• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1678-1685
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• 2015

We propose a linear precoding scheme combining the merits of beamforming and orthogonal space-time block coding based on the imperfect CSI without knowing the CSI reliability. We first investigate the impact of the CSI reliability on precoding performance by assuming various values of the CSI reliability. Then, we propose a method of predicting the CSI reliability based on the received SNR for the design of an efficient precoder. We show the efficiency of the proposed scheme by simulation.

• Journal of Korean Academy of Nursing
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• v.52 no.2
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• pp.228-243
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• 2022

Purpose: The study aimed to translate the Couple Satisfaction Index (CSI 32) into Korean, to evaluate the reliability and validity of CSI 32 and short-form (CSI 16, 4) in the Korean context, and to determine a cut-off score for Korean couples. Methods: Korean Versions of the Couple Satisfaction Index (K-CSI) 32 was translated, back-translated, and reviewed by five bilingual experts. Confirmatory factor analysis (CFA) was conducted with data from a sample of 218 couples (N = 436) to test construct validity. Validity and reliability were evaluated. The receiver's operating characteristics curve analysis was used to obtain the cut-off score. Results: The construct validities of K-CSI 32, 16, and 4 were verified using one-factor structures. The results of CFA showed a slightly better fit for K-CSI 16 and 4 than for K-CSI 32. Convergent validity was supported by significant positive correlations of K-CSI with Kansas Marital Satisfaction Scale, Dyadic Adjustment Scale, and Family Relationship Assessment Scale. Moreover, the significant differences in K-CSI between normal and depressive group demonstrated known-group validity. Cut-off scores of 105.5 on K-CSI 32, 50.25 on K-CSI 16, and 13.25 on K-CSI 4 were validated to identify distressed couple relationships. Conclusion: For clinical practice, the reliable and valid K-CSI 32 has the potential to measure changes in couple satisfaction after couple therapy or interventions. Applying K-CSI 32 may facilitate research on couple and family relationships in nursing and contribute to the discussion on the role of couple satisfaction in mental health.

• Korean Journal of Social Welfare
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• v.59 no.4
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• pp.83-109
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• 2007

Client satisfaction has been getting more attention in the field of social work in Korea. However, there have been very few standardized tools to measure the construct. The purpose of this study is to develop the Korean version of the Client Satisfaction Inventory developed by McMurtry and Hudson. This study was conducted with a total of 259 clients of 6 social service agencies in Seoul metropolitan areas. Based upon the results of factor analysis, the Korean version of the Client Satisfaction Inventory(CSI-K) is considered a two-factor measure. The alpha coefficients of the subscales of the CSI-K are .964 and .885 which are considered very high. The subscales are significantly correlated with convergent variables and very weakly correlated with discriminant variables. It is suggested that scales more suitable for social work settings in Korean be developed.

• Journal of Korean Academy of Nursing
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• v.50 no.5
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• pp.671-685
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• 2020

Purpose: The purpose of this study was to develop a Coping Scale for Infertility-Women (CSI-W). Methods: The initial items were based on an extensive literature review and in-depth interviews with seven infertile women. Forty-three items were derived from a pilot survey. Data were collected from 216 women who had experienced intrauterine insemination (IUI) and in-vitro fertilization (IVF) more than once. The data were analyzed to verify the reliability and validity of the scale. Results: Seven factors containing 28 items (four factors containing 17 items for active coping and three factors containing 11 items for passive coping) were extracted from the exploratory factor analysis to verify the construct validity. The four factors of active coping were confrontation, self-control, seeking social support (spouse), and seeking social support (colleagues and experts). The three factors of passive coping were distancing, escape, and avoidance. These items were verified through convergent, discriminant, and concurrent validity testing. The internal consistency reliability was acceptable (active coping: Cronbach's α = .78; passive coping: Cronbach's α = .81). Conclusion: As its validity and reliability have been verified through various methods, the CSI-W can contribute to assessing the coping strategies of infertile women.

• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.85-97
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• 2003

There are various methods to assess to company's outcome. Among them, the customers satisfaction, which is assessed by customers, is the most important. If the customers satisfaction is measured by the CSI based on the proper reliability and validity, you can apply the result for various marketing methods. Therefore, this study develops a model to assess CSI for an industry, specifically, local automotive industry based on the SEM that is already proven valid through assessing models such as ACSI, KCSI and NCSI. Moreover, this research can be utilized for marketing strategy helping customers to decide as an AHP model, one of the decision making method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12A
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• pp.1182-1188
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• 2006

Adaptive OFDM(Orthogonal Frequency Division Multiplexing) improves data capacity and system performance over multipath fading by adaptively changing modulation schemes according to channel state information(CSI). To achieve a good performance in adaptive OFDM systems, CSI should be transmitted from receiver to transmitter in real time through feedback channel. However, practically, the CSI feedback delay d which is the sum of the data processing delay and the propagation delay is not negligible and damages to the reliability of CSI such that the performance of adaptive OFDM is degraded. This paper presents an adaptive OFDM system with a multistep predictor on the frequency axis to effectively compensate the multiple feedback delays $d(\geq2)$. Via computer simulation we compare the proposed scheme and existing adaptive OFDM schemes with respect to data capacity and system performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5305-5321
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• 2016

In wireless communication, the multiple-input multiple-output (MIMO) system is a well-known approach to improve the reliability as well as the data rate. In MIMO systems, channel state information (CSI) is typically required at the receiver to detect transmitted signals; however, in practical systems, the CSI is imperfect and contains errors, which affect the overall system performance. In this paper, we propose a novel maximum likelihood (ML) scheme for MIMO systems that is robust to the CSI errors. We apply an optimization method to estimate an instantaneous covariance matrix of the CSI errors in order to improve the detection performance. Furthermore, we propose the employment of the list sphere decoding (LSD) scheme to reduce the computational complexity, which is capable of efficiently finding a reduced set of the candidate symbol vectors for the computation of the covariance matrix of the CSI errors. An iterative detection scheme is also proposed to further improve the detection performance.

• 전기의세계
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• v.30 no.1
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• pp.41-46
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• 1981

In the current source inverters (CSI), which are widely used recently in many applications, in order to reduce the harmonic contents in the output line current, twelve-step waveform is synthesized usually by a phase-shifted addition of the output currents of two single CSI's. In this paper a new method of synthesis of the 12-step current waveform is suggested which employes a main and a new auxiliary inverters having lower capacity, and thus is economically advantageous over the conventional scheme. DC-side commutation and energy rebond circuit as described in Part I are also employed in this proposed twelve-step CIS for effective commutation and high reliability. Experimental results are also given in oscillgrams.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.508-515
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• 2003

There are various methods to assess to company's outcome. Among them, the customers satisfaction, which is assessed by customers, is the most important. If the customers satisfaction is measured by the CSI based on the proper reliability and validity, you can apply the result for various marketing methods. Therefore, this study develops a model to assess CSI for an industry, specifically, local automotive industry based on the SEM that is already proven valid through assessing models such as ACSI, KCSI and NCSI. Moreover, this research can be utilized for marketing strategy helping customers to decide as an AHP model, one of the decision making method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.580-592
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• 2012

In this paper, a new compressive feedback (CF) scheme based on distributed compressed sensing (DCS) for time-corrected MIMO channel is proposed. First, the channel state information (CSI) is approximated by using a subspace matrix, then, the approximated CSI is compressed using a compressive matrix. At the base station, the approximated CSI can be robust recovered with simultaneous orthogonal matching pursuit (SOMP) algorithm by using forgone CSIs. Simulation results show our proposed DCS-CF method can improve the reliability of system without creating a large performance loss.