Determination of statistical homogeneity by comprehensively considering the discontinuity information

Statistička homogenost stijenske mase oduvijek je važno pitanje u inženjerstvu stijenske mase. U ovom je radu analizirana stijenska masa podzemnog skladišta nafte na otoku Huang usmjerena na raspodjelu statistički homogenog područja. Duljina rasprostiranja je osnovni element za određivanje karakteristika pukotina. Stijenska masa različitih duljina rasprostiranja pukotina uvelike se razlikuje kad se radi o mehaničkim i karakteristikama deformacije. Ovaj rad obuhvaća podatke o duljini rasprostiranja u podjeli statistički homogenog područja i razmatra vrijednosti varijance i srednje vrijednosti uzoraka pukotina odvojeno u različitim područjima F-testom i T-testom kako bi se utvrdilo imaju li uzorci statistički slične podatke o duljini rasprostiranja. Potrebni su brojni uzorci pukotina da bi se dobilo statistički homogeno područje. U ovom je radu primijenjen Watsonov test za određivanje statistički homogenog područja i razmatrani su podaci o pojavi pukotina u svrhu dobivanja manjeg broja uzoraka za usporedbu pojave pukotina. Podaci o postojanju pukotina i duljini rasprostiranja analiziraju se uvođenjem F-testa, T-testa i Watson-testa kako bi se dobili osnovni podaci o pukotinama i objektivni i prihvatljivi rezultati za statističku homogenost.The statistical homogeneity of rock mass has always been an important issue in rock mass engineering. The rock mass of national underground oil storage in Huang Island is analyzed in this study with focus on the division of a statistically homogeneous area. Trace length is a basic element in determining crack features. The rock mass of different track lengths differs widely in terms of mechanics and deformation characteristics. This study includes trace length information in the division of a statistically homogeneous area and considers the variances and mean values of crack samples in different regions separately by F-test and T-test to determine if the samples have statistically similar trace length information. Numerous crack samples are required to divide a statistically homogeneous area. This study adopts the Watson test to divide a statistically homogeneous area and considers data on crack occurrence to achieve the purpose of obtaining fewer samples for occurrence comparison. Crack occurrence and trace length information are considered by integrating F-test, T-test, and Watson test to gather adequate basic information on cracks and obtain objective and reasonable results for statistical homogeneity

Estimating project overheads rate in bidding: DSS approach using neural networks

[[abstract]]Project overheads estimation by applying a selected rate as a percentage of direct cost is used widely in bidding in construction, but the rate is prone to inaccuracy if it is selected subjectively. An improved approach is developed, a decision support system (DSS) based on a construction firm’s cost data and using a neural network model for mapping of overheads rates from project attributes. The estimating ability of the proposed DSS is continually updated by retraining the neural networks with accumulated cost data in an expanding project database. An illustrative example is provided, in which the creation and updating of a prototype neural network model were simulated using cost data for projects spanning six years. The model explains the effects of duration and direct cost on overheads rates that the regression method fails to account for. The results also give empirical evidence that the DSS is capable of improving accuracy through annual model updating and may be used as a means for implementing organizational learning. The methods for assessing the loss risk for a bid incorporating an estimate from the DSS are provided

Heating Control of Heated Twin Radiosonde Humidity Sensor Based on DMC

In order to effectively solve condensation and icing problems of radiosonde in low-temperature environment at high altitude, humidity sensor heated automatic alternately to remove pollution and improve the measurement accuracy. Heat experiments obtained the curve of rising temperature and responsible time on heated twin humidity sensor in normal temperature and pressure, by expanded responsible curve to obtain heated model of twin heated humidity sensor and by the analysis of heating model, use DMC and PID control for heating respectively. Simulation results show that the DMC control meets the practical requirements of measure at high altitude