• School Mathematics
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• v.9 no.1
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• pp.141-160
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• 2007

The purpose of this paper was to evaluate how students apply prior knowledge or experience in solving algebra word problems from the chain of signification-based perspective. Three middle school students were evaluated in this case study. The results showed that the subjects formed similarities in the process of applying knowledge needed for solving a problem. The student A and C used semi-open-end formulas and closed formulas as solutions. They then formed concrete shape for each solution using the chain of signification that was applied for solution by forming procedural similarity. At this time, the chain of signification could be the combination of numbers, words, and pictures (such as diagrams or graphs) or just numbers or words. On the other hand, the student C who recognized closed formulas and her own rule as a solution method could not formulate completely procedural similarity due to many errors arising from number information. Nonetheless, all of the subjects showed something in common in the process of coming up with a algorithm that was semi-open-end formula or closed formula.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2249-2261
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• 1999

In this paper, we describe the design and implementation of the Label Distribution Protocol (LDP) for Multiprotocol Label Switching System. We review the implementation issues of LDP that is required to make a gigabit switched router, and propose a detail design of it. We present the data structures and procedures for the LDP as a result, which are based on IETF standard. We present design issues for applying this to carrier class products. The implemented protocol could afford 40,000 entries of the IP routing table that is required for deploying this system to commercialized data network. Furthermore this system implemented using the standard API of Unix, as a result, it has portability. By implementing LDP based on the international standard and these implementation issues, we expect that the implemented LDP will be interoperable with other commercialized products. We prove the validity of the design of the LDP through prototyping, and also verify the prototype with the specification using the process algebra and the performance analysis.

• Communications of Mathematical Education
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• v.23 no.4
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• pp.1023-1041
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• 2009

The importance of the mathematical education on the ICT environment has been increased as the educational environment has been changed in 21st century. In Korea, many researches on ICT tools have appeared over the last 10 years. But most of researches are depending on the foreign tools, that was one major obstacle on adapting them in our mathematics curriculum. But we found the new open source tool which is called Sage-Math can be in effective solution to resolve those problems. Now we produce what we have done in linear algebra with this Sage-Math and mobile modules.

• Communications of Mathematical Education
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• v.35 no.3
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• pp.323-340
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• 2021

The purpose of this case study is to explore the similarities revealed in the process of solving and generalizing word problems related to systems of linear equations in two variables according to covariational reasoning. As a result, student S, who reasoned with coordination of value level, had a static image of the quantities given in the situation. student D, who reasoned with smooth continuous covariation level, had a dynamic image of the quantities in the problem situation and constructed an invariant relationship between the quantities. The results of this study suggest that the activity that constructs the relationship between the quantities in solving word problems helps to strengthen the mathematical problem solving ability, and that teaching methods should be prepared to strengthen students' covariational reasoning in algebra learning.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.119-129
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• 2019

Although line production systems with finite buffers have been studied over several decades, except for some special cases there are no explicit expressions for system performances such as waiting times(or response time) and blocking probability. Recently, a max-plus algebraic approach for buffer-sharing systems with constant processing times was introduced and it can lead to analytic expressions for (higher) moment and tail probability of stationary waiting. Theoretically this approach can be applied to general processing times, but it cannot give a proper way for computing performance measures. To this end, in this study we developed simulation models using @RISK software and the expressions derived from max-plus algebra, and computed and compared blocking probability, waiting time (or response time) with respect to two blocking policies: communication(BBS: Blocking Before Service) and production(BAS: Blocking After Service). Moreover, an optimization problem which determines the minimum shared-buffer capacity satisfying a predetermined QoS(quality of service) is also considered.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.9
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• pp.289-304
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• 2022

It is necessary to apply process algebra and logic in order to analyze and verify safety requirements for Smart IoT Systems due to distributivity and mobility of the systems over some predefined geo-temporal space. However the analysis and verification cannot be fully intuitive over the space due to the fact that the existing process algebra and logic are very limited to express the distributivity and the mobility. In order to overcome the limitations, the paper presents a new logic, namely for GTS-VL (Geo-Temporal Space-Visual Logic), visualization of the analysis and verification over the space. GTS-VL is the first order logic that deals with relations among the different types of blocks over the space, which is the graph that visualizes the system behaviors specified with the existing dTP-Calculus. A tool, called SAVE, was developed over the ADOxx Meta-Modeling Platform in order to demonstrate the feasibility of the approach, and the advantages and practicality of the approach was shown with the comparative analysis of PBC (Producer-Buffer-Consumer) example between the graphical analysis and verification method over the textual method with SAVE tool.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.109-117
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• 2010

In this study, we consider stationary waiting times in a simple fork-and-join type queue which consists of three single-server machines, Machine 1, Machine 2, and Assembly Machine. We assume that the queue has a renewal arrival process and that independent service times at each node are either deterministic or non-overlapping. We also assume that the Machines 1 and 2 have an infinite buffer capacity whereas the Assembly Machine has two finite buffers, one for each machine. Services at each machine are given by FIFO service discipline and a communication blocking policy. We derive the explicit expressions for stationary waiting times at all nodes as a function of finite buffer capacities by using (max,+)-algebra. Various characteristics of stationary waiting times such as mean, higher moments, and tail probability can be computed from these expressions.

• Honam Mathematical Journal
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• v.33 no.4
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• pp.557-573
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• 2011

Let G be a compact and connected semisimple Lie group, H a closed subgroup, g (resp. h) the Lie algebra of G (resp. H), B the Killing form of g, g the normal metric on the homogeneous space G/H which is induced by -B. Let D be an invarint connection with Weyl structure (D, g, ${\omega}$) in the tangent bundle over the normal homogeneous Riemannian manifold (G/H, g) which is projectively flat. Then, the affine connection D on (G/H, g) is a Yang-Mills connection if and only if D is the Levi-Civita connection on (G/H, g).

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.11
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• pp.56-64
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• 1992

The sum-of-product type MVL (Multiple-valued logic) functions can be directly transformed into the exclusive-sum-of-literal-product(ESOLP) type MVL functions with a substitution of the OR operator with the exclusive-OR(XOR) operator. This paper presents an algorithm that can reduce the number of minterms for the purpose of minimizing the hardware size and the complexity of the circuit in the realization of ESOLP-type MVL functions. In Boolean algebra, the joinable true minterms can form the cube, and if some cubes form a cube-chain with adjacent cubes by the insertion of false cubes(or, false minterms), then the created cube-chain can become a large cube which includes previous cubes. As a result of the cube grouping, the number of minterms can be reduced artificially. Since ESOLP-type MVL functions take the MIN/XOR structure, a XOR circuit and a four-valued MIN/XOR dynamic-CMOS PLA circuit is designed for the realization of the minimized functions, and PSPICE simulation results have been also presented for the validation of the proposed algorithm.

• Korean Journal of Mathematics
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• v.27 no.4
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• pp.977-1003
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• 2019

Let 𝓐 and 𝓑 be two unital C^⁎-algebras and 𝓐 ⊗ 𝓑 be their algebraic tensor product. For two bilinear maps on 𝓐 and 𝓑 with some specific conditions, we derive a bilinear map on 𝓐 ⊗ 𝓑 and study some characteristics. Considering two 𝓐 ⊗ 𝓑 bimodules, a centralizer is also obtained for 𝓐 ⊗ 𝓑 corresponding to the given bilinear maps on 𝓐 and 𝓑. A relationship between orthogonal complements of subspaces of 𝓐 and 𝓑 and their tensor product is also deduced with suitable example.