• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.466-469
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• 2011

Recently, a new theoretical and methodological approach for computational science is becoming more and more popular for analyzing and solving scientific problems in various scientific disciplines such as Computational fluid dynamics, Chemistry, Physics, Structural Dynamics, Computational Design and applied research. Computational science is a field of study concerned with constructing mathematical models and quantitative analysis techniques and using large computing resources to solve the problems which are difficult to approach in a physical experimentally. In this paper, we present R&D of EDISON open integration platform that allows anyone like professors, researchers, industrial workers, students etc to upload their advanced research result such as simulation SW to use and share based on the cyber infrastructure of supercomputer and network. EDISON platform, which consists of 3 tiers (EDISON application framework, EDISON middleware, and EDISON infra resources) provides Web portal for education and research in 5 areas (CFD, Chemistry, Physics, Structural Dynamics, Computational Design) and user service.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.799-801
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• 2011

Computational science is a field of study concerned with constructing mathematical models and quantitative analysis techniques and using large computing resources to solve the problems which are difficult to approach in a physical experimentally. Recently, a new web-based simulation environment for computational science is becoming more and more popular for supporting multi-user access without restriction of space or time, however, to develop web-based simulation applications, the researchers performed their works too much difficulty. In this paper, we present automated web interface generation tool that allows applied researchers to concentrate on advanced research in their scientific disciplines such as Chemistry, Physics, Structural Dynamics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.325-338
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• 2012

In this paper, a radio resource allocation scheme for a multi-hop relay transmission in cognitive radio (CR) system is proposed to support the employment of relay nodes in IEEE 802.22 standard for wireless regional area network (WRAN). An optimization problem is formulated to maximize the number of serving secondary users (SUs) under system constraints such as time-divided frame structure for multiplexing and a single resource-unit to every relay-hop. However, due to mathematical complexity, the optimization problem is solved with a sub-optimal manner instead, which takes three steps in the order of user selection, relay/path selection, and frequency selection. In the numerical analysis, this proposed solution is evaluated in terms of service rate denoting as the ratio of the number of serving SUs to the number of service-requesting SUs. Simulation results show the condition of adopting multi-hop relay and the optimum number of relaying hops by comparing with the performance of 1-hop system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.859-867
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• 2010

In this paper, we consider a novel spectrum sensing system in which firstly, the fusion center (FC) senses and makes the own decision then if its sensing result is not useful for achieving the final decision, the local observations from the cognitive users (CUs) will be required. Moreover, in case that FC needs the results from CUs, we will choose only CU having the highest collected energy to send its local decision to FC. Based on this selecting method, the number of sensing bits can be reduced; hence, we can save the power and the bandwidth for reporting stage in the cognitive radio network (CRN). The mathematical analysis of the key metrics of the sensing schemes (probability of detection, false alarm, e.g.) will be investigated and confirmed by the Monte-Carlo simulation results to show the performance enhancement of the proposed schemes.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.205-218
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• 2012

Mobility management of the mobile nodes and provision of seamless handover is crucial to an efficient support for the global roaming of the mobile nodes in next-generation wireless networks. Mobile IPv6 and mobility management in extended IP layer, which highly depend on traffic characteristics and user mobility models, were proposed by the IETF. Therefore, to evaluate the in-depth performance about these factors is important. Generally, the performance of IPv6-based mobility management protocol is evaluated through simulation. This paper shows the correlation between network parameters and performance metrics through numerical results, which is investigated how influence handoff latency and packet loss. And this paper uses mathematical analysis of the system parameters, such as the subnet residence time, the packet arrival rate and delay in wireless connection through the analytical framework which evaluate the performance of IPv6-based mobility management protocol.

• The KIPS Transactions:PartA
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• v.12A no.2 s.92
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• pp.171-180
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• 2005

In distributed systems data are replicated and stored at several nodes to increase the availability and overall performance. Here Quorum protocol doffing a certain set of replicas required for read/write operation exists for global concurrency control. One of the representative replication Protocols - the Tree Quorum protocol - has a drawback of rapidly growing number of replicas as the level increases, while the Grid protocol requires the same operation cost even without any failure. In this paper, thus, we propose a new replication protocol called hybrid protocol which capitalizes the merits of the existing protocols and solves the problems of them at the same time. The proposed hybrid protocol has very low operation cost in the absence of failure like the tree quorum protocol, and has relatively lower operation cost and higher availability than existing protocols when failure occurs by employing tree architecture as the overall organization while each level of the tree is organized as a row of a grid architecture. It is thus effective to be applied to survival storage system. We conduct cost and availability analysis of the proposed protocol through mathematical modeling, and response time and throughput are compared with those of the Tree Quorum protocol through computer simulation.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.3
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• pp.487-507
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• 2011

Despite the recent increased attention to mathematics teacher education there have been lack of empirical studies on how to teach teachers. A study of mathematics instruction for prospective teachers can be conducted either by a teacher educator's critical reflection on her teaching or by observation of others' teaching practices. This paper was from the author's observation of a mathematics instruction course for future elementary teachers at the University of California at Irvine. As such this paper described in detail how the course was implemented throughout the quarter and drew implications for a teacher preparation program in Korea. As the course had a specific purpose of promoting future teachers' expertise in mathematics instruction and employed various strategies that were different from a typical university course, this paper is expected to provide teacher educators with the insight of an alternative teaching style and to provoke discussion of how to connect theory to practice for effective teacher education.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.3
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• pp.579-598
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• 2011

In this study, the 2011 elementary school mathematics curriculum was analyzed compared to the 2007 elementary school mathematics curriculum with a focus on changes in specified learning topics. First, the topics which are dealt with in the 2011 curriculum were critically discussed. Second, prominent features which can be found in learning topics in 2011 curriculum were found. The following three conclusions which can be obtained from above analyzed results were presented. First, system for curriculum development is necessary to supplement. The process of draft development for public hearing and final curriculum development is not exposed anywhere. It is necessary to clean up and disclose this process in order to study and develop next curriculum. Second, it is necessary to modify the way of stating in curriculum. it is necessary to specify and use the expressions to some extent the meaning of which are not sufficiently established and the meaning of which are ambiguous. Third, the achievement standards set by 2011 curriculum needs to be consistent. The principles for stating achievement standards are necessary. it is necessary to review the link between elementary and middle school curriculum is well-made.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.3
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• pp.505-530
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• 2017

Although mathematically gifted students have potential and creative productivity, they might not manifest group level creative synergy. To manifest group creativity among them, the manifestation process should be facilitated and the process losses should be minimized. The purpose of this study is looking for the method to facilitate the manifestation process of group creativity and minimize the process losses of it. To do this, a case study method was adopted. The products and process losses of the manifestation process of group creativity was analysed. In conclusion, the processes and products of group creativity were concretized and the process losses were analysed by social/motivational and cognitive factors. In addition, the justification and agreement were necessary for the manifestation process of group creativity among mathematically gifted students.

• Journal of Educational Research in Mathematics
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• v.26 no.3
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• pp.527-542
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• 2016

In the mathematics curriculum that was revised in 2009, statistical literacy is explicitly addressed as a goal and specific objectives are included. However, statistical literacy has not been addressed in the studies on KSAT. This study aimed to draw implications on how to improve KSAT in a sense that statistical literacy could be evaluated instead of testing typical facts or skills by comparing KSAT with SAT. We used mathematical problem solving process and category of context of PISA framework (OECD, 2013) to administer the comparison of KSAT and SAT. Result shows that both KSAT and SAT use various context, but items in KSAT is limited in assessing critical understanding. We suggested several ways to develop context-based items for KSAT in which statistical literacy could be assessed.