Abstract: Colored Petri Nets (CPN) are very known kind of
high level Petri nets. With sound and complete semantics, rewriting
logic is one of very powerful logics in description and verification of
non-deterministic concurrent systems. Recently, CPN semantics are
defined in terms of rewriting logic, allowing us to built models by
formal reasoning. In this paper, we propose an automatic translation
of CPN to the rewriting logic language Maude. This tool allows
graphical editing and simulating CPN. The tool allows the user
drawing a CPN graphically and automatic translating the graphical
representation of the drawn CPN to Maude specification. Then,
Maude language is used to perform the simulation of the resulted
Maude specification. It is the first rewriting logic based environment
for this category of Petri Nets.
Abstract: Wide applicability of concurrent programming
practices in developing various software applications leads to
different concurrency errors amongst which data race is the most
important. Java provides greatest support for concurrent
programming by introducing various concurrency packages. Aspect
oriented programming (AOP) is modern programming paradigm
facilitating the runtime interception of events of interest and can be
effectively used to handle the concurrency problems. AspectJ being
an aspect oriented extension to java facilitates the application of
concepts of AOP for data race detection. Volatile variables are
usually considered thread safe, but they can become the possible
candidates of data races if non-atomic operations are performed
concurrently upon them. Various data race detection algorithms have
been proposed in the past but this issue of volatility and atomicity is
still unaddressed. The aim of this research is to propose some
suggestions for incorporating certain conditions for data race
detection in java programs at the volatile fields by taking into account
support for atomicity in java concurrency packages and making use
of pointcuts. Two simple test programs will demonstrate the results
of research. The results are verified on two different Java
Development Kits (JDKs) for the purpose of comparison.
Abstract: Fuzzy sets theory affirmed that the linguistic value for
every contraries relation is complementary. It was stressed in the
intuitionistic fuzzy sets (IFS) that the conditions for contraries
relations, which are the fuzzy values, cannot be greater than one.
However, complementary in two contradict phenomena are not
always true. This paper proposes a new idea condition for conflicting
bifuzzy sets by relaxing the condition of intuitionistic fuzzy sets.
Here, we will critically forward examples using triangular fuzzy
number in formulating a new condition for conflicting bifuzzy sets
(CBFS). Evaluation of positive and negative in conflicting
phenomena were calculated concurrently by relaxing the condition in
IFS. The hypothetical illustration showed the applicability of the new
condition in CBFS for solving non-complement contraries
intuitionistic evaluation. This approach can be applied to any
decision making where conflicting is very much exist.
Abstract: This paper proposes a power-controlled scheduling scheme for devices using a directional antenna in smart home. In the case of the home network using directional antenna, devices can concurrently transmit data in the same frequency band. Accordingly, the throughput increases compared to that of devices using omni-directional antenna in proportional to the number of concurrent transmissions. Also, the number of concurrent transmissions depends on the beamwidth of antenna, the number of devices operating in the network , transmission power, interference and so on. In particular, the less transmission power is used, the more concurrent transmissions occur due to small transmission range. In this paper, we considered sub-optimal scheduling scheme for throughput maximization and power consumption minimization. In the scheme, each device is equipped with a directional antenna. Various beamwidths, path loss components, and antenna radiation efficiencies are considered. Numerical results show that the proposed schemes outperform the scheduling scheme using directional antennas without power control.
Abstract: In mobile environments, unspecified numbers of transactions
arrive in continuous streams. To prove correctness of their
concurrent execution a method of modelling an infinite number of
transactions is needed. Standard database techniques model fixed
finite schedules of transactions. Lately, techniques based on temporal
logic have been proposed as suitable for modelling infinite schedules.
The drawback of these techniques is that proving the basic
serializability correctness condition is impractical, as encoding (the
absence of) conflict cyclicity within large sets of transactions results
in prohibitively large temporal logic formulae. In this paper, we show
that, under certain common assumptions on the graph structure of
data items accessed by the transactions, conflict cyclicity need only
be checked within all possible pairs of transactions. This results in
formulae of considerably reduced size in any temporal-logic-based
approach to proving serializability, and scales to arbitrary numbers
of transactions.
Abstract: CScheme, a concurrent programming paradigm based
on scheme concept enables concurrency schemes to be constructed
from smaller synchronization units through a GUI based composer
and latter be reused on other concurrency problems of a similar
nature. This paradigm is particularly important in the multi-core
environment prevalent nowadays. In this paper, we demonstrate
techniques to separate concurrency from functional code using the
CScheme paradigm. Then we illustrate how the CScheme
methodology can be used to solve some of the traditional
concurrency problems – critical section problem, and readers-writers
problem - using synchronization schemes such as Single Threaded
Execution Scheme, and Readers Writers Scheme.
Abstract: The concurrent era is characterised by strengthened interactions among financial markets and increased capital mobility globally. In this frames we examine the effects the international financial integration process has on the European bond markets. We perform a comparative study of the interactions of the European and international bond markets and exploit Cointegration analysis results on the elimination of stochastic trends and the decomposition of the underlying long run equilibria and short run causal relations. Our investigation provides evidence on the relation between the European integration process and that of globalisation, viewed through the bond markets- sector. Additionally the structural formulation applied, offers significant implications of the findings. All in all our analysis offers a number of answers on crucial queries towards the European bond markets integration process.
Abstract: One major difficulty that faces developers of
concurrent and distributed software is analysis for concurrency based
faults like deadlocks. Petri nets are used extensively in the
verification of correctness of concurrent programs. ECATNets are a
category of algebraic Petri nets based on a sound combination of
algebraic abstract types and high-level Petri nets. ECATNets have
'sound' and 'complete' semantics because of their integration in
rewriting logic and its programming language Maude. Rewriting
logic is considered as one of very powerful logics in terms of
description, verification and programming of concurrent systems We
proposed previously a method for translating Ada-95 tasking
programs to ECATNets formalism (Ada-ECATNet) and we showed
that ECATNets formalism provides a more compact translation for
Ada programs compared to the other approaches based on simple
Petri nets or Colored Petri nets. We showed also previously how the
ECATNet formalism offers to Ada many validation and verification
tools like simulation, Model Checking, accessibility analysis and
static analysis. In this paper, we describe the implementation of our
translation of the Ada programs into ECATNets.
Abstract: The group mutual exclusion (GME) problem is an
interesting generalization of the mutual exclusion problem. Several
solutions of the GME problem have been proposed for message
passing distributed systems. However, none of these solutions is
suitable for real time distributed systems. In this paper, we propose a
token-based distributed algorithms for the GME problem in soft real
time distributed systems. The algorithm uses the concepts of priority
queue, dynamic request set and the process state. The algorithm uses
first come first serve approach in selecting the next session type
between the same priority levels and satisfies the concurrent
occupancy property. The algorithm allows all n processors to be
inside their CS provided they request for the same session. The
performance analysis and correctness proof of the algorithm has also
been included in the paper.
Abstract: A subjectively influenced router for vehicles in a fourjunction
traffic system is presented. The router is based on a 3-layer
Backpropagation Neural Network (BPNN) and a greedy routing
procedure. The BPNN detects priorities of vehicles based on the
subjective criteria. The subjective criteria and the routing procedure
depend on the routing plan towards vehicles depending on the user.
The routing procedure selects vehicles from their junctions based on
their priorities and route them concurrently to the traffic system. That
is, when the router is provided with a desired vehicles selection
criteria and routing procedure, it routes vehicles with a reasonable
junction clearing time. The cost evaluation of the router determines
its efficiency. In the case of a routing conflict, the router will route
the vehicles in a consecutive order and quarantine faulty vehicles.
The simulations presented indicate that the presented approach is an
effective strategy of structuring a subjective vehicle router.
Abstract: According to the governmental data, the cases of oral
cancers doubled in the past 10 years. This had brought heavy burden to
the patients- family, the society, and the country. The literature
generally evidenced the betel nut contained particular chemicals that
can cause oral cancers. Research in Taiwan had also proofed that 90
percent of oral cancer patients had experience of betel nut chewing. It
is thus important to educate the betel-nut hobbyists to cease such a
hazardous behavior. A program was then organized to establish
several training classes across different areas specific to help ceasing
this particular habit. Purpose of this research was to explore the
attitude and intention toward ceasing betel-nut chewing before and
after attending the training classes. 50 samples were taken from a
ceasing class with average age at 45 years old with high school
education (54%). 74% of the respondents were male in service or
agricultural industries. Experiences in betel-nut chewing were 5-20
years with a dose of 1-20 pieces per day. The data had shown that 60%
of the respondents had cigarette smoking habit, and 30% of the
respondents were concurrently alcoholic dependent. Research results
indicated that the attitude, intentions, and the knowledge on oral
cancers were found significant different between before and after
attendance. This provided evidence for the effectiveness of the training
class. However, we do not perform follow-up after the class.
Noteworthy is the test result also shown that participants who were
drivers as occupation, or habitual smokers or alcoholic dependents
would be less willing to quit the betel-nut chewing. The test results
indicated as well that the educational levels and the type of occupation
may have significant impacts on an individual-s decisions in taking
betel-nut or substance abuse.
Abstract: Parallel programming models exist as an abstraction
of hardware and memory architectures. There are several parallel
programming models in commonly use; they are shared memory
model, thread model, message passing model, data parallel model,
hybrid model, Flynn-s models, embarrassingly parallel computations
model, pipelined computations model. These models are not specific
to a particular type of machine or memory architecture. This paper
expresses the model program for concurrent approach to data parallel
model through java programming.
Abstract: The inherent iterative nature of product design and development poses significant challenge to reduce the product design and development time (PD). In order to shorten the time to market, organizations have adopted concurrent development where multiple specialized tasks and design activities are carried out in parallel. Iterative nature of work coupled with the overlap of activities can result in unpredictable time to completion and significant rework. Many of the products have missed the time to market window due to unanticipated or rather unplanned iteration and rework. The iterative and often overlapped processes introduce greater amounts of ambiguity in design and development, where the traditional methods and tools of project management provide less value. In this context, identifying critical metrics to understand the iteration probability is an open research area where significant contribution can be made given that iteration has been the key driver of cost and schedule risk in PD projects. Two important questions that the proposed study attempts to address are: Can we predict and identify the number of iterations in a product development flow? Can we provide managerial insights for a better control over iteration? The proposal introduces the concept of decision points and using this concept intends to develop metrics that can provide managerial insights into iteration predictability. By characterizing the product development flow as a network of decision points, the proposed research intends to delve further into iteration probability and attempts to provide more clarity.
Abstract: The scientific community has invested a great deal of effort in the fields of discrete wavelet transform in the last few decades. Discrete wavelet transform (DWT) associated with the vector quantization has been proved to be a very useful tool for the compression of image. However, the DWT is very computationally intensive process requiring innovative and computationally efficient method to obtain the image compression. The concurrent transformation of the image can be an important solution to this problem. This paper proposes a model of concurrent DWT for image compression. Additionally, the formal verification of the model has also been performed. Here the Symbolic Model Verifier (SMV) has been used as the formal verification tool. The system has been modeled in SMV and some properties have been verified formally.
Abstract: Due to important issues, such as deadlock, starvation,
communication, non-deterministic behavior and synchronization,
concurrent systems are very complex, sensitive, and error-prone.
Thus ensuring reliability and accuracy of these systems is very
essential. Therefore, there has been a big interest in the formal
specification of concurrent programs in recent years. Nevertheless,
some features of concurrent systems, such as dynamic process
creation, scheduling and starvation have not been specified formally
yet. Also, some other features have been specified partially and/or
have been described using a combination of several different
formalisms and methods whose integration needs too much effort. In
other words, a comprehensive and integrated specification that could
cover all aspects of concurrent systems has not been provided yet.
Thus, this paper makes two major contributions: firstly, it provides a
comprehensive formal framework to specify all well-known features
of concurrent systems. Secondly, it provides an integrated
specification of these features by using just a single formal notation,
i.e., the Z language.
Abstract: We present an operator for a propositional linear temporal logic over infinite schedules of iterated transactions, which, when applied to a formula, asserts that any schedule satisfying the formula is serializable. The resulting logic is suitable for specifying and verifying consistency properties of concurrent transaction management systems, that can be defined in terms of serializability, as well as other general safety and liveness properties. A strict form of serializability is used requiring that, whenever the read and write steps of a transaction occurrence precede the read and write steps of another transaction occurrence in a schedule, the first transaction must precede the second transaction in an equivalent serial schedule. This work improves on previous work in providing a propositional temporal logic with a serializability operator that is of the same PSPACE complete computational complexity as standard propositional linear temporal logic without a serializability operator.
Abstract: In this paper, supply policy and procurement of
shared resources in some kinds of concurrent construction projects
are investigated. This could be oriented to the problems of holding
construction companies who involve in different projects
concurrently and they have to supply limited resources to several
projects as well as prevent delays to any project. Limits on
transportation vehicles and storage facilities for potential
construction materials and also the available resources (such as cash
or manpower) are some of the examples which affect considerably on
management of all projects over all. The research includes
investigation of some real multi-storey buildings during their
execution periods and surveying the history of the activities. It is
shown that the common resource demand variation curve of the
projects may be expanded or displaced to achieve an optimum
distribution scheme. Of course, it may cause some delay to some
projects, but it has minimum influence on whole execution period of
all projects and its influence on procurement cost of the projects is
considerable. These observations on investigation of some
multistorey building which are built in Iran will be presented in this
paper.
Abstract: Design should be viewed concurrently by three ways
as transformation, flow and value generation. An innovative approach
to solve design – related problems is described as the integrated
product - process design. As a foundation for a formal framework
consisting of organizing principles and techniques, Work Structuring
has been developed to guide efforts in the integration that enhances
the development of operation and process design in alignment with
product design.
Vietnam construction projects are facing many delays, and cost
overruns caused mostly by design related problems. A better design
management that integrates product and process design could resolve
these problems. A questionnaire survey and in – depth interviews
were used to investigate the feasibility of applying Work Structuring
to construction projects in Vietnam.
The purpose of this paper is to present the research results and to
illustrate the possible problems and potential solutions when Work
Structuring is implemented to construction projects in Vietnam.
Abstract: The present paper reports the removal of Cd(II) and
Zn(II) ions using synthetic Zeolit NaA. The adsorption capacity of
the sorbent (Zeolite NaA) strongly depends on simultaneous or not
simultaneous (concurrent) presence of Cd(II) and Zn(II) in the
sorbate. When Cd(II) and Zn(II) are present simultaneously
(concurrently) in the sorbate, Zn(II) ions were sorbed at higher rate.
Equilibrium data fitted Langmuir, Freundlich and Tempkin isotherms
well. The applicability of the isotherm equation to describe the
adsorption process was judged by the correlation coefficients R2. The
Langmuir model yielded the best fit with R2 values equal to or higher
than 0.970, as compared to the Freundlich and Tempkin models. The
fact that 1/n values range from 0.322 to 0.755 indicates that the
adsorption of Cd(II) and Zn(II) ions from aqueous solutions also
favored by the Freundlich model.
Abstract: A new approach for timestamp ordering problem in
serializable schedules is presented. Since the number of users using
databases is increasing rapidly, the accuracy and needing high
throughput are main topics in database area. Strict 2PL does not
allow all possible serializable schedules and so does not result high
throughput. The main advantages of the approach are the ability to
enforce the execution of transaction to be recoverable and the high
achievable performance of concurrent execution in central databases.
Comparing to Strict 2PL, the general structure of the algorithm is
simple, free deadlock, and allows executing all possible serializable
schedules which results high throughput. Various examples which
include different orders of database operations are discussed.