• Proceedings of the Korea Information Processing Society Conference
• /
• 2008.05a
• /
• pp.371-374
• /
• 2008

n개의 이진 변수 집합 중에 k개를 선택하는 카운팅 문제(Counting Problem)들은 여러 방법으로 풀이가 가능하다. 본 논문에서는 카운팅 문제를 풀기 위해 SAT, PB, SMT를 소개하고, 칸 칠하기(Fill-a-Pix) 퍼즐을 예로 들어 카운팅 문제의 인코딩 방법을 제시하고 처리 결과를 비교해 보았다. SAT이 상대적으로 인코딩은 가장 복잡했으나, 처리 시 가장 우수한 성능을 보였다. 따라서 본 논문은 카운팅 문제를 다룰 때에는 SAT이 가장 적합하다는 것을 제안한다.

• Water for future
• /
• v.27 no.2
• /
• pp.155-166
• /
• 1994

Various Eulerian-Lagrangian numerical models for the one-dimensional longitudinal dispersion equation are studied comparatively. In the model studied, the transport equation is decoupled into two component parts by the operator-splitting approach ; one part governing adveciton and the other dispersion. The advection equation has been solved using the method of characteristics following fluid particles along the characteristic line and the results are interpolated onto an Eulerian grid on which the dispersion equation is solved by Crank-Nicholson type finite difference method. In solving the advection equation, various interpolation schemes are tested. Among those, Hermite interpolation polynomials are superior to Lagrange interpolation polynomials in reducing dissipation and dispersion errors in the simulation.

• The KIPS Transactions:PartD
• /
• v.15D no.6
• /
• pp.777-784
• /
• 2008

Recently in the field of model checking, to overcome the state explosion problem, the method of using a SAT-solver is mainly researched. To use a SAT-solver, the system to be verified is translated into CNF and the Boolean cardinality constraint is widely used in translating the system into CNF. In BCC it is dealt with set of boolean variables, but there is no translating method of the sequence among Boolean variables. In this paper, we propose methods for translating the problem, which is extracting a subsequence with length k from a sequence of Boolean variables, into CNF formulas. Through experimental results, we show that our method is more efficient than using only BCC.

• Geophysics and Geophysical Exploration
• /
• v.14 no.3
• /
• pp.242-248
• /
• 2011

By applying analytic method to the uniform model, the intrinsic and scattering quality factor ($Q_i^{-1}$ and $Q_s^{-1}$) was separated for the southeastern part of Korean Peninsula. The Multiple Lapse Time Window Analysis method was used to fit theoretical values with observations obtained 759 earthquake data. While previous study for the Korean Peninsula showed very low $Q_i^{-1}$ and $Q_s^{-1}$ reflecting inactive seismicity, southeastern Korea exhibited relatively high $Q_i^{-1}$ and $Q_s^{-1}$ values interpreted as higher seismicity than the other region in the peninsula.

• Journal of Gifted/Talented Education
• /
• v.20 no.2
• /
• pp.527-546
• /
• 2010

As research results, male schoolchildren were found to solve problems more easily in the area of basic process skills while female schoolchildren were found to solve problems in the area of integrated process skills. Schoolboys showed the high tendency to solve problems in a planning pattern by memory, or solving pattern in which they are fully aware of the contents of both questions and choices in answer sheets, or the pattern which they are fully aware of distracters in answer sheets; in contrast, schoolgirls showed a high tendency to get a good result by analyzing both questions & choices in answer sheets or analyzing a chart, graph and illustration, which explains that female schoolchildren tend to solve problems in more diverse ways than male schoolchildren. In case of a poor achiever, male schoolchildren tend to make a failure while trying to find answers in an inadequately understood state or trying to solve on mistaken memories while doing questions immediately while female schoolchildren showed a lot of solving patterns based on mistaken memories or wrong analyses of a chart, illustration, or graph. Such results are believed to offer the implications on the understanding of male/female schoolchildren in their problem-solving pattern of their exploratory ability in elementary science and on its subsequent program development.

• The Journal of Information Systems
• /
• v.25 no.4
• /
• pp.105-119
• /
• 2016

Purpose The conventional solution methods for production scheduling problems typically focus on the active schedules, which result in short makespans. However, the active schedules are more difficult to generate than the semi active schedules. In other words, semi active schedule based search strategy may help to reduce the computational costs associated with production scheduling. In this context, this paper aims to compare the performances of active schedule based and semi active schedule based search methods for production scheduling problems. Design/methodology/approach Two decoding approaches, active schedule decoding and semi active schedule decoding, are introduced in this paper, and they are used to implement genetic algorithms for classical job shop scheduling problem. The permutation representation is adopted by the genetic algorithms, and the decoding approaches are used to obtain a feasible schedule from a sequence of given operations. Findings The semi active schedule based genetic algorithm requires slightly more iterations in order to find the optimal schedule, while its execution time is quite shorter than active schedule based genetic algorithm. Moreover, the operations of semi active schedule decoding is easy to understand and implement. Consequently, this paper concludes that semi active schedule based search methods also can be useful if effective search strategies are given.

• The Journal of the Korea Contents Association
• /
• v.9 no.1
• /
• pp.89-97
• /
• 2009

The use of database system in application increases day by day. This brought out the DBMS interconnection access problem with rapid increase of the user. To solve these database connection problem, database connection pool has been presented. However, there is much to be desired on user's interconnection access. To improve previous connection pool architecture, we have designed the sub connection pool besides main connection pool in this paper. We defined connection pool broker to manage both main and sub connection pool connection. When main connection pool reached its limitation, connection pool broker transfers a connection from a main connection pool to a sub connection pool. When the interconnection access user increased rapidly, we have proved that the suggested sub pool architecture is more effective on response time by comparing it with other existing DBMS connection pool architectures using simulation.

• Journal of Educational Research in Mathematics
• /
• v.8 no.2
• /
• pp.753-762
• /
• 1998

This Paper reports results of investigating the relationship between students' perfoonance and mathematics imtructiooal system in understanding of the function concept. A written examination measuring calcullli students' understanding of the fimction concept was administered to two groups of students whose educatiooal oockground were different. One group consists of students who completed a pre-calculus course in Korea and the other group completed the same course in the United States. This study investigates how students in two groups acquire an understanding of major aspects of the function concept and provided interesting insights regarding the different background and belief related to their performance. Follow-up interviews were conducted to identify possible explanations for the different performance of the two groups in understanding the function concepts. Results indicate that the differences came from the educational environment and individual belief.

• Journal of the Korean School Mathematics Society
• /
• v.15 no.4
• /
• pp.699-718
• /
• 2012

The purpose of mathematics eduction is to develop the ability of thinking mathematically. It informs method to solve problem through mathematical thinking that teach mathematical ability. Errors in the problem solving can be thought as those in the mathematical thinking. Therefore analysis and classification of mathematics errors is important to teach mathematics. This study researches the preceding studies on mathematics errors and presents the characteristic of them with analyzed models. The results achieved by analysis of the process of problem solving are as follows : ▸ Students feel much harder to solve words problems rather than multiple-choice problems. ▸ The length of sentence make some differences of understanding of the words problems. Students easy to understand short sentence problems than long sentence problems. ▸ If students feel difficulties on the pre-learned mathematical content, they feel the same difficulties on the words problems based on the pre-learned mathematics content.

• KIPS Transactions on Software and Data Engineering
• /
• v.1 no.2
• /
• pp.91-102
• /
• 2012

Computer aided language learning has become popular. But the level of automation of constructing a Korean learning assistant system is not so high because a practical language learning system needs large scale knowledge resources, which is very hard to acquire. In this paper, we propose a Korean learning assistant system that utilizes easily obtainable knowledge resources like a corpus, web documents and a lexicon. Our system has three modules - problem solving, pronunciation marker and writing assistant. Automatic problem generator uses a corpus and a lexicon to make problems with one correct answer and three distracters, then verifies their suitability by utilizing frequency information from web documents. We analyze pronunciation rules for a pronunciation marker and recommend appropriate words and sentences in real-time by using data extracted from a corpus. In experiment, we evaluate 400 automatically generated problems, which show 89.9% problem suitability and 64.9% example suitability.