• Journal of the Korean School Mathematics Society
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• v.17 no.2
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• pp.139-166
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• 2014

The purpose of the study is to enhance the teaching competence for pre-service elementary teacher by using DGE in order to enhance SMK and PCK for them. To do this, we investigated the initial SMK and PCK for 23 pre-service elementary teachers, the reality of implementation activity of DGE and the change of SMK and PCK after quest activity by DGE. As results, 3 pre-service elementary teachers made errors which are misunderstanding a general angle as special angle, an excessive jump of logic and a circulation logic in the aspect of an initial SMK. In the aspect of contents of PCK, most of pre-service elementary teachers proposed teaching focused on the character using in the problem solving. And most of pre-service elementary teachers proposed teaching methods which are based on explanation, measurement and material manipulation. The reality of implementation activity of DGE was classified 4 cases which are a difficulty in understanding the concept of dynamics and embodying in DGE, an obsession about construction of $75^{\circ}$ and generalization, a difficulty in interpreting 'folding activity' mathematically and a good implementation activity. After quest activity by DGE, the case which is misunderstanding a general angle as special angle could be improved, but the others are not. And after quest activity by DGE, most of pre-service elementary teachers still proposed teaching focused on the character using in the problem solving in the aspect of contents of PCK, and some of pre-service elementary teachers added only teaching methods which are involving visual confirmation by GSP. From these results, we could extract some pedagogical implications helping pre-service teachers to reinforce SMK and PCK by DGE.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.391-393
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• 2004

For performance and stability of a synchronized system, we need an efficient Clock Tree Synthesis(CTS) methodology to design clock distribution networks. In a system-on-a-chip(SOC) design environment, CTS effectively distributes clock signals from clock sources to synchronized points on layout design. In this paper, we suggest the pre-layout analysis of the clock network including gated clock, multiple clock, and test mode CTS optimization. This analysis can help to avoid design failure with potential CTS problems from logic designers and supply layout constraints so as to get an optimal clock distribution network. Our new design flow including pre-layout CTS analysis and structural violation checking also contributes to reduce design time significantly.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.75.1-75.1
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• 2010

This research presents a fuel cell simulator for control logic verification and operator training. Nowadays, power industries are focusing on clean energy as a response to new policy. The fuel cell can be the solution for clean energy, but operating technology is not well developed compared to other conventional power plans because of its short history. Therefore we need a simulator to verify the new control strategy and train operators, because the price of a real fuel cell system is too high and mechanically weak to be used for these kind of purposes. To develop the simulator, a 300 KW MCFC(Molten Carbonate Fuel Cell) system was modeled with stack, BOPs(pre-reformer, steam generator, etc) and mechanical components(valves, pipes, pumps, blowers, etc). The process model was integrated to emulated control system and HMI(Human Machine Interface). A static load and open loop tests were conducted for verifying the accuracy of the process model, since it is the most important part in the simulation. After verifying the process model, an automatic load change and start-up tests were conducted to verify the performance of a new control strategy(logic and functional loops).

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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• pp.179-186
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• 2007

This paper presents new ignition method and ignition recognition logic for a microturbine. New ignition method is designed by constant speed control of a microturbine with pre-determined time during a ignition period. It make more accurate air-fuel ratio as well as give enough time to ignition system to have full performance under cold temperature. And ignition recognition logic is designed by observing output current change of inverter by generating output torque of a microturbine in the instant of ignition. For filtering a output torque current of inverter with high frequency, we applied a moving average method. So far, ignition recognition is usually implemented by measuring of exhausted gas temperature(EGT) of microturbine. The proposed logic can give more accurate judgement of ignition as well as keep a good working of starting system under out of order a temperature measuring system and biased initial value of EGT sensor. Finally, the two proposed logics are proved by field operating a microturbine under various conditions.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.1
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• pp.54-58
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• 2011

In this paper, we use L-fuzzy preopen operator to introduce the degree of pre-separatedness and the degree of preconnectedness in L-fuzzy topological spaces. Many characterizations of the degree of preconnectedness are presented in L-fuzzy topological spaces.

• Journal of Arbitration Studies
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• v.18 no.3
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• pp.51-69
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• 2008

The financial industry in which arbitration is most frequently resorted to so as to resolve disputes is the sector related to the securities industry. Most securities related disputes are raised from broker-dealer controversies which is not new in the Republic of Korea. The disputes between securities brokers and customers are very frequently settled by arbitration in the United States. But the arbitration in the securities area may deprive investors from securities regulation's protection. Introducing the United States' Federal Supreme Courts cases, the author explores the logic of how the pre-dispute arbitration agreement compatible with Securities regulations. However, the author insist the South Korea should more careful in accepting pre-dispute arbitration contract in securities area. Mostly because of the lack of more specific way to secure substantive fairness in securities arbitration. Also the author worries about the possibility of prevailing pre-dispute arbitration agreement in all of the securities investment contract without any other choices, or securities laws' protection. But the author also suggests to introduce public securities arbitration system of the States, and also insists the way to secure substantive fairness, or the application of securities regulations in securities arbitrations. Which may be the pre-requirements for the pre-dispute arbitration agreement in securities investment contract.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.53-56
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• 2001

With the ever increasing clock frequency and integration level of CMOS circuits, I/O(input/output) and interconnect issues are becoming a growing concern. In this thesis, we propose the 2.5Gbps high speed input driver This driver consists of four different blocks, which are the high speed serializer , PECL(pseudo emitter coupled logic) Line Driver, PLL(phase lock loop) and pre-emphasis signal generator. The proposed pre-emphasis block will compensate the high frequency components of the 2.5Gbps data signal. Using the pre-emphasis block, we can obtain 2.5Gbps data signal with differential peak to peak voltage about 900 m $V_{p.p}$ This driver structure is on fabrication in 2.5v/10.25um 1poly, 5metal CMOS process.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.21-26
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• 2016

Canine cataract is developed with aging and can cause the blindness or surgical treatment if not treated timely. The first observation must be made by pet owners but they do not have proper equipment and knowledge to see the abnormalities. In this paper, we propose an intelligent image processing method to extract canine cataract suspicious object from non-professional equipment such as ordinary digital camera and cellular phone photographs so that even casual owners of pet dog can make a pre-diagnosis of such a surgery-needed disease as soon as possible. The experiment shows that the proposed method is successful in most cases except the dog has similar colored hair to the color of cataract.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.2
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• pp.195-208
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• 2009

In this paper, we introduce a grid-based key pre-distribution scheme in wireless sensor networks, which aims to improve the connectivity and resiliency while maintaining a reasonable overhead. We consider simplification of the key establishment logic and enhancement of the connectivity via plat polynomial assignment on a three-dimensional grid for node allocation and keying material assignment. We demonstrate that our scheme results in improvements via a detailed discussion on the connectivity, resource usage, security features and resiliency. A comparison with other relevant works from the literature along with a demonstrated implementation on typical sensor nodes shows the feasibility of the introduced scheme and its applicability for large networks.

• Computers and Concrete
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• v.19 no.2
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• pp.133-142
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• 2017

Two-stage concrete (TSC), also known as pre-placed aggregate concrete, is characterized by its unique placement technique, whereby the coarse aggregate is first placed in the formwork, then injected with a special grout. Despite its superior sustainability and technical features, TSC has remained a basic concrete technology without much use of modern chemical admixtures, new binders, fiber reinforcement or other emerging additions. In the present study, an experimental database for TSC was built. Different types of cementitious binders (single, binary, and ternary) comprising ordinary portland cement, fly ash, silica fume, and metakaolin were used to produce the various TSC mixtures. Different dosages of steel fibres having different lengths were also incorporated to enhance the mechanical properties of TSC. The database thus created was used to develop fuzzy logic models as predictive tools for the grout flowability and mechanical properties of TSC mixtures. The performance of the developed models was evaluated using statistical parameters and error analyses. The results indicate that the fuzzy logic models thus developed can be powerful tools for predicting the TSC grout flowability and mechanical properties and a useful aid for the design of TSC mixtures.