• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.5
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• pp.616-624
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• 2016

Design of shelter system requires consideration of noise at operators’ positions, because noise can injure person’s health. That is why studies which analyze and predict noise at operator’s positions is essential. To analyze noise sources of shelter system, this study measured noise of each equipment and obtained new equations by comparing the measured noise data and the equation which is relation noise and distance. The new equations predict noise level at operators’ positions. Actran analysis is performed to obtain noise level at operators’ positions too. At last, the noise level at operators’ positions measured in real shelter system is compared with the noise level predicted the new equations and Actran analysis.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.2 s.314
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• pp.1-9
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• 2007

In this paper, new results for perturbation bounds for unified decentralized systems by a unified approach using $\delta$ (defined as a shift operator at unified approach) are presented. Robust stability analysis of unified decentralized system is investigated by new robust stability bound under system uncertainties. New unified stability bounds are developed based on the unified Lyapunov matrix equation. It is shown that the system maintains its stability when new unified bounds are applied. Numerical example is presented to illustrate the proposed analysis.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.375-384
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• 2007

Parabolic approximation wave models based on $Pad{\acute{e}}$ approximants are presented of which the $Pad{\acute{e}}$(15, 15) is shown to be applicable to incidence angle $80^{\circ}$ in comparison with the exact solution of a constant sloping bed. After introducing a systematic way of the derivation to the parabolic wave equation, parabolic models are obtained in this study upto the 15th order and several numerical results are given to wave transformation in a constant sloping bed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.235-240
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• 1996

Forecasts of monthly landings of walleye pollock, Theragra chalcogramma, in Korea were carried out by the seasonal Autoregressive Integrated Moving Average(ARlMA) model. The Box - Cox transformation on the walleye pollock catch data handles nonstationary variance. The equation of Box - Cox transformation was Y'=($Y^0.31$_ 1)/0.31. The model identification was determined by minimum AIC(Akaike Information Criteria). And the seasonal ARlMA model is presented (1- O.583B)(1- $B^1$)(l- $B^12$)$Z_t$ =(l- O.912B)(1- O.732$B^12$)et where: $Z_t$=value at month t ; $B^p$ is a backward shift operator, that is, $B^p$$Z_t$=$Z_t$-P; and et= error term at month t, which is to forecast 24 months ahead the walleye pollock landings in Korea. Monthly forecasts of the walleye pollock landings for 1993~ 1994, which were compared with the actual landings, had an absolute percentage error(APE) range of 20.2-226.1 %. Thtal observed annual landings in 1993 and 1994 were 16, 61OM/T and 1O, 748M/T respectively, while the model predicted 10, 7 48M/T and 8, 203M/T(APE 37.0% and 23.7%, respectively).

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.3
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• pp.1-6
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• 2006

The altitude engine test is a sort of engine performance tests carried out to measure the performance of a engine at the simulated altitude and flight speed environments prior to that at the flight test. During the performance test of a engine, various values such as pressures and temperatures at different positions, air flow rate, fuel flow rate, and the load by thrust are measured. These measured values are used to derive the representative performance values such as the net thrust and the specific fuel consumption through a momentum equation. Hence each of the measured values has certain effects on the total uncertainty of the performance values. In this paper, the combined standard uncertainties of the performance variables at the engine test were estimated by the uncertainty analysis of the measurement values and the repeatability and reproducibility of the altitude test measurement were assessed by the analysis of variation on the repeated test data with different operator groups.

• Journal of the Korean Institute of Navigation
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• v.4 no.1
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• pp.31-50
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• 1980

It does not seem necessarily practicable to keep the system always in optimal condition, athough the control system of the follow-up mechanism on the most marine gyro compasses is to be adjusted by the operator through the gain adjustment. Sometimes a sustained oscillation or an incorrect gyro reading occurs to the system. For such a system any systematical research or theoretical basis of the guide for the optimal gain adjustment has not been reported yet. As a basic investigation of the theoretical system analysis to solve the problems concerned, the author attempts in this paper to express the system in a mathematical model deduced from the results of the theoretical approach and the experimental observation of each element contained in the follow-up mechanism of Hokshin D-1 gyro compass, and to constitute an over-all closed loop transfer function. This funciton being reverted to a fourth orderlinear differential equation, the first order simultaneous differential equations are obtained by means of the state-variables. The latter equations are solved by the Runge-Kutta method with digital computer. By comparing the characteristic of the simulated over-all output with that of the experimental result, it is shown that both outputs are nearly consistent with each other. It is also expected that the system representation proposed by this paper is valid and will be a prospective means in a further study on the design and optimal adjustment of the system.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.45-55
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• 2019

The purposes of this paper is to draw a conclusion on the impact of the characteristics of economic cooperation between china and south korea on customer value and enterprise performance in the korean electronics industry. In this paper, product reliability and product innovation are especially used as analytical factors, and this paper used a survey of 293 internal employees working in the electronics industry for analyze, and structural equation model(SEM) was used to analyze the data. The results of the research analysis are summarized as follows. First, it was found that the characteristic of economic cooperation in the research model has a significant effect on the product reliability. Second, it was found that the characteristics of economic cooperation have a significant effect on the products innovation. Third, the products reliability has a significant impact on customer value, while the products innovation has not affected customer value. Finally, it was found that the customer value of the korean electronics industry also has a significant impact on the Enterprise performance. As a good development alternative to this research, there is the ultimate goal of hoping that corporate managers will help to create new good values. To this end, we hope it will be helpful as we have made necessary suggestions to establish the desired direction of the Korean electronics industry operator.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.1009-1019
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• 2021

This study examined the effect of market sensing capability and information technology competency (IT competency) on innovation and competitive advantage in small and medium-sized tour operators (SMTOs). This research was conducted on the SMTOs located in three major cities for a tourism destination, meeting, and exhibition in East Java, Indonesia. 175 directors or managers of SMTOs were sampled using the purposive sampling technique. Data was obtained from directors or managers using a structured questionnaire. The empirical data was then analyzed by using Structural Equation Modeling (SEM). This study showed that market sensing capability positively and significantly affects innovation. Furthermore, competitive advantage was positively and significantly affected by market sensing capability. Although results showed that IT competence positively and significantly affects innovation, in contrast, it did not positively and significantly affect competitive advantage. These research findings suggest that market sensing capability and innovation have a substantial role in creating a competitive advantage for SMTOs facing the Revolution Industry 4.0 and a dynamic environment. Thus, innovation for SMTOs can be achieved by optimizing the role of market sensing capability and IT competency. However, this study also suggests that the capability or competence will not have any impact on competitive advantage if neither is optimized.

• Journal of Distribution Science
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• v.19 no.7
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• pp.113-121
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• 2021

Purpose: Technology induces the virtual distribution channel to exist, especially for booking a room online. This situation, indeed, provides an alternative for the customers to book based on their budget through digital platforms. One platform offering competitive prices is virtual hotel operators, such as Airbnb, OYO, RedDoorz, and Airy Rooms. Preferably, after using their platform, the user should be satisfied and loyal. Hence, this investigation aims to prove some associations. The first is between e-satisfaction and e-loyalty. The second is between website quality and e-satisfaction. The final is between website quality and e-loyalty. Research design, data, and methodology: This study is quantitatively designed with the sample of 350 users of the virtual hotel operator applications in Bandar Lampung: Airbnb, OYO, RedDoorz, and Airy, as the samples. Therefore, by denoting this sample size, the structural equation model based on covariance is utilized to examine the three hypotheses proposed. Also, to get the responses, this study uses a survey through a questionnaire. Result: This investigation demonstrates the positive relationship between e-satisfaction and e-loyalty. Additionally, website quality positively associates with e-satisfaction and e-loyalty. Conclusion: The virtual hotel operators must have the superiority on their website-based application to update the information based on the room availability and price, ensure online transaction safety, and facilitate its utilization to maintain long-term satisfaction and loyalty virtually.

• Journal of Korea Trade
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• v.23 no.3
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• pp.52-67
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• 2019

Purpose - This study analyzes the effect of the authorized economic operator-mutual recognition arrangement (AEO-MRA) on the performance of Korean exporters and importers. The effect of the import-export companies' characteristics, such as annual sales, the number of foreign markets, and overseas experience, on the AEO-MRA is deduced; the relationship between this effect and firm performance is analyzed. Design/methodology - An empirical research model was constructed and analyzed using structural equation modeling. The effect of AEO-MRA on logistics and operational performance was derived from the aforementioned characteristics as leading factors of the AEO-MRA. The regulatory influence of cooperation with logistics companies was analyzed in the AEO-MRA effect on logistics performance. Thus, 172 valid samples were obtained from import-export companies certified by the AEO-MRA. Findings - Among the aforementioned characteristics, only "annual sales" has a positive effect on the AEO-MRA, whose effect enhances logistics and operational performances. The AEO-MRA effect did not directly affect operational performance. Owing to the adjustment effect analysis, the AEO-MRA effect and logistics performance relationship is strengthened if the cooperative relationship with the logistics company is higher than a certain level. If this cooperation falls below a certain level, the AEO-MRA effect on logistics performance reduces. Thus, logistics cooperation is an important factor in the AEO-MRA effect and logistics performance relationship. Originality/value - Hinging on the resource-based theory and relational viewpoint, an empirical model that explains the relationship between the AEO-MRA effect and firm performance is established.