• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.9
• /
• pp.4529-4548
• /
• 2016

DDoS attacks have had a devastating effect on the Internet, which can cause millions of dollars of damage within hours or even minutes. In this paper we propose a practical dynamic defense approach that overcomes the shortage of static defense mechanisms. Our approach employs a group of SDN-based proxy switches to relay data flow between users and servers. By substituting backup proxy switches for attacked ones and reassigning suspect users onto the new proxy switches, innocent users are isolated and saved from malicious attackers through a sequence of remapping process. In order to improve the speed of attacker segregation, we have designed and implemented an efficient greedy algorithm which has been demonstrated to have little influence on legitimate traffic. Simulations, which were then performed with the open source controller Ryu, show that our approach is effective in alleviating DDoS attacks and quarantining the attackers by numerable remapping process. The simulations also demonstrate that our dynamic defense imposes little effect on legitimate users, and the overhead introduced by remapping procedure is acceptable.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.1
• /
• pp.43-50
• /
• 2014

This paper introduces a robot platform which can do weeding while traveling between rice seedlings stably against irregular land surface of a paddy field. Also, an autonomous navigation technique that can track on stable state without any damage of the seedlings in the working area is proposed. Detection of the rice seedlings and avoidance knocking down by the robot platform is achieved by the sensor fusion of a laser range finder (LRF) and an inertial measurement unit (IMU). These sensors are also used to control navigating direction of the robot to keep going along the column of rice seedling consistently. Deviation of the robot direction from the rice column that is sensed by the LRF is fed back to a proportional and derivative controller to obtain stable adjustment of navigating direction and get proper returning speed of the robot to the rice column.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.3
• /
• pp.25-30
• /
• 2014

This paper describes the design of gate driver circuits in distributed maximum power point tracking(DMPPT) controller for photovoltaic system. For the effective DMPPT control in the existence of shadowed modules, high voltage gate driver is applied to drive the DC-DC converter in each module. Some analog blocks such as 12-b ADC, PLL, and gate driver are integrated in the SoC for DMPPT. To reduce the power consumption and to avoid the high voltage damage, a short pulse generator is added in the high side level shifter. The circuit was implemented with BCDMOS 0.35um technology and can support the maximum current of 2A and the maximum voltage of 50V.

• Journal of Biosystems Engineering
• /
• v.37 no.3
• /
• pp.201-208
• /
• 2012

Purpose: This study was conducted to develop a vegetable transplanting robot which transplants seedlings from a nursery tray to a plant pot using its four fingers. Method: The robot consists of the transplanting part, nursery tray moving part, plant pot moving part, main frame and controller. Two moving parts are controlled by the photo sensor and servo motor. The transplanting part was composed with two components; transporting device using E-MY2H(SMC Corp., Japan) for controlling finger position accurately and finger for transplanting the seedling. Results: Head lettuce using the transplanting robot was transplanted in 21 days after sowing based upon the seed shape measurement and removing examination. The optimal finger shape was thin pin type because it caused minimum damage to the roots of seedlings. Conclusions: The four inclined pin type was applied to remove the seedlings from the nursery tray. In addition, the transplanting capacity of the developed robot was 2800 pots per hour and the rate of success was 99% and above.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2289-2291
• /
• 2002

In maned airport, crews may have risks as they manage passenger control system in IPMS in damage situations such as fire in a airport. So the application of unmanned autonomous system can reduce the number of boarding crews and attribute to safe airplane transportation. PBBC model can be used to obtain control strategy, and airplane and enhance operators' skill by simulating the airport. The paper suggests an intelligent system of the pbbc control using microprocessor in integrated platform management system which can take measures against passenger situation of a airplane excluding unnecessary warnings with undamaged situations. The system here detected the passenger more accurately and adopted more appriate measures according to airplane status compared with conventional systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.489-491
• /
• 2013

In this paper, Electronic Drum based on Arduino and Processing language to communicate with a computer is implemented. First, we made a drum pad by using piezoelectric sensors. The drum pads prevent damage to the sensor and new mechanism was fabricated to mitigate the impact structure. Arduino connected to the pad, the sensor detects a signal when the shock sends it to Arduino. The received signal of Arduino sends a signal to the computer, and the signal received is stored in the computer to output sound of the drum. Through this structure, the micro-controller, the computer and communications technology can be combined and applicable to a many system.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.1
• /
• pp.11-16
• /
• 2020

In this paper, system that includes multiple unmanned aerial vehicles (UAVs) are considered. The vehicles are equipped with a mission computer for a specific mission and equipment. The mission equipment operates based on the time of mission computer. Also, data collected by flight computer and mission computer is saved with the time of each operating system. Generally, time offset between multiple computers always exists, though the computers are connected to the Internet. When the data collected by multiple computers is combined, the time offset causes damage on reliability of the combined data. Computers that connected to the Internet are synchronized by network time protocol (NTP). This paper proposes a system that the time of multiple mission computers are synchronized by the same NTP server to minimize the time offset. In the results of the measurement, the system time offset of multiple mission computer is maintained within 10ms from the system time of the server computer.

• Proceedings of the KIEE Conference
• /
• 2005.10a
• /
• pp.139-144
• /
• 2005

In this paper, We are going to propose the fire protection system with using CAN(Controller Area Network). The larger, higher and deeper buildings are, the more dangerous people are when fire happens. We should be aware of the problems of prior fire protection system. Therefore, we construct embedded system based on CAN communication that is capable of N:N communication, and build independent fire protection system. If the fire is occurred on the building, the problem is that how fast we can detect the fire and put off it by using available system, this is major factor that reduces damage of our wealth, therefore in this studies We would like to design more stable system than current system. this system that is based on CAN communication which is available N:N communication constructs and is designed to compensate for each fault so that our aim is to reduce the line of system and cost of installation and to suppose future type fire protection system. We are simulated by NIST FDS(Fire Dynamics Simulator) to prove the efficiency of this system.

• Annual Conference of KIPS
• /
• 2002.04b
• /
• pp.1203-1206
• /
• 2002

In maned airport, crews may have risks as they manage passenger control system in IPMS in damage situations such as fire in a airport. So the application of unmanned autonomous system can reduce the number of boarding crews and attribute to safe airplane tranportation. PBBC model can be used to obtain control strategy, and airplane and enhance oprators' skill by simulating the airport. The paper suggests an intelligent system of the pbbc control using microprocessor in integrated platform management system which can take measures against passenger situation of a airplane excluding unnecessary warnings with undamaged situations. The system here detected the passenger more accurately and adopted more appriate measures according to airplane status compared with conventional systems.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.2
• /
• pp.227-233
• /
• 2019

In recent years, vehicle fires account for the second highest rate after residential fires. It accounts for more than 10.7% of the total fire occurrence rate. Vehicle fires are very difficult to evolve at an early stage. Most of the vehicles are burned down in the event of a fire, resulting in a lot of physical and personal damage. In the EU and other countries, efforts are being made to install automatic fire extinguishing systems in preparation for vehicle fires. In addition, since the automatic fire extinguishing system applied to a vehicle must operate in a moving state of a car, a method for detecting a fire is needed. Therefore, this paper proposes a structure of an automatic fire extinguishing system that can evolve a fire when a fire occurs in a commercial vehicle among various vehicles. Especially, it confirms the feasibility of the automatic fire extinguishing system simulated in the laboratory environment and confirms its applicability.