Volume 3 No. 1

January 2000
Pre-Calculus and Two Mid-Nineteenth Century American Novels

Pre-Calculus and Two Mid-Nineteenth Century American Novels

pp 45-56 (Vol 3 No 1 2000)

Jose Nilo G. Binongo 1
Department of Mathematics
Collegiate School
North Mooreland Road, Richmond, Virginia, U.S.A.

Marcus Wilfrid Alison Smith 2
School of Information and Software Engineering
University of Ulster
Newtownabbey, Co. Antrim, BT37 OQB, U.K.

ABSTRACT

Examples of practical applications in pre-calculus textbooks are taken mainly from physics, surveying and other branches of engineering. Students with a leaning mo,re towards the humanities than to the sciences can therefore be discouraged, and consequently in many high schools pre-calculus is not compulsory. In this paper we show that some pre-calculus topics can be relevant to the study of literary texts. In particular, we demonstrate how projections of vectors related to the frequency of occurrence of two prepositions can distinguish between two mid-nineteenth century American novels. This paper illustrates that it is possible to find unusual and intriguing examples to enliven courses and to impress on disinterested students that mathematics can impinge on unexpected territory.

Isolated Word Recognition Using Self­ Organizing Feature Map

Isolated Word Recognition Using Self­ Organizing Feature Map

pp 36-43 (Vol 3 No. 1 2000)

Lyne R. Palomar and Elmer P. D.adios
De La Salle University-Manila
2401 Taft Avenue, 1004 Manila, Philippines

Toshio Fukuda
Nagoya University
Furucho, Chikusa-ku, Nagoya City, 4648601 Japan

ABSTRACT

The problem of recognizing an isolated word using the Kohonen ‘s self-organizing feature map (SOFM) is pre­sented in this paper. Five words (LEFT, RIGHT, UP, DOWN and STOP) and recorded from 4 different speakers. For each speaker, 100 recordings of each word are taken and a total of 200 speech files serve as the input database to the recognition system. 100 speech files from this database are used as the training set while the other 100 are used as the testing set. Each speech file is then represented by 20 frames and the 11 LPC­Cepstrum (Linear Predictive Coding) coefficients are computed for each frame. This then serves as the input to the SOFM. The size of the SOFM, neighborhood function, the learning rate and the number of epochs are the parameters made to vary in the experimentation. It was observed that good recognition rates are achieved at bigger size maps with a bigger number of epochs.

Modeling and Controller Design of a DC motor

Modeling and Controller Design of a DC motor

pp 27-35 (Vol 3 No. 1 2000)

Alvin Chua 1 and Edwin Sybingco 2
1 Mechanical Engineering Department
2 Electronics & Communication Engineering Deparment De La Salle University-Manila
2401 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

This paper deals with the development of a procedure in modeling a DC motor and controller design. In the modeling process, the DC motor was modeled based on the work of Ogata. While the velocity controller was designed using a PI and PID. Graphs were generated to show the bounds of the coefficients that would avoid oscillations or overshoot. Analysis of the Kp, K1 and KD relationships shows its significance towards the proper choice of coefficients. The effectiveness of the procedure was verified through simulation and experimentation.

Partial Tin (Sn) Substitution of Strontium (Sr) in the 2212 BSCCO System

Partial Tin (Sn) Substitution of Strontium (Sr) in the 2212 BSCCO System

pp 21-26 (Vol 3 No 1 2000)

Jonathan S. Guevarra, Daniel P. Garcia, Amanda Valiente, Alex V. Quema, and Reuben Quiroga
Solid-Physics Laboratory, Physics Department, College of Science
De La Salle University-Manila
2401 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

The effects of doping Tin (Sn) into the Strontium (Sr) site of the 2212 Bi-Sr-Ca-Cu-O system via the modified solid-state method has been studied. X-ray diffraction analysis revealed a pure 2212 phase for the sample with nominal composition Bi2_0Srl.8Sn0_2Ca 1_0Cu2_0O 8 sintered in air at 860° C. for 24 hours and annealed in air at 855°C for 48 hours. Magnetic susceptibility and electrical resistivity easurements of this sample showed a Tex (onset) of 94°C and Tep (zero) of 95°C, respectively.

Synthesis of Tetra-O-Acetyl-J3-D­ Glucopyranoside-Modified 1,3- Dithiole-2-Thione

Synthesis of Tetra-O-Acetyl-J3-D­ Glucopyranoside-Modified 1,3- Dithiole-2-Thione

pp 15-20 (Vol 3 No 1 200)

Gerardo C. Janairo, Glenn V. Alea, Philip Reginald C. Alto, and Emmanuel V. Garcia
Chemistry Department, De La Salle University-Manila
2401 Taft Ave., Manila 1004 Philippines

ABSTRACT

Novel 4, 5-bis(2 ‘,3 ‘, 4 ‘, 6’-tetra-O-acetyl-/3-D-glucopyranosylthio)-l,3-dithiole-2-thione has been successfully synthesized in 21. 02% yield. The procedure for the preparation of this compound and its characterization will be described.

Tissue Culture of Nodal Segments from Nerium oleander L.

Tissue Culture of Nodal Segments from Nerium oleander L.

pp 9-14 (Vol 3 No 1 2000)

Minda P. Follosco
Biology Department, De La Salle University
2401 Taft Avenue, 1004 Manila, Philippines

ABSTRACT

A method for the micropropagation of Nerium oleander L. (Apocynaceae) from nodal segments was developed. Proliferating microshoot cultures were obtained by placing nodal segments on full-strength Murashige and Skoog (MS) medium supplemented with 40.00 µMBA alone; or a combination of 40.00 µM BA and low (0. 75 µM) and high (5.00 µM) concentrations of either NAA or 2,4-D. Profuse branching of the original nodal segments after subculturing was noted in treatments with low doses of either NAA or 2,4-D and MS with 40.00 µMBA. Callus formation at the base of node segments rather than shooting was favored by high concentration of either NAA or 2,4-D.

GABA and the Acid Resistance of the Filamentous Fungus Bispora sp.

GABA and the Acid Resistance of the Filamentous Fungus Bispora sp.

pp 1-8 (Vol 3 No. 1 2000)

Hartmut Gimmler
Julius-van Sachs-Institute of Bioscience, University of Wurzburg,
Julius-van Sachs-Platz 2, 0-97082 Wurzburg, Germany

ABSTRACT

This is a study of the uptake and metabolism of y­am inobutyric acid (GABA) by the acid resistant filamentous fungus Bispora sp. as well as the influence of the external pH on the amino acid composition of the fungus. External GABA can replace NH 4+ as nitrogen source and glycerol as carbon source. This demonstrates that GABA is readily taken up into the cells (in spite of its cationic form at pH I.OJ and subsequently metabolised inside the cells. The effects of GABA on the amino acid composition are in agreement with the view that GABA ranks together with glutamate, arginine, glutamine and lysine as key amino acid of Bispora sp. and that there is a close relationship between GABA and glutamate: Both pools are interconnected by a decarboxylation reaction and a transamination reaction, with GABA being a storage poor for glutamate. Acid pH of the medium and excess of NH4 + and glutamate favour the decarboxylation of glutamate causing an increase of both the internal GABA pool and the GABA to glutamate ratio. Nitrogen deficiency and/or high rates of amino acid synthesis starting from glutamate (low glutamate level) stimulates conversion from the GABA reservoir via transamination to glutamate.