761,332 research outputs found
Strategies for dynamic appointment making by container terminals
We consider a container terminal that has to make appointments with barges dynamically, in real-time, and partly automatic. The challenge for the terminal is to make appointments with only limited knowledge about future arriving barges, and in the view of uncertainty and disturbances, such as uncertain arrival and handling times, as well as cancellations and no-shows. We illustrate this problem using an innovative implementation project which is currently running in the Port of Rotterdam. This project aims to align barge rotations and terminal quay schedules by means of a multi-agent system. In this\ud
paper, we take the perspective of a single terminal that will participate in this planning system, and focus on the decision making capabilities of its intelligent agent. We focus on the question how the terminal operator can optimize, on an operational level, the utilization of its quay resources, while making reliable appointments with barges, i.e., with a guaranteed departure time. We explore two approaches: (i) an analytical approach based on the value of having certain intervals within the schedule and (ii) an approach based on sources of exibility that are naturally available to the terminal. We use simulation to get insight in the benefits of these approaches. We conclude that a major increase in utilization degree could be achieved only by deploying the sources of exibility, without harming the waiting time of barges too much
An overview of Space Communication Artificial Intelligence for Link Evaluation Terminal (SCAILET) Project
A software application to assist end-users of the link evaluation terminal (LET) for satellite communications is being developed. This software application incorporates artificial intelligence (AI) techniques and will be deployed as an interface to LET. The high burst rate (HBR) LET provides 30 GHz transmitting/20 GHz receiving (220/110 Mbps) capability for wideband communications technology experiments with the Advanced Communications Technology Satellite (ACTS). The HBR LET can monitor and evaluate the integrity of the HBR communications uplink and downlink to the ACTS satellite. The uplink HBR transmission is performed by bursting the bit-pattern as a modulated signal to the satellite. The HBR LET can determine the bit error rate (BER) under various atmospheric conditions by comparing the transmitted bit pattern with the received bit pattern. An algorithm for power augmentation will be applied to enhance the system's BER performance at reduced signal strength caused by adverse conditions
Portfolio Choice when Managers Control Returns
This paper investigates the allocation decision of an investor with two projects. Separate managers control the mean return from each project, and the investor may or may not observe the managers’ actions. We show that the investor’s risk-return trade-off may be radically different from a standard portfolio choice setting, even if managers’ actions are observable and enforceable. In particular, feedback effects working through optimal contracts and effort levels imply that expected terminal wealth is nonlinear in initial wealth allocation. The optimal portfolio may involve very little diversification, despite projects that are highly symmetric in the underlying model. We also show that moral hazard in one of the projects need not imply lower allocation to that project. Expected returns are generally lower than under the first-best, but the optimal contract shifts more of the idiosyncratic risk in the hidden action project to the manager in charge of it. The minimum-variance position of the investor’s (net) terminal wealth would in most cases involve a portfolio shift towards the hidden action project, and there are plausible cases where this would dominate the overall effect on the second-best optimal portfolio when comparing with the first-best.Portfolio choice; diversification; optimal contracts
Linux Terminal Server Project en la escuela
Este artículo contiene información sobre el proyecto LTSP (Linux Terminal Server Project) que permite aprovechar los ordenadores más antiguos para que ejecuten los programas más modernos. Gracias a este proyecto, los centros educativos podrán aumentar, sin costes, el número de aulas de informática, mejorando la ratio aulas TIC alumnado, lo que contribuirá a intensificar el uso de las TIC en educación
UAS Concept of Operations and Vehicle Technologies Demonstration
In 2017 and 2018, under National Aeronautics and Space Administration (NASA) sponsorship, the New York Unmanned Aircraft Systems (UAS) Test Site and Northeast UAS Airspace Integration Research (NUAIR) Alliance conducted a year-long research project that culminated in a UAS technology flight demonstration. The research project included the creation of a concept of operations, and development and demonstration of UAS technologies. The concept of operations was focused on an unmanned aircraft transiting from cruise through Class E airspace into a high-density urban terminal environment. The terminal environment in which the test was conducted was Griffiss International Airport, under Syracuse Air Traffic Control (ATC) approach control and Griffiss control tower. Employing an Aurora Centaur optionally piloted aircraft (OPA), this project explored six scenarios aimed at advancing UAS integration into the National Airspace System (NAS) under both nominal and off-nominal conditions. Off-nominal conditions were defined to include complete loss of the communications link between the remote pilots control station on the ground and the aircraft. The off-nominal scenarios that were investigated included lost-link conditions with and without link recovery, an automated ATC initiated go-around, autonomous rerouting around a dynamic airspace obstruction (in this case simulated weather), and autonomous taxi operations to clear the runway
Modeling an offshore container terminal: the Venice case study
In order to reduce marine transportation times and related costs, as well as the environmental impacts, an alternative multimodal route to the current Suez-Gibraltar-North Sea corridor for the containers shipped from Far and Middle East was identified as potentially very effective. A key operational problem to achieve this result is the capacity and the effectiveness of the terminals within the concerned new logistic chain. In this framework, the Venice Port Authority is developing a project aimed to improve relevantly the potential of its container terminals to al-low loading/unloading of containers to and from the Central Europe. The project includes a new offshore terminal for mooring huge ships (up to 18.000 TEU) in the Adriatic Sea and a link operated by barges with an onshore terminal in Venice to overcome the constraints for the navigation of the containers ships in the Venetian lagoon. This innovative operational scheme requires a deep functional analysis to ensure the full capacity
operation, assess the reachable performances and correspondingly dimensioning the required equipment (cranes, barges, quays, etc.). For this purpose, the authors developed a specific discrete-events simulation model. The paper includes the presentation of the model and the results of its application to Venice case study, by identifying the benefits achievable with this approach and the potential wider application fields
Computer-based communication in support of scientific and technical work
Results are reported of the first experiments for a computer conference management information system at the National Aeronautics and Space Administration. Between August 1975 and March 1976, two NASA projects with geographically separated participants (NASA scientists) used the PLANET computer conferencing system for portions of their work. The first project was a technology assessment of future transportation systems. The second project involved experiments with the Communication Technology Satellite. As part of this project, pre- and postlaunch operations were discussed in a computer conference. These conferences also provided the context for an analysis of the cost of computer conferencing. In particular, six cost components were identified: (1) terminal equipment, (2) communication with a network port, (3) network connection, (4) computer utilization, (5) data storage and (6) administrative overhead
The structure of an LIM-only protein 4 (LMO4) and deformed epidermal autoregulatory factor-1 (DEAF1) complex reveals a common mode of binding to LMO4
LIM-domain only protein 4 (LMO4) is a widely expressed protein with important roles in embryonic development and breast cancer. It has been reported to bind many partners, including the transcription factor Deformed epidermal autoregulatory factor-1 (DEAF1), with which LMO4 shares many biological parallels. We used yeast two-hybrid assays to show that DEAF1 binds both LIM domains of LMO4 and that DEAF1 binds the same face on LMO4 as two other LMO4-binding partners, namely LIM domain binding protein 1 (LDB1) and C-terminal binding protein interacting protein (CtIP/RBBP8). Mutagenic screening analysed by the same method, indicates that the key residues in the interaction lie in LMO4LIM2 and the N-terminal half of the LMO4-binding domain in DEAF1. We generated a stable LMO4LIM2-DEAF1 complex and determined the solution structure of that complex. Although the LMO4-binding domain from DEAF1 is intrinsically disordered, it becomes structured on binding. The structure confirms that LDB1, CtIP and DEAF1 all bind to the same face on LMO4. LMO4 appears to form a hub in protein-protein interaction networks, linking numerous pathways within cells. Competitive binding for LMO4 therefore most likely provides a level of regulation between those different pathways.SJ was funded by an Australian Postgraduate Award (education.gov.au/australian-postgraduate-awards). JPM and JMM were awarded Senior Research
Fellowships from the Australian National and Medical Research Council (www.nhmrc.gov.au). This project was funded by an Australian Research Council (www.
arc.gov.au) Discovery Project Grant (DP110104332) to JMM and LC
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