• The Journal of Asian Finance, Economics and Business
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• 제7권5호
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• pp.225-236
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• 2020

This paper examines empirically the net impact of residual state ownership on privatized firm efficiency in the transitional context of Vietnam. Vietnamese privatization has its own characteristics. Instead of mass and full privatization, Vietnam has chosen a partial and gradual path. Thus, it is important to assess the net impact of residual state ownership on privatized firms during the post-privatization period. This study employs stochastic frontier analysis to investigate the association between residual state ownership and the efficiency of privatized firms, using a sample of all privatized firms that are listed on the Vietnamese stock exchanges over the period from 2007 to 2017. Also, two-stage least squares regression is incorporated into the model to deal with potential endogeneity issues. Our study provides evidence that state ownership should not be considered as a pure source of agency problems. Indeed, the net impact of residual state ownership on privatized firm efficiency is non-monotonic, and the relationship between residual state ownership and privatized firm efficiency is under an inverted U-shape. A moderate level (less than 50%) of residual state ownership might be beneficial to privatized firm efficiency whereas too much state ownership is detrimental to the efficiency of privatized firms.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.134-143
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• 2002

Using OGCM results, we have shown that the ring-like cold baroclinic eddies associated with cyclonic circulation are shed from late summer to early fall near the Izu-Ogasawara Ridge from the Kuroshio Extension owing to baroclinic instability. On the other hand, warm baroclinic eddies are generated by the intensified western boundary current associated with the warm anomaly accumulated near the Ridge in winter, which corresponds to the basin-wide barotropic intensification of the wind-driven gyre in winter. We are successful in reproducing the behavior of those meso-scale eddies using a simple two-layer primitive equation model driven by seasonal winds associated with the positive curl. Those eddies carry barotropic seasonal signals originated in the Pacific Basin quite slowly west of the ridge; this process introduces a phase lag in the timing of the seasonal maximum transport in the Philippine Basin west of the ridge. It Is demonstrated that the existence of bottom topography, baroclinicity, and nonlinearity due to advection are three necessary elements for the generation of these eddies south of Japan.

• 한국안전학회지
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• 제20권1호
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• pp.42-48
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• 2005

The present study investigates the effect of balcony on external smoke movement of high rise building through the fire tests of the 1/10 reduced model scale using Froude scaling. A hexane pool fire is used to examine the smoke movement for various opening sizes of balcony and temperature distributions are measured by T-type thermocouples. Also, hydrogen bubble technique is applied to visualize the smoke movement near the balcony. Measured temperatures of the closed balcony is 2.5 times higher than those of the open balcony because the external smoke in case of the closed balcony rise along the vertical wall. The maximum vertical temperature of partially closed balcony is similar with fully closed balcony and mean temperature inside of balcony increases as opening size of balcony decreases. The experimental results show that the balcony space plays an important roles in preventing fire propagation and cooling of smoke layer. In order to ensure the fire safety in high rise building design, a series of systematic researches are required to examine the various type of balconies.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.1-13
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• 2020

This study examines the effect of managerial ownership on firm value in capital markets where outside governance mechanisms to discipline managers are weak or non-existent. We hypothesize that strong market forces in the U.S. confound the effect of managerial ownership on firm value, i.e., the convergence of interest argument. We test the hypothesis using data from 112 firms from Singapore Stock Exchange and 205 firms from the Stock Exchange of Thailand prior to the Asian financial crisis in 1997 when the market forces were weak, yet the investor protection was sufficient to prevent outright appropriation from management. For ease of comparison, we use methodologies from studies done on the U.S. sample firms during the same study period as ours. We find that, both in Singapore and Thailand, firm value is a function of managerial ownership, and the relation is of the famous inverted U-shaped. Moreover, the relation is robust under different model specifications. The results from Thai sample, with weaker market forces than in Singapore, lend support to many agency cost hypotheses advanced in the U.S. Our results provide useful implication for investors in emerging and frontier markets where outside governance mechanisms are yet to be fully developed.

• Structural Engineering and Mechanics
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• 제78권3호
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• pp.319-332
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• 2021

The wood-concrete composite is an interesting solution in the field of Civil Engineering to create high performance bending elements for bridges, as well as in the building construction for the design of wood concrete floor systems. The authors of this paper has been working for the past few years on the development of the bonding process as applied to wood-concrete composite structures. Contrary to conventional joining connectors, this assembling technique does ensure an almost perfect connection between wood and concrete. This paper presents a careful theoretical investigation into interfacial stresses at the level of the two interfaces in composite wooden beam- reinforced concrete slab strengthened by external bonding of prestressed composite plate under a uniformly distributed load. The model is based on equilibrium and deformations compatibility requirements in all parts of the strengthened composite beam, i.e., the wooden beam, RC slab, the CFRP plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. This research is helpful for the understanding on mechanical behaviour of the interface and design of the CFRP- wooden-concrete hybrid structures.

• Advances in nano research
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• 제10권2호
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• pp.129-138
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• 2021

In present article, utilizing the Love shell theory with volume fraction laws for the cylindrical shells vibrations provides a governing equation for the distribution of material composition of material. Isotopic materials are the constituents of these rings. The position of a ring support has been taken along the radial direction. The Rayleigh-Ritz method with three different fraction laws gives birth to the shell frequency equation. Moreover, the effect of height- and length-to-radius ratio and angular speed is investigated. The results are depicted for circumferential wave number, length- and height-radius ratios with three laws. It is found that the backward and forward frequencies of exponential fraction law are sandwich between polynomial and trigonometric laws. It is examined that the backward and forward frequencies increase and decrease on increasing the ratio of height- and length-to-radius ratio. As the position of ring is enhanced for clamped simply supported and simply supported-simply supported boundary conditions, the frequencies go up. At mid-point, all the frequencies are higher and after that the frequencies decreases. The frequencies are same at initial and final stage and rust itself a bell shape. The shell is stabilized by ring supports to increase the stiffness and strength. Comparison is made for non-rotating and rotating cylindrical shell for the efficiency of the model. The results generated by computer software MATLAB.

• Advances in concrete construction
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• 제13권4호
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• pp.327-337
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• 2022

This paper is concerned with the vibration analysis of middle layer cylindrical shell made of functionally graded material. The outer layers and inner layer are composed of functionally graded and isotropic material respectively. The Rayleigh Ritz method is applied to solve the presented shell dynamics equations. Two configurations are constructed with layers distributions. Fundamental natural frequencies of the three layered cylindrical shell is plotted against the circumferential wave number with different power law exponents. The frequency decreases with the increase of power law exponent. The fundamental natural frequencies first decreases and fall down to its minimum value, after frequencies increases with circumferential wave number. This is due to change in the magnitude of extensional and bending energies of the cylindrical shells. The computer software MATLAB has been employed for the computation of presented frequencies and tested the results obtained in order to assess the accuracy and validity of the cylindrical shell model for predicting the vibration frequencies of cylindrical shell.

• Advances in nano research
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• 제12권5호
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• pp.489-499
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• 2022

Nanofluids have recently triggered a substantial scientific interest as cooling media. However, their stability is challenging for successful engagement in industrial applications. Different factors, including temperature, nanoparticles and base fluids characteristics, pH, ultrasonic power and frequency, agitation time, and surfactant type and concentration, determine the nanofluid stability regime. Indeed, it is often too complicated and even impossible to accurately find the conditions resulting in a stabilized nanofluid. Furthermore, there are no empirical, semi-empirical, and even intelligent scenarios for anticipating the stability of nanofluids. Therefore, this study introduces a straightforward and reliable intelligent classifier for discriminating among the stability regimes of alumina-water nanofluids based on the Zeta potential margins. In this regard, various intelligent classifiers (i.e., deep learning and multilayer perceptron neural network, decision tree, GoogleNet, and multi-output least squares support vector regression) have been designed, and their classification accuracy was compared. This comparison approved that the multilayer perceptron neural network (MLPNN) with the SoftMax activation function trained by the Bayesian regularization algorithm is the best classifier for the considered task. This intelligent classifier accurately detects the stability regimes of more than 90% of 345 different nanofluid samples. The overall classification accuracy and misclassification percent of 90.1% and 9.9% have been achieved by this model. This research is the first try toward anticipting the stability of water-alumin nanofluids from some easily measured independent variables.

• 한국인터넷방송통신학회논문지
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• 제22권1호
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• pp.103-110
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• 2022

본 논문은 단일 종목에 투자금을 전액 투자하는 것에 비해 다수의 종목에 분산투자하는 것이 투자 위험을 보다 감소시킬 수 있다는 포트폴리오 최적화 문제를 다룬다. 널리 알려진 Markowitz의 수익률에 대한 평균-분산 기법(MV)은 위험요인인 분산(또는 표준편차)을 감소시키기 위해 지배원리를 적용하여 효율적 투자선에 있는 종목들을 대상으로 분산투자하는 포트폴리오를 구성하였다. 반면에, 본 논문에서는 최소표준편차를 가진 종목을 필수 투자종목으로 선정하고, 필수 투자종목과 비양(음의, 무)의 상관관계를 갖는 종목들을 대상으로 포트폴리오를 형성하였다. 제안된 방법을 실험한 결과 MV에 비해 보다 적은 위험(표준편차)을 보였다.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.813-822
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• 2022

In this article, the buckling and free vibration of multi-directional FGM sandwich plates are investigated. The material properties of FGM sandwich plates are assumed to be varying continuously in the in the longitudinal, transverse and thickness directions. The material properties are evaluated based on Voigt's micro-mechanical model considering power law distribution method with arbitrary power index. Equations of motion for the buckling and vibration analysis of multi-directional FGM sandwich plate are obtained based on refined shear deformation theory. Analytical solution for simply supported multidirectional FGM sandwich plate is carried out using Navier's solution technique. The FGM sandwich plate considered in this work has a homogeneous ceramic core and two functionally graded face sheets. Influence of volume fraction index in the longitudinal, transverse and thickness direction, layer thickness, and geometrical parameter over natural frequency and critical buckling load of multi-directional FGM sandwich plate is investigated. The finding shows a multi-directional functionally graded structures perform better compared to uni-directional gradation. Hence, critical grading parameters have been identified which will guide researchers in selecting fabrication routes for improving the performance of such structures.