Mechanisms for the Decadal Change of the MJO Teleconnection over the Northern Hemisphere in Boreal Winter

Department of Urban and Environmental Engineering (Environmental Science and Engineering)This thesis suggests dynamical mechanisms for the decadal change of the MJO teleconnection pattern over the Northern Hemisphere during boreal winter by investigating the influence of the decadal change of background states in the mid-latitude and tropical forcing on MJO teleconnection pattern and interpreting this relationship. Thus, it is important to understand how these changes influence on MJO teleconnection pattern to represent the MJO teleconnection pattern caused by changes of background states and MJO activities over the tropics. In boreal winter, OLR variance with intraseasonal variability variance is strengthened over the Maritime Continent and weakened over the southern Indian Ocean and the western Pacific. This is consistent with the results of the MJO amplitude at each MJO phase based on OMI. These changes of MJO activity are associated with the La Nina-like change of background states in tropics. There is wet and warm anomaly over the Maritime Continent and the western Pacific, and ascending motion over the Maritime Continent, whereas dry, cold and descending anomaly over the central and the eastern Pacific. The location of MJO teleconnection patterns can be determined by seasonal mean upper-level zonal wind acted as a waveguide. The obvious change of the jet stream is found, especially over the eastern Pacific. Over this region, stationary Rossby wavenumber is expanded east and northward in the recent period than that in the past period. This change modifies the location and intensity of the teleconnection patterns based on the analysis of zonal wavenumber. Based on the model experiments, the decadal change in the background states, especially zonal wind at the upper level, leads to strengthening the intensity of the MJO teleconnection pattern over the jet exit region but does not modify the pattern itself. On the other hand, the tropical heating modifies the teleconnection patterns over the North Pacific and North America, and these changes are similar to the observed difference maps between the two periods. Thus, the results indicate that the decadal change of the MJO teleconnection pattern is caused by the change of tropical diabatic heating rather than the change of zonal wind in the mid-latitude as background states. These changes are associated with the background states are changed into La Nina-like pattern in the recent period. This leads to moisture and SST increase over the warm pool region. In addition, the ascending motion of the vertical circulation in the background states strengthens over the eastern region of Maritime Continent, and then the convective anomaly becomes stronger over this region in the recent period than in the past period. It is thought that these background changes including the intensification of the vertical circulation lead to the enhancement of the MJO teleconnection pattern and its teleconnectivity over the upstream regions. Furthermore, there is close relationship of the MJO teleconnection patterns between P1 and El Nino years or P2 and La Nina years.clos

The WTO-Consistency Issues of Countervailing Currency Undervaluation

The US Department of Commerce (USDOC) adopted a new rule to impose a countervailing duty (CVD) on imports from countries undervaluing their currencies, arguing that an artificially weak exchange rate amounts to an export subsidy. This ruling, however, raises a variety of systemic and legal problems of whether it is possible to regulate exchange rates under the multilateral trading system. In fact, it raises a fundamental issue about coherent governance on international economic systems to bridge between financial and trade institutions. In addition, it questions whether it is possible to consider currency undervaluation as a countervailable subsidy under the Agreement on Subsidies and Countervailing Measures (ASCM). This paper highlights the structural limitations of regulatory evolution in the WTO and IMF. In addition, this analysis shows that the manner the CVD was applied causes many legal problems in terms of WTO consistency. Considering huge potential implications of currency-based CVDs, it is imperative for the WTO Members to agree on proper guidelines that discipline overly excessive use of trade remedy measures

A Three-dimensional Deviation Analysis by the Coordinate Registration of Randomly Positioned Objects

Department of Mechanical EngineeringIt is very important to accurately inspect machining errors, assembly tolerances of product in manufacturing industry. Recently, a three-dimensional measurement system is widely used for industrial inspection. Typical three-dimensional measurement methods include a coordinate measuring machine (CMM), a line laser scanning method, and a structured light system comprising a camera and light source for generating a pattern. In general, the inspection system applying the three-dimensional measurement method require the physical calibration processing using special device to place object at home position with desired pose. However, such a process requires a considerable time for measurement, and it inhibits the flexibility of measurement spatially. Therefore, to solve this problem, this thesis proposed a methodology to measurement of randomly positioned objects by coordinate recognition. It is assumed that the position and pose of object is varied at every measurement. Coordinate of CAD model must be brought to the coordinate of measured data to calculate deviation of object. Transformation parameters of two coordinates are derived by following procedure. reference plane selection is preceded before measurement as preprocessing. The first step is rough registration based on principal component analysis and iterative closest point algorithm. The second step is main methodology of this thesis, which is coordinate adjustment to calibrate transformation parameters. Coordinate adjustment is composed of two stages, which are reference plane matching for calibrating rotation parameters and edge matching for translation parameters. Then, deviation is calculated by comparison to the CAD model.ope

Advanced Mission Design: Interplanetary Super Highway Trajectory Method

Near-future space missions demand the delivery of massive payloads to deep space destinations. Given foreseeable propulsion technology, this is feasible only if we can design trajectories that require the smallest possible propulsive energy input. This research aims to design interplanetary space missions by using new low-energy trajectory methods that take advantage of natural dynamics in the solar system. This energy efficient trajectory technology, called the Interplanetary Super Highway (IPSH), allows long duration space missions with minimum fuel requirements. To develop the IPSH trajectory design method, invariant manifolds of the three-body problem are used. The invariant manifolds, which are tube-like structures that issue from the periodic orbits around the L1 and L2 Lagrangian points, can be patched together to achieve voyages of immense distances while the spacecraft expends little or no energy. This patched three-body method of trajectory design is fairly well developed for impulsive propulsion. My research is dedicated to advance its capabilities by extending it to continuous, low-thrust, high specific impulse propulsion methods. The IPSH trajectory design method would be useful in designing many types of interplanetary missions. As one of its applications, my research is focused on Near-Earth Asteroids (NEAs) rendezvous mission design for exploration, mitigation, and mining. Asteroids have many valuable resources such as minerals and volatiles, which can be brought back to Earth or used in space for propulsion systems or space habitats and stations. Transportation to and from asteroids will require relatively massive vehicles capable of sustaining crew for long durations while economizing on propellant mass. Thus, in the design of advanced NEA rendezvous missions, developing new technology for low cost trajectories will play a key role. In a second application study, the solar sail mission for Mars exploration is considered. By using solar radiation pressure, solar sails provide propulsive power. This thrust affects the three-body system dynamics such that the Sun-Mars L1 and L2 Lagrangian points are shifted toward the Sun and the geometry of the invariant manifolds around L1 and L2 points is changed. By taking advantage of these features, a low-thrust trajectory for Mars exploration is developed

Effect of delayed sample draw after blood collection for haemoglobin test in South Korea

Between April and May 2022, 10 healthy adult non-patients were recruited from Pusan National University Hospital. Venous blood drawn into a syringe was transferred into test tubes with a zero-to-45-minute delay. The transfer was done sequentially in two positions with the syringe and the needle adaptor end (1) heading downwards and (2) heading upwards. Haemoglobin levels gradually increased over time in position 1 transfer while they gradually decreased in position 2. Therefore, blood must be transferred quickly from a syringe to a tube for reliable test results. What this study adds: Our findings confirm that delays between blood collection and transfer can affect haemoglobin levels

CMASS galaxy sample and the ontological status of the cosmological principle

The cosmological principle (CP), assuming spatially homogeneous and isotropic background geometry in the cosmological scale, is a fundamental assumption in modern cosmology. Recent observations of the galaxy redshift survey provide relevant data to confront the principle with observation. We present a homogeneity test for the matter distribution using the BOSS DR12 CMASS galaxy sample and clarify the ontological status of the CP. As a homogeneity criterion, we compare the observed data with similarly constructed random distributions using the number count in the truncated cones method. Comparisons are also made with three theoretical results using the same method: (i) the dark matter halo mock catalogs from the N-body simulation, (ii) the log-normal distributions derived from the theoretical matter power spectrum, and (iii) direct estimation from the theoretical power spectrum. We show that the observed distribution is statistically impossible as a random distribution up to 300 Mpc/h in radius, which is around the largest statistically available scale. However, comparisons with the three theoretical results show that the observed distribution is consistent with these theoretically derived results based on the CP. We show that the observed galaxy distribution (light) and the simulated dark matter distribution (matter) are quite inhomogeneous even on a large scale. Here, we clarify that there is no inconsistency surrounding the ontological status of the CP in cosmology. In practice, the CP is applied to the metric and the metric fluctuation is extremely small in all cosmological scales. This allows the CP to be valid as the averaged background in metric. The matter fluctuation, however, is decoupled from the small nature of metric fluctuation in the subhorizon scale. What is directly related to the matter in Einstein's gravity is the curvature, a quadratic derivative of the metric.Comment: 12 pages, 13 figures, 1 tabl

An efficient strategy for cell-based antibody library selection using an integrated vector system

BACKGROUND: Cell panning of phage-displayed antibody library is a powerful tool for the development of therapeutic and imaging agents since disease-related cell surface proteins in native complex conformation can be directly targeted. Here, we employed a strategy taking advantage of an integrated vector system which allows rapid conversion of scFv-displaying phage into scFv-Fc format for efficient cell-based scFv library selection on a tetraspanin protein, CD9. RESULTS: A mouse scFv library constructed by using a phagemid vector, pDR-D1 was subjected to cell panning against stable CD9 transfectant, and the scFv repertoire from the enriched phage pool was directly transferred to a mammalian cassette vector, pDR-OriP-Fc1. The resulting constructs enabled transient expression of enough amounts of scFv-Fcs in HEK293E cells, and flow cytometric screening of binders for CD9 transfectant could be performed simply by using the culture supernatants. All three clones selected from the screening showed correct CD9-specificity. They could immunoprecipitate CD9 molecules out of the transfectant cell lysate and correctly stain endogenous CD9 expression on cancer cell membrane. Furthermore, competition assay with a known anti-CD9 monoclonal antibody (mAb) suggested that the binding epitopes of some of them overlap with that of the mAb which resides within the large extracellular loop of CD9. CONCLUSIONS: This study demonstrates that scFv-Fc from mammalian transient expression can be chosen as a reliable format for rapid screening and validation in cell-based scFv library selection, and the strategy described here will be applicable to efficient discovery of antibodies to diverse cell-surface targets

Alternative to Null Hypothesis Significance Testing (NHST): Understanding the Bayesian Approach

Null Hypothesis Significance Testing is the most widely used method of analysis in social science. However, there are inherent limitations of NHST. We discuss the problems of using NHST and suggest alternative ways to solve the problems, focusing on Bayesian statistics. To supplement the limitation of NHST it has been argued that providing information regarding the effect size and confidence interval are useful. Furthermore, Bayesian statistics, which is an independent stream of study, has gained attention. We introduce the basic concept of Bayesian statistics and the application of the method in organizational research.This study was supported by the Institude of Management Research at Seoul National University

Patch-Mix Contrastive Learning with Audio Spectrogram Transformer on Respiratory Sound Classification

Respiratory sound contains crucial information for the early diagnosis of fatal lung diseases. Since the COVID-19 pandemic, there has been a growing interest in contact-free medical care based on electronic stethoscopes. To this end, cutting-edge deep learning models have been developed to diagnose lung diseases; however, it is still challenging due to the scarcity of medical data. In this study, we demonstrate that the pretrained model on large-scale visual and audio datasets can be generalized to the respiratory sound classification task. In addition, we introduce a straightforward Patch-Mix augmentation, which randomly mixes patches between different samples, with Audio Spectrogram Transformer (AST). We further propose a novel and effective Patch-Mix Contrastive Learning to distinguish the mixed representations in the latent space. Our method achieves state-of-the-art performance on the ICBHI dataset, outperforming the prior leading score by an improvement of 4.08%.Comment: INTERSPEECH 2023, Code URL: https://github.com/raymin0223/patch-mix_contrastive_learnin