• IEMEK Journal of Embedded Systems and Applications
• /
• v.15 no.3
• /
• pp.149-157
• /
• 2020

Regarding previously-developed drone simulators, it was easy to check their flight stability or controlling functions based on the condition that their weight was fixed from the design. However, the drone is largely classified into two types that is the one with the fixed weight whose purpose is recording video with camera and racing and another is whole weight-variable during flight with loading the articles for delivery and spraying pesticide though the weight of airframe is fixed. The purpose of this thesis is to analyze the structure of drone and its flight principle, suggest dynamics-model-based simulator that is capable of simulating weight-variable drone and develop the simulator that can be used for designing main control board, motor and transmission along the application of weight-variable drone. Weight-variable simulator was developed by using various calculation to apply flying method of drone to the simulator. First, ground coordinate system and airframe-fixing coordinate system were established and switching matrix of those two coordinates were made. Then, dynamics model of drone was established using the law of Newton and moment balance principle. Dynamics model was established in Simulink platform and simulation experiment was carried out by changing the weight of drone. In order to evaluate the validity of developed weight-variable simulator, it was compared to the results of clean flight public simulator against existing weight-fixed drone. Lastly, simulation test was performed with the developed weight-variable simulation by changing the weight of drone. It was found out that dynamics model controlled various flying positions of drone well from simulation and the possibility of securing the optimum condition of weight-variable drone that has flying stability and easiness of controlling.

• Journal of Animal Environmental Science
• /
• v.5 no.2
• /
• pp.93-100
• /
• 1999

Pig's original image data was transformed to a binary image, an image excluding head and tail portion from the whole binary image, and a projected image associated with pig's height. Then the length of body, width of shoulder, and area of pig were calculated and the relationships among the above characteristics and pig's weight were analyzed. The results obtained from this study were as follows: 1. Whole binary image data was considered to be improper to determine the pig's weight because the movement of pig's head and tail portion affected the image data. 2. Binary image data excluding head and tail portion from the whole binary image showed a better estimation of the pig's weight than the whole binary image. 3. Pig's should width was analyzed to be improper factor to determine the pig's weight. 4. The projected image associated with pig's height showed the highest correlation between the pig's area of the image and pig's weight(R2=0.9965). From this research the projected image associated with pig's height, which is excluding head and tail portion from the whole body of pig's image, was considered to be the prime factor to measure the pig's weight by the noncontact measurement.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.59 no.3
• /
• pp.215-220
• /
• 2023

This study developed and evaluated a load cell-based automatic weighing system for the automated harvesting of laver (Porphyra tenera) in seaweed aquaculture. The current manual harvesting process was compared with the load cell-based automated system, and quantitative measurements of time, distance, and weight were conducted. The results demonstrated that the load cell-based system reduced the unloading time and increased the throughput compared to the manual method. In addition, statistical analysis confirmed that there was no significant difference from the mean in the weight measurement obtained using the load cell-based system. Based on these findings, the load cell-based automatic weighing system holds potential for efficient production and transactions in laver cultivation, contributing to cost reduction and improving the quality of life for aquaculture workers.

• Tribology and Lubricants
• /
• v.16 no.6
• /
• pp.461-468
• /
• 2000

In this study, a neural network based diagnostic system of a rotating spindle system supported by ball bearings was introduced. In order to create actual failure situations, two exemplary abnormal status were made. Out of several possible data source locations, ten measurement spots were chosen. In order to discriminate multiple abnormal status, a neural network system was introduced using back propagation algorithm updating connecting weight between each nodes. In order to find the optimal structure of the neural network system reducing the information sources, magnitude of the weight of the network was referred. Hinton diagram was used to visually inspect the least sensitive weight connecting between input and hidden layers. Number of input node was reduced from 10 to 7 and prediction rate was increased to 100%.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.3
• /
• pp.124-130
• /
• 2003

Many structural evaluation procedures of road and airfield pavements use the Falling Weight Deflectometer (FWD) as a critical element of non-destructive deflection testing. FWD is a trailer mounted device that provides accurate data on pavement response to dynamic wheel loads. A dynamic load is generated by dropping a mass from a variable height onto a loading plate. The magnitude of the load and the pavement deflection are measured by a load celt and geophones. And database concerning pavement damage should be enhanced to analyze loss of thickness asphalt layer caused from the plastic deformation of pavement structure, such as cracking or rutting. The prototype FWD is developed, which consists of chassis system, hydraulic loading system, data acquisition and analysis system. This system subsequently merged to from automation management system and is then validated and updated to produce a working FWD which can actually be used in the field.

• Structural Engineering and Mechanics
• /
• v.70 no.1
• /
• pp.81-96
• /
• 2019

In this paper, a hybrid uncertain model is applied to system reliability based design optimization (RBDO) of trusses. All random variables are described by random distributions but some key distribution parameters of them which lack information are defined by variation intervals. For system RBDO of trusses, the first order reliability method, as well as monotonicity analysis and the branch and bound method, are utilized to determine the system failure probability; and Improved (${\mu}+{\lambda}$) constrained differential evolution (ICDE) is employed for the optimization process. System reliability assessment of several numerical examples and system RBDO of different truss structures are proposed to verify our results. Moreover, the effect of different classes of interval distribution parameters on the optimum weight of the structure and the reliability index are also investigated. The results indicate that the weight of the structure is increased by increasing the uncertainty level. Moreover, it is shown that for a certain random variable, the optimum weight is more increased by the translation interval parameters than the rotation ones.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.9
• /
• pp.761-768
• /
• 2016

Weight bearing is effective during rehabilitation of gait, in the elderly and disabled people. Various training devices using weight bearing function were developed along with treadmill walking; however, no device has been developed in conjunction to walking on the ground. Here, we designed a rail type frame of a gait rehabilitation system for body-weight support (BWS) function, and analyzed its mechanical safety in the static weight bearing condition of a vertical axis. Computational simulations were performed to analyze structure of the driving parts, which are connected with a rail and driving rollers and the lower plate of the BWS. Structural analyses showed the drivers and BWS were safe, when simulated at 135kg weight under static conditions. Thus, this rail type rehabilitation system can be used for gait training of the elderly and disabled.

• Journal of Ocean Engineering and Technology
• /
• v.27 no.6
• /
• pp.22-26
• /
• 2013

The purpose of this study was to improve the design of a mooring line by attaching a lumped mass to it on the seabed. A numerical analysis of the redesigned mooring system is performed to analyze the effect of the weight of the attached lumped mass using the commercial software Orcaflex. The ultimate tension of the mooring system with the lumped mass is compared with that of a bare mooring line in the original design. An appropriately designed weight for the lumped mass is found to induce a critical lifted point in the mooring line by floater motion in the ultimate condition to move toward the floater position from the anchor point, while maintaining a similar safety factor for the mooring line. On the other hand, it is shown that excess weight for the lumped mass induces snapping in a mooring line, resulting in low safety factor for the mooring system. The distance between lumped weights is shown to be a minor parameter affecting the safety of a mooring line, although a shorter line has an advantage from an economic point of view. Using the optimal weight for the lumped mass attached to the mooring line on a seabed reduces the mooring line length and installation area occupied by a mooring system under real sea conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.8
• /
• pp.1585-1590
• /
• 2002

This paper reports on the balance weight effect on the lubrication and friction characteristics of crankshaft system. To determine the main bearing loads, the crankshaft was treated as statically determinate system. Four and eight-balance weight crankshafts were considered, and minimum oil film thickness and friction loss were calculated. The main bearing loads were increased in the four-balance shaft due to the increasing of unbalanced rotating mass at No. 1 and 3 main bearing sides. The minimum oil film thickness of four-balance shaft became thinner than eight-balance, and friction loss was increased.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.05a
• /
• pp.214-215
• /
• 2014

Technologies on energy saving and materials used in curtain walls have progressed with increase of high-rise and large buildings. This study is explain fire resistance performance of the curtain walls. And focused on bond strength of light-weight inorganic ceramic board in high temperature for fire resistant curtain-wall system. From the result, curtain-wall system high fire resistant using the light-weight inorganic ceramic board.