Sizing parking facilities at airports

Established rules-of-thumb and industry guidelines for estimating the supply of parking at airports are based on uncertain quantities such as design year enplanements and number of airport employees, and are independent of cost. In the presence of continued uncertainty and increasing competition for limited space in and around airports, it is important that facilities are sized in relation to cost of providing and using them. A probabilistic model based on the classical “newsboy” problem is proposed to determine the optimal supply of parking in relation to expected total cost while treating demand as a random quantity. Empirical data are used to demonstrate the application of the proposed model for decision making. In addition to construction and maintenance costs, and user costs, decisions are shown to be sensitive to the level of uncertainty of design year enplanements.     

Autonomy, bureaucracy, professionalism and accountability: a transaction cost approach to shipboard controls

In recent years, shipping industry has encountered severe competition, technological change, and environmental and safety concerns. In order to remain competitive, firms need to review and redesign shipboard work. A crucial aspect of these efforts is shipboard controls that define the extent of autonomy and accountability of officers and crew. This study examines four types of controls on board ships. These are monitoring and autonomy, outcome accountability, formalization and professionalization. The study applied trancsaction cost theory to test eight hypotheses on board 16 ships in two companies. The results largely confirm theoretical predictions. Task visibility, complexity and uncertainty show strong relationships to the four types of controls. However, there are also significant gaps in that accountability for outcomes is low, and situation with regard to crew training and autonomy can be improved. Implications for human resource practice and future research are discussed.     

基于节气门位置传感器的发动机故障诊断研究

通过在VOLVOB230F型电控汽油喷射发动机上研究节气门位置传感器的全负荷信号对发动机性能的影响．并对节气门位置传感器故障造成的发动机性能变化的对比可分析表明：节气门位置传感器的全负荷信号丢失以后，混合气变稀，功率下降；CO和HC排放降低，NOx排放升高，同时有助于指出了节气门位置传感器在电控发动机故障诊断中的作用。     

Comment: Tankers' modification economics: Is there an arbitrage?

In this paper we address the following question: how much is a ship-owner willing to pay in order to convert his single-hull vessel to a double-hull vessel? Our research is motivated by a recent article in Tradewinds, according to which owners have become reluctant in scrapping their vessels by turning them into double hull from single hull. We apply a structural no-arbitrage condition for deriving and estimating 'good-deal' bounds.