• Journal of Astronomy and Space Sciences
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• 제23권3호
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• pp.209-216
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• 2006

Ion acoustic solitary wave in a plasma consisting of electrons and ions with an external magnetic field is reinvestigated using the Sagdeev's potential method. Although the Sagdeev potential has a singularity for n < 1, where n is the ion number density, we obtain new solitary wave solutions by expanding the Sagdeev potential up to ${\delta}n^4$ near n = 1. They are compressiv (rarefactive) waves and shock type solitary waves. These waves can exist all together as a superposed wave which may be used to explain what would be observed in the solar wind plasma. We compared our theoretical results with the data of the Freja satellite in the study of Wu et al. (1996). Also it is shown that these solitary waves propagate with a subsonic speed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.466-469
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• 2006

We have developed the world's thinnest flexible electrophoretic displays (EPDs). The thin-film displays are 95 ..m thick, which is nearly the same thickness as a standard sheet of paper. Weighing 0.44g including external connection cables, these displays are also probably the world's lightest. We have also developed 7.1-inch-diagonal(paperback-sized) high-resolution flexible EPDs. The displays are large enough to be used as practical e-paper. More than 7 million transistors work correctly on plastic, enabling us to see 3-megapixel images. These flexible displays include active-matrix TFT devices that are fabricated using Suftla transfer technology. Suftla technology demonstrates the potential to achieve thin, flexible displays that will be used as an e-paper in the near future.

• Journal of the Korean Institute of Telematics and Electronics C
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• 제34C권8호
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• pp.49-63
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• 1997

This paper presents a current sensor that detects defects in CMOS integrated circuits using the current testing technique. The current sensor is built in a CMOS integrated circuit to test an abnormal current. The proposed circuit has a very small impact on the performance of the circuit under test during the normal mode. In the testing mode, the proposed circuit detects the abnormal current caused by permanent manufacturing defects and determines whether the circuit under test is defect-free or not. The proposed current sensor is simple and requires no external voltage and current sources. Hence, the circuit has less area and performance degradation, and is more efficient than any previous works. The validity and effectiveness are verified through the HSPICE simulation on circuits with defects.

• Journal of Korean Institute of Industrial Engineers
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• 제41권6호
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• pp.559-571
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• 2015

To strengthen competences, most of firms have co-operated with external partners. This increases the possibility of unexpected conflicts between firms due to the intellectual property litigation. A suitable intellectual property strategy for firms has to be developed to settle this issue. This study aims to analyze an utilization of intellectual property strategy in firms, and tries to suggest a concept of IP roadmap to support intellectual property strategy planning aligned with technology planning process. For the purposes, we derive five types of intellectual property strategy of firms using Korea Innovation Survey. Then, we explore significant affecting factors using a decision-tree and conduct in-depth analysis for them. Lastly, we suggest a concept of IP roadmap, which can be a supporting tool for developing intellectual property strategy in firms, based on analysis results.

• Journal of the Korean Society of Industry Convergence
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• 제18권1호
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• pp.53-60
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• 2015

For high-accuracy position control of a linear motor, it has been proposed a nonlinear controller including a synchronization algorithm. Linear motors are easily affected by force ripple, friction, and parameter variations because there is no mechanical transmission to reduce the effects of model uncertainties and external disturbances. Synchronization error is also caused by skew motion, model uncertainties, and force disturbance on each axis. Nonlinear effects such as friction and ripple force are estimated and compensated for. The synchronization algorithm is used to reduce the synchronous error of the two side pillars. The performance of the controller is evaluated by computer simulations.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.49-49
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• 2009

Phosphors with oxide host material, YAG:$Ce^{3+}$ and $(Ca,Sr,Ba)_2SiO_4:Eu^{2+}$ yellow phosphor, has been used for LED applications. The WLEDs using these phosphors are widely used for LCD backlighting, automobile, and general lighting applications since they have high conversion efficiency and good thermal and chemical stability which can meet necessary life time of LED products up to now. With advances of LED chip technology, the external quantum efficiency and driving current in chip get higher so that the phosphors for high power chip are required to maintain high conversion efficiency and stability at high temperature due to the heat dissipated from LED chips. In addition, higher color rendering index of LED lighting and color reproducibility of LCD than those of LEDs with single yellow phosphors are required. In order to overcome these technical issues rising from evolution of LED technology, new phosphors are in demand and nitride phosphors, one of the promising new candidate materials, will be discussed here.

• Proceedings of the KIEE Conference
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.80-82
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• 2005

This paper presents the dynamic characteristics of a linear brushless DC(BLDC) motor with permanent magnet excitation for the precision conveyor according to the load condition. In order to investigate the accurate dynamic performance of tile linear BLDC motor driving with 6 step inverter- fed, finite element techniques coupling with external circuit models, together with the simultaneous simulation of motion of the mover system, arc proposed. The results of finite element analysis arc compared to the experimental ones.

• Proceedings of the Technology Innovation Conference
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• 기술경영경제학회 1993년도 제4회 학술발표회
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• pp.119-147
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• 1993

This paper explores the relationships between technological acquisition strategies of small firms and innovation in the Korean Electronics industry. Its thesis is that small firms' technology strategies and their effects on the rate of innovation differ according to the new and traditional technology settings. A primary finding of this study is that in-house R & D and technical linkages with buyers and suppliers have stronger effects on the radical innovation in the new technology setting rather than in the traditional technology setting. The findings of the study provides insight for interpreting inconsistent results of recent research for the importance of external linkages to innovation. They also suggest some implications of small firms' strategies and public policies for accelerating technological innovation.

• Asian Journal of Innovation and Policy
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• 제10권3호
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• pp.274-293
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• 2021

Utilizing outside knowledge for innovation is an important task for companies in the competitive economy. Due to the rapid advance in the internet communication technology, the number and quality of innovation sourcing methods are increasing. We select co-creation, personalization and in-house R&D as the representative forms of innovation sourcing and suggest a game theory model that enables the comparative analysis between them. The decision and surplus outcome of the innovation mechanisms are compared under various settings of the input parameters of the model. The stakeholders voluntarily participate into all mechanisms when the product price is moderately high and the participation cost is low, while co-creation is the only feasible one when the product quality is niche. When the participation cost is relatively high, personalization outperforms co-creation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제21권8호
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• pp.32-42
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• 2022

Asymptotic tracking of a non-minimum phase nonlinear system has been a popular topic in control theory and application. In this paper, we propose a new control scheme to achieve asymptotic output tracking in anon-minimum phase nonlinear system for periodic trajectories through an iterative learning control with the stable inversion. The proposed design method is robust to parameter uncertainties and periodic external disturbances since it is based on iterative learning. The performance of the proposed algorithm was demonstrated through the simulation results using a typical non-minimum nonlinear system of an inverted pendulum on a cart.