경구최소모델을 기반으로 한 포도당 대사에서의 최적화와 제어

학위논문 (석사)-- 서울대학교 대학원 : 의학과 의공학전공, 2016. 8. 김성완.In the mathematical models to describe physiological phenomena, optimization problem and control tactics are important. Because optimal parameters to represent status of subjects should be estimated and biological variables beyond the normal range should be recovered by using of the pertinent control or interventions. For this objective, the model is required to be validated based on clinical data and the optimal algorithm for each subject is able to be designed. The oral minimal model is the mathematical system to understand glycemic control in vivo, which can be helpful to evaluate the beta-cell function and insulin sensitivity. In this study, 10 healthy subjects with normal glucose tolerance and 14 patients with type 2 diabetes mellitus participated. In the results, firstly, blood glucose concentration level, C-peptide level, and Insulin response can be predicted by using of the oral minimal model. Secondly, insulin sensitivity and disposition indices are lower in type 2 diabetes group than normal group. Thirdly, the oral minimal model indices are well correlated with pre-existing clinical indices. Therefore the oral minimal model could be applied to the Korean. Furthermore, a proportional-integral-derivative (PID) controller and optimal control using dynamic programming can be used to establish algorithms to control blood glucose level in type 2 diabetes mellitus. PID controller showed capability to lower glucose level efficiently and the level of the glucose was continuously lowered without fluctuation. An optimal control scheme with two simplified additional insulin loading profiles also could lower blood glucose level efficiently, and the barrier term in the cost function could prevent too low blood glucose level. Among 14 T2DM patients, immediate injections of two insulin loadings were recommended in most cases for effective control of the glucose level. Based on this model and tactics, it is expected that latent interactions in glucose metabolism are clarified, and the models and efficient control algorithms for the artificial pancreas could be developed.1. Introduction 1 1.1.The mathematical modeling in glucose metabolism 1 1.2.The necessity of the simulation study 2 2. Optimization and control problems in the oral minimal model 4 2.1.Concepts of the oral minimal model 4 2.2.The mathematical systems in the oral minimal model 7 2.3.Optimization problems in the oral minimal model 11 2.4.Control problems in the oral minimal model 13 3. Method 15 3.1.Subjects and ethical statement 15 3.2.Study procedure in clinical experiments 15 3.3.Parameter estimation 16 3.4.Calculation for indices 17 3.5.Statistical analysis 21 3.6.Simulation of control procedures 21 4. Results 24 4.1.Clinical characteristics of the subjects 24 4.2.Simulation of plasma glucose level and C-peptide secretion 26 4.3.Insulin sensitivity, beta-cell responsivity indices and hepatic insulin extraction ratios 29 4.4.Disposition indices between NGT and T2DM groups 31 4.5.Correlation between other indices of insulin secretion or insulin action and the oral minimal model indices 35 4.6.Correlation between glucose levels and the oral minimal model indices 37 4.7.Simulation of glucose control tactics via additional insulin 39 5. Discussion 46 6. Conclusion 52 References 53 Abstract in Korean 60Maste

Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission.

We report on the fabrication of novel InGaN nanowires (NWs) with improved crystalline quality and high radiative efficiency for applications as nanoscale visible light emitters. Pristine InGaN NWs grown under a uniform In/Ga molar flow ratio (UIF) exhibited multi-peak white-like emission and a high density of dislocation-like defects. A phase separation and broad emission with non-uniform luminescent clusters were also observed for a single UIF NW investigated by spatially resolved cathodoluminescence. Hence, we proposed a simple approach based on engineering the axial In content by increasing the In/Ga molar flow ratio at the end of NW growth. This new approach yielded samples with a high luminescence intensity, a narrow emission spectrum, and enhanced crystalline quality. Using time-resolved photoluminescence spectroscopy, the UIF NWs exhibited a long radiative recombination time (τr) and low internal quantum efficiency (IQE) due to strong exciton localization and carrier trapping in defect states. In contrast, NWs with engineered In content demonstrated three times higher IQE and a much shorter τr due to mitigated In fluctuation and improved crystal quality

Design and Implementation of a Full-Duplex Pipelined MAC Protocol for Multihop Wireless Networks

In multihop wireless networks, data packets are forwarded from a source node to a destination node through intermediate relay nodes. With half-duplex relay nodes, the end-to-end delay performance of a multihop network degrades as the number of hops increases, because the relay nodes cannot receive and transmit at the same time. Full-duplex relay nodes can reduce their per-hop delay by starting to forward a packet before the whole packet is received. In this paper, we propose a pipelined medium access control (PiMAC) protocol, which enables the relay nodes on a multihop path to simultaneously transmit and receive packets for full-duplex forwarding. For pipelined transmission over a multihop path, it is important to suppress both the self-interference of each relay node with the full-duplex capability and the intra-flow interference from the next relay nodes on the same path. In the PiMAC protocol, each relay node can suppress both the self- and intra-flow interference for full-duplex relaying on the multihop path by estimating the channel coefficients and delays of the interference during a multihop channel acquisition phase. To evaluate the performance of the PiMAC protocol, we carried out extensive simulations and software-defined radio-based experiments

The Relationship between Aldosterone to Renin Ratio and RI Value of the Uterine Artery in the Preeclamptic Patient vs. Normal Pregnancy

aldosterone are increased during normal pregnancy. However, these values in preeclampsia are decreased to nearly that of a nonpregnant subject, and vascular sensitivity to angiotensin II is increased. In preeclampsia, aldosterone is decreased less than rennin. Therefore current studies were undertaken to determine the relationship between aldosterone to renin ratio (ARR) and uterine artery perfusion via RI value. Materials and Methods: In this study, the relationship between plasma aldosterone and renin concentration was determined in 27 preeclamptic women and 50 normal pregnant women, whose gestational weeks were matched. The aldosterone to renin ratio was calculated and compared between the two groups. Doppler velocimetry of the uterine artery, which was used to calculate resistance index (RI), was performed on all subjects. The relationship between ARR and RI value was reviewed

Implementing a Real Name Financial Transaction System to Increase Transparency and Reduce Corruption

A real-name financial transaction system (RNFTS) requires that the real name of an individual or a legal entity be used in financial transactions, subject to verification by some form of identification. By enhancing the integrity and transparency of financial transactions, RNFTS aims to address the development challenge of reducing corruption and promoting fair taxation. Introducing RNFTS entails basically two types of delivery challenges: technical and political economy. The technical challenge has to do with setting up data infrastructure and dealing with verification and transition problems while safeguarding financial privacy. The political economy challenge has to do with overcoming the resistance of those who wanted to keep financial transactions secret. Since the early 1980s, successive governments in Korea acknowledged the imperative of financial transparency and integrity, but their commitment to implement the requisite reform fluctuated depending on political and economic conditions. In fact, although technical challenges associated with RNFTS had been largely addressed by the mid-1980s, political economy issues prevented its implementation until 1993. Introducing RNFTS is generally regarded as a case of concentrated costs and dispersed benefits, where reform-minded citizens must play entrepreneurial politics to mobilize the support of the general public to overcome the resistance of the powerful vested interest. However, under certain conditions, it may more resemble a case of concentrated costs and concentrated benefits, where a few reformers derive a disproportionate share of benefits against their political rivals. In Korea’s case, the payoff structure associated with RNFTS seems to have gone through this shift from the 1980s to 1993

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