A New GARCH-Type Model

Qingfeng Liu 충남대학교 경영경제연구소 2010 경영경제연구 Vol.33 No.2

Liu와 Morimune(2005)는 일련의 양(+)의 충격 혹은 음(-)의 충격이 변동성에 미치는 영향을 포착하기 위하여 GARCH 모델을 확장하였다. 그리고 이 새로운 모델을 OGARCH 모델이라고 명명하였다. 그러나 OGARCH 모델에 대해 몇몇 연구자들이 충격의 함수형태에 문제가 있을 수 있음을 제기했다. 현재의 함수형태에서는 OGARCH 모델이 불안정할 수 있다는 것이다. 본 연구에서는 이러한 문제를 극복하기 위하여 충격에 대한 새로운 함수형태를 채택하여 모형을 수정하였다. 새로운 형태의 GARCH 모델은 일련의 양(+)의 충격 혹은 음(-)의 충격의 날짜 수가 변동성에 미치는 영향을 포착하도록 수정되었다. 본 연구는 새로운 모델을 SSEC, KS11, N225 지수들에 적용해 보았으며, 그 결과 상하이주식시장의 SSEC 지수를 분석하는데 특히 유용했음을 알 수 있었다. 또한 새로운 모형은 실증적 연구에서 OGARCH 모형과 GARCH 모형보다 더욱 좋은 결과를 보여주었다. Liu and Morimune (2005) expanded GARCH model to capture the effect of a consecutive number of positive or negative shocks on volatilities. They named that model OGARCH model. However, a shortcoming of OGARCH model on the function form was pointed out by some researchers. Due to this shortcoming, OGARCH model could be unstable. In this paper, in order to overcome this problem of OGARCH model, we modified it by adopting a different function of the spells of shocks. A new GARCH type model is established by means of capturing the effect on volatilities of the consecutive number of days of positive or negative shocks. The new model is applied to the SSEC, KS11 and N225 indices and is found particularly useful in analyzing the SSEC index of Shanghai market. Moreover, the new model performs better than OGARCH and GARCH model in the empirical study.

Influence of Microstructure and Mechanical Properties on Formability in High Strain Rate Rolled AZ31 Magnesium Alloy Sheets

Fubao Liu,Xiao Liu,Biwu Zhu,Hui Yang,Gang Xiao,Mingyue Hu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

High strain-rate rolling (≥ 10 s−1) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reductionof 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processessuch as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out onhigh strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties,microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was foundthat the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of highstrain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension andenhances strengthen of materials in front of crack tip.

The generalized Fermat type difference equations

Kai Liu,Lei Ma,Xiaoyang Zhai 대한수학회 2018 대한수학회보 Vol.55 No.6

This paper is to consider the generalized Fermat difference equations with different types which ever considered by Li \cite{li}, Ishizaki and Korhonen \cite{IK}, Zhang \cite{zhangjie} and Liu \cite{liuk4,11,1177,liu}, respectively. Some new observations and results on these equations will be given.

Inheritance and Development of Cultural Heritage of Chinese Architecture - Root-Exploring and Innovation of the Cultural Value of the Arch

Liu,Fu-long 한국조형디자인학회 2013 조형디자인연구 Vol.16 No.4

Chinese traditional architecture has a long-dated history. As one of the important architectural style of ancient cultural heritage, archway (square) building used since the Song Dynasty and now is the crowning touch to the composition of architectural space. First, the value of the arch is embodied in the inheritance and development of traditional culture, and cultural development of the arch is closely related to historical and cultural background of Chinese society; Second, as a traditional architectural form, the arch is one of the unique elements in entrance spaces, such as villages, temples, towns, royal gardens, memorial sites, tombs, etc. Meanwhile, the arch has become typical symbol of the entrance to residential area of foreign Chinese. Column, floor and frontal fang and span arch is the basic components of the arch. To cleverly constructed so that the arch stand leaving it emerged actual situation and white silhouette beauty. We can learn construction techniques and layout forms of Chinese traditional architecture, then explore the inheritance and development of the wisdom and culture of Chinese traditional architecture under contemporary perspective though the arch arts. The article takes the design of Baoji City Dai Jia-wan administrative square arch for example, explores the way of combining new technologies with traditional materials, meanwhile achieves harmony between large-scale pure stone arch and contemporary urban space, which is a useful practice about inheritance and innovation of traditional arch arts.

Study on the Thermal Decomposition of Waste Polystyrene in Motor Oil Using Microwave Energy

Liu, Xiao Yun,Kang, Tae Won 公州大學校 工學硏究院 生産技術硏究所 2003 論文集 Vol.11 No.-

A novel microwave-induced pyrolysis of waste polystyrene in motor oil was performed in quartz tube reactor. Different pyrolysis conditions were investigated, such as time range from 30 minutes to 1 hour and effective microwave power range from 180 to 250 watt. The distillate components were analyzed with GC-MS, and styrene, 1-methyl styrene, toluene, ethyl benzene were the four main products. Among these distillate products, styrene took over 70 percentages. Temperature of pyrolysis suing microwave was much lower than that of conventional thermal pyrolysis method.

The Molecular Mechanism of Safrole-induced DNA Adducts and its Role to Oral Carcinogenesis

Liu,Tsung-Yun 한국환경성돌연변이발암원학회 2003 한국환경성돌연변이·발암원학회지 Vol.23 No.3

Etude sur l'interpretation en Chine : Resultats et enjeux

LIU,Heping,XU,lun 한국통역번역학회 2010 FORUM Vol.8 No.2

Rainfall-induced Landslide Hazard Analysis Based on GIS in Yanbian Region, China

Liu,Xiu Xuan,Quan, He Chun,이병걸 대한공간정보학회 2017 대한공간정보학회지 Vol.25 No.4

This paper mainly studies landslide hazard in Yanbian region,8 landslide factors of soil moisture content, hydrogeology, land use type, slope, slope aspect, fault, river and rainfall are analyzed in the area of Yanbian region. Using the analytic hierarchy process (AHP), the relative weights of 8 landslide factors were obtained, and the internal weights of each factor were determined by the data; the rainfall factors were then divided into three categories such as average annual rainfall, average flood season rainfall, and the maximum average rainfall. And the comparison of the rainfall factors was made. Finally based on the results of these weights to the remote sensing technology(RS) and geographic information system(GIS) technology combined to evaluate its area, we are mapping the risk assessment area for landslide hazard in Yanbian region. According to the map analysis, figure in the dangerous hierarchies result in accordance with the historical landslides is better. At the same time. landslides and hazard area of statistical data analysis showed that the AHP method combined with GIS technology is suitable for promoting the Yanbian regional landslide hazard assessment.

COMMON STATIONARY POINTS OF MULTI-VALUED F-CONTRACTIONS WITH δ-DISTANCE

Liu1 Zeqing,Liu Ying,Kang Shin Min 경남대학교 기초과학연구소 2019 Nonlinear Functional Analysis and Applications Vol.24 No.1

Three common stationary point theorems for some multi-valued F-contractions with δ-distance in bounded complete metric spaces are proved. The results obtained in this paper are extended or are different from several results in the literature. Three nontrivial examples are given.

THE REPRESENTATION AND CONTINUITY OF A GENERALIZED METRIC PROJECTION ONTO HALF-SPACES IN BANACH SPACES

Liu1 Ruijuan,Liu Chunyan,Zhang Zihou 경남대학교 기초과학연구소 2019 Nonlinear Functional Analysis and Applications Vol.24 No.1

Let C be a closed bounded convex subset of a real Banach space X with 0 as its interior point and pc the Minkowski functional generated by the set C. For a nonempty set G in X and x ∈ X, g_0 ∈ G is called the generalized best approximation to x from G if p_c(g_0 − x) ≤ p_c(g − x) for all g ∈ G. In this paper, we will give a distance formula under p_C from a point to a half-space K_{x^∗_0,c} = {x ∈ X : x^∗_0(x) ≤ c} in Banach space and investigate the continuity of this generalized metric projection, extending corresponding results for the case of norm.