• Title/Summary/Keyword: Lock-in Method

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A Lock Mechanism for HiPi-bus Based Multiprocessor Systems (HiPi-bus 구조의 다중 프로세서 시스템에서의 잠금장치)

  • 윤용호;임인칠
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.2
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    • pp.33-43
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    • 1993
  • Lock mechanism is essential for synchronization on the multiprocessor systems. Lock mechanism needs to reduce the time for lock operation in low lock contention. Lock mechanism must consider the case of the high lock contention. The conventional lock control scheme in memory results in the increase of bus traffic and memory utilization in lock operation. This paper suggests a lock scheme which stores the lock data in cache and manages it efficiently to reduce the time spent in lock operation when the lock contention is low on a multiprocessor system built on HiPi-bus(Highly Pipelined bus). This paper also presents the design of the HIPi-CLOCK (Highly Pipelined bus Cache LOCK mechanism) which transfere the data from on cache to another when the lock contention is high. The designed simulator compares the conventional lock scheme which controls the lock in memory with the suggested HiPi-CLOCK scheme in terms of the RMW(Read-Modify-Write) operation time using simulated trace. It is shown that the suggested lock control scheme performance is over twice than that of the conventional method in low lock contention. When the lock contention is high, the performance of the suggested scheme increases as the number of the shared lock data increases.

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Numerical Research on the Lock-in Compensation Method of a Ring Laser Gyroscope for Reducing INS Alignment Time (관성항법장치 초기정렬시간 단축을 위한 링레이저 자이로 lock-in오차 보상방법의 수치해석적인 분석)

  • Shim, Kyu-Min;Jang, Suk-Won;Paik, Bok-Soo;Chung, Tae-Ho;Moon, Hong-Key
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.3
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    • pp.275-282
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    • 2009
  • Generally, the sinusoidal cavity dither is adopted to ring laser gyroscope for eliminating the lock-in which is non-linear effect at the small rotation input. Despite this method, there are some remained errors which are generated at the dither turnaround, and those errors produce random walk which is a general character of a ring laser gyroscope. As one of the numerous research results for compensating these errors, there is a special lock-in compensation method which is the method of error estimation and compensation by comparing the beat signal periods of before and after the dither turnarounds. In this paper, by ring laser gyroscope modeling and numerical analysis, we verified the theoretical validity and confirmed the effectiveness of this method in expectation of the possible beat signal measurement time resolution. As a result, we confirmed the random walk decreases from a-half to a-third by this lock-in compensation method. So, it is expected to be a remarkable method for reducing the INS alignment time.

Software-based Simple Lock-in Amplifier and Built-in Sound Card for Compact and Cost-effective Terahertz Time-domain Spectroscopy System

  • Yu-Jin Nam;Jisoo Kyoung
    • Current Optics and Photonics
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    • v.7 no.6
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    • pp.683-691
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    • 2023
  • A typical terahertz time-domain spectroscopy system requires large, expensive, and heavy hardware such as a lock-in amplifier and a function generator. In this study, we replaced the lock-in amplifier and the function generator with a single sound card built into a typical desktop computer to significantly reduce the system size, weight, and cost. The sound card serves two purposes: 1 kHz chopping signal generation and raw data acquisition. A unique software lock-in (Python coding program to eliminate noise from raw data) method was developed and successfully extracted THz time-domain signals with a signal-to-noise ratio of ~40,000 (the intensity ratio between the peak and average noise levels). The built-in sound card with the software lock-in method exhibited sufficiently good performance compared with the hardware-based method.

A NUMERICAL STUDY ON THE ROLL LOCK-IN OF A CANARD-CONTROLLED MISSILE WITH FREELY SPINNING TAILFINS (자유회전 테일핀을 갖는 미사일에 대한 Roll Lock-in 현상의 수치적 연구)

  • Yang, Y.R.;Kim, M.S.;Myong, R.S.;Cho, T.H.
    • Journal of computational fluids engineering
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    • v.14 no.4
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    • pp.48-55
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    • 2009
  • In this study, roll lock-in phenomena of freely spinning tailfins were investigated by a CFD code. To analyze a motion of freely spinning tailfins, this research use a Chimera method, an Euler code and a 6 degrees of freedom analysis. The numerical results of aerodynamic characteristics and roll rates of a canard-controlled missile with freely spinning tailfins show a good agreement with wind tunnel test results. Using the roll rates calculation result of freely spinning tailfins, roll lock-in phenomena is confirmed. Roll lock-in phenomena and Roll lock-in states can be predicted through effects of the induced vortex of the canards control and the analysis of the rolling moments of tailfins due to the bank angle.

A proposal of Circular Lock Pattern Method on Smart phone (원형 스마트폰 잠금 패턴 방식 제안)

  • Im, Ji-woo;Lee, Seung-jay;Jang, Won-jun;Kwon, Hyeok-dong;Seo, Hwa-jeong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.11
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    • pp.1471-1477
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    • 2019
  • Currently, there are various security methods in smart phone. Among them, pin number and pattern lock were used long as they were used from early smart phone. However, security is weak that much. The security of pin number is slightly high, but the security of conventional pattern lock remains moderate. However, the conventional pattern lock is still used by several people because of convenience. This is because some users' smart phones don't support biometric security. The most convenient security method for devices that don't support biometric security is pattern lock. However, this method is vulnerable to shoulder surfing attack and smudge attack. Therefore, we introduce random pattern lock that solves the vulnerability of the conventional pattern lock while maintaining the convenience of the pattern lock. This is a lock method that places each point placed on the screen in a circular shape and assigns a random number to it. Therefore, If this is introduced, It's expected to solve vulnerability.

Mutual Exclusion of Lock Waiting Information for Deadlock Detection (교착(交錯) 상태(狀態)의 검출(檢出)을 위한 락 대기(待機) 정보(情報)의 상호(相互) 배제(排除))

  • Kim, Sang-Wook;Yeom, Sang-Min;Jang, Yoen-Jung;Kim, Yoon-Ho
    • Journal of Industrial Technology
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    • v.18
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    • pp.355-362
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    • 1998
  • The deadlock detector is a DBMS sub-component that examines periodically whether 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. In this paper, we propose a new method that effectively guarantees physical consistency of lock waiting information. Two primary goals of our method is to minimize the processing overhead and to maximize system concurrency.

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Lock Management in n Main-Memory DBMS

  • Kim, Sang-Wook
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.62-65
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    • 2002
  • The locking is the most widely-used concurrency control mechanism for guaranteeing logical consistency of a database where a number of transactions perform concurrently. In this Paper, we propose a new method for lock management appropriate in main-memory databases. Our method chooses the partition, a fixed-sized container for records. as a unit of locking. and directly keeps lock information within the Partition itself. These make our method enjoy the following advantages: (1) it has freedom in controlling of the trade-off between the system concurrency and the lock processing overhead by considering the characteristics of given target applications. (2) it enhances the overall system performance by eliminating the hashing overhead, a serious problem occurred in the traditional method.

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NDE of the Internal Hole Defect of Dental Composite Restoration Using Infrared Lock-In Thermography (위상잠금 열화상기법을 이용한 치과용 복합레진 수복재의 내부 홀 결함에 대한 비파괴평가)

  • Gu, Ja-Uk;Choi, Nak-Sam
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.1
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    • pp.40-45
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    • 2013
  • The purpose of this study was to detect the pin hole defect of dental composite restoration using lock-in thermography method. Amplitude and phase images of the composite resin specimens were analyzed according to the lock-in frequency and the diameter of defect area. Through the amplitude image analysis, at lock-in frequency of 0.05 Hz, defect diameters 2-5 mm exhibited the highest amplitude contrast value between defective area and sound area. The lock-in frequency range of 0.3-0.5 Hz provided good phase angle contrast for the defect area. At lock-in frequency range of 0.5 Hz, defect diameter of 5 mm exhibited the highest phase contrast value. It is concluded that the infrared lock-in thermography method verified the effectiveness for detecting the pin hole defect of dental composite restoration.

Implementation of Power Line Transmission System using A New Digital Lock Loop (디지털 지연동기루프 개발에 의한 전력선 전송시스템 구현)

  • 정주수;박재운;변건식
    • Journal of the Korea Society of Computer and Information
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    • v.4 no.2
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    • pp.105-112
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    • 1999
  • Spread Spectrum Communication is a core technique in CDMA system, but the problem for SS Communication schemes is synchronous method. There are DLL(Delay Lock Loop), Tau-dither Loop, SO(Synchronous Osillator) etc., in the sychronous method. But since there are analog operations, the setting is difficult and circuit size is large. In this paper we proposed Digital Delay Lock Loop (DDLL) and estimated it's performance through the experiment.

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HD-Tree: High performance Lock-Free Nearest Neighbor Search KD-Tree (HD-Tree: 고성능 Lock-Free NNS KD-Tree)

  • Lee, Sang-gi;Jung, NaiHoon
    • Journal of Korea Game Society
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    • v.20 no.5
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    • pp.53-64
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    • 2020
  • Supporting NNS method in KD-Tree algorithm is essential in multidimensional data applications. In this paper, we propose HD-Tree, a high-performance Lock-Free KD-Tree that supports NNS in situations where reads and writes occurs concurrently. HD-Tree reduced the number of synchronization nodes used in NNS and requires less atomic operations during Lock-Free method execution. Comparing with existing algorithms, in a multi-core system with 8 core 16 thread, HD-Tree's performance has improved up to 95% on NNS and 15% on modifying in oversubscription situation.