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Search Results: 1 - 10 of 2240 matches for " Sangho Oh "
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Stability of nets of quadrics in $\mathbb{P}^5$ and associated discriminants
Sangho Byun
Mathematics , 2015,
Abstract: Let $S$ be a complete intersection surface defined by a net $\Lambda$ of quadrics in $\mathbb P^5$. In this paper we analyze GIT stability of nets of quadrics in $\mathbb P^5$ up to projective equivalence, and discuss some connections between a net of quadrics and the associated discriminant sextic curve. In particular, we prove that if $S$ is normal and the discriminant $\Delta(S)$ of $S$ is stable then $\Lambda$ is stable. And we prove that if $S$ has the reduced discriminant and $\Delta(S)$ is stable then $\Lambda$ is stable. Moreover, we prove that if $S$ has simple singularities then $\Delta(S)$ has simple singularities.
An ambitious step to the future desalination technology: SEAHERO R&D program (2007–2012)
Suhan Kim,Byung Soo Oh,Moon-Hyun Hwang,Seungkwan Hong,Joon Ha Kim,Sangho Lee,In S. Kim
Applied Water Science , 2011, DOI: 10.1007/s13201-011-0003-4
Abstract: In Republic of Korea, seawater engineering and architecture of high efficiency reverse osmosis (SEAHERO) research and development (R&D) program started from 2007 to lead the top seawater reverse osmosis (SWRO) plant technologies for desalination with the fund of US $165 million for 6 years including test-bed plant construction. There are three technical strategies for SEAHERO R&D program called 3L, which represents large scale, low fouling, and low energy, respectively. Large scale means design, construction, and operation of the largest unit SWRO train [daily water production rate = 8 MIGD (36,000 m3/day)] in the world. Low-fouling strategy targets the decrease of RO membrane fouling by 50%. The specific target for low energy is total energy consumption of whole SWRO plant (including intake, pretreatment, SWRO systems, and so on) less than 4 kWh/m3. The core parts for SWRO plant, such as 16 in. diameter RO membrane and energy recovery device, were developed and will soon be introduced to a test-bed including the largest unit SWRO train. The next step of SEAHERO is real field scale test-bed application of the unit technologies developed for the past 4 years (2007–2010) such as strategic pretreatment, energy-saving technology, and reliable system monitoring.
Computational Prediction of Protein-Protein Interactions of Human Tyrosinase
Su-Fang Wang,Sangho Oh,Yue-Xiu Si,Zhi-Jiang Wang,Hong-Yan Han,Jinhyuk Lee,Guo-Ying Qian
Enzyme Research , 2012, DOI: 10.1155/2012/192867
Abstract: The various studies on tyrosinase have recently gained the attention of researchers due to their potential application values and the biological functions. In this study, we predicted the 3D structure of human tyrosinase and simulated the protein-protein interactions between tyrosinase and three binding partners, four and half LIM domains 2 (FHL2), cytochrome b-245 alpha polypeptide (CYBA), and RNA-binding motif protein 9 (RBM9). Our interaction simulations showed significant binding energy scores of ?595.3?kcal/mol for FHL2, ?859.1?kcal/mol for CYBA, and ?821.3?kcal/mol for RBM9. We also investigated the residues of each protein facing toward the predicted site of interaction with tyrosinase. Our computational predictions will be useful for elucidating the protein-protein interactions of tyrosinase and studying its binding mechanisms. 1. Introduction Tyrosinase (EC 1.14.18.1) is ubiquitously distributed in organisms and is a critical enzyme involved in melanin production, with multiple catalytic functions in pigment production [1–3]. Tyrosinase mutations are directly linked to pigmentation disorders in mammals [4, 5] and can cause a browning effect in vegetables [6, 7]. In addition, tyrosinase participates in cuticle formation in insects [8, 9]. In mammals, tyrosinase is a bifunctional enzyme that first converts tyrosine to DOPA and then to DOPA quinone, which is further cyclized and oxidized to produce melanin pigments [10]. The human tyrosinase protein contains two Cu2+-binding sites, two cysteine rich regions, a signal peptide region, a transmembrane anchor domain, and an EGF motif [11]. Two Cu2+ ions in the active site of tyrosinase are coordinated by three histidine residues each and are essential for the enzyme’s catalytic activity [12]. Furthermore, the presence of Cu2+ in the active site of tyrosinase is observed across numerous organisms [13]. Therefore, chelation of tyrosinase Cu2+ by synthetic compounds or agents from natural sources has been targeted as a way to block tyrosinase catalysis for medicinal purposes, darkening problems in agricultural products, and cosmetic interests [14, 15]. As the crystallographic structure of tyrosinase has been gradually elucidated, insights into its catalytic mechanisms and active site have also been revealed [16–18]. However, while the catalytic mechanism of tyrosinase-mediated melanin pigment production has been well studied, the relationship between tyrosinase enzyme activity and protein interactions has not been fully elucidated, despite several reports of interacting proteins for tyrosinase [19–22].
Localization with a Mobile Beacon in Underwater Acoustic Sensor Networks
Sangho Lee,Kiseon Kim
Sensors , 2012, DOI: 10.3390/s120505486
Abstract: Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node’s location and then the node’s location is determined through the weighted mean of all the potential locations with the weights computed based on residuals.
Health care utilization among Medicare-Medicaid dual eligibles: a count data analysis
Sangho Moon, Jaeun Shin
BMC Public Health , 2006, DOI: 10.1186/1471-2458-6-88
Abstract: The household component of the nationally representative Medical Expenditure Panel Survey (MEPS) 1996–2000 is used for the analysis. Total 8,262 Medicare beneficiaries are selected from the MEPS data. The Medicare beneficiary sample includes individuals who are covered by Medicare and do not have private health insurance during a given year. Zero-inflated negative binomial (ZINB) regression model is used to analyse the count data regarding health care utilization: office-based physician visits, hospital inpatient nights, agency-sponsored home health provider days, and total dental visits.Dual eligibility is positively correlated with the likelihood of using hospital inpatient care and agency-sponsored home health services and the frequency of agency-sponsored home health days. Frequency of dental visits is inversely associated with dual eligibility. With respect to racial differences, dually eligible Afro-Americans use more office-based physician and dental services than white duals. Asian duals use more home health services than white duals at the 5% statistical significance level. The dual eligibility programs seem particularly beneficial to Afro-American duals.Dual eligibility has varied impact on health care utilization across service types. More utilization of home healthcare among dual eligibles appears to be the result of delayed realization of their unmet healthcare needs under the traditional Medicare-only program rather than the result of overutilization in response to the expanded benefits of the dual eligibility program. The dual eligibility program is particularly beneficial to Asian and Afro-American duals in association with the provision of home healthcare and dental benefits.It has been an important financial issue in the Medicare system that health care expenses of dually eligible beneficiaries (DEB) are much higher than those of Medicare-only beneficiaries (MOB). Total health expenditures for the dually eligible beneficiaries are more than double
A Geometric Mean of Parameterized Arithmetic and Harmonic Means of Convex Functions
Sangho Kum,Yongdo Lim
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/836804
Abstract:
A Geometric Mean of Parameterized Arithmetic and Harmonic Means of Convex Functions
Sangho Kum,Yongdo Lim
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/836804
Abstract: The notion of the geometric mean of two positive reals is extended by Ando (1978) to the case of positive semidefinite matrices and . Moreover, an interesting generalization of the geometric mean of and to convex functions was introduced by Atteia and Ra?ssouli (2001) with a different viewpoint of convex analysis. The present work aims at providing a further development of the geometric mean of convex functions due to Atteia and Ra?ssouli (2001). A new algorithmic self-dual operator for convex functions named “the geometric mean of parameterized arithmetic and harmonic means of convex functions” is proposed, and its essential properties are investigated. 1. Introduction The notion of geometric means is extended by Ando [1] to the case of positive semidefinite matrices and as the maximum of all for which is positive semidefinite. If is invertible, then . The geometric mean appears in the literature with many applications in matrix inequalities, semidefinite programming (scaling point [2, 3]), geometry (geodesic middle [4, 5]), statistical shape analysis (intrinsic mean [6, 7]), and symmetric matrix word equations [8–10]. The most important property of the geometric mean is that it has a Riccati matrix equation as the defining equation. The geometric mean is the unique positive definite solution of the Riccati matrix equation . An interesting generalization of the geometric mean to convex functions was introduced by Atteia and Ra?ssouli [11] with a different viewpoint of the convex analysis. The natural idea to make an extension from positive semidefinite matrices to convex functions is nothing but the association of a positive semidefinite matrix with the quadratic convex function . Atteia and Ra?ssouli [11] provided a general algorithm to construct the (self-dual) geometric mean and the square root of convex functions. As pointed out in [12], self-dual operators are important in convex analysis and also arise in PDE. The present work aims at providing a further development of the geometric mean of the convex functions mentioned above. We develop a new algorithmic self-dual operator for convex functions named “the geometric mean of parameterized arithmetic and harmonic means of convex functions” by exploiting the proximal average of convex functions by Bauschke et al. [13] and investigate its essential properties such as limiting behaviors, self-duality, and monotonicity with respect to parameters. While doing so, we will see that the geometric mean due to Atteia and Ra?ssouli [11] can be interpreted as an element of “the geometric mean of parameterized
Stability of hypersurface sections of quadric threefolds
Sangho Byun,Yongnam Lee
Mathematics , 2014,
Abstract: Let $S$ be a complete intersection of a smooth quadric 3-fold $Q$ and a hypersurface of degree $d$ in ${\mathbb P}^4$. In this paper we analyze GIT stability of $S$ with respect to the natural $G=SO(5, {\mathbb C})$-action. We prove that if $d\ge 4$ and $S$ has at worst semi-log canonical singularities then $S$ is $G$-stable. Also, we prove that if $d\ge 3$ and $S$ has at worst semi-log canonical singularities then $S$ is $G$-semistable.
CMOS Delay and Power Model Equations for Simultaneous Transistor and Interconnect Wire Analysis and Optimization
Sangho Lee,Edwin W. Greeneich
VLSI Design , 2002, DOI: 10.1080/1065514021000012237
Abstract: Efficient, generalized delay and power equations are proposed for large scale CMOS circuit analysis and optimization achieved by transistor and interconnect wire minimization. The proposed model equations are used to analyze the entire power-delay trade-off with less complexity and faster computation time. New equations can be adopted to perform the optimization of transistor and interconnect wire size concurrently. A single stage CMOS circuit and a clock generation block fabricated in 0.48 um CMOS process are given as experimental examples.
Preservice Teachers’ Sense of Efficacy and Its Sources  [PDF]
Sunjin Oh
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.23037
Abstract: The purpose of this study was to examine several potential sources of preservice teachers’ perceptions of their teaching efficacy during their reading and writing lessons. More specifically, the study explored the relationship between the sources of preservice teachers’ self-efficacy and teachers’ perception of efficacy in the areas of instructional strategies, classroom management, and student engagement. Forty-three preservice teachers in pre-literacy methods courses and fourteen in post-literacy methods courses completed the survey, which consisted of the Teacher Sense of Efficacy Scale (TSES) and Teaching Efficacy Sources Inventory. Paired t-test results showed that preservice teachers’ teaching efficacy increased in the three subscales of instructional strategies, classroom management, and student engagement by the end of the literacy method courses. Efficacy for instructional strategies, classroom management, and student engagement were highly intercorrelated with each other in the pre-test data. The results of multiple regression analysis indicated that personality characteristics, capabilities, motivation, enactive mastery experiences with social/verbal persuasion, and physiological/affective state were significant predictors when efficacy for classroom management was the dependent variable in the post-test data. Findings of this study revealed that preservice teachers’ personality, motivation, and capabilities were one of the important sources to improve their teaching efficacy, in congruence with previous research (Poulou, 2007; Yeung & Watkins, 2000).
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