Abstract: Dissimilar joining of Titanium and Aluminum thin
sheets has potential applications in aerospace and automobile
industry which can reduce weight and cost and improve strength,
corrosion resistance and high temperature properties. However
successful welding of Titanium/Aluminium sheets is of challenge due
to differences in physical, chemical and metallurgical properties
between the two. This paper describes research results of Laser Beam
Welding (LBW) of Ti/Al thin sheets in which many researchers have
recently performed and critically reviewed from different
perspectives. Also some of notable works in the field of laser welding
with changes in mechanical properties, crack propagation, diffusion
behavior, chemical potential, interfacial reaction and the
microstructure are reported.
Abstract: City shrinkage is one of the thorny problems that many
European cities have to face with nowadays. It is mainly expressed as
the decrease of population in these cities. Eastern Germany is one of
the pioneers of European shrinking cities with long shrinking history.
The paper selects one representative shrinking city Halle (Saale) in
eastern Germany as research objective, collecting and investigating
nearly 20 years (1993-2010) municipal data after the reunification of
Germany. These data based on five dimensions, which are
demographic, economic, social, spatial and environmental and total 16
eligible variables. Factor Analysis is used to deal with these variables
in order to assess the most important factors affecting shrinking Halle.
The results show that there are three main factors determine the
shrinkage of Halle, respectively named “demographical and
economical factor”, “social stability factor”, and “city vitality factor”.
The three factors act at different time period of Halle’s shrinkage: from
1993 to 1997 the demographical and economical factor played an
important role; from 1997 to 2004 the social stability factor is
significant to city shrinkage; since 2005 city vitality factor determines
the shrinkage of Halle. In recent years, the shrinkage in Halle mitigates
that shows the sign of growing population. Thus the city Halle should
focus on attaching more importance on the city vitality factor to
prevent the city from shrinkage. Meanwhile, the city should possess a
positive perspective to shift the growth-oriented development to tap
the potential of shrinking cities. This method is expected to apply to
further research and other shrinking cities
Abstract: In a highly competitive environment, it becomes more
important to shorten the whole business process while delivering or
even enhancing the business value to the customers and suppliers.
Although the workflow management systems receive much attention
for its capacity to practically support the business process enactment,
the effective workflow modeling method remain still challenging and
the high degree of process complexity makes it more difficult to gain
the short lead time. This paper presents a workflow structuring method
in a holistic way that can reduce the process complexity using
activity-needs and formal concept analysis, which eventually enhances
the key performance such as quality, delivery, and cost in business
process.
Abstract: Botnets are one of the most serious and widespread
cyber threats. Today botnets have been facilitating many
cybercrimes, especially financial, top secret thefts. Botnets can be
available for lease in the market and are utilized by the
cybercriminals to launch massive attacks like DDoS, click fraud,
phishing attacks etc., Several large institutions, hospitals, banks,
government organizations and many social networks such as twitter,
facebook etc., became the target of the botmasters. Recently,
noteworthy researches have been carried out to detect bot, C&C
channels, botnet and botmasters. Using many sophisticated
technologies, botmasters made botnet a titan of the cyber world.
Innumerable challenges have been put forth by the botmasters to the
researchers in the detection of botnet. In this paper we present a
survey of different types of botnet C&C channels and also provide a
comparison of various botnet categories. Finally we hope that our
survey will create awareness for forthcoming botnet research
endeavors.
Abstract: Taro Scarab beetles (Papuana uninodis, Coleoptera:
Scarabaeidae) inflict severe damage on important root crops and
plants such as Taro or Cocoyam, yam, sweet potatoes, oil palm and
coffee tea plants across Africa and Asia resulting in economic
hardship and starvation in some nations. Scoliid wasps and
Metarhizium anisopliae fungus - bio-control agents; are shown to be
able to control the population of Scarab beetle adults and larvae using
a newly created simulation model based on non-linear ordinary
differential equations that track the populations of the beetle life
cycle stages: egg, larva, pupa, adult and the population of the scoliid
parasitoid wasps, which attack beetle larvae. In spite of the challenge
driven by the longevity of the scarab beetles, the combined effect of
the larval wasps and the fungal bio-control agent is able to control
and drive down the population of both the adult and the beetle eggs
below the environmental carrying capacity within an interval of 120
days, offering the long term prospect of a stable and eco-friendly
environment; where the population of scarab beetles is: regulated by
parasitoid wasps and beneficial soil saprophytes.
Abstract: The purpose of this study was to investigate
perceptions of climate change risk to forest ecosystems and forestbased
communities as well as perceived effectiveness of adaptation
strategies for climate change as well as challenges for adaptation.
Data was gathered using a pre-tested semi-structured questionnaire.
Simple random selection technique was applied. For the majority of
issues, the responses were obtained on multi-point likert scales, and
the scores provided were, in turn, used to estimate the means and
other useful estimates. A composite knowledge index developed
using correct responses to a set of self-rated statements were used to
evaluate the issues. The mean of the knowledge index was 0.64. Also
all respondents recorded values of the knowledge index above 0.25.
Increase forest fire was perceived by respondents as the greatest risk
to forest eco-system. Decrease access to water supplies was perceived
as the greatest risk to livelihoods of forest based communities. The
most effective adaptation strategy relevant to climate change risks to
forest eco-systems and forest based communities livelihoods in
Kathmandu valley in Nepal as perceived by the respondents was
reforestation and afforestation. As well, lack of public awareness was
perceived as the major limitation for climate change adaptation.
However, perceived risks as well as effective adaptation strategies
showed an inconsistent association with knowledge indicators and
social-cultural variables. The results provide useful information to
any party who involve with climate change issues in Nepal, since
such attempts would be more effective once the people’s perceptions
on these aspects are taken into account.
Abstract: Distributed Generation (DG) can help in reducing the
cost of electricity to the costumer, relieve network congestion and
provide environmentally friendly energy close to load centers. Its
capacity is also scalable and it provides voltage support at distribution
level. Hence, DG placement and penetration level is an important
problem for both the utility and DG owner. DG allocation and capacity
determination is a nonlinear optimization problem. The objective
function of this problem is the minimization of the total loss of the
distribution system. Also high levels of penetration of DG are a new
challenge for traditional electric power systems. This paper presents a
new methodology for the optimal placement of DG and penetration
level of DG in distribution system based on General Algebraic
Modeling System (GAMS) and Genetic Algorithm (GA).
Abstract: This study offers a comprehensive review of the
research papers published in the field of cooling towers and gives an
insight into the latest developments of the natural draught cooling
towers. Different modeling, analysis and design techniques are
summarized and the challenges are discussed. The 118 references
included in this paper are mostly concentrated on the review of the
published papers after 2005. The present paper represents a complete
collection of the studies done for cooling towers and would give an
updated material for the researchers and design engineers in the field
of hyperbolic cooling towers.
Abstract: One of the biggest challenges facing Theological/
Religious Education in Nigeria is access to quality learning materials.
For instance at the Trinity (Union) Theological College, Umuahia, it
was difficult for lecturers to access suitable and qualitative materials
for instruction especially the ones that would suit the African context
and stimulate a deep rooted interest among the students. Some
textbooks written by foreign authors were readily available in the
School Library, but were lacking in the College bookshops for
students to own copies. Even when the College was able to order
some of the books from abroad, it did not usher in the needed
enthusiasm expected from the students because they were either very
expensive or very difficult to understand during private studies. So it
became necessary to develop contextual materials which were
affordable and understandable, though with little success. The
National Open University of Nigeria (NOUN)’s innovation in the
development and sharing of learning resources through its Open
Courseware is a welcome development and of great assistance to
students. Apart from NOUN students who could easily access the
materials, many others from various theological/religious institutes
across the nation have benefited immensely. So, the thesis of this
paper is that the promotion of open educational resources in
theological/religious education in Nigeria would facilitate a better
informed/equipped religious leadership, which would in turn impact
its adherents for a healthier society and national development.
Adopting a narrative and historical approach within the context of
Nigeria’s educational system, the paper discusses: educational
traditions in Nigeria; challenges facing theological/religious
education in Nigeria; and benefits of open educational resources. The
study goes further to making recommendations on how OER could
positively influence theological/religious education in Nigeria. It is
expected that theologians, religious educators, and ODL practitioners
would find this work very useful.
Abstract: The aim of this paper is to trace the historical
development of the accounting profession in Libya, in order to
identify challenges facing the profession as the country moves from a
closed to emerging economy. The study is based on a literature
review and archival research. Accounting information has a vital role
to play in the achievement of economic goals in developing and
emerging economies, but a well qualified accounting profession is
required. In the context of institutional instability and unique cultural
factors, the accounting profession in Libya faces educational and
legal challenges if it is to achieve its potential in assisting the country
to reach its economic goals. This study focuses on one country,
which does limit its generalisability. However, it also suggests
fruitful research areas in considering the impact and challenge of
historic factors on the accounting profession in emerging economies.
Centrally planned economies require a body of well trained
professional accountants if they are to emerge onto the global
economic arena. Studies on the accounting profession have focused
primarily on those in developed economies, where the need for
meaningful accounting information for decision making is taken for
granted and there is a well trained, professional workforce. This study
of the profession in an emerging economy highlights the efforts that
will be needed to ensure the contribution of the profession to the
economic wellbeing of other emerging economies.
Abstract: Multispectral screening systems are becoming more
popular because of their very interesting properties and applications.
One of the most significant applications of multispectral screening
systems is prevention of terrorist attacks. There are many kinds of
threats and many methods of detection. Visual detection of objects
hidden under clothing of a person is one of the most challenging
problems of threats detection. There are various solutions of the
problem; however, the most effective utilize multispectral
surveillance imagers. The development of imaging devices and
exploration of new spectral bands is a chance to introduce new
equipment for assuring public safety. We investigate the possibility
of long lasting detection of potentially dangerous objects covered
with various types of clothing. In the article we present the results of
comparative studies of passive imaging in three spectrums – visible,
infrared and terahertz.
Abstract: The purpose of the present work is to review some
data for the management challenges that the aquaculture industry in
Greece is currently facing. The results indicate that Greek
aquaculture fish farms apply Human Resources Management (HRM)
practices which can increase motivation, commitment and job
satisfaction of their personnel. In turn, these practices can increase
the productivity of the business. The Greek fish farms appear to
invest in research and technological innovation with a good record in
research activities and the generation of patents. Interestingly, the
results of the present work were carried out during the period of the
recent economic crisis in Greece. Several sectors of the Greek
economy were severely affected by the financial problems of the
Greek government and the Greek banks. Under the adverse
economical conditions created by the Greek economic crisis, even the
Greek aquaculture industry, which historically is considered as a
thriving national exporting business sector, experienced harsh
economic and market conditions. As a result of the global, European
and national economic crisis, consumption of fish dropped while
companies had to hold most of their stocked fish in order to regulated
the flow to the market and the price. This occurred at a time where
Banks in Greece had their own financial crisis – banking crisis -
which resulted in limited access to lending for the all business sectors
of the national economy including the Greek aquaculture industry. In
spite of these economic conditions, the Greek aquaculture industry,
after a series of mergers and acquisitions, has now stabilized
production and exhibits very good prospects for future growth.
Evidently, the firms had to cut salaries and on some occasions even
pay their staff in arrears. Nevertheless, the results presented in this
paper indicate that during the economic crisis, the surveyed fish
farms maintained their HRM practices, investing in their human
capital and technological input. In fact, human capital and
technological input are the ticket for future success of companies in
any business sector.
Abstract: The systematic evaluation of manufacturing
technologies with regard to the potential for product designing
constitutes a major challenge. Until now, conventional evaluation
methods primarily consider the costs of manufacturing technologies.
Thus, the potential of manufacturing technologies for achieving
additional product design features is not completely captured. To
compensate this deficit, final evaluations of new technologies are
mainly intuitive in practice. Therefore, an additional evaluation
dimension is needed which takes the potential of manufacturing
technologies for specific realizable product designs into account. In
this paper, we present the approach of an evaluation method for
selecting manufacturing technologies with regard to their potential
for product designing. This research is done within the Fraunhofer
innovation cluster »AdaM« (Adaptive Manufacturing) which targets
the development of resource efficient and adaptive manufacturing
technology processes for complex turbomachinery components.
Abstract: Health analytics (HA) is used in healthcare systems
for effective decision making, management and planning of
healthcare and related activities. However, user resistances, unique
position of medical data content and structure (including
heterogeneous and unstructured data) and impromptu HA projects
have held up the progress in HA applications. Notably, the accuracy
of outcomes depends on the skills and the domain knowledge of the
data analyst working on the healthcare data. Success of HA depends
on having a sound process model, effective project management and
availability of supporting tools. Thus, to overcome these challenges
through an effective process model, we propose a HA process model
with features from rational unified process (RUP) model and agile
methodology.
Abstract: Recent advances in wireless networking technologies
introduce several energy aware routing protocols in sensor networks.
Such protocols aim to extend the lifetime of network by reducing the
energy consumption of nodes. Many researchers are looking for
certain challenges that are predominant in the grounds of energy
consumption. One such protocol that addresses this energy
consumption issue is ‘Cluster based hierarchical routing protocol’. In
this paper, we intend to discuss some of the major hierarchical
routing protocols adhering towards sensor networks. Furthermore, we
examine and compare several aspects and characteristics of few
widely explored hierarchical clustering protocols, and its operations
in wireless sensor networks (WSN). This paper also presents a
discussion on the future research topics and the challenges of
hierarchical clustering in WSNs.
Abstract: Economic Dispatch (ED) is one of the most
challenging problems of power system since it is difficult to determine
the optimum generation scheduling to meet the particular load demand
with the minimum fuel costs while all constraints are satisfied. The
objective of the Economic Dispatch Problems (EDPs) of electric
power generation is to schedule the committed generating units
outputs so as to meet the required load demand at minimum operating
cost while satisfying all units and system equality and inequality
constraints. In this paper, an efficient and practical steady-state genetic
algorithm (SSGAs) has been proposed for solving the economic
dispatch problem. The objective is to minimize the total generation
fuel cost and keep the power flows within the security limits. To
achieve that, the present work is developed to determine the optimal
location and size of capacitors in transmission power system where,
the Participation Factor Algorithm and the Steady State Genetic
Algorithm are proposed to select the best locations for the capacitors
and determine the optimal size for them.
Abstract: The study deals with the challenges in developing a
test rig to test the performance of water lubricated journal bearing.
The test rig is designed to simulate the working conditions of the
bearing in order to understand their performance before they are put
in operation. The bearing that is studied is the commercially available
water lubricated bearing which has a rubber liner bonded with a rigid
metal shell. The lubricant enters the bearing axially through a
pressurized inlet tank and exits to an outlet tank which is at
sufficiently low pressure. The load on the bearing is applied through
the dead weight system which acts both in upward and downward
direction so that net load acts on the bearing. The issues in feeding
the lubricant into the bearing from the inlet side and preventing the
leakage of the lubricant is discussed. The application of the load on
the test bearing while maintaining the bearing afloat is also discussed.
Abstract: Access control is one of the most challenging issues
facing information security. Access control is defined as, the ability to
permit or deny access to a particular computational resource or digital
information by an unauthorized user or subject. The concept of usage
control (UCON) has been introduced as a unified approach to capture a
number of extensions for access control models and systems. In
UCON, an access decision is determined by three factors:
authorizations, obligations and conditions. Attribute mutability and
decision continuity are two distinct characteristics introduced by
UCON for the first time. An observation of UCON components
indicates that, the components are predefined and static. In this paper,
we propose a new and flexible model of usage control for the creation
and elimination of some of these components; for example new
objects, subjects, attributes and integrate these with the original
UCON model. We also propose a model for concurrent usage
scenarios in UCON.
Abstract: This paper explores competencies that managers of
small firms in Ghana use to enhance operational flexibility towards
the attainment of higher productivity. This is because the requisite
competence required of such managers to be effective performers
continues to be a challenge. Data was collected from managers of
three hundred small firms using a standardized self-completion
questionnaire and analyzed using the Amos-based structural equation
model approach. Findings from factor and confirmatory factor
analyses showed that the only competence exhibited by managers
toward effective performance is realistic practices evident at the
workplace. It is concluded that a manager’s self-confidence and
involvement in areas that he/she is good at, and his/her possession of
skills that enables performance at high capacity are indications of the
manger’s effectiveness. The study outcome provides a knowledge
base helpful to policy-makers, especially in Ghana, in determining
the requisite managerial competences required by small firm
managers for effective performance.
Abstract: Over the past era, there have been a lot of efforts and
studies are carried out in growing proficient tools for performing
various tasks in big data. Recently big data have gotten a lot of
publicity for their good reasons. Due to the large and complex
collection of datasets it is difficult to process on traditional data
processing applications. This concern turns to be further mandatory
for producing various tools in big data. Moreover, the main aim of
big data analytics is to utilize the advanced analytic techniques
besides very huge, different datasets which contain diverse sizes from
terabytes to zettabytes and diverse types such as structured or
unstructured and batch or streaming. Big data is useful for data sets
where their size or type is away from the capability of traditional
relational databases for capturing, managing and processing the data
with low-latency. Thus the out coming challenges tend to the
occurrence of powerful big data tools. In this survey, a various
collection of big data tools are illustrated and also compared with the
salient features.