• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.3
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• pp.215-230
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• 2012

An experimental research on the possibility of using high-strength concrete with the design strength of 60 MPa and high-tension rebar with the yielding strength of 600 MPa instead of conventional reinforced concrete segment to reduce its production cost was performed. Full-scale bending tests on both conventional and high-strength reinforced concrete segments were carried out to compare their mechanical and structural behaviors of the segments under flexural action. From the experiments, it was shown that the failure load of high-strength reinforced concrete segment was approximately 30% higher than that of the conventional segment even though reinforcements in high-strength segment were reduced by 26%. The test result showed that the bearing capacity of high-strength segment highly increased by high-strength concrete and high-tension rebar. It also verified the high possibility of high-strength reinforced concrete segment as a technical alternative to reduce the production cost of segments in a shield tunnel.

• Steel and Composite Structures
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• v.24 no.4
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• pp.481-497
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• 2017

In this paper, full-scale loading tests were performed on a rectangular segmental tunnel lining, which was assembled by steel composite segments, to investigate its load-bearing structural behavior and failure mechanism. The tests were also used to confirm the composite effect by adding concrete inside to satisfy the required performance under severe loading conditions. The design of the tested rectangular segmental lining and the loading scheme are also described to better understand the bearing capacity of this composite lining structure. It is found that the structural ultimate bearing capacity is governed by the bond capacity between steel plates and the tunnel segment. The failure of the strengthened lining is the consequence of local failure of the bond at waist joints. This led to a fast decrease of the overall stiffness and eventually a loss of the structural integrity.

• Smart Structures and Systems
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• v.15 no.1
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• pp.99-117
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• 2015

The Stonecutters Bridge (SCB) in Hong Kong is the third-longest cable-stayed bridge in the world with a main span stretching 1,018 m between two 298 m high single-leg tapering composite towers. A Wind and Structural Health Monitoring System (WASHMS) is being implemented on SCB by the Highways Department of The Hong Kong SAR Government, and the SCB-WASHMS is composed of more than 1,300 sensors in 15 types. In order to establish a linkage between structural health monitoring and maintenance management, a Structural Health Rating System (SHRS) with relevant rating tools and indices is devised. On the basis of a 3D space frame finite element model (FEM) of SCB and model updating, this paper presents the development of an SHR-oriented 3D multi-scale FEM for the purpose of load-resistance analysis and damage evaluation in structural element level, including modeling, refinement and validation of the multi-scale FEM. The refined 3D structural segments at deck and towers are established in critical segment positions corresponding to maximum cable forces. The components in the critical segment region are modeled as a full 3D FEM and fitted into the 3D space frame FEM. The boundary conditions between beam and shell elements are performed conforming to equivalent stiffness, effective mass and compatibility of deformation. The 3D multi-scale FEM is verified by the in-situ measured dynamic characteristics and static response. A good agreement between the FEM and measurement results indicates that the 3D multi-scale FEM is precise and efficient for WASHMS and SHRS of SCB. In addition, stress distribution and concentration of the critical segments in the 3D multi-scale FEM under temperature loads, static wind loads and equivalent seismic loads are investigated. Stress concentration elements under equivalent seismic loads exist in the anchor zone in steel/concrete beam and the anchor plate edge in steel anchor box of the towers.

• Geomechanics and Engineering
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• v.13 no.4
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• pp.621-640
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• 2017

The double-row long-short composite anti-sliding piles system is an effective way to control the landslides with high thrust. In this study, The double-row long-short composite anti-sliding piles with different load segment length (cantilever length) and different pile row spacing were studied by a series of physical tests, by which the influences of load segment length of rear-row piles as well as pile row spacing on the mechanical response of double-row long-short composite anti-sliding pile system were investigated. Based on the earth pressures in front of and behind the piles obtained during tests, then the maximum bending moments of the fore-row and the rear-row piles were calculated. By ensuring a equal maximum moments in the fore-row and the rear-row piles, the optimum lengths of the rear-row piles of double-row long-short composite system under different piles spacing were proposed. To investigate the validity of the reduced scale tests, the full-scale numerical models of the landside were finally conducted. By the comparisons between the numerical and the physical test results, it could be seen that the reduced scale tests conducted in this study are reliable. The results showed that the double-row long-short composite anti-sliding piles system is effective in the distribution of the landslide thrust to the rear-row and the fore-row piles.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.114-123
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• 2003

The current paper proposes a new vertex selection scheme for polygon-based contour coding. To efficiently characterize the shape of an object, we incorporate the curvature information in addition to the conventional maximum distance criterion in vertex selection process. The proposed method consists of "two-step procedure." At first, contour pixels of high curvature value are selected as key vortices based on the curvature scale space (CSS), thereby dividing an overall contour into several contour-segments. Each segment is considered as an open contour whose end points are two consecutive key vortices and is processed independently. In the second step, vertices for each contour segment are selected using progressive vertex selection (PVS) method in order to obtain minimum number of vertices under the given maximum distance criterion ( $D_{max}$$^{*}$). Furthermore, the obtained vortices are adjusted using the dynamic programming (DP) technique to optimal positions in the error area sense. Experimental results are presented to compare the approximation performances of the proposed and conventional methods.imation performances of the proposed and conventional methods.

• The KIPS Transactions:PartB
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• v.12B no.5 s.101
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• pp.527-534
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• 2005

Rotation and scale variations make it difficult to solve the problem of shape description and recognition because these variations change the location of points composing the shape. However, some geometric Invariant points and the relations among them are not changed by these variations. Therefore, if points in image space depicted with the r-y coordinates system can be transformed into a new coordinates system that are invariant to rotation and scale, the problem of shape description and recognition becomes easier. This paper presents a shape description method via transformation from the image space into the invariant feature space having two axes: representing relative distance from a centroid and contour segment curvature(CSC). The relative distance describes how far a point departs from the centroid, and the CSC represents the degree of fluctuation in a contour segment. After transformation, mesh features were used to describe the shape mapped onto the feature space. Experimental results show that the proposed method is robust to rotation and scale variations.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.17-23
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• 2017

The present study investigates the effect of Accentual Phrase on F0 using a subset of large-scale corpus of Seoul Korean. Four syllable words which were neither preceded nor followed by silent pauses were presumed to be canonical exemplars of Accentual Phrases in Korean. These four syllable words were extracted from female speakers' speech samples. Growth curve analyses, combination of regression and polynomial curve fitting, were applied to the four syllable words. Four syllable words were divided into four groups depending on the categorical status of the initial segment: voiceless obstruents, voiced obstruents, sonorants, and vowels. Results of growth curve analyses indicate that initial segment types have an effect on the F0 (in semitone) in the nucleus of the initial syllable, and the cubic polynomial term revealed that some of the medial low tones in the 4 syllable words may be guided by the principle of contrast maximization, while others may be governed by the principle of ease of articulation.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.151-156
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• 2008

The after 1974 capital region electric railroad is opened to traffic Koraill and Seoul metro adopt each other different power supply method and they operate and they are come. AC 25[kv] method voltage the insulation becomes larger standing distance highly, the case tunnel section which will introduce in the underground segment becomes on a large scale and the cost of construction increases to the city center and the underground segment adoption of DC method was many. To recent times with R-bar (Rigid-bar) introductions change of tunnel section the introduction of AC method came to be easy without in the underground segment. Operates sees in the electric protection where the Seoul metro and the Korail are different each other and, from the dead section segment the interior electric light to put out lights the passenger brings about inconveniently and the civil appeal which demands a power supply method unification occurs, within the company interchange electric railroad brazier safety improvement and maintenance expense curtailment etc. the flaw is original proposal, is a condition which finishes a feasibility study service about the power supply method fringe land. Interchange analysis of the DC electric railway it leads from the present paper and it compares under analyzing being it could be reflected to also the route which is in the process of actual using boil the strong point and a weak point of DC and AC method of the establishment route constructive at the time of and

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.26-30
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• 2013

Objective : The purpose of this study was to compare the results of three types of short segment screw fixation for thoracolumbar burst fracture accompanying osteopenia. Methods : The records of 70 patients who underwent short segment screw fixation for a thoracolumbar burst fracture accompanying osteopenia (-2.5< mean T score by bone mineral densitometry <-1.0) from January 2005 to January 2008 were reviewed. Patients were divided into three groups based on whether or not bone fusion and bone cement augmentation procedure 1) Group I (n=26) : short segment fixation with posterolateral bone fusion; 2) Group II (n=23) : bone cement augmented short segment fixation with posterolateral bone fusion; 3) Group III (n=21) : bone cement augmented, short segment percutaneous screw fixation without bone fusion. Clinical outcomes were assessed using a visual analogue scale and modified MacNab's criteria. Radiological findings, including kyphotic angle and vertebral height, and procedure-related complications, such as screw loosening or pull-out, were analyzed. Results : No significant difference in radiographic or clinical outcomes was noted between patients managed using the three different techniques at last follow up. However, Group I showed more correction loss of kyphotic deformities and vertebral height loss at final follow-up, and Group I had higher screw loosening and implant failure rates than Group II or III. Conclusion : Bone cement augmented procedure can be an efficient and safe surgical techniques in terms of achieving better outcomes with minimal complications for thoracolumbar burst fracture accompanying osteopenia.

• Proceedings of the Safety Management and Science Conference
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• 2003.05a
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• pp.291-297
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• 2003

In fact, some cases that successfully introduced CRM show that CRM is migrating from small scale which is typical when introduced to larger scale through various tests. The process also comprises all strategic planning, capital investments, management decisions, and tasks necessary to create a new product. manufacturing processes must be created so that the product can be produced in the product facility Therefore, this study tries to segment customer for the sieving the problem. And it make efficient customer management.