• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.2
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• pp.111-117
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• 1990

The hydraulic line haulers are now widely used to haul the main line, but the other hauling operations are still done manually in most pot fisheries. The oval type hooks which are connected between the loops and the post are tested for basic capability by the universal tension meter in order to develop the automatic separating system. The pots attached to the oval type hooks are separated automatically from the loops while the oval type hooks are running through the trumpet separator with the side roller and the results are as follows: 1. The tension of the large oval hooks (ø3.1mm) for missing pots and the compressive load at the end of hooks by hand are about 60kg and 6kg, and range of tension for passing through the trumpet is 11~15kg. 2. Automatic separating ratio of the pots with the large oval hooks is about 99% when the trumpet separator is attached to front or rear of the side roller in the laboratory. 3. The separating ratio of the pot with the large oval hooks while hauling operation in the sea is about 97% when the trumpet separator is oriented on the port bulwark departed 2m from the side roller.

• The Journal of Bigdata
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• v.1 no.2
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• pp.9-19
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• 2016

Since ICT convergence became a major issue, German government has carried forward a policy 'Industry 4.0' that triggered ICT convergence with manufacturing. Now this trend gets into our stride. From this facts, we can expect great leap up to quality perfection in low cost. Recently Korean government also enforces policy with 'Manufacturing 3.0' for upgrading Korean manufacturing industry with being accelerated by many related technologies. We, in the paper, developed a custom-made operational big data analysis platform for the implementation of operational intelligence to improve industry capability. Our platform is designed based on spring framework and web. In addition, HDFS and spark architectures helps our system analyze massive data on the field with streamed data processed by process mining algorithm. Extracted knowledge from data will support enhancement of manufacturing performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.609-617
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• 2014

Even though the variable pitch control of a wind turbine blade is known as an effective component for power control over the rated wind speed, it has limited applicability to small wind turbines because of its relatively high cost on the price of small wind turbine. Instead, stall control is generally applied in the blade design without any additional cost. However, stall delay can frequently be caused by high turbulence around the turbine blade, and it can produce control failures through excessive rotational speed and overpowering the electrical generator. Therefore, a passive pitch control module should be considered, where the pitch moves with the aerodynamic forces of the blade and returns by the elastic restoring force. In this study, a method to calculate the pitch moment, torque, and thrust based on the lift and drag of the rotating blade wing was demonstrated, and several effective wing shapes were reviewed based on these forces. Their characteristics will be estimated with variable wind speed and be utilized as basic data for the design of the passive pitch control module.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.57-69
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• 1990

The static nonlinear analysis of offshore pipeline is carried out by the finite element method. The governing equilibrium equation are derived by the principle of minimum potential energy and the modified Newton-Raphson procedure is used to solve the system of nonlinear algebraic equation. Geometrically nonlinear beam elements and spring elements are utilized to model the pipeline, stinger, pipe supports and seabed simultaneously. The beam element developed can be used to model redundant structures. It provides for both the torsional deformation and elongation of pipeline, and permits the use of different physical properties in each principal direction. The validity of this method is investigated by comparing the results with these obtained by other methods.

• Science of Emotion and Sensibility
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• v.5 no.1
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• pp.1-7
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• 2002

This paper studies on the human cognition of object's weight in virtual environment. We design the force input device which consists of a 3D mouse and a simple spring. It provides users with force feedback. The user can measure the weight of an object by the grasping force to move or lift it up in the virtual environment. Three kinds of experiments are performed. The first one is performed to analyze the relationships between the object's weight and its volume. The second one is to find the relationships between the object's weight and the its texture and finally the third one is to find the relationships between the object's weight and the force used to move an object. We conclude from the analysis of the experiment that object's volume or texture are not the critical factor for user to realize its weight. But the grasping force is critical and meaningful in realizing its weight so that the virtual environment with force cue provides users with more immersive environments. And, also the force input device is effective enough for user to feel the weight of the object.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.3
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• pp.137-151
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• 1991

The motion of two-dimensional floating breakwaters with rectangular clots-section which are moored tautly in shallow water has been analyzed using a velocity potential matching method in which the fluid region is devided into sub-regions and then unknown coefficients of velocity potentials are determined from the continuity condition of mass and momentum flux of fluid at imaginary boundaries between sub-regions. The method originally suggested by Ijima et al.(1972) for the motion of submerged body has been modified to analyze the motion of floating body. The total fluid region has been divided into three sub-regions : the incident wave region, the transmitted wave region and the region below the floating breakwater. The restoring forces induced by mooring lines which were ignored by Ijima et al.(1972) have been modeled as linear springs with the initial tension effects. This method has been verified through the comparions with results from hydraulic expriments. Applications to various conditions of floating breakwater have been performed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.4
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• pp.347-355
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• 2008

In this paper single degree of freedom macro-element model was presented to investigate the interaction between soil and the deep foundation under the lateral loads. It was made by modelling each component related to the soil-structure interaction and combining them into one piece. It enhanced the conventional method that was not able to break down the interaction components in piece due to the usage of simple spring element for interaction. A proposed macro-element classified the stress components in relation to the interaction into frictional and compressive resistance. Each component was modelled using the classical plasticity theory, and finally combined in parallel. An example study was carried out using the proposed macro-element for deep foundation embedded in three layered cohesive soil. It showed improved results compared to the conventional method by producing additional information of the interaction components as well as the overall behavior of foundation.

• Journal of Aerospace System Engineering
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• v.12 no.5
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• pp.69-75
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• 2018

In this study, we proposed a nylon wire cutting-type solar panel separation mechanism for CubeSat applications using spring-loaded pogo-pins, which has been widely used as temporary electrical interface between two separate electronics. The mechanism proposed in this study has great advantages of higher holding capability, ability to constrain along in-plane and out-of-plane directions of solar panels, simplicity in tightening of nylon wire and synchronous separation of multiple panels. In addition, the pogo-pins used for the proposed mechanism act as electrical power interface, separation status switch and separation spring. In this study, the functionality of the proposed mechanism was validated through the separation tests with various number of nylon wire windings.

• Journal of the Korean Society for Railway
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• v.14 no.1
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• pp.11-18
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• 2011

This paper proposed a new 2-D multi-body dynamic modeling technique to analyze overriding behaviors taking place during train collision. This dynamic model is composed of nonlinear springs, dampers and masses by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model for rollingstock, energy absorbing capacities of collision elements, accelerations of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we chose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3-D finite element analysis, and established a 2-D multi-body dynamic model. This 2-D dynamic model was simulated under the train-to-train collision scenarios, and evaluated with 3-D virtual testing model. It was founded from the simulation results that this 2-D dynamic model could well predict overriding behaviors, and the modeling technique of carbody deformation was very important in overriding estimation.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.47-58
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• 2005

Dynamic response analysis in time dimain is conducted for floating bridges with discrete pontoons subject to spatial variation of ground motions. The Spatial variation of ground motions is considered with the coherency function model which represents wave passage, incoherence and local site effects. The superstructure of the bridge is represented by space frame and elastic catenary cable elements, the abutment us modelde with the spring element of FHWA guideline for considering soil structure interaction and the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients which are obtainde by boundary element method. multiple support excitations considering the spatial variation. The noticeable amplification of the response can be shown when the spatial variation of ground motions is incorporated in the anallysis of floating bridges.