• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1480-1484
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• 2004

In this paper, a self-propulsive and small concrete floor finishing trowel robot with twin trowels is proposed. Due to the small size and omni-directional moving capability, it is adequate for small space such as apartment. By adjusting the posture of trowels, it can move in any direction without wheels. We used cheap PIC processor for the cost saving design of the modules and adopted mode processors for easy operation of control stick. For the position control of the robot, we made a motion control algorithm appealing to the stepping motor driver module and the wireless communication module between the robot and PC (or control stick). In this paper, we discuss the control problem of the floor finishing robot in order to move to the right position. By comparing experimental result with simulation, we show the validity of the robot mechanism, sensors, and the control system.

• Journal of Periodontal and Implant Science
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• v.41 no.1
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• pp.44-50
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• 2011

Purpose: Pathologic tooth migration (PTM) is a tooth displacement which is derived from imbalance of tooth retention force and is dominantly found out in maxillary anterior area. PTM in maxillary anterior area was tried to corrected with periodontal treatment and a clear aligner in this study and the result was evaluated clinically and radiographically. Methods: For the treatment of a patient with chronic periodontal disease accompanied by maxillary anterior pathologic tooth migration, clear aligner was applied to move teeth after a series of case-related periodontal therapy. Clinically, probing depth, gingival recession, clinical attachment level and mobility were measured pre- and post-treatment, and radiographic examination was performed as well. Results: Clinically, we found the decrease of the probing depth, gingival recession, clinical attachment level and mobility. And we could also acknowledge the reduction of vertical and horizontal dimension on infrabony defect radiographically. However, it is still controversial if there was an actual bone filling. Conclusions: Clear aligner is an effective appliance to move teeth since it costs little in terms of expense and time. In addition, it wraps whole crowns, providing advantages to deal with crowding, spacing, and size of arch. In short, clear aligner could be a useful treatment option for PTM patient, since it provides decreased probing depth, gingival recession, clinical attachment level, mobility and esthetical restoration.

• Journal of Sensor Science and Technology
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• v.14 no.6
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• pp.409-414
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• 2005

For an intelligent vehicle driving which uses magnetic markers and magnetic sensors, we can get every kind of road information while moving the vehicle if we use the code that is encoded with N, S pole direction of markers. If we make it an only aim to move the vehicle, it becomes easy to control the vehicle the more we put markers close. By the way, to recognize the direction of a marker pole it is much better that the markers have no effect each other. To get road informations and move the vehicle autonomously we propose the methods of arranging magnetic sensors and algorithm of recognizing the position of the vehicle with those sensors. We verified the effectiveness of the methods with computer simulation.

• Journal of Power Electronics
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• v.16 no.2
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• pp.798-804
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• 2016

This paper proposes a new operation and control strategy for Power-Assisted Wheelchairs (PAW) using one brushless DC (BLDC) motor. The conventional electrical wheelchairs are too heavy and large for one person to move because they have two electric motor wheels. On the other hand, the proposed PAW system has a small volume and is easy to move due to the presence of a single wheel motor. Unlike the conventional electric wheelchairs, this structure for a PAW does not have a control joystick to reduce its weight and volume. To control the wheelchair without a joystick, a special control system and algorithm are needed for proper operation of the wheelchair. In the proposed PAW system uses only one sensor to detect the acceleration and direction of PAW's movement. By using this sensor, speed control can be achieved. With a speed control system, there are three kinds of operations that can be done on the speed of a PAW: the increment of PAW speed by summing external force, the decrement of PAW speed by subtracting external force, and emergency breaking by evaluating the time duration of external force. The validity of the proposed algorithm is verified through experimental results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5442-5463
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• 2016

Designing efficient routing protocols for a wireless sensor network with mobile sinks (mWSN) is a challenging task since the network topology and data paths change frequently as sink nodes move. In this paper, we design a novel lightweight reactive ring based routing protocol called R3, which removes the need of proactively maintaining data paths to mobile sinks as they move in the network. To achieve high packet delivery ratio and low transmission cost, R3 combines ring based forwarding and trail based forwarding together. To support efficient ring based forwarding, we build a ring based structure for a network in a way such that each node in the network can easily obtain its ring ID and virtual angle information. For this purpose, we artificially create a virtual hole in the central area of the network and accordingly find a shortest cycled path enclosing the hole, which serves as base ring and is used for generating the remaining ring based structure. We accordingly present the detailed design description for R3, which only requires each node to keep very limited routing information. We derive the communication overhead by ring based forwarding. Extensive simulation results show that R3 can achieve high routing performance as compared with existing work.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.183-185
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• 1994

A new method for determination of electric parameter of cell membranes is proposed. Two circular electrodes is designed to have repulsive force. From the potential energy analysis, stable points where a cell is levitated between electrodes exist and move as frequency or voltage change. The levitated cell in the stable point fall freely when DEP force is zero. The DEP force is dependent on the frequency and the force is zero at the critical frequency. The critical frequency is determined by measuring the difference between the time taken at zero-applied voltage and the time taken at the frequency and the voltage. For example, the critical frequency and stable points of N.crassa slime cell is numerically evaluated. In the exeriment, polystyrene in water is levitated at the stable point. We show that the stable point move as the applied voltage is changed.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.5
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• pp.635-642
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• 2012

The Packet radio C2OTM(Command and Control On The Move) for Command, Control and situational awareness in communication environment of current Combat Net Radio Network is required in a relay transmission techniques. This is to assure the reliability of information transfer, and extend Wireless Coverage and overcome Communication obstacles of mountainous terrain. For the reliability of information transmission in tactical environment, Ad hoc Networking is necessary considering communication environment and an appropriate application of error correction. In this study, We propose a on-demand SDR algorithm that is currently being applied the FEC, Golay, Repetition Code. This enhanced relay transfer uses Ack Reply in tactical operating environment of MIL-STD-188-220 Protocol.

• The Journal of Natural Sciences
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• v.12 no.1
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• pp.1-9
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• 2002

Let G be a connected graph on n vertices. The pebbling number of graph G, f(G), is the least m such that, however m pebbles are placed on the vertices of G, we can move a pebble to any vertex by a sequence of moves, each move taking two pebbles off one vertex and placing one on an adjacent vertex. In this paper, we compute the pebbling number of the Petersen Graph. We also show that the pebbling number of the categorical Product G.H is (m+n)h where G is the complete bipartite graph $K_{m,n}$ and H is the complete graph with $h(\geq4)$ vertices.

• Journal of Educational Research in Mathematics
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• v.25 no.1
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• pp.95-111
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• 2015

The purpose of this study is to analyze cases on teaching solutions exploration of Wythoff's game through using the analogy for the gifted elementary students, to suggest useful teaching methods. Students recognized structural similarity among problems on the basis of relevance of conditions of problems. The discovery of structural similarity improves the ability to solve problems. Although 2 groups-NIM game with surface similarity is not helpful in solving Wythoff's game, Queen's move game with structural similarity makes it easier for students to solve Wythoff's game. Useful teaching methods to find solutions of Wythoff's game through using the analogy are as follow. Encoding process helps students make sense of the game. It is significant to help students realize how many stones are remained and how the location of Queen can be expressed by the ordered pair. Inferring process helps students find a solution of 2 groups-NIM game and Queen's move game. It is necessary to find a winning strategy through reversely solving method. Mapping process helps students discover surface similarity and structural similarity through identifying commonalities between the two games. It is crucial to recognize the relationship among the two games based on the teaching in the Encoding process. Application process encourages students to find a solution of Wythoff's game. It is more important to find a solution by using the structural similarity of the Queen's move game rather than reversely solving method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.440-447
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• 2018

Double parking is very common in a parking lot where there is not sufficient parking space. When we double-park a car, we leave transmission gear in neutral position and release the emergency brake so that the double-parked car can be moved just by pushing it. However, moving a double-parked car by pushing is very hard and dangerous especially for the old and the weak. So, we propose an omni-directional mobile robot for moving a double-parked car easily and safely. The developed omni-directional mobile robot moves a double-parked car by rotating a wheel of a double-parked car. It has two specially designed rollers to rotate a wheel of a double-parked car and is designed so that the height of the robot is very low to be able to enter beneath a double-parked car. It can move a double-parked car safely by detecting obstacles in the way with five ultrasonic sensors. We verified by several experiments that the developed omni-directional mobile robot can be used to move a double-parked car easily and safely.