• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.185-194
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• 2005

A Server-Proxies-Users communication system is studied by using Stackelberg strategy theory of game. A new model, in which the server, proxies and users are not equal is established, and that is a three-level programming. The solution existence of the model is proved.

• The Journal of Korean Association of Computer Education
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• v.17 no.5
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• pp.43-51
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• 2014

This study has purpose on analyzing the error types which are identified after middle and high school students perform the online programming assignments and also has the purpose on the analysis of correlation between the frequency of error occurrence according to academic achievement level in programming concept learning and types of errors analyzed previously. For this study, the syntax, logical, and coding errors are analyzed from the performed results of programming research assignment for 88 students. Analyzed results show that the logical error has the highest occurrence rate of 69.3% among three types of errors, and it has been shown meaningful difference in the frequency of error occurrence between three achievement level groups of high, middle, and low. In the correlation analysis of achievement level and error types, it shows negative relationship between logical error and coding error, and therefore it can be concluded that as achievement level is higher, both logical and coding errors tend to occur less. In the correlation analysis in error types, it shows positive relationship between syntax error and coding error.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.53-63
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• 2017

The increasing of wind power penetration level presents challenges in classical optimal reactive power dispatch (ORPD) which is usually formulated as a deterministic optimization problem. This paper proposes a two-stage stochastic programming model for ORPD by considering the uncertainties of wind speed and load in a specified time interval. To avoid the excessive operation, the schedule of compensators will be determined in the first-stage while accounting for the costs of adjusting the compensators (CACs). Under uncertainty effects, on-load tap changer (OLTC) and generator in the second-stage will compensate the mismatch caused by the first-stage decision. The objective of the proposed model is to minimize the sum of CACs and the expected energy loss. The stochastic behavior is formulated by three-point estimate method (TPEM) to convert the stochastic programming into equivalent deterministic problem. A hybrid Genetic Algorithm-Interior Point Method is utilized to solve this large-scale mixed-integer nonlinear stochastic problem. Two case studies on IEEE 14-bus and IEEE 118-bus system are provided to illustrate the effectiveness of the proposed method.

• Journal of KIISE:Software and Applications
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• v.36 no.6
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• pp.498-507
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• 2009

There has been insufficient studies on the effect of programming language learning on logical thinking ability. Each study result on the improvement degree and items of logical thinking ability is different according to the object of the study, its method, and the learning subject, which makes the generalization process difficult. Moreover, the necessity of programming language learning seems not proved, because it is not apparent whether the improvement of logical thinking ability is due to the advancement of knowledge or programming language learning. In this study, we instructed educational programming languages to elementary students in 6th grade for 7 hours, investigated its effect on logical-thinking ability by the meta-cognition level, and compared the result with that of computer skill learning. As a result, for Dolittle, LOGO, and Powerpoint learning groups, the logical-thinking ability of high meta-cognition level students has increased with significance, but that of low meta-cognition level students has significantly increased for Dolittle and LOGO groups only. However, regardless of meta-cognition levels, there was no significant difference of logical-thinking ability between all three groups.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.340-347
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• 2019

Due to advances in machine intelligence and increased demands for autonomous machines, the complexity of the underlying software platform is increasing at a rapid pace, overwhelming the developers with implementation details. We attempt to ease the burden that falls onto the developers by creating a graphical programming framework we named Splash. Splash is designed to provide an effective programming abstraction for autonomous machines that require stream processing. It also enables programmers to specify genuine, end-to-end timing constraints, which the Splash framework automatically monitors for violation. By utilizing the timing constraints, Splash provides three key language semantics: timing semantics, in-order delivery semantics, and rate-controlled data-driven stream processing semantics. These three semantics together collectively serve as a conceptual tool that can hide low-level details from programmers, allowing developers to focus on the main logic of their applications. In this paper, we introduce the three-language semantics in detail and explain their function in association with Splash's language constructs. Furthermore, we present the internal workings of the Splash programming framework and validate its effectiveness via a lane keeping assist system.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.143-155
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• 2001

Generally, truss design has been determined by the designer's experience and intuition. But if we perform the most economical structural design we must consider not only cross-sections of members but also configurations(howe, warren and pratt types etc.) of single truss as the number of panel and truss height. The purpose of this study is to develope automated optimum design techniques for steel truss structures considering cross-sections of members and shape of trusses simultaneously. As the results, it could be possible to find easily the optimum solutions subject to design conditions at the preliminary structural design stage of the steel truss structures. In this study, the objective function is expressed as the whole member weight of trusses, and the applied constraints are as stresses, slenderness ratio, local buckling, deflection, member cross-sectional dimensions and truss height etc. The automated optimum design algorithm of this study is divided into three-level procedures. The first level on member cross-sectional optimization is performed by the sequential unconstrained minimization technique(SUMT) using dynamic programming method. And the second level about truss height optimization is applied for obtaining the optimum truss height by three-equal interval search method. The last level of optimization is applied for obtaining the optimum panel number of truss by integer programming method. The algorithm of multi-level optimization programming technique proposed in this study is more helpful for the economical design of plane trusses as well as space trusses.

• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.147-159
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• 2015

This paper is to design smart based collaborative learning model for programming education of fifth graders of elementary school and applies it to a class and analyze its result. Designed learning model is composed of understanding of concept, realization, learning and sharing and it includes step by step learning materials and smart based collaborative learning activities. Scratch traffic light learning materials at leaning stage classify content to be checked in programming by colors and write to support programming internalization of learners. Provision of smart based collaborative learning activities that considered learning conditions of learners makes it possible for beginners to participate in and keep study actively. This study showed that there was statistically significant difference in learners' programming interest and those who achieved over 8 out of 10 points were 60.7% at three stage evaluations for achievement level that applied learning model which suggests that satisfactory achievement level is achieved.

• Journal of The Korean Association of Information Education
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• v.23 no.6
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• pp.561-571
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• 2019

Programming education generally includes problem analysis process, automation through algorithms and programming, and generalization process. It is a good software education method for students in improving computing thinking. However, it was found that beginners had difficulties in understanding instruction usage, writing algorithms, and implementing programming. In this study, we developed a game programming education model and curriculum for programming education of pre-service teachers. The 4E model consisted of empathy, exploration, engagement and evaluation. In addition, it is configured to learn game core elements and core command blocks by each stage. To help the pre-service teachers understand the use of various programming blocks, a three-step teaching and learning method was presented, consisting of example learning, self-game creation, and team-based projects. As a result of applying and verifying the curriculum for 15 weeks, it showed significant results in the 4E model and pre-service teachers' perception of block programming competence and the level of computational thinking on the submitted game project results was also high.

• Industrial Engineering and Management Systems
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• v.13 no.4
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• pp.369-382
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• 2014

This paper introduces a new multi-product multi-period multi-objective aggregate production planning problem. The proposed problem is modeled using multi-objective mixed-integer mathematical programming. Three objective functions, including minimizing total cost, maximizing customer services level, and maximizing the quality of end-product, are considered, simultaneously. Several constraints such as quantity of production, available time, work force levels, inventory levels, backordering levels, machine capacity, warehouse space and available budget are also considered. Some parameters of the proposed model are assumed to be qualitative and modeled using fuzzy sets. Then, a fuzzy goal programming approach is proposed to solve the model. The proposed approach is applied on a real-world industrial case study of a color and resin production company called Teiph-Saipa. The approach is coded using LINGO software. The efficacy and applicability of the proposed approach are illustrated in the case study. The results of proposed approach are compared with those of the existing experimental methods used in the company. The relative dominance of the proposed approach is revealed in comparison with the experimental method. Finally, a data dictionary, including the way of gathering data for running the model, is proposed in order to facilitate the re-implementation of the model for future development and case studies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.568-579
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• 1995

An off-line programming (OLP) system was proposed and developed in order to save cost and time in adjusting a robot to new workcells or applying new algorithms to actual trajectory planning. The developed OLP system was especially designed to be operated in a PC level host computer. A SCARA robot with four axes was selected as an objective robot. The OLP system developed in this study consisted of such modules as data base, three-dimensional graphics, kinematics, trajectory planning, dynamics, control, and commands. Each module was constructed to form an independent unit so that it can be easily modified or improved. The OLP system was programmed for a graphic user interface in Borland $C^{++}$ language. Some of system operating commands and an interpreter were devised and used for more convenient programming of robot simulations.s.