• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.40-42
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• 2001

본 논문에서는 공유 저장장치 기반 클러스터 시스템의 평균 서비스 시간을 줄이기 위해서 클러스터 시스템의 연선 종류와 부하량에 따라 재구성 시점을 결정하는 적응적 자료 재구성 방식(Adaptive Data Reorganization)을 제안한다. 또한 클러스터 시스템에서 처리해야할 서비스가 없고 서비스 요청도 없을 때 자료 재구성을 수행하는 지연 재구성 방식(Deferred Reorganization)을 채택하였다. 자료 재구성 방식은 전체적인 자료 재구성과 부분적인 자료 재구성으로 나누어 실행된다. 또한 적응적 자료 재구성 방식을 통한 공유 저장장치 기반 클러스터 시스템의 성능 평가를 위해 마르코프 모델(Markov Model)을 사용한다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.387-388
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• 2017

Cascaded H-bridge 멀리레벨인버터는 출력전압 레벨 수를 증가시켜 고전압 응용이 가능하도록 하는 전력변환장치로 모듈화 특성이 우수하여 그 활용 범위를 넓혀가고 있다. 출력 전압레벨 수를 증가시켜 보다 정현파에 가까운 양질의 출력전압을 생성하기 위해서는 스위칭 소자와 입력 전압원 개수의 증가로 인해 회로구조와 제어방법이 복잡해지는 문제가 발생한다. 하지만 스위칭 여유율(Redundancy)에 따른 대체 스위칭 패턴의 적용으로 전체 시스템의 신뢰성을 개선시킬 수도 있다. 본 논문에서는 고장나무 분석을 통해 Cascaded H-bridge 멀티레벨 인버터의 위험도를 계산하고 스위칭 여유율과의 관련성을 분석하고자 한다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.30-31
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• 2006

In a multi-action tooling system, which is usually used for the powder compaction process to fabricate the complex multilevel parts, crack formation is crucially detrimental and should be avoided. Among various process factors, tool shape is an important factor to prevent the crack formation during powder compaction process. In this work, the effects of different tool shapes were investigated through the experimental oberservation of pore distribution in real products and the finite element analysis of residual stresses. The results were interpreted based on non-uniform powder density in the compacted parts.

• Perspectives in Nursing Science
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• v.15 no.2
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• pp.49-69
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• 2018

Purpose: The purpose of this study was to derive contextual indicators of medical provider quality and assess their relative importance along with the individual utilization of antenatal care (ANC) and institutional births with a skilled birth attendant (SBA) in India using a multilevel framework. Methods: The 2015~2016 Demographic and Health Survey (DHS) from India was used to assess the outcomes of neonatal, infant, and under-five child mortality. The final analytic sample included 182,980 children across 28,283 communities, 640 districts, and 36 states and union territories. The contextual indicators of medical provider quality for districts and states were derived from the individual-level number of ANC visits (<4 or ${\geq}4$) and institutional delivery with SBA. A series of random effects logistic regression models were estimated with a stepwise addition of predictor variables. Results: About half of the mothers (47.3%) had attended ${\geq}4$ ANC visits and 75.8% delivered in institutional settings with SBAs. Based on ANC visits, 276~281 districts (43.1~43.9%) and 13~16 states (36.5~44.4%) were classified as "low" quality areas, whereas 268~285 districts (41.9~44.5%) and 8~9 states (22.2~25.0%) were classified as "low" quality areas based on institutional delivery with SBAs. Conditional on a comprehensive set of covariates, the individual use of both ANC and SBA were significantly associated with all mortality outcomes (OR: 1.17, 95% CI: 1.08, 1.26, and OR: 1.10, 95% CI: 1.02, 1.19, respectively, for under-five child mortality) and remained robust even after adjusting for contextual indicators of medical provider quality. Districts and states with low quality were associated with 57~61% and 27~43% higher odds of under-five child mortality, respectively. Conclusion: When simultaneously considered, district- and state-level provider quality mattered more than individual access to care for all mortality outcomes in India. Further investigations are needed to assess the importance of improving the quality of health service delivery at higher levels to prevent unnecessary child deaths in developing countries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.104-115
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• 2016

Objective: This study was conducted in order to investigate the effects of individual patient behavior regarding the health and medical care level on their therapeutic compliance for people diagnosed with high blood pressure by a physician, in order to evaluate the impact of treatment compliance. In this study, the therapeutic compliance was defined as the hypertension drug cure rate. The current blood pressure controls were persons about 30 years of age diagnosed with high blood pressure by their doctor one month fraction of the people who take more than 20 days (30 days). Methods: The data was analyzed by using the X2-test for different comparisons of the therapeutic compliance in the individual characteristics and using a two-stage multilevel logistic regression to identify the community variance of the related index of high blood pressure therapeutic compliance using the data from 229 adults over the age of 19 in a community health survey conducted in 2010. The Spss 18.0 statistical program was used with HLM 7 (hierarchical linear model) Results: It was found that the rate of therapeutic compliance was affected by the individual health behavior and health and medical care levels. Conclusion: In this study, although the odds ratio of the variable region of the high level of health care, I was able Unlike previous studies and focuses on the personal level of variation found variations in the local health care level was a significant. More studies on multilevel analysis are needed in the future considering regional level data.

• Asian Spine Journal
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• v.12 no.6
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• pp.1010-1016
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• 2018

Study Design: Retrospective cohort study. Purpose: To report on spinal fusion assessment using computed tomography (CT) after adult spinal deformity (ASD) surgery using ultra-low dose recombinant human bone morphogenetic protein 2 (RhBMP-2). Overview of Literature: The reported dose of RhBMP-2 needed for successful spinal posterolateral fusion in ASD ranges from 10 to 20 mg per spinal level. This study reports the use of ultra-low dose of RhBMP-2 (0.07 mg per facet) to achieve spinal fusion in multilevel ASD surgery. Methods: Consecutive patients who underwent ASD surgery using ultra-low dose RhBMP-2 were recruited. Routine postoperative CT analysis for spinal fusion was performed by two spine surgeons. Inter-observer agreement was calculated for facet fusion (FF) and interbody fusion (IBF) at 6 and 12 months after the procedure. Results: Six consecutive ASD patients with a mean age of 62 years (28-72 years) were examined. Each patient received a total dose of 12 mg with an average dose of $0.69{\pm}0.2mg$ (0.42-1 mg) per single FF and $1.38{\pm}0.44mg$ (0.85-2 mg) for IBF. Total 131 FF and 15 IBF were examined in the study, with 88 FFs and nine IBFs being analyzed specifically at 6 months after the surgery. FF and IBF reported by surgeons A and B at 6 months were 97.7% vs. 91.9% FF, respectively (${\kappa}=0.95$) and 100% vs. 100% IBF, respectively (${\kappa}=1$). Two patients underwent longitudinal follow-up CT at 12 months, and the FF rates reported by surgeons A and B were 100% vs. 95.8%, respectively (${\kappa}=0.96$). Five out of nine facet (56%) non-unions were identified at the cross-links. The remaining four facet pseudarthrosis were noted at 1-2 spinal levels caudal to the cross-links. At the final clinical follow-up, there was no rod breakage, deformity progression, neurological deficit, or symptom recurrence. The Oswestry Disability Index improved by an average of $32.8{\pm}6.3$, while the mental component summary of the 36-item Short-Form Health Survey improved by an average of $4.7{\pm}2.1$, and physical component summary improved by an average of $10.5{\pm}2.1$. Conclusions: To our knowledge, this is the first study to report a CT that defined 92%-98% FF and 100% IBF using the lowest reported dose of RhBMP-2 in multilevel ASD surgery. The use of ultra-low dose RhBMP-2 reduces the RhBMP-2 related complications and healthcare costs.

• Health Policy and Management
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• v.32 no.4
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• pp.347-355
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• 2022

Background: Since November 2019, long-term care hospitals have been able to provide patients with discharging programs to support the elderly in the community. This study aimed to identify both patient- and hospital-level factors that affect successful community discharge from long-term care hospitals. Methods: A multilevel logistic regression model was performed using hospitals as a clustering unit. The dependent variable was whether a patient stayed in the community for at least 30 days after discharge from a long-term care hospital. As for the patient-level independent variables, an agreement between a patient and the family about discharge, length of hospital stay, patient category, and residence at discharge were included. The number of beds and the ratio of long-stay patients were selected for the hospital-level factors. The sample size was 1,428 patients enrolled in the discharging program from November 2019 to December 2020. Results: The number of patients who were discharged to the community and stayed at least for 30 days was 532 (37.3%). The intraclass correlation coefficient was 22.9%, indicating that hospital-level factors had a significant impact on successful community discharge. The odds ratio (OR) of successful community discharge increased by 1.842 times when the patients and their families agreed on discharge. The ORs also increased by 3.020 or 2.681 times, respectively when the patients planned to discharge to their own house or their child's house compared to those who didn't have a plan for residence at discharge. The ORs increased by 1.922 or 2.250 times when the hospitals were owned by corporate or private property compared to publicly owned hospitals. The ORs decreased by 0.602 or 0.520 times when the hospital was sized over 400 beds or located in small and medium-sized cities compared to less than 200 bedded hospitals or located in metropolitan cities. Conclusion: The results of the study showed that the patients' and their family's willingness for discharge had a great impact on successful community discharge and the hospital-level factors played a significant role in it. Therefore, it is important to acknowledge and support long-term care hospitals to involve active in the patient discharge planning process.

• Journal of Korean Academy of Nursing
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• v.44 no.2
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• pp.198-208
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• 2014

Purpose: This research was an empirical study designed to identify precursors and interaction effects related to nurses' patient identification behavior. A multilevel analysis methodology was used. Methods: A self-report survey was administered to registered nurses (RNs) of a university hospital in South Korea. Of the questionnaires, 1114 were analyzed. Results: The individual-level factors that had a significantly positive association with patient identification behavior were person-organization value congruence, organizational commitment, occupational commitment, tenure at the hospital, and tenure at the unit. Significantly negative group-level precursors of patient identification behavior were burnout climate and the number of RNs. Two interaction effects of the person-organization value congruence climate were identified. The first was a group-level moderating effect in which the negative relationship between the number of RNs and patient identification behavior was weaker when the nursing unit's value congruence climate was high. The second was a cross-level moderating effect in which the positive relationship between tenure at the unit and patient identification behavior was weaker when value congruence climate was high. Conclusion: This study simultaneously tested both individual-level and group-level factors that potentially influence patient identification behavior and identified the moderating role of person-organization value congruence climate. Implications of these results are discussed.

• Journal of IKEEE
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• v.23 no.4
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• pp.1140-1149
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• 2019

In general, there are various pulse width modulation(PWM) methods simply using the offset voltage injection in voltage source converter(VSC). In accordance with the AC side voltage synthesis method with the offset voltage, DC side voltage utilization factor in VSC is changed. Also, this can apply equally to the MMC system. In other words, if the DC side capacity of the high voltage DC(HVDC) transmission system is determined, the maximum reactive power which can be supplied to the AC side can be changed according to the applied output voltage synthesis method with the offset voltage. In this paper, the leg energy pulsation in MMC system according to the AC side output voltage synthesis method with offset voltage which several representative PWM are applied to are mathematically analyzed and compared with each other. Finally, the above results are verified by simulation emulating the 400MVA full-scale MMC system to determine the consistency of the mathematical analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.33-40
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• 1989

In the design of reinforced concrete framed structures, which consist of various design variables, the objective and the constraint functions are formulated in complicated forms. Usually iterative methods have been used to optimize the design variables. In this paper, multilevel formulation is adopted, and design variables are selected in reduced numbers at each level, to reduce the iterative cycle and to accelerate the convergence rate. At level 1, elastic analysis is performed to get the upper and lower bounds of the redistributed design moments due to inelastic behavior of the frame. Then the design moments are taken as design variables and optimized at level 2, and the sizing variables are optimized at level 3. The optimization of redistributed moments is performed using the design sensitivity obtained at the level 2, and force approximation technique is used to reflect the variation of design variables in the lower level to the upper level. The design variables are selected in reduced numbers at each level, and the optimization formulation is simplified effectively. A cost function is taken as the objective function, and the constraints of the stress of the structures are derived from BSI CP 110 following limit state theory. Numerical examples are included to prove the effectiveness of the developed algorithm.