Optimal scheduling of block lifting in consideration of the minimization of traveling distance while unloaded and wire and shackle replacement of a gantry crane

Nowadays, shipyards are making every effort to efficiently manage their resources such as gantry cranes, transporters, and block stock yards. The scheduling of block lifting for a gantry crane has been manually performed by an expert shipyard manager for many years. Such a practice, however, can lead to an undesirably long time to produce scheduling plans. In addition, the quality of the scheduling plans may not be optimal. To improve the overall process, a block lifting scheduling system for a gantry crane was developed in this study by using optimization techniques. A block lifting scheduling problem was first formulated as a multiobjective optimization problem. For a gantry crane, minimization of the traveling distance while unloaded and wire and shackle replacement between block lifting was considered. An optimization algorithm based on the genetic algorithm was then proposed and implemented so as to solve the problem. To evaluate the efficiency and applicability of the developed system, the system was applied to an actual block lifting scheduling problem in a shipyard. Compared to results achieved by manual scheduling by an expert manager, the results of this work show that blocks can be more efficiently lifted by a gantry crane when the developed system is applied.     

Cruise traveler satisfaction at a port of call

ABSTRACT

No studies have been conducted on cruise traveler expectations for a port of call in Asia. Current literature on general tourism shows that the research to measure traveler satisfaction is divided into two dominant approaches, the disconfirmation model, based on the Expectancy Disconfirmation Paradigm, and the perceptions-only model. However, previous disconfirmation models used different sample populations to measure traveler expectations and perceptions, resulting in biased results. The main objectives of this research was two-fold: (1) to develop a measurement scale for evaluating the expectations of cruise travelers during their visit to a port of call; and, (2) to examine the satisfaction of cruise travelers using the same sample population of the pre-visit expectations and post-visit experiences. The measurement scale for cruise travelers was developed using exploratory factor analysis and confirmatory factor analysis. Three factors, “Overall convenience/People,” “Culture/Exploration,” and “Commodities/Attractions,” were extracted from the analysis. Among these factors, the “Culture/Exploration” factor explained the largest part of overall satisfaction. The results also showed that the perception-only model outperformed the disconfirmation model in explaining overall satisfaction. Additionally, overall satisfaction was found to have a greater impact on the intention to recommend the visit to others than on the intention to revisit.