• Title/Summary/Keyword: Fundamental performance

Search Result 1,782, Processing Time 0.03 seconds

Informative Gene Selection Method in Tumor Classification

  • Lee, Hyosoo;Park, Jong Hoon
    • Genomics & Informatics
    • /
    • v.2 no.1
    • /
    • pp.19-29
    • /
    • 2004
  • Gene expression profiles may offer more information than morphology and provide an alternative to morphology- based tumor classification systems. Informative gene selection is finding gene subsets that are able to discriminate between tumor types, and may have clear biological interpretation. Gene selection is a fundamental issue in gene expression based tumor classification. In this report, techniques for selecting informative genes are illustrated and supervised shaving introduced as a gene selection method in the place of a clustering algorithm. The supervised shaving method showed good performance in gene selection and classification, even though it is a clustering algorithm. Almost selected genes are related to leukemia disease. The expression profiles of 3051 genes were analyzed in 27 acute lymphoblastic leukemia and 11 myeloid leukemia samples. Through these examples, the supervised shaving method has been shown to produce biologically significant genes of more than $94\%$ accuracy of classification. In this report, SVM has also been shown to be a practicable method for gene expression-based classification.

Performance Analysis of Carbon Canister for Reducing Evaporative Emissions in a Gasoline Automotive Engine

  • Chung, Yon-Jong;Cho, Gyu-Sang;Erickson, Paul A.;Han, Sung-Bin
    • Journal of Energy Engineering
    • /
    • v.17 no.2
    • /
    • pp.47-53
    • /
    • 2008
  • The objective of this paper is to clarify the flow characteristic, velocity distribution, pressure loss, and other such fundamental data for the canister during loading and purging. The amount of gas that is loaded increases as the loading rate is decreased and the time increased, and the purging improves as the purge rate is increased. The hydrocarbons that are purged initially have a high concentration, and a large amount is purged. During loading and purging, the temperature initially increases and decreases drastically due to heat generation and heat loss.

Comparative Study of Various Persian Stemmers in the Field of Information Retrieval

  • Moghadam, Fatemeh Momenipour;Keyvanpour, MohammadReza
    • Journal of Information Processing Systems
    • /
    • v.11 no.3
    • /
    • pp.450-464
    • /
    • 2015
  • In linguistics, stemming is the operation of reducing words to their more general form, which is called the 'stem'. Stemming is an important step in information retrieval systems, natural language processing, and text mining. Information retrieval systems are evaluated by metrics like precision and recall and the fundamental superiority of an information retrieval system over another one is measured by them. Stemmers decrease the indexed file, increase the speed of information retrieval systems, and improve the performance of these systems by boosting precision and recall. There are few Persian stemmers and most of them work based on morphological rules. In this paper we carefully study Persian stemmers, which are classified into three main classes: structural stemmers, lookup table stemmers, and statistical stemmers. We describe the algorithms of each class carefully and present the weaknesses and strengths of each Persian stemmer. We also propose some metrics to compare and evaluate each stemmer by them.

Analysis of an Interleaved Resonant Converter for High Voltage and High Current Applications

  • Lin, Bor-Ren;Chen, Chih-Chieh
    • Journal of Electrical Engineering and Technology
    • /
    • v.9 no.5
    • /
    • pp.1632-1642
    • /
    • 2014
  • This paper presents an interleaved resonant converter to reduce the voltage stress of power MOSFETs and achieve high circuit efficiency. Two half-bridge converters are connected in series at high voltage side to limit MOSFETs at $V_{in}/2$ voltage stress. Flying capacitor is used between two series half-bridge converters to balance two input capacitor voltages in each switching cycle. Variable switching frequency scheme is used to control the output voltage. The resonant circuit is operated at the inductive load. Thus, the input current of the resonant circuit is lagging to the fundamental input voltage. Power MOSFETs can be turn on under zero voltage switching. Two resonant circuits are connected in parallel to reduce the current stress of transformer windings and rectifier diodes at low voltage side. Interleaved pulse-width modulation is adopted to decrease the output ripple current. Finally, experiments are presented to demonstrate the performance of the proposed converter.

A Study on System Development for Ship's Integrated Safety and Security

  • Yoon, Daeg-Wun;Kim, Cheol-Seung
    • Journal of Navigation and Port Research
    • /
    • v.35 no.2
    • /
    • pp.131-136
    • /
    • 2011
  • As the faithful performance of ISPS of IMO, nowadays actually applicable an integrated safety and security system in and out of vessel should be organized in views of seafarers. Therefore, this paper is aimed to design a fundamental system for ship's integrated safety and security. The system of integrated grabbing will affect efficiently in any maritime field of material and human flow. Therefore this research will be expected to affect economical side by securing all the risk of maritime issues. In addition to the passenger ship and merchant vessel, it is applicable to other public and private vessels either. As a result of this paper, the system designed collecting various data through integrating the system including RFID reader, PIR sensor, and CMOS camera by putting an individual number into each unit that could be control at easy.

Analysis of Importance of Search Altitude Control for Rapid Target Detection of Drones

  • Ha, Il-Kyu
    • Journal of information and communication convergence engineering
    • /
    • v.16 no.2
    • /
    • pp.78-83
    • /
    • 2018
  • Rapidity and accuracy are important considerations when a drone is employed in a wide surveillance area to detect a target. They are more important when the scope of application is a search and rescue operation or the monitoring of natural disasters, which may require prompt warnings and response. During the actual operation of a drone, rapidity and accuracy are associated with the change in the altitude of the drone. The aim of this study is to analyze the characteristics of drones at varying altitudes and prove that altitude is a relevant factor in the performance of drones. Herein, the characteristics of the drone at varying altitudes were analyzed through several search simulations. The results suggest that a high-altitude drone is relatively advantageous compared to a low-altitude drone in a probability-based target search, and that the search altitude is also a very important and fundamental factor in target search by drones.

Control of Grid-Connected Inverters Using Adaptive Repetitive and Proportional Resonant Schemes

  • Abusara, Mohammad A.;Sharkh, Suleiman M.;Zanchetta, Pericle
    • Journal of Power Electronics
    • /
    • v.15 no.2
    • /
    • pp.518-529
    • /
    • 2015
  • Repetitive and proportional-resonant controllers can effectively reject grid harmonics in grid-connected inverters because of their high gains at the fundamental frequency and the corresponding harmonics. However, the performances of these controllers can seriously deteriorate if the grid frequency deviates from its nominal value. Non-ideal proportional-resonant controllers provide better immunity to variations in grid frequency by widening resonant peaks at the expense of reducing the gains of the peaks, which reduces the effectiveness of the controller. This paper proposes a repetitive control scheme for grid-connected inverters that can track changes in grid frequencies and keep resonant peaks lined up with grid frequency harmonics. The proposed controller is implemented using a digital signal processor. Simulation and practical results are presented to demonstrate the controller capabilities. Results show that the performance of the proposed controller is superior to that of a proportional-resonant controller.

Analysis and Implementation of Multiphase Multilevel Hybrid Single Carrier Sinusoidal Modulation

  • Govindaraju, C.;Baskaran, K.
    • Journal of Power Electronics
    • /
    • v.10 no.4
    • /
    • pp.365-373
    • /
    • 2010
  • This paper proposes a hybrid single carrier sinusoidal modulation suitable for multiphase multilevel inverters. Multiphase multilevel inverters are controlled by hybrid modulation to provide multiphase variable voltage and a variable frequency supply. The proposed modulation combines the benefits of fundamental frequency modulation and single carrier sinusoidal modulation (SC-SPWM) strategies. The main characteristics of hybrid modulation are a reduction in switching losses and improved harmonic performance. The proposed algorithm can be applied to cascaded multilevel inverter topologies. It has low computational complexity and it is suitable for hardware implementations. SC-SPWM and its base modulation design are implemented on a TMS320F2407 digital signal processor (DSP). A Complex Programmable Logic Device realizes the hybrid PWM algorithm and it is integrated with a DSP processor for hybrid SC-SPWM generation. The feasibility of this hybrid modulation is verified by spectral analysis, power loss analysis, simulation and experimental results.

New Control Strategy for Conventional VSI in Islanded Microgrid to Enhance Voltage Quality under Nonlinear Loads

  • Dam, Duy-Hung;Lee, Hong-Hee
    • Proceedings of the KIPE Conference
    • /
    • 2015.07a
    • /
    • pp.351-352
    • /
    • 2015
  • This paper proposed a new control strategy for voltage source inverter (VSI) of effective fifth and seventh harmonic reduction in the point of common coupling (PCC) in islanded microgrid under nonlinear load without any additional hardware devices. The non-linear load regularly causes such harmonic distortion, which harmfully affect the performance of other loads or other distributed generation (DG) sources connect to the PCC. In order to improve the quality of delivered output voltage, these harmonic must be rejected. The proposed control strategy is developed based on the current controller formed by resonant controller parallel with a proportional integral controller, which perform on the fundamental reference frame. The reference current is estimated based on the voltage harmonic and the injecting power. The simulation and experimental results are shown to verify the effectiveness of proposed control method.

  • PDF

Power Quality Disturbances Detection Technique using Filter Bank and Adaptive Filters (필터뱅크와 적응필터를 이용한 전력품질 외란 검출기법)

  • Yun, Jae-Jun;Lee, Jeong-Kyu;Sohn, Sang-Wook;Bae, Hyeon-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.1
    • /
    • pp.162-167
    • /
    • 2012
  • In power quality monitoring, it is very important to detect disturbances (sag, swell, transient, and interruption) accurately. In this paper, a detection method for power quality disturbances by combining the filter bank system and adaptive filter is proposed. To decompose power signal, binary tree structured filter bank system is designed. In the filter bank system, the fundamental filter bank(QMF bank) is used as a module in each decomposing level. An adaptive filter is used to improve the detection accuracy of disturbances for each subband signal. In the adaptive filter, the measure of estimated error change is used to detect singular points of power quality disturbances. Computer simulations were performed on synthetic signals which have disturbances to assess the performance of the proposed method.