• Title/Summary/Keyword: Simulation operation

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Optimization of Dispatching Strategies for Stacking Cranes Including Remarshaling Jobs (재정돈을 포함한 장치장 크레인의 작업 할당 전략 최적화)

  • Kim, Taekwang;Yang, Youngjee;Bae, Aekyoung;Ryu, Kwang Ryul
    • Journal of Navigation and Port Research
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    • v.38 no.2
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    • pp.155-162
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    • 2014
  • In container terminals, stacking yard is the place where import and export containers are temporarily stored before being loaded onto or after being discharged from a ship. Since all the containers go through the stacking yard in their logistic flow, the productivity of the terminal critically depends on efficient operation of stacking yard, which again depends on how well the stacking locations of the incoming containers are determined. However, a good location for stacking an incoming container later can turn out to be a bad one when that container is to be fetched out of the stacking yard, especially if some rehandling is required. This means that good locations for the containers are changing over time. Therefore, in most container terminals, the so-called remarshaling is done to move the containers from bad location to good locations. Although there are many previous works on remarshaling, they all assume that the remarshaling can be done separately from the main jobs when the cranes are idle for rather a long period of time. However, in reality, cranes are hardly available for a period long enough for remarshaling. This paper proposes a crane dispatching strategy that allows remarshaling jobs to be mixed together with the main jobs whenever an opportunity is detected. Experimental results by simulation reveals that the proposed method effectively contributes to the improvement of terminal productivity.

Third order Sigma-Delta Modulator with Delayed Feed-forward Path for Low-power Operation (저전력 동작을 위한 지연된 피드-포워드 경로를 갖는 3차 시그마-델타 변조기)

  • Lee, Minwoong;Lee, Jongyeol
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.10
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    • pp.57-63
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    • 2014
  • This paper proposes an architecture of $3^{rd}$ order SDM(Sigma-Delta Modulator) with delayed feed-forward path in order to reduce the power consumption and area. The proposed SDM improve the architecture of conventional $3^{rd}$ order SDM which consists of two integrators. The proposed architecture can increase the coefficient values of first stage doubly by inserting the delayed feed-forward path. Accordingly, compared with the conventional architecture, the capacitor value($C_I$) of first integrator is reduced by half. Thus, because the load capacitance of first integrator became the half of original value, the output current of first op-amp is reduced as 51% and the capacitance area of first integrator is reduced as 48%. Therefore, the proposed method can optimize the power and the area. The proposed architecture in this paper is simulated under conditions which are supply voltage of 1.8V, input signal 1Vpp/1KHz, signal bandwidth of 24KHz and sampling frequency of 2.8224MHz in the 0.18um CMOS process. The simulation results are SNR(Signal to Noise Ratio) of 88.9dB and ENOB(Effective Number of Bits) of 14-bits. The total power consumption of the proposed SDM is $180{\mu}W$.

A High Speed Block Turbo Code Decoding Algorithm and Hardware Architecture Design (고속 블록 터보 코드 복호 알고리즘 및 하드웨어 구조 설계)

  • 유경철;신형식;정윤호;김근회;김재석
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.7
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    • pp.97-103
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    • 2004
  • In this paper, we propose a high speed block turbo code decoding algorithm and an efficient hardware architecture. The multimedia wireless data communication systems need channel codes which have the high-performance error correcting capabilities. Block turbo codes support variable code rates and packet sizes, and show a high performance due to a soft decision iteration decoding of turbo codes. However, block turbo codes have a long decoding time because of the iteration decoding and a complicated extrinsic information operation. The proposed algorithm using the threshold that represents a channel information reduces the long decoding time. After the threshold is decided by a simulation result, the proposed algorithm eliminates the calculation for the bits which have a good channel information and assigns a high reliability value to the bits. The threshold is decided by the absolute mean and the standard deviation of a LLR(Log Likelihood Ratio) in consideration that the LLR distribution is a gaussian one. Also, the proposed algorithm assigns '1', the highest reliable value, to those bits. The hardware design result using verilog HDL reduces a decoding time about 30% in comparison with conventional algorithm, and includes about 20K logic gate and 32Kbit memory sizes.

Design of a 2.5V 300MHz 80dB CMOS VGA Using a New Variable Degeneration Resistor (새로운 가변 Degeneration 저항을 사용한 2.5V 300MHz 80dB CMOS VGA 설계)

  • 권덕기;문요섭;김거성;박종태;유종근
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.9
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    • pp.673-684
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    • 2003
  • A degenerated differential pair has been widely used as a standard topology for digitally programmable CMOS VGAs. A variable degeneration resistor has been implemented using a resistor string or R-2R ladder with MOSFET switches. However, in the VGAs using these conventional methods, low-voltage and high-speed operation is very hard to achieve due to the dc voltage drop over the degeneration resistor. To overcome this problem a new variable degeneration resistor is proposed where the dc voltage drop is almost removed. Using the proposed gain control scheme, a low-voltage and high-speed CMOS VGA is designed. HSPICE simulation results using a 0.25${\mu}{\textrm}{m}$ CMOS process parameters show that the designed VGA provides a 3dB bandwidth of 360MHz and a 80dB gain control range in 2dB step. Gain errors are less than 0.4dB at 200MHz and less than l.4dB at 300MHz. The designed circuit consumes 10.8mA from a 2.5V supply and its die area is 1190${\mu}{\textrm}{m}$${\times}$360${\mu}{\textrm}{m}$.

Development of Water Quality Management System in Daecheong Reservoir Using Geographic Information System (GIS를 이용한 저수지의 수질관리시스템 구축)

  • 한건연;백창현
    • Spatial Information Research
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    • v.12 no.1
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    • pp.13-27
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    • 2004
  • The current industrial development and the increase of population in Daecheong Reservoir basin have produced a rapid increase of wastewater discharge. This has resulted in problem of water quality control and management. Although many efforts have been carried out, reservoir water quality has not significantly improved. In this sense, the development of water quality management system is required to improve reservoir water quality. The goal of this study is to design a GIS-based water quality management system for the scientific water quality control and management in the Daecheong Reservoir. For general water quality analysis, WASP5 model was applied to the Daecheong Reservoir. A sensitivity analysis was made to determine significant parameters and an optimization was made to estimate optimal values. The calibration and verification were performed by using observed water quality data for Daecheong Reservoir. A water quality management system for Daecheong Reservoir was made by connecting the WASP5 model to ArcView. It allows a Windows-based Graphic User Interface(GUI) to implement all operation with regard to water quality analysis. The proposed water quality management system has capability for the on-line data process including water quality simulation, and has a post processor far the reasonable visualization for various output. The modeling system in this study will be an efficient NGIS(National Geographic Information System) far planning of reservoir water quality management.

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Design of Binary Constant Envelope System using the Pre-Coding Scheme in the Multi-User CDMA Communication System (다중 사용자 CDMA 통신 시스템에서 프리코딩 기법을 사용한 2진 정진폭 시스템 설계)

  • 김상우;유흥균;정순기;이상태
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.5
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    • pp.486-492
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    • 2004
  • In this paper, we newly propose the binary CA-CDMA(constant amplitude CDMA) system using pre-coding method to solve the high PAPR problem caused by multi-user signal transmission in the CDMA system. 4-user CA-CDMA, the basis of proposed binary CA-CDMA system, makes binary output signal for 4 input users. It produces the output of binary(${\pm}$2) amplitude by using a parity signal resulting from the XOR operation of 4 users data. Another sub-channel or more bandwidth is not necessary because it is transmitted together with user data and can be easily recovered in the receiver. The extension of the number of users can be possible by the simple repetition of the basic binary 4-user CA-CDMA. For example, binary 16-user CA-CDMA is made easily by allocating the four 4-user CA-CDMA systems in parallel and leading the four outputs to the fifth 4-user CA-CDMA system as input, because the output signal of each 4-user CA-CDMA is also binary. By the same extension procedure, binary 64 and 256-user CA-CDMA systems can be made with the constant amplitude. As a result, the code rate of this proposed CA-CDMA system is just 1 and binary CA-CDMA does not change the transmission rate with the constant output signal(PAPR = 0 ㏈). Therefore, the power efficiency of the HPA can be maximized without the nonlinear distortion. From the simulation results, it is verified that the conventional CDMA system has multi-level output signal, but the proposed binary CA-CDMA system always produces binary output. And it is also found that the BER of conventional CDMA system is increased by nonlinear HPA, but the BER of proposed binary CA-CDMA system is not changed.

Experimental Evaluation of Levitation and Imbalance Compensation for the Magnetic Bearing System Using Discrete Time Q-Parameterization Control (이산시간 Q 매개변수화 제어를 이용한 자기축수 시스템에 대한 부상과 불평형보정의 실험적 평가)

  • ;Fumio Matsumura
    • Journal of KSNVE
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    • v.8 no.5
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    • pp.964-973
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    • 1998
  • In this paper we propose a levitation and imbalance compensation controller design methodology of magnetic bearing system. In order to achieve levitation and elimination of unbalance vibartion in some operation speed we use the discrete-time Q-parameterization control. When rotor speed p = 0 there are no rotor unbalance, with frequency equals to the rotational speed. So in order to make levitatiom we choose the Q-parameterization controller free parameter Q such that the controller has poles on the unit circle at z = 1. However, when rotor speed p $\neq$ 0 there exist sinusoidal disturbance forces, with frequency equals to the rotational speed. So in order to achieve asymptotic rejection of these disturbance forces, the Q-parameterization controller free parameter Q is chosen such that the controller has poles on the unit circle at z = $exp^{ipTs}$ for a certain speed of rotation p ( $T_s$ is the sampling period). First, we introduce the experimental setup employed in this research. Second, we give a mathematical model for the magnetic bearing in difference equation form. Third, we explain the proposed discrete-time Q-parameterization controller design methodology. The controller free parameter Q is assumed to be a proper stable transfer function. Fourth, we show that the controller free parameter which satisfies the design objectives can be obtained by simply solving a set of linear equations rather than solving a complicated optimization problem. Finally, several simulation and experimental results are obtained to evaluate the proposed controller. The results obtained show the effectiveness of the proposed controller in eliminating the unbalance vibrations at the design speed of rotation.

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Development of Signal Control Strategy for Oversaturated Intersections Using Wayside Video Equipment (노변영상장비를 활용한 과포화 신호제어전략 개발)

  • Lee, Hyun;Kim, Won-Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.4
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    • pp.11-21
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    • 2013
  • The conventional real-time signal control strategy for oversaturated situation generally requires a number of detectors at the intersection in order to identify the queue length at each approach. Also, existing strategy for the spillback has limited effect due to the temporal spillback control which only reduce the green split at the approach. In this study, a signal control system utilizing the imagery information from ITS roadside equipment is developed for operation of oversaturated intersections. The strategy calculates the saturation ratio based on the queue length extracted from ITS RSE, and designs the signal control variables according to the saturation ratio. The signal control strategy is divided into two phases: oversaturated and supersaturated. In oversaturated conditions, timing plan for main approach is optimized by the queue length. In oversaturated conditions where spillback might occur, the signal timing is designed in order to avoid the spillback. To increase field adaptability, the strategy is designed to adjust the split length, all-red-time, and clearance time, and keep the major signal control variables intact. The result of the simulation shows that in oversaturated conditions, the improvement is similar to the real-time signal control system. In case of, oversaturated conditions, however, the effect of the strategy is superior to that of a real-time system.

An Energy Balancing Low Power Routing Method for Sensor Network with Fixed Data Acquisition Nodes (고정식 정보획득 노드로 구성된 센서 네트워크에 적용 가능한 에너지 밸런싱 저전력 라우팅 기법)

  • Jeong Gye-Gab;Kim Hwang-Gi;Lee Nam-Il;Kim Jun-Nyun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.6 s.324
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    • pp.59-68
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    • 2004
  • Thanks to the development of microelectromechanical systems(MEMS), wireless communication technology and microsensor technology, it was Possible to manufacture a very small and low costdata acquisition node with sensing function, processing function, wireless communication function and battery. Thus sensor networks begin to be prevailed. The sensor network is a spontaneous system which sets up automatically routing paths and transmits asignificant data to the destination. Sensor nodes requires low-power operation because most of them use a battery as operating power. Sensor nodes transmit a sensing data to the destination. Moreover, they play a router. In fact, because the later consumes more energy than the former, the low-power routing is very important. Sensor networks don't have a routing standard unlike general wireless Ad-hoc networks. So This paper proposes a low-power routing method for anting to sensor networks. It is based on AODV and adapts a method to drop probably RREQ depending on remaining power. We examined it through simulations. From simulation results, we could confirm to reduce power consumption about $10-20\%$ and distribute equally power consumption among nodes.

Implementation of a Ranging Simulator for the ATM-PON Based on ITU-T G.983.1 (G.983.1 기반의 ATM-PON을 위한 Ranging 시뮬레이터 구현)

  • Hong, Jae-Geun;Woo, Man-Sik;Chung, Hae;Kim, Jin-Hee;Yoo, Gun-Il;Kim, Woon-Ha
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.9
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    • pp.12-20
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    • 2001
  • The ATM-PON has an important meaning at next generation access network because the equipment transmits various types of user traffic with a single platform through the passive optical splitter. Ranging is a technology to place all ONUs at the same virtual distance in order to provide the synchronization for the upstream signal in the ATM-PON based on the Time Division Multiplexing (TDM). In this paper, we review the merits of ATM PON and related protocol for the PON operation. We summarize and analyze the steps about the ranging protocol based on ITU-T G.983.1 and implement a simulator that can simulate the ranging procedure based on our modeling. In this paper, we can investigate time requirements of G.983.1 by using the simulator and find out the wasted rate of the bandwidth during the ranging procedure in order to know the influence for ONUs while ATM-PON is in-service. Also, we show that a new ranging scheme reducing window size can avoid the degradation of quality of service of ONUs in service with simulation.

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