• Title/Summary/Keyword: Mesh Structure

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Use of 3D Printing Model for the Management of Fibrous Dysplasia: Preliminary Case Study

  • Choi, Jong-Woo;Jeong, Woo Shik
    • Journal of International Society for Simulation Surgery
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    • v.3 no.1
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    • pp.36-38
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    • 2016
  • Fibrous dysplasia is a relatively rare disease but the management would be quite challenging. Because this is not a malignant tumor, the preservation of the facial contour and the various functions seems to be important in treatment planning. Until now the facial bone reconstruction with autogenous bone would be the standard. Although the autogenous bone would be the ideal one for facial bone reconstruction, donor site morbidity would be the inevitable problem in many cases. Meanwhile, various types of allogenic and alloplastic materials have been also used. However, facial bone reconstruction with many alloplastic material have produced no less complications including infection, exposure, and delayed wound healing. Because the 3D printing technique evolved so fast that 3D printed titanium implant were possible recently. The aim of this trial is to try to restore the original maxillary anatomy as possible using the 3D printing model, based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. And we molded Titanium mesh to reconstruct three-dimensional maxillary structure during the operation. This prefabricated Titanium-mesh implant was then inserted onto the defected maxilla and fixed. Three dimensional printing technique of titanium material based on the computer simulation turned out to be successful in this patient. Individualized approach for each patient could be an ideal way to restore the facial bone.

Structural Intensity Analysis of Local Ship Structures Using Finite Element Method (유한요소법을 이용한 선체 국부 구조물의 진동인텐시티 해석)

  • Dong-Hwan Lee;Dae-Seung Cho
    • Journal of the Society of Naval Architects of Korea
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    • v.38 no.3
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    • pp.62-73
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    • 2001
  • The interest in evaluation of structural intensity arises for practical reasons, because net energy flow distribution offers information of energy transmission path, positions of sources, and sinks of vibration energy. In this paper, structural intensity analysis of local ship structures using finite element method(FEM) is carried out. The purpose of this analysis is to evaluate the relative accuracy according to mesh fineness. The structural intensity of unstiffened and stiffened plates varying their mesh fineness is analyzed and the results are compared with those obtained by the assumed mode method. As results, the proper mesh size in qualitative/quantitative structural intensity analysis of plate structures is proposed. In addition, the propagation phenomenon of vibration energy is investigated for the thickness-varying flat plate, L-type plate, and box-girder structures.

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A Study on Intrusion Detection Method using Collaborative Technique (협업 기법을 이용한 침입탐지 탐지 방법에 관한 연구)

  • Yang, Hwan Seok
    • Convergence Security Journal
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    • v.21 no.1
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    • pp.121-127
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    • 2021
  • MANET, which does not have any infrastructure other than wireless nodes, has the advantage of being able to construct a fast network. However, the movement of nodes and wireless media are also the causes of security vulnerabilities of MANET. In particular, the damage caused by the attacking nodes existing on the network is considerably greater than that of other networks. Therefore, it is necessary to detection technique for attacking nodes and techniques to reduce damage caused by attacks. In this paper, we proposed a hierarchical structure technique to increase the efficiency of intrusion detection and collaboration-based intrusion detection technique applying a P2P mesh network configuration technique to reduce damage caused by attacks. There was excluded the network participation of the attacking node in advance through the reliability evaluation of the nodes in the cluster. In addition, when an attack by an attacking node is detected, this paper was applied a method of minimizing the damage of the attacking node by transmitting quickly the attack node information to the global network through the P2P mesh network between cluster heads. The ns-2 simulator was used to evaluate the performance of the proposed technique, and the excellent performance of the proposed technique was confirmed through comparative experiments.

An Optimal Algorithm for Weight Balancing in a 3D Mesh Architecture (3D 메쉬 구조에서 무게 균형을 위한 최적 알고리즘)

  • So, Sun Sup;Son, Kyung A;Eun, Seongbae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.8
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    • pp.1095-1101
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    • 2020
  • Vessels or aircraft should be loaded with containers or cargo to maintain weight balance in order to be stable when navigating the route. The container loading algorithm is known as the NP problem and several heuristic methods have been studied. Containers can be characterized by the uniform volume and weight, which makes it easier to find an optimal loading method. In this paper, we propose an algorithm for weight balance when the volume and weight of an object are uniform. It is assumed that the loading space has a special structure of m * n mesh (where m and n are both odd). In this case, we designed a greedy algorithm and proved that the algorithm is optimal in that it can always find a loading position that maintains a weight balance regardless of the number of objects. Our algorithm can be used in many engineering problems, such as loading algorithms and load balancing problems.

Comparison of Augmentation Method for Achilles Tendon Repair: Using Thoracolumbar Fascia and the Polypropylene Mesh

  • Jieun Seo;Won-Jae Lee;Min Jang;Min-Soo Seo;Seong Mok Jeong;Sae-Kwang Ku;Youngsam Kwon;Sungho Yun
    • Journal of Veterinary Clinics
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    • v.40 no.1
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    • pp.16-24
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    • 2023
  • This study aimed to compare complete ruptured tendon healing between two different repair methods using the Achilles tendon of New Zealand white rabbits. Thoracolumbar fascia (TF) padded Kessler suture, polypropylene mesh (PM) padded Kessler suture, and Kessler suture only were performed on the completely transected lateral gastrocnemius tendon, and biomechanical and histologic characteristics were assessed after 8 weeks. For biomechanical assessment, the tensile strength of each repaired tendon was measured according to the established methods. For histomorphometric analysis, hematoxylin and eosin staining for general histology, and Masson's trichrome (MT) staining for collagen fibers, Alcian blue (AB) staining for proteoglycans were performed and analyzed. Significant increases in tensile strength with remarkable decreases in the abnormalities against nuclear roundness, cell density, fiber structure, and fiber alignment and significant decreases in the mean number of infiltrated inflammatory cells and AB-positive proteoglycan-occupied regions with increases in MT-positive collagen fiber-occupied regions were demonstrated in the Kessler suture with PM or TF padding groups as compared to those of the Kessler suture group. Both of PM and TF provided potent tensile strength and supported healing with the evidence of histological examinations. This means that augmentation with PM is useful for repairing a completely ruptured Achilles tendon, without additional surgery for autograft material harvesting.

Development of Liquid Cadmium Cathode Structure for the Inhibition of Uranium Dendrite Growth (수지상 우라늄 성장억제를 위한 액체카드뮴 음극구조 개발)

  • Paek, Seung-Woo;Yoon, Dal-Seong;Kim, Si-Hyung;Shim, Jun-Bo;Ahn, Do-Hee
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.8 no.1
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    • pp.9-17
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    • 2010
  • The LCC (Liquid Cadmium Cathode) structure to be developed for inhibiting the formation and growth of the uranium dendrite has been known as a key part in the electrowinning process for the simultaneous recovering of uranium and TRU (TRans Uranium) elements from spent fuels. A zinc-gallium (Zn-Ga) experimental system which is able to be functional in aqueous condition and normal temperature has been set up to observe the formation and growth phenomena of the metal dendrites on liquid cathode. The growth of the zinc dendrites on the gallium cathode and the performance of the existing stirrer type and pounder type cathode structure were observed. Although the mechanical strength of the dendrites appeared to be weak in the electrolyte and easily crashed by the various cathode structures, it was difficult to effectively submerge the dendrite into the bottom of the liquid cathode. Based on the results of the aqueous phase experiments, a lab-scale electrowinning experimental apparatus which are applicable to the development of LCC srtucture for the electrowinning process was established and the performance tests of the different types of LCC structure were conducted to prohibit the uranium dendrite growth on LCC surface. The experimental results of the stirrer type LCC structures have shown that they could not effectively remove the uranium dendrites growing at the inner side of the LCC crucible and the performances of the paddle and harrow type LCC structure were similar. Therefore a mesh type LCC structure was developed to push down the uranium dendrites to the bottom of the LCC crucible growing on the LCC surface and at the inner side of the crucible. From the experimental results for the performance test of the mesh type LCC structure, the uranium was recovered over 5 wt% in cadmium without the growth of uranium dendrites. After completion of the experiments, solid precipitates of the bottom of the LCC crucible were identified as an intermetallic compound (UCd11) by the chemical analysis.

The Characteristic of Hydrogen Generation on the Structure of Plasma Reactor Using the Streamer Discharge in the Water (수중 스트리머 방전용 플라즈마 반응기 구조에서 수소발생 특성)

  • Park, Jae-Youn;Kim, Jong-Seok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.4
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    • pp.37-42
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    • 2006
  • The effect of arc like streamer discharge is investigated on the hydrogen generation using the multineedle-plate electrode geometry plasma realtor(MPER) and the needle-plate electrode geometry plasma reactor(NPER). In order to restrict waves at the water surface when the high voltage applied, two kinds of the insulator such as the rectangular mesh or the hole mesh type are installed under the water surface. The discharge assistant of the two type(the saw type and the $TiO_2$ pellet type) was placed under the water surface to investigate the effect of the water surface conditions. The experimental results are compared in case of the reactor with and without the discharge assistant on the water surface.

Texture-based Hatching for Color Image and Video

  • Yang, Hee-Kyung;Min, Kyung-Ha
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.4
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    • pp.763-781
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    • 2011
  • We present a texture-based hatching technique for color images and video. Whereas existing approaches produce monochrome hatching effects in considering of triangular mesh models by applying strokes of uniform size, our scheme produces color hatching effects from photographs and video using strokes with a range of sizes. We use a Delaunay triangulation to create a mesh of triangles with sizes that reflect the structure of an input image. At each vertex of this triangulation, the flow of the image is analyzed and a hatching texture is then created with the same alignment, based on real pencil strokes. This texture is given a modified version of a color sampled from the image, and then it is used to fill all the triangles adjoining the vertex. The three hatching textures that accumulate in each triangle are averaged and the result of this process across all the triangles forms the output image. We can also add a paper texture effect and enhance feature lines in the image. Our algorithm can also be applied to video. The results are visually pleasing hatching effects similar to those seen in color pencil drawings and oil paintings.

Dynamic Characteristics Analysis for the Online Monitoring System Designing KTX MRU and Improvement of the Stability Related Variable High Speed (고속열차 감속기의 상시감시시스템 설계 및 가변속주행시 안정성 향상을 위한 동특성해석)

  • Park, Byung Su;Kim, Jin Woo;Choi, Sang Rak;Song, Young Chun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.4
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    • pp.301-307
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    • 2013
  • MRU(motor reduction unit) for KTX is a assembled complex structure that is equipped with a lot of parts at the express train KTX and that is the core power source operating variable speeds. This study is recorded the dynamic characteristics analysis results tested by EMA which is done through the parts and assembly test, transient analysis and stoped train test in order to design the online monitoring system for KTX MRU. And the mode shapes result from critical vibration frequency explain the relation with variable speeds of express train over 250 km/hr. Also these variable speeds make variable operational frequencies at pinion, axle gear mesh frequency and normal bearing fault frequencies. As the specified speed can make resonance with natural frequencies of the MRU, for the train operating stability, this study also presents the MRU's critical speeds calculated by the each train speed.

A Study on the Support System for Midship Structural Analysis (선체중앙부해석 지원시스템 개발에 관한 연구)

  • Shin, Hyun-Kyoung;Son, Ho-Cheol;Kwon, Myung-Joon;Song, Jae-Young;Kim, Jong-Hyun;Lee, Jeong-Ryul;Kang, Ho-Seung;Yeon, Kyu-Jin
    • Journal of Ocean Engineering and Technology
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    • v.12 no.3 s.29
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    • pp.86-95
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    • 1998
  • CAD/CAM program developers have made substantial progress in enabling engineers to design, analyze, visualize, visualize, and simulate the performance of structures and systems. Many researchers, however, agree that there is still a way to go before the existing commercial computer software can be used in ship structural analysis to their full potential as solvers which can identify opportunities to reduce man-hours and cut costs. CAD systems used for these works in ship yards are general-purposed and not custom-tailored for ship structures, which force end-users to do tiresome and routine works. The new preprocessor "MeshGen" announced in this study can load several ship types and user-friendly generate their FE meshes employing the object-oriented approach based on the parametric and top-down design. Also "MeshGen" reduces dramatically the time required to prepare CAD models under window-based environments on desktop personal computers and makes it much easier and faster for end-users to change topology and material properties.

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