2,089 research outputs found

    Effects of the trawling ban on the diversity of demersal crustaceans (orders: decapoda and stomatopoda) in the marine environment of Hong Kong, South China

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    Oral PresentationFisheries & Marine Resources ManagementBottom trawling has been demonstrated to be one of the most destructive fishing methods to marine benthic communities. Since the 1970s, marine fishery resources in Hong Kong, especially large predatory species, have been overexploited by non-selective fishing gears including bottom and pelagic trawlers. This fishing down the trophic level has resulted in a benthic ecosystem primarily dominated by small herbivorous and omnivorous fishes and crustaceans. To mitigate such impacts, the Government of the Hong Kong Special Administrative Region has implemented a territory-wide trawling ban in local waters since 31 December 2012. This study aims to investigate whether crustacean resources, in particular of the orders Decapoda and ...postprin

    Your Proof Fails? Testing Helps to Find the Reason

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    Applying deductive verification to formally prove that a program respects its formal specification is a very complex and time-consuming task due in particular to the lack of feedback in case of proof failures. Along with a non-compliance between the code and its specification (due to an error in at least one of them), possible reasons of a proof failure include a missing or too weak specification for a called function or a loop, and lack of time or simply incapacity of the prover to finish a particular proof. This work proposes a new methodology where test generation helps to identify the reason of a proof failure and to exhibit a counter-example clearly illustrating the issue. We describe how to transform an annotated C program into C code suitable for testing and illustrate the benefits of the method on comprehensive examples. The method has been implemented in STADY, a plugin of the software analysis platform FRAMA-C. Initial experiments show that detecting non-compliances and contract weaknesses allows to precisely diagnose most proof failures.Comment: 11 pages, 10 figure

    Feedback Stabilization of a Class of Diagonal Infinite-Dimensional Systems with Delay Boundary Control

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    This paper studies the boundary feedback stabilization of a class of diagonal infinite-dimensional boundary control systems. In the studied setting, the boundary control input is subject to a constant delay while the open loop system might exhibit a finite number of unstable modes. The proposed control design strategy consists in two main steps. First, a finite-dimensional subsystem is obtained by truncation of the original Infinite-Dimensional System (IDS) via modal decomposition. It includes the unstable components of the infinite-dimensional system and allows the design of a finite-dimensional delay controller by means of the Artstein transformation and the pole-shifting theorem. Second, it is shown via the selection of an adequate Lyapunov function that 1) the finite-dimensional delay controller successfully stabilizes the original infinite-dimensional system; 2) the closed-loop system is exponentially Input-to-State Stable (ISS) with respect to distributed disturbances. Finally, the obtained ISS property is used to derive a small gain condition ensuring the stability of an IDS-ODE interconnection.Comment: Preprin

    Elucidating the food web structure of demersal crustaceans in Hong Kong's coastal water using stable isotope analysis

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    Fisheries & Marine Resources ManagementPoster presentation: P-47Bottom trawling has been demonstrated to be one of the most destructive fishing methods to marine benthic communities. Since the 1970s, marine fishery resources in Hong Kong, especially large predatory species, have been overexploited by nonselective fishing gears including bottom and pelagic trawlers. This fishing down the trophic level has resulted in a benthic ecosystem primarily dominated by small herbivorous and omnivorous fishes and crustaceans. To mitigate such impacts, the Government of the Hong Kong Special Administrative Region has implemented a territory-wide trawling ban in local waters since 31 December 2012. This study aims to investigate whether crustacean resources, in ...postprin

    Effects of the trawling ban on demersal fish communities in the marine environment of Hong Kong, South China

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    Oral PresentationFisheries & Marine Resources ManagementFishery resources in Hong Kong have been over-exploited since the 1970s. In 2010, there were still around 400 trawlers operating in local waters. These trawlers nonselectively catch marine organisms of all sizes, while exerting severe physical damage to the benthic ecosystem. To mitigate the associated impacts of overfishing and trawling, the Government of the Hong Kong Special Administrative Region has imposed a territory-wide trawling ban across local marine waters since 31 December 2012. This study aims to investigate if the trawl-ban policy is effective to facilitate recovery of demersal fish resources, in terms of species diversity, abundance and biomass, in Hong Kong. Under an approved scientific permit, trawl surveys were conducted using a commercial shrimp trawler in eastern (EW), western (WW) and southern waters (SW) of Hong Kong from ...postprin

    Spatial variation in trophic structure of Demersal Fish Communities in the marine environment of Hong Kong, South China

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    Poster presentation: P-55Fisheries & Marine Resources ManagementHong Kong’s western coastal waters (WW) situated at the Pearl River Estuary are heavily influenced by freshwater and sediment discharges from the Pearl River, while its eastern waters (EW) are mainly affected by oceanic and tidal currents. The southern waters (SW) are positioned along this estuarine-oceanic salinity gradient. Such variations in hydrography and salinity drive differences in trophic structure in local marine ecosystems. This study aimed to investigate the spatial variation in trophic structure of six demersal fish communities in WW (inner and outer estuary), EW (inner and outer Tolo Channel) and SW (waters in southeast and around Lamma). Stable isotopic ratios of δ13C and δ15N of all benthic fishes caught in trawl surveys during July-September and ...postprin

    Children and older adults exhibit distinct sub-optimal cost-benefit functions when preparing to move their eyes and hands

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    "© 2015 Gonzalez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited"Numerous activities require an individual to respond quickly to the correct stimulus. The provision of advance information allows response priming but heightened responses can cause errors (responding too early or reacting to the wrong stimulus). Thus, a balance is required between the online cognitive mechanisms (inhibitory and anticipatory) used to prepare and execute a motor response at the appropriate time. We investigated the use of advance information in 71 participants across four different age groups: (i) children, (ii) young adults, (iii) middle-aged adults, and (iv) older adults. We implemented 'cued' and 'non-cued' conditions to assess age-related changes in saccadic and touch responses to targets in three movement conditions: (a) Eyes only; (b) Hands only; (c) Eyes and Hand. Children made less saccade errors compared to young adults, but they also exhibited longer response times in cued versus non-cued conditions. In contrast, older adults showed faster responses in cued conditions but exhibited more errors. The results indicate that young adults (18 -25 years) achieve an optimal balance between anticipation and execution. In contrast, children show benefits (few errors) and costs (slow responses) of good inhibition when preparing a motor response based on advance information; whilst older adults show the benefits and costs associated with a prospective response strategy (i.e., good anticipation)

    Distributed Fine-Grained Traffic Speed Prediction for Large-Scale Transportation Networks based on Automatic LSTM Customization and Sharing

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    Short-term traffic speed prediction has been an important research topic in the past decade, and many approaches have been introduced. However, providing fine-grained, accurate, and efficient traffic-speed prediction for large-scale transportation networks where numerous traffic detectors are deployed has not been well studied. In this paper, we propose DistPre, which is a distributed fine-grained traffic speed prediction scheme for large-scale transportation networks. To achieve fine-grained and accurate traffic-speed prediction, DistPre customizes a Long Short-Term Memory (LSTM) model with an appropriate hyperparameter configuration for a detector. To make such customization process efficient and applicable for large-scale transportation networks, DistPre conducts LSTM customization on a cluster of computation nodes and allows any trained LSTM model to be shared between different detectors. If a detector observes a similar traffic pattern to another one, DistPre directly shares the existing LSTM model between the two detectors rather than customizing an LSTM model per detector. Experiments based on traffic data collected from freeway I5-N in California are conducted to evaluate the performance of DistPre. The results demonstrate that DistPre provides time-efficient LSTM customization and accurate fine-grained traffic-speed prediction for large-scale transportation networks.Comment: 14 pages, 7 figures, 2 tables, Euro-par 2020 conferenc

    Non-destructive analysis of sucrose, caffeine and trigonelline on single green coffee beans by hyperspectral imaging

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    Hyperspectral imaging (HSI) is a novel technology for the food sector that enables rapid non-contact analysis of food materials. HSI was applied for the first time to whole green coffee beans, at a single seed level, for quantitative prediction of sucrose, caffeine and trigonelline content. In addition, the intra-bean distribution of coffee constituents was analysed in Arabica and Robusta coffees on a large sample set from 12 countries, using a total of 260 samples. Individual green coffee beans were scanned by reflectance HSI (980–2500 nm) and then the concentration of sucrose, caffeine and trigonelline analysed with a reference method (HPLC-MS). Quantitative prediction models were subsequently built using Partial Least Squares (PLS) regression. Large variations in sucrose, caffeine and trigonelline were found between different species and origin, but also within beans from the same batch. It was shown that estimation of sucrose content is possible for screening purposes (R2 = 0.65; prediction error of ~ 0.7% w/w coffee, with observed range of ~ 6.5%), while the performance of the PLS model was better for caffeine and trigonelline prediction (R2 = 0.85 and R2 = 0.82, respectively; prediction errors of 0.2 and 0.1%, on a range of 2.3 and 1.1% w/w coffee, respectively). The prediction error is acceptable mainly for laboratory applications, with the potential application to breeding programmes and for screening purposes for the food industry. The spatial distribution of coffee constituents was also successfully visualised for single beans and this enabled mapping of the analytes across the bean structure at single pixel level
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