• The Journal of Asian Finance, Economics and Business
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• v.7 no.3
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• pp.157-165
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• 2020

This paper estimates the optimum level of reserves in Vietnam based on the approach of reserves' cost-benefit and sovereign risk which is one of developing countries' characteristics. The cost of reserves is the opportunity cost when holding reserves. The benefit of reserves is the loss due to country's default in case that there is no reserves to finance external debt payment. The optimum reserves is found out by minimizing the total of opportunity cost and loss due to country's default with the probability of default. Through the usage of HP Filter method for calculating the loss due to country's default, ARDL regression for the risk premium model and lending rate of VND as proxy for opportunity cost together with the Vietnamese economic data in the period of 2005 - 2017, the empirical results show that the optimum reserves in Vietnam is almost higher than the actual reserves during the research period except the point of Q3/2008 and the last point of research period - Q4/2017. Therefore, Vietnam should continue to increase reserves for safety but Vietnam does not need pushing quickly the speed of increasing reserves. In addition, controlling Vietnamese optimum reserves is necessary to help the actual reserves become reasonable.

• Journal of Information Processing Systems
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• v.7 no.3
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• pp.473-518
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• 2011

Software measurement is a key factor in managing, controlling, and improving the software development processes. Software quality is one of the most important factors for assessing the global competitive position of any software company. Thus the quantification of quality parameters and integrating them into quality models is very essential. Software quality criteria are not very easily measured and quantified. Many attempts have been made to exactly quantify the software quality parameters using various models such as ISO/IEC 9126 Quality Model, Boehm's Model, McCall's model, etc. In this paper an attempt has been made to provide a tool for precisely quantifying software quality factors with the help of quality factors stated in ISO/IEC 9126 model. Due to the unpredictable nature of the software quality attributes, the fuzzy multi criteria approach has been used to evolve the quality of the software.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.544-557
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• 2010

This paper addresses the problem of controlling the envelope's power peak of single carrier modulated signals, band limited by root-raised cosine (RRC) pulse shaping filters, in order to reduce power amplifier back-off for very small aperture terminals ground stations. Magnitude modulation (MM) is presented as a very efficient solution to the peak-to-average power ratio problem. This paper gives a detailed description of the MM concept and its recent evolutions. It starts by extending the look-up-table (LUT) based approach of the MM concept to M-ary constellations with M ${\leq}$ 16. The constellation and RRC symmetries are explored, allowing considerable reduction on LUT computation complexity and storage requirements. An effective multistage polyphase (MPMM) approach for the MM concept is then proposed. As opposed to traditional LUT-MM solutions, MM coefficients are computed in real-time by a low complexity multirate filter system. The back-off from high-power amplifier saturation is almost eliminated (reduction is greater than 95%) with just a 2-stage MPMM system even for very demanding roll-off cases (e.g., ${\alpha}$ = 0,1). Also, the MPMM is independent of modulation in use, allowing its easy application to constellations with M > 16.

• Journal of Korea Multimedia Society
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• v.18 no.2
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• pp.189-198
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• 2015

Despite the fact that traffic engineering techniques have been comprehensively utilized in the past to enhance the performance of communication networks, the distinctive characteristics of Software Defined Networking (SDN) demand new traffic engineering techniques for better traffic control and management. Considering the behavior of traffic, large flows normally carry out transfers of large blocks of data and are naturally packet latency insensitive. However, small flows are often latency-sensitive. Without intelligent traffic engineering, these small flows may be blocked in the same queue behind megabytes of file transfer traffic. So it is very important to identify large flows for different applications. In the scope of this paper, we present an approach to detect large flows in real-time without even a short delay. After the detection of large flows, the next problem is how to control these large flows effectively and prevent network jam. In order to address this issue, we propose an approach in which when the controller is enabled, the large flow is mitigated the moment it hits the predefined threshold value in the control application. This real-time detection, marking, and controlling of large flows will assure an optimize usage of an overall network.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.23 no.4
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• pp.367-380
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• 2019

A 1kW-class horizontal axis wind turbine (HAWT) rotor blade is taken into account to investigate elastic characteristics in 2-D. The elastic blade field is composed of symmetric cross-ply laminated composite material. Blade element momentum theory is applied to obtain the boundary conditions pressuring the blade, and the plane stress elasticity problem is formulated in terms of two displacement parameters with mixed boundary conditions. For the elastic characteristics a fair of differential equations are derived based on the elastic theory. The domain is divided by triangular and rectangular elements due to the complexity of the blade configuration, and a finite element method is developed for the governing equations to search approximate solutions. The results describe that the elastic behavior is deeply influenced by the layered angle of the middle laminate and the stability of the blade can be improved by controlling the layered angle of laminates, which can be evaluated by the mathematical approach.

• Asian Journal of Business Environment
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• v.6 no.4
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• pp.13-17
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• 2016

Purpose - The purpose of this paper is to evaluate two multinational companies that seem to have reconciled the two mandates of CSR and profit maximization while becoming multibillion dollar companies and examine their organizational culture and practices and their management and leadership in order to determine the controlling factors, if any, that have elicited their success while renowned for their CSR policies. Research design, data, and methodology - This is a case study, an analytical approach, which focuses on exploring and analyzing the CSR policies of Starbucks and IKEA. Results - IKEA and Starbucks considered their position in the global business environment and their social responsibilities as crucial and did more than a cursory lip service to the issues. In fact, they both took the more difficult long-term approach and tried to resolve the root causes for the environmental and social issues in their supply chain. Ultimately though, it is the ethical leadership of the top management that sets the tone for the organizational culture and its CSR. Conclusion - IKEA and Starbucks are "living proof" that a company can be successful while treating its employees and the community of suppliers and associates with respect and dignity and while making this world a better place.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.11
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• pp.713-719
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• 2000

This paper presents an approach toward improving the performance of Moving Coil Type Linear Oscillatory Actuator (MC-LOA) with the application of Finite Element Method (FEM) to a simple control system. MC-LOA has an unbalanced magnetic circuit due to its asymmetric structure and there is a different flux distribution on the air-gap along the current direction. The interaction driven by two fluxes between the Permanent Magnet (PM) and the current causes the unbalanced thrust and interferes with the proper oscillation of MC-LOA. In order to solve the above problems and improve the driving performance, it is necessary to analyze the rate of the unbalanced thrust according to the current direction by using FEM. Then, the analysis results are used to determine the input currents for both directions. Controlling the input currents can be easily achieved by a simple control system, such as Pulse Width Modulation (PWM), without complex units. The validity of the approach is verified by the experimental results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.212-219
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• 2019

As unmanned aerial vehicle (UAV) has been utilized for military operation, efficient ways for controlling UAV has been necessary. In particular, instead of conventional approach using console control, speech recognition based UAV control is essential for military environments in which rapid command operation is required. But research on this novel approach is not actively studied yet. In this study, we introduce efficient ways of speech recognition system operation for voice-driven UAV control, focusing on mission command control from manned aircraft rather than ground control center. We propose an efficient way of system operation for UAV control in cooperation of aircraft and UAV, and verify its efficiency via speech recognition experiment.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.8
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• pp.47-55
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• 2022

The purpose of this study was to determine the relationship between company risk and factors such as business size, ownership structure, and leverage. The study was conducted on 142 manufacturing sector companies listed on the Indonesia Stock Exchange from 2013 to 2018. The purposive sampling method was used to select the research sample. The sample size for this study was 21 different companies. The analytical approach uses Structural Equation Modeling (SEM) with WarpPLS. According to the findings of the investigation, the size of the company has a significant influence on both the amount of leverage the company uses and the amount of risk the company takes. The level of leverage is significantly influenced by the ownership structure. However, the ownership structure does not have a significant impact on the level of risk the company; rather, leverage has a big impact on the level of risk the company faces. The findings of this study are helpful to prospective investors in measuring the risk posed by the company to make judgments regarding investments. The findings of this study are also essential for management to consider while controlling the risk of the organization.

• Geomechanics and Engineering
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• v.35 no.4
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• pp.425-436
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• 2023

An effective tool for researching actual problems in geotechnical and mining engineering is to conduct physical modeling tests using similar materials. A reliable geometric scaled model test requires selecting similar materials and conducting tests to determine physical properties such as the mixing ratio of the mixed materials. In this paper, a method is proposed to determine similar materials that can reproduce target properties using a polynomial model based on experimental results on modeling materials using a gypsum-sand mixture (GSM) to simulate rocks. To that end, a database is prepared using the unconfined compressive strength, elastic modulus, and density of 459 GSM samples as output parameters and the weight ratio of the mixing materials as input parameters. Further, a model that can predict the physical properties of the GSM using this database and a polynomial approach is proposed. The performance of the developed method is evaluated by comparing the predicted and observed values; the results demonstrate that the proposed polynomial model can predict the physical properties of the GSM with high accuracy. Sensitivity analysis results indicated that the gypsum-water ratio significantly affects the prediction of the physical properties of the GSM. The proposed polynomial model is used as a powerful tool to simplify the process of determining similar materials for rocks and conduct highly reliable experiments in a physical modeling test.