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296 MULTI-VERSION AND EVOLUTION SUPPORT FOR MULTIDIMENSIONAL DATABASE SCHEMA Jarernsri L. Mitrpanont and Somchart Fugkeaw (NO. 773) Department of Computer Science, Faculty of Science, Mahidol University ccjlm@mahidol.ac.th, somchartf@yahoo.com Key words : Multidimensional schema, Schema Evolution, Schema Versioning Technique, Multi-Schema Version This paper proposes an evolution approach for multidimensional database (MDB) schemata based on objectedoriented and schema versioning technique. A schema evolution framework and two versioning algorithms, namely, Forward Schema Versioning algorithm and Backward Schema Versioning Algorithm are proposed to support the MDB schema changes and schema version control respectively. Our approach satisfies the full scale support in both forward schema evolution and backward schema versioning. Finally, the prototype system called SEMAN (Schema Evolution MANager) is developed to handle the MDB schema modification as well as to control the multi-schema versions based on our proposed model. (Proceedings of the 23 rd IASTED International Multi-Conference on Databases and Applications, pp. 151-156, February 14-16, 2005, Innsbruck, Austria.) CHARACTERIZATION OF SAMADHI STATE DURING MEDITATION BY HEART RATE VARIABILITY ANALYSIS (NO. 774) Sukanya Phongsuphap 1 , Yongyuth Phongsuphap 2 , Pakorn Chantanamasta 3 , Chidchanok Lursinsap 4 1 Department of Computer Science, Faculty of Science, Mahidol University ccsps@mahidol.ac.th ; 2 Health Care Reform Project, National Health Security Office ; 3 Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University; 4 Department of Mathematics, Faculty of Science, Chulalongkorn University, Key words: Biosignal Processing, Heart Rate Variability, Meditation The main objective of this work is to investigate the heart rate variability spectral parameters including the very-low frequency power (VLF), the low frequency power (LF), and the high frequency power (HF) for determining the Samadhi state during meditation. The experiment was performed on 5 subjects in the experimental group and 20 subjects in the control group. During 5-month period of data collection, we obtained 133 and 117 segments of RR-interval data in the Samadhi state and the normal state respectively. Results showed that a combination of VLF, LF, and HF had a high capability for discriminating the Samadhi state and the non-Samadhi state. We obtained an accuracy of 96.8% by Fisher discriminant function analysis. The characteristic patterns of the Samadhi state are as follows. The VLF was very low, while the HF was higher than normal. The LF was remarkably high. In particular, a norrowed band with high amplitude peak around the frequency 0.1 Hz appeared. In contrast, during ordinarily quiet sitting, the VLF was very high, while the HF was low, and the LF was relatively lower than the Samadhi state. The results indicated that Samadhi state might have the following health benefits: resetting baroreflex sensitivity and increasing parasympathetic tone. (Proceeding of the fifth International Workshop on biosignal Interpretation, pp. 139-142, September 6-8, 2005, Tokyo, JAPAN. The Thailand Research Fund (MRG4780135) PERFORMANCE STUDY AND DEVELOPMENT STRATEGIES ON THE SENDER-INITIATED MULTICAST (NO. 775) Visoottiviseth Vasaka 1 , Kido Hiroyuki 2 , Iida Katsuyoshi 2 , Kadobayashi Youki 2 , and Yamaguchi Suguru 2 1 Computer Science Department, Mahidol University, Thailand E-mail : ccvvs@mahidol.ac.th ; 2 Graduate School of Information Science, Nara Institute of Science and Technology, Japan E-mail: {hiro-kid, katsu, youki-k, suguru}@is.naist.jp Key words : Routing, Multicast, Small Group Communication, Forwarding States Reduction Although IP Multicast offers efficient data delivery for large group communications, the most critical issue delaying widespread deployment of IP Multicast is the scalability of multicast forwarding state as the number of multicast groups increases. Sender-Initiated Multicast (SIM) was proposed as an alternative multicast forwarding scheme for small group communications with incremental deployment capability. The key feature of SIM is in its Preset mode with the automatic SIM tunneling function, which maintaining forwarding information states only on the branching routers. To demonstrate how SIM increases scalability with respect to the number of groups, in this paper we evaluate the proposed protocol both through simulations and real experiments. As from the network operator’s point of view, the bandwidth consumption, memory requirements on state-and-signaling per session in routers, and the processing overhead are considered as evaluation parameters. Finally, we investigated the strategies for incremental deployment. (The Institute of Electronics, Information and Communication Engineers (IEICE) Transactions on Communication, VOL.E88-B, No.4, Special Section on Internet Technology V, pp. 1395-1402, April 2005.) A DELAY-DIFFERENTIAL EQUATION MODEL OF THE FEEDBACK-CONTROLLED HYPOTHA- LAMUS-PITUITARY-ADRENAL AXIS IN HUMANS Lenbury Y., Pornsaward P. Faculty of Science (NO. 776) Department of Mathematics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand. E-mail scylb@mahidol.ac.th., ppornsup@hotmail.com Key words : cortisol secretion, delay-feedback controlled system, Hopf bifurcation, nonlinear model The present work develops and analyses a model system of delay-differential equations which describes the core dynamics of the stress-responsive hypothalamus-pituitary-adrenal axis. This PDF created with FinePrint pdfFactory Pro trial version http://www.pdffactory.com
Mahidol University Annual Research Abstracts, Vol. 33 297 neuroendocrine ensemble exhibits prominent pulsatile secretory patterns governed by nonlinear and time-delayed feedforward and feedback signal interchanges. Formulation and subsequent bifurcation analysis of the model provide a qualitative and mathematical frame work for a better understanding of the delayed responsive mechanisms as well as the dynamic variations in different pathological situations. (Mathematical Medicine and Biology, 22(1)(2005) 15-33.) MATHEMATICAL MODELS FOR PRESSURE CONTROLLED VENTILATION OF OLEIC ACID- INJURED PIGS (NO. 777) Crooke P.S. 1 , Kongkul K. 2 , Lenbury Y. 2 , Adams A.B. 3 , Carter C.S. 3 , Marini J.J. 3 , Hotchkiss J.R. 3 1 Department of Mathematics, Vanderbilt University, Nashville, TN 37240, USA. E-mail : pscrooke@math.vanderbilt.edu; 2 Department of Mathematics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand. E-mail : konvika@tsu.ac.th, scylb@mahidol.ac.th; 3 Pulmonary and Critical Care Medicine, Regions Hospital and University of Minnesota, St. Paul MN 55101 USA. E-mail : hotchkissjr@upmc.edu Key words : oleic acid injury, mathematical model, variable compliance One-compartment, mathematical models for pressure controlled ventilation, incorporating volume dependent compliances, linear and nonlinear resistances, are constructed and compared with data obtained from healthy and (oleic acid) lunginjured pigs. Experimental data are used to find parameters in the mathematical models and were collected in two forms. Firstly, the Pe-V curves for healthy and lung injured pigs were constructed; these dta are used to compute compliance functions for each animal. Secondly, dynamic data from pressure controlled ventilation for a variety of applied pressures are used to estimate resistance parameters in the models. The models were then compared against the collected dynamic data. The best mathematical models are ones with compliance functions of the form C(V) = a + bV where a and b are constants obtained from the Pe-V curves and the resistive pressures during inspiration change from a linear relation Pr = RQ to nonlinear relation Pr = RQ where Q is the flow into the one-compartment lung and is a positive number. The form of the resistance terms in the mathematical models indicate the possible presence of gas-liquid foams in the experimental data. (Mathematical Medicine and Biology 22 (2005) 99-112) DELAY EFFECT IN MODELS OF POPULATION GROWTH (NO. 778) Giang D.V. 1 , Lenbury Y. 2 , Seidman T.I. 3 1 Hanoi Insititue of Mathematics, 18 Hoang Quoc Viet, 10307 Hanoi, Vietnam, E-mai dvgiang@math.ac.vn ; 2 Department of Mathematics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand. E-mail : scylb@mahidol.ac.th; 3 Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, MD 21250 USA. E-mail Seidman@math.umbc.edu Key words : Delay differential equations, Comparison theorem Oneparameter semi-group Frist we systematize earlier results on the global stability of the model x + μx = f(x(‘ – τ)) of population growth. Second, we investigate the effect of delay on the asymptotic behavior when the nonlinearity f is a unimodal function. Our results can be applied to several population models [Elements of Mathematical Ecology, 2001 [7]; Appl. Anal. 43 (1992) 109-124; Math. Comput. Modelling, in press; Funkt. Boil. Med. 256 (1982) 156-164; Math. Comput. Modelling 35 (2002) 719-731; Mat. Stos. 6 (1976) 25-40] because the function f does not need to be monotone or differentiable. Specifically, our results generalize earlier result of [Delay Differential Equations with Applications in Population Dynamics 1993], since our function f may not be differentiable. (Journal of Mathematical Analysis and Applications 305 (2005) 631-643.) THREE-DIMENSION MAGNETOTELLURIC INVASION : DATA SPACE METHOD (NO. 779) Siripunvaraporn W. 1 , Egbert G. 2 , Lenbury Y. 3 , Uyeshima M. 4 1 Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400, Thailand. E-mail : scwsp@mahidol.ac.th; 2 College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis OR 97331, USA; 3 Department of Mathematics Faculty of Science, Mahidol University, Bangkok 10400, Thailand. E-mail scylb@mahidol.ac.th; 4 Earthquake Research Insitute, University of Tokyo, 1-1-1 Yayoi, Bunkyoku, Tokyo 113-0032, Japan. Key words : Magnetotellurics, Data-space method, 3D inversion, Occam’s inversion A three-dimensional magnetotelluric (MT) minimum structure inversion algorithm has been developed based on a dataspace variant of the Occam approach. Computational costs associated with construction and inversion of model-space matrices make a model-space Occam approach to 3D MT inversion impractical. These difficulties are overcome with a data-space approach,where matrix dimensions depend on the size of the data set, rather than the number of model parameters. With the transformation to data space it becomes feasible to invert modest 3D MT data sets on a PC. To reduce computational time, a relaxed convergence criterion is used for the iterative forward modeling code used to compute the sensitivity matrix. This allows reduction in computational time by more than 70% without affecting the inversion results. Numerical experiments with synthetic data show that reasonable fits can be obtained within a small number of iterations, with a few additional iterations required to eliminate unnecessary structure and find the model with minimum norm. (Physics of the Earth and Planetary Interiors. 150 (2005) 3-14.) PDF created with FinePrint pdfFactory Pro trial version http://www.pdffactory.com
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