• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.26-34
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• 2008

The information of traversability and path planning is essential for UGV(Unmanned Ground Vehicle) navigation. Such information can be obtained by analyzing 3D terrain. In this paper, we present the method of 3D terrain modeling with color information from a camera, precise distance information from a 2D Laser Range Finder(LRF) and wheel encoder information from mobile robot with less data. And also we present the method of 3B terrain modeling with the information from GPS/IMU and 2D LRF with less data. To fuse the color information from camera and distance information from 2D LRF, we obtain extrinsic parameters between a camera and LRF using planar pattern. We set up such a fused system on a mobile robot and make an experiment on indoor environment. And we make an experiment on outdoor environment to reconstruction 3D terrain with 2D LRF and GPS/IMU(Inertial Measurement Unit). The obtained 3D terrain model is based on points and requires large amount of data. To reduce the amount of data, we use cubic grid-based model instead of point-based model.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.271-278
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• 2014

In spite of that stop line and crosswalk should be aware of the most basic objects in transportation system, its features extracted are very limited. In addition to image-based recognition technology, laser and RF, GPS/INS recognition technology, it is difficult to recognize. For this reason, the limited research in this area has been done. In this paper, the algorithm to recognize the stop line and crosswalk is designed and implemented using image-based recognition technology with the images input through a vision sensor. This algorithm consists of three functions.; One is to select the area, in advance, needed for feature extraction in order to speed up the data processing, 'Region of Interest', another is to process the images only that white color is detected more than a certain proportion in order to remove the unnecessary operation, 'Color Pattern Inspection', the other is 'Feature Extraction and Recognition', which is to extract the edge features and compare this to the previously-modeled one to identify the stop line and crosswalk. For this, especially by using case based feature comparison algorithm, it can identify either both stop line and crosswalk exist or just one exists. Also the proposed algorithm is to develop existing researches by comparing and analysing effect of in-vehicle camera installation and changes in recognition rate of distance estimation and various constraints such as backlight and shadow.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.789-796
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• 2016

In the Core Technology R&D of the defence area, the development of the related core element technology could be the foundation to develop advanced weapon system in the future. But it might make various problems if you can not accurately define the TRL of the element technology. In other words, if the technology is not sufficiently mature and then the project starts, it might require an increase in the development period and additional cost. Finally the system will be in an incomplete state and result in user dissatisfaction and the project failure. Therefore it is a very important task to properly assess the TRL for a successful project. In this study, We propose the method for risk management of core technology R&D project of the defence area using the QFD process with degree of difficulty and technology readiness level. It is also presented the process to determine the risk level using TRL and Degree of difficulty. Finally We apply this method to UGV system for verifying the result of this study.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.35-41
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• 2008

The most important requirement for the automotive radars is the simultaneous target range and velocity measurement under environment of multi-target, clutters, multi-path, and so on. If the many vehicles with 77GHz FMCW(Frequency Modulation Continuous Wave) radar system are in the near area we should consider the interference signals occurred by other radar systems because these signals reduce exact detection of range and velocity. In this paper, we propose the interference cancellation method, which each vehicle radar transmits chirp trains with the different frequency sweep shapes. The proposed method is applied into the various applications such as an intelligent vehicle, Robot, and UGV(Unmanned Ground Vehicle).

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.843-850
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• 2011

In this paper, an effective path generation algorithm for obstacle avoidance producing small amount of steering action as possible is proposed. The proposed path generation algorithm can reduce unnecessary steering because of the small lateral changes in generated waypoints when UGV (Unmanned Ground Vehicle) encounters obstacles during its waypoint navigation. To verify this, the proposed algorithm and $A^*$ algorithm are analyzed through the simulation. The proposed algorithm shows good performance in terms of lateral changes in the generated waypoint, steering changes of the vehicle while driving and execution speed of the algorithm. Especially, due to the fast execution speed of the algorithm, the obstacles that encounter suddenly in front of the vehicle within short range can be avoided. This algorithm consider the waypoint navigation only. Therefore, in certain situations, the algorithm may generate the wrong path. In this case, a general path generation algorithm like $A^*$ is used instead. However, these special cases happen very rare during the vehicle waypoint navigation, so the proposed algorithm can be applied to most of the waypoint navigation for the unmanned ground vehicle.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.453-464
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• 2012

This is a research of an adaptive longitudinal control system for situated cognition in wide range, traffic accidents reduction and safety driving environment by integrated system which graft a road infrastructure's information based on IT onto the intelligent vehicle combined automobile and IT technology. The road infrastructure installed by laser scanner in intersection, speed limited area and sharp curve area where is many risk of traffic accident. The road infra conducts objects recognition, segmentation, and tracking for determining dangerous situation and communicates real-time information by Ethernet with vehicle. Also, the data which transmitted from infrastructure supports safety driving by integrated with laser scanner's data on vehicle bumper.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.73-79
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• 2010

A preliminary study on a length-variable rotor blade for a small unmanned helicopter has been conducted. After surveys on previous researches, and examining requirements for application to a small unmanned helicopter, a length-variable rotor blade was designed and manufactured to be driven by centrifugal force from rotor revolution with no mechanical actuator. The rotor blade was divided into a fixed inboard section and an outboard section sliding in span-wise direction. In order to determine the operating conditions of the length-variable rotor during revolution, and to derive the design variables of extension spring and rotor weight, a series of analyses from multi-body dynamics solution were conducted. The manufactured prototype was verified of its length-varying mechanism from a rotor stand, the results and required future improvements are discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.873-880
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• 2008

This paper deals with the peer-to-peer data communication to connect each distributed levels of developed unmanned system according to the JAUS. The JAUS is to support the acquisition of unmanned system by providing a mechanism for reducing system life-cycle costs. Each of distributed levels of the JAUS protocol divides into a system, some of subsystems, nodes and components/instances, each of which may be independent or interdependence. We have to distribute each of the levels because high performance is supported in order to create several sub-processor computing data in one processor with high CPU speed performance. To complement such disadvantage, we must think the concept that a distributed processing agrees with separating each of levels from the JAUS protocol. Therefore, each of distributed independent levels send data to another level and then it has to be able to process the received data in other levels. So, peer-to-peer communication has to control a data flow of distributed levels. In this research, we explain each of levels of the JAUS and peer-to-peer communication structure among the levels using our developed unmanned ground vehicle.

• Journal of Applied Reliability
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• v.17 no.2
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• pp.168-180
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• 2017

Purpose: In this research, we develop an effectiveness analysis simulation model using Agent Based Modeling with Communication Effects for the development of a new weapon system. Methods: To describe the future battlefield that has more complexity, we develop Agent Based Modeling to describe communication Effects. We use the communication theory (Path-Loss Model) and the real map. Results: We have compared simulation model with real map and simulation model without real map. The Blue Survival Ratio of simulation model with real map is worse than one without real map since the performance of communication gets lower. Conclusion: There are many studies about the effectiveness analysis of a weapon system. Most of previous researches assumed no communication error. In the real world, however, it's not appropriate assumption. Therefore, this study considers the communication error and shows that it is important factor in the effectiveness analysis.

• International Journal of High-Rise Buildings
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• v.11 no.2
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• pp.115-124
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• 2022

Welding is a significant part of the construction industry. Since most high-rise building construction structures rely on a robust metal frame welded together, welding defect can damage welded structures and is critical to safety and quality. Despite its importance and heavy usage in construction, the labor shortage of welders has been a continuous challenge to the construction industry. To deal with the labor shortage, the ultimate goal of this study is to design and develop an automated robotic welding system composed of a welding machine, unmanned ground vehicle (UGV), robotic arm, and visual sensors. This paper proposes and focuses on automated weaving using the robotic arm. For automated welding operation, a microcontroller is used to control the switch and is added to a welding torch by physically modifying the hardware. Varying weave patterns are mathematically programmed. The automated weaving is tested using a brush pen and a ballpoint pen to clearly see the patterns and detect any changes in vertical forces by the arm during weaving. The results show that the weave patterns have sufficiently high consistency and precision to be used in the actual welding. Lastly, actual welding was performed, and the results are presented.