• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
• /
• pp.53-60
• /
• 2001

Meshfree methods have been attracting issue as computational methods during past a few years. Nowadays, various meshfree methods such as EFGM, RKPM h-p cloud method and etc. were developed and applied in engineering problems. But, most of them were not truly meshless method because background mesh of cell was required for the spatial integration of a weak form. A nodal integration is required for truly meshless methods but it is known that this method gives a little unstable and incorrect solutions. In this paper, an improvement scheme of the existed nodal integration which the weak form can be simply integrated without any stabilization term is proposed. Numerical tests show that the proposed method is more convenient and gives more correct solutions than the previous method.

• 한국정보통신학회논문지
• /
• 제7권7호
• /
• pp.1498-1508
• /
• 2003

기업은 내부의 정보체계를 프로세스나 워크플로우 중심으로 통합함으로써 고객의 요구가 달성되기까지의 과정과 시간을 최소화하고 고객의 가치를 극대화하여 기업의 시장 경쟁력을 확보하려고 한다. 그러한 통합 노력은 ERP, CORBA, DCOM둥 패키지 또는 동기식의 강력한 결합(Synchronous & Tightly-Coupled)방식에서 시작하여, 인터넷 기술의 발전으로SCM(Supply Chain Management), CRM(Customer Relationship Management), e-Business, B2B(Business-to-Business)둥이 확대됨으로써 이 기종의 다양한 플랫폼을 가진 기업간에 효율적인 통합이 가능토록 MOM(Message-Oriented Middleware)을 기반으로 한 비동기식의 유연한 결합(Asynchronous & Loosely-Coupled)방식인EAI(Enterprise Application Integration)나 웹서비스(Web Services)로 발전하고 있다. 하나의 프로세스는 기업의 목적달성을 위한 하나의 장기 트랜잭션으로 간주될 수 있다. 동기식 결합보다는 비동기식 결합 방식에서 트랜잭션의 효율적인 관리가 더욱 중요한 데, 본 고에서는 기존의 2-Phase Commit(2PC) 방식보다 트랜잭션의 효과적인 모니터링과 처리자원 낭비를 감소시킬 수 있는 방법으로써 “Classify Phase”를 추가한 3PC Protocol를 제시하고 기존의 처리 방식과 비교하여 개선된 부분을 확인해본다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
• /
• pp.254-257
• /
• 2007

This paper presents an examination of the spatial integration method for extracting the RCS of a trihedral corner reflector from SAR images for SAR external calibration. An exact external radiometric calibration technique is required for extracting an exact calibration constant. Therefore, we examine the accuracy of the spatial integration method, which is commonly used for the SAR external radiometric calibration. At first, an SAR image for a trihedral corner reflector is simulated with a high-resolution SAR impulse response with a known theoretical RCS of the reflector, and a background clutter image for the high resolution SAR system is also generated. Then, a SAR image in a high resolution is generated for a trihedral comer reflector located on a background clutter by superposition of the two SAR images. The radar cross section of a trihedral corner reflector in the SAR image is retrieved by integrating the radar signals of the pixels adjacent to the reflector for various size of the integration area. By comparison of the measured RCS by the integration method and the theoretical RCS of the reflector, the effect of the size of the integration area on the extraction of the calibration constant is examined.

• 제어로봇시스템학회논문지
• /
• 제19권2호
• /
• pp.140-145
• /
• 2013

This paper proposes an efficient integration method for GPS (Global Positioning System) and INS (Inertial Navigation System). To obtain accuracy and computational conveniency at the same time with low cost global positioning system receivers and micro mechanical inertial sensors, a new mechanization method and a new filter architecture are proposed. The proposed mechanization method simplifies velocity and attitude computation by eliminating the need to compute complex transport rate related to the locally-level frame which continuously changes due to unpredictable vehicle motions. The proposed filter architecture adopts two heterogeneous filters, i.e. position-domain Hatch filter and velocity-aided Kalman filter. Due to distict characteristics of the two filters and the distribution of computation into the two hetegrogeneous filters, it eliminates the cascaded filter problem of the conventional loosly-coupled integration method and mitigates the computational burden of the conventional tightly-coupled integration method. An experiment result with field-collected measurements verifies the feasibility of the proposed method.

• 한국분무공학회지
• /
• 제18권3호
• /
• pp.132-139
• /
• 2013

Smoke emissions from light duty diesel vehicles were measured using light extinction method with the free acceleration test mode. The smoke emissions for each measurement cycle of the free acceleration method showed large variations according to driver's pedal pushing pattern. The smoke values for each measurement cycle initially increased and reach a peak value. Integration of the smoke emissions with time for each measurement cycle was performed to get a representative smoke value which was obtained by averaging the integrated results. Two kinds of integration time range were used. One is range over the whole measurement cycle of the free acceleration method. The other is only the acceleration range in the measurement cycle. Overall, variation of the representative smoke values obtained by the integration method was reduced comparing to the traditional representative smoke value which was obtained from a peak smoke value over the measurement cycle. Ten vehicles of the same model with 2.5 liter diesel engines, and seven vehicles of the same model with 2.7 liter diesel engines, were tested using the free acceleration test method.

• Earthquakes and Structures
• /
• 제8권6호
• /
• pp.1325-1348
• /
• 2015

Real-time hybrid testing (RTHT) involves virtual splitting of the structure into two parts: physical substructure that contains the key region of interest which is tested in a laboratory and numerical substructure that contains the remaining part of the structure in the form of a numerical model. This paper numerically assesses four step-by-step integration methods (Central difference method (CDM), Operator splitting method (OSM), Rosenbrock based method (RBM) and CR-integration method (CR)) which are widely used in RTHT. The methods have been assessed in terms of stability and accuracy for various realistic damping ratios of the physical substructure. The stability is assessed in terms of the spectral radii of the amplification matrix while the accuracy in terms of numerical damping and period distortion. In order to evaluate the performance of the methods, five carefully chosen examples have been studied - undamped SDOF, damped SDOF, instantaneous softening, instantaneous hardening and hysteretic system. The performance of the methods is measured in terms of a non-dimensional error index for displacement and velocity. Based on the error indices, it is observed that OSM and RBM are robust and performs fairly well in all the cases. CDM performed well for undamped SDOF system. CR method can be used for the system showing softening behaviour. The error indices indicate that accuracy of OSM is more than other method in case of hysteretic system. The accuracy of the results obtained through time integration methods for different damping ratios of the physical substructure is addressed in the present study. In the presence of a number of integration methods, it is preferable to have criteria for the selection of the time integration scheme. As such criteria are not available presently, this paper attempts to fill this gap by numerically assessing the four commonly used step-by-step methods.

• Journal of Advanced Marine Engineering and Technology
• /
• 제34권7호
• /
• pp.943-950
• /
• 2010

An efficient meshfree method based on a stabilized conforming nodal integration method is developed for elastoplastic contact analysis of metal forming processes. In this approach, strain smoothing stabilization is introduced to eliminate spatial instability in Galerkin meshfree methods when the weak form is integrated by a nodal integration. The gradient matrix associated with strain smoothing satisfies the integration constraint for linear exactness in the Galerkin approximation. Strain smoothing formulation and numerical procedures for path-dependent problems are introduced. Applications of metal forming analysis are presented, from which the computational efficiency has been improved significantly without loss of accuracy.

• Structural Engineering and Mechanics
• /
• 제4권6호
• /
• pp.589-600
• /
• 1996

An explicit 4th order time integration scheme for solving the convection-diffusion equation is discussed in this paper. A system of ordinary differential equations are derived first by discretizing the spatial derivatives of the relevant PDE using the finite difference method. The integration of the ODEs is then carried out using a 4th order scheme and a self-adaptive technique based on the spatial grid spacing. For a non-uniform spatial grid, different time step sizes are used for the integration of the ODEs defined at different spatial points, which improves the computational efficiency significantly. A numerical example is also discussed in the paper to demonstrate the implementation and effectiveness of the method.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권8호
• /
• pp.225-231
• /
• 2020

The paper aims to investigate the impact of trade integration on business cycle synchronization for the East Asian countries during 2005- 2017 based on the endogeneity hypothesis of Optimum Currency Area criteria. We test the determinants of business cycles by calculating bilateral trade, financial integration, and business cycle synchronization. Applying the system Generalized Method of Moments for dynamic panel data models, the results show that business cycle synchronization is highly associated with trade and financial integration. These findings confirm the endogeneity hypothesis that more trade integration will mitigate asymmetric shocks, and have a positive impact on the business cycle synchronization. The increased trade intensity and financial linkage lead to more correlated business cycles in East Asia. Apart from trade and financial integration, the trade structure differential, monetary policy similarity also influence the business cycle comovement. The significantly negative impact of trade structure differential on business cycle synchronization suggests that countries with less similar structures are more likely to undergo asymmetric shocks. The results also indicate that monetary policy matters for output comovement. This study recommends that the East Asian countries should focus on bilateral trade as well as financial integration with each other to reap benefits from the integration process.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
• /
• pp.517-518
• /
• 2006

Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography with a novel integration method. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and unsteady. The speckle movements which have been formed by a ground glass between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. A novel integration method has been developed to obtain projection data from the deflection angles for the speckle tomography.'The three-dimensional density fields have been reconstructed from the accurate projection values by a real-time multiplicative algebraic reconstruction technique (MART) with the developed integration method.