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1
Banerjee, Debangshu, and R. Inkulu. "Vertex Guarding for Dynamic Orthogonal Art Galleries." International Journal of Computational Geometry & Applications 31, no. 02n03 (June 2021): 123–40. http://dx.doi.org/10.1142/s0218195921500060.
Testo completoAbstract (sommario):
We devise an algorithm for surveying a dynamic orthogonal polygonal domain by placing one guard at each vertex in a subset of its vertices, i.e., whenever an orthogonal polygonal domain [Formula: see text] is modified to result in another orthogonal polygonal domain [Formula: see text], our algorithm updates the set of vertex guards surveying [Formula: see text] so that the updated guard set surveys [Formula: see text]. Our algorithm modifies the guard placement in [Formula: see text] amortized time, while ensuring the updated orthogonal polygonal domain with [Formula: see text] holes and [Formula: see text] vertices is guarded using at most [Formula: see text] vertex guards. For the special case of the initial orthogonal polygon being hole-free and each update resulting in a hole-free orthogonal polygon, our guard update algorithm takes [Formula: see text] worst-case time. Here, [Formula: see text] and [Formula: see text] are the number of vertices of the orthogonal polygon before and after the update, respectively; and, [Formula: see text] is the sum of [Formula: see text] and the number of updates to a few structures maintained by our algorithm. Further, by giving a construction, we show it suffices for the algorithm to consider only the case in which the parity of the number of reflex vertices of both [Formula: see text] and [Formula: see text] are equal.
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KOOI, BARTELD, and BRYAN RENNE. "ARROW UPDATE LOGIC." Review of Symbolic Logic 4, no. 4 (October 13, 2011): 536–59. http://dx.doi.org/10.1017/s1755020311000189.
Testo completoAbstract (sommario):
We presentArrow Update Logic, a theory of epistemic access elimination that can be used to reason about multi-agent belief change. While the belief-changing “arrow updates” of Arrow Update Logic can be transformed into equivalent belief-changing “action models” from the popular Dynamic Epistemic Logic approach, we prove that arrow updates are sometimes exponentially more succinct than action models. Further, since many examples of belief change are naturally thought of from Arrow Update Logic’s perspective of eliminating access to epistemic possibilities, Arrow Update Logic is a valuable addition to the repertoire of logics of information change. In addition to proving basic results about Arrow Update Logic, we introduce a new notion of common knowledge that generalizes both ordinary common knowledge and the “relativized” common knowledge familiar from the Dynamic Epistemic Logic literature.
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Deshmukh, Ankosh D., Nitesh D. Shambharkar, and Prashant M. Gade. "Effect of a Mode of Update on Universality Class for Coupled Logistic Maps: Directed Ising to Ising Class." International Journal of Bifurcation and Chaos 31, no. 03 (March 15, 2021): 2150042. http://dx.doi.org/10.1142/s0218127421500425.
Testo completoAbstract (sommario):
Ising model at zero temperature leads to a ferromagnetic state asymptotically. There are two such possible states linked by symmetry, and Glauber–Ising dynamics are employed to reach them. In some stochastic or deterministic dynamical systems, the same absorbing state with [Formula: see text] symmetry is reached. This transition often belongs to the directed Ising (DI) class where dynamic exponents and persistence exponent are different. In asymmetrically coupled sequentially updated logistic maps, the transition belongs to the DI class. We study changes in the nature of transition with an update scheme. Even with the synchronous update, the transition still belongs to the DI class. We also study a synchronous probabilistic update scheme in which each site is updated with the probability [Formula: see text]. The order parameter decays with an exponent [Formula: see text] in this scheme. Nevertheless, the dynamic exponent [Formula: see text] is less than [Formula: see text] even for small values of [Formula: see text] indicating a very slow crossover to the Ising class. However, with a random asynchronous update, we recover [Formula: see text]. In the presence of feedback, synchronous update leads to a transition in the DI universality class which changes to Ising class for synchronous probabilistic update.
4
SLOTA, MARTIN, and JOÃO LEITE. "Towards closed world reasoning in dynamic open worlds." Theory and Practice of Logic Programming 10, no. 4-6 (July 2010): 547–63. http://dx.doi.org/10.1017/s147106841000027x.
Testo completoAbstract (sommario):
AbstractThe need for integration of ontologies with nonmonotonic rules has been gaining importance in a number of areas, such as the Semantic Web. A number of researchers addressed this problem by proposing a unified semantics forhybrid knowledge basescomposed of both an ontology (expressed in a fragment of first-order logic) and nonmonotonic rules. These semantics have matured over the years, but only provide solutions for the static case when knowledge does not need to evolve.In this paper we take a first step towards addressing the dynamics of hybrid knowledge bases. We focus on knowledge updates and, considering the state of the art of belief update, ontology update and rule update, we show that current solutions are only partial and difficult to combine. Then we extend the existing work on ABox updates with rules, provide a semantics for such evolving hybrid knowledge bases and study its basic properties.To the best of our knowledge, this is the first time that an update operator is proposed for hybrid knowledge bases.
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Bernstein, Aaron, Sebastian Forster, and Monika Henzinger. "A Deamortization Approach for Dynamic Spanner and Dynamic Maximal Matching." ACM Transactions on Algorithms 17, no. 4 (October 31, 2021): 1–51. http://dx.doi.org/10.1145/3469833.
Testo completoAbstract (sommario):
Many dynamic graph algorithms have an amortized update time, rather than a stronger worst-case guarantee. But amortized data structures are not suitable for real-time systems, where each individual operation has to be executed quickly. For this reason, there exist many recent randomized results that aim to provide a guarantee stronger than amortized expected. The strongest possible guarantee for a randomized algorithm is that it is always correct (Las Vegas) and has high-probability worst-case update time, which gives a bound on the time for each individual operation that holds with high probability. In this article, we present the first polylogarithmic high-probability worst-case time bounds for the dynamic spanner and the dynamic maximal matching problem. (1) For dynamic spanner, the only known o ( n ) worst-case bounds were O ( n 3/4 ) high-probability worst-case update time for maintaining a 3-spanner and O ( n 5/9 ) for maintaining a 5-spanner. We give a O (1) k log 3 ( n ) high-probability worst-case time bound for maintaining a ( 2k-1 )-spanner, which yields the first worst-case polylog update time for all constant k . (All the results above maintain the optimal tradeoff of stretch 2k-1 and Õ( n 1+1/k ) edges.) (2) For dynamic maximal matching, or dynamic 2-approximate maximum matching, no algorithm with o(n) worst-case time bound was known and we present an algorithm with O (log 5 ( n )) high-probability worst-case time; similar worst-case bounds existed only for maintaining a matching that was (2+ϵ)-approximate, and hence not maximal. Our results are achieved using a new approach for converting amortized guarantees to worst-case ones for randomized data structures by going through a third type of guarantee, which is a middle ground between the two above: An algorithm is said to have worst-case expected update time ɑ if for every update σ, the expected time to process σ is at most ɑ. Although stronger than amortized expected, the worst-case expected guarantee does not resolve the fundamental problem of amortization: A worst-case expected update time of O(1) still allows for the possibility that every 1/ f(n) updates requires ϴ ( f(n) ) time to process, for arbitrarily high f(n) . In this article, we present a black-box reduction that converts any data structure with worst-case expected update time into one with a high-probability worst-case update time: The query time remains the same, while the update time increases by a factor of O (log 2(n) ). Thus, we achieve our results in two steps: (1) First, we show how to convert existing dynamic graph algorithms with amortized expected polylogarithmic running times into algorithms with worst-case expected polylogarithmic running times. (2) Then, we use our black-box reduction to achieve the polylogarithmic high-probability worst-case time bound. All our algorithms are Las-Vegas-type algorithms.
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Bernstein, Aaron, Sebastian Forster, and Monika Henzinger. "A Deamortization Approach for Dynamic Spanner and Dynamic Maximal Matching." ACM Transactions on Algorithms 17, no. 4 (October 31, 2021): 1–51. http://dx.doi.org/10.1145/3469833.
Testo completoAbstract (sommario):
Many dynamic graph algorithms have an amortized update time, rather than a stronger worst-case guarantee. But amortized data structures are not suitable for real-time systems, where each individual operation has to be executed quickly. For this reason, there exist many recent randomized results that aim to provide a guarantee stronger than amortized expected. The strongest possible guarantee for a randomized algorithm is that it is always correct (Las Vegas) and has high-probability worst-case update time, which gives a bound on the time for each individual operation that holds with high probability. In this article, we present the first polylogarithmic high-probability worst-case time bounds for the dynamic spanner and the dynamic maximal matching problem. (1) For dynamic spanner, the only known o ( n ) worst-case bounds were O ( n 3/4 ) high-probability worst-case update time for maintaining a 3-spanner and O ( n 5/9 ) for maintaining a 5-spanner. We give a O (1) k log 3 ( n ) high-probability worst-case time bound for maintaining a ( 2k-1 )-spanner, which yields the first worst-case polylog update time for all constant k . (All the results above maintain the optimal tradeoff of stretch 2k-1 and Õ( n 1+1/k ) edges.) (2) For dynamic maximal matching, or dynamic 2-approximate maximum matching, no algorithm with o(n) worst-case time bound was known and we present an algorithm with O (log 5 ( n )) high-probability worst-case time; similar worst-case bounds existed only for maintaining a matching that was (2+ϵ)-approximate, and hence not maximal. Our results are achieved using a new approach for converting amortized guarantees to worst-case ones for randomized data structures by going through a third type of guarantee, which is a middle ground between the two above: An algorithm is said to have worst-case expected update time ɑ if for every update σ, the expected time to process σ is at most ɑ. Although stronger than amortized expected, the worst-case expected guarantee does not resolve the fundamental problem of amortization: A worst-case expected update time of O(1) still allows for the possibility that every 1/ f(n) updates requires ϴ ( f(n) ) time to process, for arbitrarily high f(n) . In this article, we present a black-box reduction that converts any data structure with worst-case expected update time into one with a high-probability worst-case update time: The query time remains the same, while the update time increases by a factor of O (log 2(n) ). Thus, we achieve our results in two steps: (1) First, we show how to convert existing dynamic graph algorithms with amortized expected polylogarithmic running times into algorithms with worst-case expected polylogarithmic running times. (2) Then, we use our black-box reduction to achieve the polylogarithmic high-probability worst-case time bound. All our algorithms are Las-Vegas-type algorithms.
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Zhou, Liang, Nan Ya Cao, Lu Li, Li Xin Ke, and Kai Jun Wu. "Research on Service Update Dynamically Based on OSGi Frame." Applied Mechanics and Materials 513-517 (February 2014): 1769–72. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.1769.
Testo completoAbstract (sommario):
It is a key problem for a 7*24 running system to update and maintain online. According to the feature of OSGi (Open Service Gateway Initiative) framework, current service dynamic update policies for OSGi framework are analyzed. In order to solve the problem of service mutual consistency and service state consistency during service update, the service dynamic update policy based on publish & subscribe model is presented. This policy is based on quiescent state theory to ensure mutual consistency when services are updated online. The process of the dynamic service update policy is described by Petri net. We realize the policy using Event Admin Service in the experiment with well-defined program model. The result shows that the policy is validate and feasibility.
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Kahle, Reinhard. "Default Negation as Explicit Negation plus Update." Logical Investigations 27, no. 1 (May 27, 2021): 64–81. http://dx.doi.org/10.21146/2074-1472-2021-27-1-64-81.
Testo completoAbstract (sommario):
We argue that under the stable model semantics default negation can be read as explicit negation with update. We show that dynamic logic programming which is based on default negation, even in the heads, can be interpreted in a variant of updates with explicit negation only. As corollaries, we get an easy description of default negation in generalized and normal logic programming where initially negated literals are updated. These results are discussed with respect to the understanding of negation in logic.
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Xu, Tie, Haoran Yang, Jun Ma, Kun Xiong, and Qinyou Hu. "An Improved D* Lite-Based Dynamic Route Planning Algorithm for Ships in Arctic Waters." Journal of Marine Science and Engineering 12, no. 12 (December 18, 2024): 2323. https://doi.org/10.3390/jmse12122323.
Testo completoAbstract (sommario):
The ice conditions in Arctic waters are complex and variable, requiring ships to dynamically adjust their routes to ensure safe and efficient navigation. Traditional dynamic path planning algorithms struggle to address the extensive variability of Arctic ice conditions. To tackle this issue, this paper improves the D* Lite algorithm by leveraging the gradual and convergent nature of Arctic ice condition changes. The original algorithm’s local update and path extraction rules are modified to prevent chain updates triggered by minor localized changes, thereby reducing the frequency of updates in non-critical areas. By simulating dynamic route planning for ships in Arctic waters during both the freezing and melting periods, the improved D* Lite algorithm was compared with the original D* Lite algorithm and a global update algorithm in terms of voyage distance, risk coefficient, planning time, and the number of node updates. The computational results demonstrate that the improved D* Lite algorithm achieves planning results very similar to those of the original D* Lite algorithm and the global update algorithm at the lowest update cost, significantly enhancing the safety and efficiency of dynamic route planning for ships in Arctic waters.
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Zhang, Fangyuan, and Sibo Wang. "Effective indexing for dynamic structural graph clustering." Proceedings of the VLDB Endowment 15, no. 11 (July 2022): 2908–20. http://dx.doi.org/10.14778/3551793.3551840.
Testo completoAbstract (sommario):
Graph clustering is a fundamental data mining task that clusters vertices into different groups. The structural graph clustering algorithm ( SCAN ) is a widely used graph clustering algorithm that derives not only clustering results, but also special roles of vertices like hubs and outliers. In this paper, we consider structural graph clustering on dynamic graphs under Jaccard similarity. The state-of-the-art index-based solution focuses on static graphs and incurs prohibitive update costs to maintain indices. Lately, an efficient approximate dynamic structural graph clustering algorithm Dyn-StrClu under Jaccard similarity is proposed. However, their solution needs to fix input parameters while parameter settings of SCAN usually need to be fine-tuned to achieve good clustering results. Motivated by these limitations, we present a study on devising effective index structures for SCAN algorithm on dynamic graphs. Similar to the state-of-the-art dynamic scheme, our main idea to reduce the time complexity is still by bringing approximation to clustering results. However, our solution does not need to fix the input parameters. To achieve this, our solution includes two key components. The first is to maintain a bottom- k sketch for each vertex so that the similarities of affected vertices can be easily updated. The second key is a bucketing strategy that allows us to update clustering results and roles of vertices efficiently. Our theoretical analysis shows that our proposed algorithm achieves O (log n · log M + m / pf ) expected update cost and guarantees to return approximate clustering results with probability 1 - pf after up to M updates. Extensive experiments show that our solution is up to two orders of magnitude faster than the state-of-the-art index-based solution while still achieving high-quality clustering results.
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Rumbaugh, Douglas B., and Dong Xie. "Practical Dynamic Extension for Sampling Indexes." Proceedings of the ACM on Management of Data 1, no. 4 (December 8, 2023): 1–26. http://dx.doi.org/10.1145/3626744.
Testo completoAbstract (sommario):
The execution of analytical queries on massive datasets presents challenges due to long response times and high computational costs. As a result, the analysis of representative samples of data has emerged as an attractive alternative; this avoids the cost of processing queries against the entire dataset, while still producing statistically valid results. Unfortunately, the sampling techniques in common use sacrifice either sample quality or performance, and so are poorly suited for this task. However, it is possible to build high quality sample sets efficiently with the assistance of indexes. This introduces a new challenge: real-world data is subject to continuous update, and so the indexes must be kept up to date. This is difficult, because existing sampling indexes present a dichotomy; efficient sampling indexes are difficult to update, while easily updatable indexes have poor sampling performance. This paper seeks to address this gap by proposing a general and practical framework for extending most sampling indexes with efficient update support, based on splitting indexes into smaller shards, combined with a systematic approach to the periodic reconstruction. The framework's design space is examined, with an eye towards exploring trade-offs between update performance, sampling performance, and memory usage. Three existing static sampling indexes are extended using this framework to support updates, and the generalization of the framework to concurrent operations and larger-than-memory data is discussed. Through a comprehensive suite of benchmarks, the extended indexes are shown to match or exceed the update throughput of state-of-the-art dynamic baselines, while presenting significant improvements in sampling latency.
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Li, Haoyang, and Lei Chen. "EARLY: Efficient and Reliable Graph Neural Network for Dynamic Graphs." Proceedings of the ACM on Management of Data 1, no. 2 (June 13, 2023): 1–28. http://dx.doi.org/10.1145/3589308.
Testo completoAbstract (sommario):
Graph neural networks have been widely used to learn node representations for many real-world static graphs. In general, they learn node representations by recursively aggregating information from neighbors. However, graphs in many applications are dynamic, evolving with continuous graph events, such as node feature and graph structure updates. These events require the node representations to be updated accordingly. Currently, due to the real-time requirement, how to efficiently and reliably update node representations under continuous graph events is still an open problem. Recent studies propose two solutions to partially address this problem, but their performance is still limited. First, local-based GNNs only update the nodes directly involved in events, suffering from the quality-deficit issue, since they neglect the other nodes affected by these events. Second, neighbor-sampling GNNs propose to sample neighbors to accelerate neighbor aggregation computations, encountering the neighbor-redundant issue. These sampled neighbors may be similar and cannot reflect the distribution of all neighbors, leading that node representations aggregated on these redundant neighbors may differ from those aggregated on all neighbors. In this paper, we propose an efficient and reliable graph neural network, namely EARLY, to update node representations for dynamic graphs. We first identify the top-k influential nodes that are most affected by graph events. Then, to sample neighbors diversely, we propose a diversity-aware layer-wise sampling technique. We theoretically demonstrate that this technique can decrease the sampling expectation error and learn more reliable node representations. Therefore, the top-k nodes selection and diversity-aware sampling enable EARLY to efficiently update node representations in a reliable way. Extensive experiments on the five real-world graphs demonstrate the effectiveness and efficiency of our proposed EARLY.
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Martinez, Sébastien, Christophe Gransart, Olivier Stienne, Virginie Deniau, and Philippe Bon. "SoREn, How Dynamic Software Update Tools Can Help Cybersecurity Systems to Improve Monitoring and Actions." JUCS - Journal of Universal Computer Science 28, no. (1) (January 28, 2022): 27–53. https://doi.org/10.3897/jucs.66857.
Testo completoAbstract (sommario):
Because stopping a service to apply updates raises issues, Dynamic Software Updating studies the application of updates on programs without disrupting the services they provide. This is acheived using specific mechanisms operating updating tasks such as the modification of the program state. To acheive transparency, Dynamic Software Updating systems use pre-selected and pre-configured mechanisms. Developers provide patches that are transparently converted to dynamic updates. The cost of such transparency is often that applied patches cannot modify the general semantic of the updated program. Allowing dynamic modification of the general semantic of a running program is rarely considered.In the context of protection of communications between moving vehicles and uncontrolled infrastructure, SoREn (Security REconfigurable Engine) is designed to be dynamically reconfigurable. Its semantics can transparently be modified at runtime to change the security policy it enforces. Administrators can supply new policies to trigger a reconfiguration, without developing new components. This paper details and discusses the design of SoREn, its meta-model linked to cybersecurity business concepts and its automatic reconfiguration calculator allowing transparent application of reconfigurations.
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van Benthem, Johan, Jelle Gerbrandy, and Barteld Kooi. "Dynamic Update with Probabilities." Studia Logica 93, no. 1 (September 17, 2009): 67–96. http://dx.doi.org/10.1007/s11225-009-9209-y.
Testo completo
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Han, Jian Ping, and Yong Peng Luo. "Static and Dynamic Finite Element Model Updating of a Rigid Frame-Continuous Girders Bridge Based on Response Surface Method." Advanced Materials Research 639-640 (January 2013): 992–97. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.992.
Testo completoAbstract (sommario):
Using the static and dynamic test data simultaneously to update the finite element model can increase the available information for updating. It can overcome the disadvantages of updating based on static or dynamic test data only. In this paper, the response surface method is adopted to update the finite element model of the structure based on the static and dynamic test. Using the reasonable experiment design and regression techniques, a response surface model is formulated to approximate the relationships between the parameters and response values instead of the initial finite element model for further updating. First, a numerical example of a reinforced concrete simply supported beam is used to demonstrate the feasibility of this approach. Then, this approach is applied to update the finite element model of a prestressed reinforced concrete rigid frame-continuous girders bridge based on in-situ static and dynamic test data. Results show that this approach works well and achieve reasonable physical explanations for the updated parameters. The results from the updated model are in good agreement with the results from the in-situ measurement. The updated finite element model can accurately represent mechanical properties of the bridge and it can serve as a benchmark model for further damage detection and condition assessment of the bridge.
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Han, Min, Sunan Ge, Minghui Wang, Xiaojun Hong, and Jie Han. "A Novel Dynamic Update Framework for Epileptic Seizure Prediction." BioMed Research International 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/957427.
Testo completoAbstract (sommario):
Epileptic seizure prediction is a difficult problem in clinical applications, and it has the potential to significantly improve the patients’ daily lives whose seizures cannot be controlled by either drugs or surgery. However, most current studies of epileptic seizure prediction focus on high sensitivity and low false-positive rate only and lack the flexibility for a variety of epileptic seizures and patients’ physical conditions. Therefore, a novel dynamic update framework for epileptic seizure prediction is proposed in this paper. In this framework, two basic sample pools are constructed and updated dynamically. Furthermore, the prediction model can be updated to be the most appropriate one for the prediction of seizures’ arrival. Mahalanobis distance is introduced in this part to solve the problem of side information, measuring the distance between two data sets. In addition, a multichannel feature extraction method based on Hilbert-Huang transform and extreme learning machine is utilized to extract the features of a patient’s preseizure state against the normal state. At last, a dynamic update epileptic seizure prediction system is built up. Simulations on Freiburg database show that the proposed system has a better performance than the one without update. The research of this paper is significantly helpful for clinical applications, especially for the exploitation of online portable devices.
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Zhang, Fangyuan, Mengxu Jiang, and Sibo Wang. "Efficient Dynamic Weighted Set Sampling and Its Extension." Proceedings of the VLDB Endowment 17, no. 1 (September 2023): 15–27. http://dx.doi.org/10.14778/3617838.3617840.
Testo completoAbstract (sommario):
Given a weighted set S of n elements, weighted set sampling (WSS) samples an element in S so that each element a i ; is sampled with a probability proportional to its weight w ( a i ). The classic alias method pre-processes an index in O ( n ) time with O ( n ) space and handles WSS with O (1) time. Yet, the alias method does not support dynamic updates. By minor modifications of existing dynamic WSS schemes, it is possible to achieve an expected O (1) update time and draw t independent samples in expected O ( t ) time with linear space, which is theoretically optimal. But such a method is impractical and even slower than a binary search tree-based solution. How to support both efficient sampling and updates in practice is still challenging. Motivated by this, we design BUS , an efficient scheme that handles an update in O (1) amortized time and draws t independent samples in O (log n + t) time with linear space. A natural extension of WSS is the weighted independent range sampling (WIRS) , where each element in S is a data point from R. Given an arbitrary range Q = [ℓ, r ] at query time, WIRS aims to do weighted set sampling on the set S Q of data points falling into range Q. We show that by integrating the theoretically optimal dynamic WSS scheme mentioned above, it can handle an update in O (log n ) time and can draw t independent samples for WIRS in O (log n + t ) time, the same as the state-of-the-art static algorithm. Again, such a solution by integrating the optimal dynamic WSS scheme is still impractical to handle WIRS queries. We further propose WIRS-BUS to integrate BUS to handle WIRS queries, which handles each update in O (log n ) time and draws t independent samples in O (log 2 n + t ) time with linear space. Extensive experiments show that our BUS and WIRS-BUS are efficient for both sampling and updates.
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Moti, Moin Hussain, Panagiotis Simatis, and Dimitris Papadias. "Waffle." Proceedings of the VLDB Endowment 16, no. 4 (December 2022): 670–83. http://dx.doi.org/10.14778/3574245.3574253.
Testo completoAbstract (sommario):
Although several spatial indexes achieve fast query processing, they are ineffective for highly dynamic data sets because of costly updates. On the other hand, simple structures that enable efficient updates are slow for spatial queries. In this paper, we propose Waffle , a workload-aware, query-sensitive spatial index, that effectively accommodates both update- and query-intensive workloads. Waffle combines concepts of the space and data partitioning frameworks, and constitutes a complete indexing solution. In addition to query processing algorithms, it includes: (i) a novel bulk loading method that guarantees optimal disk page utilization on static data, (ii) algorithms for dynamic updates that guarantee zero overlapping of nodes, and (iii) a maintenance mechanism that adjusts the tradeoff between query and update speed, based on the workload and query distribution. An extensive experimental evaluation confirms the superiority of Waffle against state of the art space and data partitioning indexes on update and query efficiency.
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Li, Zhaopeng, Deyun Zhong, Zhaohao Wu, Liguan Wang, and Qiwang Tang. "Local Dynamic Updating Method of Orebody Model Based on Mesh Reconstruction and Mesh Deformation." Minerals 11, no. 11 (November 6, 2021): 1232. http://dx.doi.org/10.3390/min11111232.
Testo completoAbstract (sommario):
In this paper, to update the orebody model based on the given interpreted geological information, we present a local dynamic updating method of the orebody model that allows the interactive construction of the constraint deformation conditions and the dynamic updating of the mesh model. The rules for constructing deformation constraints based on the control polylines are discussed. Because only part of the model is updated, the updated mesh is effective and the overall quality is satisfactory. Our main contribution is that we propose a local dynamic updating method for the orebody model based on mesh reconstruction and mesh deformation. This method can automatically update a given 3D orebody model based on a set of unordered geological interpretation lines. Moreover, we implement a deformation neighborhood region search method based on the specified ring radius and a local constrained mesh deformation algorithm for the orebody model. Finally, we test the method and show the model update results with real geological datasets, which proves that this method is effective for the local updating of orebody models.
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Abo Khamis, Mahmoud, Ahmet Kara, Dan Olteanu, and Dan Suciu. "Insert-Only versus Insert-Delete in Dynamic Query Evaluation." Proceedings of the ACM on Management of Data 2, no. 5 (November 4, 2024): 1–26. http://dx.doi.org/10.1145/3695837.
Testo completoAbstract (sommario):
We study the dynamic query evaluation problem: Given a full conjunctive query Q and a sequence of updates to the input database, we construct a data structure that supports constant-delay enumeration of the tuples in the query output after each update. We show that a sequence of N insert-only updates to an initially empty database can be executed in total time O(N w(Q) ), where w(Q) is the fractional hypertree width of Q. This matches the complexity of the static query evaluation problem for Q and a database of size N. One corollary is that the amortized time per single-tuple insert is constant for acyclic full conjunctive queries. In contrast, we show that a sequence of N inserts and deletes can be executed in total time Õ(N w(Q') ), where Q' is obtained from Q by extending every relational atom with extra variables that represent the "lifespans" of tuples in the database. We show that this reduction is optimal in the sense that the static evaluation runtime of Q' provides a lower bound on the total update time for the output of Q. Our approach achieves amortized optimal update times for the hierarchical and Loomis-Whitney join queries.
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Goldstein, Simon. "Generalized Update Semantics." Mind 128, no. 511 (February 8, 2019): 795–835. http://dx.doi.org/10.1093/mind/fzy076.
Testo completoAbstract (sommario):
Abstract This paper explores the relationship between dynamic and truth conditional semantics for epistemic modals. It provides a generalization of a standard dynamic update semantics for modals. This new semantics derives a Kripke semantics for modals and a standard dynamic semantics for modals as special cases. The semantics allows for new characterizations of a variety of principles in modal logic, including the inconsistency of ‘p and might not p’. Finally, the semantics provides a construction procedure for transforming any truth conditional semantics for modals into a dynamic semantics for modals with similar properties.
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Chen, Xin, You Peng, Sibo Wang, and Jeffrey Xu Yu. "DLCR." Proceedings of the VLDB Endowment 15, no. 8 (April 2022): 1645–57. http://dx.doi.org/10.14778/3529337.3529348.
Testo completoAbstract (sommario):
Many real-world graphs, e.g., social networks, biological networks, knowledge graphs, naturally come with edge-labels, with different labels representing different relationships between nodes. On such edge-labeled graphs, an important query is the label-constrained reachability (LCR) query, where we are given a source s , a target t , a label set ψ, and the goal is to check if there exists any path P from s to t such that labels of edges on P all belong to ψ. Existing indexing schemes for LCR queries still focus on static graphs, despite the fact that many edge-labeled graphs are dynamic in nature. Motivated by the limitations of existing solutions, we present a study on how to effectively maintain the indexing scheme on dynamic graphs. Our proposed approach is based on the state-of-the-art 2-hop index for LCR queries. In this paper, we present efficient algorithms for updating the index structure in response to dynamic edge insertions/deletions and demonstrate the correctness of our update algorithms. Following that, we present that adopting a query-friendly but update-unfriendly indexing scheme results in surprisingly superb query/update efficiency and outperforms those update-friendly ones. We analyze and demonstrate that the query-friendly indexing scheme actually achieves the same time complexity as those of update-friendly ones. Finally, we present the batched update algorithms where the updates may include multiple edge insertions/deletions. Extensive experiments show the effectiveness of the proposed update algorithms, query-friendly indexing scheme, and batched update algorithms.
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MAELBRÁNCKE, RUDI, and HENK OLIVIÉ. "DYNAMIC TREE REBALANCING USING RECURRENT ROTATIONS: DYNAMIC TREE REBALANCING." International Journal of Foundations of Computer Science 05, no. 03n04 (December 1994): 247–60. http://dx.doi.org/10.1142/s012905419400013x.
Testo completoAbstract (sommario):
A simple algorithm is given to rebalance a binary search tree of optimal height after a single update. The algorithm uses time which is linear in the number of nodes. In comparison to previous algorithms it is short and very easy to implement. Moreover, this algorithm can be used to implement other classes of balanced trees and it is suitable for each update. When applied to perfectly balanced trees it has a lower average cost than previous algorithms.
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Eldin, Neil N., and Ahmed B. Senouci. "Scheduling and control of linear projects." Canadian Journal of Civil Engineering 21, no. 2 (April 1, 1994): 219–30. http://dx.doi.org/10.1139/l94-025.
Testo completoAbstract (sommario):
A two-state-variable, N-stage dynamic programming approach to scheduling and control of linear projects is presented. This approach accounts for practical considerations related to work continuity, interruptions, and lags between successive activities. In the dynamic programming formulation, stages represent project activities and state variables represent possible activity resources and interruptions at each location. The objective of the dynamic programming solution is to provide for the selection of resources, interruptions, and lags for production activities that lead to the minimum project total cost. In addition, the presented system produces a graphical presentation of the optimum project schedule and updates the original schedule based on update information input by the user. The updated schedule determines the new completion date, and forecasts the project new total cost based on the current project performance. A small linear project is provided as a numerical illustration of the system. Key words: dynamic programming, linear projects, scheduling systems, optimization of cost and scheduling durations.
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Anadiotis, Angelos Christos, Muhammad Ghufran Khan, and Ioana Manolescu. "Dynamic Graph Databases with Out-of-Order Updates." Proceedings of the VLDB Endowment 17, no. 13 (September 2024): 4799–812. https://doi.org/10.14778/3704965.3704984.
Testo completoAbstract (sommario):
Several real-time applications rely on dynamic graphs to model and store data arriving from multiple streams. Providing both high ingestion rate and efficient analytics with transactional guarantees is challenging, even more so when updates may be received out-of-order at the database. In this work, we propose HAL, a novel in-memory dynamic graph database design, addressing these challenges. HAL outperforms comparable systems by a factor of up to 73× in terms of update processing throughput and up to 357× for analytics, while being the first to support out-of-order updates.
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Yadav, Pratyaksh, Pramoda Kumara K M, Burhan Pasha, and Dr Mohana S D. "Remote ESP32 Holographic Display System." INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 09, no. 03 (March 29, 2025): 1–9. https://doi.org/10.55041/ijsrem43269.
Testo completoAbstract (sommario):
This paper presents the design and implementation of a remote-update holographic display system utilizing the ESP32 microcontroller. The system facilitates dynamic image projection through a combination of hardware and software components. A web server acts as an intermediary for image storage and distribution, while a mobile application offers a user-friendly interface for image selection and system control. The ESP32, upon network connection and IP address acquisition, communicates with the web server to retrieve updated image data, enabling real-time content modification. This configuration allows for versatile and interactive holographic presentations. Key Words: ESP32, holographic display, remote update, web server, mobile application, IP address, dynamic projection
27
Jung, Yoo Sun, Flávio D. S. Souza, Andrew Q. Philips, Amanda Rutherford, and Guy D. Whitten. "A command to estimate and interpret models of dynamic compositional dependent variables: New features for dynsimpie." Stata Journal: Promoting communications on statistics and Stata 20, no. 3 (September 2020): 584–603. http://dx.doi.org/10.1177/1536867x20953570.
Testo completoAbstract (sommario):
Philips, Rutherford, and Whitten (2016, Stata Journal 16: 662–677) introduced dynsimpie, a command to examine dynamic compositional dependent variables. In this article, we present an update to dynsimpie and three new adofiles: cfbplot, effectsplot, and dynsimpiecoef. These updates greatly enhance the range of models that can be estimated and the ways in which model results can now be presented. The command dynsimpie has been updated so that users can obtain both prediction plots and change-from-baseline plots using postestimation commands. With the new command dynsimpiecoef, various types of coefficient plots can also be obtained. We illustrate these improvements using monthly data on support for political parties in the United Kingdom.
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SLOTA, MARTIN, JOÃO LEITE, and TERRANCE SWIFT. "Splitting and updating hybrid knowledge bases." Theory and Practice of Logic Programming 11, no. 4-5 (July 2011): 801–19. http://dx.doi.org/10.1017/s1471068411000317.
Testo completoAbstract (sommario):
AbstractOver the years, nonmonotonic rules have proven to be a very expressive and useful knowledge representation paradigm. They have recently been used to complement the expressive power of Description Logics (DLs), leading to the study of integrative formal frameworks, generally referred to ashybrid knowledge bases, where both DL axioms and rules can be used to represent knowledge. The need to use these hybrid knowledge bases in dynamic domains has called for the development of update operators, which, given the substantially different way DLs and rules are usually updated, has turned out to be an extremely difficult task. In Slota and Leite (2010b Towards Closed World Reasoning in Dynamic Open Worlds.Theory and Practice of Logic Programming, 26th Int'l. Conference on Logic Programming (ICLP'10) Special Issue10(4–6) (July), 547–564.), a first step towards addressing this problem was taken, and an update operator for hybrid knowledge bases was proposed. Despite its significance—not only for being the first update operator for hybrid knowledge bases in the literature, but also because it has some applications—this operator was defined for a restricted class of problems where only the ABox was allowed to change, which considerably diminished its applicability. Many applications that use hybrid knowledge bases in dynamic scenarios require both DL axioms and rules to be updated. In this paper, motivated by real world applications, we introduce an update operator for a large class of hybrid knowledge bases where both the DL component as well as the rule component are allowed to dynamically change. We introduce splitting sequences and splitting theorem for hybrid knowledge bases, use them to define a modular update semantics, investigate its basic properties, and illustrate its use on a realistic example about cargo imports.
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Narayanareddy, Mugireddy Satya, Lekireddy Rajasekharreddy, Isani Swetha, and P. V. Jagadeeswara Prasad. "SYMMETRIC-KEY BASED VERIFICATION OF KEYWORD SEARCH OVER DYNAMIC ENCRYPTED CLOUD DATA." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 11, no. 3 (December 15, 2020): 2736–41. http://dx.doi.org/10.61841/turcomat.v11i3.14517.
Testo completoAbstract (sommario):
Searchable and Verifiable As a crucial method of cloud security, symmetric encryption enables users to search for encrypted data in the cloud using keywords and validate the accuracy of the results. One of the most prevalent and important requirements for data owners in such schemes is dynamic update for cloud data. To our knowledge, all of the verifiable SSE systems that permit data dynamic update currently in use are based on asymmetric-key cryptography verification, which necessitates time-consuming processes. The sheer volume of cloud data could make the overhead of verification a major burden. Consequently, a crucial unsolved topic is how to implement keyword search over dynamic encrypted cloud data with effective verification. In this research, we investigate how to accomplish keyword search over dynamically encrypted cloud data with symmetric-key based verification and suggest a workable technique. In order to support the efficient verification of dynamic data, we design a novel Accumulative Authentication Tag (AAT) based on the symmetric-key cryptography to generate an authentication tag for each keyword. Benefiting from the accumulation property of our designed AAT, the authentication tag can be conveniently updated when dynamic operations on cloud data occur. In order to achieve efficient data update, we design a new secure index composed by a search table ST based on the orthogonal list and a verification list VL containing AATs. Owing to the connectivity and the flexibility of ST, the update efficiency can be significantly improved. The security analysis and the performance evaluation results show that the proposed scheme is secure and efficient.
30
Shenigaram, Vidhya, Ladhwe Shri Megha, Rajasekharaiah Matada Kattigehally, and Swarnaja Mettu. "SYMMETRIC-KEY BASED VERIFICATION OF KEYWORD SEARCH OVER DYNAMIC ENCRYPTED CLOUD DATA." Turkish Journal of Computer and Mathematics Education (TURCOMAT) 11, no. 3 (December 15, 2020): 2696–702. http://dx.doi.org/10.61841/turcomat.v11i3.14483.
Testo completoAbstract (sommario):
Searchable and Verifiable As a crucial method of cloud security, symmetric encryption enables users to search for encrypted data in the cloud using keywords and validate the accuracy of the results. One of the most prevalent and important requirements for data owners in such schemes is dynamic update for cloud data. To our knowledge, all of the verifiable SSE systems that permit data dynamic update currently in use are based on asymmetric-key cryptography verification, which necessitates time-consuming processes. The sheer volume of cloud data could make the overhead of verification a major burden. Consequently, a crucial unsolved topic is how to implement keyword search over dynamic encrypted cloud data with effective verification. In this research, we investigate how to accomplish keyword search over dynamically encrypted cloud data with symmetric-key based verification and suggest a workable technique. In order to support the efficient verification of dynamic data, we design a novel Accumulative Authentication Tag (AAT) based on the symmetric-key cryptography to generate an authentication tag for each keyword. Benefiting from the accumulation property of our designed AAT, the authentication tag can be conveniently updated when dynamic operations on cloud data occur. In order to achieve efficient data update, we design a new secure index composed by a search table ST based on the orthogonal list and a verification list VL containing AATs. Owing to the connectivity and the flexibility of ST, the update efficiency can be significantly improved. The security analysis and the performance evaluation results show that the proposed scheme is secure and efficient.
31
MASUD, MD MEHEDI, ILUJU KIRINGA, and HASAN URAL. "UPDATE PROCESSING IN INSTANCE-MAPPED P2P DATA SHARING SYSTEMS." International Journal of Cooperative Information Systems 18, no. 03n04 (September 2009): 339–79. http://dx.doi.org/10.1142/s021884300900204x.
Testo completoAbstract (sommario):
We consider the problem of update processing in a peer-to-peer (P2P) database network where each peer consists of an independently created relational database. We assume that peers store related data, but data has heterogeneity wrt instances and schemas. The differences in schema and data vocabulary are bridged by value correspondences called mapping tables. Peers build an overlay network called acquaintance network, in which each peer may get acquainted with any other peer that stores related data. In this setting, the updates are free to initiate in any peer and are executed over other peers which are acquainted directly or indirectly with the updates initiator. The execution of an update is achieved by translating, through mapping tables, the update into a set of updates that are executed against the acquainted peers. We consider both the soundness and completeness of update translation. When updates are generated and propagated in the network initiated from a peer, a tree is built dynamically called Update Dependency Tree (UDT). The UDT depicts the relationships among the component updates generated from the initial update. We also discuss the issues of the update propagation when a peer is temporarily unavailable or offline. Our propagation mechanism keeps track of a peer when the peer is not available for a certain period of time and once the peer comes back online the system propagates the updates destined to the returning peer to keep it's database synchronized. Moreover, conflict detection and resolution strategies have been proposed for such a dynamic P2P database network. We have implemented and experimentally tested a prototype of our update processing mechanism on a small P2P database network. We show the results of our experiments.
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Ghemawat, Pankaj. "Evolving Ideas about Business Strategy." Business History Review 90, no. 4 (2016): 727–49. http://dx.doi.org/10.1017/s0007680516000702.
Testo completoAbstract (sommario):
This paper updates an earlier article published in Business History Review that concluded that by the second half of the 1990s, there had been a profusion of new, purportedly practical ideas about strategy, many of which embodied some explicit dynamics. This update provides several indications of a drop-off since then in the rate of development of new ideas about strategy but also a continued focus, in the new ideas that are being developed, on dynamics. And since our stock of dynamic frameworks has, based on one enumeration, more than doubled in the last fifteen to twenty years, updating expands both the need and the empirical basis for some generalizations about the types of dynamic strategy frameworks—and strategy frameworks in general—that managers are likely to find helpful versus those that they are not.
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Müller, Peter Marvin, Georgios Bletsos, and Thomas Rung. "Shape Transformation Approaches for Fluid Dynamic Optimization." Aerospace 10, no. 6 (May 31, 2023): 519. http://dx.doi.org/10.3390/aerospace10060519.
Testo completoAbstract (sommario):
The contribution is devoted to combined shape- and mesh-update strategies for parameter-free (CAD-free) shape optimization methods. Three different strategies to translate the shape sensitivities computed by adjoint shape optimization procedures into simultaneous updates of both the shape and the discretized domain are employed in combination with a mesh-morphing strategy. Considered methods involve a linear Steklov–Poincaré (Hilbert space) approach, a recently suggested highly non-linear p-Laplace (Banach space) method, and a hybrid variant which updates the shape in Hilbert space. The methods are scrutinized for optimizing the power loss of a two-dimensional bent duct flow using an unstructured, locally refined grid that initially displays favorable grid properties. Optimization results are compared with respect to the optimization convergence, the computational effort, and the preservation of the mesh quality during the optimization sequence. Results indicate that all methods reach, approximately, the same converged optimal solution, which reduces the objective function by about 18% for this classical benchmark example. However, as regards the preservation of the mesh quality, more advanced Banach space methods are advantageous in comparison to Hilbert space methods even when the shape update is performed in Hilbert space to save costs. In specific, while the computational cost of the Banach space method and the hybrid method is about 3.5 and 2.5 times the cost of the pure Hilbert space method, respectively, the grid quality metrics are 2 times and 1.7 times improved for the Banach space and hybrid method, respectively.
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Bhore, Sujoy, Guangping Li, and Martin Nöllenburg. "An Algorithmic Study of Fully Dynamic Independent Sets for Map Labeling." ACM Journal of Experimental Algorithmics 27 (December 31, 2022): 1–36. http://dx.doi.org/10.1145/3514240.
Testo completoAbstract (sommario):
Map labeling is a classical problem in cartography and geographic information systems that asks to place labels for area, line, and point features, with the goal to select and place the maximum number of independent (i.e., overlap-free) labels. A practically interesting case is point labeling with axis-parallel rectangular labels of common size. In a fully dynamic setting, at each timestep, either a new label appears or an existing label disappears. Then, the challenge is to maintain a maximum cardinality subset of pairwise independent labels with sublinear update time. Motivated by this, we study the maximal independent set ( MIS ) and maximum independent set ( Max-IS ) problems on fully dynamic (insertion/deletion model) sets of axis-parallel rectangles of two types: (i) uniform height and width and (ii) uniform height and arbitrary width; both settings can be modeled as rectangle intersection graphs. We present the first deterministic algorithm for maintaining an MIS (and thus a 4-approximate Max-IS ) of a dynamic set of uniform rectangles with polylogarithmic update time. This breaks the natural barrier of \( \Omega (\Delta) \) update time (where \( \Delta \) is the maximum degree in the graph) for vertex updates presented by Assadi et al. (STOC 2018). We continue by investigating Max-IS and provide a series of deterministic dynamic approximation schemes. For uniform rectangles, we first give an algorithm that maintains a 4-approximate Max-IS with \( O(1) \) update time. In a subsequent algorithm, we establish the trade-off between approximation quality \( 2(1+\frac{1}{k}) \) and update time \( O(k^2\log n) \) , for \( k\in \mathbb {N} \) . We conclude with an algorithm that maintains a 2-approximate Max-IS for dynamic sets of unit-height and arbitrary-width rectangles with \( O(\log ^2 n + \omega \log n) \) update time, where \( \omega \) is the maximum size of an independent set of rectangles stabbed by any horizontal line. We implement our algorithms and report the results of an experimental comparison exploring the trade-off between solution quality and update time for synthetic and real-world map labeling instances. We made several major observations in our empirical study. First, the original approximations are well above their respective worst-case ratios. Second, in comparison with the static approaches, the dynamic approaches show a significant speedup in practice. Third, the approximation algorithms show their predicted relative behavior. The better the solution quality, the worse the update times. Fourth, a simple greedy augmentation to the approximate solutions of the algorithms boost the solution sizes significantly in practice.
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Krishna, Shankaranarayanan, Aniket Lal, Andreas Pavlogiannis, and Omkar Tuppe. "On-the-Fly Static Analysis via Dynamic Bidirected Dyck Reachability." Proceedings of the ACM on Programming Languages 8, POPL (January 5, 2024): 1239–68. http://dx.doi.org/10.1145/3632884.
Testo completoAbstract (sommario):
Dyck reachability is a principled, graph-based formulation of a plethora of static analyses. Bidirected graphs are used for capturing dataflow through mutable heap data, and are usual formalisms of demand-driven points-to and alias analyses. The best (offline) algorithm runs in O ( m + n · α( n )) time, where n is the number of nodes and m is the number of edges in the flow graph, which becomes O ( n 2 ) in the worst case. In the everyday practice of program analysis, the analyzed code is subject to continuous change, with source code being added and removed. On-the-fly static analysis under such continuous updates gives rise to dynamic Dyck reachability, where reachability queries run on a dynamically changing graph, following program updates. Naturally, executing the offline algorithm in this online setting is inadequate, as the time required to process a single update is prohibitively large. In this work we develop a novel dynamic algorithm for bidirected Dyck reachability that has O ( n · α( n )) worst-case performance per update, thus beating the O ( n 2 ) bound, and is also optimal in certain settings. We also implement our algorithm and evaluate its performance on on-the-fly data-dependence and alias analyses, and compare it with two best known alternatives, namely (i) the optimal offline algorithm, and (ii) a fully dynamic Datalog solver. Our experiments show that our dynamic algorithm is consistently, and by far, the top performing algorithm, exhibiting speedups in the order of 1000X. The running time of each update is almost always unnoticeable to the human eye, making it ideal for the on-the-fly analysis setting.
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Kobayashi, Mikito, and Satoshi Tojo. "Agent Communication for Dynamic Belief Update." Transactions of the Japanese Society for Artificial Intelligence 24 (2009): 314–21. http://dx.doi.org/10.1527/tjsai.24.314.
Testo completo
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Caramella, C., P. Colombo, U. Conte, and A. La Manna. "Tablet Disintegration Update: The Dynamic Approach." Drug Development and Industrial Pharmacy 13, no. 12 (January 1987): 2111–45. http://dx.doi.org/10.3109/03639048709020576.
Testo completo
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Nahabedian, Leandro, Victor Braberman, Nicolas Dippolito, Shinichi Honiden, Jeff Kramer, Kenji Tei, and Sebastian Uchitel. "Dynamic Update of Discrete Event Controllers." IEEE Transactions on Software Engineering 46, no. 11 (November 1, 2020): 1220–40. http://dx.doi.org/10.1109/tse.2018.2876843.
Testo completo
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Aucher, Guillaume. "Dynamic epistemic logic in update logic." Journal of Logic and Computation 26, no. 6 (March 7, 2016): 1913–60. http://dx.doi.org/10.1093/logcom/exw002.
Testo completo
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D'Angelo, Gianlorenzo, Mattia D'Emidio, and Daniele Frigioni. "Fully dynamic update of arc-flags." Networks 63, no. 3 (January 27, 2014): 243–59. http://dx.doi.org/10.1002/net.21542.
Testo completo
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Qiangqiang, Sun, Qiu Huijun, and Cai Meng. "Transmitting Systems Dynamics in SCADA using Uneven Sampling/ Cubic Spline Interpolation based Data Compression." Open Electrical & Electronic Engineering Journal 8, no. 1 (December 31, 2014): 544–51. http://dx.doi.org/10.2174/1874129001408010544.
Testo completoAbstract (sommario):
Grasping power system dynamic information is helpful for dispatcher in the control center to take correct control action in time under emergency condition. Traditionally, Supervisory Control and Data Acquisition (SCADA) cannot transmit power system dynamics information since it updates system information once every several seconds. Based on the development of substation automation system, a data compression based approach is proposed in this paper to transmit power system dynamics information in existing SCADA. An uneven sampling is utilized to extract the feature points that determine the profile of system dynamics. Thereafter, these feature points contain dynamic information is transmitted from Remote Terminal Units to the control center. The system dynamics can thus be reconstructed with cubic spline interpolation. Numerical simulation on a 36 nodes system suggests that the system dynamics could be transmitted with high fidelity in existing SCADA using the proposed approach. Moreover, the proposed approach can be implemented in SCADA with limited software update.
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Li, Yuan Zheng. "Mean-Shift Guided Particle Filter Tracking Method Based on Layered Dynamic Template Update." Advanced Materials Research 846-847 (November 2013): 1217–20. http://dx.doi.org/10.4028/www.scientific.net/amr.846-847.1217.
Testo completoAbstract (sommario):
Traditional tracking algorithm is not compatible between robustness and efficiency, under complex scenes, the stable template update strategy is not robust to target appearance changes. Therefore, the paper presents a dynamic template-update method that combined with a mean-shift guided particle filter tracking method. By incorporating the original information into the updated template, or according to the variety of each component in template to adjust the updating weights adaptively, the presented algorithm has the natural ability of anti-drift. Besides, the proposed method cope the one-step iteration of mean-shift algorithm with the particle filter, thus boost the performance of efficiency. Experimental results show the feasibility of the proposed algorithm in this paper.
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Wang, Guizhi. "THE DESIGN AND PRODUCT OF NATIONAL 1:1000000 CARTOGRAPHIC DATA OF TOPOGRAPHIC MAP." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 7, 2016): 245–49. http://dx.doi.org/10.5194/isprs-archives-xli-b2-245-2016.
Testo completoAbstract (sommario):
National administration of surveying, mapping and geoinformation started to launch the project of national fundamental geographic information database dynamic update in 2012. Among them, the 1:50000 database was updated once a year, furthermore the 1:250000 database was downsized and linkage-updated on the basis. In 2014, using the latest achievements of 1:250000 database, comprehensively update the 1:1000000 digital line graph database. At the same time, generate cartographic data of topographic map and digital elevation model data. This article mainly introduce national 1:1000000 cartographic data of topographic map, include feature content, database structure, Database-driven Mapping technology, workflow and so on.
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Wang, Guizhi. "THE DESIGN AND PRODUCT OF NATIONAL 1:1000000 CARTOGRAPHIC DATA OF TOPOGRAPHIC MAP." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 7, 2016): 245–49. http://dx.doi.org/10.5194/isprsarchives-xli-b2-245-2016.
Testo completoAbstract (sommario):
National administration of surveying, mapping and geoinformation started to launch the project of national fundamental geographic information database dynamic update in 2012. Among them, the 1:50000 database was updated once a year, furthermore the 1:250000 database was downsized and linkage-updated on the basis. In 2014, using the latest achievements of 1:250000 database, comprehensively update the 1:1000000 digital line graph database. At the same time, generate cartographic data of topographic map and digital elevation model data. This article mainly introduce national 1:1000000 cartographic data of topographic map, include feature content, database structure, Database-driven Mapping technology, workflow and so on.
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Mayer, Andreas, Vijay Balasubramanian, Aleksandra M. Walczak, and Thierry Mora. "How a well-adapting immune system remembers." Proceedings of the National Academy of Sciences 116, no. 18 (April 15, 2019): 8815–23. http://dx.doi.org/10.1073/pnas.1812810116.
Testo completoAbstract (sommario):
An adaptive agent predicting the future state of an environment must weigh trust in new observations against prior experiences. In this light, we propose a view of the adaptive immune system as a dynamic Bayesian machinery that updates its memory repertoire by balancing evidence from new pathogen encounters against past experience of infection to predict and prepare for future threats. This framework links the observed initial rapid increase of the memory pool early in life followed by a midlife plateau to the ease of learning salient features of sparse environments. We also derive a modulated memory pool update rule in agreement with current vaccine-response experiments. Our results suggest that pathogenic environments are sparse and that memory repertoires significantly decrease infection costs, even with moderate sampling. The predicted optimal update scheme maps onto commonly considered competitive dynamics for antigen receptors.
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Sanchez-Gomez, Jesús Manuel, Miguel Ángel Vega-Rodríguez, and Sánchez Carlos Javier Pérez. "Automatic update summarization by a multi-objective number-one-selection genetic approach." IEEE Transactions on Cybernetics 53, no. 12 (June 7, 2023): 7443–54. https://doi.org/10.1109/TCYB.2022.3223163.
Testo completoAbstract (sommario):
Currently, the explosive growth of the information available on the internet makes automatic text summarization systems increasingly important. A particularly relevant challenge is the update summarization task. Update summarization differs from traditional summarization in its dynamic nature. While traditional summarization is static, i.e., the document collections about a specific topic remain unchanged, update summarization addresses dynamic document collections based on a specific topic. Therefore, update summarization consists of summarizing the new document collection under the assumption that the user has already read a previous summarization and only the new information is interesting. The Multi-Objective Number-One selection Genetic Algorithm (MONOGA) has been designed and implemented to address this problem. The proposed algorithm produces a summary that is relevant to the user’s given query, and it also contains updates information. Experiments were conducted on Text Analysis Conference (TAC) datasets, and Recall-Oriented Understudy for Gisting Evaluation (ROUGE) metrics were considered to assess the model performance. The results obtained by the proposed approach outperform those from the existing approaches in the scientific literature, obtaining average percentage improvements between 12.74% and 55.03% in the ROUGE scores.
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Weerasuriya, Chathika Krishan, Rebecca Claire Harris, Christopher Finn McQuaid, Gabriela B. Gomez, and Richard G. White. "Updating age-specific contact structures to match evolving demography in a dynamic mathematical model of tuberculosis vaccination." PLOS Computational Biology 18, no. 4 (April 22, 2022): e1010002. http://dx.doi.org/10.1371/journal.pcbi.1010002.
Testo completoAbstract (sommario):
We investigated the effects of updating age-specific social contact matrices to match evolving demography on vaccine impact estimates. We used a dynamic transmission model of tuberculosis in India as a case study. We modelled four incremental methods to update contact matrices over time, where each method incorporated its predecessor: fixed contact matrix (M0), preserved contact reciprocity (M1), preserved contact assortativity (M2), and preserved average contacts per individual (M3). We updated the contact matrices of a deterministic compartmental model of tuberculosis transmission, calibrated to epidemiologic data between 2000 and 2019 derived from India. We additionally calibrated the M0, M2, and M3 models to the 2050 TB incidence rate projected by the calibrated M1 model. We stratified age into three groups, children (<15y), adults (≥15y, <65y), and the elderly (≥65y), using World Population Prospects demographic data, between which we applied POLYMOD-derived social contact matrices. We simulated an M72-AS01E-like tuberculosis vaccine delivered from 2027 and estimated the per cent TB incidence rate reduction (IRR) in 2050 under each update method. We found that vaccine impact estimates in all age groups remained relatively stable between the M0–M3 models, irrespective of vaccine-targeting by age group. The maximum difference in impact, observed following adult-targeted vaccination, was 7% in the elderly, in whom we observed IRRs of 19% (uncertainty range 13–32), 20% (UR 13–31), 22% (UR 14–37), and 26% (UR 18–38) following M0, M1, M2 and M3 updates, respectively. We found that model-based TB vaccine impact estimates were relatively insensitive to demography-matched contact matrix updates in an India-like demographic and epidemiologic scenario. Current model-based TB vaccine impact estimates may be reasonably robust to the lack of contact matrix updates, but further research is needed to confirm and generalise this finding.
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Li, Xingcheng, and Shuangbiao Zhang. "A Real-Time Structure of Attitude Algorithm for High Dynamic Bodies." Journal of Control Science and Engineering 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9542423.
Testo completoAbstract (sommario):
To solve the real-time problem of attitude algorithm for high dynamic bodies, a real-time structure of attitude algorithm is developed by analyzing the conventional structure that has two stages, and a flow diagram of a real-time structure for a Matlab program is provided in detail. During the update of the attitude matrix, the real-time structure saves every element of attitude matrix in minor loop in real time and updates the next attitude matrix based on the previous matrix every subsample time. Thus, the real-time structure avoids lowering updating frequency, though the multisubsample algorithms are used. Simulation and analysis show that the real-time structure of attitude algorithm is better than the conventional structure due to short update time of attitude matrix and small drifting error, and it is more appropriate for high dynamic bodies.
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Yang, Xianhao, Xiongfeng Deng, Liang Tao, and Binzi Xu. "Neuroadaptive Dynamic Surface Asymptotic Tracking Control of a VTOL Aircraft with Unknown Dynamics and External Disturbances." Mathematics 11, no. 12 (June 15, 2023): 2725. http://dx.doi.org/10.3390/math11122725.
Testo completoAbstract (sommario):
This work studies the asymptotic tracking control problem of a vertical take-off and landing (VTOL) aircraft with unknown dynamics and external disturbances. The unknown nonlinear dynamics of the VTOL aircraft are approximated via the introduction of radial basis function neural networks. Then, the weight update laws are designed. Furthermore, the parameter update control laws are presented to deal with the errors generated during the approximation process and the external disturbances of the aircraft system. Moreover, first-order filters are introduced to avoid repeated differentiation of the designed virtual control laws, thereby effectively eliminating the “complexity explosion” problem caused by traditional backstepping control. Based on the application of the neural network control method, dynamic surface control technique, weight update laws and parameter update control laws, neuroadaptive dynamic surface control laws for the aircraft system are finally proposed. Theoretical analysis shows that the proposed control law can ensure that the aircraft system asymptotically tracks the reference trajectories and the tracking errors can converge to a small neighborhood of zero by choosing the appropriate designed parameters. Finally, simulation examples are provided to verify the effectiveness of proposed control laws.
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Buza, Antal. "Extension of CQL over Dynamic Databases." JUCS - Journal of Universal Computer Science 12, no. (9) (September 28, 2006): 1165–76. https://doi.org/10.3217/jucs-012-09-1165.
Testo completoAbstract (sommario):
CQL, Continuous Query Language is suitable for data stream queries. Sometimes it is better if the queries operate on relational databases and data streams simultaneously. The execution of a CQL query takes a long time (several hours, days or even more). It is not clear what kind of semantics is suitable for the user when the database is updated during the execution of a CQL query. In this paper we give a short description of CQL, a characterization of update-problems, and we offer possible suggestions for the semantic extension of CQL. After the expansion, the CQL would be suitable for solving much more practical problems. The parallel usage of continuous data streams and updatable databases would be settled.