• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.429-438
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• 2003

The effects of fiber orientation on acoustic emission(AE) characteristics have been studied for the unidirectional and satin-weave, continuous glass-fiber reinforced plastic(UD-GFRP and SW-GFRP) tensile specimens. Reflection and transmission optical microscopy was used for investigation of the damage zone of specimens. AE signals were classified as different types by using short time fourier transform(STFT) : AE signals with high intensity and high frequency band were due to fiber fracture, while weak AE signals with low frequency band were due to matrix and interfacial cracking. The feature in the rate of hit-events having high amplitudes showed a process of fiber breakages, which expressed the characteristic fracture processes of individual fiber-reinforced plastics with different fiber orientations and with different notching directions. As a consequence, the fracture behavior of the continuous GFRP could be monitored as nondestructive evaluation(NDE) through the AE technique.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.436-440
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• 2008

Evaluating the work process of the organization is necessary to improve efficiency and make high quality of results. As size of construction projects are bigger, it is also applied to design firm. By applying efficient process, design team can reduce rework and waste. To make systematic process and keep a continuous progress, process evaluation is required. On this study, CMMI(Capability Maturity Model Integration) concept is benchmarked. Originally CMMI is suggested to evaluating capability of work process of Soft Ware developing organization by SEI(Software Engineering Institute). From CMMI system, direction of making evaluating method of design project performing team is drove. After worked out the evaluation method of capability maturity of process in design team, it could contribute making progress in the design process and satisfying client.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1441-1446
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• 2017

In recent, the studies on the systems have been progressing that count the number of people passing through passageway or count people who exist in specific space. The existing people counting systems count the number of people using ultrared sensors, ultrasonic sensors or camera sensors, which can be installed only on pillar or around wall. Though ultrared sensors and ultrasonic sensors is low cost, they are inadequate to detect incoming/outgoing when several pedestrians pass through passageway concurrently. In this paper, we designed a sensor mat using piezoelectric sensors to complement the above-mentioned disadvantage. Also, we implemented the system that detects direction of progress and counts the number of people. The sensor mat detects direction of progress using pressure given on sensors and timing information and counts the number of people when pedestrians pass through on a sensor mat.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1740-1746
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• 2013

Augmentative and alternative communication(AAC) is a communication tool for those with impairments or restrictions on the production or comprehension of spoken language. Traditional AAC has used a portable board with pictures and texts with which disabled person could be supported by it. Currently, smart phone based AAC researches and developments are actively studying. With emerging concepts of context-aware computing, the mobile devices can provide mobile users with timely information and location based services. We proposed a adjustable AAC system for disabled people of which has variable layouts and selectable items. We also implemented context-ware application for AAC systems including time, location and click count informations on smart phone. The system can adaptively change its layout and select AAC items depending on various situation of disabled persons.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.967-974
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• 2017

In this paper, a differential-braking-based yaw moment control system was developed to guarantee robust performance against road bank angle. A new target yaw rate model was established by combining the signal from a lateral acceleration sensor and 2-DOF single track model. In addition, a disturbance observer was utilized to take into account parameter uncertainties in yaw dynamics and to improve robust performance of the controller. CARSIM, which is a multi-DOF vehicle dynamic simulation tool, was used to verify the performance of the proposed controller in various driving scenarios. The simulation results indicate that the stability of the vehicle was robustly maintained by the controller, which is characterized by the reflection of the signal of a lateral acceleration sensor signal and by the compensation of the errors in the model parameters via the disturbance observer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.1009-1014
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• 2018

In this paper, we have designed and implemented a system that utilizes a radar sensor to measure distance between a sensor and objects. The sensor module creates raw data and uploads the data on the distance measuring system, which detects the presence of objects by using standard deviation and average filters. The experiment found that an algorithm using average filters measured people with error rates of up to 9.7 meters and a maximum error rate of 0.02 meters or less. While in an algorithm using standard deviations, it was found that an object is measured at an error rate of up to a maximum distance of 9.7 meters and a maximum error rate of 0.15 meters. Therefore, we have concluded that if a distance was measured by using a radar sensor, algorithms using average filters resulted in a higher accuracy than standard deviations filters.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.455-462
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• 2016

Recently, followed by rapid growth of robotics field, multi-linkage mechanism which can even pass by rough road is getting lots of attention. In this paper, I focused on Jansen mechanism. It's a kinematics object which is named after Dutch artist Theo jansen. Jansen mechanism embraces structure and mechanism which creates locomotion with the combination of the power and simple structure. Theo jansen suggests a 'Holy number'. It's an ideal ratio of leg components length. However, if there's desired gait locomotion, you have to adjust the ratio and the length. But even slight change of the length could cause a big change at the end-point. To solve this problem, I suggest a reverse engineering method to get a ratio of each links by nonlinear optimization with pre-set desired trajectory. First, we converted a movement of the joint of Jansen mechanism to vectors by kinematics analysis of multi-linkage structure. And we showed the trajectory at the end-point. After that, we set desired trajectory which we found most ideal. Then we got the length of the leg components which draws a trajectory as same as trajectory we set, using Multi-objective genetic algorithm toolbox in MATLAB. Result is verified by Edison designer and mSketch. And we analyzed if it could pass through the obstruction which is set dynamically.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.257-278
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• 2021

As the definition of the vendor-oriented implementation method, which was utilized in adopting an ERP system, has been centered around the project construction business, it was difficult for the EPR adopting organization to systematically prepare ERP projects and have enough deliberative opportunities to change-related policies. Furthermore, this method does not have a fully standardized construction process. Accordingly, by defining an organization that wants to adopt an ERP system as a customer, this paper develops the customer-based ERP construction process framework that assists both customers and developers who construct the system. For this purpose, this paper reviews the previous research and collects the construction processes of the commercial ERP SW vendor and ERP construction cases while proposing the three-layer process framework to construct ERP through the KJ method. The ERP process framework consists of 7 processes, 32 activities, 141 tasks while providing definitions for concepts of each component. Furthermore, the proposed processes and phases were set in order of the recommended execution, while the activities were suggested as an open-ended type so that the application and usability can be increased and polished by reflecting experts' opinions. The contribution of this study is to standardize the ERP project process by transforming the previous supplier-based ERP construction method into the customer-based one while providing important procedure and activity frameworks that apply to diverse ERP solutions per vendor. At the same time, this study provides an theoretical foundation to develop the construction process for the customer -based Cloud ERP. In practice, At the beginning of the ERP system construction project, it provides communication or process tailoring tools for the stakeholder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1486-1494
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• 2021

Character recognition is a technology required in various platforms, such as smart parking and text to speech, and many studies are being conducted to improve its performance through new attempts. However, with low-quality image used for character recognition, a difference in resolution of the training image and test image for character recognition occurs, resulting in poor accuracy. To solve this problem, this paper designed an end-to-end learning neural network that combines image super-resolution and character recognition so that the character recognition model performance is robust against various quality data, and implemented an alternative whole learning algorithm to learn the whole neural network. An alternative end-to-end learning and recognition performance test was conducted using the license plate image among various text images, and the effectiveness of the proposed algorithm was verified with the performance test.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.317-318
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• 2022

In accordance with global decarbonization, optimization and productivity improvement using digital twin are being sought, and software development for optimizing ship and marine energy operation is accelerating by selecting digital twin as a future core technology. In order to reduce the operating cost of ships and strengthen the competitiveness of the shipbuilding industry due to the international strengthening of regulations on carbon emissions, it is necessary to predict the carbon emission of ships in advance and provide a carbon reduction operation solution. A plan was carried out for the development of open digital platform technology and the establishment of an environment to support the securing of carbon transparency of the ship and offshore system.