AN ALGORITHM TO IDENTIFY ALL PATHS IN SCHEDULING NETWORKS

The purpose of this paper is to present an algorithm that identifies every path in scheduling networks. The algorithm finds the answer by simulating the way we solve the problem by hand. The result is a list, in sequential order, of all activities involved in each path, the algorithm is divided into forward and backward passes that are repeated until all paths have been identified. Backward passes determine the existence of paths, while forward passes determine the activities involved in the paths. The algorithm has been successfully tested with 31 construction networks, and has been implemented in simulation programs used for construction scheduling and probabilistic analyses.     

HOMOGENEOUS GAS-SOLID SUSPENSIONS FOR EFFICIENT DOWNFLOW REACTORS

In order to increase heat and mass transfer and to accelerate high temperature gas-solids reactions of fine powders, downflow tube-reactors have attracted growing attention. Short reaction times of fractions of a second require short term constant feeding of gas and solids followed by the continuous and rapid formation of homogeneous suspensions with low fluctuations in time to meet required mole ratios. The objective of the present study is the preparation of short-term constant, homogeneous gas-solid suspensions under gravitational flow conditions in downflow reactors. The dynamics of dispersing a very compact dense solids jet lo achieve a homogeneous gas-solid suspension was investigated in a semi-industrial test unit with a maximum solids throughput of 5 t/h and different tube geometries.     

THE DEVELOPMENT OF A KNOWLEDGE-BASED EXPERT SYSTEM FOR UTILIZATION OF COAL COMBUSTION BY-PRODUCT IN HIGHWAY EMBANKMENT

The study in this paper introduces the development of a knowledge-based expert system that helps to determine the suitability of FGD by-product in embankment construction. The expert system shell Personal Consultant Plus was used for this purpose. The knowledge base in the Embankment Construction Expert System (ECES) consists of a root frame and four subframes, and accommodates the production rules obtained from laboratory tests as well as an extensive literature review. An external program to calculate the embankment settlement was integrated into the system. A case study is presented to demonstrate the use of ECES. This study provides the embankment designer with a useful tool for making decisions on FGD by-product application as an embankment material.     

MODIFIED MONTE CARLO SIMULATION FOR PROBABILISTIC SCHEDULING

This paper presents the Simplified Monte Carlo Simulation (SMCS) method. The SMCS method can be used to perform risk analysis of construction networks, and produce results as accurate as Monte Carlo Simulation (MCS) while requiring less computing time. Thirty-one construction networks were used to compare the SMCS results with MCS results. Two cases are presented in this paper. SMCS performs the same type of replications as MCS but in a smaller network, reducing computing time from fifteen to seventy percent when compared with MCS. Moreover, SMCS can be used to identify activities that are more likely to cause delay of the project, as well as activities that are not likely to have impact in the duration of the project.     

IDEOLOGICAL DEVELOPERS AND THE FORMATION OF LOCAL DEVELOPMENT POLICY: THE CASE OF INNER‐CITY PRESERVATION IN TEL AVIV

ABSTRACT: This article studies the role of ideological developers (IDs) in the formation and implementation of local development policy. The IDs are developers whose motivation is ideological as opposed to financial, and they initiate ideas rather than plans and projects. Based on a case study regarding inner‐city preservation, we claim that in Tel Aviv, IDs have much leverage on local decision making. The IDs are individuals with high personal capital, who focus on an issue that it is not championed by existing civil groups. As the IDs seek out influential routes to policy makers, they build circumstantial coalitions. Through these limited and conditional partnerships with administrators and other influential actors, the IDs apply pressure and advance their specific cause.