• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.277-282
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• 2006

It is well known that Kalman filtering is an optimal real-time data fusion method for GPS/INS integration. However, it has some limitations in terms of stability, adaptability and observability. A Kalman filter can perform optimally only when its dynamic model is correctly defined and the noise statistics for the measurement and process are completely known. It is found that estimated Kalman filter states could be influenced by several factors, including vehicle dynamic variations, filter tuning results, and environment changes, etc., which are difficult to model. Neural networks can map input-output relationships without apriori knowledge about them; hence a proper designed neural network is capable of learning and extracting these complex relationships with enough training. This paper presents a GPS/INS integrated system that combines Kalman filtering and neural network algorithms to improve navigation solutions during GPS outages. An Extended Kalman filter estimates INS measurement errors, plus position, velocity and attitude errors etc. Kalman filter states, and gives precise navigation solutions while GPS signals are available. At the same time, a multi-layer neural network is trained to map the vehicle dynamics with corresponding Kalman filter states, at the same rate of measurement update. After the output of the neural network meets a similarity threshold, it can be used to correct INS measurements when no GPS measurements are available. Selecting suitable inputs and outputs of the neural network is critical for this hybrid method. Detailed analysis unveils that some Kalman filter states are highly correlated with vehicle dynamic variations. The filter states that heavily impact system navigation solutions are selected as the neural network outputs. The principle of this hybrid method and the neural network design are presented. Field test data are processed to evaluate the performance of the proposed method.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.62-69
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• 2014

Infrared signature of rocket plume plays an important role for detection, recognition, tracking and minimzing for low observability. Infrared signatures of rocket plume with reduced smoke propellant and smokeless propellant are measured. In order to estimate the infrared signature of rocket plume, CFD analysis for flow structure of plume is performed, and layered integration method for estimating of infrared signature is used. Numerical and experimental results were in good agreement. Both propellants had similar infrared signature. Strong peak at $4.3{\mu}m$ region in the experimental results is appeared due to experimental error arising from the calibration procedure.

• Journal of Convergence for Information Technology
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• v.8 no.4
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• pp.219-224
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• 2018

The purpose of this paper is to analyze the influence of marketing capabilities on business performance among SMEs. The results suggest that complexity, trialability, and observability are among the technological factors that have a significant influence on ICT adoption. Research advantage and compatibility do not influence ICT adoption. Meanwhile, organizational factors such as owner/manager knowledge and innovativeness significantly influence ICT adoption among SMEs. Environmental factors such as competitive pressure, institutional intervention contribute significantly to the adoption. Moreover, data analysis reveals that ICT adoption has a positive influence toward SMEs' marketing capabilities. Finally marketing capabilities significantly influence a firm's business performance.

• Industry Promotion Research
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• v.9 no.1
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• pp.65-79
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• 2024

This study analyzed the failure cases of new products for relative benefits among various factors related to the characteristics of innovation, which is an important factor in the consumer persuasion process among Rogers (1995)'s innovation diffusion theory. This is because relative profits are the most influential factor in consumers' intention to adopt among the characteristics of various innovative products (Holak and Lenmann, 1990). As a result of analyzing the failure cases of new products of six companies, these products lacked relative profits for existing products in common. Relative profits are factors that are measured in the economic sense or are measured by social advantages, convenience, and satisfaction, and are the most important factors compared to other factors such as suitability, complexity, observability, and applicability. In the end, it was found that relative profits compared to existing products are an important success factor in persuading consumers of new products.

• Journal of Digital Convergence
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• v.18 no.5
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• pp.441-453
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• 2020

This study conducted a questionnaire survey on SNS users who are conducting K-POP record collection activities using SNS and verified factors affecting the intention to continue K-POP record collection activities. The main methods of analysis were exploratory factor analysis, confirmatory factor analysis, correlation analysis, and path analysis using SPSS 21.0 program and AMOS 21.0 program. The results are summarized as follows. First, compatibility for K-POP record collection activities through SNS has a positive effect on perceived usefulness, and observability also has a positive effect on perceived usefulness and perceived ease of use. Second, perceived ease of use for K-POP records collection using SNS has a positive effect on perceived usefulness. Third, perceived usefulness and perceived ease of use for K-POP records collection using SNS have a positive effect on continuous intention of K-POP records collection activity through SNS. As a result of this study, it suggests that the intention to continue the collection activities of K-POP records using SNS can be explained through the integration of innovation diffusion theory and technology acceptance model.

• Science of Emotion and Sensibility
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• v.10 no.1
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• pp.13-21
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• 2007

Many companies launched convergence products that are merged with several functions. Mobile convergence has some advantages such as portable convenience, usability of use, economic advantage that takes parts of the common component among products in the aspects of the digital products. Even though a plenty of items launched by convergence boom in the market, not tons of convergence products succeeded in the market because One of the major reasons is that companies don't take consumer evaluations in the process of the product development. It is important to set up infrastructure and excellent quality of the products for lasting the lifecycle of the convergence items. But, above all, it is imperative to find out how consumers evaluate convergence products and what they are affected to meet their satisfaction. Nevertheless, there are few case studies about consumer evaluations in mobile convergence until now. This study is to find out how consumers evaluate convergence products and what is the factor. This study surveyed 158 subjects and used multi-regression analysis and ANOVA(analysis of variance). The results of this study show that factors such as relative advantages, complexity, observability, perceived convenience affect the attitude of consumers.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.285-293
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• 2020

In this paper, to improve Synthetic Aperture Radar (SAR) image quality, the effect of time synchronization error in the EGI/IMU (Embedded GPS/INS, Inertial Measurement Unit) integrated system is analyzed and state augmentation is applied to compensate it. EGI/IMU integrated system is widely used as a SAR motion measurement algorithm, which consists of EGI mounted to obtain the trajectory and IMU mounted on the SAR antenna. In an EGI/IMU integrated system, a time synchronization error occurs when the clocks of the sensors are not synchronized. Analysis of the effect of time synchronization error on navigation solutions and SAR images confirmed that the time synchronization error deteriorates SAR image quality. The state augmentation is applied to compensate for this and as a result, the SAR image quality does not decrease. In addition, by analyzing the performance and the observability of the time synchronization error according to the maneuver, it was confirmed that the time-variant maneuver such as rotational motion is necessary to estimate the time synchronization error adequately. In order to reduce the influence of the time synchronization error on the SAR image, the time synchronization error must be compensated by performing maneuver changing over time such as a rotation before SAR operation.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.71-79
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• 2018

This study discussed the meaning of a drone, and especially drone journalism and legal and ethical issues around that, at an introductory dimension, which is used in various social bases, but is still just an academic discussion at the beginning stage. As a methodology, content analysis was used. It seems that drone journalism has high diffusibility as a technology with high 'relative advantage', 'compatibility', 'trial ability' and 'observability' and low 'complexity' in terms of the diffusion of innovation theory. However, it will be very likely that controversies will be raised, such as safety issue due to collision and crash, a dispute over violation of privacy that may seriously infringe privacy like individual portrait rights and a controversy about the accuracy and source of information as drone filming low price and ease of use. Suggest solutions to legal and ethical issues based on existing research. Technical stability is required. Also, it is necessary to change the awareness of journalists about the drones coverage and to educate ethics, and it is necessary to establish social public opinion on issues such as privacy violation and establish system and legal measures through it. Future research is expected to carry out empirical research including journalists and public awareness surveys.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.2
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• pp.14-25
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• 1999

The IEEE standard 1149.1, which was proposed to increase the observability and the controllability in I/O pins, makes it possible the board level testing. In the boundary-scan environments, many shift operations are required due to their serial nature. This increases the test application time and the test application costs. To reduce the test application time, the method based on the parallel opereational multiple scan paths was proposed, but this requires the additional I/O pins and the internal wires. Moreover, it is difficult to make the designs in conformity to the IEEE standard 1149.1 since the standard does not support the parallel operation of data shifts on the scan paths. In this paper, the multiple scan path access algorithm which controls two scan paths simultaneously with one test bus is proposed. Based on the new algorithm, the new algorithm, the new board level BIST architecture which has a relatively small area overhead is developed. The new BIST architecture can reduce the test application time since it can shift the test patterns and the test responses of two scan paths at a time. In addition, it can reduce the costs for the test pattern generation and the test response analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.109-117
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• 2015

Aircraft needs an inlet duct to supply the airflow to engine face. A fighter aircraft that requires low radar observability has to hide the engine face in the fuselage to reduce the Radar Cross Section(RCS). Therefore, the flow path of the inlet duct is changed into S-shape. The performance of the aircraft engine is known to be influenced by the shape and the centerline curvature of the S-Duct. In this study, CFD analysis of the RAE M 2129 S-Duct has been performed to investigate the influence of aspect ratio of inlet geometry. The performance of the S-Duct is evaluated in terms of the distortion coefficient. To simulate the flow under adverse pressure gradient better, $k-{\omega}SST$ turbulence model is employed. The computational results are validated with the ARA experimental data. The secondary flow and the flow separation are observed for all computational cases, while the semi-circular geometry has been found to produce the best results.