Mathematical programming models for scheduling locks in sequence

We investigate the scheduling of series of consecutive locks. This setting occurs naturally along canals and waterways. We describe a problem that generalizes different models that have been studied in literature. Our contribution is to (i) provide two distinct mathematical programming formulations, and compare them empirically, (ii) show how these models allow for minimizing emission by having the speed of a ship as a decision variable, (iii) to compare, on realistic instances, the optimum solution found by solving the models with the outcome of a decentralized heuristic

Understanding Post-secondary Student Mobility and its Impact on Wellbeing

There are approximately 30,000 Brock University and Niagara College students making their way around Niagara region to attend school, engage in social activities, and contribute to the local economy through their employment and shopping, among many other activities. Unfortunately, however, transportation barriers discourage or prevent many of these students from fully participating in community life. While numerous studies have examined the linkages between transportation and public health, few have been focused specifically on the post-secondary student demographic, including Niagara’s university and college students. Through the application of a mobilities lens, along with The Five Ways to Wellbeing and Determinants of Health frameworks, this study examines the ways in which students’ levels of transportation accessibility impact their levels of mobility and subjective wellbeing. By applying a mixed methods approach, including an online survey and a photovoice project, this study has found that there are geographic-type and person-type barriers that create inequities and, in some cases, exclusions. Geographically, students living in certain Niagara municipalities, or attending certain campuses, have longer and more convoluted trips leading to a lower sense of satisfaction and subjective sense of wellbeing. Person-type barriers are characteristics that are unique to populations of people such as being domestic or international students, gender and having hidden disabilities. Building on Cresswell’s relational moments of mobility and Flamm & Kaufman’s motility, this study exposes the ‘hidden’ power relations that are fundamental to being mobile subjects and, ultimately, students’ subjective wellbeing

Including farmer irrigation behavior in a sociohydrological modeling framework with application in north India

Understanding water user behavior and its potential outcomes is important for the development of suitable water resource management options. Computational models are commonly used to assist water resource management decision making; however, while natural processes are increasingly well modeled, the inclusion of human behavior has lagged behind. Improved representation of irrigation water user behavior within models can provide more accurate and relevant information for irrigation management in the agricultural sector. This paper outlines a model that conceptualizes and proceduralizes observed farmer irrigation practices, highlighting impacts and interactions between the environment and behavior. It is developed using a bottom‐up approach, informed through field experience and farmer interaction in the state of Uttar Pradesh, northern India. Observed processes and dynamics were translated into parsimonious algorithms, which represent field conditions and provide a tool for policy analysis and water management. The modeling framework is applied to four districts in Uttar Pradesh and used to evaluate the potential impact of changes in climate and irrigation behavior on water resources and farmer livelihood. Results suggest changes in water user behavior could have a greater impact on water resources, crop yields, and farmer income than changes in future climate. In addition, increased abstraction may be sustainable but its viability varies across the study region. By simulating the feedbacks and interactions between the behavior of water users, irrigation officials and agricultural practices, this work highlights the importance of directly including water user behavior in policy making and operational tools to achieve water and livelihood security

Navigating Airwaves and Waterways: An Ethnography of Mobile ICT Use on the Digital Ship

Commercial shipping is a vital part of Canadas economy, moving goods through an intricate network of waterways, lakes, rivers and ports. It is also an industry that is undergoing a remarkable transformation, as new (at least to the industry) digital technologies are taking hold in the wheelhouses and engine rooms of these freighters and tankers. Coupled with the emergence of the digital ship, sailors now have access to a broad array of mobile information and communication technologies, including cellphones, and satellite-based internet access. In light of this, this thesis considers the experiences of sailors who grapple with these changes, to explore how mobile ICTs challenge, complicate, enhance, and otherwise transform their lives. This thesis draws on ethnographic research conducted over a month-long, 4,000 nautical mile journey on an articulated tug and barge that transports liquid asphalt and other black oil products through the Great Lakes-St. Lawrence Seaway system. Drawing upon media studies, science and technology studies, and mobilities studies, I seek to understand the physical, representational, and virtual worlds of sailors as an assemblage of devices, people, movements, geographies and histories. To do so, three interconnected narratives emerge. The first is a story of connectivity, as sailors manage the home-work divide. The second story is about the sociotechnical power of mobile ICTs, as expertise and autonomy are being eroded by the use of digital devices. The third story is perhaps in response to mobile ICTs, a story about how, even with all of these digital and automation technologies now permeating the fabric of sailors everyday lives, they still, first and foremost, rely on their embodied knowledge to do their jobs. I argue that while the virtual and the representational worlds of the sailor are important, the physical world still holds sway

The Influence of Physiological and Abiotic Factors on the Sensitivity of the Sea Lamprey (Petromyzon marinus) to the Lampricide 3-trifluoromethyl-4-nitrophenol (TFM)

Invasive sea lamprey (Petromyzon marinus) in the Great Lakes are controlled using the pesticide (lampricide) 3-trifluoromethyl-4-nitrophenol (TFM), which is applied to nursery streams containing larval lamprey. The toxicity of TFM to lamprey is affected by various environmental and physiological factors, which can lead to residual lamprey that survive TFM treatment. The goal of this study was to investigate how abiotic (season and temperature) factors interacted with physiological parameters (whole body and tissue energy reserves) to influence TFM sensitivity in sea lamprey. Toxicity tests were conducted at different times of the year (spring, early and late summer, fall) and temperatures (6, 12 and 21 °C) using larval sea lamprey collected from the same stream, the Au Sable River, Michigan, USA. Toxicity tests revealed that TFM tolerance was greatest in late summer, when the 12 h LC50 and 12 h LC99.9 were 2.0 to 2.5-fold greater than in the spring and fall, when water temperatures were cooler. Toxicity tests conducted the following year on larval sea lamprey collected from the same river, but acclimated and exposed to TFM at different temperatures, revealed that 12 h LC50 and 12 h LC99.9 increased by 50 % as water temperature increased from 6 °C to 12 °C, and was 2.5-fold greater at 21 °C than at 6 °C. In addition, body composition experiments were conducted on lamprey that were not exposed to TFM to quantify changes in energy stores with season and temperature. Seasonal variation in whole body and tissue energy stores including glycogen, lipid and protein had little influence on the differences in TFM sensitivity. No differences in TFM burden or the TFM metabolite, TFM-glucuronide, were detected in the carcasses of lamprey exposed to TFM during different seasons. Nor could any differences in body condition (condition factor, hepatosomatic index) explain the differences in TFM sensitivity with season. I conclude that increased water temperature is the primary abiotic factor contributing to the larval sea lamprey’s greater ability to withstand TFM during the summer, possibly due to an increase in their capacity to detoxify TFM. These data suggest that it may be prudent to consider seasonal variations in temperature when using current models to select and treat sea lamprey-infested streams with TFM

Joseph H. Engel Interview (MORS)

Interviewers: Dunn, William H.; Sheldon, Robert S. Interview location(s): Fairfax, Virgini

Machine Learning Methods with Noisy, Incomplete or Small Datasets

In many machine learning applications, available datasets are sometimes incomplete, noisy or affected by artifacts. In supervised scenarios, it could happen that label information has low quality, which might include unbalanced training sets, noisy labels and other problems. Moreover, in practice, it is very common that available data samples are not enough to derive useful supervised or unsupervised classifiers. All these issues are commonly referred to as the low-quality data problem. This book collects novel contributions on machine learning methods for low-quality datasets, to contribute to the dissemination of new ideas to solve this challenging problem, and to provide clear examples of application in real scenarios

The efficacy of back calculation methods for determining length at age data and the use of such data to determine growth standards, national growth patterns and recruitment dynamics of roach (Rutilus rutilus (L.)), dace (Leuciscus leuciscus (L.)) and chub (Leuciscus cephalus (L.)) in UK rivers

The use of fish scales to age and back-calculate previous lengths at age and gain age and growth information has long been used as a management tool in fisheries. Calcified structures from fish, including otoliths, fin rays, and vertebrae have been used to gain length at age data. Scales however, are the most common structure used for aging freshwater fish (Borkholder and Edwards 2001). In order to gain accurate back-calculated length at age data gained from fisheries surveys, an appropriate method of back-calculation was sought. A number of back-calculation methods were found from the literature and applied to data from fish surveys. Back-calculated lengths at age from specific cohorts were compared to observed mean lengths at age from historic surveys, revealing the method proposed by Hile (1941) as being the most consistent method for providing accurate length at age data from fisheries surveys.Comparative assessments of population mean growth rates remain important aspects of stock assessment in river fisheries (Britton 2007). Standard growth curves were originally produced for roach, dace, chub and bream (Hickley and Dexter 1979) and later expanded to include pike (Hickley and Sutton 1984). Habitat rehabilitation (Quinn 1994) and water quality improvements (Environment Agency 2001; 2006) are among a number of factors that have changed in rivers since the inception of the standard growth curves. Comparison of standard growth curves produced in this study and those produced by Britton (2007) against the original growth standards affirm the suggestion that the observed growth of these species has changed. Standard growth curves were produced and proposed for use as an updated comparative data set and an update to these standard growth rates is made on a regular basis.Riverine fish communities are highly structured and follow non-random patterns along a longitudinal profile (Jackson et al. 2001). Plasticity in the growth of fish along the longitudinal gradient of rivers has been demonstrated (Cowx 1988; Zelt et al. 1999). This study affirms the longitudinal plasticity in the growth of roach, dace and chub along the longitudinal gradient and reveals areas where conditions are conducive to better growth in these species, namely the downstream areas for roach and the upstream areas for dace and chub. Many studies have demonstrated growth rates as being dependent on geographical variation (Pyron 1999), with evidence that some fish species attain larger sizes at lower latitudes (Modde and Scalet 1985) while other studies demonstrate increased growth at higher latitudes (Isley et al. 1987, Conover and Present 1990). Latitudinal variation of fish growth characteristics from rivers throughout England and Wales revealed the growth rate of dace as being strongly related to latitudinal position, with the growth of dace showing a preference toward the cooler temperatures in the higher latitudes. Roach were found to prefer the lower latitudes where temperatures were higher, while chub were found to prefer the high latitudes and easterly longitudes.The year class strength of fish is an important index in the management of freshwater fisheries (Cowx and Frear 2004) with early developmental stages representing a crucial period in cyprinid fishes where variations in mortality during this period are critical in determining year class strength (Cowx 2001). A number of specific periods, where elevated flows occurred, were found to be related to the year class strengths of roach, dace and chub and identified as being important in playing a role in determining year class strength. The Gulf Stream was demonstrated as having a relationship with the flow regimes of a number of rivers which in-turn related to variances observed in the year class strengths and mean lengths at the end of the first year of life, of the fish species analysed. Northerly shifts in the Gulf Stream were found to have a positive influence in the growth characteristics and consequently the year class strengths in a number of the populations tested. A lag phase in the influence of the Gulf Stream on year class strengths was also identified in roach, dace and chub from a number of rivers. In this instance it was postulated that northerly shifts in the Gulf Stream produced conditions conducive to the growth of the adult fish stock which may in turn relate to an increased fecundity and/or the production of higher quality gametes from an increased condition of the adult stock