Segui questo link per vedere altri tipi di pubblicazioni sul tema: Fixed length code.
Articoli di riviste sul tema "Fixed length code"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Fixed length code".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Irshid, Mansour I. "A Simple Binary Run-Length Compression Technique for Non-Binary Sources Based on Source Mapping". Active and Passive Electronic Components 24, n. 4 (2001): 211–21. http://dx.doi.org/10.1155/2001/23505.
Testo completoAbstract (sommario):
In this paper, we propose a very simple and efficient binary run-length compression technique for non-binary sources. The technique is based on mapping the non-binary information source into an equivalent binary source using a new fixed-length code instead of the ASCII code. The codes are chosen such that the probability of one of the two binary symbols; say zero, at the output of the mapper is made as small as possible. Moreover, the “all ones” code is excluded from the code assignments table to ensure the presence of at least one “zero” in each of the output codewords. Compression is achieved by encoding the number of “ones” between two consecutive “zeros” using either a fixed-length code or a variable-length code. When applying this simple encoding technique to English text files, we achieve a compression of 5.44bits/character and 4.6bits/character for the fixed-length code and the variablelength (Huffman) code, respectively.
2
Farkaš, Peter, e Frank Schindler. "Run length limited error control codes construction based on one control matrix property". Journal of Electrical Engineering 68, n. 4 (28 agosto 2017): 322–24. http://dx.doi.org/10.1515/jee-2017-0046.
Testo completoAbstract (sommario):
AbstractIn this manuscript a simple method is presented for constructing run length limited error control codes from linear binary block codes. The run length limited properties are obtained via addition of a carefully chosen fixed binary vector - a modifier to all codewords without introducing any additional redundancy. Modifier selection is based on a specific property, which can be found in some of the linear binary block codes control matrices. Similar known methods are based on properties of generator matrices. However some codes are specified via control matrices, for example low density parity check codes. The method proposed in this letter could be applied to some of them directly. This is illustrated in this manuscript using example in which a run length limited low density parity check code is obtained from Gallager code.
3
An, Youngeun, Ji Min Lee e Jongan Park. "Object Recognize by Column Vector Based on Rearrange Chain-Code". Applied Mechanics and Materials 20-23 (gennaio 2010): 768–73. http://dx.doi.org/10.4028/www.scientific.net/amm.20-23.768.
Testo completoAbstract (sommario):
This study deals with how to retrieve images using a rearranged chain-code based column vector. The chain-code expresses objects or boundaries of areas in straight chains with fixed direction and length, and encodes the final boundary, which is sensitive to rotated images. This study, therefore, works with chain-codes of eight directions in images and uses differences between values of chain-codes to obtain newly-rearranged chain-codes for image retrieval.
4
Tjalkens, T. J., e F. M. J. Willems. "A universal variable-to-fixed length source code based on Lawrence's algorithm". IEEE Transactions on Information Theory 38, n. 2 (marzo 1992): 247–53. http://dx.doi.org/10.1109/18.119684.
Testo completo
5
ARIMURA, Mitsuharu. "A Variable-to-Fixed Length Lossless Source Code Attaining Better Performance than Tunstall Code in Several Criterions". IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E101.A, n. 1 (2018): 249–58. http://dx.doi.org/10.1587/transfun.e101.a.249.
Testo completo
6
Puppe, V. "Group Actions and Codes". Canadian Journal of Mathematics 53, n. 1 (1 febbraio 2001): 212–24. http://dx.doi.org/10.4153/cjm-2001-009-0.
Testo completoAbstract (sommario):
AbstractA 2-action with “maximal number of isolated fixed points” (i.e., with only isolated fixed points such that dimk(⊕iHi (M; k)) = |M2|, k = ) on a 3-dimensional, closed manifold determines a binary self-dual code of length = . In turn this code determines the cohomology algebra H*(M; k) and the equivariant cohomology . Hence, from results on binary self-dual codes one gets information about the cohomology type of 3-manifolds which admit involutions with maximal number of isolated fixed points. In particular, “most” cohomology types of closed 3-manifolds do not admit such involutions. Generalizations of the above result are possible in several directions, e.g., one gets that “most” cohomology types (over ) of closed 3-manifolds do not admit a non-trivial involution.
7
Sharov, Sergey, e Sergey Tolmachev. "Search for binary code sequences with low autocorrelation sidelobes by the evolutionary method". Information and Control Systems, n. 1 (20 febbraio 2020): 44–53. http://dx.doi.org/10.31799/1684-8853-2020-1-44-53.
Testo completoAbstract (sommario):
Introduction: The parameters chosen for complex coded signals used in active radar systems of aircraft for detecting objects largelydetermines their qualitative characteristics and the possibility of covert operation. An important task in the design of such on-boardsystems is the formation of ensembles of pseudorandom-noise binary code sequences of a fixed length with predefined characteristics.Purpose: Search for PRN binary code sequences of a given length, optimal by the criterion of the minimum level of the sidelobes of theaperiodic autocorrelation function. Results: A procedure of search for binary code sequences with specified parameters based on theevolutionary approach is proposed. The minimum level of positive sidelobes of the autocorrelation function is used as a criterion forthe selection of code sequences. An additional restriction is imposed on the length of a substring of codes of the same character. Thepossibility of forming a representative array of sequences with the best ratio of the main peak of the aperiodic autocorrelation functionto its maximum positive sidelobe is shown on the example of 31-bit code sequences. An algorithm is proposed for generating a PRNseries of signals using the code sequences found. The Hamming distance is used as a measure of the difference between two binary codesequences in the series. The proposed approach is advantageous as compared to the well-known method of generating PRN signals basedon pseudorandom m-sequences. Practical relevance: The results obtained can be used in algorithms of airborne radar systems with ahigh range resolution to detect physical objects on the background of an underlying surface, for example, objects on the water surface.
8
Li, Fei, e Hong Yu. "ICD Coding from Clinical Text Using Multi-Filter Residual Convolutional Neural Network". Proceedings of the AAAI Conference on Artificial Intelligence 34, n. 05 (3 aprile 2020): 8180–87. http://dx.doi.org/10.1609/aaai.v34i05.6331.
Testo completoAbstract (sommario):
Automated ICD coding, which assigns the International Classification of Disease codes to patient visits, has attracted much research attention since it can save time and labor for billing. The previous state-of-the-art model utilized one convolutional layer to build document representations for predicting ICD codes. However, the lengths and grammar of text fragments, which are closely related to ICD coding, vary a lot in different documents. Therefore, a flat and fixed-length convolutional architecture may not be capable of learning good document representations. In this paper, we proposed a Multi-Filter Residual Convolutional Neural Network (MultiResCNN) for ICD coding. The innovations of our model are two-folds: it utilizes a multi-filter convolutional layer to capture various text patterns with different lengths and a residual convolutional layer to enlarge the receptive field. We evaluated the effectiveness of our model on the widely-used MIMIC dataset. On the full code set of MIMIC-III, our model outperformed the state-of-the-art model in 4 out of 6 evaluation metrics. On the top-50 code set of MIMIC-III and the full code set of MIMIC-II, our model outperformed all the existing and state-of-the-art models in all evaluation metrics. The code is available at https://github.com/foxlf823/Multi-Filter-Residual-Convolutional-Neural-Network.
9
Grošek, Otokar, Viliam Hromada e Peter Horák. "A Cipher Based on Prefix Codes". Sensors 21, n. 18 (17 settembre 2021): 6236. http://dx.doi.org/10.3390/s21186236.
Testo completoAbstract (sommario):
A prefix code, a P-code, is a code where no codeword is a prefix of another codeword. In this paper, a symmetric cipher based on prefix codes is proposed. The simplicity of the design makes this cipher usable for Internet of Things applications. Our goal is to investigate the security of this cipher. A detailed analysis of the fundamental properties of P-codes shows that the keyspace of the cipher is too large to mount a brute-force attack. Specifically, in this regard we will find bounds on the number of minimal P-codes containing a binary word given in advance. Furthermore, the statistical attack is difficult to mount on such cryptosystem due to the attacker’s lack of information about the actual words used in the substitution mapping. The results of a statistical analysis of possible keys are also presented. It turns out that the distribution of the number of minimal P-codes over all binary words of a fixed length is Gaussian.
10
Dinh, Nguyen Cong, Pham Thanh Hiep, Obinata Yua e Vu Van Son. "Controlling sequence length of DS-IR-UWB to enhance performance of multi-WBAN systems". Journal of Electrical Engineering 69, n. 5 (1 settembre 2018): 373–78. http://dx.doi.org/10.2478/jee-2018-0054.
Testo completoAbstract (sommario):
Abstract The international standard of wireless body area networks (WBANs), ie IEEE 802.15.6, was established in Feb. 2012, and this standard decided spreading code as a suppressing interference technology. However, the sequence length of spreading code is fixed, hence it is difficult to guarantee secure communications due to noise and interference from other WBANs. In this paper, we propose utilizing direct sequence impulse radio ultra wideband (DS-IR-UWB) for multi-WBAN systems, and then analyze multi-WBAN systems theoretically, derive equations of inter-WBAN interference, packet error rate (PER) and throughput. Furthermore, to guarantee secure communications, the desired PER is introduced, and then an algorithm is proposed to take the control of sequence length of DS-IR-UWB in order to ensure that the PER of system is always below the desired PER while maximizing the throughput. The numerical evaluation shows that the sequence length of proposed control method is changed according to the SNR and the number of WBANs, it lets the proposed algorithm of control of sequence length outperform the conventional fixed sequence length method.
11
Sabri, Ahmad, e Vincent Vajnovszki. "On the exhaustive generation of generalized ballot sequences in lexicographic and Gray code order". Pure Mathematics and Applications 28, n. 1 (1 ottobre 2019): 109–19. http://dx.doi.org/10.1515/puma-2015-0035.
Testo completoAbstract (sommario):
Abstract A generalized (resp. p-ary) ballot sequence is a sequence over the set of non-negative integers (resp. integers less than p) where in any of its prefixes each positive integer i occurs at most as often as any integer less than i. We show that the Reected Gray Code order induces a cyclic 3-adjacent Gray code on both, the set of fixed length generalized ballot sequences and p-ary ballot sequences when p is even, that is, ordered list where consecutive sequences (regarding the list cyclically) differ in at most 3 adjacent positions. Non-trivial efficient generating algorithms for these ballot sequences, in lexicographic order and for the obtained Gray codes, are also presented.
12
Tian, Yunke, Yong Bai e Dake Liu. "Low-Latency QC-LDPC Encoder Design for 5G NR". Sensors 21, n. 18 (18 settembre 2021): 6266. http://dx.doi.org/10.3390/s21186266.
Testo completoAbstract (sommario):
In order to meet the low latency and high throughput requirements of data transmission in 5th generation (5G) New Radio (NR), it is necessary to minimize the low power encoding hardware latency on transmitter and achieve lower base station power consumption within a fixed transmission time interval (TTI). This paper investigates parallel design and implementation of 5G quasi-cyclic low-density parity-check (QC-LDPC) codes encoder. The designed QC-LDPC encoder employs a multi-channel parallel structure to obtain multiple parity check bits and thus reduce encoding latency significantly. The proposed encoder maps high parallelism encoding algorithms to a configurable circuit architecture, achieving flexibility and support for all 5G NR code length and code rate. The experimental results show that under the 800 MHz system frequency, the achieved data throughput ranges from 62 to 257.9 Gbps, and the maximum code length encoding time under base graph 1 (BG1) is only 33.75 ns, which is the critical encoding time of our proposed encoder. Finally, our proposed encoder was synthesized on SMIC 28 nm CMOS technology; the result confirmed the effectiveness and feasibility of our design.
13
Saleem, Huda, Huda Albermany e Husein Hadi. "Proposed Method to Generated Strong Keys by Fuzzy Extractor And Biometric". International Journal of Engineering & Technology 7, n. 3.27 (15 agosto 2018): 129. http://dx.doi.org/10.14419/ijet.v7i3.27.17672.
Testo completoAbstract (sommario):
The typical scheme used to generated cryptographic key is a fuzzy extractor. The fuzzy extractor is the extraction of a stable data from biometric data or noisy data based on the error correction code (ECC) method. Forward error correction includes two ways are blocked and convolutional coding used for error control coding. “Bose_Chaudhuri_Hocquenghem” (BCH) is one of the error correcting codes employ to correct errors in noise data. In this paper use fuzzy extractor scheme to find strong key based on BCH coding, face recognition data used SVD method and hash function. Hash_512 converted a string with variable length into a string of fixed length, it aims to protect information against the threat of repudiation.
14
Karad, Avinash, e Shailja Kadam. "MUL-TIBIOMETRIC PATTERN RETRIEVAL USING INDEX CODE TO IMPROVE RESPONSE TIME". International Journal of Engineering Technologies and Management Research 3, n. 4 (30 gennaio 2020): 1–13. http://dx.doi.org/10.29121/ijetmr.v3.i4.2016.58.
Testo completoAbstract (sommario):
In a biometric identification system, the identity corresponding to the input data (probe) is typically determined by comparing it against the templates of all identities in a database (gallery). Exhaustive matching against a large number of identities increases the response time of the system and may also reduce the accuracy of identification. Onaway to reduce the response time is by designing biometric templates that allow for rapid matching, as in the case of Iris Codes. An alternative approach is to limit the number of identities against which matching is performed based on criteria that are fast to evaluate. We propose a method for generating fixed-length codes for indexing biometric databases. An index code is constructed by computing match scores between a biometric image and a fixed set of reference images. Candidate identities are retrieved based on the similarity between the index code of the probe image and those of the identities in the database. The proposed technique can be easily extended to retrieve pertinent identities from multimodal databases. Experiments on a chimeric face and fingerprint bimodal database resulted in an 84% average reduction in the search space at a hit rate of 100%. These results suggest that the proposed indexing scheme has the potential to substantially reduce the response time without compromising the accuracy of identification.
15
Joundan, Issam Abderrahman, Said Nouh, Mohamed Azouazi e Abdelwahed Namir. "A new efficient way based on special stabilizer multiplier permutations to attack the hardness of the minimum weight search problem for large BCH codes". International Journal of Electrical and Computer Engineering (IJECE) 9, n. 2 (1 aprile 2019): 1232. http://dx.doi.org/10.11591/ijece.v9i2.pp1232-1239.
Testo completoAbstract (sommario):
<span>BCH codes represent an important class of cyclic error-correcting codes; their minimum distances are known only for some cases and remains an open NP-Hard problem in coding theory especially for large lengths. This paper presents an efficient scheme ZSSMP (Zimmermann Special Stabilizer Multiplier Permutation) to find the true value of the minimum distance for many large BCH codes. The proposed method consists in searching a codeword having the minimum weight by Zimmermann algorithm in the sub codes fixed by special stabilizer multiplier permutations. These few sub codes had very small dimensions compared to the dimension of the considered code itself and therefore the search of a codeword of global minimum weight is simplified in terms of run time complexity. ZSSMP is validated on all BCH codes of length 255 for which it gives the exact value of the minimum distance. For BCH codes of length 511, the proposed technique passes considerably the famous known powerful scheme of Canteaut and Chabaud used to attack the public-key cryptosystems based on codes. ZSSMP is very rapid and allows catching the smallest weight codewords in few seconds. By exploiting the efficiency and the quickness of ZSSMP, the true minimum distances and consequently the error correcting capability of all the set of 165 BCH codes of length up to 1023 are determined except the two cases of the BCH(511,148) and BCH(511,259) codes. The comparison of ZSSMP with other powerful methods proves its quality for attacking the hardness of minimum weight search problem at least for the codes studied in this paper.</span>
16
Mervartová, Jana. "The amendment of the Labour Code". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 60, n. 2 (2012): 511–16. http://dx.doi.org/10.11118/actaun201260020511.
Testo completoAbstract (sommario):
The amendment of the Labour Code, No. 365/2011 Coll., effective as from 1st January 2012, brings some of fundamental changes in labour law. The amendment regulates relation between the Labour Code and the Civil Code; and is also formulates principles of labour law relations newly. The basic period by fixed-term contract of employment is extended and also frequency its conclusion is limited. The length of trial period and the amount of redundancy payment are graduated. An earlier legislative regulation which an employee is temporarily assign to work for different employer has been returned. The number of hours by agreement to perform work is increased. The monetary compensation by competitive clause is reduced. The other changes are realised in part of collective labour law. The authoress of article notifies of the most important changes. She compares new changes of the Labour Code and former legal system and she also evaluates their advantages and disadvantages. The main objective of changes ensures labour law relations to be more flexible. And it should motivate creation of new jobs opening by employers. Amended provisions are aimed to reduction expenses of employers under the reform of the public finances. Also changes are expected in the Labour Code in connection with the further new Civil Code.
17
Kavitha, T., e K. Jayasankar. "Ideal Huffman Code for Lossless Image Compression for Ubiquitous Access". Indonesian Journal of Electrical Engineering and Computer Science 12, n. 2 (1 novembre 2018): 765. http://dx.doi.org/10.11591/ijeecs.v12.i2.pp765-774.
Testo completoAbstract (sommario):
<p>Compression technique is adopted to solve various big data problems such as storage and transmission. The growth of cloud computing and smart phone industries has led to generation of huge volume of digital data. Digital data can be in various forms as audio, video, images and documents. These digital data are generally compressed and stored in cloud storage environment. Efficient storing and retrieval mechanism of digital data by adopting good compression technique will result in reducing cost. The compression technique is composed of lossy and lossless compression technique. Here we consider Lossless image compression technique, minimizing the number of bits for encoding will aid in improving the coding efficiency and high compression. Fixed length coding cannot assure in minimizing bit length. In order to minimize the bits variable Length codes with prefix-free codes nature are preferred. However the existing compression model presented induce high computing overhead, to address this issue, this work presents an ideal and efficient modified Huffman technique that improves compression factor up to 33.44% for Bi-level images and 32.578% for Half-tone Images. The average computation time both encoding and decoding shows an improvement of 20.73% for Bi-level images and 28.71% for Half-tone images. The proposed work has achieved overall 2% increase in coding efficiency, reduced memory usage of 0.435% for Bi-level images and 0.19% for Half-tone Images. The overall result achieved shows that the proposed model can be adopted to support ubiquitous access to digital data.</p>
18
Sanz, J. M., E. R. McFarland, N. L. Sanger, T. F. Gelder e R. H. Cavicchi. "Design and Performance of a Fixed, Nonaccelerating Guide Vane Cascade That Operates Over an Inlet Flow Angle Range of 60 Deg". Journal of Engineering for Gas Turbines and Power 107, n. 2 (1 aprile 1985): 477–84. http://dx.doi.org/10.1115/1.3239753.
Testo completoAbstract (sommario):
A unique set of wind tunnel guide vanes are designed with an inverse design code and analyzed with a panel method and an integral boundary layer code developed at the NASA Lewis Research Center. The fixed guide vanes, 80 ft long with 6-ft chord length, were designed for the NASA Ames 40 × 80/80 × 120 ft Wind Tunnel. Low subsonic flow is accepted over a 60 deg range of inlet angle from either the 40 × 80 leg or the 80 × 120 leg of the wind tunnel, and directed axially into the main leg of the tunnel where drive fans are located. Experimental tests of 1/10-scale models were conducted to verify design calculations.
19
Zhang, Hai Feng, e Chang Dong Xu. "Design of Remote Control Parking Lock Based on KEELOQ Encryption Technology". Applied Mechanics and Materials 643 (settembre 2014): 21–24. http://dx.doi.org/10.4028/www.scientific.net/amm.643.21.
Testo completoAbstract (sommario):
In most of current implementation scheme of remote control parking lock, fixed encoding chips are widely used. Due to its poor security and limited encoding length, it is easy to invade the system by “copying and retransmitting” “scanning and tracking”. In this paper, a hopping code technology based on non-linear shift register technology is utilized. This scheme ensures that the code sent by the transmitter each time is random, non-repeated and irregular, improving the security and immunity of the parking lock effectively. When the software and hardware of parking lock are designed based on PIC16F690 microcontroller, the security of the whole system has been well verified.
20
Patidar, H., e G. K. Mahanti. "Design of Non-Uniformly Spaced Circular Arrays of Parasitic Dipoles for Lower Side Lobe Level with Maximum Directivity". Advanced Electromagnetics 7, n. 1 (10 febbraio 2018): 51–56. http://dx.doi.org/10.7716/aem.v7i1.642.
Testo completoAbstract (sommario):
This paper presents a new approach for circular array of parasitic dipoles composed by one active dipole for reduction of side lobe level with maximum directivity including mutual coupling. The desired goal is obtained by changing the spacing between the parasitic elements and length of the parasitic elements while the position and length of driven element is fixed. In addition to it, reflection coefficient (RC) of the driven element is kept closer to the specified value. Matlab based method of moment code is used to evaluate the performance of circular antenna designs generated by QPSO algorithm. Two examples are presented to show the effectiveness of this proposed approach.
21
Cyganek, Bogusław, e Katarzyna Socha. "Computationally Efficient Methods of Approximations of the S-Shape Functions for Image Processing and Computer Graphics Tasks". Image Processing & Communications 16, n. 1-2 (1 gennaio 2011): 19–28. http://dx.doi.org/10.2478/v10248-012-0002-6.
Testo completoAbstract (sommario):
Computationally Efficient Methods of Approximations of the S-Shape Functions for Image Processing and Computer Graphics Tasks The paper describes a number of methods for approximation of the S-shape functions, frequently used in computer graphics or image processing. The main focus is on efficient software and hardware implementations. We present original code for the high and low level languages which implement different approximations of the S-shape functions. Additionally we introduce the FixedFor<> template class which fills the gap of efficient representation of different length fixed-point data formats in C++.
22
Larbi, A. B. "A New Design of a (3D) Fresnel Collector With Fixed Mirrors and Tracking Absorber". Journal of Solar Energy Engineering 122, n. 2 (1 maggio 2000): 63–68. http://dx.doi.org/10.1115/1.1286364.
Testo completoAbstract (sommario):
In this paper we developed model of a (3D) Fresnel collector with fixed mirrors and tracking absorber which approximates the optical behavior of a fixed spherical collector (hemispherical bowl). The aim of the study is to investigate the possibility of using this type of installation for applications in medium temperature processes (200—300°C). Via a computer simulation which includes ray-tracing, we evaluate the sensitivity of the geometric concentration ratio to: concentrator design parameters and the option of using curved versus flat elementary mirrors. The developed computer code permits the optimization of the concentrator reflecting area, the focal length (or rim half-angle), and the dimensions and number of reflecting elementary mirrors. The (3D) Fresnel collectors can be a practical alternative to spherical collectors (hemispherical bowl). Capital and maintenance costs can be significantly lower than for spherical collectors, but with reduced energy delivery. [S0199-6231(00)00302-6]
23
Challa, RatnaKumari, e VijayaKumari Gunta. "A Modified Symmetric Key Fully Homomorphic Encryption Scheme Based on Read-Muller Code". Baghdad Science Journal 18, n. 2(Suppl.) (20 giugno 2021): 0899. http://dx.doi.org/10.21123/bsj.2021.18.2(suppl.).0899.
Testo completoAbstract (sommario):
Homomorphic encryption became popular and powerful cryptographic primitive for various cloud computing applications. In the recent decades several developments has been made. Few schemes based on coding theory have been proposed but none of them support unlimited operations with security. We propose a modified Reed-Muller Code based symmetric key fully homomorphic encryption to improve its security by using message expansion technique. Message expansion with prepended random fixed length string provides one-to-many mapping between message and codeword, thus one-to many mapping between plaintext and ciphertext. The proposed scheme supports both (MOD 2) additive and multiplication operations unlimitedly. We make an effort to prove the security of the scheme under indistinguishability under chosen-plaintext attack (IND-CPA) through a game-based security proof. The security proof gives a mathematical analysis and its complexity of hardness. Also, it presents security analysis against all the known attacks with respect to the message expansion and homomorphic operations.
24
Elelwi, M., M. A. Kuitche, R. M. Botez e T. M. Dao. "Comparison and analyses of a variable span-morphing of the tapered wing with a varying sweep angle". Aeronautical Journal 124, n. 1278 (4 marzo 2020): 1146–69. http://dx.doi.org/10.1017/aer.2020.19.
Testo completoAbstract (sommario):
ABSTRACTThis work presents a comparative study of design and development, in addition, of analyses of variable span morphing of the tapered wing (VSMTW) for the unmanned aerial vehicle (UAV). The proposed concept consists in the sliding of the inner section into the fixed part along the wing with varying the angle of the inner section inside the fixed part (parallel with the leading edge and the moving-wing axis is coincident to the fixed-wing axis) within two configurations. The wing design is based on a NACA 4412 aerofoil with the root chord of 0.675m and the tip chord of 0.367m for the fixed segment and 0.320m for the moving segment. Morphing wing analysis occurs at three selected locations that have been specified for extending and modifying span length by (25%, 50%, and 75%) of its original length to fulfill various flight mission requirements. The main objective of this paper is to compare the aerodynamic characteristics for several span lengths and sweep angles and to find their most efficient combinations. The wing is optimised for different velocities during all phases of flight (min speed, loiter, cruise, and max speed) which are 17, 34, 51, and 68m/s, respectively. The analyses are performed by computing forces (drag and lift) and moments at various altitudes, such as at the sea level, at 5,000 and 10,000ft. Two-dimensional aerodynamic analyses are carried out using XFLR5 code, and the ANSYS Fluent solver is used for investigating the flow field on the three-dimensional wing structure. It has been observed that a variable span morphing of tapered wing technology with a variable sweep angle can deliver up to 32.93% improved aerodynamic efficiency. This concept design can also be used for the aircraft roll motion technique instead of conventional control devices. Furthermore, the range flight mission increases up to 46.89% when the wing is placed at its full length compared to an original position. Finally, it has been concluded from this study that the wing design is more sensitive to the changing angle of the inner section and more efficient in terms of aerodynamic characteristics.
25
CINQUE, LUIGI, SERGIO DE AGOSTINO, FRANCO LIBERATI e BART WESTGEEST. "A SIMPLE LOSSLESS COMPRESSION HEURISTIC FOR GREY SCALE IMAGES". International Journal of Foundations of Computer Science 16, n. 06 (dicembre 2005): 1111–19. http://dx.doi.org/10.1142/s0129054105003686.
Testo completoAbstract (sommario):
In this paper, we show a simple lossless compression heuristic for gray scale images. The main advantage of this approach is that it provides a highly parallelizable compressor and decompressor. In fact, it can be applied independently to each block of 8×8 pixels, achieving 80 percent of the compression obtained with LOCO-I (JPEG-LS), the current lossless standard in low-complexity applications. The compressed form of each block employs a header and a fixed length code, and the sequential implementations of the encoder and decoder are 50 to 60 percent faster than LOCO-I.
26
PM, Nishad, e R. Manicka Chezian. "A Vital Approach to compress the Size of DNA Sequence using LZW (Lempel-Ziv-Welch) with Fixed Length Binary Code and Tree Structure". International Journal of Computer Applications 43, n. 1 (30 aprile 2012): 7–9. http://dx.doi.org/10.5120/6065-8193.
Testo completo
27
Ma, Shu Fen, e Xie Dong Zhang. "Parametric Analysis on Shear Lag Effects of Box-Girder Beam". Applied Mechanics and Materials 351-352 (agosto 2013): 152–55. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.152.
Testo completoAbstract (sommario):
In order to study the influencing parameters of the shear lag effects on the box-girder beam, the effective width was analyzed by the ways of looking up the present code and formula. Taking the simply supported and cantilever girder as the example, the parameter sensitivity was studied, such as width/span, cantilever length and span. The results showed that the shear lag effect of mid-span beam is small but the support beam is outstanding; the fixed amount relationship of the parameters and the shear lag effects was put forward. The conclusions will be useful for the design and construction of the box girder bridge.
28
Lo, Rong-Chin, Tung-Tai Kuo, Ren-Guey Lee, Yuan-Hao Chen e Chuan Chin Lim. "EVOKED POTENTIAL PRIMITIVES OF RAT MOTOR CORTEX SIGNAL ANALYSIS BASED ON ITERATED FUNCTION SYSTEMS". Biomedical Engineering: Applications, Basis and Communications 32, n. 04 (29 luglio 2020): 2050033. http://dx.doi.org/10.4015/s1016237220500337.
Testo completoAbstract (sommario):
The function of the brain has been the focus of neuroscience studies for nearly half a century. The studies found that the evoked potential signals of the motor cortex are the main source to command action. An action signal is composed of several signal primitives that are mainly generated by the motor cortex. It was found that signal primitives of the motor cortex can be produced by several fixed rules and a group of codes called iterated function systems (IFS) code. The goal of our research is to find the relationships between the signal primitives of the motor cortex and actions. We recorded the action signals of the rat motor cortex using 8-channel micro-electrodes and used independent component analysis (ICA) to find the independent source signals called signal primitives. Then, the IFS algorithm was used to find the signal primitive codes, which is the IFS code. The experimental results showed that the source signals of actions produce the IFS rules and a set of codes by the IFS algorithm and conversely, using the IFS rules and the set of codes can reconstruct the source signals. Every 20-character length of action signals will generate unique 6-character IFS codes, meaning that the action signals can be replaced with IFS codes to achieve the compression. We found that the IFS rules and codes can be used to represent different cortex commands which have distinct IFS codes that can be used to classify the movements of rat. The classification result reached 78.75% for rough movement and nearly 50% for subtle movement, where the rough movement is that the rat performs two motions and the subtle movement is three motions. This result shows that the motor cortex command can consist of distinct signal primitives and the huge file size of the motor cortex command is reduced three times by the IFS algorithm.
29
SHEN, LINLIN, LI BAI e ZHEN JI. "FPCODE: AN EFFICIENT APPROACH FOR MULTI-MODAL BIOMETRICS". International Journal of Pattern Recognition and Artificial Intelligence 25, n. 02 (marzo 2011): 273–86. http://dx.doi.org/10.1142/s0218001411008555.
Testo completoAbstract (sommario):
Although face recognition technology has progressed substantially, its performance is still not satisfactory due to the challenges of great variations in illumination, expression and occlusion. This paper aims to improve the accuracy of personal identification, when only few samples are registered as templates, by integrating multiple modal biometrics, i.e. face and palmprint. We developed in this paper a feature code, namely FPCode, to represent the features of both face and palmprint. Though feature code has been used for palmprint recognition in literature, it is first applied in this paper for face recognition and multi-modal biometrics. As the same feature is used, fusion is much easier. Experimental results show that both feature level and decision level fusion strategies achieve much better performance than single modal biometrics. The proposed approach uses fixed length 1/0 bits coding scheme that is very efficient in matching, and at the same time achieves higher accuracy than other fusion methods available in literature.
30
Obe, Tayo, Chinwuba Arum e Oladimeji Olalusi. "Optimization of single-span single-storey portal frame buildings". Facta universitatis - series: Architecture and Civil Engineering 17, n. 4 (2019): 359–76. http://dx.doi.org/10.2298/fuace190610021o.
Testo completoAbstract (sommario):
Many structural designs are done without comprehensive consideration for achieving optimum design. To achieve minimum mass optimization, a mathematical model was developed in this study and subjected to British Standard (BS 5950) code requirements for structural integrity as constraints. Visual basic application (VBA) codes were written into a spreadsheet environment to implement the model. The developed optimization model was validated using different sample shed structures of same volume (729m?) but of different height to span to length (H: b: L) ratios which were obtained using the Ratio method and the Step size method. The best parameter ratio of height to length to breadth obtained was 1:1:1 which is similar to what was obtained by other authors. Parametric design case study analysis was also performed for three different design situations with a given span b, heights H and h and frame spacing S. The minimum masses of steel for a fixed plan area of the buildings were obtained for each of the three scenarios. It is recommended that design engineers should consider varying major frame parameters such as frame spacing and heights at pre-design stages in order to obtain optimal values of parameters which will ensure economical structures.
31
Nouroozi, M., M. Pasandidehfard e M. H. Djavareshkian. "Simulation of Partial and Supercavitating Flows around Axisymmetric and Quasi-3D Bodies by Boundary Element Method Using Simple and Reentrant Jet Models at the Closure Zone of Cavity". Mathematical Problems in Engineering 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/1593849.
Testo completoAbstract (sommario):
A fixed-length Boundary Element Method (BEM) is used to investigate the super- and partial cavitating flows around various axisymmetric bodies using simple and reentrant jet models at the closure zone of cavity. Also, a simple algorithm is proposed to model the quasi-3D cavitating flows over elliptical-head bodies using the axisymmetric method. Cavity and reentrant jet lengths are the inputs of the problem and the cavity shape and cavitation number are some of the outputs of this simulation. A numerical modeling based on Navier-Stokes equations using commercial CFD code (Fluent) is performed to evaluate the BEM results (in 2D and 3D cases). The cavitation properties approximated by the present research study (especially with the reentrant jet model) are very close to the results of other experimental and numerical solutions. The need for a very short time (only a few minutes) to reach the desirable convergence and relatively good accuracy are the main advantages of this method.
32
Maulunida, Restu, e Achmad Solichin. "Optimization of LZW Compression Algorithm With Modification of Dictionary Formation". IJCCS (Indonesian Journal of Computing and Cybernetics Systems) 12, n. 1 (31 gennaio 2018): 73. http://dx.doi.org/10.22146/ijccs.28707.
Testo completoAbstract (sommario):
At present, the need to access the data have been transformed into digital data, and its use has been growing very rapidly. This transformation is due to the use of the Internet is growing very rapidly, and also the development of mobile devices are growing massively. People tend to store a lot of files in their storage and transfer files from one media to another media. When approaching the limit of storage media, the fewer files that can be stored. A compression technique is required to reduce the size of a file. The dictionary coding technique is one of the lossless compression techniques, LZW is an algorithm for applying coding dictionary compression techniques. In the LZW algorithm, the process of forming a dictionary uses a future based dictionary and encoding process using the Fixed Length Code. It allows the encoding process to produce a sequence that is still quite long. This study will modify the process of forming a dictionary and use Variable Length Code, to optimize the compression ratio. Based on the test using the data used in this study, the average compression ratio for LZW algorithm is 42,85%, and our proposed algorithm is 38,35%. It proves that the modification of the formation of the dictionary we proposed has not been able to improve the compression ratio of the LZW algorithm.
33
Song, N., S. Alexeeva, T. Sitnova, L. Wang, F. Grupp e G. Zhao. "Impact of the convective mixing-length parameter α on stellar metallicity". Astronomy & Astrophysics 635 (marzo 2020): A176. http://dx.doi.org/10.1051/0004-6361/201937110.
Testo completoAbstract (sommario):
Context. Mixing-length theory is used to treat stellar convection. As a simulation in one-dimensional stellar atmospheres models, the mixing-length parameter α is calibrated from the Sun and then applied to other stars. However, there is no strong evidence to suggest that α should be the same for stars of different evolutionary stages. Aims. We evaluate the impact of the α value on the metallicity of different types of stars and investigate the correlation between the metallicity discrepancy (Δ[Fe∕H]) and stellar parameters (Teff, log g). Methods. We selected ten well-studied field stars and one open cluster of nine members for which high-resolution and high signal-to-noise spectra are available. The model atmospheres were calculated with the code MAFAGS-OS. We derived iron abundances from Fe I and Fe II lines both under local thermodynamic equilibrium and non-LTE conditions using a spectrum synthesis method. After deriving [Fe/H] for each line, we calculated Δ[Fe∕H] with two different α values, fixed solar-calibrated α, and α obtained for each star individually. Finally, we investigated the correlation between Δ[Fe∕H] caused by revised α with stellar parameters. Results. For FGK dwarf stars, the Δ[Fe∕H] caused by the α correction is less than 0.02 dex, while for turn-off and giant stars, the Δ[Fe∕H] values are no more than 0.03 dex, which are lower than typical uncertainties in metallicity. For main-sequence stars, Δ[Fe∕H] versus Teff and Δ[Fe∕H] versus log g are well fit by linear relations.
34
Murdiansyah, Lukman, Robby Permata e Donald Essen. "Modal pushover analysis on reinforced concrete arch bridge to estimate seismic responses". E3S Web of Conferences 156 (2020): 03005. http://dx.doi.org/10.1051/e3sconf/202015603005.
Testo completoAbstract (sommario):
This paper presents an evaluation study of the performance of reinforced concrete arch bridge structures under earthquake load. The study is aimed to investigate the seismic performance of Wreksodiningrat Bridge, located in the province of Yogyakarta, Indonesia. This bridge is a three spans reinforced concrete arch bridge with a main span length of 75 m and two side spans with a length of 35 m, respectively. This study is a part of a large project carried out by the Ministry of Public Works to study the impact of the new 2016 Indonesia Seismic Design Code for Bridges (SNI 2833:2016). The main objective of this paper is to determine the displacement demands due to earthquake load based on the new seismic code design for bridges, SNI 2833:2016. In addition, demand capacity ratios (D/C) of the main structural components, such as the compression arch and main column (pier) at the fixed support, are also reviewed in this paper. The analysis was carried out using nonlinear modal pushover analysis. The arch bridge modeling is three dimensional, where structural elements such as beams, columns, and compression arches are modeled as frame elements. The plastic hinges are modeled as fiber hinges with unconfined and confined concrete material stress-strain relationship following Mander formula. The analysis result shows that the displacement demands of the bridge are 2.9 cm and 20 cm in the longitudinal and transverse direction, respectively. The D/C ratios of the compression arch due to demand earthquake load are 0.74 and 0.95 in the longitudinal and transverse direction of the bridge, while the D/C ratios of the pier are 0.15 and 0.80 in the longitudinal and transverse direction. Based on the above results, it is concluded that the studied bridge is able to withstand the seismic load requirements in the new Indonesia Seismic Design Code.
35
Akhoundi, Behnam, Mojtaba Nabipour, Faramarz Hajami, Shahab S. Band e Amir Mosavi. "Calculating Filament Feed in the Fused Deposition Modeling Process to Correctly Print Continuous Fiber Composites in Curved Paths". Materials 13, n. 20 (9 ottobre 2020): 4480. http://dx.doi.org/10.3390/ma13204480.
Testo completoAbstract (sommario):
Fused deposition modeling (FDM) is a popular additive manufacturing (AM) method that has attracted the attention of various industries due to its simplicity, cheapness, ability to produce complex geometric shapes, and high production speed. One of the effective parameters in this process is the filament feed presented in the production G-code. The filament feed is calculated according to the layer height, the extrusion width, and the length of the printing path. All required motion paths and filling patterns created by commercial software are a set of straight lines or circular arcs placed next to each other at a fixed distance. In special curved paths, the distance of adjacent paths is not equal at different points, and due to the weakness of common commercial software, it is not possible to create curved paths for proper printing. The creation of a special computer code that can be used to make various functions of curved paths was investigated in this study. The filament feed parameter was also studied in detail. Next, by introducing a correction technique, the filament feed was changed on the curved path to uniformly distribute the polymer material. Variable-stiffness composite samples consisting of curved fibers can be produced with the proposed method. The high quality of the printed samples confirms the suggested code and technique.
36
Tenreiro Machado, J. A., António C. Costa e Maria Dulce Quelhas. "Can Power Laws Help Us Understand Gene and Proteome Information?" Advances in Mathematical Physics 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/917153.
Testo completoAbstract (sommario):
Proteins are biochemical entities consisting of one or more blocks typically folded in a 3D pattern. Each block (a polypeptide) is a single linear sequence of amino acids that are biochemically bonded together. The amino acid sequence in a protein is defined by the sequence of a gene or several genes encoded in the DNA-based genetic code. This genetic code typically uses twenty amino acids, but in certain organisms the genetic code can also include two other amino acids. After linking the amino acids during protein synthesis, each amino acid becomes a residue in a protein, which is then chemically modified, ultimately changing and defining the protein function. In this study, the authors analyze the amino acid sequence using alignment-free methods, aiming to identify structural patterns in sets of proteins and in the proteome, without any other previous assumptions. The paper starts by analyzing amino acid sequence data by means of histograms using fixed length amino acid words (tuples). After creating the initial relative frequency histograms, they are transformed and processed in order to generate quantitative results for information extraction and graphical visualization. Selected samples from two reference datasets are used, and results reveal that the proposed method is able to generate relevant outputs in accordance with current scientific knowledge in domains like protein sequence/proteome analysis.
37
Somers, D. M., e J. L. Tangler. "Wind Tunnel Test of the S814 Thick Root Airfoil". Journal of Solar Energy Engineering 118, n. 4 (1 novembre 1996): 217–21. http://dx.doi.org/10.1115/1.2871781.
Testo completoAbstract (sommario):
The objective of this wind-tunnel test was to verify the predictions of the Eppler Airfoil Design and Analysis Code for a very thick airfoil having a high maximum lift coefficient designed to be largely insensitive to leading-edge roughness effects. The 24 percent thick S814 airfoil was designed with these characteristics to accommodate aerodynamic and structural considerations for the root region of a wind-turbine blade. In addition, the airfoil’s maximum lift-to-drag ratio was designed to occur at a high lift coefficient. To accomplish the objective, a two-dimensional wind tunnel test of the S814 thick root airfoil was conducted in January 1994 in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. Data were obtained with transition free and transition fixed for Reynolds numbers of 0.7, 1.0, 1.5, 2.0, and 3.0 × 106. For the design Reynolds number of 1.5 × 106, the maximum lift coefficient with transition free is 1.32, which satisfies the design specification. However, this value is significantly lower than the predicted maximum lift coefficient of almost 1.6. With transition fixed at the leading edge, the maximum lift coefficient is 1.22. The small difference in maximum lift coefficient between the transition-free and transition-fixed conditions demonstrates the airfoil’s minimal sensitivity to roughness effects. The S814 root airfoil was designed to complement existing NREL low maximum-lift-coefficient tip-region airfoils for rotor blades 10 to 15 meters in length.
38
Durairaj, Janani, Mehmet Akdel, Dick de Ridder e Aalt D. J. van Dijk. "Geometricus represents protein structures as shape-mers derived from moment invariants". Bioinformatics 36, Supplement_2 (dicembre 2020): i718—i725. http://dx.doi.org/10.1093/bioinformatics/btaa839.
Testo completoAbstract (sommario):
Abstract Motivation As the number of experimentally solved protein structures rises, it becomes increasingly appealing to use structural information for predictive tasks involving proteins. Due to the large variation in protein sizes, folds and topologies, an attractive approach is to embed protein structures into fixed-length vectors, which can be used in machine learning algorithms aimed at predicting and understanding functional and physical properties. Many existing embedding approaches are alignment based, which is both time-consuming and ineffective for distantly related proteins. On the other hand, library- or model-based approaches depend on a small library of fragments or require the use of a trained model, both of which may not generalize well. Results We present Geometricus, a novel and universally applicable approach to embedding proteins in a fixed-dimensional space. The approach is fast, accurate, and interpretable. Geometricus uses a set of 3D moment invariants to discretize fragments of protein structures into shape-mers, which are then counted to describe the full structure as a vector of counts. We demonstrate the applicability of this approach in various tasks, ranging from fast structure similarity search, unsupervised clustering and structure classification across proteins from different superfamilies as well as within the same family. Availability and implementation Python code available at https://git.wur.nl/durai001/geometricus.
39
MOHAMED, KHAIRI ASHOUR, e LÁSZLÓ PAP. "PERFORMANCE ANALYSIS OF FREQUENCY-HOPPED SPREAD-SPECTRUM PACKET RADIO NETWORKS PART II: UNSLOTTED MULTIPLE-ACCESS". Journal of Circuits, Systems and Computers 06, n. 05 (ottobre 1996): 453–74. http://dx.doi.org/10.1142/s0218126696000315.
Testo completoAbstract (sommario):
This paper is concerned with the performance analysis of unslotted frequency-hopped spread spectrum packet radio networks with Reed-Solomon forward error control coding. The following different network alternatives are analyzed in a unified manner (i) random/one-coincidence frequency hopping patterns, (ii) one/several code symbols per dwell interval, (iii) independent/dependent packet arrival processes, (iv) fixed/variable length packets. Joint probability generating functions for the pair-wise hit patterns and the effective multiple-access interference vector are determined for the different alternatives. Closed form formulae and expressions for packet capture probabilities are readily obtained from these generating functions. A direct proof is given that in the case of single symbol/dwell packets symbol errors, are asymptotically independent. Numerical results indicate that the unslotted networks outperform the corresponding slotted ones at low to moderate traffic levels, and the difference between the two networks is diminishing when the number of frequency bins is large.
40
Mayer, Helmut A. "ptGAs—Genetic Algorithms Evolving Noncoding Segments by Means of Promoter/Terminator Sequences". Evolutionary Computation 6, n. 4 (dicembre 1998): 361–86. http://dx.doi.org/10.1162/evco.1998.6.4.361.
Testo completoAbstract (sommario):
In this article we present work on chromosome structures for genetic algorithms (GAs) based on biological principles. Mainly, the influence of noncoding segments on GA behavior and performance is investigated. We compare representations with noncoding sequences at predefined, fixed locations with “junk” code induced by the use of promoter/terminator sequences (ptGAs) that define start and end of a coding sequence, respectively. AS one of the advantages of noncoding segments a few researchers have identified the reduction of the disruptive effects of crossover, and we solidify this argument by a formal analysis of crossover disruption probabilities for noncoding segments at fixed locations. The additional use of promoter/terminator sequences not only enables evolution of parameter values, but also allows for adaptation of number, size, and location of genes (problem parameters) on an artificial chromosome. Randomly generated chromosomes of fixed length carry different numbers of promoter/terminator sequences resulting in genes of varying size and location. Evolution of these ptGA chromosomes drives the number of parameters and their values to (sub)optimal solutions. Moreover, the formation of tightly linked building blocks is enhanced by self-organization of gene locations. We also introduce a new, nondisruptive crossover operator emerging from the ptGA gene structure with adaptive crossover rate, location, and number of crossover sites. For experimental comparisons of this genetic operator to conventional crossover in GAs, as well as properties of different ptGA chromosome structures, an artificial problem from the literature is utilized. Finally, the potential of ptGA is demonstrated on an NP-complete combinatorial optimization problem.
41
Shamal, Souad Jabbar, Luay Sadiq Al-Ansari, Ahmed Niameh Mehdy Alhusseny e Adel Gharib Nasser. "Roughness Effect on Thermo-Elasto-Hydrodynamic Performance of a 170ᵒ -Arc Partial Journal Bearing". Journal of Engineering 27, n. 1 (1 gennaio 2021): 16–34. http://dx.doi.org/10.31026/10.31026/j.eng.2021.01.02.
Testo completoAbstract (sommario):
In the current analysis, the effects of circumferential scratches along the inner surface of a 170ᵒ -arc partial journal bearing has been numerically investigated. Their impact on the thermo-elasto-hydrodynamic performance characteristics, including maximum pressure, temperature, deformation, and stress, has been examined thoroughly. The ANSYS Fluent CFD commercial code was employed to tackle the iterative solution of flow and heat transfer patterns in the fluid film domain. They are then applied to the ANSYS Static Structure solver to compute the deformation and stress resulted in the solid bearing zone. A wide range of operating conditions has been considered, including the eccentricity ratio ( ) and scratch depth ( ). In contrast, the bearing length-diameter ratio (L/D) and the rotation speed (N) have been fixed at 0.77 and 1500 rpm, respectively. The thermo-hydrodynamic pressure, temperature, stress, and deformation have all been computed. It was found that the scratch depth has a direct effect on the thermo-hydrodynamic performance of the partial bearings. Meanwhile, the deep central scratches are important, especially at scratch depth equal to 0.224 mm.
42
Cao, Shu Kun, Shang Wei Yang, Jing Bo Yin, Hui Zhang e Hai Long Deng. "Lengthening Steel-Work Hole Processing Machine Design Based on Open CNC System". Advanced Materials Research 181-182 (gennaio 2011): 685–90. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.685.
Testo completoAbstract (sommario):
This paper describes two schemes of lengthening steel structure hole processing machine tool. Their base length of lengthening steel structure hole processing machine tool is fixed and the column who can move around realizes the horizontal movement by dovetail slot and the screw. The former can realize that a machine can simultaneously process multiple holes after work-piece being clamped once. The latter is that machine tool can only process a single hole for the work-piece clamping, then process other holes by the mobile of the column and the spindle box. It is not only labor-saving and energy but is efficiency. Through the NC programming, the machine tool can fast install the parts and process four holes at the same time accurately. In allusion to all sorts of questions of the present NC programming using G, M code, lengthening steel structure hole processing machine tool based on open CNC is proposed in the paper, which can machining parts directly by using the corresponding computer modules and achieves information sharing of work-piece.
43
Laidoudi, H. "UPWARD FLOW AND HEAT TRANSFER AROUND TWO HEATED CIRCULAR CYLINDERS IN SQUARE DUCT UNDER AIDING THERMAL BUOYANCY". Journal of the Serbian Society for Computational Mechanics 14, n. 1 (30 giugno 2020): 113–23. http://dx.doi.org/10.24874/jsscm.2020.14.01.10.
Testo completoAbstract (sommario):
This paper presents a numerical investigation of mixed convection heat transfer around a pair of identical circular cylinders placed in side-by-side arrangement inside a square cavity of single inlet and outlet ports. The investigation provided the analysis of gradual effect of aiding thermal buoyancy on upward flow around cylinders and its effect on heat transfer rate. For that purpose, the governing equations involving continuity, momentum and energy are solved using the commercial code ANSYS-CFX. The distance between cylinders is fixed with half-length of cavity. The simulation is assumed to be in laminar, steady, incompressible flow within range of following conditions: Re = 1 to 40, Ri = 0 to 1 at Pr = 0.71. The main obtained results are shown in the form of streamline and isotherm contours in order to interpret the physical phenomena of flow and heat transfer. The average Nusselt number is also computed and presented. It was found that increase in Reynolds number and/or Richardson number increases the heat transfer. Also, aiding thermal buoyancy creates new form of counter-rotating zones between cylinders.
44
Shamal, Souad Jabbar, Luay Sadiq Al-Ansari, Ahmed Niameh Mehdy Alhusseny e Adel Gharib Nasser. "Roughness Effect on Thermo-Elasto-Hydrodynamic Performance of a 170ᵒ -Arc Partial Journal Bearing". Journal of Engineering 27, n. 1 (1 gennaio 2021): 16–34. http://dx.doi.org/10.31026/j.eng.2021.01.02.
Testo completoAbstract (sommario):
In the current analysis, the effects of circumferential scratches along the inner surface of a 170ᵒ -arc partial journal bearing has been numerically investigated. Their impact on the thermo-elasto-hydrodynamic performance characteristics, including maximum pressure, temperature, deformation, and stress, has been examined thoroughly. The ANSYS Fluent CFD commercial code was employed to tackle the iterative solution of flow and heat transfer patterns in the fluid film domain. They are then applied to the ANSYS Static Structure solver to compute the deformation and stress resulted in the solid bearing zone. A wide range of operating conditions has been considered, including the eccentricity ratio ( ) and scratch depth ( ). In contrast, the bearing length-diameter ratio (L/D) and the rotation speed (N) have been fixed at 0.77 and 1500 rpm, respectively. The thermo-hydrodynamic pressure, temperature, stress, and deformation have all been computed. It was found that the scratch depth has a direct effect on the thermo-hydrodynamic performance of the partial bearings. Meanwhile, the deep central scratches are important, especially at scratch depth equal to 0.224 mm.
45
Podoltsev, V. V. "Estimation of the probabilistic characteristics of the majority method for processing short segments of a pseudo-random sequence". Radio industry (Russia) 30, n. 1 (14 aprile 2020): 8–15. http://dx.doi.org/10.21778/2413-9599-2020-30-1-8-15.
Testo completoAbstract (sommario):
Simulation modeling of the processing method for pseudo-random sequence (PRS) short segments based on the majority tests gives the probability characteristics that are different from the results of a calculation using the Gaussian approximation. The simulation modeling shows that the probability of bit error decoding is changed discretely with the explicit minima and maxima for the length of the processed segment of the PRS. This is due to the fact that the decoder always uses a fixed test sequence, which is determined by the initial phase of the analyzer. Thus, the distribution of these checks determines the dependence of the bit error probability. On this basis, the paper conducts a theoretical study of the probability characteristics synchronization method based on the majority tests, taking into account the specifics of the PRS analyzer. The article formulates and solves the task of analyzing probabilistic characteristics of the majority method of processing short segments of the PRS, which required finding the probability of bit error of decoding. The analytical relations for the probability of bit error of decoding are obtained. The calculations and systematic analysis of the results are performed. It is shown that: with the increase in the length of the processed segment or the length of the valid section N the probability of error can be greater than the probability of destructive errors; the method based on the majority tests with a high probability of destructive errors has a significant advantage in the average code search time over the Ward’s method. Based on the obtained results a modification of the method that will provide the optimal choice of the length of the processed segment of PRS N will be offered in further studies.
46
Степанов, Олег, e Oleg Stepanov. "ELECTRONIC GOVERNMENT AS AN INSTRUMENT TO BE USED TO COUNTERACT CORRUPTION IN THE RUSSIAN FEDERATION". Journal of Foreign Legislation and Comparative Law 2, n. 4 (5 settembre 2016): 0. http://dx.doi.org/10.12737/21244.
Testo completoAbstract (sommario):
The article discusses the features and prospects relating to the development of technology of “electronic government” due to the use of electronic information systems and the introduction of scientific and practical turnover category “standard-setting action”. Events are interpreted as the expression of functional external relations of the subjects of the right to information through the use of the code which reflects the algorithm acts of such entities as the digital code of fixed length, which carries the regulatory information, reflecting more or less similar to the original legally significant situation. Based on the need for uniform accounting standards in judicial practice, it is important to optimize the use of such information in order to improve the efficiency of anti-corruption court. This state can promote the computer evaluation of the quality of the developed judicial act (judgment, ruling), connected with the development and creation of a comprehensive quality management system of judicial decisions based on the use of modern software and hardware. Integrated quality management system in judicial decisions should be composed of at least two groups of models: the first is to describe the boundary condition for the existence of society, and the second — human activity. This first group of models should be attributed to the number of basic and human activity unit must be built on the basis of established legal limits. This involves consideration of the process of preparation of the judicial act (decision, judgment) on the basis of the synthesis of the legal needs of society and the state with the parameters of human rights and freedoms.
47
Besserman, E., D. Teres, A. Logan, M. Brennan, S. Cleaves, R. Bayly, D. Brochis, B. Nemeth, J. Grare e D. Ngo. "Use of flexible intermediate and intensive care to reduce multiple transfers of patients". American Journal of Critical Care 8, n. 3 (1 maggio 1999): 170–79. http://dx.doi.org/10.4037/ajcc1999.8.3.170.
Testo completoAbstract (sommario):
OBJECTIVE: To test an alternative flexible approach to traditional fixed intermediate and intensive care to minimize transfers of patients. METHODS: Patients admitted to a 28-bed nursing unit with intermediate care potential and a 12-bed intensive care unit at a 300-bed teaching community hospital were studied. The group included 524 patients with a discharge diagnosis code for mechanical ventilation. During eight 3-week cycles, 1073 transfers of patients were tabulated. A plan-do-study-act method was used to improve weaning from mechanical ventilation and reduce the number of inappropriate days in intensive care. Admissions and transfers to the 2 units for all patients during the eight 3-week cycles were compared over time. Length of stay and mortality were noted for all patients treated with conventional and noninvasive ventilation. RESULTS: Direct admissions to the flexible intermediate unit increased with no overall change in admissions to the intensive care unit. Fewer patients needed conventional ventilation, and more in both units were treated with noninvasive ventilation. The median number of transfers per patient treated with mechanical ventilation decreased from 1.94 to 1.20. Length of stay and mortality also decreased among such patients. Some cost savings were attributable to the decrease in the number of transfers. Transfers out of the hospital directly from the intensive care unit increased from 2.24% to 4.43%. CONCLUSIONS: In a community teaching hospital, flexible care policies decreased the number of in-hospital transfers of patients treated with mechanical ventilation.
48
Gomes, M. N., C. D. Nascimento, B. L. Bonafini, E. D. Santos, L. A. Isoldi e L. A. O. Rocha. "TWO-DIMENSIONAL GEOMETRIC OPTIMIZATION OF AN OSCILLATING WATER COLUMN CONVERTER IN LABORATORY SCALE". Revista de Engenharia Térmica 11, n. 1-2 (31 dicembre 2012): 30. http://dx.doi.org/10.5380/reterm.v11i1-2.61996.
Testo completoAbstract (sommario):
The present paper presents a two-dimensional numerical study about the geometric optimization of an ocean Wave Energy Converter (WEC) into electrical energy that has as operational principal the Oscillating Water Column (OWC). To do so, the Constructal Design fundamentals were employed to vary the degree of freedom H1/L (ratio between height and length of the OWC chamber), while the other degree of freedom H2/l (ration between height and length of chimney) was kept constant. The OWC chamber area (φ1) and the total OWC area (φ2) are also kept fixed, being the problem constraints. In this study was adopted a regular wave with laboratory scale dimensions. The main goal was to optimize the device’s geometry aiming to maximize the absorbed power when it is subjected to a defined wave climate. For the numerical solution it was used the Computational Fluid Dynamic (CFD) commercial code FLUENT®, which is based on the Finite Volume Method (FVM). The multiphasic Volume of Fluid (VOF) model was applied to treat the water-air interaction. The computational domain was represented by an OWC device coupled into a wave tank. Thereby, it was possible to analyze the WEC subjected to regular wave incidence. An optimal geometry was obtained for (H1/L)o=0.84, being this one approximately ten times more efficient then the worst case (H1/L = 0.14), showing the applicability of Constructal Design in this kind of engineering problem.
49
Merhav, N., e D. L. Neuhoff. "Variable-to-fixed length codes provide better large deviations performance than fixed-to-variable length codes". IEEE Transactions on Information Theory 38, n. 1 (1992): 135–40. http://dx.doi.org/10.1109/18.108258.
Testo completo
50
Ziv, J. "Variable-to-fixed length codes are better than fixed-to-variable length codes for Markov sources". IEEE Transactions on Information Theory 36, n. 4 (luglio 1990): 861–63. http://dx.doi.org/10.1109/18.53746.
Testo completo