• Journal of Korean Neurosurgical Society
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• v.47 no.3
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• pp.191-198
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• 2010

Objective : This study is planned to determine the neurocognitive difficulties of hydrocephalic adults. Methods : The research group contained healthy adults (control group, n : 15), and hydrocephalic adults (n : 15). Hydrocephalic group consisted of patients with idiopathic aquaduct stenosis and post-meningitis hydrocephalus. All patients were followed with shunted hydrocephalus and not gone to shunt revision during last two years. They were chosen from either asymptomatic or had only minor symptoms without motor and sensorineural deficit. A neuropsychological test battery (Raven Standart Progressive Matrices, Bender-Gestalt Test, Cancellation Test, Clock Drawing Test, Facial Recognition Test, Line Orientation Test, Serial Digit Learning Test, Stroop Color Word Interference Test-TBAG Form, Verbal Fluency Test, Verbal Fluency Test, Visual-Aural Digit Span Test-B) was applied to all groups. Results : Neuropsychological assessment of hydrocephalic patients demonstrated that they had poor performance on visual, semantic and working memory, visuoconstructive and frontal functions, reading, attention, motor coordination and executive function of parietal lobe which related with complex and perseverative behaviour. Eventually, these patients had significant impairment on the neurocognitive functions of their frontal, parietal and temporal lobes. On the other hand, the statistical analyses performed on demographic data showed that the aetiology of the hydrocephalus, age, sex and localization of the shunt (frontal or posterior parietal) did not affect the test results. Conclusion : This prospective study showed that adult patients with hydrocephalus have serious neuropsychological problems which might be directly caused by the hydrocephalus; and these problems may cause serious adaptive difficulties in their social, cultural, behavioral and academic life.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.589-602
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• 2009

The phenomenon degrading reception performance of DVB broadcasting signal is caused by collocation of plural communication modules in the GSM-900 cellular phone with a built-in DVB-H receiver. This paper offers how to improve performance of the DVB-H receiver by applying digital filter that is using DSP techniques to cancel GSM signal interfering to the DVB-H receiver which is collocated in a single user's GSM terminal. In the demodulation part of the DVB-H receiver, the DVB reception performance can be greatly improved by removing interference components of GSM signal, which is flowed with DVB signal, to the noise cancellation filtering algorithm using difference of characteristics between GSM modulated signal and OFDM signal.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.107-113
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• 2009

In Digital On-Channel Repeaters (DOCR) of Terrestrial-DMB (Digital Multimedia Broadcasting), there exist feedback signals generated from transmit antenna and re-entering at receive antenna. Therefore DOCR becomes unstable unless the feedback signal is properly eliminated. Previous research proposed a feedback canceller to estimate the feedback channel to deal with this problem. However formerly used estimation algorithms show unsatisfied performance in terms of convergence rate and quality although their implementations are simple. This paper applies PNLMS (Proportionate Normalized Least Mean Squares) adaptive algorithm to feedback channel estimation and evaluates the performances which solve the problem of feedback signal effectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.177-182
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• 2007

This paper presents the InGaP/GaAs HBT differential LC VCO with low phase noise performance for adaptive feedback interference cancellation system(AF-lCS). The VCO is verified with enhanced tank structure including filtering technique. The output tuning range for proposed VCO using asymmetric inductor and symmetric capacitors withlow pass filtering technique is 207 MHz. The output powers are -6.68 including balun and cable loss. The phase noise of this VCO at 10 kHz, 100 kHz and 1 MHz are -102.02 dBc/Hz, -112.04 dBc/Hz and -130.40 dBc/Hz. The VCO is designed within total size of $0.9{\times}0.9mm^2$.