• Structural Engineering and Mechanics
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• v.27 no.5
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• pp.575-588
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• 2007

In this paper, two algorithms are presented for the optimum design of geometrically nonlinear steel space frames using tabu search. The first algorithm utilizes the features of short-term memory (tabu list) facility and aspiration criteria and the other has long-term memory (back-tracking) facility in addition to the aforementioned features. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Allowable stress design (ASD) specification, maximum drift (lateral displacement) and interstorey drift constraints were imposed on the frames. The algorithms were applied to the optimum design of three space frame structures. The designs obtained using the two algorithms were compared to each other. The comparisons showed that the second algorithm resulted in lighter frames.

• Steel and Composite Structures
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• v.19 no.4
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• pp.1035-1053
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• 2015

A genetic algorithm-based minimum weight design method is presented for steel frames containing composite beams, semi-rigid connections and column bases. Genetic Algorithms carry out optimum steel frames by selecting suitable profile sections from a specified list including 128 W sections taken from American Institute of Steel Construction (AISC). The displacement and stress constraints obeying AISC Allowable Stress Design (ASD) specification and geometric (size) constraints are incorporated in the optimization process. Optimum designs of three different plane frames with semi-rigid beam-to-column and column-to-base plate connections are carried out first without considering concrete slab effects on floor beams in finite element analyses. The same optimization procedures are then repeated for the case of frames with composite beams. A program is coded in MATLAB for all optimization procedures. Results obtained from the examples show the applicability and robustness of the method. Moreover, it is proved that consideration of the contribution of concrete on the behavior of the floor beams enables a lighter and more economical design for steel frames with semi-rigid connections and column bases.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.751-754
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• 2000

In this paper, we propose an efficient method to detect abrupt shot changes in compressed MPEG video data by using reference ratios among video frames. The reference ratios among video frames imply the degree of similarities among adjacent frames by prediction coded type of each frames. A shot change is detected if the similarity degrees of a frame and its adjacent frames are low. This paper proposes an efficient shot change detection algorithm by using Fuzzy c-means(FCM) clustering algorithm. The FCM clustering uses the shot change probabilities evaluated in the mask matching of reference ratios and difference measure values based on frame reference ratios.

• Journal of Korean Society of Steel Construction
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• v.8 no.4 s.29
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• pp.121-131
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• 1996

Semi-rigid frames are frames for whcih the connections joining the beam and column are neither fully rigid nor perfectly pinned. In reality, all steel frames are semi-rigid in nature as all connections exhibit a certain degree of flexibility under loads. For semi-rigid frmaed structures, it is tended to reduce more rigidity of the member for the nonlinear behavior of connections and the P-delta effects of framed structure. To predict the actual behavior of semi-rigid steel frames, a more realistic analysis methods which explicitly takes into account the effect of connection flexibility should be used. In this research, the effect of connection flexibility in the semi-rigid structure has been investigated. To predict the response of flexibility connected frames, the algorithm of semi-rigid steel frame is developed using connection model having nonlinear spring on end of beam.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.793-806
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• 2016

G-vector-valued sequence space frames and g-Banach frames for Banach spaces are introduced and studied in this paper. Also, the concepts of duality mapping and ${\beta}$-dual of a BK-space are used to define frame mapping and synthesis operator of these frames, respectively. Finally, some results regarding the existence of g-vector-valued sequence space frames and g-Banach frames are obtained. In particular, it is proved that if X is a separable Banach space and Y is a Banach space with a Schauder basis, then there exist a Y-valued sequence space $Y_v$ and a g-Banach frame for X with respect to Y and $Y_v$.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.231-234
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• 2005

Steel braced frames retrofit method has been broadly used due to their effectiveness in both light weight and construction periods. However, steel braced frames retrofit method has difficulties in application on the inner frames of buildings to be retrofitted consequently, there have been demands for the braced frames retrofit method that can be broadly and easily applicable to both inner and outer frames of the buildings. The objective of this study is to develop and evaluate the seismic retrofit method applicable to the inner frame also by dividing the reinforcing frames into three unit. From the cyclic test of specimens, the test results dearly showed that steel brace using HPFRCCs and steel bars ensure the better cyclic compressive performance than the normal braced members.

• Steel and Composite Structures
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• v.5 no.5
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• pp.407-420
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• 2005

This study presents the strength of braced and unbraced cold-formed steel wall frames consisting of several wall studs acting as columns, top and bottom tracks, and bracing members. The strength and the buckling mode of steel wall frames were found to be different due to the change of bracing type. In addition, the spacing of wall studs is a crucial factor to the strength of steel wall frames. The comparisons were made between the test results and the predictions computed based on AISI Code. The related specifications do not clearly provides the effective length factors for the member of cold-formed steel frame under compression. This paper proposes effective length factors for the steel wall frames based on the test results. A theoretical model is also derived to obtain the modulus of elastic support provided by the bracing at mid-height of steel wall frames in this research.

• Steel and Composite Structures
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• v.25 no.1
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• pp.1-17
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• 2017

Seismic performance of hybrid steel frames defined as mixture of rigid and semi-rigid connections is investigated in this paper. Three frames with 10, 15 and 20 stories are designed with fully rigid connections and then with 4 patterns for semi-rigid connection placement, some of beam to column rigid connections would turn to semi-rigid. Each semi-rigid connection is considered with 4 different moment capacities and all rigid and semi-rigid frames consisting of 51 models are subjected to 5 selected earthquake records for nonlinear analysis. Maximum story drifts, roof acceleration and base shear are extracted for those 5 earthquake records and average values are obtained for each case. Based on numerical results for the proposed hybrid frames, story drifts remain in allowable range and the reductions in the maximum roof acceleration of 22, 29 and 25% and maximum base shear of 33, 31 and 54% occur in those 10, 15 and 20-story frames, respectively.

• Journal of the Korean Mathematical Society
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• v.53 no.6
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• pp.1331-1345
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• 2016

A K-g-frame is a generalization of a g-frame. It can be used to reconstruct elements from the range of a bounded linear operator K in Hilbert spaces. K-g-frames have a certain advantage compared with g-frames in practical applications. In this paper, the interchangeability of two g-Bessel sequences with respect to a K-g-frame, which is different from a g-frame, is discussed. Several construction methods of K-g-frames are also proposed. Finally, by means of the methods and techniques in frame theory, several results of the stability of K-g-frames are obtained.

• Advances in concrete construction
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• v.4 no.1
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• pp.37-47
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• 2016

The objective of the present work is to evaluate the influence of two different methods of improving the ductility of Reinforced Concrete Frames and their influence on the full range behavior of the frames with M40 grade of concrete. For this purpose one fourth scale reinforced concrete square frames are experimentally tested subjected to static cyclic loading for three cases and monotonic loading for one case. The parameters are varied as method introducing ductility to the frame viz. (i) by using conventional concrete (ii) adding 1% of steel fibres by volume of concrete at hinging zones (iii) using self-compacting concrete with fibres at hinging zones. The energy absorption by ductile and non-ductile frames has been compared. The behavior of frames tested under cyclic loading have revealed that there is a positive trend in improvement of ductility of frames when fibrous concrete is used along with self-compacting concrete.