Abstract: Environmental performance of the U.S. States is investigated for the period of 1990 – 2007 using Stochastic Frontier Analysis (SFA). The SFA accounts for both efficiency measure and stochastic noise affecting a frontier. The frontier is formed using indicators of GDP, energy consumption, population, and CO2 emissions. For comparability, all indicators are expressed as ratios to total. Statistical information of the Energy Information Agency of the United States is used. Obtained results reveal the bell - shaped dynamics of environmental efficiency scores. The average efficiency scores rise from 97.6% in 1990 to 99.6% in 1999, and then fall to 98.4% in 2007. The main factor is insufficient decrease in the rate of growth of CO2 emissions with regards to the growth of GDP, population and energy consumption. Data for 2008 following the research period allow for an assumption that the environmental performance of the U.S. States has improved in the last years.
Abstract: Cybercrime is now becoming a big challenge in Nigeria apart from the traditional crime. Inability to identify perpetrators is one of the reasons for the growing menace. This paper proposes a design for monitoring internet users’ activities in order to curbing cybercrime. It requires redefining the operations of Internet Service Providers (ISPs) which will now mandate users to be authenticated before accessing the internet. In implementing this work which can be adapted to a larger scale, a virtual router application is developed and configured to mimic a real router device. A sign-up portal is developed to allow users to register with the ISP. The portal asks for identification information which will include bio-data and government issued identification data like National Identity Card number, et cetera. A unique username and password are chosen by the user to enable access to the internet which will be used to reference him to an Internet Protocol Address (IP Address) of any system he uses on the internet and thereby associating him to any criminal act related to that IP address at that particular time. Questions such as “What happen when another user knows the password and uses it to commit crime?” and other pertinent issues are addressed.
Abstract: In this paper, we argue the security protocols of
ZigBee wireless sensor network in MAC layer. AES 128-bit
encryption algorithm in CCM* mode is secure transferred data;
however, AES-s secret key will be break within nearest future.
Efficient public key algorithm, ECC has been mixed with AES to
rescue the ZigBee wireless sensor from cipher text and replay attack.
Also, the proposed protocol can parallelize the integrity function to
increase system performance.
Abstract: Internal controls of accounting are an essential
business function for a growth-oriented organization, and include the
elements of risk assessment, information communications and even
employees' roles and responsibilities. Internal controls of accounting
systems are designed to protect a company from fraud, abuse and
inaccurate data recording and help organizations keep track of
essential financial activities. Internal controls of accounting provide a
streamlined solution for organizing all accounting procedures and
ensuring that the accounting cycle is completed consistently and
successfully. Implementing a formal Accounting Procedures Manual
for the organization allows the financial department to facilitate
several processes and maintain rigorous standards. Internal controls
also allow organizations to keep detailed records, manage and
organize important financial transactions and set a high standard for
the organization's financial management structure and protocols. A
well-implemented system also reduces the risk of accounting errors
and abuse. A well-implemented controls system allows a company's
financial managers to regulate and streamline all functions of the
accounting department. Internal controls of accounting can be set up
for every area to track deposits, monitor check handling, keep track
of creditor accounts, and even assess budgets and financial statements
on an ongoing basis. Setting up an effective accounting system to
monitor accounting reports, analyze records and protect sensitive
financial information also can help a company set clear goals and
make accurate projections. Creating efficient accounting processes
allows an organization to set specific policies and protocols on
accounting procedures, and reach its financial objectives on a regular
basis. Internal accounting controls can help keep track of such areas
as cash-receipt recording, payroll management, appropriate recording
of grants and gifts, cash disbursements by authorized personnel, and
the recording of assets. These systems also can take into account any
government regulations and requirements for financial reporting.
Abstract: Salinity level may affect early development of
biofuel feedstock crops. The biofuel feedstock crops canola
(Brassica napus L.), sorghum [Sorghum bicolor (L.) Moench], and
sunflower (Helianthus annuus L.); and the potential feedstock crop
sweet corn (Zea mays L.) were planted in media in pots and treated
with aqueous solutions of 0, 0.1, 0.5 and 1.0 M NaCl once at: 1)
planting; 2) 7-10 days after planting or 3) first true leaf expansion.
An additional treatment (4) comprised of one-half strength of the 0.1,
0.5 and 1.0 M (concentrations 0.05, 0.25, 0.5 M at each application)
was applied at first true leaf expansion and four days later. Survival
of most crops decreased below 90% above 0.5 M; survival of canola
decreased above 0.1 M. Application timing had little effect on crop
survival. For canola root fresh and dry weights improved when
application was at plant emergence; for sorghum top and root fresh
weights improved when the split application was used. When
application was at planting root dry weight was improved over most
other applications. Sunflower top fresh weight was among the
highest when saline solutions were split and top dry weight was
among the highest when application was at plant emergence. Sweet
corn root fresh weight was improved when the split application was
used or application was at planting. Sweet corn root dry weight was
highest when application was at planting or plant emergence. Even at
high salinity rates survival rates greater than what might be expected
occurred. Plants that survived appear to be able to adjust to saline
during the early stages of development.
Abstract: In this paper we discuss the effect of unbounded particle interaction operator on particle growth and we study how this can address the choice of appropriate time steps of the numerical simulation. We provide also rigorous mathematical proofs showing that large particles become dominating with increasing time while small particles contribute negligibly. Second, we discuss the efficiency of the algorithm by performing numerical simulations tests and by comparing the simulated solutions with some known analytic solutions to the Smoluchowski equation.
Abstract: Transmission control protocol (TCP) Vegas detects
network congestion in the early stage and successfully prevents
periodic packet loss that usually occurs in TCP Reno. It has been
demonstrated that TCP Vegas outperforms TCP Reno in many
aspects. However, TCP Vegas suffers several problems that affect its
congestion avoidance mechanism. One of the most important
weaknesses in TCP Vegas is that alpha and beta depend on a good
expected throughput estimate, which as we have seen, depends on a
good minimum RTT estimate. In order to make the system more
robust alpha and beta must be made responsive to network conditions
(they are currently chosen statically). This paper proposes a modified
Vegas algorithm, which can be adjusted to present good performance
compared to other transmission control protocols (TCPs). In order to
do this, we use PSO algorithm to tune alpha and beta. The simulation
results validate the advantages of the proposed algorithm in term of
performance.
Abstract: The objective of current issue was to develop a model
of testicular herpes simplex virus (HSV) type I infection for
assessment of viral effect on fertility. 56 male mice were inoculated
intraperitoneally with different concentrations of HSV on 8 day post
partum. It was revealed that the optimal dose was 100 plaque
forming units per mice as it provided testicular infection in 100% of
survivors. HSV proteins were detected both in somatic and germ
cells (spermatogonia, spermatocytes, spermatides). Although DNA
load in testis was descending from 3 to 28 days post infection only
12.5% of infected males had offspring after mating with uninfected
females comparing to 87.5% in control (p=0.012). These results are
the first direct evidence for HSV impact in male sterility. Prepuberal
mice appeared to be a suitable model for investigation of
pathogenesis of virus-associated fertility disorders.
Abstract: For decades financial economists have been attempted to determine the optimal investment policy by recognizing the option value embedded in irreversible investment whose project value evolves as a geometric Brownian motion (GBM). This paper aims to examine the effects of the optimal investment trigger and of the misspecification of stochastic processes on investment in real options applications. Specifically, the former explores the consequence of adopting optimal investment rules on the distributions of corporate value under the correct assumption of stochastic process while the latter analyzes the influence on the distributions of corporate value as a result of the misspecification of stochastic processes, i.e., mistaking an alternative process as a GBM. It is found that adopting the correct optimal investment policy may increase corporate value by shifting the value distribution rightward, and the misspecification effect may decrease corporate value by shifting the value distribution leftward. The adoption of the optimal investment trigger has a major impact on investment to such an extent that the downside risk of investment is truncated at the project value of zero, thereby moving the value distributions rightward. The analytical framework is also extended to situations where collection lags are in place, and the result indicates that collection lags reduce the effects of investment trigger and misspecification on investment in an opposite way.
Abstract: Hydrogen is regarded to play an important role in
future energy systems because it can be produced from abundant
resources and its combustion only generates water. The disposal of
waste tyres is a major problem in environmental management
throughout the world. The use of waste materials as a source of
hydrogen is particularly of interest in that it would also solve a waste
treatment problem. There is much interest in the use of alternative
feedstocks for the production of hydrogen since more than 95% of
current production is from fossil fuels. The pyrolysis of waste tyres
for the production of liquid fuels, activated carbons and gases has
been extensively researched. However, combining pyrolysis with
gasification is a novel process that can gasify the gaseous products
from pyrolysis. In this paper, an experimental investigation into the
production of hydrogen and other gases from the bench scale
pyrolysis-gasification of tyres has been investigated. Experiments
were carried using a two stage system consisting of pyrolysis of the
waste tyres followed by catalytic steam gasification of the evolved
gases and vapours in a second reactor. Experiments were conducted
at a pyrolysis temperature of 500 °C using Ni/Al2O3 as a catalyst. The
results showed that there was a dramatic increase in gas yield and the
potential H2 production when the gasification temperature was
increased from 600 to 900 oC. Overall, the process showed that high
yields of hydrogen can be produced from waste tyres.
Abstract: In cognitive radio (CR) systems, the primary user (PU) signal would randomly depart or arrive during the sensing period of a CR user, which is referred to as the high traffic environment. In this paper, we propose a novel spectrum sensing scheme based
on the cyclostationarity of PU signals in high traffic environments. Specifically, we obtain a test statistic by applying an estimate of spectral autocoherence function of the PU signal to the generalized- likelihood ratio. From numerical results, it is confirmed that the proposed scheme provides a better spectrum sensing performance compared with the conventional spectrum sensing scheme based on the energy of the PU signals in high traffic environments.
Abstract: The interrelationship between international stock
markets has been a key study area among the financial market
researchers for international portfolio management and risk
measurement. The characteristics of security returns and their
dynamics play a vital role in the financial market theory. This study
is an attempt to find out the dynamic linkages among the equity
market of USA and emerging markets of Pakistan and India using
daily data covering the period of January 2003–December 2009. The
study utilizes Johansen (Journal of Economic Dynamics and Control,
12, 1988) and Johansen and Juselius (Oxford Bulletin of Economics
and Statistics, 52, 1990) cointegration procedure for long run
relationship and Granger-causality tests based on Toda and
Yamamoto (Journal of Econometrics, 66, 1995) methodology.
No cointegration was found among stock markets of USA, Pakistan
and India, while Granger-causality test showed the evidence of
unidirectional causality running from New York stock exchange to
Bombay and Karachi stock exchanges.
Abstract: A finite element analysis was conducted to determine
the effect of moisture diffusion and hygroscopic swelling in rice. A
parallel simple stochastic modeling was performed to predict the
number of grains cracked as a result of moisture absorption and
hygroscopic swelling. Rice grains were soaked in thermally (25 oC)
controlled water and then tested for compressive stress. The
destructive compressive stress tests revealed through compressive
stress calculation that the peak force required to cause cracking in
grains soaked in water reduced with time as soaking duration was
extended. Results of the experiment showed that several grains had
their value of the predicted compressive stress below the von Mises
stress and were interpreted as grains which become cracked and/or
broke during soaking. The technique developed in this experiment
will facilitate the approximation of the number of grains which will
crack during soaking.
Abstract: The main idea behind in network aggregation is that,
rather than sending individual data items from sensors to sinks,
multiple data items are aggregated as they are forwarded by the
sensor network. Existing sensor network data aggregation techniques
assume that the nodes are preprogrammed and send data to a central
sink for offline querying and analysis. This approach faces two major
drawbacks. First, the system behavior is preprogrammed and cannot
be modified on the fly. Second, the increased energy wastage due to
the communication overhead will result in decreasing the overall
system lifetime. Thus, energy conservation is of prime consideration
in sensor network protocols in order to maximize the network-s
operational lifetime. In this paper, we give an energy efficient
approach to query processing by implementing new optimization
techniques applied to in-network aggregation. We first discuss earlier
approaches in sensors data management and highlight their
disadvantages. We then present our approach “Energy Efficient
Indexed Aggregation" (EEIA) and evaluate it through several
simulations to prove its efficiency, competence and effectiveness.
Abstract: The current practice of determination of moisture diffusivity of building materials under laboratory conditions is predominantly aimed at the absorption phase. The main reason is the simplicity of the inverse analysis of measured moisture profiles. However, the liquid moisture transport may exhibit significant hysteresis. Thus, the moisture diffusivity should be different in the absorption (wetting) and desorption (drying) phase. In order to bring computer simulations of hygrothermal performance of building materials closer to the reality, it is then necessary to find new methods for inverse analysis which could be used in the desorption phase as well. In this paper we present genetic algorithm as a possible method of solution of the inverse problem of moisture transport in desorption phase. Its application is demonstrated for AAC as a typical building material.
Abstract: Automatic tube current modulation (ATCM) systems are available for all CT manufacturers and are used for the majority of patients. Understanding how the systems work and their influence on patient dose and image quality is important for CT users, in order to gain the most effective use of the systems. In the present study, a new phantom was used for evaluating dose distribution and image quality under the ATCM operation for the Toshiba Aquilion 64 CT scanner using different ATCM options and a fixed mAs technique. A routine chest, abdomen and pelvis (CAP) protocol was selected for study and Gafchromic film was used to measure entrance surface dose (ESD), peripheral dose and central axis dose in the phantom. The results show the dose reductions achievable with various ATCM options, in relation with the target noise. The doses and image noise distribution were more uniform when the ATCM system was implemented compared with the fixed mAs technique. The lower limit set for the tube current will affect the modulations especially for the lower dose option. This limit prevented the tube current being reduced further and therefore the lower dose ATCM setting resembled a fixed mAs technique. Selection of a lower tube current limit is likely to reduce doses for smaller patients in scans of chest and neck regions.
Abstract: This study aimed at developing a forecasting model on the number of Dengue Haemorrhagic Fever (DHF) incidence in Northern Thailand using time series analysis. We developed Seasonal Autoregressive Integrated Moving Average (SARIMA) models on the data collected between 2003-2006 and then validated the models using the data collected between January-September 2007. The results showed that the regressive forecast curves were consistent with the pattern of actual values. The most suitable model was the SARIMA(2,0,1)(0,2,0)12 model with a Akaike Information Criterion (AIC) of 12.2931 and a Mean Absolute Percent Error (MAPE) of 8.91713. The SARIMA(2,0,1)(0,2,0)12 model fitting was adequate for the data with the Portmanteau statistic Q20 = 8.98644 ( x20,95= 27.5871, P>0.05). This indicated that there was no significant autocorrelation between residuals at different lag times in the SARIMA(2,0,1)(0,2,0)12 model.
Abstract: To maximise furnace production it-s necessary to
optimise furnace control, with the objectives of achieving maximum
power input into the melting process, minimum network distortion
and power-off time, without compromise on quality and safety. This
can be achieved with on the one hand by an appropriate electrode
control and on the other hand by a minimum of AC transformer
switching.
Electrical arc is a stochastic process; witch is the principal cause
of power quality problems, including voltages dips, harmonic
distortion, unbalance loads and flicker. So it is difficult to make an
appropriate model for an Electrical Arc Furnace (EAF). The factors
that effect EAF operation are the melting or refining materials,
melting stage, electrode position (arc length), electrode arm control
and short circuit power of the feeder. So arc voltages, current and
power are defined as a nonlinear function of the arc length. In this
article we propose our own empirical function of the EAF and model,
for the mean stages of the melting process, thanks to the
measurements in the steel factory.
Abstract: Today modern simulations solutions in the wind turbine industry have achieved a high degree of complexity and detail in result. Limitations exist when it is time to validate model results against measurements. Regarding Model validation it is of special interest to identify mode frequencies and to differentiate them from the different excitations. A wind turbine is a complex device and measurements regarding any part of the assembly show a lot of noise. Input excitations are difficult or even impossible to measure due to the stochastic nature of the environment. Traditional techniques for frequency analysis or features extraction are widely used to analyze wind turbine sensor signals, but have several limitations specially attending to non stationary signals (Events). A new technique based on autoregresive analysis techniques is introduced here for a specific application, a comparison and examples related to different events in the wind turbine operations are presented.
Abstract: Electronic seal is an electronic device to check the
authenticity and integrity of freight containers at the point of arrival.
While RFID-based eSeals are gaining more acceptances and there are
also some standardization processes for these devices, a recent
research revealed that the current RFID-based eSeals are vulnerable to
various attacks. In this paper, we provide a feasible solution to
enhance the security of active RFID-based eSeals. Our approach is to
use an authentication and key agreement protocol between eSeal and
reader device, enabling data encryption and integrity check. Our
protocol is based on the use of block cipher AES, which is reasonable
since a block cipher can also be used for many other security purposes
including data encryption and pseudo-random number generation. Our
protocol is very simple, and it is applicable to low-end active RFID
eSeals.