• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.1-7
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• 2007

This study introduces an elastic parabolic cable element for initial shaping analysis of cable-stayed bridges. First, an elastic catenary cable theory is shortly summarized by deriving the compatibility condition and the tangent stiffness matrices of the elastic catenary cable element. Next, the force-deformation relations and the tangent stiffness matrices of the elastic parabolic cable elements are derived from the assumption that sag configuration under self-weights is small. In addition the equivalent cable tension is defined in the chord-wise direction. Finally, to confirm the accuracy of this element, initial shaping analysis of cable-stayed bridges under dead loads is executed using TCUD in which stay cables are modeled by an elastic parabolic cable and an elastic catenary cable element, respectively. Resultantly it turns that unstrained lengths of stay cables, the equivalent cable tensions, and maximum tensions by the parabolic cable element are nearly the same as those by the catenary cable elements.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.1
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• pp.105-119
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• 2011

In order to develop the indicators which evaluate the management effectiveness for the protected forest areas in Korea, candidate indicators were listed based on literature and experts interviews, then questionnaire survey on the experts were conducted. 5 elements of context, planning, input, process, output and outcome and 32 indicators were selected. Context element includes 6 indicators of 1) documentation and assessment of values; 2) documentation and assessment of threats, 3) influence of government policy, 4) related regulations, 5) community cooperation and 6) the structure of management organization. 6 indicators of Planning element were 1) the management objective, 2) protected area design, 3) protected area size and number, 4) representation, 5) standards and categories and 6) management planning. Input element of 3 indicators were 1) management staff, 2) funding, 3) establishment and application of information. Process element were consisted of 1) governance, 2) management guidelines, 3) human resource management, 4) law enforcement, 5) eco-management, 6) disaster management, 7) education program and 8) research and monitoring. The element of outputs and outcomes were 1) accomplishment of plan, 2) accomplishment of program, 3) private land management, 4) threats change, 5) biodiversity change, 6) ecosystem health and vitality, 7) impact on community, 8) international management level and 9) visitors' satisfaction and variation in civil compliant. It is recommended to have further research on evaluation methods development by applying those above developed indicators for the protected forest areas to ensure the practicality of the indicators.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2391-2396
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• 2010

The power-controlled six-port element that can control the local oscillator signal power and receiving RF signal power was designed and implemented in this paper. The direct conversion six-port element configuration was proposed, which provides the constant six-port output power by controlling the six-port input power with various signal strength. The direct conversion six-port element protects the power detector element of six-port receiver from the saturation status and compensates the transmission performance degradation. For implementation of power-controlled six-port element, the power-controlled six-port element including the power controller was analyzed. The implemented power-controlled six-port element shows the power control capability of 36 dB and gain imbalance of about 1.6 dB, phase imbalance of about $4^{\circ}$ in the frequency range of 1.69 GHz. The measured results show the good performance as direct conversion front-end element.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.859-865
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• 2007

This paper presents a method to analyze the unbalance response of a high speed polygon mirror scanner motor supported by sintered bearing and flexible supporting structures by using the finite element method and the mode superposition method. The appropriate finite element equations for polygon mirror are described by rotating annular sector element using Kirchhoff plate theory and von Karman non-linear strain, and its rigid body motion is also considered. The rotating components except for the polygon mirror are modeled by Timoshenko beam element including the gyroscopic effect. The flexible supporting structures are modeled by using a 4-node tetrahedron element and 4-node shell element with rotational degrees of freedom. Finite element equations of each component of the polygon mirror scanner motor and the flexible supporting structures are consistently derived by satisfying the geometric compatibility in the internal boundary between each component. The rigid link constraints are also imposed at the interface area between sleeve and sintered bearing to describe the physical motion at this interface. A global matrix equation obtained by assembling the finite element equations of each substructure is transformed to a state-space matrix-vector equation, and both damped natural frequencies and modal damping ratios are calculated by solving the associated eigenvalue problem by using the restarted Arnoldi iteration method. Unbalance responses in time and frequency domain are performed by superposing the eigenvalues and eigenvectors from the free vibration analysis. The validity of the proposed method is verified by comparing the simulated unbalance response with the experimental results. This research also shows that the flexibility of supporting structures plays an important role in determining the unbalance response of the polygon mirror scanner motor.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.29-36
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• 2008

In this paper, the orbital forming analysis of an automotive hub bearing was studied to predict forming performances using the explicit finite element method. To find an efficient solution technique for the orbital forming, axisymmetric finite element models and 3D solid element models were solved and numerically compared. The time scaling and mass scaling techniques were introduced to reduce the excessive computational time caused by small element size in case of the explicit finite element method. It was found from the numerical simulations on the orbital forming that the axisymmetric element models showed the similar results to the 3D solid element models in forming loads whereas the deformations at the inner race of bearing were quite different. Finally the strains at the inner race of bearing and the forming forces to the peen were measured for the same product of the numerical model by test, and were compared with the 3D solid element results. It was founded that the test results were in good agreements with the numerical ones.

• Korean Institute of Interior Design Journal
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• v.22 no.2
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• pp.186-193
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• 2013

In the commercial space, the modern consumers want to consume not only product but also culture. Thus, the modern commercial space tries to induce the customer's concern and purchase to the differentiated design. The introduction of this 'the natural element' delivers the pleasure and stability to the consumer buying process and availability is enlarged. Therefore, the purpose of study is gain that expression and characteristic method of the natural element in the commercial space. The detailed study method are as follows. First, the study looks into the natural element expression tendency in the modern space. Second, the expression type of the natural element was classified as 'Reappearance', 'Transformation', and 'Fuse' based on the preceding research. And according to the content of the expression type, subdivided method of 'Inclusion' and 'Replication' of 'Reappearance' and method of 'Imitation' and 'Association' of 'Transformation' and method of 'Juxtaposition' and 'Combine' of 'Fuse'. Third, the result of analyze the characteristic of expression of the natural element of the besides the commercial space case 20 place is as follows. First, 'Inclusion' of 'Reappearance' introduced the external scenery or planned garden as the inside through the opening. 'Replication' is used for decorative purposes or functional purposes as the natural element. 'Imitation' of 'Transformation' imitated the form, pattern, and color of the natural element and was mainly expressed in the wall and objet. The method of 'Association' expressed the concept of the natural element for the whole of the space and a portion of the wall and objet repetitively. As for 'Juxtaposition', mixture of 'Reappearance' had a good visual effect, because it can be obtained the external-internal nature. As for 'Combine', mixture of 'Replication' and 'Imitation' was the most common method. Thus, the study results are expected to be utilized as base date in designing the commercial with development of the natural element application method.

• Composites Research
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• v.30 no.6
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• pp.338-342
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• 2017

In this paper, evaluation method of structural integrity of cylindrical composite lattice structures was conducted. A finite element analysis was used to evaluate the structural integrity of composite lattice structures. In order to verify the optimal finite element in the evaluation of the structural integrity, finite element models for cylindrical composite lattice structure were generated using beam, shell and solid elements. The results of the finite element analyses with the shell and solid element models showed a good agreement. However, considerable differences were found between the beam element model and the shell and solid models. This occurred because the beam element does not take into account the degradation of the mechanical properties of the non-intersection parts of cylindrical composite lattice structures. It was found that the finite element analysis of evaluation of structural integrity for cylindrical composite lattice structures have to use solid element.

• Archives of Plastic Surgery
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• v.40 no.3
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• pp.192-197
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• 2013

Background To construct a sophisticated three-dimensional framework, numerous modifications have been reported in the literature. However, most surgeons have paid little attention to the anatomical configuration of the concha and more to its deepness and hollowness, leading to unsatisfactory outcomes. Methods For a configuration of the concha that is definitely anatomical, the author further developed and employed the conchal bowl element, which has been used by several surgeons although the results have not been published elsewhere. The author constructed the conchal bowl element in one of three patterns according to the amount of available cartilages: one block, two-pieces, or a cymba bowl element only. A total of 20 patients underwent auricular reconstruction using a costal cartilage framework between 2009 and 2012. The 8 earliest reconstructions were performed without a conchal bowl element and the latter 12 with a conchal bowl element. The patients were followed up for more than 1 year. The aesthetic results were scored by evaluating characteristics involving the stability of the crus helicis, the conchal definition, and the smoothness of the helical curve. Results The ears reconstructed early without a conchal bowl element showed a shallow and one or two incompletely separated concha with an obliterated cymba conchal space. They also did not have a realistic or smooth curve of the helix because of an unstable crus helicis. However, ears reconstructed later with the concha bowl element showed a definite crus helicis, deep cymba conchal space, and smooth helical curve. Conclusions The construction of the conchal bowl element is simple, not time-consuming procedure. It is suggested that the conchal bowl element must be constructed and attached to the main framework for natural configuration of the reconstructed ear.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.13-18
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• 2016

Humidifiers are used to control indoor humidity. Element-type humidifiers have the advantages of simple structure and low energy consumption, and Japanese products have been widely used for the humidifying elements. In this study, a new humidifying element made of cellulose and PET was developed, and the performance was compared with that of a Japanese element. The mass transfer rates and pressure drops were measured for an element installed at the entrance of a suction-type wind tunnel. The humidification efficiency of the new element was 2 to 4% greater and the pressure drop was 23 to 32% smaller compared to the Japanese element. The mass transfer effectiveness ($j_m/f$) of the new element is also 5 to 28% higher. However, the water absorption capacity was smaller than that of the Japanese element, meaning further development is needed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.4
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• pp.199-206
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• 2018

In this study, numerical analysis is applied to a two - dimensional model for verifying the general finite element program, Abaqus' s extended finite element method(XFEM). The cohesive element model used in the existing research has a limitation in simulating the actual crack because of the disadvantage that the crack path should be predicted and the element should be inserted. For this reason, the extended finite element method(XFEM), which predicts the path of cracks based on the directionality and specificity of stress, is emerging as a new solution in crack analysis. The validity of the XFEM application was confirmed by comparing the cohesive element analysis with the XFEM analysis by applying the crack path to the self - evident two - dimensional model. Numerical analysis confirms stress distribution and stress specificity immediately before crack initiation and compares it with actual crack initiation path. Based on this study, it is expected that cracks can be simulated by performing actual crack propagation analysis of complex models.