• Title/Summary/Keyword: time-synchronization

Search Result 1,153, Processing Time 0.023 seconds

Effects of Learning Motivation on the Stress Coping Style and Stress of Test (학습동기가 시험 스트레스와 스트레스 대처 양식에 미치는 영향)

  • Jang, Chel;Lee, Eunhye;Cheon, Jisu
    • Journal of The Korean Society of Integrative Medicine
    • /
    • v.2 no.2
    • /
    • pp.89-96
    • /
    • 2014
  • Purpose : In this study, we selected three research subjects to attempt to clear learning motivation of college students is what impact the stress coping style and stress test. First, age, gender, the future career after graduation, the presence or absence of part-time job is, its impact on learning motivation. Second, learning motivation is what effect the stress of the test. Third, based on the motivation of learning, how deal pursuing efforts form the social support, the center of the problem-solving approach, seeking to avoid the reaction to stress how different form. Methods : K University occupational therapy and one, two, three grade 100 students (male 22 people, female 78) to target age, sex, and after graduation, part-time status, motivation, stress, stress coping style questionnaire for distribution and was written. Results : First of all, women's social support form graduation course, more robust than pursue blank after the synchronization uncertainty and stress, and graduated from the trading center and avoid the use of career, more form. Second, motivation and stress test, a difference between the notice could not see. Third, the higher the motivation of learning, problem-solving, Action form to the center to use as many as you, but avoid using too much in the center form is addressed. Conclusion : As a result of the study that came out of the course after graduating from ensure that learning motivation is high, the more the uncertainty, the more to cope with stress in the center of the form to avoid form address was used. Because of this, the student careers after graduation, to make sure that can help you to compare efforts over is believed to be necessary.

A Packet Collision Avoidance Technique in IEEE1609.4 Based Time Synchronization Multi-channel Environment (IEEE1609.4 기반 시간 동기 멀티채널 환경에서의 패킷 충돌 회피 기법)

  • Jin, Seong-Keun;Lim, Ki-Taeg;Shin, Dae-Kyo;Yoon, Sang-Hun;Jung, Han-Gyun
    • Journal of IKEEE
    • /
    • v.19 no.3
    • /
    • pp.385-391
    • /
    • 2015
  • In this paper, we analyze the communication performance in a time synchronous multi-channel environment and deal with a packet collision avoidance technique to improve it based on IEEE1609.4 for increasing the efficiency of the control channel IEEE802.11p WAVE communication system. In previous works, they tried to solve this problem by message scheduling method on application layer software or changing the value of the random back-off optionally Contention Window. In this paper, we propose a method for adjusting the Channel Guard Interval for packet collision avoidance. The performance was evaluated by the actual vehicle test. The result was confirmed performance over 90% PDR(Packet Delivery Ratio).

A Jet Strobe Signal Timing Control of Ink Jet Printer Head for Enhancement of Printing Speed and Quality (인쇄 속도 향상과 화질 개선을 위한 잉크젯 프린터 헤드의 액적 분사 신호 타이밍 제어)

  • Cho, Young-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.15 no.8
    • /
    • pp.1727-1734
    • /
    • 2011
  • In this paper, a position control scheme of the ink droplet is presented for the high image quality and print speed ink jet printer. The proposed scheme estimates the impact position and compensates it by control of the jet strobe time based on the dynamic equations describing the moving trajectory of the ejected ink droplet. Compared to the conventional jet strobe control which is based on the simple synchronization with the position signal of the ink jet nozzle, the proposed control scheme provides more accurate impact position control while the carrier is moving with accelerated or decelerated speed as well as steady state speed with fluctuations. The availability of printing during the acceleration and deceleration states of the carrier moving enables the print speed up and the frame size down which means the cost down.

Speech Quality Measure for VoIP Using Wavelet Based Bark Coherence Function (웨이블렛 기반 바크 코히어런스 함수를 이용한 VoIP 음질평가)

  • 박상욱;박영철;윤대희
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.27 no.4A
    • /
    • pp.310-315
    • /
    • 2002
  • The Bark Coherence Function (BCF) defies a coherence function within perceptual domain as a new cognition module, robust to linear distortions due to the analog interface of digital mobile system. Our previous experiments have shown the superiority of BCF over current measures. In this paper, a new BCF suitable for VoIP is developed. The unproved BCF is based on the wavelet series expansion that provides good frequency resolution while keeping good time locality. The proposed Wavelet based Bark Coherence function (WBCF) is robust to variable delay often observed in packet-based telephony such as Voice over Internet Protocol (VoIP). We also show that the refinement of time synchronization after signal decomposition can improve the performance of the WBCF. The regression analysis was performed with VoIP speech data. The correlation coefficients and the standard error of estimates computed using the WBCF showed noticeable improvement over the Perceptual Speech Quality Measure (PSQM) that is recommended by ITU-T.

Quantization Data Transmission for Optimal Path Search of Multi Nodes in cloud Environment (클라우드 환경에서 멀티 노드들의 최적 경로 탐색을 위한 양자화 데이터 전송)

  • Oh, HyungChang;Kim, JaeKwon;Kim, TaeYoung;Lee, JongSik
    • Journal of the Korea Society for Simulation
    • /
    • v.22 no.2
    • /
    • pp.53-62
    • /
    • 2013
  • Cloud environment is one in the field of distributed computing and it consists of physical nodes and virtual nodes. In distributed cloud environment, an optimal path search is that each node to perform a search for an optimal path. Synchronization of each node is required for the optimal path search via fast data transmission because of real-time environment. Therefore, a quantization technique is required in order to guarantee QoS(Quality of Service) and search an optimal path. The quantization technique speeds search data transmission of each node. So a main server can transfer data of real-time environment to each node quickly and the nodes can perform to search optimal paths smoothly. In this paper, we propose the quantization technique to solve the search problem. The quantization technique can reduce the total data transmission. In order to experiment the optimal path search system which applied the quantized data transmission, we construct a simulation of cloud environment. Quantization applied cloud environment reduces the amount of data that transferred, and then QoS of an application for the optimal path search problem is guaranteed.

A Synchronized Job Assignment Model for Manual Assembly Lines Using Multi-Objective Simulation Integrated Hybrid Genetic Algorithm (MO-SHGA) (다목적 시뮬레이션 통합 하이브리드 유전자 알고리즘을 사용한 수동 조립라인의 동기 작업 모델)

  • Imran, Muhammad;Kang, Changwook
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.40 no.4
    • /
    • pp.211-220
    • /
    • 2017
  • The application of the theoretical model to real assembly lines has been one of the biggest challenges for researchers and industrial engineers. There should be some realistic approach to achieve the conflicting objectives on real systems. Therefore, in this paper, a model is developed to synchronize a real system (A discrete event simulation model) with a theoretical model (An optimization model). This synchronization will enable the realistic optimization of systems. A job assignment model of the assembly line is formulated for the evaluation of proposed realistic optimization to achieve multiple conflicting objectives. The objectives, fluctuation in cycle time, throughput, labor cost, energy cost, teamwork and deviation in the skill level of operators have been modeled mathematically. To solve the formulated mathematical model, a multi-objective simulation integrated hybrid genetic algorithm (MO-SHGA) is proposed. In MO-SHGA each individual in each population acts as an input scenario of simulation. Also, it is very difficult to assign weights to the objective function in the traditional multi-objective GA because of pareto fronts. Therefore, we have proposed a probabilistic based linearization and multi-objective to single objective conversion method at population evolution phase. The performance of MO-SHGA is evaluated with the standard multi-objective genetic algorithm (MO-GA) with both deterministic and stochastic data settings. A case study of the goalkeeping gloves assembly line is also presented as a numerical example which is solved using MO-SHGA and MO-GA. The proposed research is useful for the development of synchronized human based assembly lines for real time monitoring, optimization, and control.

Metastability Window Measurement of CMOS D-FF Using Bisection (이분법을 이용한 CMOS D-FF의 불안정상태 구간 측정)

  • Kim, Kang-Chul;Chong, Jiang
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.12 no.2
    • /
    • pp.273-280
    • /
    • 2017
  • As massive integration technology of transistors has been developing, multi-core circuit is fabricated on a silicon chip and a clock frequency is getting faster to meet the system requirement. But increasing the clock frequency can induce some problems to violate the operation of system such as clock synchronization, so it is very import to avoid metastability events to design digital chips. In this paper, metastability windows are measured by bisection method in H-spice depending on temperature, supply voltage, and the size of transmission gate with D-FF designed with 180nm CMOS process. The simulation results show that the metastability window(: MW) is slightly increasing to temperature and supply voltage, but is quadratic to the area of a transmission gate, and the best area ration of P and Ntransitor in transmission gate is P/N=4/2 to get the least MW.

Performance Analysis of Initial Cell Search in WCDMA System over Rayleigh Fading Channels (레일리 페이딩 채널에서 W-CDMA 시스템의 초기 셀 탐색 성능 해석)

  • Song, Moon-Kyou
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.38 no.4
    • /
    • pp.1-10
    • /
    • 2001
  • The 3-step cell search has been considered for fast acquisition of the scrambling code unique to a cell in the W -CDMA system. In this paper, the performance of the cell search scheme is analyzed in Rayleigh fading channels. And the system parameters for cell search scheme and the design parameters for the receivers are examined. The probabilities of detection, miss and false alarm for each step are derived in closed forms based on the statistics of CDMA noncoherent demodulator output. Through the analysis, the effect of threshold setting and post detection integration for each step is investigated, and the optimal values of the power allocation for the synchronization channels are also considered. The number of post-detection integrations for each step is a design parameter for the receiver, and the optimum values may depend on not only the power allocation for each channel related to the cell search, but the false alarm penalty time. It is shown that optimal values could be determined through the analysis. Also, the cumulative probability distribution of the average cell search time is obtained.

  • PDF

A Study on Complex Field Network Coding Scheme for Wireless Relay System (무선 릴레이 시스템에서의 Complex Field Network Coding 기법 적용에 관한 연구)

  • Hwang, Won-Jun;Jang, Jun-Hee;Choi, Hyung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.36 no.4C
    • /
    • pp.241-253
    • /
    • 2011
  • In this paper, a CFNC (Complex Field Network Coding) scheme is presented, which focuses on improving transmission efficiency by reducing time slots that are needed to exchange data frames. Conventional CFNC scheme has the advantage of minimizing the number of time slots required for information exchanges. However, there exists serious performance deterioration because the transmit signals are interfered with each other. Moreover, when CFNC scheme is applied, the estimation and compensation performance of fine frequency offset severely deteriorates due to the multiple frequency offsets in received signal of relay node. In order to overcome these critical problems, we propose an improved CFNC scheme with modified maximum likelihood decision method which uses uplink transmit diversity. Also, we propose an enhanced fine frequency offset estimation method and a corresponding compensation method to deal with the multiple frequency offsets. Corresponding simulation results verify that the proposed methods are able to effectively solve the problems of CFNC scheme.

Router Algorithms for Improving Fairness in Differentiated Services (인터넷 차별화 서비스를 위한 라우터의 공평성 향상 알고리즘)

  • Nam, Dong-Ho;Choi, Young-Soo;Kim, Byung-Chul;Cho, You-Ze
    • Journal of KIISE:Information Networking
    • /
    • v.29 no.4
    • /
    • pp.358-367
    • /
    • 2002
  • The IETF Differentiated Services (Diffserv) WG focused on Providing service differentiation on the Internet. One problem of the Diffserv Assured Services (AS) architecture is that it cannot guarantee fairness and throughput assurance. In this paper, we propose two schemes for guaranteeing fairness among the various target rates in the AS architecture. One is a variant of RED with IN and OUT (RIO), called the improved RIO (IRIO). The other is a variant of Time Sliding Window (TSW), called the improved TSW (ITSW). To validate the Proposed schemes, their behaviors are then examined under various simulation environments. The simulation results showed that IRIO and ITSW improved fairness and the throughput assurance in the AS architecture.