• Journal of the Korea institute for structural maintenance and inspection
• /
• v.10 no.2
• /
• pp.91-101
• /
• 2006

Lately, massive concrete structures are increasingly built. In such massive structures, the heat of hydration of mass concrete causes thermal cracks. To avoid thermal crack, methods widely acceptable for practical use are pre-cooling, pipe cooling and control of placing height. Thermal stress analysis is performed to find the way of controlling the thermal crack of pier footing mat in this paper. The footing mat model for the analysis is $12m{\times}14m$area and 3m height. The analysis results are compared with method of control of lift height and method of pipe cooling. The analysis results show that thermal crack can be removed by method of placing control and pipe cooling at footing mat placed on the ground.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.369-376
• /
• 2001

As many studies have performed to reduce thermal cracking in mass concrete, it is already prepared against thermal cracking, we can find many plans against thermal cracking in several reference book. But it needs practical guidelines to be available in construction site. In this study to establish control method of thermal cracking in mass concrete, tests which have factors of placing thickness and curing method of concrete are performed.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.51 no.12
• /
• pp.571-576
• /
• 2002

This paper is to develop jumping ring system with three sensor arrays and to control levitated ring using dynamic neural mode. Placing an aluminum ring on the core and switching on an AC source causes the ring to jump in the air due to induced currents. The educational system is composed of 40th optical sensor array, encode circuit, 89C51 microprocessor and control board. The control board consists of power IC, and phase controller. Real time process is present to obtain a height of levitated ring for three different sensor arrays. Based on the educational system and the proposed dynamic neural mode, the height of levitation of the ring is controlled by reference signals. This paper focuses on real system controls using the dynamic neural mode with on line learning algorithm.

• Proceedings of the Safety Management and Science Conference
• /
• 2012.04a
• /
• pp.117-137
• /
• 2012

In the ALC(Autoclaved lightweight concrete) manufacturing process, if the pre-cured semi-cake is removed after proper time is passed, it will be hard to retain the moisture and be easily cracked. Therefore, in this research, we took the research by multiple regression analysis to find relationship between variables for the prediction the hardness that is the control standard of the removal time. We study the relationship between Independent variables such as the V/T(Vibration Time), V/T movement, expansion height, curing time, placing temperature, Rising and C/S ratio and the Dependent variables, the hardness by multiple regression analysis. In this study, first, we calculated regression equation by the regression analysis, then we tried phased regression analysis, best subset regression analysis and residual analysis. At last, we could verify curing time, placing temperature, Rising and C/S ratio influence to the hardness by the estimated regression equation.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.04a
• /
• pp.264-269
• /
• 1996

Thermal cracks are occurred when thermal stress due to the hydration of cement exceeds the tensile strength of concrete. In this study, the thermal stresses are investigated at the massive concrete like an anchorage of suspension bridge. The thermal crack can be controlled by considering the placing height, concrete type, pre-cooling and pipe cooling in the design stage.

• Journal of the Korean housing association
• /
• v.17 no.3
• /
• pp.111-121
• /
• 2006

The objective of the study is to derive the quantitative result and method from the solar simulation on the traditional architectonic control methods and their effects for the sunshine on Ddeuljip in Northern Area of Kyongsang-Bukdo Province, Korea. The Ddeuljip(rectangular-shaped housing plan having an inner court) has distinctive form to introduce plentiful sunshine deep inside to the house in spite of disadvantageous condition resulted from the structure of traditional housing composition, that is, Ickrang(linkage block connecting buildings). From the research on the Ddeuljip, following results were derived: First, in the plan the sunshine environment was improved by placing the master bedroom on the right diagonally, or projecting it toward the Ickrang when there isn't enough space for the inner court and the Daechung(wooden floored main hall). Second in the elevation specific sunshine control methods were developed by increasing the height of the master bedroom, reducing the eaves of south elevation, or differentiating the height of ceiling structure gradually.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.1
• /
• pp.133-138
• /
• 2022

In this paper we present the system we produced to help workers at logistic centers and prevent accidents, in which they could get hurt. As a base we use the main control device, named Arduino uno, which measures the weight by using load cells. When operating with the system, by placing object on it, the system measures the weight of the object and keeps the highest point at the same height by lowering its board. This improves the convenience while placing and removing objects from the board. If the weight of the placed object is exceeding the set value the board will also lower itself to secure the safety. By using a line tracer system, the objects are being moved only on a set route with the goal to make it even more comfortable to use.

• International Journal of High-Rise Buildings
• /
• v.3 no.3
• /
• pp.167-171
• /
• 2014

TORANOMON HILLS is the main building of a large-scale re-development project located in the center of Tokyo. This high-rise building has a height of 247 m and 52 floors above ground, 5 floors below ground, and $62m{\times}80m$ in plan. It is used as hotel, residential facilities, offices, shops and conference facilities. The super structure is mainly a rigid steel frame with response-control devices, using concrete-filled steel tube columns. The underground section is a mixed structure composed of steel, steel-reinforced concrete and reinforced concrete framings. The piled-raft foundation type is used. The remarkable feature of this high-rise building is that the motorway runs through the basements of the building, which makes it stand just above the motorway. This condition is an important factor of the building design. The plan shape is designed to fit along the curve of the motorway. Special columns at the corners are required to avoid placing columns in the motorway. This special column is a single inclined column in the lower floors that branches into two columns in the mid-floors to suit the column location in the upper floors. The cast steel joint is used for the branching point of each special column to securely transfer the stress.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.7 no.2
• /
• pp.101-111
• /
• 2012

In the ALC(Autoclaved lightweight concrete) manufacturing process, if the pre-cured semi-cake is removed after proper time is passed, it will be hard to retain the moisture and be easily cracked. Therefore, in this research, we took the research by multiple regression analysis to find relationship between variables for the prediction the hardness that is the control standard of the removal time. We study the relationship between Independent variables such as the V/T(Vibration Time), V/T movement, expansion height, curing time, placing temperature, Rising and C/S ratio and the Dependent variables, the hardness by multiple regression analysis. In this study, first, we calculated regression equation by the regression analysis, then we tried phased regression analysis, best subset regression analysis and residual analysis. At last, we could verify curing time, placing temperature, Rising and C/S ratio influence to the hardness by the estimated regression equation.

• Journal of Sensor Science and Technology
• /
• v.11 no.6
• /
• pp.365-370
• /
• 2002

The jumping ring apparatus described in this study is used to demonstrate and educate the effects of electromagnetic induction. Placing an aluminum ring over the core and switching on AC source causes the ring to jump in the air due to induced currents in the ring producing a magnetic field opposed to that produced in the core. This force is a function of flux density, ac current of ring and levitated height of the ring. Using photo sensor arrays, detect the ring position and represent the position of the ring to analog voltage for an education performance. This paper presents modelling of the jumping ring system and shows how does control signal generate in order to follow desired position.