Hassling as Money Burning: A Note

Why do states sometimes permit military activities that are minor, costly, and yet inconclusive? We argue that these low-level conflicts known as "hassling" are useful commitment tactics to prevent preventive wars. While states have incentives to cooperatively and permanently refrain from hassling, they recognize that doing so might beget a preventive war due to the rising power's inability to make appeasing offers prior to the power shift. Maintaining the hassling activities that might persist after a greater war would reduce the spoils of the victor, thus dampening the declining power's preventive war incentive. As such, costly hassling activities are efficient in the sense that they preclude costlier large-scale wars

Accountability and Motivation

Successful reform policy-making commonly involves correct policy choices followed by high-quality implementation. When political decision makers have to do both, office-holding motives often prevent them from acting in a way that best serves the public interest. I build a formal model to examine how a decision maker with conflicting policy and office-holding motives makes reform policies in several salient information environments. My model highlights the difficulty of fine-tuning the decision maker's motives in a context where pandering is inevitable. I show that backing away from full transparency often helps -- not by eliminating pandering, but by lending credibility to a retention rule that varies with reform outcomes -- to provide a high-powered incentive for implementation. Excessively stringent or lenient transparency requirements direct the decision maker's attention to acting congruently without taking the policy consequences seriously

Brain tumor segmentation with minimal user assistance

In this thesis, we propose a brain tumor segmentation system that requires only 4 clicks from users to specify a tight bounding box that completely contains the tumor. We convert the segmentation problem to an energy minimization problem. We utilize the basic energy function that combines intensity appearance and boundary smoothness. Global and local appearance models are experimented and compared in our work. The basic energy function does not assume any shape prior and thus leads to unrealistic shapes. We take the advantage of the fact that most of the tumors are approximately convex in shape and incorporate the star shape prior to prohibit unlikely segmentations. Another problem with the basic energy function is the undersegmentation problem. With the bounding box provided by the user, we are able to have a rough idea of the tumor size. Therefore, to encourage the segmentation to be a certain size, we add volumetric bias to our energy, which helps solve this problem. We also try to model the tumor as multi-region object where regions have distinct appearance. Specifically, we incorporate interior+exterior model for the tumor into our energy function. Our final result is promising in terms of f-measure. Our best performance for 88 volumes is 87% using volumetric ballooning

A rational choice theory of midlife crises

This paper models the midlife crisis as a decision on whether and when to realize a life dream, incorporating the key components of three psychology theories of midlife crises. It explains why a crisis (dream realization) tends to occur in the midlife if it occurs at all. Other results include that one either realizes his dream fully or not at all, that a shorter life expectancy makes a midlife crisis more likely, and that “crazier†dreams tend to be postponed to a later time in life.midlife crisis, dream, aging, death