• Computers and Concrete
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• v.17 no.5
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• pp.579-596
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• 2016

This paper describes a method of the refined plastic hinge approach in the framework of the higher-order element formulation that can efficaciously evaluate the limit state capacity of a whole reinforced concrete structural system using least number of element(s), whereas the traditional design of a reinforced concrete structure (i.e. AS3600; Eurocode 2) is member-based approach. Hence, in regard to the material nonlinearities, the efficient and economical cross-section analysis is provided to evaluate the element section capacity of non-uniform and arbitrary concrete section subjected to the interaction effects, which is helpful to formulate the refined plastic hinge method. In regard to the geometric nonlinearities, this paper relies on the higher-order element formulation with element load effect. Eventually, the load redistribution can be considered and make full use of the strength reserved owing to the redundancy of an indeterminate structure. And it is particularly true for the performance-based design of a structure under the extreme loads, while the uncertainty of the extreme load is great that the true behaviour of a whole structural system is important for the economical design approach, which is great superiority over the conservative optimal strength of an individual and isolated member based on traditional design (i.e. AS3600; Eurocode 2).

• Structural Engineering and Mechanics
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• v.38 no.1
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• pp.27-37
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• 2011

This paper presents the results of a study on the capability of nonlinear quasi-static finite element modelling in simulating the hysteretic behaviour of CFRP and GFRP-retrofitted RC exterior beam-column joints under cyclic loads. Four specimens including two plain and two CFRP/GFRP-strengthened beam-column joints tested by Mahini and Ronagh (2004) and other researchers are modelled using ANSYS. Concrete in compression is defined by the modified Hognestad model and anisotropic multi-linear model is employed for modelling the stress-strain relations in reinforcing bars while anisotropic plasticity is considered for the FRP composite. Both concrete and FRP are modelled using solid elements whereas space link elements are used for steel bars considering a perfect bond between materials. A step by step load increment procedure to simulate the cyclic loading regime employed in the testing. An automatically reforming stiffness matrix strategy is used in order to simulate the actual seismic performance of the RC concrete after cracking, steel yielding and concrete crushing during the push and pull loading cycles. The results show that the hysteretic simulation for all specimens is satisfactory and therefore suggest that the numerical model can be used as an inexpensive tool to design of FRP-strengthened RC beam-column joints under cyclic loads.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.185-207
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• 2013

In flexural strength design of normal-strength concrete (NSC) beams, it is commonly accepted that the distribution of concrete stress within the compression zone can be reasonably represented by an equivalent rectangular stress block. The stress block it governed by two parameters, which are normally denoted by ${\alpha}$ and ${\beta}$ to stipulate the width and depth of the stress block. Currently in most of the reinforced concrete (RC) design codes, ${\alpha}$ and ${\beta}$ are usually taken as 0.85 and 0.80 respectively for NSC. Nonetheless, in an experimental study conducted earlier by the authors on NSC columns, it was found that ${\alpha}$ increases significantly with strain gradient, which means that larger concrete stress can be developed in flexure. Consequently, less tension steel will be required for a given design flexural strength, which improves the ductility performance. In this study, the authors' previously proposed strain-gradient-dependent concrete stress block will be adopted to produce a series of design charts showing the maximum design limits of flexural strength and ductility of singly-and doubly-NSC beams. Through the design charts, it can be verified that the consideration of strain gradient effect can improve significantly the flexural strength and ductility design limits of NSC beams.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.247-263
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• 2013

It is evident that torsional resistance of a reinforced concrete (RC) member is attributed to both concrete and steel reinforcement. However, recent structural design codes neglect the contribution of concrete because of cracking. This paper reports on the results of an experimental and numerical investigation into the torsional capacity of concrete beams reinforced only by longitudinal rebars without transverse reinforcement. The experimental investigation involves six specimens tested under pure torsion. Each specimen was made using a cast-in-place concrete with different amounts of longitudinal reinforcements. To create the torsional moment, an eccentric load was applied at the end of the beam whereas the other end was fixed against twist, vertical, and transverse displacement. The experimental results were also compared with the results obtained from the nonlinear finite element analysis performed in ANSYS. The outcomes showed a good agreement between experimental and numerical investigation, indicating the capability of numerical analysis in predicting the torsional capacity of RC beams. Both experimental and numerical results showed a considerable torsional post-cracking resistance in high twist angle in test specimen. This post-cracking resistance is neglected in torsional design of RC members. This strength could be considered in the design of RC members subjected to torsion forces, leading to a more economical and precise design.

• Structural Engineering and Mechanics
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• v.26 no.4
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• pp.409-426
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• 2007

Following previous work carried out in Building Research Institute in Japan, finite element analyses of conceptual column designs are performed in this paper. The effectiveness of the numerical model is evaluated by experimental tests and parametric studies are conducted to determine influential factors in conceptual column designs. First, three different column designs are analysed: bonded, un-bonded, and un-bonded with additional reinforcing bars. The load-displacement curves and cracking patterns in concrete are obtained and compared with experimental ones. The comparisons indicate that the finite element model is able to reflect the experimental results closely. Both numerical and experimental results show that, the introduction of un-bonded zones in a column end can reduce cracking strains, accordingly reduce the stiffness and strength as well; the addition of extra reinforcement in the un-bonded zones can offset the losses of the stiffness and strength. To decide the proper length of the un-bonded zones and the sufficient amount of the additional reinforcing bars, parametric studies are carried out on their influences. It has been found that the stiffness of un-bonded designs slightly decreases with increasing the length of the un-bonded zones and increases with the size of the additional reinforcing bars.

• Knowledge Management Research
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• v.17 no.3
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• pp.161-179
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• 2016

The recent patent wars in the information technology (IT) industry demonstrate the strategic importance of IT patents in the industry. In this paper, we adopt the lens of real options to study the value of IT patents for IT firms. Specifically, we examine the relationship between IT patents and firms' market performance. We also consider the moderating effect of the innovation orientation of firms' patent portfolios (exploitative vs. explorative). Based on a large panel dataset consisting of 697 firms in US IT industries, our results suggest that the impact of IT patents on firm value (as measured by Tobin's q) is positive and significant. Further, we find that this impact varies, depending on the innovation orientation of firms' patent portfolios. IT patent portfolios with higher levels of an exploitative orientation are associated with higher firm value, compared to those with a lower exploitative orientation. This study highlights the value of employing real options theory as the underlying mechanism in understanding the impact of patents on firm valuation. Future researchers can adopt the real options lens to identify and empirically examine the role of other factors that may affect the value of patents and other investments exhibiting real option characteristics. While our paper answers some questions about the value of patents in the IT industry, it also raises a number of additional new questions. As such, we hope that it will generate more research on this important topic.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.301-306
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• 2002

This paper presents the use of the neural network technology to establish a mathematical model for predicting bead geometry (top-bead width, top-bead height, back-bead width and back-bead height) for multi-pass welding, and understand relationships between process parameters and bead geometry for robotic GMA welding process. Using a series of robotic arc welding, additional multi-pass butt welds were carried out in order to verify the performance of the developed neural network model. The results show that not only the proposed model can predict the bead geometry with reasonable accuracy and guarantee the uniform weld quality, but also the neural network model could be better than the linear and curvilin ear equations developed from Lee [8].

• Korean Journal of Veterinary Research
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• v.17 no.2
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• pp.51-61
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• 1977

The smears and tissue sections of organs (liver, lung, kidney, heart, lymph-node, brain) were carried out to compare the detection of parasites in the splenectomized calves artificially infected with B. bigemina and B. argentina, respectively. The results obtained from this experiment were abstracted as follows: 1. In the calves infected with B. argentina the parasites were easily detected by the blood smears and tissue smears but, particularly, the detection of parasites in the kidneys and brain by tissue smears and tissue sections was greater useful. In this experiment, the packing of the parasite-infected red blood cells was found in the capillary vessels of the organs. 2. When the fresh infected-brain was kept at $5^{\circ}C$ refrigerator, Babesia argentina could be detected during 9 days from the brain smears. According to this results, we could do differentiate the parasites from the brain of the dead animal by the doubtful babesiosis in the field. 3. If we use the brain smears and brain sections in order to survey or detect Babesia infections of cattle in Korea, these methods could be worthwhile for the differential diagnosis of B. argentina and B. bigemina.

• Asian Journal of Innovation and Policy
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• v.6 no.3
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• pp.313-331
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• 2017

This paper exhibits the concept of Triple Helix model to explain and link university-industry-government (Triple Helix) connections to national innovation systems theory. The driver of this paper is to test the dynamics of Triple Helix concept under national innovation system in the Association of South East Asian Countries (ASEAN)-5 economies. Panel econometric analysis with cross-sectional dependence (CD) test is applied to investigate the relationship amongst Triple Helix variables. The empirical analysis employs innovation indicators of five founding ASEAN countries namely Malaysia, Indonesia, Singapore, the Philippines and Thailand for the period of 2000-2015 from an existing WDI and WCY database. Econometric results support the two research questions of this study; firstly, there is a significant relationship between innovation outcome and its key drivers under Triple Helix context of National Innovation System in ASEAN-5 economies; secondly, the extent of the relationship among government R&D expenditure with high-tech productions are positive and significant while new ideas coming from universities as scientific publications and high-tech production have positive relationship but not significant yet in ASEAN-5 countries. Overall labor productivity is positive and significant with innovation outcomes in ASEAN-5.

• ETRI Journal
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• v.34 no.1
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• pp.9-16
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• 2012

Precoding in the multiple-input multiple-output orthogonal frequency division multiplexing system is investigated. In conventional wideband precoding (WBP), only one precoder, obtained from the decomposition of the subcarrier independent channel matrix, is used for all subcarriers. With an investigation of the relationship between the subcarrier independent channel matrix and the temporal/frequency channels, an improved WBP scheme is proposed for practical scenarios in which a part of subcarriers are allocated to a user. The improved WBP scheme is a generalized scheme of which narrow-band precoding and conventional WBP schemes are special modes. Simulation results demonstrate that the improved WBP scheme almost achieves the optimum performance of a single precoder and outperforms the conventional WBP scheme in terms of the bit error ratio and ergodic capacity with slight complexity increase. The largest advantage of the improved WBP scheme on signal-to-noise ratio in simulation results is over 2.1 dB.