• Journal of Chest Surgery
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• v.43 no.5
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• pp.475-481
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• 2010

Background: We evaluated mid-term results of mitral annuloplasty using a flexible band and a completely rigid ring for mitral valve repair in patients with degenerative mitral regurgitation (MR). Material and Method: From January 2004 to September 2008, 71 patients (M:F=36:35, $55{\pm}13$ years) underwent mitral valve repair with mitral annuloplasty for degenerative MR. Ring annuloplasty was done using a Cosgrove-Edwards flexible band (Group I, n=43) or a Carpentier-Edwards classic ring (Group II, n=28). There were no differences in preoperative characteristics of the participants. Average duration of follow-up was 36 months (range: 2~69 mos). Result: There was no in-hospital mortality. Postoperative morbidity, which included atrial fibrillation (n=7) and low cardiac output syndrome (n=5) in groups I and II were similar. There was one late death in group II. The proportion exhibiting freedom from recurrent mitral regurgitation ($\geq$moderate) at 4 years in Groups I and II were, respectively, 94.5 and 91.8%, (p=0.695). Left ventricular ejection fraction decreased in the early postoperative period ($7{\pm}2$ days) and recovered by last follow-up ($25{\pm}16$ mos; p=0.002). The pattern was similar in groups I and II (p=0.905). Re-operation was performed in 3 patients (1 in Group I and 2 in Group II, p=0.316). Four-year event-free survival (free of adverse valve-related events) was 95.2% for Group I and 92.6% for Group II; this difference was not significant, p=0.646). Conclusion: The type of technique used in mitral annuloplasty to repair the mitral valve repair after degenerative MR did not affect mid-term clinical and functional results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2430-2434
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• 2005

Automatic FPC punching instrument for the improvement of working condition and cost saving is introduced in this paper. FPC(flexible printed circuit) is used to detect the contact position of K/B and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation is done manually, the accuracy of the punching degree is varied with operator's condition. Recently, The punching accuracy has deteriorated severely to the 2mm punching reference hall so that assembly of the K/B has hardly done. To improve this manual punching operation to the FPC, automatic FPC punching system is introduced. Precise mechanical parts like a 5-step stepping motor and ball screw mechanism are designed and tested and low cost PC camera is used for the sake of cost down instead of using high quality vision systems for the FA. 3D Mechanical design tool(Pro/E) is used to manage the exact tolerance circumstances and avoid design failures. Simulation is performed to make the complete vision based punching machine before assembly, and this procedure led to the manufacturing cost saving. As the image processing algorithms, dilation, erosion, and threshold calculation is applied to obtain an exact center position from the FPC print marks. These image processing algorithms made the original images having various noises have clean binary pixels which is easy to calculate the center position of print marks. Moment and Least square method are used to calculate the center position of objects. In this development circumstance, Moment method was superior to the Least square one at the calculation of speed and against noise. Main control panel is programmed by Visual C++ and graphical Active X for the whole management of vision based automatic punching machine. Operating modes like manual, calibration, and automatic mode are added to the main control panel for the compensation of bad FPC print conditions and mechanical tolerance occurring in the case of punch and die reassembly. Test algorithms and programs showed good results to the designed automatic punching system and led to the increase of productivity and huge cost down to law material like FPC by avoiding bad quality.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.891-899
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• 2024

The Fourth Industrial Revolution is centered on a personalized demand fulfillment economy and is all about transformation and flexible processing that can deliver what customers want in real time across space and time. This paper implements the construction and operation of a packaging platform that can instantly procure the required packaging products based on real-time orders and evaluates its performance. The components of customer satisfaction are flexible and dependent on the situation which requires efficient management of enterprise operational processes based on an e-SCM platform. An OMS optimized for these conditions plays an important role in maximizing and differentiating the efficiency of a company's operations and improving its cost advantage. OMS is a system of mass customization that provides efficient MOT(Moment of Truth) logistics services to meet the eco-friendly issues of many individual customers and achieve optimized logistics operation goals to enhance repurchase intentions and sustainable business. OMS precisely analyzes the collected data to support information and decision-making related to efficiency, productivity, cost and provide accurate reports. It uses data visualization tools to express data visually and suggests directions for improvement of the operational process through statistics and prediction analysis.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.1
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• pp.19-29
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• 2000

Because the previous simulation tool for attitude control of satellite was designed for the modeling of rigid body and PD controller, the attitude error can be made more than the limitation value for keeping for communication link, and then the communication link can be lost at moving of satellite. So, for rapid attitude restoration and design of stable and modernized controller, the modelling of rigid body and flexible body structure for moving GEO and LEO satellites were performed. Also the minimum time controller is designed for the rapid restoration of attitude error at communication broken and to minimize the disconnection period from ground communication system during the satellite stationkeeping. The linear regulator is designed using the space state vector that is better than accuracy and stability of PD controller. Firstly the simulation was performed for comparison of the rigid and stability of PD controller. Firstly the simulation was performed for comparison of the rigid and flexible models using PD controller and the case of the pitch angle changing by ground command, and the case of the periodic north-south stationkeeping are performed for the analysis of response characteristics of each controller when the attitude is changed. As a result, the flexible body model represents more sililar results of real situation than the rigid body model. The minimum time controller can restore 7 times rapidly than PD controller for its lost attitude. The linear regulator has several merits for capability of adaptation against the external disturbance, stability and response time. In future, we can check the estimated results using this satellite model and controller for real operation. Futhermore the development of new controller and training can be supported.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.4
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• pp.353-361
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• 2016

This work presents an investigation of the radio frequency characteristics of an FTLPGS (fishbone-type transmission line employing periodic ground structure) fabricated on PES (polyether sulfone) for the realization of a transparent flexible wireless communication device. According to the results, the FTLPGS on PES showed a shorter wavelength characteristic when compared with a conventional coplanar waveguide. Concretely, the wavelength of the FTLPGS was 1.91 mm at 50 GHz, which was 48.5% of the conventional coplanar waveguide. The bandwidth extraction result showed that the passband of the FTLPGS on PES was 250 GHz. Unlike conventional periodic structures, the characteristic impedance of the FTLPGS on PES also showed a very low frequency dependency. A miniaturization of the RF circuit on the PES substrate was made possible by the FTLPGS on PES having shown characteristic impedance lower than that of conventional transmission lines. These results mean that, with a broadband operation frequency, the FTLPGS on PES is a suitable construction application for the transmission line and distributed passive components.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.94-99
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• 2014

Recently, trends in new transportation system development have been primarily focused on sustainable and ecofriendly mobility solutions. The personal rapid transit (PRT) system has been considered a promising candidate in this category; its competitiveness is being improved through convergence with cutting-edge electric vehicle (EV) technologies. However, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. In this study, a design approach for a solar-power assisted PRT system is presented with small-scale demonstrations aimed at circumventing challenges facing its adoption, as well as helping speed the transition to electric-powered ground transportation. From the results, it is expected that flexible photovoltaic (PV) cells will be able to supply 11% of the power required by the service equipment installed in a prototype vehicle. In particular, flexible photovoltaic (PV) cells are advantageous in terms of cost, weight, and design considerations. Most importantly, the cells' flexibility and attach-ability are expected to give them great potential for extended application in various areas.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.273-285
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• 2003

Generally, vector spatial data, with richer information than raster spatial data enabledata, enables a mere flexible and effective manipulation of the data sets. However, one of challenges against the publication of vector spatial information on the Internet is the efficient transmission of the big and complex vector spatial datadata, which is both large and complex, across the narrow-bandwidth of the Internet. This paper proposes a new transmission method, namely, the Scale-Dependent Transmission method, with the purpose of improving the efficiency of vector spatial data transmission on the narrow-bandwidthacross the Internet. Simply put, its nam idea is “Transmit what can be seen””. Scale is regarded as a factor naturally associated with spatial features so that not all features are visible to users at a certain scale. With the aid of the Wavelet-Wavelet-based Map Generalization Algorithm, the proposed method filters out invisible features from spatial objects according to the display scale and then to transmit onlytransmits only the visible features as athe final answer for an individual operation. Experiments show that the response times ofan individual operation has been reducedoperations were substantially by the usage of reduced when using the proposed method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.353-358
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• 2005

The purpose of this study is to implement concept of public to passenger ship route to promote benefits and adopt competition principle among ship companies to elevate business efficiency. As of year 2005, passenger ships operate in 106 routes departing from 10 harbors including Mokpo, Masan, and Inchonto provide transportation system to island residents. Contrast to other public transportation systems excluding some tourism routes, this essential passenger ship are unable to fulfill various customer services to the passengers due to stagnation or declination. In addition, route adjustment and flexible passenger ship operation are not expected due to private property right of the route. Therefore, establishment of public transportation system for remote island route is initiated for the connection between cities and islands, boost travel industry of island economy, and balanced growth oh the nation.

• Convergence Security Journal
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• v.8 no.1
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• pp.35-42
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• 2008

While an information system and administration for an application that a user contacts with raise a head by an important problem, a system approach and methodology for administration are mentioned. Authentication technology of various configuration is used, but non-efficiency by complicated authentication administration and operation inappropriate use are for a successful expansion of various and new business of wire/wireless environment. In addition, under the mobile computer environment with different authentic method each other, it is difficult at all to expect flexible and continuous service. Under the ubiquitous computing environment, It is very important thing plan to research and develop compatibility and the side of variance authentication plan that preservation characteristics are helped. Hereby, This paper look around an requirement items and authority mechanism for the administration and the operation mechanism of the distributed authentication considering expansion possibility of the ubiquitous computing environment not only fixed computing environment but also mobile computing. In future, we expect it by can guide positive participation about distributed authentication technique of the genuine ubiquitous environment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.40-40
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• 2008

$InGaZnO_4$ based thin film transistors (TFTs) are of interest for large area and low cost electronics. The TFTs have strong potential for application in flat panel displays and portable electronics due to their high field effect mobility, high on/off current ratios, and high optical transparency. The application of such room temperature processed transistors, however, is often limited by the operation voltage and long-tenn stability. Therefore, attaining an optimum thickness is necessary. We investigated the thickness dependence of a room temperature grown $MgO_{0.3}BST_{0.7}$ composite gate dielectric and an $InGaZnO_4$ (IGZO) active semiconductor on the electrical characteristics of thin film transistors fabricated on a polyethylene terephthalate (PET) substrate. The TFT characteristics were changed markedly with variation of the gate dielectric and semiconductor thickness. The optimum gate dielectric and active semiconductor thickness were 300 nm and 30 nm, respectively. The TFT showed low operating voltage of less than 4 V, field effect mobility of 21.34 cm2/$V{\cdot}s$, an on/off ratio of $8.27\times10^6$, threshold voltage of 2.2 V, and a subthreshold swing of 0.42 V/dec.