• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.53-63
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• 2022

Despite the relationship between cash flow, financial management, and project performance, no study examined the mediating role of financial management on the relationship between cash flow and construction project performance, especially in Kuwait. The goal of this study was to examine the impact of cash flow fluctuations on construction project performance, as well as the role of financial management in mediating this relationship. To accomplish these goals, the researcher employed a descriptive-analytical method to create a questionnaire of 31 items. The study's sample was chosen at random and includes (181) project managers and firm owners from contractors' companies in Kuwait. The study found a statistically positive and significant effect of cash flow variation on project performance from the perspective of Kuwaiti contractors at the significance level (0.05), as well as a mediated role of financial management in the relationship between cash flow variation and project performance. The research came up with a number of recommendations based on the findings, including the need for contractors to have a better understanding of cash flow to arrange project activities correctly and efficiently. Further studies may be included into the effect of cash flow forecasting (planning) and financial management (control) on various construction activities.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.1
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• pp.15-20
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• 2015

In this study, the optimization and performance characteristics of a cascade heat pump system was analyzed with the variation of low stage refrigerant charge amount. The cascade heat pump was designed and constructed with R134a and R410A as the refrigerant for high stage and low stage cycle, respectively. Experiments were conducted by varying the low stage charge amount and the performance characteristics of the cascade heat pump were studied. The refrigerant charge amount of the low stage cycle was varied between the ranges of -15% and +10% of the optimum charge amount. The performance variation experienced in the cascade heat pump due to the variation of refrigerant charge amount shows greater effect in the undercharge regions than the overcharge regions. COP reduction in the undercharge region is larger than the decrease in the overcharge region. Some cycle variation such as power consumption and cycle pressure according to low stage refrigerant charge amount showed different trends comparing with those according to high stage refrrgerant charge amount. Therefore, the optimum charge amount of the cascade heat pump should be determined based on the experimental data obtained by the variation of high and low stage refrigerant charge amount.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2157-2165
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• 2006

In implementing GCRA, well known as the representative user traffic policing algorithm for constant-bit rate service, it is essential to set proper values for delay variation tolerance in order to prevent network overload and excessive user data loss due to delay variation incurred inevitably during transmission process. In this paper, we investigate the performance of GCRA algorithm for various values of delay variation tolerance and suggest a guideline for setting proper delay variation tolerance values.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.3
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• pp.241-245
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• 2001

In this paper, we present parameter optimization technique for GaAs/AlGaAs multiple quantum well avalanche photodiodes used for image capture mechanism in high-definition system. Even under flawless environment in semiconductor manufacturing process, random variation in process parameters can bring the fluctuation to device performance. The precise modeling for this variation is thus required for accurate prediction of device performance. The precise modeling for this variation is thus required for accurate prediction of device performance. This paper will first use experimental design and neural networks to model the nonlinear relationship between device process parameters and device performance parameters. The derived model was then put into genetic algorithms to acquire optimized device process parameters. From the optimized technique, we can predict device performance before high-volume manufacturign, and also increase production efficiency.

• Journal of Distribution Science
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• v.16 no.9
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• pp.53-58
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• 2018

Purpose - This study aims to examine how the time variations of customer satisfaction influence retail firms' performance. Research design, data, and methodology - The study employs yearly time series customer satisfaction data of Korean retail secured from the National Customer Satisfaction Index(NCSI) for the 2011~2016 period. Our data includes a total of 90 observations of 15 retail firms in 5 different sector(department store, filling station, large discount store, open market, TV home shopping). We obtained the firm performance data from the KIS Value database. The variables for financial performance include sales and net profit. Results - The results show that customer satisfaction has dynamic effects on retail firms' performance. More specifically, the time variation of customer satisfaction has the moderating effect on the linkage between customer satisfaction and financial performance as well as direct effects on the firms' financial performance. Conclusions - Customer satisfaction has the current effect lasting over time on firm performance and changes of customer satisfaction in positive direction also impact on firm performance. Retail firms need to not only focus on improving customer satisfaction in the current term, but make efforts to continuously enhance customer satisfaction in the long term.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.374-379
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• 2001

In this paper, a novel design algorithm of speed controller for an Induction motor with the inertia variation is proposed. The main contribution of our work is a very robust, reliable and stable procedure for setting of the PI gains against the specified range of the inertia variation of an induction motor using Kharitonovs robust control theory. Therefore, the basic segment of controller design, the variation of induction motor inertia is estimated by the RLS (Recursive least square) method. PI based speed controller is widely used in industrial application for its simple structure and reliable performance. In addition the Kharitonov robust control theory is used for verification stability of closed-loop transfer function. The performance of this proposed design method is proved by digital simulation and experimentation with high performance DSP based induction motor driving system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2194-2200
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• 1994

In an automotive spark ignition engine, it is important to form the proper mixture (air/fuel) on each driving condition for developing the stabilizing combustion and exhaust characteristics. Since most of supply fuel si attached on the inside wall of the intake manifold for unadequate nonuniformity of fuel distribution to each cylinder and mixture variation. Also it affects engine performance variation and causes noises and vibration. In this study, we verified the effect of the mixture variation which is caused by fuel liquid film in the intake manifold on combustion characteristics and engine performance.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1271-1278
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• 2010

High-speed traction has voltage source variation because the electric power of tractions is supplied by difference traction power system according to operating section. This paper proposes the robust control maintaining constant output performance against voltage source variation for PWM converters of the high speed traction. The proposed scheme consists of feed-forward compensation for current controller by on-line calculating the rms voltage of voltage source. Total dynamic performance of high speed traction can be improved by the reduction of the output voltage ripple which is resulted from voltage source sag and variation. The superior performance and validity of the proposed scheme is proved through the simulation.

• The KSFM Journal of Fluid Machinery
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• v.13 no.6
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• pp.51-56
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• 2010

A numerical simulation is carried out to investigate the effect of flow rate variation and performance characteristics of double-suction centrifugal pump. Two types of pump which have different impeller inlet breadth and curvature of the shroud line consist of six blades impeller and shroud ring. Finite-volume method with structured mesh and $k-\omega$ Shear Stress Transport turbulence model was used to guaranty more accurate prediction of turbulent flow in the pump impeller. Total head, power and overall efficiency were calculated to obtain performance characteristics of two types of pump according to the variation of flow rate. From the results, impeller having smooth curve along the shroud line obtained good performance. The lower flow rate, the more circulation region, flow unsteadiness and complicate flow pattern are observed. Complicated internal flow phenomena through impellers such as flow separation, pressure loss, flow unsteadiness and performance are investigated and discussed.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.12-14
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• 1996

In this paper, the simulation of the effects of variation of rotor resistance of induction motor for the performance of vector control is presented. Especially, this paper considered the effects as a difference variation of the rotor resistance between slip calculator and induction motor.