Jo Apr 24, 2023
U Yong Nam, a section head at the Robotics Institute, has developed a manned omnidirectional vehicle for carrying books.
Controlled by a librarian, the vehicle moves in narrow corridors between large bookshelves with lots of books to find ordered books and carry them to a conveyor.
The vehicle consists of four omnidirectional wheels, reduction motors, dampers, a control panel, a book basket, a chair, and batteries. The control panel has a monitor, a joystick, and a tablet PC, so the librarian can monitor and control all the states of the vehicle on it.
The four omnidirectional wheels and four DC motors which drive every wheel independently are installed on the vehicle. Each wheel has dampers for safe travel.
The omnidirectional wheels rotate clockwise or counterclockwise according to operation commands and the vehicle moves to a designated position running forward, backward and laterally or turning on the spot.
The vehicle goes in three stages of velocity: 2m/s (first), 1.5m/s (second) and 1m/s (third).
The vehicle is useful in libraries or storehouses with narrow corridors.
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Jo Apr 23, 2023
A research team led by Kim Sung Nam, an institute head at the Faculty of Information Science and Technology, has developed a game program by using cellular automata, which enables study of artificial life.
It is not too much to say that the history of evolution of life is just that of its adaptation to the changing environment. The environment acts on organisms as an input signal. It is hard for them to survive if they fail to receive the signals. Organisms analyse the input of the environment and seek to cope with it.
This artificial life game uses cellular automata to make sure that life moves alive and grows for a long time by changing the life or death rule. This program has an environment for simulation of an artificial life game, and offers diversity of patterns that are generated as the shape and transition rule of 2 dimensional cellular automata are changed.
They have laid a scientific foundation for the realization of a life machine by enabling the game program to give the most concise and persuasive explanation of cellular automata so that people with no professional knowledge of it can understand it.
The program consists of a simulation and application block, a pattern generation block for providing the diversity of patterns by varying the shape of 2-dimensional cellular automata, and a storage and management block for storing and managing the periodic and nonperiodic patterns of a life machine generated by changing environment.
Not only does the program help you to understand the essence of life in the education of artificial life, it can be applied to the sectors of electronics industry and textile engineering.
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Jo Apr 21, 2023
A research group led by Choe Kyong Chol, a lecturer at the Faculty of Materials Science and Technology, has established a casting process of a backing roller for a cement kiln on the basis of an effect analysis of factors on the quality of large steel castings.
For its design, two things should be taken into consideration ― it is a large and massive steel casting (tens of tonnes) and its thick walls could cause mass effect.
Therefore, what is important for the establishment of casting processes is proper design of casting plans, design of inner chill, selection of molding material and inoculation of molten metal.
They considered the contraction amount as 1.8% according to the chemical composition of a backing roller to calculate the gating system and they used ProCAST2016 to simulate the flow and solidification of molten metal to design a proper casting plan.
Both riser and chill were used at the same time to ensure directional solidification due to the great height of castings.
The weight of inner chill was set to be 2% of pouring weight of casting and its dimensionφ20mm in diameter.
Rahung silica sand was used as molding material (about 5mm in diameter). The coating was made by magnesia clinker (about 2mm in thickness).
Boron, titanium and rare earths were added to the molten metal to raise the quality of a backing roller and to reduce mass effect.
The backing roller has a tensile strength of over 550 MPa, an elongation of 12% and a hardness of about HB180.
This casting process can be used for manufacturing massive large steel castings.
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Jo Apr 20, 2023
Pak Song Chol, a researcher at the Faculty of Physical Engineering, has determined agitation factors of reactants for coal liquefaction, set up an experimental process, and studied their effects on the treatment through an experiment.
It is the mixing ratio in COWM(coal-oil-water mixture) production for liquefaction that should provide an environment for coal powder particles bonding into crude oil molecules and allow enough electric current for HVHF discharge. Here, the bonding environement depends on the ratio of oil while discharge current depends on the ratio of water.
At the begining, coal:oil:water =5:1:4 in w.t. ratio was adopted. However, self-oganization of coal powder particles needed higher ratio of oil so that different mixing experiments were conducted with different factors. As a result, it was concluded that coal:oil:water =1:(1~2):(0.5~1) in w.t. ratio is more effective for self-organization of coal powder particles of the mixture in post-reaction, as well as during discharge accompanied by continuous flow.
The experiments were conducted both in static and dynamic manners. The static experiment was for estimation of yield while the dynamic one was for quality assessment in addition to yield with different raw materials.
The measured factors and results showed that the diesel oil distilled out of the products in his ratio is as good as commercial diesel oil in terms of moisture content, ash content, sulfur content, aqui-soluble acid-alkali.
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Jo Apr 18, 2023
Sin Tong Jun, a researcher at the Faculty of Information Science and Technology, developed a tactic supporting system for small size robot soccer.
The robot soccer tactics simulation system covers formation design, strategic positioning of players, a situation-based intentional cooperative attacking tactic, an aid-obligatory array-based dynamic cooperative defending method and a genetic-reinforcement learning-based online tactics learning method.
In the formation design, you can set initial positions and movement ranges of each player in formations like 4-3-3, 4-4-2 and 4-2-4. For dynamic transformation of formations, you can select any formation table when necessary.
In the strategic positioning, the positioning of team players without a ball is modeled for 40-metre stonewall defense, which supports all-out attack and all-in defense and the numerical superiority of the team around the ball at the same time.
In the situation-based intentional cooperative attacking tactic, preconditions and stoppage conditions for passing a ball among players in such situations with high stochastic presence as a kick-off or a corner kick are designed so that intentional cooperative attacks among players can be made.
In aid-obligatory array-based dynamic cooperative defense tactic, an assistant player is selected when it is impossible for a single player to change the current situation so as to support unified cooperation among players, and problems of task sharing among players are solved to ensure dynamic defense.
The genetic-reinforcement learning-based online tactic learning is divided into tactic rule generation and tactic selection control. In tactic selection control, you control parameters for kicking, dribbling and passing. In tactic rule generation, determination of attacking and defensive situations, determination of the main robot and an assistant robot, and determination of ball handling of the main robot and the movement point of the assistant robot are completed by genetic-reinforcement learning so that tactic rules for a goal can be found automatically.
Formation designing and strategic positioning can increase shooting success rate by 12%. Intentional cooperative attacking tactic and dynamic cooperative defense tactic can improve the average attacking rate by more than 3% and the average ball possession rate by more than 10%. Genetic-reinforcement learning helps to find a new team tactic against opponents within 1000ms after the kick-off of the first half.
The system is available for small size Robot League and for control of intelligent robots working for automated factories. It also finds use in the measurement and assessment of techniques newly arising in the distributed AI field.
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Jo Apr 17, 2023
Hong Phyong Il, a section head at the Faculty of Applied Mathematics, has provided a new condition for the existence of fixed points of contractive mapping which maps a non-set into a compact subset on a b-metric space, and on this basis, he has introduced a condition for the existence of fixed points of contractive mapping on a complete b-metric space.
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