Abstract: An optimal control problem for a mathematical model of efficiency of antiviral therapy in hepatitis B virus infections is considered. The aim of the study is to control the new viral production, block the new infection cells and maintain the number of uninfected cells in the given range. The optimal controls represent the efficiency of antiviral therapy in inhibiting viral production and preventing new infections. Defining the cost functional, the optimal control problem is converted into the constrained optimization problem and the first order optimality system is derived. For the numerical simulation, we propose the steepest descent algorithm based on the adjoint variable method. A computer program in MATLAB is developed for the numerical simulations.
Abstract: This paper deals with a periodic-review substitutable
inventory system for a finite and an infinite number of periods. Here
an upward substitution structure, a substitution of a more costly item
by a less costly one, is assumed, with two products. At the beginning
of each period, a stochastic demand comes for the first item only,
which is quality-wise better and hence costlier. Whenever an arriving
demand finds zero inventory of this product, a fraction of unsatisfied
customers goes for its substitutable second item. An optimal ordering
policy has been derived for each period. The results are illustrated
with numerical examples. A sensitivity analysis has been done to
examine how sensitive the optimal solution and the maximum profit
are to the values of the discount factor, when there is a large number
of periods.
Abstract: The six sigma method is a project-driven management approach to improve the organization-s products, services, and processes by continually reducing defects in the organization. Understanding the key features, obstacles, and shortcomings of the six sigma method allows organizations to better support their strategic directions, and increasing needs for coaching, mentoring, and training. It also provides opportunities to better implement six sigma projects. The purpose of this paper is the survey of six sigma process and its impact on the organizational productivity. So I have studied key concepts , problem solving process of six sigmaas well as the survey of important fields such as: DMAIC, six sigma and productivity applied programme, and other advantages of six sigma. In the end of this paper, present research conclusions. (direct and positive relation between six sigma and productivity)
Abstract: In the last decades to supply the various and different
demands of clients, a lot of manufacturers trend to use the mixedmodel
assembly line (MMAL) in their production lines, since this
policy make possible to assemble various and different models of the
equivalent goods on the same line with the MTO approach.
In this article, we determine the sequence of (MMAL) line, with
applying the kitting approach and planning of rest time for general
workers to reduce the wastages, increase the workers effectiveness
and apply the sector of lean production approach.
This Multi-objective sequencing problem solved in small size with
GAMS22.2 and PSO meta heuristic in 10 test problems and compare
their results together and conclude that their results are very similar
together, next we determine the important factors in computing the
cost, which improving them cost reduced. Since this problem, is NPhard
in large size, we use the particle swarm optimization (PSO)
meta-heuristic for solving it. In large size we define some test
problems to survey it-s performance and determine the important
factors in calculating the cost, that by change or improved them
production in minimum cost will be possible.
Abstract: The purpose of this research was develop a biological
nutrient removal (BNR) system which has low energy consumption, sludge production, and land usage. These indicate that BNR system could be a alternative of future wastewater treatment in ubiquitous
city(U-city). Organics and nitrogen compounds could be removed by this system so that secondary or tertiary stages of wastewater treatment satisfy their standards. This system was composed of oxic and anoxic
filter filed with PVDC and POM media. Anoxic/oxic filter system operated under empty bed contact time of 4 hours by increasing
recirculation ratio from 0 to 100 %. The system removals of total nitrogen and COD were 76.3% and 93%, respectively. To be observed
internal behavior in this system SCOD, NH3-N, and NO3-N were
conducted and removal shows range of 25~100%, 59~99%, and
70~100%, respectively.
Abstract: A preliminary evaluation of the feasibility of installing small wind turbines on offshore oil and gas extraction platforms is presented. Some aerodynamic considerations are developed in order to determine the best rotor architecture to exploit the wind potential on such installations, assuming that wind conditions over the platforms are similar to those registered on the roofs of urban buildings. Economical considerations about both advantages and disadvantages of the exploitation of wind energy on offshore extraction platforms with respect to conventional offshore wind plants, is also presented. Finally, wind charts of European offshore winds are presented together with a map of the major offshore installations.
Abstract: Growing world population has fundamental impacts
and often catastrophic on natural habitat. The immethodical
consumption of energy, destruction of the forests and extinction of
plant and animal species are the consequence of this experience.
Urban sustainability and sustainable urban development, that is so
spoken these days, should be considered as a strategy, goal and
policy, beyond just considering environmental issues and protection.
The desert-s climate has made a bunch of problems for its residents.
Very hot and dry climate in summers of the Iranian desert areas,
when there was no access to modern energy source and mechanical
cooling systems in the past, made Iranian architects to design a
natural ventilation system in their buildings. The structure, like a
tower going upward the roof, besides its ornamental application and
giving a beautiful view to the building, was used as a spontaneous
ventilation system. In this paper, it has been tried to name the
problems of the area and it-s inconvenience, then some answers has
pointed out in order to solve the problems and as an alternative
solution BADGIR (wind-catcher) has been introduced as a solution
knowing that it has been playing a major role in dealing with the
problems.
Abstract: Among the chemicals used for ammunition production, TNT (Trinitrotoluene) play a significant role since World War I and II. Various types of military weapon utilize TNT in casting process. However, the TNT casting process for warhead is difficult to control the cooling rate of the liquid TNT. This problem occurs because the casting process lacks the equipment to detect the temperature during the casting procedure This study presents the temperature detected by infrared camera to illustrate the cooling rate and cooling zone of curing, and demonstrates the optimization of TNT condition to reduce the risk of air gap occurred in the warhead which can result in the destruction afterward. Premature initiation of explosive-filled projectiles in response to set-back forces during gunfiring cause by casting defects. Finally the study can help improving the process of the TNT casting. The operators can control the curing of TNT inside the case by rising up the heating rod at the proper time. Consequently this can reduce tremendous time of rework if the air gaps occur and increase strength to lower elastic modulus. Therefore, it can be clearly concluded that the use of Infrared Cameras in this process is another method to improve the casting procedure.
Abstract: The nature of consumer products causes the difficulty
in forecasting the future demands and the accuracy of the forecasts
significantly affects the overall performance of the supply chain
system. In this study, two data mining methods, artificial neural
network (ANN) and support vector machine (SVM), were utilized to
predict the demand of consumer products. The training data used was
the actual demand of six different products from a consumer product
company in Thailand. The results indicated that SVM had a better
forecast quality (in term of MAPE) than ANN in every category of
products. Moreover, another important finding was the margin
difference of MAPE from these two methods was significantly high
when the data was highly correlated.
Abstract: Classifier fusion may generate more accurate
classification than each of the basic classifiers. Fusion is often based
on fixed combination rules like the product, average etc. This paper
presents decision templates as classifier fusion method for the
recognition of the handwritten English and Farsi numerals (1-9).
The process involves extracting a feature vector on well-known
image databases. The extracted feature vector is fed to multiple
classifier fusion. A set of experiments were conducted to compare
decision templates (DTs) with some combination rules. Results from
decision templates conclude 97.99% and 97.28% for Farsi and
English handwritten digits.
Abstract: International markets driven forces are changing
continuously, therefore companies need to gain a competitive edge in
such markets. Improving the company's products, processes and
practices is no longer auxiliary. Lean production is a production
management philosophy that consolidates work tasks with minimum
waste resulting in improved productivity. Lean production practices
can be mapped into many production areas. One of these is
Manufacturing Equipment and Technology (MET). Many lean
production practices can be implemented in MET, namely, specific
equipment configurations, total preventive maintenance, visual
control, new equipment/ technologies, production process
reengineering and shared vision of perfection.The purpose of this
paper is to investigate the implementation level of these six practices
in Jordanian industries. To achieve that a questionnaire survey has
been designed according to five-point Likert scale. The questionnaire
is validated through pilot study and through experts review. A sample
of 350 Jordanian companies were surveyed, the response rate was
83%. The respondents were asked to rate the extent of
implementation for each of practices. A relationship conceptual
model is developed, hypotheses are proposed, and consequently the
essential statistical analyses are then performed. An assessment tool
that enables management to monitor the progress and the
effectiveness of lean practices implementation is designed and
presented. Consequently, the results show that the average
implementation level of lean practices in MET is 77%, Jordanian
companies are implementing successfully the considered lean
production practices, and the presented model has Cronbach-s alpha
value of 0.87 which is good evidence on model consistency and
results validation.
Abstract: Biodiesel is traditionally produced from oleaginous
plants. On the other hand, increasing biodiesel production from these
raw materials could create problems of food supply. Producing
biodiesel from microalgae could help to overcome this difficulty,
because microalgae are rich in lipids and do not compete for arable
lands. However, no studies had compared vegetable and microalgae
oil-based biodiesel in terms of yield, viscosity and heat of
combustion. In the present study, commercial canola and microalgae
oil were therefore transesterified with methanol under a homogenous
alkali catalyst (potassium hydroxide) at 100oC for 1h. The result
showed that microalgae-based oil has a higher yield in biodiesel with
89.7% (g biodiesel/g oil) and a lower kinematic viscosity (22oC) of
4.31 mm/s2 than canola oil.
Abstract: Uncertainties of a serial production line affect on the
production throughput. The uncertainties cannot be prevented in a
real production line. However the uncertain conditions can be
controlled by a robust prediction model. Thus, a hybrid model
including autoregressive integrated moving average (ARIMA) and
multiple polynomial regression, is proposed to model the nonlinear
relationship of production uncertainties with throughput. The
uncertainties under consideration of this study are demand, breaktime,
scrap, and lead-time. The nonlinear relationship of production
uncertainties with throughput are examined in the form of quadratic
and cubic regression models, where the adjusted R-squared for
quadratic and cubic regressions was 98.3% and 98.2%. We optimized
the multiple quadratic regression (MQR) by considering the time
series trend of the uncertainties using ARIMA model. Finally the
hybrid model of ARIMA and MQR is formulated by better adjusted
R-squared, which is 98.9%.
Abstract: Maize and Indian mustard are significant crops in
semi-arid climate zones of India. Improved water management
requires precise scheduling of irrigation, which in turn requires an
accurate computation of daily crop evapotranspiration (ETc). Daily
crop evapotranspiration comes as a product of reference
evapotranspiration (ET0) and the growth stage specific crop
coefficients modified for daily variation. The first objective of
present study is to develop crop coefficients Kc for Maize and Indian
mustard. The estimated values of Kc for maize at the four crop
growth stages (initial, development, mid-season, and late season) are
0.55, 1.08, 1.25, and 0.75, respectively, and for Indian mustard the Kc
values at the four growth stages are 0.3, 0.6, 1.12, and 0.35,
respectively. The second objective of the study is to compute daily
crop evapotranspiration from ET0 and crop coefficients. Average
daily ETc of maize varied from about 2.5 mm/d in the early growing
period to > 6.5 mm/d at mid season. The peak ETc of maize is 8.3
mm/d and it occurred 64 days after sowing at the reproductive growth
stage when leaf area index was 4.54. In the case of Indian mustard,
average ETc is 1 mm/d at the initial stage, >1.8 mm/d at mid season
and achieves a peak value of 2.12 mm/d on 56 days after sowing.
Improved schedules of irrigation have been simulated based on daily
crop evapo-transpiration and field measured data. Simulation shows a
close match between modeled and field moisture status prevalent
during crop season.
Abstract: This paper presents a multi-objective order allocation
planning problem with the consideration of various real-world
production features. A novel hybrid intelligent optimization model,
integrating a multi-objective memetic optimization process, a Monte
Carlo simulation technique and a heuristic pruning technique, is
proposed to handle this problem. Experiments based on industrial data
are conducted to validate the proposed model. Results show that (1)
the proposed model can effectively solve the investigated problem by
providing effective production decision-making solutions, which
outperformsan NSGA-II-based optimization process and an industrial
method.
Abstract: The experiment was then conducted to investigate the
effect of cassava peel addition in the concentrate on the performance
of lactating dairy cows. Twenty four Holstein Friesian crossbred
(>87.5% Holstein Friesian) lactating dairy cows in mid lactation;
averaging 12.2+2.1 kg of milk, 119+45 days in milk, 44.1+6.2
months old and 449+33 kg live weight, were stratified for milk yield,
days in milk, age, stage of lactation and body weight, and then
randomly allocated to three treatment groups. The first, second and
third groups were fed concentrates containing the respective cassava
peel, 0, 20 and 40%. All cows were fed ad libitum corn silage and
freely access to clean water. Dry matter intake, 4%FCM, milk
composition and body weight change were affected (P
Abstract: This paper focuses on robust design and optimization
of industrial production wastes. Past literatures were reviewed to case
study Clamason Industries Limited (CIL) - a leading ladder-tops
manufacturer. A painstaking study of the firm-s practices at the shop
floor revealed that Over-production, Waiting time, Excess inventory,
and Defects are the major wastes that are impeding their progress and
profitability. Design expert8 software was used to apply Taguchi
robust design and response surface methodology in order to model,
analyse and optimise the wastes cost in CIL. Waiting time and overproduction
rank first and second in contributing to the costs of wastes
in CIL. For minimal wastes cost the control factors of overproduction,
waiting-time, defects and excess-inventory must be set at
0.30, 390.70, 4 and 55.70 respectively for CIL. The optimal value of
cost of wastes for the months studied was 22.3679. Finally, a
recommendation was made that for the company to enhance their
profitability and customer satisfaction, they must adopt the Shingeo
Shingo-s Single Minute Exchange of Dies (SMED), which will
immediately tackle the waste of waiting by drastically reducing their
setup time.
Abstract: Anaerobic treatment has many advantages over other
biological method particularly when used to treat complex
wastewater such as petroleum refinery wastewater. In this study two
Up-flow Anaerobic Sludge Blanket (UASB) reactors were operated
in parallel to treat six volumetric organic loads (0.58, 1.21, 0.89,
2.34, 1.47 and 4.14 kg COD/m3·d) to evaluate the chemical oxygen
demand (COD) removal efficiency. The reactors were continuously
adapting to the changing of operation condition with increase in the
removal efficiency or slight decrease until the last load which was
more than two times the load, at which the reactor stressed and the
removal efficiency decreased to 75% with effluent concentration of
1746 mg COD/L. Other parameters were also monitored such as pH,
alkalinity, volatile fatty acid and gas production rate. The UASB
reactor was suitable to treat petroleum refinery wastewater and the
highest COD removal rate was 83% at 1215 kg/m3·d with COD
concentration about 356 mg/L in the effluent.
Abstract: Dextran is a D-glucose polymer which is produced by
Leuconostoc mesenteroides grown in a sucrose-rich media. The
organism was obtained from the Persian Type Culture Collection
(PTCC) and was transferred in MRS broth medium at 30°C and pH
6.8 for 24 h. After preparation of inoculums, organisms were
inoculated into five liquid fermentation media containing either
molasses or cheese whey or different combinations of cheese whey
and molasses. After certain fermentation period, the produced
dextran was separated and dried. Dextran yield was calculated and
significant differences in different media were observed.
Furthermore, FT-IR analysis was performed and the results showed
that there were no significant differences in the produced dextran
structures.
Abstract: This paper proposes an innovative methodology for
Acceptance Sampling by Variables, which is a particular category of
Statistical Quality Control dealing with the assurance of products
quality. Our contribution lies in the exploitation of machine learning
techniques to address the complexity and remedy the drawbacks of
existing approaches. More specifically, the proposed methodology
exploits Artificial Neural Networks (ANNs) to aid decision making
about the acceptance or rejection of an inspected sample. For any
type of inspection, ANNs are trained by data from corresponding
tables of a standard-s sampling plan schemes. Once trained, ANNs
can give closed-form solutions for any acceptance quality level and
sample size, thus leading to an automation of the reading of the
sampling plan tables, without any need of compromise with the
values of the specific standard chosen each time. The proposed
methodology provides enough flexibility to quality control engineers
during the inspection of their samples, allowing the consideration of
specific needs, while it also reduces the time and the cost required for
these inspections. Its applicability and advantages are demonstrated
through two numerical examples.