• Composites Research
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• v.17 no.1
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• pp.38-46
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• 2004

This paper aims to correlate the micro-mechanical behaviour of tow geometry with applied in-plane forces during deformation of dry woven carbon-fibre fabric. These in-plane forces lead to differences in tow reorganisation during deformation and so changes in the way in which 'lock-up' occurs. In this paper, deformation of micro-mechanical parameters such as tow interval, crimp angle, change in tow amplitude and wavelength are investigated. To observe the micro-deformation of the fabric structure, appropriate specimens from bias extension and biaxial tests are sectioned and observed under the microscope. It was found that different loading conditions cause geometric deferences in the tow architecture. The variation in deformed tow geometry with shear angle is fitted using a simple parametric model.

• Journal of Technology Innovation
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• v.15 no.2
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• pp.61-81
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• 2007

A typical small firm in consumer goods sectors of developing countries is an OEM supplier to big MNCs. Lacking design and marketing capability, a small firm relies on the MNCs for survival but their long term growth is not guaranteed as the MNCs are always looking for, and ready to relocate to, cheaper production sites. In this light, we can say that there is something like "OEM trap" from which most firms from LDCs find difficult to move out (Lee 2005). In this situation, one way for long term growth and catch-up is to make a transition to the OBM (own brand manufacturer). But, the transition is not easy or even risky. This paper analyzes the cases of three companies in Korea to find out common features in their successful transition to OBM. They are Aurora World (a flush toy maker), Hankook Chinaware (a chinaware maker), and Hanacobi (a plastic-made food container maker with the Lock-and-Lock brand). These firms can be commonly characterized by 1) arranging access to external knowledge base and steady increase of in-house R&D efforts and capabilities leading to acquisition of formal IPRs and their management, and 2) establishment of global production networks with factories in lower-income countries as well as their own independent global marketing network.

• Asia pacific journal of information systems
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• v.23 no.1
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• pp.21-43
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• 2013

Internet vendors are gradually realizing the importance of "locking-in" online customers in order to ensure profitability. Erection of switching barriers increases customers'lock-in and in turn may result in their willingness to pay price-premium for the same service. However, raising customer lock-in online is difficult because search costs are very low. Therefore, this study examines the effect of switching barriers (customer satisfaction, perceived value and relative advantage) on switching costs and the effect of switching costs on customer's willingness to pay more. Since switching costs and consequent relationships may depend upon the type of product therefore the research model in this study is examined for both search products and experience products. Data is collected through an online survey from two websites (one each for search product and experience product). The empirical results show the key role of switching costs in customers' willingness to pay more and the relationships among the four constructs. The theoretical and practical implications of this study are also discussed.

• Journal of Information Processing Systems
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• v.14 no.2
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• pp.499-509
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• 2018

Recently, hybrid transactional memory (HyTM) has gained much interest from researchers because it combines the advantages of hardware transactional memory (HTM) and software transactional memory (STM). To provide the concurrency control of transactions, the existing HyTM-based studies use a bloom filter. However, they fail to overcome the typical false positive errors of a bloom filter. Though the existing studies use a global lock, the efficiency of global lock-based memory allocation is significantly low in multi-core environment. In this paper, we propose an efficient hybrid transactional memory scheme using near-optimal retry computation and sophisticated memory management in order to efficiently process transactions in multi-core environment. First, we propose a near-optimal retry computation algorithm that provides an efficient HTM configuration using machine learning algorithms, according to the characteristic of a given workload. Second, we provide an efficient concurrency control for transactions in different environments by using a sophisticated bloom filter. Third, we propose a memory management scheme being optimized for the CPU cache line, in order to provide a fast transaction processing. Finally, it is shown from our performance evaluation that our HyTM scheme achieves up to 2.5 times better performance by using the Stanford transactional applications for multi-processing (STAMP) benchmarks than the state-of-the-art algorithms.

• Journal of Ocean Engineering and Technology
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• v.16 no.5
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• pp.15-20
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• 2002

In this research, the finite difference lattice Boltzmann method(FDLBM) is used to analyze gravity currents in the lock exchange configuration that occur in many natural and man-made situations. At a lock those are seen when a gate is suddenly opened, and, in the atmosphere, when the thunderstorm outflows make a cold front. At estuaries in the ocean, the phenomenon is found between fresh water from a river and salt water in the sea. Since such interesting phenomena were recognized, pioneers have challenged to make them clear by conducing both experiments and analysis. Most of them were about the currents of liquid or Boussinesq fluids, which are assumed as incompressible. Otherwise, the difference in density of two fluids is small. The finite difference lattice Boltzmann method has been a powerful tool to simulate the flow of compressible fluids. Also, numerical predictions using FDLBM to clarify the gravity currents of compressible fluids exhibit all features, but typically observed in experimental flows near the gravity current head, including the lobe-and-cleft structure at the leading edge.

• Wind and Structures
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• v.32 no.4
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• pp.309-319
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• 2021

The vortex-drift pattern over a girder surface, actually demonstrating the complex fluid-structure interactions between the structure and surrounding flow, is strongly correlated with the VIVs but has still not been elucidated and may be useful for modeling VIVs. The complex fluid-structure interactions between the structure and surrounding flow are considerably simplified in constructing a vortex model to describe the vortex-drift pattern characterized by the ratio of the vortex-drift velocity to the oncoming flow velocity, considering the aerodynamic work. A spring-suspended sectional model (SSSM) is used to measure the pressure in wind tunnel tests, and the aerodynamic parameters for a typical streamlined closed-box girder are obtained from the spatial distribution of the phase lags between the distributed aerodynamic forces at each pressure point and the vortex-excited forces (VEFs). The results show that the ratio of the vortex-drift velocity to the oncoming flow velocity is inversely proportional to the vibration amplitude in the lock-in region and therefore attributed to the "lock-in" phenomena of the VIVs. Installing spoilers on handrails can destroy the regular vortex-drift pattern along the girder surface and thus suppress vertical VIVs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.823-824
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• 2012

• The Journal of the Acoustical Society of Korea
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• v.13 no.6
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• pp.24-30
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• 1994

In this paper, the system for detection of photoacoustic signal has been constructed by using CW $CO_{2}$ laser for an analysis of the photoacoustic signal In metals and aluminum carbon steel, brass have been used as sample. The photoacoustic signals of several nano amperes have been detected in each sample with varying modulation frequency of laser, time constant of lock-in amplifier, thickness of sample. The characteristics of photoacoustic signal has been analysed in term of phase angle by using signal processing technique. Results indicate that the photoacoustic signal can be stabilized by adjustment of time constant of lock-in amplifier, that the signal amplitude is proportional to the ratio of thermal expansion coefficient to thermal capacity of metal, and that the signal amplitude decreases exponentially with sample thickness as well as with modulation frequency.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.3
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• pp.206-214
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• 2015

In this study, low-velocity impact damage (LVID) in glass fiber reinforced plastic (GFRP) was investigated using pulse thermography (PT) and lock-in thermography (LIT) techniques. The main objective of this study was to evaluate the detection performance of each technique for LVID in GFRP. Unidirectional and cross-ply GFRPs were prepared with four energy levels using a drop weight impact machine and they were inspected from the impact side, which may be common in actual service conditions. When the impacted side was used for both inspection and thermal loading, results showed that the suggested techniques were able to identify the LVID which is barely visible to the naked eye. However, they also include limitations that depend on the GFRP thickness at the location of the delamination produced by the lowest impact energy of five joule.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.48-53
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• 2005

This paper aims to compare open source software (OSS) with proprietary software (PS), and to propose a new business model for OSS. Generally speaking, PS has made negative impact on software industry in various ways. In contrast, OSS may reduce negative aspects of lock-in effect and transaction cost the ways in which software distribution has been utilized. In this regard, OSS makes it possible to create a new business model, which is software customization. Software customization is not to sell software license directly to end-users, but to create values by means of developing and capitalizing software-related industries where value chain is linked. In other words, the new business model of OSS is focusing on software market where the value created by OSS can be enhanced.