• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.880-886
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• 2007

We have proposed a new "hybrid" envelope elimination and restoration(EER) transmitter architecture using an efficiency optimized power amplifier(PA) and modified bias modulator. The efficiency of the PA at the average drain voltage is very important for the overall transmitter efficiency because the PA operates mostly at the average power region of the modulation signal. Accordingly, the efficiency of the PA has been optimized at the region. Besides, the bias modulator has been accompanied with the emitter follower for the minimization of memory effect. A saturation amplifier, class $F^{-1}$ is built using a 5-W PEP LDMOSFET for forward-link single-carrier wideband code-division multiple-access(WCDMA) at 1-GHz. For the interlock experiment, the bias modulator has been built with the efficiency of 64.16% and peak output voltage of 31.8 V. The transmitter with the proposed PA and bias modulator has been achieved an efficiency of 44.19%, an improvement of 8.11%. Besides, the output power is enhanced to 32.33 dBm due to the class F operation and the PAE is 38.28% with ACLRs of -35.9 dBc at 5-MHz offset. These results show that the proposed architecture is a very good candidate for the linear and efficient high power transmitter.

• The Journal of Korean Academy of Sensory Integration
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• v.7 no.1
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• pp.27-36
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• 2009

Introduction : Occupational therapists commonly use clinical observation to assess neuromuscular function witch is a fundamental component of sensory integration function. Clinical Observation of Motor and Postural Skills (COMPS) is a standardized assessment with seven items and used to screen if a child's problem is due to neuromuscular and sensory integration system. However, developmental standard of the test need to be validated with Korean children. Objective : This study is purposed to propose developmental standard of the COMPS for Korean children. Method : Seven to nine years old students (76 male and 70 female) participated in this study. In order to find out any difference by gender and age, the data was analyzed using t-test and ANOVA. Results : There is no significant difference by gender for all other items except Prone Extension Position (PEP). There is significant difference between children who are 7 years old and those who are 9 years old for Slow Motion(SM), Finger-Nose Touching (FNT), Asymmetrical Tonic Neck Reflex (ATNR), Supine Flexion(SF). There is also significant difference between those who are 8 years old and 9 years old for SM, FNT, ATNR. However, there is no significant difference between those who are 7 years and 8 years old. Conclusions : This study examines any difference in neuromuscular characteristics by age among school-aged children, based on the COMPS. The result of this study will provide a good evidence to establish developmental standard of COMPS for Korean children. It issuggested to continue further standardization work of the COMPS in order to establish a developmental standard for Korean children.