• Title/Summary/Keyword: Digital Logic

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Evaluation of Low Power and High Speed CMOS Current Comparators

  • Rahman, Labonnah Farzana;Reaz, Mamun Bin Ibne;Marufuzzaman, Mohammad;Mashur, Mujahidun Bin;Badal, Md. Torikul Islam
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.6
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    • pp.317-328
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    • 2016
  • Over the past few decades, CMOS current comparators have been used in a wide range of applications, including analogue circuits, MVL (multiple-valued logic) circuits, and various electronic products. A current comparator is generally used in an ADC (analog-to-digital) converter of sensors and similar devices, and several techniques and approaches have been implemented to design the current comparator to improve performance. To this end, this paper presents a bibliographical survey of recently-published research on different current comparator topologies for low-power and high-speed applications. Moreover, several aspects of the CMOS current comparator are discussed regarding the design implementation, parameters, and performance comparison in terms of the power dissipation and operational speed. This review will serve as a comparative study and reference for researchers working on CMOS current comparators in low-power and high-speed applications.

A Study on the Gradual Differentiation in Parametric Design (패러매트릭 디자인에서의 점진적 조형특성 연구)

  • Kim, Yong-Hak;Ahn, Seong-Mo
    • Korean Institute of Interior Design Journal
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    • v.27 no.2
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    • pp.175-185
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    • 2018
  • The purpose of this study is to analyze the concept of 'Gradual Differentiation' in parametric design in terms of pure model logic and thus describe the distinctive feature from the previous design method. To meet the purpose, it explores external cases like gradual factor identified in natural phenomenon and artworks and define the inherent model principles into "Self-similarity', "Correlation', and 'Temporality' by examining these features in terms of algorithm. Meanwhile, it identified the principle of gradual model representation in parametric design within a single system called 'Attractor System' by applying these three concepts into specific methods of parametric design, and by interpreting the logical structure through the association among 'Attractor', 'Field', and 'Differentiation'. The creative utilization of parameter shows that gradual model process in parametric design does not mean a passive "conversion process" merely replacing natural parameter with algorithm; rather, it refers to an active "generating process" creating new meanings and value. By continuing this process of conceptual understanding and insight, creative perspective and practical ability to interpret parameter can be improved.

A Study on the Speed Control of PMSM for Elevator Drive (엘리베이터구동용 영구자석형 동기전동기의 속도제어에 관한 연구)

  • Yu J.S.;Kim L.H.;Choi G.J.;Yoon K.C.;Jung M.T.;Kim Y.C.;Lee S.S.;Won C.Y.
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.461-466
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    • 2003
  • This paper presents the speed control of the surface-mounted permanent-magnet synchronous motors (SMPMSM) for the elevator drive. The elevator motor needs to be a compact and slim type. Essentially, the proposed scheme uses a vector control algorithm for a speed and torque control. This system is implemented using a high speed 32-bit DSP (TMS320C31-50), a high-integrated logic device FPGA (EPF10K10-Tl144-3) to design compactly and Inexpensively The proposed scheme is verified through digital simulation and experiments for a three-phase 13.3kW SMPMSM as a MRL(MachineRoomless) elevator motor ill the laboratory. Finally, experiment of the test tower was performed with a 48kW PWM converter-inverter system for a high- speed elevator .

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On supporting full-text retrievals in XML query

  • Hong, Dong-Kweon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.7 no.4
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    • pp.274-278
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    • 2007
  • As XML becomes the standard of digital data exchange format we need to manage a lot of XML data effectively. Unlike tables in relational model XML documents are not structural. That makes it difficult to store XML documents as tables in relational model. To solve these problems there have been significant researches in relational database systems. There are two kinds of approaches: 1) One way is to decompose XML documents so that elements of XML match fields of relational tables. 2) The other one stores a whole XML document as a field of relational table. In this paper we adopted the second approach to store XML documents because sometimes it is not easy for us to decompose XML documents and in some cases their element order in documents are very meaningful. We suggest an efficient table schema to store only inverted index as tables to retrieve required data from XML data fields of relational tables and shows SQL translations that correspond to XML full-text retrievals. The functionalities of XML retrieval are based on the W3C XQuery which includes full-text retrievals. In this paper we show the superiority of our method by comparing the performances in terms of a response time and a space to store inverted index. Experiments show our approach uses less space and shows faster response times.

A Study on the Motor Fault Diagnosis using a Digital Protective Relay System (디지털보호계전시스템을 활용한 모터고장진단에 관한 연구)

  • Lee, Sung-Hwan;Kim, Bo-Yeon;Yi, Dong-Young;Jang, Nak-Won
    • Proceedings of the KIEE Conference
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    • 2006.10d
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    • pp.34-36
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    • 2006
  • In this paper, we will treat the diagnosis problem to accurately determine fault types. The judgement of fault types is accomplished by observing the cluster newly formed with faults and clustering the input current waveforms to intrinsically show the conditions with the dignet that is a clustering algorithm. The types of input current waveforms are, however, constrained during normal operation, though it considers the load character. In case of faults. new clusters are generated outside the clusters. which appear during normal operation, because the input current waveforms of the induction motor are generated by the type which is not observed in case of faults. The diagnosis about the types of faults is essential to building a fault tree about the induction motor, and it removes the causes of the faults using a fuzzy logic. We, first, constitute a fault tree, which connects with the parts and the entire system of the induction motor, and investigate fault modes which can be generated from the fault tree and the relationship of the cause and the effect of each part (of the motor). Also, we distinguish the faults of each part by means of inducing the said of fuzzy relation equations encapsulating the relationship of the fault modes and each part.

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Design Challenges and Solutions for Ultra-High-Density Monolithic 3D ICs

  • Panth, Shreepad;Samal, Sandeep;Yu, Yun Seop;Lim, Sung Kyu
    • Journal of information and communication convergence engineering
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    • v.12 no.3
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    • pp.186-192
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    • 2014
  • Monolithic three-dimensional integrated chips (3D ICs) are an emerging technology that offers an integration density that is some orders of magnitude higher than the conventional through-silicon-via (TSV)-based 3D ICs. This is due to a sequential integration process that enables extremely small monolithic inter-tier vias (MIVs). For a monolithic 3D memory, we first explore the static random-access memory (SRAM) design. Next, for digital logic, we explore several design styles. The first is transistor-level, which is a design style unique to monolithic 3D ICs that are enabled by the ultra-high-density of MIVs. We also explore gate-level and block-level design styles, which are available for TSV-based 3D ICs. For each of these design styles, we present techniques to obtain the graphic database system (GDS) layouts, and perform a signoff-quality performance and power analysis. We also discuss various challenges facing monolithic 3D ICs, such as achieving 50% footprint reduction over two-dimensional (2D) ICs, routing congestion, power delivery network design, and thermal issues. Finally, we present design techniques to overcome these challenges.

Ground station Baseband Controller(GBC) Development of STSAT-2 (과학기술위성2호 관제를 위한 Ground station Baseband Controller(GBC) 개발)

  • Oh Dae-Soo;Oh Seung-Han;Park Hong-Young;Kim Kyung-Hee;Cha Won-Ho;Lim Chul-Woo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.8
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    • pp.482-485
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    • 2005
  • STSAT-2 is first satellite which is scheduled to launch by first Korea launcher. Ground station Baseband Controller(GBC) for operating STSAT-2 is now developing. GBC control data flow path between satellite operation computers and ground station antennas and count number of received data packets among demodulated audio signals from three antennas and also set data flow path to good-receiving antenna automatically In GBC two uplink FSK modulators(1.2kbps, 9.6kbps) and six downlink FSK demodulators(9.6kbps, 38.4kbps) are embedded. STSAT-2 GBC hardware is more simpler than STSAT-1 GBC by using FPGA in which all digital logic implemented. Now test and debugging of GBC hardware and Software(FPGA Code and CBC Manager Program) is well progressing in SaTReC, KAIST. This paper introduce GBC structure, functions and test results.

Control of Boost Converter based on FPGA for Solar Energy System (태양광 발전용 FPGA기반 승압형 컨버터의 제어)

  • Lee Woo-Hee;Kim Hyung-Jin;Chun Kyung-Min;Lee Jun-Ha;Lee Hoong-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.3
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    • pp.512-517
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    • 2006
  • In this study, we designed a digital fuzzy logic controller based on FPGA for MPPT of the solar power generation system. A fuzzy algorithm to control the power tracking function of a boost converter has been built into the FPGA, and applied to the small scaled solar power generation system. The embodied controller showed a stable operation characteristic with the small output voltage ripple for the intensity change of solar radiation. This result proves that the implementation of the power tracking controller using FPGA is an effective way compared to the existing one using microprocessors.

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A Wide Speed Operation of SRM Using Low Cost Encoder and Controller

  • Lee, young-Jin;Prak, Sung-Jun;Park, Han-Woong;Lee, Man-Hyung
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.1
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    • pp.33-42
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    • 2001
  • In switched reluctance motor(SRM) deives, the turn-on and turn-off angles of each phase switch should be accurately controlled for accuracy and efficiency. The accuracy of the switching angles is mainly dependent upon the resolution of the encoder and the sampling period of the microprocessor, that are used to provide the information of the rotor position and to implement a control algorithm of the SRM, respectively. Thus, the higher the speed of the SRM is increased, the larger the amount of the switching angle deviations are from preset turn-on and turn-off angles. Consequently, the motor can not be driven stably high speed region. There fore, a simples and low cost encoder suitable for the practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using a simple digital logic circuit is also presented for a wide speed range operation.

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Real Time 1/3 Octave Band Control System for High Intensity Acoustic Chamber (음향 챔버 내부의 1/3 옥타브 스펙트럼 실시간 제어 시스템)

  • Kim, Young-Key;Kim, Hong-Bae;Moon, Sang-Mu;Woo, Sung-Hyun;Lee, Sang-Seol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.881-885
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    • 2002
  • This paper presents the performance and the algorithm of a 1/3-octave band spectrum control system. The system is developed to provide various spectrums in a high intensity acoustic chamber. The required spectrum, which usually comes from launch vehicle company, starts from 25Hz band and ends 10kHz band. Automatic spectrum control system is preferred since the system requires short settling time to guarantee the safety of test objects and to reduce the amount of operating gas. The developed system adapted a PCI data-acquisition/signal-generation board installed in a personal computer to implement whole control logic. The control software used three cascade digital Butterworth filters using software. The filers are designed following ANSI S1.11 standard to implement 1/3 octave band filter bank. The graphical user interface of the system guides the user to follow standard operation procedure. The averaged control spectrum showed less than 0.05 dB in every running 1/3-octave band.

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