• Communications of the Korean Mathematical Society
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• v.24 no.3
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• pp.451-458
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• 2009

The set of root classes plays a crucial role in the Nielsen root theory. Extending Brown et al.'s work on the set of root classes of iterates of maps, we rearrange it into the reduced orbit set and show that under suitable hypotheses, any reduced orbit has the full depth property as in the Nielsen type theory of periodic orbits.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.549-556
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• 2001

The general problems of recovering 3D for 2D imagery require the depth information for each picture element form focus. The manual creation of those 3D models is consuming time and cost expensive. The goal in this paper is to simplify the depth estimation algorithm that extracts the depth information of every region from monocular image sequence with camera translation to implement 3D video in realtime. The paper is based on the property that the motion of every point within image which taken from camera translation depends on the depth information. Full-search motion estimation based on block matching algorithm is exploited at first step and ten, motion vectors are compensated for the effect by camera rotation and zooming. We have introduced the algorithm that estimates motion of object by analysis of monocular motion picture and also calculates the averages of frame depth and relative depth of region to the average depth. Simulation results show that the depth of region belongs to a near object or a distant object is in accord with relative depth that human visual system recognizes.

• Steel and Composite Structures
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• v.14 no.3
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• pp.295-312
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• 2013

In this paper, a simplified approach based on critical temperature for fire resistance design of steel-concrete composite beams is proposed. The method for determining the critical temperature and fire protection of the composite beams is developed on the basis of load-bearing limit state method employed in current Chinese Technical Code for Fire safety of Steel Structure in Buildings. Parameters affecting the critical temperature of the composite beams are analysed. The results show that at a definite load level, section shape of steel beams, material properties, effective width of concrete slab and concrete property model have little influence on the critical temperature of composite beams. However, the fire duration and depth of concrete slab have significant influence on the critical temperature. The critical temperatures for commonly used composite beams, at various depth of concrete and fire duration, are given to provide a reference for engineers. The validity of the practical approach for predicting the critical temperature of the composite beams is conducted by comparing the prediction of a composite beam with the results from some fire design codes and full scale fire resistance tests on the composite beam.

• Transactions of Materials Processing
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• v.22 no.5
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• pp.264-268
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• 2013

Aluminum clad sheets for brazing materials in the automotive heat exchangers are required to exhibit both high strength and excellent erosion resistance. In this study, the effects of microstructural changes on the property of clad sheets due to thermomechanical treatment were investigated. The clad sheets were fabricated by roll bonding of twin-roll-cast AA3527 and AA4343 alloys followed by cold rolling down to a thickness of 0.22mm. Partial or full annealing was conducted at the final thickness in order to improved the erosion resistance while keeping the proper strength. Since full annealing was achieved for a temperature of $400^{\circ}C$, annealing treatments were performed at 360, 380, and $400^{\circ}C$, respectively. The tensile strength of 3527/4343 clad material was found to be inversely proportional to the annealing temperature before the brazing heat treatment. After this latter treatment, however, the tensile strength of the clad material was about 195~200MPa regardless of the annealing temperature. The erosion depth ratio of the clad annealed at $400^{\circ}C$ was 8.8% (the lowest), while that of the clad annealed at $380^{\circ}C$ was 17% (the highest). The effect of annealing temperature on the tensile and erosion properties of 3527/4343 aluminum clad sheets was elucidated by means of microstructural analyses.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• v.5 no.5
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• pp.583-591
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• 2018

Tool-chip adhesion impacts on cutting performance significantly, especially in finish cutting process. To promote cutting tools' anti-adhesion property, the concave micro-grooves texture (MGT) and convex volcano-like texture (VLT) were fabricated separately on lathe tools' rake faces by laser surface texturing (LST). Various orientations of MGT and different area densities (9% and 48%) and regions (partial and full) of VLT were considered in textured patterns designing. The following orthogonal cutting experiments, machining of aluminum alloy 5038, analyzed tools' performances including cutting force, cutting stability, chip shape, rake face adhesion and abrasion. It indicated that under dry finish cutting conditions, MGT contributed to cutting stability and low cutting forces, meanwhile friction and normal force reduced by around 15% and 10%, respectively with a weak correlation to the grooves' orientation. High density VLT tools, on the other hand, presented an obvious anti-adhesion property. A $5{\mu}m$ reduction of crater wear's depth can be observed on textured rake faces after long length cutting and textured rake faces presented half size of BUE regions comparing to the flat tool, however, once the texture morphologies were filled or worn, the anti-adhesion effect could be invalid. The bearing ratio curve was employed to analysis tool-chip contact and durability of textured surfaces contributing to a better understanding of anti-adhesion and enhanced durability of the textured tools.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.3-11
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• 2016

The concern about hollow core PC slab has been increased to improve the workability during a construction of building by reducing self weight of structural members. In this manner, recently, TRS (Tripple Ribs Slab) was developed as a new type of half PC slab system. TRS member consists of the triple webs and the bottom flange prestressed by strands. The slab system is completed by casting of topping concrete on the TRS after filling styrofoam between the webs. This paper, presents a flexural experiment to investigate the flexural capacity of the TRS. Five full scale TRS members were made and tested under simple support condition to be failed by flexure and their strength was evaluated by code equations; the variables in the test are the depth and the presence of topping or raised spot formed when slip-forming. In addition, a nonlinear sectional analysis was performed for the specimens and the result was compared with the test results. From the study, it was found that the TRS has enough flexural strength and ductility to resist the design loads and its strength can be suitably predicted by using code equations. The raised spot did not affect the strength so that the spot need not to be removed by doing additional work. For the more accurate prediction of TRS's flexural behavior by using nonlinear sectional analysis, it is recommended to consider the concrete's brittle property due to slip-forming process in the modeling.

• Journal of Soil and Groundwater Environment
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• v.12 no.3
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• pp.10-16
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• 2007

The slug test by adding water to well and measuring falling head was conducted to investigate the hydrogeological property of unsaturated or partially saturated mine tailings in the Imgi abandoned mine in Busan. In case that wells were installed with a full screen through two layers with different hydraulic properties, Bouwer and Rice method was useful to estimate the hydraulic conductivity and the depth of mine tailings. In particular, when groundwater dried out in the dry season, the slug test performed by adding water into well to form artificial water table and then conducting falling head test produced the reasonable hydraulic conductivity values. The slug test using falling head test can be an alternative to investigate the hydrogeological property of abandoned mine tailings.