231,191 research outputs found
Min Lee
No full text학위논문(박사)--아주대학교 일반대학원 :전자공학과,2014. 8List of Figures
Abbreviation
1 Introduction
1.1 Background and Motivation
1.2 Contributions
2 Closed-form Ergodic Cooperative Capacity for CoMP Joint Diversity Transmission
2.1 CoMP JDTN Model and Capacities
2.2 PDF of Instantaneous DC-SNR
2.3 Closed-form ECC
2.4 Proof of Theorem 2.1
2.5 ECC Behaviors
3 Joint Power Allocation for Ergodic Cooperative Capacity Maximization
3.1 CoMP JDTN Model
3.2 Problem Formulation and Optimum Power Allocation
3.3 JPA for Co2P JDT under Unity TCPP
3.4 JPA for Co2P JDT under Non-unity TCPP
3.5 JPA for Co3P JDT
3.6 Numerical Results
4 Approximations for Ergodic Capacities in Rayleigh fading Channels
4.1 Approximations for EC of a Single-branch Rayleigh-faded Channel
4.2 Approximation for ECC of Two-branch Rayleigh-faded Channels at the Balanced Point
4.3 Approximation for ECC of Three-branch Rayleigh-faded Channels at the Balanced Point
5 Joint Power Allocation for Total Coordination Point Power Minimization
5.1 Problem Formulation and Optimum Power Allocation
5.2 Approximated Expressions of JPA for Co2P JDT
5.3 JPA for Co2P JDT using Duality Condition
5.4 JPA for Co3P JDT using Duality Condition
5.5 Numerical Results
6 Conclusions
ReferencesDoctoralIn this dissertation, we study a coordinated multi-point (CoMP) joint diversity transmission network (JDTN) in Rayleigh fading channels.
First, as a useful tool to analyze the performance of the CoMP JDTN, we derive a closed-form ergodic cooperative capacity (ECC) expression of the CoMP JDTN in Rayleigh fading channels. To obtain the closed-form ECC expression, we first derive a closed-form probability density function (PDF) of the instantaneous diversity-combined signal-to-noise ratio, and then a closed-form ECC expression for the CoMP JDTN by using the derived closed-form PDF.
Second, using the closed-form ECC expression, we deal with the joint power allocation (JPA) problem for the CoMP JDTN with the constraint on the total coordination point power (TCPP), aimed at maximizing the ECC in Rayleigh fading channels. We first consider the coordinated two-point (Co2P) JDTN that consists of two coordinated transmission points (CTPs) - CTP1 and CTP2 - and a user equipment, under the unity TCPP. We obtain the relationship that yields the optimum CTP1 power with respect to the mean branch gain-to-noise ratios (GNRs). Then, we introduce two simple log-linear approximated (LLA) expressions for the optimum CTP1 power, with exact slope and approximated slope, respectively, at the balanced point. Using the LLA expressions, we also draw efficient criteria for turning off Co2P joint diversity transmission (JDT). Next, we extend the JPA problem to the case of a non-unity TCPP constraint. We furthermore introduce more accurate log-quadratic approximated (LQA) expressions for obtaining the CTP powers. Then, we extend our study to a coordinated three-point (Co3P) JDTN. Given the mean branch GNRs, we obtain a LLA expression for obtaining the optimum power of the third CTP (i.e., the worst quality-providing CTP). After obtaining the third-CTP power, we obtain the CTP powers of the two better quality-providing CTPs by invoking the LLA CTP power expressions for Co2P JDT power allocation, under the remaining power that is given by the TCPP minus the third-CTP power.
Finally, we deal with the JPA problem for the CoMP JDTN with an ergodic rate requirement in Rayleigh fading channels, aimed at minimizing the TCPP. Prior to the JPA problem for minimizing the TCPP in the CoMP JDTN, we present several approximate expressions for the EC of a single-branch Rayleigh-faded channel and the ECC of cooperative-branch Rayleigh-faded channels. Next, for the Co2P JDTN, we derive an optimality-conserving condition for the optimum CTP powers. We present two simple expressions such as a LLA expression for optimum CTP1 power and a LQA expression for optimum CTP2 power. Then, we present an improved JPA method for the Co2P JDTN, which can maintain the TCPP at an almost optimum level for the ergodic rate requirement. In this improved method, we obtain a much better TCPP approximation to give the required ergodic rate by using the linear interpolation of two known nearby sets of TCPP versus the ergodic rate. Using the TCPP approximation, we then obtain two CTP powers by using the LQA and LLA CTP power expressions of Co2P JDT for ECC maximization under the TCPP constraint. We further extend this method to the Co3P JDTN according to the similar process to that in the Co2P JDTN
Min-Jeong Lee
No full text학위논문(석사)--아주대학교 일반대학원 :의학과,2014. 8“신대체요법을 언제 시작해야 하는가?”란 물음에 답하는 것은 어려운 일이다. 신대체요법이 임박한 말기신장질환 환자에서 언제 투석을 시작할지에 대한 결정을 돕기 위하여, 본 연구에서는 한국 3차 의료기관에서 혈액투석 시작 시점에서의 말기신장질환 환자의 임상적 특징을 분석하고자 한다. 2010년 1월부터 2012년 12월까지 처음 혈액투석을 시작한 409명의 환자를 후향적으로 분석하였다. 말기신부전의 가장 흔한 원인은 당뇨병성신증 (48.7%) 였으며, 두 번째로 흔한 원인은 조직검사로 증명된 사구체신염 (11.7%)이었다. 혈액투석 시작 시점에서의 사구체 여과율은 5.59 ~ 7.82 ml/min/1.73m2 였다 (Nankivell equation 으로 계산한 사구체 여과율 제외). 이러한 사구체 여과율은 사구체 여과율 계산 공식을 어떤 것을 사용하는가에 따라 통계학적으로 유의한 차이가 있었다 (p ≤ 0.002). 다섯 가지의 사구체 여과율 공식 중에서, Modified Cockcroft-Gault 식, MDRD 식과 CKD-EPI 식이 만성신부전 합병증과 유의한 상관관계를 보였다. 특히 Modified Cockcroft-Gault 식의 경우 변동 계수(CV; coefficient of variation)가 가장 작았으며, 이는 이 식이 본 연구의 환자들의 eGFR 값을 가장 재현성 있게 나타낸다는 것을 의미한다. 혈액투석을 시작하게 된 주된 이유는 부종 (38.4%), 요독 증세 (35.0%) 였다. 당뇨 환자는 비당뇨 환자에 비하여 더 나이가 많고, 투석 시작시 높은 사구체 여과율을 보였다. 59.2% 의 환자는 외래를 경유하여 혈액투석을 시작하였고, 40.8% 의 환자는 응급실로 내원하여 혈액투석을 시작하였다. 응급실로 내원하여 투석을 시작한 경우, 고칼륨혈증 및 대사성 산증이 외래 내원하여 시작한 환자군에 비하여 더 심한 소견을 보였다. 현재 한국에서 행해지고 있는 혈액 투석 시작 시점에서의 말기신장질환 환자들의 임상적 특징 및 혈액검사 자료 등의 자료가 향후 투석 시작 시점을 결정하는데 유용한 정보가 되길 기대한다.ABSTRACTS
LIST OF FIGURES
LIST OF TABLES
I. INTRODUCTION
II. METHODS
A. Patient selection
B. Laboratory data
C. Estimated glomerular filtration rate
D. Statistical analysis
III. RESULTS
IV. DISCUSSION
REFERENCES
FIGURES
TABLES
국문요약Maste
Min-yu Chen, piano, April 19, 2017
Get PDFThis is the concert program of the Min-yu Chen, piano performance on Wednesday, April 19, 2017 at 8:00 p.m., at the Concert Hall, 855 Commonwealth Avenue. Works performed were Cinq mélodies populaires grecques by Maurice Ravel, Don Quichotte à Dulcinée by M. Ravel, Fantasiestücke Op. 73 by Robert Schumann, and Violin Sonata No. 2 in A major, Op. 100 by Johannes Brahms. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund
Min-yu Chen, collaborative piano, April 19, 2018
Get PDFThis is the concert program of the Min-yu Chen, collaborative piano performance on Thursday, April 19, 2018 at 8:00 p.m., at the Concert Hall, 855 Commonwealth Avenue. Works performed were Hermit Songs by Samuel Osborne Barber II, Vier Lieder, Op. 27 by Richard Strauss, and Piano Trio in A minor by Maurice Ravel. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund
Producing innovation: Comments on Lee and Yu (2010)
Get PDFThe purpose of the article being reviewed (Lee and Yu, 2010), a survey by questionnaire with 182 valid responses, is to analyze “how different relationship styles of employees in the hi-tech industry influence innovation performance” and indeed its conclusions are that “the relationship style of an organization has a significant positive effect on innovation performance”. We see Lee and Yu (2010) as being similar to another highly cited article by Morgan and Hunt in so far as both articles are about relationships, cooperation and trust
Supplementary_Material – Supplemental material for Institutions, contexts, and ethnic violence in comparative perspective
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