• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.298-303
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• 2013

Magnetic abrasive polishing is one of the most promising finishing methods applicable to complex surfaces. Nevertheless this process has a low efficiency when applied to very hardened materials. For this reason, EP-MAP hybrid process was developed. EP-MAP process is expected to machine complex and hardened materials. In this research, deburring process using EP-MAP hybrid process was proposed. EP-MAP deburring process is applied to micro channel, thereby it can obtain both deburring process and polishing process. EP-MAP deburring process on the micro channel was performed. Through design of experiment method, error of height in this process according to process parameter is analyzed. When the level 1 parameter A(magnetic flux density) and level 2 parameter B(electric potential), C(working gap) and level 3 parameter D(feed rate) are applied in the deburring process using EP-MAP hybrid process, it provides optimum result of EP-MAP hybrid deburring process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.114-120
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• 2013

An EP(Electrolytic Polishing)-MAP(Magnetic Abrasive Polishing) hybrid process was applied to remove burr on the micro pattern. Micro pattern fabrication processes are combined with micro milling and EP-MAP hybrid process for deburring. Depending on the micro milling conditions which are applied, micro burrs are formed around the side and top of the pattern. The EP-MAP deburring is used to remove these burrs effectively. To optimize removal rate and form error in the EP-MAP hybrid process, a design of experiment was performed. The effect of deburring process and form error of micro pattern are evaluated via SEM images and the results of AFM.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.54-60
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• 2006

A method for generating the compressor map from some performance measuring data using the hybrid intelligent technique was newly proposed. In order to improve accuracy of the traditional scaling method, a method to generate the compressor map using the GAs(Genetic Algorithms) was previously proposed, but the method has a drawback that it can not find correctly surge and choke points of the compressor map. However, the proposed hybrid intelligent method can determine obviously those points as well as improve the accuracy of the compressor map through complementarily using the GAs and the scaling method.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.27-34
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• 2013

Mobile robot has the exploration function in order to perform its own task. Robot exploration can be used in many applications such as surveillance, rescue and resource detection. The workspace that robots performed in was complicated or quite wide, the multi search using the several mobile robots was mainly used. In this paper, we proposed a scheme that all areas are searched for by using one robot. The method to be proposed extract a area that can be explored in the workspace then the robot investigates the area and updates the map at the same time. The explored area is saved as a hybrid map that combines the nice attributes of the grid and topological maps. The robot can produce the safe navigation route without the obstacles by using hybrid map. The proposed hybrid map uses less memory than a grid map, but it can be used for complete coverage with the same efficiency of a topological map. Experimental results show that the proposed scheme can generate a map of an environment with only 6% of the memory that a grid map requires.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.4_1
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• pp.335-341
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• 2014

The main goal of this study is on developing a proper brand-new data of national base map and Data Based(DB) model for new information technology environments. To achieve this goal, we generated a brand-new Hybrid spatial information model which is specialized in the spatio-temporal map structure, the framework map for information integration, and the multiple-layered topology structure. The DB structure was designed to reflect the change of objections by adding a new dimension of 'time' in the spartial information, while the infrastructure was able to connect/converge with other information by giving the unique ID and multi-scale fusion map structure. Furthermore, the topology and multi visualization structure, including indoor and basement information, were designed to overcome limitations of expressing in 2 dimension map. The result from the performance test, which was based on the Hybrid spatial information model, confirms the possibility in advanced national base map and conducted DB model through implementing various information and spatiotemporal connections.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.418-429
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• 2013

This paper presents a GIS vector map data compression scheme based on hybrid polyline simplification method and SEC(spatial energy compaction). The proposed method extracts all layers which contain polylines in the GIS vector map and compress all polylines in extracted layers by the hybrid polyline simplification and SEC based on MAE(minimum area error) for each segment in the line. The proposed simplification and SEC increase the compression ratio while preserving the shape quality. We analyze the visual aspects and compression efficiency between the original GIS vector map and the compressed map. From experimental results, we verify that our method has the higher compression efficiency and visual quality than conventional methods.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.10
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• pp.970-976
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• 2012

In this paper, a single LRF has been used to produce a 3D map for the mobile robot navigation. The 2D laser scanners are used for mobile robots navigation, where the laser scanner is applied to detect a certain level of area by the straight beam. Therefore it is limited to the usages of 2D obstacle detection and avoidance. In this research, it is designed to complement a mobile robot system to move up and down a single LRF along the yaw axis. During the up and down motion, the 2D data are stacked and manipulated to build a 3D map. Often a single LRF data are mixed with Gaussian and impulse noises. The impulse noises are removed out by the hybrid median filter designed in this research. The 2D data which are improved by deleting the impulse noises are layered to build the 3D map. Removing impulse noises while preserving the boundary is a main advantages of the hybrid median filter which has been used widely to improve the quality of images. The effectiveness of this hybrid median filter for rejecting the impulse noises has been verified through the real experiments. The performance of the hybrid median filter is evaluated in terms of PSNR (Peak Signal to Noise Ratio) and the processing time.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.47-56
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• 2003

Geometric cutting-simulation and verification play an important role in detecting NC machining errors in mold & die manufacturing and thereby reducing correcting time & cost on the shop floor. Current researches in the area may be categorized into view-based, solid-based, and discrete vector-based methods mainly depending on workpiece models. Each methodology has its own strengths and weaknesses in terms of computing speed, representation accuracy, and its ability of numerical inspection. The paper proposes a hybrid modeling scheme for workpiece representation with z-map model and discrete vector model, which performs 3-axis and 5-axis cutting-simulation via tool swept surface construction by connecting a sequence of silhouette curves.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.101-107
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• 2014

Mobile robots use an environment map of its workspace to complete the surveillance task. However grid-based maps that are commonly used map format for mobile robot navigation use a large size of memory for accurate representation of environment. In this reason, grid-based maps are not suitable for path planning of mobile robots using embedded board. In this paper, we present the path planning algorithm that produce a secure path rapidly. The proposed approach utilizes a hybrid map that uses less memory than grid map and has same efficiency of a topological map. Experimental results show that the fast path planning uses only 1.5% of the time that a grid map based path planning requires. And the results show a secure path for mobile robot.

• Journal of Information Processing Systems
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• v.13 no.1
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• pp.68-82
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• 2017

Nowadays, geographic information system (GIS) is developed and implemented in many areas. A huge volume of vector map data has been accessed unlawfully by hackers, pirates, or unauthorized users. For this reason, we need the methods that help to protect GIS data for storage, multimedia applications, and transmission. In our paper, a selective encryption method is presented based on vertex randomization and hybrid transform in the GIS vector map. In the proposed algorithm, polylines and polygons are focused as the targets for encryption. Objects are classified in each layer, and all coordinates of the significant objects are encrypted by the key sets generated by using chaotic map before changing them in DWT, DFT domain. Experimental results verify the high efficiency visualization by low complexity, high security performance by random processes.