The Certainty of Uncertainty: Understanding and Exploiting Probability-Based Aviation Weather Products

Probability-based weather forecasts (i.e., forecasts that quantify uncertainty) have been available for certain weather elements for over 40 years; for example, the probability of precipitation forecast. More recently, probability forecasts designed specifically for aviation have become widely available on the internet through two National Weather Service (NWS) forecast centers, the Aviation Weather Center (AWC) and the Environmental Modeling Center (EMC). Although these probability-based products are generally not recognized by the Federal Aviation Administration (FAA) for operational use, their potential is beginning to be recognized by the aviation community. For example, the Joint Program Development Office (JPDO) Next Generation Air Transportation System (NEXTGEN) Air Traffic Management (ATM)-Weather Integration Plan cites probabilistic forecasts as playing a key role in future air traffic management decision support tools by the year 2023 (JPDO, 2010). Specifically, the JPDO identified the integration of weather uncertainty information (i.e., probabilities and confidence information) into decision-support tools as the highest of four levels of weather integration into the air traffic management system

The promotion of local wellbeing: A primer for policymakers

There is growing interest among policymakers in the promotion of wellbeing as an objective of public policy. In particular, local authorities have been given powers to undertake action to promote wellbeing in their area. Recent advances in the academic literature on wellbeing are giving rise to an increasingly detailed picture of the factors that determine people’s subjective wellbeing (how they think and feel about their lives). However, the concept of subjective wellbeing is poorly understood within local government and much of the evidence base is extremely recent. I therefore review the literature on the definition, measurement, and determinants of wellbeing, and discuss some of its implications for local public policy

Human dynamics in the age of big data: a theory-data-driven approach

The revolution of information and communication technology (ICT) in the past two decades have transformed the world and people’s lives with the ways that knowledge is produced. With the advancements in location-aware technologies, a large volume of data so-called “big data” is now available through various sources to explore the world. This dissertation examines the potential use of such data in understanding human dynamics by focusing on both theory- and data-driven approaches. Specifically, human dynamics represented by communication and activities is linked to geographic concepts of space and place through social media data to set a research platform for effective use of social media as an information system. Three case studies covering these conceptual linkages are presented to (1) identify communication patterns on social media; (2) identify spatial patterns of activities in urban areas and detect events; and (3) explore urban mobility patterns. The first case study examines the use of and communication dynamics on Twitter during Hurricane Sandy utilizing survey and data analytics techniques. Twitter was identified as a valuable source of disaster-related information. Additionally, the results shed lights on the most significant information that can be derived from Twitter during disasters and the need for establishing bi-directional communications during such events to achieve an effective communication. The second case study examines the potential of Twitter in identifying activities and events and exploring movements during Hurricane Sandy utilizing both time-geographic information and qualitative social media text data. The study provides insights for enhancing situational awareness during natural disasters. The third case study examines the potential of Twitter in modeling commuting trip distribution in New York City. By integrating both traditional and social media data and utilizing machine learning techniques, the study identified Twitter as a valuable source for transportation modeling. Despite the limitations of social media such as the accuracy issue, there is tremendous opportunity for geographers to enrich their understanding of human dynamics in the world. However, we will need new research frameworks, which integrate geographic concepts with information systems theories to theorize the process. Furthermore, integrating various data sources is the key to future research and will need new computational approaches. Addressing these computational challenges, therefore, will be a crucial step to extend the frontier of big data knowledge from a geographic perspective. KEYWORDS: Big data, social media, Twitter, human dynamics, VGI, natural disasters, Hurricane Sandy, transportation modeling, machine learning, situational awareness, NYC, GI

Recreational angler satisfaction: What drives it?

Satisfaction is the reward that recreational anglers receive from their experiences, and it constitutes a relevant management target. Angler satisfaction also shapes preferences for regulations, compliance with rules and general angler behaviours. Because of its central role in recreational fisheries management, it is important to understand what drives angler satisfaction. Our objective was to study the catch and non-catch-related determinants of recreational angler satisfaction using a standardized literature search and synthesizing the literature using meta-analytical techniques. After identifying and screening 279 papers, we obtained K = 172 effect sizes extracted from N = 23 studies that met our inclusion criteria. A three-level random-effects model on Pearson's R, derived from studies relating component satisfaction to overall satisfaction assuming a sum-of-satisfaction model, was fitted. The aggregated effect sizes revealed that catch-related (i.e. catch rate, size of caught fish, fish harvest) and two non-catch-related components (i.e. access to fishing sites and crowding) were most related to angler satisfaction. Other non-catch components (e.g. environmental quality, facilities, perception of relaxation quality) also contributed to angler satisfaction but were of less importance, more variable across studies and in some cases not significant (e.g. perceived water quality, quality of social experience). We conclude changes to access to fishing sites, crowding and a reduction in catch qualities, will in many cases produce dissatisfied anglers. In the absence of local studies, focusing management attention on these components can be recommended if the aim is to satisfy anglers or avoid managerial or social issues that emerge from dissatisfied anglers.European Marine and Fisheries Fund (EMFF)Ministry for Agriculture and Environment Mecklenburg‐Western PomeraniaBundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347Peer Reviewe

A Fairness Investigation on Active Queue Management Schemes in Wireless Local Area Network

Active Queue Management (AQM) is scheme to handle network congestion before it happened by deciding which packet has to be dropped, when to drop it, and through which port have to drop when it has become or is becoming congested. Furthermore, AQM schemes such as Random Early Detection (RED), Random Early Marking (REM), Adaptive Virtual Queue (AVQ), and Controlled Delay (CoDel) have been proposed to maintain fairness when unresponsive constant bit rate UDP flows share a bottleneck link with responsive TCP traffic. However, the performance of these fair AQM schemes need more investigation especially evaluation in WLANs environment. This paper provides an experimental evaluation of different AQM schemes in WLAN environment with presence of two different types of flows (TCP flows and UDP flows) to study the behavior of these AQM schemes which might punish some flows unfairly. The simulation method has conducted in this paper by using Network Simulation 2 (ns-2) with the topology of bottleneck scenario. The result has shown that REM and AVQ both obtain higher fairness value than RED and Codel. However, CoDel has given the lowest fairness comparing with RED scheme which have given a moderated value in terms of fairness in WLANs environment. Besides, AQM schemes must be chosen not only based on its performance or capability to indicate the congestion and recovering overflow situation but also considering fairness with different types of flows and the environment as well, such as WLANs environment