• Clinics in Shoulder and Elbow
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• v.18 no.2
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• pp.86-90
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• 2015

Background: Although there are several methods for evaluating bone quality, Hounsfield units (HU), a standardized computed tomography (CT) attenuation coefficient, provide a useful tool for estimating focal bone mineral density (BMD). The aim of this study is to investigate the HU for evaluating the degree of osteoporosis in greater tuberosity with regard to anchor positioning. Methods: Forty patients diagnosed as normal on shoulder CT were included and categorized according to age and gender. Axially sectioned CT images were processed to 3-dimensional models containing information about bone quality using Mimics (14.11 platform v14.1.1.1 Materialise). Three-dimensional anchors were simulated and positioned according to 6 regions of interest (ROI) in the greater tuberosity classified using Tingart's system. Mean HU of intra-anchor volumes in the 6 regions was measured. Results: A significant decrease in HU was observed with increasing age (p=0.0001) and menopause (p<0.001). A significant difference in HU was found between male and female groups with males showing the higher values (p=0.0001). HU of proximal areas of ROI was higher than those of distal areas (p<0.005). However, although mean HU of distal posterior ROI showed the lowest values, no statistically significant difference was found between anterior, middle, and posterior regions (p=0.087). Conclusions: Mean HU of ROIs provides a tool for preoperative assessment of focal BMD, which is a factor of suture anchor stability and can be used to aid decision-making regarding secure anchor positioning for rotator cuff repair. Our data support that the most secure point is the proximal regions of ROI.

• The Journal of Korea Robotics Society
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• v.11 no.3
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• pp.127-132
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• 2016

For a practical mobile robot team such as carrying out a search and rescue mission in a disaster area, the localization have to be guaranteed even in an environment where the network infrastructure is destroyed or a global positioning system (GPS) is unavailable. The proposed architecture supports localizing robots seamlessly by finding their relative locations while moving from a global outdoor environment to a local indoor position. The proposed schemes use a cooperative positioning system (CPS) based on the two-way ranging (TWR) technique. In the proposed TWR-based CPS, each non-localized mobile robot act as tag, and finds its position using bilateral range measurements of all localized mobile robots. The localized mobile robots act as anchors, and support the localization of mobile robots in the GPS-shadow region such as an indoor environment. As a tag localizes its position with anchors, the position error of the anchor propagates to the tag, and the position error of the tag accumulates the position errors of the anchor. To minimize the effect of error propagation, this paper suggests the new scheme of full-mesh based CPS for improving the position accuracy. The proposed schemes assuring localization were validated through experiment results.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1666-1672
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• 2008

In this study, it collected and analyzed a construction case of the improved top-down support system application field on a case by case retaining wall method. The behavior of horizontal displacement was analyzed according to retaining wall type after reviewing a design stage and estimated horizontal displacement under the construction. The study results showed that it is judged stable until excavation termination irrelevant to a retaining wall method at the improved top-down support system application. It is judged that the settlement of behind ground can minimize because the retaining wall head displacement also behave stably. It was compared the predicted horizontal displacement in design and the measured horizontal displacement acquired through a measurement by using Elasto-Plastic analysis program. The comparison results showed that a similar horizontal displacement was predicted within stability standard irrelevant to a retaining wall method. So, it is decided that the advanced prediction is reasonable by Elasto-Plastic analysis in design applied the improved top-down support system. In the case of the ground anchor method application under a same condition, it is decided that a horizontal displacement will more increase than the improved top-down support system is applied. If a section condition is same, it was decided that to apply top-down support system is more stable than that.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.565-580
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• 2006

Set in constant increase and period current of lively technical development of railroad use and construction of cable stayed bridge railway bridge, one of bridge form of most suitable that think side police officer and the material enemy of bridge that use long rail, is increasing laying stress on the foreign countries. Main tower fixing department of this cable stayed bridge is consisted of main tower flange that support bearing plate, bay ring plate bearing plate, support end rib and diaphragm etc, as stress transmission mechanic that tensility of cable socket into normal force of main tower, and is used this time. These structural elements is very complex the structure and direction of load delivered from socket specially calbe particularly be different, and need FEM analysis that use Thick Shell element for suitable arrangement of mutual stress flowing grasping and absence that follow hereupon because all of the each support plate angle that suport this differ.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.136-144
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• 1997

Usually triangular patches are used to transfer geometric shape in Rapid Prototyping CAM system. STL, a list of triangles, is de facto standard in RP industry. Because STL does not have topological infoma- tion, it can cause errornous results. So STL should be verified before using. After adding support structures to anchor the part to the platform and to prevent sagging or distortion, slicing and layer by layer manufactur- ing process are done. But triangular patch is surface model and cannot provide sufficient information on geometry in the above processes. So, geometric modeling is necessary in verifying STL, adding support structures and slicing. It is natural that triangle based modeling is the best when tringular patches are used as input. Considering support structures, solid and faces coexist in RP process. Therefore non-manifold modeler is required. In this study, triangle based non-manifold geometric modeling is proposed for RP sys- tem consistent with STL input.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.14-20
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• 2014

In this study, the stress analysis for the piping support design is performed as per the rules of the ASME Code, Section III, subsection NF-Component Support which provides a simplified method of design analysis for piping support. This method makes use of simple equations and conservative allowable stress limits for design and service loadings. For the base plate, code equation is satisfied within the allowable limits. Both anchor bolts and pipe strap are governed by the their interaction equations. The stresses resulting from various loadings and their combinations are within the allowable limits specified in the above mentioned ASME Code. Thus, it was proved that the structural integrity of the pump assembly was satisfactory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.321-326
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• 1997

This paper present how VRML file format can be used for RP Technology. VRML standards provids compact and powerful interface between remote RP manufacturer in network independent environment. We have constructed integrated and network-connected server system which can share the CAD data and varios process which is STL-to-VRML translater,slicing process,slice anchor process etc. This Server system consisted in file converter between STL and VRML,CGI system which sends a generated data to VRML client or browser, slice-generator which can re-slice at varied thickness and simulator which can show and check simultaneously status between near slices with support. This system aims to the integrated simulator which supports graphic animator and FEA analysis system.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.507-518
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• 2023

The effects of various supporting arrangements have been investigated on an excavation support system using a numerical tool. The purpose of providing different supporting arrangements was to limit the pile wall deflection in the range of 0.5% to 1% of the excavation depth. Firstly, a deep excavation supported by sheet pile wall was modeled and the effects of sheet pile wall thickness, excavation depth and distance to adjacent footings from sheet pile wall face were explored on the soil deformation and wall deflection. Further analysis was performed considering six different arrangements of tieback anchors and struts in order to limit the wall deflections. Case-01 represents the basic excavation geometry supported by sheet pile wall only. In Case-02, sheet pile wall was supported by struts. Case-03 is a sheet pile wall supported by tieback anchors. Likewise, for the Cases 04, 05 and 06, different arrangements of struts and tieback anchors were used. Finally, the effects of different supporting arrangements on soil deformation, sheet pile wall deflection, bending moments and anchor forces have been presented.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.28-37
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• 1996

To reduce an authors burden in hypermedia system that allows non-sequential information the process of creating links must be easy. However, most of the conventional hypermedia systems possess two difficulties. First, the author must go through several troublesome process to create a single link. Secondly, it is not easy to create an anchor in text or other multimedia data. Therefore, in order to support effective construction of hypermedia system the editing environment must provide an easy method to create links. In this paper, to resolve the weaknesses of conventional hypermedia system as mentioned above, an editing tool is developed and implemented to easily create the links of multimedia data. There are three methods in creating links and a user can select a convenient method in given circumstances. And for teh efficient production of nodes composed of multimedia information, we provide an authoring environment to integrate and process those informations.

• Geomechanics and Engineering
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• v.37 no.3
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• pp.293-306
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• 2024

Influenced by the alternating effects of dynamic and static pressure during the mining process of close range coal seams, the surrounding rock support of cross mining roadway is difficult and the deformation mechanism is complex, which has become an important problem affecting the safe and efficient production of coal mines. The paper takes the inclined longwall mining of the 10304 working face of Zhongheng coal mine as the engineering background, analyzes the key strata fracture mechanism of the large inclined right-angle trapezoidal mining field, explores the stress distribution characteristics and transmission law of the surrounding rock of the roadway affected by the mining of the inclined coal seam, and proposes a segmented and hierarchical support method for the cross mining roadway affected by the mining of the close range coal seam group. The research results indicate that based on the derived expressions for shear and tensile fracture of key strata, the ultimate pushing distance and ultimate suspended area of a right angle trapezoidal mining area can be calculated and obtained. Within the cross mining section, along the horizontal direction of the coal wall of the working face, the peak shear stress is located near the middle of the boundary. The cracks on the floor of the cross mining roadway gradually develop in an elliptical funnel shape from the shallow to the deep. The dual coupling support system composed of active anchor rod support and passive U-shaped steel shed support proposed in this article achieves effective control of the stability of cross mining roadways, which achieves effective control of floor by coupling active support and preventive passive support to improve the strength of the surrounding rock itself. The research results are of great significance for guiding the layout, support control, and safe mining of cross mining roadways, and to some extent, can further enrich and improve the relevant theories of roof movement and control.