• Korean Journal of Remote Sensing
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• v.19 no.2
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• pp.99-106
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• 2003

The shoreline changes were observed and analysed using the video image by a remote unmanned automatic camera monitoring system installed at Haeundae beach of Busan City. In order to analyse quantitatively the shoreline changes caused by waves and tides, the image averaging technique and the rectification technique for obliquely acquired image were applied to the video image during the typhoon Bart in September, 1999. The results showed that the camera monitoring system can be used as a very cost effective and efficient tool for monitoring shorelines which change continuously due to waves and tides.

• Journal of applied mathematics & informatics
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• v.37 no.5_6
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• pp.357-382
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• 2019

In this paper, we consider boundary value problem for a weakly coupled system of two singularly perturbed differential equations of convection diffusion type with discontinuous source term. In general, solution of this type of problems exhibits interior and boundary layers. A numerical method based on streamline diffusiom finite element and Shishkin meshes is presented. We derive an error estimate of order $O(N^{-2}\;{\ln}^2\;N$) in the maximum norm with respect to the perturbation parameters. Numerical experiments are also presented to support our theoritical results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.2
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• pp.108-113
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• 2019

Due to the special structure of the car seat, the heating and cooling module must be installed in a limited area resulting in difficulty in regards to achieving optimal cooling and heating efficiency. In order to solve these problems, this paper establishes a new structure for heating and cooling modules, verifies the structural feasibility of the thermoelectric module for cooling and heating the seat through fluid simulations, and verifies the proper design of the mechanical components of the thermoelectric module.

• International Journal of Aerospace System Engineering
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• v.6 no.1
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• pp.1-7
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• 2019

In the present study, structural safety and stability on the main wing and tail planes of the 1.2 ton WIG(Wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The carbon-epoxy composite material was used in design of wing structure. The skin-spar with skin-stressed structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, the design load was estimated with maximum flight load. From static strength analysis results using finite element method of the commercial codes. From the stress analysis results of the main wing, it was confirmed that the upper skin structure between the second rib and the third rib was unstable for the buckling load. Therefore in order to solve this problem, three stiffeners at the buckled region were added. After design modification, even though the weight of the wing was a little bit heavier than the target weight, the structural safety and stability was satisfied for design requirements.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.119-126
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• 2022

This paper presents a method to reduce the vibration-induced noise effect of an inertial measurement device mounted on a self-driving vehicle. The inertial sensor used in the GNSS/INS integrated navigation system of a self-driving vehicle is fixed directly on the chassis of vehicle body so that its navigation output is affected by the vibration of the vehicle's engine, resulting in the degradation of the navigational performance. Therefore, these effects must be considered when mounting the inertial sensor. In order to solve this problem, this paper proposes to use an in-house manufactured vibration suppression device and analyzes its impact on reducing the vibration effect. Experimental test results in a static scenario show that the vibration-induced noise effect is more clearly observed in the lateral direction of the vehicle, but can be effectively suppressed by using the proposed vibration suppression device compared to the case without it. In addition, the dynamic positioning test scenario shows the position, speed, and posture errors are reduced to 74%, 67%, and 14% levels, respectively.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.40-46
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• 2022

Recently, as the need for data access by integrating information in a distributed cloud environment increases in enterprise-wide enterprises, interoperability for collaboration between existing legacy systems is emphasized. In order to interconnect independent legacy systems, it is necessary to overcome platform heterogeneity and semantic heterogeneity. To solve this problem, middleware was built using EMRA (Extended MetaData Registry Access) based on ISO/IEC 11179. However, the designed middleware cannot guarantee the efficiency of information utilization because it does not have an adjustment function for each node's resource status and work status. Therefore, it is necessary to manage and adjust the legacy system. In this paper, we coordinate the correct data access between the information requesting agent and the information providing agent, and integrate it by designing a cooperative agent responsible for information monitoring and task distribution of each legacy system and resource management of local nodes. to make efficient use of the available information.

• Journal of Multimedia Information System
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• v.9 no.2
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• pp.103-112
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• 2022

Background: A presentation attack places the printed image or displayed video at the front of the sensor to deceive the biometric recognition system. Usually, presentation attackers steal a genuine user's biometric image and use it for presentation attack. In recent years, reconstruction attack and adversarial attack can generate high-quality fake images, and have high attack success rates. However, their attack rates degrade remarkably after image shooting. Methods: In order to comprehensively analyze the threat of presentation attack to palmprint recognition system, this paper makes six palmprint presentation attack datasets. The datasets were tested on texture coding-based recognition methods and deep learning-based recognition methods. Results and conclusion: The experimental results show that the presentation attack caused by the leakage of the original image has a high success rate and a great threat; while the success rates of reconstruction attack and adversarial attack decrease significantly.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.679-686
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• 2023

According to the PSPC (Performance Standard for Protective coatings) rule, the edge preparation must keep 2R or 3-pass grinding. The stiffener plate edge grinding of the ship inside is manually progressed by worker and worked with just one pass grinding. In addition, the poor working condition cause grinding workers to avoid working in them, and the quality is determined by the skill-level of a worker. This research developed optimal tool for edge milling. In order to milling various collar plates edge, this research developed vision system that can recognize the edge points and it developed a program that operator can adjust the amount of cutting and speed, and add various features so that milling quality would be improved. So, this research focused on overcoming the difficulties in working condition and development of automated milling machine for ship stiffener plate.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.32-46
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• 2023

Recently, small and medium-sized manufacturing companies have shown increased interest in and participation in smart factories in order to survive in market competition. However, many SMEs build smart factories without a systematic review or preparation, which leads to them not being able to use them properly. This study considers the main reason for the low utilization rate of smart factories to be a lack of sufficient reflection of user requirements. Therefore, a method and procedure for deriving the priority of smart factory requirement functions and operating performance indicators based on QFD is proposed as a solution to this issue.

• Journal of Wind Energy
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• v.4 no.2
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• pp.17-24
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• 2013

Idealized PID-controlled rotor-speed error for blade pitch control of wind turbines responds as a second-order system with natural frequency and damping ratio for closed-loop system. RISO National Laboratory has recommended specific natural frequency(=0.6 rad/s) and damping ratio(=0.7) for 2 MW wind turbine. The baseline controller for 5 MW wind turbine of NREL(National Renewable Energy Laboratory) is designed based on the same values of RISO recommendation. This study investigates the effect of the natural frequency and damping ratio of the controller for NREL 5 MW wind turbine. It is confirmed that RISO recommendation shall be tuned for each wind turbine.