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Tx/Rx-ordering-aided efficient sphere decoding for generalized spatial modulation systems (일반화 공간 변조 시스템에서 송신/수신 순서화를 적용한 효율적 구복호 수신기)

  • Lee, Hyeong-yeong;Park, Young-woong;Kim, Jong-min;Moon, Hyun-woo;Lee, Kyungchun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.3
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    • pp.523-529
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    • 2017
  • In this paper, we propose an efficient sphere decoding scheme that reduces computational complexity by combining receive and transmit ordering techniques in generalized spatial modulation systems, where the indexes of activated transmit antennas as well as the transmit symbols are exploited to transfer information to the receiver. In this scheme, the receive signals are optimally ordered so that the calculation for a candidate solution outside the sphere is terminated early to lower the computational complexity. In addition, the transmit ordering technique is applied to first search for candidate symbols and activated antennas having higher probabilities to further reduce the computational complexity. Simulation results show that the proposed doubly ordered sphere decoding scheme provides the same bit error rate performance with the conventional sphere decoding method and the sphere decoder employing only the receive ordering technique while it requires lower computational complexity.

Design and implementation of Robot Soccer Agent Based on Reinforcement Learning (강화 학습에 기초한 로봇 축구 에이전트의 설계 및 구현)

  • Kim, In-Cheol
    • The KIPS Transactions:PartB
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    • v.9B no.2
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    • pp.139-146
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    • 2002
  • The robot soccer simulation game is a dynamic multi-agent environment. In this paper we suggest a new reinforcement learning approach to each agent's dynamic positioning in such dynamic environment. Reinforcement learning is the machine learning in which an agent learns from indirect, delayed reward an optimal policy to choose sequences of actions that produce the greatest cumulative reward. Therefore the reinforcement learning is different from supervised learning in the sense that there is no presentation of input-output pairs as training examples. Furthermore, model-free reinforcement learning algorithms like Q-learning do not require defining or learning any models of the surrounding environment. Nevertheless these algorithms can learn the optimal policy if the agent can visit every state-action pair infinitely. However, the biggest problem of monolithic reinforcement learning is that its straightforward applications do not successfully scale up to more complex environments due to the intractable large space of states. In order to address this problem, we suggest Adaptive Mediation-based Modular Q-Learning (AMMQL) as an improvement of the existing Modular Q-Learning (MQL). While simple modular Q-learning combines the results from each learning module in a fixed way, AMMQL combines them in a more flexible way by assigning different weight to each module according to its contribution to rewards. Therefore in addition to resolving the problem of large state space effectively, AMMQL can show higher adaptability to environmental changes than pure MQL. In this paper we use the AMMQL algorithn as a learning method for dynamic positioning of the robot soccer agent, and implement a robot soccer agent system called Cogitoniks.

THE ROLE OF SATELLITE REMOTE SENSING TO DETECT AND ASSESS THE DAMAGE OF TSUNAMI DISASTER

  • Siripong, Absornsuda
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.827-830
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    • 2006
  • The tsunami from the megathrust earthquake magnitude 9.3 on 26 December 2004 is the largest tsunami the world has known in over forty years. This tsunami destructively attacked 13 countries around Indian Ocean with at least 230,000 fatalities, displaced people 2,089,883 and 1.5 million people who lost their livelihoods. The ratio of women and children killed to men is 3 to 1. The total damage costs US10.73billionandrebuildingcostsUS 10.375 billion. The tsunami's death toll could have been drastically reduced, if the warning was disseminated quickly and effectively to the coastal dwellers along the Indian Ocean rim. With a warning system in Indian Ocean similar to that operating in the Pacific Ocean since 1965, it would have been possible to warn, evacuate and save countless lives. The best tribute we can pay to all who perished or suffered in this disaster is to heed its powerful lessons. UNESCO/IOC have put their tremendous effort on better disaster preparedness, functional early warning systems and realistic arrangements to cope with tsunami disaster. They organized ICG/IOTWS (Indian Ocean Tsunami Warning System) and the third of this meeting is held in Bali, Indonesia during 31st July to 4th August 2006. A US$ 53 million interim warning system using tidal gauges and undersea sensors is nearing completion in the Indian Ocean with the assistance from IOC. The tsunami warning depends strictly on an early detection of a tsunami (wave) perturbation in the ocean itself. It does not and cannot depend on seismological information alone. In the case of 26 December 2004 tsunami when the NOAA/PMEL DART (Deep-ocean Assessment and Reporting of Tsunami) system has not been deployed, the initialized input of sea surface perturbation for the MOST (Method Of Splitting Tsunami) model was from the tsunamigenic-earthquake source model. It is the first time that the satellite altimeters can detect the signal of tsunami wave in the Bay of Bengal and was used to validate the output from the MOST model in the deep ocean. In the case of Thailand, the inundation part of the MOST model was run from Sumatra 2004 for inundation mapping purposes. The medium and high resolution satellite data were used to assess the degree of the damage from Indian Ocean tsunami of 2004 with NDVI classification at 6 provinces on the Andaman seacoast of Thailand. With the tide-gauge station data, run-up surveys, bathymetry and coastal topography data and land-use classification from satellite imageries, we can use these information for coastal zone management on evacuation plan and construction code.

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Millimeter-wave Broadband Amplifier integrating Shunt Peaking Technology with Cascode Configuration (Cascode 구조에 Shunt Peaking 기술을 접목시킨 밀리미터파 광대역 Amplifier)

  • Kwon, Hyuk-Ja;An, Dan;Lee, Mun-Kyo;Lee, Sang-Jin;Moon, Sung-Woon;Baek, Tae-Jong;Park, Hyun-Chang;Rhee, Jin-Koo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.10 s.352
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    • pp.90-97
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    • 2006
  • We report our research work on the millimeter-wave broadband amplifier integrating the shunt peaking technology with the cascode configuration. The millimeter-wave broadband cascode amplifier on MIMIC technology was designed and fabricated using 0.1μmΓgate GaAs PHEMT, CPW, and passive library. The fabricated PHEMT has shown a transconductance of 346.3 mS/mm, a current gain cut off frequency (fT) of 113 GHz, and a maximum oscillation frequency (fmax) of 180 GHz. To prevent oscillation of designed cascode amplifier, a parallel resistor and capacitor were connected to drain of common-gate device. For expansion of the bandwidth and flatness of the gain, we inserted the short stub into bias circuits and the compensation transmission line between common-source device and common-gate device, and then their lengths were optimized. Also, the input and output stages were designed using the matching method to obtain the broadband characteristic. From the measurement, we could confirm to extend bandwidth and flat gain by integrating the shunt peaking technology with the cascode configuration. The cascode amplifier shows the broadband characteristic from 19 GHz to 53.5 GHz. Also, the average gain of this amplifier is about 6.5 dB over the bandwidth.

An Aggregate Three Color Marker without Per Flow Management for End-to-End QoS Improvement of Assured Service in DiffServ (DiffServ 방식에서 플로별 관리 없이 Assured Service의 End-to-End QoS를 향상하기위한 Aggregate Three Color Marker)

  • Hur, Kyeong;Park, Ji-Hoon;Roh, Young-Sup;Eom, Doo-Seop;Tchah, Kyun-Hyon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.6B
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    • pp.588-603
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    • 2003
  • In this paper, we propose an Aggregate Three Color Marker without per flow management which is required for an Edge router to improve End-to-End QoS of Assured Service in DiffServ. Proposed Aggregate Three Color Marker is used with the Adaptive RIO-DC scheme to achieve the minimum rate guarantee without per flow management. Assuming that the admission control for Assured Service has been performed, proposed Aggregate Three Color Marker measures incoming In-profile traffic rate at the output link of an edge router using a token-bucket with a token rate equal to the sum of contracted rates of admitted flows passing the edge router. If there are token losses from the token bucket, out-of-profile packets are promoted to Yellow packets within the aggregate traffic profile. And yellow packets are demoted to out-of-profile packets at the input link to an Edge router fer the purpose of fairness maintenance. In-profile packets and Yellow packets are processed identically at the RIO-DC buffer management scheme in our proposed method. Simulation results show that through using proposed Aggregate Three Color Marker with the Adaptive RIO-DC scheme, the minimum rate guarantee for Assured Service can be achieved without per flow management at multiple DiffServ domains.

A Technique for Reducing the Size of Microwave Amplifiers using Spiral-Shaped Defected Ground Structure (맴돌이형 결함접지구조를 이용한 마이크로파 증폭기의 소형화 방법)

  • Lim, Jong-Sik;Jeong, Yong-Chae;Ahn, Dal;Nam, Sang-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.9
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    • pp.904-911
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    • 2003
  • A new method to reduce the size of microwave amplifiers spiral-shaped defected ground structure(Spiral-DGS) is proposed. A microstrip line having Spiral-DGS on the ground plane produces increased slow-wave factor and electrical length for the fixed physical length. In addition, it provides an excellent rejection characteristic for a finite frequency band like band rejection filters. The rejection band is used for rejecting harmonic components of amplifiers. The reduced microstrip line lengths in matching networks by Spiral-DGS are 39 % and 44 % of the original ones in input and output matching networks, respectively. It is shown that the measured S-parameters of the reduced amplifier agree well with those of the original amplifier. The measured second harmonic of the reduced amplifier is much less than that of the original amplifier by at least 10 dB. The same technique is applied to reject the third harmonic using the proper Spiral-DGS for the third harmonic frequency. The measured third harmonic is smaller than that of the original amplifier by 25 dB.

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 3rd 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 3rd 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(CI) 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 180μW.

Design of a Low Phase Noise Vt-DRO Based on Improvement of Dielectric Resonator Coupling Structure (유전체 공진기 결합 구조 개선을 통한 저위상 잡음 전압 제어 유전체 공진기 발진기 설계)

  • Son, Beom-Ik;Jeong, Hae-Chang;Lee, Seok-Jeong;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.6
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    • pp.691-699
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    • 2012
  • In this paper, we present a Vt-DRO with a low phase noise, which is achieved by improving the coupling structure between the dielectric resonator and microstrip line. The Vt-DRO is a closed-loop type and is composed of 3 blocks; dielectric resonator, phase shifter, and amplifier. We propose a mathematical estimation method of phase noise, using the group delay of the resonator. By modifying the coupling structure between the dielectric resonator and microstrip line, we achieved a group delay of 53 nsec. For convenience of measurement, wafer probes were inserted at each stage to measure the S-parameters of each block. The measured S-parameter of the Vt-DRO satisfies the open-loop oscillation condition. The Vt-DRO was implemented by connecting the input and output of the designed open-loop to form a closed-loop. As a result, the phase noise of the Vt-DRO was measured as -132.7 dBc/Hz(@ 100 kHz offset frequency), which approximates the predicted result at the center frequency of 5.3 GHz. The tuning-range of the Vt-DRO is about 5 MHz for tuning voltage of 0~10 V and the power is 4.5 dBm. PFTN-FOM is -31 dBm.

Color Reproduction in DLP Projector using Hue Shift Model according to Additional White Channel (화이트 채널 추가에 따른 색상이동모델를 이용한 DLP 프로젝터의 색 재현)

  • Park, Il-Su;Ha, Ho-Gun;Ha, Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.4
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    • pp.40-48
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    • 2012
  • This paper models the hue shift phenomenon and proposes a hue correction method to give perceptual matching between projector with and without additional white channel. To quantify the hue shift phenomenon for whole hue angle, 24 color patches with the same lightness are frist created along equally-spaced hue angle, and these are displayed one by one both displays with different luminance levels. Next, each hue value of the patches appeared on the projector with additional white channel is adjusted by observers until the hue values of patches on both displays appear the same visually. After obtaining the hue shift values from the color matching experiment, these values are piecewise fit into six polynomial functions, which approximately determine shifted hue amounts for an arbitrary hue values of each pixel in projector with additional white channel and are utilized to correct them. Actually, an input RGB image is converted to CIELAB LCH color space to get hue values of each pixel and this hue value is shifted as much as the amount calculated by the functions of hue shift model for correction. Finally, corrected image is inversely converted to an output RGB image. For an evaluation, the matching experiment with several test images and the z-score comparisons were performed.

Development of a Freeway Travel Time Forecasting Model for Long Distance Section with Due Regard to Time-lag (시간처짐현상을 고려한 장거리구간 통행시간 예측 모형 개발)

  • 이의은;김정현
    • Journal of Korean Society of Transportation
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    • v.20 no.4
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    • pp.51-61
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    • 2002
  • In this dissertation, We demonstrated the Travel Time forecasting model in the freeway of multi-section with regard of drives' attitude. Recently, the forecasted travel time that is furnished based on expected travel time data and advanced experiment isn't being able to reflect the time-lag phenomenon specially in case of long distance trip, so drivers don't believe any more forecasted travel time. And that's why the effects of ATIS(Advanced Traveler Information System) are reduced. Therefore, in this dissertation to forecast the travel time of the freeway of multi-section reflecting the time-lag phenomenon & the delay of tollgate, we used traffic volume data & TCS data that are collected by Korea Highway Cooperation. Also keep the data of mixed unusual to applicate real system. The applied model for forecasting is consisted of feed-forward structure which has three input units & two output units and the back-propagation is utilized as studying method. Furthermore, the optimal alternative was chosen through the twelve alternative ideas which is composed of the unit number of hidden-layer & repeating number which affect studying speed & forecasting capability. In order to compare the forecasting capability of developed ANN model. the algorithm which are currently used as an information source for freeway travel time. During the comparison with reference model, MSE, MARE, MAE & T-test were executed, as the result, the model which utilized the artificial neural network performed more superior forecasting capability among the comparison index. Moreover, the calculated through the particularity of data structure which was used in this experiment.