• 한국대기환경학회지
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• 제34권1호
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• pp.87-100
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• 2018

Fast economic growth and urbanization of China have been causing air pollution not only over its domestic but transboundary atmosphere. Recent high fine particle pollution episodes in China made the government move toward more stringent air pollution control policies - which are mostly fuel switching and emissions control. In this research, we tried to understand characteristics of Chinese emissions and their change by analyzing its emissions inventory by year, sector, and region. From the inter-comparison of existing bottom-up emission inventories, we found relatively good agreements (<20% difference) for $SO_2$ and $NO_x$, but 30% or more discrepancies for some pollutants. Inter-comparison with top-down $NO_x$ emissions estimates also showed 20~50% differences by year. The regional distribution and inter-annual changes of emissions revealed different stages of energy/fuel mix and policy penetration. Early increase of pollutants emissions in the eastern part of China might give strong influences to the Korean peninsular in early 2000s but, more stringent control in that region would help improving air pollution in Korea in near future.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.173-178
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• 2001

The cost on transmission and election of precast concrete members largely depends on the weight of them. In this study, the weight of prestressed precast beam could be reduced by control the section and prestressing force to meet the required strength on the basis of the optimum process. The top and bottom concrete stress of the section considered is required to check according to each construction step for this process. The original rectangular beam weight could be reduced up to 50~39% due to the development of a U-beams from the optimum process.

• 전기의세계
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• 제43권3호
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• pp.10-17
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• 1994

패트리네트는 시스템의 관계를 시작적으로 보여주어 시스템의 모델링을 쉽게 만든다. 시스템의 각 부분에 관한 정보를 가지고 전체와 부분에 대하여 하향식(top-down)과 상향식(bottom-up) 설계를 할 수 있게 해준다. 패트리네트는 그래프 표현이므로 FMS(flexible manufacturing systems)등과 같은 실시간 제어(real-time control)의 구현에 사용될 수 있으며 토큰 정보로부터 시스템의 각 부분의 상태를 실시간 감시(monitoring)할 수 있다. 패트리네트는 PLC(programmable logic controller)와 같이 여러 요소시스템(subsystem)을 순서대로 동작시키고 조정한다. 시스테메 대한 페트리네트 모델로부터 시뮬레이션(simulation)을 할 수 있고, 이로부터 성능 평가를 할 수 있다.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.352-359
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• 2016

This paper presents high efficiency 5A synchronous DC-DC buck converter. The proposed DC-DC buck converter works from 4.5V to 18V input voltage range, and provides up to 5A of continuous output current and output voltage adjustable down to 0.8V. This chip is packaged MCP(multi-chip package) with control chip, top side P-CH switch, and bottom side N-CH switch. This chip is designed in a 25V high voltage CMOS 0.35um technology. It has a maximum power efficiency of up to 94% and internal 3msec soft start and fixed 500KHz PWM(Pulse Width Modulation) operations. It also includes cycle by cycle current limit function, short and thermal shutdown protection circuit at 150℃. This chip size is 2190um*1130um includes scribe lane 10um.

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.530-534
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• 2008

The LGP with nanometer structures resulted in enhancement of optical efficiency. Its fundamental mechanism is to recycle the polarized light via one round-trip through QWP(Quarter-wave Plate) but the maximum efficiency to reach with this method is limited up to 2. To get the larger efficiency than this a LGP with 1D PC(one-dimensional photonic crystal) nanometer-patterned on its top and bottom surfaces is suggested. For its optimum design the computer simulation is performed and suggests a grating that the spatial frequency between adjacent patterns is 500nm, its height 250nm, duty cycle 50%, and its cross section is rectangular. The angles of transmitted light are nearly the same as the results expected from the generalized Snell's law. Thus the Mathematica code, developed in this experiment, will be applied to designing the optimized LGP. The LGP with nanometer-patterened 1D PC LGP on its both surfaces shows the enhancement of transmitted intensity distribution up to 5.7 times.

• 한국지능시스템학회논문지
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• 제6권3호
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• pp.51-62
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• 1996

전자감응식 교통신호시스템은 승용차환산계수를 고려하지 않음으로서 과포화상태에서 출발지연시간 및 승용차 대기시간을 유발하고 있다. 본 논문에서는 전처리로,우선 신경망을 이용하여, 하위 교차로의 승용차환산계수를 생성한다. 그러나, 간혹 차량의 무게, 속도가 틀리기때문에 최적주기신호를 부정확하게 산출할 수 있다. 그러므로 후처리로 상위교차로의 포화상태비율에 의한 Feed-Back된 데이터를 이용한 퍼지제어를 함으로서, 과포화시에 승용차대기 시간 및 출발지연시간을 감소기키는 연구이다. 뿐만아니라, 과포화상태에서 앞막힘현상을 예방제어하기 위해서 포화상태비율, 도로길이, 도로경사도, 도로폭등이 같지 않은 상위교차로에서도 앞막힘현상을 예방제어 할 수 있도록 하였다.

• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.149-155
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• 2012

This paper presents mobile robot control architecture of hierarchical behaviors, inspired by biological life. The system is reactive, highly parallel, and does not rely on representation of the environment. The behaviors of the system are designed hierarchically from the bottom-up with priority given to primitive behaviors to ensure the survivability of the robot and provide robustness to failures in higher-level behaviors. Fuzzy logic is used to perform command fusion on each behavior's output. Simulations of the proposed methodology are shown and discussed. The simulation results indicate that complex tasks can be performed by a combination of a few simple behaviors and a set of fuzzy inference rules.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.643-648
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• 2005

Generally, ships have marks of various shapes on outside of the hull. Among them, so called "Draft Mark" indicates the distance from the bottom of the keel to the waterline. Draft marks are used to determine the displacement and other properties of the ship for stability and control purposes. These marks are made up of welding bead or sticking the steel plate on outside of the hull. To improve the confidence level of the ship owner, quality and accuracy of the draft mark is very important. So the automatic mark welding robot is used to enable a high quality and accurate manufacturing line. To improve the system portability, the system is divided into two distinct parts, namely mechanical part and control part. Mechanical part is robust, a lightweight, and easy to dismantle. The control part consists of an in-house developed controller, which is based on embedded Linux. Also, the control part consists of power line communication module to ensure the applicability of the controller in manufacturing line. In this paper, the methodologies of control and configuration of the robot are discussed.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.342-352
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• 1998

A nuclear design feasibility of soluble boron free(SBF core for the medium-sized(600MWe) PWR was investigated. The result conformed that soluble boron free operation could be performed by using current PWR proven technologies. Westinghouse advanced reactor, AP-600 was chosen as a design prototype. Design modification was applied for the assembly design with burnable poison and control rod absorber material. In order to control excess reactivity, large amount of gadolinia integral burnable poison rods were used and B4C was used as a control rod absorber material. For control of bottom shift axial power shape due to high temperature feedback in SBF core, axial zoning of burnable poison was applied to the fuel assemblies design. The combination of enrichment and rod number zoning for burnable poison could make an excess reactivity swing flat within around 1% and these also led effective control on axial power offset and peak pin power, The safety assessment of the designed core was peformed by the calculation of MTC, FTC and shutdown margin. MTC in designed SBF core was greater around 6 times than one of Ulchin unit 3&4. Utilization of enriched BIO(up to 50w1o) in B4C shutdown control rods provided enough shutdown margin as well as subcriticality at cold refueling condition.

• Computers and Concrete
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• 제13권1호
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.