• Proceedings of the KSME Conference
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• 2008.11a
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• pp.138-143
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• 2008

Recently, a new periodic cellular metal(PCM) named as Wire wove Bulk Kagome(WBK) was introduced. Based on the shape of tetrahedra composing a WBK, WBKs are classified into two types, namely, concave and convex type. They are easily differentiated by changing the assembling sequence. The effect of geometrical parameters such as the wire diameter, strut length and number of layers on the compressive behavior of concave type WBK has already been investigated. In this work, the similar works were performed with the convex type WBKs. It was shown that the compressive strength of the convex type WBK was quite similar to that of the concave type. The compressive strengths of convex type specimens also depend on the slenderness ratio, but a little different from those of concave type specimens in the detailed behavior. And densification occurs earlier than the concave type WBK.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.227-236
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• 1994

The purpose of this study was to observe mandibular condyle shape in an asymptomatic population. In order to carry out this study, 96 temporomandibular joints in 48 adults(22 males, 26 females), who were asymptomatic for temporomandibular disturbances and had no history of prosthodontic or orthodontic treatments, were selected, and radiographed using the Sectograph(Denar Co., U.S.A.) for lateral and frontal individualized corrected TMJ tomograph and submentovertex radiograph. Mandibular condyles were classified morphologically, and measured medioateral and anteroposterior dimensions and condylar angulation. The obtained results were as follows. 1. In the classification of condyle shape on lateral tomographs, 94.8% were convex type and 5.2% were angled type. 2. In the classification of condyle shape on frontal tomographs, 45.3% were convex type, 32.0% were round type, 16.0% were flat type, and 6.7% were angled type. 3. In the classification of condyle shape on submentovertex radiographs, 34.5% were flat-convex type, 22.9% were flat-flat type, 20.8% were concave-convex type, 19.8% were convex-convex type, and 1.0% were concave-flat type and convex-flat type. Concave-concave type, convex-concave type, and flat-concave type were not observed. 4. The average mediolateral legth of the condyle was 19.3㎜ and the average anteroposterior length was 9.4㎜. The average angle between the long axis of condyle and the coronal plane made on submentovertex view was 19.6 degrees.

• Corrosion Science and Technology
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• v.2 no.5
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• pp.243-246
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• 2003

We have used a plasma etching method in order to develop a concave-type Pt electrode capacitor to overcome the limitation of conventional stack-type capacitor in a small critical-dimension (CD) pattern. We have deposited Pt layer on the concave-type structure made by patterning of $SiO_2$ and subsequently we separated the adjacent nodes by etch-back process with photoresist (PR) as a protecting layer.

• International Journal of Computer Science & Network Security
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• v.24 no.1
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• pp.85-94
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• 2024

In this paper, we present the very first time the generalized notion of (α, β, γ, δ) - convex (concave) function in mixed kind, which is the generalization of (α, β) - convex (concave) functions in 1^st and 2^nd kind, (s, r) - convex (concave) functions in mixed kind, s - convex (concave) functions in 1^st and 2^nd kind, p - convex (concave) functions, quasi convex(concave) functions and the class of convex (concave) functions. We would like to state the well-known Ostrowski inequality via SVN-Riemann Integrals for (α, β, γ, δ) - convex (concave) function in mixed kind. Moreover we establish some SVN-Ostrowski type inequalities for the class of functions whose derivatives in absolute values at certain powers are (α, β, γ, δ)-convex (concave) functions in mixed kind by using different techniques including Hölder's inequality and power mean inequality. Also, various established results would be captured as special cases with respect to convexity of function.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1155-1162
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• 2012

The purpose of this study is to investigate the effects of the bead shape on the crash performance of an aluminum crash box under a low-velocity impact condition. The initial peak load and impact energy absorption of a crash box with three types of bead shapes-edge concave, surface convex, and surface concave type-were studied through an FE analysis and an experiment. In addition, the effects of the bead shapes on the crash performance of the crash box were verified through a low-velocity-impact test with a front side member assembled with an aluminum crash box. The initial peak load of the surface-concave-type crash box was reduced by the bead, and therefore, deformation of the front side member at initial contact could be prevented. Furthermore, there was no deformation of the front side member after the impact test because the crash box with a surface-concave-type bead absorbed all the impact energy.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.50-56
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• 2004

This study was conducted to investigate the performance of sound absorption type-noise barriers manufactured with a combination of wood particles used for particleboard, recycled waste newspaper, and cement. An average density of wood-combined cement board was in the range from 0.83 to 0.96 g/cm³, showing relatively low-density board. Regardless of types of cement bonded board or wooden board, the board with concave holes(凹)-formed surfaces showed greater sound absorption coefficient compared to those of flat surface boards. The board density was not related with those coefficients. Accordingly, it was concluded that concave or deep corrugated surface structure has played an important role in sound absorption for the application of sound absorption type-noise barrier.

• Structural Engineering and Mechanics
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• v.40 no.3
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• pp.315-334
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• 2011

Seismic isolated building structures are examined in this study. The triple concave friction pendulum (TCFP) is used as a seismic isolation system which is easy to be manufactured and enduring more than traditional seismic isolation systems. In the TCFP, take advantage of weight which pendulum carrying and it's geometry in order to obtain desirable result of seismic isolation systems. These systems offer advantage to buildings which subject to severe earthquake. This is result of damping force of earthquake by means of their internal constructions, which consists of multiple surfaces. As the combinations of surfaces upon which sliding is occurring change, the stiffness and effective friction change accordingly. Additionally, the mentioned the TCFP is modeled as of a series arrangement of the three single concave friction pendulum (SCFP) bearings. A two dimensional- and eight- story of a building with and without isolation system are used in the time history analysis in order to investigate of the effectiveness of the seismic isolation systems on the buildings. Results are compared with each other to emphasize efficiency of the TCFP as a seismic isolation device against the other friction type isolation system like single and double concave surfaces. The values of the acceleration, floor displacement and isolator displacement obtained from the results by using different types of the isolation bearings are compared each other. As a result, the findings show that the TCFP bearings are more effective devices for isolation of the buildings against severe earthquakes.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1507-1518
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• 2010

In this article some generalized refinements of some inequalities for real quasi-cinvex, convex, concave, s-convex, s-concave, and $\alpha$-star s-convex mappings are obtained.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.239-242
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• 2016

In this paper, we proposed the dual curved lens of concave type. HDPE (High Density Polyethylene) used to fabricate the dual curved lens. The dual curved lens consisted of two concave structures. Role of two concave structures is to beam uniform and expansion. A small concave structure has the greater curvature than big concave structure. The dual curved lens will apply to millimeter imaging system. We measured the dual curved lens performance using 250 GHz VDI source. And we simulated the dual curved lens using ZEMAX. Fabricated lens have a good performance for beam uniform and expansion.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.2
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• pp.3-13
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• 1993

In this study, we develop a B & B type algorithm for the concave minimization problem with 0-1 knapsack constraint. Our algorithm reformulates the original problem into the singly linearly constrained concave minimization problem by relaxing 0-1 integer constraint in order to get a lower bound. But this relaxed problem is the concave minimization problem known as NP-hard. Thus the linear function that underestimates the concave objective function over the given domain set is introduced. The introduction of this function bears the following important meanings. Firstly, we can efficiently calculate the lower bound of the optimal object value using the conventional convex optimization methods. Secondly, the above linear function like the concave objective function generates the vertices of the relaxed solution set of the subproblem, which is used to update the upper bound. The fact that the linear underestimating function is uniquely determined over a given simplex enables us to fix underestimating function by considering the simplex containing the relaxed solution set. The initial containing simplex that is the intersection of the linear constraint and the nonnegative orthant is sequentially partitioned into the subsimplices which are related to subproblems.