an increase of Co contents, but resonace frequency moved to high frequency band. as a result of that, when Co was added 0.05 mol, initial permeability and resonace frequency was 75 and 25 MHz respectively.

• Journal of Korean Philosophical Society
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• v.146
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• pp.25-48
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• 2018

Starting from common sense that happiness is a state where needs are satisfied, this paper suggests the intelligence and the virtues for democratic citizens. The fact that human beings exist, relate to each other, and undertake activities which can become of moral worth when joined by autonomy, equality, and responsibility, respectively, is explained. It is also discussed that happy citizens should be able to exist autonomously in the face of political power, make an equal relationship with political power and fellow citizens, and undertake responsible activities. Lastly, it is suggested that happy citizens should be able to understand the plurality of value-contents, the similarity of value-forms, and the possibility of value-realization, and then be equipped with self-respect, mutual respect, and law-respect.

• Particle and aerosol research
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• v.12 no.1
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• pp.21-26
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• 2016

In order to realize In-line and convenient measurement for solid-gas two phase flows, Light Transmission Fluctuation (LTF) based on the random variation of transmitted light intensity, light scattering theory and cross-correlation method was presented for online measurement of particle size, concentration and velocity. The statistical relationship among transmitted light intensity, particle size and particle number in measurement zone was described by Beer-Lambert Law. Accordingly, the particle size and concentration were determined from the fluctuation signal of transmitted light intensity. Simultaneously, the particle velocity was calculated by cross-correlation analysis of two neighboring light beams. By considering the influence of concentration variation in industrial applications, the improved algorithm based on spectral analysis of transmitted light intensity was proposed to improve measurement accuracy and stability. Therefore, the online measurement system based on LTF was developed and applied to measure pulverized coal in power station and raw material in cement plant. The particle size, concentration and velocity of powder were monitored in real-time. It can provide important references for optimal control, energy saving and emission reduction of energy-intensive industries.

• Journal of Arbitration Studies
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• v.27 no.1
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• pp.85-106
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• 2017

This article deals with the relationship between arbitration and state court in each procedural stage. As most legal systems over the world respect arbitration agreement, the relationship between arbitration and state courts puts emphasis on party autonomy and provides the independent power of arbitration agreement tribunal (Kompetenz-Kompetenz). Most institutional arbitration rules the arbitral tribunal to rule on its own jurisdiction. Modern national laws have similar provisions based on Art. 16 UNCITRAL Model Law. In this regards the author throws a question in Chapter II, whether the doctrine of Kompetenz-Kompetenz, namely the ability of the tribunal to decide upon its own jurisdiction is worth while persisting, and whether the Kompetenz-Kompetenz-agreement should be regarded as valid, with the conclusion, that this doctrine should concede to the power of state court and that Kompetenz-Kompetenz-Klausel is invalid. In Chapter III the author discusses the issue of whether the breach of an arbitration agreement could lead to the compensation of damage. Although the author stands for the procedural character of arbitration agreement, he offers a proposal that the breach of an arbitration agreement bring about the compensation of damage. The issue of anti-suit injunction is discussed also in this Chapter. He is against the approval of anti-suit injunction based on an arbitration agreement resisting the other party from pursuing a lawsuit in a foreign country.