본 연구에서는 고체추진기관의 2차원 축대칭 FSI 해석에서 CSS 및 ISS 기법의 수치 안정성을 고찰하였다. 이를 위하여 CSS 및 ISS 기법을 2차원 축대칭 FSI 수치해석 알고리즘에 구현한 프로그램을 작성하고, 이를 ACM 및 BCM 고체추진기관의 복합거동 해석에 사용하였다. 해석 결과들을 비교 분석하여 ISS 기법이 고체추진기관 FSI 해석의 수치 안정성 개선에 효과적인지 검토하였다. 연구결과, ISS 기법을 적용한 FSI 해석은 시스템 시간간격이 작아질수록 수치적 수렴성을 보이며, CSS 기법과 다르게 시간이 진행되어도 수치해의 진동이 발산하지 않는 것을 확인할 수 있었다. 이를 통하여 ISS 기법을 사용하면 ACM 및 BCM의 FSI 해석에 CSS 기법을 이용할 시 나타나는 수치 불안정성을 개선할 수 있음을 확인하였다.

Korean particle <-ka> has long been simply known as a subject marker. But subjects without <-ka> are very often realized in sentences, and they are always accompanied by the constraint on the correspondence between linear order and thematic role of the constituents. Besides, the subjects without <-ka> are sometimes not allowed in accordance with several syntactic/semantic properties of the subjects and their predicates, in very complicated ways. Traditional view on <-ka> cannot explain these phenomena. In this article, we adopt Bowers (2001)'s PrP Hypothesis and many-folded predicate structure to solve these puzzles. It's claimed that [Spec, PrP] is the position of the optional realization of <-ka>. The nominal which merges with <-ka> has theta positions of [ComP, VP] or [Spec, PrP], and its case is licensed in-situ through agreement under c-command of an Agr <-si/∅> which is placed directly after a verb stem as a subject honorific marker, in derivations of finite clauses. The optionally projected morphological features of <-ka> attract the nominal, and the lexical meaning of <-ka>(focus etc.) is added after the merge. It is the structurally determined position of <-ka> and the theta positions varied by the argument structures of different predicates that explain why some subjects without <-ka> are not allowed and the linear orders of other constructions are constrained. On the other hand, the projection and merge of <-ka> is necessary when the nominals are semantic restrictions of operators of which arguments are propositions. It seems quite natural that the meaning of <-ka>(focus etc.) is necessarily added to the restrictions because the semantic constituents contain important informations which prevent domains of operation from expanding massively.