ESTEGHLAL
Year:2005 | Volume:24 | Issue:1|Papers Count:9

Generation Expansion Planning (GEP) is one of major modules of power system planning studies, normally performed for the nex 10-30 years horizon. The current industrial practices are to find the generation requirements based on a nodal an analysis. .In this way, the allocations are not determined and subsequent studies are required to find the exact locations which as decomposed from the earlier stage, may result in non-optimum solution. A new approach is proposed in this paper in which, based on dynamic programming and sensitivity factors, GEP is performed with due to consideration of transmission system effects. In this way, the allocations of justified generation plants are also determined. The results for Iranian Power Grid for the years 201I to 2021 are demonstrate.

With progress in radar systems, a number of methods have been developed for signal processing and detection in radars. A number of modern radar signal processing methods use time-frequency transforms, especially the wavelet transform (WT) which is a well-known linear transform. The interference canceling is one of the most important applications of the wavelet transform. In Ad-hoc detection methods, the interference is firstly canceled and then a simple detector, like an energy detector, is used. Therefore, we have used wavelet-based approaches to cancel the interference and then an energy detector has been employed. In this paper, it is shown that in practical cases where the performance of matched filter or near-matched filter is degraded, wavelet-based methods are more efficient. Also, we have shown that for cases where targets with slow radial velocity or one dose to blind velocity are removed by the MTI filter, wavelet based denoising has a better performance.

Time-cost trade-off is one of the most important subjects in project management and of interest to contractors. The goal of time-cost trade-off is sensivity analysis of project costs to changes in activity duration in order to obtain the best combination of activity duration decrease, in fl way that the sum of project costs is minimized. In the heuristics presented in this area, time crashing is on the base of the minimum cost slope of activities. But since projects are usually performed over long periods, they can be affected by interest rate. In this paper, a new heuristic algorithm is presented in order to obtain the best combination of activity duration decrease while the monetary value is taken into account, with the goal of minimizing the sum of present value of project costs.

A special class of the knapsack problem is called the separable nonlinear knapsack problem. This problem has received considerable attention recently because of its numerous applications. Dynamic programming is one of the basic approaches for solving this problem. Unfortunately, the size of state-pace will dramatically increase and cause the dimensionality problem. In this paper, an efficient algorithm is developed to find surrogate multipliers in each stage of dynamic programming in order to transform the original problem to a single constraint problem called surrogate problem. The upper and lower bounds obtained by solving the surrogate problem can eliminate a large number of state variables in dynamic programming and extremely reduce the duality gap according to our computational results.

Rainfall is one of the most important climatic variables in the hydrology cycle. In flood estimation as well as environmental pollution studies in medium to large watersheds not on only must temporal pattern of rainfall be known, but also the knowledge of its spatial distribution is required. Estimation of daily rainfall distribution without comparison and selection of suitable methods may lead to errors in input parameters of rainfall - runoff models. Interpolation methods are among the techniques for estimating spatial distribution of rainfall. In this study, Thin Plate Smoothing Spines (TPSS), Weighted Moving Average (WMA) and Kriging are applied to estimate spatial distribution in the southwest of Iran. Cross validation technique is used for comparison and evaluation of the methods. The results of analysis with two different station density showed that the TPSS method with power of 2 is the most accurate method in estimating daily rainfall. Zoning of the region also increased the interpolation accuracy. Generally speaking, division of the region based on cluster analysis improves accuracy compared with division by inter basin boundaries.

In recent years, determining bearing capacity of piles from in-situ testing data as a complement to static and dynamic analysis has been used by geotechnical engineers. In this paper, different approaches for estimating bearing capacity of piles from .SPT data are studied and compared. A new method based on N value from SPT is presented. Data averaging, failure zone and plunging failure of failure revisited in the light of this new method. A data bank was compiled including 42 full scale pile load tests in sites where SPT was performed close to pile locations. Comparison of current methods by error investigation with statistical and cumulative probability approaches demonstrates that the new method predicts pile capacity with more accuracy and less scatter than others. Therefore, it can be applied as a suitable solution in geotechnical design.

Forced hydraulic jump in a horizontal stilling basin with one and two continuous sills at the downstream end of an ogee standard weir was investigated. Experiments were completed on sills of jive different heights which were fixed at two different distances from the toe of the weir. The main characteristics of the jump such as the sequent depth ratio, relative roller length, and relative energy loss were analysed. Based on the momentum equation and using an experimental coefficient, a method was adopted to predict the sequent depth ratio. Using the results of the experiments, an analytical expression was developed for the prediction of the relative roller length. These methods agree well with the writers and other investigators experiments. The results of experiments on one and two prolonged sills showed that by increasing the height of the sill or shortening the distance of the sill from the toe of the weir, the reduction of the sequent depth and also the roller length obtains, but the energy loss increases.

Five methods are introduced for design of castellated I beams encased in concrete. One of the methods, plastic analysis, is thoroughly I explained and the relevant equations are developed. Eight castellated beams encased in concrete are made and tested. The theoretical design methods are all compared with the test results and the safety factor for each method is calculated. The results show that the plastic method of analysis and design is the most economical, which also gives a reasonable safety factor against beam failure.

Contaminant transport analysis was performed for four selected solid waste landfill designs using the computer code POLLUTE. The diffusion coefficients were determined for the natural soils (aquitard) and compacted soils from the Urumia landfill site, using the diffusion tests. These coefficients along with the geometrical, physical, and chemical parameters of the natural soil and engineered layers, as well as the dominant boundary conditions were used in the analysis of the four selected resigns for the landfill. These designs were evaluated for the contamination of the underlying aquifer in a specified period, using he drinking water standard for chloride ion. The comparisons showed that the fourth design which includes the engineered laments of a blanket type leach ate collection layer and a compacted clayey liner underneath the landfill base, has more certainty n controlling the contaminant transport from the landfill base to the underlying aquifer. This type of landfill could be introduced IS an optimum and semi-engineered design to be used for solid waste landfills in Iran.