Chen's Algorithm Research Articles

Three-Dimensional Pore Structure Characterization of Bituminous Coal and Its Relationship with Adsorption Capacity.

Bituminous coal reservoirs exhibit pronounced heterogeneity, which significantly impedes the production capacity of coalbed methane. Therefore, obtaining a thorough comprehension of the pore characteristics of bituminous coal reservoirs is essential for understanding the dynamic interaction between gas and coal, as well as ensuring the safety and efficiency of coal mine production. In this study, we conducted a comprehensive analysis of the pore structure and surface roughness of six bituminous coal samples (1.19% < Ro,max < 2.55%) using various atomic force microscopy (AFM) techniques. Firstly, we compared the microscopic morphology obtained through low-pressure nitrogen gas adsorption (LP-N2-GA) and AFM. It was observed that LP-N2-GA provides a comprehensive depiction of various pore structures, whereas AFM only allows the observation of V-shaped and wedge-shaped pores. Subsequently, the pore structure analysis of the coal samples was performed using Threshold and Chen's algorithms at ×200 and ×4000 magnifications. Our findings indicate that Chen's algorithm enables the observation of a greater number of pores compared to the Threshold algorithm. Moreover, the porosity obtained through the 3D algorithm is more accurate and closely aligns with the results from LP-N2-GA analysis. Regarding the effect of magnification, it was found that ×4000 magnification yielded a higher number of pores compared to ×200 magnification. The roughness values (Rq and Ra) obtained at ×200 magnification were 5-14 times greater than those at ×4000 magnification. Interestingly, despite the differences in magnification, the difference in porosity between ×200 and ×4000 was not significant. Furthermore, when comparing the results with the HP-CH4-GA experiment, it was observed that an increase in Ra and Rq values positively influenced gas adsorption, while an increase in Rsk and Rku values had an unfavorable effect on gas adsorption. This suggests that surface roughness plays a crucial role in gas adsorption behavior. Overall, the findings highlight the significant influence of different methods on the evaluation of pore structure. The 3D algorithm and ×4000 magnification provide a more accurate description of the pore structure. Additionally, the variation in 3D surface roughness was found to be related to coal rank and had a notable effect on gas adsorption.

IMPLEMENTASI METODE FUZZY TIME SERIES DENGAN MODEL ALGORITMA CHEN UNTUK MEMPREDIKSI HARGA EMAS

Gold is one of the people's preferred forms of investment and is considered the safest (save -heaven). Gold risk which is considered small is the main attraction because in general Indonesian people are not yet familiar with capital market investments such as stocks and mutual funds. But the price of gold is very volatile as for the factors that affect the fluctuations of gold are consumption demand, volatility and market uncertainty, protection of low-interest rates, and the US dollar. Predicting the movement of the gold price and knowing where the direction of the exchange rate moves and determining the price of gold up or down cannot be done accurately and consistently. For this reason, in reducing the risk of loss, an application is needed to predict gold prices using the Fuzzy Time Series Chen algorithm using MATLAB software. In this study to obtain prediction results and comparison charts using actual data and prediction data for the 2015-2017 gold price. From the calculation results obtained by the prediction results with the Fuzzy Time Series method with the Chen algorithm where the average difference between the actual data and prediction data is not more than Rp. 2,850, - where predictions using the Fuzzy Time Series method Chen's algorithm is sufficient to use 1 data to predict the second data which makes this method accurate in predicting the price of gold.

Finding the Maximal Eigenpair for a Large, Dense, Symmetric Matrix based on Mufa Chen's Algorithm

Finding the Maximal Eigenpair for a Large, Dense, Symmetric Matrix based on Mufa Chen's Algorithm

A New Way to Find the Minimum Distance of BCH and Quadratic Double Circulant Codes

BCH (Bose, Chaudhuri, Hocquenghem) and QDC (Quadratic Double Circulant) codes are important classes of linear codes with many application domains. For large lengths, the true value of the minimum distances of these codes remains undetermined and therefore their error correcting capabilities are still unknown. The problem of searching codewords of lowest weight in linear codes is NP-hard problem and it is equivalent to the problem of the minimum distance research. Many methods have been used to attack this hardness such as genetic algorithms, simulated annealing, Multiple Impulse Method (MIM), Chen algorithm, Canteaut-Chabaud and Zimmermann algorithms. In a previous work, we have presented the method MIM-RSC to find the minimum weights by applying the MIM method on some Random sub codes of reduced dimensions. This reduction allows an efficient local search, but the important question here is which are the sub codes containing the lowest weights and how find them?. In general, the answer of this question isn’t evident and consequently many random sub codes should be exploited to have a great chance for taking a true minimum weight codeword. In this work, we present a new way to catch lowest weights by applying the Zimmermann algorithm on these random sub codes. This proposed scheme, Zimmermann-RSC, is validated on some BCH and QDC codes of known minimum weight and it is used to determine the minimum distance for many other codes of large lengths belonging to these families. The comparison between some competitors methods with the proposed scheme Zimmermann-RSC on many large BCH and QDC codes proves the efficiency of this latest in terms of the results quality and run time.

Fingerprint Image Enhancement Algorithms for Identification in an Electoral Process

Electoral process in many developing nations is characterized with fraud and failure as a result of inefficient and effective system of voter’s register and voting system. This usually leads to crises. This paper presents enhancement algorithms of Denoising fingerprint images using Moving Average Filter, the Segmentation of Fingerprint using Chen algorithm, Gradient-Based Local Ridge Orientation, Binarization using Otsu Algorithm, Thinning of Fingerprint Image using the linear interactive approach and Minutiae Extraction using the minutiae location and minutiae angles for the purpose of verification and Identification in electoral process. The input to the system is a Gray-scale Fingerprint image of electorate and it detailed information while the Output is a Verified and enrolled fingerprint image with matching score and details of electorates’ information store as Template using the Matlab 2013a.

An examination of calibration intervals required for accurately tracking blood pressure using pulse transit time algorithms

Pulse transit time (PTT) is defined as the time it takes the blood pressure (BP) wave to propagate from the heart to a specified point on the body. After an initial BP measurement, PTT can track BP over short periods of time. This paper evaluates two PTT algorithms: Chen's and Poon's algorithm; two of the most cited works in the area. The criteria for evaluating them were: which was capable of best tracking changes in BP and which provided the longest time between subsequent BP measurements. These establish the suitability of the PTT method for practical applications, which has not been examined previously. Accuracy was evaluated using the Association of Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society's (BHS) standards. Results show that Chen's algorithm is dependent on its lookup table at short intervals but remains accurate using a 6-min calibration interval, with r=0.96 and r(2)=0.98. Poon's algorithm fails when using a 2-min calibration interval, but is more capable of reflecting changes in BP. The short calibration interval and accuracy limit the usefulness of calculating BP using PTT. Therefore, neither of the algorithms can be recommended because of their shortcomings when estimating BP.

Efficient Majority-Logic Decoding of Short-Length Reed-Muller Codes at Information Positions

Short-length Reed--Muller codes under majority-logic decoding are of particular importance for efficient hardware implementations in real-time and embedded systems. This paper significantly improves Chen's two-step majority-logic decoding method for binary Reed--Muller codes $\text{RM}(r,m)$, $r \leq m/2$, if --- systematic encoding assumed --- only errors at information positions are to be corrected. Some general results on the minimal number of majority gates are presented that are particularly good for short codes. Specifically, with its importance in applications as a 3-error-correcting, self-dual code, the smallest non-trivial example, $\text{RM}(2,5)$ of dimension 16 and length 32, is investigated in detail. Further, the decoding complexity of our procedure is compared with that of Chen's decoding algorithm for various Reed--Muller codes up to length $2^{10}$.

Optimal and isodual ternary cyclic codes of rate 1/2

This work is twofold. First, the largest minimum distance of a ternary cyclic codes of parameters (n, n 2 ), is determined for n even, not a multiple of 3, by using the Chen algorithm, for n = 26, 34, 38, 46, 50, 58, 62, 68, 70, 74. Next, seven new classes of isodual ternary cyclic codes are introduced for n singly even, not a multiple of 3.

A FPGA implementation of Chen's algorithm

This article is devoted to describing an implementation of Chen's algorithm on FPGA. This algorithm allows the computation of minimum distance of cyclic codes. As an application, we determine the minimum distance of quadratic residue codes of length 223.

On the k-error linear complexity of sequences with period 2p n over GF(q)

In this paper, we first optimize the structure of the Wei---Xiao---Chen algorithm for the linear complexity of sequences over GF(q) with period N = 2p n , where p and q are odd primes, and q is a primitive root modulo p 2. The second, an union cost is proposed, so that an efficient algorithm for computing the k-error linear complexity of a sequence with period 2p n over GF(q) is derived, where p and q are odd primes, and q is a primitive root modulo p 2. The third, we give a validity of the proposed algorithm, and also prove that there exists an error sequence e N , where the Hamming weight of e N is not greater than k, such that the linear complexity of (s + e) N reaches the k-error linear complexity c. We also present a numerical example to illustrate the algorithm. Finally, we present the minimum value k for which the k-error linear complexity is strictly less than the linear complexity.

Optimizing Chew and Chen's Pitch-Spelling Algorithm

Pitch-spelling algorithms attempt to compute the correct pitch names (e.g., C#4, Bb5) of the notes in a passage of tonal music, when given only the onset time, MIDI note number, and possibly the duration and voice of each note. This article reports on a study in which Chew and Chen’s (2003a, 2003b, 2005) pitch-spelling algorithm was re-implemented and then optimized by running it with a range of different parameter value combinations on a test corpus containing 195,972 notes and consisting of 216 movements from works by eight Baroque and Classical composers. The results of this evaluation cast doubt upon some of the claims made by Chew and Chen that were based on results obtained by running their algorithm on a much smaller test corpus containing only 4,462 notes and consisting of just two movements from sonatas by Beethoven and You-Di Huang’s Song of Ali-Shan. The results presented here suggest that Chew and Chen’s algorithm could be simplified in various ways without compromising its performance.

Computer Simulation of Grain Growth in Three Dimensions by the Phase Field Model with Anisotropic Grain-Boundary Mobilities

The kinetics and topology of grain growth in three dimensions were simulated using a phase-field model with anisotropic grain-boundary mobilities. In order to perform large scale calculations we applied both modifications of algorithms and parallel coding techniques to the Fan and Chen's phase-field algorithm. Kinetics of abnormal grain growth is presented. It is observed that the grains of a minor component which are at the beginning surrounded preferentially by boundaries of high mobility grow faster than the grains of a major component until the texture reverses completely. Additionally, topological results of grain structures, such as grain size distributions and grain face distributions, are discussed

On Chen and Chen's new tree inclusion algorithm

Very recently, Chen and Chen [Y. Chen, Y. Chen, A new tree inclusion algorithm, Information Processing Letters 98 (2006) 253–262] gave a new algorithm for the tree inclusion problem, which requires O ( | T | × min { depth ( P ) , | leaves ( P ) | } ) time and no extra space. In this Note, we show that there are flaws in their time-complexity analysis by presenting two counterexamples. We also give an example to show that the worst-case time complexity of their algorithm is non-polynomial. Consequently, the asymptotically most efficient algorithm for the tree inclusion problem is the former algorithm in [W. Chen, More efficient algorithm for ordered tree inclusion, Journal of Algorithms 26 (1998) 370–385].

A simple timeout algorithm for point-to-multipoint ABR service

The ABR point-to-multipoint connection is now playing a more important role than before. Many consolidation algorithms have been proposed to solve the consolidation noise problem and the slow transient response problem. But few timeout algorithms are proposed to handle the non-responsive branches for the multicast connections. Chen's algorithm needs exchanging control messages between switches [9]. Besides, it may mistake a responsive branch as a non-responsive branch because of fast changes in source rates, which causes wrong information in BRM cells and may lead to network congestion and data losses in the responsive branch. We propose a simple timeout algorithm which can handle the non-responsive branches without exchanging message between switches. The timeout value for each switch is computed locally. Simulation results show that the proposed timeout algorithm can efficiently handle the non-responsive branches and utilize the available bandwidth within a small period of time. In addition, our algorithm could handle the situation when the source rates change quickly.

Representing user preference in engineering design domains using an enhanced weighted fuzzy reasoning algorithm

This article addresses a specific feature of the engineering design process, i.e. the assignment of priorities among the parameters that constrain the design process. These parameters are often fuzzy in nature and Chen's weighted fuzzy reasoning algorithm was adapted for reasoning with them. We present the modified version of Chen's algorithm, which is called the enhanced weighted fuzzy reasoning algorithm, and apply it to some sample rules developed for the domain of solvent selection for carbon dioxide removal processes. This article also suggests how the proposed algorithm improves upon previous efforts at automating the solvent selection for the carbon dioxide removal task.

Efficacité des techniques de régénération d'eau pour une usine de fabrication de papier intégrée sans effluent. Analyse exergétique

Water regeneration efficiency for pulp and paper plant. Exergy analysis. The water network of a pulp and paper mill is contaminated by a large number of components which are brought into the system as wood constituants or process additives. Keeping the contaminant concentrations below certain limits, to safeguard paper quality and process runnability, must be part of any systems closure strategy. This can be achieved by purging contaminants using well known separation techniques such as evaporation, freeze crystallization and membrane filtration. The purpose of this study was to compare the thermodynamic efficiency of these techniques by means of an advanced exergy analysis. The contaminated stream was modelled using key components for both organic and inorganic contaminants. The activity coefficients were calculated using the Chen algorithm. The approach developed by Brodyanski, Sorin and Le Goff was used to determine the exergy efficiency. This analysis shows that freeze crystallisation is the most efficient technique when the exergy of the output stream is considered as a useful effect. When only the useful work obtained by separation is considered, membrane separation becomes the most efficient process. The analysis of the process incorporating a separation operation produces the actual efficiency. This example illustrates the advantage of using exergy methods to determine the efficiency of processes based on different physico-chemical phenomena.

Word-level recognition of small sets of hand-written words

A system is presented for off-line word-level recognition of small sets of hand-written words. The system performs well on a variety of tasks such as recognizing numerals hand-written in English (one through ten), Hebrew characters, and Pascal's reserved words. Only small changes are needed in the parameters of the system when switching from one application to another. The heart of the proposed system is the use of dynamic programming for matching between a word in question and a prestored model of a word. The matching algorithm which uses line segments as its input is similar to Lee and Chen's algorithm for matching Chinese characters. We vary the segmentation algorithm showing that regardless of the segmentation algorithm chosen, the average recognition rate usually exceeds 95%. Different thinning algorithms are also shown not to reduce the stated recognition rate and a rejection scheme further enhances it.

Conditions for the equivalence of the Chen and Yee FDTD algorithms

A two-dimensional dispersion analysis of the recently proposed Chen finite-difference time-domain (FDTD) algorithm is presented and its properties evaluated. The dispersion properties of this scheme vary with respect to propagation angle, Courant stability factor, and the definition of numerical characteristic impedance. These dispersion characteristics can be used to identify parameters that make the Chen algorithm equivalent to the Yee FDTD algorithm. >

Fast Sorting Algorithms on Uniform Ladders (Multiple Shift-Register Loops)

This paper presents two sorting algorithms on the uniform ladder (a new storage device based on charged coupled devices, or magnetic bubbles implementation, proposed by Chen et al.). It is assumed that control and comparison timings are negligible when compared to the relatively slow bubble movements. The first algorithm (Algorithm 1) enables the sorting process on a single ladder to be completely embedded in the input/output time (whereas Chen's algorithm (SLISO) has a 20 percent unoverlapped sorting time in the load-sort-unload process). When one ladder cannot accommodate all the input records and two or more ladders are needed, Algorithm 2 attains a negligible unoverlapped sorting time (which can be removed with a minor modification in the system hardware and hence in Algorithm 2). In comparison, Algorithm 2 obviates the need for explicit merging of the ladders, which is required in Chen's algorithm (MLISO). This implies that unlike the MLISO scheme, ladders are not tied up for merging, and can be recycled once their contents are outputted. Therefore, in a real processing environment, the number of ladders required by Algorithm 2 may even be less than the theoretical minimum which can be attained by the MLISO scheme.