• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.3
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• pp.32-41
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• 2008

In this paper, we describe the synthesis of robust and non-fragile $H^{\infty}$ state feedback controllers for linear systems with affine parameter uncertain tracking servo system of blu-ray disc drive, as well as static state feedback controller with polytopic uncertainty Similarity any other control system, the objective of the track-following system design for optical disc drives is to construct the system with better performance and robustness against modeling uncertainties and various disturbances. Also, the obtained condition can be rewritten as parameterized linear matrix inequalities(PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a resulted polytopic region.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.63-69
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• 2021

Flipped learning is necessary for modern education but quite difficult to implement. In pedagogical science, the question remains to what extent the practical work of the teacher in combination with the technologies of flipped learning will improve the quality of higher education. The aim of this article is to study the effectiveness and feasibility of using flipped learning technologies, assessing their perception by students (advantages and problems), identified an algorithm for introducing flipped learning technology in higher education institutions. Research methods. The main method is an experiment. An evaluation of the effectiveness of the study was conducted using a questionnaire and observation method. Statistical methods were used to evaluate the results of the experiment. The research hypothesis is that flipped learning allows the teacher to spend more time on an individual approach, to understand the real needs of students, and provide effective feedback, thereby improving the quality of learning and motivation of students, especially while studying complex material. The results of the study are to prove the effectiveness of the technology of flipped education in the study of complex disciplines, courses, topics. The use of flipped learning strategies improves the self-regulation of the educational process, group work skills, improves students' ability to learn, overcome difficulties. The technology of flipped learning in the presence of modern technical means and constant work on improving the level of digital literacy is an effective means for students to master complex topics and problematic issues that require additional consideration and discussion. The perspective of further research is the consideration of integrated approaches to the application of flipped learning technologies to the principles of STEAM-education, multilingual and multicultural programs, etc. It is also worth continuing to develop a set of methods aimed at enhancing the student's learning activities, the formation of group work skills, direct participation in creating the foundations of higher education.

• Archives of design research
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• v.17 no.4
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• pp.119-128
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• 2004

There is a lack of user centered design methods that support effective collaboration between designers and end-users for designing hardware and software integrated digital products. This paper presents the application of Collaborative Design and a new collaborative design prototyping tool for interactive digital product design projects. The tool consists of STCtools(State Transition Chart tools) software, hardware modeling materials, and physical interface toolkits for integrating software and hardware. STCtools allow users to create and edit States, to compose Events describing transitions between States, and to run intermediate or final results of STC. Using the hardware modeling materials and the physical interface toolkit, designers and end-users can collaborately examine the hardware and software integrated concepts in an early stage of the design process. Three collaborative design workshops of designing a portable digital guide for a theme park were accomplished to examine the feasibility of the tool. The results suggested that the tool supported iterative concept development and interactions between designers and end users. Although several user interface problems of STCtools were identified, the participants gave positive feedback on the role of the tool in collaborative concept generation and deployment. It is expected that the results of this study contribute not only to the collaboration between designers and end users, but also to the collaboration between designers, and between designers and other professionals.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.652-664
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• 2017

The practice of producing and transmitting TV programs with uneven loudness can harm audiences' welfare in the digital environment where audiences are entitled to be offered quality broadcasting service. The purpose of this paper is to investigate issues concerning the digital loudness policy institutionalized in Korea since May 2016, and to offer policy suggestions. This paper reviews previous studies on audience welfare in digital broadcasting, focusing on the close link between loudness policy and audience welfare. In order to explore the state of international policy, this paper examines loudness standards developed by international standardization organizations including ITU, ATSC, and EBU, along with loudness regulations in the US, the UK, Canada, Australia, Japan, and Korea, respectively. Based on the analysis, this paper suggests recommendations for policy makers and broadcasters. First, policies on mandating regular monitoring and establishing penality system should be established for broadcasters not to violate loudness standards. Second, broadcasters are recommended to collect audience feedback, to be equipped with loudness measuring devices, to offer personnel training programs, and to check the compliance of loudness standards when they outsource TV programs.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.15-21
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• 2008

This paper discuss the sequential digital logic systems and arithmetic operation algorithms which is the important material in computer architecture using analysis and synthesis which is based on extension logic for binary logic over galois fields. In sequential digital logic systems, we construct the moore model without feedback sequential logic systems after we obtain the next state function and output function using building block T-gate. Also, we obtain each algorithms of the addition, subtraction, multiplication, division based on the finite fields mathematical properties. Especially, in case of P=2 over GF($P^m$), the proposed algorithm have a advantage which will be able to apply traditional binary logic directly.The proposed method can construct more efficiency digital logic systems because it can be extended traditional binary logic to extension logic.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.417-420
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• 1987

For an increased level of productivity, it is important that the end-point of a robot manipulator moves from an initial location to final position in the minimum time subject to the available maximum actuator's torque (or force) at each joints. The main issue is to develop an algorithm to compute the actuators in real-time. In this paper, a digital state feedback control algorithm has bean developed to obtain the near-minimum-time trajectory for the end-effector of a robot manipulator. In this algorithm, the poles of the linearized closed loop system are judiciously placed in the Z-plane to permit minimum-time response without violating the constraints on the actuator torques. The validity of this algorithm have been established using numerical simulations. A three-link manipulator in chosen for this purpose and results are discussed for three different combinations of initial and final station.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.180-187
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• 1998

The stability and theoretical performance limits of the feedback controlled force reflecting haptic manipulator have been discussed. All the virtual environment which interact physically with the haptic system have its own stable performance limit. Three different realization of the interfaces have been compared using the driving point admittance. The haptic system which is separated from the human hand or finger is superior to its stable interaction provided that there is a means to apply a direct damping between the haptic manipulator and the human finger Electro-magnetic force is used for its digital implementation of the simple separated type haptic device. The stable limits of a virtual wall is calculated and experimental results show that there is performance limits in this implementation.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.238-243
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• 1986

Distillation columns are widely used in almost every chemical plant. The use of multivariable control for such units is attractive because of the strong interactions exhibited between outputs and inputs and the desire to control simultaneously both top and bottom products. In this research design of a robust multivariable controller for distillation column was considered; output feedback controller with proportional and integral modes was designed using pole assignment. The transfer function matrix was obtained by fitting the step response realtions between single input double output pairs of variables. This matrix was then converted to linear time invariant state space model by multivariable realization technique. With the proposed multivariable proportional and integral controller applied to the process, the result of the digital computer simulation showed a good performance of asymtotic tracking. The limited experimental performance of this multivariable control was compared with the result from simulation. It was found that the proposed controller performed satisfactorily for the distillation column which separated binary mixture of methanol and water.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.181-187
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• 2003

This paper presents an 125MHz, 128-phase phase-locked loop using interpolation technique for digital timing recovery. To reduce the power consumption and chip area, phase interpolation was performed over only selected windows, instead of overall period. Four clocks were used for phase interpolation to avoid the output jitter increase due to the interpolation clock (clock used for phase interpolation) switching. Also, the output clock was fed back to finite-state machine (FSM) where the multiplexer selection signals are generated to eliminate the possible output glitches. The PLL implemented in a $0.25\mu\textrm{m}$ CMOS process and dissipates 80mW at 2.5V supply and occupies $0.84\textrm{mm}^2.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.226-235
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• 1992

This paper is concerned with the robust control of LQ state feedback regulators with poles in a specified region in the presence of system uncertainty. The robust stability results for the constant and nonlinear time varying perturbations are derived in terms of bounds of the perturbed system matrices and the weighting matrices in the performance index of LQ problem. The theoretical results are applied to the gap control problem of an attractive-type-magnetic levitation system and the effectiveness is proved by the implementation of digital control using 16 bits microcomputer.