• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.193-198
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• 2004

In order to keep the market competitiveness, it is desirable for automotive manufacturer to meet the customer's various aspects of requirements. The overall NVH (Noise, Vibration, and Harshness) performance has been an important measure when evaluating overall vehicle performance, product quality, and enhancing customers' loyalty to the product. The noise and vibration, while the engine is idling, has been brought particular attention to the drivers and passengers, because they encounter the operation conditions quite frequently without other masking noise sources: wind noise, road noise, and even powertrain radiated noise at higher speed driving. The specific noise, defined as 'CHIT' noise, has been identified as a potential customer issue, from the Pickup Truck with newly developed V8 powertrain. This paper describes the definition of the noise, identifying the potential sources, and noise radiation mechanisms, based on series of powertrain and vehicle test and verification processes. Then, based on the root-cause identified, the design change has been proposed and validated with several vehicles in order to have a complete satisfaction of the customer.

• Smart Structures and Systems
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• v.7 no.5
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• pp.365-378
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• 2011

Piezo-based active structural health monitoring (SHM) requires amplifiers specifically designed for capacitive loads. Moreover, with the increase in number of applications of wireless SHM systems, energy efficiency and cost reduction for this type of amplifiers is becoming a requirement. General lab grade amplifiers are big and costly, and not built for outdoor environments. Although some piezoceramic power amplifiers are available in the market, none of them are specifically targeting the wireless constraints and low power requirements. In this paper, a piezoceramic transducer amplifier for wireless active SHM systems has been designed. Power requirements are met by two digital On/Off switches that set the amplifier in a standby state when not in use. It provides a stable ${\pm}180$ Volts output with a bandwidth of 7k Hz using a single 12 V battery. Additionally, both voltage and current outputs are provided for feedback control, impedance check, or actuator damage verification. Vibration control tests of an aluminum beam were conducted in the University of Houston lab, while wireless active SHM tests of a wind turbine blade were performed in the Harbin Institute of Technology wind tunnel. The results showed that the developed amplifier provided equivalent results to commercial solutions in suppressing structural vibrations, and that it allows researchers to perform active wireless SHM on moving objects with no power wires from the grid.

• Journal of Distribution Science
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• v.19 no.6
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• pp.5-19
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• 2021

Purpose: O2O Service is a major internet-based distribution industry. The purpose of this study is to confirm the effects of positive psychological capital on job intensity, customer orientation, and the mediating effects of trust of O2O employee. Research design, data and methodology: This study aims to identify the effect of positive psychological capital on customer orientation and job intensity through empirical analysis. 475 questionnaires were used for the final analysis using random sampling methods from O2O employees working at leading distribution companies for hypothesis verification. The analysis methods used for hypothesis testing in this study were analyzed using the SPSS 21.0 statistical package. Results: Empirical analysis shows that it is an important factor in increasing job intensity and customer orientation, and that company trust has a significant influence through mediating effects among variables. Conclusions: In order to enhance job intensity and customer orientation for O2O distribution workers, it is necessary to change efforts with management efforts for positive psychological factors and trust. It is also believed that company trust should be considered as an important factor in the future leadership competency development system in that it can promote positive psychological capital, further strengthening job intensity and customer orientation.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.475-484
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• 2021

The Android OS has quickly established itself with the smartphone market and is being applied in a variety of ways such as navigation and refrigerator panels. Existing terminals can implement services that require high precision while using RTOS that requires accurate execution time, but Android OS has a disadvantage in that it cannot provide high-precision real-time performance. In this paper, we propose a real-time communication method that operates in the Android OS. Real-time communication reduces the load using the UDP protocol, and configures the real-time operating system time tick through a high-precision timer in the kernel area. An Android application level library was created to implement real-time communication and compared with the existing Android library for real-time performance verification.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.8
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• pp.497-502
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• 2021

This study aims to investigate the determinants of default risk of rural banks in East Java, Indonesia. The method used is descriptive verification and logistic regression analysis. The data used is secondary in the form of monthly annual financial reports of rural banks in East Java during the period 2009-2018. From the results, it was shown that net interest margin (NIM) as a proxy of market risk, non-performing loan (NPL) as a proxy of credit risk, operation efficiency as a proxy of operational risk and return on assets (ROA) as a proxy of profitability have a significant influence on default risk. Meanwhile, the loan to deposit (LDR) ratio as a proxy of liquidity risk has no significant influence on default risk. Banks need to implement risk management and meet the capital adequacy requirements of regulators so that they are resistant to risk, and also, compliant with bank governance to be able to produce high returns for rural banks have an impact on sustainability and its existence. The ability to identify setbacks in bank conditions and the ability to distinguish between healthy and problematic banks will enable to anticipate default banks.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.177-187
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• 2021

The global economy has been very difficult due to the recent impact of COVID-19. Korea is also pushing for strong quarantine policies such as K- quarantine and social distancing, but the economy is hardly recovering. In particular, the economic situation began to change rapidly depending on the export and domestic market, the public's interest in the economy increased, and companies became more sensitive. In order to estimate this rapidly changing economic situation, major advanced countries have also developed models that can periodically monitor the economy at the government level. Through this, by periodically reporting the economic trends, the public and companies can be aware of the economic trends to some extent. This study analyzed the cases of weekly business trends in advanced countries and developed a model of weekly economic activity suitable for Korea. To verify this, indices closely related to the economy such as mobility, industrial activity, face-to-face consumption, and psychology were discovered and estimated. As a result of the study, the weekly economic activity index was judged to be very useful in capturing short-term real economic activity. In the future, in order to secure the robustness and stability of the index and to increase the reflection of reality, model improvement and parameter estimation should be performed regularly.

• The Journal of Economics, Marketing and Management
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• v.10 no.4
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• pp.13-24
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• 2022

Purpose: Although numerous research has covered content on trends in the adoption and use of wearable devices, their uses across several sectors such as healthcare, gaming, and fashion, there seems to be a considerable paucity with regard to empirical research focusing on the solutions for factors that undermine the effectiveness of wearable devices in healthcare. The present research aims to highlight what has been covered on wearable devices in healthcare while highlighting the limitations for future research. Research design, data, and methodology -The present authors conducted one of the most famous qualitative literature approach which has been called as PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement. The selecting criteria for eligible prior studies was estimated by whether studies are suitable for the current research, identifying they are peer-reviewed and issued by notable publishers between 2017 and 2022. Result - Our results indicated that (1) Increasing the Affordability and User Education on Wearable Devices in Healthcare (2) Tackling the Technological Issues in Wearable Devices to Promote Healthcare Delivery (3) Solving Security and Privacy Issues Associated with Wearable Devices (4) Promoting Standards and Appropriate Regulations for Wearable Devices. Conclusion - To add, resolving the technological issues associated with wearable devices in healthcare will ensure that the new devices in the market will have longer battery life, multiple functions, and enhanced accuracy, thus ensuring that patients receive better care. Necessary interventions are taken on time to avoid any deleterious consequences such as proliferating mortality rates among the different patient groups.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.2
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• pp.87-93
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• 2022

[¹⁸F]FDG is known as the most widely used radiopharmaceutical in the imaging field of nuclear medicine worldwide. With the introduction of PET equipment, the demand for [¹⁸F]FDG has increased and the production volume has also increased. However, in order to increase production, the use of ¹⁸F radioisotope must be increased or [¹⁸F]FDG must be synthesized in high yield. Therefore, in order to meet the high yield and purity of radiopharmaceuticals, a radiopharmaceutical automatic synthesizer was required. As the use of [¹⁸F]FDG increased, automated synthesizer manufacturers supplied various types of radiopharmaceutical automated synthesizers to the market. In this study, we developed a commercialized [¹⁸F]FDG radiopharmaceutical automatic synthesizer (sCUBE FDG) using a disposable cassette type that complies with GMP developed by FutureChem, a leading radiopharmaceutical company. We used sCUBE FDG to verify the production process, radiopharmaceutical's quality (radiochemical purity, etc.), and radiochemical yield of [¹⁸F]FDG. As a result of optimizing the automatic synthesis process and synthesizing a total of 30 times, the production time was 35 ± 3 minutes and the average production yield was 65.6%.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.157-164
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• 2009

As computer industry has been rapidly developed since 1980's, it has been highly increasing to use M&S. The use of M&S can reduce development cost, time to market, and so on, and using it we can get the results of experiments which are impossible to test in real environments. But there is an important precondition on the dependability of M&S which is being developed or used. In this paper, We introduce the Key concepts of VV&A, and so forth, and We finally present the DM&S VV&A application and promotion method.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.spc1
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• pp.97-107
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• 2024

Efforts to respond to climate change are being made in various ways around the world, and in the energy field, continuous research and pilot projects are underway through new and renewable energy, efficient power grid management, and power grid services. Systems are in place to realize these efforts, and the systems created allow for better effectiveness. When implementing a system, systems engineering methodology helps design a more systematic system and can provide verification accuracy and uniformity through intuitive connectivity. In this paper, the original requirements of the power grid stabilization system and the architecture of the system's essential constraints are constructed as a conceptual model and the boundaries and flows between components are defined. By utilizing distributed resources such as EV(Electric Vehicle) and ESS(Energy Storage System) in the power service platform system, we plan to design and build a next-generation power service system that can participate in the power stabilization market and implement a system necessary to respond to climate change in the future.