http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Peak-to-average power ratio in MIMO-OFDM systems using selective mapping
Yung-Lyul Lee,Young-Hwan You,Won-Gi Jeon,Jong-Ho Paik,Hyoung-Kyu Song IEEE 2003 IEEE COMMUNICATIONS LETTERS Vol.7 No.12
<P>This letter evaluates the peak-to-average power ratio (PAR) performance in a space-time block coded (STBC) multi-input multi-output orthogonal frequency-division multiplexing (MIMO-OFDM) system using the selective mapping (SLM) approach. The investigated SLM-based MIMO-OFDM system selects the transmitted sequence with the lowest average PAR over all transmit antennas and retrieves the side information very accurately at the expense of only 0.5-dB degradation of the PAR, which can improve the overall detection performance of the MIMO-OFDM system with erroneous side information, compared to the individual SLM approach.</P>
Sang-Lyul Ryu,Yeong-wha Sawng,Seunglak Park,Jayoun Won 한국무역학회 2021 Journal of Korea trade Vol.25 No.7
Purpose – This paper’s purpose is to investigate how foreign ownership and innovation affect firm value. Design/methodology – Firm innovation is defined as operational efficiency, which is calculated by adopting data envelopment analysis (DEA). Additionally, R&D intensity is included as a measure of innovation in the analysis. We used firm-level data from manufacturing companies in Korea. The sample comprised 3,753 firm-year observations for every year in the period 2003–2017. Findings – We found that foreign ownership and innovation are positively related to firm value (Tobin’s Q). Foreign ownership moderates innovation’s contribution to firm value, implying that foreign ownership may enhance the value relevance of firm innovation. In addition, we found that firm innovation partially mediates the relationship between foreign ownership and firm value. Originality/value – This highlights the important role of foreign investors’ monitoring; wherein foreign investors enhance firm value by facilitating firm innovation. Our results suggest that foreign ownership can be crucial for innovation and may serve to address weak ownership structures.
The Gender Difference in the Occupational Hazards and Injuries of Cleaning Workers and Janitors
Chang Lyul Choi 대한인간공학회 2017 大韓人間工學會誌 Vol.36 No.5
Objective: The purpose of this study is to analyze the accident characteristics according to the gender of the injured workers in building cleaning and to reflect them in the Industrial Accident Prevention Policy. Background: An analysis of industrial accidents is an essential process for establishing systematic industrial accident prevention measures. In order to establish industrial accident prevention measures for workers effectively, it is necessary to analyze accident characteristics by job type for workers who do the same work. Method: In this study, we analyzed the accident characteristics of 1,645 janitors who were approved of work-related injuries in 2015. We also analyzed the characteristics according to gender by dividing them into worker-related factors and accident-related factors. Results: The accidents caused to the janitors showed different characteristics according to gender, age, work experience, agency of accident, and distribution of original cause materials. In other words, 70.2% occurred to workers over 60 years old and 56.2% occurred to unskilled workers with less than a year of work experience. In the case of accident pattern, 79.1% occurred in tripping (slip) hazards, and 68.2% of accidents occurred on the floor (including the ground) and the stairs, indicating that the accident occurred most frequently during cleaning work on the floor or stairs. Conclusion and Application: The results of the study on the accident characteristics of the janitors can be used as basic data for systematic preventive measures against accidents occurring to the elderly female workers in the service industry.