Packing While Traveling: Mixed Integer Programming for a Class of Nonlinear Knapsack Problems

Packing and vehicle routing problems play an important role in the area of supply chain management. In this paper, we introduce a non-linear knapsack problem that occurs when packing items along a fixed route and taking into account travel time. We investigate constrained and unconstrained versions of the problem and show that both are NP-hard. In order to solve the problems, we provide a pre-processing scheme as well as exact and approximate mixed integer programming (MIP) solutions. Our experimental results show the effectiveness of the MIP solutions and in particular point out that the approximate MIP approach often leads to near optimal results within far less computation time than the exact approach

Emergency preparedness to accidental chemical spills from tankers in Istanbul Strait

Istanbul Strait is one of the most important and dangerous maritime passage in the world. In this study, the hazards for possible accidents of the tankers carrying various chemicals through the Istanbul Strait were investigated and a significant risk was identified due to the intensive transportation of the chemicals. The purpose of this work is to define some risk control options in order to establish an efficient management system which can minimize the probability of accidents and hazardous effects of possible chemical spills to human life and environment. The risk is assessed by using the Formal Safety Assessment Methodology of the International Maritime Organization. Following this methodology hazards of accidents were identified through a questionnaire which is applied to a group of experts focussed on a passage of Istanbul Strait. In addition to this, a frequency analysis of the accidents was carried out on the defined sections along the strait using the accident database in order to determine the geographical distribution of the type and cause of the accidents. On the other hand, the maritime traffic of the Istanbul Strait was simulated using computer based software in order to investigate the effects of the local traffic on the passage. As a conclusion of the simulation the hot spots were defined as the potential locations for collisions. Also the consequences of such probable accidents were evaluated by using different dispersion modelling software for the spilled chemicals. As a result, a comprehensive management system for preparedness and response to chemical spills in the Istanbul Strait were proposed by taking into account the current management system and response equipment. Furthermore, a detailed economic analysis of the proposed system was also performed

Physical Electronics

Contains reports on three research projects

An Exploration of Critical Care Professionals\u27 Strategies to Enhance Daily Implementation of the Assess, Prevent, and Manage Pain; Both Spontaneous Awakening and Breathing Trials; Choice of Analgesia and Sedation; Delirium Assess, Prevent, and Manage; Early Mobility and Exercise; and Family Engagement and Empowerment: A Group Concept Mapping Study

OBJECTIVES: The goals of this exploratory study were to engage professionals from the Society for Critical Care Medicine ICU Liberation Collaborative ICUs to: 1) conceptualize strategies to enhance daily implementation of the Assess, prevent, and manage pain; Both spontaneous awakening and breathing trials; Choice of analgesia and sedation; Delirium assess, prevent, and manage; Early mobility and exercise; and Family engagement and empowerment (ABCDEF) bundle from different perspectives and 2) identify strategies to prioritize for implementation. DESIGN: Mixed-methods group concept mapping over 8 months using an online method. Participants provided strategies in response to a prompt about what was needed for successful daily ABCDEF bundle implementation. Responses were summarized into a set of unique statements and then rated on a 5-point scale on degree of necessity (essential) and degree to which currently used. SETTING: Sixty-eight academic, community, and federal ICUs. PARTICIPANTS: A total of 121 ICU professionals consisting of frontline and leadership professionals. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A final set of 76 strategies (reduced from 188 responses) were suggested: education (16 strategies), collaboration (15 strategies), processes and protocols (13 strategies), feedback (10 strategies), sedation/pain practices (nine strategies), education (eight strategies), and family (five strategies). Nine strategies were rated as very essential but infrequently used: adequate staffing, adequate mobility equipment, attention to (patient\u27s) sleep, open discussion and collaborative problem solving, nonsedation methods to address ventilator dyssynchrony, specific expectations for night and day shifts, education of whole team on interdependent nature of the bundle, and effective sleep protocol. CONCLUSIONS: In this concept mapping study, ICU professionals provided strategies that spanned a number of conceptual implementation clusters. Results can be used by ICU leaders for implementation planning to address context-specific interdisciplinary approaches to improve ABCDEF bundle implementation

Exact Solution Methods for the kk-item Quadratic Knapsack Problem

The purpose of this paper is to solve the 0-1 $k$-item quadratic knapsack problem $(kQKP)$, a problem of maximizing a quadratic function subject to two linear constraints. We propose an exact method based on semidefinite optimization. The semidefinite relaxation used in our approach includes simple rank one constraints, which can be handled efficiently by interior point methods. Furthermore, we strengthen the relaxation by polyhedral constraints and obtain approximate solutions to this semidefinite problem by applying a bundle method. We review other exact solution methods and compare all these approaches by experimenting with instances of various sizes and densities.Comment: 12 page

A systematic review of implementation strategies for assessment, prevention, and management of ICU delirium and their effect on clinical outcomes

Introduction: Despite recommendations from professional societies and patient safety organizations, the majority of ICU patients worldwide are not routinely monitored for delirium, thus preventing timely prevention and management. The purpose of this systematic review is to summarize what types of implementation strategies have been tested to improve ICU clinicians' ability to effectively assess, prevent and treat delirium and to evaluate the effect of these strategies on clinical outcomes. Method: We searched PubMed, Embase, PsychINFO, Cochrane and CINAHL (January 2000 and April 2014) for studies on implementation strategies that included delirium-oriented interventions in adult ICU patients. Studies were suitable for inclusion if implementation strategies' efficacy, in terms of a clinical outcome, or process outcome was described. Results: We included 21 studies, all including process measures, while 9 reported both process measures and clinical outcomes. Some individual strategies suc

Physical Electronics

Contains reports on three research projects

Physical Electronics

Contains reports on three research projects