• Journal of Theoretical and Applied Mechanics
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• v.3 no.1
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• pp.1-15
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• 2002

Reduction methods for large structural systems have been reviewed. Mai emphasis is put on the dynamic reduction. Recently, the computing resources and technologies have been expanded so fast that the huge matrices Invoked In the analysis of structural system can be processed without serious difficulties. For most users, however, the computer facilities are limited and the system reductions in some forms are required. The reduction procedure in static problems is simple and straightforward. The major task is the book-keeping in computations. In dynamic problems and structural optimization. however. the problem is much more complicated. The problem is, in general, nonlinear and hence the exact solution is not available. Therefore, approximate solutions are sought in an iterative manner. A proper convergence criterion needs to be employed in order to get an accurate solution efficiently. Several research works have been reported fer the structural optimization combined with system reductions.

• Korean Journal of Computational Design and Engineering
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• v.15 no.1
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• pp.24-32
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• 2010

This paper introduces a B-spline based branch & bound algorithm for global optimization. The branch & bound is a well-known algorithm paradigm for global optimization, of which key components are the subdivision scheme and the bound calculation scheme. For this, we consider the B-spline hypervolume to approximate an objective function defined in a design space. This model enables us to subdivide the design space, and to compute the upper & lower bound of each subspace where the bound calculation is based on the LHS sampling points. We also describe a search tree to represent the searching process for optimal solution, and explain iteration steps and some conditions necessary to carry out the algorithm. Finally, the performance of the proposed algorithm is examined on some test problems which would cover most difficulties faced in global optimization area. It shows that the proposed algorithm is complete algorithm not using heuristics, provides an approximate global solution within prescribed tolerances, and has the good possibility for large scale NP-hard optimization.

• Electronics and Telecommunications Trends
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• v.36 no.1
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• pp.22-31
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• 2021

In this thesis, we examine the development status of autonomous mobility services using various artificial intelligence algorithms and propose a solution by combining edge and cloud computing to overcome technical difficulties. A fully autonomous vehicle with enhanced safety and ethics can be implemented using the proposed solution. In addition, for the future of 2035, we present a new concept that enables two- and three-dimensional movement via cooperation between ecofriendly, low-noise, and modular fully autonomous vehicles. The zero-error autonomous driving system will safely and conveniently transport people, goods, and services without time and space constraints and contribute to the autonomous mobility services that are free from movement in connection with various mobility.

• Asian Oncology Nursing
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• v.11 no.3
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• pp.210-220
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• 2011

Purpose: The aims of this study were to describe and interpret the nature of the experience inherent in the sex life of female breast cancer patients after treatment and understand the meaning behind it. Methods: The participants were 10 female breast cancer patients who were married. Data were collected from March to September 2010. Van Manen's hermeneutic phenomenology was adopted in this qualitative study as a research method. Results: There were 4 essential topics in the participants' experience of sex life; 'Sex life alert' was a result of negative changes in sexual relationships with spouse that they had never experienced before the breast cancer diagnosis; 'Precarious situation for pending divorce' was an experience of deteriorated sex life because of the failure to overcome 'sex life alert'; 'Sublimation of the difficulties by discovering an alternative solution' was an experience of discovering a solution to overcome the 'sex life alert'. 'Leaving it as unsettled' was an experience of a condition in which the participants did not have any intension to resolve the difficulties in sex life due to the lack of appropriate support, thus tried to ignore the challenges faced. Conclusion: This study illustrates the necessity to develop proper nursing intervention on the issues related to sex life among breast cancer patients. Given the fact that the sexual topics are often considered taboo in day to day nursing practice, special attention and efforts need to be given in this area to build up nursing knowledge and evidence-based practice.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.241-263
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• 2013

The purpose of this paper is to investigate high school students' reasoning characteristics in problem solving. To do this, we selected five high school students as participants and presented them some open problems which allow diverse solving approaches, and recorded their problem solving process. Through analyzing their problem solving process relate to their solution, we found the followings: First, students quickly try to calculate without understanding the given problem. Second, students concern whether their solution is right or not rather than consider mathematical warrants for the results of their strategies. Third, students have difficulties to consider more than two conditions at the same time necessary to solve problem. Forth, students are not familiar to use precedence knowledge relate to given tasks. Fifth, students could have difficulties in problem solving because of easy generalization.

• Composites Research
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• v.29 no.5
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• pp.269-275
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• 2016

Multiscale hybrid composites, which consist of polymeric resins, microscale fibers and nanoscale reinforcements, have drawn significant attention in the field of advanced, high-performance materials. Despite their advantages, multiscale hybrid composites show challenges associated with nanomaterial dispersion, viscosity, interfacial bonding and load transfer, and orientation control. In this paper, carbon nanotube(CNT)/carbon fiber(CF)/polycarbonate(PC) multiscale hybrid composite were fabricated by a solution process to overcome the difficulties associated with controlling the melt viscosity of thermoplastic resins. The dependence of CNT loading was studied by varying the method to add CNTs, i.e., impregnation of CF with CNT/PC/solvent solution and impregnation of CNT-coated CF with PC/solvent solution. In addition, hybrid composites were fabricated through surfactant-aided CNT dispersion followed by vacuum filtration. The morphologies of the surfaces of hybrid composites, as analyzed by scanning electron microscopy, revealed the quality of PC impregnation depends on the processing method. Dynamic mechanical analysis was performed to evaluate their mechanical performance. It was analyzed that if the position of the value of tan ${\delta}$ is closer to the ideal line, the adhesion between polymer and carbon fiber is stronger. The effect of mechanical interlocking has a great influence on the dynamic mechanical properties of the composites with CNT-coated CF, which indicates that coating CF with CNTs is a suitable method to fabricate CNT/CF/PC hybrid composites.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.11
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• pp.2971-2980
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• 1995

A numerical study of fluid flow in driven cavity was carried out using singular finite element method. The driven cavity problem is known to have infinite velocity gradients as well as dual velocity conditions at the singular points. To overcome such difficulties, a finite element method with singular shape functions was used and a special technique was employed to allow multiple values of velocities at the singular points. Application of singular elements in the driven cavity problem has a significant influence on the stability of solution. It was found the singular elements gave a stable solution, especially, for the pressure distribution of the entire flow field by keeping up a large pressure at the singular points. In the existing solutions of driven cavity problem, most efforts were focused on the study of streamlines and vorticities, and pressure were seldom mentioned. In this study, however, more attention was given to the pressure distribution. Computations showed that pressure decreased very rapidly as the distance from the singular point increased. Also, the pressure distribution along the vertical walls showed a smoother transition with singular elements compared to those of conventional method. At the singular point toward the flow direction showed more pressure increase compared with the other side as Reynolds number increased.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.228-237
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• 2022

Two-dimensional (2D) nanomaterials have demonstrated the potential to replace silicon and compound semiconductors that are conventionally used in photodetectors. These materials are ultrathin and have superior electrical and optoelectronic properties as well as mechanical flexibility. Consequently, they are particularly advantageous for fabricating high-performance photodetectors that can be used for wearable device applications and Internet of Things technology. Although prototype photodetectors based on single microflakes of 2D materials have demonstrated excellent photoresponsivity across the entire optical spectrum, their practical applications are limited due to the difficulties in scaling up the synthesis process while maintaining the optoelectronic performance. In this review, we discuss facile methods to mass-produce 2D material-based photodetectors based on the exfoliation of van der Waals crystals into nanosheet dispersions. We first introduce the liquid-phase exfoliation process, which has been widely investigated for the scalable fabrication of photodetectors. Solution processing techniques to assemble 2D nanosheets into thin films and the optoelectronic performance of the fabricated devices are also presented. We conclude by discussing the limitations associated with liquid-phase exfoliation and the recent advances made due to the development of the electrochemical exfoliation process with molecular intercalants.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.661-673
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• 2015

This study is about the effects of the solution-focused group art therapy which was implemented for school maladjusted adolescents. The pre-test was conducted for 30 students who had difficulties to adapt school life in K middle school at K city, Gyeonggi province. 20 out of the 30 students were chosen to the participants for this study and randomly divided into an experimental group and control group, with 10 in each group. The experimental group received a 12 session solution-focused group art therapy including pre- and post-tests. This study found that the solution-focused group art therapy program improved the school life adaptation competency of the participants. In conclusion, the findings suggest that the solution-focused group art therapy can be a good approach to help adolescents to improve their school life adaptation ability.

• Strategy21
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• s.40
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• pp.144-161
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• 2016

A unanimous Award has been issued on 12 July 2016 by the Arbitral Tribunal constituted under Annex VII to the United Nations Convention on the Law of the Sea in the arbitration instituted by the Republic of the Philippines against the People's Republic of China. The current security issues in the regional sea shall be carefully reflected to anticipate whether the Award could resolve the existing political conflict or rather will grow military tension in the region. The Award clearly directs the scope of delimiting maritime jurisdiction to coastal States in the Southern China sea, so it seems to help facilitating finding resolutions of regional disputes on maritime boundaries. On the other hand, there are several limitations in reality to implementation of the decisions included in the Award. USA could use the decisions to restrict military activities and exercise of unilateral maritime jurisdiction by China in the region, while China shall encounter guilt to illegitimacy of its activities as well as shaking the legal foundation of its policy in the region. Then the resolution of this dispute through application of international law would rather cause more political confusion. The intension of bringing the case to an international court were to resolve political difficulties. If, however, the political difficulties are not properly reflected in the legal decisions, such decision would possibly raise more political risks.