• Polymer(Korea)
• /
• v.33 no.5
• /
• pp.496-500
• /
• 2009

Optically compensated bend liquid crystal display (OCB-LCD) has many application fields owing to its fast response time and wide viewing angle. However, in order to operate the OCB-LCD in bend state, this device needs quick transitions from the initial splay state to bend state. Unlike conventional approach using transient high voltage for the transition, the OCB-LCD with high surface tilt angle, which was achieved by polymerization of UV curable reactive mesogen monomer under certain voltage, was manufactured and the cell showed bend state initially. Electro-optic and electrical characteristics of the cell were analyzed. The cell shows a fast response time owing to high surface pretilt angle and very low residual DC less than 0.1 V although another polymer layer is formed above polymer alignment layers.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.49 no.2
• /
• pp.35-44
• /
• 2012

Most recent infrared (IR) sensors have a focal-plane array (FPA) structure. Spatial non-uniformity of a FPA structure, however, introduces unwanted fixed pattern noise (FPN) to images. This non-uniformity correction (NUC) of a FPA can be categorized into target-based and scene-based approaches. In a target-based approach, FPN can be separated by using a uniform target such as a black body. Since the detector response randomly drifts along the time axis, however, several scene-based algorithms on the basis of a video sequence have been proposed. Among those algorithms, the state-of-the-art one based on Kalman filter uses one-directional warping for motion compensation and only compensates for offset non-uniformity of IR camera detectors. The system model using one-directional warping cannot correct the boundary region where a new scene is being introduced in the next video frame. Furthermore, offset-only correction approaches may not completely remove the FPN in images if it is considerably affected by gain non-uniformity. Therefore, for FPN reduction in IR videos, we propose a joint correction algorithm of gain and offset based on bi-directional warping. Experiment results using simulated and real IR videos show that the proposed scheme can provide better performance compared with the state-of-the art in FPN reduction.

• Korean Security Journal
• /
• no.13
• /
• pp.471-485
• /
• 2007

This study is performed to find out what type instructions are produced to players by coaches and what effects are resulted in cooperative spirit of the concerned group. Furthermore the study has its aims at advancing instructors' skills by using finding of it. The study used 'SPSS 11.0 FOR WINDOW - Statistical Package' to analyze the collected samples and dealt with data of 174 individuals. Statistical analysis of the research for hypothesis verification was about frequency, trust level, mutual relationship, variables, and T-verification. The meaningful level for any result was ranged within 95%(p< .05), 99%(p<.01). The finding are as follows. Effects on pleasure, one of elements of team spirits taken by instructor's training style are analyzed as follows. It was proved to be meaningful in relation with a series of activities like training, democratic, social, compensatory aspects and showed also considerable relation with power based behaviors. That says, players are found to enjoy high pleasure when social and bureaucratic behaviors of instructors are very energetic. In addition to that, training, democratic, and compensatory activities didn't show any meaningful effect. Team spirit was found to play a main role between instructor's behaviors and training, democratic, social rewarding activities. Democratic and social acts influence on team spirit. Looking into the detailed aspects, team spirit was resulted very high in the individuals with low democratic mind and was shown high group spirit by groups with high sociable activities. Teamworks was found to be affected by relation between instructor's acts and training, democratic, social and compensatory aspects and it showed meaningful relations with training, social, bureaucratic behaviors. Low degree of training and bureaucratic activities are found to prefer for power team spirit, and high social activities led a strong teamworks. Group binding spirit was influenced by training, democratic, social compensatory, bureaucratic behaviors and it showed to give effects on democratic, social, and bureaucratic activities of instructors. Low degree of democratic and bureaucratic behaviors are found to produce strong team spirit. In contrast with that, strong social activities was found to be motive of powerful team spirit. Value of team spirit was found to play a main role between instructor's behaviors and training, democratic, social, rewarding activities. It didn't show any meaningful effect on behavior of instructors.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.2
• /
• pp.267-278
• /
• 2011

This study examines the relationship among stock options, pay equity, organizational commitment. Employees who received stock options tend to perceive their pay more equitable and the tendency shows a positive relationship among the amount of stock options and the equity perception. Also employees who received stock options perceive greater procedural equity, as they recognize stock options are awarded to many employees. However, the perception of stock options was not significantly associated with organizational commitment, turnover intention, and pay satisfaction. In 2003, the study surveyed 115 employees who received stock options in 10 publicly owned Korean firms that introduced stock option plans. The statistical analysis leads to the conclusions as follows. First, as the number of stock options increases, the receiver tends to perceive that pay system is more distributively equitable. Second, as the number of stock option receivers increases, the employees perceive the pay system more procedurally equitable. Third, stock option payments don't ensure that it improves pay satisfaction, turnover intention, and organizational commitment. This study shows a positive relationship that stock options work favorably in terms of pay equity, but the effect doesn't seem to be widely positive. The reason is that the introduction of stock options in domestic firms has been made only recently after the foreign exchange crisis in the late 1990s. More experiments and design issues should be discussed for the future.

• Journal of the Institute of Convergence Signal Processing
• /
• v.4 no.4
• /
• pp.47-51
• /
• 2003

Due to the asymptotic property, deadbeat control which is well used in digital control system can not be applied to the continuous time system. But recently by use of the finite Laplace Transform to transfer function and establishment of some settling conditions, CDBC(Continuous time Deadbeat Control) is studied. For CDBC design, transfer function is constituted with delay elements and then order and interpolation conditions are derived. In other way, digital deadbeat controller is implemented and it's output is changed to continuous type by smoothing elements. In this paper multirate sampling is used and so inner controller is sampled faster than output feedback loop. And End order smoothing elements is placed to the output of digital deadbeat controller. By the multirate sampling overall output response is improved. The controller is impleneted as a serial integral compensator in the forward path and a local feedback compensator introduced into the outpute feedback loop. Matlab Simulink is used for simulation.

• Journal of the Korea Convergence Society
• /
• v.8 no.12
• /
• pp.291-298
• /
• 2017

In recent years, the increase of secondary controls within vehicles requires a mechanism to integrate various controls into a single device. This paper presents control performance of an integrated magnetorheological (MR) haptic device which can adjust various in-vehicle comfort instruments. As a first step, the MR fluid-based haptic device capable of both rotary and push motions within a single device is devised as an integrated multi-functional instrument control device. Under consideration of the torque and force model of the proposed device, a magnetic circuit is designed. The proposed MR haptic device is then manufactured and its field-dependent torque and force are experimentally evaluated. Furthermore, an inverse model compensator is synthesized under basis of the Bingham model of the MR fluid and torque/force model of the device. Subsequently, haptic force-feedback maps considering in-vehicle comfort functions are constructed and interacts with the compensator to achieve a desired force-feedback. Control performances such as reflection force are experimentally evaluated for two specific comfort functions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.3
• /
• pp.49-58
• /
• 2000

This paper deals with a systematic approach to neural network controller design for static VAR compensator (SVC) using a learning algorithm of error back propagation that accepts error and change of error as inputs, the momentum learning technique is used for reduction of learning time, to improve system stability. A SVC, one of the Flexible AC Transmission System(FACTS), constructed by a fixed capacitor(FC) and a thyristor controlled reactor(TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage.TO verify the robustness of the proposed method, we considered the dynamic response of generator rotor angle deviation, angular velocity deviation and generator terminal voltage by applying a power fluctuation and rotor angle fluctuation in initial point when heavy load and normal load. Thus, we prove the usefulness of proposed method to improve the stability of single machine-infinite bus with SVC system.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.97-103
• /
• 2006

In this paper, a control method of a mini ozone generator is proposed, and also a cooling technique is described which is cooling down the flowing air gap into a silent discharger to $2^{\circ}C$ to generate ozone of high density and diffusing power. As the digital control system for this method, a double feedback loop is designed which detects the voltage and current of equivalent capacitor of the discharger and compensates for the poor power waveform caused by the noise at high discharging frequency. During the plant modeling of this system, computing time factor is considered as a unique parameter of the power system to improve the transient responses with regard to fluctuating load and to replenish the computing time delay of the controller. Through the experiment, sinusoidal input current for discharger can be acquired and all the effectiveness of this accurate control system over unstable ozone discharger are proved.

• Journal of Broadcast Engineering
• /
• v.15 no.6
• /
• pp.803-814
• /
• 2010

In this paper, we propose a frame structure for modified ATSC transmission systems which is used for a terrestrial 3D HDTV broadcasting. The modified ATSC transmission systems [2] see the potential of increasing a transmission capacity at reasonable TOV (Threshold of Visibility) by modifying channel codes of conventional ATSC systems and varying modulations. We use PN symbols (Pseudorandom Noise) in a guard interval which is used for avoiding the ISI (Inter Symbol Interference) to estimate and compensate the time-varying multi path channel effectively with a maximum transmission payload. With PN symbols in the guard interval, a CIR (Channel Impulse Response) in a time domain can be estimated and a compensation in a frequency domain can be achieved for the accurate channel estimation and compensation. The prosed frame structure is applied to the modified ATSC systems and computer simulations are performed for SER (Symbol Error Rate) performances in TU (Typical Urban)-6 Channel.

• Journal of Sensor Science and Technology
• /
• v.4 no.2
• /
• pp.29-36
• /
• 1995

A constant solid state flow velocity/mass sensor has been fabricated and its characteristics were measured according to flow velocity and fluid temperature. Parameters of the sensor circuit were obtained by simulation using finite difference method. Sensitivity was 10mW/(cm/sec) in the range of flow velocity 0-45cm/sec and response time was within two seconds. For the experiment of fluid temperature variation, the sensor output was compensated at the rate of temperature variation $0.1^{\circ}C/min$, however, with the rate of $0.2^{\circ}C/min$ it took two minutes to be compensated. Since it is not quite often to have such a rate of temperature variation of $0.2^{\circ}C/min$ or more, the developed sensor output can be used for most applications to detect small amount of flow-rate.