• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.147-153
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• 2004

This paper presents an analytical modeling technique fer representing a hysteretic behavior of a multi-leaf spring used for a large truck. It divides a nonlinear hysteretic curve of the multi-leaf spring into four parts; loading part, unloading part and two transition parts. It provides conditions fur branching to a part of the curve corresponding to a current multi-leaf spring status. This paper also presents a computational modeling technique of the multi-leaf spring. It models the multi-leaf spring with three links and a shackle. It assumes those components as rigid bodies. The links are connected by rotational joints, and have rotational springs at the joints. The spring constants of the rotational springs are computed with a force from the analytical model of the hysteretic curve of the multi-leaf spring. Static and dynamic tests are performed to verify the reliability of the presented techniques. The tests are performed with various amplitudes and excitation frequencies. The hysteretic curves from the tests are compared with those from the simulations. Since th e presented techniques reproduce the hysteretic characteristic of the multi -leaf spring faithfully, they contribute on improving the reliability of the computational model of a large truck.

• Geotechnical Engineering
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• v.10 no.4
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• pp.167-180
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• 1994

A series of long term consolidation tests were conducted under loading -unloading and loading(pc) -unloading(p.) -reloading(p,) conditions using reconstituted clay in order to investigate the effect of stress history on secondary consolidation characteristics and the applicability of the secondary consolidation model suggested by Bjerrum to overconsolidated clays. According to the test results, the secondary compression settlement affected by the stress history in the first half of experimental period and the coefficient of secondary compression, C‥‥ is dependent on overconsolidation ratio, OCR(p,1 p.), maBium OCR (p./p.), and unloading duration time. Moreover the coefficient of secondary consolidation in the latter half of experimental period Cn is mainly affected by OCR and it gradually reduces with OCR increment. Finally the comparison of the experimental results with the Bjerrum model indicates that the Bjerrum model can be applied beyond certain range of stress history in the overconsolidated clay.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.61-62
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• 2023

There have been cases where the number of port workers has temporarily decreased due to COVID-19. To prevent the spread of COVID-19, a number of workers were quarantined, resulting in bottlenecks and waiting throughout the port operation process, increasing the congestion of terminals. As a result, problems such as a decrease in terminal operation efficiency occurred. However, it is understood that congestion centered on unloading equipment inside the terminal is not clearly calculated. Terminal congestion is thought to be a key factor directly related to the operational efficiency of the terminal. The congestion calculation method generally used in various fields measures congestion based on image-based data. Due to the nature of the loading and unloading equipment that moves according to the quantitative loading plan, it is unreasonable to apply the existing congestion calculation method. Therefore, this study presented a method of calculating terminal congestion using equipment waiting time and turnaround time, and verified the statistical significance of the congestion calculated using data from Terminal A of Busan Port.

• Journal of The Korea Institute of Healthcare Architecture
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• v.14 no.2
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• pp.53-64
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• 2008

This study is the architectural planning of 5 distribution supporting facilities for traditional herbal medicine cultivated in the rural areas. The main function of the facility consists of storage, pre-treatment/processing, loading/unloading and the assistant function consists of inspection, office, exhibition/sale, technical equipment etc. The planning shows the modular plan and the section plan of the storage space reflecting the shape and size of storage container, the action radius of carrier and the possibilities of space lease. The total floor area of the storage is 3,192$m^2$ consisting of 27 space. The total floor area of the pre-treatment/processing is 1,488$m^2$ consisting of 7 space. The total floor area of the loading/unloading is 329$m^2$ consisting of 4 space. The total floor area of each facility storage is 8,284$m^2$ including of public space 2,170$m^2$. Also this planning shows the preliminary design, "fundamental model design" for 5 rural government BTL project. Therefore, this result of planning will be the guidelines of the RFP(Request For Proposal) for the private sector company interested in this BTL project.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.241-249
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• 2002

Optical fiber is indispensable for optical communication systems that transmit large volumes of data at high speed, but super precision technology in sub-micron units is required for optical axis adjustment. We developed the automatic optical fiber by image processing and automatic loading system. we have developed 6-axis micro stage system for I/O optical fiber arrays, the initial automatic aligning system software for a input optical array by the image processing technique, fast I/O-synchronous aligning strategy, the automatic loading/unloading system and the automatic UV bonding mechanism. In order to adjust the alignment it used on PC based motion controller, a $10{\mu}m$ repeat-detailed drawing of automatic loading system is developed by a primary line up for high detailed drawing. Also, at this researches used the image processing system and algorithm instead of the existing a primary hand-line up and fiber input array and waveguide chip formed in line by automatic.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.315-320
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• 2009

In this paper we presents an approach to evaluating the performance of freight railway stations based on several performance indicators as an alternative to the evaluation based on single indicator. Such evaluation needs a way to weight the importance of the individual performance indicator. Data envelopment analysis (DEA) suggested by Charnes, Cooper, and Rhodes (1978) can be used to determine the weights. Using DEA we evaluate 353 freight railway stations based on four performance indicators: loading volume, unloading volume, loading revenue, unloading revenue. The evaluation results facilitates the organization's decision making by providing valuable information.

• Korean Journal of Materials Research
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• v.25 no.5
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• pp.221-225
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• 2015

In-situ neutron diffraction has been employed to examine the effect of strain path on lattice strain evolution during monotonic and cyclic tension in an extruded Mg-8.5wt.%Al alloy. In the cyclic tension test, the maximum applied stress increased with cycle number. Lattice strain data were acquired for three grain orientations, characterized by the plane normal to the stress axis. The lattice strain in the hard {10.0} orientation, which is unfavorably oriented for both basal slip and {10.2} extension twinning, evolved linearly throughout both tests during loading and unloading. The {00.2} orientation exhibited significant relaxation associated with {10.2} extension twinning. Coupled with a linear lattice strain unloading behavior, this relaxation led to increasingly compressive residual strains in the {00.2} orientation with increasing cycle number. The {10.1} orientation is favorably oriented for basal slip, and thus showed a soft grain behavior. Microyielding occurred in the monotonic tension test and in all cycles of the cyclic test at an applied stress of ~50 MPa, indicating that strain hardening in this orientation was not completely stable from one cycle to the next. The lattice strain unloading behavior was linear in the {10.1} orientation, leading to a compressive residual strain after every cycle, which, however, did not increase systematically from one cycle to the next as in the {00.2} orientation.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.417-424
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• 2022

In this paper, the developed trunk cargo unloading automation system is introduced, and the RGB-D sensor-based box loading situation recognition method and unloading plan applied to this system are suggested. First of all, it is necessary to recognize the position of the box in a truck. To do this, we first apply CNN-based YOLO, which can recognize objects in RGB images in real-time. Then, the normal vector of the center of the box is obtained using the depth image to reduce misrecognition in parts other than the box, and the inner wall of the truck in an image is removed. And a method of classifying the layers of the boxes according to the distance using the recognized depth information of the boxes is suggested. Given the coordinates of the boxes on the nearest layer, a method of generating the optimal path to take out the boxes the fastest using this information is introduced. In addition, kinematic analysis is performed to move the conveyor to the position of the box to be taken out of the truck, and kinematic analysis is also performed to control the robot arm that takes out the boxes. Finally, the effectiveness of the developed system and algorithm through a test bed is proved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.88-94
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• 2021

Currently, the Busan cooperative fish market follows a traditional market style. This study first investigates the current conditions and environment of the market, and to modernize the market, it proposes a new automatic unloading system based on the benchmark of Namhae Suhyup. In this system, a Korean-type suction fish vacuum pump is employed to increase the loading time. An automatic grader with an adjusting device for inclined angles and a weighing machine with an automatic alignment device are proposed. In addition, a folding machine is employed to prepare boxes. The specifications for each subsystem are provided. By implementing this system, the freshness of fish can be maintained and the sellers can earn more. This system can also be applied to the cooling system of the fish reservoir of littoral sea fishing boats.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1259-1266
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• 2022

Stowage planning is an essential process for safe loading by establishing, agreeing on, and systematically implementing a reasonable loading and securing method based on information on cargo, loading/unloading and the ship. In addition, depending on the plan, there may be a difference of about 14% or more in the loading amount per ship, which causes a tolerance rate and leads to an increase in sea freight charges. In this study, work environment and process standards for steel coil shipment, and classification regulations and guidelines related to steel coil shipment were analyzed. In addition, we developed a steel coil loading and placement automation system that derives an optimal loading plan through performance data-based shipping balancing and stability analysis.