• Title/Summary/Keyword: Multilevel Approach

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A Multilevel Approach to Sibling Warmth and Conflict among Korean Young Adults by Gender: Roles of Sibling and Parent-Child Characteristics (청년의 형제자매 온정 및 갈등 관련 요인 성별 다층모형 분석: 형제자매 및 부모자녀 특성을 중심으로)

  • Yeseul Baek;Jaerim Lee
    • Human Ecology Research
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    • v.61 no.3
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    • pp.319-333
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    • 2023
  • The purpose of this study was to examine which sibling and parent-child characteristics were associated with siblisng warmth and conflict among Korean young adults. The data came from an online survey of Koreans aged 19-34 years who had at least one sibling and two living parents. We conducted a multilevel regression analysis using data from 193 men with 305 siblings and 203 women with 286 siblings. The results showed that, for men, the levels of warmth were higher when the sibling was younger, when they received more frequent financial and instrumental support from the sibling, and when maternal favoritism was relatively lower. Women reported higher levels of warmth when the sibling was a sister, when they provided more frequent support for the sibling, when they had a more affectionate relationship with the mother, and when paternal favoritism was lower. As for sibling conflict, the number of siblings was positively associated with the levels of conflict among both men and women. Maternal affection was negatively related with conflict for men, and paternal favoritism was positively related to conflict for women. Interestingly, women's sibling warmth and conflict were both higher when the sibling was a sister, which meant that relationships between sisters tended to be ambivalent. This study contributes to our understandings of Koreans' sibling relationships in young adulthood.

An Empirical Study on Factor Associated with Mood Disorders in Elderly: Focusing on the Influence of Community Characteristics (노인 기분장애 영향요인에 관한 실증적 연구: 지역사회 특성의 영향을 중심으로)

  • Chang, Miseung;Shim, Ik Sup
    • Health Policy and Management
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    • v.27 no.2
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    • pp.177-185
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    • 2017
  • Background: The mental problems of the elderly are at issue as a serious social phenomenon. The purpose of this study is to identify risk factors affecting the mood disorders of the elderly. Methods: The subjects were 1,779,236 aged ${\geq}65$ and participated in health screening. Dependent variable was mood disorders. Independent variables were consisted of community level (regional deprivation index and healthcare resources) and individual level (sex, age, insurance type, disability, smoking, alcohol, physical activity, body mass index, and healthcare utilization). Multilevel logistic regression was performed. Results: At the individual level, women, employed insured, severely disabled people, heavy alcohol drinkers, high-intensity physical activity, body mass index, and patients who had chronic disease and severe disease were significantly associated with mood disorders. As the age has increased, it has let increase of mood disorders. At the community level, as the regional deprivation index has increased by 1, mood disorders has been increased by 1.005 times. The intra-class coefficient was 7.04%. Conclusion: We found individual and community level factors are associated with mood disorders. Systematic approach is essential to reduce mood disorders.

Harmonic Analysis and Output Filter Design of NPC Multi-Level Inverters (NPC 멀티레벨 인버터의 고조파 분석 및 출력 필터 설계)

  • Kim, Yoon-Ho;Bang, Sang-Seok;Kim, Kwang-Seob;Kim, Soo-Hong
    • The Transactions of the Korean Institute of Power Electronics
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    • v.11 no.2
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    • pp.135-141
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    • 2006
  • In this paper, LC output filters are designed to reduce output harmonics and harmonic analysis are peformed. Generally, multilevel inverters are used in high power application and operates with low switching frequency, which, in turn, generates large output harmonics. Output filters we used to reduce output harmonics. The design approach to reduce output harmonics of the 31eve1 multilevel inverter is discussed and DSP(TMS320C31) is used for the digital control of the system. The design example is given. The designed system is verified by simulation and experiment.

Multilevel Inverter Development to Utilize Renewable Energy in Urban Railway Station (도시철도 역사 신재생에너지 활용을 위한 멀티레벨 인버터 개발)

  • Shin, Seungkwon;Kim, Hyungchul;Jung, Hosung;Park, Jong Young;Hyun, Byungsoo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.2
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    • pp.324-330
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    • 2015
  • Energy Saving Methods in existing railway vehicle are considered by active approach such as regenerative energy storage and utilization, eco driving, etc. On the other hands, energy saving measures in railway station are operated by passive method such as reduction of operating time in ventilation system, cooing system and power equipment. To reduce energy and for independence in railway system, it requires an active energy saving measures. It needs to its own power source besides the power source of electric supply company such as renewable energy and regenerative energy and take the advantage of power storage system and stored power are used in optimum time. This paper deal with 3-level NPC inverter and T-type NPC inverter that used in various multi-level topology applicable to the railway system.

LC Trap Filter Design of Single Phase NPC Multi-Level PWM Inverters for Harmonic Reduction (고조파 저감을 위한 단상 NPC 멀티레벨 PWM 인버터의 LC트랩 필터 설계)

  • Kim, Yoon-Ho;Lee, Jae-Hak;Kim, Soo-Hong
    • The Transactions of the Korean Institute of Power Electronics
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    • v.11 no.4
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    • pp.313-320
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    • 2006
  • In this paper, a design approach of LC trap filter for output side harmonic reduction of single phase NPC multilevel inverter is proposed, and THD of the output voltage and harmonic FFT of the output current are analyzed. The proposed filter consists of a conventional LCR filter cascaded with an LC trap filter and it is tuned to inverter switching frequency. A NPC multilevel inverter inverter is used an inverter system for high power application and DSP(TMS320C31) is used for the controller. The effectiveness of the proposed system confirmed through simulation and experimental results.

Improved Estimation Method for the Capacitor Voltage in Modular Multilevel Converters Using Distributed Neural Network Observer

  • Mehdi Syed Musadiq;Dong-Myung Lee
    • Journal of IKEEE
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    • v.27 no.4
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    • pp.430-438
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    • 2023
  • The Modular Multilevel Converter (MMC) has emerged as a key component in HVDC systems due to its ability to efficiently transmit large amounts of power over long distances. In such systems, accurate estimation of the MMC capacitor voltage is of utmost importance for ensuring optimal system performance, stability, and reliability. Traditional methods for voltage estimation may face limitations in accuracy and robustness, prompting the need for innovative approaches. In this paper, we propose a novel distributed neural network observer specifically designed for MMC capacitor voltage estimation. Our observer harnesses the power of a multi-layer neural network architecture, which enables the observer to learn and adapt to the complex dynamics of the MMC system. By utilizing a distributed approach, we deploy multiple observers, each with its own set of neural network layers, to collectively estimate the capacitor voltage. This distributed configuration enhances the accuracy and robustness of the voltage estimation process. A crucial aspect of our observer's performance lies in the meticulous initialization of random weights within the neural network. This initialization process ensures that the observer starts with a solid foundation for efficient learning and accurate voltage estimation. The observer iteratively updates its weights based on the observed voltage and current values, continuously improving its estimation accuracy over time. The validity of proposed algorithm is verified by the result of estimated voltage at each observer in capacitor of MMC.

A New Approach for Detection of Gear Defects using a Discrete Wavelet Transform and Fast Empirical Mode Decomposition

  • TAYACHI, Hana;GABZILI, Hanen;LACHIRI, Zied
    • International Journal of Computer Science & Network Security
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    • v.22 no.2
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    • pp.123-130
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    • 2022
  • During the past decades, detection of gear defects remains as a major problem, especially when the gears are subject to non-stationary phenomena. The idea of this paper is to mixture a multilevel wavelet transform with a fast EMD decomposition in order to early detect gear defects. The sensitivity of a kurtosis is used as an indicator of gears defect burn. When the gear is damaged, the appearance of a crack on the gear tooth disrupts the signal. This is due to the presence of periodic pulses. Nevertheless, the existence of background noise induced by the random excitation can have an impact on the values of these temporal indicators. The denoising of these signals by multilevel wavelet transform improves the sensitivity of these indicators and increases the reliability of the investigation. Finally, a defect diagnosis result can be obtained after the fast transformation of the EMD. The proposed approach consists in applying a multi-resolution wavelet analysis with variable decomposition levels related to the severity of gear faults, then a fast EMD is used to early detect faults. The proposed mixed methods are evaluated on vibratory signals from the test bench, CETIM. The obtained results have shown the occurrence of a teeth defect on gear on the 5th and 8th day. This result agrees with the report of the appraisal made on this gear system.

A Multilevel Project-Oriented Risk-Mining Framework for Overseas Construction Projects

  • Son, JeongWook;Lee, JeeHee;Yi, June-Seong
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.39-40
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    • 2015
  • As international construction market increases, the importance of risk management in international construction project is emphasized. Unfortunately, current risk management practice does not sufficiently deal with project risks. Although a lot of risk analysis techniques have been introduced, most of them focus on project's external unexpected risks such as country conditions and owner's financial standing. However, because those external risks are difficult to manage and take preemptive action, we need to concentrate on project inherent risks. Based on this premise, this paper proposes a project-oriented risk mining approach which could detect and extract project risk factors automatically before they are materialized. This study presents a methodology regarding how to extract potential risks which exist in owner's project requirements and project tender documents using state of the art data analysis method such as text mining. The project-oriented risk mining approach is expected to effectively reflect project characteristics to the project risk management and could provide construction firms with valuable business intelligence.

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A Hierarchical Approach for Design Analysis and Optimization of Framed Structures (프레임 구조의 계층적 설계 해석 및 최적화)

  • Hwang, Jin Ha;Lee, Hak Sool
    • Journal of Korean Society of Steel Construction
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    • v.12 no.1 s.44
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    • pp.93-102
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    • 2000
  • Substructuring-based hierarchical approach for design analysis and optimization of structural frames is presented in this study. The conceptual framework of this method is in the hierarchical modeling for design processes as well as structural systems and the methodology combining substructuring analysis and multilevel optimization. Mathematical models for analysis and synthesis are established on the common basis of substructuring systems. Modularized behavioral analysis, design sensitivity analysis and optimization are linked and integrated on the mathematical and structural basis of substructuring. Substructures are coordinated with the active constraints for system level and the weight ratio criteria. Numerical examples for test frames show the validity and effectiveness of the present approach.

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The 4th Industrial Revolution's Impact on Network Marketing - Focused on ABN Korea Case - (4차 산업혁명 시대 정보통신기술(ICT)이 가져온 네트워크 마케팅의 현재와 미래 - 한국암웨이 사례 연구 -)

  • Park, So-Jin;Oh, Chang-Gyu
    • The Journal of Information Systems
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    • v.26 no.4
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    • pp.379-400
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    • 2017
  • Purpose The purpose of this study is to investigate the effects of ICT on multilevel marketing organizations (MLMs) whose members are both salespeople and consumers. This study explores the effects of the latest ICT convergence on the direct selling, which is the oldest sales method, and suggests the direction for the development of network marketing. Therefore, we will propose the changes in direct sales brought by ICT and predict the future direction of network marketing in preparation for the 4th Industrial Revolution era. Design/methodology/approach Exploratory case study was the methodology selected for this paper. The case study enables the use of multiple methods for data collection and analysis. This study applies qualitative case-study methodology on Amway Korea, which is the top seller of MLM organizations, to better understand the impact of ICT. This study conducted an in-depth interview with four different levels of MLM members (e.g. membership, ruby, emerald, diamond) which are based on the qualification system of MLM organizations and observed their behaviors. Findings This study revealed that the ICT impact on network marketing organizations(MLMs) could be summarized as follows : new membership growth, easier communication with customers, increase in work efficiency, increase in organizational trust, change in educational environment, and increase in the use of social media. Based on the interview, we propose the changes of network marketing organizations in the fourth industrial revolution era and the future strategy of Amway Korea as follows: (1) retention of royal ABOs, (2) harmony with SMEs, (3) utilization of Big Data, (4) creation of IoT business model, and (5) construction of successful O2O business platform.