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A pathway-based approach for analyzing microarray data using random forests

ICIC Express Letters 2012年第5期6卷 1253-1257页

作者： Shi, Chin Hui Mohamad, Mohd Saberi Deris, Safaai Ibrahim, Zuwairie Articial Intelligence and Bioinformatics Research Group Faculty of Computer Science and Information Systems Malaysia Department of Mechatronics and Robotics Center for Articial Intelligence and Robotics Faculty of Electrical Engineering Universiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia

Although machine learning methods, such as random forests, have been developed to correlate survival outcomes with a set of genes, less study has assessed the abilities of these methods in incorporating pathway information for analyzing microarray data. In general, genes that are identified without incorporating biological knowledge are more difficult to interpret. Thus, the pathway-based survival analysis using machine learning methods represents a promising approach for generating new biological hypothesis from microarray studies. The two popular variants of random forests used in this research for survival data are random survival forests and bivariate node-splitting random survival forests. There are three types of datasets used for this research and each dataset with a three-level outcome. This research which compared the four splitting rules available in random survival forests to identify log-rank test is the most accurate in terms of prediction error. To evaluate the accuracy of pathway based survival approach, this research considered employing area under the receiver operating characteristic curve for censored data. The use of random survival forests for survival outcomes in analyzing microarray data allows researchers to obtain results that are more closely tied with the biological mechanism of diseases.

关键词： Genes

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Autonomous release of a snagged solar array: Technologies and laboratory demonstration

Autonomous release of a snagged solar array: Technologies an...

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AIAA Guidance, Navigation, and control Conference 2012

作者： Glenn Creamer, N. Hartley, Ralph L. Glen Henshaw, C. Roderick, Stephen N. Hope, Jamison R. Obermark, Jerome L. Control Systems Branch Naval Research Laboratory Code 8231 4555 Overlook Avenue Washington DC 20375 United States PTR Group 2325 Dulles Corner Boulevard Herndon VA 20171 United States DCS Corporation 6909 Metro Park Drive Alexandria VA 22310 United States Naval Center for Applied Research in Artificial Intelligence Code 5515 4555 Overlook Avenue United States

ISBN: (纸本)9781600869389

This paper describes a novel concept of operations, payload hardware, terminal navigation strategy, and localized vision scheme for autonomous release of a snagged solar array using a robotic servicing spacecraft. The hardware suite on the servicer consists of two robot arms, end effector cameras, a scanning laser sensor, two local fixed lasers, an end effector fiducial tool, and various active light sources for long-range and localized target illumination. The concept of operations consists of a terminal approach phase, a servicer preparation phase, and an array release phase. The scanning laser sensor is utilized throughout all phases to determine target pose, while the end effector cameras are utilized during the approach phase for variable baseline stereo ranging and during the release phase for localized scene imaging and arm guidance. Realistic full-scale laboratory tests in a six degree-of-freedom relative navigation and control testbed demonstrate the complex integration and interaction of close-range autonomous relative navigation, cooperative dual-arm robotics, and localized machine vision necessary to perform such a task.

关键词： Cameras

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Autonomous aerobraking development software: Phase one performance analysis at Mars, Venus, and Titan

Autonomous aerobraking development software: Phase one perfo...

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AIAA/AAS Astrodynamics Specialist Conference 2012

作者： Maddock, Robert W. Bowes, Angela Powell, Richard W. Prince, Jill L. H. Cianciolo, Alicia Dwyer Atmospheric Flight and Entry Systems Branch NASA Langley Research Center 1 N. Dryden St./MS 489 Hampton VA 23681 United States Guidance Navigation and Control Group Analytical Mechanics Associates Inc. 1 N. Dryden St./MS 489 Hampton VA 23666 United States

ISBN: (数字)9781624101823

ISBN: (纸本)9781624101823

When entering orbit about a planet or moon with an appreciable atmosphere, instead of using only the propulsion system to insert the spacecraft into its desired orbit, aerodynamic drag can be used after the initial orbit insertion to further decelerate the spacecraft. Several past NASA missions have used this aerobraking technique to reduce the fuel required to deliver a spacecraft into a desired orbit. Aerobraking was first demonstrated at Venus with Magellan in 1993 and then was used to achieve the science orbit of three Mars orbiters: Mars Global Surveyor in 1997, Mars Odyssey in 2001, and Mars Reconnaissance Orbiter in 2006. Although aerobraking itself reduces the propellant required to reach a final low period orbit, it does so at the expense of additional mission time to accommodate the aerobraking operations phase (typically 3-6 months), a large mission operations staff, and significant Deep Space Network (DSN) coverage. By automating ground based tasks and analyses associated with aerobraking and moving these onboard the spacecraft, a flight project could save millions of dollars in operations staffing and DSN costs (Ref. 1).

关键词： Aerobraking

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Multivariate analysis of gene expression data and missing value imputation based on llsimpute algorithm

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ICIC Express Letters 2012年第5期6卷 1335-1339页

作者： Moorthy, Kohbalan Mohamad, Mohd Saberi Deris, Safaai Ibrahim, Zuwairie Artificial Intelligence and Bioinformatics Research Group Faculty of Computer Science and Information Systems 81310 UTM Skudai Johor Malaysia Department of Mechatronics and Robotics Center of Artificial Intelligence and Robotics Faculty of Electrical Engineering Universiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia

Microarray ade4 or known as MADE4 is a multivariate software analysis package for microarray gene expression data. This software package is capable of accepting wide variety of gene expression data formats such as Bioconductor Affy Batch and exprSet. This MADE4 R package extends the advantages of ade4 package in multivariate statistical and graphical functions for the use in the microarray data application. Moreover, MADE4 provides new graphical and visualization tools that assist in the interpretation of multivariate analysis of microarray data. Besides that, LLSimpute algorithm has been incorporated to assist in handling of datasets with missing values and this has eased the application for the users to analysis on gene expression data that contain missing values.

关键词： Autocorrelation

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Pointing alignment estimation for precision pointing determination: Modeling, estimation method, and calibration

Pointing alignment estimation for precision pointing determi...

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AIAA Guidance, Navigation, and control Conference 2012

作者： Iwata, Takanori Tadono, Takeo Kawahara, Tetsuo Abe, Masakazu Japan Aerospace Exploration Agency Tsukuba Ibaraki 305-8505 Japan NEC Corporation Fuchu Tokyo 183-8501 Japan CIJ Next Shinjuku Tokyo 162-0825 Japan Guidance and Control Group 2-1-1 Sengen Japan Earth Observation Research Center 2-1-1 Sengen Japan Integrated Systems Department Space Systems Division 1-10 Nisshin-cho Japan GIS Solution Department 4-8 Kagurazaka Japan

ISBN: (数字)9781600869389

ISBN: (纸本)9781600869389

The improved accuracy of attitude sensors has revealed that change and estimation error of pointing alignment became a dominant factor in pointing determination for highresolution Earth observation. The Advanced Land Observing Satellite (ALOS), which was launched on January 24, 2006, introduced a new approach to pixel geolocation determination and enabled fast and uniformly-precise geometric correction without ground control points. In this process, the pointing alignment has been a major source of error and has required continued calibration. This paper proposes modeling and an estimation algorithm for the pointing alignment change. The modeling assumes that the change consists of a bias term, orbit periodic terms, and a long-term drift, and the estimation applies weighted least-square optimization to this model. The paper also reports its operational calibration results based on flight data. © 2012 by Takanori Iwata.

关键词： Alignment

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A tuning parameter selector method for the gsvm-scad in determining significant genes and biological pathway

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ICIC Express Letters 2012年第4期6卷 851-856页

作者： Misman, Muhammad Faiz Mohamad, Mohd Saberi Deris, Safaai Hashim, Siti Zaiton Mohd Leham, Nurdyana Ibrahim, Zuwairie Artificial Intelligence and Bioinformatics Research Group Faculty of Computer Science and Information Systems 81310 UTM Skudai Johor Darul Takzim Malaysia Department of Mechatronics and Robotics Center for Artificial Intelligence and Robotics Faculty of Electrical Engineering Universiti Teknologi Malaysia 81310 UTM Skudai Johor Darul Takzim Malaysia

A hybrid of support vector machines and a smoothly clipped absolute deviation with group-specific penalty terms (gSVM-SCAD) is a penalized classifier that has been used to identify and select significant pathways in pathway-based microarray analysis. Despite its advantages in identifying significant pathways, the gSVM-SCAD has some limitations, as it depends on the proper choice of tuning parameter. If the tuning parameter is too small, it can bring little sparsity and overfit to the classifier model, while if it is too large, it can make much sparsity to the classifier model and produce poor discriminating power. Therefore, it is important to choose an appropriate tuning parameter selector method for the gSVM-SCAD. The generalized cross validation (GACV) has been widely used as a tuning parameter selector method. Unfortunately, GACV has some limitations where it poorly performs when dealing with the low number of variables (in this paper referred as genes) and large sample sizes. This is because some pathways contain not more than 100 genes and even some pathways contain less than 10 genes. This scenario can lead to the poor performance of SCAD in selecting the informative genes and simultaneously identifying significant ones. In order to surmount the limitations of the gSVM-SCAD, we proposed to use the B-type generalized approximate cross validation (BGACV) as a tuning parameter selector method for gSVM-SCAD. ICIC International © 2012.

关键词： Genes

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Simulation-based optimum sensor selection design for an uncertain EMS system via Monte-Carlo technique

Simulation-based optimum sensor selection design for an unce...

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作者： Michail, Konstantinos Zolotas, Argyrios C. Goodall, Roger M. Energy Environment and Water Research Center Cyprus Institute Nicosia Cyprus Control Systems Group Department of Electronic and Electrical Engineering Loughborough University Loughborough United Kingdom

ISBN: (纸本)9783902661937

Optimum sensor selection in control system design is often a non-trivial task to do. This paper presents a systematic design framework for selecting the sensors in an optimum manner that simultaneously satisfies complex system performance requirements such as optimum performance and robustness to structured uncertainties. The framework combines modern control design methods, Monte Carlo techniques and genetic algorithms. Without losing generality its efficacy is tested on an electromagnetic suspension system via appropriate realistic simulations. © 2011 IFAC.

关键词： Genetic algorithms

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Optimal selection for sensor fault tolerant control of an EMS system via loop-shaping robust control

Optimal selection for sensor fault tolerant control of an EM...

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Mediterranean Conference on control and Automation

作者： Michail, Konstantinos Zolotas, Argyrios C Goodall, Roger M Halikias, George Energy Environment and Water Research Center Cyprus Institute Nicosia Cyprus Control Systems Group Department of Electronic and Electrical Engineering Loughborough University Loughborough United Kingdom Control Engineering Research Centre School of Engineering and Mathematical Sciences City University London United Kingdom

ISBN: (纸本)9781457701252

A systematic framework is presented for optimum sensor selection for control and fault tolerance subject to complex system requirements. The framework combines the well known robust control via loop-shaping design, the fault tolerance control concept and multiobjective optimisation. The framework is tested via realistic simulations on an Electro-Magnetic Suspension system which is a non-linear, unstable and safety-critical system with a set of non-trivial requirements. © 2011 IEEE.

关键词： Robust control

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Steering force feedback for humanmachine-interface automotive experiments

Steering force feedback for humanmachine-interface automotiv...

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作者： Katzourakis, Diomidis I. Abbink, David A. Happee, Riender Holweg, Edward Biomechanical Engineering and the Intelligent Automotive Systems Research Groups Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology 2628 CD Delft Netherlands Biomechanical Engineering Research Group Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology 2628 CD Delft Netherlands Delft Center for Systems and Control and the Intelligent Automotive Systems Research Group Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology 2628 Delft Netherlands Automotive Development Center Svenska Kullagerfabriken 3430 DT Nieuwegein Netherlands

Driving-simulator fidelity is usually defined by the quality of its visual and motion cueing system. However, the quality of its haptic cues is also very important and is determined by both hardware and control properties. Most experiments with haptic steering systems employ commercially available systems and do not address the system's fidelity. The goal of this paper is to offer guidelines for the development of hardware, performance evaluation, and system control in order to engineer realistic haptic cues on the steering wheel. A relatively low-cost solution for hardware is deployed, consisting of a velocity-controlled three-phase brushless servomotor, of which its high-bandwidth control allows for a realistic representation of forces. A method is presented to overcome electromagnetic interference produced by the industrial servomotor and the controller through careful amplification and filtering. To test the system, different inertiaspringdamper systems were simulated and evaluated in time and frequency domain. In conclusion, the designed system allowed reproduction of a large range of steering-wheel dynamics and forces. As a result, the developed system constitutes an efficient haptic device for humanmachine-interface automotive experiments. © 2010 IEEE.

关键词： Signal interference

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Simulation-based Optimum Sensor Selection Design for an Uncertain EMS System via Monte-Carlo Technique.

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IFAC Proceedings Volumes 2011年第1期44卷 12650-12655页

作者： Argyrios C. Zolotas Konstantinos Michail Roger M. Goodall Energy Environment and Water Research Center The Cyprus Institute Nicosia Cyprus Control Systems Group Department of Electronic and Electrical Engineering Loughborough University Loughborough UK

Abstract Optimum sensor selection in control system design is often a non-trivial task to do. This paper presents a systematic design framework for selecting the sensors in an optimum manner that simultaneously satisfies complex system performance requirements such as optimum performance and robustness to structured uncertainties. The framework combines modern control design methods, Monte Carlo techniques and genetic algorithms. Without losing generality its efficacy is tested on an electromagnetic suspension system via appropriate realistic simulations.

关键词： optimum sensor selection modern control design EMS systems Monte Carlo genetic algorithms

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