RESEARCH PROJECTS
The two-product economic lot size scheduling problem with allowed shortages All
of the economic lot scheduling models in the literature have one common
assumption, which states that the production facility has enough capacity
to meet the demand for all products. In this research, we investigate a
restricted version of the ELSP problem when the assumption of machine capacity
is relaxed. This implies that the sum of the demand rates of all products
will be higher than the production rate. As a result, shortages will occur
and a decision has to be made as to how the lost sales should be distributed
among the different products. The ultimate objective is to formulate a
policy to minimize overall costs, which are incurred due to setup, holding
inventory, and shortages. The ELSP problem with forced shortages will be
analyzed for the two-product case using the common cycle approach. N.
E. Abboud. (Supported by URB.)
The finite production rate inventory problem with machine breakdowns: a random walk approach The
production-inventory system with breakdowns behaves as a general random
walk problem with two reflecting boundaries. The first boundary is when
the on-hand inventory is zero. The second boundary in determined by a threshold
level that limits the maximum on-hand inventory. In addition, we assume
that the failure rate of the system is a constant a
per unit time, while the repair rate is b
per unit time. Based on the above assumptions, we model the inventory system
as a discrete-time Markov chain, where the on-hand inventory and the status
of the production facility will both determine the state of the Markov
process. Using potentials from Markov chain theory, we determine the expected
inventory level which will be used to build the cost function. Finally,
we construct an algorithm that determines a cost minimizing threshold level
for a given set of cost parameters. N. E. Abboud. (Supported
by URB.)
Feasibility study for power plants emissions reduction Combustion
processes, and mainly those used for electric power generation, are regarded
worldwide as the major source of air pollution. Consequently, different
techniques and measures are being used to reduce their impact on the environment.
These measures include, and are not restricted to, using fuel with less
sulfur content and installing pollutant control systems to filter the gases
before being emitted to the atmosphere. Flue gas desulfurization systems
are regarded as the most established systems used in modern power plants
to reduce mainly the sulfur doxide emissions. The aim of this project is
to conduct an engineering economy study for implementation of either of
these solutions in the Zouk power plant in Lebanon, with emphasis on the
effects of including the social costs in this study. N. E. Abboud
and F. B. Chaaban. (Supported by URB; LNSCR.)
Investigation of analytical tools for performance modeling of infrastructure systems This
project involved the application of the neural network technique to the
problem of predicting the performance of highway infrastructure surfaces.
Experimental performance data collected over a period of about eight years
were used in the analysis. Comparisons between the predictions given by
the constructed neural networks and those obtained using statistical techniques
were made. Variables found to be significant to neural networks’ learning
included construction parameters, traffic, materials properties, and weather.
M. A. Abdul-Malak. (Supported by URB.)
Management of phased construction projects: owner’s perspective Under
phased construction, packages are started one at a time as the design development
progresses from the conceptual and preliminary phases into the detailed
phase. cost and duration of a phased project evolve from being entirely
estimated, to being less uncertain when tenders are received, and eventually
to being projected estimates incorporating actual changes. The objective
of this research is to investigate methodologies that may be suitable in
addressing the planning and concerns of projects’ owners from the standpoints
of cost and time. M. A. Abdul-Malak. (Supported by URB.)
Problems of human resources in the construction industry Many delays and cost overruns in construction projects are
attributed to problems with human resources. This human factor is very
critical to the success or failure of construction firms. Therefore managing
people and developing their skills are very important to the construction
industry because human resources could be a major barrier. The objective
of this research was to assess human resource problems in construction,
and develop some strategies that will reduce or eliminate these human barriers.
Different managerial levels in construction firms were investigated. In
addition, we looked at issues such as delegation of work, conflict of interests,
skills and knowledge of professionals, human resources development, and
other issues related to the successful execution of construction projects.
T. Mezher. (Supported by URB.)
Multiobjective programming approach to energy resource allocation problems The traditional energy resources allocation problem is concerned
with the allocation of limited resources among the end-uses such that the
overall return is maximized. In the past, several techniques were used
to deal with such a problem. In this paper, the energy allocation process
is looked at from two points of view: economy and environment. The economic
objectives include costs, efficiency, energy conservation, and employment
generation. The environmental objectives consider environmental friendliness
factors. The objective functions are first quantified and then transformed
into mathematical language to obtain a multiobjective allocation model
which will be carried out using preemptive goal programming techniques.
It will be shown that the proposed method allows decision makers to encourage
or discourage specific energy resources for the various household end uses.
The case of Lebanon is studied to illustrate the usefulness of the proposed
technique. T. Mezher. (Supported by URB.)
Abboud, N. E., The Markorian two-echelon repairable item provisioning problem. Journal of the Operational Research Society, 47 (2), 284-296, 1996. ———, Time-limited free backorders QOQ model. Journal of Applied Mathematical Modelling, 21 (1), 21-25, 1997. ———, A simple approximation of the EMQ model with poisson machine failures. Production Planning and Control, 8 (4), 385-397, 1997. Abdul-Malak, M. A., Fowler, D. W.*, and Constantine, C.*, Aggregates characteristics governing the performance of seal coat highway overlays. Transportation Research Record, 8 (1547), 15-22, 1996. Abdul-Malak, M. A., Mezher, T. and Murphree, E. L.*, Division support system framework for construction technology transfer and diffusion. Transportation Research Record, 7 (1491) 49-61, 1995. Mezher, T., Using expert critiquing systems in engineering education and training. Computers in Education, ASEE, 6 (2), 43-49, 1996. Salameh, M. K., Buffer stock under the effect of fluctuating demand. Production Planning and Control, 8 (1) 37-40, 1997. Salameh, M. K. and Jaber, M. Y., Optimal lot sizing under learning considerations: shortages allowed and backordered. Applied Mathematical Modeling Journal, 19, 307-310, 1995. ———, Reserve stock and transshipment in hierarchical inventory systems. Production Planning and Control, 8 (5), 1997. ———, Optimal lot sizing maintenance interruptions. Applied
Mathematical Modeling, 21, 86-90, 1997.
ABSTRACTS, PRESENTATIONS AND PROCEEDINGS Abboud N. E., Production lot sizing with machine breakdowns: a simulation study. First LAAS International Conference on Computer Simulation, Beirut, Lebanon, 263-268, 1995. ———, An approximate model to the production lot-sizing problem with Poisson machine breakdowns and low failure rate. International Conference on Industrial Engineering and Production Management, Marrakech, Morocco, 1, 33-42, 1995. Abdul-Malak, M.A., Management of fast-track construction projects. The ASCE-SAS Second Regional Conference on Save the Environment, 755-762, Beirut, Lebanon, 1995. ———, Integrated infrastruction management: A point of view. International Conference on the Rehabilitation and Development of Civil Infrastructure Systems, 1056-1060, Beirut, Lebanon, 1997. ———, Organizing and planning for community-based rural infrastructure construction. International Conference on the Rehabilitation and Development of Civil Infrastructure Systems, 433-443, Beirut, Lebanon, 1997. Daya, M., Mezher, T., and Abdul-Malak, A. M., Computer-aided management platform for the telecommunication infrastructure construction. International Conference on Rehabilitation and Development of Civil Engineering Infrastructure Systems, Beirut, Lebanon, June 1997. Mezher, T., Sustainable development strategies for Lebanon. ASCE-SAS Second Regional Conference, 411-422, Beirut, Lebanon, 1995. ———, Simulating human critics. First LAAS International
Conference on Computer Simulation, 319-325, Beirut, Lebanon, 1995.
Azar, M., Neural networks’ computational use in pavement management (1997). Advisor: M. Abdul-Malak. Bachour, N. V., Productivity and materials handling improvement at SIPCO Gandour: a paper manufacturer (1996). Advisor: N. Abboud. Chalala El-Khoury, N., The exact time discounting of the finite production model (1996). Advisor: M. Salameh. Chehayeb, W., Project cash-flow analysis: contractor’s viewpoint (1996). Advisor: M. Abdul-Malak. Daher, R. Y., Effect of random machine unavailability time on the finite production inventory model (1995). Advisor: N. Abboud. Damous, A., Quality function deployment in construction (1997). Advisor: T. Mezher. Daya, M., Building a decision support system for the public switching telephone network (PSTN) project (1996). Advisor: T. Mezher. Diab, A., Strategic planning for electric power generation (1997). Advisor: M. Abdul-Malak. El-Akawi, W., The effect of on-line help files on students’ learning abilities (1997). Advisor: T. Mezher. Hanna, E.E., Booking policies for flights with two legs (1995). Advisor: N. Abboud. Jarroush, C., Fuzzy linear programming application on energy resources allocation (1997). Advisor: T. Mezher. Khalil, R., Effect of random failure on the finite production model (1995). Advisor: M. Salameh. Maarouf, B., An improved user interface for a technology transfer critiquing system (1997). Advisor: T. Mezher. Moukahal M.-R., Decision support system for construction technology transfer and diffusion (1995). Advisor: M. Abdul-Malak. Nabbout, A., Assessment of human resources in the Lebannese construction industry (1997). Advisor: T. Mezher. Nasrallah, M., Assessment of the utilization of the construction management principles: a potential for increasing performance and cost benefits (1996). Advisor: T. Mezher. Nizam, Y., Central banking and information technology in Lebanon (1996). Advisor: T. Mezher. Osseiran, R., Investigation of unbalancing in construction bid prices (1997). Advisor: M. Abdul-Malak. Saab, W., Production maintenance (1997). Advisor: T. Mezher. Seferian, G., Development of material and construction specifications for seal-coat highay overlays (1996). Advisor: M. Abdul-Malak. Sfairy, R. G., Time-limited free backorders EOQ model (1995). Advisor: N. Abboud. Shaib, A., A queuing application on the radiology service at Hotel Dieu de France (1995). Advisor: M. Salameh. Tabanji, W. E., Environmental imapcts of power generation: assessment and solutions (1996). Advisor: N. Abboud. Tawil, W., Causes of delays in large building construction projects in Lebanon (1997). Advisor: T. Mezher. Theodory, S., The land and socio-economic evaluation of the Elissar area (1995). Advisor: M. Salameh. Zahabi, W., A multiobjective programming approach to energy resource allocation proin Lebanon (1996). Advisor: T. Mezher.
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