Quark number Susceptibility and Phase Transition in hQCD Models

We study the quark number susceptibility, an indicator of QCD phase transition, in the hard wall and soft wall models of hQCD. We find that the susceptibilities in both models are the same, jumping up at the deconfinement phase transition temperature. We also find that the diffusion constant in the soft wall model is enhanced compared to the one in the hard wall model.Comment: 14 pages, 2 figure

Investigation of material, chemical, and electrochemical properties of Li10SiP2S12-xOx and Li10[SnySi1-y]P2S12-xOx solid electrolytes

With the increasing demand and desire for stronger power and longer life of lithium ion batteries, the lithium ion battery (LIB) system is needed to be developed into next level while it is overcoming the traditional safety issues originated from the use of organic liquid electrolyte. By the physically strong and none volatile feature of solid, one of the simplest and best way to replace the organic liquid electrolyte apply the solid-state electrolyte and establish the all solid-state battery (ASSB). Furthermore, the ASSB system can give an advantage to use Alkali metals to LIB system as electrode that has much huge potential capacity compared to the commercialized current cathode and anode LIB materials. This research studies two sulfide-based solid-state electrolytes, Li10SiP2S12-xOx (LSiPSO) and Li10[SnySi1-y]P2S12-xOx (LSnSiPSO), a crystalline material based on the Li10GeP2S12 (LGPS) high Li+ ion conductive material. The initial Li+ ion conductivity increase and optimization was observed with the substitution of oxygen into crystal structure of Li10SiPS12, and it is a new phenomenon not confirmed with the LGPS and its oxygen substitution. Further spectroscopy and crystallography analysis reveals that there is a formation of oxy-sulfide phase. The phase purification effect by the added oxygen is also observed that it is consuming impurity phases and coverts them into the high Li+ ion conductive LGPS like phase. However, a high oxygen substitution gives a trade-off between the phase purity and Li+ ion conductivity of material. The high addition of oxygen causes a phase degradation into oxide crystalline phase. The investigation of structure and properties of LSnSiPSO shows the same phase purification by the oxygen substitution but it is much enhanced with the additional substitution of tin. The improved phase purification effect is expected that it was possible to form a much close crystal structure to the parent LGPS by the distribution of large ion sized tin to the LSiPSO structure. Finally, ASSB assembled with the LSiPSO and LSnSiPSO samples as SE with Li metal electrode. The impedance and cyclic voltammetry (CV) analysis of the LSiPSO and LSnSiPSO exhibit a formation of solid electrolyte interface (SEI) layer which leads a consumption/deformation of the solid-state electrolyte and Li metal. CV analysis reveals chemical reactions such as redox reaction of Si, Sn, S, and P on the interface between the SE and Li metal. The cycled batteries failed with a constant current density of 0.3 mA/cm2. However, the LSnSiPSO samples showed more stable cycling behavior than the LSiPSO sample

Essays on auctions and mechanism design

There are two directions in studying trading mechanisms: studying outcomes that existing mechanisms generate and designing mechanisms that satisfy desired outcomes. In this dissertation, I explore trading mechanisms in these directions. In the first chapter, I study the first price auction with independent private valuations, wherein each bidder faces ambiguity about the probability distribution from which the other bidders’ valuations for the item are drawn. Each bidder is ambiguity averse and this ambiguity is represented by a set of priors. In this informational setting, I identify a maxmin Bayesian Nash equilibrium of the auction and show that the bidders’ bids and the seller’s expected revenue increase with the level of the bidders’ ambiguity if the bidders’ valuation distribution satisfies the monotone inverse hazard rate condition. I also show that the seller’s expected revenue from the first price auction is greater than that from the second price auction. In the second chapter, I examine a trading mechanism in which traders’ valuations for an item are interdependent. Trade can occur between multiple buyers and multiple sellers. The transfer rules of the trading mechanism are motivated by the second price auction. The mechanism satisfies ex-post efficiency, ex-post incentive compatibility, and ex-post individual rationality. An example in which the mechanism generates a budget deficit is provided. The result of this chapter leads to my work on an impossibility result in the next chapter. In the third chapter, I study trading mechanisms in which traders’ valuations for an indivisible item are interdependent. Trade can occur between one buyer and one seller. Under the assumption that each trader’s information has a greater marginal effect on her own valuation than on the other trader’s valuation, no trading mechanisms satisfying ex-post efficiency, ex-post incentive compatibility, ex-post individual rationality, and no ex-post budget deficit exist

An investigation of the relationship between cultural competence and expatriate job performance

This dissertation investigates whether cultural competence, defined as a person’s ability to interact effectively with others from a different cultural background or in a cross-cultural setting, predicts expatriate adjustment and job performance more effectively than other individual-level predictors such as personality and local language proficiency. Rather than simply focusing on the predictive validity of cultural competence, this study also explores a process model that could explain the link between cultural competence and expatriate job performance by proposing a mediating variable of cross-cultural adjustment. Lastly, in a more integrated way, this study examines how the relationship between expatriate adjustment and job performance may be better understood by two potential moderating variables: conscientiousness and expatriate assignment nature. For testing the proposed hypotheses, expatriates in a Fortune 500 company were invited to participate in a web-based survey. Responses about their international assignment experience were obtained from 338 expatriates located in 43 countries, and their supervisors. A set of multiple regression analyses were conducted and three major findings emerged. First, the analyses confirmed the important role of some individual difference such as conscientiousness and local language proficiency in expatriate assignment effectiveness, consistent with the literature. Second, the results showed the unique roles of some cultural competence dimensions in predicting expatriate adjustment and job performance, beyond the effects of other important individual-level variables. Lastly, the results also demonstrated a process model of the effect of motivational cultural competence on expatriate job performance: motivational cultural competence works through work adjustment to influence expatriate job performance. Taken together, these findings provide more comprehensive knowledge about whether and how certain individual differences are related more effectively to expatriate assignment effectiveness. In practical terms, this research has implications regarding expatriate selection and development, in order to improve the chances of success in international assignments

Implicit Inverse Force Identification Method of Acoustic Liquid-structure Interaction Finite Element Model

The two-field vibroacoustic finite-element (FE) model requires a relatively large number of degrees of freedom compared to the monophysics model, and the conventional force identification method for structural vibration can be adjusted for multiphysics problems. In this study, an effective inverse force identification method for an FE vibroacoustic interaction model of an interior fluid-structure system was proposed. The method consists of: (1) implicit inverse force identification based on the Newmark-$\beta$ time integration algorithm for stability and efficiency, (2) second-order ordinary differential formulation by avoiding the state-space form causing large degrees of freedom, (3) projection-based multiphysics reduced-order modeling for further reduction of degrees of freedom, and (4) Tikhonov regularization to alleviate the measurement noise. The proposed method can accurately identify the unmeasured applied forces on the in situ application and concurrently reconstruct the response fields. The accuracy, stability, and computational efficiency of the proposed method were evaluated using numerical models and an experimental testbed. A comparative study with the augmented Kalman filter method was performed to evaluate its relative performance.Comment: 31 Pages, 20 Figures, 5 Table

Improving I/O Resource Sharing of Linux Cgroup for NVMe SSDs on Multi-core Systems

Abstract In container-based virtualization where multiple isolated containers share I/O resources on top of a single operating system, efficient and proportional I/O resource sharing is an important system requirement. Motivated by a lack of adequate support for I/O resource sharing in Linux Cgroup for high-performance NVMe SSDs, we developed a new weight-based dynamic throttling technique which can provide proportional I/O sharing for container-based virtualization solutions running on NUMA multi-core systems with NVMe SSDs. By intelligently predicting the future I/O bandwidth requirement of containers based on past I/O service rates of I/O-active containers, and modifying the current Linux Cgroup implementation for better NUMAscalable performance, our scheme achieves highly accurate I/O resource sharing while reducing wasted I/O bandwidth. Based on a Linux kernel 4.0.4 implementation running on a 4-node NUMA multi-core systems with NVMe SSDs, our experimental results show that the proposed technique can efficiently share the I/O bandwidth of NVMe SSDs among multiple containers according to given I/O weights

Effect and Safety of Shihogyejitang for Drug Resistant Childhood Epilepsy

Objective. Herbal medicine has been widely used to treat drug resistant epilepsy. Shihogyejitang (SGT) has been commonly used to treat epilepsy. We investigated the effect and safety of SGT in children with drug resistant epilepsy. Design. We reviewed medical records of 54 patients with epilepsy, who failed to respond to at least two antiepileptic drugs and have been treated with SGT between April 2006 and June 2014 at the Department of Pediatric Neurology, I-Tomato Hospital, Korea. Effect was measured by the response rate, seizure-free rate, and retention rate at six months. We also checked adverse events, change in antiepileptic drugs use, and the variables related to the outcome. Results. Intent-to-treat analysis showed that, after six months, 44.4% showed a >50% seizure reduction, 24.1% including seizure-free, respectively, and 53.7% remained on SGT. Two adverse events were reported, mild skin rash and fever. Focal seizure type presented significantly more positive responses when compared with other seizure types at six months ( = 0.0284, Fisher's exact test). Conclusion. SGT is an effective treatment with excellent tolerability for drug resistant epilepsy patients. Our data provide evidence that SGT may be used as alternative treatment option when antiepileptic drug does not work in epilepsy children

Genetic Parameters of Milk β-Hydroxybutyric Acid and Acetone and Their Genetic Association with Milk Production Traits of Holstein Cattle

This study was conducted to estimate the genetic parameters of β-hydroxybutyrate (BHBA) and acetone concentration in milk by Fourier transform infrared spectroscopy along with test-day milk production traits including fat %, protein % and milk yield based on monthly samples of milk obtained as part of a routine milk recording program in Korea. Additionally, the feasibility of using such data in the official dairy cattle breeding system for selection of cows with low susceptibility of ketosis was evaluated. A total of 57,190 monthly test-day records for parities 1, 2, and 3 of 7,895 cows with pedigree information were collected from April 2012 to August 2014 from herds enrolled in the Korea Animal Improvement Association. Multi-trait random regression models were separately applied to estimate genetic parameters of test-day records for each parity. The model included fixed herd test-day effects, calving age and season effects, and random regressions for additive genetic and permanent environmental effects. Abundance of variation of acetone may provide a more sensitive indication of ketosis than many zero observations in concentration of milk BHBA. Heritabilities of milk BHBA levels ranged from 0.04 to 0.17 with a mean of 0.09 for the interval between 4 and 305 days in milk during three lactations. The average heritabilities for milk acetone concentration were 0.29, 0.29, and 0.22 for parities 1, 2, and 3, respectively. There was no clear genetic association of the concentration of two ketone bodies with three test-day milk production traits, even if some correlations among breeding values of the test-day records in this study were observed. These results suggest that genetic selection for low susceptibility of ketosis in early lactation is possible. Further, it is desirable for the breeding scheme of dairy cattle to include the records of milk acetone rather than the records of milk BHBA

The Relationship Between Thiamine Intake and Long Sleep Duration: Results From the Korea National Health and Nutrition Examination Survey

Objectives: Thiamine is thought to modify sleeping patterns, while alcohol use diminishes internal thiamine levels. We investigated the association between thiamine intake and sleep duration and explored possible heterogeneity in the effect according to alcohol use. Methods: In total, 15 384 participants aged 19-64 were obtained from the Korea National Health and Nutrition Examination Survey 2012-2016. Nutrient intake, including thiamine, was measured using a food frequency questionnaire. Sleep duration was measured by a self-reported questionnaire. The highest thiamine intake quartile was set as the reference group. Participants were divided into 3 groups, with 7-8 hours of daily sleep as a reference group and those who slept more or less than that as “oversleeping” and “insufficient sleeping,” respectively. Multivariate logistic regression was used, adjusting for socioeconomic, medical, and nutritional factors. Additionally, participants were stratified according to high-risk alcohol use defined by the World Health Organization standards on alcohol use. Results: Low thiamine intake was associated with oversleeping (Q3: odds ratio [OR], 1.06; 95% confidence interval [CI], 0.86 to 1.32; Q2: OR, 1.24; 95% CI, 0.99 to 1.55; Q1: OR, 1.49; 95% CI, 1.16 to 1.91) and showed a significant trend for higher ORs at lower intake levels (p-trend<0.001). The effect was stronger in the high-risk alcohol use group (Q1: OR, 1.78; 95% CI, 1.28 to 2.49). Conclusions: Low thiamine intake was associated with oversleeping, and alcohol use intensified that association. These results were found in a context where overt clinical symptoms due to thiamine deficiency are considered rare. More awareness of the potential relationship of thiamine intake with oversleeping and its related risks should be considered