Concordia University Montreal

Computational Pathology (CPath) is an interdisciplinary science that augments developments of computational approaches to analyze and model medical histopathology images. The main objective for CPath is to develop infrastructure and workflows of digital diagnostics as an assistive CAD system for clinical pathology, facilitating transformational changes in the diagnosis and treatment of cancer that are mainly address by CPath tools. With evergrowing developments in deep learning and computer vision algorithms, and the ease of the data flow from digital pathology, currently CPath is witnessing a paradigm shift. Despite the sheer volume of engineering and scientific works being introduced for cancer image analysis, there is still a considerable gap of adopting and integrating these algorithms in clinical practice. This raises a significant question regarding the direction and trends that are undertaken in CPath. In this article we provide a comprehensive review of more than 800 papers to address the challenges faced in problem design all-the-way to the application and implementation viewpoints. We have catalogued each paper into a model-card by examining the key works and challenges faced to layout the current landscape in CPath. We hope this helps the community to locate relevant works and facilitate understanding of the field’s future directions. In a nutshell, we oversee the CPath developments in cycle of stages which are required to be cohesively linked together to address the challenges associated with such multidisciplinary science. We overview this cycle from different perspectives of data-centric, model-centric, and application-centric problems. We finally sketch remaining challenges and provide directions for future technical developments and clinical integration of CPath. For updated information on this survey review paper and accessing to the original model cards repository, please refer to GitHub. Updated version of this draft can also be found from arXiv.

A novel wideband dual-sense circularly polarized (CP) helical array antenna with enhanced isolation is proposed for the C-band satellite applications. The left-handed CP (LHCP) and the right-handed CP (RHCP) radiation in the same band are realized by using two concentric helical antennas with different radii and winding directions for the first time. The parameters of the two concentric helical antennas are investigated in detail to enable them to operate in the same frequency range while maintaining good CPs performance. To achieve a high isolation between the two nested helical antenna, the parameters, such as the number of turns, pitches, and offset rotation angles of the two helical antennas are studied. Then, a 2  2 dual-sense CP helical array antenna is developed by applying two sequentially rotated microstrip feeding networks on the same plane. To alleviate the congestion, the two feeding networks with 90-degree and 270-degree phase gradients are placed concentrically to excite RHCP and LHCP radiation, respectively. The dual-sense CP helical array antenna is prototyped and verified experimentally. Measured results agree well with the simulations, showing a wide overlapped impedance/3dB-AR bandwidth from 3.7-5.0 GHz (FBW = 30%) for both polarizations. The isolation is better than 22 dB over the frequency range.

Rural passive distribution networks can no longer meet the modern agricultural electrification and cleanliness requirements, and it is urgent to carry out distributed energy planning construction in rural areas. This paper studies the theoretical and methodological aspects of distributed energy planning in rural areas considering crop growth mechanisms. In light of the effects of agricultural load control on agricultural production, we have created a facility-based agricultural load control model rooted in crop physiological ecology. The proposed model encompasses electric irrigation, high-pressure sodium lighting and heating loads. In response to the impact of agricultural load control on carbon emissions in the energy system, carbon cycling within the agricultural and energy systems has been analyzed and modeled. Considering the significant differences in greenhouse load requirements at different growth stages of different crops, the distributed energy planning model is established based on representative daily profiles that reflect typical crop growth patterns. The proposed model constraints encompass constraints related to the healthy growth of crops and constraints within the energy system, with the optimization goal set to minimize the 15-year planning cost. We validate the planning model by applying it to a case study involving a rural energy system in Hebei Province, China, with an annual electricity consumption of 5,600,376 kWh. The adoption of this model led to a cost reduction of 7.3 ×105 CNY compared to conventional planning methods. The collaborative synergy between agriculture, energy, and the environment manifested in an annual carbon reduction benefit (ACRB) of 1.7×104CNY from photovoltaic generation and an ACRB of 1.2×104 CNY from greenhouse gas absorption.

This paper deals with the reachable set synthesis problem for discrete-time periodic piecewise systems (PPSs) subject to multiple packet dropouts and bounded-peak disturbances. Firstly, the multiple packet dropout scenario is formulated by using two mutually independent binary variables satisfying a Bernoulli distribution. Then, a novel Lyapunov function related to the control matrix information is constructed to develop the periodic state feedback controller in the observer framework. The proposed controller can ensure the stability and reachability of the closed-loop system in the mean-square sense. For the sake of calculations, the singular value decomposition (SVD) condition is employed to design the observer and controller, thereby transforming into a convex programming problem with linear matrix inequality (LMI) constraints. Moreover, an index optimizing the bounding region of the desirable reachable set is given via resorting to the ellipsoid technique, and their results are compared. Finally, numerical examples are given to validate the effectiveness of the proposed theoretical results.

This study proposes a novel control scheme for simultaneously tracking and stabilizing nonholonomic wheeled mobile robots (NWMRs) subject to actuator and sensor faults, measurement errors, uncertain dynamics, and time-varying slippage/skid disturbances. To this end, a nonlinear model based on a type-3 (T3) fuzzy logic system (FLS) is developed for NWMR tracking and stabilization. Furthermore, a nonlinear model predictive controller (NMPC) is designed analytically without employing iterative computations, thus achieving fast performance. A new approach of type-3 nonsingleton fuzzification is introduced to handle measurement errors. Additionally, faults in the actuators and sensors are detected by a supervisory scheme and eliminated by a devised compensator. Finally, extensive simulations and experimental validations are conducted to further verify the effectiveness of the proposed scheme, along with a comparative analysis of several benchmarking methods.

With the growth of smart systems and applications, high volume logs are generated that record important data for system maintenance. System developers are usually required to analyze logs to track the status of the system or applications. Therefore, it is essential to find the answers in large-scale logs when they have some questions. In this work, we design a multi-step “ Retriever-Reader “ question-answering system, namely LogSay, which aims at predicting answers accurately and efficiently. Our system can not only answers simple questions, such as a segment log or span, but also can answer complex logical questions through numerical reasoning. LogSay has two key components: Log Retriever and Log Reasoner , and we designed five operators to implement them. Log Retriever aims at retrieving some relevant logs based on a question. Then, Log Reasoner performs numerical reasoning to infer the final answer. In addition, due to the lack of available question-answering datasets for system logs, we constructed question-answering datasets based on three public log datasets and will make them publicly available. Our evaluation results show that LogSay outperforms the state-of-the-art works in terms of accuracy and efficiency.

Container–based microservice provisioning, with its elasticity in terms of the layered structure, enables the sharing of common layers among different edge computing tasks, both within and across edge servers (ES). However, due to the potential hardware breakdowns, each ES may prone to failures, affecting its lifetime (i.e., the time-length that an ES works continuously without interruptions), and in turn leading to the collapse of their hosted/provided microservices or the other ESs’ microservices requesting common layers from it. To address such an issue, in this paper, we study the microservice deployment optimization with layer sharing for maximizing the system-wide reliability while satisfying all tasks’ delay requirements. Considering dynamic task generations and the asynchronization of various decision variables with different triggers, we design an online optimization algorithm by leveraging an improved Lyapunov technique integrating randomized rounding, Lagrangian method and convex optimization, which iteratively solves the problem over different timescales. Theoretical analyses and simulations evaluate the performance of the proposed solution, showing that it can achieve an increase of 12.4% in reliability and a reduction of 28.57% in total delay, compared to the counterparts.

What happens to cellphilm archives produced in participatory visual research projects after the projects end? This chapter reflexively revisits three YouTube-based cellphilm archives one from Hong Kong (2015) and two from New Brunswick, Canada (2020, 2021) and suggests that although theorized as participatory, the three examples of archives explored in the chapter don’t quite do what I had set out for them to do. And yet, they offer something for participatory researchers interested in archiving and exhibition over time to think about in relation to the curatorial function of the participatory researcher, and how the archive remains and might be audienced beyond the scope of the project. These are important considerations as we think about what to do with the cellphilm archives that emerge from a project over longer periods of time.

Semantic memory representations are generally well maintained in aging, whereas semantic control is thought to be more affected. To explain this phenomenon, this study tested the predictions of the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), focusing on task demands in aging as a possible framework. The CRUNCH effect would manifest itself in semantic tasks through a compensatory increase in neural activation in semantic control network regions but only up to a certain threshold of task demands. This study compares 39 younger (20–35 years old) with 39 older participants (60–75 years old) in a triad-based semantic judgment task performed in an fMRI scanner while manipulating task demand levels (low versus high) through semantic distance. In line with the CRUNCH predictions, differences in neurofunctional activation and behavioral performance (accuracy and response times) were expected in younger versus older participants in the low- versus high-demand conditions, which should be manifested in semantic control Regions of Interest (ROIs). Our older participants had intact behavioral performance, as proposed in the literature for semantic memory tasks (maintained accuracy and slower response times (RTs)). Age-invariant behavioral performance in the older group compared to the younger one is necessary to test the CRUNCH predictions. The older adults were also characterized by high cognitive reserve, as our neuropsychological tests showed. Our behavioral results confirmed that our task successfully manipulated task demands: error rates, RTs and perceived difficulty increased with increasing task demands in both age groups. We did not find an interaction between age group and task demand, or a statistically significant difference in activation between the low- and high-demand conditions for either RTs or accuracy. As for brain activation, we did not find the expected age group by task demand interaction, or a significant main effect of task demand. Overall, our results are compatible with some neural activation in the semantic network and the semantic control network, largely in frontotemporoparietal regions. ROI analyses demonstrated significant effects (but no interactions) of task demand in the left and right inferior frontal gyrus, the left posterior middle temporal gyrus, the posterior inferior temporal gyrus and the prefrontal gyrus. Overall, our test did not confirm the CRUNCH predictions.

In this paper, we consider an alternative parametrization of Dirichlet Compound Negative Multinomial (DCNM) using rising polynomials. The new parametrization gets rid of Gamma functions and allows us to derive the Exact Fisher Information Matrix, which brings significant improvements to model performance due to feature correlation consideration. Second, we propose to improve the computation efficiency by approximating the DCNM model as a member of the exponential family of distributions, called EDCNM. The novel EDCNM model brings several advantages as compared to the DCNM model, such as a closed-form solution for maximum likelihood estimation, higher efficiency due to computational time reduction for sparse datasets, etc. Third, we implement Agglomerative Hierarchical clustering, where Kullback–Leibler divergence is derived and used to measure the distance between two EDCNM probability distributions. Finally, we integrate the Minimum Message Length criterion in our algorithm to estimate the optimal number of components of the mixture model. The merits of our proposed models are validated via challenging real-world applications in Natural Language Processing and Image/Video Recognition. Results reveal that the exponential approximation of the DCNM model has reduced significantly the computational complexity in high-dimensional feature spaces.

Climate adaptation policy in Canada is emerging in the context of another major challenge: the diminishing availability of affordable housing. Housing is a well‐known driver of social vulnerability to environmental risks, so as governments respond to these challenges, it will be essential to understand how housing is being situated within adaptation, particularly with respect to differences in housing tenure and how decisions around equity and social vulnerability are factored into planning and policy processes. This research examines how adaptation plans and policies in Nova Scotia are addressing the needs of the non‐profit co‐operative housing sector and assesses the adaptation readiness of housing co‐operatives in the province. Two methods are employed: a systematic content analysis of municipal and provincial climate policy documents, and interviews with key informants across the co‐operative housing sector and government agencies. Using a modified adaptation readiness framework, we consider the potential for co‐operative adaptation and complimentary public policy to address vulnerability at the intersection of housing and climate change. Findings indicate that non‐market forms of tenure have been largely neglected by adaptation planners and state policymakers. Several barriers which contribute to a low level of adaptation readiness for co‐ops are highlighted, notably a lack of usable science and funding to facilitate adaptation. Characteristics such as affordability and a propensity for collective action position housing co‐ops to be agents of equitable and systemic adaptation, but this potential will only be realized in Canada if key barriers are overcome through targeted governmental rt for non‐profit housing organizations.

Dye‐sensitized photoelectrochemical cells can enable the production of molecules currently accessible through energetically demanding syntheses. Copper(I)‐based dyes represent electronically tunable charge transfer and separation systems. Herein, we report a Cu(I)‐bisdiimine donor‐chromophore‐acceptor dye with an absorbance in the visible part of the solar spectrum composed of a phenothiazine electron donor, and dipyrido[3,2‐a:2′,3′‐c]phenazine electron acceptor. This complex is incorporated onto a zinc oxide nanowire semiconductor surface effectively forming a photoanode that is characterized spectroscopically and electrochemically. We investigate the photo‐oxidation of hydroquinone, and the photosensitization of 2,2,6,6‐tetramethylpiperidine‐1‐oxyl and N‐hydroxyphthalimide for the oxidation of furfuryl alcohol to furfuraldehyde, resulting in near quantitative conversions, with poor selectivity to the alcohol.

Background Hearing impairments are a rising burden in our aging society. Hearing loss is associated with reduced cognitive performance as well as decrements in balance and gait. Therefore, impaired hearing affects also dual tasking (DT). The aim of this review is to summarize the evidence for DT performance decrements of older adults with hearing impairments during maintaining balance or walking. Methods The systematic literature research according to PRISMA guidelines was conducted using MEDLINE, APA Psych-Info, and Web of Science. Inclusion criteria were: Independent living older people ≥ 60 years with hearing impairments, use of a DT paradigm to test hearing impaired older adults within a balance or walking condition. Results N = 57 studies were found within the databases. Eight studies were included ( N = 456 participants (58% women), including n = 200 older hearing-impaired persons with different levels of hearing loss). Most of the included studies oriented their inclusion criteria for hearing-impairments at thresholds for mild hearing loss with Pure Tone Average (0.5-4 kHz) ≥ 25 and < 40 dB. Three of the studies focused on DT balance performance and five used DT walking comparing participants with and without hearing loss. For DT balance and gait performance, higher decrements for the hearing-impaired group were observed compared to healthy older adults. Performance decrements were accompanied by reduced compensatory strategies in balance performance. Conclusion More pronounced decrements in DT performance were observed for participants with hearing impairments compared to those without. This implies that hearing-impaired older adults might need specific interventions to reduce the cognitive-motor interference (CMI) to maintain balance control or walking stability in daily situations that require managing of cognitive and motor tasks simultaneously. However, taking all results into account the underlying mechanisms of CMI for this target group needs to be further examined. Trial registration This review was registered at Prospero with the ID CRD42022340232.

A process employing extrusion was used to produce multicore microcapsules composed of multiple beads. The inner beads were made from κ-carrageenan (κ-c), a thermo-responsive linear sulphated polymer whose gelling temperature ranges at 40–60 °C, depending on the concentration of κ-c polymer and the amount of potassium chloride used for gelation. The resulting beads were then enveloped by chitosan through gelation with sodium triphosphate. The pesticide ammonium glufosinate was encapsulated in the κ-c/chitosan multicore microcapsules for demonstration of controlled release of the encapsulant. It was found that in response to an external stimulus, such as elevated temperature or solar simulation, the microcapsules exhibit the gradual release of encapsulated pesticide molecules from multicore microcapsules, compared with beads only. This process of making multicore microcapsules can be extended to other polymer pairs based on applications. This work is relevant to agriculture, where the controlled-release of the pesticides or fertilizers could be triggered by the sun and/or temperature changes, thus extending the residual period of the chemicals as well as decreasing the extent of pollution by leaching of abundant chemicals.

While the influence of dispersal on ecological selection is the subject of intense research, we still lack a thorough understanding of how ecological selection operates to favour distinct dispersal strategies in metacommunities. To address this issue, we developed a model framework in which species with distinct quantitative dispersal traits that govern the three stages of dispersal—departure, movement and settlement—compete under different ecological contexts. The model identified three primary dispersal strategies (referred to as nomadic, homebody and habitat-sorting) that consistently dominated metacommunities owing to the interplay of spatiotemporal environmental variation and different types of competitive interactions. We outlined the key characteristics of each strategy and formulated theoretical predictions regarding the abiotic and biotic conditions under which each strategy is more likely to prevail in metacommunities. By presenting our results as relationships between dispersal traits and well-known ecological gradients (e.g. seasonality), we were able to contrast our theoretical findings with previous empirical research. Our model demonstrates how landscape environmental characteristics and competitive interactions at the intra- and interspecific levels can interact to favour distinct multivariate and context-dependent dispersal strategies in metacommunities. This article is part of the theme issue ‘Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics’.

This study examines the role of growth opportunities on stock buybacks and provides evidence on the importance of signaling and agency theories in explaining stock buybacks. Both theories are required to fully explain stock buybacks. As per the signaling theory, we find that the announcement period returns are positive for stock buybacks, which indicates that the buyback firms’ stock is undervalued. Furthermore, consistent with agency theory, we also find that the announcement period returns are higher for firms with low growth opportunities and high free cash flow. We also examine buyback firms' long-run stock price performance for 12 months, 24 months, and 36 months following the buyback. We use the Fama–French five-factor model to study the long-run stock performance of buyback firms because of its better explanatory power than the three-factor model. Low growth-high free cash flow firms tend to outperform their benchmark portfolios during this period. Recent regulations such as the Stock Buyback Tax can discourage low growth firms from conducting stock buybacks, which could increase agency costs.

Methyl mercury, a toxic compound, is produced by anaerobic microbes and magnifies in aquatic food webs, affecting the health of animals and humans. The exploration of mercury methylators based on genomes is still limited, especially in the context of river ecosystems. To address this knowledge gap, we developed a genome catalogue of potential mercury‐methylating microorganisms. This was based on the presence of hgcAB from the sediments of a river affected by two run‐of‐river hydroelectric dams, logging activities and a wildfire. Through the use of genome‐resolved metagenomics, we discovered a unique and diverse group of mercury methylators. These were dominated by members of the metabolically versatile Bacteroidota and were particularly rich in microbes that ferment butyrate. By comparing the diversity and abundance of mercury methylators between sites subjected to different disturbances, we found that ongoing disturbances, such as the input of organic matter related to logging activities, were particularly conducive to the establishment of a mercury‐methylating niche. Finally, to gain a deeper understanding of the environmental factors that shape the diversity of mercury methylators, we compared the mercury‐methylating genome catalogue with the broader microbial community. The results suggest that mercury methylators respond to environmental conditions in a manner similar to the overall microbial community. Therefore, it is crucial to interpret the diversity and abundance of mercury methylators within their specific ecological context.

Intergroup aggression often results in the production of public goods, such as a safe and stable social environment and a home range containing the resources required to survive and reproduce. We investigate temporal variation in intergroup aggression in a growing population of colobus monkeys (Colobus vellerosus) to ask a novel question: “Who stepped-up to produce these public goods when doing so became more difficult?”. Both whole-group encounters and male incursions occurred more frequently as the population grew. Males and females were both more likely to participate in whole-group encounters when monopolizable food resources were available, indicating both sexes engaged in food defence. However, only females increasingly did so as the population grew, suggesting that it was females who increasingly produced the public good of home range defence as intergroup competition intensified. Females were also more active in male incursions at high population densities, suggesting they increasingly produced the public good of a safe and stable social environment. This is not to say that males were chronic free-riders when it came to maintaining public goods. Males consistently participated in the majority of intergroup interactions throughout the study period, indicating they may have lacked the capacity to invest more time and effort.