Does Okun’s Law and its Coefficient value, β exist? Evidence from Sixteenth South and Southeast Asian Countries during 1991-2020

Abdus Samad(Abdus Samad ) People&Global Business Association 2023 Global Business and Finance Review Vol.28 No.1

Purpose: This paper retested the Okun’s Law established in the 1960s and the subsequent research on Okun’s findings that a 1% increase in unemployment would lead to a 3 % decrease in GDP), i.e. Okun’s coefficient (β)=-3 in diverse economies of sixteen South and Southeast Asia, sixteen countries. Design/methodology/approach: Using panel data in two models, the first difference model: (Yt -Yt-1) = α - β(Ut-Ut-1) and the gap model: (Yt -Y,) = α - β(Ut -U)were estimated. Findings: Results of pool ordinary least square (POLS), Fixed Effect Model (FEM), and Random Effects Model(REM) supports Okun’s Law and shows that the coefficient, β, is (-4.4) suggesting that every 1 percent unemployment rate leads to 4.4 decrease in GDP. The Okun’s coefficient varies with country. The validity of Okun’ coefficient, β= -2 percent, is found only in four. Findings of negative coefficient and its significance provides important policy prescriptions for nine countries. Research limitations/implications: This paper suffers from limitations. First data limitation. This paper used annual data of 30 years. Future research may include quarterly data or annual data with more observations. Second, as Hodrick and Prescott [1997] filtering approach suffers from criticism, Cobb-Douglas production function estimate may be applied for estimating full-employment GDP and natural rate of unemployment. Originality/value: All studies of Okun’s law studies derived its coefficient focused on the economically developed countries, this study is an exception. The survey of literature shows that there is no research of Okun’s for sixteen South and Southeast Asian countries with diverse level of economic growth. So, the result of this study is an important contribution in the literature of Okun’s law. Second, as the policy makers of these countries are facing mounting pressure of unemployment, finding the value of Okun’s coefficient is a contribution of this paper for them.

Flow Analyses Inside Jet Pumps Used for Oil Wells

Samad, Abdus,Nizamuddin, Mohammad Korean Society for Fluid machinery 2013 International journal of fluid machinery and syste Vol.6 No.1

Jet pump is one type of artificial lifts and is used when depth and deviation of producing wells increases and pressure depletion occurs. In the present study, numerical analysis has been carried out to analyze the flow behavior and find the performance of the jet pump. Reynolds-averaged Navier Stokes equations were solved and k-${\varepsilon}$ turbulence model was used for simulations. Water and light oil as primary fluids were used to pump water, light oil and heavy oil. The ratios of area and length to diameter of the mixing tube were considered as design parameters. The pump efficiency was considered to maximize for the downhole conditions. It was found that the increase in viscosity and density of the secondary fluid reduced efficiency of the system. Water as primary fluid produced better efficiency than the light oil. It was also found that the longer throat length increased efficiency upto 40% if light oil was used as primary fluid and secondary fluid viscosity was 350 cSt.

Numerical Analysis of Centrifugal Impeller for Different Viscous Liquids

Abdus Samad,Sayed Ahmed Imran Bellary 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.1

Oil and gas industry pumps viscous fluids and investigation of flow physics is important to understand the machine behavior to deliver such fluids. 3D numerical flow simulation and analysis for different viscous fluids at different rotational speeds of a centrifugal impeller have been reported in this paper. Reynolds-averaged Navier Stokes (RANS) equations were solved and the performance analysis was made. Standard two equation k-ε model was used for the turbulence closure of steady incompressible flow. An inlet recirculation and reverse flow in impeller passage was observed at low impeller speeds. It was also found that the higher viscosity fluids have higher recirculation which hinders the impeller performance.

Shape Optimization of a Dimpled Channel to Enhance Heat Transfer Using a Weighted-Average Surrogate Model

Samad, Abdus,Lee, Ki-Don,Kim, Kwang-Yong Informa UK (TaylorFrancis) 2010 Heat transfer engineering Vol.31 No.13

Multi-Objective Shape Optimization of an Axial Fan Blade

Samad, Abdus,Lee, Ki-Sang,Kim, Kwang-Yong The Society of Air-Conditioning and Refrigerating 2008 International Journal Of Air-Conditioning and Refr Vol.16 No.1

Numerical optimization for design of a blade stacking line of a low speed axial flow fan with a fast and elitist Non-Dominated Sorting of Genetic Algorithm(NSGA-II) of multi-objective optimization using three-dimensional Navier-Stokes analysis is presented in this work. Reynolds-averaged Navier-Stokes(RANS) equations with ${\kappa}-{\varepsilon}$ turbulence model are discretized with finite volume approximations and solved on unstructured grids. Regression analysis is performed to get second order polynomial response which is used to generate Pareto optimal front with help of NSGA-II and local search strategy with weighted sum approach to refine the result obtained by NSGA-II to get better Pareto optimal front. Four geometric variables related to spanwise distributions of sweep and lean of blade stacking line are chosen as design variables to find higher performed fan blade. The performance is measured in terms of the objectives; total efficiency, total pressure and torque. Hence the motive of the optimization is to enhance total efficiency and total pressure and to reduce torque.

Application of Surrogate Modeling to Design of A Compressor Blade to Optimize Stacking and Thickness

Samad, Abdus,Kim, Kwang-Yong Korean Society for Fluid machinery 2009 International journal of fluid machinery and syste Vol.2 No.1

Surrogate modeling is applied to a compressor blade shape optimization to modify its stacking line and thickness to enhance adiabatic efficiency and total pressure ratio. Six design variables are defined by parametric curves and three objectives; efficiency, total pressure and a combined objective of efficiency and total pressure are considered to enhance the performance of compressor blade. Latin hypercube sampling of design of experiments is used to generate 55 designs within design space constituted by the lower and upper limits of variables. Optimum designs are found by formulating a PRESS (predicted error sum of squares) based averaging (PBA) surrogate model with the help of a gradient based optimization algorithm. The optimum designs using the current variables show that, to optimize the performance of turbomachinery blade, the adiabatic efficiency objective is improved substantially while total pressure ratio objective is increased a very small amount. The multi-objective optimization shows that the efficiency can be increased with the less compensation of total pressure reduction or both objectives can be increased simultaneously.

동북아시아 경제협력: 한국, 중국, 일본을 중심으로

( Samad Syed Abdus ) 순천향대학교 사회과학연구소 2009 사회과학연구 Vol.15 No.1

본 논문은 중국, 한국, 일본 그리고 러시아와의 통합경제동맹에 대한 전망의 가능성을 점검하고 있다. 이에 대한 연구를 위하여 이들 북동 아시아지역 국가들에 대한 정치와 경제에 관한 역사를 분석하고 있다. 본 논문에서는 이들 국가에 대한 법리적-사법적 틀에 대한 논의는 하지 않는다. 본 논문은 특히 경제통합동맹에 대한 문제점과 쟁점에 초점을 맞추고 이들 모든 국가들이 동조하여야만 하는 통합동맹에 대한 가능성을 권고하고 있다. The paper examines the prospects of an integrated economic union for China, Korea and Japan, with Russia as a possible fourth member. It analyses the history of political and economic development of the countries of northeast Asia with focus on the major three leading ones. There is no legal-juridical framework for such cooperation at the present time and current programs are stand alone types. The paper highlights the problems and issues of the proposed union and recommends a rigorous feasibility study for the integrated union to which all the countries must agree. Without such a study the full complementarities of the economies of the region can not be gauged properly. This should be done soon if there is indeed an intent for institutionalized cooperation on the model of EU or NAFTA

Performance of Surrogate Models in Optimizing Heat Transfer Augmentation Devices

Abdus Samad(압두스 사마드),Kwang-Yong Kim(김광용) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

A three dimensional channel with oblique rib attached on both walls has been optimized to enhance turbulent heat transfer using multiple surrogate models. Objective functions values are evaluated at design points by Reynolds-averaged Navier-Stokes analysis, and surrogates models are constructed for optimization. It is found that the turbulent heat transfer rates increased reasonably by shape optimization and the multiple surrogate methods performed well since these models protect the designer from using any individual basic surrogate poor in prediction. The present approach can help to address the multi-objective designs on a rational basis with quantifiable cost-benefit analysis of system design.

Evaluation of Surrogate Models for Shape Optimization of Compressor Blades

Abdus Samad,Kwang-Yong Kim 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Performances of multiple surrogate models are evaluated in a turbomachinery blade shape optimization. The basic models, i.e., Response Surface Approximation, Kriging and Radial Basis Neural Network models as well as weighted average models are tested for shape optimization. Global data based errors for each surrogates are used to calculate the weights. These weights are multiplied with the respective surrogates to get the final weighted average models. The design points are selected using three level fractional factorial D-optimal designs. The present approach can help address the multi-objective design on a rational basis with quantifiable cost-benefit analysis.

Effects of Surface Roughness on Turbomachinery Blade Performance

Abdus Samad(사마드압두스),Kwang-Yong Kim(김광용) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Deterioration of surface of turbomachinery blades occur in course of time and hence reduce the performance of the machine. In this paper, transonic axial compressor blade surface roughness is studied considering a reference blade and a shape distorted (optimized) blade. Optimal blade is designed considering sweep and lean. Roughened blade by changing Reynolds roughness number and hydraulically smooth blade is numerically formulated and is compared the different parameters like adiabatic efficiency, total temperature ratio, total pressure ratio and Mach number. Baldwin-Lomax turbulence model is used for flow field analysis and Cebeci-Smith roughness model is formulated for roughness modeling. It is found the performance in terms of adiabatic efficiency, total temperature ratio, total pressure ratio is decreased and Mach number is increased. Performance deterioration is more severe in case of distorted blade as compared to reference blade.