• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.451-451
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• 2000

This study aims for the optimization of process conditions in a fixed-bed catalytic reactor system with a circulating molten salt bath, in which partial oxidation of propylene to acrolein takes place. Two-dimensional pseudo-homogeneous model is adopted with estimation of suitable parameters and its validity is corroborated by comparing simulation result with experimental data. The temperature of the molten salt and the feed composition are found to exercise significant influence on the yield of acrolein and the magnitude of hot spot. The temperature of the molten salt is usually kept constant. This study, however, suggests that the temperature of the molten salt must be axially adjusted so that the abrupt peak of hot spot should not appear near the reactor entrance. The yield of acrolein is maximized and the position and the magnitude of hot spot are optimized by the method of the iterative dynamic programming (IDP).

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2756-2768
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• 1997

The software Process can be defined as the set of activities, rules, procedures, techniques and tools used within the production of software. A software process model is a conceptual representation of a real world software Process and can be described by process programming languages. In this paper, we present the language constructs of SimFlex designed for object-based software process programming. The design of SimFlex is based on the object concept, so that it can model complex software processes concisely both in syntax and semantics. Since the language constructs of SimFlex are derived from the analysis of major PSEEs and their associated process programming languages, SimFlex includes the core characteristics required for a desirable object-based process programming language. In addition, SimFlex is designed to act as a template software process definition language which could be included in specific PSEEs through customization appropriate to those PSEEs.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.259-266
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• 2015

Among many energy resources, natural gas has recently received a remarkable amount of attention, particularly from the electrical generation industry. This is in part due to increasing shale gas production, providing an environment-friendly fossil fuel, and high risk of nuclear power. Because South Korea, the world's second largest LNG importing nation after Japan, has no international natural gas pipelines and relies on imports in the form of LNG, the natural gas has been traditionally procured by long term LNG contracts at relatively high price. Thus, there is a need of developing an Asian LNG trading hub, where LNG can be traded at more competitive spot prices. In a natural gas spot market, the amount of natural gas to be bought should be carefully determined considering a limited storage capacity and future pricing dynamics. In this work, the problem to find the optimal amount of natural gas in a spot market is formulated as a Markov decision process (MDP) in risk neutral environment and the optimal base stock policy which depends on a stage and price is established. Taking into account price and demand uncertainties, the basestock target levels are simply approximated from dynamic programming. The simulation results show that the basestock policy can be one of effective ways for procurement of LNG in a spot market.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.66-76
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• 2002

Automated welding and soldering are an important manufacturing issue in order to lower the cost, increase the quality, and avoid labor problems. An off-line programming, OLP, is one of the powerful methods to solve this kind of diversity problem. Unless an OLP system is ready for the path optimization in welding and soldering, the waste of time and cost is unavoidable due to inefficient paths in welding and soldering processes. Therefore, this study attempts to obtain path optimization using a genetic algorithm based on artificial intelligences. The problem of welding path optimization is defined as a conventional TSP (traveling salesman problem), but still paths have to go through welding lines. An improved genetic algorithm was suggested and the problem was formulated as a TSP problem considering the both end points of each welding line read from database files, and then the transit problem of welding line was solved using the improved suggested genetic algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.10
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• pp.832-835
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• 2003

The objective of this study is to investigate the possibility of chemical process synthesis purely based on mathematical programming when given an objective, feed conditions, product specifications, and model equations for available process units. A method based on a state space approach is proposed, and applied to an example problem with a reactor, a heat exchanger, and a separator. The results indicate that a computer can automatically synthesize an optimal process without any heuristics or expertise in process design provided that global optimization techniques are improved to be suitable for large problems.

• The Journal of Information Technology and Database
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• v.7 no.2
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• pp.33-45
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• 2000

Uniview system is a client-server system that runs on heterogeneous distributed systems and supports the debugging of various kinds of programs. Its client system provides a unified debugging concept and interface on various debuggers of heterogeneous hosts. Its server system provides debugging services and features openness and scalability by interoperating with one or more debugger processes existing on the same host. Based on FSF(Free Software Foundation)'s gdb and Sun Microsystems's dbx. Uniview system supports C/C++ programming language in various UNIX environments as well as Windows environments. The proposed system was designed and implemented to support the JAVA language, which is prevalently used in recent heterogeneous distributed systems and was partly extended to make a clear analysis of JAVA class file structure. Sun Microsystems's Jdb supplied as a JAVA debugger has very limited functions compared to other programming language debugger. In this paper, Uniview as a JAVA debugging system was implemented to provide debugging technologies which are necessary to debug Java applications but missing in current JAVA language as well as to provide its users with various information.

• The Mathematical Education
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• v.42 no.5
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• pp.623-636
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• 2003

Metacognition is defined to be 'thinking about thinking' and 'knowing what we know and what we don't know'. It was verified that the metacognitive abilities of high school students can be improved via instruction. The purpose of this article is to investigate a new method for activating the metacognitive abilities that play a key role in the Mathematical Problem Solving Process(MPSP). Hyunsung participated in the MPSP using Visual Basic Programming. He actively participated in the MPSP. There are sufficient evidences about activating the metacognitive abilities via the activity processes and interviews. In solving mathematical problems, he had basic metacognitive abilities in the stage of understanding mathematical problems; through the experiments, he further developed his metacognitive abilities and successfully transferred them to general mathematical problem solving.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.2
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• pp.117-129
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• 2005

This paper considers a make-to-order inventory-production system in which customer orders are admitted only when the number of outstanding customer orders is below a value committed by the system. We deal with general distributions for the customer order Inter-arrival, production, and replenishment lead time processes. Monotonicities of the optimal average cost with respect to these distribution parameters are established using sample path coupling arguments. When distributions are given as an exponential one, we implement a sensitivity analysis on the optimal inventory policy and show that it has monotonicities with respect to system costs using dynamic programming.

• Journal of the Semiconductor & Display Technology
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• v.2 no.3
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• pp.25-30
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• 2003

In this study, the controller using TMS320LF2407 low voltage DSP for motor control is designed and realized. It has 40 MIPS calculating ability and its driving voltage is 3.3 V for low power. The peripheral elements, however usually use 5 V and they need voltage transfer interface. In this study, voltage transformation and reducing noise are studied and space vector PWM is adopted as a motor control scheme. According to these methods, the efforts for software programming and calculation processes are reduced. In addition, the hardware is also simplified by substituting the current control part with software programming. Through this study, the DSP based servo controller increases its ability for high performance multi-function on semiconductor transportation equipments..

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.127-128
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• 2015

최근 프로그래밍 교육은 쉽고 재밌게 학습할 수 있는 다양한 교육용 프로그래밍 언어의 보급으로 일반 학생들의 사고력 배양을 위한 효과적인 학습으로 널리 인식되고 있다. 또한 프로그래밍의 효과를 증진시킬 수 있는 다양한 연구가 이루어지고 있고 이러한 연구가 심화 발전하기 위해서는 프로그래밍 학습의 주체인 학생들이 어떻게 프로그래밍 학습을 하는지에 대한 면밀한 연구가 필요하다. 본 연구는 학습이 능동적으로 지식을 구성하는 과정이라는 인지 이론을 토대로 프로그래밍 과정에서의 사고 과정을 분석하고자 한다. 학생들의 인지 과정을 관찰하기 위해서는 학생들이 학습 과정에서 적극적인 의사표현이 중요한 요인이이다. 본 연구에서는 방송이라는 특수한 환경에서 학습자들의 말과 행동을 중점적으로 관찰하여 학습자들의 프로그래밍 과정에서의 인지과정을 분석하고자 한다.