• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.699-702
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• 2005

This paper describes a high speed interface using redundant multi-valued logic for high speed communication ICs. This circuit is composed of encoding circuit and decoding circuit. Because of the multi-valued data conversion, this circuit makes it possible to achieve higher operating speeds than that of a conventional binary logic. Using this logic, a 1:4 DEMUX (demultiplexer) was designed using a 0.35um standard CMOS technology. Proposed circuit is achieved an operating speed of 4.5Gb/s with a supply voltage of 3.3V and with power consumption of 53mW.

• Journal of Applied Reliability
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• v.15 no.4
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• pp.256-261
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• 2015

The aim of this paper is to present some issues to be discussed in relation to failure rate of a system that has identical parallel units. It is assumed that Time-to-Failure of each unit has the same exponential distribution and all units are repairable with a periodic maintenance of time interval T. Effective failure rate is widely recommended for nonrepairable systems as the reciprocal of MTTF but it should not be applied for repairable systems if delayed maintenance is used. And equivalent failure rate of an imaginary system is taken into consideration, the reliability value of which is the same as that of the redundant system when time interval T is given. With a numerical example, failure rate, effective failure rate, and equivalent failure rate of the redundant system are analyzed comparatively.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.85-88
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• 2008

예비 슬라이스(Redundant picture)는 에러가 발생하기 쉬운 환경에서 비디오가 전송될 때 에러를 보상하기 위한 H.264/AVC 부호화 표준의 도구들 중에 하나이다. 본 논문에서는 예비 슬라이스의 삽입으로 인해 발생하는 오버헤드 비트와 손실률을 고려한 LA-RDO(Loss-aware rate-distortion optimization) 모델을 제시하며 제안하는 모델에 기초해서 예비 슬라이스의 삽입 여부를 결정한다. 실험결과는 제안하는 방법이 참조 소프트웨어(JM: Joint Model)에 있는 HRP(Hierarchical redundant picture)와 비교했을 때 평균 0.5dB의 PSNR이 증가함을 보였다. 특별히 낮은 비트율에서 상대적으로 높은 성능을 보이므로 비디오 화상 회의와 같이 낮은 비트의 영상을 요구하는 무선 전송 환경에 적합할 것으로 보인다.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.1125-1128
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• 1998

A new architecture for high-speed implementation of adaptive decision-feedback equalizer (ADFE) applicable to wide-band digital wireless modems is described. Rather than using conventional two's complement arithmetic, a novel complex-valued filter structure is devised, which is based on redundant binary (RB) arithmetic. The proposed RB complex-valued filter reduces the critical path delay of ADFE, as well as leads to a more compact implementation than conventional methods. Also, the carry-propagation free (CPF) operation of the RB arithmetic enhances its speed. To demonstrate the proposed method, a prototype chip set is designed. They are designed to contain two complexvalued filter taps along with their coefficient updating circuits, and can be cascaded to implement loger filter taps for high bit-rate applications.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.168-172
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• 2003

This paper presents a non-electrical isolated Prototype of N+X redundant UPS with two-quadrant converter. Proposed topology has multi-functions of battery charge and discharge regulation, operates with a near unity input power factor, compensates unbalanced voltage on U bus capacitors, and regenerates the circulating active power among the inverters into battery or grid. And furthermore, this system adopts a novel wireless parallel operation algorithm of N+X redundant UPS system with no control interconnections. Simulation and experiment results are provided in this paper to prove the validity of proposed topology and wireless control algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.486-490
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• 1993

In addtion to a basic motion task, redundant manipulators can achieve some additional tasks by optimizing proper performance criteria. Some of performance criteria can be transformed to inequality constraints. So the redundancy resolving problem can be reformulated as a local optimization problem with equality constraints for the end effector and inequality constraints for some performance criteria. In this article, we propose a method for solving the inverse kinematics of a manipulator with redundancy using the Kuhn-Tucker theorem to incorporate inequality constraints. With proper choice of inequality constraints, the proposed method gives a way of optimizing multiple criteria in redundant manipulators.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.398-404
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• 2012

A fault detection process is necessary for high integrity systems like satellites, missiles and aircrafts. Especially, the satellite has to be expected to detect faults autonomously because it cannot be fixed by an expert in the space. Faults can cause critical errors to the entire system and the satellite does not have sufficient computation power to operate a large scale fault management system. Thus, a fault detection method, which has less computational burden, is required. In this paper, we proposed a modified PCA (Principal Component Analysis) as a powerful fault detection method of redundant IMU (Inertial Measurement Unit). The proposed method combines PCA with the parity space approach and it is much more efficient than the others. The proposed fault detection algorithm, modified PCA, is shown to outperform fault detection through a simulation example.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1375-1381
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• 2007

In this paper, we propose a linear modeling and identical PD controller design scheme for the three-pole hybrid-type AMB recently developed in the laboratory, which consists of three permanent magnets, providing bias flux, three Hall diodes, measuring rotor displacements, and ring type permanent magnet bearing, stabilizing in axial and tilting directions. Along the three physical coordinates formed by three poles, we introduce the redundant coordinate system and three identical decoupled controllers to construct linear model. The experiments are also carried out in order to verify the effectiveness of proposed controller in stabilizing the transient and steady state response of rotor.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.766-773
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• 2001

Omni-directional mobile robots have been popularly employed in several application areas. However, the kinematics for these systems have not been clearly identified, specially for redundantly actuated case which is common in omni-directional mobile robot such as the Nomadic model. For such mobile robot systems, exploitation of redundant actuation as well as singularity analysis has not been extensively addressed. In light of this fact, this paper introduces two different kinematic approaches for omni-directional mobile robots. Then, a singular-free load distribution scheme for redundantly actuated three-wheeled omni-directional mobile robot is proposed. Through simulation, several advantages of redundantly actuated mobile robot in aspect of singularity avoidance, minimization of torque norm, and exploiting several subtasks are presented.

• IE interfaces
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• v.25 no.4
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• pp.382-392
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• 2012

Reactor protection system to keep nuclear safety and operational economy of plants requires high reliability. Such a high reliability of the system can be achieved through the redundant design of components. However, common cause failures of components reduce the benefits of redundant design. Thus, the common cause failure analysis, to accurately calculate the reliability of the reactor protection system, is carried out using alpha-factor model. Analysis results to 24 operating months are that 1) the system reliability satisfies the reliability goal of EPRI-URD and 2) the common cause failure contributes 90% of the system unreliability. The uncertainty analysis using alpha factor parameters of 0.05 and 0.95 quantile values shows significantly large difference in the system unreliability.