• Bulletin of the Korean Mathematical Society
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• v.60 no.1
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• pp.83-91
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• 2023

A ring R is called a UN ring if every non unit of it can be written as product of a unit and a nilpotent element. We obtain results about lifting of conjugate idempotents and unit regular elements modulo an ideal I of a UN ring R. Matrix rings over UN rings are discussed and it is obtained that for a commutative ring R, a matrix ring M_n(R) is UN if and only if R is UN. Lastly, UN group rings are investigated and we obtain the conditions on a group G and a field K for the group algebra KG to be UN. Then we extend the results obtained for KG to the group ring RG over a ring R (which may not necessarily be a field).

• Electronics and Telecommunications Trends
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• v.38 no.6
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• pp.128-136
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• 2023

Lithium accounts for only 0.0017% of the earth crust, and it is produced in geographically limited regions such as South America, the United States, and China. Since the first half of 2017, the price of lithium has been continuously increasing, and with the rapid adoption of electric vehicles, lithium resources are expected to be depleted in the near future. In addition, economic blocs worldwide face intensifying scenarios such as competition for technological supremacy and protectionism of domestic industries. Consequently, Korea is deepening its dependence on China for core materials and is vulnerable to the influence of the United States Inflation Reduction Act. We analyze post-lithium secondary battery technologies that rely on more earth-abundant elements to replace lithium, whose production is limited to specific regions. Specifically, we focus on the technological status and issues of sodium-ion, zinc-air, and redox-flow batteries. In addition, research trends in post-lithium secondary batteries are examined. Post-lithium secondary batteries seem promising for large-capacity energy storage systems while reducing the costs of raw materials compared with existing lithium-based technologies.

• Smart Structures and Systems
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• v.18 no.6
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• pp.1189-1202
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• 2016

This paper describes an application of wavelet analysis for damage detection of a steel frame structure with bolted connections. The wavelet coefficients of the acceleration response for the healthy and loosened connection structure were calculated at each measurement point. The difference of the wavelet coefficients of the response of the healthy and loosened connection structure is selected as an indicator of the damage. At each node of structure the norm of the difference of the wavelet coefficients matrix is then calculated. The point for which the norm has the higher value is a candidate for location of the damage. The above procedure was experimentally verified on a laboratory-scale 2-meter-long steel frame. The structure consists of 11 steel beams forming a four-bay frame, which is subjected to impact loads using a modal hammer. The accelerations are measured at 20 different locations on the frame, including joints and beam elements. Two states of the structure are considered: healthy and damaged one. The damage is introduced by means of loosening two out of three bolts at one of the frame connections. Calculating the norm of the difference of the wavelet coefficients matrix at each node the higher value was found to be at the same location where the bolts were loosened. The presented experiment showed the effectiveness of the wavelet approach to damage detection of frame structures assembled using bolted connections.

• Korean Journal of Computational Design and Engineering
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• v.6 no.3
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• pp.169-173
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• 2001

Presented in this paper is a CPO tool-path linking procedure optimizing technological objectives, such as dealing with islands (positive and negative) and minimizing tool retractions, drilling holes and slotting. Main features of the proposed algorithm are as follows; 1) a data structure, called a 'TPE-net', is devised to provide information on the parent/child relationships among the tool-path-elements, 2) the number of tool retractions is minimized by a 'tool-path-element linking algorithm'fading a tour through the TPE-net, and 3) the number of drilling holes is minimized by making use of the concept of the 'free space'.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.153-166
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• 2015

This paper proposes a trans-media branding for the trans-media-based cultural content marketing strategy. Trans-media brand analytical framework is proposed with previous studies. And mobile messenger Character 'Line Friends' is analyzed for the text. Trans-media branding is accessible through a multi-platform in the technological environment. Consumer culture, as well as participate include business models to generate revenue also as brand equity. While the character elements that make up the story from the perspective of cultural content storytelling act as an independent cultural goods. Character is segmented elements. Therefore, trans- media branding of the characters are more meaningful. 'Line Friends' trans-media branding can be summarized as follows: First, it takes advantage of the characteristics of the existing Information-Technology-based mobile. Second, it puts consistently found the content of the attributes of Mobile Messenger 'communication' and 'friendship'. And third, while the content of each platform is constantly linked with other platforms, the brand is positioned inside the window effect.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.207-210
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• 1997

The drastic structural changes in telecommunications industry are imposing new strains on operators, regulators and customers. Many researchers have offered diverse frameworks for the changes from the perspectives of sociology, technology, and/or economics. However, there have been few attempts to document the competitive phenomena from management perspectives because of the technological complexities and dynamism in the fundamental transition of competition. In this study, we examine competitive environment in telecommunications industry, and identified five structural elements; telecom operator, competitors, regulation, suppliers, and customer demand. The suggested framework is used to provide a basis for explaining the changes in the characteristics of individual elements and the interactions among them. The dynamic industry-specific changes will be explained through an evolutionary model. We specify the characteristics of progressive stages and the determinants of the evolution. Changes are reviewed in terms of five criteria; regulations and competitions, value chain, technology, customers demand, and internal operations. The result of this study will be useful in analyzing and predicting industry structure and major participants' strategic behaviors and decision patterns. This study can alse be extended to other industries facing dynamic structural changes.

• Journal of the Korea Furniture Society
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• v.17 no.2
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• pp.81-87
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• 2006

Design that is emotionally gratifying is a product design that has been produced by considering user's emotions to give satisfaction through a compositive integration of environmental elements, user's psychological and cognitive element and products' physical elements. In the 21c, where this process of integration is much more appreciated, it could be predicted that the competitiveness of a product relies not on technological aspect but on how close the product to a human being as a communication aid. In the world these days, the changes of lifestyle has been excelled due to the rapid growth of scientific technology. It is needed more than ever for the designers to participate in Human Sensibility Ergonomics to cope with the changes and to design products that are emotionally correct. Therefore, Human Sensibility Ergonomics and design should work closely, organizing a system to sharing the research outcomes and investing opportunities for numerous researchers to study.

• Journal of the Korean Society for Library and Information Science
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• v.29
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• pp.231-255
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• 1995

This study is on the external environment of University library organization, to establish the theoretical background of scientific organization. The library is heavily influenced by its environment and much of the library manager's time is spent trying to reduce these envitronmental influences. The library, basic facility of the university has two environments: external and internal. The external environment is consist of educational, political, economical, cultural, technological and physical environment in society, Internal environment is consist of the university and the library condition. Several subjects of external environment which effect the construction of library organization are selected the elements of this study.

• Journal of the Korea Furniture Society
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• v.14 no.1
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• pp.79-89
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• 2003

Today's aesthetics and design orientations seem to be: flexibility, mobility, multi-functionality required front user's new needs. Our spaces have changed increasingly contain the needs of constant mobility and ability to adapt to a wide variety of situations. For efficient use, a modular system in furnishing can manage the spaces with components which are easy to assemble and disassemble. The function comes from spacial technological structure that is an 'union' formed by units to joint each other. The repeated module is tailored to unchanging environmental conditions. On the other hand, the structure defined by change reacts flexibility to a dynamic environment. In decision-making, it is flexible and able to adapt. Their ability to be positioned freely anywhere in the room allows individual tasks to be carried out by different people, and their almost endless variety of uses create distinctive spaces for living.

• Journal of Korean Society for Quality Management
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• v.27 no.1
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• pp.1-17
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• 1999

To satisfy the needs of customers, firms must supply customers with products of high quality. This requires firms establish a quality management system which pursues customer satisfaction in a business strategy. Quality management must be connected with the strategic chain and the firm can obtain excellent performances only when top management leadership which places people over profit is exercised. The purpose of this study is to analyse whether elements of strategic quality management has any effect on quality and business performances. A questionnaire was used for the survey. In this study, it is showed that elements of strategic quality management(strategy, leadership, customer satisfaction, quality improvement activity, technological innovation, shop floor management, employee participation) are positively correlated with the quality and business performances. This tells firms have to carry out the strategic quality management effectively based on the strategic chain and emphasizing leadership.