• The Journal of Asian Finance, Economics and Business
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• 제8권2호
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• pp.1025-1032
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• 2021

The study investigates factors affecting the loyalty of Food Delivery Application (FDA) service in Thailand. This study employs quantitative research methodology with a non-probability sampling method to draw 510 FDA samples from the FDA users in Thailand. The online questionnaires with a Cronbach's alpha coefficient of 0.886 were used as a research tool to collect data from samples. By using the Structural Equation Modeling (SEM) to analyze data, the results show that trustworthiness, social influence, system design, and task-technology fit affect the user's technology acceptance, which also show the significant relationship with the loyalty of FDA users in Thailand. The study checks the harmony with the statistics; χ2 = 258.686, df. =160, χ2/df. = 1.616, p-value = 0.050, CMIN/DF = 1.616, GFI = 0.960, AGFI = 0.969, TLI = 0.953, CFI = 0.965, RMSEA = 0.047, significant level at 0.05, along with testing the weight factor. In conclusion, the research model was harmonious with the empirical data at the significant level 0.05. The finding of this study suggested that the FDA service provider might apply this research finding to develop a greater understanding of the FDA's customer loyalty, as well as determine marketing strategies, identify opportunities, and create a competitive advantage in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.670-684
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• 2024

3D Cross-Modal Retrieval (3DCMR) is a task that retrieves 3D objects regardless of modalities, such as images, meshes, and point clouds. One of the most prominent methods used for 3DCMR is the Cross-Modal Center Loss Function (CLF) which applies the conventional center loss strategy for 3D cross-modal search and retrieval. Since CLF is based on center loss, the center features in CLF are also susceptible to subtle changes in hyperparameters and external inferences. For instance, performance degradation is observed when the batch size is too small. Furthermore, the Mean Squared Error (MSE) used in CLF is unable to adapt to changes in batch size and is vulnerable to data variations that occur during actual inference due to the use of simple Euclidean distance between multi-modal features. To address the problems that arise from small batch training, we propose a Noisy Center Loss (NCL) method to estimate the optimal center features. In addition, we apply the simple Siamese representation learning method (SimSiam) during optimal center feature estimation to compare projected features, making the proposed method robust to changes in batch size and variations in data. As a result, the proposed approach demonstrates improved performance in ModelNet40 dataset compared to the conventional methods.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.267-273
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• 2009

A representation for the Drazin inverse of an arbitrary square matrix in terms of the eigenprojection was established by Rothblum [SIAM J. Appl. Math., 31(1976) :646-648]. In this paper perturbation results based on the representation for the Darzin inverse $A^D\;=\;(A-X)^{-1}(I-X)$ are developed. Norm estimates of $\parallel(A+E)^D-A^D\parallel_2/\parallel A^D\parallel_2$ and $\parallel(A+E)^#-A^D\parallel_2/\parallel A^D\parallel_2$ are derived when IIEI12 is small.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 1995년도 정기학술강연회 발표논문 초록집
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• pp.122-128
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• 1995

전회의 연구(최와 고, 1994)에서 1／6$^{\circ}$ 경.위도 해상도를 갖는 동아시아 해역의 8개 분조의 조석체계를 수치 시뮬레이션으로 산정하였다. 본 연구에서는 DBDBS database의 5분 격자 해상 수심을 그대로 적용하는 5분 격자 체재의 Gulf of Siam(Thailand), 남중국해, 자바해(Java Sea)를 포함하는 모형을 수립하였다. 서측경계는 Malacca해협의 서측안이며 북측 경계는 대만 해협, 동측경계는 대만남측-루손섬북측, 만다나오남측과 Celebes(Sulawesi)의 북동단의 Manado, Celebes섬의 Makasar부근과 Flores섬의 북단을 연결하는 5개소의 개방 경계를 택하였다. (중략)

• Journal of applied mathematics & informatics
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• 제27권3_4호
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• pp.943-953
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• 2009

In this paper, we give the lower and upper bounds for inverse elements of strictly diagonally dominant seventh-diagonal matrices, and improve the bounds on [SIAM. J. matrix Anal.App1.20(1999)820-837].

• 한국콘텐츠학회논문지
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• 제20권7호
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• pp.212-222
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• 2020

본 연구의 목적은 전 세계 산업수학의 흐름을 주도하는 미국산업응용수학 학회에서 출판하는 논문들의 연구현황 및 동향을 거시적으로 파악하는 데 있다. 이를 위해 2016년부터 2019년까지 6,255편의 논문 제목 및 초록을 수집하였으며, LDA 기법을 활용한 토픽모델링과 시계열회귀모형 분석을 수행하였다. 분석 결과 첫째, 산업수학 분야는 해석학을 중심으로 기하학, 대수학, 위상수학, 이산수학, 확률 및 통계 등 다양한 분야에서 연구가 진행되었다. 둘째, 시간이 흐름에 따라 상승하는 연구 주제는 수리유체역학, 그래프이론, 확률미분방정식이었으며, 하강하는 연구 주제는 계산이론과 고전기하로 나타났다. 연구 결과는 산업수학 분야의 지적 구조에 대한 전체적인 흐름 및 변화에 대한 이해를 바탕으로 연구자들에게는 향후 연구 방향에 대해서, 그리고 교육 현장에는 시대 변화를 반영한 산업수학 교육과정을 수립하는데 시사점을 제공할 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.583-586
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• 2002

In this research, we propose a flexible conveying system (FCS) which consists of multiple arrays of cells. Each cell is a wheel driven by a two degree-of-freedom mechanism. The direction and velocity of cell are controlled based on the concept of hybrid control under a distributed network. Each cell has its own controller under a subsumption architecture for low-level control. A cell communicates with its four neighboring cells to manipulate n targeted object towards its desired position. The high-level control assigns a desired position and direction of the object to each cell. The path of each object is generated by many supporting cells. Moreover, the FCS can handle multiple objects simultaneously. To study the flexible conveying system, a GUI-based simulator of flexible conveying system is constructed. The simulated results show that the system can handle multiple objects independently and simultaneously under the proposed hybrid control architecture.

• 대한수학회논문집
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• 제20권3호
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• pp.563-578
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• 2005

In [Z. Cai and B. C. Shin, SIAM J. Numer. Anal. 40 (2002), 307-318], we developed the discrete first-order system least squares method for the second-order elliptic boundary value problem by directly approximating $H(div){\cap}H(curl)-type$ space based on the Helmholtz decomposition. Under general assumptions, error estimates were established in the $L^2\;and\;H^1$ norms for the vector and scalar variables, respectively. Such error estimates are optimal with respect to the required regularity of the solution. In this paper, we study solution methods for solving the system of linear equations arising from the discretization of variational formulation which possesses discrete biharmonic term and focus on numerical results including the performances of multigrid preconditioners and the finite element accuracy.

• 대한수학회지
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• 제50권4호
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• pp.695-713
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• 2013

We formulate and study a predator-prey model with non-monotonic functional response type and weak Allee effects on the prey, which extends the system studied by Ruan and Xiao in [Global analysis in a predator-prey system with nonmonotonic functional response, SIAM J. Appl. Math. 61 (2001), no. 4, 1445-1472] but containing an extra term describing weak Allee effects on the prey. We obtain the global dynamics of the model by combining the global qualitative and bifurcation analysis. Our bifurcation analysis of the model indicates that it exhibits numerous kinds of bifurcation phenomena, including the saddle-node bifurcation, the supercritical and the subcritical Hopf bifurcations, and the homoclinic bifurcation, as the values of parameters vary. In the generic case, the model has the bifurcation of cusp type of codimension 2 (i.e., Bogdanov-Takens bifurcation).

• Kyungpook Mathematical Journal
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• 제52권2호
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• pp.109-136
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• 2012

We aim at presenting certain unexpected functional relations among various hypergeometric functions of one or several variables (for example, see the identities in Corollary 5) by making use of Carlson's method employed in his work (Some extensions of Lardner's relations between $_0F_3$ and Bessel functions, SIAM J. Math. Anal. 1(2)(1970), 232-242).