도시캐노피 밑 난류특성매개변수화를 고려한 중규모 모델개발 및 이를 이용한 도시특성 모의

학위논문 (박사)-- 서울대학교 대학원 : 대기과학과, 2014. 2. 윤순창.This study is carried out to simulate the flow and turbulence in urban area for air pollution modeling using a modified urbanized mesoscale model. The Urban Canopy Parameterization (UCP) of Dupont et al. (2004) implemented in MM5v3.7 mesoscale meteorological modeling system (MM5-UCP-Basic) is evaluated against the non-urbanized model (MM5-NoUCP) using measurements taken in urban Phoenix during two field studies. In general, MM5-UCP-Basic improved the predictions of typical meteorological parameters. Nevertheless, significant discrepancies still exist between observations and the predictions of MM5-UCP-Basic, and new parameterizations and land use classes are introduced to improve the model performance. The parameterization of anthropogenic heat flux from buildings and roadways is also included. The land use classes in the improved model (MM5-UCP-MOD) represent roadways and rivers, in addition to five classes of buildings identified in MM5-UCP-Basic. New parameterizations considered the appropriate roughness length, velocity decay during evening transition, and heat and momentum diffusivities for the nocturnal period so that account for different heat and momentum transfer rates under stable atmospheric conditions. Five nested grid domains are used for simulations, with the highest resolution (1km) implemented into the MM5-NoUCP, MM5-UCP-Basic and MM5-UCP-MOD. Improved parameterizations were validated by detailed flow and turbulence measurements which were conducted as the Phoenix SUNRISE field experiment in 2001 (Lee et al., 2003Doran et al., 2003) and TRANSFLEX in 2006 (Fernando et al., 2013). This research was to refine the urban land use classification in MM5-UCP-Basic and modify the turbulence parameterizations to better represent surface fluxes and urban effect such as UHI and LLJs. The features of this modified model, MM5-UCP-MOD, are presented in this research together with its validation and comparisons with MM5-UCP-Basic and original MM5v3.7 (referred to as MM5-noUCP). According to sensitivity tests for parameterization improvement, the parameterization changing the turbulence length scale in TKE is the most significant to develop the high performance of momentum flux in urban simulation. In general, substantial improvements in the prediction of wind speed, temperature (especially during the nighttime) and momentum flux as well as a smaller improvement in the heat flux are noted, so that is pointing to possible further enhancement onto model performance by including the improved physics. By the way, the MM5-UCP-MOD is useful to understand the UHI and urban meteorology so as to simulate and predict the nocturnal air pollution in the city, especially. The temperature field and heat flux including effect of UHI in urban center are better simulated by MM5-UCP-MOD with urban data for Phoenix than by the standard version of MM5 (MM5-NoUCP). Besides, transient events of end of high mountainous area, which enclosed the downtown, are also accomplished to simulate by MM5-UCP-MOD. The transient events are typically developed by coupled effect of topographical condition of Phoenix and thermally driven flow in neighborhood scale. And it seems to be analyzed by drag force approach inside roughness sub-layer. The budgets of turbulent kinetic energy near the boundary from output of MM5-UCP-MOD are able to understand the turbulent energy transform near the top of building canopy. Since three-dimensional observations are not enough to verify the simulation and the use of urban and vegetation canopy morphology database with land use type are too simplified, validation of new parameterization is not enough. Nevertheless, the formation of LLJ owing to UHI and transient events with nocturnal downslope flow in transient time can be explained using MM5-UCP-MOD. And also, this effect produced the nocturnal high ozone concentrations and can be only simulated by MM5-UCP-MOD. Although the limitation of comparison with measurement for ozone and PM10, the analysis of the model outputs emphasized that results from MM5-UCP-MOD and CMAQ are useful to understand and predict the urban meteorology and air pollution.ABSTRACT i TABLE OF CONTENTS v LIST OF FIGURES vii LIST OF TABLES xiii 1. Introduction 1 1.1 Review of previous studies 1 1.1.1 Urbanized meso-scale meteorological model 1 1.1.2 Urban heat island (UHI) phenomena 6 1.2 Motivation and Objectives of research 8 2. Implementation of new Urban Canopy Parameterization 12 2.1 Introduction 12 2.2 Implementation of Urban Canopy Parameterization (UCP) in MM5 for Phoenix in MM5 18 3. Application and modification of turbulence parameterization in MM5-UCP-Basic 28 3.1 Setup and simulation condition in MM5 28 3.2 Comparison of simulations with surface observations 30 3.3 Modification of turbulence parameterizations in MM5-UCP -Basic 38 3.3.1 Brief description of turbulence parameterization in DA-SM2-U 38 3.3.2 Issues of original MM5-UCP-Basic and modifications 45 4. Validation and sensitivity of MM5-UCP-MOD 53 4.1 Comparison of simulations with surface observations 53 4.1.1 Field experiments 53 4.1.2 Numerical simulations 58 4.2 Sensitivity to each improvement 59 4.3 Simulation results of modified version, MM5-UCP-MOD 63 5. Application of MM5-UCP-MOD to Urban Effects simulations 72 5.1 Impacts of urban heat island effect 72 5.2 Urban effect on transient event 86 5.3 Effect on air pollution distribution 96 5.3.1 Air pollution modeling 96 5.3.2 Results of air pollution modeling 97 6. Summary and conclusion 105 REFERENCES 109 국문 초록 119Docto

Optimierungsrahmen für die Verbesserung der Energieflexibilität in Wohngebäuden

Energy flexibility is balancing the supply and demand of a building according to climate conditions, user preferences, and grid constraints. Energy flexibility in households is a practical approach to achieving sustainability in the building sector. However, the diversity in flexibility potential of energy systems and climatic variability complicate the selection of envelope parameters and building energy systems (BESs). This study aimed to design a framework to improve the energy flexibility of the building. For this purpose, a single-family house and diversified BESs were simulated in a TRNSYS-Python co-simulation platform. Initially, the bi-objective optimization identified flexible building envelopes in twenty-four locations. Then, the multi-criteria assessment of BESs was conducted using life-cycle energy flexibility indicators. Lastly, the energy flexibility potential of the BES was evaluated by employing steady-state optimization and model predictive control (MPC). The findings of this work set a benchmark for flexible household envelopes. The systematic approach for selecting BES could guide the energy system design, providing insight into energy flexibility. Further, this investigation has established that the dataset of building thermal load, boundary conditions, and control disturbances can be used to develop an MPC-based dynamic control. That controller could be employed on different BESs to achieve energy flexibility.Energieflexibilität ist der Ausgleich von Versorgung und Bedarf eines Gebäudes je nach Klima, Nutzerpräferenzen und Netzbeschränkungen. Energieflexibilität ist damit ein praktischer Ansatz für Nachhaltigkeit in Gebäuden. Die Vielfalt des Flexibilitätspotenzials von Energiesystemen und die klimatischen Unterschiede erschweren jedoch die Auswahl von Hüllparametern und Gebäudeenergiesystemen (BESs). Diese Studie zielte darauf ab, einen Rahmen zur Verbesserung der energetischen Flexibilität von Gebäuden zu entwickeln. Hierzu wurden ein Einfamilienhaus und verschiedene BES in einer TRNSYS-Python Co-Simulationsplattform simuliert. Zunächst wurden über eine bi-objektive Optimierung flexible Gebäudehüllen an vierundzwanzig Standorten ermittelt. Danach erfolgte eine multikriterielle Bewertung der BES anhand von Energieflexibilitätsindikatoren über den gesamten Lebenszyklus. Schließlich wurde das Energieflexibilitätspotenzial der BES durch den Einsatz statischer Optimierung und modellprädiktiver Regelung (MPC) bewertet. Die Ergebnisse dieser Arbeit setzen einen Maßstab für flexible Gebäudehüllen. Der systematische Ansatz zur Auswahl von BES könnte als Leitfaden für die Auslegung zukünftiger Systeme dienen. Darüber hinaus hat die Untersuchung ergeben, dass Daten zu thermischer Belastung des Gebäudes, Randbedingungen und Regelungsstörungen zur Entwicklung eines MPC verwendet werden können. Dieser Regler könnte bei verschiedenen BES eingesetzt werden, um Energieflexibilität zu erreichen

Metabolic control of DNA methylation in naive pluripotent cells.

Naive epiblast and embryonic stem cells (ESCs) give rise to all cells of adults. Such developmental plasticity is associated with genome hypomethylation. Here, we show that LIF-Stat3 signaling induces genomic hypomethylation via metabolic reconfiguration. Stat3-/- ESCs show decreased α-ketoglutarate production from glutamine, leading to increased Dnmt3a and Dnmt3b expression and DNA methylation. Notably, genome methylation is dynamically controlled through modulation of α-ketoglutarate availability or Stat3 activation in mitochondria. Alpha-ketoglutarate links metabolism to the epigenome by reducing the expression of Otx2 and its targets Dnmt3a and Dnmt3b. Genetic inactivation of Otx2 or Dnmt3a and Dnmt3b results in genomic hypomethylation even in the absence of active LIF-Stat3. Stat3-/- ESCs show increased methylation at imprinting control regions and altered expression of cognate transcripts. Single-cell analyses of Stat3-/- embryos confirmed the dysregulated expression of Otx2, Dnmt3a and Dnmt3b as well as imprinted genes. Several cancers display Stat3 overactivation and abnormal DNA methylation; therefore, the molecular module that we describe might be exploited under pathological conditions

Metabolic control of DNA methylation in naive pluripotent cells.

Naive epiblast and embryonic stem cells (ESCs) give rise to all cells of adults. Such developmental plasticity is associated with genome hypomethylation. Here, we show that LIF-Stat3 signaling induces genomic hypomethylation via metabolic reconfiguration. Stat3-/- ESCs show decreased α-ketoglutarate production from glutamine, leading to increased Dnmt3a and Dnmt3b expression and DNA methylation. Notably, genome methylation is dynamically controlled through modulation of α-ketoglutarate availability or Stat3 activation in mitochondria. Alpha-ketoglutarate links metabolism to the epigenome by reducing the expression of Otx2 and its targets Dnmt3a and Dnmt3b. Genetic inactivation of Otx2 or Dnmt3a and Dnmt3b results in genomic hypomethylation even in the absence of active LIF-Stat3. Stat3-/- ESCs show increased methylation at imprinting control regions and altered expression of cognate transcripts. Single-cell analyses of Stat3-/- embryos confirmed the dysregulated expression of Otx2, Dnmt3a and Dnmt3b as well as imprinted genes. Several cancers display Stat3 overactivation and abnormal DNA methylation; therefore, the molecular module that we describe might be exploited under pathological conditions

A comparative analysis of small advanced naval vehicles and displacement-hull naval ship design

Thesis (Ocean. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1989.Includes bibliographical references (leaves 139-142).by Markos Nicolaos Vassilikos.Ocean.E

Topics in Automotive Rollover Prevention: Robust and Adaptive Switching Strategies for Estimation and Control

The main focus in this thesis is the analysis of alternative approaches for estimation and control of automotive vehicles based on sound theoretical principles. Of particular importance is the problem rollover prevention, which is an important problem plaguing vehicles with a high center of gravity (CG). Vehicle rollover is, statistically, the most dangerous accident type, and it is difficult to prevent it due to the time varying nature of the problem. Therefore, a major objective of the thesis is to develop the necessary theoretical and practical tools for the estimation and control of rollover based on robust and adaptive techniques that are stable with respect to parameter variations. Given this background, we first consider an implementation of the multiple model switching and tuning (MMST) algorithm for estimating the unknown parameters of automotive vehicles relevant to the roll and the lateral dynamics including the position of CG. This results in high performance estimation of the CG as well as other time varying parameters, which can be used in tuning of the active safety controllers in real time. We then look into automotive rollover prevention control based on a robust stable control design methodology. As part of this we introduce a dynamic version of the load transfer ratio (LTR) as a rollover detection criterion and then design robust controllers that take into account uncertainty in the CG position. As the next step we refine the controllers by integrating them with the multiple model switched CG position estimation algorithm. This results in adaptive controllers with higher performance than the robust counterparts. In the second half of the thesis we analyze extensions of certain theoretical results with important implications for switched systems. First we obtain a non-Lyapunov stability result for a certain class of linear discrete time switched systems. Based on this result, we suggest switched controller synthesis procedures for two roll dynamics enhancement control applications. One control design approach is related to modifying the dynamical response characteristics of the automotive vehicle while guaranteeing the switching stability under parametric variations. The other control synthesis method aims to obtain transient free reference tracking of vehicle roll dynamics subject to parametric switching. In a later discussion, we consider a particular decentralized control design procedure based on vector Lyapunov functions for simultaneous, and structurally robust model reference tracking of both the lateral and the roll dynamics of automotive vehicles. We show that this controller design approach guarantees the closed loop stability subject to certain types of structural uncertainty. Finally, assuming a purely theoretical pitch, and motivated by the problems considered during the course of the thesis, we give new stability results on common Lyapunov solution (CLS) existence for two classes of switching linear systems; one is concerned with switching pair of systems in companion form and with interval uncertainty, and the other is concerned with switching pair of companion matrices with general inertia. For both problems we give easily verifiable spectral conditions that are sufficient for the CLS existence. For proving the second result we also obtain a certain generalization of the classical Kalman-Yacubovic-Popov lemma for matrices with general inertia

A study of safety and production problems and safety strategies associated with industrial robot systems

Imperial Users onl

Investigation of the role of the extracellular β-agarase, produced by the bacterial epiphyte Pseudoalteromonas sp. LS2i, in the virulence response towards the agarophyte Gracilaria gracilis

Includes abstractIncludes bibliographical referencesGracilaria gracilis that grows naturally at Saldanha Bay, South Africa is economically important as a source of agar. The Gracilaria yields from natural beds at Saldanha Bay are however unreliable, and consequently the South African Gracilaria industry has experienced a number of setbacks over the years. The only way a consistent supply can be assured is by mariculture to supplement the natural harvests. In 1993 the Seaweed Research Institute (SRU) found that mariculture of G. gracilis in Saldanha Bay is feasible but that there is potential to improve yields by technical research and development (Anderson et al.1996a). Jaffray and Coyne (1996) developed a pathogenicity assay that demonstrated that agarolytic bacteria isolated from Saldanha Bay Gracilaria induced disease symptoms such as thallus bleaching, while non-agarolytic isolates did not. It is thought that unfavorable environmental conditions such as elevated water temperature and nutrient depletion, which occur during the summer months in the surface layers of the water column in Saldanha Bay, induce the onset of agarase production or result in changes in the bacterial community structure in which agarase-producers become more dominant. By using the pathogenicity assay, Jaffray and Coyne (1996) identified the highly agarolytic Gracilaria gracilis pathogen, Pseudoalteromonas sp. LS2i. The aim of this study was to characterize the bacterial pathogen, Pseudoalteromonas sp. LS2i to further our understanding of virulence regulation and specifically, the role of the agarase enzymes in the process of seaweed-pathogen interaction. Two agarolytic clones, pEB1 and pJB1, were obtained after constructing and screening a Pseudoalteromonas sp. LS2i genomic library in Esherichia coli. Restriction enzyme mapping suggested that both clones contain the same agarase gene. Southern hybridization studies confirmed the origin of the cloned DNA and sequencing studies revealed the 1062 bp ORF, putative promoter region, putative ribosome binding site and putative transcriptional start point of the cloned agarase gene. The ORF showed sequence identity to several other β-agarases and was identified as a member of the GH-16 family of glycoside hydrolases. The agarase was purified from the E. coli JM109 (pEB3) transformant. The molecular weight was estimated to be 39 kDa by SDS-PAGE. Zymogram analysis confirmed that the purified protein is agarolytic and TLC analysis revealed that the predominant end-products of agar hydrolysis are neoagarohexaose and neoagarobiose, which indicates the same mode of action as that observed for the agarase produced extracellularly by Pseudoalteromonas sp. LS2i

The Effect of Culture and Religion on Enforcement of International Arbitration Awards in Iran

My goal in this dissertation is to explore some of the rules of Sharia with regard to the arbitration and reduce this level of non-recognition of the Islamic legal system by the West. Also, I am going to analyze the Iranian culture and its effect on enforcement of international arbitration awards and suggest some solutions to reduce the cultural obstacles m the enforcement of foreign arbitration awards