• Journal of Adhesion and Interface
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• 제5권2호
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• pp.14-26
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• 2004

For reliable determination of mechanical characteristics of adhesively bonded joints used e.g. as input data for computer-aided design of complex components, the thick-adherend tensile-shear test according to ISO 11003-2 is the most important material testing method. Although the total displacement of the joint is measured across the polymer layer directly in the overlap zone in order to minimize the influence of the stepped adherends, the substrate deformation must be taken into account within the framework of the evaluation of the shear modulus and the maximum shear strain, at least when high-strength adhesives are applied. In the standard ISO 11003-2 version of 1993, it was prescribed to perform the substrate deformation correction by means of testing a one-piece reference specimen. The authors, however, pointed to the excessive demands on the measuring accuracy of the extensometers connected with this technique in industrial practice and alternatively proposed a numerical deformation analysis of a dummy specimen. This idea of a mathematical correction was included in the revised ISO 11003-2 version of 2001 but in the simplified form of an analytical method based on Hooke's law of elasticity for small strains. In the present work, it is shown that both calculation techniques yield considerably discordant results. As experimental assessment would require high-precision distance determination (e.g. laser extensometer), finite element analyses of the deformation behavior of the bonded joint are performed in order to estimate the accuracy of the obtained substrate deformation corrections. These simulations reveal that the numerical correction technique based on the finite element deformation modeling of the reference specimen leads to considerably more realistic results.

• Journal of The Korean Association For Science Education
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• 제33권2호
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• pp.359-372
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• 2013

This study aims to investigate the current status of science museum in terms of evaluating its organization, management, and education program. The analytical framework developed for examination are as follows: First, the lack of professional staff in most target museums is the biggest impediment for domestic science museums to function properly. Second, funding has been very poor. Third, most museums failed to properly sustain exhibits, equipment, and facilities. Fourth, various advertising and marketing efforts for attracting more visitors are hardly done. And lastly, the domestic museums made little effort in pursuing research focusing on improving exhibitions and education program. Based on these findings, the future directions for domestic science museums to step-up opportunities have been discussed in this study.

• Journal of Digital Convergence
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• 제8권2호
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• pp.203-216
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• 2010

This study corresponds to an exploratory survey that identifies and organizes important decision factors for establishing R&D strategic portfolio in the application of digitalized Korean human-dataset. In the case of countries that have performed the above, the digitalized human-dataset and its visualization application development research are regarded as strategic R&D projects selected and supervised in national level. To achieve the goal of this study, we organize a professional group that reviews articles, suggests research topics, considers alternatives and answers questionnaires. With this study, we draw and refine the detailed factors; these are reflected during a strategic planning phase that includes R&D vision setting, SWOT analysis and strategy development, research area and project selection. In addition to this contribution for supporting the strategic planning, the study also shows the detailed research area's definition/scope and their priorities in terms of importance and urgency. This addition will act as a guideline for investigating further research and as a framework for assessing the current status of research investment.

• ETRI Journal
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• 제37권3호
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• pp.450-459
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• 2015

Small cell networks, as an important evolution path for next-generation cellular networks, have drawn much attention. Different from the traditional base stations (BSs) always-on model, we proposed a BSs on-off model, where a new, simple expression for the probabilities of active BSs in a heterogeneous network is derived. This model is more suitable for application in practical networks. Based on this, we develop an analytical framework for the performance evaluation of small cell networks, adopting stochastic geometry theory. We derive the system coverage probability; average energy efficiency (AEE) and average uplink power consumption (AUPC) for different association strategies; maximum biased received power (MaBRP); and minimum association distance (MiAD). It is analytically shown that MaBRP is beneficial for coverage but will have some loss in energy saving. On the contrary, MiAD is not advocated from the point of coverage but is more energy efficient. The simulation results show that the use of range expansion in MaBRP helps to save energy but that this is not so in MiAD. Furthermore, we can achieve an optimal AEE by establishing an appropriate density of small cells.

• Spatial Information Research
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• 제9권2호
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• pp.185-206
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• 2001

Cellular Automata(CA) have been investigated and utilized as a theoretical framework and/or methodology for analyzing and simulating the properties and behaviors of many complex systems in various physical science and engineering field. Due to the conceptual elegance and effectiveness of implementing spatio-temporal dynamic models and the compatibility with raster GISs, recently a variety of modeling works using both CA and GIS have been published in GIS fields Most of spatial dynamic models introduced in previous research, however, were very limited and furthermore integrated CA-GIS system for practical modeling purpose are not developed yet. This study aims to develop an integrated CA-GIS system in which a CA simulator is used as an analytical engine for GIS providing a multipurpose spatial dynamic modeling functionalities. This integrated CA-GIS system is anticipated radically enhancing the current lacking dynamic modeling functionalities of GIS and being utilized as an powerful and effective tool for practical spatial dynamic modeling research.

• Spatial Information Research
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• 제20권5호
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• pp.15-24
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• 2012

The purpose of this study was to establish an analytical framework and quantitative methodologies to analyze 'the cognitive effects of web map use' and to empirically test it. This experimental design was established based on the literature about spatial cognition. Accuracy, reaction time, and confidence within each participant were compared to measure the cognitive effects of web map use for wayfinding. Geometric accuracy of the cognitive maps was estimated and calculated based on the bidimensional regression. The experimental results showed that characteristics of map users and repetition of map use rather than types of map representation did significantly affect accuracy and reaction time of spatial cognition by using web maps. And confidence appeared to be low when the participants referred to both 2D and 3D maps for wayfinding tasks on the web maps. Understanding spatial cognition of web map users, which was suggested in the study, will help cartographers make more effectively-communicated maps.

• Advances in aircraft and spacecraft science
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• 제1권2호
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• pp.197-218
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• 2014

Quite a demanding task frequently arises in space engineering, when dealing with the cargo accommodation of modules and vehicles. The objective of this effort usually aims at maximizing the loaded cargo, or, at least, at meeting the logistic requirements posed by the space agencies. Complex accommodation rules are supposed to be taken into account, in compliance with strict balancing conditions and very tight operational restrictions. The context of the International Space Station (ISS) has paved the way for a relevant research and development activity, providing the company with a remarkable expertise in the field. CAST (Cargo Accommodation Support Tool) is a dedicated in-house software package (funded by the European Space Agency, ESA, and achieved by Thales Alenia Space), to carry out the whole loading of the Automated Transfer Vehicle (ATV). An ad hoc version, tailored to the Columbus (ISS attached laboratory) on-board stowage issue, has been further implemented and is to be used from now on. This article surveys the overall approach followed, highlighting the advantages of the methodology put forward, both in terms of solution quality and time saving, through an overview of the outcomes obtained to date. Insights on possible extensions to further space applications, especially in the perspective of the paramount challenges of the near future, are, in addition, presented.

• Smart Structures and Systems
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• 제12권5호
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• pp.501-521
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• 2013

This paper is concerned with static and dynamic shape control of a laminated Bernoulli-Euler beam hosting a uniformly distributed array of resistively interconnected piezoelectric patches. We present an analytical one-dimensional model for a laminated piezoelectric beam with material discontinuities within the framework of Bernoulli-Euler and extent the model by a network of resistors which are connected to several piezoelectric patch actuators. The voltage of only one piezoelectric patch is prescribed: we answer the question how to design the interconnected resistive electric network in order to annihilate lateral vibrations of a cantilever. As a practical example, a cantilever with eight patch actuators under the influence of a tip-force is studied. It is found that the deflection at eight arbitrary points along the beam axis may be controlled independently, if the local action of the piezoelectric patches is equal in magnitude, but opposite in sign, to the external load. This is achieved by the proper design of the resistive network and a suitable choice of the input voltage signal. The validity of our method is exact in the static case for a Bernoulli-Euler beam, but it also gives satisfactory results at higher frequencies and for transient excitations. As long as a certain non-dimensional parameter, involving the number of the piezoelectric patches, the sum of the resistances in the electric network and the excitation frequency, is small, the proposed shape control method is approximately fulfilled for dynamic load excitations. We evaluate the feasibility of the proposed shape control method with a more refined model, by comparing the results of our one-dimensional calculations based on the extended Bernoulli-Euler equations to three-dimensional electromechanically coupled finite element results in ANSYS 12.0. The results with the simple Bernoulli-Euler model agree well with the three-dimensional finite element results.

• Journal of the Korean School Mathematics Society
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• 제22권4호
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• pp.351-367
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• 2019

Slope is an important mathematical concept that is connected to advanced mathematics as well as a basic concept as an indicator of the steepness of a straight line. The purpose of this study is to see how the concept of slope is presented in mathematics textbooks of middle school. For this study, we analyzed the types of slope concepts in the textbooks. In particular, we analyzed motivation activity, definition, examples of slope in them and used a concept framework of slope by Stump(1999, 2001), Moore-Russo, Connor & Rugg (2011). As a result, it was shown that middle school mathematics textbooks use the types of slope concepts to be biased when explaining the slope or presenting the slope problems. In addition, the real contexts of slope is poorly presented, and the concept types change from visual aspect to analytical aspect in the processes. This study provides suggestions on how to present the slope concepts in mathematics curriculum and middle school textbooks.

• Journal of Digital Convergence
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• 제16권7호
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• pp.409-418
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• 2018

This study aims to find improvements to problems including investigation public affairs for the activities of artists focusing on the Korean Artists Welfare Foundation since established in 2012. Hence, Gilbert and Terrell's analytical framework for social policy is used with these public affairs in terms of allocation, benefit, service delivery system and finance for this research and pointed at issue. As a result of analysis, the identification of artist is vague for the allocation and the benefit and delivery are not effective in actual practice. In addition to this, the source of fund should become independent financially not to depend on the public funding. Therefore, the follow-up research is necessary that the system of verification for the artists to benefit from the public supports with fair and effective opportunities and developments to secures the funds prospectively.