WSEAS Transactions on Systems
Contents:
2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | Pre-2008
Print ISSN: 1109-2777
E-ISSN: 2224-2678
Volume 15, 2016
Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.
Volume 15, 2016
Title of the Paper: A Structural Approach to Model Following by Output Feedback in Hybrid Linear Systems with State Jumps
Authors: Elena Zattoni
Abstract: The topic of this work is model following by output feedback in hybrid linear systems with state jumps. In particular, the hybrid linear systems addressed are allowed to exhibit a direct algebraic link from the control input to the regulated output — henceforth referred to as the control feedthrough. Moreover, this study considers the problem of model following from a structural point of view in the sense that it is focused on achieving that the output of the compensated system perfectly follows that of the model, provided that both the compensated system and the model have zero initial conditions, for all the admissible input signals. A necessary and sufficient condition for the existence of a solution to the problem dealt with is proven.
Keywords: Hybrid systems, Model following, Structural approach
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #20, pp. 188-196
Title of the Paper: Simulation and Control of Biomimetic Underwater Vehicle with Undulating Propulsion
Authors: Piotr Szymak
Abstract: In recent times, we may notice some new designs of underwater vehicles, which imitate living underwater organisms, e.g. a fish. These vehicles are called biomimetic. They are driven by undulating propulsion, imitating wavy motion of fins. In the paper, problem of mathematical modeling of underwater vehicle with undulating propulsion is undertaken. This model can be used, e.g. for initial tuning of control system of new underwater vehicles.
Keywords: mathematical model, underwater vehicle, undulating propulsion
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #19, pp. 180-187
Title of the Paper: An Artificial Intelligence Approach to Individuals’ Age Assessment
Authors: Diana Martins, Victor Alves, Henrique Vicente, José Neves
Abstract: A link between patterns of pelvic growth and human life history is supported by the finding that, cross-culturally, variation in maturation rates of female pelvis are correlated with variation in ages of menarche and first reproduction, i.e., it is well known that the human dimensions of the pelvic bones depend on the gender and vary with the age. Indeed, one feature in which humans appear to be unique is the prolonged growth of the pelvis after the age of sexual maturity. Both the total superoinferior length and mediolateral breadth of the pelvis continues to grow markedly after puberty, and do not reach adult proportions until the late teens years. This continuation of growth is accomplished by relatively late fusion of the separate centers of ossification that form the bones of the pelvis. Hence, in this work we will focus on the development of an intelligent decision support system to predict individual’s age based on a pelvis’ dimensions criteria. Some basic image processing techniques were applied in order to extract the relevant features from pelvic X-rays, being the computational framework built on top of a Logic Programming approach to Knowledge Representation and Reasoning that caters for the handling of incomplete, unknown, or even self-contradictory information, complemented with a Case Base approach to computing.
Keywords: Individuals’ Age Prediction, Pelvis X-ray Images, Logic Programming, Knowledge Representation and Reasoning, Case Based Computing, Decision Support Systems
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #18, pp. 168-179
Title of the Paper: Query By Singing/Humming System Using Segment-Based Melody Matching for Music Retrieval
Authors: Wen-Hsing Lai, Chi-Yong Lee
Abstract: Query By Singing/Humming is a melody recognition system for music retrieval by using a singing or humming query. A segment-based melody matching approach is proposed to solve the problems of puff noise and inconsistent tempo, and to lower the computational complexity of traditional Linear Scaling method in Query By Singing/Humming system. The query and midi in database are separated into several segments by four methods we proposed, namely, “Cross n Semitones”, “Moving Average”, “Composite Moving Average”, and “Combination of Cross n Semitones and Composite Moving Average”. Linear scaling is then applied in each corresponding segment. The top 10 recognition rate of our method can reach 70.6%. In addition, from our examples, it shows that segment-based method can solve the problems of puff noise and inconsistent tempo better than traditional global Linear Scaling. The segment-based methods also reduce the computation complexity by jumping to the possible segment boundary and using the segment ratio as scaling ratio, instead of comparing frame by frame from the very beginning and trying different scaling ratio in traditional Linear Scaling method.
Keywords: Query By Singing/Humming, Music Retrieval, Melody Matching, Segment-Based, Linear scaling, Moving Average
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #17, pp. 157-167
Title of the Paper: The Statistics of the K-μ-g Random Variables
Authors: Dragana Krstić, Mihajlo Stefanovic, Vesad Doljak, Zoran Popovic, Radmila Gerov
Abstract: In this paper, the analysis of the κ-μ-g random variable is presented. The κ-μ-g random variable was obtained from κ-μ random variable whose power follows Gamma distribution. The closed form expressions for probability density function (PDF) and cumulative distribution function (CDF) of κ-μ-g random variable are determined. Then, PDFs of the moment of n-th order of κ-μ-g random variable, maximum, minimum, ratio and product of two κ-μ-g random variables are derived in the closed form. This analysis is important for the modelling of the wireless mobile communication systems in the presence of κ-μ-g short term fading, Gamma shadowing and κ-μ-g cochannel interference.
Keywords: κ-μ-g distribution, random variable, probability density function, maximum, minimum, moments, product, ratio, shadowing, short term fading
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #16, pp. 146-156
Title of the Paper: Study of a Semi Active Electromagnetic Regenerative Suspension
Authors: Cannizzaro L., Virzi’ Mariotti G., Giallanza A., Porretto M., Marannano G.
Abstract: The main objective of this work is the theoretical and numerical study of a device that allows recovering energy from an automobile suspension. In place of the viscous damper, which dissipates the kinetic energy of the vehicle due to rough roads or more marked obstacles, an electromagnetic damper performs the functions of the viscous shock absorber with a recovery of electric energy. The damper has permanent magnets and its working is based on the electromagnetic induction. The used ferromagnetic material is the Supermendur, which has very good ferromagnetic properties, but is expensive and difficult to found, so that the choice of different material is useful to reduce the costs. The mathematical model describes the operation of the damper, restoring the values of the electrical and mechanical magnitudes versus the relative speed between the stem and the stator. Several finite element analyses, conducted in ANSYS Workbench Magnetostatic, confirm both the magnetic field and flux values obtained through the theoretical analysis. A calculation example of the energy recovery is done considering an electric minicar transiting on a bumpy road (IRI=3); the recovered power has a total value of 280W about; at last a comparison with similar devices proves the excellent quality of the design also if the comparison should be done with uniformity of the parameters.
Keywords: Suspension, Regenerative damper, Energy harvesting, Electromagnetic shock absorber, FE analysis
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #15, pp. 134-145
Title of the Paper: Medical Magnetic Resonance Image Denoising by Adjusted Non-Local Means Algorithm
Authors: Stefan Korolija, Eva Tuba, Milan Tuba
Abstract: Medical images represent a very important class of digital imeges because they faciliate significant improvements in diagnostics, which is a cornerstone of any medical treatment. Magnetic resonance images are one of the latest and most powerful ways of looking into the human body and differentiating various tissues and organs. Like any physical system, magnetic resonance imaging is prone to interferences and imperfections which appear in the resulting images as different types of noise. Hence, magnetic resonance images are a very important class of medical images and their enhancement is very significant for the quality of diagnostic process. In this paper we presented an algorithm for improving magnetic resonance images of the brain. We tested our proposed adjusted non-local means filter for removing random noise in the magnetic resonance images of the brain on several standard benchmark images. Several evolution metrics were used to prove the quality of the proposed method.
Keywords: Magnetic resonance images, magnetic resonance noise, non-local means filter, magnetic resonance images denoising
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #14, pp. 121-133
Title of the Paper: Total Harmonic Distortion Optimization of the Line Voltage in Single Source Cascaded Multilevel Converter
Authors: Luis David Pabon, Jorge Luis Diaz Rodriguez, Aldo Pardo Garcia
Abstract: This paper describes the harmonic content optimization process of the line voltage in a three-phase H-bridge cascaded multilevel converter with single source topology and 9 levels per phase voltage and 15 levels per line voltage. For optimization reason it was developed a mathematical expression to calculate the line voltage THD in terms of switching angles at the first quarter of the phase voltage modulation waveform. Then problem becomes purely numerical and it's solved using a genetic algorithm, which allows finding a modulation with a THD value close to zero. In order to verify the simulation results, a multilevel power converter with the mentioned topology was developed and its performance tested, with different types of loads.
Keywords: Multilevel power inverter, multilevel PWM modulation, H-bridges cascaded single source, THD, genetic algorithm, optimization
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #13, pp. 110-120
Title of the Paper: Highly Efficient Ultra-Compact Isolated DC-DC Converter with Fully Integrated Active Clamping H-Bridge and Synchronous Rectifier
Authors: Jan Doutreloigne
Abstract: An isolated forward DC-DC converter with monolithically integrated electronics at both sides of the pulse transformer is presented. It converts a 48V DC input voltage into a 12V DC output voltage at 7A load current with a 90.8% overall power efficiency, employing an 800kHz switching frequency, and it occupies a physical volume of 55mm x 35mm x 10mm only. The primary winding of the planar pulse transformer is driven by a new 4-transistor active clamping H-bridge circuit topology that significantly reduces the voltage requirements for the DMOS power devices, thereby enabling monolithic integration of the primary-side electronics in an 80V 0.35?m junction-isolated smart-power IC technology. The switching signal at the secondary winding of the planar pulse transformer is converted into a stable DC output voltage by means of a new synchronous rectifier circuit topology that employs an additional DC-DC buck converter and drastically reduces the dynamic switching losses in the DMOS power devices, thereby boosting the power efficiency and enabling monolithic integration of the secondary-side electronics in an 80V 0.35?m junction-isolated smart-power IC technology.
Keywords: Active clamping, H-bridge, synchronous rectifier, forward converter, DC-DC converter, isolated converter, integrated circuit, smart-power technology
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #12, pp. 102-109
Title of the Paper: Recent Results on Nonlinear, Optimal Regulation and Tracking: Theory and Applications
Authors: Ahmed Khamis, D. Subbaram Naidu
Abstract: The topic of single or multiple objective, optimal control or design has been a very attractive and desirable feature for many dynamic and static systems such as aerospace, electrical, mechanical and robotics, nuclear and aerospace engineering. In particular, in dynamic optimization of nonlinear systems, recent research interest has been the nonlinear, optimal, feedback control using State-Dependent Riccati Equation (SDRE) arising in regulator and tracking problems. This topic can be thought of as the nonlinear counterpart of the most popular linear, quadratic regulator (LQR) based control design. This paper overviews the recent research results of the authors in the theory of the SDRE for regulation and tracking with applications to many engineering systems under deterministic and stochastic environments. Further, the paper presents some future research directions in the field.
Keywords: Nonlinear control, Optimal control, SDRE
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #11, pp. 94-101
Title of the Paper: A Frequency Domain Approach for Design of Stable Fuzzy Logic Systems with Parallel Distributed Compensation
Authors: Snejana Yordanova
Abstract: Most industrial processes are nonlinear, multivariable, with time delay, variable parameters and model uncertainty, subjected to disturbances. There exist methods that compensate the impact of these plant peculiarities but are developed for linear control systems. Most of them are based on the system frequency response since they give a compact and easy design solution. A novel frequency domain approach is suggested for the design of fuzzy logic nonlinear systems with parallel distributed compensation (PDC) from requirements for global nonlinear system stability, robustness and good performance. It uses modified transfer functions based Takagi-Sugeno-Kang (TSK) plant model and PDC and the merits of the linear control frequency design methods. The modified PDC-TSK system is represented by a number of equivalent linear systems for which equivalent frequency responses are defined and frequency domain design criteria applied to ensure stability, robustness and desired performance specifications. The approach is demonstrated for the design of a PDC for the real time control of the air temperature in a laboratory scale dryer and its effectiveness confirmed in the experiments.
Keywords: Frequency response, Fuzzy logic control system design, Nyquist plot, Parallel distributed compensation, Real time temperature control, Takagi-Sugeno-Kang plant model, Nonlinear system stability
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #10, pp. 85-93
Title of the Paper: A Game-Theoretic Approach for Detection of Overlapping Communities in Dynamic Complex Networks
Authors: Elham Havvaei, Narsingh Deo
Abstract: Complex networks tend to display communities which are groups of nodes cohesively connected among themselves in one group and sparsely connected to the remainder of the network. Detecting such communities is an important computational problem, since it provides an insight into the functionality of networks. Further, investigating community structure in a dynamic network, where the network is subject to change, is even more challenging. This paper presents a game-theoretic technique for detecting community structures in dynamic as well as static complex networks. In our method, each node takes a role of a player that attempts to gain a higher payoff by joining one or more communities or switching between them. The goal of the game is to reveal community structure formed by these players by finding a Nash-equilibrium point among them. The main contribution of this paper involves the development of a computationally feasible algorithm for extracting high quality community structure by deployment of existing novel game-theoretic techniques. We present the experimental results illustrating the effectiveness of the proposed method on both synthetic and real-world networks.
Keywords: Community Structure, Overlapping Community Detection, Modularity, Dynamic Network, Extremal Optimization, Nash Equilibrium
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #9, pp. 73-84
Title of the Paper: An Intelligent Agent Tutor System for Detecting Arabic Children Handwriting Difficulty Based on Immediate Feedback
Authors: Ahmed El-Sawy, Hazem El-Bakry, Mohamed Loey
Abstract: In this paper, an intelligent tutor application is built for Arabic preschool children called Arab Handwritten Children Educator (AHCE). AHCE allows Arab children to do practice at anytime and anywhere. As an intelligent tutor, the AHCE can automatically check the handwriting errors, such as stroke sequence errors, stroke direction error, stroke position error, and extra stroke errors. The AHCE provide a useful feedback to Arab children to correct their mistakes. In this paper, attributed mathematics and agents are used to locate the handwritten errors. The system applies a fuzzy approach to evaluate Arabic children handwriting. Experimental results indicate that the proposed intelligent system successfully detect handwriting strokes errors with immediate feedback.
Keywords: Human-Computer Interaction, Intelligent Mobile Tutoring Systems, Handwriting Difficulty, Improving Classroom Teaching, Interactive Learning Environments, Artificial Mobile System
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #8, pp. 63-72
Title of the Paper: System Reliability, Fault Tolerance and Design Metrics Tradeoffs in the Distributed Minority and Majority Voting Based Redundancy Scheme
Authors: P. Balasubramanian
Abstract: The distributed minority and majority voting based redundancy (DMMR) scheme was recently proposed as an efficient alternative to the conventional N-modular redundancy (NMR) scheme for the physical design of mission/safety-critical circuits and systems. The DMMR scheme enables significant improvements in fault tolerance and design metrics compared to the NMR scheme albeit at the expense of a slight decrease in the system reliability. In this context, this paper studies the system reliability, fault tolerance and design metrics tradeoffs in the DMMR scheme compared to the NMR scheme when the majority logic group of the DMMR scheme is increased in size relative to the minority logic group. Some example DMMR and NMR systems were realized using a 32/28nm CMOS process and compared. The results show that 5-of-M DMMR systems have a similar or better fault tolerance whilst requiring similar or fewer function modules than their counterpart NMR systems and simultaneously achieve optimizations in design metrics. Nevertheless, 3-of-M DMMR systems have the upper hand with respect to fault tolerance and design metrics optimizations than the comparable NMR and 5-of-M DMMR systems. With regard to system reliability, NMR systems are closely followed by 5-of-M DMMR systems which are closely followed by 3-of-M DMMR systems. The verdict is 3-of-M DMMR systems are preferable to implement higher levels of redundancy from a combined system reliability, fault tolerance and design metrics perspective to realize mission/safety-critical circuits and systems.
Keywords: NMR, DMMR, Reliability, Fault tolerance, Figure of Merit, Digital design, ASIC, Standard cells
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #7, pp. 59-62
Title of the Paper: Fast Information Detection in Big Data using Neural Networks and Matrix Decomposition
Authors: Hazem M. El-Bakry
Abstract: In previous work, fast neural networks (FNNs) for information extraction was presented. The operation of these networks relies on performing cross-correlation between the input patterns and the weights of processing elements in the frequency domain. In this paper, a new strategy to accelerate this approach is introduced. Such strategy applies the concept of divide and conquer to reduce the number of calculation steps required by FNNs. The big data matrix is decomposed into smaller sub-matrices. Each generated sub-matrix is processed by using a single FNN implemented in the frequency domain. As a result, the speed up ratio is increased with the size of the input big data matrix. This is in contrast to using only FNNs. Simulation results show that the proposed approach for information detection in big data is faster than the conventional neural networks and FNNs. Moreover, experimental results for big data matrices with different sizes show good performance.
Keywords: Big data, Neural networks, Cross correlation, Frequency domain, Fast information detection
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #6, pp. 49-58
Title of the Paper: Shifting Method for Relay Feedback Identification and Control of Delayed Systems
Authors: Milan Hofreiter
Abstract: The paper deals with identification and control of time delay stable plants. A single relay feedback test and the new method called “shifting method” are used for plant identification. For this purpose an asymmetric relay is used. This approach enables to estimate three points on a plant frequency response for three important frequencies from sustained oscillations obtained by a single relay test without using the FFT algorithm. This technique extends possibilities of relay feedback identification and allows fitting up to five parameters of plant transfer functions. This identification method is used for estimating five parameters of the selected anisochronic model that is very universal and convenient for modelling time delay stable systems. This model is then used for anisochronic controller design. The anisochronic controller is proposed by the Desired Model Method. The shifting method and the anisochronic controller design are demonstrated on one simulation example and on the laboratory apparatus called “Air Aggregate”. These experiments were performed using Matlab/Simulink programing environment. The introduced approach provides an automatic tuning tool for a large class of common control problems.
Keywords: Anisochronic control, estimation parameter, frequency response, relay feedback identification, time delay
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #5, pp. 39-48
Title of the Paper: Methodological Approach to the Substantiation of the Form of Compact Build-Up Development Areas with the Aim of their Renovation
Authors: Sergei I. Matreninskiy, Valeriy Y. Mischenko
Abstract: This paper proposes a methodological approach to the establishment of a rational form of the parts of compact build-up development areas intended for reconstruction in accordance with modern requirements. Modernization of the parts of these areas involves renovation of the entire complex of objects located in these areas and requiring reconstruction. These objects include: residential and public buildings, engineering networks, road infrastructure, parks, squares and others. The basis of substantiation of the form of the parts of urban areas for their reconstruction is the principle of similarity of the indicators of physical and moral depreciation, the number of floors in the residential buildings located in these areas and meant for renovation. This is due to the fact that this principle, on the one hand, realizes one of the main needs of society that is safe and comfortable residential buildings, and on the other hand contributes to typification of constructive and organizational and technological decisions made during the planning of the renovation of residential buildings at the given part of the urban area. The methodological approach includes a combination of the following methods: model representation of compact build-up development areas as a system - city planning formations (CPF); determination of physical and moral depreciation of the CPF and its components; method of generating variants of CPF; method of evaluating the effectiveness of the selected variants; method of selecting rational variants of CPF from the generated ones.
Keywords: methodological approach, form, compact build-up development areas, city planning formation (CPF), renovation, moral depreciation, physical depreciation, expert method, Harrington scale
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #4, pp. 28-38
Title of the Paper: Proposal of a Model Based Fault Identification Neural Technique for more-Electric Aircraft Flight Control EM Actuators
Authors: Matteo Dalla Vedova, Paolo Maggiore, Lorenzo Pace, Simone Romeo
Abstract: There are many different ways to detect incipient failures of electromechanical actuators (EMA) of primary flight command provoked by progressive wear. With the development of a prognostic algorithm it’s possible to identify the precursors of an electromechanical actuator failure, to gain an early alert and so get a proper maintenance and a servomechanism replacement. The present work aims to go beyond prognostic algorithms strictly technology-oriented and based on accurate analysis of the cause and effect relationships because if on one hand they show great effectiveness for some specific applications, instead they mostly fail for different applications and technologies. Through the development of a simulation test bench the authors have demonstrated a robust method to early identify incoming failures and reduce the possibility of false alarms or non-predicted problems. Authors took into account friction, backlash, coil short circuit and rotor static eccentricity failures and defined a model-based fault detection neural technique to assess data gained through Fast Fourier Transform (FFT) analysis of the components under normal stress conditions.
Keywords: Artificial Neural Network (ANN), Electromechanical Actuator (EMA), BLDC Motor Failures, Fault Detection/Identification Algorithm, Prognostics
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #3, pp. 19-27
Title of the Paper: Estimation Results on the Location Error when Using Cable Locator
Authors: Hitoshi Kijima,Tomohiko Hattori
Abstract: A cable locator discovers the location as well as depth of underground pipes, cables and wires. Telecommunications services have been interrupted by cutting off underground telecommunications cables installed inside ducts during road construction. In order to prevent such an accident, it is necessary to identify the location of the cables. The system detecting a burial location of the cables is introduced by measuring the maximum magnetic field distribution on the earth surface generated by signaling current flowing through the cables installed inside the ducts. However, an error occurred in the burial location of the cables, when several ducts (it is called three kinds, a vinyl pipe, a cast iron pipe, and a steel pipe) are installed. Therefore, the magnetic field distributions depending on the duct arrangements were analyzed in order to estimate the errors using finite element method.
Keywords: magnetic field, duct, telecommunication cable, burial location, finite element method
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #2, pp. 11-18
Title of the Paper: A Three-Stage Framework for Clustering Mixed Data
Authors: Shi-Hua Liu, Liang-Zhong Shen, De-Cai Huang
Abstract: A three-stage framework and a simple implemented algorithm for clustering mixed data are proposed. In the framework, the mixed dataset is divided into several subsets according to the different types of attributes, and each subset is clustered using according off-the-shelf algorithms, the results are combined as a new categorical dataset and then be clustered. The final result is the answer for clustering the original mixed dataset. The experimental results show that the proposed framework and the implemented algorithm can be used to cluster the mixed dataset efficiently and it is prior to the k-prototypes.
Keywords: Clustering mixed data, Cluster ensemble, Clustering principle, k-prototypes, kMM algorithm
WSEAS Transactions on Systems, ISSN / E-ISSN: 1109-2777 / 2224-2678, Volume 15, 2016, Art. #1, pp. 1-10