Abstract: An adaptive neural network controller for
autonomous underwater vehicles (AUVs) is presented in this paper.
The AUV model is highly nonlinear because of many factors, such as
hydrodynamic drag, damping, and lift forces, Coriolis and centripetal
forces, gravity and buoyancy forces, as well as forces from thruster.
In this regards, a nonlinear neural network is used to approximate the
nonlinear uncertainties of AUV dynamics, thus overcoming some
limitations of conventional controllers and ensure good performance.
The uniform ultimate boundedness of AUV tracking errors and the
stability of the proposed control system are guaranteed based on
Lyapunov theory. Numerical simulation studies for motion control of
an AUV are performed to demonstrate the effectiveness of the
proposed controller.
Abstract: Rural villagers in Thailand have unique skill for producing craft using local materials. However, the appearance and function of their products are not suited to the demand of international market. The Thai government policy on sustainable economy emphasises the necessity to incorporate a design strategy that will draw out the unique qualities and add value to the products, while raising the satisfaction of international consumer. As an industrial designer, the author sees opportunities that design can enhance sustainability of Thai local products through the potentials that available in village-based enterprises. This research attempts to address, how best use design to practically solve the problems in the development of Thais product in. The privilege solution is expressed through the design of design strategy that supports sustain economic development of microenterprise in Thailand in the way that aligns with product design development. This consideration integrates together with global business outlook in the development of products from rural communities.
Abstract: A road pricing game is a game where various stakeholders and/or regions with different (and usually conflicting) objectives compete for toll setting in a given transportation network to satisfy their individual objectives. We investigate some classical game theoretical solution concepts for the road pricing game. We establish results for the road pricing game so that stakeholders and/or regions playing such a game will beforehand know what is obtainable. This will save time and argument, and above all, get rid of the feelings of unfairness among the competing actors and road users. Among the classical solution concepts we investigate is Nash equilibrium. In particular, we show that no pure Nash equilibrium exists among the actors, and further illustrate that even “mixed Nash equilibrium" may not be achievable in the road pricing game. The paper also demonstrates the type of coalitions that are not only reachable, but also stable and profitable for the actors involved.
Abstract: Due to today-s turbulent environment, manufacturing resources, particularly in assembly, must be reconfigured frequently. These reconfigurations are caused by various, partly cyclic, influencing factors. Hence, it is important to evaluate the innovation ability - the capability of resources to implement innovations quickly and efficiently without large expense - of manufacturing resources. For this purpose, a new methodology is presented in this article. Within the methodology, design structure matrices and graph theory are used. The results of the methodology include different indices to evaluate the innovation ability of the manufacturing resources. Due to the cyclicity of the influencing factors, the methodology can be used to synchronize the realization of adaptations.
Abstract: The SOM has several beneficial features which make
it a useful method for data mining. One of the most important
features is the ability to preserve the topology in the projection.
There are several measures that can be used to quantify the goodness
of the map in order to obtain the optimal projection, including the
average quantization error and many topological errors. Many
researches have studied how the topology preservation should be
measured. One option consists of using the topographic error which
considers the ratio of data vectors for which the first and second best
BMUs are not adjacent. In this work we present a study of the
behaviour of the topographic error in different kinds of maps. We
have found that this error devaluates the rectangular maps and we
have studied the reasons why this happens. Finally, we suggest a new
topological error to improve the deficiency of the topographic error.
Abstract: This paper tests the level of market integration between Malaysia and Singapore stock markets with the world market. Kalman Filter (KF) methodology is used on the International Capital Asset Pricing Model (ICAPM) and the pricing errors estimated within the framework of ICAPM are used as a measure of market integration or segmentation. The advantage of the KF technique is that it allows for time-varying coefficients in estimating ICAPM and hence able to capture the varying degree of market integration. Empirical results show clear evidence of varying degree of market integration for both case of Malaysia and Singapore. Furthermore, the results show that the changes in the level of market integration are found to coincide with certain economic events that have taken placed. The findings certainly provide evidence on the practicability of the KF technique to estimate stock markets integration. In the comparison between Malaysia and Singapore stock market, the result shows that the trends of the market integration indices for Malaysia and Singapore look similar through time but the magnitude is notably different with the Malaysia stock market showing greater degree of market integration. Finally, significant evidence of varying degree of market integration shows the inappropriate use of OLS in estimating the level of market integration.
Abstract: In the LFC problem, the interconnections among some areas are the input of disturbances, and therefore, it is important to suppress the disturbances by the coordination of governor systems. In contrast, tie-line power flow control by TCPS located between two areas makes it possible to stabilize the system frequency oscillations positively through interconnection, which is also expected to provide a new ancillary service for the further power systems. Thus, a control strategy using controlling the phase angle of TCPS is proposed for provide active control facility of system frequency in this paper. Also, the optimum adjustment of PID controller's parameters in a robust way under bilateral contracted scenario following the large step load demands and disturbances with and without TCPS are investigated by Particle Swarm Optimization (PSO), that has a strong ability to find the most optimistic results. This newly developed control strategy combines the advantage of PSO and TCPS and has simple stricture that is easy to implement and tune. To demonstrate the effectiveness of the proposed control strategy a three-area restructured power system is considered as a test system under different operating conditions and system nonlinearities. Analysis reveals that the TCPS is quite capable of suppressing the frequency and tie-line power oscillations effectively as compared to that obtained without TCPS for a wide range of plant parameter changes, area load demands and disturbances even in the presence of system nonlinearities.
Abstract: In this paper, we consider a multi user multiple input
multiple output (MU-MIMO) based cooperative reporting system for
cognitive radio network. In the reporting network, the secondary
users forward the primary user data to the common fusion center
(FC). The FC is equipped with linear equalizers and an energy
detector to make the decision about the spectrum. The primary user
data are considered to be a digital video broadcasting - terrestrial
(DVB-T) signal. The sensing channel and the reporting channel are
assumed to be an additive white Gaussian noise and an independent
identically distributed Raleigh fading respectively. We analyzed the
detection probability of MU-MIMO system with linear equalizers and
arrived at the closed form expression for average detection
probability. Also the system performance is investigated under
various MIMO scenarios through Monte Carlo simulations.
Abstract: This research study the application of the immobilized
TiO2 layer and Cu-TiO2 layer on graphite substrate as a negative
electrode or anode for Li-ion battery. The titania layer was produced
through chemical bath deposition method, meanwhile Cu particles
were deposited electrochemically. A material can be used as an
electrode as it has capability to intercalates Li ions into its crystal
structure. The Li intercalation into TiO2/Graphite and Cu-
TiO2/Graphite were analyzed from the changes of its XRD pattern
after it was used as electrode during discharging process. The XRD
patterns were refined by Le Bail method in order to determine the
crystal structure of the prepared materials. A specific capacity and the
cycle ability measurement were carried out to study the performance
of the prepared materials as negative electrode of the Li-ion battery.
The specific capacity was measured during discharging process from
fully charged until the cut off voltage. A 300 was used as a load.
The result shows that the specific capacity of Li-ion battery with
TiO2/Graphite as negative electrode is 230.87 ± 1.70mAh.g-1 which is
higher than the specific capacity of Li-ion battery with pure graphite
as negative electrode, i.e 140.75 ±0.46mAh.g-1. Meanwhile
deposition of Cu onto TiO2 layer does not increase the specific
capacity, and the value even lower than the battery with
TiO2/Graphite as electrode. The cycle ability of the prepared battery
is only two cycles, due to the Li ribbon which was used as cathode
became fragile and easily broken.
Abstract: The research investigates the effects of super plasticizer and molarity of sodium hydroxide alkaline solution on the workability, microstructure and compressive strength of self compacting geopolymer concrete (SCGC). SCGC is an improved way of concreting execution that does not require compaction and is made by complete elimination of ordinary Portland cement content. The parameters studied were superplasticizer (SP) dosage and molarity of NaOH solution. SCGC were synthesized from low calcium fly ash, activated by combinations of sodium hydroxide and sodium silicate solutions, and by incorporation of superplasticizer for self compactability. The workability properties such as filling ability, passing ability and resistance to segregation were assessed using slump flow, T-50, V-funnel, L-Box and J-ring test methods. It was found that the essential workability requirements for self compactability according to EFNARC were satisfied. Results showed that the workability and compressive strength improved with the increase in superplasticizer dosage. An increase in strength and a decrease in workability of these concrete samples were observed with the increase in molarity of NaOH solution from 8M to 14M. Improvement of interfacial transition zone (ITZ) and micro structure with the increase of SP and increase of concentration from 8M to 12M were also identified.
Abstract: Current mode circuits like current conveyors are
getting significant attention in current analog ICs design due to their
higher band-width, greater linearity, larger dynamic range, simpler
circuitry, lower power consumption and less chip area. The second
generation current controlled conveyor (CCCII) has the advantage of
electronic adjustability over the CCII i.e. in CCCII; adjustment of the
X-terminal intrinsic resistance via a bias current is possible. The
presented approach is based on the CMOS implementation of second
generation positive (CCCII+), negative (CCCII-) and dual Output
Current Controlled Conveyor (DOCCCII) and its application as
Universal filter. All the circuits have been designed and simulated
using 65nm CMOS technology model parameters on Cadence
Virtuoso / Spectre using 1V supply voltage. Various simulations have
been carried out to verify the linearity between output and input
ports, range of operation frequency, etc. The outcomes show good
agreement between expected and experimental results.
Abstract: Plastics occupy wide place in the applications of
automotive, electronics and house goods. Especially reinforced
plastics become popular because of their high strength besides their
advantages of low weight and easy manufacturability. In this study,
mechanical and morphological properties of polypropylene (PP) and
high density polyethylene (HDPE) matrix composites reinforced with
surface modified nano titan dioxide (TiO2) particles were
investigated. Surface modification was made by coating the nano
powders with maleic anhydride grafted styrene ethylene butylene
styrene (SEBS-g-MA) and silane, respectively. After surface
modification, PP/TiO2 and HDPE/TiO2 composites were obtained by
using twin screw extruder at titan dioxide loading of 1 wt.%, 3 wt.%
and 5 wt.%. Effects of surface modification were determined by
thermal and morphological analysis. SEBS-g-MA provided bridging
effect between TiO2 particles and polymer matrix while silane was
effective as a dispersant. Depending on that, homogenous structures
without agglomeration were obtained. Mechanical tests were
performed on the injection moldings of the composites for obtaining
the impact strength, tensile strength, stress at break, elongation and
elastic modulus. Reinforced HDPE and PP moldings gave higher
tensile strength and elastic modulus due to the rigid structure of TiO2.
Slight increment was seen in stress at break. Elongation and impact
strength decreased due to the stiffness of the nano titan dioxide.
Abstract: In this paper, our focus is to assure a global frequency synchronization in OFDMA-based wireless mesh networks with local information. To acquire the global synchronization in distributed manner, we propose a novel distributed frequency synchronization (DFS) method. DFS is a method that carrier frequencies of distributed nodes converge to a common value by repetitive estimation and averaging step and sharing step. Experimental results show that DFS achieves noteworthy better synchronization success probability than existing schemes in OFDMA-based mesh networks where the estimation error is presented.
Abstract: Fast development of technologies, economic globalization and many other external circumstances stimulate company’s competitiveness. One of the major trends in today’s business is the shift to the exploitation of the Internet and electronic environment for entrepreneurial needs. Latest researches confirm that e-environment provides a range of possibilities and opportunities for companies, especially for micro-, small- and medium-sized companies, which have limited resources. The usage of e-tools raises the effectiveness and the profitability of an organization, as well as its competitiveness.
In the electronic market, as in the classic one, there are factors, such as globalization, development of new technology, price sensitive consumers, Internet, new distribution and communication channels that influence entrepreneurship. As a result of eenvironment development, e-commerce and e-marketing grow as well.
Objective of the paper: To describe and identify factors influencing company’s competitiveness in e-environment.
Research methodology: The authors employ well-established quantitative and qualitative methods of research: grouping, analysis, statistics method, factor analysis in SPSS 20 environment, etc. The theoretical and methodological background of the research is formed by using scientific researches and publications, such as that from mass media and professional literature; statistical information from legal institutions as well as information collected by the authors during the surveying process.
Research result: The authors detected and classified factors influencing competitiveness in e-environment.
In this paper, the authors presented their findings based on theoretical, scientific, and field research. Authors have conducted a research on e-environment utilization among Latvian enterprises.
Abstract: This paper argues that increased uncertainty, in certain
situations, may actually encourage investment. Since earlier studies
mostly base their arguments on the assumption of geometric Brownian
motion, the study extends the assumption to alternative stochastic
processes, such as mixed diffusion-jump, mean-reverting process, and
jump amplitude process. A general approach of Monte Carlo
simulation is developed to derive optimal investment trigger for the
situation that the closed-form solution could not be readily obtained
under the assumption of alternative process. The main finding is that
the overall effect of uncertainty on investment is interpreted by the
probability of investing, and the relationship appears to be an invested
U-shaped curve between uncertainty and investment. The implication
is that uncertainty does not always discourage investment even under
several sources of uncertainty. Furthermore, high-risk projects are not
always dominated by low-risk projects because the high-risk projects
may have a positive realization effect on encouraging investment.
Abstract: Total liquid ventilation can support gas exchange in animal models of lung injury. Clinical application awaits further technical improvements and performance verification. Our aim was to develop a liquid ventilator, able to deliver accurate tidal volumes, and a computerized system for measuring lung mechanics. The computer-assisted, piston-driven respirator controlled ventilatory parameters that were displayed and modified on a real-time basis. Pressure and temperature transducers along with a lineal displacement controller provided the necessary signals to calculate lung mechanics. Ten newborn lambs (
Abstract: In this article, a formal specification and verification of the Rabin public-key scheme in a formal proof system is presented. The idea is to use the two views of cryptographic verification: the computational approach relying on the vocabulary of probability theory and complexity theory and the formal approach based on ideas and techniques from logic and programming languages. A major objective of this article is the presentation of the first computer-proved implementation of the Rabin public-key scheme in Isabelle/HOL. Moreover, we explicate a (computer-proven) formalization of correctness as well as a computer verification of security properties using a straight-forward computation model in Isabelle/HOL. The analysis uses a given database to prove formal properties of our implemented functions with computer support. The main task in designing a practical formalization of correctness as well as efficient computer proofs of security properties is to cope with the complexity of cryptographic proving. We reduce this complexity by exploring a light-weight formalization that enables both appropriate formal definitions as well as efficient formal proofs. Consequently, we get reliable proofs with a minimal error rate augmenting the used database, what provides a formal basis for more computer proof constructions in this area.
Abstract: In present work are considered the scheme of
evaluation the transition probability in quantum system. It is based on
path integral representation of transition probability amplitude and its
evaluation by means of a saddle point method, applied to the part of
integration variables. The whole integration process is reduced to
initial value problem solutions of Hamilton equations with a random
initial phase point. The scheme is related to the semiclassical initial
value representation approaches using great number of trajectories. In
contrast to them from total set of generated phase paths only one path
for each initial coordinate value is selected in Monte Karlo process.
Abstract: This study aims to examine the factors affecting
knowledge sharing behavior in knowledge-based electronic communities (e-communities) because quantity and quality of
knowledge shared among the members play a critical role in the community-s sustainability. Past research has suggested three
perspectives that may affect the quantity and quality of knowledge
shared: economics, social psychology, and social ecology. In this
study, we strongly believe that an economic perspective may be suitable to validate factors influencing newly registered members-
knowledge contribution at the beginning of relationship development.
Accordingly, this study proposes a model to validate the factors influencing members- knowledge sharing based on Transaction Cost
Theory. By doing so, we may empirically test our hypotheses in various types of e-communities to determine the generalizability of our research models.
Abstract: The growing importance of sustainability in corporate
policies represents a great opportunity for workers to gain more
consideration, with great benefits to their well being. Sustainable
work is believed to be one which improves the organization-s
performance and fosters professional development as well as
workers- health. In a multiple case study based on document
research, information was sought about work activities and their
sustainability or corporate social responsibility (CSR) policies, as
disseminated by corporations. All the companies devoted attention to
work activities and delivered a good amount of information about
them. Nevertheless, the information presented was generic; all the
actions developed were top-down and there was no information about
the impact of changes aimed at sustainability on the workers-
activities. It was found that the companies seemed to be at an early
stage. In the future, they need to show more commitment through
concrete goals: they must be aware that workers contribute directly to
the corporations- sustainability. This would allow room for
Ergonomics and Work Psychodynamics to be incorporated and to be
useful for both companies and society, so as to promote and ensure
work sustainability.