Manila Journal of Science 10 (2017), pp. 1-15

Oscillation Propagation in a Two-Dimensional Lattice of Mutually Repressive Nodes

Abstract

Concurrent decision-making networks represent decision systems where the utility of a component (node) becomes dominant by repressing other nodes. These networks are commonly used in modeling competitive interactions in the computational, biological, and social sciences. Most of the existing studies about concurrent decision-making focus on equilibrium convergence of the utilities. However, there are many cases where oscillations can arise. Here, we consider concurrent decision-making networks that follow a two-dimensional lattice topology where one node is a source of oscillations. Read More

Arboleda

Density Functional Theory–Based Study of the Structural Properties of Hexagonal Boron Nitride/Graphene Hetero-Bilayer and Silicene/Hexagonal Boron Nitride/Graphene Hetero-Structures for Thin Film Transistor Applications

Abstract

The geometric properties and structural stability of hexagonal boron nitride on graphene (h-BN/G) hetero-bilayer and silicene on hexagonal boron nitride on graphene (Si/h-BN/G) hetero-structure were investigated using density functional theory. The calculations were performed through the Vienna Ab Initio Simulation package (VASP) implemented with three different approximations, namely, the local density approximation (LDA), general gradient approximation (GGA), and GGA with Tkatchenko–Scheffler van der Waals (vdW) correction. In reference to the experimental interlayer distance and binding energy between graphitic layers, the h-BN/G hetero-bilayer and Si/h-BN/G hetero-structures were stable. Read More

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Comparative Analysis on Lettuce Quality Produced From Urban Agriculture and Organic Farming

Abstract

A previous project has proven that urban agriculture is feasible and more environment friendly than traditional agriculture. The question if the yield of urban agriculture through hydroponics is comparable to organic farming or not arose. Evidence gathered showing comparability should provide added value to the products of urban agriculture. This can in turn make the practice of urban agriculture not only more profitable but also more attractive. A hydroponics setup was placed in the rooftop of St. Joseph Hall of De La Salle University in Manila. The organic farming setup was placed in the grounds of De La Salle University in Dasmariñas City, Cavite. Read More

Uy Cover

Survey on the Current Status of Serial and Parallel Algorithms of Frequent Itemset Mining

Abstract

Frequent itemset mining is one of the fundamental but time-demanding tasks in data mining. It is used to find frequent patterns and generate association rules for these patterns. With the availability of inexpensive storage and progress in data capture technology, the availability of data has reached exa-scale already. But improvements in processor and network technology open up opportunity for parallel and distributed computing to be applied in frequent itemset mining to improve its performance in the light of the challenge of “big data”. Thus, there are challenges in frequency itemset mining to fully harness the parallel processing capability of the computer hardware technologies. Read More

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On the pH and Acid Neutralizing Capacity Profile of Manila Bay Coastal Water Samples in Manila, Philippines

Abstract

For any body of water, its pH and acid neutralizing capacity (ANC) are two important determinants of its overall condition. The ANC has to be high enough to maintain the pH at an optimal level in order to resist acidification and thereby sustain marine life. An assessment of the pH and ANC of Manila Bay coastal waters along Manila and Pasay, Philippines, was done using 16 collected coastal water samples from four different and equally divided geographic sectors along Roxas Boulevard. The pH of the samples was measured using a pH meter while the ANCs were determined via potentiometric titration against sulfuric acid (H2SO4). Read More

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Fish Species Abundance and Species Richness in a Diverted Channel in Ilog, Negros Occidental, Philippines

Abstract

The effect of channel diversion in Ilog, Negros Occidental, was studied by comparing fish species abundance and species richness in the two river mouths, namely, Bungol Channel in Andulauan and Bocana in Lower Ilog River of the Ilog-Hilabangan River System. Data were collected for six months, from March to May 2011 for the dry season and from July to September 2011 for the wet season. Samples were collected using cast net and other indigenous gears in the locality. About 56 fish species belonging to 49 families were noted, and only three of these were introduced species. Fish species abundance was significantly different (t-test, p = 0.04), only in Bocana during the dry season. Nevertheless, fish species richness varied with season, as evidenced by the higher values observed in different river mouths. Tidal flow can significantly contribute to fish abundance and species richness, particularly during the dry season.  Read More

Educational Vulnerability Assessment of Youth on Natural Disasters: The Case of Brgy. Paciano Rizal, Bay, Laguna

Educational Vulnerability Assessment of Youth on Natural Disasters: The Case of Brgy. Paciano Rizal, Bay, Laguna

Abstract

This study assessed the educational vulnerability of youths in Brgy. Paciano Rizal, Bay, Laguna, by determining their perceived level of awareness on natural disasters and disaster management. Seventy youth respondents aged 13 to 19 years old were randomly selected using stratified random sampling. The data were gathered through the personal interview method. The data were analyzed using descriptive statistics and thematic analysis and with reference to Maskrey’s concept of educational vulnerability. Results of the study describe that the youth in Brgy. Paciano Rizal perceived themselves to have a high level of awareness of natural disasters and disaster management.  Read More

On the Construction of Some LCD Codes over Finite Fields

On the Construction of Some LCD Codes over Finite Fields

Abstract

Linear codes with complementary duals (LCD codes) are linear codes that intersect with their duals trivially. In this paper, we construct some families of LCD codes using Massey’s characterization of an LCD code. In particular, we obtain some classes of binary LCD codes using the permutation matrix and the all-one matrix. We also explicitly construct generator matrices of LCD codes using the generator matrices of self-dual codes and binary Hamming codes. For, 3 r 7 the binary LCD codes obtained using the Hamming matrix Hr are optimal.  We also consider some known methods of combining two or more codes such as the direct product, direct sum, and Plotkin sum. We show that the direct product and the direct sum of two LCD codes are also LCD. We also prove that the permutation equivalence of codes preserves the LCD-ness of linear codes. Read More

Chang Flores

Tegumental Studies of Adult Fasciola gigantica (Giant liver fluke) from Philippine Carabaos (Bubalus bubalis) Using Scanning Electron Microscopy for Lead Bio-Indicator Analysis

Abstract

Recent studies show that parasites such as liver flukes have a capacity to bioaccumulate heavy metals significantly than the liver and muscle tissues of the host without compromising effects on them. One such heavy metal is lead (Pb) which is an abundant pollutant in the environment.Therefore, this study aimed to evaluate the effects of lead in the tegument of Fasciola gigantica (giant liver fluke) isolated from infected livers of carabaos in vitro using the following concentrations of lead: 0ppm, 110ppm, 160ppm, and 210ppm. Read More