Abstract: The present disclosure relates to a method of preparing a polymer, which includes: adding an alkyl-substituted aromatic vinyl-based monomer and a vinyl cyanide-based monomer to a reactor and initiating polymerization; and performing polymerization while continuously adding an alkyl-substituted aromatic vinyl-based monomer and a multifunctional initiator to the reactor, wherein the continuous addition of the alkyl-substituted aromatic vinyl-based monomer and the multifunctional initiator is initiated when a polymerization conversion rate is 10 to 30%, and the continuous addition of the alkyl-substituted aromatic vinyl-based monomer and the multifunctional initiator is terminated when a polymerization conversion rate is 70 to 80%.

Abstract: The present invention relates to an UML unification model system, in particular to a system for metamodeling transformation to guarantee interoperability between an UML model of IEC 61850 and an UML model of IEC 61970. According to the invention, all IEC 61970 smart grid application using IEC 61850 data source easily obtains interoperability between applications and actively react to change of international standard because application developers use data by referring to a single UML IEC 61850/61970 unified model and refer to a single UML model reflecting flexibly constant modification of IEC standard, if any.

Abstract: The present invention relates to a method for metamodeling unification, in particular to a method for metamodeling unification to guarantee interoperability between an UML model of IEC 61850 and an UML model of IEC 61970. According to the invention, all IEC 61970 smart grid application using IEC 61850 data source easily obtains interoperability between applications and actively react to change of international standard because application developers use data by referring to a single UML IEC 61850/61970 unified model and refer to a single UML model reflecting flexibly constant modification of IEC standard, if any.

Abstract: The present invention relates to a metamodeling unification system, in particular to a system for metamodeling unification to guarantee interoperability between an UML model of IEC 61850 and an UML model of IEC 61970. According to the invention, all IEC 61970 smart grid application using IEC 61850 data source easily obtains interoperability between applications and actively react to change of international standard because application developers use data by referring to a single UML IEC 61850/61970 unified model and refer to a single UML model reflecting flexibly constant modification of IEC standard, if any.