• Research in Mathematical Education
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• v.16 no.4
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• pp.217-232
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• 2012

While many studies on early algebra have been conducted, there have been only a few studies on the operation sense as the fundamental element of algebraic thinking, especially the fraction operation sense. This study explored the dimensions of fraction operation sense and then investigated students' fraction operation sense. A total of 183 of sixth graders were surveyed and 5 students who showed high operation sense were clinically interviewed in order to analyze their algebraic thinking in detail. The results showed that students had a tendency to use direct calculation or employ inappropriate operation sense rather than to use the structure of operation or the relation between operations on the basis of algebraic thinking. This study implies that explicit instruction on early algebra is necessary from the elementary school years.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.400-406
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• 1997

This paper is concerned with the active vibration control of grid structure by means of piezoceramic actuators and sensors. The control technique used in this paper is based on the positive position feedback(PPF) and the strain rate feedback(SRF) control, which have been successfully used for the vibration control of beam structures. A new control methodology is developed using the PPF and SRF controller of single-input single-output method. The PPF controller is used for the suppression of first bending mode and SRF controller is used for the suppression of higher vibration modes of grid structure. Electric circuits for the realization of control schemes are explained in detail. The control techniques prove its effectiveness by experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.415-420
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• 2006

This paper introduces a new self-bearing motor which combines a homopolar step motor and a passive magnetic bearing. Compared with conventional self-bearing motors which are mostly based on the theory of active magnetic bearings and therefore have some difficulties in design of the complicated flux distribution and control of the levitation force and the torque independently, the proposed self-bearing motor has a very simple and novel structure and operating principle. for the levitation, it works just like passive magnetic bearings which use the repulsive force between permanent magnets. On the other hand, its rotation principle is quite similar to that of a conventional homopolar step motor. In this paper, we introduce the basic structure and the operating principle in detail, and show some results of FEM analysis to predict the performance of the proposed self-bearing motor and further, to get the optimal design parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1348-1353
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• 2006

This paper is concerned with the comparison of component mode synthesis md substructure synthesis methods. Those two methods were developed for the dynamic analysis of complex structure. However, the difference between two methods in solving the dynamic problem has never been explained. In this paper, a structure consisting of two beams is considered for the application of two methods. The dynamic formulation shows the characteristics and differences of two methods. The procedure for choosing proper substructure modes in each method is explained in detail. In addition, the advantage of the substructure synthesis method is discussed based on the numerical example. Numerical examples show how two methods are applied to the addressed problem.

• Journal of the Korea Furniture Society
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• v.15 no.1
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• pp.17-25
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• 2004

In this study, web-sites of home furniture business in Korea have been investigated to understand the conditions for the activation of e-marketing activities. Contents of seven businesses that have been selected for the study was analyzed in three aspects: utility, value of entertainment and structure. Result of the study showed that in the aspect of utility, the web-sites were desired to provide customers with more detail and diverse information rather than simply present description and prices of the products for the purpose of promotion. In the aspect of entertainment value, it was found that the information on the web-sites lacked diversity, originality and expertism, thus requiring for an independent contents development in a way that arouse interest in the web-sites. In the aspect of structure, the web-sites were desired to have interface easy to access and with strong absorption force. To sum up, the examined web-sites were required to diversify their standardized contents in a way that reflects identity of the business and meets diverse needs of customers.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3772-3776
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• 2012

Mitogen-activated protein kinase phosphatase 4 (MKP4) has proved to be a promising target for the development of therapeutics for the treatment of diabetes and the other metabolic diseases. Here, we report an example for a successful application of the structure-based virtual screening to identify three novel inhibitors of MKP4. These inhibitors have desirable physicochemical properties as a drug candidate and reveal a moderate potency with $IC_{50}$ values ranging from 4.9 to $32.3{\mu}M$. Therefore, they deserve consideration for further development by structure-activity relationship studies to optimize the inhibitory and antidiabetic activities. Structural features relevant to the stabilization of the newly identified inhibitors in the active site of MKP4 are discussed in detail.

• Korean Institute of Interior Design Journal
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• v.21 no.6
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• pp.252-259
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• 2012

The aim of this study is in emphasizing the importance of the use of material and the tectonic and their influence on the spatial quality by analyzing Peter Zumthor's projects as case studies. In the research, Zumthor's choice of material, construction method (detail and structure) and the relationship with the context were analyzed in order to illustrate Zumthor's approach in making a strong tie with the locality. Three of Zumthor's projects of different sizes and programs were chosen to heighten the sensitivity of Zumthor's unique working method for each project. Peter Zumthor's architecture is neither superficial nor visually complex. On the contrary, he aims to express through the use of material and construction method, a unique relationship with the physical context, social context and most importantly the actual experience of the space itself. This study aims to contribute towards increasing the awareness and the interest in the materiality and the tectonics which are the fundamentals in spatial experience and spatial identity.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.683-686
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• 2009

We report inverted white OLEDs fabricated by full wet processes. We utilized inverted structure OLEDs since the structure was better for the realization of full wet fabrication of OLEDs. It was found that the performance of inverted OLEDs is comparable to that of conventional OLEDs. In this presentation, we will discuss in detail a few important issues on the full wet fabrication of OLEDs.

• Journal of Information Management
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• v.39 no.2
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• pp.27-43
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• 2008

This paper analyzes feasibility studies regarding the structure, applications and issues of the library RFID system. In this study, the structure and principle, operation mode and middleware of library RFID system are reviewed in detail, Finally this paper analyzed and proposed the RFID applications that could be efficient to information management and user service of library and the major problems and improvements of library RFID system.

• IE interfaces
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• v.13 no.2
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• pp.234-245
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• 2000

In this paper, the conceptual framework of IBS(Intelligent Building Systems) is redefined, and we propose two ANP(Analytic Network Process) models for ranking IBS. Traditional models have ranked IBS according to technical features or the number of elements in IBS. But, we consider relative functional importance among IBS elements for efficient building operation. According to the structure of interactive-relationship among IBS elements, we present two types of model. The one is Model A that is composed of both hierarchical and network structures. It has $12{\times}12$ supermatrix consists of interdependent relationship between 6 benefit elements(Productivity, Saving, Safety, Convenience, Pleasantness, Environment Affinity) and 6 IBS elements(Building Operation, Security, Safety, Telecommunication(TC), Office Automation(OA), other elements). Each of 6 IBS elements has subelements in hierarchical structure. The other is Model B that has $25{\times}25$ supermatrix consists of interdependent relationship between 6 benefit elements and 19 IBS sub elements. Merits and demerits of each model are discussed in detail.