157 research outputs found
Artificial Catalytic Reactions in 2D for Combinatorial Optimization
Presented in this paper is a derivation of a 2D catalytic reaction-based
model to solve combinatorial optimization problems (COPs). The simulated
catalytic reactions, a computational metaphor, occurs in an artificial chemical
reactor that finds near-optimal solutions to COPs. The artificial environment
is governed by catalytic reactions that can alter the structure of artificial
molecular elements. Altering the molecular structure means finding new
solutions to the COP. The molecular mass of the elements was considered as a
measure of goodness of fit of the solutions. Several data structures and
matrices were used to record the directions and locations of the molecules.
These provided the model the 2D topology. The Traveling Salesperson Problem
(TSP) was used as a working example. The performance of the model in finding a
solution for the TSP was compared to the performance of a topology-less model.
Experimental results show that the 2D model performs better than the
topology-less one.Comment: 8 pages, 2 figures, In H.N. Adorna (ed.) Proceedings of the 3rd
Symposium on Mathematical Aspects of Computer Science (SMACS 2006), Adventist
University of the Philippines, Silang, Cavite, Philippines, 19-20 October
2006 (Published by the Computing Society of the Philippines
A System for Sensing Human Sentiments to Augment a Model for Predicting Rare Lake Events
Fish kill events (FKE) in the caldera lake of Taal occur rarely (only 0.5\%
in the last 10 years) but each event has a long-term effect on the
environmental health of the lake ecosystem, as well as a devastating effect on
the financial and emotional aspects of the residents whose livelihood rely on
aquaculture farming. Predicting with high accuracy when within seven days and
where on the vast expanse of the lake will FKEs strike will be a very important
early warning tool for the lake's aquaculture industry. Mathematical models to
predict the occurrences of FKEs developed by several studies done in the past
use as predictors the physico-chemical characteristics of the lake water, as
well as the meteorological parameters above it. Some of the models, however,
did not provide acceptable predictive accuracy and enough early warning because
they were developed with unbalanced binary data set, i.e., characterized by
dense negative examples (no FKE) and highly sparse positive examples (with
FKE). Other models require setting up an expensive sensor network to measure
the water parameters not only at the surface but also at several depths.
Presented in this paper is a system for capturing, measuring, and visualizing
the contextual sentiment polarity (CSP) of dated and geolocated social media
microposts of residents within 10km radius of the Taal Volcano crater
(N, E). High frequency negative CSP co-occur with FKE for
two occasions making human expressions a viable non-physical sensors for
impending FKE to augment existing mathematical models.Comment: 20 pages, 7 figures, appeared in Proceedings of the Joint 12th
International Agricultural Engineering Conference and Exhibition, 65th PSAE
National Convention, and 26th Philippine Agricultural Engineering Week (PSAE
2015), KCC Convention and Events Center, General Santos City, Philippines,
19-25 April 201
A Framework for a Multiagent-based Scheduling of Parallel Jobs
This paper presents a multiagent approach as a paradigm for scheduling
parallel jobs in a parallel system. Scheduling parallel jobs is performed as a
means to balance the load of a system in order to improve the performance of a
parallel application. Parallel job scheduling is presented as a mapping between
two graphs: one represents the dependency of jobs and the other represents the
interconnection among processors. The usual implementation of parallel job
scheduling algorithms is via the master-slave paradigm. The master-slave
paradigm has inherent communication bottleneck that reduces the performance of
the system when more processors are needed to process the jobs. The multiagent
approach attempts to distribute the communication latency among the processors
which improves the performance of the system as the number of participating
processors increases. Presented in this paper is a framework for the behavior
of an autonomous agent that cooperates with other agents to achieve a community
goal of minimizing the processing time. Achieving this goal means an agent must
truthfully share information with other agents via {\em normalization}, {\em
task sharing}, and {\em result sharing} procedures. The agents consider a
parallel scientific application as a finite-horizon game where truthful
information sharing results into performance improvement for the parallel
application. The performance of the multiagent-based algorithm is compared to
that of an existing one via a simulation of the wavepacket dynamics using the
quantum trajectory method (QTM) as a test application. The average parallel
cost of running the QTM using the multiagent-based system is lower at higher
number of processors.Comment: 8 pages, 8 figures, in R.P. Salda\~na (ed.) Proceedings of the 6th
Philippine Computing Science Congress (PCSC 2006), Ateneo De Manila
University, Loyola Heights, Quezon City, Philippines, 28-29 March 2006, pp.
81-88 (CDROM ISSN 1908-1146
Synchronization of ad hoc Clock Networks
We introduce a graph-theoretic approach to synchronizing clocks in an {\em ad
hoc} network of ~timepieces. Clocks naturally drift away from being
synchronized because of many physical factors. The manual way of clock
synchronization suffers from an inherrent propagation of the so called "clock
drift" due to "word-of-mouth effect." The current standard way of automated
clock synchronization is either via radio band transmission of the global clock
or via the software-based Network Time Protocol (NTP). Synchronization via
radio band transmission suffers from the wave transmission delay, while the
client-server-based NTP does not scale to increased number of clients as well
as to unforeseen server overload conditions (e.g., flash crowd and time-of-day
effects). Further, the trivial running time of NTP for synchronizing an
-node network, where each node is a clock and the NTP server follows a
single-port communication model, is~\bigO(N). We introduce in this paper a
\bigO(\log N) time for synchronizing the clocks in exchange for an increase
of \bigO(N) in space complexity, though through creative "tweaking," we later
reduced the space requirement to~\bigO(1). Our graph-theoretic protocol
assumes that the network is \K_N, while the subset of clocks are in an
embedded circulant graph \C_{n with ~jumps and clock information is
communicated through circular shifts within the \C_{n. All ~nodes
communicate via a single-port duplex channel model. Theoretically, this
synchronization protocol allows for more synchronizations
than the client-server-based one. Empirically through statistically replicated
multi-agent-based microsimulation runs, our protocol allows at most 80\% of the
clocks synchronized compared to the current protocol which only allows up to
30\% after some steady-state time.Comment: 11 pages, 9 figures, appeared in H.N. Adorna and A.A. Sioson (eds.)
Proceedings of the 7th National Symposium on Mathematical Aspects of Computer
Science (SMACS 2014), Ateneo de Naga University, Naga City, Philippines,
24-28 November 2014, pp. 33-43. Paper submitted to Philippine Computing
Journal (ISSN 1908-1995
Inferences in a Virtual Community: Demography, User Preferences, and Network Topology
This paper presents a computational procedure for extracting demography data,
mining patterns of human preferences, and measuring the topology of a virtual
network. The network was created from the personal and relationships data of an
online Internet-based community, where persons are considered nodes in the
network, and relationships between persons are considered edges. A community of
Friendster users whose listed hometown is Los Ba\~nos, Laguna was used as a
test bed for the methodology. The method was able to provide the following
demographic, preferential, and topological results about the test bed: (1)
There are more female users (52.34\%) than male (47.66\%); (2) Homophily (i.e.,
birds-of-a-feather adage) is observed in the preferences of users with respect
to age levels, such that they are strongly biased towards being friends with
users of a similar age; (3) There is heterophily in gender preference such that
friendship among users of the opposite gender occurs more often. (4) It
exhibits a small-world characteristic with an average path length of 4.5
(maximum=12) among connected users, shorter than the well-known {\em six
degrees of separation}~\cite{travers69}; And (5) The network exhibits a
scale-free characteristics with heavily-tailed power-law distribution (with the
power and ) suggesting the presence of many users
acting as the network hubs. The methodology was successful in providing
important data from a virtual community which can be used by several
researchers in the fields of statistics, mathematics, physics, social sciences,
and computer science.Comment: 12 pages, 8 figures, appeared in Proceedings (CDROM) of the 6th
National Conference on IT Education (NCITE 2008), University of the
Philippines Los Ba\~nos, College, Laguna, Philippines, 23-24 October 200
On Gobbledygook and Mood of the Philippine Senate: An Exploratory Study on the Readability and Sentiment of Selected Philippine Senators' Microposts
This paper presents the findings of a readability assessment and sentiment
analysis of selected six Philippine senators' microposts over the popular
Twitter microblog. Using the Simple Measure of Gobbledygook (SMOG), tweets of
Senators Cayetano, Defensor-Santiago, Pangilinan, Marcos, Guingona, and
Escudero were assessed. A sentiment analysis was also done to determine the
polarity of the senators' respective microposts. Results showed that on the
average, the six senators are tweeting at an eight to ten SMOG level. This
means that, at least a sixth grader will be able to understand the senators'
tweets. Moreover, their tweets are mostly neutral and their sentiments vary in
unison at some period of time. This could mean that a senator's tweet sentiment
is affected by specific Philippine-based events.Comment: 13 pages, 6 figures, submitted to the Asia Pacific Journal on
Education, Arts, and Science
Information Spread Over an Internet-mediated Social Network: Phases, Speed, Width, and Effects of Promotion
In this study, we looked at the effect of promotion in the speed and width of
spread of information on the Internet by tracking the diffusion of news
articles over a social network. Speed of spread means the number of readers
that the news has reached in a given time, while width of spread means how far
the story has travelled from the news originator within the social network.
After analyzing six stories in a 30-hour time span, we found out that the
lifetime of a story's popularity among the members of the social network has
three phases: Expansion, Front-page, and Saturation. Expansion phase starts
when a story is published and the article spreads from a source node to nodes
within a connected component of the social network. Front-page phase happens
when a news aggregator promotes the story in its front page resulting to the
story's faster rate of spread among the connected nodes while at the same time
spreading the article to nodes outside the original connected component of the
social network. Saturation phase is when the story ages and its rate of spread
within the social network slows down, suggesting popularity saturation among
the nodes. Within these three phases, we observed minimal changes on the width
of information spread as suggested by relatively low increase of the width of
the spread's diameter within the social network. We see that this paper
provides the various stakeholders a first-hand empirical data for modeling,
designing, and improving the current web-based services, specifically the IT
educators for designing and improving academic curricula, and for improving the
current web-enabled deployment of knowledge and online evaluation of skills.Comment: 11 pages, 9 figures, initially appeared in Proceedings (CDROM) of the
8th National Conference on Information Technology Education, La Carmela de
Boracay Convention Center, Boracay Island, Malay, Aklan, Philippines, 20-23
October 201
The Interactive Effects of Operators and Parameters to GA Performance Under Different Problem Sizes
The complex effect of genetic algorithm's (GA) operators and parameters to
its performance has been studied extensively by researchers in the past but
none studied their interactive effects while the GA is under different problem
sizes. In this paper, We present the use of experimental model (1)~to
investigate whether the genetic operators and their parameters interact to
affect the offline performance of GA, (2)~to find what combination of genetic
operators and parameter settings will provide the optimum performance for GA,
and (3)~to investigate whether these operator-parameter combination is
dependent on the problem size. We designed a GA to optimize a family of
traveling salesman problems (TSP), with their optimal solutions known for
convenient benchmarking. Our GA was set to use different algorithms in
simulating selection (), different algorithms () and
parameters () in simulating crossover, and different parameters () in
simulating mutation. We used several -city TSPs () to represent the different problem sizes (i.e., size of the resulting
search space as represented by GA schemata). Using analysis of variance of
3-factor factorial experiments, we found out that GA performance is affected by
at small problem size (5-city TSP) where the algorithm Partially
Matched Crossover significantly outperforms Cycle Crossover at
confidence level.Comment: 19 page
Towards Input Device Satisfaction Through Hand Anthropometry
We collected the hand anthropometric data of 91 respondents to come up with a
Filipino-based measurement to determine the suitability of an input device for
a digital equipment, the standard PC keyboard. For correlation purposes, we
also collected other relevant information like age, height, province of origin,
and gender, among others. We computed the percentiles for each finger to
classify various finger dimensions and identify length-specific anthropometric
cut-points. We compared the percentiles of each finger dimension against the
actual length of the longest key combinations when correct finger placement is
used for typing, to determine whether the standard PC keyboard is fit for use
by our sampled population. Our analysis shows that the members of the
population with hand dimensions at extended position below 75th percentile and
at 99th percentile are the ones who would most likely not reach the longest key
combination for the left and the right hands, respectively. Using machine
vision and image processing techniques, we automated the anthropometric process
and compared the accuracy of its measurements to that of manual process'. We
compared the measurement generated by our automated anthropometric process with
the measurements using the manual one and we found out that they have a very
minimal absolute difference. The data collected from this study could be used
in other studies such as determining a good design for mobile and other
handheld devices, or input devices other than keyboard. The automated method
that we developed could be used to easily measure hand dimensions given a
digital image of the hand and could be extended for measuring the entire human
body for various other applications.Comment: 20 pages, 12 figures, appeared in A.L. Sioson (ed.) Proceedings
(CDROM) of the 10th National Conference on Information Technology Education
(NCITE 2012), Laoag City, Ilocos Norte, Philippines, 18-20 October 201
Improved Sampling Techniques for Learning an Imbalanced Data Set
This paper presents the performance of a classifier built using the stackingC
algorithm in nine different data sets. Each data set is generated using a
sampling technique applied on the original imbalanced data set. Five new
sampling techniques are proposed in this paper (i.e., SMOTERandRep, Lax Random
Oversampling, Lax Random Undersampling, Combined-Lax Random Oversampling
Undersampling, and Combined-Lax Random Undersampling Oversampling) that were
based on the three sampling techniques (i.e., Random Undersampling, Random
Oversampling, and Synthetic Minority Oversampling Technique) usually used as
solutions in imbalance learning. The metrics used to evaluate the classifier's
performance were F-measure and G-mean. F-measure determines the performance of
the classifier for every class, while G-mean measures the overall performance
of the classifier. The results using F-measure showed that for the data without
a sampling technique, the classifier's performance is good only for the
majority class. It also showed that among the eight sampling techniques, RU and
LRU have the worst performance while other techniques (i.e., RO, C-LRUO and
C-LROU) performed well only on some classes. The best performing techniques in
all data sets were SMOTE, SMOTERandRep, and LRO having the lowest F-measure
values between 0.5 and 0.65. The results using G-mean showed that the
oversampling technique that attained the highest G-mean value is LRO (0.86),
next is C-LROU (0.85), then SMOTE (0.84) and finally is SMOTERandRep (0.83).
Combining the result of the two metrics (F-measure and G-mean), only the three
sampling techniques are considered as good performing (i.e., LRO, SMOTE, and
SMOTERandRep).Comment: 7 pages, 10 figures, 16th Philippine Computing Science Congress (PCSC
2016
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