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Search Results: 1 - 10 of 7439 matches for " Sang-Gyoo SIM "
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Anonymous Authorship Control for User-Generated Content
Suk-Bong LEE,Sang-Gyoo SIM,Yeo-Jin KIM,Yun-Sang OH
Journal of Systemics, Cybernetics and Informatics , 2007,
Abstract: User-Generated Content (UGC) is opening up new large market in content services, and more and more people are visiting web sites to share and enjoy UGCs. These trends make many authors to move into online. Authors want to conserve their authorship and expect to publish their UGC anonymously in cases. To meet the requirements, we propose a new authorship control model based on watermarking and metadata. Authors can embed their authorship into their UGC with identities or with anonym. Even though an author publishes his UGC anonymously, he can prove his authorship without unveiling his identity via 5 methods utilizing the proposed authorship model. The proposed model and methods need no TTP and are robust even based on fragile underlying watermarking scheme.
A Certain Subclass of Analytic Functions  [PDF]
Young Jae Sim, Oh Sang Kwon
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.24038
Abstract: In the present paper, we introduce a class of analytic functions in the open unit disc by using the analytic function qα(z)=3/(3+(α-3)z-αz2), which was investigated by Sokó? [1]. We find some properties including the growth theorem or the coefficient problem of this class and we find some relation with this new class and the class of convex functions.
A Certain Subclass of Analytic Functions with Bounded Positive Real Part  [PDF]
Young Jae Sim, Oh Sang Kwon
Advances in Pure Mathematics (APM) , 2013, DOI: 10.4236/apm.2013.34059

For real numbers α and β such that 0α1β, we denote by T(α,β) the class of normalized analytic functions which satisfy \"\"\"\", where U denotes the open unit disk. We find some relationships involving functions in the class T(α,β). And we estimate the bounds of coefficients and solve Fekete-Szego problem for functions in this class. Furthermore, we investigate the bounds of initial coefficients of inverse functions or bi-univalent functions.

Rational Engineering of Enzyme Allosteric Regulation through Sequence Evolution Analysis
Jae-Seong Yang ,Sang Woo Seo ,Sungho Jang,Gyoo Yeol Jung ,Sanguk Kim
PLOS Computational Biology , 2012, DOI: 10.1371/journal.pcbi.1002612
Abstract: Control of enzyme allosteric regulation is required to drive metabolic flux toward desired levels. Although the three-dimensional (3D) structures of many enzyme-ligand complexes are available, it is still difficult to rationally engineer an allosterically regulatable enzyme without decreasing its catalytic activity. Here, we describe an effective strategy to deregulate the allosteric inhibition of enzymes based on the molecular evolution and physicochemical characteristics of allosteric ligand-binding sites. We found that allosteric sites are evolutionarily variable and comprised of more hydrophobic residues than catalytic sites. We applied our findings to design mutations in selected target residues that deregulate the allosteric activity of fructose-1,6-bisphosphatase (FBPase). Specifically, charged amino acids at less conserved positions were substituted with hydrophobic or neutral amino acids with similar sizes. The engineered proteins successfully diminished the allosteric inhibition of E. coli FBPase without affecting its catalytic efficiency. We expect that our method will aid the rational design of enzyme allosteric regulation strategies and facilitate the control of metabolic flux.
A Subclass of Meromorphic Close-to-Convex Functions of Janowski's Type
Young Jae Sim,Oh Sang Kwon
International Journal of Mathematics and Mathematical Sciences , 2012, DOI: 10.1155/2012/682162
Abstract: We introduce a subclass of functions which are analytic in the punctured unit disk and meromorphically close-to-convex. We obtain some coefficients bounds and some argument and convolution properties belonging to this class. 1. Introduction Let be the set of all analytic functions on the open unit disk , and let be the subclass of which contains the functions normalized by and . A function is said to be starlike of order if and only if for some and for all . The class of starlike functions of order is denoted by . If and are analytic in , we say that is subordinate to , written as follows: if there exists a Schwarz function , which is analytic in with such that In particular, if the function is univalent in , the above subordination is equivalent to The Hadamard product (or convolution) of two series is defined by For a convex function , it follows from Alexander’s Theorem that is a starlike function. In view of the identity , it is then clear that the classes of convex and starlike functions can be unified by considering functions satisfying is starlike for a fixed function . Though the convolution of two univalent (or starlike) functions does not need be univalent, it is well-known that the classes of starlike, convex, and close-to-convex functions are closed under convolution with convex functions. These results were later extended to convolution with prestarlike functions. For , the class of prestarlike functions of order is defined by while consists of satisfying . By using the convex hull method [1, 2] and the method of differential subordination [3], Shanmugam [4] introduced and investigated convolution properties of various subclasses of analytic functions. Ali et al. [5] and Supramaniam et al. [6] investigated these properties for subclasses of multivalent starlike and convex functions. And Chandrashekar et al. [7] also investigated these properties for the functions with respect to symmetric points, conjugate, or symmetric conjugate points. More results using the convex hull method and the method of differential subordination can be found in [8, 9]. Let denote the class of all univalent meromorphic functions normalized by which are analytic in the punctured unit disk We denote by the subclass of consisting of formed by which are meromorphic starlike of order in . In particular, we denote by , when . Also, a function of the form (1.9) is said to be meromorphic close-to-convex in if there is a in such that We denote the set of functions close-to-convex in . In a recent paper, Gao and Zhou [10] introduced an interesting subclass of the analytic
Bis-sulfonic Acid Ionic Liquids for the Conversion of Fructose to 5-Hydroxymethyl-2-furfural
Sang Eun Sim,Sunjeong Kwon,Sangho Koo
Molecules , 2012, DOI: 10.3390/molecules171112804
Abstract: Homogenous bis-sulfonic acid ionic liquids (1 mol equiv.) in DMSO (10 mol equiv.) at 100 °C efficiently mediated the conversion of D-fructose into 5-hydroxymethyl-2-furfural in 75% isolated yield, which was roughly a 10% increment compared to the case of the mono-sulfonic acid ionic liquids.
On Certain Classes of Convex Functions
Young Jae Sim,Oh Sang Kwon
International Journal of Mathematics and Mathematical Sciences , 2013, DOI: 10.1155/2013/294378
Abstract: For real numbers and such that , we denote by the class of normalized analytic functions which satisfy the following two sided-inequality: where denotes the open unit disk. We find some relationships involving functions in the class . And we estimate the bounds of coefficients and solve the Fekete-Szeg? problem for functions in this class. Furthermore, we investigate the bounds of initial coefficients of inverse functions or biunivalent functions. 1. Introduction Let denote the class of analytic functions in the unit disc which is normalized by Also let denote the subclass of which is composed of functions which are univalent in . And, as usual, we denote by the class of functions in which are convex in . We say that is subordinate to in , written as , if and only if for some Schwarz function such that If is univalent in , then the subordination is equivalent to Definition 1. Let and be real numbers such that . The function belongs to the class if satisfies the following inequality: It is clear that . And we remark that, for given real numbers and , if and only if satisfies each of the following two subordination relationships: Now, we define an analytic function by The above function was introduced by Kuroki and Owa [1], and they proved that maps onto a convex domain conformally. Using this fact and the definition of subordination, we can obtain the following lemma, directly. Lemma 2. Let and . Then if and only if And we note that the function , defined by (7), has the form where For given real numbers and such that , we denote by the class of biunivalent functions consisting of the functions in such that where is the inverse function of . In our present investigation, we first find some relationships for functions in bounded positive class . And we solve several coefficient problems including Fekete-Szeg? problems for functions in the class. Furthermore, we estimate the bounds of initial coefficients of inverse functions and bi-univalent functions. For the coefficient bounds of functions in special subclasses of , the readers may be referred to the works [2–4]. 2. Relations Involving Bounds on the Real Parts In this section, we will find some relations involving the functions in . And the following lemma will be needed in finding the relations. Lemma 3 (see Miller and Mocanu [5, Theorem ]). Let be a set in the complex plane and let be a complex number such that . Suppose that a function satisfies the condition for all real and all . If the function defined by is analytic in and if then in . Theorem 4. Let , and Then Proof. First of all, we put and
Stochastic Convective Wave Equation in Two Space Dimension
Sang-Hyeon Park,Imbo Sim
Mathematics , 2014,
Abstract: We study the convective wave equation in two space dimension driven by spatially homogeneous Gaussian noise. The existence of the real-valued solution is proved by providing a necessary and sufficient condition of Gaussian noise source. Our approach is based on the mild solution of the convective wave equation which is constructed by Walsh's theory of martingale measures. H\"older continuity of the solution is proved by using Green's function and Kolmogorov continuity theorem.
Analysis of PML Method for Stochastic Convected Helmholtz Equation
Sang-Hyeon Park,Imbo Sim
Mathematics , 2015,
Abstract: We propose and analyze the perfectly matched layer (PML) method for the time-harmonic acoustic waves driven by the white noise source in the presence of the uniform flow. A PML is an artificial absorbing layer commonly used to truncate computational regions to solve problems in unbounded domains. We study a modification of PML method based on B\'ecache et. al. A truncated domain problem for stochastic convected Helmholtz equation in the infinite duct is constructed by applying PMLs. Our PML method omits the instability of inverse upstream modes in the PML. Moreover, a suitable jump condition on boundaries between computational domain and PMLs is not required. We analyze the stochastic error generated by truncations of the domain. Thus the convergence analysis of the solution is provided in the sense of mean-square.
Planning and Dosimetric Comparisons of IMRT Lung Cancers with Three Advanced Optimization Algorithms  [PDF]
Yie Chen, Jie Qu, Jack Yang, Mitch Weiss, Sang Sim, Xiongfei Liao
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2013, DOI: 10.4236/ijmpcero.2013.22008

Purpose: To evaluate planning quality and dosimetric differences of clinically deliverable Intensity-modulated Radiation Therapy lung plans generated from Tomotherapy, Pinnacle3, and RayStationTM treatment planning systems. Method and Materials: Ten patients diagnosed with non-small-cell lung carcinoma (NSCLC) previously treated with plans on Pinnacle using Direct Machine Parameter Optimization were randomly selected and re-planned with Tomotherapy dose volume constraints and same beam geometry with RayStation Multi Criteria Optimization (MCO) equivalent uniform dose (EUD) or dose volume constraints, respectively.  Prescription was established as 60 Gy to cover > 95% of PTV. Planning outcomes such as D95 (95% of volume of PTV receiving the prescribed dose), D5, D33, mean heart and lung doses, V20 (volume of lung receiving 20 Gy), and max cord dose of 1cm3 were evaluated according to our departmental clinical protocols. Conformity index (CI = PTV / prescription isodose volume) and homogeneity index (HI = D5/D95) were also reported simultaneously. All plans were successfully

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