• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.161-162
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• 2008

In this paper we design an irregular low-density parity-check (LDPC) code for a multi-input multi-output (MIMO) system. The considered MIMO system is minimum mean square error soft-interference cancellation (MMSE-SIC) detector. The MMSE-SIC detector and the LDPC decoder exchange soft information and consist a turbo iterative detection and decoding receiver. Extrinsic information transfer (EXIT) charts are used to obtain the edge degree distribution of the irregular LDPC code which is optimized for the input-output transfer chart of the MMSE-SIC detector. It is shown that the performance of the designed LDPC code is much better than that of conventional LDPC code optimized for the AWGN channel.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.2
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• pp.83-87
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• 2014

This paper introduces a refined opportunistic interference alignment (OIA) technique that uses minimum mean square error (MMSE) detection at the receivers in multiple-input multiple-output multi-cell uplink networks. In the OIA scheme under consideration, each user performs the optimal transmit beamforming and power control to minimize the level of interference generated to the other-cell base stations, as in the conventional energy-efficient OIA. The result showed that owing to the enhanced receiver structure, the OIA scheme shows much higher sum-rates than those of the conventional OIA with zero-forcing detection for all signal-to-noise ratio regions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.54-55
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• 2015

In this paper, we propose a method pursuing robustness in ad hoc network system when the CSI of interferers is unavailable. The non-parametric linear minimum mean square error filter is exploited to achieve large fraction of the MMSE filter transmission capacity employing the perfect covariance matrix information. From the numerical results, we show that the proposed scheme brings substantial transmission capacity gain over conventional MMSE filter using sample covariance matrix.

• MALSORI
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• no.60
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• pp.181-190
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• 2006

This paper describes a speech enhancement scheme that leads to significant improvements in recognition performance when used in the ASR front-end. The proposed approach is based on adaptive comb filtering and an MMSE-related parameter estimator. While adaptive comb filtering reduces noise components remarkably, it is rarely effective in reducing non-stationary noises. Furthermore, due to the uniformly distributed frequency response of the comb-filter, it can cause serious distortion to clean speech signals. This paper proposes an improved comb-filter that adjusts its spectral magnitude to the original speech, based on the speech absence probability and the gain modification function. In addition, we introduce the modified comb filtering-based speech enhancement scheme for ASR in mobile environments. Evaluation experiments carried out using the Aurora 2 database demonstrate that the proposed method outperforms conventional adaptive comb filtering techniques in both clean and noisy environments.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.35-35
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• 2004

• Korean Journal of Psychosomatic Medicine
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• v.22 no.2
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• pp.71-78
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• 2014

Objectives : Behavioral and psychological symptoms of dementia(BPSD) represent significant clinical problems, resulting in functional decline, caregiver distress, institutionalization and increased mortality. A recent study showed gender differences have important role in the development of BPSD, but relationship between BPSD and gender has never been studied in Korea. This study was designed to examine whether patients with Alzheimer's disease show gender differences in behavioral and psychological symptoms of dementia(BPSD). Methods : Ninety-eight subjects with Alzheimer's disease were included in this study. We carried out history taking and cognitive assessment for the diagnosis of Alzheimer's disease based on DSM-IV. Cognitive impairment and BPSD were measured using the Mini Mental State Examination(MMSE), Global Deterioration Scale (GDS), Clinical Dementia Rating(CDR) and the Korean Neuropsychiatric Inventory(K-NPI). Independent samples t-test was used to examine the differences across gender in BPSD. Correlation analysis between MMSE, CDR, GDS and NPI was performed using Pearson's correlation coefficient. Results : There were no significant gender differences between the gender in BPSD. We found statistically significant negative correlations between MMSE with NPI total score, and with scores of several sub-domains such as hallucination. Conclusions : This study showed that gender differences in BPSD are not significant. Further research is necessary to identify whether BPSD affect gender differences or individual differences.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.15-20
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• 2016

Compared to the MIMO system using the spatial multiplexing methods and the MIMO system using the diversity scheme achieved a high rate, but the lower the diversity gain to improve the data transmission reliability should separate the spatial stream at the MIMO receiver. In this paper, we compared Channel capacity detection methods with the Lattice code, the 3-user interference channel and linear channel interference detection methods ZF (Zero Forcing) and MMSE (Minimum Mean Square Error) detection methods. The channel is a Diagonal channel. In other words, Diagonal channel is confirmed by the inverse matrix satisfies the properties of Jacket are element-wise inverse to $[H]_N[H]_N^{-1}=[I]_N$.

• Journal of Oriental Neuropsychiatry
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• v.23 no.3
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• pp.99-116
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• 2012

Objectives : The purpose of this study is to evaluate the effects of Needle-Embedding Therapy on dementia patients. Methods : We recruited 3 dementia patients who have been experiencing memory disorder and orientation disorder. The patients had been evaluated with Mini-Mental State Examination-K (MMSE-K), Global Deterioration Scale (GDS) and Clinical Dementia Rating (CDR). The patients were treated with herbal medication (Sunghyangjunggi-san) and acupuncture. After 15 days, the patients were added to Needle-Embedding Therapy. We measured MMSE-K, GDS and CDR for every 15 days. The effects of additional Needle-Embedding Therapy were compared with the effects of acupuncture and herbal medicine. Results : After Needle-Embedding Therapy was added, Patients' memory and orientation have been improved and the score of MMSE-K ascended. The grade of GDS and CDR were maintained or decreased. Conclusions : This study suggests that Needle-Embedding Therapy is significantly effective on Dementia patients.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.86-87
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• 2011

본 논문에서는 상향링크 다중 사용자 MIMO-OFDM 시스템을 위한 새로운 자원 할당 기법을(resource allocation) 제안한다. 제안된 자원 할당 기법에서는 각 사용자별 전송전력 제한을 만족하면서 주파수 효율이(spectral efficiency) 최대화 되도록 사용자들에게 부반송파와(subcarrier) 전력을(power) 할당한다. 모의 실험 결과에서는 제안된 기법이 기존 기법에 비해 주파수 효율이 증가됨을 보이고 있다.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.267-275
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• 2020

Objectives: The causes of dementia have been reported in various ways, but there has been little research on the interrelationship between heavy metals and dementia, and the results also show little consistency. Therefore, it is imperative to compare the levels of heavy metal exposure between the dementia-suffering group and a control group to confirm the correlation between the level of heavy metal exposure and the likelihood of dementia. Methods: In order to assess the dementia level of the elderly, the Global Deterioration Scale (GDS) and Mini Mental State Examination (MMSE) were applied. To analyze the concentration of heavy metals in the blood, blood was collected from the veins of study subjects and measured using Inductively Coupled Plasma-mass spectrometry (ICP-MS). Results: There was a statistically significant correlation between lead and manganese concentrations in the blood and the MMSE and GDS. It was found that there was a statistically significant correlation between cadmium concentration in the blood and the GDS, but the MMSE was less relevant. It was found that the blood mercury concentration and the MMSE and GDS were less relevant. The lead concentration in the blood was 0.95±0.74 ㎍/dL in the dementia patient group and 0.33±0.22 ㎍/dL in the normal group, while cadmium was 0.69±0.37 ㎍/L in the dementia group and 0.18±0.10 ㎍/L in the normal group. Mercury was 0.81±0.31 ㎍/L in the dementia group and 1.16±0.80 ㎍/L in the normal group. Manganese was 6.83±2.01 ㎍/L in the dementia group and 4.78±1.59 ㎍/L in the normal group. All of these show statistically significant differences. Conclusions: As the concentration of lead, cadmium and manganese in the blood increases, the MMSE scores and GDS scores were found to worsen, and it was confirmed that there is a correlation between heavy metal exposure and cognitive degradation.