• Research in Mathematical Education
• /
• v.26 no.2
• /
• pp.83-104
• /
• 2023

Lecture theatres and computing laboratories are common types of classrooms used for teaching and learning in this study; both were equipped with a computer network through which teachers and students can access learning management system, digital library, educational software, and so on. Students were divided into groups of two or three; each group of students collaborated on the worksheets in the laboratory and naturally sat together when attending a class held in the lecture theatre. The social organization of classroom learning would promote student learning but what drives student learning; how to engage students with learning; and how to maintain their interest in learning are of research interest in the present study. The study illustrated the theoretical and empirical links, student motivation has a relation to rich collaboration with peers, communication as verbal interactions as well as teacher-student interactions. These are within socio-cultural contexts for learning to take place. The study was extended to make comparisons of the motivational orientations between student genders. It was found that female students were keener on fun or enjoyment in learning, peer communication, and teacher's intervention, whereas male students were concerned more about digital learning tools, a positive working relationship, social reciprocity, and interpersonal relationships.

• School Mathematics
• /
• v.15 no.4
• /
• pp.975-994
• /
• 2013

In this paper, we analyzed the utilization trend of technology in the secondary mathematics textbooks based on the 6th, 7th and 2007 revised mathematics curriculums in Korea. We analyzed 30, 60 and 90 mathematics books based on the 6th, 7th and 2007 revised mathematics curriculums respectively. The analysis focused on three aspects of using technology, i.e., contents areas in which technology used, technological tools and programs used, and methods of using technology in teaching and learning mathematics. The results shows that the frequency of using technology in mathematics books has been increased as mathematics curriculum has been revised. In the mathematics books based on th 6th curriculum, only 25 scenes were found, but in 7th and 2007 revised curriculum 248 and 355 scenes were found. In the 6th curriculum, calculators and graphing calculators were used mainly, but in the 7th and 2007 revised curriculum many kinds of technological tools and softwares were used including CAS, dynamic geometry software, spreadsheets, programming language, and the Internet. Especially the internet was used frequently in the 7th curriculum. And the methods of using technology has been diversified as time passed. In the 6th curriculum, the technology mainly used for introducing technology and simple calculation, but in the 7th and 2007 revised curriculum the technologies and software were also used for understanding mathematical laws, principles and concepts and students-centered exploring the mathematical properties.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.5
• /
• pp.398-405
• /
• 2014

Recently the embedded software has been widely applied to the safety-critical systems in aviation and defense industries, therefore, the higher level of reliability, availability and fault tolerance has become a key factor for its implementation into the systems. The integrity of the software can be verified using the static analysis tools. And recent developed static analysis tool can evaluate code integrity through the mathematical analysis method. In this paper we detect the autocode error and violation of coding rules using the formal verification tool, Polyspace(R). And the fundamental errors on the flight control law model have been detected and corrected using the formal verification results. As a result of verification process, FBW helicopter control law autocode can ensure code integrity.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.6
• /
• pp.783-790
• /
• 2013

Circular path generation for ball bar measurement using the simultaneous movement of two axes with at least one rotary axis requires the execution of CAM software. However, a change in the machine type or measurement condition requires a new execution of the CAM software, which is cumbersome. This paper presents a circular path generation technique that does not require CAM software and is applicable to different types of driving axes with an arbitrary structural configuration of machine tools and any ball bar setup condition. Mathematical equations are derived for three cases using the proposed technique. In addition, to inspect the measurement feasibility for avoiding physical interference among the ball bar parts, a tilting angle calculation is proposed. The validity of the proposed technique was verified by performing a ball bar experiment with A and C as the simultaneous axes of a five-axis machine tool.

• International Journal of Aeronautical and Space Sciences
• /
• v.14 no.4
• /
• pp.297-309
• /
• 2013

Design optimization is a mathematical process to find an optimal solution through the use of formal optimization algorithms. Design plays a vital role in the engineering field; therefore, using design tools in education and research is becoming more and more important. Recently, numerical design optimization in fluid mechanics, which uses computational fluid dynamics (CFD), has numerous applications in the engineering field, because of the rapid development of high-performance computing resources. However, it is difficult to find design optimization software and contents for educational purposes in aerospace engineering. In the present study, we have developed an aerodynamic design framework specifically for an airfoil, based on the EDucation-research Integration through Simulation On the Net (EDISON) portal. The airfoil design framework is composed of three subparts: a geometry kernel, CFD flow analysis, and an optimization algorithm. Through a seamless interface among the subparts, an iterative design process is conducted. In addition, the CFD flow analysis and the design framework are provided through a web-based portal system, while the computation is taken care of by a supercomputing facility. In addition to the software development, educational contents are developed for lectures associated with design optimization in aerospace and mechanical engineering education programs. The software and content developed in this study is expected to be used as a tool for e-learning material, for education and research in universities.

• School Mathematics
• /
• v.1 no.2
• /
• pp.637-660
• /
• 1999

Although ‘to understand mathematics’ is an important educational purpose, most student do not have a relational understanding of the basic concept of mathematics but have a instrumental understanding. This paper will investigate the possibility of using computers for enhancing relational understanding. In the ‘Qualitative case study’, three students who are in the first grade at E-High school took part in 7 activities during four weeks, and were later interviewed and engaged in informal discussion and were observed. This is the result of this study. 1. The three students were passive participants in mathematics problem solving situation at school. Therefore, student B just applied formulas which she had memorized, and student C would forgot the formulas occasionally. These common students needed to participate actively in doing mathematics. 2. The activities utilized two software healing with connection between graphs and function, giving the students the opportunity to plan, practice, and test by themselves. As a result, they understood the mathematical formulas and rules more deeply through their own trial and error, and then they gained thinking abilities necessary for doing mathematics. In addition, the activities boosted their confidence. 3. The understanding type of students was slightly different. Student A who received a high score, understood the most relationally, but student B who received a very high score, understood instrumentally and so couldn't app1y her knowledge to solving problems related to function concept. Student C who received a middle score lacked knowledge of mathematics but thought more creatively. The result is that students need an opportunity to think rotationally regardless of score. Therefore, this study concludes that using computer software will provide a positive effect for relational understanding in loaming function concept.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.20 no.2
• /
• pp.159-178
• /
• 1995

Supervisory control is an approach based on formal language. it is used to model and control discrete event systems in which each discrete event process is represented as an automation. A supervisor is a generator that switches control patterns in such a way that a given discrete evenet process behaves in obedience to various constraints. A flexible manufacturing cell (FMC) is one of discrete evenet systems. Functions necessary for the operation of an FMC are characterized by operational components and informational compoments. The operational components can be modeled using the finite state machines and the informational components can be modeled using the abstract formalism which describes supporting operations of the cell controller. In this paper, we addressed function required for FMC control specification, software engineering aspects on FMC control based on supervisory control, a concept of event queue for resolving synchronization problem, and complexity reduction. Based on the mathematical model of an FMC. we synthesized the controller by integrating a supervisor for FMC with control specification that specifies event-driven operation of the cell controller. The proposed control scheme is stable mathematically so that the system always behaves on a controlled way even under the existence of uncontrollable events. Furthermore, using an event queue concept, we can solve a synchronization problem caused by the violation of instantaneity assumption of supervisory control theory in real life situation. And also, we can propotype a control software rapidly due to the modularity of the proposed control scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.2
• /
• pp.51-56
• /
• 2017

With the rapid increase in the number of mobile terminals, demand for wireless technologies has sharply increased these days. While wireless communication provides advantages such as ease of deployment, mobility of terminals, continuity of session, and almost comparable transmission bandwidth to the wired communication, it has vulnerability to malicious radio attacks such as eavesdropping, denial of service, session hijacking, and jamming. Among a variety of methods of preventing wireless attacks, the MTD(Moving Target Defense) is the technique for improving the security capability of the defense system by constantly changing the ability of the system to be attacked. In this paper, in order to develop a resilient software defined radio communication testbed system, we present a novel MTD approach to change dynamically and randomly the radio parameters such as modulation scheme, operating frequency, packet size. The probability of successful attack on the developed MTD-based SDR communication system has been analysed in a mathematical way and verified through simulation.

• Journal of the Korea Computer Industry Society
• /
• v.3 no.1
• /
• pp.77-84
• /
• 2002

An cluster system used consist of large number of running servers, one has the problem that does the low availability occured by the high chance of the server failures and it is difficult to provide occuring software aging. In this paper, running cluster web servers consists of n primary servers and k backup servers, based on the operational parameters such as number of running primary servers, number of backup severs, rejuvenation period, rejuvenation time, failure rate of sewers, repair rate of servers, unstable rate of servers. We calculate to evaluate the rejuvenation policy such steady-state probabilities, downtime, availability, and downtime cost. We validate the solutions of mathematical model by experiments based on various operation parameters and find that the software rejuvenation method can be adopted as prventive fault tolerant technique for stability of system. The failure rate and unstable rate of the servers are essential factors for decision making of the rejuvenation policies.

• IEIE Transactions on Smart Processing and Computing
• /
• v.2 no.5
• /
• pp.302-309
• /
• 2013

This paper proposes a mathematical model of Caprine arthritis encephalitis (CAE), which is a disease causing significant economic damage to the goat farming industry, and reports the application of this model to the development of an information management system of animal quarantine to overcome this disease. The mathematical model of CAE was derived from the AIDs model in human case because epidemical characteristics of these diseases including infection pass are similar. This model can be expressed by simultaneous differential equations. Simulations using a new model were performed according Euler's and Runge-Kutta method using numerical analysis software. In each method, strong convergence was observed and the results were similar. The design of an information management system of animal quarantine was proposed as an application of the new model. System design was constructed on the assumption that in subtropical islands, the expected development of information infrastructure and utilization will become valuable in the future.