• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.215-218
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• 2002

In this paper, a dual-frequency printed slot antenna loaded with an open-ring conducting strip and capacitively fed by a coplanar waveguide(CPW) is designed. The designed antenna has a bandwidth of 240㎒(1690㎒-1930㎒) at PCS frequency band and of 160㎒(2380㎒-2540㎒) at WLAN frequency band. In both frequency ranges, pattern and gain requirements are satisfied. The commercial software, IE3D, was used to design slot antenna. The predicted characteristics along with measured data are presented for verification purpose.

• IE interfaces
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• v.9 no.3
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• pp.283-297
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• 1996

The 'flat-bar' is a stiffener which is a component of ships. It is basically a long rectangle and has 'end-cut' shapes at both sides. The paper describes a fast nesting algorithm of the flat-bar, and a procedure to generate cutting path of gas/plasma torch, which is operated by a NC (numerically controlled) gas/plasma cutting machine. Proposed procedures are written in C-language and executable on VAX machine with Open VMS operating system.

• IE interfaces
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• v.8 no.3
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• pp.249-257
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• 1995

Expert system is an effective approach for quality system to be automated and thus to be an essential integrating mechanism in any move towards CIM(Computer Integrated Manufacturing). A quality control expert system is introduced and its relationship to CIM is illustrated in a case study. Process control expert system developed by Kim and Sin[6] has been improved via ODBC(Open DataBase Connectivity) for efficient information network, graph representation using Windows API for rapid response and some new rules for identification of patterns in control charts.

• IE interfaces
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• v.17 no.1
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• pp.104-112
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• 2004

The purposes of the study were twofold: to investigate the stereotype of position and direction that the users expect when operating the handles of a water faucet in different directions, and to collect information about user’s preferred directions. Six hundred subjects, aged from teens to over sixties, participated in the experiment with the procedure of showing them actual water faucets of a lever-type handle and two round-shaped handles mounted on the sink(horizontal plane) and wall(vertical plane). The water faucets presented to the subjects were most widely used devices in our living environment. The results showed that when the handle of the lever-type water faucet was in the 'up' position, 63% of the subjects expected the device was 'open'. When the cold hot separated water faucets were mounted on the horizontal or vertical plane, over 50% of those who answered the 'open' direction of round type handles responded as 'counter clockwise' for a 'hot' water faucet and 'clockwise' for a 'cold' water faucet. In conclusion, this study suggests that water faucet devices be designed and installed in the way that the users expect them to operate.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3128-3132
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• 2010

A disposable solid-state pH sensor was realized by utilizing two nanoporous Pt (npPt) electrodes and a copolyelectrolytic junction. One nanoporous Pt electrode was to measure the pH as an indicating electrode (pH-IE) and the other assembled with copolyelectrolytic junction was to maintain constant open circuit potential ($E_{oc}$) as a solid-state reference electrode (SSRE). The copolyelectrolytic junction was composed of cationic and anionic polymers immobilized by photo-polymerization of N,N'-methylenebisacrylamide, making buffered electrolytic environment on the SSRE. It was expected to make. The nanoporous Pt surrounded by a constant pH excellently worked as a solid state reference electrode so as to stabilize the system within 30 s and retain the electrochemical environment regardless of unknown sample solutions. Combination between the SSRE and the pH-IE commonly based on nanoporous Pt yielded a complete solid-state pH sensor that requires no internal filling solution. The solid state pH sensing chip is simple and easy to fabricate so that it could be practically used for disposable purposes. Moreover, the solid-state pH sensor successfully functions in calibration-free mode in a variety of buffers and surfactant samples.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.6
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• pp.61-74
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• 2004

Hydraulic engineers and scientists working on river restoration recognize the need for a deeper understanding of natural streams as a complex and dynamic system, which involves not only abiotic elements(flow, sediments) but also biotic components. From this point of view, the role played by riverine vegetation dynamics and flow conditions becomes essential. Hydro-mechanic interaction between flow and flexible plants covering a river bed is studied in this paper and some previous works are discussed. Measurements of turbulence and flow resistance in vegetated open channel were performed using rigid and flexible tube. Measuring detailed turbulent velocity profiles within and above submerged and flexible stems allowed to distinguish different turbulent regimes. Some interesting relationships were obtained between the velocity field and the deflected height of the plants, such as a reduced drag coefficient in the flexible stems. Turbulent intensities and Reynolds stresses were measured showing two different regions : above and inside the vegetation domain. In flexible vegetated open channel, the maximum values of turbulent intensities and Reynolds stresses appear above the top of canopy. Method to predict a flow resistance in flexible vegetated open channel is developed by modifying an analytical model proposed by Klopstra et al. (1997). Calculated velocity profiles and roughness values correspond well with flume experiments. These confirm the applicability of the presented model for open channel with flexible vegetation. The new method will be verified in the real vegetated conditions in the near future. After these verifications, the new method should be applied for nature rehabilitation projects such as river restorations.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.383-392
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• 2012

This paper reports the active vibration control of plates using a positive position feedback(PPF) controller with moment pair actuators. The equations of motion of the plates under a force and moment pairs are derived and the equations of PPF controllers are formulated. The numerical active control system is then achieved. The effect of the parameters - gain and damping ratio - of the PPF controllers on the open loop transfer function was investigated mainly in terms of the system stability. Increasing the gain of the PPF controller tuned at a mode, the magnitude of the open loop transfer function is increased at all frequencies without changing the phase behavior. The increase of the damping ratio of the PPF controller leads to decrease the magnitude of the open loop transfer function and to modify its phase characteristics, ie, system stability. Based on the behavior of the gain and the damping ratio of the controller, PPF controller for reduction of the plate vibration can be achieved. Two PPF controllers are designed with their connection in parallel to control the two modes simultaneously. Each PPF controller is tuned at the $1^{st}$ and $2^{nd}$ modes, respectively. Their parameters were determined to remain the system to be stable based on the results of the parametric study. A significant reduction in vibration at the tuned modes can be obtained.

• IE interfaces
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• v.22 no.2
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• pp.153-164
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• 2009

An effective management for reverse flows of products such as reuse, repair and disposal, has become an important issue for every aspect of business. In this paper, we study the Location-Routing Problem (LRP) in the multi-stage closed-loop supply chain network. The closed-loop supply chain in this study integrated both forward and reverse flows. In forward flow, a factory, Distribution Center (DC) and retailer are considered as usual. Additionally in reverse flow, we consider the Central Returns collection Center (CRC) and disposal facility. We propose a mixed integer programming model for the design of closed-loop supply chain integrating both forward and reverse flows. Since the LRP belongs to an NP-hard problem, we suggest a heuristic algorithm based on genetic algorithm. For some test problems, we found the optimal locations and routes by changing the numbers of retailers and facility candidates. Furthermore, we compare the efficiencies between open-loop and closed-loop supply chain networks. The results show that the closed-loop design is better than the open one in respect to the total routing distance and cost. This phenomenon enlarges the cut down effect on cost as an experimental space become larger.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.76-82
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• 2006

Wheels' Direction Indicator, an electronic direction displaying system, provides a driver with information of wheels' direction in real time. The purpose of this study is to develop the system showing on LCD and LED with measuring steering wheel's movement. This system that applies a steering wheel's movement to the data process part will reduce inconvenience that confirms wheels' direction before throughout the open window before driving a car in parking lot.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.615-620
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• 2001

The aim of this paper is to open up a relatively new type in bridge engineering by introducing plan and design of extradosed bridge which is implemented in Sungnam-Janghowon T/K project. The topic encompasses parametric study including the behavior of the bridge relevant to the cable layout, the distance from pier table to the first cable's location, the height of pylon, the stiffness of cross section and wind vibration to ascertain sectional type of bridge and span length. For the purpose of the knowledge base presented here, the important feature of design is recommended such as modeling method, camber control, finite element analysis and heat hydration of pier table. We can verify the issue related to the characteristics of extradosed bridge as a result of study and design endeavor.