Consider the problem of learning how long to wait for a bus before walking, experimenting each day and assuming that the bus arrival times are independent and identically distributed random variables with an unknown distribution. Similar uncertain optimal stopping problems arise when devising power-saving strategies, e.g., learning the optimal disk spin-down time for mobile computers, or speedi...

We study the rate of true vacuum bubble nucleation numerically for a φ4 field system coupled to a source of thermal noise. We compare in detail the cases of additive and multiplicative noise. We pay special attention to the choice of initial field configuration, showing the advantages of a version of the quenching technique. We advocate a new method of extracting the nucleation time scale that ...

Motivated by service levels in terms of the waiting-time distribution seen, for instance, in call centers, we consider two models for systems with a service discipline that depends on the waiting time. The first model deals with a single server that continuously adapts its service rate based on the waiting time of the first customer in line. In the second model, one queue is served by a primary...

Introduction Perceived waiting time (PWT) at signalized intersections differs from the real value of waiting time (WT), and varies with signal design. The onerousness of delay depends on the conditions under which it is experienced. Using weighted travel time may contribute to optimal signal control if its use can improve upon assuming that all time is weighted equally by users. This research e...

In this paper we study a single-server queue with FIFO service and cyclic interarrival and service times. An efficient approximative algorithm is developed for the first two moments of the waiting time. Numerical results are included to demonstrate that the algorithm yields accurate results. For the special case of exponential interarrival times we present a simple exact analysis.

Patient hospital choice reform in Norway was introduced in 2001. Waiting times for treatments at hospitals were published, and patients and their physicians were able to select hospitals for services. We develop a model of patient response, and study the empirical impact of the reform. Our data set consists of hospital admission information between 1999 and 2005, as well as hospital and area ch...

Sleep quality has a large impact on daily performance and general health. Among the different methods of objectively measuring sleep quality, actigraphy continues to be very popular. It can take continuous activity measurements over several days in order to determine sleep-wake cycles and calculate sleep variables, including the three standard sleep variables used in determining sleep quality: ...

The distribution of times ∆t between coronal mass ejections (CMEs) in the Large Angle and Spectrometric Coronagraph (LASCO) CME catalog for the years 1996-2001 is examined. The distribution exhibits a power-law tail ∝ (∆t) with an index γ ≈ −2.36± 0.11 for large waiting times (∆t > 10 hours). The powerlaw index of the waiting-time distribution varies with the solar cycle: for the years 1996-199...

Hospitals aim to deliver the highest quality of care. One key priority is to schedule emergency surgeries as quickly as possible, because postponing them generally increases a patient’s risk of complications and even death. In this paper, we consider the case that emergency surgeries are scheduled in one of the elective Operating Rooms (ORs). In this situation, emergency patients are operated o...

BACKGROUND Waiting time is an important indicator of patient satisfaction and the quality of care. The aim of this study is to determine the waiting time in physician offices in Tehran, Iran.   METHODS This was a cross-sectional study. The target population of this study consisted of specialist and subspecialist offices in Tehran. We used a census sampling method to study the population. Data...