• Journal of the Korean Mathematical Society
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• v.37 no.4
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• pp.625-643
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• 2000

In this paper we formulate an optimal control problem governed by time-delay Volterra integral equations; the problem includes control constraints as well as terminal equality and inequality constraints on the terminal state variables. First, using a special type of state and control variations, we represent a relatively simple and self-contained method for deriving new necessary conditions in the form of Pontryagin minimum principle. We show that these results immediately yield classical Pontryagin necessary conditions for control processes governed by ordinary differential equations (with or without delay). Next, imposing suitable convexity conditions on the functions involved, we derive Mangasarian-type and Arrow-type sufficient optimality conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.13-24
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• 1998

This study aims at examining the safety of the would-be approach channel of LNG Terminal at Kwangyang Harbour, by utilizing Captains 2000 port-design simulator. Six competent shipmasters or navigators participated in this study. The developed model ship was a 70,200DWT (138,000m3) LNG carrier. The environmental conditions were maximum flood-and-ebb current condition and wind condition. To evaluate the navigational safety, two categories were analyzed, which were measures of vessel's proximity and shiphandler's subjective evaluations. With respect to the effects of the worst environmental conditions on transit safety, it was concluded that the would-be approach channel was safe on basis of the support of four tugs of 3,200hp or more and current speed of 0.5knots or less.

• Journal of Power System Engineering
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• v.12 no.6
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• pp.42-49
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• 2008

The most important job in the container terminal area is to handle the cargo effectively in the limited time. To achieve this object, many strategies have been introduced and applied to. If we consider the automated container terminal, it is necessary that the cargo handling equipments are equipped with more intelligent control systems. From the middle of the 1990's, an automated rail-mounted gantry crane(RMGC) and rubber-tired gantry crane(RTG) have been developed and widely used to handle containers in the yards. Recently, in these cranes, the many equipments like CCD cameras and sensors are mounted to cope with the automated terminal environment. In this paper, we try to support the development of more intelligent automated cranes which make the cargo handling be performed effectively in the yards. For this plant, the modelling, tracking control, anti-sway system design, skew motion suppressing and complicated motion control and suppressing problems must be considered. Especially, in this paper, the system modelling and tracking control approach are discussed. And, we design the tracking control system incorporating an observer based on the 2DOF servo system design approach to obtain the desired state informations. In the case of observer design, a weighted $H_{\infty}$ error bound approach for a state estimator is considered. Based on an algebraic Riccati equation(inequality) approach, a necessary and sufficient condition for the existence of a full-order estimator which satisfies the weighted $H_{\infty}$ error bound is introduced. Where, the condition for existence of the estimator is denoted by a Linear Matrix Inequality(LMI) which gives an optimized solution and observer gain. Based on this result, we apply it to the tracking control system design for the transfer crane.

• Journal of environmental and Sanitary engineering
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• v.24 no.1
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• pp.47-55
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• 2009

Indoor air Quality in public facility same as bus terminal and subway station is very important for civil health. The purpose of this study was to investigate the concentration and distribution of PM10 and falling microorganism at the 5 subway stations and bus terminals from Summer 2003 to Summer 2005 in Kyunggi Province. The results were as follows. 1. The highest concentration of PM10 was $187ug/m^3$ at Bucheon Bus Terminal in 2005 while the lowest concentration of PM10 was $78ug/m^3$ at Suwon Bus Terminal in 2003. The year variation of PM10 concentration at the bus terminals in Kyunggi Province was in order of 2005 > 2004 > 2003. The average concentration of PM10 at the five Bus Terminal was $127ug/m^3$. 2. The highest concentration of PM10 was $225ug/m^3$ at Euijungbu Station l in 2004 while the lowest concentration of PM10 was $115ug/m^3$ at Suwon Station in 2003. The year variation of PM10 at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003. The average concentration of PM10 at the five subway stations was $164ug/m^3$. 3. The average amount of falling microoganism at the five bus terminal in Kyunggi Provinc was 201CFU/plate. The minimum is 124 CFU/plate at Seongnam Bus Terminal in 2004 while the maximum is 268CFU/plate at Euijungbu Bus Terminal in summer 2005. The higher concentration of PM10 was 206CFU/plate in 2004 than 199CFU/plate in 2003 and 2005. 4. The minimum is 107CFU/plate at Anyang station in 2003 while the maximum was 263CFU/plate at Euijungbu station in 2003. The average amount of falling microoganism at the five subway stations in Kyunggi Province was 179 CFU/plate. The year variation of falling microorganism at the subway stations in Kyunggi Province was in order of 2004 > 2005 > 2003.

• Journal of Fisheries and Marine Sciences Education
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• v.13 no.2
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• pp.132-145
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• 2001

The cold discharge from LNG(liquefied natural gas) terminal makes the water temperature around the terminal fall down. This temperature reduction may result in serious changes on marine ecosystem of the coastal area. The numerical model experiments of material transport and tidal circulation in the inner bay, Chinhae Bay are investigated in the dispersion of cold discharge from LNG terminal. The condition of ambient water is exposed to tide, tidal current and cold discharge temperature. Simple numerical model experiments highlight the importance of tidal circulation and cold discharge at each case and some results are discussed. The results of this study can be used as the guideline for the site selection of LNG terminals and long-term marine environmental impact assessment.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2081-2086
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• 2005

This paper proposes the receding horizon $H_{\infty}$ predictive control (RHHPC) for systems with a state-delay. We first proposes a new cost function for a finite horizon dynamic game problem. The proposed cost function includes two terminal weighting terns, each of which is parameterized by a positive definite matrix, called a terminal weighting matrix. Secondly, we derive the RHHPC from the solution to the finite dynamic game problem. Thirdly, we propose an LMI condition under which the saddle point value satisfies the well-known nonincreasing monotonicity. Finally, we shows the asymptotic stability and $H_{\infty}$-norm boundedness of the closed-loop system controlled by the proposed RHHPC. Through a numerical example, we show that the proposed RHHC is stabilizing and satisfies the infinite horizon $H_{\infty}$-norm bound.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1714-1721
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• 2007

TECA (Terminal Cabin), the terminal device which offers the information to the driver about the condition of High Speed Train(KTX), analyzes the system of train and plays a role of corrective maintenance guideline to a driver when a breakdown occurs. It also supports the driver to decide the situation of the train by offering a necessary information, in communicating with MPU(Main Processor Unit). For Localization of TECA, it is necessary to analyze communication protocol between TECA and MPU. As a part of analysis, communication protocol between OBCS(on-board computer system) and add-on devices has analyzed for the first step. Also with protocol analyzer appropriate method was offered for TECA and MPU protocol analysis. Finally, by appling proposed method to the drivers consol suitability was verified.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.729-731
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• 2000

This paper presents a simple method for determining the minimum value of capacitance required for initiating self excitation in three-phase self-excited induction generator. Based on the steady-state equivalent circuit model, this paper presents simple and direct method to find the minimum capacitance requirement under R-L load. Using the loop impedance and nodal admittance. the minimum capacitance is determined by self excitation condition. These computed values can be used to predict practically the minimum value of the terminal voltage required for self-excitation. To maintain a constant terminal voltage, a method for determining the frequency, terminal capacitance, and exciting reactance is also described.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.245-249
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• 2009

According to the increase of intelligent vehicles many automotive electric components are installed. The wire harness which connects those also increases. The crimping process for compressing the copper wire bundle into the terminal is a key process to assure the good quality of wire harness. For the case of inadequate forming condition many shape failures such as less-filling, over-filling are happen in the crimping process. Even though the quality of crimping shape is satisfactory the quality check for electrical resistance of wire harness is sometime not satisfied the qualification due to large variation of electrical resistance of wire harness under climate test. This large variation is thought to be related with the malfunction automotive electric system and caused by the internal stress of wire, which occurred during the crimping process. In this paper we develop the 3D-FEM simulation scheme and design methodology of optimum terminal shape. Also the effect of terminal shape on the residual stress is discussed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.1-6
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• 2006

This paper proposes association algorithm using load balancing for efficient AP selection under environment of wireless local area network(WLAN). Our scheme measures arrival time of association information when establishing the connection between access points and access terminal, analyzes the load condition of AP, and applies load balancing. AT selects and sets up low traffic AP by measuring traffic of connected access terminal, which can prevent over-franc of access points under hotspot environment that users access simultaneously. According to the above-described selection in a high speed wireless Internet service based on public WLAN technologies that are currently in operations. Further, it is possible to improve the efficiency of network management.