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Search Results: 1 - 10 of 7648 matches for " Choongkoo Park "
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A Thyristor-Only Input ESD Protection Scheme for CMOS RF ICs  [PDF]
Jin Young Choi, Choongkoo Park
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.23025
Abstract: We propose an input protection scheme composed of thyristor devices only without using a clamp NMOS device in order to minimize the area consumed by a pad structure in CMOS RF ICs. For this purpose, we suggest low-voltage triggering thyristor protection device structures assuming usage of standard CMOS processes, and attempt an in-depth comparison study with a conventional thyristor protection scheme incorporating a clamp NMOS device. The comparison study mainly focuses on robustness against the HBM ESD in terms of peak voltages applied to gate oxides in an input buffer and lattice heating inside protection devices based on DC and mixed-mode transient analyses utilizing a 2-dimensional device simulator. We constructed an equivalent circuit for the input HBM test environment of the CMOS chip equipped with the input ESD protection devices. And by executing mixed-mode simulations including up to four protection devices and analyzing the results for five different test modes, we attempt a detailed analysis on the problems which can occur in real HBM tests. We figure out strength of the proposed thyristor-only protection scheme, and suggest guidelines relating the design of the protection devices and circuits.
The Finite-Element Modeling of Dynamic Motions of a Constraint Wind Turbine and the System Diagnosis for the Safety Control  [PDF]
Raiwung Park
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.512123
Abstract:

The aim of this paper is to present a finite element modeling of the dynamic motion of a turbine rotor and its controller design with the mass unbalance under a crack on a rotating shaft. This process is an advanced method to the mathematical description of a system including an influence of a mass unbalance and a crack on the rotor shaft. As the first step, the shaft is physically modeled with a finite element method and the dynamic mathematical model is derived by using the Hamilton principle; thus, the system is represented by various subsystems. The equation of motion of a shaft with a mass unbalance and a crack is established by adapting the local mass unbalance and stiffness change through breathing and gaping from the existence of a crack. This is a reference system for the given system. Based on a fictitious model for transient behavior induced from vibration phenomena measured at the bearings, an elementary estimator is designed for the safety control and detection of a mass unbalance on the shaft. Using the state estimator, a bank of an estimator is established to get the diagnosis and the system data for a controller.

The effect of individualized music on agitation for home-dwelling persons with dementia  [PDF]
Heeok Park
Open Journal of Nursing (OJN) , 2013, DOI: 10.4236/ojn.2013.36061
Abstract:

Purpose: The purpose of this study was to test the effect of individualized music on agitation for homedwelling patients with dementia. Method: One group pre-post test was used for research design and a total of 26 subjects participated in this study. Individualized music intervention was subjects’ listening to their preferred music for 30 minutes prior to peak agitation time twice a week for a total of four sessions. The subject’s agitation levels were measured for three different points: thirty minutes prior to listening to music, 30 minutes while listening to the music, and after listening to the music throughout the 4 sessions. To measure the agitation level, the modified CohenMansfield Agitation Inventory was used. A Paired ttest was used for data analysis. Results: Most subjects were female (73.1%), Caucasian (92.4%), Protestant (50%), and independent activity (53.8%). The mean of the subjects’ MMSE scores was 8.08 (8.17). The most favorite music types included country/western music (31.0%), religious music (26.9%), and big band (26.9%). Agitation level decreased while listening to the music compared to the baseline (t = 3.70, p < .001). Conclusion: The findings of this study would provide meaningful data to develop an individualized music intervention protocol to control agitation for homedwelling patients with dementia.

 

Partially Funded Social Security and Inter-Generational Distribution  [PDF]
Hyeon Park
Theoretical Economics Letters (TEL) , 2014, DOI: 10.4236/tel.2014.49107
Abstract: This paper introduces a parametric model of partially funded social security system and analyzes inter-generational distribution of consumption and welfare in an OLG general equilibrium. This paper specifically aims to examine the effects of transition toward more funded system on saving and capital accumulation. It is shown that an increase in intensity of fundedness increases capital accumulation unless the income effect from interest rate change outweighs other effects and negatively affects the total saving severely. By deriving closed form solutions for the variables, this paper finds that an increase in the intensity of fundedness increases saving but decreases consumption, when population growth rate is greater than the net return to capital. This paper also finds that for a partially funded system, an increase in tax rate increases public saving but reduces private saving unambiguously, while the effects on consumption and capital accumulation are not conclusive.
Difference in the Contents of Music Intervention to Control Agitation by Music Providers  [PDF]
Heeok Park
Open Journal of Nursing (OJN) , 2015, DOI: 10.4236/ojn.2015.58077
Abstract: Purpose: The purpose of this study was to compare the contents of music intervention studies between the music therapists and non-music therapists who endeavored to control agitation in patients with dementia, and to provide meaningful ideas to improve the music interventions by music providers. Method: This study is a review study by searching CINAHL, MEDLINE, and PsychINFO for the keywords, “agitation” and “music,” which are used in the searches. Results: A total of 30 studies of music intervention (7 studies about music therapists and 23 studies about non-music therapists) were included for the review. The studies about music therapists had a more reasonable sample size, variety of music activities, and comparison groups. The studies of non-music therapists were provided by nurses, researchers, recreational therapists, and trained nursing assistants and they provided music using background music at a scheduled time for care, such as mealtimes and bathing times. Conclusions: Studies on music interventions need to have a more rigorous research design, such as randomized controlled trials for the future studies. Furthermore, there is a need for multi-disciplinary music intervention studies by music providers who have different types of educational backgrounds and clinical experiences.
Fluid-Structure Interaction Analysis for Drug Transport in a Curved Stenotic Right Coronary Artery  [PDF]
Seungman Park
Journal of Biosciences and Medicines (JBM) , 2016, DOI: 10.4236/jbm.2016.45011
Abstract: A blockage of blood vessels resulting from thrombus or plaque deposit causes serious cardiovascular diseases. This study developed a computational model of blood flow and drug transport to investigate the effectiveness of drug delivery to the stenotic sites. A three-dimensional (3D) model of the curved stenotic right coronary artery (RCA) was reconstructed based on the clinical angiogram image. Then, blood flow and drug transport with the flexible RCA wall were simulated using the fluid structure interaction (FSI) analysis and compared with the rigid RCA wall. Results showed that the maximal total displacement and von Mises stress of the flexible RCA model are 2.14 mm and 92.06 kPa. In addition, the effective injecting time point for the best performance of drug delivery was found to be between 0 s and 0.15 s (i.e., the fluid acceleration region) for both rigid and flexible RCA models. However, there was no notable difference in the ratio of particle deposition to the stenotic areas between the rigid and flexible RCA models. This study will be significantly useful to the design of a drug delivery system for the treatment of the stenotic arteries by targeting drugs selectively to the stenotic sites.
Willingness to Pay for the Subscription Fee of Public Broadcasting System  [PDF]
Inho Park, Hyun Soon Park
Advances in Journalism and Communication (AJC) , 2014, DOI: 10.4236/ajc.2014.21001
Abstract: The study aims at developing communication strategies for the public broadcasting system according to WTP (Willingness to Pay) for the subscription fee and the audience’s perception of the public broadcasting system as a public good. A quasi-experiment was conducted for audiences who have previously watched public broadcasting channels. According to the results, those respondents who think of public broadcasting as a public good and who think that public broadcasting performs its public role well have high intention to pay the subscription fee. Respondents feel at a loss when they pay the subscription fee, and the willingness to pay the fee goes down.
A Brief Review: Stage-Convertible Power Amplifier Using Differential Line Inductor  [PDF]
Jonghoon Park, Changhyun Lee, Changkun Park
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.34027
Abstract: In this review article, a stage-convertible RF power amplifier designed with a 0.18-μm RF CMOS process is described. A method to implement a low-power matching network is an essential technology for the stage-convertible power amplifier. Various low-power matching networks with distributed active transformers as an output power combiner are compared in terms of the amounts of undesired coupling, the chip size, and the amount of power loss. The feasibility of a differential line inductor for the stage-convertible power amplifier is assessed and explained. Finally, we show that the differential line inductor is a realistic means of reducing the overall chip size, enhancing the quality factor of the matching network, and minimizing the undesired coupling between the inter-stage matching network and any output matching network. Additionally, the operating mechanism of the stage-convertible power amplifier using the differential line inductor for a low-power matching network is described in detail.
Knowledge, Health Beliefs and Screening Status of Prostate Cancer among Middle-Aged and Elderly Men  [PDF]
Eunjoo Lee, Youngsuk Park, Jeongsook Park
Open Journal of Nursing (OJN) , 2016, DOI: 10.4236/ojn.2016.69070
Abstract: Purpose: The aim of this study was to examine and evaluate the level of prostate cancer knowledge and health beliefs among middle-aged and elderly men. Methods: In this descriptive study carried out in December 20, 2015 through January 20, 2016, we enrolled 147 men aged 50 - 70 years old. Data were collected by using three questionnairs including knowledge, health beliefs, and screening status of prostate cancer. Results: Our findings showed that only 20.4% of interviewers had experience of digital rectal examination or prostatic specific antigen test for prostate cancer screening. The prostate cancer knowledge was found to be significantly high in prostate cancer examinees compared to non-examinees. The correct answer rate of prostate cancer knowledge was only 44.7% at average. Despite of good perceived seriousness about prostate cancer, the screening rate was only 20.4% and the examinees indicated significantly high perceived sensitivity compared to non-examinees. The level of the perceived barrier was lower in men who had experience in health examination or prostate cancer examination than without experience. Conclusion: The significant factors including age, educational level, income and cancer insurance status need to be considered in nursing education program in order to deliver accurate knowledge about prostate cancer. Also, the effective interventions are necessary to increase sensitivity and reduce barriers of prostate cancer and screening.
On the Torsion Subgroups of Certain Elliptic Curves over Q  [PDF]
Yoon Kyung Park
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.32043
Abstract:

Let E be an elliptic curve over a given number field . By Mordells Theorem, the torsion subgroup of E defined over Q is a finite group. Using Lutz-Nagell Theorem, we explicitly calculate the torsion subgroup E(Q)tors for certain elliptic curves depending on their coefficients.

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