Problem statement: It has been posited that insufficient funding for lock maintenance on the inland waterway system causes scheduled and unscheduled delays that greatly threaten inland waterway system performance. We seek to express this in a concrete form and explore quantitatively the extent to which it may be true.

Approach: Our approach is to estimate statistical models using Lock Use, Performance, and Characteristics data published by the US Army Corps of Engineers (USACE) Navigation Data Center. Important to this approach are that the models should seem practically appropriate, and special attention should be paid to the possibility of interaction among lock unavailability and usage variables.

Results: Apparently, the cost of scheduled unavailability for lock maintenance expressed in disrupted commodity flow is in its fixed component; the decision to interrupt commodity flow is what affects inland waterway system performance compared with the extent to which flow is interrupted in time. At the same time, the cost of unscheduled unavailability (e.g. lock closures due to disrepair and natural causes) is in its variable component, meaning the extent to which flow is interrupted in time more greatly affects inland waterway system performance.

问题statemen牛逼：已假定，对内河航道系统锁定维护经费不足导致定期和不定期的延迟，大大威胁到内陆水道系统的性能。我们试图以一种具体的形式表达这一点，并从数量上探讨它可能真实的程度。

方法：我们的方法是使用美国陆军工程兵团（USACE）导航数据中心发布的“锁使用，性能和特征”数据来估计统计模型。对于此方法而言，重要的是模型应该看起来切实可行，并且应特别注意锁不可用和使用变量之间相互作用的可能性。

结果：显然，计划中的锁维护不可用所造成的成本以商品流动中断为准；与及时中断流量相比，中断商品流量的决定是影响内陆水道系统性能的因素。同时，计划外的不可用的成本（例如，由于失修和自然原因而导致的船闸关闭）的代价是可变的，这意味着及时中断水流的程度会极大地影响内陆水道系统的性能。