• Journal of Institute of Control, Robotics and Systems
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• v.19 no.5
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• pp.468-472
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• 2013

This paper deals with the indoor localization problem for a SSMR (Skid Steering Mobile Robot) subjected to wheel-ground friction and with one LRF (Laser Range Finder). In order to compensate for some friction effect, a friction related coefficient is estimated by the recursive least square algorithm and appended to the maneuvering command. Also to reduce odometric information based localization errors, the lines are extracted with scan points of LRF and matched with the ones of the corresponding map built in advance. The present friction compensation and scan map matching schemes have been applied to a laboratory SSMR, and experimental results are given to validate the localization performance along an indoor corridor.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.267-274
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• 2015

In the semiconductor manufacturing post-FAB process, predicting a package test result accurately in the wafer testing phase is a key element to ensure the competitiveness of companies. The prediction of package test can reduce unnecessary inspection time and expense. However, an analysing method is not sufficient to analyze data collected at wafer testing phase. Therefore, many companies have been using a summary information such as a mean, weighted sum and variance, and the summarized data reduces a prediction accuracy. In the paper, we propose an analysis method for Wafer Map Image collected at wafer testing process and conduct an experiment using real data.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.99-107
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• 2004

This paper considers reinforcement learning control with the self-organizing map. Reinforcement learning uses the observable states of objective system and signals from interaction of the system and the environments as input data. For fast learning in neural network training, it is necessary to reduce learning data. In this paper, we use the self-organizing map to parition the observable states. Partitioning states reduces the number of learning data which is used for training neural networks. And neural dynamic programming design method is used for the controller. For evaluating the designed reinforcement learning controller, an inverted pendulum of the cart system is simulated. The designed controller is composed of serial connection of self-organizing map and two Multi-layer Feed-Forward Neural Networks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.801-805
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• 2000

This paper presents a new method of tool path optimization. A NC verification model based Z-map was utilized to obtain chip load in feed per tooth. This developed software can regenerate a NC program from cutting condition and the NC program that was generated in CAM. The regenerated NC program has not only all same data of the ex-NC program but also the new feed rates in every block. The new NC data can reduce the cutting time and manufacture precision dies with the same chip load in feed per tooth. This method can also prevent tool chipping and make constant tool wear. This paper considered the effects of acceleration and deceleration in feed rate change.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.643-645
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• 2000

This paper puts emphasis on navigation in virtual environment, which is one of the major interfaces for the interactivity between human and virtual environment in virtual reality circumstances and worlds. It proposes a new navigation method: 2d Map-Based navigation, which prevents user's spatial lost in 3D Virtual Environment. The 2D Map-Based Navigation is composed of three major processes, Constant Velocity Navigation, Collision Detection and Avoidance, and Path Adjustment. The 2D Map-Based Navigation can reduce user's difficulties and improve user's sense of presence and reality in the virtual environments. The experiment study proved that the 2D Map-Based Navigation is a very natural, straightforward and useful navigation interface in the virtual environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.616-619
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• 2002

The z-map structure is widely used for NC tool path verification as it is very simple and fast in calculation of Boolean operations. However, if the number of the x-y grid points in a z-map is increased to enhance its accuracy, the computation time for NC verification increases rapidly. To reduce this computation time, we proposed a NC verification method using 3-D graphic acceleration hardwares. In this method, the z-map of the resultant workpiece machined by a NC program is obtained by rendering tool swept volumes along tool pathos and reading the depth buffer of the graphic card. The experimental results show that this hardware-based method is faster than the conventional software-based method.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.317-318
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• 2006

There are lot of noises and errors in depth map image which is gotten by using a stereo camera. These errors are caused by mismatching of the corresponding points which occur in texture-less region of input images of stereo camera or occlusions. In this paper, we use a method which is able to get rid of the noises through post processing and reduce the errors of disparity values which are caused by the mismatching in the texture-less region of input images through the correlation between the depth map images and the input images. Then we propose a novel method which segments the object by using the improved disparity map images and projections.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2729-2731
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• 2001

In this paper, we studied on the real-time environment map building for the mobile robot navigation using the stereo camera system. Distance measurement are necessary to build the environment map. We used a area-based stereo matching for the distance measurement with the stereo camera system. To reduce the computation time, we used DSP processor on the vision board, took a suitable area size for stereo matching, and used hierarchical search method. Using the fast acquired distance values, the environment map was built.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.1
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• pp.55-61
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• 2017

The V-world, korean type spatial information open platform, provides various services to easily utilize 2D, 3D map and administrative information of the country. Among them, V-world 3D map service, modeled in individual building unit, require requests for each building model file and the draw calls for drawing models on the screen by the request. This causes a large number of model requests and draw calls to occur that increase the latency occurring during the transmission and conversion process between the central processing unit(CPU) and the graphic processing unit(GPU), which lead to the performance degradation of the 3D map service. In this paper, we propose a performance improvement plan to reduce the performance degradation of 3D map service caused by multiple model requests and draw calls. Therefore, we tried to reduce the number of requests and draw calls for the model file by applying a 3D tile model that combined multiple building models to single tile. In addition, we applied the quadtree algorithm to reduce the time required to load the model file by shortening the retrieval time of the model. This is expected to contribute to improving the performance of 3D map service of V-world.

• Toxicological Research
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• v.26 no.1
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• pp.37-46
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• 2010

This study aimed to elucidate anti-inflammatory activities from extracts of Asterina pectinifera on nitric oxide (NO) production, TNF-${\alpha}$ and IL-6 release in lipopolysaccharide (LPS)-stimulated murine macrophage cell, RAW264.7. We prepared the methanolic extracts (60-MAP, 70-MAP, 80-MAP and 90-MAP), aqueous extract (W-AP) and functional bioactive compound fraction (He-AP and EA-AP) from Asterina pectinifera according to extract method. The 60-MAP, 70-MAP, 80-MAP, 90-MAP and W-AP were significantly suppressed LPS-induced production NO, TNF-${\alpha}$ and IL-6 secretion in a concentration-dependent manner (P < 0.05). Especially, 80-MAP by extracted 80% methanol had the strongest activity in reduction of inflammatory mediators among these extracts. Indeed, to identify active fraction, which contained potential bioactive compounds, from 80-MAP of Asterina pectinifera, we tested anti-inflammatory activity of the He-AP or the EA-AP. The He-AP was next extracted from 80-MAP and the EA-AP were extracted from the other methanol layer except the He-AP. The EA-AP demonstrated a strong anti-inflammatory effect through its ability to reduce NO production and it also inhibited the production of proinflammatory cytokines such as IL-6 and TNF-${\alpha}$ at low concentration. These results suggested that the methanolic extract from Asterina pectinifera had the potential inhibitory effects on the production of these inflammatory mediators.