11,295 research outputs found
Integrated optimisation for production capacity, raw material ordering and production planning under time and quantity uncertainties based on two case studies
Abstract This paper develops a supply chain (SC) model by integrating raw material ordering and production planning, and production capacity decisions based upon two case studies in manufacturing firms. Multiple types of uncertainties are considered; including: time-related uncertainty (that exists in lead-time and delay) and quantity-related uncertainty (that exists in information and material flows). The SC model consists of several sub-models, which are first formulated mathematically. Simulation (simulation-based stochastic approximation) and genetic algorithm tools are then developed to evaluate several non-parameterised strategies and optimise two parameterised strategies. Experiments are conducted to contrast these strategies, quantify their relative performance, and illustrate the value of information and the impact of uncertainties. These case studies provide useful insights into understanding to what degree the integrated planning model including production capacity decisions could benefit economically in different scenarios, which types of data should be shared, and how these data could be utilised to achieve a better SC system. This study provides insights for small and middle-sized firm management to make better decisions regarding production capacity issues with respect to external uncertainty and/or disruptions; e.g. trade wars and pandemics.</jats:p
Squashed entanglement for multipartite states and entanglement measures based on the mixed convex roof
New measures of multipartite entanglement are constructed based on two
definitions of multipartite information and different methods of optimizing
over extensions of the states. One is a generalization of the squashed
entanglement where one takes the mutual information of parties conditioned on
the state's extension and takes the infimum over such extensions. Additivity of
the multipartite squashed entanglement is proved for both versions of the
multipartite information which turn out to be related. The second one is based
on taking classical extensions. This scheme is generalized, which enables to
construct measures of entanglement based on the {\it mixed convex roof} of a
quantity, which in contrast to the standard convex roof method involves
optimization over all decompositions of a density matrix rather than just the
decompositions into pure states. As one of the possible applications of these
results we prove that any multipartite monotone is an upper bound on the amount
of multipartite distillable key. The findings are finally related to analogous
results in classical key agreement.Comment: improved version, 13 pages, 1 figur
Robustness and Generalizability of Deepfake Detection: A Study with Diffusion Models
The rise of deepfake images, especially of well-known personalities, poses a
serious threat to the dissemination of authentic information. To tackle this,
we present a thorough investigation into how deepfakes are produced and how
they can be identified. The cornerstone of our research is a rich collection of
artificial celebrity faces, titled DeepFakeFace (DFF). We crafted the DFF
dataset using advanced diffusion models and have shared it with the community
through online platforms. This data serves as a robust foundation to train and
test algorithms designed to spot deepfakes. We carried out a thorough review of
the DFF dataset and suggest two evaluation methods to gauge the strength and
adaptability of deepfake recognition tools. The first method tests whether an
algorithm trained on one type of fake images can recognize those produced by
other methods. The second evaluates the algorithm's performance with imperfect
images, like those that are blurry, of low quality, or compressed. Given varied
results across deepfake methods and image changes, our findings stress the need
for better deepfake detectors. Our DFF dataset and tests aim to boost the
development of more effective tools against deepfakes.Comment: 8 pages, 5 figure
Guidance Law Design for a Class of Dual-Spin Mortars
To minimize the cost and maximize the ease of use, a class of dual-spin mortars is designed which only rely on GPS receiver and geomagnetic measurements. However, there are some problems to be solved when the range is small, such as low correction authority and trajectory bending. Guidance law design for this mortar is detailed. Different guidance laws were designed for the ascending and descending segments, respectively. By taking variable parameter guidance law in the vertical plane and using compensation in the lateral plane, the problems mentioned above were resolved. Roll angle resolving algorithms with geomagnetic measurements were demonstrated and the experiment results proved to be effective. In order to verify the effectiveness, Seven-Degrees-of-Freedom (7-DOF) rigid ballistic model were established and hardware in the loop simulation was introduced. After the transform function of the actuator was obtained, the control model of the shell was improved. The results of the Monte Carlo simulation demonstrate that the guidance law is suitable and the mortar can be effectively controlled
Using Knowledge-based Information Systems to Support Management of Wireless Sensor Networking Systems
Currently, researches on Wireless Sensor Networks (WSN) mainly focus on how to efficiently gather sensing data from WSN, but little attention has been paid to how to effectively manage the large amount of collected sensing data. Information Systems (IS) are appropriatetools for data input, storage, processing, and output. Knowledge Management (KM) further transforms useful information into domain knowledge for decision making by domain experts. In this paper, we propose an approach to management of sensing data and transformation of sensing data into valuable knowledge using knowledge-based information systems. Firstly we propose a frameworkfor knowledge-based information systems which deals with internal and external information using intelligent agents to generate domain knowledge with KM methods. Then we definite a model of knowledge-based information system for WSN to implement intensive sensing data storage, knowledge discovery, statistical analysis, sharing, inquiry, decision support. Finally, a prototype system is developed and tested for the aforementioned ideas
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