• 대한수학회지
• /
• 제43권4호
• /
• pp.871-883
• /
• 2006

We show that the Auslander index is the same as the column invariant over Gorenstein local rings. We also show that Ding's conjecture ([13]) holds for an isolated non-Gorenstein ring A satisfying a certain condition which seems to be weaker than the condition that the associated graded ring of A is Cohen-Macaulay.

• 통합자연과학논문집
• /
• 제10권4호
• /
• pp.240-244
• /
• 2017

We study the behavior of some invariants under completion. We also give a counterexample, which is the same as a counterexample to Ding's Conjecture, to Koh-Lee's Conjecture.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2003년도 춘계학술대회 논문집
• /
• pp.123-124
• /
• 2003

Fishman and Larson (1987) derived tropical tropospheric column ozone by subtracting stratospheric column ozone measured by the Stratospheric Aerosol and Gas Experiment (SAGE) from total column ozone obtained by the Total Ozone Mapping Spectrometer (TOMS). Later, the Convective Cloud Differential (CCD) method (Ziemke et al., 1998) indicated stratospheric ozone is invariant with longitude and concluded the zonal variation of total ozone determines the zonal variation of tropospheric ozone. (omitted)

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.680-684
• /
• 2005

This paper presents a data-based stability analysis of a MIMO linear time-invariant discrete-time system, as an extension of the previous results for a SISO system. In the MIMO case, a similar discussion as in the case of a SISO system is also applied, except that an augmented input and output space is considered whose dimension is determined in relation to both the orders of the input and output vectors and the numbers of inputs and outputs. As certain subspaces of the input and output space, both output data space and closed-loop data space are defined, which contain all the behaviors of a system, respectively, with zero input in open-loop and with a control input in closed-loop. Then, we can derive the data-based stability conditions, in which the open-loop stability can be checked by using a data matrix whose column vectors span the output data space and the closed-loop stability can also be checked by using a data matrix whose column vectors span the closed-loop data space.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
• /
• pp.238-243
• /
• 1986

Distillation columns are widely used in almost every chemical plant. The use of multivariable control for such units is attractive because of the strong interactions exhibited between outputs and inputs and the desire to control simultaneously both top and bottom products. In this research design of a robust multivariable controller for distillation column was considered; output feedback controller with proportional and integral modes was designed using pole assignment. The transfer function matrix was obtained by fitting the step response realtions between single input double output pairs of variables. This matrix was then converted to linear time invariant state space model by multivariable realization technique. With the proposed multivariable proportional and integral controller applied to the process, the result of the digital computer simulation showed a good performance of asymtotic tracking. The limited experimental performance of this multivariable control was compared with the result from simulation. It was found that the proposed controller performed satisfactorily for the distillation column which separated binary mixture of methanol and water.

• 대한수학회보
• /
• 제44권4호
• /
• pp.871-878
• /
• 2007

We define a numerical invariant $row_{CM}(A)$ over Cohen-Macaulay local ring A, which is related to rows of the presenting matrices of maximal Cohen-Macaulay modules without free summands. We show that $row(A)=row_{CM}(A)$ for a Cohen-Macaulay(not necessarily Gorenstein) local ring A.

• 한국항만학회지
• /
• 제9권1호
• /
• pp.45-56
• /
• 1995

Investigation of the physical behavior of dredged material disposal in coastal water includes estimations of water column concentration in the receiving water, exposure time, the initial deposition pattern as well as thickness of material at the dumping fields near the estuary area. Calculation based on vertical setting and horizontal advection of single particles ignore the effects of bulk properties of the disposed material, vertical and horizontal diffusion, and material dilution due to the entrainment of ambient water during descent. This paper focuses on the spatial and temporal changes in the dumping fields for the water column and bottom at a hypothetically confined coastal water, where the ambient time-invariant velocity and density profiles are applied, within the initial time period following the instantaneous release of the dredged material. This model accounts the behavior of material after release divided into three phases: convective descent, dynamic collapse and long-term passive dispersion

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권9호
• /
• pp.3782-3796
• /
• 2020

A three-dimensional (3D) reconstruction is an important research area in computer vision. The ability to detect and match features across multiple views of a scene is a critical initial step. The tracking matrix W obtained from a 3D reconstruction can be applied to structure from motion (SFM) algorithms for 3D modeling. We often fail to generate an acceptable number of features when processing face or medical images because such images typically contain large homogeneous regions with minimal variation in intensity. In this study, we seek to locate sufficient matching points not only in general images but also in face and medical images, where it is difficult to determine the feature points. The algorithm is implemented on an adaptive threshold value, a scale invariant feature transform (SIFT), affine SIFT, speeded up robust features (SURF), and affine SURF. By applying the algorithm to face and general images and studying the geometric errors, we can achieve quasi-dense matching points that satisfy well-functioning geometric constraints. We also demonstrate a 3D reconstruction with a respectable performance by applying a column space fitting algorithm, which is an SFM algorithm.

• 대한화학회지
• /
• 제37권12호
• /
• pp.1035-1046
• /
• 1993

몇 가지 iron(III)porphyrin 착화합물을 합성하고, 이들에 대하여 역상 액체 크로마토그래피에서의 최적 분리조건 및 용리거동을 조사하였다. 분리관, 흐름속도, 용리액의 조성 등을 변화시킨 실험에서 분리관은 NOVA-PAK $C_{18}$, 용리액은 methanol/water의 이성분 혼합용매를 적당히 조절하였을 때 용량인자가 최적 분리조건인 $0{\leq}logk'{\leq}1$ 범위를 만족시켰다. 용리거동에 관련된 인자들로는 용리액의 세기, 분포비$(D_c)$ 및 분리관의 온도변화에 따른 엔탈피(${\Delta}H^{\circ}$), 엔트로피(${\Delta}S^{\circ}$), 보정온도($\beta$)를 조사하여 분리 메카니즘을 규명하였다. 이성분 용매계에서 용리 세기 및 물의 부피분율과 용량인자(logk')와의 관계를 조사한 결과 이들간에는 직선성이 잘 성립되었으며, 부피비와 용량인자와의 관계에서도 비교적 직선성을 잘 나타내었다. 이러한 결과로부터 시료의 용리 메카니즘이 소용매성 효과에 기인하고 있음을 확인할 수 있었다. 또한 열역학적인 방법으로 용리거동을 조사하기 위하여, van't Hoff plot으로부터 엔탈피, 엔트로피를 구하였다. 엔탈피와 용량인자와의 상관관계를 조사한 결과 iron(III)porphyrin 착화합물과 정지상과의 상호작용은 온도변화에 과계없이 일정함을 알 수 있었고, 정지상과의 소용매성 결합 과정은 등평형 거동을 나타내었다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.253-256
• /
• 2006

When the background tropospheric ozone column over the Pacific Ocean is subtracted from the latitudinal total ozone distribution, the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the T-P method. It suggests that the CCD method can be replaced by the simple T-P method. However, the tropical Atlantic paradox exists in the results of both the CCD and T-P methods during the northern burning season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and T-P methods by using the SAGE measurements (e.g. TSA method) and the SHADOZ ozonesoundings (e.g. T-S method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the T-SA and T-S methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and T-P methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.