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Applications of Graph Theory
Published in Rowan Garnier, John Taylor, Discrete Mathematics, 2020
In the prefix (or Polish) form of an expression, the symbol for the binary operation is written before the two elements or expressions which it combines. Thus aZYis the prefix form of the expression XαY. Parentheses are not necessary when using prefix notation as there is no inherent ambiguity. For example, the expressions (x ⊕ y)* z and x ⊕ (y * z) have the respective prefix forms *⊕xyz and ⊕x*yz. Write each of the expressions in question 10 (i) above in prefix notation.Describe how the binary tree of an expression can be obtained from its prefix form.
RFID Data Warehousing and Analysis
Published in Lu Yan, Yan Zhang, Laurence T. Yang, Huansheng Ning, The Internet of Things, 2008
An alternative compression mechanism is to store a single transition record for the 50 CDs that move together from the warehouse to the shelf, i.e., to group transitions and not stays. The problem with transition compression is that it makes it difficult to answer queries about items at a given location or going through a series of locations. For example, in order to answer the query: What is the average time that CDs stay at the shelf? you can directly get the information from the stay records with location = shelf, but if only transition records are available, you need to find all the transition records with origin = shelf and the ones with destination = shelf join them on the EPC and compute departure time–arrival time. Another method of compression would be to look at the sequence of locations that an item goes through as a string, and use a Trie [6] to store the strings. The Trie data structure is a tree where each node is associated with a string prefix, and all descendant of the node share the prefix. The problem with this approach is that you lose compression power. In the CDs example, if the 50 items all stay at the warehouse together, but they come from different locations, a trie would have to create distinct nodes for each, thus gaining no compression.
Multibit Tries
Published in Weidong Wu, Packet Forwarding Technologies, 2007
Before 1993, Internet addressing architecture partitioned the IP address space into five classes—A, B, C, D, and E. Typically, the forwarding table had three parts: A, B, C. All prefixes in the same part had fixed length: 8, 16, and 24. The fact that restricted prefix lengths lead to faster search is well known. After the deployment of Classes Inter-Domain Routing in 1993, prefixes could be of arbitrary length from 8 to 32 rather than being constrained to 8, 16, or 24 bits. The idea of the controlled prefix expansion (CPE) was to reduce a set of arbitrary length prefixes to a set of the predefined length prefixes [6].
Intelligent information flow management system in innovative scientific and industrial clusters
Published in International Journal of Parallel, Emergent and Distributed Systems, 2022
Artur Zaenchkovski, Alexey Lazarev, Dmitrii Tukaev, Victor Epifanov
Taking into account the fact that standardised representation of the DHCP server is implemented by randomised distribution of an addresses pool in automatic mode, or by temporary lease for dynamic distribution, it is proposed to focus on using a manual method of providing an IP address to the client in the system being developed. The solution to the problem of two-way authentication within IPv6 addressing is a sequence generation algorithm based on a trained neural network model. The main parameters for synchronising a two-way connection are the following: Network prefix. It is a static expression inherent in one client per dedicated server.Start/end EUI-64 address, represented as a 128-bit sequence. It is also the initial entry point of the neural network model dataset.
NMR-TS: de novo molecule identification from NMR spectra
Published in Science and Technology of Advanced Materials, 2020
Jinzhe Zhang, Kei Terayama, Masato Sumita, Kazuki Yoshizoe, Kengo Ito, Jun Kikuchi, Koji Tsuda
As mentioned above, ChemTS is a tool that combines a RNN with MCTS. In the context of ChemTS, the MCTS is essentially executed on a prefix search tree. One advantage of 1 H NMR spectrum identification is that an enormous number of molecular spectra have been recorded and stored in databases. An intuitive way of utilizing such information is to preload the MCTS prefix search tree with the SMILES strings of the molecules in the database and update the scoring of each traversed node with the WS between the database spectrum and the target spectrum. In computer science, such a prefix tree is usually called trie [42]. See Fig. S2 for an example of trie. We implemented this idea by constructing a trie tree as follows. At every iteration, we inserted one database SMILES string into the trie, on which the nodes were defined in the same way as in ChemTS. After each insertion, the WS of the added SMILES string was used to update the weight of each visited node. The number of preloaded molecules is called the trie size. In our experiments, we tested trie sizes of 0, 1, 100, 1000, and 9800. When the trie size was 1, 100, 1000, and 9800, we ranked the WS for each molecule in the database and selected the top 1, 100, 1000 and 9800 candidates, respectively. The algorithm for trie enhancement is shown in Figure S1.
Efficient name matching based on a fast two-dimensional filter in named data networking
Published in International Journal of Parallel, Emergent and Distributed Systems, 2019
Primarily, the Internet was intended to allow resource sharing among end-hosts. Since its starting, the Internet has developed swiftly, and the services supplied by the Internet have grown explosively. Many common Internet applications have been noticed: simple resource sharing is joined by HTML web-pages, Email, content delivery, video streaming, and voice over IP. Nowadays, the big interesting of Internet users is about retrieving information from the network and the Internet has efficiently became an information spreading platform [21]. Also, the Internet infrastructure has developed towards an information-centric network with a layered pattern. The design of IP layer, that allows to network connectivity, ensures conversations between end-hosts. In order to forward an IP packet, the destination IP address is used as a key to accomplish a longest prefix match within the forwarding information base of the network entity. Nowadays, the most widespread employed manner is by requesting Universal Resource Locater (URL) [22]. URLs cannot be managed in the IP layer directly, but instead depend on redirections of the Domain Name System (DNS), which maps domain URL names into IP addresses. Fundamentally, the existing Internet depends deeply on middle-boxes and layers of redirections, making the network difficult to configure and less efficient [23].