• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.8
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• pp.598-609
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• 2003

This paper describes a CMOS IF PLL frequency synthesizer. The designed frequency synthesizer can be programmed to operate at various intermediate frequencies using different external LC-tanks. The VCO with automatic amplitude control provides constant output power independent of the Q-factor of the external LC-tank. The designed frequency divider includes an 8/9 or 16/17 dual-modulus prescaler and can be programmed to operate at different frequencies by external serial data for various applications. The designed circuit is fabricated using a 0.35${\mu}{\textrm}{m}$ n-well CMOS process. Measurement results show that the phase noise is 114dBc/Hz@100kHz and the lock time is less than 300$mutextrm{s}$. It consumes 16mW from 3V supply. The die area is 730${\mu}{\textrm}{m}$$\times$950${\mu}{\textrm}{m}$.

• Journal of the Korean Home Economics Association
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• v.42 no.6
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• pp.73-88
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• 2004

The purpose of this study was to explore the influences of family resources, i.e. objective resources, perceived adequacy of resources, locus of control, social support, family cohesion, and family adaptability on caregiving stress for dementia elderly in homemakers. The subjects of this study were 141 married women who had cared for dementia elderly. The survey method was a questionnaire. And the data was analyzed by means of Cronbach's, factor analysis, and multiple regression. The main findings were as follows： First, Homemakers' caregiving stress was positively correlated to their academic background and monthly income, but negatively correlated to perceived adequacy of human resources, perceived adequacy of material resource, psychical support resource from relatives, and internal locus of control. Second, caregiving stress of homemakers was affected by family cohesion, monthly income, psychical support resource from relatives, perceived adequacy of human resources, and external locus of control.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.145-148
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• 2002

In this paper, a voltage controlled oscillator (VCO) with automatic amplitude control is designed using a 0.35${\mu}{\textrm}{m}$ CMOS process. A cross-coupled PMOS pair is used for a negative resistance to compensate for the losses in the LC resonator, and an automatic\ulcorner amplitude control function is adapted to provide constant output power independent of the Q-factor of the LC resonator. The designed VCO operates in the 200MHz to 550MHz frequency range using different external resonators. The simulated phase noise is -128 dBc/Hz at 100KHz offset from the carrier frequency of 260MHz. It dissipates 0.㎽ from a 3V power supply. The area is 300${\mu}{\textrm}{m}$ x1201${\mu}{\textrm}{m}$.

• Journal of Korean Physical Therapy Science
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• v.21 no.1
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• pp.37-43
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• 2014

Background : The purpose of this study is to verify the type of influence on the skin color according to the photoaging symptoms depending on the degree of external activities among the factors that influence the skin due to UV exposure and to obtain the basic study data on the physical therapy of the skin. Methods : In this study, in order to investigate the type of influence on the skin color according to the photoaging symptoms when the body is exposed to the UV rays having various effects on our body, a study was conducted using questionnaires and skin color measurement tool targeting 20 male college soccer students with many external activities and the senior high school students who has relatively less external activities due to the preparation for college entrance. The skin color was measured and the results were compared. Result : In the test group having relatively higher external activities, while they had less use of the sunscreen, they had more degree of UV exposure, and for the recognition of ultraviolet hazard, more were aware that it was harmful. In addition, in the skin color measurement test conducted targeting the son and the father in order to investigate the association between the skin color and the genetic factors, the experimental group showed a significant difference(p<.05) but the control group did not show any significant difference(p>.05). Conclusion : Based on such study results, the UV exposure time and the use of sunscreen are thought to be an important factor in the skin care.

• Journal of Drive and Control
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• v.14 no.4
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• pp.37-44
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• 2017

This paper introduces a control algorithm for trajectory control of an electro-hydrostatic rotary actuator. A key feature of this paper is that an adaptive PID based on sliding mode is used to control the nonlinearity and uncertainty factor of single input/output system. Accurate knowledge of rotary actuator angle can result in high-performance and efficiency of electro hydraulic system. First, the position control is formulated using the adaptive PID with sliding mode technique and uncertainties in the hydraulic system. Second, the controller can update the PID gains on-line based on error caused by external disturbance and uncertain factors in the system. Finally, three experimental cases were studied to evaluate the proposed control method.

• Journal of Nutrition and Health
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• v.34 no.2
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• pp.222-229
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• 2001

This study describes the application of the stages of change construct to fat intake by examining the associations of the stages of change with nutritional status and beliefs on health behavior. Data were obtained from apparently healthy 596 adults(326 females and 270 males) residing in large cities. Stages of change assessed by an algorithms based on 6 items were designed each subject into one of the 5 stages: precontemplation(PC), contemplation(CO), preparation(PR), action(AC) and maintenance(MA). Beliefs on health behavior were assessed by self efficacy as well as 4 belief scales from the Locus of Illness Control(LIC) developed using factor analysis such as internal disease cure and prevention and external disease cure and prevention. Energy and fat intakes were measured by a 39 item short form food frequency questionnaire. Regarding the 5 stages of change, MA stage comprised the largest group(37.9%), followed by Ac(30.7%), PC(11.4%), CO(10.4%) and PR(9.6%). Subjects who were females, older or healthier were more likely to belong to either AC or MA. Stage assignment of individuals was corroborated by their nutritional variables. Those in PC had the most energy and fat and those in MA ate the least for females. BMI was higher in PR than any other stages for both males and females. Those in PC were distinctive in that they were more externally oriented in terms of health control showing higher scores on external disease prevention(for males) and external disease cure(for females), and lower score on internal disease cure. On the other hand, those in MA received the highest scores on internal disease prevention and self efficacy, which suggested that they were more internally oriented. Canonical discriminant function analysis indicated that the 5 stages were importantly discriminated by BMI, self efficacy, internal disease prevention and external disease prevention for males and by fat intake, self efficacy and external disease cure variables for females. The results of our study confirm differences in stages of change in fat intake in terms of nutritional status and beliefs on heath behavior and indicate the need for taking these phases of change into account in nutrition advice. (Korean J Nutrition 34(2) : 222-229, 2001)

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.5
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• pp.459-464
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• 2013

A reset-free anti-harmonic programmable multiplying delay-locked loop (MDLL) that provides flexible integer clock multiplication for high performance clocking applications is presented. The proposed MDLL removes harmonic locking problems by utilizing a simple harmonic lock detector and control logic, which allows this MDLL to change the input clock frequency and multiplication factor during operation without the use of start-up circuitry and external reset. A programmable voltage controlled delay line (VCDL) is utilized to achieve a wide operating frequency range from 80 MHz to 1.2 GHz with a multiplication factor of 4, 5, 8, 10, 16 and 20. This MDLL achieves a measured peak-to-peak jitter of 20 ps at 1.2 GHz.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.45-54
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• 2011

A vehicle suspension system performs two functions, the ride quality and the stability, which conflict with each other. Among the various suspension systems, an active suspension system has an external energy source, from which energy is always supplied to the system for continuous control of vehicle motion. In the process of the linearization for the nonlinear active suspension system, the frequency dependent damping method is used for the exact modelling to the real model. The pressure control valve which is controlled by proportional solenoid is the most important component in the active suspension system. The pressure control valve has the dynamic characteristics with 1st order delay. Therefore, It's necessary to adopt the lead compensator to compensate the dynamics of the pressure control valve. The sampling time is also important factor for the control performances. The sampling time value is proposed to satisfy the system performances. After the modelling and simulation for the pressure control valve and vehicle dynamic, the performances of the vehicle ride quality and the stability are enhanced.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.22-28
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• 2010

Approximate analysis for a building installed with a friction damper is performed to get insight of its dynamic behavior. Energy balance equation is used to have a closed analytical form solution of dynamic magnification factor(DMF). It is found out that DMF is dependent on friction force ratio and resonance frequency. Approximation of DMF and equivalent damping ratio of a friction damper is proposed with such assumption that the building with a friction damper shows harmonic steady-state response and narrow banded response behavior near resonance frequency. Linear transfer function from input external force to output building displacement is suggested from the simplified DMF equation. Root mean square of a building displacement is derived under earthquake-like random excitation. Finally, design procedure of a friction damper is proposed by finding friction force corresponding to target control ratio. Numerical analysis is carried out to verify the proposed design procedure.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.2
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• pp.145-154
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• 2023

In this study, to control the heading angle of a ship, which is constantly subjected to various internal and external disturbances during the voyage, an LADRC (linear active disturbance rejection control) design that focuses more on improving the disturbance removal performance was proposed. The speed rate of change of the ship's heading angle due to the turn of the rudder angle was selected as a significant factor, and the nonlinear model of the ship's maneuvering equation, including the steering gear, was treated as a total disturbance. It is the similar process with an LADRC design for the first-order transfer function model. At this time, the gains of the controller included in LADRC and the gains of the extended state observer were tuned to RCGAs (real-coded genetic algorithms) to minimize the integral time-weighted absolute error as an evaluation function. The simulation was performed by applying the proposed GA-LADRC controller to the heading angle control of the Mariner class vessel. In particular, it was confirmed that the proposed controller satisfactorily maintains and follows the set course even when the disturbances such as nonlinearity, modelling error, uncertainty and noise of the measurement sensor are considered.