• Title/Summary/Keyword: Locking Control

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Consolidation of Metro Networks and Access Networks by using Long-reach WDM-PON (장거리 전송 파장분할 다중방식 수동형 광가입자망을 이용한 메트로망과 가입자망 통합 방안)

  • Lee Sang-Mook;Mun Sil-Gu;Kim Min-Hwan;Lee Chang-Hee
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.5 s.347
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    • pp.59-67
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    • 2006
  • We demonstrate bidirectional long-reach 35-channel dense wavelength division multiplexing-passive optical network(DWDM-PON) based on wavelength-locked Fabry-Perot laser diodes (F-P LDs). The mode control of F-P LD enhances output power at decreased the required injection power. We show packet-loss-free transmission in all 70 channels at 125 Mb/s per channel line rate through 70 km of single mode fiber without optical amplifier The DWDM-PON can consolidate a metro network into an access network by bypassing the central offices within its reach. The proposed DWDM-PON can accommodate about 80 subscribers with an EDFA-based broadband light source. Further expansion up to 100 subscribers is possible with a semiconductor-based BLS.

An Effective Method Guaranteeing Mutual Exclusion of Lock Waiting Information for Deadlock Detection in Main Memory Databases (주기억장치 데이타베이스에서 교착 상태의 검출을 위한 락 대기 정보의 효과적인 상호 배제 기법)

  • Kim, Sang-Wook;Lee, Seung-Sun;Choi, Wan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7B
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    • pp.1313-1321
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    • 1999
  • The two-phase locking protocol(2PL) is the most widely-used concurrency control mechanism for guaranteeing logical consistency of data in a database environment where a number of transactions perform concurrently. The problem inherent in the 2PL protocol is a deadlock, where a set of transactions holding some locks indefinitely wait an additional lock that is already held by other transactions in the set. The deadlock detector is a DBMS sub-component that examines periodically whether a system is in a deadlock state based on lock waiting information of transactions. The deadlock detector and transactions execute concurrently in a DBMS and read and/or write the lock waiting information simultaneously. Since the lock waiting information is a shared one, we need an efficient method guaranteeing its physical consistency by using mutual exclusion. The efficiency of the mutual exclusion method is crucial especially in a main memory DBMS with high performance since it seriously affects the performance of an entire system. In this paper, we propose a new method that effectively guarantees physical consistency of lock waiting information. Two primary goals of our method are to minimize the processing overhead and to maximize system concurrency.

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Wide Range Analog Dual-Loop Delay-Locked Loop (광대역 아날로그 이중 루프 Delay-Locked Loop)

  • Lee, Seok-Ho;Kim, Sam-Dong;Hwang, In-Seok
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.44 no.1
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    • pp.74-84
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    • 2007
  • This paper presents a new dual-loop Delay Locked Loop(DLL) to expand the delay lock range of a conventional DLL. The proposed dual-loop DLL contains a Coarse_loop and a Fine_loop, and its operation utilizes one of the loops selected by comparing the initial time-difference among the reference clock and 2 internal clocks. The 2 internal clock signals are taken, respectively, at the midpoint and endpoint of a VCDL and thus are $180^{\circ}$ separated in phase. When the proposed DLL is out of the conventional lock range, the Coarse_loop is selected to push the DLL in the conventional lock range and then the Fine_loop is used to complete the locking process. Therefore, the proposed DLL is always stably locked in unless it is harmonically false-locked. Since the VCDL employed in the proposed DLL needs two control voltages to adjust the delay time, it uses TG-based inverters, instead of conventional, multi-stacked, current-starved inverters, to compose the delay line. The new VCDL provides a wider delay range than a conventional VCDL In overall, the proposed DLL demonstrates a more than 2 times wider lock range than a conventional DLL. The proposed DLL circuits have been designed, simulated and proved using 0.18um, 1.8V TSMC CMOS library and its operation frequency range is 100MHz${\sim}$1GHz. Finally, the maximum phase error of the DLL locked in at 1GHz is less than 11.2ps showing a high resolution and the simulated power consumption is 11.5mW.

A 0.4-2GHz, Seamless Frequency Tracking controlled Dual-loop digital PLL (0.4-2GHz, Seamless 주파수 트래킹 제어 이중 루프 디지털 PLL)

  • Son, Young-Sang;Lim, Ji-Hoon;Ha, Jong-Chan;Wee, Jae-Kyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.12
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    • pp.65-72
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    • 2008
  • This paper proposes a new dual-loop digital PLL(DPLL) using seamless frequency tracking methods. The dual-loop construction, which is composed of the coarse and fine loop for fast locking time and a switching noise suppression, is used successive approximation register technique and TDC. The proposed DPLL in order to compensate the quality of jitter which follows long-term of input frequency is newly added cord conversion frequency tracking method. Also, this DPLL has VCO circuitry consisting of digitally controlled V-I converter and current-control oscillator (CCO) for robust jitter characteristics and wide lock range. The chip is fabricated with Dongbu HiTek $0.18-{\mu}m$ CMOS technology. Its operation range has the wide operation range of 0.4-2GHz and the area of $0.18mm^2$. It shows the peak-to-peak period jitter of 2 psec under no power noise and the power dissipation of 18mW at 2GHz through HSPICE simulation.

Clinical Assessment of Patients with Mandibular Condyle hypoplasia (하악 과두저형성증 환자의 임상적 평가)

  • Yi, Young-Chul;Cho, Bong-Hae;Ok, Soo-Min;Heo, Jun-Young;Kim, Kyung-Hee;Ahn, Young-Woo;Ko, Myung-Yun;Jeong, Sung-Hee
    • Journal of Oral Medicine and Pain
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    • v.38 no.2
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    • pp.175-185
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    • 2013
  • Objective : Condyle hypoplasia in temporomandibular joint(TMJ) is often observed in several radiographic views. Mandibular Condyle hypoplasia is frequently confused with osteoarthritis with bony changes in TMJ. This paper investigated clinical characteristics of mandibular condyle hypoplasia as compared with TMJ osteoarthritis. Material and method : 276 patients with TMD were taken clinical and radiological examination and were divided into study group, 189 patients diagnosed with mandibular condyle hypoplasia, and control group, 87 patients diagnosed with TMJ osteoarthritis. And clinical features(Onset, Overjet, Overbite, Noise, Locking, NAS of noise, LOM, pain, MCO, and site of diagnosis and pain)of the two groups were compared. Results : 1. Mandibular condyle hypoplasia and TMJ osteoarthritis were similar in many of the clinical features. 2. Mandibular condyle hypoplasia concordance rates of the radiographic diagnosis site and the pain site was significantly lower than TMJ osteoarthritis. 3. Bilateral mandibular condyle hypoplasia group had more occlusal discomfort, and clenching habits than unilateral mandibular condyle hypoplasia group. 4. Unilateral mandibular condyle hypoplasia group had more unilateral chewing habits and LOM than unilateral TMJ osteoarthritis group. Unilateral TMJ osteoarthritis group had more morning stiffness and higher concordance rates of the radiographic diagnosis site and the click sound site than unilateral mandibular condyle hypoplasia group. 5. Bilateral mandibular condyle hypoplasia group had more usual headaches and overjet than bilateral TMJ osteoarthritis group. Conclusion : Mandibular condyle hypoplasia has somewhat distinguishing clinical characteristics as compared with TMJ osteoarthritis.

3-channel Tiled-aperture Coherent-beam-combining System Based on Target-in-the-loop Monitoring and SPGD Algorithm (목표물 신호 모니터링 및 SPGD 알고리즘 기반 3 채널 타일형 결맞음 빔결합 시스템 연구)

  • Kim, Youngchan;Yun, Youngsun;Kim, Hansol;Chang, Hanbyul;Park, Jaedeok;Choe, Yunjin;Na, Jeongkyun;Yi, Joohan;Kang, Hyungu;Yeo, Minsu;Choi, Kyuhong;Noh, Young-Chul;Jeong, Yoonchan;Lee, Hyuk-Jae;Yu, Bong-Ahn;Yeom, Dong-Il;Jun, Changsu
    • Korean Journal of Optics and Photonics
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    • v.32 no.1
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    • pp.1-8
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    • 2021
  • We have studied a tiled-aperture coherent-beam-combining system based on constructive interference, as a way to overcome the power limitation of a single laser. A 1-watt-level, 3-channel coherent fiber laser and a 3-channel fiber array of triangular tiling with tip-tilt function were developed. A monitoring system, phase controller, and 3-channel phase modulator formed a closed-loop control system, and the SPGD algorithm was applied. Eventually, phase-locking with a rate of 5-67 kHz and peak-intensity efficiency comparable to the ideal case of 53.3% was successfully realized. We were able to develop the essential elements for a tiled-aperture coherent-beam-combining system that had the potential for highest output power without any beam-combining components, and a multichannel coherent-beam-combining system with higher output power and high speed is anticipated in the future.