• Title/Summary/Keyword: Power Constraint

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Design Optimization of CML-Based High-Speed Digital Circuits (전류모드 논리 회로 기반의 고속 디지털 회로 디자인 최적화)

  • Jang, Ikchan;Kim, Jintae;Kim, SoYoung
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.11
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    • pp.57-65
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    • 2014
  • This paper presents a framework that is based on a reconfigurable macro-model of current-mode logic (CML) high-speed digital circuits enabling equation-based design optimization. The proposed macro-model is compatible with geometric programming, thereby enabling constraint-driven top-level power optimization. The proposed optimization framework is applied to a design of CML based serial-link transmitter with user-defined design specifications as an example of high speed digital circuits using 45nm and 90nm CMOS technology. The proposed optimization framework can derive a design with optimal power efficiency for given transistor technology nodes.

Performance Analysis of FEC for Low Power Wireless Sensor Networks (저전력 무선 센서 네트워크를 위한 FEC 성능 분석)

  • Lee, Min-Goo;Park, Yong-Guk;Jung, Kyung-Kwon;Yoo, Jun-Jae;Sung, Ha-Gyeong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.05a
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    • pp.882-885
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    • 2010
  • In view of the severe energy constraint in sensor networks, it is important to use the error control scheme of the energy efficiently. In this paper, we presented FEC (Forward Error Correcting) codes in terms of their power consumption. One method of FEC is RS (Reed-Solomon) coding, which uses block codes. RS codes work by adding extra redundancy to the data. The encoded data can be stored or transmitted. It could have errors introduced, when the encoded data is recovered. The added redundancy allows a decoder to detect which parts of the received data is corrupted, and corrects them. The number of errors which are able to be corrected by RS code can determine by added redundancy. We could predict the lifetime of RS codes which transmitted at 32 byte a 1 minutes. RS(15, 13), RS(31, 27), RS(63, 57), RS(127,115), and RS(255,239) can keep the days of 138, 132, 126, 111, and 103 respectively.

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Three-dimensional anisotropic inversion of resistivity tomography data in an abandoned mine area (폐광지역에서의 3차원 이방성 전기비저항 토모그래피 영상화)

  • Yi, Myeong-Jong;Kim, Jung-Ho;Son, Jeong-Sul
    • Geophysics and Geophysical Exploration
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    • v.14 no.1
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    • pp.7-17
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    • 2011
  • We have developed an inversion code for three-dimensional (3D) resistivity tomography including the anisotropy effect. The algorithm is based on the finite element approximations for the forward modelling and Active Constraint Balancing method is adopted to enhance the resolving power of the smoothness constraint least-squares inversion. Using numerical experiments, we have shown that anisotropic inversion is viable to get an accurate image of the subsurface when the subsurface shows strong electrical anisotropy. Moreover, anisotropy can be used as additional information in the interpretation of subsurface. This algorithm was also applied to the field dataset acquired in the abandoned old mine area, where a high-rise apartment block has been built up over a mining tunnel. The main purpose of the investigation was to evaluate the safety analysis of the building due to old mining activities. Strong electrical anisotropy has been observed and it was proven to be caused by geological setting of the site. To handle the anisotropy problem, field data were inverted by a 3D anisotropic tomography algorithm and we could obtain 3D subsurface images, which matches well with geology mapping observations. The inversion results have been used to provide the subsurface model for the safety analysis in rock engineering and we could assure the residents that the apartment has no problem in its safety after the completion of investigation works.

Three-dimensional Imaging of Subsurface Structures by Resistivity Tomography (전기비저항 토모그래피에 의한 지하구조의 3차원 영상화)

  • Yi Myeong-Jong;Kim Jung-Ho;Chung Seung-Hwan;Suh Jung Hee
    • Geophysics and Geophysical Exploration
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    • v.5 no.4
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    • pp.236-249
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    • 2002
  • We have extended the three-dimensional (3-D) resistivity imaging algorithm to cover the 3-D resistivity tomography problem, where resistivity data are acquired using electrodes installed in several boreholes as well as at the earth surface. The imaging algorithm consists of the 3-D finite element forward modeling and least-squares inversion scheme, where the ACB (Active Constraint Balancing) is adopted to enhance the resolving power of the inversion. Sensitivity analysis with numerical verifications shows that 3-D resistivity tomography is a very appealing method and can be used to get 3-D attitude of subsurface structures with very high-resolution. Moreover, we could accurately handle the topography effect, which could cause artifacts in the resistivity tomography. In the application of 3-D resistivity tomography to the real field data set acquired at the quarry mine, we could derive a very reasonable and accurate image of the subsurface.

Performance Analysis of RS codes for Low Power Wireless Sensor Networks (저전력 무선 센서 네트워크를 위한 RS 코드의 성능 분석)

  • Jung, Kyung-Kwon;Choi, Woo-Seung
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.4
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    • pp.83-90
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    • 2010
  • In wireless sensor networks, the data transmitted from the sensor nodes are susceptible to corruption by errors which caused of noisy channels and other factors. In view of the severe energy constraint in Sensor Networks, it is important to use the error control scheme of the energy efficiently. In this paper, we presented RS (Reed-Solomon) codes in terms of their BER performance and power consumption. RS codes work by adding extra redundancy to the data. The encoded data can be stored or transmitted. It could have errors introduced, when the encoded data is recovered. The added redundancy allows a decoder to detect which parts of the received data is corrupted, and corrects them. The number of errors which are able to be corrected by RS code can determine by added redundancy. The results of experiment validate the performance of proposed method to provide high degree of reliability in low-power communication. We could predict the lifetime of RS codes which transmitted at 32 byte a 1 minutes. RS(15, 13), RS(31, 27), RS(63, 57), RS(127,115), and RS(255,239) can keep the days of 173.7, 169.1, 163.9, 150.7, and 149.7 respectively. The evaluation based on packet reception ratio (PRR) indicates that the RS(255,239) extends a sensor node's communication range by up about 3 miters.

Joint Tx-Rx Optimization in Additive Cyclostationary Noise with Zero Forcing Criterion (가산성 주기정상성 잡음이 있을 때 Zero Forcing 기반에서의 송수신단 동시 최적화)

  • Yun, Yeo-Hun;Cho, Joon-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.7A
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    • pp.724-729
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    • 2007
  • In this paper, we consider a joint optimization of transmitter and receiver in additive cyclostationary noise with zero forcing criterion. We assume that the period of the cyclostationary noise is the same as the inverse of the symbol transmission rate and that the noise has a positive-definite autocorrelation function. The data sequence is modeled as a wide-sense stationary colored random process and the channel is modeled as a linear time-invariant system with a frequency selective impulse response. Under these assumptions and a constraint on the average power of the transmitted signal, we derive the optimum transmitter and receiver waveforms that jointly minimizes the mean square error with no intersymbol interference. The simulation results show that the proposed system has a better BER performance than the systems with receiver only optimization and the systems with no transmitter and receiver optimization.

Efficient Energy Management for a Solar Energy Harvesting Sensor System (태양 에너지 기반 센서 시스템을 위한 효율적인 에너지 관리 기법)

  • Noh, Dong-Kun;Yoon, Ik-Joon
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.7
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    • pp.478-488
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    • 2009
  • Using solar power in wireless sensor networks (WSNs) requires adaptation to a highly varying energy supply and to a battery constraint. From an application's perspective, however, it is often preferred to operate at a constant quality level as opposed to changing application behavior frequently. Reconciling the varying supply with the fixed demand requires good tools for allocating energy such that average of energy supply is computed and demand is fixed accordingly. In this paper, we propose a probabilistic observation-based model for harvested solar energy. Based on this model, we develop a time-slot-based energy allocation scheme to use the periodically harvested solar energy optimally, while minimizing the variance in energy allocation. We also implement the testbed and demonstrate the efficiency of the approach by using it.

Topology Optimization of Offshore Wind-Power Turbine Substructure Using 3D Solid-Element Model (3 차원 고체요소모델을 활용한 해상풍력터빈 하부구조의 위상최적화)

  • Kim, Won Cheol;Chung, Tae Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.309-314
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    • 2014
  • The structural layout of mechanical and civil structures is commonly obtained using conventional methods. For example, the shape of structures such as electric transmission towers and offshore substructures can be generated systematically. However, with rapid advancements in computer graphic technology, advanced structural analyses and optimum design technologies have been implemented. In this study, the structural shape of a jacket substructure for an offshore wind turbine is investigated using a topology optimization technique. The structure is subjected to multiple loads that are intended to simulate the loading conditions during actual operation. The optimization objective function is defined as one that ensures compliance of the structure under the given boundary conditions. Optimization is carried out with constraints on the natural frequency in addition to the volume constraint. The result of a first step model provides quick insights into the optimum layout for the second step structure. Subsequently, a 3D model in the form of the frustum of a quadrilateral pyramid is developed through topology optimization.

Reliability Improvement of the Industrial Equipment Control and Management System Using ZigBee Wireless Network Technology (ZigBee 무선 네트워크 기술을 이용한 산업용 장비 제어 및 관리 시스템의 신뢰성 향상)

  • Kim, Woo-Jin;Kang, Chul-Gyu;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.13 no.5
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    • pp.742-748
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    • 2009
  • Zigbee wireless communication technology has features which are low cost, low power and coping ability against a high delay time when the automatic wireless system is manufactured. Therefore, in this paper, we research a method improving the data transmission reliability of the industrial equipment control and management system using zigbee wireless communication technology. we used a convolutional code with code rate R=1/2, constraint K=5 and generation polynomial constant g1=(10111) and g2=(10011) as a reliability method. From the transmission simulation at LOS environment, we are able to predict the transmission error performance according to the distance difference. Furthermore, At the PER performance analysis, we can get the result that this system reliability with convolutional code is improved about 5 times than the existing system. From these results, we can prove that the convolutional code is the solution to improve the system reliability of the industrial equipment control and management system using zigbee wireless communication technology.

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Construction of Wireless Sensor Network for Intelligent Home (지능형 홈을 위한 무선 센서 네트워크 구성)

  • Whang Se-Hee;Jang In-Hun;Sim Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.15 no.6
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    • pp.695-700
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    • 2005
  • In the sensor network, a lot of sensor nodes are scattered sparsely and organizes a united communication network between each node. After that, environmental information around each sensor node are gathered and analyzed. Because each node operates under resource constraint, the efficiency and hardware specification of a node should be maximized. There exist technical constraints until now but recent technical progress in IC fabrication and wireless network enables to construct a tiny embedded system, which has the properties of low cost, low power consumption, multi functions. Wireless sensor network becomes a modern research field with technical improvements, is studied in numerous laboratories, and is called as diverse different project names - Wireless Integrated Network Sensors (WINS), Mobile Ad hoc NETwork (MANET), Ubiquitous Sensor Network (USN). TinyOS is one of leading project and is widely used. In this paper, we suggest a sensor network, which uses TinyOS platforms and aims for context awareness in a home environment.