• 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.

• Journal of Engineering Education Research
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• v.26 no.1
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• pp.3-11
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• 2023

The purpose of this study is to develop Raspberry Pi-based CanSat instruction materials for liberal arts classes to be used in university space education. The educational satellite simulation program is developed by applying the ADDIE program consisting of analysis, design, development, execution, and evaluation of 15 lessons per semester. The usefulness of the instruction materials is evaluated by a validity test of a total of 6 experts. The proposed materials are applied to 100 college students from various majors. To analyze the impact on creative problem-solving ability, a questionnaire is conducted before and after class, and as a result, it is confirmed that there is a significant improvement in all areas after class. The class satisfaction survey is conducted for a total of 10 questions, and the average score is 4.41 out of 5, which is high. In conclusion, the proposed instruction materials make it possible to achieve successful space education using Raspberry Pi and improve creative problem-solving ability in universities.

• Journal of Astronomy and Space Sciences
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• v.36 no.3
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• pp.213-223
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• 2019

This paper analyzes delta-Vs to maintain an extremely low altitude on the Moon and investigates the possibilities of performing a CubeSat mission. To formulate the station-keeping (SK) problem at an extremely low altitude, current work has utilized real-flight performance proven software, the Systems Tool Kit Astrogator by Analytical Graphics Inc. With a high-fidelity force model, properties of SK maneuver delta-Vs to maintain an extremely low altitude are successfully derived with respect to different sets of reference orbits; of different altitudes as well as deadband limits. The effect of the degree and order selection of lunar gravitational harmonics on the overall SK maneuver strategy is also analyzed. Based on the derived SK maneuver delta-V costs, the possibilities of performing a CubeSat mission are analyzed with the expected mission lifetime by applying the current flight-proven miniaturized propulsion system performances. Moreover, the lunar surface coverage as well as the orbital characteristics of a candidate reference orbit are discussed. As a result, it is concluded that an approximately 15-kg class CubeSat could maintain an orbit (30-50 km reference altitude having ${\pm}10km$ deadband limits) around the Moon for 1-6 months and provide almost full coverage of the lunar surface.

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

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.997-1000
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• 2004

Boolean Satisfiability (SAT)는 전산학의 중요한 문제로서 SAT problem을 풀기 위한 많은 알고리즘과 도구들이 제안되어 왔다. 특히, 지난 몇 년 간 많은 발전을 이루어왔고, 하드웨어 검증과 모델 체킹 등의 분야에서 많이 적용되어 왔다. 여러 문제들을 Conjunctive Normal Form (CNF)로 표현하여 CNF의 특성을 이용하여 SAT 알고리즘이 발전되어 왔다. 그런데, 회로를 CNF로 표현할 때 몇 가지 문제점이 발생하는데 특히 CNF는 회로의 structural information 을 잃어버린다는 것이 큰 문제점이다. 이를 보완하기 위하여 회로의 structural information을 이용하기 위한 많은 연구가 진행되어 왔다. 이러한 대부분의 연구는 회로의 정보를 가지고 있다는 경우에 한정된다. 그러나, 하드웨어 검증에서 회로의 정보 없이 검증해야 하는 경우들도 발생한다. 이 논문은 회로의 정보를 가지고 있지 않을 때 CNF 만으로 회로의 structural information을 추론하는 방법을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.530-538
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• 2011

In this paper, the feasibility of LEO(low earth orbit) satellite-based automatic identification system (SAT-AIS) for the coastal area of the South Korea is evaluated in the context of ship AIS transmission detection probability. We evaluate and compare AIS signal detection probability of ORBCOMM satellites and LEO-one satellites considering link budget, SOTDMA protocol and satellite's swath width. The simulation determines the total number of vessels served by those satellites according to satellite's swath width and thus, By simulation results, the ORBCOMM SAT-AIS system outperforms LEO-one SAT-AIS system. The suggested ORBCOMM based SAT-AIS system can be a solution to resolve the existing limited transmission distance problem of the conventional ship-to-shore AIS system.

• Journal of KIISE:Software and Applications
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• v.35 no.11
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• pp.661-670
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• 2008

In some applications of software engineering such as the verification of software model or embedded program, SAT solver is used. To practical use a SAT solver, a problem is encoded to a CNF formula, but because the formula has lower expressiveness than software models or source codes, optimal CNF encoding is required. In this paper, we propose optimal encoding techniques for the problem of "Selecting adjacent $k{\leq}n$ among n objects," Through experimental results we show the proposed constraint is efficient and correct to solve Japanese puzzle. As we know, this paper is the first study about CNF encoding for adjacency in BCC.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.8
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• pp.1-10
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• 1993

In this paper, we will propose 4-move ZKIP and its application. Using bit-commitment scheme that is necessary to organize the ZKIP related to NP-Complete problem and WH and WI preserving the property for security under parallel composition of protocols, we will show that the proposed ZKIP is 4-move ZKIP of SAT comparing to 6-move ZKIP of SAT proposed by Brassard. Chaum and Yung, and under claw-free pairs of function the proposed ZKIP is also 4-move ZKIP comparing to 5-move ZKIP proposed by Goldreich and Krawczyk under the same assumption. Moreover we will show the efficiency of the proposed scheme better than Fiat and Shamir's scheme at the points of computational complexity and communication complexity, and also propose the efficient and secure identification scheme against the chosen ciphertext attack, using the proposed scheme.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.419-427
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• 2018

The purpose of this study is to recycle steel slag generated from the iron producing process and to use steel slag as a construction material which is currently landfilled Steel slag is subjected to aging treatment due to the problem of expansion and collapse when it reacts with water. The Slag Atomizing Technology (SAT) method developed to solve these problems of expanding collapse of steel slag. In this study, experimental study on the emergency repair mortar using the reducing slag, electric arc furnace slag and silicon manganese slag manufactured by the SAT method is Reduced slag was shown an accelerated hydration when it was replaced with rapidly-setting cement, and the rate of substitution was equivalent to 15%. It is shown that the electric furnace oxide slag is equivalent to 100% of the natural aggregate, and it can be replaced by 15-30% when the silicon manganic slag is substituted for the electric furnace oxide slag. With the above formulation, it was possible to design the rapidly repair mortar for road use. These recycling slags can contribute on achieving sustainability of construction industry by reducing the use of cement and natural aggregates and by reducing the generation of carbon dioxide and recycling waste slag.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1149-1157
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• 2017

The satisfiability problem is always a core problem in artificial intelligence (AI). And how to improve the efficiency of algorithms solving the satisfiability problem is widely concerned. Algorithm IER (Improved Extension Rule) is based on extension rule. The number of atoms and the number of clauses affect the efficiency of the algorithm IER. DPLL rules are helpful to reduce these numbers. Then a complete algorithm CIER based on splitting rule and extension rule is proposed in this paper in order to improve the efficiency. At first, the algorithm CIER (Complete Improved Extension Rule) reduces the scale of a clause set with DPLL rules. Then, the clause set is split into a group of small clause sets. In the end, the satisfiability of the clause set is got from these small clause sets'. A strategy MOAMD (maximum occurrences and maximum difference) for the algorithm CIER is given. With this strategy, a better arrangement of atoms could be got. This arrangement could make the number of small clause sets fewer and the scale of these sets smaller. So, the algorithm CIER will be more efficient.