• 전자공학회논문지A
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• 제32A권5호
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• pp.31-41
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• 1995

In this paper, the relationship between k consecutive outputs of the conventional differential detector and output of differential detector with k-symbol periods delay for differential MSK and GMSK systems is investigated. It is hown that there exists periodity in modulo-2 sum and product of k successive outputs of the conventional differential detector with the output of a detector with k-symbol periods delay circuit. This relationships are used to achieve performance gains over conventional differential detection. The error rate performance of the method is carried out by computer simulation and performance improvement is achieved for differential MSK and GMSK systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.463-465
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• 1997

For fast response of the dc output voltage in PWM converter, the relationship of power balance of both the input and output should be introduced to the system modeling. Then, a nonlinear control theory using state feedback linearization is useful to control the system. By nonlinear control, the voltage response can be fast, so the size of the output filter capacitor can be reduced as long as the same response is kept. The validity of the proposed scheme is shown from the simulation results.

• Journal of Biosystems Engineering
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• 제25권1호
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• pp.11-18
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• 2000

In precision chemical application increment of biological efficacy with less chemical is the virtue. spraying rate and droplet size is closely related to biological efficacy. this study was performed to develope a spray-control-system that could control spraying rate and droplet size independently. Twin-fluid nozzles were selected and tested to certify if the nozzles were suitable for the objective of this study. Characteritics of the nozzles i.e., spraying rte and droplet size change u8nder the changes of spraying pressure and air pressure were statistically modeled. The model had I to 1 matching property between dependent variables and independent variables. Using the property and the model, inverse relationship could be determined between variables. A feedback spray control system was developed and tested with predetermined error of 5 % in pressure. The system showed 4 % error in spraying rate and 9 % error in droplets size. Performance of the system could be upgraded by fine tuning but, in practical sense keeping air pressure in the field sprayer was the bottle neck of commercialization of the spray system.

• 품질경영학회지
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• 제25권4호
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• pp.185-205
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• 1997

Reliability management requires many activities such as conceptual design, detail design, reliability evaluation and analysis, life testing, and environmental screening, etc.. To perform these activities effectively, a lot of information are required : information for failure mechanism, failure modes, part characteristics, and environmental conditions, etc.. These information should be managed to be used effectively and accurately in reliability activities and feedback to product design and manufacturing. This study identified and characterized these information and classified them according to the reliability activities commonly adopted in many manufacturing industries. IDEF1 was used to define and characterize the flow and the relationship of these reliability information and model is proposed which represents the structure of reliability information systems. The proposed model can be used as a basis for developing reliability management softwares.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권4호
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• pp.215-219
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• 2005

This paper aims at asymptotic stabilization for uncertain dynamic systems with state and input delays. We propose a memoryless state feedback controller which maximizes the delay bound for guaranteeing stability of the system. Using Lyapunov method and linear matrix inequality (LMI) approach, a delay-dependent stabilization criterion is devised by taking the relationship between the terms in the Leibniz-Newton formula into account. The criterion is represented in terms of LMIs, which can be solved by various efficient convex optimization algorithms. Numerical examples are given to illustrate our main method.

• 한국표면공학회지
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• 제39권2호
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.

• 대한전기학회논문지
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• 제45권1호
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• pp.131-138
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• 1996

In this paper, we consider an iterative learning control system(ILCS) consisting of an iterative learning controller, a feedback controller and a controlled plant in the frequency domain. At first, we review the convergence of ILCS. And we give some design guidelines of the ILCS using a nominal model of the plant. Then we present the structured and the unstructured uncertainty bound which guarantees the convergence of the designed iterative learning controller. In particular, we analyze the relationship between the convergence and the magnitude and phase uncertainties. In order to show the usefulness of the proposed analysis and design guidelines, we present some simulation examples. (author). 13 refs., 5 figs.

• Journal of Power Electronics
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• 제9권1호
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• pp.124-131
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• 2009

This paper presents a PWM dc-ac converter regulation using a Single Input Fuzzy PI Controller (SIFPIC). The SIFPIC is derived from the signed distanced method, which is a simplification of a conventional fuzzy controller. The simplification results in a one-dimensional rule table, that allows its control surface to be approximated by a piecewise linear relationship. The controller multi-loop structure is comprised of an outer voltage and an inner current feedback loop. To verify the performance of the SIFPIC, a low power PWM dc-ac converter prototype is constructed and the proposed control algorithm is implemented. The experimental results show that the SIFPIC performance is comparable to a conventional Fuzzy PI controller, but with a much reduced computation time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.125-128
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• 1987

We investigate the feedback linearizability of nonlinear discrete-time system s of a specific form, $x_k=G_{u_k}oF(x_k)$ where F is a diffeomorphism and [$G_{u_k}$] forms an one parameter group of diffeomorphisms. This structure represents a class of systems which are state equivalent to linear ones and approximates the sampled data model of a continuous-time system. It is also considered a relationship between linearizability and discretization.

• Journal of Information Processing Systems
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• 제13권6호
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• pp.1554-1574
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• 2017

This paper introduces a new type of determining factor for Pseudo Random Strings (PRS). This classification depends upon a mathematical property called Finite Induction (FI). FI is similar to a Markov Model in that it presents a model of the sequence under consideration and determines the generating rules for this sequence. If these rules obey certain criteria, then we call the sequence generating these rules FI a PRS. We also consider the relationship of these kinds of PRS's to Good/deBruijn graphs and Linear Feedback Shift Registers (LFSR). We show that binary sequences from these special graphs have the FI property. We also show how such FI PRS's can be generated without consideration of the Hamiltonian cycles of the Good/deBruijn graphs. The FI PRS's also have maximum Shannon entropy, while sequences from LFSR's do not, nor are such sequences FI random.