• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.15-20
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• 2002

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the automatic assembly tasks using hydraulic manipulators. In this manuscript, we applied a compliance control, which is based on the position control by a disturbance observer for our manipulator system. A reference trajectory modification method is proposed in order to achieve accurate force control even though the stiffness and the position of the environment change. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved under various environment conditions. The proposed force control algorithm is applied to the approaching of bolt and the wrenching of nut tasks as one typical task in the maintenance work of live power electric line and is experimentally confirmed very effective for the task.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.568-576
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• 1998

In this thesis discuss with a flexible robotic finger design and controller which is used for the micro flexible robotic finger. So, miniaturization, precision, controller for the control of grasping force and actuator were needed. And, even if we develop a new actuator and controller, in order to use on real system, we must considerate of a many side problem. In a force control of micro flexible finger for grasping an object, the fingertip's vibration was more important task of accuracy control. And, controller were adopt the PD/PI mixed type fuzzy controller. The controller were consist of two part, one is a PD type fuzzy controller for increase the rising time response, the other is a PI type fuzzy controller for decrease of steady-state error. Especially, in a PD type fuzzy controller, we used only seven rules. And, for a PI controller, we adopt a reset factor for the control of input values. so, we have overcome the exceed of controller's input range. For the estimate of ontroller's utility and usefulness, we have experiment and computer simulation of three cases. First, we consider of unit force grasping control for a task object, which is 0.03N. Second, bounding grasping force control which is add to a sinusoidal force on the unit force. At this cases the task force is (0.03+0.01 sin wt N). And consider of following of rectangular forces.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.48-53
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• 1997

The objective of this paper is to present the development and application of interface software between robot and F/T sensor for force control. The interface software for among the robot controller, F/T sensor, and host PC is based on interrupt-driven method. To show the suitability of developed interface software, writing-task is performed in real time using F/T sensor that mounts on the wrist of the robot and Scara type 4-axis robot.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.182-187
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• 2001

This study deals with CARS (Computer Aided ROMUM System) which is a computer version of ROMUM (RObot Modularization of the Unit Motion). ROMUM was a method developed by the concept of modularization of the unit motion of robots. Because CARS is a computer assisted method of menu-driven type for human interface, this method can be easily applied for analyzing the work motion and measuring the execution time of robots. Therefore, it will be helpful for reducing the analysis effort and time of robot work.

• Journal of Internet Computing and Services
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• v.15 no.5
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• pp.9-16
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• 2014

In recent years, the importance of IoT (Internet of Things) is emphasized by information communication technologies and the performance of various smart devices are rapidly developed and applied in the real world. In this paper, we propose a process-driven IoT-object collaboration model to specify and execute a IoT service based on processes. That is, the purpose of this paper is to suggest a formal method in order to describe a IoT service into a group of tasks having execution order and collaboration between IoT-objects in charge of the enactment of a task. Conclusively, through the proposed model, we expect that IoT services will be automatically executed, analyzed, monitored and reused in the process-driven IoT computing environment.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.601-613
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• 2016

The purpose of this study is to present the mental model of young adolescents' media environment and the use and to provide several educational suggestions drawing on the revealed model. For this, the data were collected through 4 activities such as interview, picture drawings, word association experiment, and sentence completion task with ten 4-5th graders in elementary schools; they were qualitatively analyzed by 2 researchers. First, the meaning components driven by sentence completion task, word association experiment were totally 6 components: media device, connection(alienation), competence(provision), entertainment, adverse effects, ambilaterality. Second, the components of media mental model driven by pictures were 4 components: functions/competence, entertainment, conflict with paper books/sharing, harmfulness/ambilaterality. Third, the components from interview consisted of conflict between paper books and electronic media, communication-centeredness, fear(addiction) and users' qualification. Based on those results, careful examination in cyber talk, necessity of addiction prevention, active development of learning media and their balanced utilization with books, and healthful media literacy education and reinforcement of critical thinking were suggested.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.147-153
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• 2007

Task scheduling is an essential part of any computer system for allocating tasks to a processor of the system among various competitors. As we know, in real-time system, the failure of scheduling a hard real-time task my lead to disastrous consequence. Besides efficiency, resource and speed, real-time system has to take time constraint in serious consideration. This paper proposes a priority-driven scheduling algorithm for real-time multiprocessor system. which is called L-RE coordinates algorithm. L-RE coordinates is a new way of describing the task scheduling problem. In the algorithm, we take both deadline and laxity into consideration for allocating the priority. The simulation result shows that the new algorithm is viable and performance better than EDF and LLF algorithm on schedulability and context switch respectively.

• Journal of the Korean Regional Science Association
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• v.39 no.4
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• pp.73-90
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• 2023

This research examines the impact of robotics integration on job dynamics in the U.S. manufacturing sector, adding to the critical dialogue on technological evolution and the future of jobs. Anchored in the task-model framework, the study hypothesizes that robotic integration exerts differential influences on diverse occupational clusters, each identified by their unique task-specific attributes. An in-depth examination was undertaken to elucidate the interplay between robotic integration and the occupation clusters. Employing a multilevel growth curve model, our empirical investigation tracked employment dynamics from 2012 to 2022 across 52 U.S. regions, covering 307 manufacturing occupations. The findings suggest a pronounced job decline within occupations necessitating manual dexterity. Nonetheless, the evidence does not conclusively support that the extent of robotics integration exacerbates this trend. These findings imply that the employment shifts in the U.S. manufacturing sector are predominantly driven by long-standing trends of deindustrialization and functional specialization, rather than by the recent diffusion of robotic technologies.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.12
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• pp.499-506
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• 2019

An intelligent robot should decide its behavior accordingly to the dynamic changes in the environment and user's requirements by evaluating options to choose the best one for the current situation. Many intelligent robot systems that use the Procedural Reasoning System (PRS) accomplishes such task management functions by defining the priority functions in the task model and evaluating the priority functions of the applicable tasks in the current situation. The priority functions, however, are defined locally inside of the plan, which exhibits limitation for the tasks for multi-domain services because global contexts for overall prioritization are hard to be expressed in the local priority functions. Furthermore, since the prioritization functions are not defined as an explicit module, reuse or extension of the them for general context is limited. In order to remove such limitations, we propose a policy-based meta-planning for general task management for multi-domain services, which provides the ability to explicitly define the utility of a task in the meta-planning process and thus the ability to evaluate task priorities for general context combining the modular priority functions. The ontological specification of the model also enhances the scalability of the policy model. In the experiments, adaptive behavior of a robot according to the policy model are confirmed by observing the appropriate tasks are selected in dynamic service environments.

• Smart Structures and Systems
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• v.10 no.4_5
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• pp.331-351
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• 2012

In this study an output-only system identification technique for civil structures under ambient vibrations is carried out, mainly focused on using the Stochastic Subspace Identification (SSI) based algorithms. A newly developed signal processing technique, called Singular Spectrum Analysis (SSA), capable to smooth a noisy signal, is adopted for preprocessing the measurement data. An SSA-based SSI algorithm with the aim of finding accurate and true modal parameters is developed through stabilization diagram which is constructed by plotting the identified system poles with increasing the size of data matrix. First, comparative study between different approaches, with and without using SSA to pre-process the data, on determining the model order and selecting the true system poles is examined in this study through numerical simulation. Finally, application of the proposed system identification task to the real large scale structure: Canton Tower, a benchmark problem for structural health monitoring of high-rise slender structures, using SSA-based SSI algorithm is carried out to extract the dynamic characteristics of the tower from output-only measurements.