Abstract: Visibility problems are central to many computational geometry applications. One of the typical visibility problems is computing the view from a given point. In this paper, a linear time procedure is proposed to compute the visibility subsets from a corner of a rectangular prism in an orthogonal polyhedron. The proposed algorithm could be useful to solve classic 3D problems.
Abstract: In language learning, second language learners as well
as Native speakers commit errors in their attempt to achieve
competence in the target language. The realm of collocation has to do
with meaning relation between lexical items. In all human language,
there is a kind of ‘natural order’ in which words are arranged or relate
to one another in sentences so much so that when a word occurs in a
given context, the related or naturally co-occurring word will
automatically come to the mind. It becomes an error, therefore, if
students inappropriately pair or arrange such ‘naturally’ co–occurring
lexical items in a text. It has been observed that most of the second
language learners in this research group commit collocation errors. A
study of this kind is very significant as it gives insight into the kinds
of errors committed by learners. This will help the language teacher
to be able to identify the sources and causes of such errors as well as
correct them thereby guiding, helping and leading the learners
towards achieving some level of competence in the language. The
aim of the study is to understand the nature of these errors as
stumbling blocks to effective essay writing. The objective of the
study is to identify the errors, analyze their structural compositions so
as to determine whether there are similarities between students in this
regard and to find out whether there are patterns to these kinds of
errors which will enable the researcher to understand their sources
and causes. As a descriptive research, the researcher samples some
nine hundred essays collected from three hundred undergraduate
learners of English as a second language in the Federal College of
Education, Kano, North- West Nigeria, i.e. three essays per each
student. The essays which were given on three different lecture times
were of similar thematic preoccupations (i.e. same topics) and length
(i.e. same number of words). The essays were written during the
lecture hour at three different lecture occasions. The errors were
identified in a systematic manner whereby errors so identified were
recorded only once even if they occur severally in students’ essays.
The data was collated using percentages in which the identified
numbers of occurrences were converted accordingly in percentages.
The findings from the study indicate that there are similarities as well
as regular and repeated errors which provided a pattern. Based on the
pattern identified, the conclusion is that students’ collocation errors
are attributable to poor teaching and learning which resulted in wrong
generalization of rules.
Abstract: Excessive vibration means increased wear, increased
repair efforts, bad product selection & quality and high energy
consumption. This may be sometimes experienced by cavitation or
suction/discharge recirculation which could occur only when net
positive suction head available NPSHA drops below the net positive
suction head required NPSHR. Cavitation can cause axial surging, if it
is excessive, will damage mechanical seals, bearings, possibly other
pump components frequently, and shorten the life of the impeller.
Efforts have been made to explain Suction Energy (SE), Specific
Speed (Ns), Suction Specific Speed (Nss), NPSHA, NPSHR & their
significance, possible reasons of cavitation /internal recirculation, its
diagnostics and remedial measures to arrest and prevent cavitation in
this paper. A case study is presented by the author highlighting that
the root cause of unwanted noise and vibration is due to cavitation,
caused by high specific speeds or inadequate net- positive suction
head available which results in damages to material surfaces of
impeller & suction bells and degradation of machine performance, its
capacity and efficiency too. Author strongly recommends revisiting
the technical specifications of CW pumps to provide sufficient NPSH
margin ratios >1.5, for future projects and Nss be limited to 8500 -
9000 for cavitation free operation.
Abstract: A combined heat and power (CHP) system is an efficient and clean way to generate power (electricity). Heat produced by the CHP system can be used for water and space heating. The CHP system which uses hydrogen as fuel produces zero carbon emission. Its’ efficiency can reach more than 80% whereas that of a traditional power station can only reach up to 50% because much of the thermal energy is wasted. The other advantages of CHP systems include that they can decentralize energy generation, improve energy security and sustainability, and significantly reduce the energy cost to the users. This paper presents the economic benefits of using a CHP system in the domestic environment. For this analysis, natural gas is considered as potential fuel as the hydrogen fuel cell based CHP systems are rarely used. UK government incentives for CHP systems are also considered as the added benefit. Results show that CHP requires a significant initial investment in returns it can reduce the annual energy bill significantly. Results show that an investment may be paid back in 7 years. After the back period, CHP can run for about 3 years as most of the CHP manufacturers provide 10 year warranty.
Abstract: Geological structure formed by volcanic activities shows polymorphic characteristics due to repeated cooling and hardening of lava. The Jeju region is showing polymorphic characteristics in which clinker layers are irregularly distributed along with vesicular basalt due to volcanic activities. Accordingly, resident damages and environmental disputes occur frequently in the Jeju region due to blasting. The purpose of this study is to develop a blast vibration equation considering the polymorphic characteristics of basaltic ground in Jeju. The blast vibration equation consists of a functional formula of the blasting vibration constant K that changes according to ground characteristics, and attenuation index n. The case study results in Jeju showed that if there are clinker layers, attenuation index n showed a distribution of -1.32~-1.81, whereas if there are no clinker layers, n was -2.79. Moreover, if there are no clinker layers, the frequency of blast vibration showed a high frequency band from 30Hz to 100Hz, while in rocks with clinker layers it showed a low frequency band from 10Hz to 20Hz.
Abstract: Nanotechnology in pristine sense refers to building of
structures at atomic and molecular scale. Meticulously
nanotechnology encompasses the nanomaterials with at least one
dimension size ranging from 1 to 100 nanometres. Unlike the literal
meaning of its name, nanotechnology is a massive concept beyond
imagination. This paper predominantly deals with relevance of
nanotechnology in automotive industries. New generation of
automotives looks at nanotechnology as an emerging trend of
manufacturing revolution. Intricate shapes can be made out of fairly
inexpensive raw materials instead of conventional fabrication
process. Though the current era have enough technology to face
competition, nanotechnology can give futuristic implications to pick
up the modern pace. Nanotechnology intends to bridge the gap
between automotives with superior technical performance and their
cost fluctuation. Preliminarily, it is an area of great scientific interest
and a major shaper of many new technologies. Nanotechnology can
be an ideal building block for automotive industries, under constant
evolution offering a very wide scope of activity. It possesses huge
potential and is still in the embryonic form of research and
development.
Abstract: E-government has been adopted and used by many governments/countries around the world including Ghana to provide citizens and businesses with more accurate, real-time, and high quality services and information. The objective of this paper is to present an overview of the Government of Ghana’s (GoG) adoption and implement of e-government and its usage by the Ministries, Departments and its agencies (MDAs) as well as other public sector institutions to deliver efficient public service to the general public i.e. citizens, business etc. Government implementation of e-government focused on facilitating effective delivery of government service to the public and ultimately to provide efficient government-wide electronic means of sharing information and knowledge through a network infrastructure developed to connect all major towns and cities, Ministries, Departments and Agencies and other public sector organizations in Ghana. One aim for the Government of Ghana use of ICT in public administration is to improve productivity in government administration and service by facilitating exchange of information to enable better interaction and coordination of work among MDAs, citizens and private businesses. The study was prepared using secondary sources of data from government policy documents, national and international published reports, journal articles, and web sources. This study indicates that through the e-government initiative, currently citizens and businesses can access and pay for services such as renewal of driving license, business registration, payment of taxes, acquisition of marriage and birth certificates as well as application for passport through the GoG electronic service (eservice) and electronic payment (epay) portal. Further, this study shows that there is enormous commitment from GoG to adopt and implement e-government as a tool not only to transform the business of government but also to bring efficiency in public services delivered by the MDAs. To ascertain this, a further study need to be carried out to determine if the use of e-government has brought about the anticipated improvements and efficiency in service delivery of MDAs and other state institutions in Ghana.
Abstract: Energy has a prominent role for development of
nations. Countries which have energy resources also have strategic
power in the international trade of energy since it is essential for all
stages of production in the economy. Thus, it is important for
countries to analyze the weaknesses and strength of the system. On
the other side, international trade is one of the fields that are analyzed
as a complex network via network analysis. Complex network is one
of the tools to analyze complex systems with heterogeneous agents
and interaction between them. A complex network consists of nodes
and the interactions between these nodes. Total properties which
emerge as a result of these interactions are distinct from the sum of
small parts (more or less) in complex systems. Thus, standard
approaches to international trade are superficial to analyze these
systems. Network analysis provides a new approach to analyze
international trade as a network. In this network, countries constitute
nodes and trade relations (export or import) constitute edges. It
becomes possible to analyze international trade network in terms of
high degree indicators which are specific to complex networks such
as connectivity, clustering, assortativity/disassortativity, centrality,
etc. In this analysis, international trade of crude oil and coal which
are types of fossil fuel has been analyzed from 2005 to 2014 via
network analysis. First, it has been analyzed in terms of some
topological parameters such as density, transitivity, clustering etc.
Afterwards, fitness to Pareto distribution has been analyzed via
Kolmogorov-Smirnov test. Finally, weighted HITS algorithm has
been applied to the data as a centrality measure to determine the real
prominence of countries in these trade networks. Weighted HITS
algorithm is a strong tool to analyze the network by ranking countries
with regards to prominence of their trade partners. We have
calculated both an export centrality and an import centrality by
applying w-HITS algorithm to the data. As a result, impacts of the
trading countries have been presented in terms of high-degree
indicators.
Abstract: This paper explored the challenges faced by the
management of a Ghanaian state enterprise in managing conflicts and
disturbances associated with its attempt to implement new work
practices to enhance its capability to operate as a commercial entity.
The purpose was to understand the extent to which organizational
involvement, consistency and adaptability influence employees’
consumption of new work practices in transforming the
organization’s organizational activity system. Using selfadministered
questionnaires, data were collected from one hundred
and eighty (180) employees and analyzed using both descriptive and
inferential statistics. The results showed that constraints in
organizational involvement and adaptability prevented the positive
consumption of new work practices by employees in the
organization. It is also found that the organization’s employees failed
to consume the new practices being implemented, because they
perceived the process as non-involving, and as such, did not
encourage the development of employee capability, empowerment,
and teamwork. The study concluded that the failure of the
organization’s management to create opportunities for organizational
learning constrained its ability to get employees consume the new
work practices, which situation could have facilitated the
organization’s capabilities of operating as a commercial entity.
Abstract: In order to retrieve images efficiently from a large
database, a unique method integrating color and texture features
using genetic programming has been proposed. Opponent color
histogram which gives shadow, shade, and light intensity invariant
property is employed in the proposed framework for extracting color
features. For texture feature extraction, fast discrete curvelet
transform which captures more orientation information at different
scales is incorporated to represent curved like edges. The recent
scenario in the issues of image retrieval is to reduce the semantic gap
between user’s preference and low level features. To address this
concern, genetic algorithm combined with relevance feedback is
embedded to reduce semantic gap and retrieve user’s preference
images. Extensive and comparative experiments have been conducted
to evaluate proposed framework for content based image retrieval on
two databases, i.e., COIL-100 and Corel-1000. Experimental results
clearly show that the proposed system surpassed other existing
systems in terms of precision and recall. The proposed work achieves
highest performance with average precision of 88.2% on COIL-100
and 76.3% on Corel, the average recall of 69.9% on COIL and 76.3%
on Corel. Thus, the experimental results confirm that the proposed
content based image retrieval system architecture attains better
solution for image retrieval.
Abstract: The out-of-band impedance environment is considered
to be of paramount importance in engineering the in-band impedance
environment. Presenting the frequency independent and constant outof-
band impedances across the wide modulation bandwidth is
extremely important for reliable device characterization for future
wireless systems. This paper presents an out-of-band impedance
optimization scheme based on simultaneous engineering of
significant baseband components IF1 (twice the modulation
frequency) and IF2 (four times the modulation frequency) and higher
baseband components such as IF3 (six times the modulation
frequency) and IF4 (eight times the modulation frequency) to
engineer the in-band impedance environment. The investigations
were carried out on a 10W GaN HEMT device driven to deliver a
peak envelope power of approximately 40.5dBm under modulated
excitation. The presentation of frequency independent baseband
impedances to all the significant baseband components whilst
maintaining the optimum termination for fundamental tones as well
as reactive termination for 2nd harmonic under class-J mode of
operation has outlined separate optimum impedances for best
intermodulation (IM) linearity.
Abstract: The study of the aerodynamics related to the
improvement in the acting of airplanes and automobiles with the
objective of being reduced the effect of the attrition of the air on
structures, providing larger speeds and smaller consumption of fuel.
The application of the knowledge of the aerodynamics not more
limits to the aeronautical and automobile industries. Therefore, this
research aims to design and construction of a wind tunnel to perform
aerodynamic analysis in bodies of cars, seeking greater efficiency.
Therefore, this research aims to design and construction of a wind
tunnel to perform aerodynamic analysis in bodies of cars, seeking
greater efficiency. For this, a methodology for wind tunnel type
selection is designed to be built, taking into account the various
existing configurations in which chose to build an open circuit tunnel,
due to the lower complexity of construction and installation;
operational simplicity and low cost. The guidelines for the project
were teaching: the layer that limits study and analyze specimens with
different geometries. For the variation of pressure in the test, section
of a switched gauge used a pitot tube. Thus, it was possible to obtain
quantitative and qualitative results, which proved to be satisfactory.
Abstract: The introduction of a multitude of new and interactive
e-commerce information technology (IT) artifacts has impacted
adoption research. Rather than solely functioning as productivity
tools, new IT artifacts assume the roles of interaction mediators and
social actors. This paper describes the varying roles assumed by IT
artifacts, and proposes and distinguishes between four distinct foci of
how the artifacts are evaluated. It further proposes a theoretical
model that maps the different views of IT artifacts to four distinct
types of evaluations.
Abstract: In this paper, a modified Wilkinson power divider for
GSM application is presented. The quarter–wavelength microstrip
lines in the conventional Wilkinson power divider (WPD) are
replaced by one-eighth wavelength transmission line. Wilkinson
power divider is designed using λ/4 and λ/8 transmission line. It has
the operating frequency of 915 MHz which is used in the GSM
standard. The proposed Wilkinson Power Divider is designed using
the simulation tool Advanced Design System. The results of λ/8
transmission line are very close to the results of λ/4 transmission line.
The isolation loss of λ/8 transmission line is improved by introducing
a capacitor between the output ports. The proposed Wilkinson power
divider has the best return loss of greater than -10 dB and isolation
loss of -15.25 dB. The λ/8 transmission line Wilkinson power divider
has the reduced size of 53.9 percentages than λ/4 transmission line
WPD. The proposed design has simple structure, better isolation loss
and good insertion loss.
Abstract: Scripts are one of the basic text resources to understand
broadcasting contents. Topic modeling is the method to get the
summary of the broadcasting contents from its scripts. Generally,
scripts represent contents descriptively with directions and speeches,
and provide scene segments that can be seen as semantic units.
Therefore, a script can be topic modeled by treating a scene segment
as a document. Because scene segments consist of speeches mainly,
however, relatively small co-occurrences among words in the scene
segments are observed. This causes inevitably the bad quality of
topics by statistical learning method. To tackle this problem, we
propose a method to improve topic quality with additional word
co-occurrence information obtained using scene similarities. The
main idea of improving topic quality is that the information that
two or more texts are topically related can be useful to learn high
quality of topics. In addition, more accurate topical representations
lead to get information more accurate whether two texts are related
or not. In this paper, we regard two scene segments are related
if their topical similarity is high enough. We also consider that
words are co-occurred if they are in topically related scene segments
together. By iteratively inferring topics and determining semantically
neighborhood scene segments, we draw a topic space represents
broadcasting contents well. In the experiments, we showed the
proposed method generates a higher quality of topics from Korean
drama scripts than the baselines.
Abstract: The early-stage damage detection in offshore
structures requires continuous structural health monitoring and for the
large area the position of sensors will also plays an important role in
the efficient damage detection. Determining the dynamic behavior of
offshore structures requires dense deployment of sensors. The wired
Structural Health Monitoring (SHM) systems are highly expensive
and always needs larger installation space to deploy. Wireless sensor
networks can enhance the SHM system by deployment of scalable
sensor network, which consumes lesser space. This paper presents the
results of wireless sensor network based Structural Health Monitoring
method applied to a scaled experimental model of offshore structure
that underwent wave loading. This method determines the
serviceability of the offshore structure which is subjected to various
environment loads. Wired and wireless sensors were installed in the
model and the response of the scaled BLSRP model under wave
loading was recorded. The wireless system discussed in this study is
the Raspberry pi board with Arm V6 processor which is programmed
to transmit the data acquired by the sensor to the server using Wi-Fi
adapter, the data is then hosted in the webpage. The data acquired
from the wireless and wired SHM systems were compared and the
design of the wireless system is verified.
Abstract: This paper presents the experimental results of 11 kV
and 33 kV silicon composite insulators under artificial salt and urea
polluted conditions. The tests were carried out under different
seasons like summer, winter, and monsoon. The artificial pollution is
prepared by properly dissolving the salt and urea in the water. The
prepared salt and urea pollutions are sprayed on the insulators and
dried up for sufficiently large time. The process is continued until a
uniform layer is formed on the surface of insulator. For each insulator
rating, four samples were tested. The maximum leakage current and
breakdown voltage were measured. From experimental data,
performance of test specimen is evaluated by comparing breakdown
voltage and leakage current during different seasons when exposed to
salt and urea polluted conditions. From these results the performance
of the insulators can be predicted when they are installed in
industrial, agricultural, and coastal areas. The experimental tests were
carried out in the High Voltage laboratory using two stage cascade
transformer having the rating of 1000 kVA, 500 kV.
Abstract: The study assessed the effectiveness of Pawpaw
(Carica papaya) wood in reducing the concentrations of heavy
metals in wastewater acting as a bio-sorbent. The following heavy
metals were considered; Zinc, Cadmium, Lead, Copper, Iron,
Selenium, Nickel and Manganese. The physiochemical properties of
Carica papaya stem were studied. The experimental sample was
sourced from the trunk of a felled matured pawpaw tree. Wastewater
for experimental use was prepared by dissolving soil samples
collected from a dump site at Owerri, Imo state of Nigeria in water.
The concentration of each metal remaining in solution as residual
metal after bio-sorption was determined using Atomic absorption
Spectrometer. The effects of pH and initial heavy metal concentration
were studied in a batch reactor. The results of Spectrometer test
showed that there were different functional groups detected in the
Carica papaya stem biomass. There was increase in metal removal as
the pH increased for all the metals considered except for Nickel and
Manganese. Optimum bio-sorption occurred at pH 5.9 with 5g/100ml
solution of bio-sorbent. The results of the study showed that the
treated wastewater is fit for irrigation purpose based on Canada
wastewater quality guideline for the protection of Agricultural
standard. This approach thus provides a cost effective and
environmentally friendly option for treating wastewater.
Abstract: Fermentation is well known as an essential process to
develop chocolate flavor in dried cocoa beans. Besides developing
the precursor of cocoa flavor, it also induces the color changes in the
beans. The fermentation process is influenced by various factors such
as planting material, preconditioning of cocoa pod and fermentation
technique. Therefore, this study was conducted to evaluate color of
Malaysian cocoa beans and how the duration of pods storage and
fermentation technique using shallow box will effect on its color
characteristics. There are two factors being studied i.e. duration of
cocoa pod storage (0, 2, 4 and 6 days) and duration of cocoa
fermentation (0, 1, 2, 3, 4 and 5 days). The experiment is arranged in
4 x 6 factorial designs with 24 treatments and arrangement is in a
Completely Randomised Design (CRD). The produced beans are
inspected for color changes under artificial light during cut test and
divided into four groups of color namely fully brown, purple brown,
fully purple and slaty. Cut tests indicated that cocoa beans which are
directly dried without undergone fermentation has the highest slaty
percentage. However, application of pods storage before fermentation
process is found to decrease the slaty percentage. In contrast, the
percentages of fully brown beans start to dominate after two days of
fermentation, especially from four and six days of pods storage batch.
Whereas, almost all batches of cocoa beans have a percentage of fully
purple less than 20%. Interestingly, the percentage of purple brown
beans are scattered in the entire beans batch regardless any specific
trend. Meanwhile, statistical analysis using General Linear Model
showed that the pods storage has a significant effect on the color
characteristic of the Malaysian dried beans compared to fermentation
duration.
Abstract: The field of instrumentation electronics is undergoing
an explosive growth, due to its wide range of applications. The
proliferation of electrical devices in a close working proximity can
negatively influence each other’s performance. The degradation in
the performance is due to electromagnetic interference (EMI). This paper investigates the negative effects of electromagnetic
interference originating in the General Purpose Interface Bus (GPIB)
control-network of the AC-DC transfer measurement system.
Remedial measures of reducing measurement errors and failure of
range of industrial devices due to EMI have been explored. The ACDC
transfer measurement system was analysed for the commonmode
(CM) EMI effects. Further investigation of coupling path as
well as much accurate identification of noise propagation mechanism
has been outlined. To prevent the occurrence of common-mode
(ground loops) which was identified between the GPIB system
control circuit and the measurement circuit, a microcontroller-driven
GPIB switching isolator device was designed, prototyped,
programmed and validated. This mitigation technique has been
explored to reduce EMI effectively.